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Sample records for heptane

  1. Mutual diffusion coefficients of isopropanol + n-heptane and isobutanol + n-heptane

    He, Maogang; Peng, Sanguo; Zhang, Ying; Zhang, Shi; Liu, Xiangyang

    2016-01-01

    Graphical abstract: Mutual diffusion coefficients of isopropanol + n-heptane as a function of mass fraction of isopropanol. - Highlights: • D_1_2 of isopropanol + n-heptane and isobutanol + n-heptane were measured. • Effect of T, w and M of the solute on D_1_2 were analyzed. • A new correlation is proposed for the experimental data. - Abstract: The mutual diffusion coefficients of isopropanol + n-heptane and isobutanol + n-heptane were measured at different concentrations and in the temperature range from (283.15 to 323.15) K. The measurements were carried out using a digital holographic interferometry system. For all the mixtures investigated, the mutual diffusion coefficient increases as the temperature increases. At the same concentration and temperature, the mutual diffusion coefficients of isobutanol + n-heptane were lower than those of isopropanol + n-heptane due to the fact that the molecular weight of isobutanol is larger than that of isopropanol. A new correlation is proposed for the mutual diffusion coefficients of isopropanol + n-heptane and isobutanol + n-heptane. The absolute average relative deviation between the correlation and experiment is less than 1.90%.

  2. Measurement and Modeling of Surface Tensions of Asymmetric Systems: Heptane, Eicosane, Docosane, Tetracosane and their Mixtures

    Queimada, Antonio; Silva, Filipa A. E.; Caco, Ana I.

    2003-01-01

    To extend the surface tension database for heavy or asymmetric n-alkane mixtures, measurements were performed using the Wilhelmy plate method. Measured systems included the binary mixtures heptane + eicosane, heptane + docosane and heptane + tetracosane and the ternary mixture heptane + eicosane ...

  3. Measurement and Modeling of Surface Tensions of Asymmetric Systems: Heptane, Eicosane, Docosane, Tetracosane and their Mixtures

    Queimada, Antonio; Silva, Filipa A.E; Caco, Ana I.

    2003-01-01

    To extend the surface tension database for heavy or asymmetric n-alkane mixtures, measurements were performed using the Wilhelmy plate method. Measured systems included the binary mixtures heptane + eicosane, heptane + docosane and heptane + tetracosane and the ternary mixture heptane + eicosane...

  4. Replacing xylene with n-heptane for paraffin embedding.

    Stockert, J C; López-Arias, B; Del Castillo, P; Romero, A; Blázquez-Castro, A

    2012-10-01

    In standard histological technique, aromatic solvents such as xylene and toluene are used as clearing agents between ethanol dehydration and paraffin embedding. In addition, these solvents are used for de-waxing paraffin sections. Unfortunately, these solvents are harmful and therefore adequate substitutes would be useful. We suggest the use of n-heptane as a convenient substitute for xylene. Paraffin sections of rat tissues processed with n-heptane and stained with hematoxylin-eosin or Masson's trichrome showed proper embedment, well preserved morphology and excellent staining.

  5. Near infrared photoacoustic detection of heptane in synthetic air

    Duggen, Lars; Albu, Mihaela; Willatzen, Morten

    2013-01-01

    Trace contaminations of n-heptane in synthetic air is measured in the parts-per-billion (ppb) range using near infrared photoacoustic detection. We describe the fundamental theory used in the design of the photoacoustic cell for trace gas analysis and determine the detection limit of the cell...

  6. Steam reforming of heptane in a fluidized bed membrane reactor

    Rakib, Mohammad A.; Grace, John R.; Lim, C. Jim; Elnashaie, Said S. E. H.

    n-Heptane served as a model compound to study steam reforming of naphtha as an alternative feedstock to natural gas for production of pure hydrogen in a fluidized bed membrane reactor. Selective removal of hydrogen using Pd 77Ag 23 membrane panels shifted the equilibrium-limited reactions to greater conversion of the hydrocarbons and lower yields of methane, an intermediate product. Experiments were conducted with no membranes, with one membrane panel, and with six panels along the height of the reactor to understand the performance improvement due to hydrogen removal in a reactor where catalyst particles were fluidized. Results indicate that a fluidized bed membrane reactor (FBMR) can provide a compact reformer for pure hydrogen production from a liquid hydrocarbon feedstock at moderate temperatures (475-550 °C). Under the experimental conditions investigated, the maximum achieved yield of pure hydrogen was 14.7 moles of pure hydrogen per mole of heptane fed.

  7. γ-radiolysis of benzophenone in heptane solutions

    Melekhonova, I.I.; Romantsev, M.F.; Saraeva, V.V.

    1979-01-01

    The radiolysis mechanism of 8x10 -3 M solutions of benzophenon in heptane at 0 deg C and a dose of 3.8x10 20 eV/ml, is studied. The radiolysis products (benzpinacol and benzhydrol with alkyl substitution in aromatic ring) are isolated by the thin-layer chromatography. The identification of the products is performed using infrared and mass spectroscopy. The mechanism of the process is considered based on the reactions of a triplet state of benzophenon

  8. Low temperature catalytic reforming of heptane to hydrogen and syngas

    M.E.E. Abashar

    2016-09-01

    Full Text Available The production of hydrogen and syngas from heptane at a low temperature is studied in a circulating fast fluidized bed membrane reactor (CFFBMR. A thin film of palladium-based membrane is employed to the displacement of the thermodynamic equilibrium for high conversion and yield. A mathematical model is developed to simulate the reformer. A substantial improvement of the CFFBMR is achieved by implementing the thin hydrogen membrane. The results showed that almost complete conversion of heptane and 46.25% increase of exit hydrogen yield over the value without membrane are achieved. Also a wide range of the H2/CO ratio within the recommended industrial range is obtained. The phenomena of high spikes of maximum nature at the beginning of the CFFBMR are observed and explanation offered. The sensitivity analysis results have shown that the increase of the steam to carbon feed ratio can increase the exit hydrogen yield up to 108.29%. It was found that the increase of reaction side pressure at a high steam to carbon feed ratio can increase further the exit hydrogen yield by 49.36% at a shorter reactor length. Moreover, the increase of reaction side pressure has an important impact in a significant decrease of the carbon dioxide and this is a positive sign for clean environment.

  9. Separation of thiophene from heptane with ionic liquids

    Domańska, Urszula; Lukoshko, Elena Vadimovna; Królikowski, Marek

    2013-01-01

    Highlights: ► The ternary (liquid + liquid) equilibria in 1-butyl-1-methylpyrrolidinium-based ILs was measured. ► High selectivity and distribution ratio for the extraction of thiophene was found. ► [BMPYR][TCM] was proposed as entrainer for the separation process. ► Extraction of sulphur-compounds from alkanes was proposed. -- Abstract: Ionic liquids (ILs) are well known novel green solvents, which can be used for removing sulfur compounds from gasoline and diesel oils. Ternary (liquid + liquid) equilibrium data are presented for mixtures of {ionic liquid (1) + thiophene (2) + heptane (3)} at T = 298.15 K and ambient pressure to analyze the performance of the ionic liquid (IL) in the extraction of thiophene from the alkanes. Three pyrrolidinium-based ionic liquids have been studied: 1-butyl-1-methylpyrrolidinium tris(pentafluoroethyl)trifluorophosphate, ([BMPYR][FAP]), 1-butyl-1-methylpyrrolidinium tetracyanoborate, [BMPYR][TCB] and 1-butyl-1-methylpyrrolidinium tricyanomethanide, [BMPYR][TCM]. The results are discussed in terms of the selectivity and distribution ratio of separation of related systems. The immiscibility in the binary liquid systems of (thiophene + heptane) with all used ILs was observed. The [TCM] − anion in comparison with [TCB] − and [FAP] − anions shows much higher selectivity and slightly lower distribution ratio for extraction of thiophene. The non-random two liquid NRTL model was used successfully to correlate the experimental tie-lines and to calculate the phase composition error in mole fraction in the ternary systems. The average root mean square deviation (RMSD) of the phase composition was 0.047. The densities of [BMPYR][TCM] in temperature range from (298.15 to 348.15) K were measured. The data presented here show that the [BMPYR][TCM] ionic liquid can be used as an alternative solvent for the separation of thiophene from the hydrocarbon stream using solvent liquid–liquid extraction at ambient conditions

  10. Ternary (liquid + liquid) equilibria of {trifluorotris(perfluoroethyl)phosphate based ionic liquids + thiophene + heptane}

    Marciniak, Andrzej; Królikowski, Marek

    2012-01-01

    Highlights: ► Ternary (liquid + liquid) equilibria for 3 ionic liquid + thiophene + heptane systems. ► The influence of ionic liquid structure on phase diagrams is discussed. ► High selectivity for separation of heptane/thiophene is observed. - Abstract: Ternary (liquid + liquid) equilibria for three systems containing ionic liquids {(4-(2-methoxyethyl)-4-methylmorpholinium trifluorotris(perfluoroethyl)phosphate, 1-(2-methoxyethyl)-1-methylpiperidinium trifluorotris(perfluoroethyl)phosphate, 1-(2-methoxyethyl)-1-methylpyrrolidinium trifluorotris(perfluoroethyl)phosphate) + thiophene + heptane} have been determined at T = 298.15 K. All systems showed high solubility of thiophene in the ionic liquid and low solubility of heptane. The solute distribution coefficient and the selectivity were calculated for all systems. High values of selectivity were obtained. The experimental results have been correlated using NRTL model. The influence of ionic liquid structure on phase equilibria is discussed.

  11. Selective control of reformed composition of n-heptane via plasma chemistry

    Manoj Kumar Reddy, P.; Cha, Min

    2016-01-01

    This paper presents experimental results for reforming n-heptane in a temperature-controlled dielectric barrier discharge reactor to show detailed chemical composition in the products and to propose a potential method to control the product

  12. Information draft on the development of air standards for n-heptane

    NONE

    1999-01-01

    Heptane is a colourless, volatile, flammable liquid with nine isomers, the most common being n-heptane, which has a paraffinic odour. It is an ingredient in gasoline, rubber solvents, naphtha and other petroleum solvents. It occurs almost entirely in the vapour phase, where it is degraded primarily by reaction with photochemically-produced hydroxyl radicals. Short-term exposure to n-heptane at relatively low concentration resulted in vertigo and loss of coordination. Exposure to high concentration for less than 40 minutes induced prostration and loss of reflexes prior to convulsion and death. Average ambient air concentration for n-heptane in Ontario between 1988 and 1995 was 0.81 microgram/cubic meter, as measured by Environment Canada. Currently, Ontario does not have air quality criterion for n-heptane. A review of pertinent literature from world-wide sources revealed that only the states of Michigan and New York have developed air quality guidelines specifically for n-heptane, based on occupational exposure. No human or animal data was found to be available to assess the carcinogenicity of this compound. 33 refs., 1 tab., appendix.

  13. Strategies for mechanism reduction for large hydrocarbons: n-heptane

    Lu, Tianfeng; Law, Chung K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2008-07-15

    A 55-species reduced mechanism for n-heptane oxidation was derived from a 188-species skeletal mechanism, which was previously obtained from a detailed mechanism consisting of 561 species using a directed relation graph (DRG). This reduced mechanism was derived by first obtaining a skeletal mechanism with 78 species using DRG-aided sensitivity analysis. The unimportant reactions were eliminated by using the importance index defined in computational singular perturbation (CSP), with a newly posited restriction to treat each reversible reaction as a single reaction. An isomer lumping approach, also developed in the present study, then groups the isomers with similar thermal and diffusion properties so that the number of species transport equations is reduced. It was found that the intragroup mass fractions of the isomers can be approximated as constants in the present reduced mechanism, leading to a 68-species mechanism with 283 elementary reactions. Finally, 13 global quasi-steady-state species were identified using a CSP-based time-scale analysis, resulting in the 55-species reduced mechanism, with 283 elementary reactions lumped into 51 semiglobal steps. Validation of the reduced mechanism shows good agreement with the detailed mechanism for both ignition and extinction phenomena. The inadequacy of the detailed mechanism in predicting the experimental laminar flame speed is also demonstrated. (author)

  14. Ignition studies of n-heptane/iso-octane/toluene blends

    Javed, Tamour

    2016-07-09

    Ignition delay times of four ternary blends of n-heptane/iso-octane/toluene, referred to as Toluene Primary Reference Fuels (TPRFs), have been measured in a high-pressure shock tube and in a rapid compression machine. The TPRFs were formulated to match the research octane number (RON) and motor octane number (MON) of two high-octane gasolines and two prospective low-octane naphtha fuels. The experiments were carried out over a wide range of temperatures (650–1250 K), at pressures of 10, 20 and 40 bar, and at equivalence ratios of 0.5 and 1.0. It was observed that the ignition delay times of these TPRFs exhibit negligible octane dependence at high temperatures (T > 1000 K), weak octane dependence at low temperatures (T < 700 K), and strong octane dependence in the negative temperature coefficient (NTC) regime. A detailed chemical kinetic model was used to simulate and interpret the measured data. It was shown that the kinetic model requires general improvements to better predict low-temperature conditions and particularly requires improvements for high sensitivity (high toluene concentration) TPRF blends. These datasets will serve as important benchmark for future gasoline surrogate mechanism development and validation. © 2016 The Combustion Institute

  15. Reaction Mechanisms and HCCI Combustion Processes of Mixtures of n-Heptane and the Butanols

    Hu eWang

    2015-03-01

    Full Text Available A reduced primary reference fuel (PRF-Alcohol-Di-tert-butyl Peroxide (DTBP mechanism with 108 species and 435 reactions, including sub-mechanisms of PRF, methanol, ethanol, DTBP and the four butanol isomers, is proposed for homogeneous charge compression ignition (HCCI engine combustion simulations of butanol isomers/n-heptane mixtures. HCCI experiments fuelled with butanol isomer/n-heptane mixtures on two different engines are conducted for the validation of proposed mechanism. The mechanism has been validated against shock tube ignition delays, laminar flame speeds, species profiles in premixed flames and engine HCCI combustion data, and good agreements with experimental results are demonstrated under various validation conditions. It is found that although the reactivity of neat tert-butanol is the lowest, mixtures of tert-butanol/n-heptane exhibit the highest reactivity among the butanol isomer/n-heptane mixtures if the n-heptane blending ratio exceeds 20% (mole. Kinetic analysis shows that the highest C-H bond energy in the tert-butanol molecule is partially responsible for this phenomenon. It is also found that the reaction tC4H9OH+CH3O2 =tC4H9O+CH3O2H plays important role and eventually produces the OH radical to promote the ignition and combustion. The proposed mechanism is able to capture HCCI combustion processes of the butanol/n-heptane mixtures under different operating conditions. In addition, the trend that tert-butanol /n-heptane has the highest reactivity is also captured in HCCI combustion simulations. The results indicate that the current mechanism can be used for HCCI engine predictions of PRF and alcohol fuels.

  16. Transition of carbon nanostructures in heptane diffusion flames

    Hu, Wei-Chieh [National Cheng Kung University, Department of Mechanical Engineering (China); Hou, Shuhn-Shyurng [Kun Shan University, Department of Mechanical Engineering (China); Lin, Ta-Hui, E-mail: thlin@mail.ncku.edu.tw [National Cheng Kung University, Department of Mechanical Engineering (China)

    2017-02-15

    The flame synthesis has high potential in industrial production of carbon nanostructure (CNS). Unfortunately, the complexity of combustion chemistry leads to less controlling of synthesized products. In order to improve the understanding of the relation between flames and CNSs synthesized within, experiments were conducted through heptane flames in a stagnation-point liquid-pool system. The operating parameters for the synthesis include oxygen supply, sampling position, and sampling time. Two kinds of nanostructures were observed, carbon nanotube (CNT) and carbon nano-onion (CNO). CNTs were synthesized in a weaker flame near extinction. CNOs were synthesized in a more sooty flame. The average diameter of CNTs formed at oxygen concentration of 15% was in the range of 20–30 nm. For oxygen concentration of 17%, the average diameter of CNTs ranged from 24 to 27 nm, while that of CNOs was around 28 nm. For oxygen concentration of 19%, the average diameter of CNOs produced at the sampling position 0.5 mm below the flame front was about 57 nm, while the average diameters of CNOs formed at the sampling positions 1–2.5 mm below the flame front were in the range of 20–25 nm. A transition from CNT to CNO was observed by variation of sampling position in a flame. We found that the morphology of CNS is directly affected by the presence of soot layer due to the carbonaceous environment and the growth mechanisms of CNT and CNO. The sampling time can alter the yield of CNSs depending on the temperature of sampling position, but the morphology of products is not affected.

  17. The 7-azanorbornane nucleus of epibatidine: 7-azabicyclo[2.2.1]heptan-7-ium chloride

    Sergey N. Britvin

    2017-09-01

    Full Text Available 7-Azabicyclo[2.2.1]heptane (7-azanorbornane is a bridged heterocyclic nucleus found in epibatidine, the alkaloid isolated from the skin of the tropical poison frog Epipedobates tricolor. Since epibatidine is known as one of the most potent acetylcholine nicotinic receptor agonists, a plethora of literature has been devoted to this alkaloid. However, there are no structural data on the unsubstituted 7-azanorbornane, the parent bicyclic ring of epibatidine and its derivatives. We herein present the structural characterization of the 7-azabicyclo[2.2.1]heptane parent ring as its hydrochloride salt, namely 7-azabicyclo[2.2.1]heptan-7-ium chloride, C6H12N+·Cl−. The compete cation is generated by a crystallographic mirror plane with the N atom lying on the mirror, as does the chloride anion. In the crystal, the cations are linked to the anions by N—H...Cl hydrogen bonds, which generate [001] chains.

  18. High-pressure density measurements for the binary system ethanol plus heptane

    Watson, G.; Zeberg-Mikkelsen, Claus Kjær; Baylaucq, A.

    2006-01-01

    The density of the asymmetrical binary system composed of ethanol and heptane has been measured (630 points) for nine different compositions including the pure compounds at five temperatures in the range (293.15 to 333.15) K and 14 isobars up to 65 MPa with a vibrating-tube densimeter, The experi......The density of the asymmetrical binary system composed of ethanol and heptane has been measured (630 points) for nine different compositions including the pure compounds at five temperatures in the range (293.15 to 333.15) K and 14 isobars up to 65 MPa with a vibrating-tube densimeter...

  19. Excess Molar Volumes of (Heptane + 1-Chloropentane) at Elevated Temperatures and High Pressures

    Morávková, Lenka; Aim, Karel; Linek, Jan

    2002-01-01

    Roč. 34, č. 9 (2002), s. 1377-1386 ISSN 0021-9614 R&D Projects: GA ČR GA203/00/0600 Keywords : heptane * 1-chloropentane * binary mixtures Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.000, year: 2002

  20. Excess Molar Volumes of (Heptane + 1-Chlorobutane) at Elevated Temperatures and High Pressures

    Morávková, Lenka; Linek, Jan

    2002-01-01

    Roč. 34, č. 9 (2002), s. 1397-1405 ISSN 0021-9614 R&D Projects: GA ČR GA203/00/0600 Keywords : heptane * 1-chlorobutane * thermodynamics Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.000, year: 2002

  1. Ozone production by a dc corona discharge in air contaminated by n-heptane

    Pekarek, S

    2008-01-01

    Beneficial purposes of ozone such as elimination of odours, harmful bacteria and mildew can be used for transportation of food, fruits and vegetables with the aim to extend their storage life. To date the main technique used for this purpose in the transportation of these commodities, e.g. by trucks, was cooling. Here a combination of cooling together with the supply of ozone into containers with these commodities is considered. For these purposes we studied the effect of air contamination by n-heptane (part of automotive fuels) and humidity on ozone production by a dc hollow needle to mesh corona discharge. We found that, for both polarities of the needle electrode, addition of n-heptane to air (a) decreases ozone production; (b) causes discharge poisoning to occur at lower current than for air; (c) does not substantially influence the current for which the ozone production reaches the maximum. Finally the maximum ozone production for the discharge in air occurs for the same current as the maximum ozone production for the discharge contaminated by n-heptane. We also found that humidity decreases ozone production from air contaminated by n-heptane irrespective of the polarity of the coronating needle electrode. This dependence is stronger for the discharge with the needle biased positively

  2. Nanosecond Discharge in Bubbled Liquid n-Heptane: Effects of Gas Composition and Water Addition

    Hamdan, Ahmad; Cha, Min

    2016-01-01

    in liquid n-heptane with single and double gaseous bubbles in the gap between electrodes. We introduce discharge probability (DP) to characterize the stochastic nature of the discharges, and we investigate the dependence of DP on the gap distance, applied

  3. Investigation of Chemical Kinetics on Soot Formation Event of n-Heptane Spray Combustion

    Pang, Kar Mun; Jangi, Mehdi; Bai, Xue-Song

    2014-01-01

    . Numerical computation is performed using OpenFOAM and chemistry coordinate mapping (CCM) approach is used to expedite the calculation. Three n-heptane kinetic mechanisms with different chemistry sizes and comprehensiveness in oxidation pathways and soot precursor formation are adopted. The three examined...

  4. Surface tension of heptane, decane, hexadecane, eicosane, and some of their binary mixtures

    Rolo, Lara I.; Caco, Ana I.; Queimada, Antonio

    2002-01-01

    Surface tension measurements were performed by the Wilhelmy plate method. Measured systems included pure heptane, decane, hexadecane, eicosane, and some of their binary mixtures at temperatures from 293.15 K to 343.15 K with an average absolute deviation of 1.6%. The results were compared with a ...

  5. Effect of oxygen content on n-heptane auto-ignition characteristics in a HCCI engine

    Wu, Zhijun; Kang, Zhe; Deng, Jun; Hu, Zongjie; Li, Liguang

    2016-01-01

    Highlights: • n-Heptane HCCI combustion under air and oxygen intake was compared. • n-Heptane auto-ignition postponed due to higher specific heat capacity as oxygen increase. • The increment of heat release fraction during low temperature reaction is studied. • Oxygen enrichment lead to suppressed negative temperature coefficient. • The mechanism of low temperature reaction enhancement as oxygen increase is investigated. - Abstract: To take maximum advantage of the high efficiency of homogeneous charge compression ignition combustion mode and internal combustion Rankine cycle concept, in this study, the n-heptane auto-ignition characteristics have been investigated using a compression ignition internal combustion Rankine cycle engine test bench and a zero-dimensional thermodynamic model coupled with a detailed kinetic model. The n-heptane auto-ignition process shows that under both air and oxygen intake, a typical two-stage combustion in which oxygen enrichment has very minor effects on the n-heptane high temperature reaction. The higher specific heat capacity of oxygen compared with nitrogen leads to an overall increased specific heat capacity, which lowers the in-cylinder temperature during compression stroke, thereby delaying the low temperature reaction initial timing. The higher oxygen content also improves the H-atom abstraction, first O_2 addition, second O_2 addition and peroxyalkylhydroperoxide isomerization, thereby improving the overall reaction rate and the heat release fraction of low temperature reaction. As a result, the in-cylinder temperature at the end of low temperature reaction also increases, thereby shortening significantly the negative temperature coefficient duration compared with a combustion cycle using air as oxidizer.

  6. Synthesis of Carbon–Metal Multi-Strand Nanocomposites by Discharges in Heptane Between Two Metallic Electrodes

    Hamdan, Ahmad; Kabbara, H.; Courty, M.-A.; Cha, Min; Martinez, J.-M.; Belmonte, T.

    2017-01-01

    We studied composite wires assembled from electric field-driven nanoparticles in a dielectric liquid (heptane) to elucidate the exact processes and controlling factors involved in the synthesis of the multi-phase nanocomposites. Filamentary wires

  7. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    Rajagopal K.

    2004-01-01

    Full Text Available The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10-6 g/ml and 10-7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20°C. We found that the average size of the particles remained constant with time and increase with an increase in amount of n-heptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models.

  8. Intermediate temperature heat release in an HCCI engine fueled by ethanol/n-heptane mixtures: An experimental and modeling study

    Vuilleumier, David

    2014-03-01

    This study examines intermediate temperature heat release (ITHR) in homogeneous charge compression ignition (HCCI) engines using blends of ethanol and n-heptane. Experiments were performed over the range of 0-50% n-heptane liquid volume fractions, at equivalence ratios 0.4 and 0.5, and intake pressures from 1.4bar to 2.2bar. ITHR was induced in the mixtures containing predominantly ethanol through the addition of small amounts of n-heptane. After a critical threshold, additional n-heptane content yielded low temperature heat release (LTHR). A method for quantifying the amount of heat released during ITHR was developed by examining the second derivative of heat release, and this method was then used to identify trends in the engine data. The combustion process inside the engine was modeled using a single-zone HCCI model, and good qualitative agreement of pre-ignition pressure rise and heat release rate was found between experimental and modeling results using a detailed n-heptane/ethanol chemical kinetic model. The simulation results were used to identify the dominant reaction pathways contributing to ITHR, as well as to verify the chemical basis behind the quantification of the amount of ITHR in the experimental analysis. The dominant reaction pathways contributing to ITHR were found to be H-atom abstraction from n-heptane by OH and the addition of fuel radicals to O2. © 2013 The Combustion Institute.

  9. Intermediate temperature heat release in an HCCI engine fueled by ethanol/n-heptane mixtures: An experimental and modeling study

    Vuilleumier, David; Kozarac, Darko; Mehl, Marco; Saxena, Samveg; Pitz, William J.; Dibble, Robert W.; Chen, Jyhyuan; Sarathy, Mani

    2014-01-01

    This study examines intermediate temperature heat release (ITHR) in homogeneous charge compression ignition (HCCI) engines using blends of ethanol and n-heptane. Experiments were performed over the range of 0-50% n-heptane liquid volume fractions, at equivalence ratios 0.4 and 0.5, and intake pressures from 1.4bar to 2.2bar. ITHR was induced in the mixtures containing predominantly ethanol through the addition of small amounts of n-heptane. After a critical threshold, additional n-heptane content yielded low temperature heat release (LTHR). A method for quantifying the amount of heat released during ITHR was developed by examining the second derivative of heat release, and this method was then used to identify trends in the engine data. The combustion process inside the engine was modeled using a single-zone HCCI model, and good qualitative agreement of pre-ignition pressure rise and heat release rate was found between experimental and modeling results using a detailed n-heptane/ethanol chemical kinetic model. The simulation results were used to identify the dominant reaction pathways contributing to ITHR, as well as to verify the chemical basis behind the quantification of the amount of ITHR in the experimental analysis. The dominant reaction pathways contributing to ITHR were found to be H-atom abstraction from n-heptane by OH and the addition of fuel radicals to O2. © 2013 The Combustion Institute.

  10. A comparison of sulfur mustard and heptane penetrating a dipalmitoylphosphatidylcholine bilayer membrane

    Mueller, Thomas J., E-mail: t.mueller@theo.chemie.tu-darmstadt.de [Theoretische Physikalische Chemie, Eduard-Zintl-Institut fuer Anorganische und Physikalische Chemie, Technische Universitaet Darmstadt, Petersenstrasse 20, 64287 Darmstadt (Germany); Mueller-Plathe, Florian [Theoretische Physikalische Chemie, Eduard-Zintl-Institut fuer Anorganische und Physikalische Chemie, Technische Universitaet Darmstadt, Petersenstrasse 20, 64287 Darmstadt (Germany)

    2009-08-30

    In the present molecular dynamics simulations we study the chemical warfare agent sulfur mustard (bis(2-chloroethyl) sulfide) and the alkane heptane inserted into a dipalmitoylphosphatidylcholine (DPPC) bilayer, a generic model for a biological membrane. We investigate the diffusion, the orientation, the preferred positioning, and the end-to-end distance of the solutes within the membrane as well as the corresponding coupling times. We compare results of equilibrium simulations and simulation at different external forces, which drag the solutes through the membrane. These properties lead to a general comparison of the rotational and translational behaviors of the two solutes during the penetration of the membrane. We show that sulfur mustard, due to its atomic charge polarization, its bigger flexibility and its smaller molecular volume, is the faster moving molecule within the membrane. In last consequence, we show that this leads to different limits for the transport mechanism as observed in these simulations. For heptane the hindrance to penetrate into the membrane is significantly higher than for sulfur mustard. In contrast to heptane molecules, which spend the most of the time penetrating the tail groups, sulfur mustard needs more time to escape the tail group-head group interface of the membrane.

  11. Selective control of reformed composition of n-heptane via plasma chemistry

    Manoj Kumar Reddy, P.

    2016-08-23

    This paper presents experimental results for reforming n-heptane in a temperature-controlled dielectric barrier discharge reactor to show detailed chemical composition in the products and to propose a potential method to control the product composition. Reformed products of n-heptane and water mixture in an inert Ar feed could be identified as hydrogen, carbon monoxide, oxygenates, and various hydrocarbons, having a wide range of carbon numbers. To selectively increase production of short-chain hydrocarbons, Ar was replaced by CH4. An increased pool of methyl radicals, via plasma chemistry of CH4, might facilitate to stabilize intermediate alkyls (R) into RCH3, which successfully increased short-chain hydrocarbon concentration. When CO2 was supplied instead of Ar (to provide enriched OH and O radicals), significantly higher oxygenate concentrations were obtained through the stabilization of alkyls as ROH (alcohol), and RC([Formula presented])R′ (ketone). The use of methane and carbon dioxide as feed to tailor the products of plasma-assisted reforming of n-heptane with methyl (CH3), or O radicals, is successfully demonstrated in the presence of water vapor. Detailed product analysis, such as product selection, rates and energy efficiency using a gas chromatograph and a gas chromatography mass spectrometer, will be elaborated upon. © 2016 Elsevier Ltd

  12. Thermodynamic study of (heptane + amine) mixtures. II. Excess and partial molar volumes at 298.15 K

    Lepori, Luciano; Gianni, Paolo; Spanedda, Andrea; Matteoli, Enrico

    2011-01-01

    Research highlights: → Excess and partial molar volumes of primary (amines + heptane) mixtures. → Excess volumes are positive for small size amines and decrease as the size increases. → Group contributions to predict the partial molar volumes of amines in heptane. → The void volume is larger for branched than for linear amines in heptane. - Abstract: Excess molar volumes V E at 298.15 K were determined by means of a vibrating tube densimeter for binary mixtures of heptane + primary n-alkyl (C 3 to C 10 ) and branched amines (iso-propyl-, iso-, sec-, and tert-butyl-, iso-, tert-pentyl-, and pentan-3-amine) in the whole composition range. The apparent molar volumes of solid dodecyl- and tetradecylamine in heptane dilute solution were also determined. The V E values were found positive for mixtures involving C 3 to C 8 linear amines, with V E decreasing with chain lengthening. Heptane + nonyl and decylamine showed s-shaped, markedly asymmetric, curves. Mixtures with branched C 3 to C 5 amines displayed positive V E 's larger than those observed in the mixtures of the corresponding linear isomers. Partial molar volumes V o at infinite dilution in heptane were evaluated for the examined amines and compared with those of alkanes and alkanols taken from the literature. An additivity scheme, based on the intrinsic volume approach, was applied to estimate group (CH 3 , CH 2 , CH, C, NH 2 , and OH) contributions to V o . The effect of branching on V o and the limiting slope of the apparent excess molar volumes were evaluated and discussed in terms of solute-solvent and solute-solute interactions.

  13. The Role of Hydrogen Bonding on Laminar Burning Velocity of Hydrous and Anhydrous Ethanol Fuel with Small Addition of n-Heptane

    I Made Suarta

    2016-01-01

    Full Text Available The molecular structure of mixed hydrous and anhydrous ethanol with up to 10% v n-heptane had been studied. The burning velocity was examined in a cylindrical explosion combustion chamber. The result showed that the burning velocity of hydrous ethanol is higher than anhydrous ethanol and n-heptane at stoichiometric, rich, and very rich mixtures. The burning velocity of hydrous ethanol with n-heptane drops drastically compared to the burning velocity of anhydrous ethanol with n-heptane. It is caused by two reasons. Firstly, there was a composition change of azeotropic hydrous ethanol molecules within the mixture of fuel. Secondly, at the same volume the number of ethanol molecules in hydrous ethanol was less than in anhydrous ethanol at the same composition of the n-heptane in the mixture. At the mixture of anhydrous ethanol with n-heptane, the burning velocity decreases proportionally to the addition of the n-heptane composition. The burning velocity is between the velocities of anhydrous ethanol and n-heptane. It shows that the burning velocity of anhydrous ethanol mixed with n-heptane is only influenced by the mixture composition.

  14. Nanosecond Discharge in Bubbled Liquid n-Heptane: Effects of Gas Composition and Water Addition

    Hamdan, Ahmad

    2016-08-30

    Recently, an aqueous discharge reactor was developed to facilitate reformation of liquid fuels by in-liquid plasma. To gain a microscopic understanding of the physical elements behind this aqueous reactor, we investigate nanosecond discharges in liquid n-heptane with single and double gaseous bubbles in the gap between electrodes. We introduce discharge probability (DP) to characterize the stochastic nature of the discharges, and we investigate the dependence of DP on the gap distance, applied voltage, gaseous bubble composition, and the water content in n-heptane/distilled-water emulsified mixtures. Propagation of a streamer through the bubbles indicates no discharges in the liquids. DP is controlled by the properties of the gaseous bubble rather than by the composition of the liquid mixture in the gap with a single bubble; meanwhile, DP is determined by the dielectric permittivity of the liquid mixture in the gap with double bubbles, results that are supported by static electric field simulations. We found that a physical mechanism of increasing DP is caused by an interaction between bubbles and an importance of the dielectric permittivity of a liquid mixture on the local enhancement of field intensity. We also discuss detailed physical characteristics, such as plasma lifetime and electron density within the discharge channel, by estimating from measured emissions with a gated-intensified charge-coupled device and by using spectroscopic images, respectively. © 1973-2012 IEEE.

  15. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Garcia-Sanchez, Fernando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)]. E-mail: fgarcias@imp.mx; Eliosa-Jimenez, Gaudencio [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Silva-Oliver, Guadalupe [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico); Godinez-Silva, Armando [Laboratorio de Termodinamica, Programa de Ingenieria Molecular, Instituto Mexicano del Petroleo, Eje Central Lazaro Cardenas 152, 07730 Mexico, D.F. (Mexico)

    2007-06-15

    In this work, new (vapor + liquid) equilibrium data for the (N{sub 2} + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N{sub 2} + n-heptane) system.

  16. High-pressure (vapor + liquid) equilibria in the (nitrogen + n-heptane) system

    Garcia-Sanchez, Fernando; Eliosa-Jimenez, Gaudencio; Silva-Oliver, Guadalupe; Godinez-Silva, Armando

    2007-01-01

    In this work, new (vapor + liquid) equilibrium data for the (N 2 + n-heptane) system were experimentally measured over a wide temperature range from (313.6 to 523.7) K and pressures up to 50 MPa. A static-analytic apparatus with visual sapphire windows and pneumatic capillary samplers was used in the experimental measurements. Equilibrium phase compositions and (vapor + liquid) equilibrium ratios are reported. The new results were compared with those reported by other authors. The comparison showed that the pressure-composition data reported in this work are less scattered than those determined by others. Hence, the results demonstrate the reliability of the experimental apparatus at high temperatures and pressures. The experimental data were represented with the PR and PC-SAFT equations of state by using one-fluid mixing rules and a single temperature independent interaction parameter. Results of the representation showed that the PC-SAFT equation was superior to the PR equation in correlating the experimental data of the (N 2 + n-heptane) system

  17. Pervaporative desulfurization of gasoline – separation of thiophene/n-heptane mixture / Perwaporacyjne odsiarczanie benzyny – separacja mieszanin tiofen/n-heptan

    Rychlewska Katarzyna

    2015-06-01

    Full Text Available W pracy zaprezentowano dotychczasowe osiągnięcia w perwaporacyjnym odsiarczaniu benzyny krakingowej. Przedstawiono kryteria wstępnego doboru materiału warstwy aktywnej membran. Omówiono ponadto wpływ typowych węglowodorów oraz związków siarkoorganicznych obecnych w benzynie krakingowej na selektywność i właściwości transportowe membran jak również wpływ parametrów procesowych (temperatury nadawy, ciśnienia po stronie permeatu oraz szybkości przepływu nadawy na efektywność procesu perwaporacyjnego odsiarczania. W pracy przedstawiono możliwość zastosowania komercyjnych membran kompozytowych z warstwą aktywną wykonaną z poli(dimetylosiloksanu (PDMS w procesie perwaporacyjnego odsiarczania benzyny pochodzącej z fluidalnego krakingu katalitycznego (FCC. Określono wpływ stężenia organicznych związków siarki na efektywność ich usuwania z organicznych mieszanin tiofen/n-heptan metodą perwaporacji próżniowej.

  18. Binary, ternary and quaternary liquid-liquid equilibria in 1-butanol, oleic acid, water and n-heptane mixtures

    Winkelman, J. G. M.; Kraai, G. N.; Heeres, H. J.

    2009-01-01

    This work reports on liquid-liquid equilibria in the system 1-butanol, oleic acid, water and n-heptane used for biphasic, lipase catalysed esterifications. The literature was studied on the mutual solubility in binary systems of water and each of the organic components. Experimental results were

  19. Solvent extraction of aromatic sulfur compounds from n-heptane using the 1-ethyl-3-methylimidazolium tricyanomethanide ionic liquid

    Królikowski, Marek; Walczak, Klaudia; Domańska, Urszula

    2013-01-01

    Highlights: • LLE data for (EMIMTCM + thiophene/benzothiophene + n-heptane) were determined. • High S and β for the extraction of thiophene/benzothiophene from n-heptane was found. • Results of S and β were compared with available literature. • The NRTL model satisfactorily correlates the LLE data. -- Abstract: The ionic liquid 1-ethyl-3-methylimidazolium tricyanomethanide ([EMIM][TCM]) has been tested as a solvent for the separation of sulfur compounds from aliphatic hydrocarbon. Liquid–liquid phase equilibrium data have been determined for ternary systems containing the ionic liquid, thiophene or benzothiophene and n-heptane. The influence of temperature on the separation of thiophene from n-heptane was determined. High solubility of sulfur compounds and practical immiscibility of aliphatic hydrocarbon in ionic liquid have been found. The values of selectivity and solute distribution ratios have been calculated for all systems and compared with literature data for other 1-ethyl-3-methylimidazolium-based ionic liquids. High values of selectivity were obtained. The experimental data were correlated using the NRTL equation, and the binary interaction parameters have been reported. The phase equilibria diagrams for the ternary mixtures including the experimental and calculated tie-lines have been presented

  20. n-Heptane cool flame chemistry: Unraveling intermediate species measured in a stirred reactor and motored engine

    Wang, Zhandong; Chen, Bingjie; Moshammer, Kai; Popolan-Vaida, Denisia M.; Sioud, Salim; Shankar, Vijai; Vuilleumier, David; Tao, Tao; Ruwe, Lena; Brä uer, Eike; Hansen, Nils; Dagaut, Philippe; Kohse-Hö inghaus, Katharina; Raji, Misjudeen; Sarathy, Mani

    2017-01-01

    -OTMS, which has ultra-high mass resolving power and provides an accurate elemental C/H/O composition of the intermediate species. Furthermore, the results show that the species formed during the partial oxidation of n-heptane in the CFR engine are very similar

  1. Liquid-liquid extraction systems of benzoic acid in water, heptane, methylbenzene or trichloroethylene as co-solvent

    Visscher, F.; Gaakeer, W.A.; Granados Mendoza, P.; Croon, de M.H.J.M.; Schaaf, van der J.; Schouten, J.C.

    2011-01-01

    Equilibrium data at (293 ± 2) K are presented for benzoic acid in water and three different organic phases (heptane, methylbenzene, and trichloroethylene). The monomeric partition constant, KPMON, and the dimerization constant, KD, for the organic phase were determined at 293 K. For the

  2. Forced convective and subcooled flow boiling heat transfer to pure water and n-heptane in an annular heat exchanger

    Peyghambarzadeh, S.M.; Sarafraz, M.M.; Vaeli, N.; Ameri, E.; Vatani, A.; Jamialahmadi, M.

    2013-01-01

    Highlights: ► The cooling performance of water and n-heptane is compared during subcooled flow boiling. ► Although n-heptane leaves the heat exchanger warmer it has a lower heat transfer coefficient. ► Flow rate, heat flux and degree of subcooling have direct effect on heat transfer coefficient. ► The predictions of some correlations are evaluated against experimental data. - Abstract: In this research, subcooled flow boiling heat transfer coefficients of pure n-heptane and distilled water at different operating conditions have been experimentally measured and compared. The heat exchanger consisted of vertical annulus which is heated from the inner cylindrical heater with variable heat flux (less than 140 kW/m 2 ). Heat flux is varied so that two different flow regimes from single phase forced convection to nucleate boiling condition are created. Meanwhile, liquid flow rate is changed in the range of 2.5 × 10 −5 –5.8 × 10 −5 m 3 /s to create laminar up to transition flow regimes. Three subcooling levels including 10, 20 and 30 °C are also considered. Experimental results demonstrated that subcooled flow boiling heat transfer coefficient increases when higher heat flux, higher liquid flow rate and greater subcooling level are applied. Furthermore, influence of the operating conditions on the bubbles generation on the heat transfer surface is also discussed. It is also shown that water is better cooling fluid in comparison with n-heptane

  3. Inhibition of corrosion of carbon steel by heptane sulphonic acid – Zn2+ system

    C. MARY ANBARAS

    2012-03-01

    Full Text Available Corrosion inhibition of carbon steel in dam water by sodium heptane sulphonate (SHS and zinc ion system was investigated using weight loss and potentiodynamic polarization methods. Results of weight loss method indicated that inhibition efficiency (IE increased as the inhibitor concentration increased. A synergistic effect existed between SHS and Zn2+. The influence of sodium potassium tartrate (SPT on the IE of the SHS-Zn2+ system was evaluated. As the immersion period increased, the IE decreased. Polarization study revealed that SHS-Zn2+ system functioned as a cathodic inhibitor. AC impedance spectra revealed that a protective film was formed on the metal surface. The nature of the metal surface was analyzed by FTIR spectra, SEM and AFM analyses.

  4. Reduced Gasoline Surrogate (Toluene/n-Heptane/iso-Octane) Chemical Kinetic Model for Compression Ignition Simulations

    Sarathy, Mani

    2018-04-03

    Toluene primary reference fuel (TPRF) (mixture of toluene, iso-octane and heptane) is a suitable surrogate to represent a wide spectrum of real fuels with varying octane sensitivity. Investigating different surrogates in engine simulations is a prerequisite to identify the best matching mixture. However, running 3D engine simulations using detailed models is currently impossible and reduction of detailed models is essential. This work presents an AramcoMech reduced kinetic model developed at King Abdullah University of Science and Technology (KAUST) for simulating complex TPRF surrogate blends. A semi-decoupling approach was used together with species and reaction lumping to obtain a reduced kinetic model. The model was widely validated against experimental data including shock tube ignition delay times and premixed laminar flame speeds. Finally, the model was utilized to simulate the combustion of a low reactivity gasoline fuel under partially premixed combustion conditions.

  5. Densities and viscosities for binary mixtures of n-heptane with alcohols at different temperatures

    Budeanu Maria Magdalena

    2017-01-01

    Full Text Available Densities (ρ and viscosities (η of the binary systems n-heptane with alcohols (ethanol, propan-1-ol and propan-2-ol were measured at temperatures between 288.15 and 308.15 K and at atmospheric pressure, over the whole composition range. The excess values of molar volume (VE and viscosity (ηE were calculated from experimental measurements. The excess functions of the binary systems were fitted to Redlich–Kister Equation. Comparison between experimental excess molar volume and the one calculated from Flory and Prigogine–Flory–Patterson theories, has also been done. The viscosity results were fitted to the equations of Grunberg–Nissan, Heric–Brewer, Jouyban–Acree and McAllister. Also, the activation energies of viscous flow have been obtained and their variations with compositions have been discussed.

  6. Efficacy of Ultrasonic Homogenization in the Separation of Benzene-n-Heptane Mixture by Liquid Membrane

    Kim, B.S.; Chung, T.S. [Department of Chemical Engineering, Sung Kyun Kwan University, Seoul (Korea)

    1999-04-01

    In the separation of benzene-n-heptane mixture by liquid membrane, the efficacy of ultrasonic homogenization in emulsification was studied with two anionic surfactants. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether sulfate. The two anionic surfactants used were triethanolamine lauryl sulfate and sodium polyoxyethylene(2) lauryl ether stifle. The highest value of the separation factor obtained by ultrasonic homogenization was approximately three times as large as that for triethanolamine lauryl sulfate and one and a half times as large as that for sodium polyoxyethylene(2) lauryl sulfate when the mechanical stirring was used on the same operational conditions. The lowest membrane breakup was observed when the highest value of the separation factor was achieved with sodium polyoxyethylene(2) lauryl sulfate. 14 refs., 7 figs., 1 tab.

  7. Reduced Gasoline Surrogate (Toluene/n-Heptane/iso-Octane) Chemical Kinetic Model for Compression Ignition Simulations

    Sarathy, Mani; Atef, Nour; Alfazazi, Adamu; Badra, Jihad; Zhang, Yu; Tzanetakis, Tom; Pei, Yuanjiang

    2018-01-01

    Toluene primary reference fuel (TPRF) (mixture of toluene, iso-octane and heptane) is a suitable surrogate to represent a wide spectrum of real fuels with varying octane sensitivity. Investigating different surrogates in engine simulations is a prerequisite to identify the best matching mixture. However, running 3D engine simulations using detailed models is currently impossible and reduction of detailed models is essential. This work presents an AramcoMech reduced kinetic model developed at King Abdullah University of Science and Technology (KAUST) for simulating complex TPRF surrogate blends. A semi-decoupling approach was used together with species and reaction lumping to obtain a reduced kinetic model. The model was widely validated against experimental data including shock tube ignition delay times and premixed laminar flame speeds. Finally, the model was utilized to simulate the combustion of a low reactivity gasoline fuel under partially premixed combustion conditions.

  8. Direct numerical simulations of ignition of a lean n-heptane/air mixture with temperature and composition inhomogeneities relevant to HCCI and SCCI combustion

    Luong, Minh Bau; Yu, Gwang Hyeon; Lu, Tianfeng; Chung, Suk-Ho; Yoo, Chun Sang

    2015-01-01

    The effects of temperature and composition stratifications on the ignition of a lean n-heptane/air mixture at three initial mean temperatures under elevated pressure are investigated using direct numerical simulations (DNSs) with a 58-species

  9. Quaternary isobaric (vapor + liquid + liquid) equilibrium and (vapor + liquid) equilibrium for the system (water + ethanol + cyclohexane + heptane) at 101.3 kPa

    Pequenin, Ana; Asensi, Juan Carlos; Gomis, Vicente

    2011-01-01

    Highlights: → Water-ethanol-cyclohexane-heptane and water-cyclohexane-heptane isobaric VLLE. → Isobaric experimental data were determined at 101.3 kPa. → A dynamic recirculating still with an ultrasonic homogenizer was used. → The quaternary system does not present quaternary azeotropes. - Abstract: Experimental isobaric (vapor + liquid + liquid) and (vapor + liquid) equilibrium data for the ternary system {water (1) + cyclohexane (2) + heptane (3)} and the quaternary system {water (1) + ethanol (2) + cyclohexane (3) + heptane (4)} were measured at 101.3 kPa. An all-glass, dynamic recirculating still equipped with an ultrasonic homogenizer was used to determine the VLLE. The results obtained show that the system does not present quaternary azeotropes. The point-by-point method by Wisniak for testing the thermodynamic consistency of isobaric measurements was used to test the equilibrium data.

  10. On the dose-rate effect of ionizing radiations on the initial radiation-chemical yield of paramagnetic centers upon low-temperature radiolysis of n-heptane

    Mozhaev, P.S.; Kiryukhin, D.P.; Kuzina, S.I.

    1995-01-01

    In this work the authors report on an experimental study of the initial regions of dose dependence of paramagnetic centers in n-heptane upon varying the dose rate from 0.035 to 2.3 x 10 3 Gy/s. The buildup at 77 K of paramagnetic centers in n-heptane was studied in outgassed samples placed in Luch-2 glass cells

  11. Experimental and theoretical excess molar enthalpies of ternary and binary mixtures containing 2-Methoxy-2-Methylpropane, 1-propanol, heptane

    Mato, Marta M.; Cebreiro, Susana M.; Paz Andrade, María Inmaculada; Legido, José Luis

    2013-01-01

    Highlights: • Experimental enthalpies for the ternary system MTBE + propanol + heptane were measured. • No experimental ternary values were found in the currently available literature. • Experimental enthalpies for the binary system propanol + heptane were measured. • Excess molar enthalpies are positive over the whole range of composition. • The ternary contribution is also positive, and the representation is asymmetric. -- Abstract: Excess molar enthalpies, at the temperature of 298.15 K and atmospheric pressure, have been measured for the ternary system {x 1 2-Methoxy-2-Methylpropane (MTBE) + x 2 1-propanol + (1 − x 1 − x 2 ) heptane}, over the whole composition range. Also, experimental data of excess molar enthalpy for the involved binary mixture {x 1-propanol + (1 − x) heptane} at the 298.15 K and atmospheric pressure, are reported. We are not aware of any previous experimental measurement of excess enthalpy in the literature for the ternary system presented in this study. Values of the excess molar enthalpies were measured using a Calvet microcalorimeter. The ternary contribution to the excess enthalpy was correlated with the equation due to Morris et al. (1975) [15], and the equation proposed by Myers–Scott (1963) [14] was used to fitted the experimental binary mixture measured in this work. Additionally, the experimental results are compared with the estimations obtained by applying the group contribution model of UNIFAC, in the versions of Larsen et al. (1987) [16] and Gmehling et al. (1993) [17]. Several empirical expressions for estimating ternary properties from binary results were also tested

  12. Discovery, synthesis, selectivity modulation and DMPK characterization of 5-azaspiro[2.4]heptanes as potent orexin receptor antagonists.

    Stasi, Luigi Piero; Artusi, Roberto; Bovino, Clara; Buzzi, Benedetta; Canciani, Luca; Caselli, Gianfranco; Colace, Fabrizio; Garofalo, Paolo; Giambuzzi, Silvia; Larger, Patrice; Letari, Ornella; Mandelli, Stefano; Perugini, Lorenzo; Pucci, Sabrina; Salvi, Matteo; Toro, PierLuigi

    2013-05-01

    Starting from a orexin 1 receptor selective antagonist 4,4-disubstituted piperidine series a novel potent 5-azaspiro[2.4]heptane dual orexin 1 and orexin 2 receptor antagonist class has been discovered. SAR and Pharmacokinetic optimization of this series is herein disclosed. Lead compound 15 exhibits potent activity against orexin 1 and orexin 2 receptors along with low cytochrome P450 inhibition potential, good brain penetration and oral bioavailability in rats. Copyright © 2013 Elsevier Ltd. All rights reserved.

  13. Combustion characteristics and influential factors of isooctane active-thermal atmosphere combustion assisted by two-stage reaction of n-heptane

    Lu, Xingcai; Ji, Libin; Ma, Junjun; Zhou, Xiaoxin; Huang, Zhen [Key Lab. for Power Machinery and Engineering of MOE, Shanghai Jiao Tong University, 200240 Shanghai (China)

    2011-02-15

    This paper presents an experimental study on the isooctane active-thermal atmosphere combustion (ATAC) which is assisted by two-stage reaction of n-heptane. The active-thermal atmosphere is created by low- and high-temperature reactions of n-heptane which is injected at intake port, and isooctane is directly injected into combustion chamber near the top dead center. The effects of isooctane injection timing, active-thermal atmosphere intensity, overall equivalence ratio, and premixed ratio on combustion characteristics and emissions are investigated. The experimental results reveal that, the isooctane ignition and combustion can be classified to thermal atmosphere combustion, active atmosphere combustion, and active-thermal atmosphere combustion respectively according to the extent of n-heptane oxidation as well as effects of isooctane quenching and charge cooling. n-Heptane equivalence ratio, isooctane equivalence ratio and isooctane delivery advance angle are major control parameters. In one combustion cycle, the isooctane ignited and burned after those of n-heptane, and then this combustion phenomenon can also be named as dual-fuel sequential combustion (DFSC). The ignition timing of the overall combustion event is mainly determined by n-heptane equivalence ratio and can be controlled in flexibility by simultaneously adjusting isooctane equivalence ratio. The isooctane ignition regime, overall thermal efficiency, and NO{sub x} emissions show strong sensitivity to the fuel delivery advance angle between 20 CA BTDC and 25 CA BTDC. (author)

  14. Hydroperoxide Measurements During Low-Temperature Gas-Phase Oxidation of n-Heptane and n-Decane

    Rodriguez, Anne

    2017-02-13

    A wide range of hydroperoxides (C-C alkyl hydroperoxides, C-C alkenyl hydroperoxides, C ketohydroperoxides, and hydrogen peroxide (HO)), as well as ketene and diones, have been quantified during the gas-phase oxidation of n-heptane. Some of these species, as well as C alkenyl hydroperoxides and ketohydroperoxides, were also measured during the oxidation of n-decane. These experiments were performed using an atmospheric-pressure jet-stirred reactor at temperatures from 500 to 1100 K and one of three analytical methods, time-of-flight mass spectrometry combined with tunable synchrotron photoionization with a molecular beam sampling: time-of-flight mass spectrometry combined with laser photoionization with a capillary tube sampling, continuous wave cavity ring-down spectroscopy with sonic probe sampling. The experimental temperature at which the maximum mole fraction is observed increases significantly for alkyl hydroperoxides, alkenyl hydroperoxides, and then more so again for hydrogen peroxide, compared to ketohydroperoxides. The influence of the equivalence ratio from 0.25 to 4 on the formation of these peroxides has been studied during n-heptane oxidation. The up-to-date detailed kinetic oxidation models for n-heptane and for n-decane found in the literature have been used to discuss the possible pathways by which these peroxides, ketene, and diones are formed. In general, the model predicts well the reactivity of the two fuels, as well as the formation of major intermediates. (Figure Presented).

  15. Hydroperoxide Measurements During Low-Temperature Gas-Phase Oxidation of n-Heptane and n-Decane

    Rodriguez, Anne; Herbinet, Olivier; Meng, Xiangzan; Fittschen, Christa; Wang, Zhandong; Xing, Lili; Zhang, Lidong; Battin-Leclerc, Fré dé rique

    2017-01-01

    A wide range of hydroperoxides (C-C alkyl hydroperoxides, C-C alkenyl hydroperoxides, C ketohydroperoxides, and hydrogen peroxide (HO)), as well as ketene and diones, have been quantified during the gas-phase oxidation of n-heptane. Some of these species, as well as C alkenyl hydroperoxides and ketohydroperoxides, were also measured during the oxidation of n-decane. These experiments were performed using an atmospheric-pressure jet-stirred reactor at temperatures from 500 to 1100 K and one of three analytical methods, time-of-flight mass spectrometry combined with tunable synchrotron photoionization with a molecular beam sampling: time-of-flight mass spectrometry combined with laser photoionization with a capillary tube sampling, continuous wave cavity ring-down spectroscopy with sonic probe sampling. The experimental temperature at which the maximum mole fraction is observed increases significantly for alkyl hydroperoxides, alkenyl hydroperoxides, and then more so again for hydrogen peroxide, compared to ketohydroperoxides. The influence of the equivalence ratio from 0.25 to 4 on the formation of these peroxides has been studied during n-heptane oxidation. The up-to-date detailed kinetic oxidation models for n-heptane and for n-decane found in the literature have been used to discuss the possible pathways by which these peroxides, ketene, and diones are formed. In general, the model predicts well the reactivity of the two fuels, as well as the formation of major intermediates. (Figure Presented).

  16. Experimental and numerical analysis of the performance and exhaust gas emissions of a biogas/n-heptane fueled HCCI engine

    Kozarac, Darko; Taritas, Ivan; Vuilleumier, David; Saxena, Samveg; Dibble, Robert W.

    2016-01-01

    The use of highly reactive fuel as an ignition promoter enables operation of biogas fueled homogeneous charge compression ignition (HCCI) engine at low intake temperatures with practical control of combustion phasing. In order to gain some insight into this operation mode the influence of addition of n-heptane on combustion, performance, emissions and control of combustion phasing of a biogas fueled HCCI engine is experimentally researched and presented in this paper. Additionally, the performance analysis of the practical engine solution for such operation is estimated by using the numerical simulation of entire engine. The results showed that the introduction of highly reactive fuel results with a significant change in operating conditions and with a change in optimum combustion phasing. The addition of n-heptane resulted in lower nitrogen oxides and increased carbon monoxide emissions, while the unburned hydrocarbons emissions were strongly influenced by combustion phasing and at optimal conditions are lowered compared to pure biogas operation. The results also showed a practical operation range for strategies that use equivalence ratio as a control of load. Simulation results showed that the difference in performance between pure biogas and n-heptane/biogas operation is even greater when the practical engine solution is taken into account.

  17. Experimental and numerical analysis of the performance and exhaust gas emissions of a biogas/n-heptane fueled HCCI engine

    Kozarac, Darko

    2016-09-12

    The use of highly reactive fuel as an ignition promoter enables operation of biogas fueled homogeneous charge compression ignition (HCCI) engine at low intake temperatures with practical control of combustion phasing. In order to gain some insight into this operation mode the influence of addition of n-heptane on combustion, performance, emissions and control of combustion phasing of a biogas fueled HCCI engine is experimentally researched and presented in this paper. Additionally, the performance analysis of the practical engine solution for such operation is estimated by using the numerical simulation of entire engine. The results showed that the introduction of highly reactive fuel results with a significant change in operating conditions and with a change in optimum combustion phasing. The addition of n-heptane resulted in lower nitrogen oxides and increased carbon monoxide emissions, while the unburned hydrocarbons emissions were strongly influenced by combustion phasing and at optimal conditions are lowered compared to pure biogas operation. The results also showed a practical operation range for strategies that use equivalence ratio as a control of load. Simulation results showed that the difference in performance between pure biogas and n-heptane/biogas operation is even greater when the practical engine solution is taken into account.

  18. DNS Study of the Ignition of n-Heptane Fuel Spray under HCCI Conditions

    Wang, Yunliang; Rutland, Christopher J.

    2004-11-01

    Direct numerical simulations are carried out to investigate the mixing and auto-ignition processes of n-heptane fuel spray in a turbulent field using a skeletal chemistry mechanism with 44 species and 112 reactions. For the solution of the carrier gas fluid, we use the Eulerian method, while for the fuel spray, the Lagrangian method is used. We use an eighth-order finite difference scheme to calculate spacial derivatives and a fourth-order Runge-Kutta scheme for the time integration. The initial gas temperature is 926 K and the initial gas pressure is 30 atmospheres. The initial global equivalence ratio based on the fuel concentration is around 0.4. The initial droplet diameter is 60 macrons and the droplet temperature is 300 K. Evolutions of averaged temperature, species mass fraction, heat release and reaction rate are presented. Contours of temperature and species mass fractions are presented. The objective is to understand the mechanism of ignition under Homogeneous Charged Compression Ignition (HCCI) conditions, aiming at providing some useful information of HCCI combustion, which is one of the critical issues to be resolved.

  19. Stabilization and structure of n-heptane tribrachial flames in axisymmetric laminar jets

    Bisetti, Fabrizio

    2015-01-01

    A set of tribrachial flames of n-heptane/air is simulated with finite rate chemistry and detailed transport in a realistic laminar jet configuration for which experimental data are available. The flames differ by the temperature of the unburnt mixture and stabilization height, which controls the mixture fraction gradient ahead of the flame front. The simulations reproduce the lift-off heights in the experiments, showing that the flame stabilizes further downstream as the unburnt temperature decreases. For the lowest unburnt temperature, resulting in a weak mixture fraction gradient at the tribrachial point, positive stretch along the rich premixed wing leads to an increase in the rate of chemical reaction in the whole flame. The tribrachial flame burning velocity exceeds that in the unstretched, one-dimensional flame. For the highest temperature, the flame stabilizes closest to the nozzle. Large flame tilt, large mixture fraction gradient, and small radius of curvature lead to a reduction in the heat release rate and the flame propagates slower than its one-dimensional counterpart. The observed behavior is explained with a detailed analysis of the flame geometry, differential diffusion effects, flame stretch, and transport of heat and mass from the burnt gases to the flame front. © 2014 The Combustion Institute.

  20. Characterization of n-heptane as a single component Diesel surrogate fuel. EHPC test set-up implementation

    Meijer, M.

    2010-06-15

    The availability of accurately measured fuel properties, during an injection event under engine relevant conditions is critical within the surrogate fuel approach. There is a need to perform in-house measurements in order to validate developed and new models. A well defined and accurately measured data-set will facilitate on-going work for sophisticated engine related in-cylinder combustion modeling. In this work pure n-heptane fuel is used as a single component surrogate fuel and is studied in a high-pressure constant volume optical test set-up. N-heptane is often used as a single component surrogate diesel fuel since it has a comparable Cetane number as European diesel. Detailed chemical-kinetic mechanisms for low-, intermediate-, and high-temperature n-heptane oxidation are available and several models exist that have sufficiently reduced dimensionality (number of species and reactions) to enable their use in CFD (Computational Fluid Mechanics) simulations. This report discusses the route and implementation to perform such an accurate and relevant n-heptane measurement series. The aim is to combine the efforts of earlier presented EHPC (Eindhoven High Pressure Cell) related work and new approaches, into the proposed surrogate fuel measurement series. The following aspects, related to the applied constant volume combustion chamber set-up, are studied and implemented: Extending the operating ranges towards relevant engine conditions; Study the accuracy and sensitivities of the different measurement steps; Implementing different optical diagnostic principles; and Implement a standardized and robust post processing routine. The different optical diagnostic principles used in this work are: high-speed Schlieren, Mie scattering and beginnings are made to implement a simultaneous LII LIF (Laser Induced Incandescence - Laser Induced Fluorescence) set-up using a new ICCD (Intensified Charge Coupled Device) camera with dual imaging feature. Combining the different

  1. Thermodynamic study of (heptane + amine) mixtures. III: Excess and partial molar volumes in mixtures with secondary, tertiary, and cyclic amines at 298.15 K

    Lepori, Luciano; Gianni, Paolo; Spanedda, Andrea; Matteoli, Enrico

    2011-01-01

    Graphical abstract: Highlights: → Excess volumes of (sec., tert., or cyclic amines + heptane) mixtures. → Excess volumes are positive for small size amines and decrease as the size increases. → Group contributions to predict the partial molar volumes of amines in heptane. → The void volume is larger for sec. and tert. than for linear amines in heptane. → The void volume is much smaller for cyclic than for linear amines in heptane. - Abstract: Excess molar volumes V E at 298.15 K were determined by means of a vibrating tube densimeter for binary mixtures of {heptane + open chain secondary (diethyl to dibutyl) and tertiary (triethyl to tripentyl) amines} as well as for cyclic imines (C 2 , C 3 , C 4 , C 6 , and C 7 ) and primary cycloalkylamines (C 5 , C 6 , C 7 , and C 12 ). The V E values were found positive for mixtures involving small size amines, with V E decreasing as the size increases. Negative V E 's were found for tributyl- and tripentylamine, heptamethylenimine, and cyclododecylamine. Mixtures of heptane with cycloheptylamine showed an s-shaped curve. Partial molar volumes V 0 of amines at infinite dilution in heptane were obtained from V E and compared with V 0 of hydrocarbons and other classes of organic compounds taken from literature. An additivity scheme, based on the intrinsic volume approach, was applied to estimate group (CH 3 , CH 2 , CH, C, NH 2 , NH, N, OH, O, CO, and COO) contributions to V 0 . These contributions, the effect of cyclization on V 0 , and the limiting slope of the apparent excess molar volumes were discussed in terms of solute-solvent and solute-solute interactions.

  2. A Model of Reduced Kinetics for Alkane Oxidation Using Constituents and Species for N-Heptane

    Harstad, Kenneth G.; Bellan, Josette

    2011-01-01

    The reduction of elementary or skeletal oxidation kinetics to a subgroup of tractable reactions for inclusion in turbulent combustion codes has been the subject of numerous studies. The skeletal mechanism is obtained from the elementary mechanism by removing from it reactions that are considered negligible for the intent of the specific study considered. As of now, there are many chemical reduction methodologies. A methodology for deriving a reduced kinetic mechanism for alkane oxidation is described and applied to n-heptane. The model is based on partitioning the species of the skeletal kinetic mechanism into lights, defined as those having a carbon number smaller than 3, and heavies, which are the complement of the species ensemble. For modeling purposes, the heavy species are mathematically decomposed into constituents, which are similar but not identical to groups in the group additivity theory. From analysis of the LLNL (Lawrence Livermore National Laboratory) skeletal mechanism in conjunction with CHEMKIN II, it is shown that a similarity variable can be formed such that the appropriately non-dimensionalized global constituent molar density exhibits a self-similar behavior over a very wide range of equivalence ratios, initial pressures and initial temperatures that is of interest for predicting n-heptane oxidation. Furthermore, the oxygen and water molar densities are shown to display a quasi-linear behavior with respect to the similarity variable. The light species ensemble is partitioned into quasi-steady and unsteady species. The reduced model is based on concepts consistent with those of Large Eddy Simulation (LES) in which functional forms are used to replace the small scales eliminated through filtering of the governing equations; in LES, these small scales are unimportant as far as the overwhelming part of dynamic energy is concerned. Here, the scales thought unimportant for recovering the thermodynamic energy are removed. The concept is tested by

  3. (Liquid + liquid) equilibrium for the ternary systems {heptane + toluene + 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide} and {heptane + toluene + 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide} ionic liquids

    Garcia, Silvia; Larriba, Marcos; Garcia, Julian; Torrecilla, Jose S.; Rodriguez, Francisco

    2011-01-01

    Highlights: → Values of D 1 and D 2 for [mpim][Tf 2 N] are higher than those for [amim][Tf 2 N]. → Values of α 2,1 for [mpim][Tf 2 N] are lower than those for [amim][Tf 2 N]. → Values of D 2 for both ionic liquids are higher than those for sulfolane. → Values of α 2,1 for [mpim][Tf 2 N] are lower than those for sulfolane at x 2 I 2 N] could be considered as an alternative solvent to sulfolane. - Abstract: The (liquid + liquid) equilibrium (LLE) data for two systems containing heptane, toluene, and 1-methyl-3-propylimidazolium bis(trifluoromethylsulfonyl)imide ([mpim][Tf 2 N]) or 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([amim][Tf 2 N]) ionic liquids (ILs) were determined at T = 313.2 K and atmospheric pressure. The effect of a double bond in an alkyl side chain in the imidazolium cation was evaluated in terms of selectivity and extractive capacity. The results show a decrease of the amount of toluene and heptane dissolved in the IL with the allyl group. Thus, the distribution ratios of toluene and heptane of [mpim][Tf 2 N] IL are higher than those of [amim][Tf 2 N] IL. On the other hand, the separation factor of the [amim][Tf 2 N] IL increases comparing to [mpim][Tf 2 N] IL. The NRTL model was used to correlate satisfactorily the experimental LLE data for the two studied ternary systems.

  4. Synthesis of Carbon–Metal Multi-Strand Nanocomposites by Discharges in Heptane Between Two Metallic Electrodes

    Hamdan, Ahmad

    2017-04-26

    We studied composite wires assembled from electric field-driven nanoparticles in a dielectric liquid (heptane) to elucidate the exact processes and controlling factors involved in the synthesis of the multi-phase nanocomposites. Filamentary wires are synthesized by a two-step process: (1) abundant nanoparticle production, mostly of carbonaceous types, from heptane decomposition by spark discharge and of metal nanoparticles by electrode erosion and (2) assembly of hydrogenated amorphous carbonaceous nano-clusters with incorporated metal nanoparticles forming wires by dielectrophoretic transport while maintaining a high electric field between electrodes kept sufficiently separated to avoid breakdown. Four types of nanocomposites products are identified to form at different steps in distinctive zones of the setup. The black carbonaceous agglomerates with metal spherules made by electrode erosion represent the pyrolytic residues of heptane decomposition by spark discharge during step 1. The filamentary wires grown in the interelectrode gap during step 2 get assembled by dielectrophoretic transport and chaining forces. Their great stability is shown to express the concurrent effect of polymerization favoured by the abundance of metal catalysts. The nature, abundance, and transformation of solid particles from the source materials versus discharge conditions control the morphological and compositional diversity of the wires. The production of mineral and metal nano-particles traces the efficiency of dielectrophoresis to separate compound particle mixtures by size and to co-synthesize nanostructured microcrystals and nanocomposites. The link between impurities and the variability from nano- to micro-scales of the synthesized products provides an innovative contribution to the knowledge of nanocomposite synthesis triggered by electric field.

  5. Analysis of lift-off height and structure of n-heptane tribrachial flames in laminar jet configuration

    Luca, Stefano; Bisetti, Fabrizio

    2015-01-01

    A set of lifted tribrachial n-heptane flames in a laminar jet configuration are simulated. The simulations are performed using finite rate chemistry and detailed transport, and aim at investigating the propagation of tribrachial flames. Varying the inlet velocity of the fuel, different stabilization heights are obtained, and the dependence of the stabilization height in the inlet velocity is compared with experimental data. A detailed analysis of the flame geometry is performed by comparingthe flame structure to that of unstretched premixed flames. Issues related to differential diffusion effects, flame stretch, and transport of heat and mass from the burnt gases to the flame front are discussed.

  6. New Methyltrimethoxysilane-(3-Mercaptopropyl)- Trimethoxysilane Coated Hollow Fiber-Solid Phase Micro extraction for Hexanal and Heptanal Analysis

    Siti Munirah Abd Wahib; Mohd Marsin Sanagi

    2016-01-01

    Determination of volatile organic compounds (VOCs) in various matrices is often accomplished using solid phase micro extraction (SPME) as a superior mode of extraction. Alternatively, another configuration of solid phase micro extraction (SPME) namely hollow fiber-solid phase micro extraction (HF-SPME) is a great approach to redress some limitations of the ordinary SPME fibers including fiber breakage, coating stripping and sample carry over. The HF-SPME technique highlights the use of hollow polypropylene (PP) membrane to hold and protect the adsorbent inside its lumen. Unlike the conventional SPME, the inexpensive HF device can be disposed after single use. Introducing extracting phase via sol-gel technology has gained great interest owing to its simple preparation method and promising way to obtain materials with good characteristics. In the present work, a new hybrid silica material based on methyltrimethoxysilane-(3-mercaptopropyl)trimethoxysilane (MTMOS-MPTMOS) was introduced as a new extractant of HF-SPME and the effectiveness of the proposed method was tested for analysis of hexanal and heptanal as the target VOC analytes. Preparation of the HF-SPME MTMOS-MPTMOS was simple in which the hybrid material was synthesized via sol-gel method and was self-polymerized in small segments of HF. Parameters affecting the efficiency of the HF-SPME MTMOS-MPTMOS in extracting both aldehydes were thoroughly investigated and analyzed by gas chromatography-flame ionization detection (GC-FID). It was found that the highest efficiency was achieved as the extraction was conducted in 30 min at a stirring rate of 1000 rpm in a 10 mL of sample solution whereby the back-extraction was performed via vortex for 3 min using 100 μL methanol as desorption solvent. Under the optimal conditions, linearity was observed over a range of 0.020-10.00 μg mL"-"1 with detection limits of 0.015 μg mL"-"1 and 0.010 μg mL"-"1 for hexanal and heptanal, respectively. The applicability of the HF

  7. n-Heptane cool flame chemistry: Unraveling intermediate species measured in a stirred reactor and motored engine

    Wang, Zhandong

    2017-10-03

    This work identifies classes of cool flame intermediates from n-heptane low-temperature oxidation in a jet-stirred reactor (JSR) and a motored cooperative fuel research (CFR) engine. The sampled species from the JSR oxidation of a mixture of n-heptane/O2/Ar (0.01/0.11/0.88) were analyzed using a synchrotron vacuum ultraviolet radiation photoionization (SVUV-PI) time-of-flight molecular-beam mass spectrometer (MBMS) and an atmospheric pressure chemical ionization (APCI) Orbitrap mass spectrometer (OTMS). The OTMS was also used to analyze the sampled species from a CFR engine exhaust. Approximately 70 intermediates were detected by the SVUV-PI-MBMS, and their assigned molecular formulae are in good agreement with those detected by the APCI-OTMS, which has ultra-high mass resolving power and provides an accurate elemental C/H/O composition of the intermediate species. Furthermore, the results show that the species formed during the partial oxidation of n-heptane in the CFR engine are very similar to those produced in an ideal reactor, i.e., a JSR.The products can be classified by species with molecular formulae of C7H14Ox (x = 0–5), C7H12Ox (x = 0–4), C7H10Ox (x = 0–4), CnH2n (n = 2–6), CnH2n−2 (n = 4–6), CnH2n+2O (n = 1–4), CnH2nO (n = 1–6), CnH2n−2O (n = 2–6), CnH2n−4O (n = 4–6), CnH2n+2O2 (n = 0–4, 7), CnH2nO2 (n = 1–6), CnH2n−2O2 (n = 2–6), CnH2n−4O2 (n = 4–6), and CnH2nO3 (n = 3–6). The identified intermediate species include alkenes, dienes, aldehyde/keto compounds, olefinic aldehyde/keto compounds, diones, cyclic ethers, peroxides, acids, and alcohols/ethers. Reaction pathways forming these intermediates are proposed and discussed herein. These experimental results are important in the development of more accurate kinetic models for n-heptane and longer-chain alkanes.

  8. Dielectric Properties of Water in Butter and Water-AOT-Heptane Systems Measured using Terahertz Time-Domain Spectroscopy

    Møller, Uffe; Folkenberg, Jacob Riis; Jepsen, Peter Uhd

    2010-01-01

    We investigate the dielectric properties of water confined in nanometer-sized inverse micelles in mixtures of water, AOT, and heptane. We show that the dielectric properties of the confined water are dependent on the water pool size and different from those of bulk water. We also discuss...... the dielectric properties of different vegetable oils, lard, and butter, and use these properties to deduce the dielectric properties of water in butter, which are shown to deviate significantly from the dielectric properties of bulk water....

  9. Analysis of lift-off height and structure of n-heptane tribrachial flames in laminar jet configuration

    Luca, Stefano

    2015-03-30

    A set of lifted tribrachial n-heptane flames in a laminar jet configuration are simulated. The simulations are performed using finite rate chemistry and detailed transport, and aim at investigating the propagation of tribrachial flames. Varying the inlet velocity of the fuel, different stabilization heights are obtained, and the dependence of the stabilization height in the inlet velocity is compared with experimental data. A detailed analysis of the flame geometry is performed by comparingthe flame structure to that of unstretched premixed flames. Issues related to differential diffusion effects, flame stretch, and transport of heat and mass from the burnt gases to the flame front are discussed.

  10. Analysis on reduced chemical kinetic model of N-heptane for HCCI combustion. Paper no. IGEC-1-072

    Yao, M.; Zheng, Z.

    2005-01-01

    Because of high complexity coupled with multidimensional fluid dynamics, it is difficult to apply detailed chemical kinetic model to simulate practical engines. A reduced model of n-heptane has been developed on the basic of detailed mechanism by sensitivity analysis and reaction path analysis of every stage of combustion. The new reduced mechanism consists of 35 species and 41 reactions, and it is effective in engine condition. The results show that it gives predictions similar to the detailed model in ignition timing, in-cylinder temperature and pressure. Furthermore, the reduced mechanism can be used to simulate boundary condition of partial combustion in good agreement with the detailed mechanism. (author)

  11. Combustion Characteristics in a Non-Premixed Cool-Flame Regime of n-Heptane in Microgravity

    Takahashi, Fumiaki; Katta, Viswanath R.; Hicks, Michael C.

    2015-01-01

    A series of distinct phenomena have recently been observed in single-fuel-droplet combustion tests performed on the International Space Station (ISS). This study attempts to simulate the observed flame behavior numerically using a gaseous n-heptane fuel source in zero gravity and a time-dependent axisymmetric (2D) code, which includes a detailed reaction mechanism (127 species and 1130 reactions), diffusive transport, and a radiation model (for CH4, CO, CO2, H2O, and soot). The calculated combustion characteristics depend strongly on the air velocity around the fuel source. In a near-quiescent air environment (combustion experiments.

  12. Ignition of turbulent swirling n-heptane spray flames using single and multiple sparks

    Marchionea, T.; Ahmeda, S.F.; Mastorakos, E. [Department of Engineering, University of Cambridge (United Kingdom)

    2009-01-15

    This paper examines ignition processes of an n-heptane spray in a flow typical of a liquid-fuelled burner. The spray is created by a hollow-cone pressure atomiser placed in the centre of a bluff body, around which swirling air induces a strong recirculation zone. Ignition was achieved by single small sparks of short duration (2 mm; 0.5 ms), located at various places inside the flow so as to identify the most ignitable regions, or larger sparks of longer duration (5 mm; 8 ms) repeated at 100 Hz, located close to the combustion chamber enclosure so as to mimic the placement and characteristics of a gas turbine combustor surface igniter. The air and droplet velocities, the droplet diameter, and the total (i.e. liquid plus vapour) equivalence ratio were measured in inert flow by phase Doppler anemometry and sampling respectively. Fast camera imaging suggested that successful ignition events were associated with flamelets that propagated back towards the spray nozzle. Measurements of ignition probability with the single spark showed that localised ignition inside the spray is more likely to result in successful flame establishment when the spark is located in a region of negative velocity, relatively small droplet Sauter mean diameter, and mean equivalence ratio within the flammability limits. Ignition with the single spark was not possible at the location where the multiple spark experiments were performed. For those, the multiple spark sequence lasted approximately 1 to 5 s. It was found that a long spark sequence increases the ignition efficiency, which reached a maximum of 100% at the axial distance where the recirculation zone had maximum width. Ignition was not feasible with the spark downstream of about two burner diameters. Visualisation showed that small flame kernels emanate very often from the spark, which can be stretched as far as 20 mm from the electrodes by the turbulent velocity fluctuations. These kernels survive very little time. Successful overall

  13. [Optimizing synthesis of conjugates of superoxide dismutase and catalase with aldehyde dextrans in surfactant microemulsions in heptane].

    Eremin, A N; Metelitsa, D I

    1997-01-01

    Stable microemulsions in heptane retaining considerable amounts of the polar phase were obtained by using Aerosol OT (AOT), Triton X-45, and catalase. Conjugates of superoxide dismutase (SOD) and catalase with aldehyde dextrans (AD) were synthesized in surfactant microemulsions in heptane. Effects of the reaction duration, the microemulsion polar phase volume, and concentrations of enzymes and modifiers on the properties of these conjugates were studied. The catalytic properties of conjugates depended on the nature of the surfactants used to stabilize the microemulsions, the initial concentration of protein in the reaction mixture, and the enzyme: modifier ratio. The degree of modification of the enzymes and the stabilities of their conjugates during isolation from microemulsions by a water-acetone solution depended on the concentration of the AD used. The catalytic properties of the conjugates synthesized were compared, and their stabilities in the presence of H2O2 were described. We suggested a simple method of transformation of whole kinetic curves of H2O2 conversion in coordinates 1/ln([H2O2]0/[H2O2]t - 1/t for simultaneous measurement of the constant of the catalase inactivation rate by H2O2 (Cin, S-1) and the rate constant of the catalase complex 1 interaction with the second H2O2 molecule (C2, M-1 S-1). This method was tested experimentally. Values C2 and Cin for catalase and its conjugates with ADs were compared, and these results were discussed.

  14. New carbocyclic nucleoside analogues with a bicyclo[2.2.1]heptane fragment as sugar moiety; synthesis, X-ray crystallography and anticancer activity.

    Tănase, Constantin I; Drăghici, Constantin; Căproiu, Miron Teodor; Shova, Sergiu; Mathe, Christophe; Cocu, Florea G; Enache, Cristian; Maganu, Maria

    2014-01-01

    An amine group was synthesized starting from an optically active bicyclo[2.2.1]heptane compound, which was then used to build the 5 atoms ring of a key 6-chloropurine intermediate. This was then reacted with ammonia and selected amines obtaining new adenine- and 6-substituted adenine conformationally constrained carbocyclic nucleoside analogues with a bicyclo[2.2.1]heptane skeleton in the sugar moiety. X-ray crystallography confirmed an exo-coupling of base to the ring and a L configuration of the nucleoside analogues. The compounds were tested for anticancer activity. Copyright © 2013 Elsevier Ltd. All rights reserved.

  15. Stabilization and structure of N-heptane flame on CWJ-spray burner with kHZ SPIV and OH-PLIF

    Mansour, Morkous S.; Al Khesho, Issam; Chung, Suk-Ho

    2015-01-01

    characteristics and structure of n-heptane/air turbulent flames were investigated with varying fuel and air flow rates and the position of pressure atomizer (L). High-speed planar laser-induced fluorescence (PLIF) of OH radicals delineated reaction zone contours

  16. Autoignition characterization of primary reference fuels and n-heptane/n-butanol mixtures in a constant volume combustion device and homogeneous charge compression ignition engine

    Baumgardner, Marc E.; Sarathy, Mani; Má rchese, Anthony J.

    2013-01-01

    -octane, n-heptane, and n-butanol were tested in the FIT - 28 test runs with 25 ignition measurements for each test run, totaling 350 individual tests in all. These experimental results supported previous findings that fuel blends with high alcohol content

  17. Experimental and theoretical study of surface tension of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene)

    Rafati, Amir Abbas; Ghasemian, Ensieh

    2009-01-01

    Surface properties of binary mixtures of (n-alkyl acetates + heptane, benzene, and toluene) have been measured by surface tension method at T = 298.15 K and atmospheric pressure. Also, the surface tension has been predicted based on the Suarez method. This method combines a model for the description of surface tension of liquid mixtures with a group contribution method for the calculation of activity coefficient. The mean relative standard deviations obtained from the comparison of experimental (measured) and calculated surface tension values for the eight binary systems are less than 1.5%, which leads to concluding that the model shows a good accuracy in different situations in comparison with other predicted equations. In addition, the relative Gibbs adsorption and the surface mole fraction have been evaluated using this model. The surface tension deviations were calculated from experimental results and have been fitted to the Redlich-Kister type polynomial relation

  18. Catalytic properties and acidity of modified MCM-41 mesoporous materials with low Si/Al ratio: heptane isomerisation

    Ahmed Belhakem

    2006-06-01

    Full Text Available The catalytic properties and acidity of modified MCM-41 with a low Si/Al ratio and 0-95% NH4+ exchange were investigated. The samples were characterised by X-ray diffraction, scanning and transmission electron microscopy, and nitrogen adsorption. The acidity was studied by pyridine adsorption, temperature programmed desorption (TPD of ammonia, and infrared (IR spectroscopy. Adsorption of pyridine and IR spectroscopy indicated various types of Lewis and Brönsted acid sites. The density distribution of acid sites was determined by TPD. Both Lewis and Brönsted acid sites were found to be active in the heptane isomerisation. The presence of aluminium (low Si/Al combined to the ionic exchange between Na+ and NH4+ increases the acidity of MCM-41 materials. A close correlation between acidity and isomerisation was observed. Coke deposition, which reduces the activity, was also studied.

  19. NOx formation from the combustion of monodisperse n-heptane sprays doped with fuel-nitrogen additives

    Sarv, Hamid; Cernansky, Nicholas P.

    1989-01-01

    A series of experiments with simulated synthetic fuels were conducted in order to investigate the effect of droplet size on the conversion of fuel-nitrogen to NOx. Pyridine and pyrrole were added to n-heptane as nitrogen-containing additives and burned as monodisperse fuel droplets under various operating conditions in a spray combustion facility. The experimental results indicate that under stoichiometric and fuel-rich conditions, reducing the droplet size increases the efficiency of fuel-N conversion to NOx. This observation is associated with improved oxidation of the pyrolysis fragments of the additive by better oxygen penetration through the droplet flame zone. The dominant reactions by which fuel-N is transformed to NOx were also considered analytically by a premixed laminar flame code. The calculations are compared to the small droplet size results.

  20. Autoignited and non-autoignited lifted flames of pre-vaporized n-heptane in coflow jets at elevated temperatures

    Choi, Sangkyu

    2013-09-01

    The characteristics of laminar lifted flames of pre-vaporized n-heptane in coflow jets were investigated under both non-autoignited and autoignited conditions by varying the initial temperature. The fuel tested was n-heptane considering the importance as a primary reference fuel for gasoline and its low temperature ignition behavior at relatively low pressure. The results showed that the lifted flame edge in the non-autoignited regime had a tribrachial structure with lean and rich premixed flame wings together with a trailing diffusion flame. The liftoff heights correlated reasonably well with the fuel jet velocity scaled by the stoichiometric laminar burning velocity regardless of the initial temperature and the nitrogen dilution. The liftoff velocity multiplied by the buoyancy-induced velocity and the blowout velocity scaled by the mole fraction of the fuel correlated well with the stoichiometric laminar burning velocity. When the initial temperature was above 900. K, flames were autoignited without any external ignition source. Autoignited lifted flames with both tribrachial edges and mild combustion characteristics were observed. The correlation of the liftoff height with the calculated adiabatic ignition delay time was weak, unlike in cases with gaseous fuels of C1-C4 hydrocarbons in which the liftoff height of the autoignited flames correlated well with the square of the adiabatic ignition delay time. When the mole fraction of the fuel was small, mild combustion behaviors were exhibited with edge flames without distinct tribrachial structures. The liftoff height was correlated with the fuel jet velocity scaled by the initial fuel mass fraction, while the dependence on the ignition delay time was weak when compared with the gaseous fuels. © 2013 The Combustion Institute.

  1. A comprehensive skeletal mechanism for the oxidation of n-heptane generated by chemistry-guided reduction

    Zeuch, Thomas [Institut fuer Physikalische Chemie, Tammannstrasse 6, 37077 Goettingen (Germany); Moreac, Gladys [Renault, 1, avenue du Golf, 78288 Guyancourt cedex (France); Ahmed, Syed Sayeed; Mauss, Fabian [Lehrstuhl fuer Thermodynamik und Thermische Verfahrenstechnik, Sielower Strasse 12, 03044 Cottbus (Germany)

    2008-12-15

    Applied to the primary reference fuel n-heptane, we present the chemistry-guided reduction (CGR) formalism for generating kinetic hydrocarbon oxidation models. The approach is based on chemical lumping and species removal with the necessity analysis method, a combined reaction flow and sensitivity analysis. Independent of the fuel size, the CGR formalism generates very compact submodels for the alkane low-temperature oxidation and provides a general concept for the development of compact oxidation models for large model fuel components such as n-decane and n-tetradecane. A defined sequence of simplification steps, consisting of the compilation of a compact detailed chemical model, the application of linear chemical lumping, and finally species removal based on species necessity values, allows a significantly increased degree of reduction compared to the simple application of the necessity analysis, previously published species, or reaction removal methods. The skeletal model derived by this procedure consists of 110 species and 1170 forward and backward reactions and is validated against the full range of combustion conditions including low and high temperatures, fuel-lean and fuel-rich mixtures, pressures between 1 and 40 bar, and local (species concentration profiles in flames, plug flow and jet-stirred reactors, and reaction sensitivity coefficients) and global parameters (ignition delay times in shock tube experiments, ignition timing in a HCCI engine, and flame speeds). The species removal is based on calculations using a minimum number of parameter configurations, but complemented by a very broad parameter variation in the process of compiling the kinetic input data. We further demonstrate that the inclusion of sensitivity coefficients in the validation process allows efficient control of the reduction process. Additionally, a compact high-temperature n-heptane oxidation model of 47 species and 468 reactions was generated by the application of necessity

  2. Study on the knock tendency and cyclical variations of a HCCI engine fueled with n-butanol/n-heptane blends

    Li, Gang; Zhang, Chunhua; Zhou, Jiawang

    2017-01-01

    Highlights: • The HCCI combustion was achieved on an engine fueled by n-butanol/n-heptane blends. • The knock tendency and cyclical variation of the HCCI combustion were studied. • The knock tendency can be weakened by increasing the blending ratio of n-butanol. • The knock tendency and cyclical variation are sensitive to the combustion phasing. • Cyclical variation always shows an opposite trend with the knock tendency. - Abstract: The homogeneous charge compression ignition (HCCI) combustion operation is conducted in the 2nd cylinder of a natural-aspirated four-stroke diesel engine. In the HCCI combustion mode, the n-butanol, n-heptane and their blends are injected into the intake port to form a lean homogeneous air-fuel mixture, which is consumed by the autoignition after compression. The objective of this study is to investigate the knock tendency and the cyclical variations of the HCCI engine. Experimental results show that the volume fraction of n-butanol affects the knock tendency greatly, which obviously decreases as the n-butanol volume fraction increases. The knocking combustion in the HCCI combustion is characterized by the high heat release rate (HRR). Both elevating the engine speed and raising the intake temperature contributes to an obvious increase in HRR and the knock tendency. But the HRR and knock tendency may slightly decrease when the engine speed reaches to 1400 rev/min and intake temperature reaches to 160 °C. Furthermore, the knock tendency can be weakened by increasing the excess air-fuel ratio. Cyclical variations of the HCCI engine are quantified by the coefficient of variation for the peak pressure (COV_P_m_a_x) and it exhibits an almost opposite trend to the knock tendency. The COV_P_m_a_x may considerably increase along with either increasing the blending ratio of n-butanol or increasing the excess air-fuel ratio. Moreover, it is reveled that the COV_P_m_a_x is sensitive to the relative position of peak HRR. The cyclical

  3. (Liquid + liquid) equilibria of aqueous solutions of butyric acid with n-heptane and toluene at T = (298.2, 308.2, and 318.2) K

    Ghanadzadeh Gilani, H.; Ghanadzadeh Gilani, A.; Janbaz, M.

    2013-01-01

    Highlights: ► Liquid equilibrium data of (water + butyric acid + n-heptane) were obtained. ► LLE data were correlated with NRTL and UNIQUAC models. ► Distribution coefficients and separation factors were evaluated. - Abstract: Solubility and tie line data for the (water + butyric acid + n-heptane) and (water + butyric acid + toluene) ternary systems were determined at T = (298.2, 308.2, and 318.2) K and atmospheric pressure. Solubility data were obtained by the cloud-point titration method. The concentration of each phase was determined by acidimetric titration, the Karl-Fischer technique, and refractive index measurements. The experimental tie-line data were correlated using the UNIQUAC and NRTL thermodynamic models. The reliability of the experimental data was determined through the Othmer–Tobias and Hand plots. Distribution coefficients and separation factors were evaluated for each system over the immiscibility regions.

  4. Extraction equilibria of amino acids by Di (2-ethylhexyl) phosphoric acid in n-heptane solutions; Di (2-ethylhexyl) rinsan no n-heptane yoeki ni yoru aminosan no chushutsu heiko

    Takahashi, M. [Suzuka National College of Technology, Mie (Japan); Tani, F. [Toyohashi University of Technology, Aichi (Japan); Kawai, Y. [Wako Jyunyaku Co. Ltd., Osaka (Japan); Takeuchi, H. [Nagoya University, Nagoya (Japan). Faculty of Engineering

    1997-03-10

    The extraction equilibria (i.e., distribution ratio) of amino acids by Di (2-ethyl hexyl) phosphoric acid in n-heptane solutions was investigated at a temperature of 298.2 K in the low pH range (of 2 to 5). The equal amount of an amino acid solution and an extracted solution with the predetermined concentration were shaken using a flask, and the concentration of amino acid in water phase was analyzed by a ninhydrin method. The concentration in organic phase was obtained by the concentration analysis in water phase and the material balance method after the amino acid is back-extracted by solution hydrochloride. The distribution ratio is in inverse proportion to the hydrogen ion concentration and in proportion to the 0.5th power of extracted agent concentration. The equilibrium constant is 0.650, 0.420, 0.320, 0.275, 0.064, and 0.040 mol{sup 0.5}/m{sup 1.5} in L-phenylalanine, L-tryptophane, L-leucine, L-methionine, glycine, and L-alanine, respectively. The equilibrium constant of the largest L-phenylalanine is 16 times as high as the smallest alanine. The extracted equilibrium constant increased as the hydrophobic property of amino acid increases. 18 refs., 10 figs., 1 tab.

  5. Compressed liquid densities for the (n-heptane + n-decane) and (n-octane + n-decane) systems from T = (313 to 363) K

    Quevedo-Nolasco, Rodolfo; Galicia-Luna, Luis A.; Elizalde-Solis, Octavio

    2012-01-01

    Highlights: → We built an equipment which consists of a variable volume cell and a VTD Anton Paar DMA-HPM. → Compressed liquid densities are reported for n-heptane and n-decane. → Binary (n-heptane or n-octane + n-decane) systems were studied in the whole range of composition. → Derived properties were calculated from experimental data. - Abstract: Densities (p, ρ, T, x 1 ) of two binary n-alkane systems are reported from T = (313 to 363) K in the compressed liquid phase up to 25 MPa over the whole range of composition. The binary mixtures {x 1 n-heptane + (1 - x 1 )n-decane} and {x 1 n-octane + (1 - x 1 )n-decane} were prepared at compositions of (x 1 = 0.0531, 0.2594, 0.5219, 0.777, 0.952), and (x 1 = 0.0616, 0.2801, 0.5314, 0.7736, 0.9623), respectively. A measuring system based on a vibrating tube densimeter, DMA HPM from Anton Paar with data acquisition system was developed in order to obtain experimental densities. Water and nitrogen were used as reference fluids to calibrate the densimeter. Experimental methodology was checked by comparing the n-heptane and n-decane densities against multi-parameter equations proposed in the literature. Differences between both sets of data show a maximum deviation of 0.07%. Excess molar volumes, isothermal compressibility and isobaric thermal expansivity were computed from experimental densities.

  6. Compressed liquid densities for the (n-heptane + n-decane) and (n-octane + n-decane) systems from T = (313 to 363) K

    Quevedo-Nolasco, Rodolfo [Laboratorio de Termodinamica, SEPI-ESIQIE, Instituto Politecnico Nacional, UPALM, Ed. Z, Secc. 6, 1ER piso, Lindavista, C.P. 07738 Mexico D.F. (Mexico); Galicia-Luna, Luis A., E-mail: lgalicial@ipn.mx [Laboratorio de Termodinamica, SEPI-ESIQIE, Instituto Politecnico Nacional, UPALM, Ed. Z, Secc. 6, 1ER piso, Lindavista, C.P. 07738 Mexico D.F. (Mexico); Elizalde-Solis, Octavio [Departamento de Ingenieria Quimica Petrolera, ESIQIE, Instituto Politecnico Nacional, UPALM, Edif. 8, 2o piso, Lindavista, C.P. 07738 Mexico D.F. (Mexico)

    2012-01-15

    Highlights: > We built an equipment which consists of a variable volume cell and a VTD Anton Paar DMA-HPM. > Compressed liquid densities are reported for n-heptane and n-decane. > Binary (n-heptane or n-octane + n-decane) systems were studied in the whole range of composition. > Derived properties were calculated from experimental data. - Abstract: Densities (p, {rho}, T, x{sub 1}) of two binary n-alkane systems are reported from T = (313 to 363) K in the compressed liquid phase up to 25 MPa over the whole range of composition. The binary mixtures {l_brace}x{sub 1}n-heptane + (1 - x{sub 1})n-decane{r_brace} and {l_brace}x{sub 1}n-octane + (1 - x{sub 1})n-decane{r_brace} were prepared at compositions of (x{sub 1} = 0.0531, 0.2594, 0.5219, 0.777, 0.952), and (x{sub 1} = 0.0616, 0.2801, 0.5314, 0.7736, 0.9623), respectively. A measuring system based on a vibrating tube densimeter, DMA HPM from Anton Paar with data acquisition system was developed in order to obtain experimental densities. Water and nitrogen were used as reference fluids to calibrate the densimeter. Experimental methodology was checked by comparing the n-heptane and n-decane densities against multi-parameter equations proposed in the literature. Differences between both sets of data show a maximum deviation of 0.07%. Excess molar volumes, isothermal compressibility and isobaric thermal expansivity were computed from experimental densities.

  7. (Liquid + liquid) equilibria measurements for ternary systems (sulfolane + a carboxylic acid + n-heptane) at T = 303.15 K and at 0.1 MPa

    Cele, N.P.; Bahadur, I.; Redhi, G.G.; Ebenso, E.E.

    2016-01-01

    Highlights: • The (liquid + liquid) equilibrium for (sulfolane + a carboxylic acid + heptane) was measured. • Selectivity values for solvent separation efficiency were calculated. • Separation of carboxylic acids from heptane is feasible by extraction. • Three parameter equations have been fitted to the binodal curve data. • The NRTL and UNIQUAC models were used to correlate the experimental data. - Abstract: In the present work, new (liquid + liquid) equilibrium (LLE) values are reported for ternary systems {sulfolane(1) + acetic acid, or propanoic acid, or butanoic acid, or 2-methylpropanoic acid, or pentanoic acid, or 3-methylbutanoic acid (2) + n-heptane (3)} at T = 303.15 K and at p = 0.1 MPa. The mutual solubility of carboxylic acid in sulfolane is dependent on the length and structure of the alkyl chain of the carboxylic acid; it progressively increases with an increase in the alkyl chain of the carboxylic acid. The single phase homogenous region increases as the alkyl chain of the carboxylic acid increases. The n-heptane is most soluble in the carboxylic acid mixtures with long alkyl chain, that is, (3-methylbutanoic acid + sulfolane) and (pentanoic acid + sulfolane) systems and least soluble in the carboxylic acid with short alkyl chain (acetic acid + sulfolane) system. Carboxylic acid together with many other oxygenates and hydrocarbons are produced by SASOL Company in South Africa using the Fischer–Tropsch process. The details about this process are given in introduction section. The NRTL and UNIQUAC models were used to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It was found that the NRTL model fits the experimental values significantly better than the UNIQUAC model.

  8. Carbon-based nanomaterial synthesis using nanosecond electrical discharges in immiscible layered liquids: n-heptane and water

    Hamdan, Ahmad; Cha, Min Suk

    2018-06-01

    Plasmas in- or in-contact with liquids have been extensively investigated due to their high potential for a wide range of applications including, but not limited to, water treatment, material synthesis and functionalization, bio-medical applications, and liquid fuel reformation. Recently, we successfully developed a discharge using two immiscible liquids, having very different electrical permittivities, which could significantly intensify the electric field intensity. Here, we establish nanosecond discharges at the interface n-heptane-water (with respective relative dielectric permittivities of 2 and 80) to enable the synthesis of carbon-based nanomaterials. A characterization of the as-synthesized material and the annealed (500 °C) material, using various techniques (Fourier-transform, infra-red, scanning and transmission electron microscopes, etc), shows that the as-synthesized material is a mixture of two carbon-based phases: a crystalline phase (graphite like) embedded into a phase of hydrogenated amorphous carbon. The existence of two-phases may be explained by the non-homogeneity of the discharge that induces various chemical reactions in the plasma channel.

  9. An Experimental Study on Burning Characteristics of n-Heptane/Ethanol Mixture Pool Fires in a Reduced Scaled Tunnel

    Yozgatligil, Ahmet; Shafee, Sina

    2016-11-01

    Fire accidents in recent decades have drawn attention to safety issues associated with the design, construction and maintenance of tunnels. A reduced scale tunnel model constructed based on Froude scaling technique is used in the current work. Mixtures of n-heptane and ethanol are burned with ethanol volumetric fraction up to 30 percent and the longitudinal ventilation velocity varying from 0.5 to 2.5 m/s. The burning rates of the pool fires are measured using a precision load cell. The heat release rates of the fires are calculated according to oxygen calorimetry method and the temperature distributions inside the tunnel are also measured. Results of the experiments show that the ventilation velocity variation has a significant effect on the pool fire burning rate, smoke temperature and the critical ventilation velocity. With increased oxygen depletion in case of increased ethanol content of blended pool fires, the quasi-steady heat release rate values tend to increase as well as the ceiling temperatures while the combustion duration decreases.

  10. Carbon-based nanomaterial synthesis using nanosecond electrical discharges in immiscible layered liquids: n-heptane and water

    Hamdan, Ahmad

    2018-05-14

    Plasmas in- or in-contact with liquids have been extensively investigated due to their high potential for a wide range of applications including but not limited to, water treatment, material synthesis and functionalization, bio-medical applications, and liquid fuel reformation. Recently, we successfully developed a discharge using two immiscible liquids, having very different electrical permittivities, which could significantly intensify the electric field intensity. Here, we establish nanosecond discharges at the interface n-heptane-water (with respective relative dielectric permittivities of 2 and 80) to enable the synthesis of carbon-based nanomaterials. A characterization of the as-synthesized material and the annealed (500 °C) material, using various techniques (Fourier-Transform, Infra-Red, Scanning and Transmission electron microscopes, etc.), shows that the as-synthesized material is a mixture of two carbon-based phases: a crystalline phase (graphite like) embedded into a phase of hydrogenated amorphous carbon. The existence of two-phases may be explained by the non-homogeneity of the discharge that induces various chemical reactions in the plasma channel.

  11. Permittivity and density of the systems (monoglyme, diglyme, triglyme, or tetraglyme + n-heptane) at several temperatures

    Riadigos, C.F.; Iglesias, R.; Rivas, M.A.; Iglesias, T.P.

    2011-01-01

    Relative permittivity and density on mixing at atmospheric pressure and temperatures from (288.15 to 308.15) K and atmospheric pressure have been measured over the entire composition range of mixing for {CH 3 O(CH 2 CH 2 O) m CH 3 with m = 1, 2, 3, 4 (also called monoglyme, diglyme, triglyme, or tetraglyme) + n-heptane}. The permittivity values were fitted as a function of the volume fraction and temperature to a logarithmic equation. The excess permittivity is calculated considering a definition that has been recently established in terms of the volume fraction. Excess molar volumes on mixing for the above systems have also been calculated. The density and excess molar volumes were fitted as a function of both mole fraction and temperature to a polynomial equation. The temperature dependence of derived magnitudes, (∂V m E /∂T) P,x and (∂H m E /∂P) T,x , was computed, given their importance in the study of specific molecular interactions. The experimental values of permittivity have been compared to those estimated by usual models of literature and the results indicate that the predictions are better when the volume change on mixing is incorporated in calculations. From the values of permittivity and density on mixing the dipole moment for tetraglyme was calculated. The work concludes with an interpretation of the sign of excess permittivity and its behaviour with temperature and that of excess molar volume.

  12. Influence on the interaction by functional groups in some series of bicyclo (2,2,1) heptane derivatives

    Gagnaire, Genevieve

    1971-01-01

    In connection with investigations involving the interactions of substituted groups in the bicyclo (2,2,1) heptane molecules, the chemical reactivity and some physical properties of polyfunctional compounds have been studied. A new method for preparation of β-fenchylic derivatives is presented, the first described terpenic nitroxide radical have been prepared from oxazolidinic compounds. The stereochemistry of the base induced elimination reaction of 6-exo tosyl and 6-endo tosyl oxy epi-camphor is dependent of the geometry of these compounds. On the other hand, the results indicate that the most important part of the structure is the position of the carbonyl group. Tricyclenic and camphenic derivatives are obtained with different rates. An explanation for these results involve several possible basic abstractions of acid protons, and the competition between these different reactions. The oxazolidinic compounds are obtained by reacting 2-amino 2-methyl 1-propanol with norcamphor and norbornane-2,5 dione. The geometrical configuration of the different stereoisomers is deduced from the measured dipolar interaction parameter D. The cotton effects of the γ-diketones do not show any interaction between the two carbonyl groups, in the fenchylic and bornylic series. The two carbonyl bond angles of the substituted α-diketones do not seem to be sensitive to any substitution of an alkoxy group. So, a new quadrant rule is proposed; compatible results are obtained, except for a methyl group in the α position. At least, PMR studies of terpenic polyfunctional compounds demonstrate the influence of the substitution on the geometry of the carbon skeleton. A new coupling constant 4 J HH is examined. (author) [fr

  13. Large eddy simulation of n-heptane spray combustion in partially premixed combustion regime with linear eddy model

    Xiao, Gang; Jia, Ming; Wang, Tianyou

    2016-01-01

    Spray combustion of n-heptane in a constant-volume vessel under engine-relevant conditions was investigated using linear eddy model in the framework of large eddy simulation. In this numerical approach, turbulent mixing was traced by an innovative stochastic approach instead of the conventional gradient diffusion model. Chemical reaction rates were calculated with the consideration of the sub-grid scale spatial fluctuations of reactive scalars. Turbulence-chemistry interactions were represented by the separated treatments of the underlying processes including turbulent stirring, chemical reaction, and molecular diffusion. The model was validated against the experimental data of ignition delay times, chemiluminescence images, and soot images from Sandia National Laboratories. Numerical results showed that the ignition process changed from the temperature-controlled regime to the mixing-controlled regime as the initial ambient temperature increased from 800 K to 1000 K. The premixed flame and the diffusion flame coexisted, while the gross heat release rate was found to be dominated by the premixed flame. The temperature fluctuation was mainly observed around the spray jet due to the cooling effect of the fuel vaporization. The fluctuations were more significantly smoothed out by the high-temperature flame than the low-temperature flame. The mean temperature would be overpredicted if the sub-grid temperature fluctuation was neglected. - Highlights: • Turbulent mixing is traced by stochastic method instead of gradient diffusion model. • Sub-grid scale fluctuations of reactive scalars are captured. • Ignition process varies from temperature-controlled to mixing-controlled regime. • Temperature fluctuation can be smoothed out by high-temperature flame. • The heat release rate is dominated by the premixed flame.

  14. An experimental investigation into combustion and performance characteristics of an HCCI gasoline engine fueled with n-heptane, isopropanol and n-butanol fuel blends at different inlet air temperatures

    Uyumaz, Ahmet

    2015-01-01

    Highlights: • Combustion was retarded with the increase of the amount of isopropanol and n-butanol in the test fuels. • Combustion was advanced with the increase of air inlet temperature on HCCI combustion. • Isopropanol seems more suitable fuel due to controlling the HCCI combustion and preventing knocking. • Almost zero NO emissions were measured when alcohol used except for n-heptane and B20 test fuels. - Abstract: An experimental study was conducted in a single cylinder, four stroke port injection Ricardo Hydra test engine in order to determine the effects of pure n-heptane, the blends of n-heptane and n-butanol fuels B20, B30, B40 (including 20%, 30%, 40% n-butanol and 80%, 70%, 60% n-heptane by vol. respectively) and the blends of n-heptane and isopropanol fuels P20, P30, P40 (including 20%, 30%, 40% isopropanol and 80%, 70%, 60% n-heptane by vol. respectively) on HCCI combustion. Combustion and performance characteristics of n-heptane, n-butanol and isopropanol were investigated at constant engine speed of 1500 rpm and λ = 2 in a HCCI engine. The effects of inlet air temperature were also examined on HCCI combustion. The test results showed that the start of combustion was advanced with the increasing of inlet air temperature for all test fuels. Start of combustion delayed with increasing percentage of n-butanol and isopropanol in the test fuels. Knocking combustion was seen with B20 and n-heptane test fuels. Minimum combustion duration was observed in case of using B40. Almost zero NO emissions were measured with test fuels apart from n-heptane and B20. The test results also showed that CO and HC emissions decreased with the increase of inlet air temperature for all test fuels. Isopropanol showed stronger resistance for knocking compared to n-butanol in HCCI combustion due to its higher octane number. It was determined that n-butanol was more advantageous according to isopropanol as thermal efficiency. As a result it was found that the HCCI

  15. Isothermal vapour-liquid equilibrium data for the binary systems of (CHF3 or C2F6) and n-heptane

    Williams-Wynn, Mark D.; Naidoo, Paramespri; Ramjugernath, Deresh

    2016-01-01

    Highlights: • Isothermal static-analytic and static-synthetic phase equilibrium measurements. • Binary VLE data for (CHF3 or C 2 F 6 ) + n-heptane. • Thermodynamic models were fitted to the experimental data. • Critical locus estimation for the systems. - Abstract: Isothermal vapour-liquid equilibrium (VLE) values for two binary systems; trifluoromethane and n-heptane at temperatures between T = (272.9 and 313.2) K, and hexafluoroethane and n-heptane at temperatures between T = (293.0 and 313.2) K were measured with a static-analytic apparatus. Bubble pressures at temperatures between T = (293.0 and 313.2) K, at several compositions, were also measured with a variable-volume static-synthetic apparatus. Vapour-liquid-liquid equilibrium (VLLE) was found to occur for certain isotherms for both of the systems. The PR EOS, with the Mathias-Copeman (MC) alpha function, combined with either the classical mixing rule or the Wong-Sandler (WS) mixing rule was used to correlate the experimental results. Either the NRTL or the UNIQUAC activity coefficient model was used within the WS mixing rule. The indirect extended scaling laws of Ungerer et al. were used to extrapolate critical loci from the experimental coexistence data, and the calculation procedure of Heidemann and Khalil was employed to calculate the mixture critical locus curves at temperatures close to the refrigerant critical temperatures. At lower temperatures on the mixture critical curve, gas-liquid critical points occurred, whereas, at higher temperatures, the critical points occurred along a liquid-liquid locus curve. The two systems were categorised according to the van Konynenburg and Scott classification.

  16. Pyrrole and 2,5-heptanedione in the urine of rats and 2,5-heptanedione in the urine of man: analytical determination of excretion upon exposure to n-heptane; Pyrrole und 2,5-Heptandion im Urin der Ratte und 2,5-Heptandion im Urin des Menschen: Analytische Bestimmung der Ausscheidung nach Exposition gegn n-Heptan

    Stoermer, A.G.C.

    1997-09-01

    A method for quantifying levels of the neurotoxic metabolite 2,5-heptanedione in rats and man after experimental exposure to n-heptane was developed. It consisted in determining the quantity of 2,5-heptanedione excreted in urine and the relevant excretion kinetics. Moreover, the excretion of pyrrole in the urine of rats was measured. In the urine of non-exposed rats and man, a basic excretion of 2,5-heptanedione was measured, with the rates of excretion being 0.11 and 4.5 nmol per hour, respectively. This basic excretion of 2,5-heptanedione is assumed to have an endogenous cause. The quantitive investigation of the dose dependence of the excretion of 2,5-heptanedione and pyrrole in the urine of rats and of 2,5-heptanedione in the urine of man is a prerequisite for assessing the risk posed by n-heptane with a view to peripheral neuropathies. (orig./MG) [Deutsch] Ziel dieser Arbeit war die Entwicklung einer Methode zur Quantifizierung der Belastung von Ratte und Mensch mit dem neurotoxischen Metaboliten 2,5-Heptandion nach experimentellen Expositionen gegen n-Heptan. Dazu sollte jeweils die ausgeschiedene Menge und die zugehoerige Ausscheidungskinetik von 2,5-Heptandion im Urin bestimmt werden. Darueber hinaus sollte die Ausscheidung von Pyrrolen im Urin von Ratten gemessen werden. Im Urin von nicht exponierten Ratten und Menschen wurde eine Grundausscheidung von 2,5-Heptandion gefunden, wobei die Ausscheidungsraten jeweils 0,11 bzw. 4,5 nmol/h betrugen. Fuer die Grundausscheidung von 2,5-Heptandion wird ein endogener Ursprung angenommen. Die quantitativen Untersuchungen zur Dosisabhaengigkeit der Ausscheidung im Urin von 2,5-Heptandion und Pyrrolen bei der Ratte und von 2,5-Heptandion beim Menschen sind eine Grundvoraussetzung fuer eine Abschaetzung des Risikos von n-Heptan fuer periphere Neuropathien. (orig./MG)

  17. A reduced mechanism for predicting the ignition timing of a fuel blend of natural-gas and n-heptane in HCCI engine

    Bahlouli, Keyvan; Atikol, Ugur; Khoshbakhti Saray, R.; Mohammadi, Vahid

    2014-01-01

    Highlights: • A two-stage reduction process is used to produce two reduced mechanisms. • The mechanisms are combined to develop a reaction mechanism for a fuel blend. • The genetic algorithm is used for optimization of reaction constants. • The developed reduced mechanism can be used to predict the ignition timing in HCCI engine for a fuel blend. - Abstract: One of the main challenges associated with homogeneous charge compression ignition (HCCI) combustion engine application is the lack of direct control on ignition timing. One of the solutions to this problem is mixing two fuels with various properties at a variety of ratios on a cycle-by-cycle basis. In the current study, a reduced mechanism for a fuel blend of natural-gas and n-heptane is proposed. The approach is validated for the prediction of ignition timing in the HCCI combustion engine. A single-zone combustion model is used to simulate the HCCI engine. A two-stage reduction process is used to produce two reduced mechanisms of existing semi-detailed GRI-Mech. 3.0 mechanism that contains 53 species and 325 reactions and Golovichev’s mechanism consisting of 57 species and 290 reactions for natural gas and n-heptane fuels, respectively. Firstly, the unimportant species and related reactions are identified by employing the directed relation graph with error propagation (DRGEP) reduction method and then, to extend reduction, the principal component analysis (PCA) method is utilized. To evaluate the validity of the reduced mechanism, representative engine combustion parameters such as peak pressure, maximum heat release, and CA50 are used. The reduced mechanism of GRI-Mech. 3.0 mechanism, containing 19 species and 39 reactions, and the reduced mechanism of Golovichev’s mechanism, consisting of 40 species and 95 reactions, provide good prediction for the mentioned parameters in comparison with those of detailed mechanisms. The combination of the generated reduced mechanisms is used to develop a

  18. Bicyclo[3.2.0]heptane as a Core Structure for Conformational Locking of 1,3-Bis-Pharmacophores, Exemplified by GABA

    Vorberg, Raffael; Trapp, Nils; Carreira, Erick M

    2017-01-01

    The synthesis and X-ray crystal structures of syn and anti 4-N-Boc-aminobicyclo[3.2.0]heptane-1-carboxylic acids are described. The placement of the N-Boc-amino groups in the two stereoisomers in either pseudo-equatorial or pseudo-axial positions renders the molecules conformationally locked......, with N-Boc-protected γ-aminobutyric acid (GABA) embedded within the bicyclic core. Despite the different conformations of the urethane and distinct crystal packing, the bicyclic core units of the two stereoisomers adopt virtually identical structures. They correspond to in silico models of the parent...

  19. Excess enthalpies of binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol, and heptane at T = 298.15 K and 313.15 K

    Aguilar, Fernando; Alaoui, Fatima E.M.; Segovia, Jose J.; Villamanan, Miguel A.; Montero, Eduardo A.

    2010-01-01

    Experimental excess molar enthalpies of the ternary systems {dibutyl ether (DBE) + 1-butanol + heptane} and the corresponding binary systems at T = 298.15 K and T = 313.15 K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and the ternary systems show endothermic character. The experimental data for the binary and ternary systems have been fitted using the Redlich-Kister equation, the NRTL and UNIQUAC models. The values of the standard deviation indicate good agreement between the experimental results and those calculated from the equations.

  20. Autoignition characterization of primary reference fuels and n-heptane/n-butanol mixtures in a constant volume combustion device and homogeneous charge compression ignition engine

    Baumgardner, Marc E.

    2013-12-19

    In this study, the autoignition behavior of primary reference fuels (PRF) and blends of n-heptane/n-butanol were examined in a Waukesha Fuel Ignition Tester (FIT) and a Homogeneous Charge Compression Engine (HCCI). Fourteen different blends of iso-octane, n-heptane, and n-butanol were tested in the FIT - 28 test runs with 25 ignition measurements for each test run, totaling 350 individual tests in all. These experimental results supported previous findings that fuel blends with high alcohol content can exhibit very different ignition delay periods than similarly blended reference fuels. The experiments further showed that n-butanol blends behaved unlike PRF blends when comparing the autoignition behavior as a function of the percentage of low reactivity component. The HCCI and FIT experimental results favorably compared against single and multizone models with detailed chemical kinetic mechanisms - both an existing mechanism as well as one developed during this study were used. The experimental and modeling results suggest that that the FIT instrument is a valuable tool for analysis of high pressure, low temperature chemistry, and autoignition for future fuels in advanced combustion engines. Additionally, in both the FIT and engine experiments the fraction of low temperature heat release (fLTHR) was found to correlate very well with the crank angle of maximum heat release and shows promise as a useful metric for fuel reactivity in advanced combustion applications. © 2013 American Chemical Society.

  1. Vapor phase nucleation of the short-chain n-alkanes (n-pentane, n-hexane and n-heptane): Experiments and Monte Carlo simulations

    Ogunronbi, Kehinde E.; Sepehri, Aliasghar; Chen, Bin; Wyslouzil, Barbara E.

    2018-04-01

    We measured the nucleation rates of n-pentane through n-heptane in a supersonic nozzle at temperatures ranging from ca. 109 K to 168 K. For n-pentane and n-hexane, these are the first nucleation rate measurements that have been made, and the trends in the current data agree well with those in the earlier work of Ghosh et al. [J. Chem. Phys. 132, 024307 (2010)] for longer chain alkanes. Complementary Monte Carlo simulations, using the transferable potentials for phase equilibria-united atom potentials, suggest that despite the high degree of supercooling, the critical clusters remain liquid like under experimental conditions for n-pentane through n-heptane, but adopt more ordered structures for n-octane and n-nonane. For all three alkanes, the experimental and simulated nucleation rates are offset by ˜3 orders of magnitude when plotted as a function of ln S/(Tc/T - 1)1.5. Explicitly accounting for the surface tension difference between the real and model substances, or alternatively using the Hale [Phys. Rev. A 33, 4156 (1986); Metall. Mater. Trans. A 23, 1863 (1992)] scaling parameter, Ω, consistent with the model potential, increases the offset to ˜6 orders of magnitude.

  2. Bottom-up coarse-grained models with predictive accuracy and transferability for both structural and thermodynamic properties of heptane-toluene mixtures.

    Dunn, Nicholas J H; Noid, W G

    2016-05-28

    This work investigates the promise of a "bottom-up" extended ensemble framework for developing coarse-grained (CG) models that provide predictive accuracy and transferability for describing both structural and thermodynamic properties. We employ a force-matching variational principle to determine system-independent, i.e., transferable, interaction potentials that optimally model the interactions in five distinct heptane-toluene mixtures. Similarly, we employ a self-consistent pressure-matching approach to determine a system-specific pressure correction for each mixture. The resulting CG potentials accurately reproduce the site-site rdfs, the volume fluctuations, and the pressure equations of state that are determined by all-atom (AA) models for the five mixtures. Furthermore, we demonstrate that these CG potentials provide similar accuracy for additional heptane-toluene mixtures that were not included their parameterization. Surprisingly, the extended ensemble approach improves not only the transferability but also the accuracy of the calculated potentials. Additionally, we observe that the required pressure corrections strongly correlate with the intermolecular cohesion of the system-specific CG potentials. Moreover, this cohesion correlates with the relative "structure" within the corresponding mapped AA ensemble. Finally, the appendix demonstrates that the self-consistent pressure-matching approach corresponds to minimizing an appropriate relative entropy.

  3. Bottom-up coarse-grained models with predictive accuracy and transferability for both structural and thermodynamic properties of heptane-toluene mixtures

    Dunn, Nicholas J. H.; Noid, W. G., E-mail: wnoid@chem.psu.edu [Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802 (United States)

    2016-05-28

    This work investigates the promise of a “bottom-up” extended ensemble framework for developing coarse-grained (CG) models that provide predictive accuracy and transferability for describing both structural and thermodynamic properties. We employ a force-matching variational principle to determine system-independent, i.e., transferable, interaction potentials that optimally model the interactions in five distinct heptane-toluene mixtures. Similarly, we employ a self-consistent pressure-matching approach to determine a system-specific pressure correction for each mixture. The resulting CG potentials accurately reproduce the site-site rdfs, the volume fluctuations, and the pressure equations of state that are determined by all-atom (AA) models for the five mixtures. Furthermore, we demonstrate that these CG potentials provide similar accuracy for additional heptane-toluene mixtures that were not included their parameterization. Surprisingly, the extended ensemble approach improves not only the transferability but also the accuracy of the calculated potentials. Additionally, we observe that the required pressure corrections strongly correlate with the intermolecular cohesion of the system-specific CG potentials. Moreover, this cohesion correlates with the relative “structure” within the corresponding mapped AA ensemble. Finally, the appendix demonstrates that the self-consistent pressure-matching approach corresponds to minimizing an appropriate relative entropy.

  4. Direct numerical simulations of ignition of a lean n-heptane/air mixture with temperature and composition inhomogeneities relevant to HCCI and SCCI combustion

    Luong, Minh Bau

    2015-12-01

    The effects of temperature and composition stratifications on the ignition of a lean n-heptane/air mixture at three initial mean temperatures under elevated pressure are investigated using direct numerical simulations (DNSs) with a 58-species reduced mechanism. Two-dimensional DNSs are performed by varying several key parameters: initial mean temperature, T0, and the variance of temperature and equivalence ratio (T\\' and φ\\') with different T-φcorrelations. It is found that for cases with φ\\' only, the overall combustion occurs more quickly and the mean heat release rate (HRR) increases more slowly with increasing φ\\' regardless of T0. For cases with T\\' only, however, the overall combustion is retarded/advanced in time with increasing T\\' for low/high T0 relative to the negative-temperature coefficient (NTC) regime resulting from a longer/shorter overall ignition delay of the mixture. For cases with uncorrelated T-φfields, the mean HRR is more distributed over time compared to the corresponding cases with T\\' or φ\\' only. For negatively-correlated cases, however, the temporal evolution of the overall combustion exhibits quite non-monotonic behavior with increasing T\\' and φ\\' depending on T0. All of these characteristics are found to be primarily related to the 0-D ignition delays of initial mixtures, the relative timescales between 0-D ignition delay and turbulence, and the dominance of the deflagration mode during the ignition. These results suggest that an appropriate combination of T\\' and φ\\' together with a well-prepared T-φdistribution can alleviate an excessive pressure-rise rate (PRR) and control ignition-timing in homogeneous charge compression-ignition (HCCI) combustion. In addition, critical species and reactions for the ignition of n-heptane/air mixture through the whole ignition process are estimated by comparing the temporal evolution of the mean mass fractions of important species with the overall reaction pathways of n-heptane

  5. Changes of refractive indices in ternary mixtures containing chlorobenzene + n-hexane + (n-heptane or n-octane at 298.15 K

    M. IGLESIAS

    2004-06-01

    Full Text Available The refractive indices of ternary mixtures of chlorobenzene + n-hexane + (n-heptane or n-octane have been measured at 298.15 K and at atmospheric pressure over the whole composition diagram. Parameters of polynomial equations which represent the composition dependence of physical and derived properties are gathered. The experimental refractive indices and the ternary derived properties are compared with the data obtained using several predictive semi-empirical models. The use of the Soave–Redlich–Kwong (SRK and the Peng–Robinson (PR cubic equations of state with the Van der Waals one-fluid mixing rule, which incorporate different combining rules to predict refractive indices on mixing, are tested against the measured results, good agrement being obtained.

  6. Rapid evaporation at the superheat limit of methanol, ethanol, butanol and n-heptane on platinum films supported by low-stress SiN membranes.

    Ching, Eric J; Avedisian, C Thomas; Cavicchi, Richard C; Chung, Do Hyun; Rah, Jeff; Carrier, Michael J

    2016-10-01

    The bubble nucleation temperatures of several organic liquids (methanol, ethanol, butanol, n-heptane) on stress-minimized platinum (Pt) films supported by SiN membranes is examined by pulse-heating the membranes for times ranging from 1 µs to 10 µs. The results show that the nucleation temperatures increase as the heating rates of the Pt films increase. Measured nucleation temperatures approach predicted superheat limits for the smallest pulse times which correspond to heating rates over 10 8 K/s, while nucleation temperatures are significantly lower for the longest pulse times. The microheater membranes were found to be robust for millions of pulse cycles, which suggests their potential in applications for moving fluids on the microscale and for more fundamental studies of phase transitions of metastable liquids.

  7. Phase equilibria of toluene/heptane with deep eutectic solvents based on ethyltriphenylphosphonium iodide for the potential use in the separation of aromatics from naphtha

    Kareem, Mukhtar A.; Mjalli, Farouq S.; Hashim, Mohd Ali; Hadj-Kali, Mohamed K.O.; Ghareh Bagh, Fatemeh Saadat; Alnashef, Inas M.

    2013-01-01

    Highlights: • Ionic liquid analogues are introduced as potential replacements for ionic liquids. • Deep eutectic solvents presented in this work were successful for extracting aromatics. • Hand correlation was applied to ascertain the experimental measurements. • The NRTL thermodynamic model was capable for correlating the LLE experimental data. -- Abstract: In this work, the liquid–liquid extraction of toluene from hydrocarbons mixtures (toluene/heptane) was investigated using deep eutectic solvents as solvents. Ethyltriphenylphosphonium iodide as a salt with either ethylene glycol or sulfolane as hydrogen-bond donors (HBDs) were utilized for synthesizing six DESs. (Liquid + liquid) equilibria data were determined experimentally for the ternary system (toluene + heptane + DES) at (30, 40, 50, and 60) °C and atmospheric pressure. Hand correlation was applied to establish the reliability of the experimental data. In many cases the correlation factor is found close to unity which indicates high reliability of the data. The selectivities and distribution coefficients were used to determine the suitability of these DESs as solvents for this extraction process. Higher selectivities than those published for sulfolane as a commercial solvent were observed. The DES made from ethyltriphenylphosphonium iodide and sulfolane at salt:HBD of 1:4 showed the best separation capability at 30 °C. Thus, it was further characterized by measuring its viscosity and refractive index at a range of temperatures to help understand its physical behaviour needed for process design. The non-random two-liquid (NRTL) model was applied successfully to correlate the experimental tie-lines and to calculate the phase compositions of the ternary systems. It has been found that the third non-randomness parameter varies linearly with the HBD number of moles

  8. Effect of Temperature, Pressure and Equivalence Ratio on Ignition Delay in Ignition Quality Tester (IQT): Diesel,n-Heptane, andiso-Octane Fuels under Low Temperature Conditions

    Yang, Seung Yeon

    2015-11-02

    Effects of temperature, pressure and global equivalence ratio on total ignition delay time in a constant volume spray combustion chamber were investigated for diesel fuel along with the primary reference fuels (PRFs) of n-heptane and iso-octane in relatively low temperature conditions to simulate unsteady spray ignition behavior. A KAUST Research ignition quality tester (KR-IQT) was utilized, which has a feature of varying temperature, pressure and equivalence ratio using a variable displacement fuel pump. A gradient method was adopted in determining the start of ignition in order to compensate pressure increase induced by low temperature heat release. Comparison of this method with other existing methods was discussed. Ignition delay times were measured at various equivalence ratios (0.5-1.7) with the temperatures of initial charge air in the range from 698 to 860 K and the pressures in the range of 1.5 to 2.1 MPa, pertinent to low temperature combustion (LTC) conditions. An attempt to scale the effect of pressure on total ignition delay was undertaken and the equivalence ratio exponent and activation energy in the Arrhenius expression of total ignition delay were determined. Ignition delay results indicated that there were strong correlations of pressure, temperature, and equivalence ratio under most conditions studied except at relatively low pressures. Diesel (DCN 52.5) and n-heptane (DCN 54) fuels exhibited reasonably similar ignition delay characteristics, while iso-octane showed a distinct behavior under low temperature regime having a two-stage ignition, which substantiate the adoption of the gradient method in determining ignition delay.

  9. The liquid–liquid coexistence curves of {x dimethyl adipate + (1 − x) n-hexane} and {x dimethyl adipate + (1 − x) n-heptane} in the critical region

    Chen Zhiyun; Cai Li; Huang Meijun; Yin Tianxiang; An Xueqin; Shen Weiguo

    2012-01-01

    Highlights: ► Coexistence curves of (dimethyl adipate + n-hexane) (+n-heptane) were measured. ► The critical exponent β are consistent with the 3D-Ising value. ► The asymmetry of the coexistence curves were discussed by complete scaling theory. - Abstract: The liquid–liquid coexistence curves for (dimethyl adipate + n-hexane), (dimethyl adipate + n-heptane) have been measured, from which the critical amplitudes and the critical exponents are deduced. The critical exponent β corresponding to the coexistence curves are consistent with the 3D-Ising value. The experimental results have also been analyzed to determine the critical amplitudes of Wegner-correction terms when β and Δ are fixed at their theoretical values, and to examine the asymmetry of the diameters for the coexistence curves.

  10. Stereoisomerism and muscarinic receptor agonists: Synthesis and effects of the stereoisomers of 3-[5-(3-amino-1,2,4-oxadizol)yl]-1-azabicyclo[2.2.1]heptane

    Pombo-Villar, E.; Wiederhold, K.-H.; Mengod, G.; Palacios, J.M.; Supavilai, P.; Boddeke, H.W.G.M.

    1992-01-01

    The preparation and the biological activities of the four stereoisomers of 3-[5-(3-amino-1,2,5-oxadiazol)yl]-1-azabicyclo [2.2.1]heptane are described. The most potent stereoisomer, 3a, has the 3R,4R configuration, and in vitro activities in (pD2(% efficacy): ileum 8.8 (87%), hippocampus 9.8 (116%)

  11. STEREOISOMERISM AND MUSCARINIC RECEPTOR AGONISTS - SYNTHESIS AND EFFECTS OF THE STEREOISOMERS OF 3-[5-(3-AMINO-1,2,4-OXADIAZOL)YL]-1-AZABICYCLO[2.2.1]HEPTANE

    POMBOVILLAR, E; WIEDERHOLD, KH; MENGOD, G; PALACIOS, JM; SUPAVILAI, P; BODDEKE, HWGM

    1992-01-01

    The preparation and the biological activities of the four stereoisomers of 3-[5-(3-amino-1,2,4-oxadiazol)yl]-1-azabicyclo [2.2.1]heptane are described. The most potent stereoisomer, 3a, has the 3R,4R configuration, and in vitro activities in (pD2(% efficacy): ileum 8.8 (87%), hippocampus 9.8 (116%)

  12. Effect of the particle size and surface area of tungstated zirconia on the WOx nuclearity and n-heptane isomerization over Pt/WO3–ZrO2

    Kaucký, Dalibor; Wichterlová, Blanka; Dědeček, Jiří; Sobalík, Zdeněk; Jakubec, Ivo

    2011-01-01

    Roč. 397, 1-2 (2011), s. 82-93 ISSN 0926-860X R&D Projects: GA AV ČR KAN100400702 Institutional research plan: CEZ:AV0Z40320502; CEZ:AV0Z40400503 Keywords : n-heptane isomeration * Pt/WO3-ZrO2 * nano ZrO2 Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.903, year: 2011

  13. Separation of toluene and heptane by liquid-liquid extraction using z-methyl-N-butylpyridinium tetrafluoroborate isomers (z = 2, 3, or 4) at T = 313.2 K

    Garcia, Julian; Garcia, Silvia; Torrecilla, Jose S.; Oliet, Mercedes; Rodriguez, Francisco

    2010-01-01

    The (liquid + liquid) equilibrium (LLE) data for three ternary systems containing heptane, toluene, and a z-methyl-N-butylpyridinium tetrafluoroborate ionic liquid ([zbmpy][BF 4 ] IL, where z = 2, 3, or 4) were determined at T = 313.2 K and atmospheric pressure. The effect of IL cation isomers on the LLE data was evaluated for the first time. The selectivity and extractive capacity from these LLE data were calculated and compared to those previously reported in the literature for the systems (heptane + toluene + [4bmpy][BF 4 ]) and (heptane + toluene + sulfolane). The results show that the LLE data for the systems comprising the ILs with the metha- and para-substituted cations do not differ significantly from isomer to isomer. On the other hand, significant differences were observed among the systems with the ortho-substituted cation and the other two cation isomers. The degree of consistency of the experimental LLE data was ascertained by applying the Othmer-Tobias correlation. In addition, the LLE data were satisfactorily correlated by means of the thermodynamic NRTL model.

  14. A methodology to relate octane numbers of binary and ternary n-heptane, iso-octane and toluene mixtures with simulated ignition delay times

    Badra, Jihad A.

    2015-08-11

    Predicting octane numbers (ON) of gasoline surrogate mixtures is of significant importance to the optimization and development of internal combustion (IC) engines. Most ON predictive tools utilize blending rules wherein measured octane numbers are fitted using linear or non-linear mixture fractions on a volumetric or molar basis. In this work, the octane numbers of various binary and ternary n-heptane/iso-octane/toluene blends, referred to as toluene primary reference fuel (TPRF) mixtures, are correlated with a fundamental chemical kinetic parameter, specifically, homogeneous gas-phase fuel/air ignition delay time. Ignition delay times for stoichiometric fuel/air mixtures are calculated at various constant volume conditions (835 K and 20 atm, 825 K and 25 atm, 850 K and 50 atm (research octane number RON-like) and 980 K and 45 atm (motor octane number MON-like)), and for variable volume profiles calculated from cooperative fuel research (CFR) engine pressure and temperature simulations. Compression ratio (or ON) dependent variable volume profile ignition delay times are investigated as well. The constant volume RON-like ignition delay times correlation with RON was the best amongst the other studied conditions. The variable volume ignition delay times condition correlates better with MON than the ignition delay times at the other tested conditions. The best correlation is achieved when using compression ratio dependent variable volume profiles to calculate the ignition delay times. Most of the predicted research octane numbers (RON) have uncertainties that are lower than the repeatability and reproducibility limits of the measurements. Motor octane number (MON) correlation generally has larger uncertainties than that of RON.

  15. Influence of turbulence-chemistry interaction for n-heptane spray combustion under diesel engine conditions with emphasis on soot formation and oxidation

    Bolla, Michele; Farrace, Daniele; Wright, Yuri M.; Boulouchos, Konstantinos; Mastorakos, Epaminondas

    2014-03-01

    The influence of the turbulence-chemistry interaction (TCI) for n-heptane sprays under diesel engine conditions has been investigated by means of computational fluid dynamics (CFD) simulations. The conditional moment closure approach, which has been previously validated thoroughly for such flows, and the homogeneous reactor (i.e. no turbulent combustion model) approach have been compared, in view of the recent resurgence of the latter approaches for diesel engine CFD. Experimental data available from a constant-volume combustion chamber have been used for model validation purposes for a broad range of conditions including variations in ambient oxygen (8-21% by vol.), ambient temperature (900 and 1000 K) and ambient density (14.8 and 30 kg/m3). The results from both numerical approaches have been compared to the experimental values of ignition delay (ID), flame lift-off length (LOL), and soot volume fraction distributions. TCI was found to have a weak influence on ignition delay for the conditions simulated, attributed to the low values of the scalar dissipation relative to the critical value above which auto-ignition does not occur. In contrast, the flame LOL was considerably affected, in particular at low oxygen concentrations. Quasi-steady soot formation was similar; however, pronounced differences in soot oxidation behaviour are reported. The differences were further emphasised for a case with short injection duration: in such conditions, TCI was found to play a major role concerning the soot oxidation behaviour because of the importance of soot-oxidiser structure in mixture fraction space. Neglecting TCI leads to a strong over-estimation of soot oxidation after the end of injection. The results suggest that for some engines, and for some phenomena, the neglect of turbulent fluctuations may lead to predictions of acceptable engineering accuracy, but that a proper turbulent combustion model is needed for more reliable results.

  16. Stabilization and structure of N-heptane flame on CWJ-spray burner with kHZ SPIV and OH-PLIF

    Mansour, Morkous S.

    2015-08-31

    A curved wall-jet (CWJ) burner was employed to stabilize turbulent spray flames that utilized a Coanda effect by supplying air as annular-inward jet over a curved surface, surrounding an axisymmetric solid cone fuel spray. The stabilization characteristics and structure of n-heptane/air turbulent flames were investigated with varying fuel and air flow rates and the position of pressure atomizer (L). High-speed planar laser-induced fluorescence (PLIF) of OH radicals delineated reaction zone contours and simultaneously stereoscopic particle image velocimetry (SPIV) quantified the flow field features, involving turbulent mixing within spray, ambient air entrainment and flame-turbulence interaction. High turbulent rms velocities were generated within the recirculation zone, which improved the flame stabilization. OH fluorescence signals revealed a double flame structure near the stabilization edge of lifted flame that consisted of inner partially premixed flame and outer diffusion flame front. The inner reaction zone is highly wrinkled and folded due to significant turbulent mixing between the annular-air jet and the fuel vapor generated from droplets along the contact interface of this air jet with the fuel spray. Larger droplets, having higher momentum are able to penetrate the inner reaction zone and then vaporized in the low-speed hot region bounded by these reaction zones; this supports the outer diffusion flame. Frequent local extinctions in the inner reaction zone were observed at low air flow rate. As flow rate increases, the inner zone is more resistant to local extinction despite of its high wrinkling and corrugation degree. However, the outer reaction zone exhibits stable and mildly wrinkled features irrespective of air flow rate. The liftoff height increases with the air mass flow rate but decreases with L.

  17. Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

    Jaasim, Mohammed

    2018-04-04

    Numerical simulations were conducted to systematically assess the effects of different spray models on the ignition delay predictions and compared with experimental measurements obtained at the KAUST ignition quality tester (IQT) facility. The influence of physical properties and chemical kinetics over the ignition delay time is also investigated. The IQT experiments provided the pressure traces as the main observables, which are not sufficient to obtain a detailed understanding of physical (breakup, evaporation) and chemical (reactivity) processes associated with auto-ignition. A three-dimensional computational fluid dynamics (CFD) code, CONVERGE™, was used to capture the detailed fluid/spray dynamics and chemical characteristics within the IQT configuration. The Reynolds-averaged Navier-Stokes (RANS) turbulence with multi-zone chemistry sub-models was adopted with a reduced chemical kinetic mechanism for n-heptane and iso-octane. The emphasis was on the assessment of two common spray breakup models, namely the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) and linearized instability sheet atomization (LISA) models, in terms of their influence on auto-ignition predictions. Two spray models resulted in different local mixing, and their influence in the prediction of auto-ignition was investigated. The relative importance of physical ignition delay, characterized by spray evaporation and mixing processes, in the overall ignition behavior for the two different fuels were examined. The results provided an improved understanding of the essential contribution of physical and chemical processes that are critical in describing the IQT auto-ignition event at different pressure and temperature conditions, and allowed a systematic way to distinguish between the physical and chemical ignition delay times.

  18. Density, viscosity and excess molar volume of binary mixtures of tri-n-octylamine + diluents (n-heptane, n-octane, n-nonane, and n-decane) at various temperatures

    Fang, Sheng; Zuo, Xiao-Bo; Xu, Xue-Jiao; Ren, Da-Hai

    2014-01-01

    Highlights: • Densities and viscosities of tri-n-octylamine + n-heptane, +n-octane, +n-nonane, or +n-decane are determined. • The excess molar volume is calculated. • The Grunberg and Nissan equation and Fang and He equation are used to correlate the binary viscosities. -- Abstract: Densities (ρ) and viscosities (η) for binary mixtures of tri-n-octylamine (TOA) + n-heptane, TOA + n-octane, TOA + n-nonane, and TOA + n-decane are determined at T (283.15, 293.15, and 303.15) K and atmospheric pressure. The excess molar volume is calculated from the density data and is correlated by a Redlich–Kister type equation. The excess molar volume is negative for all the four systems. The results show that the volume accommodation effect is predominant in these systems. The Grunberg and Nissan equation and Fang and He equation for binary mixtures are used to correlate the experimental viscosity data. The Fang and He equation gives an average absolute deviation (AAD%) of 0.8% for TOA with alkane mixtures, better than that of 3.8% given by the Grunberg and Nissan equation

  19. Correlation and prediction of the phase behavior and thermal properties of binary and ternary systems of 2,2′-oxybis[propane] + benzene, toluene, cyclohexane or n-heptane

    Didaoui, Saéda, E-mail: sdidaoui@hotmail.com [Laboratoire de thermodynamique et de modélisation moléculaire, Faculté de chimie, Université des Sciences et de la Technologie Houari Boumediene B.P.32, El-Alia Bab-Ezzouar 16111 Alger (Algeria); Ait-Kaci, Ahmed [Laboratoire de thermodynamique et de modélisation moléculaire, Faculté de chimie, Université des Sciences et de la Technologie Houari Boumediene B.P.32, El-Alia Bab-Ezzouar 16111 Alger (Algeria)

    2013-09-10

    Highlights: ► To provide original data of excess enthalpies of systems containing additive gasoline. ► To predict excess functions using statistical model. ► To examine the thermal behavior of ethers with hydrocarbons using theoretical models. ► Increasing information of thermodynamic behavior will increase quality of the fuel and economy. - Abstract: The experimental excess molar enthalpies data of liquid binary and ternary mixtures of DIPE with benzene, toluene, cyclohexane and n-heptane have been measured at 303.15 K and constant pressure using a Calvet type microcalorimeter, C80 (Setaram, France). A Redlich–Kister type equation was used to correlate experimental values. The theoretical results obtained by the DISQUAC model are significantly closer to the experimental values.

  20. Correlation and prediction of the phase behavior and thermal properties of binary and ternary systems of 2,2′-oxybis[propane] + benzene, toluene, cyclohexane or n-heptane

    Didaoui, Saéda; Ait-Kaci, Ahmed

    2013-01-01

    Highlights: ► To provide original data of excess enthalpies of systems containing additive gasoline. ► To predict excess functions using statistical model. ► To examine the thermal behavior of ethers with hydrocarbons using theoretical models. ► Increasing information of thermodynamic behavior will increase quality of the fuel and economy. - Abstract: The experimental excess molar enthalpies data of liquid binary and ternary mixtures of DIPE with benzene, toluene, cyclohexane and n-heptane have been measured at 303.15 K and constant pressure using a Calvet type microcalorimeter, C80 (Setaram, France). A Redlich–Kister type equation was used to correlate experimental values. The theoretical results obtained by the DISQUAC model are significantly closer to the experimental values

  1. Effect of SiO2/Al2O3 Ratio on Micro-Mesopore Formation for Pt/Beta-MCM-41 via NaOH Treatment and the Catalytic Performance in N-heptane Hydro isomerization

    Gao, Li; Shi, Zhiyuan; Liu, Yingming; Zhao, Yuanshou; Liu, Qinghua; Xu, Chengguo; Bai, Peng; Yan, Zifeng

    2018-01-01

    Micro-mesoporous composite material Beta-MCM-41(BM) were hydrothermally synthesized by treating parent beta with molar SiO2/Al2O3 ratios of 12.5, 20 and 30 as precursors. The influence of SiO2/Al2O3 ratio of zeolite beta on effective micro-mesoporous composite formation was studied by investigating the crystallinity, morphology, chemical composition, acidity and textural property of Beta-MCM-41 through XRD, nitrogen adsorption, SEM, TEM, NH3-TPD, FTIR and Pyridine-FTIR. The catalytic performance was evaluated in terms of n-heptane hydro isomerization. The results demonstrated that Beta-MCM-41 supported Pt catalysts showed higher selectivity to isoheptanes than Pt/Beta. It was attributed to the superiorities of the pore structure and mesoporous accelerated the diffusion of larger molecules of isoheptanes.

  2. New carbocyclic N(6)-substituted adenine and pyrimidine nucleoside analogues with a bicyclo[2.2.1]heptane fragment as sugar moiety; synthesis, antiviral, anticancer activity and X-ray crystallography.

    Tănase, Constantin I; Drăghici, Constantin; Cojocaru, Ana; Galochkina, Anastasia V; Orshanskaya, Jana R; Zarubaev, Vladimir V; Shova, Sergiu; Enache, Cristian; Maganu, Maria

    2015-10-01

    New nucleoside analogues with an optically active bicyclo[2.2.1]heptane skeleton as sugar moiety and 6-substituted adenine were synthesized by alkylation of 6-chloropurine intermediate. Thymine and uracil analogs were synthesized by building the pyrimidine ring on amine 1. X-ray crystallography confirmed an exo-coupling of the thymine to the ring and an L configuration of the nucleoside analogue. The library of compounds was tested for their inhibitory activity against influenza virus A∖California/07/09 (H1N1)pdm09 and coxsackievirus B4 in cell culture. Compounds 13a and 13d are the most promising for their antiviral activity against influenza, and compound 3c against coxsackievirus B4. Compounds 3b and 3g were tested for anticancer activity. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Separation of toluene from n-heptane by liquid–liquid extraction using binary mixtures of [bpy][BF4] and [4bmpy][Tf2N] ionic liquids as solvent

    García, Silvia; Larriba, Marcos; García, Julián; Torrecilla, José S.; Rodríguez, Francisco

    2012-01-01

    Highlights: ► Binary mixtures of ionic liquids as extraction solvents of aromatics. ► [4bmpy][Tf 2 N] shows higher capacity but lower selectivity than sulfolane. ► [bpy][BF 4 ] shows lower capacity but higher selectivity than sulfolane. ► Mixed {[4bmpy][Tf 2 N] + [bpy][BF 4 ]} improves both extractive properties. - Abstract: The use of binary mixture of ionic liquids N-butylpyridinium tetrafluoroborate ([bpy][BF 4 ]), and 1-butyl-4-methylpyridinium bis(trifluoromethylsulfonyl)imide ([4bmpy][Tf 2 N]) in the liquid–liquid extraction of toluene from n-heptane has been investigated at 313.2 K and atmospheric pressure. The experimental capacity of extraction and selectivity for this binary mixture has proved to be intermediate to those corresponding to the pure ionic liquids, and they can be predicted using a logarithmic–linear model of solubility. Furthermore, the results showed that the use of binary mixture of {[bpy][BF 4 ] + [4bmpy][Tf 2 N]} at a mole solvent composition around 0.7 for [bpy][BF 4 ] improves both the capacity of extraction of toluene and the selectivity with respect to those of sulfolane, the organic solvent taken as a benchmark. Thus, this mixed ionic liquid could be likely to be used in the extraction of aromatic from aliphatic in replacement to sulfolane.

  4. Water-stable helical structure of tertiary amides of bicyclic β-amino acid bearing 7-azabicyclo[2.2.1]heptane. Full control of amide cis-trans equilibrium by bridgehead substitution.

    Hosoya, Masahiro; Otani, Yuko; Kawahata, Masatoshi; Yamaguchi, Kentaro; Ohwada, Tomohiko

    2010-10-27

    Helical structures of oligomers of non-natural β-amino acids are significantly stabilized by intramolecular hydrogen bonding between main-chain amide moieties in many cases, but the structures are generally susceptible to the environment; that is, helices may unfold in protic solvents such as water. For the generation of non-hydrogen-bonded ordered structures of amides (tertiary amides in most cases), control of cis-trans isomerization is crucial, even though there is only a small sterical difference with respect to cis and trans orientations. We have established methods for synthesis of conformationally constrained β-proline mimics, that is, bridgehead-substituted 7-azabicyclo[2.2.1]heptane-2-endo-carboxylic acids. Our crystallographic, 1D- and 2D-NMR, and CD spectroscopic studies in solution revealed that a bridgehead methoxymethyl substituent completely biased the cis-trans equilibrium to the cis-amide structure along the main chain, and helical structures based on the cis-amide linkage were generated independently of the number of residues, from the minimalist dimer through the tetramer, hexamer, and up to the octamer, and irrespective of the solvent (e.g., water, alcohol, halogenated solvents, and cyclohexane). Generality of the control of the amide equilibrium by bridgehead substitution was also examined.

  5. Experimental validation of a kinetic multi-component mechanism in a wide HCCI engine operating range for mixtures of n-heptane, iso-octane and toluene: Influence of EGR parameters

    Machrafi, Hatim

    2008-01-01

    The parameters that are present in exhaust gas recirculation (EGR) are believed to provide an important contribution to control the auto-ignition process of the homogeneous charge compression ignition (HCCI) in an engine. For the investigation of the behaviour of the auto-ignition process, a kinetic multi-component mechanism has been developed in former work, containing 62 reactions and 49 species for mixtures of n-heptane, iso-octane and toluene. This paper presents an experimental validation of this mechanism, comparing the calculated pressure, heat release, ignition delays and CO 2 emissions with experimental data performed on a HCCI engine. The validation is performed in a broad range of EGR parameters by varying the dilution by N 2 and CO 2 from 0 to 46 vol.%, changing the EGR temperature from 30 to 120 deg. C, altering the addition of CO and NO from 0 to 170 ppmv and varying the addition of CH 2 O from 0 to 1400 ppmv. These validations were performed respecting the HCCI conditions for the inlet temperature and the equivalence ratio. The results showed that the mechanism is validated experimentally in dilution ranges going up to 21-30 vol.%, depending on the species of dilution and over the whole range of the EGR temperature. The mechanism is validated over the whole range of CO and CH 2 O addition. As for the addition of NO, the mechanism is validated quantitatively up to 50 ppmv and qualitatively up to 170 ppmv

  6. The ignition delay, laminar flame speed and adiabatic temperature characteristics of n-pentane, n-hexane and n-heptane under O{sub 2}/CO{sub 2} atmosphere

    Zhao, Ran [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Wuhan Textile Univ. (China). School of Environment and Urban Construction; Liu, Hao; Zhong, Xiaojiao; Wang, Zijian; Jin, Ziqin; Qiu, Jianrong [Huazhong Univ. of Science and Technology, Wuhan (China). State Key Lab. of Coal Combustion; Chen, Yingming [Wuhan Textile Univ. (China). School of Environment and Urban Construction

    2013-07-01

    Oxy-fuel (O{sub 2}/CO{sub 2}) combustion is one of the several promising new technologies which can realize the integrated control of CO{sub 2}, SO{sub 2}, NO{sub X} and other pollutants. However, when fuels are burned in the high CO{sub 2} concentration environment, the combustion characteristics can be very different from conventional air-fired combustion. Such changes imply that the high CO{sub 2} concentration atmosphere has impacts on the combustion processes. In this paper, the ignition time, laminar flame speed and adiabatic temperature property of C{sub 5} {proportional_to} C{sub 7} n-alkane fuels were studied under both ordinary air atmosphere and O{sub 2}/CO{sub 2} atmospheres over a wide range of CO{sub 2} concentration in the combustion systems. A new unified detailed chemical kinetic model was validated and used to simulate the three liquid hydrocarbon fuel's flame characteristics. Based on the verified model, the influences of various parameters (atmosphere, excess oxygen ratio, O{sub 2} concentration, CO{sub 2} concentration, and alkane type) on the C{sub 5} {proportional_to} C{sub 7} n-alkane's flame characteristics were systematically investigated. It can be concluded that high CO{sub 2} concentration atmosphere has negative effect on n-pentane, n-hexane and n-heptane flame's ignition, laminar flame speed and adiabatic temperature. Besides, this work confirms that high CO{sub 2} concentration atmosphere's chemical effects play a pronounced role on the flame characteristics, especially for the ignition time property.

  7. Toxicological evaluation and metabolism of two N-alkyl benzamide umami flavour compounds: N-(heptan-4-ylbenzo[d][1,3]dioxole-5-carboxamide and (R-N-(1-methoxy-4-methylpentan-2-yl-3,4-dimethylbenzamide

    Donald S. Karanewsky

    Full Text Available Toxicological evaluations of two N-alkyl benzamide umami flavour compounds, N-(heptan-4-ylbenzo[d][1,3]dioxole-5-carboxamide (S807, CAS 745047-51-2 and (R-N-(1-methoxy-4-methylpentan-2-yl-3,4-dimethylbenzamide (S9229, CAS 851669-60-8, were completed for the purpose of assessing their safety for use in food and beverage applications. Both S807 and S9229 undergo rapid oxidative metabolism by both rat and human liver microsomes in vitro. In pharmacokinetic studies in rats, the systemic exposure to S9229 on oral administration is very low at all doses (% F < 1%, while that of S807 demonstrated a non-linear dose dependence. In metabolism studies in rats, hydroxylation of the C-4 aryl methyl group was found to be the dominant metabolic pathway for S9229. The dominant metabolic pathway for S807 in the rat involved oxidative scission of the methylenedioxy moiety to produce the corresponding 3,4-dihydroxybenamide which is further converted by Phase II metabolic enzymes to the 3- and 4-O-methyl ethers as well as their corresponding glucuronides. Both S807 and S9229 were not found to be mutagenic or clastogenic in vitro, and did not induce micronuclei in polychromatic erythrocytes in vivo. In a subchronic oral toxicity study in rats, the no-observed-effect-level (NOEL for S807 was 20 mg/kg bw/day when administered in the diet for 13 weeks. The no-observed-adverse-effect-level (NOAEL for S9229 in rats was 100 mg/kg bw/day (highest dose tested when administered in the diet for 28 consecutive days. Keywords: S807, S9229, FEMA GRAS, Subchronic toxicological evaluation, Genetic toxicological evaluation

  8. Experimental validation of a kinetic multi-component mechanism in a wide HCCI engine operating range for mixtures of n-heptane, iso-octane and toluene: Influence of EGR parameters

    Machrafi, Hatim [LGPPTS, Ecole Nationale Superieure de Chimie de Paris/ Universite Pierre et Marie Curie (Paris 6), 11, rue de Pierre et Marie Curie, 75231 Paris Cedex 05 (France)

    2008-11-15

    The parameters that are present in exhaust gas recirculation (EGR) are believed to provide an important contribution to control the auto-ignition process of the homogeneous charge compression ignition (HCCI) in an engine. For the investigation of the behaviour of the auto-ignition process, a kinetic multi-component mechanism has been developed in former work, containing 62 reactions and 49 species for mixtures of n-heptane, iso-octane and toluene. This paper presents an experimental validation of this mechanism, comparing the calculated pressure, heat release, ignition delays and CO{sub 2} emissions with experimental data performed on a HCCI engine. The validation is performed in a broad range of EGR parameters by varying the dilution by N{sub 2} and CO{sub 2} from 0 to 46 vol.%, changing the EGR temperature from 30 to 120 C, altering the addition of CO and NO from 0 to 170 ppmv and varying the addition of CH{sub 2}O from 0 to 1400 ppmv. These validations were performed respecting the HCCI conditions for the inlet temperature and the equivalence ratio. The results showed that the mechanism is validated experimentally in dilution ranges going up to 21-30 vol.%, depending on the species of dilution and over the whole range of the EGR temperature. The mechanism is validated over the whole range of CO and CH{sub 2}O addition. As for the addition of NO, the mechanism is validated quantitatively up to 50 ppmv and qualitatively up to 170 ppmv. (author)

  9. Study of thermodynamic and transport properties of binary liquid mixtures of n-decane with hexan-2-ol, heptan-2-ol and octan-2-ol at T = 298.15 K. Experimental results and application of the Prigogine–Flory–Patterson theory

    Mahajan, Aravind R.; Mirgane, Sunil R.

    2013-01-01

    Highlights: • The large positive V m E values are obtained for the binary mixtures at 298.15 K. • Excess isentropic compressibilities for the binary mixtures are positive over the whole composition range. • The values of G ∗E for all binary mixtures are negative over entire mole fraction. • Viscosities measured for the binary mixtures were correlated with values calculated by various viscosity models. • PEP theory, Bloomfield and Dewan model and Jouyban–Acree model are also used to correlate the experimental data. -- Abstract: Densities and viscosities of binary mixtures of n-decane with hexan-2-ol, heptan-2-ol and octan-2-ol have been measured over the entire range of composition at T = 298.15 K and at atmospheric pressure. From the experimental values of density and viscosity, the excess molar volumes (V m E ) and excess Gibbs energy of activation of viscous flow (G ∗E ) have been calculated. These results were fitted to Redlich–Kister polynomial equations to estimate the binary coefficients and standard errors. Jouyban–Acree model is used to correlate the experimental values of density, viscosity and ultrasonic velocity at T = 298.15 K. The results of the viscosity-composition are discussed in the light of various viscosity semi-empirical equations. The experimental results have been used to test the applicability of the Prigogine–Flory–Patterson (PFP) theory. The values of Δln η have also been analysed using Bloomfield and Dewan model. The experimental and calculated quantities are used to study the nature of mixing behaviour between the mixtures

  10. Excess Molar Volumes and Viscosities of Binary Mixtures of p-Xylene with Cyclohexane, n-Heptane, n-Octane,Sulfolane, N-Methyl-2-pyrrolidone and Acetic Acid at 303.15 K and 323.15 K and Atmospheric Pressure%对二甲苯与环己烷、正庚烷、正辛烷、环丁砜和N-甲基-2-吡咯烷酮和乙酸二元混合物在303.15K和323.15K的 超额体积和黏度

    杨长生; 马沛生; 周清

    2004-01-01

    Experimental data on density and viscosity at 303.15K and 323.15K are presented for the binary mixtures of p-xylene with cyclohexane, n-heptane, n-octane, sulfolane, N-methyl-2-pyrrolidone and acetic acid.From these data, the excess molar volume and deviations in viscosity have been calculated. The computed quantities have been fitted to the Redlich-Kister Equation to derive coefficients and estimate the standard error values. Results are discussed in terms of intermolecular interactions.

  11. Provisional Peer-Reviewed Toxicity Values for N-Heptane

    Provisional Peer-Reviewed Toxicity Values (PPRTV) assessments are developed for use by the Agency’s Office of Land and Emergency Management (OLEM) to support informed decisions in the Superfund program and at hazardous waste sites when a values is not available in the Integrated ...

  12. Modelling of heating and evaporation of n-Heptane droplets

    Yin, Chungen

    2015-01-01

    This study is a part of a project that is targeted to optimize the pyrolysis process of biomass pellets for bio-oil production and to develop new technology to upgrade the bio-oil for use in transportation. Among others, study of pyrolysis of the biomass pellets and evaporation of the pyrolysis bio...... and azimuthal directions, respectively, on each of which the flow, heat and mass transfer are numerically solved using the finite volume method. During the transient heating and evaporation process, the interaction between the moving droplets and free-stream flow are properly considered. Droplet dynamics...

  13. 2-[Anilino(phen-yl)meth-yl]cyclo-heptan-one.

    Eftekhari-Sis, Bagher; Mohajer, Sahar; Zirak, Maryam; Mozaffarnia, Sakineh; Büyükgüngör, Orhan

    2013-01-01

    In the title compound, C20H23NO, the cyclo-hepta-none ring adopts a twist-chair conformation, with the amino-methyl substituent in an equatorial position. The relative configuration of the two stereocenters is R,R. In the crystal, mol-ecules are linked by N-H⋯O hydrogen bonds into chains along [100].

  14. Ternary liquid-liquid equilibria for mixtures of toluene + n-heptane + an ionic liquid

    Meindersma, G.W.; Podt, J.G.; de Haan, A.B.

    2006-01-01

    This research has been focused on a study of sulfolane and four ionic liquids as solvents in liquid–liquid extraction. Liquid–liquid equilibria data were obtained for mixtures of (sulfolane or 4-methyl-N-butylpyridinium tetrafluoroborate ([mebupy]BF4) or 1-ethyl-3-methylimidazolium ethylsulfate

  15. Excess Molar Volumes of the Heptane ů 1-Chloropentane System at High Pressures and Elevated Temperatures

    Linek, Jan; Morávková, Lenka

    2001-01-01

    Roč. 55, č. 6 (2001), s. 382-385 ISSN 0366-6352. [28th International Conference of SSCHE. Tatranské Matliare, 21.05.2001-25.05.2001] R&D Projects: GA ČR GA203/00/0600 Institutional research plan: CEZ:AV0Z4072921 Keywords : measurement * excess molar volumes * apparatus Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.349, year: 2001

  16. 2-[Anilino(phen­yl)meth­yl]cyclo­heptan­one

    Eftekhari-Sis, Bagher; Mohajer, Sahar; Zirak, Maryam; Mozaffarnia, Sakineh; Büyükgüngör, Orhan

    2013-01-01

    In the title compound, C20H23NO, the cyclo­hepta­none ring adopts a twist-chair conformation, with the amino­methyl substituent in an equatorial position. The relative configuration of the two stereocenters is R,R. In the crystal, mol­ecules are linked by N—H⋯O hydrogen bonds into chains along [100]. PMID:23476371

  17. ADAPTATION OF N-HEPTANE AUTOIGNITION TABULATION FOR COMPLEX CHEMISTRY MECHANISMS

    Neven Duić

    2011-01-01

    Full Text Available The adaptation of auto-ignition tabulation for effective use of complex chemical mechanisms will be presented in this paper. Taking cool flame ignition phenomenon into account could improve numerical simulations of combustion in compression ignition engines. Current approaches of successful simulation of this phenomenon are based on the extraction of ignition delay times, heat releases and also reaction rates from tabulated data dependant on four parameters: temperature, pressure, equivalence ratio and exhaust gasses mass fraction. The methods described here were used to create lookup tables including cool flame using a comprehensive chemical mechanism without including reaction rates data (as used by other authors. The method proved to be stable for creating tables and these results will be shown, as well as initial implementation results using the tables in computational fluid dynamics software.

  18. 2,2′-[1,1′-(Heptane-1,7-diyldioxydinitrilodiethylidyne]di-1-naphthol

    Wen-Kui Dong

    2009-07-01

    Full Text Available The molecule of the title compound, C31H34N2O4, adopts an L-shaped configuration, in which the naphthalene units are approximately perpendicular, making a dihedral angle of 87.89 (3°. Intramolecular H-bonds are formed between the OH substituents and the N atoms at each end of the molecule. In the crystal structure, each molecule links six other molecules into an infinite three-dimensional network supramolecular structure, which is built from one-dimensional zigzag chains via weak C—H...π stacking and intermolecular C—H...O hydrogen bonds.

  19. Modeling Frequency Response of Photoacoustic Cells using FEM for Determination of N-heptane Contamination in Air: Experimental Validation

    Duggen, Lars; Albu, Mihaela; Willatzen, Morten

    2012-01-01

    We briefly present the basic principle of the photoacoustic effect in gases. We present the equations and boundary conditions governing the acoustic field generated by the absorption of a modulated laser beam. We solve these equations using Finite Element Methods and compare the results with expe...

  20. Modeling Ignition of a Heptane Isomer: Improved Thermodynamics, Reaction Pathways, Kinetic, and Rate Rule Optimizations for 2-Methylhexane

    Mohamed, Samah; Cai, Liming; Khaled, Fathi; Banyon, Colin; Wang, Zhandong; Rachidi, Mariam El; Pitsch, Heinz; Curran, Henry J.; Farooq, Aamir; Sarathy, Mani

    2016-01-01

    Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important to investigate the combustion behavior of real fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracies in certain portions of the models. This study focuses on updating thermodynamic data and the kinetic reaction mechanism for a gasoline surrogate component, 2-methylhexane, based on recently published thermodynamic group values and rate rules derived from quantum calculations and experiments. Alternative pathways for the isomerization of peroxy-alkylhydroperoxide (OOQOOH) radicals are also investigated. The effects of these updates are compared against new high-pressure shock tube and rapid compression machine ignition delay measurements. It is shown that rate constant modifications are required to improve agreement between kinetic modeling simulations and experimental data. We further demonstrate the ability to optimize the kinetic model using both manual and automated techniques for rate parameter tunings to improve agreement with the measured ignition delay time data. Finally, additional low temperature chain branching reaction pathways are shown to improve the model’s performance. The present approach to model development provides better performance across extended operating conditions while also strengthening the fundamental basis of the model.

  1. A comparative study of the oxidation characteristics of two gasoline fuels and an n-heptane/iso-octane surrogate mixture

    Javed, Tamour; Nasir, Ehson F.; Es-sebbar, Et-touhami; Farooq, Aamir

    2015-01-01

    Ignition delay times and CO, H2O, OH and CO2 time-histories were measured behind reflected shock waves for two FACE (Fuels for Advanced Combustion Engines) gasolines and one PRF (Primary Reference Fuel) blend. The FACE gasolines chosen for this work

  2. A comparative study of the oxidation characteristics of two gasoline fuels and an n-heptane/iso-octane surrogate mixture

    Javed, Tamour

    2015-01-01

    Ignition delay times and CO, H2O, OH and CO2 time-histories were measured behind reflected shock waves for two FACE (Fuels for Advanced Combustion Engines) gasolines and one PRF (Primary Reference Fuel) blend. The FACE gasolines chosen for this work are primarily paraffinic and have the same octane rating (∼RON = 84) as the PRF blend, but contain varying amounts of iso- and n-paraffins. Species time-histories and ignition delay times were measured using laser absorption methods over a temperature range of 1350-1550 K and pressures near 2 atm. Measured species time-histories and ignition delay times of the PRF blend and the two FACE fuels agreed reasonably well. However, when compared to recent gasoline surrogate mechanisms, the simulations did not capture some of the kinetic trends found in the species profiles. To our knowledge, this work provides some of the first shock tube species time-history data for gasoline fuels and PRF surrogates and should enable further improvements in detailed kinetic mechanisms of gasoline fuels.

  3. rac-(1S,6S)-Methyl 6-methyl-2-oxobicyclo[4.1.0]heptane-1-carboxylate

    Juhl, Martin; Søtofte, Inger

    2007-01-01

    The crystal structure of the title compound, C10H14O3, was investigated as part of a study of the chemistry of nucleophilic 1,4-additions to highly electrophilic C=C double bonds. The cyclohexane ring adopts a half-chair conformation. The crystal packing is stabilized by van der Waals forces....

  4. Pervaporation Membranes with Poly(γ-Benzyl-L-Glutamate) Selective Layers for Separation of Toluene - n-Heptane Mixtures

    Kononova, S.V.; Kremnev, R.V.; Suvorova, E.I.; Baklagina, Y.G.; Volchek, B.Z.; Uchytil, Petr; Shabsels, B.M.; Romashkova, K.A.; Setničková, Kateřina; Řezníčková Čermáková, Jiřina

    2015-01-01

    Roč. 477, MAR 1 (2015), s. 14-24 ISSN 0376-7388 Institutional support: RVO:67985858 Keywords : composite membrane * structure * hydrocarbons pervaporation Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 5.557, year: 2015

  5. Modeling Frequency Response of Photoacoustic Cells using FEM for Determination of N-heptane Contamination in Air: Experimental Validation

    Lars Duggen

    2012-04-01

    Full Text Available We briefly present the basic principle of the photoacoustic effect in gases. We present the equations and boundary conditions governing the acoustic field generated by the absorption of a modulated laser beam. We solve these equations using Finite Element Methods and compare the results with experiment. We find that apparently there are effects not taken into account in the classic acoustic theory as we find a larger damping than theory predicts. However, we see that these effects have significant negative influence on the quality factor of the cell and thereby the performance limit.

  6. Laser-induced-fluorescence imaging of NO in a eta-heptane- and diesel-fuel-driven diesel engine

    Brugman, T.M.; Klein-Douwel, R.J.H.; Huigen, G.; Walwijk, van E.; Meulen, ter J.J.

    1993-01-01

    Continuous on-line imaging by 2D-LIF techniques of in-cylinder NO distributions in a running Diesel engine is explored using an ArF-excimer laser at 193 nm operating at low power. For the first time NO excitation spectra could be measured as a result of high optical transparencies during

  7. Modeling Ignition of a Heptane Isomer: Improved Thermodynamics, Reaction Pathways, Kinetic, and Rate Rule Optimizations for 2-Methylhexane

    Mohamed, Samah

    2016-03-21

    Accurate chemical kinetic combustion models of lightly branched alkanes (e.g., 2-methylalkanes) are important to investigate the combustion behavior of real fuels. Improving the fidelity of existing kinetic models is a necessity, as new experiments and advanced theories show inaccuracies in certain portions of the models. This study focuses on updating thermodynamic data and the kinetic reaction mechanism for a gasoline surrogate component, 2-methylhexane, based on recently published thermodynamic group values and rate rules derived from quantum calculations and experiments. Alternative pathways for the isomerization of peroxy-alkylhydroperoxide (OOQOOH) radicals are also investigated. The effects of these updates are compared against new high-pressure shock tube and rapid compression machine ignition delay measurements. It is shown that rate constant modifications are required to improve agreement between kinetic modeling simulations and experimental data. We further demonstrate the ability to optimize the kinetic model using both manual and automated techniques for rate parameter tunings to improve agreement with the measured ignition delay time data. Finally, additional low temperature chain branching reaction pathways are shown to improve the model’s performance. The present approach to model development provides better performance across extended operating conditions while also strengthening the fundamental basis of the model.

  8. Autoignited and non-autoignited lifted flames of pre-vaporized n-heptane in coflow jets at elevated temperatures

    Choi, Sangkyu; Chung, Suk-Ho

    2013-01-01

    without any external ignition source. Autoignited lifted flames with both tribrachial edges and mild combustion characteristics were observed. The correlation of the liftoff height with the calculated adiabatic ignition delay time was weak, unlike in cases

  9. Co-current and Counter-Current Operations for Steam Reforming of Heptane in a Novel CFB Membrane Reformer

    Chen, Z.; Elnashaie, S.S.E.H.

    2004-01-01

    Hydrogen production by steam reforming of higher hydrocarbon over nickel supported catalyst is investigated in an earlier suggested novel Circulating Fast Fluidized Bed Membrane Reformer (CFFBMR). Palladium hydrogen membranes are used with co-current and counter-current operation modes. It is found that hydrogen production has a non-monotonic dependence upon the reaction temperature in the range of 623-823 K. Between 623 and 723 K. the yields of hydrogen decrease and then increase between 723 and 823 K. This important phenomenon is investigated, discussed and explained. The simulation results shows that the reformer performance can be significantly improved using hydrogen membranes, especially in the counter-current operation mode. At low temperatures around 623 K, both .co-current and counter-current operation modes provide similar yields of hydrogen. While at temperature 723 K and higher, the counter-current operation provides the highest yield of hydrogen

  10. Carbon-based nanomaterial synthesis using nanosecond electrical discharges in immiscible layered liquids: n-heptane and water

    Hamdan, Ahmad; Cha, Min

    2018-01-01

    Plasmas in- or in-contact with liquids have been extensively investigated due to their high potential for a wide range of applications including but not limited to, water treatment, material synthesis and functionalization, bio-medical applications

  11. A methodology to relate octane numbers of binary and ternary n-heptane, iso-octane and toluene mixtures with simulated ignition delay times

    Badra, Jihad A.; Bokhumseen, Nehal; Mulla, Najood; Sarathy, Mani; Farooq, Aamir; Kalghatgi, Gautam; Gaillard, Patrick

    2015-01-01

    , are correlated with a fundamental chemical kinetic parameter, specifically, homogeneous gas-phase fuel/air ignition delay time. Ignition delay times for stoichiometric fuel/air mixtures are calculated at various constant volume conditions (835 K and 20 atm, 825 K

  12. New spiro (thio barbiturates based on cyclohexanone and bicyclo [3.1.1]heptan-6-one by nonconcerted [1+5] cycloaddition reaction and their conformational structures

    N. N. Pesyan

    2014-09-01

    Full Text Available Crossed-aldol condensation reaction of aromatic aldehydes with ketones such as; acetone and cyclohexanone leads to the efficient formation of cross conjugated α,β-unsaturated ketones in excellent yield. The intermolecular and then intramolecular Michael addition reaction of α,β-unsaturated ketones derived from acetone and cyclohexanone with (thiobarbituric acids lead to synthesis new type of 7,11-diaryl-2,4-diazaspiro[5.5]undecane-1,3,5,9-tetraone and 2,4-diaryl-1'H-spiro[bicyclo[3.3.1]nonane-3,5'-pyrimidine]-2',4',6',9(3'H-tetraone, respectively in good yield. Structure elucidation is carried out by 1H NMR, 13C NMR, FT-IR, UV-Visible, mass spectroscopy and X-ray crystallography techniques. A possible mechanism of the formation is discussed. The structural conformation also demonstrated by coupling constants derived from dihedral angles between vicinal and geminal protons. The 1H NMR spectra of NH protons of spiro compounds derived from barbituric acid show a broad singlet peak instead, these protons in the spiro compounds derived from thiobarbituric acid show two distinct peaks. DOI: http://dx.doi.org/10.4314/bcse.v28i3.12

  13. Extraction of gold(III) from hydrochloric acid solutions by CTAB/n-heptane/iso-amyl alcohol/Na{sub 2}SO{sub 3} microemulsion

    Lu Wenjuan; Lu Yanmin; Liu Fei; Shang Kai; Wang Wei [Key Laboratory for Special Functional Aggregated Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China); Yang Yanzhao, E-mail: yzhyang@sdu.edu.cn [Key Laboratory for Special Functional Aggregated Materials of Education Ministry, School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100 (China)

    2011-02-28

    The extraction of Au(III) from hydrochloric acid solutions by microemulsion was studied. The extraction experiments were carried out using cetyltrimethylammonium bromide (CTAB) as surfactant and iso-amyl alcohol as co-surfactant. Au(III) was found to be extracted into the microemulsion phase due to ion pair formation such as AuCl{sub 4}{sup -}CTAB{sup +}. The influence of temperature on the extraction of Au(III) has been investigated at temperatures ranging from 288 to 313 K. Temperature was found to decrease the distribution of Au(III). Thermodynamic parameters like enthalpy and entropy of the extraction, calculated by applying Van't Hoff equation, were -36.76 kJ mol{sup -1} and -84.87 J mol{sup -1} K{sup -1}, respectively. Furthermore, the influence of the concentrations of hydrogen ion and chloride anion on the extraction efficiency (E%) were verified. Au(III) was extracted quantitatively (E% > 99%) and selectively at the whole range of HCl concentrations (0.2-5 M). Recovery of gold from electrical waste and treatment of CTAB wastewater generated from the extraction were also discussed. Thus, the extraction of Au(III) from hydrochloric acid solutions by microemulsion is an effective approach.

  14. Excess Molar Volumes of the (Cyclohexane + Pentane, or Hexane, or Heptane, or Octane, or Nonane) Systems at Temperature 298.15 K

    Balán, J.; Morávková, Lenka; Linek, Jan

    2007-01-01

    Roč. 61, č. 6 (2007), s. 497-501 ISSN 0366-6352 R&D Projects: GA ČR(CZ) GA104/06/0656 Institutional research plan: CEZ:AV0Z40720504 Keywords : hydrocarbon * density * excess volume Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.367, year: 2007

  15. Stereochemistry and mechanism of the reduction of some bicyclo (2-2-1-) heptane-2-ones by metals dissolved in liquid ammonia

    Coulombeau, A.

    1969-01-01

    A systematic experimental study of the reduction of four bicyclo(2-2-1)hepta n-2-ones by dissolved alkaline and alkaline-earth metals in liquid ammonia is reported. Chapter one: models of metal-ammonia solutions and mechanisms of the reduction of ketones by these solutions are rapidly recalled. Chapter two: results obtained in the thermodynamic equilibration of three pairs of epimeric alcohols which formally derive from three of the starting ketones are presented. Chapter three: deals with the results obtained in the reduction of the ketones in the absence or the presence of a proton source. A new interpretation of these results is given and is based upon two different effects: - the torsional interaction created by the bridgehead substituent on the C-O bond which favours the formation of the endo alcohol; - the difference of steric hindrance between the two sides (exo and endo) defined by the plane of the carbonyl group of the starting molecule, which favours the attack of the metal cation from one side or the other, and therefore the formation of the exo or the endo epimer. This mechanism is generalised in a model which is tested by means of some examples published in the literature. It then appears able to construe correctly the obtained results. (author) [fr

  16. Product shape selectivity of MFI-type, MEL-type, and BEA-type zeolites in the catalytic hydroconversion of heptane

    Poursaeidesfahani, A.; de Lange, M.F.; Khodadadian, F.; Dubbeldam, D.; Rigutto, Marcello; Nair, Nitish; Vlugt, T.J.H.

    2017-01-01

    The influence of product shape selectivity on the bifunctional conversion of n-C7 by zeolite catalysts is investigated. Three different zeolite catalysts with different pore sizes (MFI-type, MEL-type, and BEA-type zeolites) have been investigated experimentally. For all three

  17. Effect of Temperature, Pressure and Equivalence Ratio on Ignition Delay in Ignition Quality Tester (IQT): Diesel,n-Heptane, andiso-Octane Fuels under Low Temperature Conditions

    Yang, Seung Yeon; Naser, Nimal; Chung, Suk-Ho; Cha, Junepyo

    2015-01-01

    -octane in relatively low temperature conditions to simulate unsteady spray ignition behavior. A KAUST Research ignition quality tester (KR-IQT) was utilized, which has a feature of varying temperature, pressure and equivalence ratio using a variable displacement fuel

  18. Auto-Ignition and Spray Characteristics of n-Heptane and iso-Octane Fuels in Ignition Quality Tester

    Jaasim, Mohammed; Elhagrasy, Ayman; Sarathy, Mani; Chung, Suk-Ho; Im, Hong G.

    2018-01-01

    breakup models, namely the Kelvin-Helmholtz/Rayleigh-Taylor (KH-RT) and linearized instability sheet atomization (LISA) models, in terms of their influence on auto-ignition predictions. Two spray models resulted in different local mixing

  19. Using graphene/styrene-isoprene-styrene copolymer composite thin film as a flexible microstrip antenna for the detection of heptane vapors

    Olejnik, Robert; Matyas, Jiri; Slobodian, Petr; Riha, Pavel

    2018-03-01

    Most portable devices, such as mobile phones or tablets, use antennas made of copper. This paper demonstrates the possible use of antenna constructed from electrically conductive polymer composite materials for use in those applications. The method of preparation and the properties of the graphene/styrene-isoprene-styrene copolymer as flexible microstrip antenna are described in this contribution. Graphene/styrene-isoprene-styrene copolymer toluene solution was prepared by means of ultrasound and the PET substrate was dip coated to reach a fine thin film. The main advantages of using PET as a substrate are low weight and flexibility. The final size of the flexible microstrip antenna was 10 × 25 mm with thickness of 0.48 mm (PET substrate 0.25 mm) with a weight of 0.110 g. The resulting antenna operates at a frequency of 1.8 GHz and gain ‑40.02 dB.

  20. Excess enthalpies of binary and ternary mixtures containing dibutyl ether (DBE), 1-butanol, and heptane at T = 298.15 K and 313.15 K

    Aguilar, Fernando; Alaoui, Fatima E.M. [Departamento de Ingenieria Electromecanica, Escuela Politecnica Superior, Universidad de Burgos, E-09006 Burgos (Spain); Segovia, Jose J.; Villamanan, Miguel A. [Grupo de Termodinamica y Calibracion TERMOCAL, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Montero, Eduardo A., E-mail: emontero@ubu.e [Departamento de Ingenieria Electromecanica, Escuela Politecnica Superior, Universidad de Burgos, E-09006 Burgos (Spain)

    2010-01-15

    Experimental excess molar enthalpies of the ternary systems left bracedibutyl ether (DBE) + 1-butanol + heptaneright brace and the corresponding binary systems at T = 298.15 K and T = 313.15 K at atmospheric pressure are reported. A quasi-isothermal flow calorimeter has been used to make the measurements. All the binary and the ternary systems show endothermic character. The experimental data for the binary and ternary systems have been fitted using the Redlich-Kister equation, the NRTL and UNIQUAC models. The values of the standard deviation indicate good agreement between the experimental results and those calculated from the equations.

  1. Electrodeposition of Asphaltenes. 2. Effect of Resins and Additives

    Khvostichenko, Daria S; Andersen, Simon Ivar

    2010-01-01

    Electrodeposition of asphaltenes from oil/heptane, asphaltene/heptane, and asphaltene/heptane/additive mixtures has been investigated. Toluene, native petroleum resins, and a synthetic asphaltene dispersant, p-nonylphenol, were used as additives. The addition of these components led to partial...... dissolution of asphaltenes in heptane. The charge of asphaltenic particles was found to be negative in oil/heptane mixtures and positive in asphaltene/heptane mixtures. In asphaltene/heptane/toluene systems, the charge of the deposit varied from positive to neutral to negative, depending upon the method...

  2. CCDC 1449342: Experimental Crystal Structure Determination : (1,3-bis(2,6-bis(heptan-4-yl)phenyl)-2,3-dihydro-1H-imidazol-2-ylidene)-(4-chlorobenzoato)-silver(i) dichloromethane solvate

    Wong, Valerie H. L.; Vummaleti, Sai V. C.; Cavallo, Luigi; White, Andrew J. P.; Nolan, Steven P.; Hii, King Kuok (Mimi)

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from

  3. Impact of dopant metal ions in the framework of parent zirconia on the n-heptane isomerization activity of the Pt/WO3-ZrO2 catalysts

    Kaucký, Dalibor; Sobalík, Zdeněk; Hidalgo, J. M.; Černý, R.; Bortnovský, O.

    2016-01-01

    Roč. 420, AUG 2016 (2016), s. 107-114 ISSN 0304-5102 R&D Projects: GA MPO FR-TI3/316 Institutional support: RVO:61388955 Keywords : zirconia * tungstated zirconia * dopants Subject RIV: CF - Physical ; Theoretical Chemistry

  4. CCDC 1449342: Experimental Crystal Structure Determination : (1,3-bis(2,6-bis(heptan-4-yl)phenyl)-2,3-dihydro-1H-imidazol-2-ylidene)-(4-chlorobenzoato)-silver(i) dichloromethane solvate

    Wong, Valerie H. L.

    2016-01-01

    An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  5. (3-Benzoyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-olato-κ2O,Obis[2-(2-pyridylphenyl-κ2C1,N]iridium(III

    Kaijun Luo

    2011-11-01

    Full Text Available The title compound, [Ir(C11H8N2(C17H19O2], has an octahedral coordination geometry around the IrIII atom, retaining the cis-C,C,trans–N,N chelate disposition of the two 2-phenylpyridine ligands. The chelate rings are nearly mutually perpendicular [the interplanar angles range from 85.48 (17 to 89.17 (19°]. The two 2-(2-pyridylphenyl ligands are approximately planar, with the plane of the phenyl ring being inclined to that of the pyridine ring by 2.3 (3 and 5.1 (3° in the two ligands. The interplanar angle between the phenyl ring in 3-benzoyl-camphor and the IrO2C3 chelate ring is 35.5 (2°.

  6. X-ray mapping in heterocyclic design: 18. X-ray diffraction study of a series of derivatives of 3-cyanopyridine-2-one with annelated heptane and octane cycles

    Rybakov, V. B., E-mail: Rybakov20021@yandex.ru; Babaev, E. V. [Moscow State University, Faculty of Chemistry (Russian Federation); Paronikyan, E. G., E-mail: Ervand.paronikyan@mail.ru [National Academy of Sciences of Armenia, Mnjoyan Institute of Fine Organic Chemistry, Scientific Technological Center of Organic and Pharmaceutical Chemistry (Armenia)

    2017-03-15

    Seven new, previously unknown, bicyclic and tricyclic heterocycles based on derivatives of 3-cyanopyrid-2-ones are obtained: 2-oxo-2,5,6,7,8,9-hexahydro-1H-cyclohepta[b]pyridine-3-carbonitrile, C{sub 11}H{sub 12}N{sub 2}O (1a); 2-[2-(4-chlorophenyl)-2-oxoethoxy]-6,7,8,9-tetrahydro-5H-cyclohepta[b] pyridine-3-carbonitrile, C{sub 19}H{sub 17}ClN{sub 2}O{sub 2} (2a); (3-amino-6,7,8,9-tetrahydro-5H-cyclohepta[b]furo[3,2-e]pyridin-2-yl)(4- chlorophenyl)methanone, C{sub 19}H{sub 17}ClN{sub 2}O{sub 2} (3); 2-oxo-1,2,5,6,7,8,9,10-octahydrocycloocta[b]pyridine-3-carboxamide, C{sub 12}H{sub 16}N{sub 2}O{sub 2} (4); 2-[2-(4-chorophenyl)-2-oxoethoxy]-5,6,7,8,9,10 -hexahydrocycloocta[b]pyridine-3-carboxamide, C{sub 20}H{sub 21}ClN{sub 2}O{sub 3} (5a); 1-[2-(4-chlorophenyl)-2-oxoethyl]-2-oxo-1,2,5,6,7,8,9,10 -octahydrocycloocta[b]pyridine-3-carboxamide, C{sub 20}H{sub 21}ClN{sub 2}O{sub 3} (5b); and 2-[2-(4-chlorophenyl)-2-oxoethoxy]-5,6,7,8,9,10-hexahydrocycloocta[b] pyridine-3-carbonitrile, C{sub 20}H{sub 19}ClN{sub 2}O{sub 2}, (6). All compounds are characterized by {sup 1}H NMR spectroscopy, and their crystal structures are determined by X-ray diffraction.

  7. Solid–liquid equilibria for binary and ternary systems with the Cubic-Plus-Association (CPA) equation of state

    Fettouhi, André; Thomsen, Kaj

    2010-01-01

    A systematic investigation of the CPA model's performance within solid-liquid equilibria (SLE) in binary mixtures (methane + ethane, methane + heptane, methane + benzene, methane + CO2, ethane + heptane, ethane + CO2, 1-propanol + 1,4-dioxane, ethanol + water, 2-propanol + water) is presented. Th....... The results from the binary mixtures are used to predict SLE behaviour in ternary mixtures (methane + ethane + heptane, methane + ethane + CO2). Our results are compared with experimental data found in the literature....

  8. Stereochemistry and mechanism of the reduction of some bicyclo (2-2-1-) heptane-2-ones by metals dissolved in liquid ammonia; Stereochimie et mecanisme de la reduction de quelques bicyclo (2-2-1) heptanones-2 par les metaux dissous dans l'ammoniac liquide

    Coulombeau, A [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

    1969-07-01

    A systematic experimental study of the reduction of four bicyclo(2-2-1)hepta n-2-ones by dissolved alkaline and alkaline-earth metals in liquid ammonia is reported. Chapter one: models of metal-ammonia solutions and mechanisms of the reduction of ketones by these solutions are rapidly recalled. Chapter two: results obtained in the thermodynamic equilibration of three pairs of epimeric alcohols which formally derive from three of the starting ketones are presented. Chapter three: deals with the results obtained in the reduction of the ketones in the absence or the presence of a proton source. A new interpretation of these results is given and is based upon two different effects: - the torsional interaction created by the bridgehead substituent on the C-O bond which favours the formation of the endo alcohol; - the difference of steric hindrance between the two sides (exo and endo) defined by the plane of the carbonyl group of the starting molecule, which favours the attack of the metal cation from one side or the other, and therefore the formation of the exo or the endo epimer. This mechanism is generalised in a model which is tested by means of some examples published in the literature. It then appears able to construe correctly the obtained results. (author) [French] Une etude experimentale systematique de la reduction de quatre bicyclo-(2-2-1)heptanones-2 par les metaux alcalins et alcalino-terreux dissous dans l'ammoniac liquide a ete effectuee. 1er chapitre: on y rappelle rapidement les modeles proposes pour la structure des solutions metalliques dans l'ammoniac liquide, ainsi que les mecanismes de reduction des cetones par ces solutions. 2eme chapitre: on y presente les resultats obtenus lors de l'equilibration thermodynamique de trois couples d'alcools epimeres derivant de trois des cetones reduites. 3eme chapitre: il concerne les resultats obtenus lors de la reduction des cetones en l'absence ou en presence de donneurs de protons. Une interpretation nouvelle de ces resultats est donnee, fondee sur deux effets differents: - l'interaction de torsion creee par le substituant en tete de pont sur la liaison C-O et favorisant la formation de l'alcool endo; - la difference d'encombrement entre les deux cotes exo et endo, definis par le plan du carbonyle de la molecule initiale, favorisant la formation de l'alcool endo ou de l'alcool exo. Ce mecanisme est generalise sous forme d'un modele qui est alors mis a l'epreuve de quelques exemples pris dans la litterature. Il se revele alors susceptible d'interpreter correctement les resultats obtenus. (auteur)

  9. A reaction mechanism for gasoline surrogate fuels for large polycyclic aromatic hydrocarbons

    Raj, Abhijeet; Charry Prada, Iran David; Amer, Ahmad Amer; Chung, Suk-Ho

    2012-01-01

    This work aims to develop a reaction mechanism for gasoline surrogate fuels (n-heptane, iso-octane and toluene) with an emphasis on the formation of large polycyclic aromatic hydrocarbons (PAHs). Starting from an existing base mechanism for gasoline

  10. Application of lipid peroxidation and protein oxidation biomarkers for oxidative damage in mammalian cells. A comparison with two fluorescent probes

    Orhan, H.; Gurer-Orhan, H.; Vriese, E.; Vermeulen, N.P.E.; Meerman, J.H.N.

    2006-01-01

    We recently developed two biomarker sets for oxidative damage: one for determination of lipid peroxidation (LPO) degradation products; acetaldehyde, propanal, butanal, pentanal, hexanal, heptanal, octanal, nonanal, malondialdehyde and acetone, by a gas chromatography-electron capture detection

  11. The Evaporation of Liquid Droplets in Highly Turbulent Gas Streams

    Gould, Richard

    1998-01-01

    Single acetone and heptane droplets were suspended from a hypodermic needle in turbulent airflow, and the Nusselt number was obtained from direct measurements of the droplet diameter and evaporation rate...

  12. On the controlling mechanism of the upper turnover states in the NTC regime

    Ji, Weiqi; Zhao, Peng; He, Tanjin; He, Xin; Farooq, Aamir; Law, Chung K.

    2015-01-01

    Using n-butane, n-heptane and iso-octane as representative fuels exhibiting NTC (negative temperature coefficient) behavior, comprehensive computational studies with detailed mechanisms and theoretical analysis were performed to investigate

  13. Separation of Nitration By-Products in Commercial-Grade Trinitro-Toluene by High Performance Liquid Chromatography.

    1982-06-01

    Columns Columns used were:- Alltech 10 micron Silica 250 mm x 4.6 - I.D. Alltech 10 micron C18 Reverse-Phase 250 a x 4.6 mm I.D. Excalibar 10 micron...column with dichloromethane/n-heptane eluent. Ethyl acetate/n-heptane eluent has the advantage that it does not require flushing out at the end of each

  14. Applications of Laser Diagnostics

    2005-03-01

    fraction of methane in the fuel is 0.48. The steady nozzle velocities of the fuel and oxyder stream are respectively 0.59 m/s and 0.61 m/s. The...Hexane Heptane Toluene Benzene THF Ethyl acetate Chloroform Dichloromethane Acetone DMSO Propylene carbonate Benzyl alcohol Ethanol Methanol Octanol...Cyclohexane Pentane Hexane Heptane Toluene Benzene THF Ethyl acetate Chloroform Dichloromethane Acetone DMSO Propylene carbonate Benzyl alcohol Ethanol

  15. Push-Pull Effects of Three Plant Secondary Metabolites on Oviposition of the Potato Tuber Moth, Phthorimaea operculella

    Ma, Y.F.; Xiao, C.

    2013-01-01

    The push-pull effects of three plant secondary metabolites, azadirachtin, eucalyptol, and heptanal, on the oviposition choices of potato tubers by the potato tuber moth, Phthorimaea operculella (Zeller) (Lepidoptera: Gelechiidae) were tested in the laboratory. Azadirachtin at concentrations from 1.5 to 12 mg/L had a significant repellent effect on oviposition. Eucalyptol at concentrations from 3 to 12 mg/L promoted oviposition. Heptanal promoted oviposition at low concentrations from 0.1875 to 3.0 mg/L but repelled it at higher concentrations from 12 to 24 mg/L. The combination of azadirachtin (12 mg/L) with eucalyptol (3.0 mg/L) resulted in a significant pushpull effect of 56.3% on oviposition. The average maximum push-pull effects occurred with the combinations of azadirachtin with heptanal (12 and 0.375 mg/L, respectively; 38.7% push-pull effect), heptanal with eucalyptol (12 and 6 mg/L, respectively; 31.4% push-pull effect), and heptanal (high concentration) with heptanal (low concentration) (12.0 and 0.375 mg/L, respectively; 25% push-pull effect). PMID:24786822

  16. Use of limonene in countercurrent chromatography: a green alkane substitute.

    Faure, Karine; Bouju, Elodie; Suchet, Pauline; Berthod, Alain

    2013-05-07

    Counter-current chromatography (CCC) is a preparative separation technique working with the two liquid phases of a biphasic liquid system. One phase is used as the mobile phase when the other, the stationary phase, is held in place by centrifugal fields. Limonene is a biorenewable cycloterpene solvent coming from orange peel waste. It was evaluated as a possible substitute for heptane in CCC separations. The limonene/methanol/water and heptane/methanol/water phase diagrams are very similar at room temperature. The double bonds of the limonene molecule allows for possible π-π interactions with solutes rendering limonene slightly more polar than heptane giving small differences in solute partition coefficients in the two systems. The 24% higher limonene density is a difference with heptane that has major consequences in CCC. The polar and apolar phases of the limonene/methanol/water 10/9/1 v/v have -0.025 g/cm(3) density difference (lower limonene phase) compared to +0.132 g/cm(3) with heptane (upper heptane phase). This precludes the use of this limonene system with hydrodynamic CCC columns that need significant density difference to retain a liquid stationary phase. It is an advantage with hydrostatic CCC columns because density difference is related to the working pressure drop: limonene allows one to work with high centrifugal fields and moderate pressure drop. Limonene has the capability to be a "green" alternative to petroleum-based solvents in CCC applications.

  17. Antiplasticization and plasticization of Matrimid® asymmetric hollow fiber membranes—Part A. Experimental

    Lee, Jong Suk

    2010-03-15

    The complex effects of highly sorbing feed gas contaminants such as toluene and n-heptane on performance of both annealed and non-annealed Matrimid® asymmetric fibers relevant to CO2/CH4 separation are reported. Membrane performance was quantified both during contaminant exposure and after removal of the contaminant from the feed stream. Exposure to either toluene or n-heptane during permeation reduces carbon dioxide permeance and the carbon dioxide/methane selectivity in non-annealed fibers. After exchange with a contaminant-free feed containing only CO2 and CH4 mixed gas, the carbon dioxide permeance and carbon dioxide/methane selectivity were affected, indicating a glassy state conditioning effect due to the prior contaminant exposure. Interestingly, the conditioning effect after simultaneous exposure to toluene and n-heptane (284 ppm toluene and 504 ppm n-heptane) was less than the conditioning observed for either toluene (293 ppm) or n-heptane (505 ppm) individually. Sub-Tg annealing reduced carbon dioxide permeance during actual contaminant exposure more severely than in non-annealed fibers. On the other hand, except for exposure to the highest n-heptane contaminant feed (2003 ppm), annealing significantly reduced the post-exposure conditioning observed in carbon dioxide permeance and carbon dioxide/methane selectivity. It appears that annealing allows the consolidation of segmental packing which stabilized the glassy matrix against swelling. At sufficiently high activities of even a relatively non-interacting penetrant like n-heptane, the annealing-induced stabilization can be reversed. © 2010 Elsevier B.V. All rights reserved.

  18. Antiplasticization and plasticization of Matrimid® asymmetric hollow fiber membranes—Part A. Experimental

    Lee, Jong Suk; Madden, William; Koros, William J.

    2010-01-01

    The complex effects of highly sorbing feed gas contaminants such as toluene and n-heptane on performance of both annealed and non-annealed Matrimid® asymmetric fibers relevant to CO2/CH4 separation are reported. Membrane performance was quantified both during contaminant exposure and after removal of the contaminant from the feed stream. Exposure to either toluene or n-heptane during permeation reduces carbon dioxide permeance and the carbon dioxide/methane selectivity in non-annealed fibers. After exchange with a contaminant-free feed containing only CO2 and CH4 mixed gas, the carbon dioxide permeance and carbon dioxide/methane selectivity were affected, indicating a glassy state conditioning effect due to the prior contaminant exposure. Interestingly, the conditioning effect after simultaneous exposure to toluene and n-heptane (284 ppm toluene and 504 ppm n-heptane) was less than the conditioning observed for either toluene (293 ppm) or n-heptane (505 ppm) individually. Sub-Tg annealing reduced carbon dioxide permeance during actual contaminant exposure more severely than in non-annealed fibers. On the other hand, except for exposure to the highest n-heptane contaminant feed (2003 ppm), annealing significantly reduced the post-exposure conditioning observed in carbon dioxide permeance and carbon dioxide/methane selectivity. It appears that annealing allows the consolidation of segmental packing which stabilized the glassy matrix against swelling. At sufficiently high activities of even a relatively non-interacting penetrant like n-heptane, the annealing-induced stabilization can be reversed. © 2010 Elsevier B.V. All rights reserved.

  19. Thermal and catalytic cracking of ethylene in presence of CaO, MgO, zeolite and calcined dolomite

    Taralas, G; Sjoestroem, K; Jaeraas, S; Bjoernbom, E [Royal Inst. of Tech., Stockholm (Sweden). Dept. of Chemical Technology

    1994-12-31

    The subject of the present work is to study the effect of catalysts such as calcined dolomite (CaO.MgO), CaO (quicklime), MgO and Zeolite (EKZ-4) on the cracking of ethylene in the presence and absence of steam. N-heptane, toluene, naphthalene, thiophene have been some suitable model compounds for studies of the thermal and catalytic decomposition of tar. Previous results showed that the reaction scheme of the thermal decomposition of n-heptane was consistent with the high yield of ethylene observed in thermal decomposition of n-heptane. The effect of the reactor wall and the ferric impurities in the dolomite are also subjects of the research in this study. The results may also throw some additional light on the nature of the gas-phase thermal and catalytic reactions occurring in the use of dolomite as tar cracking catalysts. 28 refs

  20. Measurement and correlation of critical properties for binary mixtures and ternary mixtures containing gasoline additives

    Wang, Lipu; Han, Kewei; Xia, Shuqian; Ma, Peisheng; Yan, Fangyou

    2014-01-01

    Highlights: • A high-pressure view cell was used to measure the critical properties of mixtures. • Three binary mixtures’ and three ternary mixtures’ critical properties were reported. • The experimental data of each system covered the whole mole fraction range. • The critical properties of the ternary mixtures were predicted with the PR–WS model. • Empirical equations were used to correlate the experimental results. - Abstract: The critical properties of three binary mixtures and three ternary mixtures containing gasoline additives (including methanol + 1-propanol, heptane + ethanol, heptane + 1-propanol, methanol + 1-propanol + heptane, methanol + 1-propanol + methyl tert-butyl ether (MTBE), and ethanol + heptane + MTBE) were determined by a high-pressure cell. All the critical lines of binary mixtures belong to the type I described by Scott and van Konynenburg. The system of methanol + 1-propanol showed little non-ideal behavior due to their similar molecular structures. The heptane + ethanol and heptane + 1-propanol systems showed visible non-ideal behavior for their great differences in molecular structure. The Peng–Robinson equation of state combined with the Wong–Sandler mixing rule (PR–WS) was applied to correlate the critical properties of binary mixtures. The critical points of the three ternary mixtures were predicted by the PR–WS model with the binary interaction parameters using the procedure proposed by Heidemann and Khalil. The predicted critical temperatures were in good agreement with the experimental values, while the predicted critical pressures differed from the measured values. The experimental values of binary mixtures were fitted well with the Redlich–Kister equation. The critical properties of ternary mixtures were correlated with the Cibulka’s equation, and the critical surfaces were plotted using the Cibulka’s equations

  1. Compositional effects on PAH and soot formation in counterflow diffusion flames of gasoline surrogate fuels

    Park, Sungwoo

    2017-02-05

    Gasoline surrogate fuels are widely used to understand the fundamental combustion properties of complex refinery gasoline fuels. In this study, the compositional effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation were investigated experimentally for gasoline surrogate mixtures comprising n-heptane, iso-octane, and toluene in counterflow diffusion flames. A comprehensive kinetic model for the gasoline surrogate mixtures was developed to accurately predict the fuel oxidation along with the formation of PAHs and soot in flames. This combined model was first tested against ignition delay times and laminar burning velocities data. The proposed model for the formation and growth of PAHs up to coronene (C24H12) was based on previous studies and was tested against existing and present new experimental data. Additionally, in the accompanied soot model, PAHs with sizes larger than (including) pyrene were used for the inception of soot particles, followed by particle coagulations and PAH condensation/chemical reactions on soot surfaces. The major pathways for the formation of PAHs were also identified for the surrogate mixtures. The model accurately captures the synergistic PAH formation characteristics observed experimentally for n-heptane/toluene and iso-octane/toluene binary mixtures. Furthermore, the present experimental and modeling results also elucidated different trends in the formation of larger PAHs and soot between binary n-heptane/iso-octane and ternary n-heptane/iso-octane/toluene mixtures. Propargyl radicals (C3H3) were shown to be important in the formation and growth of PAHs for n-heptane/iso-octane mixtures when the iso-octane concentration increased; however, reactions involving benzyl radicals (C6H5CH2) played a significant role in the formation of PAHs for n-heptane/iso-octane/toluene mixtures. These results indicated that the formation of PAHs and subsequently soot was strongly affected by the composition of gasoline surrogate mixtures.

  2. Kinetics of acyl transfer reactions in organic media catalysed by Candida antarctica lipase B.

    Martinelle, M; Hult, K

    1995-09-06

    The acyl transfer reactions catalysed by Candida antartica lipase B in organic media followed a bi-bi ping-pong mechanism, with competitive substrate inhibition by the alcohols used as acyl acceptors. The effect of organic solvents on Vm and Km was investigated. The Vm values in acetonitrile was 40-50% of those in heptane. High Km values in acetonitrile compared to those in heptane could partly be explained by an increased solvation of the substrates in acetonitrile. Substrate solvation caused a 10-fold change in substrate specificity, defined as (Vm/Km)ethyl octanoate/(Vm/Km)octanoic acid, going from heptane to acetonitrile. Deacylation was the rate determining step for the acyl transfer in heptane with vinyl- and ethyl octanoate as acyl donors and (R)-2-octanol as acyl acceptor. With 1-octanol, a rate determining deacylation step in heptane was indicated using the same acyl donors. Using 1-octanol as acceptor in heptane, S-ethyl thiooctanoate had a 25- to 30-fold lower Vm/Km value and vinyl octanoate a 4-fold higher Vm/Km value than that for ethyl octanoate. The difference showed to be a Km effect for vinyl octanoate and mainly a Km effect for S-ethyl thiooctanoate. The Vm values of the esterification of octanoic acid with different alcohols was 10-30-times lower than those for the corresponding transesterification of ethyl octanoate. The low activity could be explained by a low pH around the enzyme caused by the acid or a withdrawing of active enzyme by nonproductive binding by the acid.

  3. Compositional effects on PAH and soot formation in counterflow diffusion flames of gasoline surrogate fuels

    Park, Sungwoo; Wang, Yu; Chung, Suk-Ho; Sarathy, Mani

    2017-01-01

    Gasoline surrogate fuels are widely used to understand the fundamental combustion properties of complex refinery gasoline fuels. In this study, the compositional effects on polycyclic aromatic hydrocarbons (PAHs) and soot formation were investigated experimentally for gasoline surrogate mixtures comprising n-heptane, iso-octane, and toluene in counterflow diffusion flames. A comprehensive kinetic model for the gasoline surrogate mixtures was developed to accurately predict the fuel oxidation along with the formation of PAHs and soot in flames. This combined model was first tested against ignition delay times and laminar burning velocities data. The proposed model for the formation and growth of PAHs up to coronene (C24H12) was based on previous studies and was tested against existing and present new experimental data. Additionally, in the accompanied soot model, PAHs with sizes larger than (including) pyrene were used for the inception of soot particles, followed by particle coagulations and PAH condensation/chemical reactions on soot surfaces. The major pathways for the formation of PAHs were also identified for the surrogate mixtures. The model accurately captures the synergistic PAH formation characteristics observed experimentally for n-heptane/toluene and iso-octane/toluene binary mixtures. Furthermore, the present experimental and modeling results also elucidated different trends in the formation of larger PAHs and soot between binary n-heptane/iso-octane and ternary n-heptane/iso-octane/toluene mixtures. Propargyl radicals (C3H3) were shown to be important in the formation and growth of PAHs for n-heptane/iso-octane mixtures when the iso-octane concentration increased; however, reactions involving benzyl radicals (C6H5CH2) played a significant role in the formation of PAHs for n-heptane/iso-octane/toluene mixtures. These results indicated that the formation of PAHs and subsequently soot was strongly affected by the composition of gasoline surrogate mixtures.

  4. Effect of Molecular Size of Solutes on Their Partial Molar Volumes in Supercritical n-Pentane

    2001-01-01

    The densities of n-pentane, methane-n-pentane, propane-n-pentane, n-heptane-n-pentane, and n-decane-n-pentane binary mixtures were determined at 476.5K in the pressure range from 2 to 5 MPa. The partial molar volumes of the solutes in n-pentane were calculated using the density data. It was found that the partial molar volumes of methane and propane are positive , while those of n-heptane and n-decane are negative.

  5. Reduction of reversed micelle entrapped cytochrome c and cytochrome c3 by electrons generated by pulse radiolysis or by pyrene photoionization

    Vlsser, A.J.W.G.; Fendler, J.H.

    1982-01-01

    Horse heart cytochrome c and cytochrome c 3 , isolated from Desulfovibrio vulgaris, have been incorporated in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) entrapped water pools in heptane. The absorption spectra of the cytochromes have been found to be strongly dependent on the water to AOT concentration ratios. The proteins solubilized in heptane by the AOT reversed micelles have retained their ability to mediate electron transfer. They reacted very rapidly with hydrated electrons, generated pulse radiolytically or, alternatively, formed in the laser photoionization of pyrene

  6. Investigation of W/O microemulsion droplets by contrast variation ...

    various molar ratios (µ) of water to AOT and temperatures on water-in-oil (W/O) mi- croemulsions dispersed in n-heptane, ... tures composed of surfactant, water, and oil have attracted much interest since they form thermodynamically stable phases .... filter into dust-free sample cells. The cylindrical sample cells are made of ...

  7. Alkanes and terpenes in wood and leaves of Pinus jeffreyi and P. sabiniana

    Robert P. Adams; Jessica W. Wright

    2012-01-01

    The wood oils of Pinus jeffreyi and P. sabiniana contain considerable amounts of heptane (76.6%, 92%), on a monoterpene basis. However, when entire wood extractables is considered, the amounts drop considerably (3.4%, 36.8%) with the major portion of the wood oils being diterpene acids. The leaf oil of P. jeffreyi...

  8. Reduced chemical kinetic mechanisms for hydrocarbon fuels

    Montgomery, C.J.; Cremer, M.A.; Heap, M.P.; Chen, J-Y.; Westbrook, C.K.; Maurice, L.Q.

    1999-01-01

    Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, a variety of different reduced chemical kinetic mechanisms for ethylene and n-heptane have been generated. The reduced mechanisms have been compared to detailed chemistry calculations in simple homogeneous reactors and experiments. Reduced mechanisms for combustion of ethylene having as few as 10 species were found to give reasonable agreement with detailed chemistry over a range of stoichiometries and showed significant improvement over currently used global mechanisms. The performance of reduced mechanisms derived from a large detailed mechanism for n-heptane was compared to results from a reduced mechanism derived from a smaller semi-empirical mechanism. The semi-empirical mechanism was advantageous as a starting point for reduction for ignition delay, but not for PSR calculations. Reduced mechanisms with as few as 12 species gave excellent results for n-heptane/air PSR calculations but 16-25 or more species are needed to simulate n-heptane ignition delay

  9. Application of association models to mixtures containing alkanolamines

    Avlund, Ane Søgaard; Eriksen, Daniel Kunisch; Kontogeorgis, Georgios

    2011-01-01

    Two association models,the CPA and sPC-SAFT equations of state, are applied to binarymixtures containing alkanolamines and hydrocarbons or water. CPA is applied to mixtures of MEA and DEA, while sPC-SAFT is applied to MEA–n-heptane liquid–liquid equilibria and MEA–water vapor–liquid equilibria. T...

  10. A NIST Kinetic Data Base for PAH Reaction and Soot Particle Inception During Combusion

    2007-12-01

    official policy or position of the Department of Defense. Reference herein to any specific commercial product, process, or service by trade name...becomes richer. We have thus intergrated 51 unimolecular decomposition and 5 isomerization reactions and 24 species processes into a heptane

  11. Organo-gel de heptano: diagrama de fases e aplicações sintéticas

    Queiroz Neide

    1999-01-01

    Full Text Available The phase diagram formation of microemulsion-based gels composed of an anionic surfactant aerosol-OT sodium bis (2-ethylhexyl-sulphosuccinate, water, gelatin and an organic solvent is presented for heptane. The stability of this organo- gel, when an enzyme is immobilized is discussed in terms of its reutilization in various esters synthesis.

  12. Mapping surrogate gasoline compositions into RON/MON space

    Morgan, N.; Smallbone, A.; Bhave, A.; Kraft, M.; Cracknell, R.; Kalghatgi, G.T.

    2010-01-01

    In this paper, new experimentally determined octane numbers (RON and MON) of blends of a tri-component surrogate consisting of toluene, n-heptane, i-octane (called toluene reference fuel TRF) arranged in an augmented simplex design are used to derive a simple response surface model for the octane

  13. Modeling vapor-liquid interfaces with the gradient theory in combination with the CPA equation of state

    Queimada, Antonio; Miqueu, C; Marrucho, IM

    2005-01-01

    and the correct phase equilibrium of water + hydrocarbon systems already obtained from CPA. In this work, preliminary studies involving the vapor-liquid interfacial tensions of some selected associating and non-associating pure components (water, ethanol, n-butane, n-pentane, n-hexane, n-heptane) are presented...

  14. Steam cracking of hydrocarbons 6. Effect of dibenzyl sulfide and dibenzyl disulfide on reaction kinetics and coking

    Bajus, M.; Baxa, J.; Leclercq, P.A.; Rijks, J.A.

    1983-01-01

    The influence of aromatic sulfides on the kinetics and selectivity of hydrocarbon conversion by steam cracking and on pyrolytic coke formation was investigated in stainless steel tubular reactors with relatively large inner surface.The rate of decomposition of heptane (at 700 ‘C, 100 kPa, and a mass

  15. Synthesis of CaCO3 nanoparticles by carbonation of lime solutions in reverse micellar systems

    Heeres, H.J.; Jain, R.; Mehra, A.; Dagaonkar, M.V.

    2004-01-01

    Application of reverse micelles for the synthesis of nano-sized calcium carbonate particles in different solvents (cyclohexane, decane and heptane) has been investigated. The effect of the mole ratio of water-to-surfactant (R) and type of solvent has been studied on the size and nature of the

  16. Determination of ten steroid hormones in animal waste manure and agricultural soil using inverse and integrated clean-up pressurized liquid extraction and gas chromatography-tandem mass spectrometry

    Hansen, Martin; Krogh, Kristine Andersen; Halling-Sørensen, Bent

    2011-01-01

    ... Martin Hansen , Kristine A. Krogh , Bent Halling ... in a 22 mL PLE cell : firstly by flushing the sample with heptane to remove unwanted matrix components (inverse- PLE , i- PLE ) and secondly, performing internal clean-up (ic- PLE ) and eluting the steroid hormones by attaching an ...

  17. MAO-A inhibitory activity of quercetin from Calluna vulgaris (L.) Hull

    Saaby, Lasse; Rasmussen, Hasse Bonde; Jäger, Anna Katharina

    2009-01-01

    AIM OF THE STUDY: This study investigated MAO-A inhibitory activity of methanol extract of Calluna vulgaris (L.) Hull., which traditionally has been used as a nerve calming remedy. MATERIALS AND METHODS: A methanolic extract of Calluna vulgaris was partitioned against heptane, ethyl acetate...

  18. Journal of Chemical Sciences | Indian Academy of Sciences

    The ground-state triple proton/H-atom transfer (GSTPT/GSTHAT) reactions in HCOOH complexed cyclically with H₂O, CH₃OH, NH₃ and mixed solvents H₂O-NH₃/CH₃ OH-NH₃ were studied byquantum mechanical methods in heptane. The GSTPT/GSTHAT in HCOOH-(H₂O) ₂, HCOOH-(CH₃OH)₂, ...

  19. Quaternary (liquid + liquid) equilibrium data for the extraction of toluene from alkanes using the ionic liquid [EMim][MSO4

    Corderí, Sandra; Calvar, Noelia; Gómez, Elena; Domínguez, Ángeles

    2014-01-01

    Highlights: • EMim[MSO 4 ] was proposed as solvent for the extraction of toluene from alkanes. • The quaternary system {heptane + cyclohexane + toluene + [EMim][MSO 4 ]} was evaluated. • The extraction of toluene would be facilitated in the presence of one alkane. • Experimental LLE data were successfully correlated with the NRTL model. - Abstract: (Liquid + liquid) equilibrium (LLE) studies for the extraction of aromatics from alkanes present in the petroleum fractions are important to develop theoretical/semiempirical (liquid + liquid) equilibrium models, which are used in the design of extraction processes. In this work, the ionic liquid 1-ethyl-3-methylimidazolium methylsulfate, [EMim][MSO 4 ], was evaluated as potential solvent for the separation of toluene from heptane and cyclohexane. The LLE data for the quaternary system {heptane (1) + cyclohexane (2) + toluene (3) + [EMim][MSO 4 ] (4)} were experimentally determined at T = 298.15 K and atmospheric pressure. Moreover, the LLE data for the ternary systems {heptane or cyclohexane (1) + toluene (2) + [EMim][MSO 4 ] (3)} were also determined. Solute distribution ratios and selectivities were calculated and analysed in order to evaluate the capability of the ionic liquid to accomplish the separation target. A comparison between the solute distribution ratios and selectivities for the quaternary and the ternary systems was also made. Finally, the experimental tie-line data were correlated with the NRTL model

  20. Pramana – Journal of Physics | Indian Academy of Sciences

    The dielectric relaxation phenomena of rigid polar liquid molecules chloral and ethyltrichloroacetate () in benzene, -hexane and -heptane () under 4.2, 9.8 and 24.6 GHz electric fields at 30°C are studied to show the possible existence of double relaxation times 2 and 1 for rotations of the whole and the flexible ...

  1. Experimental phase behavior study of a five-component model gas condensate

    Shariati - Sarabi, A.; Straver, E.J.M.; Florusse, L.J.; Peters, C.J.

    2014-01-01

    In this work, the bubble points and dew points of a multicomponent mixture of methane, butane, heptane, decane and tetradecane as a model mixture representative of a gas condensate, have been measured experimentally. Ten samples with approximately the same composition were prepared and their

  2. Few studies of the effect of diluents on extraction of cobalt with D2EHPA. D2EHPA ni yoru Co no chushutsu ni ataeru kishakuzai no eikyo ni kansuru jakkan no kento

    Aranae, M.; Nakataka, Y.; Wakamatsu, T. (Kyoto Univ., Kyoto (Japan). Faculty of Engineering); Saito, I.; Sakamoto, H. (Environment Research Inst. Resources Technical Tsukuba (Japan))

    1991-12-27

    Study was made on extraction of cobalt from weak acid solution with di-(2-ethylhexyl) phosphoric acid (D2EHPA) using various polar diluents such as benzene, toluene, o-xylene, m-xylene, n-heptane, cyclohexane and n-hepatne-benzene mixtures. Extraction efficiency of cobalt has decreased in the order, n-heptane > cyclohexane > m-xylene > o-xylene > toluene > benzene and this order has been in good agreement with the decreasing order of solubility parameters of diluents,and has shown the possibility of application of regular solution theory. When n-heptane and cyclohexane as diluents, in low loading ratio(L),were used Co-D2EHPA polymer were formed compared to other diluents. On the other hand when mixture of n-heptane/benzene was used as diluent, the efficiency of extraction, salting-out effect and formation of Co-D2EHPA polymer has changed with the texture of mixture.This change may be due to the effect of L and it has been thought for the necessity of investigation of extraction of cobalt in low polar diluents. 13 refs., 5 figs., 2 tabs.

  3. Structure of fenchone by broadband rotational spectroscopy

    Loru, Donatella; Bermúdez, Miguel A.; Sanz, M. Eugenia [Department of Chemistry, King’s College London, London SE1 1DB (United Kingdom)

    2016-08-21

    The bicyclic terpenoid fenchone (C{sub 10}H{sub 16}O, 1,3,3-trimethylbicyclo[2.2.1]heptan-2-one) has been investigated by chirped pulse Fourier transform microwave spectroscopy in the 2-8 GHz frequency region. The parent species and all heavy atom isotopologues have been observed in their natural abundance. The experimental rotational constants of all isotopic species observed have been determined and used to obtain the substitution (r{sub s}) and effective (r{sub 0}) structures of fenchone. Calculations at the B3LYP, M06-2X, and MP2 levels of theory with different basis sets were carried out to check their performance against experimental results. The structure of fenchone has been compared with those of norbornane (bicyclo[2.2.1]heptane) and the norbornane derivatives camphor (1,7,7-trimethylbicyclo[2.2.1]heptan-2-one) and camphene (3,3-dimethyl-2-methylenebicyclo[2.2.1]heptane), both with substituents at C{sub 2}. The structure of fenchone is remarkably similar to those of camphor and camphene. Comparison with camphor allows identification of changes in ∠CCC angles due to the different position of the methyl groups. All norbornane derivatives display similar structural changes with respect to norbornane. These changes mainly affect the bond lengths and angles of the six-membered rings, indicating that the substituent at C{sub 2} drives structural adjustments to minimise ring strain after its introduction.

  4. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    Alfazazi, Adamu; Kuti, Olawole Abiola; Naser, Nimal; Chung, Suk-Ho; Sarathy, Mani

    2016-01-01

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate

  5. Hydrogen Bonding Interaction between 1-Propanol and Acrylic ...

    The association between 1-propanol and acrylic esters (methyl methacrylate, ethyl methacrylate and butyl methacrylate) in non-polar solvents, viz. n-heptane, CCl4, and benzene has been investigated by means of FTIR spectroscopy. The formation constants of the 1:1 complexes have been calculated using Nash's method.

  6. Impurity distribution behavior in caprolactam extraction with environmentally benign mixed solvents

    Delden, van M.L.; Drumm, C.; Kuipers, N.J.M.; Haan, de A.B.

    2006-01-01

    In a previous study a solvent mixture of heptane containing 40 mass % heptanol was selected as an alternative in the industrial extraction of caprolactam to replace benzene, toluene, or chlorinated hydrocarbons. This work reports the equilibrium distribution ratio of caprolactam and four model

  7. Proceedings of the Twelfth Conference on Environmental Toxicology 3, 4 and 5 November 1981

    1982-04-01

    aTentative assignments are Compound A = n-heptane, B=methylcyclohexane, C=2,5-.dimethylhexane, D=toluene, E= XTHDCPD isomer of dicyclopentadiene. b...2.5-dimethyl- hexane, C = toluene, D = XTHDCPD isomer of dicyclopentadiene. TABLE 6. PHOTOLYSIS OF JP-4 IN WATER Fuel Component Concentration (mg

  8. The influence of carbon and oxygen on the magnetic characteristics of press-less sintered NdFeB magnets

    Xia, Manlong; Abrahamsen, Asger Bech; Bahl, Christian

    2017-01-01

    The Pressless Process (PLP) was adopted to manufacture NdFeB sintered magnets, where the investigations on carbon and oxygen residues from heptane milling liquid media and graphite crucibles used for sintering were quantified to evaluate the influence on the magnetic characteristics. The carbon...

  9. Fuel effects on illumination ignition delay and soot lift-off length in diesel combustion

    Frijters, P.J.M.; Vallen, R.G.M.; Somers, L.M.T.; Luijten, C.C.M.; Baert, R.S.G.; Skevis, G.

    2007-01-01

    Ignition behavior of different fuels is investigated by recording broadband soot luminosity at high speed (60 kHz).The tested fuels are regular low sulphur EN 590:2004 fuel, EN 14214:2003 (FAME), n-heptane and IDEA (2component surrogate fuel), all with a Cetane Index between 51 and 57. For this an

  10. Analysis of poly(styrene-co-methyl acrylate) and poly(styrene-co-butyl acrylate) by high-performance liquid chromatography

    Sparidans, R.W.; Claessens, H.A.; van Doremaele, G.H.J.; Herk, van A.M.

    1990-01-01

    Poly(styrene—co-methyl acrylate) and poly(styrene—co-butyl acrylate) were separated according to their chemical composition by gradient elution. The chromatographic separation on silica was optimized for a gradient ranging from n-heptane as a non-solvent to dichloromethane containing a small amount

  11. Elastic Modulus at High Frequency of Polymerically Stabilized Suspensions

    Nommensen, P.A.; Duits, Michael H.G.; van den Ende, Henricus T.M.; Mellema, J.

    2000-01-01

    The elastic moduli of polymerically stabilized suspensions consisting of colloidal silica particles coated with endgrafted PDMS (Mn = 80 000) in heptane, were measured as a function of concentration. And the elastic modulus at high frequency G'.. was quantitatively described by model calculations

  12. synthesis, characterization and thermal degradation of oligo

    Preferred Customer

    NaOCl and 2200, 2500 g mol-1 and 1.136 for oxidation by air. With the optimum ... electrochemical properties. Because of these ... 4-Iodoaniline (4-IA), salicylaldehyde (SA), methanol (MeOH), ethanol, benzene, acetone, toluene, heptane ...

  13. A DFT exploration of the enantioselective rearrangement of cyclohexene oxide to cyclohexenol

    Brandt, Peter; Norrby, Per-Ola; Andersson, Pher G.

    2003-01-01

    In this paper, we present computational results for the (1S,3R,4R)-3-(pyrrolidinyl)-methyl-2-azabicyclo[2.2.1]heptane mediated rearrangement of cyclohexene oxide. The results nicely explain the differences in enantioselectivities between catalytic and stoichiometric mode between different ligands...

  14. Numerical Simulation of Condensation of Sulfuric Acid and Water in a Large Two-stroke Marine Diesel Engine

    Walther, Jens Honore; Karvounis, Nikolas; Pang, Kar Mun

    2016-01-01

    We present results from computational fluid dynamics simulations of the condensation of sulfuric acid (H2SO4) and water (H2O) in a large two-stroke marine diesel engine. The model uses a reduced n-heptane skeletal chemical mechanism coupled with a sulfur subsetto simulate the combustion process...

  15. Laser Diagnostics for Reacting Flows

    2010-01-11

    the high-temperature kinetics of n-heptane pyrolysis . The two-wavelength temperature and vapor concentration diagnostic designed for n- dodecane was...features ranging from 1338 nm to 1469 nm and one laser tuned to a CO2 transition near 1997 nm were combined onto a single mode optical fiber ( Corning

  16. Ascorbyl radical disproportionation in reverse micellar systems

    Gębicki, J. L.; Szymańska-Owczarek, M.; Pacholczyk-Sienicka, B.; Jankowski, S.

    2018-04-01

    Ascorbyl radical was generated by the pulse radiolysis method and observed with the fast kinetic spectrophotometry within reverse micelles stabilized by AOT in n-heptane or by Igepal CO-520 in cyclohexane at different water to surfactant molar ratio, w0. Rate constants for the disproportionation of the ascorbyl radicals were smaller than those for intermicellar exchange for both type of reverse micelles and slower than those in homogeneous aqueous solutions. However, they increased with increasing w0 for AOT/n-heptane system, while they decreased for Igepal CO-520 system. The absorption spectra of ascorbic acid AOT/n-heptane reverse micellar system showed that the "pH" sensed by this molecule is lower than that in respective homogeneous aqueous solutions. The obtained results were rationalized taking into account three main factors (i) preferential location of ascorbic acid molecules in the interfacial region of the both types of reverse micelles; (ii) postulate that the pH of the interface is lower than that of the water pool of reverse micelles and (iii) different structure of the interface of the reverse micelles made by AOT in n-heptane and those formed by Igepal CO-520 I cyclohexane. Some possible consequences of these findings are discussed.

  17. CATALYTIC PROPERTIES AND ACIDITY OF MODIFIED MCM-41 ...

    Adsorption of pyridine and IR spectroscopy indicated various types of Lewis and Brönsted acid sites. The density distribution of acid sites was determined by TPD. Both Lewis and Brönsted acid sites were found to be active in the heptane isomerisation. The presence of aluminium (low Si/Al) combined to the ionic exchange ...

  18. 78 FR 50147 - 2012 Liquid Chemical Categorization Updates

    2013-08-16

    ... Amylene, see Pentene (all isomers) Animal acid oil Animal and Fish acid oils and distillates, n.o.s...) ether Dithiocarbamate ester (C7-C35) X Distillates: Flashed feed stocks I Straight run I Diundecyl... oil Groundnut oil Y Hazelnut oil Heartcut distillate I Heptadecane, see n-Alkanes (C10+) Heptane (all...

  19. Investigation of Asphaltene Precipitation at Elevated Temperature

    Andersen, Simon Ivar; Lindeloff, Niels; Stenby, Erling Halfdan

    1998-01-01

    In order to obtain quantitative data on the asphaltene precipitation induced by the addition of n-alkane (heptane) at temperatures above the normal boiling point of the precipitant, a high temperature/high pressure filtration apparatus has been constructed. Oil and alkane are mixed...

  20. De invloed van de samenstelling van binaire mengsels op het schotelrendement in rectificatiekolommen

    Thijssen, H.A.C.

    1955-01-01

    The effect of composition on plate efficiencies for binary mixtures of ethanol and water, n-heptane and methylcyclohexane, and methylcyclohexane and toluene was studied experimentally in an adiabatic distillation column of 3.8 cm internal diameter containing 9 sieve plates. Accurate data concerning

  1. β-Carotene as a factor in the reconstitution of cyclic phospho rylation in damaged chloroplast membranes

    Anna Tukendorf

    2014-01-01

    Full Text Available Phenazine methosulphate mediated cyclic phosphorylation suppressed by heptane extraction or galactolipase treatment of spinach chloroplasts is restored by β -carotene, in 100% and 50%, respectively. Xanthophylls are not able to reconstitute this reaction. β-Carotene replaces galactolipids in reactivation of galactolipase treated chloroplasts, indicating a nonspecific effect of lipids in photosystem I dependent reactions.

  2. Separation of trace amounts of thorium from cerous nitrate solutions by solvent extraction with tributylphosphate

    Sozanski, A.

    1977-01-01

    Cerous nitrate containing 3 ) 3 in 40% TBP in n-heptane, the extract was scrubed with 8 n HNO 3 . The process is described by a mathematical model which enables control of product purity under various compositions of aqueous feed. (author)

  3. The effects of water addition on pollutant formation from lpp gas turbine combustors

    de Jager, B.; Kok, Jacobus B.W.; Skevis, G.; Dagaut, P.; Sick, V.

    2006-01-01

    Lean premixed prevapourised (LPP) combustion of liquid fuels with steam dilution and under high pressure conditions is numerically assessed. A detailed chemical kinetic mechanism for n-heptane and iso-octane combustion is assembled on the basis of existing detailed mechanisms and validated against

  4. Determination of isobaric thermal expansivity of organic compounds from 0.1 to 30 MPa at 30 degrees C with an isothermal pressure scanning microcalorimeter

    Verdier, Sylvain Charles Roland; Andersen, Simon Ivar

    2003-01-01

    This paper describes a simple high-pressure mercury-free microcalorimetric technique that enables the compression of a fluid from 0.1 to 30 MPa. Thermal expansivities of several compounds were calculated (n-hexane, cyclohexane, heptane, and toluene) with the pressure. scanning transitiometry method...

  5. An optimized chemical kinetic mechanism for HCCI combustion of PRFs using multi-zone model and genetic algorithm

    Neshat, Elaheh; Saray, Rahim Khoshbakhti

    2015-01-01

    Highlights: • A new chemical kinetic mechanism for PRFs HCCI combustion is developed. • New mechanism optimization is performed using genetic algorithm and multi-zone model. • Engine-related combustion and performance parameters are predicted accurately. • Engine unburned HC and CO emissions are predicted by the model properly. - Abstract: Development of comprehensive chemical kinetic mechanisms is required for HCCI combustion and emissions prediction to be used in engine development. The main purpose of this study is development of a new chemical kinetic mechanism for primary reference fuels (PRFs) HCCI combustion, which can be applied to combustion models to predict in-cylinder pressure and exhaust CO and UHC emissions, accurately. Hence, a multi-zone model is developed for HCCI engine simulation. Two semi-detailed chemical kinetic mechanisms those are suitable for premixed combustion are used for n-heptane and iso-octane HCCI combustion simulation. The iso-octane mechanism contains 84 species and 484 reactions and the n-heptane mechanism contains 57 species and 296 reactions. A simple interaction between iso-octane and n-heptane is considered in new mechanism. The multi-zone model is validated using experimental data for pure n-heptane and iso-octane. A new mechanism is prepared by combination of these two mechanisms for n-heptane and iso-octane blended fuel, which includes 101 species and 594 reactions. New mechanism optimization is performed using genetic algorithm and multi-zone model. Mechanism contains low temperature heat release region, which decreases with increasing octane number. The results showed that the optimized chemical kinetic mechanism is capable of predicting engine-related combustion and performance parameters. Also after implementing the optimized mechanism, engine unburned HC and CO emissions predicted by the model are in good agreement with the corresponding experimental data

  6. Combined impact of branching and unsaturation on the autoignition of binary blends in a motored engine

    Kang, Dongil

    2014-11-20

    The impact of a branched and unsaturated compound (diisobutylene) mixed with simple hydrocarbons such as n-heptane and isooctane in binary blends on the autoignition behavior were investigated in a modified cooperative fuel research (CFR) engine at an equivlanece ratio of 0.5 and intake temperature of 120 °C. From this test condition, a homogeneous charge of fuel and intake air can be achieved. The test fuels were prepared by addition of 5-20 vol % diisobutylene into n-heptane and isooctane. The engine compression ratio (CR) was gradually increased from the lowest point to the point where significant high temperature heat release (HTHR) was observed, and this point is also referred to as the critical compression ratio (CCR). Heat release analysis showed that each n-heptane blend had a noticeable low temperature heat release (LTHR), which was not observed in the isooctane blends. The gradual addition of diisobutylene into each primary reference fuel contributed to retarded high temperature heat release in these binary blends, increasing the in-cylinder temperature and decreasing formation of CO. The 15 and 20 vol % blends of diisobutylene in isooctane were not able to reach high temperature heat release in the CFR engine system under these test conditions. The fundamental ignition behavior such as CCR and calculated % LTHR show the impact of the presence of the C-C double bond on ignition reactivity. Species concentration profiles obtained in condensed products from the engine exhaust were measured via gas chromatrography-mass spectrometry and -flame ionization detector. The major intermediate species for each blend were captured at a compression ratio selected just before the high temperature heat release was observed. Most intermediate species were derived from n-heptane and isooctane, while diisobutylene rarely participated in forming any major species, with the exception of the formation of 4,4-dimethyl-2-pentanone. Addition of diisobutylene exhibited opposite

  7. Combined impact of branching and unsaturation on the autoignition of binary blends in a motored engine

    Kang, Dongil; Kirby, Stephen R.; Agudelo, John Ramiro; Lapuerta, Magí n; Al-Qurashi, Khalid; Boehman, André Louis

    2014-01-01

    The impact of a branched and unsaturated compound (diisobutylene) mixed with simple hydrocarbons such as n-heptane and isooctane in binary blends on the autoignition behavior were investigated in a modified cooperative fuel research (CFR) engine at an equivlanece ratio of 0.5 and intake temperature of 120 °C. From this test condition, a homogeneous charge of fuel and intake air can be achieved. The test fuels were prepared by addition of 5-20 vol % diisobutylene into n-heptane and isooctane. The engine compression ratio (CR) was gradually increased from the lowest point to the point where significant high temperature heat release (HTHR) was observed, and this point is also referred to as the critical compression ratio (CCR). Heat release analysis showed that each n-heptane blend had a noticeable low temperature heat release (LTHR), which was not observed in the isooctane blends. The gradual addition of diisobutylene into each primary reference fuel contributed to retarded high temperature heat release in these binary blends, increasing the in-cylinder temperature and decreasing formation of CO. The 15 and 20 vol % blends of diisobutylene in isooctane were not able to reach high temperature heat release in the CFR engine system under these test conditions. The fundamental ignition behavior such as CCR and calculated % LTHR show the impact of the presence of the C-C double bond on ignition reactivity. Species concentration profiles obtained in condensed products from the engine exhaust were measured via gas chromatrography-mass spectrometry and -flame ionization detector. The major intermediate species for each blend were captured at a compression ratio selected just before the high temperature heat release was observed. Most intermediate species were derived from n-heptane and isooctane, while diisobutylene rarely participated in forming any major species, with the exception of the formation of 4,4-dimethyl-2-pentanone. Addition of diisobutylene exhibited opposite

  8. Policosanol extraction from beeswax and improvement of the purity

    Srisaipet Anakhaorn

    2017-01-01

    Full Text Available Policosanol is a mixture of high molecular weight aliphatic long chain alcohols (20-36 carbon atoms. It has been use in pharmaceutical composition and food supplements. This research aimed to isolate and improve the purity of policosanol extracted from beeswax. Triglycerides and other impurities were eliminated from beeswax by refluxing with hexane followed by isopropanol. The purified beeswax was hydrolyzed by refluxing with 1 M ethanolic NaOH for 2 hours. Purification of policosanol was performed by extracting the hydrolyzed product with acetone at 50-60 °C for 3 hours and it was stored at 4 °C for precipitation. The precipitate was refluxed with heptanes followed by washing with hot water. The heptanes layer was kept for policosanol precipitation at 4 °C. The purity of policosanol was confirmed by TLC and high performance liquid chromatography (HPLC. The yield of purified policosanol was 13.23-13.89 %.

  9. Evaluation of the polysubstituted pyridinium ionic liquid [hmmpy][Ntf2] as a suitable solvent for desulfurization: Phase equilibria

    Arce, Alberto; Francisco, Maria; Soto, Ana

    2010-01-01

    Suitability of a pyridinium ionic liquid as a solvent in desulfurization has been analyzed. (Liquid + liquid) equilibria for ternary systems composed by 1-hexyl-3,5-dimethyl pyridinium {bis[trifluoromethylsulfonyl]imide, thiophene, and three hydrocarbons representative of fuel (n-heptane, 2,2,4 trimethylpentane, and toluene) have been determined at T = 298.15 K and atmospheric pressure. High solubility of thiophene in the ionic liquid and also of toluene have been found, being this solvent practically immiscible with 2,2,4 trimethylpentane and heptane. Equilibrium data of these systems have been well correlated with UNIQUAC equations finding the highest deviations for the ternary system involving toluene. NRTL model drove to worse results being considered as not suitable model to correlate the experimental results.

  10. A Convenient Method for Preparation of Pure Standards of Peroxyacetyl Nitrate for Atmospheric Analyses

    Nielsen, Torben; Hansen, A. M.; Lund Thomsen, E.

    1982-01-01

    Peroxyacetyl nitrate (PAN) is synthesized by nitration of peracetic acid (1.2 M), extracted by n- heptane, and purified with normal-phase high-performance liquid chromatography. The purified PAN solution is free of acetyl nitrate. The content of PAN is determined by means of hydrolysis of PAN int...... into nitrite, and determination by ion chromatography of nitrite and nitrate (formed by oxidation of nitrite). The purified PAN solution is used for the calibration of the gas Chromatograph with electron capture detection.......Peroxyacetyl nitrate (PAN) is synthesized by nitration of peracetic acid (1.2 M), extracted by n- heptane, and purified with normal-phase high-performance liquid chromatography. The purified PAN solution is free of acetyl nitrate. The content of PAN is determined by means of hydrolysis of PAN...

  11. The linear rule of metal extraction

    Han Li; Yushuang Wang; Zhichun Chen; Shulan Meng

    1988-01-01

    On the basis of experimental results a linear rule for the solvent extraction of rare earths and yttrium over a definite range of acidity and metal ion concentration is found. Relations between the coefficients of the linear rule and initial acidity are presented for the extraction systems: HEH(EHP)-kerosene-HNO 3 -R(NO 3 ) 3 , HEH(EHP)-kerosene-HCl-RCl 3 , D2EHPA-n-heptane-HCl-RCl 3 , HEH(EHP)-n-heptane-HCl-RCl 3 , where R=La-Nd, Sm-Lu, Y; HEH(EHP)=momo(2-ethyl-hexyl)2-ethyl-hexyl phosphonate; D2EHPA=di(2-ethyl-hexyl) phosphoric acid. 3 refs.; 1 tab

  12. Numerical Simulation of PAHs Formation and Effect of Operating Conditions in DI-Diesel Engines Based on a Comprehensive Chemical Mechanism

    Bei-Jing Zhong

    2013-01-01

    Full Text Available Three-dimensional numerical simulations of polycyclic aromatic hydrocarbon (PAH formation in a Chaochai 6102bzl direct injection diesel engine are performed. n-Heptane is chosen as the fuel. A detailed mechanism, which includes 108 species and 572 elementary reactions that describe n-heptane oxidation and PAH formation, is proposed. A reduced kinetic mechanism, with only 86 reactions and 57 species, is developed and incorporated into computational fluid dynamics (CFD software for the numerical simulations. Results show that PAHs, which were mostly deposited at the bottom of the diesel combustion chamber wall, first increased and then decreased with the increase in diesel crank angle. Furthermore, the diesel engine operating conditions (intake vortex intensity, intake air pressure, fuel injection advance angle, diesel load, and engine speed had a significant effect on PAH formation.

  13. Separation of toluene from alkanes using 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid at T = 298.15 K and atmospheric pressure

    Gonzalez, Emilio J.; Calvar, Noelia; Gonzalez, Begona; Dominguez, Angeles

    2010-01-01

    In this paper, the separation of toluene from aliphatic hydrocarbons (heptane, or octane, or nonane) was analyzed by solvent extraction with 1-ethyl-3-methylpyridinium ethylsulfate ionic liquid, [EMpy][ESO 4 ]. Liquid-liquid equilibrium (LLE) data for the ternary systems {heptane (1) + toluene (2) + [EMpy][ESO 4 ] (3)}, {octane (1) + toluene (2) + [EMpy][ESO 4 ] (3)}, and {nonane (1) + toluene (2) + [EMpy][ESO 4 ] (3)} were obtained by measurements at T = 298.15 K and atmospheric pressure. The selectivity, % removal of aromatic, and solute distribution ratio, obtained from experimental equilibrium results, were used to determine the ability of [EMpy][ESO 4 ] as a solvent. The degree of consistency of the experimental LLE values was ascertained using the Othmer-Tobias and Hand equations. The experimental results for the ternary systems were correlated with the NRTL model. Finally, the results obtained were compared with other ionic liquids and other solvents.

  14. Investigation of atmospheric pressure capillary non-thermal plasmas and their applications to the degradation of volatile organic compounds

    Yin, Shu-Min

    Atmospheric pressure capillary non-thermal plasma (AP-CNTP) has been investigated as a potential technology far the removal of volatile organic compounds (VOCs) in Advanced Life Support Systems (ALS). AP-CNTP is a destructive technology far the removal of VOCs from air streams by active plasma species, such as electrons, ions, and excited molecules. Complete VOC destruction ideally results in the formation of water, carbon dioxide (CO2), and other by-product's may also form, including ozone (O3), nitrous oxide (N2O), nitrogen dioxide (NO2), and decomposed hydrocarbons. Several organic compounds, such as BTEX, ethylene, n-heptane, isooctane, methanol and NH3, were tested in an AP-CNTP system. Parametric experiments were carried out by varying plasma discharge power, flowrates, and initial concentrations. The degradation efficiency varied depending on the chemical nature of the compounds. A plasmochemical kinetic model was derived for toluene, ethylbenzene, and m-xylene and n-heptane.

  15. SEPARATION OF p-AMINOBENZOIC ACID BY REACTIVE EXTRACTION. 1. MECHANISM AND INFLUENCING FACTORS

    DAN CASCAVAL

    2008-09-01

    Full Text Available The comparative study on the reactive extraction of p-aminobenzoic acid with Amberlite LA-2 and D2EHPA in two solvents with different polarity (n-heptane and dichloromethane indicated that the extractant type and solvent polarity control the extraction mechanism. Thus, the reactive extraction with Amberlite LA-2 occurs by means of the interfacial formation of an aminic adduct with three extractant molecules in low-polar solvent, or of an salt with one extractant molecule in higher polar solvent. Similarly, the extraction with D2EHPA is based on the formation of an acidic adduct with two extractant molecules in n-heptane, or of a salt with one extractant molecule in dichloromethane. The most efficient extraction has been reached for the combination Amberlite LA-2-dichloromethane.

  16. Changes in hydrocarbon groups, soil ecotoxicity and microbiology along horizontal and vertical contamination gradients in an old landfarming field for oil refinery waste.

    Mikkonen, Anu; Hakala, Kati P; Lappi, Kaisa; Kondo, Elina; Vaalama, Anu; Suominen, Leena

    2012-03-01

    Horizontal and vertical contaminant gradients in an old landfarming field for oil refinery waste were characterised with the aim to assess parallel changes in hydrocarbon groups and general, microbiological and ecotoxicological soil characteristics. In the surface soil polar compounds were the most prevalent fraction of heptane-extractable hydrocarbons, superseding GC-FID-resolvable and high-molar-mass aliphatics and aromatics, but there was no indication of their relatively higher mobility or toxicity. The size of the polar fraction correlated poorly with soil physical, chemical and microbiological properties, which were better explained by the total heptane-extractable and total petroleum hydrocarbons (TPH). Deleterious effects on soil microbiology in situ were observed at surprisingly low TPH concentrations (0.3%). Due to the accumulation of polar and complexed degradation products, TPH seems an insufficient measure to assess the quality and monitor the remediation of soil with weathered hydrocarbon contamination. Copyright © 2011 Elsevier Ltd. All rights reserved.

  17. Levels of oxylipins, endocannabinoids and related lipids in plasma before and after low-level exposure to acrolein in healthy individuals and individuals with chemical intolerance.

    Claeson, Anna-Sara; Gouveia-Figueira, Sandra; Häggström, Jenny; Fowler, Christopher J; Nording, Malin L

    2017-06-01

    Oxylipins and endocannabinoids play important biological roles, including effects upon inflammation. It is not known whether the circulating levels of these lipids are affected by inhalation of the environmental pollutant acrolein. In the present study, we have investigated the consequences of low-level exposure to acrolein on oxylipin, endocannabinoid and related lipid levels in the plasma of healthy individuals and individuals with chemical intolerance (CI), an affliction with a suggested inflammatory origin. Participants were exposed twice (60min) to heptane and a mixture of heptane and acrolein. Blood samples were collected before exposure, after and 24h post-exposure. There were no overt effects of acrolein exposure on the oxylipin lipidome or endocannibinoids detectable in the bloodstream at the time points investigated. No relationship between basal levels or levels after exposure to acrolein and CI could be identified. This implicates a minor role of inflammatory mediators on the systemic level in CI. Copyright © 2017 Elsevier Ltd. All rights reserved.

  18. The Metabolism of Tetralin in Fischer 344 Rats

    1986-04-01

    would die from the disease . The relevance of nephropathy observed in male rats exposed to various hydrocarbons to the occurrence of renal neoplasia in man...34 often obscure pathologic evaluations. "Old-rat nephropathy" is a common degenerative kidney disease predominantly seen in the male rat. By careful...studies have been performed with n-hexane and n-heptane to characterize their metabolism and role in neurotoxicity (Perbellini et al., 1982; Bahima et

  19. A Study of the Nephrotoxicity and Metabolism of Tetralin and Indan in Fischer 344 Rats.

    1988-02-08

    that 19,700 Americans, approximately two-thirds of them male, would develop renal cancer and 8,900 would die from the disease . The relevance of...pathologic evaluations. "Old-rat nephropathy" is a common degenerative kidney disease predominantly seen in the male rat. By careful examination of tissues...been performed with n-hexane and n-heptane to characterize their metabolism and role in neurotoxicity (Perbellini et al., 1982; Bahima et al., 1984

  20. In-cylinder visualization and engine out emissions from CI to PPC for fuels with different properties

    An, Yanzhao

    2018-02-27

    This study investigated the transition from conventional Compression Ignition (CI) to Partially Premixed Combustion (PPC) in an optical engine for fuels with differing properties. Combustion stratification and emissions were measured with diesel, naphtha and their corresponding surrogate fuels, N-heptane and PRF50. The aim of the study is to link the combustion images with engine out emissions and mixture homogeneity. Single injection strategy with the change of start of injection (SOI) from late to early injections was employed. Results show that combustion phasing trend is similar for diesel/N-heptane as well as for naphtha/PRF50 as the SOI moved from late injection timing to early injection timing. However, there is a significant difference in combustion phasing behavior for gasoline like fuels (naphtha and PRF50) and diesel fuels (diesel and N-heptane). CO emissions show an inverted V-shaped trend with one single peak in the transition zone. A “W” shape trend, with two bottoms at various dilution rates is observed for the UHC emissions. NOX emissions are high in the transition zone and decreased to lower levels in CI and PPC zones. NOX emissions are significantly reduced by reducing the intake O2 concentration with nitrogen. Except for diesel, the other three fuels show lower soot emissions. When compared to diesel like fuels, the natural luminosity of the images are lower for gasoline like fuels, indicating better premixed combustion. As the SOI is changed from CI to PPC mode, the combustion stratification increases towards a peak value in the transition zone and then decreases to a low level in PPC zone. A competition exists between the intake temperature and the dilution rate for the combustion stratification. The level of stratification is higher for real fuels (diesel and naphtha) when compared to surrogate fuel (N-heptane and PRF50).

  1. Hydrogen Bonding Patterns in a Series of 3-Spirocyclic Oxindoles ...

    )-one (1), (rel-1R,2S)-spiro[bicyclo[2.2.1] heptane-2,3'-indol] 2'(1'H)-one (2) and spiro[indole-3,2'-tricyclo[3.3.1.13,7]decan]-2(1H)-one (3) have been determined by low temperature single crystal X-ray diffraction. The effects of substitution on ...

  2. A skeletal mechanism for biodiesel blend surrogates combustion

    An, H.; Yang, W.M.; Maghbouli, A.; Li, J.; Chua, K.J.

    2014-01-01

    Highlights: • A skeletal biodiesel reaction mechanism with 112 species was constructed. • The developed mechanism contains the CO, NO x and soot formation kinetics. • It was well validated against detailed reaction mechanism and experimental results. • The mechanism is suitable to simulate biodiesel, diesel and their blend fuels. - Abstract: A tri-component skeletal reaction mechanism consisting of methyl decanoate, methyl-9-decenoate, and n-heptane was developed for biodiesel combustion in diesel engine. It comprises 112 species participating in 498 reactions with the CO, NO x and soot formation mechanisms embedded. In this study, a detailed tri-component biodiesel mechanism was used as the start of mechanism reduction and the reduced mechanism was combined with a previously developed skeletal reaction mechanism for n-heptane to integrate the soot formation kinetics. A combined mechanism reduction strategy including the directed relation graph with error propagation and sensitivity analysis (DRGEPSA), peak concentration analysis, isomer lumping, unimportant reactions elimination and reaction rate adjustment methods was employed. The reduction process for biodiesel was performed over a range of initial conditions covering the pressures from 1 to 100 atm, equivalence ratios from 0.5 to 2.0 and temperatures from 700 to 1800 K, whereas for n-heptane, ignition delay predictions were compared against 17 shock tube experimental conditions. Extensive validations were performed for the developed skeletal reaction mechanism with 0-D ignition delay testing and 3-D engine simulations. The results indicated that the developed mechanism was able to accurately predict the ignition delay timings of n-heptane and biodiesel, and it could be integrated into 3-D engine simulations to predict the combustion characteristics of biodiesel. As such, the developed 112-species skeletal mechanism can accurately mimic the significant reaction pathways of the detailed reaction

  3. Proceedings of Tripartite Conference on Submarine Medicine and IEP B-52 - France, United Kingdom, United States (6th) Held in Groton, Connecticut on 1-4 June 1987

    1990-10-03

    limits were provided for the following: Chlorcbenzene Cumene (Isopropyl benzene) Cyclohexane Ethyl benzene Heptane Hexane Isopropyl alcohol Methyl...hydrogen removal The removal of carbon monoxyde and hydrogen is done by the catalytic burner whose active product is platinum oxyde deposited on corundum...alumina). The weight of the platinum oxyde represents 1 % of the weight of the catalyst. The CO and H= catalysis is complete at 50’C. For safety, the

  4. Photosensitized production of hydrogen by Halobacterium halobium MMT sub 22 coupled to Escherichia coli in reversed micelles of sodium lauryl sulfate in organic solvents

    Khan, M.M.T.; Bhatt, J.P. (Central Salt and Marine Research Inst., Bhavnagar (India))

    1991-01-01

    Observation on the enhanced production of hydrogen by Halobacterium halobium MMT{sub 22} coupled to Escherichia coli entrapped inside the reversed micelles formed by sodium lauryl sulfate in various organic solvents, namely benzene, carbon tetrachloride, toluene, n-heptane, nitrobenzene, chlorobenzene, are reported. In the present system, a hundred fold increase in activity as compared to the activity in the usual aqueous medium was observed. (author).

  5. Application of [HMim][NTf2], [HMim][TfO] and [BMim][TfO] ionic liquids on the extraction of toluene from alkanes: Effect of the anion and the alkyl chain length of the cation on the LLE

    Corderí, Sandra; González, Emilio J.; Calvar, Noelia; Domínguez, Ángeles

    2012-01-01

    Highlights: ► Several ionic liquids were studied as solvent to extract toluene from heptane and cyclohexane. ► (Liquid + liquid) equilibrium data were measured at 298.15 K and atmospheric pressure. ► Selectivity and solute distribution ratio were calculated and compared with those found in literature for sulfolane. ► Experimental data were correlated using NRTL and UNIQUAC thermodynamic models. - Abstract: In this paper, the separation of toluene from the aliphatic hydrocarbons heptane and cyclohexane employing the ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [HMim][NTf 2 ], 1-hexyl-3-methylimidazolium trifluoromethanesulfonate, [HMim][TfO] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate, [BMim][TfO], as solvents was studied and discussed. Liquid–liquid equilibrium data for the ternary systems {heptane, or cyclohexane + toluene + [HMim][NTf 2 ], or [HMim][TfO], or [BMim][TfO]} and {heptane + cyclohexane + [HMim][NTf 2 ], or [HMim][TfO], or [BMim][TfO]} were measured at T = 298.15 K and atmospheric pressure. The degree of consistency of the tie-lines was tested using the Othmer–Tobias equation. The solute distribution ratio and selectivity, derived from the experimental tie-lines, were used to determine if these ionic liquids can be used as potential solvents on the extraction of toluene from aliphatic hydrocarbons; a comparison with literature data where sulfolane is used as solvent was also included. Finally, the experimental data were correlated with the NRTL and UNIQUAC thermodynamic models.

  6. A molecular dynamics investigation of the unusual concentration dependencies of Fick diffusivities in silica mesopores

    Krishna, R.; van Baten, J.M.

    2011-01-01

    Molecular Dynamics (MD) simulations were carried out to determine the self-diffusivitiy, Di,self, the Maxwell-Stefan diffusivity, Ði, and the Fick diffusivity, Di, for methane (C1), ethane (C2), propane (C3), n-butane (nC4), n-pentane (nC5), n-hexane (nC6), n-heptane (nC7), and cyclohexane (cC6) in

  7. Studies on the liquid-liquid phase distribution equilibria of selenium and its measurement in water using extraction plant with a pulsation column

    Iskanderani, F.; Sobhi, K.M.; Ejaz, M.

    1989-01-01

    Normal heptane, xylene and a 0.01 molar solution of 4-(5-nonyl)pyridine in toluene were investigated as extractants for selenium(IV) from nitric acid media in potassium iodide. Various parameters affecting the distribution of the element are investigated. Extraction at high aqueous to organic phase volume ratio was studied, using a liquid-liquid extraction plant with a pulsation column. The results were employed to measure selenium in spiked water samples. (author) 24 refs.; 8 figs

  8. Studies of Immobilized Homogeneous Metal Catalysts on Silica Supports

    Stanger, Keith James [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    The tethered, chiral, chelating diphosphine rhodium complex, which catalyzes the enantioselective hydrogenation of methyl-α-acetamidocinnamate (MAC), has the illustrated structure as established by 31P NMR and IR studies. Spectral and catalytic investigations also suggest that the mechanism of action of the tethered complex is the same as that of the untethered complex in solution. The rhodium complexes, [Rh(COD)H]4, [Rh(COD)2]+BF4-, [Rh(COD)Cl]2, and RhCl3• 3H2O, adsorbed on SiO2 are optimally activated for toluene hydrogenation by pretreatment with H2 at 200 C. The same complexes on Pd-SiO2 are equally active without pretreatments. The active species in all cases is rhodium metal. The catalysts were characterized by XPS, TEM, DRIFTS, and mercury poisoning experiments. Rhodium on silica catalyzes the hydrogenation of fluorobenzene to produce predominantly fluorocyclohexane in heptane and 1,2-dichloroethane solvents. In heptane/methanol and heptane/water solvents, hydrodefluorination to benzene and subsequent hydrogenation to cyclohexane occurs exclusively. Benzene inhibits the hydrodefluorination of fluorobenzene. In DCE or heptane solvents, fluorocyclohexane reacts with hydrogen fluoride to form cyclohexene. Reaction conditions can be chosen to selectively yield fluorocyclohexane, cyclohexene, benzene, or cyclohexane. The oxorhenium(V) dithiolate catalyst [-S(CH2)3s-]Re(O)(Me)(PPh3) was modified by linking it to a tether that could be attached to a silica support. Spectroscopic investigation and catalytic oxidation reactivity showed the heterogenized catalyst's structure and reactivity to be similar to its homogeneous analog. However, the immobilized catalyst offered additional advantages of recyclability, extended stability, and increased resistance to deactivation.

  9. Study of influence of gas mixture composition on the multistep avalanche chambers characteristics

    Abdushukurov, D.A.; Zanevskij, Yu.V.; Peshekhonov, V.D.

    1987-01-01

    The influence of the concentration of organic quenchers on the operation of multistep avalanche chambers /MSAC/ has been studied. An empirical dependence of the gas amplification factor of MSAC on the quencher concentration has been derived. Measures are considered to increase the stability of the MSAC operation. To improve the MSAC operation argon + n-heptane, neon + methane and neon + argon + methane mixtures are suggested

  10. Fundamental Flame Velocities of Pure Hydrocarbons I : Alkanes, Alkenes, Alkynes Benzene, and Cyclohexane

    Gerstein, Melvin; Levine, Oscar; Wong, Edgar L

    1950-01-01

    The flame velocities of 37 pure hydrocarbons including normal and branched alkanes, alkenes, and alkynes; as well as benzene and cyclohexane, together with the experimental technique employed are presented. The normal alkanes have about the same flame velocity from ethane through heptane with methane being about 16 percent lower. Unsaturation increases the flame velocity in the order of alkanes, alkenes, and alkynes. Branching reduces the flame velocity.

  11. Analysis of metals in asphaltenes of KU-46 by PIXE analysis; Analisis de metales en asfaltenos de crudo mexicano KU-46 por PIXE

    Navidad G, P.; Pina L, L.I.; Lopez M, J.; Ramirez T, J.J.; Aspiazu F, J.A.; Romero G, E.T. [Gerencia de Ciencias Basicas, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)

    2002-07-01

    The content of metals of the asphaltenes obtained from the KU-46 mexican crude with n-heptane was evaluated. The found metals in higher concentration are transition metals as well as the vanadium, nickel, copper and zinc. Moreover the sulfur in high concentrations was quantified. The metallic content of the asphaltenes revealed that the crude contains a lower quantity of metals unlike the vacuum residue previously analysed. (Author)

  12. Plasma Assisted Combustion: Flame Regimes and Kinetic Studies

    2015-01-05

    Schauer, Yiguang Ju, Schlieren Imaging and Pulsed Detonation Engine Testing of Ignition by a Nanosecond Repetitively Pulsed Discharge , submitted to...diffusional cool flames • A heated counterflow burner integrated with vaporization system1 • n-heptane/nitrogen vs. oxygen/ ozone • Ozone generator...micro-DBD) produces 2- 5 % of ozone in oxygen stream, depending on oxygen flow rate • Speciation profiles by using a micro-probe sampling with a

  13. Supercritical Fluid (SCF) Technologies: Assessment of Applicability to Installation Restoration Processes

    1994-03-10

    for the 3 regeneration of activated carbon which had been used for adsorption of pesticides or other I MKO~RT:22SOI.O4~acbva3 -300314𔄃 U * Table 3-3...Dichloroethane Propanol Ethylbenzene Propionic acid I Furfural Trichloroethane Gasoline Trichloroethylene Heptane Toluene Ketones Vinyl acetate Methyl acetate...during extraction from contaminated soil. The polar modifier addition had the further benefit of displacing PAIl molecules at polar adsorption sites on

  14. Analysis of metals in asphaltenes of KU-46 by PIXE analysis

    Navidad G, P.; Pina L, L.I.; Lopez M, J.; Ramirez T, J.J.; Aspiazu F, J.A.; Romero G, E.T.

    2002-01-01

    The content of metals of the asphaltenes obtained from the KU-46 mexican crude with n-heptane was evaluated. The found metals in higher concentration are transition metals as well as the vanadium, nickel, copper and zinc. Moreover the sulfur in high concentrations was quantified. The metallic content of the asphaltenes revealed that the crude contains a lower quantity of metals unlike the vacuum residue previously analysed. (Author)

  15. Effect of food simulating liquids on release of monomers from two dental resin composites

    Ghavam M

    2010-06-01

    Full Text Available "nBackground and Aims: The elution of residual monomers from cured dental composites to oral cavity has a harmful effect on human health and can affect their clinical durability. The purpose of this study was to evaluate the amount of eluted monomers (Bis-GMA, TEGDMA, UDMA from two types of composites (Gradia and P60 after exposure to food simulating liquids such as ethanol (25, 50, 75 % and heptane 50 % for 24 hours and 7 days. "nMaterials and Methods: Forty specimens of each composite were prepared. Equal numbers of each composite were immersed in tubes containing 2cc volumes of 25, 50, 75 % ethanole and 50 % heptane. The amount of eluted monomers in standard condition such as Bis-GMA, TEGDMA and UDMA was measured by GC/MS (Gas Chromatography/Mass Spectroscopy and results were statistically analysed by three way and one way ANOVA. P<0.05 was considered as the level of significancy. "nResults: The results showed that Gradia released more TEGDMA than P60. In assessing the effect of environment, the result showed that ethanol caused releasing monomers more than heptane and the concentration rate of 75 % ethanole resulted in most releasing of monomers. In assessing the effect of time, the observation showed that more monomers were released 7 days compared to 24 hours. Bis-GMA and UDMA were not detected in any solutions in these conditions. "nConclusion: Ethanole caused more release of monomers than heptane and 75 % ethanole released the most amount of monomers. Gradia released more amount of TEGDMA than P60.

  16. Stereocontrolled synthesis of polyhydroxylated bicyclic azetidines as a new class of iminosugars.

    Malinowski, Maciej; Hensienne, Raphaël; Kern, Nicolas; Tardieu, Damien; Bodlenner, Anne; Hazelard, Damien; Compain, Philippe

    2018-06-12

    We report herein the development of a stereodivergent route towards polyhydroxylated bicyclic azetidine scaffolds, namely 6-azabicyclo[3.2.0]heptane derivatives. The strategy hinges on a common bicyclic β-lactam precursor, which is forged by way of a rare example of a cationic Dieckmann-type reaction, followed by IBX-mediated desaturation. Substrate-controlled diastereoselective oxidations then allow the divergent preparation of novel iminosugar mimics.

  17. Laminar Flame Speeds of Gasoline Surrogates Measured with the Flat Flame Method

    Liao, Y.-H.

    2016-01-27

    © 2016 American Chemical Society. The adiabatic, laminar flame speeds of gasoline surrogates at atmospheric pressure over a range of equivalence ratios of = 0.8-1.3 and unburned gas temperatures of 298-400 K are measured with the flat flame method, which produces a one-dimensional flat flame free of stretch. Surrogates used in the current work are the primary reference fuels (PRFs, mixtures of n-heptane and isooctane), the toluene reference fuels (TRFs, mixtures of toluene and PRFs), and the ethanol reference fuels (ERFs, mixtures of ethanol and PRFs). In general, there is good agreement between the present work and the literature data for single-component fuel and PRF mixtures. Surrogates of TRF mixtures are found to exhibit comparable flame speeds to a real gasoline, while there is discrepancy observed between isooctane and gasoline. Moreover, the laminar flame speeds of TRF mixtures with similar fractions of n-heptane are found to be insensitive to the quantity of toluene in the mixture. Mixtures of ERFs exhibit comparable flame speeds to those of TRFs with similar mole fractions of n-heptane and isooctane.

  18. The effect of organic solvent, temperature and mixing time on the production of oil from Moringa oleifera seeds

    Ghazali, Q.; Yasin, N. H. M.

    2016-06-01

    The effect of three different organic solvent, temperature and mixing time on the production of oil from M.oleifera seeds were studied to evaluate the effectiveness in obtaining the high oil yield based on the percentage of oil production. The modified version of Soxhlet extraction method was carried out to extract the oil from M.oleifera seeds by using hexane, heptane and ethanol as the organic solvent. Among the three solvents, it is found that heptane yield higher oil from M.oleifera seeds with maximum oil yield of 36.37% was obtained followed by hexane and ethanol with 33.89% and 18.46%, respectively. By using heptane as a solvent, the temperature (60oC, 70oC, 80oC) and mixing time (6 h, 7 h, and 8 h) were investigated to ensure the high oil yield over the experimental ranges employed and high oil yield was obtained at 600C for 6 h with percentage oil yield of 36.37%. The fatty acid compositions of M.oleifera seeds oil were analyzed using Gas Chromatography/Mass Spectrometry (GC-MS). The main components of fatty acid contained in the oil extracted from M.oleifera seeds was oleic acid, followed by palmitic acid and arachidic acid, and small amount of behenic acid and margaric acid.

  19. Optimization of process parameter and reformer configuration for hydrogen production from steam reforming of heavy hydrocarbons. Paper no. IGEC-1-079

    Chen, Z.; Elnashaie, S.E.H.

    2005-01-01

    The present optimization investigation is classified into reforming configuration optimization in one hand and parameter optimization of each configuration on the other hand. Heptane is used as a model component for heavy hydrocarbons. The proposed novel reforming process is basically a Circulating Fluidized-Bed Membrane Reformer (CFBMR) with continuous catalyst regeneration and gas-solid separation. Composite hydrogen selective membranes are used for removing the product hydrogen from the reacting gas mixture and therefore driving the reversible reactions beyond their thermodynamic equilibriums. Dense perovskite oxygen selective membranes are also used to introduce oxygen for the exothermic oxidation of hydrocarbons and carbon. Four configurations are investigated, two of them are with the catalyst regeneration before the gas-solid separation and the other two are with the catalyst regeneration after the gas-solid separation. The optimization of the performance of each configuration is carried out for a number of design and operating parameters as optimization parameters and under both non-autothermal and autothermal reforming conditions. Results show that the autothermal operation with direct contact between cold feeds (water and heptane) and hot circulating catalyst can be the best configuration for efficient hydrogen production with minimum energy consumption. The maximum net hydrogen yield is 16.732 moles of hydrogen per mole of heptane fed, which is 76.05% of the maximum theoretical hydrogen yield of 22. (author)

  20. Alkylsulfate-based ionic liquids in the liquid–liquid extraction of aromatic hydrocarbons

    García, Silvia; Larriba, Marcos; García, Julián; Torrecilla, José S.; Rodríguez, Francisco

    2012-01-01

    Highlights: ► Values of α 2,1 for the four R-SO 4 ionic liquids are higher than those of sulfolane. ► Values of D 2 for all the ionic liquids are lower than those of sulfolane. ► Values of D 2 for [emim][C 2 H 5 SO 4 ] are the highest among the R-SO 4 ionic liquids. - Abstract: The (liquid + liquid) equilibrium data (LLE) for the extraction of toluene from heptane with different ionic liquids (ILs) based on the alkylsulfate anion (R-SO 4 ) was determined at T = 313.2 K and atmospheric pressure. The effect of more complex R-SO 4 anions on capacity of extraction and selectivity in the liquid–liquid extraction of toluene from heptane was studied. The ternary systems were formed by {heptane + toluene + 1,3-dimethylimidazolium methylsulfate ([mmim][CH 3 SO 4 ]), 1-ethyl-3-methylimidazolium hydrogensulfate ([emim][HSO 4 ]), 1-ethyl-3-methylimidazolium methylsulfate ([emim][CH 3 SO 4 ]), or 1-ethyl-3-methylimidazolium ethylsulfate ([emim][C 2 H 5 SO 4 ])}. The degree of quality of the experimental LLE data was ascertained by applying the Othmer–Tobias correlation. The phase diagrams for the ternary systems were plotted, and the tie lines correlated with the NRTL model compare satisfactorily with the experimental data.

  1. Synthesis and application of magnetic deep eutectic solvents: Novel solvents for ultrasound assisted liquid-liquid microextraction of thiophene.

    Khezeli, Tahere; Daneshfar, Ali

    2017-09-01

    Two novel magnetic deep eutectic solvents (MDESs), comprised of cheap and simple components named [choline chloride/phenol] [FeCl 4 ] and [choline chloride/ethylene glycol] [FeCl 4 ] were prepared and characterized by CHN elemental analysis, proton nuclear magnetic resonance ( 1 H NMR), vibrating sample magnetometery (VSM), Raman, Fourier transform-infrared (FT-IR) and UV-Vis spectrometery. The extraction efficiency of the prepared MDESs has been investigated in ultrasound assisted liquid-liquid microextraction based MDES (UALLME-MDES). Briefly, MDESs were added to n-heptan containing thiophene. Then, MDESs were dispersed in n-heptane by sonication. After that, microdroplets of MDESs were collected by a magnet and the remained concentration of thiophene in n-heptane phase was analyzed by GC-FID. The results indicated that [choline chloride/phenol] [FeCl 4 ] has higher extraction efficiency than [choline chloride/ethylene glycol] [FeCl 4 ]. This work opens a new way to the application of MDESs. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Modification and characterization of sites giving acid cracking on aluminium oxide supports; Modification et caracterisation des sites responsables du craquage acide sur des supports a base d`alumine

    Guillaume, D

    1997-10-23

    The aim of this work is to characterize the surface acid properties of {gamma} alumina, especially the nature, the amount, the strength and the environment of acid sites. The techniques that have been used are: the thermo-desorption of trimethyl-phosphine followed by {sup 31}P MAS NMR, the infrared spectroscopy, the n-heptane cracking, the modification of {gamma} alumina by the addition of chlorine, silicon and alkali (K{sup +}, Na{sup +}), alkaline-earths (Mg{sup 2+}, Ca{sup 2+}), lanthanum (La{sup 3+}) cations. The combination of these techniques has allowed to identify the surface acid properties of {gamma} alumina through the n-heptane transformation reactions under reforming conditions. We have shown that Lewis acidity is responsible for cracking reactions leading to C{sub 1}-C{sub 6} and C{sub 2}-C{sub 5} whereas the cracking of n-heptane producing C{sub 3}-C{sub 4} is due to Broensted acid sites. The isomerization and cyclization reactions both require weaker Broensted acid sites than cracking leading to C{sub 3}-C{sub 4}. The mechanisms involved in the formation of products of these reactions have been identified. Despite the complexity of surface acid properties of {gamma} alumina, this study has determined the environment of catalytically active sites, considering the presence of cation vacancies. (author) 206 refs.

  3. 1,2- and 1,3-dihydroxylated and hydroxynitrogenated monoterpenes as chiral ligands in the asymmetric reformatsky reaction

    Ribeiro, Carlos Magno R.; Morita, Cristina M.; Maia, Monica P.

    2008-01-01

    This study describes the use of three (-)-α-pinene derivatives, one diol-1,2 [(-)- (1R, 2R, 3S, 5R)-2,6,6-trimethylbicyclo[3.1.1]heptane-2,3-diol 4] and two pyridine-hydroxy derivatives [(+)-(1R,2S,3R,5S)-2,6,6- trimethyl-3-(2-pyridinylmethyl)bicyclo[3.1.1]heptane-3-ol 7 and (-)-(1R,2S,3R,5S)-2,6,6-trimethyl-3-[2-(2-pyridinyl) ethyl]bicyclo[3.1.1]heptane-3-ol 8]; one diol-1,3 [(-)-(1S,2R,5S)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 5] derived from (+)-isopulegol 2 and one diol-1,3 [(+)-(1R,2R,5R)-2-(1-hydroxy-1-methylethyl)-5-methylcyclohexanol 6] derived from (+)-neoisopulegol 3, as ligands in the asymmetric Reformatsky reaction. The best enantiomeric excess of β-hydroxy ester obtained in the Reformatsky asymmetric reaction was 18% using ligand 6, and the chemical yield of the reactions was 65% on average. (author)

  4. Relating the octane numbers of fuels to ignition delay times measured in an ignition quality tester (IQT)

    Naser, Nimal

    2016-09-21

    A methodology for estimating the octane index (OI), the research octane number (RON) and the motor octane number (MON) using ignition delay times from a constant volume combustion chamber with liquid fuel injection is proposed by adopting an ignition quality tester. A baseline data of ignition delay times were determined using an ignition quality tester at a charge pressure of 21.3 bar between 770 and 850 K and an equivalence ratio of 0.7 for various primary reference fuels (PRFs, mixtures of isooctane and n-heptane). Our methodology was developed using ignition delay times for toluene reference fuels (mixtures of toluene and n-heptane). A correlation between the OI and the ignition delay time at the initial charge temperature enabled the OI of non-PRFs to be predicted at specified temperatures. The methodology was validated using ignition delay times for toluene primary reference fuels (ternary mixtures of toluene, iso-octane, and n-heptane), fuels for advanced combustion engines (FACE) gasolines, and certification gasolines. Using this methodology, the RON, the MON, and the octane sensitivity were estimated in agreement with values obtained from standard test methods. A correlation between derived cetane number and RON is also provided. (C) 2016 Elsevier Ltd. All rights reserved.

  5. Soot formation characteristics of gasoline surrogate fuels in counterflow diffusion flames

    Choi, Byungchul

    2011-01-01

    The characteristics of polycyclic aromatic hydrocarbon (PAH) and soot for gasoline surrogate fuels have been investigated in counterflow diffusion flames by adopting laser-induced fluorescence (LIF) and laser-induced incandescence (LII) techniques for both soot formation and soot formation/oxidation flames. Tested fuels were three binary mixtures from the primary reference fuels of n-heptane, iso-octane, and toluene. The result showed that PAH and soot maintained near zero level for all mixtures of n-heptane/iso-octane case under present experimental conditions. For n-heptane/toluene and iso-octane/toluene mixtures, PAH initially increased and then decreased with the toluene ratio, exhibiting a synergistic effect. The soot formation increased monotonically with the toluene ratio, however the effect of toluene on soot formation was minimal for relatively small toluene ratios. These results implied that even though toluene had a dominant role in soot and PAH formations, small amount of toluene had a minimal effect on soot formation. Numerical simulations have also been conducted by adopting recently proposed two kinetic mechanisms. The synergistic behavior of aromatic rings was predicted similar to the experimental PAH measurement, however, the degree of the synergistic effect was over-predicted for the soot formation flame, indicating the need for refinements in the kinetic mechanisms. © 2010 Published by Elsevier Inc. on behalf of The Combustion Institute. All rights reserved.

  6. Radiation-thermal purification of waste water from oil pollution

    Mustafaev, I.; Guliyeva, N.; Rzayev, R.; Yagubov, K.

    2004-01-01

    Full text: During the extraction, preparation, transportation and refining of oil the sewages containing oil contaminations are produced. The concentration of oil content in the water depends on used technology and may vary from a thousandths parts up to tens percents. There is a necessity of cleaning this pollution up to a permissible level. There are numerous methods (adsorption, mechanical, chemical and etc) of treating of waster water from oil contaminations. Radiation-chemical method is one of the effective among the above mentioned methods. The results of radiation-thermal decomposition of n-heptane micro-admixtures in water medium are adduced. The main parameters of radiolysis change within the intervals: temperature 20-400 o C, absorbed dose - 0†10.8 kGy at dose rate 3.6 kGy/h. The correlation of n-heptane concentration and water steam changed within [C 5 H 1 2]/[H 2 O] (1-100) 10-5. Total concentration of steam was about 10 20 molec/ml. As a product of decomposition are observed H 2 , CO, CH 4 , C 2 H 4 , C 2 H 6 , C 3 H 8 , C 3 H 6 , C 4 H 8 , hydrocarbons C 5 , and C 6 . The changes of n-heptane concentration in the reactor also were established. The chain regime of n-heptane decomposition at high temperatures in the irradiated mixture is observed. The critical value of temperature and mixture ratio of components, under which the break of chain process of normal n-heptane occurs are defined. The mechanisms of proceeding radiation thermal processes in hydrocarbons-water system are discussed. At the temperatures higher than 300 o C the radiation-thermal decompositions of hydrocarbon micro-impurities in water into gas products occurs according a chain mechanism and the radiation-chemical yield of the decomposition exceeds 100 molec/100eV. This method can be used for purification of sewages from oil contaminations

  7. Recovery of manganese oxides from spent alkaline and zinc–carbon batteries. An application as catalysts for VOCs elimination

    Gallegos, María V., E-mail: plapimu@yahoo.com.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Falco, Lorena R., E-mail: mlfalco@quimica.unlp.edu.ar [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina); Peluso, Miguel A., E-mail: apelu@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Sambeth, Jorge E., E-mail: sambeth@quimica.unlp.edu.ar [Centro de Investigación y Desarrollo en Ciencias Aplicadas, “Dr. J. Ronco” CINDECA (CONICET CCT La Plata), 47 N°257, La Plata, Buenos Aires (Argentina); Thomas, Horacio J. [Pla.Pi.Mu-Planta Piloto Multipropósito, (CICPBA-UNLP) Cno. Centenario y 505, M.B. Gonnet, Buenos Aires (Argentina)

    2013-06-15

    Highlights: • Manganese oxides were synthesized using spent batteries as raw materials. • Spent alkaline and zinc–carbon size AA batteries were used. • A biohydrometallurgical process was employed to bio-lixiviate batteries. • Manganese oxides were active in the oxidation of VOCs (ethanol and heptane). - Abstract: Manganese, in the form of oxide, was recovered from spent alkaline and zinc–carbon batteries employing a biohydrometallurgy process, using a pilot plant consisting in: an air-lift bioreactor (containing an acid-reducing medium produced by an Acidithiobacillus thiooxidans bacteria immobilized on elemental sulfur); a leaching reactor (were battery powder is mixed with the acid-reducing medium) and a recovery reactor. Two different manganese oxides were recovered from the leachate liquor: one of them by electrolysis (EMO) and the other by a chemical precipitation with KMnO{sub 4} solution (CMO). The non-leached solid residue was also studied (RMO). The solids were compared with a MnO{sub x} synthesized in our laboratory. The characterization by XRD, FTIR and XPS reveal the presence of Mn{sub 2}O{sub 3} in the EMO and the CMO samples, together with some Mn{sup 4+} cations. In the solid not extracted by acidic leaching (RMO) the main phase detected was Mn{sub 3}O{sub 4}. The catalytic performance of the oxides was studied in the complete oxidation of ethanol and heptane. Complete conversion of ethanol occurs at 200 °C, while heptane requires more than 400 °C. The CMO has the highest oxide selectivity to CO{sub 2}. The results show that manganese oxides obtained using spent alkaline and zinc–carbon batteries as raw materials, have an interesting performance as catalysts for elimination of VOCs.

  8. Laminar Burning Velocities of Fuels for Advanced Combustion Engines (FACE) Gasoline and Gasoline Surrogates with and without Ethanol Blending Associated with Octane Rating

    Mannaa, Ossama

    2016-05-04

    Laminar burning velocities of fuels for advanced combustion engines (FACE) C gasoline and of several blends of surrogate toluene reference fuels (TRFs) (n-heptane, iso-octane, and toluene mixtures) of the same research octane number are presented. Effects of ethanol addition on laminar flame speed of FACE-C and its surrogate are addressed. Measurements were conducted using a constant volume spherical combustion vessel in the constant pressure, stable flame regime at an initial temperature of 358 K and initial pressures up to 0.6 MPa with the equivalence ratios ranging from 0.8 to 1.6. Comparable values in the laminar burning velocities were measured for the FACE-C gasoline and the proposed surrogate fuel (17.60% n-heptane + 77.40% iso-octane + 5% toluene) over the range of experimental conditions. Sensitivity of flame propagation to total stretch rate effects and thermo-diffusive instability was quantified by determining Markstein length. Two percentages of an oxygenated fuel of ethanol as an additive, namely, 60 vol% and 85 vol% were investigated. The addition of ethanol to FACE-C and its surrogate TRF-1 (17.60% n-heptane + 77.40% iso-octane + 5% toluene) resulted in a relatively similar increase in the laminar burning velocities. The high-pressure measured values of Markstein length for the studied fuels blended with ethanol showed minimal influence of ethanol addition on the flame’s response to stretch rate and thermo-diffusive instability. © 2016 Taylor & Francis.

  9. Recent Advances In Science Support For Isolated Droplet Combustion Experiments

    Dryer, F. L.; Kazakov, A.; Urban, B. D.; Kroenlein, K.

    2003-01-01

    In a joint program involving Prof. F.A. Williams of the University of California, San Diego and Dr. V. Nayagam of the National Center for Microgravity Research, the combustion characteristics of isolated liquid fuel droplets of n-heptane, n-decane, methanol, methanol-water, ethanol and ethanol-water having initial diameters between about 1 mm and 6 mm continues to be investigated. The objectives of the work are to improve fundamental knowledge of droplet combustion dynamics for pure fuels and fuel-water mixtures through microgravity experiments and theoretical analyses. The Princeton contributions support the engineering design, data analysis, and data interpretation requirements for the study of initially single component, spherically symmetric, isolated droplet combustion studies through experiments and numerical modeling. UCSD contributions are described in a companion communication in this conference. The Princeton effort also addresses the analyses of Fiber Supported Droplet Combustion (FSDC) experiments conducted with the above fuels and collaborative work with others who are investigating droplet combustion in the presence of steady convection. A thorough interpretation of droplet burning behavior for n-heptane and n-decane over a relatively wide range of conditions also involves the influences of sooting on the combustion behavior, and this particular aspect on isolated burning of droplets is under consideration in a collaborative program underway with Drexel University. This collaboration is addressed in another communication at this conference. The one-dimensional, time-dependent, numerical modeling approach that we have continued to evolve for analyzing isolated, quiescent droplet combustion data has been further applied to investigate several facets of isolated droplet burning of simple alcohols, n-heptane, and n-decane. Some of the new results are described below.

  10. Experimental determination of critical data of multi-component mixtures containing potential gasoline additives 2-butanol by a flow-type apparatus

    He, Maogang; Xin, Nan; Wang, Chengjie; Liu, Yang; Zhang, Ying; Liu, Xiangyang

    2016-01-01

    Graphical abstract: Experimental critical pressures of 2-butanol + hexane + heptane system. - Highlights: • Critical properties of six binary systems and two ternary systems were measured. • Six binary systems containing 2-butanol show non-ideal behavior in their T c –x 1 curves. • Non-ideal behavior of mixtures with 2-butanol relies on azeotropy. • Experimental data for binary systems were fitted well with Redlich–Kister equation. • Critical surfaces of ternary systems were plotted using the Cibulka’s expressions. - Abstract: In this work, we used a flow method for measurement of critical properties of six binary mixtures (2-butanol + cyclohexane, 2-butanol + hexane, 2-butanol + heptane, 2-butanol + octane, 2-butanol + nonane and 2-butanol + decane) and two ternary mixtures (2-butanol + hexane + heptane and 2-butanol + octane + decane). The critical properties were determined by observing the disappearance and reappearance of the gas–liquid phase meniscus in a quartz glass tube. The standard uncertainties of temperatures and pressures for both binary and ternary mixtures were estimated to be less than 0.2 K and 5.2 kPa, respectively. These critical data provide the boundaries of the two-phase regions of the related mixture systems. Six binary systems show non-ideal behaviors in the loci of critical temperatures. We used the Redlich–Kister equations to correlate the critical temperatures and pressures of these systems and listed the binary interaction parameters. The maximum average absolute deviation (AAD) of each binary system between experimental data and calculated results from Redlich–Kister equations is 0.038% for critical temperatures, and 0.244% for critical pressures. Moreover, the two ternary systems were newly reported and correlated by Cibulka’s and Singh’s expressions. The maximum AAD of critical temperatures and critical pressures are 0.103% and 0.433%, respectively.

  11. Fluid mechanics calculations in physics of droplets – IV: Head-on and off-center numerical collisions of unequal-size drops

    Alejandro Acevedo-Malavé

    2016-09-01

    Full Text Available In this study, the finite volume method is employed to simulate the coalescence collision between water drops immersed in a continuous phase (n-heptane. For that purpose, it is chosen a range of values for the velocity of collisions for the finite volume calculations may yield different possible outcomes of the collision process. It can be seen for head-on collisions that when the velocity of collision is 0.2 m/s and 3.5 m/s, the little drop induces the formation of a hole in the bigger drop, until the surface tension forces to restore the circular form of the resulting drop. For a velocity of collision of 16.0 m/s, the little drop deforms the bigger one, and the system is converted into a thin ligament with the evolution of the dynamics. In this case, a little mass of n-heptane is trapped between the two drops, but at the end of the dynamics it drains to the continuous phase. For off-center collisions, two different values for the velocity of collisions were chosen, and the drops exhibit a lot of waves on the droplets’ surface. The streamlines are calculated for the process of coalescence of drops. These streamlines allow the understanding of the dynamics of the droplets immersed on the n-heptane phase. The effect of the interfacial tension it is showed due to the oscillations that the droplet exhibits. When the coalescence has begun, the streamlines form circular patterns at the zone of contact between the drops which explain the increment of the thickness of the bridge structure of the fluid between the two drops. At the end of the dynamics, when the velocity is of 0.2 m/s, the bigger drop reaches a circular form approximately, but when the velocity is of 3.5 m/s the drop reaches an elongated form.

  12. Radioiodination of olive oil VIA iodinemonochloride and chloramine-T in organic medium

    Elwetery, A.S.; Elbayoumy, S.; Elgarhy, M.

    1992-01-01

    Olive oil is one of the neutral oils, composed of many fatty acids, some are saturated while others are unsaturated. This paper reports the results of comparative radioiodination study performed using iodine mono chloride I CI and chloramine-T as oxidising agents in organic solvents. On labelling using 125 I Cl in different solvents, benzene, petroleum ether, diethyl ether and n-heptane a yield of > 70% was found in case of diethyl ether within 5 minutes for olive oil while it was 80% for oleic acid under the same conditions. In case of benzene as a solvent the labelling yield was reached a maximum labelling of 37% and > 43% for olive oil and oleic acid respectively within 60 minutes after which labelling decreased with time. So benzene was chosen as the solvent for labelling of oleic acid using commercial 125 I Cl to compare with I CI prepared in the laboratory. Using unpurified commercial 125 I CI as labelling agent a yield of 65% was reached within 15 minutes while purified commercial I CI gave ∼ 40% after 15 minutes and 22% using the prepared 125 I CI. This reduction in the yield in case of purified I CI indicates that other iodine species I 2 , I - 3 and I OH plays great role in the labelling process depending on the medium used. Further studies were carried out using method for labelling olive oil as well as oleic acid in organic solvents n-heptane, benzene, acetone and methyl n-butyl ketone (MnBK) at a temperature just below the boiling point of each solvent. A maximum labelling yield of 28% for olive oil in the n-heptane solvent against 50% labelling yield of oleic acid under the same conditions of solvent, temperature and reaction time. Using actions as solvent it was found that the labelling yield decreases with reaction time.4 fig

  13. A reaction mechanism for gasoline surrogate fuels for large polycyclic aromatic hydrocarbons

    Raj, Abhijeet

    2012-02-01

    This work aims to develop a reaction mechanism for gasoline surrogate fuels (n-heptane, iso-octane and toluene) with an emphasis on the formation of large polycyclic aromatic hydrocarbons (PAHs). Starting from an existing base mechanism for gasoline surrogate fuels with the largest chemical species being pyrene (C 16H 10), this new mechanism is generated by adding PAH sub-mechanisms to account for the formation and growth of PAHs up to coronene (C 24H 12). The density functional theory (DFT) and the transition state theory (TST) have been adopted to evaluate the rate constants for several PAH reactions. The mechanism is validated in the premixed laminar flames of n-heptane, iso-octane, benzene and ethylene. The characteristics of PAH formation in the counterflow diffusion flames of iso-octane/toluene and n-heptane/toluene mixtures have also been tested for both the soot formation and soot formation/oxidation flame conditions. The predictions of the concentrations of large PAHs in the premixed flames having available experimental data are significantly improved with the new mechanism as compared to the base mechanism. The major pathways for the formation of large PAHs are identified. The test of the counterflow diffusion flames successfully predicts the PAH behavior exhibiting a synergistic effect observed experimentally for the mixture fuels, irrespective of the type of flame (soot formation flame or soot formation/oxidation flame). The reactions that lead to this synergistic effect in PAH formation are identified through the rate-of-production analysis. © 2011 The Combustion Institute.

  14. Thermodynamics and activity coefficients at infinite dilution for organic solutes and water in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide

    Domańska, Urszula; Lukoshko, Elena Vadimovna

    2014-01-01

    Highlights: • Measurements of activity coefficients at infinite dilution using GLC. • Sixty one organic solvents in the ionic liquid 1-butyl-1-methylmorpholinium tricyanomethanide. • High selectivity for heptane/thiophene, or pyridine, or 1-nitropropane. • The excess thermodynamic functions and the gas–liquid partition coefficients were presented. • Possible entrainer for the extraction of sulphur and nitrogen-compounds from alkanes. -- Abstract: The activity coefficients at infinite dilution, γ 13 ∞ , for 61 solutes, including alkanes, cycloalkanes, alkenes, alkynes, aromatic hydrocarbons, alcohols, water, thiophene, ethers, ketones, esters, aldehyde, acetonitrile, pyridine and 1-nitropropane in the ionic liquid (IL) 1-butyl-1-methylmorpholinium tricyanomethanide, [BMMOR][TCM] were determined by gas–liquid chromatography at six temperatures within the range of (318.15 to 368.15) K. The thermodynamic functions at infinite dilution as partial molar excess Gibbs free energy ΔG 1 E,∞ , enthalpy ΔH 1 E,∞ , and entropy term T ref ΔS 1 E,∞ were calculated from the experimental γ 13 ∞ values obtained over the temperature range. The density of [BMMOR][TCM] was measured over the temperature range (288.15 to 368.15) K. The gas–liquid partition coefficient K L was calculated for all solutes. The values of selectivity and capacity for a few separation problems such as hexane/benzene, cyclohexane/benzene, heptane/thiophene at T = 328.15 K were calculated from γ 13 ∞ and compared to literature values for similar ionic liquids, viz. N-methyl-2-pyrrolidinone (NMP), and sulfolane. In comparison with the previously measured values for [BMPYR][TCM], the morpholinium IL presents high selectivity for the separation of aromatic hydrocarbons from aliphatic hydrocarbons, and especially thiophene, or piridine from heptane with a slightly lower capacity. New data show that [BMMOR][TCM] IL may be proposed as an alternative solvent for the separation of

  15. Differential interactions of sex pheromone and plant odour in the olfactory pathway of a male moth.

    Nina Deisig

    Full Text Available Most animals rely on olfaction to find sexual partners, food or a habitat. The olfactory system faces the challenge of extracting meaningful information from a noisy odorous environment. In most moth species, males respond to sex pheromone emitted by females in an environment with abundant plant volatiles. Plant odours could either facilitate the localization of females (females calling on host plants, mask the female pheromone or they could be neutral without any effect on the pheromone. Here we studied how mixtures of a behaviourally-attractive floral odour, heptanal, and the sex pheromone are encoded at different levels of the olfactory pathway in males of the noctuid moth Agrotis ipsilon. In addition, we asked how interactions between the two odorants change as a function of the males' mating status. We investigated mixture detection in both the pheromone-specific and in the general odorant pathway. We used a recordings from individual sensilla to study responses of olfactory receptor neurons, b in vivo calcium imaging with a bath-applied dye to characterize the global input response in the primary olfactory centre, the antennal lobe and c intracellular recordings of antennal lobe output neurons, projection neurons, in virgin and newly-mated males. Our results show that heptanal reduces pheromone sensitivity at the peripheral and central olfactory level independently of the mating status. Contrarily, heptanal-responding olfactory receptor neurons are not influenced by pheromone in a mixture, although some post-mating modulation occurs at the input of the sexually isomorphic ordinary glomeruli, where general odours are processed within the antennal lobe. The results are discussed in the context of mate localization.

  16. Influence of Pt nanoparticles modified by La and Ce oxides on catalytic dehydrocyclization of n-alkanes

    A.H. Samia

    2015-06-01

    Full Text Available Catalytic reforming accounts for a large share of the world’s gasoline production, it is the most important source of aromatics for the petrochemical industry. In addition, reforming of hydrocarbon on the dual-function catalysts has been found to form fundamentally different products in hydrogen diluents. Typical catalysts employed for this reforming process are Pt/Al2O3 and Pt-M/Al2O3, M being the promoter. These solids are characterized by both acid and metal functions which catalyze dehydrocyclization, dehydrogenation, isomerization and cracking processes. In this regard, information about cerium and lanthanum, as promoters, is hardly revealed. The present work aims to study the performance of Pt/Al2O3 catalysts modified by lanthanum or cerium during the conversion of cyclohexane, n-hexane and n-heptane. Catalytic activities of the prepared catalysts were tested using a micro catalytic pulse technique. Physicochemical characterization of the solid catalysts such as, surface area (SBET, Fourier transform infrared (FTIR, differential scanning calorimetry (DSC, thermogravimetric analysis (TGA, hydrogen-temperature programed reduction (H2-TPR, hydrogen-temperature-programed desorption (H2-TPD, CO2-TPD, NH3-TPD, high resolution transmission electron microscopy (HRTEM and X-ray diffraction (XRD were depicted. Results indicated clearly that Pt/Al2O3 catalyst is selective toward dehydrogenation to benzene which could be explained as due to the decrease in the active acid sites and the comparative segregation of the alumina support especially at 3% load of CeO. The presence of La2O3 in the Pt/Al2O3 catalyst promotes aromatization of n-hexane and n-heptane, also the dehydrocyclization of n-hexane is more difficult than that of n-heptane. Thus, modification of the Pt/Al2O3 catalyst by La, resulted in a more active and selective reforming catalyst.

  17. Comparative study on sulphur reduction from heavy petroleum - Solvent extraction and microwave irradiation approach

    Mohammed, Abdullahi Dyadya; Isah, Abubakar Garba; Umaru, Musa; Ahmed, Shehu [Department of Chemical Engineering, Federal University of Technology, P.M.B 65, Minna (Nigeria); Abdullahi, Yababa Nma [National Petroleum Investment Management Services (Nigeria National Petroleum Corporation), Lagos (Nigeria)

    2012-07-01

    Sulphur- containing compounds in heavy crude oils are undesirable in refining process as they affect the quality of the final product, cause catalyst poisoning and deactivation in catalytic converters as well as causing corrosion problems in oil pipelines, pumps and refining equipment aside environmental pollution from their combustion and high processing cost. Sulphur reduction has being studied using microwave irradiation set at 300W for 10 and 15minutes and oxidative- solvent extraction method using n- heptane and methanol by 1:1, 1:2 and 1:3 crude- solvent ratios after being oxidized with hydrogen peroxide, H2O2 oxidants. Percentage sulphur removal with n- heptane solvent by 1:1 and 1:2 are 81.73 and 85.47%; but extraction using methanol by different observed ratios gave less sulphur reduction. Indeed when microwave irradiated at 300W for 10 and 15minutes, 53.68 and 78.45% reduction were achieved. This indicates that microwave irradiation had caused oxidation by air in the oven cavity and results to formation of alkyl radicals and sulphoxide from sulphur compound in the petroleum. The prevailing sulphur found in the crude going by FT-IR results is sulphides which oxidized to sulphoxide or sulphones. It is clear that sulphur extraction with heptane is more efficient than microwave irradiation but economically due to demands for solvent and its industrial usage microwave irradiation can serve as alternative substitute for sulphur reduction in petroleum. Sulphur reduction by microwave radiation should be up- scaled from laboratory to a pilot plant without involving extraction column in the refining.

  18. The Effect of Food-Simulating Agents on the Bond Strength of Hard Chairside Reline Materials to Denture Base Resin.

    Fatemi, Farzaneh Sadat; Vojdani, Mahroo; Khaledi, Amir Ali Reza

    2018-06-08

    To investigate the influence of food-simulating agents on the shear bond strength between direct hard liners and denture base acrylic resin. In addition, mode of failure was evaluated. One hundred fifty cylindrical columns of denture base resin were fabricated and bonded to three types of hard reline materials (Hard GC Reline, Tokuyama Rebase II Fast, TDV Cold Liner Rebase). Specimens of each reline material were divided into five groups (n = 10) to undergo 12-day immersion in distilled water, 0.02 N citric acid aqueous solution, heptane, and 40% ethanol/water solution at 37°C. The control group was not immersed in any solution. The shear bond strength test was performed, and the failure mode was determined. Statistics were analyzed with two-way ANOVA and chi-square test (α = 0.05). Significant interaction was found between the hard liners and food simulating agents (p < 0.001). The shear bond strength of Tokuyama in 40% ethanol and TDV in heptane decreased significantly (p = 0.001, p < 0.001 respectively); however, none of the solutions could significantly affect the shear bond strength of Hard GC Reline (p = 0.208). The mixed failure mode occurred more frequently in Hard GC Reline compared with the other liners (p < 0.001) and was predominant in specimens with higher bond strength values (p = 0.012). Food simulating agents did not adversely affect the shear bond strength of Hard GC Reline; however, ethanol and heptane decreased the bond strength of Tokuyama and TDV, respectively. These findings may provide support to dentists to recommend restricted consumption of some foods and beverages for patients who have to use dentures relined with certain hard liners. © 2018 by the American College of Prosthodontists.

  19. Analysis of non-phthalates plasticizers on porous graphitic carbon by supercritical fluid chromatography using evaporative light scattering detection.

    Vaccher, Claude; Decaudin, Bertrand; Sautou, Valérie; Lecoeur, Marie

    2014-09-12

    The analysis of several plasticizers, widely used in the production of medical devices, was investigated on porous graphitic carbon (PGC) stationary phase in supercritical fluid chromatography (SFC) with an evaporative light scattering detector (ELSD). Due to strong interaction of compounds with the PGC support, solvents of strong eluotropic strength were added to the CO2 supercritical fluid. The effect of alkyl chain (pentane, hexane, heptane) and chlorinated (CH2Cl2, CHCl3, CCl4) solvents was studied on the retention and on the ELSD detection of plasticizers. A co-solvent mixture composed of CHCl3/heptane, eluted under gradient mode, allowed a significant improvement of the ELSD response compared to the use of each solvent individually. Then, a central composite design (CCD) was implemented to optimize both the separation and the detection of plasticizers. The parameters involved were the outlet pressure, the gradient slope, the co-solvent composition and the drift tube temperature of the ELSD. After optimization, baseline separation of plasticizers was achieved in 7min and best signal-to-noise ratios were obtained with outlet pressure and drift tube temperature of ELSD set at 200bar and 31°C, respectively. The co-solvent mixture was also composed of CHCl3/heptane (35/65 v/v) and a gradient from 15 to 60% of co-solvent in 2.2min was employed. The results demonstrated that CCD is a powerful tool for the optimization of SFC/ELSD method and the response surface model analysis can provide statistical understandings of the significant factors required to achieve optimal separation and ELSD sensitivity. Copyright © 2014 Elsevier B.V. All rights reserved.

  20. Laminar Burning Velocities of Fuels for Advanced Combustion Engines (FACE) Gasoline and Gasoline Surrogates with and without Ethanol Blending Associated with Octane Rating

    Mannaa, Ossama; Mansour, Morkous S.; Roberts, William L.; Chung, Suk-Ho

    2016-01-01

    Laminar burning velocities of fuels for advanced combustion engines (FACE) C gasoline and of several blends of surrogate toluene reference fuels (TRFs) (n-heptane, iso-octane, and toluene mixtures) of the same research octane number are presented. Effects of ethanol addition on laminar flame speed of FACE-C and its surrogate are addressed. Measurements were conducted using a constant volume spherical combustion vessel in the constant pressure, stable flame regime at an initial temperature of 358 K and initial pressures up to 0.6 MPa with the equivalence ratios ranging from 0.8 to 1.6. Comparable values in the laminar burning velocities were measured for the FACE-C gasoline and the proposed surrogate fuel (17.60% n-heptane + 77.40% iso-octane + 5% toluene) over the range of experimental conditions. Sensitivity of flame propagation to total stretch rate effects and thermo-diffusive instability was quantified by determining Markstein length. Two percentages of an oxygenated fuel of ethanol as an additive, namely, 60 vol% and 85 vol% were investigated. The addition of ethanol to FACE-C and its surrogate TRF-1 (17.60% n-heptane + 77.40% iso-octane + 5% toluene) resulted in a relatively similar increase in the laminar burning velocities. The high-pressure measured values of Markstein length for the studied fuels blended with ethanol showed minimal influence of ethanol addition on the flame’s response to stretch rate and thermo-diffusive instability. © 2016 Taylor & Francis.

  1. Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds

    Miroslav Palík

    2014-09-01

    Full Text Available The study of Pd-catalysed cyclisation reactions of alkenols using different catalytic systems is reported. These transformations affect the stereoselective construction of mono- and/or bicyclic oxaheterocyclic derivatives depending on a starting alkenol. The substrate scope and proposed mechanism of Pd-catalysed cyclisation reactions are also discussed. Moreover, the diastereoselective Pd-catalysed cyclisation of appropriate alkenols to tetrahydrofurans and subsequent cyclisation provided properly substituted 2,5-dioxabicyclo[2.2.1]heptane and 2,6-dioxabicyclo[3.2.1]octane, respectively. Such bicyclic ring subunits are found in many natural products including ocellenynes and aurovertines.

  2. Two-stage Lagrangian modeling of ignition processes in ignition quality tester and constant volume combustion chambers

    Alfazazi, Adamu

    2016-08-10

    The ignition characteristics of isooctane and n-heptane in an ignition quality tester (IQT) were simulated using a two-stage Lagrangian (TSL) model, which is a zero-dimensional (0-D) reactor network method. The TSL model was also used to simulate the ignition delay of n-dodecane and n-heptane in a constant volume combustion chamber (CVCC), which is archived in the engine combustion network (ECN) library (http://www.ca.sandia.gov/ecn). A detailed chemical kinetic model for gasoline surrogates from the Lawrence Livermore National Laboratory (LLNL) was utilized for the simulation of n-heptane and isooctane. Additional simulations were performed using an optimized gasoline surrogate mechanism from RWTH Aachen University. Validations of the simulated data were also performed with experimental results from an IQT at KAUST. For simulation of n-dodecane in the CVCC, two n-dodecane kinetic models from the literature were utilized. The primary aim of this study is to test the ability of TSL to replicate ignition timings in the IQT and the CVCC. The agreement between the model and the experiment is acceptable except for isooctane in the IQT and n-heptane and n-dodecane in the CVCC. The ability of the simulations to replicate observable trends in ignition delay times with regard to changes in ambient temperature and pressure allows the model to provide insights into the reactions contributing towards ignition. Thus, the TSL model was further employed to investigate the physical and chemical processes responsible for controlling the overall ignition under various conditions. The effects of exothermicity, ambient pressure, and ambient oxygen concentration on first stage ignition were also studied. Increasing ambient pressure and oxygen concentration was found to shorten the overall ignition delay time, but does not affect the timing of the first stage ignition. Additionally, the temperature at the end of the first stage ignition was found to increase at higher ambient pressure

  3. Extraction of sulfuric acid with TOPO

    Shuyun, Xue; Yonghui, Yang; Yanzhao, Yang; Sixiu, Sun; Borong, Bao

    1998-01-01

    A study on solvent extraction of sulfuric acid by tri-octylphosphine oxide (TOPO) in n-heptane has been made. Extraction coefficients of H 2 SO 4 as a function of H 2 SO 4 concentration in aqueous phase, and extractant concentrations in organic phase have been studied. The composition of extracted species, equilibrium constants of extraction reaction have been evaluated. These results are important for interpreting extraction equilibrium data of uranium(VI) or other metal ions with TOPO in sulfuric acid media. (author)

  4. Studies on extraction of uranium (VI) with petroleum sulfoxides

    Yang Yanzhao; Sun Sixiu; Bao Borong

    1999-01-01

    The extraction of uranium(VI) with petroleum sulfoxides(PSO) in different diluents is studied. The extraction ability of U(VI) decreases in the following order: benzene, toluene, cyclohexane, heptane, kerosene, carbon tetrachloride and chloroform. The influence of the concentrations of nitric acid, PSO, salting out agent, complexing anion and temperature on the extraction equilibrium is also investigated, and the enthalpy of the extraction reaction is obtained. The relationship between the extraction equilibrium constants K ex and the physical parameters of diluents is derived. The extraction mechanism and equilibrium are examined by measurement of IR spectrophotometry

  5. Elucidation of the structure of organic solutions in solvent extraction by combining molecular dynamics and X-ray scattering

    Ferru, G.; Gomes Rodrigues, D.; Berthon, L.; Guilbaud, P.; Diat, O.; Bauduin, P.

    2014-01-01

    Knowledge of the supramolecular structure of the organic phase containing amphiphilic ligand molecules is mandatory for full comprehension of ionic separation during solvent extraction. Existing structural models are based on simple geometric aggregates, but no consensus exists on the interaction potentials. Herein, we show that molecular dynamics crossed with scattering techniques offers key insight into the complex fluid involving weak interactions without any long range ordering. Two systems containing mono- or diamide extractants in heptane and contacted with an aqueous phase were selected as examples to demonstrate the advantages of coupling the two approaches for furthering fundamental studies on solvent extraction. (authors)

  6. Distribution of MEG and methanol in well-defined hydrocarbon and water systems: Experimental measurement and modeling using the CPA EoS

    Riaz, Muhammad; Yussuf, Mustafe A.; Kontogeorgis, Georgios

    2013-01-01

    + water. These data are satisfactorily correlated (binaries) and predicted (ternaries) using Cubic Plus Association (CPA) equation of state (EoS). CPA is also applied to binary LLE of aromatic hydrocarbon + water and VLE of methane + methanol. Finally the distribution of water and inhibitors (methanol...... and MEG) in various phases is modeled using CPA. The hydrocarbon phase consists of mixture-1 (methane, ethane, n-butane) or mixture-2 (methane, ethane, propane, n-butane, n-heptane, toluene and n-decane). CPA can satisfactorily predict the water content in the gas phase of the multicomponent systems...

  7. Experimental ship fire measurements with simulated radioactive cargo

    Koski, J.A.; Arviso, M.; Bobbe, J.G.; Wix, S.D.; Cole, J.K.; Hohnstreiter, G.F.; Beene, D.E. Jr.

    1997-10-01

    Results from a series of eight test fires ranging in size from 2.2 to 18.8 MW conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages

  8. Experimental ship fire measurements with simulated radioactive cargo

    Koski, J.A.; Arvisol, M.; Bobbe, J.G.; Wix, S.D.; Cole, J.K.; Hohnstreiter, G.F.; Wix, S.D.; Beene, D.E.; Keane, M.P.

    1998-01-01

    Results from a series of eight test fires ranging in size from 2.2 to 18.8 MW conducted aboard the Coast Guard fire test ship Mayo Lykes at Mobile, Alabama are presented and discussed. Tests aboard the break-bulk type cargo ship consisted of heptane spray fires simulating engine room and galley fires, wood crib fires simulating cargo hold fires, and pool fires staged for comparison to land-based regulatory fire results. Primary instrumentation for the tests consisted of two pipe calorimeters that simulated a typical package shape for radioactive materials packages. (authors)

  9. 27 CFR 21.151 - List of denaturants authorized for denatured spirits.

    2010-04-01

    ..., liquid S.D.A. 36. Cedar leaf oil, U.S.P.XIII S.D.A. 38-B. Chloroform S.D.A. 20. Chlorothymol, N.F.XII S.D... (Glycerol), U.S.P S.D.A. 31-A. Green soap, U.S.P S.D.A. 27-B. Guaiacol, N.F.X S.D.A. 38-B. Heptane C.D.A. 18...) S.D.A. 45. Soap, hard, N.F.XI S.D.A. 31-A. Sodium iodide, U.S.P S.D.A. 25, 25-A. Sodium, metallic S...

  10. Experimental densities, refractive indices, and speeds of sound of 12 binary mixtures containing alkanes and aromatic compounds at T = 313.15 K

    Calvar, Noelia; Gomez, Elena; Gonzalez, Begona; Dominguez, Angeles

    2009-01-01

    Densities, speeds of sound, and refractive indices of 12 binary systems of alkanes (hexane, heptane, octane, and nonane) with aromatics (benzene, or toluene, or ethylbenzene) at T = 313.15 K and at atmospheric pressure were determined over the whole composition range, and are presented in this paper. From the experimental results, the derived and excess properties (isentropic compressibility, excess molar volumes, and excess molar isentropic compressibility) at T = 313.15 K were calculated and satisfactorily fitted to the Redlich-Kister equation.

  11. Study of the hydro-isomerization of paraffins with 7 and 8 carbon atoms on bifunctional catalysts; Etude de l'hydroisomerisation des paraffines a 7 et 8 atomes de carbone sur catalyseurs bifonctionnels

    Patrigeon, A.

    2000-10-11

    Due to the suppression of lead additives and the trend to decrease the aromatic and olefinic content in gasoline, the interest for new octane enhancement processes has increased, particularly for isomerization of C{sub 7} and C{sub 8} linear paraffins into higher octane number multi-branched paraffins. Up to the present day, no industrial bifunctional catalyst exists due to the high tendency of the paraffins to be cracked limiting the amount of multi-branched products. The aim of this work is to study the possibility of isomerizing linear C{sub 7} and C{sub 8} paraffins in two steps in order to increase the amount of formed multi-branched paraffins. The first step converts linear paraffins into mono-branched paraffins (that step is supposed to be the slowest one) carried out using one bifunctional catalyst. The second step converts the formed mono-branched paraffins into multi-branched paraffins using a second bifunctional catalyst. The aim is to determine the characteristics of the two catalysts. To study the first step, Pt/zeolite or Pt/meso-porous solid catalysts, with different acidities and porosities, were tested in n-heptane and n-octane hydro-conversion. The role of solid porosity on selectivities was clearly established. Molecular modelling was utilised to explain the observed selectivities. To study the second step, the 2-methyl-hexane and 2-methyl-heptane hydro-conversion on Pt/H-beta and Pt/H-Y was carried out. This lead to maximum multi-branched yields similar to those obtained with the n-heptane and n-octane hydro-conversion. That result shows that the two steps isomerization process is not necessarily required because no more multi-branched products are formed. A kinetic study on the n-heptane hydro-conversion was performed. The decomposition of isomerization and cracking reactions into elementary steps has shown the major role of the paraffins physio-sorption step in the zeolite pores. (author)

  12. Solution growth and scintillation properties of 9-phenylcarbazole

    van Loef, Edgar V.; Markosyan, Gary; Shirwadkar, Urmila; McClish, Mickel; Shah, Kanai S.

    2017-12-01

    In this paper we report on the crystal growth and characterization of 9-phenylcarbazole (PCz). Crystals of PCz were obtained by the solution growth technique. Several organic solvents were investigated including heptane, cyclohexane, toluene, xylene, methanol, ethanol, and acetone. The largest crystals of the highest quality were grown from acetone. Radioluminescence spectra of pure PCz crystals exhibit a broad emission band peaking at 381 nm. Adding a small amount of an impurity (dopant) shifts the emission wavelength to 446 nm which is a better match to standard bialkali photomultiplier tubes. Single crystals of pure PCz have low light yields (typically security, nuclear non-proliferation, nuclear physics, and non-destructive testing.

  13. Catalytic Alkylation of 2-Methylfuran with Formalin Using Supported Acidic Ionic Liquids

    Li, Hu; Shunmugavel, Saravanamurugan; Yang, Song

    2015-01-01

    to form a biphasic system. The reactivity of other biomass-based substrates such as 3,4-dimethoxybenzaldehyde, furfural, glycolaldehyde, and glyceraldehyde was also investigated over acidic SILCs, and excellent yields of about 80% or higher were obtained of the corresponding condensed products (except...... from glyceraldehyde). Easy catalyst recovery from the aqueous phase after extraction of BMFM with n-heptane and reusability for at least five consecutive reaction runs without significant loss of catalyst activity was further exemplified for a selected catalyst....

  14. Síntese do butirato de n-butila empregando lipase microbiana imobilizada em copolímero de estireno-divinilbenzeno Synthesis of butyl butyrate by microbial lipase immobilized onto styrene-divinylbenzene copolymer

    Pedro Carlos de Oliveira

    2000-10-01

    Full Text Available This work investigates the reaction parameters of an immobilized lipase in the esterification reaction of n-butanol and butyric acid. Microbial lipase from Candida rugosa was immobilized onto styrene-divinylbenzene copolymer (STY-DVB and subsequently introduced in an organic medium containing substrates in appropriate concentrations. Heptane was selected as solvent on the basis of its compatibility with the resin and the enzyme. The influence of molar ratio of acid to alcohol, amount of immobilized lipase and temperature on the butyl butyrate formation was determined. The results were compared with those achieved with free lipase and Lipozyme (commercially immobilized lipase under the same operational conditions.

  15. Untersuchungen zum atmosphärenchemischen Abbau langkettiger Aldehyde

    Plagens, Heike

    2001-01-01

    In dieser Arbeit wurden die bimolekularen Geschwindigkeitskonstanten für die Reaktionen von Hexanal, Heptanal, Oktanal und Nonanal mit OH and Cl Radikalen bei (298 ± 2) K und (1000 ± 20) mbar experimentell bestimmt. Ebenso wurde die Chlorgeschwindigkeitskonstante für Butanal gemessen. Die Werte sind (in Einheiten von cm3 Molekül-1 s-1) in Tabelle 1 zusammengefaßt. Tabelle 1: Aldehyde kOH kCl Butanal - (2,21 ± 0,16) · 10-10 Hexan...

  16. Oxidative desulfurization of thiophene on TiO2/ZSM-12 zeolite

    Santos,Marília Ramalho Figueiredo dos; Pedrosa,Anne Michelle Garrido; Souza,Marcelo José Barros de

    2016-01-01

    In this work the hydrothermal synthesis of ZSM-12 zeolite was performed, varying the MTEACl/SiO2 ratio, where the synthesis temperature was 140 ºC and the crystallization time was 144 hours. The catalysts were characterized by XRD, FTIR and TG. TiO2/ZSM-12 catalysts were used with titanium ions concentrations of 5, 10 and 15%. The oxidative desulfurization (ODS) reactions were performed using a model mixture containing n-heptane as solvent and thiophene as sulfur compound, H2O2 as an oxidizin...

  17. Power and Thermal Technologies for Air and Space -- Scientific Research Program. Delivery Order 0016: Developing and Processing High Energy Density Polymer Film Dielectrics for High Temperature Air Force Power Electronic Applications

    2010-01-01

    residue was recrystallized from 300 ml hot heptane. A yield of 2 g was obtained, m.pt., 230-232˚C. The batch of FDAPE polymer utilized in the wide...solution was added to a large excess of methanol to precipitate the polymer. After soxhlet extraction with methanol and vacuum drying, the polymer was...hours. The yield of the polymer was 1.6 g (94 percent). An intrinsic viscosity of 0.66 dl/g was measured for the polymer in N-methylpyrrolidone (NMP

  18. Relation Between Acid and Catalytic Properties of Chlorinated Gamma-Alumina. a 31p Mas Nmr and Ftir Investigation

    Guillaume D.

    1999-07-01

    Full Text Available In this paper, we have studied the effect of chlorine on the surface properties of gamma-alumina, especially on their acid properties. The use of FTIR spectroscopy and 31P MAS NMR of adsorbed trimethylphosphine allows to propose a chlorination mechanism. To correlate the surface properties of these chlorinated gamma-alumina with their catalytic properties, we have used a model reaction, the cracking of n-heptane under reforming conditions. The analysis of the correlation between acid properties determined by 31P MAS NMR and the catalytic results (in terms of activities and selectivities allows to identify which sites are involved in the cracking reaction.

  19. The kinetics of fossil resin extraction from a flotation concentrate

    Li, L.; Yu, Q.; Miller, J.D. [Univ. of Utah, Salt Lake City, UT (United States)

    1995-11-01

    The kinetics of fossil resin extraction from a flotation concentrate by heptane were investigated as a function of process variables using monosize particles. Experimental results provide for a better understanding of the refining process and the basis for subsequent design and construction of a continuous resin refining circuit. Based on the effect of process variables (particle size, stirring speed, and temperature) the resin extraction rate appears to be controlled by surface solvation phenomena. The initial extraction rate was found to be inversely proportional to the initial particle size and a kinetic model is being developed to describe the experimental results.

  20. Formation of La3+, Pr3+, Eu3+, Er3+, and Lu3+ complexes with chloride ions, in aqueous medium

    Fernandez R, E.; Jimenez R, M.; Solache R, M.

    2007-01-01

    The constants of stability of the complexes of La 3+ , Pr 3+ , Eu 3+ , Er 3+ , and Lu 3+ with Cl - ions, its were determined, in the aqueous medium of HCI - HClO 4 and by a solvent extraction method. The dinonyl naphtalene sulfonic acid in n-heptane was used as extractant. The lanthanides concentration, it was measured by a VIS spectrophotometry method and by another radiochemical. The ions specific interaction theory (SIT) it was used for the extrapolation to ionic force 0 M. The results indicate that the stability constants of the LnCI 2+ species diminishes when increasing the ion force and the charge density. (Author)

  1. Effects of gamma irradiation on antioxidants and ultraviolet stabilizers

    Kawamura, Yoko; Miura, Makiko; Miura, Yukiko; Yamada, Takashi

    1998-01-01

    The effects of gamma irradiation on 18 kinds of antioxidants and 10 kinds of ultraviolet stabilizers, intact or in a polyethylene sheet, were studied. After irradiating at a 30kGy dose, the content of additives themselves did not change and new degradation products were not found. While most antioxidants in polyethylene had a decreased content after irradiation, most ultraviolet stabilizers did not change. During the migration tests with aqueous food simulants, additives were not released from either irradiated or unirradiated sheets. For the migration tests with n-heptane, however, all additives were released from the unirradiated sheet, while most of the antioxidants were not released or released only slightly. (author)

  2. Separation of Asphaltenes by Polarity using Liquid-Liquid Extraction

    Andersen, Simon Ivar

    1997-01-01

    In order to investigate the nature of petroleum asphaltenes in terms of polarity a process was developed using initial liquid-liquid extraction of the oil phase followed by precipitation of the asphaltenes using n-heptane. The liquid-liquid extraction was performed using toluene-methanol mixtures...... phase. The asphaltenes were analysed using FTir, Elemental analysis, and HPLC-SEC with a diode array detector. With increasing content of toluene in the methanol the molecular weight distribution of the asphaltenes significantly move to higher molecular weights. The content of nitrogen and sulfur...

  3. Determinação do coeficiente de atividade em diluição infinita de hidrocarbonetos em furfural a 298,15 K por SPME-GC/FID

    Filipe Arantes Furtado

    2010-01-01

    Full Text Available In this work a new method (SPME-GC/FID was developed to analyze the activity of binary liquid mixtures. The purpose is to demonstrate that SPME is capable to be used to determinate activity coefficients at infinite dilution knowing the fiber properties, with a lower cost than the conventional methods encountered in literature such as GLC. The activity coefficients at infinite dilution in furfural for n-hexane, n-heptane and cyclohexane at 298.15 K was determined using SPME and deviations of literature data was about 7%.

  4. Army Research Office and Air Force Office of Scientific Research Contractors’ Meeting in Chemical Propulsion Held in Boulder, Colorado on June 11-13, 2007

    2007-06-01

    Hanson, "Methyl Concentration Time Histories during iso -Octane and n-Heptane Oxidation," Proceedings of the Combustion Institute 31, 321-328, 2007. T...1000 -700 -400 -100 200 500 800 Temperature(K): 300 700 1100 1500 1900 2300 27000 . A l/ 0.1 0.60.0 OWN 00,o2 a3 0 0 . . . o’.4 0 0.1 02 o0. 0.4 x(m...reproduce extinction and autoignition characteristics of JP-8. A surrogate made up of n-decane (60 %) and iso -octane (40 %) by liquid volume best

  5. Thermodynamics of Triethylene Glycol and Tetraethylene Glycol Containing Systems Described by the Cubic-Plus-Association Equation of State

    Breil, Martin Peter; Kontogeorgis, Georgios

    2009-01-01

    A thorough investigation of triethylene glycol (TEG) containing systems has been performed. The introduction of a new six-site association scheme for the TEG molecule has shown to be advantageous. Glycols are often modeled using a four-site scheme (abbreviated as 4C) hence ignoring the internal...... lone pairs of oxygen. The new association scheme also takes these sites into account. The new parameters of TEG are based on the vapor pressure data, liquid density data, and liquid-liquid equilibria (LLE) data (n-heptane), and they are tested for binary systems (methane, n-octane, n-nonane, n...

  6. Development and validation of a generic reduced chemical kinetic mechanism for CFD spray combustion modelling of biodiesel fuels

    Cheng, Xinwei; Ng, Hoon Kiat; Ho, Jee Hou

    2015-01-01

    In this reported work, a generic reduced biodiesel chemical kinetic mechanism, with components of methyl decanoate (C11H22O2, MD), methyl-9-decenoate (C11H20O2, MD9D) and n-heptane (C7H16) was built to represent the methyl esters of coconut, palm, rapeseed and soybean. The reduced biodiesel...... and detailed mechanism predictions, for each zero-dimensional (0D) auto-ignition and extinction process using CHEMKIN-PRO. Maximum percentage errors of less than 40.0% were recorded when the predicted ignition delay (ID) periods for coconut, palm, rapeseed and soybean methyl esters were compared to those...

  7. A Novel Non-Toxic Xylene Substitute (SBO) for Histology

    Kunhua, Wang; Chuming, Fan; Tao, Lai; Yanmei, Yang; Xin, Yang; Xiaoming, Zhang; Xuezhong, Guo; Xun, Lai

    2011-01-01

    Xylene has been generally used as a clearing and deparaffinizing agent in histology. Because of the potential toxic and flammable nature of xylene, its substitutes have been introduced into some laboratories. In this study, we introduced a novel, non-toxic xylene substitute (SBO), which was generated through a mixture of 86% of white oil No.2 and 14% of N-heptane. SBO had a high boiling point (188°C) and flash point (144°C) coupled with a scentless and decreased volatility. To compare the eff...

  8. Engineering development of selective agglomeration: Task 5, Bench- scale process testing

    1991-09-01

    Under the overall objectives of DOE Contract Engineering Development of Selective Agglomeration,'' there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

  9. Engineering development of selective agglomeration: Task 5, Bench- scale process testing

    1991-09-01

    Under the overall objectives of DOE Contract ``Engineering Development of Selective Agglomeration,`` there were a number of specific objectives in the Task 5 program. The prime objectives of Task 5 are highlighted below: (1) Maximize process performance in pyritic sulfur rejection and BTU recovery, (2) Produce a low ash product, (3) Compare the performance of the heavy agglomerant process based on diesel and the light agglomerant process using heptane, (4) Define optimum processing conditions for engineering design, (5) Provide first-level evaluation of product handleability, and (6) Explore and investigate process options/ideas which may enhance process performance and/or product handleability.

  10. Selective nonspecific solvation under dielectric saturation and fluorescence spectra of dye solutions in binary solvents.

    Bakhshiev, N G; Kiselev, M B

    1991-09-01

    The influence of selective nonspecific solvation on the fluorescence spectra of three substitutedN-methylphthalimides in a binary solvent system consisting of a nonpolar (n-heptane) and a polar (pyridine) component has been studied under conditions close to dielectric saturation. The substantially nonlinearity of the effect is confirmation that the spectral shifts of fluorescence bands depend on the number of polar solvent molecules involved in solvating the dye molecule. The measured fluorescence spectral shifts determined by substituting one nonpolar solvent molecula with a polar one in the proximity of the dye molecule agree quantitatively with the forecasts of the previously proposed semiempirical theory which describes this nonlinear solvation phenomenon.

  11. Scale-up of counter-current chromatography: demonstration of predictable isocratic and quasi-continuous operating modes from the test tube to pilot/process scale.

    Sutherland, Ian; Hewitson, Peter; Ignatova, Svetlana

    2009-12-11

    Predictable scale-up from test tube derived distribution ratios and analytical-scale sample loading optimisation is demonstrated using a model sample system of benzyl alcohol and p-cresol in a heptane:ethyl acetate:methanol:water phase system with the new 18 L Maxi counter-current chromatography centrifuge. The versatility of having a liquid stationary phase with its high loading capacity and flexible operating modes is demonstrated at two different scales by separating and concentrating target compounds using a mixture of caffeine, vanillin, naringenin and carvone using a quasi-continuous technique called intermittent counter-current extraction.

  12. Trapping of palindromic ligands within native transthyretin prevents amyloid formation

    Kolstoe, Simon E.; Mangione, Palma P.; Bellotti, Vittorio; Taylor, Graham W.; Tennent, Glenys A.; Deroo, Stéphanie; Morrison, Angus J.; Cobb, Alexander J. A.; Coyne, Anthony; McCammon, Margaret G.; Warner, Timothy D.; Mitchell, Jane; Gill, Raj; Smith, Martin D.; Ley, Steven V.

    2010-01-01

    Transthyretin (TTR) amyloidosis is a fatal disease for which new therapeutic approaches are urgently needed. We have designed two palindromic ligands, 2,2'-(4,4'-(heptane-1,7-diylbis(oxy))bis(3,5-dichloro-4,1-phenylene)) bis(azanediyl)dibenzoic acid (mds84) and 2,2'-(4,4'-(undecane-1,11-diylbis(oxy))bis(3,5-dichloro-4,1-phenylene)) bis(azanediyl)dibenzoic acid (4ajm15), that are rapidly bound by native wild-type TTR in whole serum and even more avidly by amyloidogenic TTR variants. One to one...

  13. Study of Asphaltene Solutions by Electrical Conductivity Measurements Conductivité électrique des solutions d'asphaltènes

    Behar E.

    2006-11-01

    Full Text Available The asphaltene interactions in model solutions were studied using a technique based on the electrical conductivity measurement. Interactions with n-heptane, resins, surfactants, water, phenol and NaCI were investigated. The conclusions drawn from this study confirmed previous opinions on aggregation mechanism of asphaltenes in solutions. They confirmed also the interpretation of asphaltene behaviour in terms of colloidal solution theories. Les interactions des asphaltènes avec leur environnement moléculaire dans des solutions modèles ont été étudiées par la mesure de la conductivité électrique de ces solutions. Les interactions avec le n-heptane, des résines, des tensioactifs, l'eau, le phénol et le chlorure de sodium ont été explorées. Les conclusions tirées de cette étude ont confirmé certaines hypothèses faites sur les mécanismes d'agrégation des asphaltènes en solution, en particulier dans le cadre de la théorie des solutions colloïdales.

  14. Thermal desorption (TD) study of heterogeneous catalytic reactions--4. Nonuniformity of Pt/. gamma. -Al/sub 2/O/sub 3/ catalysts

    Rozanov, V V [Inst. Chem. Phys. Acad. Sci. U.S.S.R.; Sklyarov, A V; Gland, J

    1979-10-01

    Programed TD of n-heptane adsorbed on 0.6-3% by wt Pt/..gamma..-Al/sub 2/O/sub 3/ laboratory catalysts with different dispersities of the metallic phase showed the formation of toluene at 160/sup 0/-260/sup 0/C with spectral maxima at about 200/sup 0/ and 230/sup 0/C and a benzene desorption maxima at 300/sup 0/C. The desorption of both benzene and the high-temperature form of toluene decreased with decreased dispersity of the catalyst and was not observed with the catalyst characterized by an average Pt particle size of 1000 A. Toluene adsorbed on the same catalysts showed a TD peak of benzene at 300/sup 0/C. With commercial Pt/Al/sub 2/O/sub 3/ reforming catalysts, up to five toluene desorption peaks were observed at 200/sup 0/-360/sup 0/C, suggesting the presence of active sites with different activities and concentrations on the catalyst surface. Experiments on TD of deuterated n-heptane suggested different reaction mechanisms associated with different types of active sites and the formation of low- and high-temperature forms of toluene. Only the latter had a maximum coinciding with a TD peak of D/sub 2/ (240/sup 0/C), probably formed by dehydrogenation of adsorbed diene or olefin intermediates.

  15. Catalytic behavior of Pt nanoparticles dealuminated Y-zeolite for some n-alkane hydroisomerization

    S.A. Hanafi

    2014-06-01

    Full Text Available Dealuminated zeolite Y-supported platinum was prepared adopting two dealumination methods, viz. fast (1, 3 and 6 h and slow method (18 h. The content of Pt was constant at 0.5 wt% in all investigated catalysts. The prepared samples were characterized using TGA/DSC, XRD, FTIR techniques, nitrogen adsorption at −196 °C and TEM-connected with energy dispersive spectroscopy (EDS. Surface acidity was investigated via pyridine adsorption using FT-IR spectroscopy. The parent and dealuminated Y-zeolite samples were characterized by their microporous system. By increasing the dealumination time to 6 h, the increased specific surface area and total pore volume indicated a sort of pore opening taking place with an increase in the accessibility of nitrogen molecules. DSC confirmed the thermal stability of the dealuminated zeolite samples up to 800 °C. The prepared catalysts were tested through hydroisomerization reactions of n-hexane and n-heptane using a micro-catalytic pulse technique. Different catalytic behaviors could be distinguished for the dealuminated samples based on competitive reactions; hydro-isomerization, hydrocracking and cyclization. Slow dealumination leads to the most selective catalysts for hydroisomerization. n-Heptane was converted to higher extent than n-hexane; cracking process was more evident when the former was fed to the reactor.

  16. A computational investigation of diesel and biodiesel combustion and NOx formation in a light-duty compression ignition engine

    Wang, Zihan [Mississippi State Univ., Mississippi State, MS (United States). Dept. of Mechanical Engineering; Srinivasan, Kalyan K. [Mississippi State Univ., Mississippi State, MS (United States). Dept. of Mechanical Engineering; Krishnan, Sundar R. [Mississippi State Univ., Mississippi State, MS (United States). Dept. of Mechanical Engineering; Som, Sibendu [Argonne National Lab. (ANL), Argonne, IL (United States). Center for Transportation Research

    2012-04-24

    Diesel and biodiesel combustion in a multi-cylinder light duty diesel engine were simulated during a closed cycle (from IVC to EVO), using a commercial computational fluid dynamics (CFD) code, CONVERGE, coupled with detailed chemical kinetics. The computational domain was constructed based on engine geometry and compression ratio measurements. A skeletal n-heptane-based diesel mechanism developed by researchers at Chalmers University of Technology and a reduced biodiesel mechanism derived and validated by Luo and co-workers were applied to model the combustion chemistry. The biodiesel mechanism contains 89 species and 364 reactions and uses methyl decanoate, methyl-9- decenoate, and n-heptane as the surrogate fuel mixture. The Kelvin-Helmholtz and Rayleigh-Taylor (KH-RT) spray breakup model for diesel and biodiesel was calibrated to account for the differences in physical properties of the fuels which result in variations in atomization and spray development characteristics. The simulations were able to capture the experimentally observed pressure and apparent heat release rate trends for both the fuels over a range of engine loads (BMEPs from 2.5 to 10 bar) and fuel injection timings (from 0° BTDC to 10° BTDC), thus validating the overall modeling approach as well as the chemical kinetic models of diesel and biodiesel surrogates. Moreover, quantitative NOx predictions for diesel combustion and qualitative NOx predictions for biodiesel combustion were obtained with the CFD simulations and the in-cylinder temperature trends were correlated to the NOx trends.

  17. Computational Study on Spirocyclic Compounds as Energetic Materials (I)

    Seok, Won K. [Dongguk Univ., Seoul (Korea, Republic of)

    2014-04-15

    The molecular structures of 2,6-diaza-1,3,5,7-tetraoxaspiro heptane and its dinitro derivative, 2,6-dinitro-2,6-diaza-1,3,5,7-tetraoxaspiro heptane, were fully optimized without symmetry constraints at HF/6-31G level of theory. A bisected conformation with respect to the ring is preferred with a C{sub 2} symmetric structure. The density of each molecule in the crystalline state was estimated to 1.12 and 2.36 g/cm{sup 3} using PM3/VSTO-3G calculations from the molecular volume. The heat of formation was calculated for two compounds at the CBS-4M level of theory. The detonation parameters were computed using the EXPLO5 software: D = 6282 m/s, P{sub C-J} = 127 kbar for compound, D = 7871 m/s, P{sub C-J} = 307 kbar for compound, and D = 6975 m/s, P{sub C-J} = 170 kbar for 60% compound with 40% TNT. Specific impulse of compound 1 in aluminized formulation when used as monopropellants was very similar to that of the conventional ammonium perchlorate in the same formulation of aluminum.

  18. Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO2 and Al2O3

    Contreras, J.L.; Fuentes, G.A.; Navarrete, J.; Vazquez, A.; Zeifert, B.; Salmones, J.; Nuno, L.

    2010-01-01

    The effect of the Bronsted/Lewis acid ratio on isomerization of n-heptane using Al 2 O 3 as a source of Lewis acidity and WOx/ZrO 2 as a source of Bronsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W=O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Bronsted acidity of the WOx/ZrO 2 domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO 2 explain this catalytic behavior.

  19. Structural and catalytic characterization of mechanical mixtures of Pt/WOx-ZrO{sub 2} and Al{sub 2}O{sub 3}

    Contreras, J.L., E-mail: jlcl@correo.azc.uam.m [Universidad Autonoma Metropolitana-Azcapotzalco, CBI, Dpto. Energia, Av. Sn. Pablo 180, Col. Reynosa, C.P. 02200, Mexico, DF (Mexico); Fuentes, G.A. [Universidad Autonoma Metropolitana-Iztapalapa, CBI, Depto. de IPH C.P. 09340, Mexico, DF (Mexico); Navarrete, J.; Vazquez, A. [Instituto Mexicano del Petroleo, IBP, Ger. de Catalizadores, Eje Central Lazaro Cardenas No. 152, C.P. 07300, Mexico, DF (Mexico); Zeifert, B.; Salmones, J. [Instituto Politecnico Nacional Mexico, ESIQIE, Laboratorio de Catalisis y Materiales, C.P. 07738, Mexico, DF (Mexico); Nuno, L. [Universidad Autonoma Metropolitana-Azcapotzalco, CBI, Dpto. Energia, Av. Sn. Pablo 180, Col. Reynosa, C.P. 02200, Mexico, DF (Mexico)

    2010-04-16

    The effect of the Bronsted/Lewis acid ratio on isomerization of n-heptane using Al{sub 2}O{sub 3} as a source of Lewis acidity and WOx/ZrO{sub 2} as a source of Bronsted and Lewis acidity was studied and controlled using mechanical mixtures of these solids. These mixtures were characterized by surface area, infrared spectroscopy of pyridine, X-ray diffraction and Raman spectroscopy. It was found that the presence of W=O stretching mode which was consistent with the presence of oxotungstate species which were the precursors of the acid sites. It was found out that as the oxotungstate structures increased, the selectivity to n-heptane isomers increased while the hydrocracking and dehydrocyclization selectivity decreased. The presence of Bronsted acidity of the WOx/ZrO{sub 2} domains, the increase of Knudsen diffusivity and the loss of Pt metallic area by strong interaction of the Pt with the WOx/ZrO{sub 2} explain this catalytic behavior.

  20. A path flux analysis method for the reduction of detailed chemical kinetic mechanisms

    Sun, Wenting; Ju, Yiguang [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States); Chen, Zheng [State Key Laboratory for Turbulence and Complex Systems, College of Engineering, Peking University, Beijing 100871 (China); Gou, Xiaolong [School of Power Engineering, Chongqing University, Chongqing 400044 (China)

    2010-07-15

    A direct path flux analysis (PFA) method for kinetic mechanism reduction is proposed and validated by using high temperature ignition, perfect stirred reactors, and steady and unsteady flame propagations of n-heptane and n-decane/air mixtures. The formation and consumption fluxes of each species at multiple reaction path generations are analyzed and used to identify the important reaction pathways and the associated species. The formation and consumption path fluxes used in this method retain flux conservation information and are used to define the path indexes for the first and the second generation reaction paths related to a targeted species. Based on the indexes of each reaction path for the first and second generations, different sized reduced chemical mechanisms which contain different number of species are generated. The reduced mechanisms of n-heptane and n-decane obtained by using the present method are compared to those generated by the direct relation graph (DRG) method. The reaction path analysis for n-decane is conducted to demonstrate the validity of the present method. The comparisons of the ignition delay times, flame propagation speeds, flame structures, and unsteady spherical flame propagation processes showed that with either the same or significantly less number of species, the reduced mechanisms generated by the present PFA are more accurate than that of DRG in a broad range of initial pressures and temperatures. The method is also integrated with the dynamic multi-timescale method and a further increase of computation efficiency is achieved. (author)

  1. Authentication of fattening diet of Iberian pigs according to their volatile compounds profile from raw subcutaneous fat.

    Narváez-Rivas, M; Pablos, F; Jurado, J M; León-Camacho, M

    2011-02-01

    The composition of volatile components of subcutaneous fat from Iberian pig has been studied. Purge and trap gas chromatography-mass spectrometry has been used. The composition of the volatile fraction of subcutaneous fat has been used for authentication purposes of different types of Iberian pig fat. Three types of this product have been considered, montanera, extensive cebo and intensive cebo. With classification purposes, several pattern recognition techniques have been applied. In order to find out possible tendencies in the sample distribution as well as the discriminant power of the variables, principal component analysis was applied as visualisation technique. Linear discriminant analysis (LDA) and soft independent modelling by class analogy (SIMCA) were used to obtain suitable classification models. LDA and SIMCA allowed the differentiation of three fattening diets by using the contents in 2,2,4,6,6-pentamethyl-heptane, m-xylene, 2,4-dimethyl-heptane, 6-methyl-tridecane, 1-methoxy-2-propanol, isopropyl alcohol, o-xylene, 3-ethyl-2,2-dimethyl-oxirane, 2,6-dimethyl-undecane, 3-methyl-3-pentanol and limonene.

  2. Physical properties of {anisole + n-alkanes} at temperatures between (293.15 and 303.15) K

    Al-Jimaz, Adel S.; Al-Kandary, Jasem A.; Abdul-latif, Abdul-Haq M.; Al-Zanki, Adnan M.

    2005-01-01

    Density ρ, viscosity η, and refractive index n D , values of {anisole + hexane, or heptane, or octane, or nonane, or decane, or dodecane} binary mixtures over the entire range of mole fraction at temperatures (293.15, 298.15, and 303.15) K, have been investigated at atmospheric pressure. The excess molar volume V E , has been calculated from the experimental measurements. These results were fitted to Redlich and Kister polynomial equation to estimate the binary interaction parameters. The viscosity data were correlated with equations of Grunberg and Nissan, and McAllister. The refractive indices data were used to calculate the specific refractivity R 12 , and also correlated with Lorentz-Lorenz equation. While the excess molar volumes of {anisole + hexane} are negative, and {anisole + heptane} are sigmoidal S-shaped, the remaining binary mixtures are positive. The effects of n-alkanes chain length as well as the temperature on the excess molar volume have been studied. The calculated values have been qualitatively used to explain the intermolecular interaction between the mixing components

  3. Olfaction in the boll weevil,Anthonomus grandis Boh. (Coleoptera: Curculionidae): Electroantennogram studies.

    Dickens, J C

    1984-12-01

    Electroantennogram (EAG) techniques were utilized to measure the antennal olfactory responsiveness of adult boll weevils,Anthonomus grandis Boh. (Coleoptera: Curculionidae), to 38 odorants, including both insect and host plant (Gossypium hirsutum L.) volatiles. EAGs of both sexes were indicative of at least two receptor populations: one receptor population primarily responsive to pheromone components and related compounds, the other receptor population primarily responsive to plant odors. Similar responses to male aggregation pheromone components (i.e., compounds I, II, and III + IV) were obtained from both sexes, but females were slightly more sensitive to I. Both sexes were highly responsive to components of the "green leaf volatile complex," especially the six-carbon saturated and monounsaturated primary alcohols. Heptanal was the most active aldehyde tested. More acceptors responded to oxygenated monoterpenes than to monoterpene hydrocarbons. β-Bisabolol, the major volatile of cotton, was the most active sesquiterpene. In general, males, which are responsible for host selection and pheromone production, were more sensitive to plant odors than were females. In fact, males were as sensitive to β-bisabolol and heptanal as to aggregation pheromone components. Electrophysiological data are discussed with regard to the role of insect and host plant volatiles in host selection and aggregation behavior of the boll weevil.

  4. [Assessment of a risk from exposure to atmosphere bus industrial emissions].

    Stepkin, Iu I; Kuzmichev, M K

    2009-01-01

    The carcinogenic and noncarcinogenic risks to health were estimated in accordance with the requirements stated in the guide P 2.1.10.1920-04 "Guidelines for assessing the health risk in the population exposed to the chemicals polluting the environment" (approved by G. G. Onishchenko, state sanitary inspector on March 5, 2004) and comprised four successive steps: 1) identification of a hazard; 2) estimation of a dose-response relationship; 3) evaluation of exposure of the population to chemical substances; 4) characterization of a risk, by calculating the individual carcinogenic risk, hazard coefficients and indices characterizing the noncarcinogenic risk. The performed assessment of the health risk to the population living in the area exposed to the ambient air pollutant emissions by the AOA "Shinnyi Kompleks Amtel-Chenozymye" (Amtel-Chernozem Tyre Complex) allowed determination of priority pollutants, by taking into account their effect on human health. The individual carcinogenic risk to health has been found to be higher than the acceptable (safe) level (10-4) was due to the probable exposure to a 2-heptane fraction (nefras ChS 94/99) and hexavalent chromium. The highest non-carcinogenic risk to human was also due to the heptane fraction (nefras ChS 94/99) (hazard coefficient > 1).

  5. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue.

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-06-10

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15-150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method.

  6. Binding of carbonyl flavours to canola, pea and wheat proteins using GC/MS approach.

    Wang, Kun; Arntfield, Susan D

    2014-08-15

    Interactions of homologous aldehydes (hexanal, heptanal, and octanal) and ketones (2-hexanone, 2-heptanone, and 2-octanone) to salt and alkaline-extracted canola and pea proteins and commercial wheat gluten were studied using GC/MS. Long-chain aldehyde flavours exhibited higher binding affinity, regardless of protein type and isolation method. Salt-extracted canola protein isolates (CPIs) revealed the highest binding capacity to all aldehydes followed by wheat gluten and salt-extracted pea protein isolates (PPIs), while binding of ketone flavours decreased in the order: PPIs>wheat gluten>CPIs. Two aldolisation products, 2-butyl-2-octenal and 2-pentyl-2-nonenal, were detected from the interactions between CPIs with hexanal and heptanal, respectively. Protein thermal behaviour in the presence of these compounds was analysed by differential scanning calorimeter, where decreased ΔH inferred potential conformational changes due to partial denaturation of PPIs. Compared to ketones, aldehyde flavours possessed much higher "unfolding capacity" (lower ΔH), which accounted for their higher binding affinities. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Application of saponin biosurfactant and its recovery in the MEUF process for removal of methyl violet from wastewater.

    Samal, Kulbhushan; Das, Chandan; Mohanty, Kaustubha

    2017-12-01

    The potential of saponin, a biosurfactant, in the micellar enhanced ultrafiltration (MEUF) process was tested systematically for removal of methyl violet from wastewater. For this, the aqueous extract of reetha (Sapindus mukorossi) pericarp which contains saponin was used as the biosurfactant. First, the micellar solubilization of methyl violet in saponin micelles was investigated in terms of molar solubilization power (SP) of saponin. It was observed that the adsorption of methyl violet on the agglomerates of saponin micelles was mainly responsible for the enhanced solubilization. The Gibbs free energy of solubilization (calculated as -29.63 kJ mol -1 ) suggested that process was feasible and spontaneous. The MEUF experiments were performed in batch as well as continuous mode using saponin biosurfactant, and the effect of operating parameters on permeate flux and solute retention were evaluated. The removal of methyl violet in MEUF process was >99% achieved with 10 kDa polyethersulfone (PES) membrane for feed dye concentration of 250 mg L -1 at studied conditions. Finally, the saponin in permeate was recovered using n-heptane and n-butanol by solvent extraction process. The solvent n-butanol showed better extraction efficiency as compared to n-heptane for saponin extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Liquid–liquid extraction of toluene from alkane with pyridinium based ionic liquid ([BPy][NO3] and [HPy][NO3]) at 298.15 K and atmospheric pressure

    Enayati, Mobin; Mokhtarani, Babak; Sharifi, Ali; Anvari, Sanam; Mirzaei, Mojtaba

    2016-01-01

    Highlights: • Extraction of toluene from alkane with pyridinium based ionic liquid was studied. • The ionic liquids [BPy][NO 3 ] and [HPy][NO 3 ] were used. • The effect of alkane chain length on selectivity of toluene was evaluated. • The effect of alkyl chain length of ionic liquids on toluene selectivity was investigated. • The experimental data were correlated with the NRTL model. - Abstract: The focus of this paper is to study the liquid−liquid extraction process for the separation of toluene from alkane employing the ionic liquids N-butylpyridinium nitrate, [BPy][NO 3 ], and N-hexylpyridinium nitrate, [HPy][NO 3 ], as a new solvents. New experimental data for the ternary systems of {[BPy][NO 3 ] (1) + heptane, or octane, or decane (2) + toluene (3)} and {[HPy][NO 3 ] (1) + heptane, or octane, or decane (2) + toluene (3)} at T = 298.15 K and atmospheric pressure are reported. The Othmer-Tobias and Hand correlation are examined to check the reliability of the experimental LLE data. The toluene distribution ratios and selectivity were calculated form the experimental data. The selectivity values are higher than unity which indicates the ILs, [BPy][NO 3 ] and [HPy][NO 3 ], used in this work are potential solvents to separate toluene from alkane. Besides, the effect of the alkane chain length in the selectivity values was evaluated. In addition, the result of the NRTL thermodynamic modeling shows, the experimental data were satisfactorily correlated.

  9. Excess molar volumes of the ternary system {methylcyclohexane (1)+cyclohexane (2)+n-alkanes (3)} at T=298.15 K

    Iloukhani, Hossein; Rezaei-Sameti, Mahdi

    2005-01-01

    Densities were experimentally determined in the whole range of composition at T=298.15 K for the ternary system {methylcyclohexane (1)+cyclohexane (2)+n-alkanes (3)} and for the seven corresponding binary systems. The n-alkanes include n-hexane, n-heptane, and n-octane. Excess molar volumes, V E , were calculated for the binaries and ternaries systems. The V 123 E data are positive over the entire range of composition for the systems {methylcyclohexane (1)+cyclohexane (2)+n-heptane (3) or n-octane (3)} at three fixed compositions (f m =X 1 /X 2 ). For the system {methylcyclohexane (1)+cyclohexane (2)+n-hexane (3)}, the V E values showed positive for f m =0.3 and negative for f m =3. The V E data exhibit, an inversion in sign in the mixture containing f m =1 for later ternary system. Several empirical expressions are used to predict and correlate the ternary excess molar volumes from experimental results on the constituted binaries and analyzed to gain insight about liquid mixture interactions

  10. Premixed flame chemistry of a gasoline primary reference fuel surrogate

    Selim, Hatem

    2017-03-10

    Investigating the combustion chemistry of gasoline surrogate fuels promises to improve detailed reaction mechanisms used for simulating their combustion. In this work, the combustion chemistry of one of the simplest, but most frequently used gasoline surrogates – primary reference fuel 84 (PRF 84, 84 vol% iso-octane and 16 vol% n-heptane), has been examined in a stoichiometric premixed laminar flame. Time-of-flight mass spectrometry coupled with a vacuum ultraviolet (VUV) synchrotron light source for species photoionization was used. Reactants, major end-products, stable intermediates, free radicals, and isomeric species were detected and quantified. Numerical simulations were conducted using a detailed chemical kinetic model with the most recently available high temperature sub-mechanisms for iso-octane and heptane, built on the top of an updated pentane isomers model and AramcoMech 2.0 (C0C4) base chemistry. A detailed interpretation of the major differences between the mechanistic pathways of both fuel components is given. A comparison between the experimental and numerical results is depicted and rate of production and sensitivity analyses are shown for the species with considerable disagreement between the experimental and numerical findings.

  11. Exploring the chemical kinetics of partially oxidized intermediates by combining experiments, theory, and kinetic modeling.

    Hoyermann, Karlheinz; Mauß, Fabian; Olzmann, Matthias; Welz, Oliver; Zeuch, Thomas

    2017-07-19

    Partially oxidized intermediates play a central role in combustion and atmospheric chemistry. In this perspective, we focus on the chemical kinetics of alkoxy radicals, peroxy radicals, and Criegee intermediates, which are key species in both combustion and atmospheric environments. These reactive intermediates feature a broad spectrum of chemical diversity. Their reactivity is central to our understanding of how volatile organic compounds are degraded in the atmosphere and converted into secondary organic aerosol. Moreover, they sensitively determine ignition timing in internal combustion engines. The intention of this perspective article is to provide the reader with information about the general mechanisms of reactions initiated by addition of atomic and molecular oxygen to alkyl radicals and ozone to alkenes. We will focus on critical branching points in the subsequent reaction mechanisms and discuss them from a consistent point of view. As a first example of our integrated approach, we will show how experiment, theory, and kinetic modeling have been successfully combined in the first infrared detection of Criegee intermediates during the gas phase ozonolysis. As a second example, we will examine the ignition timing of n-heptane/air mixtures at low and intermediate temperatures. Here, we present a reduced, fuel size independent kinetic model of the complex chemistry initiated by peroxy radicals that has been successfully applied to simulate standard n-heptane combustion experiments.

  12. Advanced physical fine coal cleaning spherical agglomeration. Final report

    1990-09-01

    The project included process development, engineering, construction, and operation of a 1/3 tph proof-of-concept (POC) spherical agglomeration test module. The POC tests demonstrated that physical cleaning of ultrafine coal by agglomeration using heptane can achieve: (1) Pyritic sulfur reductions beyond that possible with conventional coal cleaning methods; (2) coal ash contents below those which can be obtained by conventional coal cleaning methods at comparable energy recoveries; (3) energy recoveries of 80 percent or greater measured against the raw coal energy content; (4) complete recovery of the heptane bridging liquid from the agglomerates; and (5) production of agglomerates with 3/8-inch size and less than 30 percent moisture. Test results met or exceeded all of the program objectives. Nominal 3/8-inch size agglomerates with less than 20 percent moisture were produced. The clean coal ash content varied between 1.5 to 5.5 percent by weight (dry basis) depending on feed coal type. Ash reductions of the run-of-mine (ROM) coal were 77 to 83 percent. ROM pyritic sulfur reductions varied from 86 to 90 percent for the three test coals, equating to total sulfur reductions of 47 to 72 percent.

  13. Possible room temperature superconductivity in conductors obtained by bringing alkanes into contact with a graphite surface

    Yasushi Kawashima

    2013-05-01

    Full Text Available Electrical resistances of conductors obtained by bringing alkanes into contact with a graphite surface have been investigated at room temperatures. Ring current in a ring-shaped container into which n-octane-soaked thin graphite flakes were compressed did not decay for 50 days at room temperature. After two HOPG plates were immersed into n-heptane and n-octane at room temperature, changes in resistances of the two samples were measured by four terminal technique. The measurement showed that the resistances of these samples decrease to less than the smallest resistance that can be measured with a high resolution digital voltmeter (0.1μV. The observation of persistent currents in the ring-shaped container suggests that the HOPG plates immersed in n-heptane and n-octane really entered zero-resistance state at room temperature. These results suggest that room temperature superconductor may be obtained by bringing alkanes into contact with a graphite surface.

  14. Optimization and scale up of trickling bed bioreactors for degradation of volatile organic substances

    Schindler, I.

    1996-01-01

    For optimization and scale up of trickling bed bioreactors used in waste gas cleaning following investigations were made: the degradation of toluene was measured in reactors with various volumes and diameter to high ratios. The degradation of toluene was investigated in bioreactors with different carrier materials. It turned out, that the increase of the elimination capacity with the height of the reactor depends on the carrier material. At low gas velocities PU-foam allows higher elimination capacities than pallrings, VSP and DINPAC. On the other hand for PU-foam there is a permanent danger of clogging. The other materials allowed a stable operation for several months. Mass transfer of toluene was studied by absorption experiments in a 100 litre plant without microorganisms. The experiments lead to a henry coefficient of 0,23 (kg/m3)g/(kg/m3)l. Mass transfer coefficients were calculated between 3,6 and 5,2 depending an the space velocity of the gas and the trickling density of the water phase. The degradation of ethyl acetate, toluene and heptane was investigated considering the different water solubility of these substances. Further on degradation of toluene and heptane in several mixtures was investigated. (author)

  15. [Identification of migrants from nitrile-butadiene rubber gloves].

    Mutsuga, Motoh; Kawamura, Yoko; Wakui, Chiseko; Maitani, Tamio

    2003-04-01

    Polyvinyl chloride gloves containing di(2-ethylhexyl) phthalate are restricted for food contact use. In their place, disposable gloves made from nitrile-butadiene rubber (NBR) are used in contact with foodstuffs. Some unknown substances were found to migrate into n-heptane from NBR gloves. By GC/MS, HR-MS and NMR, their chemical structures were confirmed to be 2,2,4-trimethyl-1,3-pentanediol diisobutyrate (used as a plasticizer), 4,4'-butylidenedi(6-tert-butyl-m-cresol), a mixture of styrenated phenols consisting of 2-(alpha-methylbenzyl)phenol, 4-(alpha-methylbenzyl)phenol, 2,6-di(alpha-methylbenzyl)phenol, 2,4-di(alpha-methylbenzyl)phenol and 2,4,6-tri(alpha-methylbenzyl)phenol (used as antioxidants), and 2,4-di-tert-butylphenol, which seems to a degradation product of antioxidant. Migration levels of these compounds were 1.68 micrograms/cm2 of 2,4-di-tert-butylphenol, 2.80 micrograms/cm2 of 2,2,4-trimethyl-1,3-pentanediol diisobutyrate, 46.08 micrograms/cm2 of styrenated phenols and 4.22 micrograms/cm2 of 4,4'-butylidenedi(6-tert-butyl-m-cresol) into n-heptane, respectively. The content of total styrenated phenols was 6,900 micrograms/g in NBR gloves.

  16. [Migrants from disposable gloves and residual acrylonitrile].

    Wakui, C; Kawamura, Y; Maitani, T

    2001-10-01

    Disposable gloves made from polyvinyl chloride with and without di(2-ethylhexyl) phthalate (PVC-DEHP, PVC-NP), polyethylene (PE), natural rubber (NR) and nitrile-butadiene rubber (NBR) were investigated with respect to evaporation residue, migrated metals, migrants and residual acrylonitrile. The evaporation residue found in n-heptane was 870-1,300 ppm from PVC-DEHP and PVC-NP, which was due to the plasticizers. Most of the PE gloves had low evaporation residue levels and migrants, except for the glove designated as antibacterial, which released copper and zinc into 4% acetic acid. For the NR and NBR gloves, the evaporation residue found in 4% acetic acid was 29-180 ppm. They also released over 10 ppm of calcium and 6 ppm of zinc into 4% acetic acid, and 1.68-8.37 ppm of zinc di-ethyldithiocarbamate and zinc di-n-butyldithiocarbamate used as vulcanization accelerators into n-heptane. The acrylonitrile content was 0.40-0.94 ppm in NBR gloves.

  17. Interference-free mid-IR laser absorption detection of methane

    Pyun, Sung Hyun; Cho, Jungwan; Davidson, David F; Hanson, Ronald K

    2011-01-01

    A novel, mid-IR scanned-wavelength laser absorption diagnostic was developed for time-resolved, interference-free, absorption measurement of methane concentration. A differential absorption (peak minus valley) scheme was used that takes advantage of the structural differences of the absorption spectrum of methane and other hydrocarbons. A peak and valley wavelength pair was selected to maximize the differential cross-section (σ peak minus valley ) of methane for the maximum signal-to-noise ratio, and to minimize that of the interfering absorbers. Methane cross-sections at the peak and valley wavelengths were measured over a range of temperatures, 1000 to 2000 K, and pressures 1.3 to 5.4 atm. The cross-sections of the interfering absorbers were assumed constant over the small wavelength interval between the methane peak and valley features. Using this diagnostic, methane concentration time histories during n-heptane pyrolysis were measured behind reflected shock waves in a shock tube. The differential absorption scheme efficiently rejected the absorption interference and successfully recovered the vapor-phase methane concentration. These measurements allowed the comparison with methane concentration time-history simulations derived from a current n-heptane reaction mechanism (Sirjean et al 2009 A high-temperature chemical kinetic model of n-alkane oxidation JetSurF version 1.0)

  18. Prediction of warmed-over flavour development in cooked chicken by colorimetric sensor array.

    Kim, Su-Yeon; Li, Jinglei; Lim, Na-Ri; Kang, Bo-Sik; Park, Hyun-Jin

    2016-11-15

    The aim of this study was to develop a simple and rapid method based on colorimetric sensor array (CSA) for evaluation of warmed-over flavour (WOF) in cooked chicken. All samples were classified according to storage time by CSA coupled with principle component analysis (PCA) or hierarchical cluster analysis (HCA). The CSA data were used to establish prediction models with thiobarbituric acid reactive substances (TBARS), pentanal, hexanal, or heptanal associated with WOF by partial least square regression (PLSR). For the TBARS model, the coefficient of determination (rp(2)) was 0.9997 in the prediction range of 0.28-0.69mg/kg. In each of the models for pentanal, hexanal, and heptanal, all rp(2) were higher than 0.960 in the range of 0.58-2.10mg/kg, 5.50-11.69mg/kg, and 0.09-0.16mg/kg, respectively. These results demonstrate that the CSA was able to predict WOF development and to distinguish between each storage time. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. On the controlling mechanism of the upper turnover states in the NTC regime

    Ji, Weiqi

    2015-12-18

    Using n-butane, n-heptane and iso-octane as representative fuels exhibiting NTC (negative temperature coefficient) behavior, comprehensive computational studies with detailed mechanisms and theoretical analysis were performed to investigate the upper stationary point, denoted as turnover states, on the NTC curve near the higher temperature regime, where the ignition delay τ exhibits a local maximum. It is found that the global behavior of the turnover states exhibits distinctive thermodynamic and kinetic characteristics under different pressures, in that the ignition delay at the turnover states shows an Arrhenius dependence on the temperature T and an approximate inverse quadratic power law dependence on the pressure P. These global behaviors imply that the temperature and pressure of the turnover states are not independent and can be correlated by Arrhenius dependence, as ln P ∝ 1/T. Further theoretical analyses demonstrate that such turnover states result from the competition between the low-temperature chain branching reactions and the decomposition of the intermediate species, and therefore correspond to a critical value, α, of the ratio of OH production from low-temperature chemistry. In addition, the ignition delay at the turnover state can be well correlated by the analytical expression derived by Peters et al., with the further demonstration that the pressure dependence of the turnover ignition delay mainly result from the H2O2 decomposition reaction. Comparison of the present results with the literature experimental data of n-heptane ignition delay time shows very good agreement.

  20. Molecular mechanism of carbon nanotube to activate Subtilisin Carlsberg in polar and non-polar organic media

    Zhang, Liyun; Li, Yuzhi; Yuan, Yuan; Jiang, Yuanyuan; Guo, Yanzhi; Li, Menglong; Pu, Xuemei

    2016-11-01

    In the work, we mainly used molecular dynamics (MD) simulation and protein structure network (PSN) to study subtilisin Carlsberg (SC) immobilized onto carbon nanotube (CNT) in water, acetonitrile and heptane solvents, in order to explore activation mechanism of enzymes in non-aqueous media. The result indicates that the affinity of SC with CNT follows the decreasing order of water > acetonitrile > heptane. The overall structure of SC and the catalytic triad display strong robustness to the change of environments, responsible for the activity retaining. However, the distances between two β-strands of substrate-binding pocket are significantly expanded by the immobilization in the increasing order of water communication paths to the substrate-binding pocket, leading to its larger change than the free-enzymes. Interestingly, the increase in the number of the pathways upon immobilization is not dependent on the absorbed extent but the desorbed one, indicating significant role of shifting process of experimental operations in influencing the functional region. In addition, some conserved and important hot-residues in the paths are identified, providing molecular information for functional modification.

  1. Photoreduction of chlorothalonil fungicide on plant leaf models.

    Monadjemi, S; El Roz, M; Richard, C; Ter Halle, A

    2011-11-15

    Photodegradation is seldom considered at the surface of vegetation after crop spraying. Chlorothalonil, a broad-spectrum foliar fungicide with a very widespread use worldwide, was considered. To represent the waxy upper layer of leaves, tests were performed within thin paraffin wax films or in n-heptane. Laser flash photolysis together with steady-state irradiation in n-heptane allowed the determination of the photodegradation mechanisms Chlorothalonil ability to produce singlet oxygen was measured; noteworthy its efficiency is close to 100%. Additionally, chlorothalonil photodegradation mainly proceeds through reductive dechlorination. In these hydrophobic media, a radical mechanism was evidenced. Photochemical tests on wax films under simulated solar light show that formulated chlorothalonil is more reactive than pure chlorothalonil. The field-extrapolated half-life of photolysis on vegetation was estimated to 5.3 days. This value was compared to the half-lives of penetration and volatilization available in the literature. It appears that chlorothalonil dissipation from crops is ruled by both photodegradation and penetration. The relative importance of the two paths probably depends on meteorological factors and on physicochemical characteristics of the crop leaf cuticle.

  2. Polymethylated [Fe(η6-arene)2]2+ dications: methyl-group rearrangements and application of the EINS mechanism.

    Štíbr, Bohumil; Bakardjiev, Mario; Hájková, Zuzana; Holub, Josef; Padělková, Zdenka; Růžička, Aleš; Kennedy, John D

    2011-06-14

    Reactions between the methylated arenes ArMe(n) [where ArMe(n) = C(6)Me(n)H((6-n)), and n = 1-6] and FeCl(2) in heptane at 90 °C in the presence of anhydrous AlCl(3) give, for the arenes with n = 1-5, extensive isomerisations and disproportionations involving the methyl groups on the arene rings, and the formation of mixtures of [Fe(ArMe(n))(2)](2+) dications that defy separation into pure species. GC-MS studies of AlCl(3)/mesitylene and AlCl(3)/durene reactions in the absence of FeCl(2) (90 °C, 2 h) allow quantitative assessments of the rearrangements, and the EINS mechanism (electrophile-induced nucleophilic substitution) is applied to rationalise the phenomena. By contrast, ArMe(n) / FeCl(2) /AlCl(3) reactions in heptane for 24-36 h at room-temperature proceed with no rearrangements, allowing the synthesis of the complete series of pure [Fe(ArMen)](2+) cations in yields of 48-71%. The pure compounds are characterised by (1)H NMR spectroscopy and electrospray-ionization mass-spectrometry (ESI-MS), and the structures of [Fe(m-xylene)(2)][PF(6)](2) and [Fe(durene)(2)][PF(6)](2) are established by single-crystal X-ray diffraction analyses.

  3. Electrostatic atomization of hydrocarbon fuels and bio-alcohols for engine applications

    Agathou, Maria S.; Kyritsis, Dimitrios C.

    2012-01-01

    Highlights: ► Butanol e-spray phenomenology and structure was studied and compared to ethanol and heptane. ► An unsteady behavior that resulted in lack of monodispersity was observed for all cases. ► Sprays emanated from oscillating menisci, which is incompatible with steady cone-jet operation. ► Droplet Weber numbers were measured to be substantial, pointing to secondary droplet break-up. ► Coulombic fission was investigated, but the droplets were charged well below the Rayleigh limit. - Abstract: Electrostatically assisted sprays of butanol were established and compared with the ones of fuels of automotive interest, namely ethanol and heptane. First, electrospray phenomenology was investigated through high-speed visualization for a variety of conditions. Then, spray structure was studied through droplet size and velocity measurements, using Phase Doppler Anemometry, for a wide range of flow rates and applied voltages. Particular emphasis was placed on the determination of the dependence of droplet size and velocity on mass flow rate and applied electric field. Visualization and measurements of droplet size and speed revealed an unstable and polydisperse electrospray behavior for most conditions. Several factors were identified as responsible for this unstable behavior and were investigated experimentally for the butanol case. These included: oscillations of e-spray menisci, droplet disruption due to Coulombic fission and secondary droplet break-up because of high Weber numbers.

  4. Adsorption of non-ionic ABC triblock copolymers: Surface modification of TiO2 suspensions in aqueous and non-aqueous medium

    Lerch, Jean-Philippe; Atanase, Leonard Ionut; Riess, Gérard

    2017-10-01

    A series of non-ionic ABC triblock copolymers, such as poly(butadiene)-b-poly(2-vinylpyrridine)-b-poly(ethylene oxide) (PB-P2VP-PEO) were synthesized by sequential anionic polymerizations. For these copolymers comprising an organo-soluble PB and a water-soluble PEO block, their P2VP middle block has been selected for its anchoring capacity on solid surfaces. The adsorption isotherms on TiO2 were obtained in heptane and in aqueous medium, as selective solvents. In both of these cases, the P2VP middle block provides the surface anchoring, whereas PB and PEO sequences are acting as stabilizing moieties in heptane and water respectively. By extension to ABC triblock copolymers of the scaling theory developed for diblock copolymers, the density of adsorbed chains could be correlated with the molecular characteristics of the PB-P2VP-PEO triblock copolymers. From a practical point a view, it could be demonstrated that these copolymers are efficient dispersing agents for the TiO2 pigments in both aqueous and non-aqueous medium.

  5. The influence of carbon and oxygen on the magnetic characteristics of press-less sintered NdFeB magnets

    Xia, M.; Abrahamsen, A.B.; Bahl, C.R.H.; Veluri, B.; Søegaard, A.I.; Bøjsøe, P.; Millot, S.

    2017-01-01

    The Pressless Process (PLP) was adopted to manufacture NdFeB sintered magnets, where the investigations on carbon and oxygen residues from heptane milling liquid media and graphite crucibles used for sintering were quantified to evaluate the influence on the magnetic characteristics. The carbon and oxygen content in the magnets produced from wet ball milling of strip cast flakes was found to be of the order 10 4 ppm and 4·10 4 ppm respectively, which resulted in soft magnetic behavior. However using jet milling the carbon and oxygen concentration were decreased by an order of magnitude resulting in coercivity of up to 829 kA/m. Thus the influence of the carbon from the graphite crucibles is small. - Highlights: • It is found that the carbon from graphite crucibles will not influence the NdFeB. • The carbon from heptane mixed with NdFeB powder will react with the NdFeB, which breaks the magnetic properties of NdFeB. • Pressless process works well with graphite crucibles, without worrying that carbon has damage on magnets.

  6. First Townsend coefficient of organic vapour in avalanche counters

    Sernicki, J.

    1990-01-01

    A new concept is presented in the paper for implementing the proven method of determining the first Townsend coefficient (α) of gases using an avalanche counter. The A and B gas constants, interrelated by the expression α/p=A exp[-B/(K/p)], are analyzed. Parallel-plate avalanche counters (PPAC) with an electrode spacing d from 0.1 to 0.4 cm have been employed for the investigation, arranged to register low-energy alpha particles at n-heptane vapour pressures of p≥5 Torr. An in-depth discussion is given, covering the veracity and the behaviour vs K/p, of the n-heptane A and B constants determined at reduced electric-field intensity values ranging from 173.5 to 940 V/cm Torr; the constants have been found to depend upon d. The results of the investigation are compared to available data of the α coefficient of organic vapours used in avalanche counters. The PPAC method of determining α reveals some imperfections at very low values of the pd product. (orig.)

  7. Two novel solvent system compositions for protected synthetic peptide purification by centrifugal partition chromatography.

    Amarouche, Nassima; Giraud, Matthieu; Forni, Luciano; Butte, Alessandro; Edwards, F; Borie, Nicolas; Renault, Jean-Hugues

    2014-04-11

    Protected synthetic peptide intermediates are often hydrophobic and not soluble in most common solvents. They are thus difficult to purify by preparative reversed-phase high-performance liquid chromatography (RP-HPLC), usually used for industrial production. It is then challenging to develop alternative chromatographic purification processes. Support-free liquid-liquid chromatographic techniques, including both hydrostatic (centrifugal partition chromatography or CPC) and hydrodynamic (counter-current chromatography or CCC) devices, are mainly involved in phytochemical studies but have also been applied to synthetic peptide purification. In this framework, two new biphasic solvent system compositions covering a wide range of polarity were developed to overcome solubility problems mentioned above. The new systems composed of heptane/tetrahydrofuran/acetonitrile/dimethylsulfoxide/water and heptane/methyl-tetrahydrofuran/N-methylpyrrolidone/water were efficiently used for the CPC purification of a 39-mer protected exenatide (Byetta®) and a 8-mer protected peptide intermediate of bivalirudin (Angiox®) synthesis. Phase compositions of the different biphasic solvent systems were determined by (1)H nuclear magnetic resonance. Physico-chemical properties including viscosity, density and interfacial tension of these biphasic systems are also described. Copyright © 2014 Elsevier B.V. All rights reserved.

  8. Investigation of Asphaltene Adsorption onto Zeolite Beta Nanoparticles to Reduce Asphaltene Deposition in a Silica Sand Pack

    Kashefi Sepideh

    2018-01-01

    Full Text Available Zeolite beta nanoparticles were used as a new asphaltene adsorbent for reducing asphaltene deposition during fluid injection into a silica sand pack. At first, the asphaltene adsorption efficiency and capacity of zeolite beta nanoparticles were determined by UV-Vis spectrophotometer. It was found that the proper concentration of nanoparticles for asphaltene adsorption was 10 g/L and the maximum asphaltene adsorption onto zeolite beta was 1.98 mg/m2. Second, two dynamic experiments including co-injection of crude oil and n-heptane (as an asphaltene precipitant with and without use of zeolite beta nanoparticles in the sand pack was carried out. The results showed that the use of zeolite beta nanoparticles increased the permeability ratio and outlet fluid's asphaltene content about 22% and 40% compared to without use of nanoparticles, respectively. Moreover, a model based on monolayer asphaltene adsorption onto nanoparticles and asphaltene deposition mechanisms including surface deposition, entrainment and pore throat plugging was developed to determine formation damage during co-injection of crude oil and n-heptane into the sand pack. The proposed model presented good prediction of permeability and porosity ratios with AAD% of 1.07 and 0.07, respectively.

  9. High pressure combustion of liquid fuels. [alcohol and n-paraffin fuels

    Canada, G. S.

    1974-01-01

    Measurements were made of the burning rates and liquid surface temperatures for a number of alcohol and n-paraffin fuels under natural and forced convection conditions. Porous spheres ranging in size from 0.64-1.9 cm O.D. were emloyed to simulate the fuel droplets. The natural convection cold gas tests considered the combustion in air of methanol, ethanol, propanol-1, n-pentane, n-heptane, and n-decane droplets at pressures up to 78 atmospheres. The pressure levels of the natural convection tests were high enough so that near critical combustion was observed for methanol and ethanol vaporization rates and liquid surface temperature measurements were made of droplets burning in a simulated combustion chamber environment. Ambient oxygen molar concentrations included 13%, 9.5% and pure evaporation. Fuels used in the forced convection atmospheric tests included those listed above for the natural convection tests. The ambient gas temperature ranged from 600 to 1500 K and the Reynolds number varied from 30 to 300. The high pressure forced convection tests employed ethanol and n-heptane as fuels over a pressure range of one to 40 atmospheres. The ambient gas temperature was 1145 K for the two combustion cases and 1255 K for the evaporation case.

  10. Oriented Structure of Pentablock Copolymers Induced by Solution Extrusion

    Harada, Tamotsu; Bates, Frank S.; Lodge, Timothy P.

    2002-03-01

    Highly oriented structure of a poly(styrene-co-butadiene) pentablock copolymer (Mw; 104,700 g/mol, weight percentage of polybutadiene blocks; 29 wt of concentrated solutions. The pentablock copolymer was dissolved into mixtures of toluene and heptane, and the polymer concentration ranged from 40 wt extrusion, the pentablock copolymer was solidified either by coagulation in methanol or by evaporation of the solvent. Interestingly, a highly oriented lamellar structure was confirmed through the small angle X-ray scattering over a specific range of heptane composition, which is a good solvent for polybutadiene, although the hexagonal cylinder morphology was identified for the melt sample. The transition from the oriented lamellar to highly oriented cylinder structure was observed by annealing the samples at temperatures above the glass transition temperature of polystyrene. Moreover, a transition from parallel to perpendicular orientation in the lamellar state was observed with an increase of the extrusion shear rate. A comparison between pentablock and triblock copolymers will be also discussed.

  11. Performance estimation of ejector cycles using heavier hydrocarbon refrigerants

    Kasperski, Jacek; Gil, Bartosz

    2014-01-01

    Computer software basing on theoretical model of Huang et al. with thermodynamic properties of hydrocarbons was prepared. Investigation was focused on nine hydrocarbons: propane, butane, iso-butane, pentane, iso-pentane, hexane, heptane and octane. A series of calculations was carried out for the generator temperature between 70 and 200 °C, with assumed temperatures of evaporation 10 °C and condensation 40 °C. Calculation results show that none of the hydrocarbons enables high efficiency of a cycle in a wide range of temperature. Each hydrocarbon has its own maximal entrainment ratio at its individual temperature of optimum. Temperatures of entrainment ratios optimum increase according to the hydrocarbon heaviness with simultaneous increase of entrainment ratio peak values. Peak values of the COP do not increase according to the hydrocarbons heaviness. The highest COP = 0.32 is achieved for iso-butane at 102 °C and the COP = 0.28 for pentane at 165 °C. Heptane and octane can be ignored. - Highlights: • Advantages of use of higher hydrocarbons as ejector refrigerants were presumed. • Computer software basing on theoretical model of Huang et al. (1999) was prepared. • Optimal temperature range of vapor generation for each hydrocarbon was calculated

  12. Group type analysis of asphalt by column liquid chromatography

    Zhang, C.; Yang, J.; Xue, Y.; Li, Y. [Chinese Academy of Science, Taiyuan (China)

    2008-07-01

    An improved analysis method for characterization of asphalt was established. The method is based on column chromatography technique. The asphalts were separated into four groups: saturates, aromatics, resins, and asphaltenes, quantitatively. About 0.1 g of sample was required in each analysis. About 20 mL of n-heptanes was used to separate out saturates first. Then about 35 mL of n-heptanes/dichloromethane (.5, v/v) mixture was used to separate out aromatics. About 30 mL of dichloromethane/tetrahydrofuran (1/3, v/v) mixture was used to separate out resin. The quality of the separation was confirmed by infrared spectra (IR) and {sup 1}H NMR analysis. The model compounds, tetracosan for saturates, dibenz(o)anthracen for aromatics, and acetanilide for resins were used for verification. The IR and {sup 1}H NMR analysis of the prepared fractions from the column liquid chromatography were in good agreement that of pure reagents.

  13. Limonene ozonolysis in the presence of nitric oxide: Gas-phase reaction products and yields

    Ham, Jason E.; Harrison, Joel C.; Jackson, Stephen R.; Wells, J. R.

    2016-05-01

    The reaction products from limonene ozonolysis were investigated using the new carbonyl derivatization agent, O-tert-butylhydroxylamine hydrochloride (TBOX). With ozone (O3) as the limiting reagent, five carbonyl compounds were detected. The yields of the carbonyl compounds are discussed with and without the presence of a hydroxyl radical (OHrad) scavenger, giving insight into the influence secondary OH radicals have on limonene ozonolysis products. The observed reaction product yields for limonaketone (LimaKet), 7-hydroxyl-6-oxo-3-(prop-1-en-2-yl)heptanal (7H6O), and 2-acetyl-5-oxohexanal (2A5O) were unchanged suggesting OHrad generated by the limonene + O3 reaction does not contribute to their formation. The molar yields of 3-isopropenyl-6-oxo-heptanal (IPOH) and 3-acetyl-6-oxoheptanal (3A6O) decreased by 68% and >95%; respectively, when OHrad was removed. This suggests that OHrad radicals significantly impact the formation of these products. Nitric oxide (NO) did not significantly affect the molar yields of limonaketone or IPOH. However, NO (20 ppb) considerably decreased the molar reaction product yields of 7H6O (62%), 2A5O (63%), and 3A6O (47%), suggesting NO reacted with peroxyl intermediates, generated during limonene ozonolysis, to form other carbonyls (not detected) or organic nitrates. These studies give insight into the transformation of limonene and its reaction products that can lead to indoor exposures.

  14. Experimental and numerical investigations on spray characteristics of fatty acid methyl esters

    Lanjekar, R. D.; Deshmukh, D.

    2018-02-01

    A comparative experimental and numerical study is conducted to establish the significance of the use of single-component over multi-component representatives of biodiesel, diesel and their blend for predicting spray tip penetration. Methyl oleate and methyl laurate are used as single-component representative fuels for biodiesel. The pure components n-heptane, n-dodecane and n-tetradecane are used as single-component representative fuels for diesel. Methyl laurate is found to represent biodiesel of coconut, whereas methyl oleate is found to represent biodiesel having high percentage of long-chain fatty acid esters. The spray tip penetration of methyl oleate is found to be in good agreement with the measured spray tip penetration of karanja biodiesel. The spray tip penetration prediction of n-heptane fuel is closely following diesel spray tip penetration along with that of n-tetradecane and n-dodecane. The study suggests that the knowledge of the single-component representatives of biodiesel, diesel and their blend is sufficient to predict the spray tip penetration of the corresponding biodiesel, diesel and their blend under non-evaporating environment.

  15. Experimental and numerical investigations on spray characteristics of fatty acid methyl esters.

    Lanjekar, R D; Deshmukh, D

    2018-02-01

    A comparative experimental and numerical study is conducted to establish the significance of the use of single-component over multi-component representatives of biodiesel, diesel and their blend for predicting spray tip penetration. Methyl oleate and methyl laurate are used as single-component representative fuels for biodiesel. The pure components n -heptane, n -dodecane and n -tetradecane are used as single-component representative fuels for diesel. Methyl laurate is found to represent biodiesel of coconut, whereas methyl oleate is found to represent biodiesel having high percentage of long-chain fatty acid esters. The spray tip penetration of methyl oleate is found to be in good agreement with the measured spray tip penetration of karanja biodiesel. The spray tip penetration prediction of n -heptane fuel is closely following diesel spray tip penetration along with that of n -tetradecane and n -dodecane. The study suggests that the knowledge of the single-component representatives of biodiesel, diesel and their blend is sufficient to predict the spray tip penetration of the corresponding biodiesel, diesel and their blend under non-evaporating environment.

  16. Photochemistry of 1 and 2-(2-methylphenyl)-1,6-heptadiene. [4a-methyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene

    Barrows, R.D.; Hornback, J.M.

    1982-01-01

    In an attempt to synthesize partially saturated phenanthrene derivatives by an intramolecular Diels-Alder reaction between a photochemically produced o-xylylene (diene) and a tethered dienophile, it was found that 1 and 2 underwent a photochemically allowed (2 + 2) cycloaddition. Irradiation of 1 gave 6-(2-methylphenyl)bicyclo(3.2.0)heptane in 86% yield. Upon irradiation of 2, a benzvalene rearrangement of 2 first took place, producing the meta isomer 2-(3-methylphenyl)-1,6-heptadiene, followed by a (2 + 2) photocycloaddition giving 1-(3-methylphenyl)bicyclo(3.2.0)heptane in 15% yield. Direct irradiation of 2-(3-methylphenyl)-1,6-heptadiene gave the same bicyclo derivative as 2 in 34% yield. Examination of the fluorescence spectra of 1 and 2 in comparison with 1-(2-methylphenyl)propene and 2-(2-methylphenyl)-1-butene, respectively, has shown that 1 may be biased toward (2 + 2) cycloaddition where 2 is not biased toward (2 + 2) photocycloization. Attempts to produce 4a-methyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene by an intramolecular Diels-Alder reaction of the o-xylylene produced by irradiation of 3 will also be described.

  17. Successful field application of novel, non-silicone antifoam chemistries for high foaming heavy oil storage tanks in northern Alberta

    Wylde, J.J. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Clariant Oil Services, Montreal, PQ (Canada)

    2008-10-15

    Heavy oil operators in northern Alberta have experienced production problems associated with foam formation in crude oil storage tanks. The foam could enter the transportation trucks and create separation problems in the process systems. Any antifoam used in the system could not contain silicone based polymers since these compounds affected the catalysts used in upgrading the crude oil and in the manufacture of asphalt. As such, there was a need to change the performance of the antifoam product. A phosphate ester and a salted amine were the previous incumbent antifoam products that did not perform well. Several chemistries were tested, including phosphate based products; ethoxylated and propoxylated esters; polyethylene glycol esters and oleates; alcohols, fatty alcohols and ethoxylated; and propoxylated alcohols. All products had to be freeze protected to -40 degrees C, which influenced the efficacy of antifoam chemicals. This paper described how laboratory testing has evolved to field wide implementation of a combined defoamer/antifoam chemistry. The laboratory tests revealed that foam induced in heavy, aged crude was very challenging and required the addition of heptane to create the foam. A potential follow-up may be to induce the foam without the addition of heptane by using a Seltzer cylinder in a semi-quantitative manner to rank performance of products against one another. The final selection of antifoam will depend on supply chain cost since the performance of the 2 blend products was essentially the same. 12 refs., 7 figs.

  18. Photochemistry of 1 and 2-(2-methylphenyl)-1,6-heptadiene

    Barrows, R.D.; Hornback, J.M.

    1982-01-01

    In an attempt to synthesize partially saturated phenanthrene derivatives by an intramolecular Diels-Alder reaction between a photochemically produced o-xylylene (diene) and a tethered dienophile, it was found that 1 and 2 underwent a photochemically allowed [2 + 2] cycloaddition. Irradiation of 1 gave 6-(2-methylphenyl)bicyclo[3.2.0]heptane in 86% yield. Upon irradiation of 2, a benzvalene rearrangement of 2 first took place, producing the meta isomer 2-(3-methylphenyl)-1,6-heptadiene, followed by a [2 + 2] photocycloaddition giving 1-(3-methylphenyl)bicyclo[3.2.0]heptane in 15% yield. Direct irradiation of 2-(3-methylphenyl)-1,6-heptadiene gave the same bicyclo derivative as 2 in 34% yield. Examination of the fluorescence spectra of 1 and 2 in comparison with 1-(2-methylphenyl)propene and 2-(2-methylphenyl)-1-butene, respectively, has shown that 1 may be biased toward [2 + 2] cycloaddition where 2 is not biased toward [2 + 2] photocycloization. Attempts to produce 4a-methyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene by an intramolecular Diels-Alder reaction of the o-xylylene produced by irradiation of 3 will also be described

  19. Ignition delay time correlation of fuel blends based on Livengood-Wu description

    Khaled, Fathi

    2017-08-17

    In this work, a universal methodology for ignition delay time (IDT) correlation of multicomponent fuel mixtures is reported. The method is applicable over wide ranges of temperatures, pressures, and equivalence ratios. n-Heptane, iso-octane, toluene, ethanol and their blends are investigated in this study because of their relevance to gasoline surrogate formulation. The proposed methodology combines benefits from the Livengood-Wu integral, the cool flame characteristics and the Arrhenius behavior of the high-temperature ignition delay time to suggest a simple and comprehensive formulation for correlating the ignition delay times of pure components and blends. The IDTs of fuel blends usually have complex dependences on temperature, pressure, equivalence ratio and composition of the blend. The Livengood-Wu integral is applied here to relate the NTC region and the cool flame phenomenon. The integral is further extended to obtain a relation between the IDTs of fuel blends and pure components. Ignition delay times calculated using the proposed methodology are in excellent agreement with those simulated using a detailed chemical kinetic model for n-heptane, iso-octane, toluene, ethanol and blends of these components. Finally, very good agreement is also observed for combustion phasing in homogeneous charge compression ignition (HCCI) predictions between simulations performed with detailed chemistry and calculations using the developed ignition delay correlation.

  20. The BUME method: a new rapid and simple chloroform-free method for total lipid extraction of animal tissue

    Löfgren, Lars; Forsberg, Gun-Britt; Ståhlman, Marcus

    2016-06-01

    In this study we present a simple and rapid method for tissue lipid extraction. Snap-frozen tissue (15-150 mg) is collected in 2 ml homogenization tubes. 500 μl BUME mixture (butanol:methanol [3:1]) is added and automated homogenization of up to 24 frozen samples at a time in less than 60 seconds is performed, followed by a 5-minute single-phase extraction. After the addition of 500 μl heptane:ethyl acetate (3:1) and 500 μl 1% acetic acid a 5-minute two-phase extraction is performed. Lipids are recovered from the upper phase by automated liquid handling using a standard 96-tip robot. A second two-phase extraction is performed using 500 μl heptane:ethyl acetate (3:1). Validation of the method showed that the extraction recoveries for the investigated lipids, which included sterols, glycerolipids, glycerophospholipids and sphingolipids were similar or better than for the Folch method. We also applied the method for lipid extraction of liver and heart and compared the lipid species profiles with profiles generated after Folch and MTBE extraction. We conclude that the BUME method is superior to the Folch method in terms of simplicity, through-put, automation, solvent consumption, economy, health and environment yet delivering lipid recoveries fully comparable to or better than the Folch method.

  1. [Interlaboratory Study on Evaporation Residue Test for Food Contact Products (Report 2)].

    Ohno, Hiroyuki; Mutsuga, Motoh; Abe, Tomoyuki; Abe, Yutaka; Amano, Homare; Ishihara, Kinuyo; Ohsaka, Ikue; Ohno, Haruka; Ohno, Yuichiro; Ozaki, Asako; Kakihara, Yoshiteru; Kobayashi, Hisashi; Sakuragi, Hiroshi; Shibata, Hiroshi; Shirono, Katsuhiro; Sekido, Haruko; Takasaka, Noriko; Takenaka, Yu; Tajima, Yoshiyasu; Tanaka, Aoi; Tanaka, Hideyuki; Nakanishi, Toru; Nomura, Chie; Haneishi, Nahoko; Hayakawa, Masato; Miura, Toshihiko; Yamaguchi, Miku; Yamada, Kyohei; Watanabe, Kazunari; Sato, Kyoko

    2018-01-01

    An interlaboratory study was performed to evaluate the equivalence between an official method and a modified method of evaporation residue test using heptane as a food-simulating solvent for oily or fatty foods, based on the Japanese Food Sanitation Law for food contact products. Twenty-three laboratories participated, and tested the evaporation residues of nine test solutions as blind duplicates. In the official method, heating for evaporation was done with a water bath. In the modified method, a hot plate was used for evaporation, and/or a vacuum concentration procedure was skipped. In most laboratories, the test solutions were heated until just prior to dryness, and then allowed to dry under residual heat. Statistical analysis revealed that there was no significant difference between the two methods. Accordingly, the modified method provides performance equal to the official method, and is available as an alternative method. Furthermore, an interlaboratory study was performed to evaluate and compare two leaching solutions (95% ethanol and isooctane) used as food-simulating solvents for oily or fatty foods in the EU. The results demonstrated that there was no significant difference between heptane and these two leaching solutions.

  2. Nickel ion removal using nanoporous poly(styrene-co divinyl benzene) copolymer

    Bagherian, Abbas; Ghorbani, Mohsen; Mirzababaei, Seyed Nima [Babol University of Technology, Babol (Iran, Islamic Republic of)

    2015-10-15

    To achieve a suitable porous structure and high mechanical strength that is extremely valuable properties in adsorbent polymeric particles, poly(styrene-co-divinylbenzene) with high amounts of cross-linker and diverse proportions of diluent agent (porogen) were synthesized according to the methodology of the suspension polymerization technique. The structural characteristics of the particles and their adsorption properties for adsorption of Nickel ions were studied. Effect of solvent type and monomeric fraction on particles morphology and porosity was discussed. The solvents including n-heptane (HEP) and acetonitrile and monomer fraction was 50% and 30% of divinylbenzene (DVB). From the results obtained, we decided to apply an adsorbent with high mechanical strength and a porous structure appropriate for absorbing the Ni(II). The copolymer was characterized by Fourier transform infrared (FT-IR) analysis. We used scanning electron microscopy (SEM) and transmission electron microscopy (TEM) tests to study the morphology and particle size of the nanoparticles. According to the results, the copolymers synthesized with n-heptane have more porosity. Also an increase in the percentage of DVB caused finer pores. After synthesis of copolymer the applicability of these polymer beads to separation and concentration of Ni(II) is discussed. In separation of Ni(II) from aqueous solution, the effects of pH, temperature and time are discussed and thermodynamic and kinetic calculations are done and its isotherm are fitted with various equations.

  3. Changes in hydrocarbon groups, soil ecotoxicity and microbiology along horizontal and vertical contamination gradients in an old landfarming field for oil refinery waste

    Mikkonen, Anu; Hakala, Kati P.; Lappi, Kaisa; Kondo, Elina; Vaalama, Anu; Suominen, Leena

    2012-01-01

    Horizontal and vertical contaminant gradients in an old landfarming field for oil refinery waste were characterised with the aim to assess parallel changes in hydrocarbon groups and general, microbiological and ecotoxicological soil characteristics. In the surface soil polar compounds were the most prevalent fraction of heptane-extractable hydrocarbons, superseding GC–FID-resolvable and high-molar-mass aliphatics and aromatics, but there was no indication of their relatively higher mobility or toxicity. The size of the polar fraction correlated poorly with soil physical, chemical and microbiological properties, which were better explained by the total heptane-extractable and total petroleum hydrocarbons (TPH). Deleterious effects on soil microbiology in situ were observed at surprisingly low TPH concentrations (0.3%). Due to the accumulation of polar and complexed degradation products, TPH seems an insufficient measure to assess the quality and monitor the remediation of soil with weathered hydrocarbon contamination. - Highlights: ► Weathered hydrocarbon contamination and soil quality on landfarm site were studied. ► Silica fractionation of hydrocarbons separated aliphatics, aromatics and polars. ► Polar hydrocarbon metabolites had accumulated in the surface soil. ► Total hydrocarbons and TPH correlated with soil quality changes better than polars. ► Toxic response of soil microbial biomass and activity were seen at low TPH (<0.5%). - Polar metabolites constitute the largest fraction of crude oil-derived contaminants in a landfarming site, but TPH better explains soil microbial and ecotoxicological responses.

  4. Aromatization of n-octane over Pd/C catalysts

    Yin, Mengchen; Natelson, Robert H.; Campos, Andrew A.; Kolar, Praveen; Roberts, William L.

    2013-01-01

    Gas-phase aromatization of n-octane was investigated using Pd/C catalyst. The objectives were to: (1) determine the effects of temperature (400-600 °C), weight hourly space velocity (WHSV) (0.8-∞), and hydrogen to hydrocarbon molar ratio (MR) (0-6) on conversion, selectivity, and yield (2) compare the activity of Pd/C with Pt/C and Pt/KL catalysts and (3) test the suitability of Pd/C for aromatization of different alkanes including n-hexane, n-heptane, and n-octane. Pd/C exhibited the best aromatization performance, including 54.4% conversion and 31.5% aromatics yield at 500 °C, WHSV = 2 h-1, and a MR of 2. The Pd/C catalyst had higher selectivity towards the preferred aromatics including ethylbenzene and xylenes, whereas Pt/KL had higher selectivity towards benzene and toluene. The results were somewhat consistent with adsorbed n-octane cyclization proceeding mainly through the six-membered ring closure mechanism. In addition, Pd/C was also capable of catalyzing aromatization of n-hexane and n-heptane. © 2012 Elsevier Ltd. All rights reserved.

  5. A LIF-PIV investigation of turbulence induced by sprays

    van der Voort, Dennis; Dam, Nico; van de Water, Willem; Clercx, Herman

    2017-11-01

    During the breakup of a high-speed liquid jet, it drags along and mixes the air surrounding it, creating turbulence. This turbulence can, in turn, influence the dispersion of the droplets in the resulting spray. Very little is known about the small-scale characteristics of the ambient turbulent flow. This work investigated spray-induced turbulence using (gas-phase) laser-induced fluorescent tracer particle image velocimetry (LIF-PIV), which suppresses the strong light scattering of jet and droplets on the images. The results for both a heptane (h) and water (w) spray (135 m/s and 125 m/s respectively) show that the heptane spray generates stronger turbulence due to the difference in breakup between the two fluids. Using a large-eddy estimation, carefully compensating for the finite size of the PIV windows, the dissipation rate ɛ and the small-scale turbulence characteristics are estimated as ɛh = 190 +/-25 m2s-3, ɛw = 120 +/-30 m2s-3, Reλ,h = 380 +/-40, Reλ,w = 290 +/-40, ηh = 65 +/-3 μm, and ηw = 75 +/-5 μm. We will discuss the influence of the turbulent fluctuations in the surrounding air on the dispersion of droplets. This work is part of the research programme of the Foundation for Fundamental Research on Matter (FOM), which is part of the Dutch Organisation for Scientific Research (NWO).

  6. An experimental and numerical analysis of the influence of the inlet temperature, equivalence ratio and compression ratio on the HCCI auto-ignition process of Primary Reference Fuels in an engine

    Machrafi, Hatim [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert (France); Cavadiasa, Simeon [UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert (France)

    2008-11-15

    In order to understand better the auto-ignition process in an HCCI engine, the influence of some important parameters on the auto-ignition is investigated. The inlet temperature, the equivalence ratio and the compression ratio were varied and their influence on the pressure, the heat release and the ignition delays were measured. The inlet temperature was changed from 25 to 70 C and the equivalence ratio from 0.18 to 0.41, while the compression ratio varied from 6 to 13.5. The fuels that were investigated were PRF40 and n-heptane. These three parameters appeared to decrease the ignition delays, with the inlet temperature having the least influence and the compression ratio the most. A previously experimentally validated reduced surrogate mechanism, for mixtures of n-heptane, iso-octane and toluene, has been used to explain observations of the auto-ignition process. The same kinetic mechanism is used to better understand the underlying chemical and physical phenomena that make the influence of a certain parameter change according to the operating conditions. This can be useful for the control of the auto-ignition process in an HCCI engine. (author)

  7. An experimental and numerical analysis of the HCCI auto-ignition process of primary reference fuels, toluene reference fuels and diesel fuel in an engine, varying the engine parameters

    Machrafi, Hatim; Cavadias, Simeon [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France); UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France); Gilbert, Philippe [UPMC Universite Paris 06, Institut Jean Le Rond D' Alembert, 2, place de la Gare de Ceinture, 78210 St Cyr-I' Ecole (France)

    2008-11-15

    For a future HCCI engine to operate under conditions that adhere to environmental restrictions, reducing fuel consumption and maintaining or increasing at the same time the engine efficiency, the choice of the fuel is crucial. For this purpose, this paper presents an auto-ignition investigation concerning the primary reference fuels, toluene reference fuels and diesel fuel, in order to study the effect of linear alkanes, branched alkanes and aromatics on the auto-ignition. The auto-ignition of these fuels has been studied at inlet temperatures from 25 to 120 C, at equivalence ratios from 0.18 to 0.53 and at compression ratios from 6 to 13.5, in order to extend the range of investigation and to assess the usability of these parameters to control the auto-ignition. It appeared that both iso-octane and toluene delayed the ignition with respect to n-heptane, while toluene has the strongest effect. This means that aromatics have higher inhibiting effects than branched alkanes. In an increasing order, the inlet temperature, equivalence ratio and compression ratio had a promoting effect on the ignition delays. A previously experimentally validated reduced surrogate mechanism, for mixtures of n-heptane, iso-octane and toluene, has been used to explain observations of the auto-ignition process. (author)

  8. The development and experimental validation of a reduced ternary kinetic mechanism for the auto-ignition at HCCI conditions, proposing a global reaction path for ternary gasoline surrogates

    Machrafi, Hatim; Cavadias, Simeon; Amouroux, Jacques [UPMC Universite Paris 06, LGPPTS, Ecole Nationale Superieure de Chimie de Paris, 11, rue de Pierre et Marie Curie, 75005 Paris (France)

    2009-02-15

    To acquire a high amount of information of the behaviour of the Homogeneous Charge Compression Ignition (HCCI) auto-ignition process, a reduced surrogate mechanism has been composed out of reduced n-heptane, iso-octane and toluene mechanisms, containing 62 reactions and 49 species. This mechanism has been validated numerically in a 0D HCCI engine code against more detailed mechanisms (inlet temperature varying from 290 to 500 K, the equivalence ratio from 0.2 to 0.7 and the compression ratio from 8 to 18) and experimentally against experimental shock tube and rapid compression machine data from the literature at pressures between 9 and 55 bar and temperatures between 700 and 1400 K for several fuels: the pure compounds n-heptane, iso-octane and toluene as well as binary and ternary mixtures of these compounds. For this validation, stoichiometric mixtures and mixtures with an equivalence ratio of 0.5 are used. The experimental validation is extended by comparing the surrogate mechanism to experimental data from an HCCI engine. A global reaction pathway is proposed for the auto-ignition of a surrogate gasoline, using the surrogate mechanism, in order to show the interactions that the three compounds can have with one another during the auto-ignition of a ternary mixture. (author)

  9. The influence of carbon and oxygen on the magnetic characteristics of press-less sintered NdFeB magnets

    Xia, M., E-mail: maxi@dtu.dk [Department of Energy Conversion and Storage, DTU Risø Campus, Technical University of Denmark, Roskilde (Denmark); Abrahamsen, A.B. [Department of Wind Energy, DTU Risø campus, Technical University of Denmark, Roskilde (Denmark); Bahl, C.R.H. [Department of Energy Conversion and Storage, DTU Risø Campus, Technical University of Denmark, Roskilde (Denmark); Veluri, B.; Søegaard, A.I. [Grundfos A/S, DK-8850 Bjerringbro (Denmark); Bøjsøe, P. [Holm Magnetics APS, 2800 Kongens Lyngby (Denmark); Millot, S. [FJ Industries A/S, 5863 Ferritslev (Denmark)

    2017-01-15

    The Pressless Process (PLP) was adopted to manufacture NdFeB sintered magnets, where the investigations on carbon and oxygen residues from heptane milling liquid media and graphite crucibles used for sintering were quantified to evaluate the influence on the magnetic characteristics. The carbon and oxygen content in the magnets produced from wet ball milling of strip cast flakes was found to be of the order 10{sup 4} ppm and 4·10{sup 4} ppm respectively, which resulted in soft magnetic behavior. However using jet milling the carbon and oxygen concentration were decreased by an order of magnitude resulting in coercivity of up to 829 kA/m. Thus the influence of the carbon from the graphite crucibles is small. - Highlights: • It is found that the carbon from graphite crucibles will not influence the NdFeB. • The carbon from heptane mixed with NdFeB powder will react with the NdFeB, which breaks the magnetic properties of NdFeB. • Pressless process works well with graphite crucibles, without worrying that carbon has damage on magnets.

  10. Measurement of critical temperatures and critical pressures for binary mixtures of methyl tert-butyl ether (MTBE) + alcohol and MTBE + alkane

    Han, Kewei; Xia, Shuqian; Ma, Peisheng; Yan, Fangyou; Liu, Tao

    2013-01-01

    Highlights: • The critical properties of seven binary mixtures related to gasoline were measured. • The critical properties of the five systems containing MTBE were reported for the first time. • Binary interaction parameters were fitted by experimental data using PR EOS with Wong–Sandler mixing rule. • Redlich–Kister equation was used to correlate the experimental data. -- Abstract: A set of high-pressure view apparatus was designed for determining the critical properties of chemicals. In order to check the reliability of the apparatus, the critical temperatures (T c ) and critical pressures (P c ) of pure n-heptane, cyclohexane, methanol, ethanol, 1-propanol, methyl tert-butyl ether (MTBE), and binary mixture n-hexane + ethanol were measured. The experimental data were in good agreement with the literature data, which proves the reliability of the apparatus used in the work. The critical temperatures and critical pressures of five binary mixtures containing gasoline additive (MTBE + n-heptane, MTBE + cyclohexane, MTBE + methanol, MTBE + ethanol, MTBE + 1-propanol) were measured using the high-pressure view cell with visual observation. The critical temperatures and critical pressures for the five binary mixtures were all reported for the first time. In addition, the critical temperatures and critical pressures of the binary mixture n-heptane + cyclohexane (two of main components in gasoline) were also measured. All the critical lines for the mixtures studied are continuous which connect the critical points of the two pure components, indicating their phase diagrams belong to type I proposed by Scott and van Konynenburg. The critical points of these systems were calculated by the Peng–Robinson equation of state with the Wong–Sandler mixing rule. This model could calculate the critical properties of the mixtures well with the binary interaction parameter k ij obtained by fitting the experimental critical data. And the experimental data were all

  11. Stability studies of colloidal silica dispersions in binary solvent mixtures

    Bean, Keith Howard

    1997-01-01

    A series of monodispersed colloidal silica dispersions, of varying radii, has been prepared. These particles are hydrophilic in nature due to the presence of surface silanol groups. Some of the particles have been rendered hydrophobic by terminally grafting n-alkyl (C 18 ) chains to the surface. The stability of dispersions of these various particles has been studied in binary mixtures of liquids, namely (i) ethanol and cyclohexane, and (ii) benzene and n-heptane. The ethanol - cyclohexane systems have been studied using a variety of techniques. Adsorption excess isotherms have been established and electrophoretic mobility measurements have been made. The predicted stability of the dispersions from D.V.L.O. calculations is compared to the observed stability. The hydrophilic silica particles behave as predicted by the calculations, with the zeta potential decreasing and the van der Waals attraction increasing with increasing cyclohexane concentration. The hydrophobic particles behave differently than expected, and the stability as a function of solvent mixture composition does not show a uniform trend. The effect of varying the coverage of C 18 chains on the surface and the effect of trace water in the systems has also been investigated. Organophilic silica dispersions in benzene - n-heptane solvent mixtures show weak aggregation and phase separation into a diffuse 'gas-like' phase and a more concentrated 'liquid-like' phase, analogous to molecular condensation processes. Calculations of the van der Waals potential as a function of solvent mixture composition show good agreement with the observed stability. Determination of the number of particles in each phase at equilibrium allows the energy of flocculation to be determined using a simple thermodynamic relationship. Finally, the addition of an AB block copolymer to organophilic silica particles in benzene n-heptane solvent mixtures has been shown to have a marked effect on the dispersion stability. This stability

  12. Fabrication of electrocatalytic Ta nanoparticles by reactive sputtering and ion soft landing

    Johnson, Grant E.; Moser, Trevor; Engelhard, Mark; Browning, Nigel D.; Laskin, Julia

    2016-11-07

    About 40 years ago, it was shown that tungsten carbide exhibits similar catalytic behavior to Pt for certain commercially relevant reactions, thereby suggesting the possibility of cheaper and earth-abundant substitutes for costly and rare precious metal catalysts. In this work, reactive magnetron sputtering of Ta in the presence of three model hydrocarbons (2-butanol, heptane, and m-xylene) combined with gas aggregation and ion soft landing was employed to prepare organic-inorganic hybrid nanoparticles (NPs) on surfaces for evaluation of catalytic activity and durability. The electro-catalytic behavior of the NPs supported on glassy carbon was evaluated in acidic aqueous solution by cyclic voltammetry. The Ta-heptane and Ta-xylene NPs were revealed to be active and robust toward promotion of the oxygen reduction reaction, an important process occurring at the cathode in fuel cells. In comparison, pure Ta and Ta-butanol NPs were essentially unreactive. Characterization techniques including atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) were applied to probe how different sputtering conditions such as the flow rates of gases, sputtering current, and aggregation length affect the properties of the NPs. AFM images reveal the focused size of the NPs as well as their preferential binding along the step edges of graphite surfaces. In comparison, TEM images of the same NPs on carbon grids show that they bind randomly to the surface with some agglomeration but little coalescence. The TEM images also reveal morphologies with crystalline cores surrounded by amorphous regions for NPs formed in the presence of 2-butanol and heptane. In contrast, NPs formed in the presence of m-xylene are amorphous throughout. XPS spectra indicate that while the percentage of Ta, C, and O in the NPs varies depending on the sputtering conditions and hydrocarbon employed, the electron binding energies of the elements are similar

  13. Simulation of circularly polarized luminescence spectra using coupled cluster theory

    McAlexander, Harley R.; Crawford, T. Daniel, E-mail: crawdad@vt.edu [Department of Chemistry, Virginia Tech, Blacksburg, Virginia 24061 (United States)

    2015-04-21

    We report the first computations of circularly polarized luminescence (CPL) rotatory strengths at the equation-of-motion coupled cluster singles and doubles (EOM-CCSD) level of theory. Using a test set of eight chiral ketones, we compare both dipole and rotatory strengths for absorption (electronic circular dichroism) and emission to the results from time-dependent density-functional theory (TD-DFT) and available experimental data for both valence and Rydberg transitions. For two of the compounds, we obtained optimized geometries of the lowest several excited states using both EOM-CCSD and TD-DFT and determined that structures and EOM-CCSD transition properties obtained with each structure were sufficiently similar that TD-DFT optimizations were acceptable for the remaining test cases. Agreement between EOM-CCSD and the Becke three-parameter exchange function and Lee-Yang-Parr correlation functional (B3LYP) corrected using the Coulomb attenuating method (CAM-B3LYP) is typically good for most of the transitions, though agreement with the uncorrected B3LYP functional is significantly worse for all reported properties. The choice of length vs. velocity representation of the electric dipole operator has little impact on the EOM-CCSD transition strengths for nearly all of the states we examined. For a pair of closely related β, γ-enones, (1R)-7-methylenebicyclo[2.2.1]heptan-2-one and (1S)-2-methylenebicyclo[2.2.1]heptan-7-one, we find that EOM-CCSD and CAM-B3LYP agree with the energetic ordering of the two possible excited-state conformations, resulting in good agreement with experimental rotatory strengths in both absorption and emission, whereas B3LYP yields a qualitatively incorrect result for the CPL signal of (1S)-2-methylenebicyclo[2.2.1]heptan-7-one. Finally, we predict that one of the compounds considered here, trans-bicyclo[3.3.0]octane-3,7-dione, is unique in that it exhibits an achiral ground state and a chiral first excited state, leading to a strong CPL

  14. The combined effect of food-simulating solutions, brushing and staining on color stability of composite resins

    Silva, Tânia Mara Da; Sales, Ana Luísa Leme Simões; Pucci, Cesar Rogerio; Borges, Alessandra Bühler; Torres, Carlos Rocha Gomes

    2017-01-01

    Abstract Objective: This study evaluated the effect of food-simulating media associated with brushing and coffee staining on color stability of different composite resins. Materials and methods: Eighty specimens were prepared for each composite: Grandio SO (Voco), Amaris (Voco), Filtek Z350XT (3M/ESPE), Filtek P90 (3M/ESPE). They were divided into four groups according to food-simulating media for 7 days: artificial saliva (control), heptane, citric acid and ethanol. The composite surface was submitted to 10,950 brushing cycles (200 g load) in an automatic toothbrushing machine. The specimens were darkened with coffee solution at 37 °C for 24 h. After each treatment, color measurements were assessed by spectrophotometry, using CIE L*a*b* system. The overall color change (ΔE) was determined for each specimen at baseline (C1) and after the treatments (food-simulating media immersion/C2, brushing/C3 and dye solution/C4). Data were analyzed by two-way repeated measures ANOVA and Tukey’s tests (p composites (p = .001), time (p = .001) and chemical degradation (p = .002). The mean of ΔE for composites were: Z350XT (5.39)a, Amaris (3.89)b, Grandio (3.75)bc, P90 (3.36)c. According to food-simulating media: heptane (4.41)a, citric acid (4.24)a, ethanol (4.02)ab, artificial saliva (3.76)b. For the treatments: dye solution (4.53)a, brushing (4.26)a, after food-simulating media (3.52)b. Conclusions: The composite resin Filtek Z350XT showed significantly higher staining than all other composite resin tested. The immersion in heptane and citric acid produced the highest color alteration than other food-simulating media. The exposure of samples to brushing protocols and darkening in coffee solution resulted in significant color alteration of the composite resins. PMID:28642926

  15. Modified bitumen for embedding of radioactive wastes

    Bozkurt, C.

    1984-11-01

    This work describes new possibilities of using polymer modified bitumen as matrix material for embedding of low- and medium level radioactive wastes. Epoxy resins, polyurethane resins and styrene-butadiene-copolymers with 20-40 weight per cent are used as modifying agents. Penetration and softening point (ring and ball) of modified samples have been measured. Further the resistance to toluene and leaching rate in n-heptane have been determined. Within these polymer bitumen combinations investigated, the epoxy resins having a high epoxid equivalent weight with dicarbooxylic acid anhydrid hardeners and tertiary amin accelerators give the most dense network, highest thermodimensional stability and lowest leaching rate in organic solvents. 71 refs., 9 figs., 6 tabs

  16. A comprehensive detailed kinetic mechanism for the simulation of transportation fuels

    Mehl, Marco; Zhang, Kuiwen; Wagnon, Scott; Kukkadapu, Goutham; Westbrook, Charles K.; Pitz, William J.; Zhang, Yinjia; Curran, Henry J.; Al Rachidi, Mariam; Atef, Nour; Sarathy, Mani; Ahmed, Ahfaz

    2017-01-01

    This work presents a recently compiled comprehensive model for transportations fuels resulting from the collaboration of three research groups: LLNL, NUI Galway and KAUST. In the past 5 years new fundamental calculations led to significant improvements in the fidelity of detailed kinetic models of important surrogate components (e.g. n-heptane, iso-octane, toluene…) improving predictions of the combustion behavior of pure components and mixtures. By extending the newly adopted reaction rate rules, mechanisms for components that were not included in the previous LLNL gasoline and diesel surrogate mechanisms were developed (e.g. polyalkylated aromatics, cycloalkanes, components from bio-logical sources…). The major features of this updated and extended model are presented together with validation comparisons, examples of applications and future directions.

  17. Pollutant emissions from gasoline combustion. 1. Dependence on fuel structural functionalities.

    Zhang, Hongzhi R; Eddings, Eric G; Sarofim, Adel F

    2008-08-01

    To study the formation of air pollutants and soot precursors (e.g., acetylene, 1,3-butadiene, benzene, and higher aromatics) from aliphatic and aromatic fractions of gasoline fuels, the Utah Surrogate Mechanisms is extended to include submechanisms of gasoline surrogate compounds using a set of mechanism generation techniques. The mechanism yields very good predictions of species concentrations in premixed flames of n-heptane, isooctane, benzene, cyclohexane, olefins, oxygenates, and gasoline using a 23-component surrogate formulation. The 1,3-butadiene emission comes mainly from minor fuel fractions of olefins and cyclohexane. The benzene formation potential of gasoline components shows the following trends as functions of (i) chemical class: n-paraffins produced by the real fuel should have priority when selecting candidate surrogate components for combustion simulations.

  18. Technical note: Characterization of key volatile odorants in rabbit meat using gas chromatography mass spectrometry with simultaneous distillation extraction

    Y.J. Xie

    2016-12-01

    Full Text Available This study explored the key volatile compounds in both male and female rabbit meat. Simultaneous distillation extraction with dichloromethane was adopted to extract the volatile compounds in Hyla rabbit meat. A total of 35 volatile compounds were identified by gas chromatography–mass spectrometry and quantified with 2, 4, 6-thimethylpyridine as internal standard. Seventeen volatile aldehydes, 4 alcohols, 2 ketones, 2 acids, 1 heterocyclic compound, 2 alkanes and 7 esters were detected. Hexanal, heptanal, octanal, nonanal, (E, E-2, 4-decadienal, 1-octen-3-ol and (Z-2-decenal were the key odorant compounds, with high relative odour activity value. Furthermore, the concentration of volatile compounds in male rabbit meat was higher than that in female rabbit meat.

  19. Investigation of A-3 adsorbent-ditolylmethane two-phase system

    Ermakov, V.A.; Benderskaya, O.S.

    1988-01-01

    Compatibility of A-3 adsorbent, produced on the basis of palygoskite clay, with organic coolant of nuclear reactors-ditolylmethane (DTM)- and the possibility to use the given adsorbent for DTM purification from surfactant impurities are investigated. Compatibility of the adsorbent with DTM was evaluated by the concentration of its constituents in liquid phase. Sufactant adsorption was observed by the change in acid number of coolant, optical density at λ=396 nm and adsorbate mass in the adsorbent. From spent adsorbent the coolant was washed out by n-heptane, and the adsorbate - by methylene chloride, othanol and water in succession. On the basis of the results obtained the conclusion is made that A3 possesses a high chemical stability in DTM medium, i.e. it is compatible with DTM and can be used for its purification from surfactant impurities sorbed on heat-transferring surface

  20. Concentration of ions Co(II), Ni(II) at the Tokem-250 carboxylic cation exchange for catalysts development

    Zharkova, Valentina; Bobkova, Ludmila; Brichkov, Anton; Kozik, Vladimir

    2017-11-01

    Sorption and catalytic properties of the cation exchanger are investigated. It was found that the Tokem-250 has a wide operating range of pH. The value of the effective ionization constant of the functional groups of the cation exchanger (pKa) is 6.59. The Tokem-250 cation exchanger exhibits selectivity to Ni2+ ions to Co2+ (D˜103). This is probably due to the stability of ion-exchange complexes detected by the method of diffuse reflectance electron spectroscopy (ESDD). According to these data, for Co2+ ions, in contrast to Ni2+, tetragonal distortion of octahedral coordination is characteristic, which has a positive effect on the stability of complexes with Co2+. To obtain spherical catalysts on the basis of Tokem-250, cobalt-containing samples of cation exchanger were used. The developed spherical materials have catalytic activity in the reactions of deep and partial oxidation of n-heptane.

  1. Morphology and magnetic properties of CeCo5 submicron flakes prepared by surfactant-assisted high-energy ball milling

    Zhang, J. J.; Gao, H. M.; Yan, Y.; Bai, X.; Su, F.; Wang, W. Q.; Du, X. B.

    2012-10-01

    CeCo5 permanent magnetic alloy has been processed by surfactant assisted high energy ball milling. Heptane and oleic acid were used as the solvent and surfactant, respectively. The amount of surfactant used was 50% by weight of the starting powder. The produced particles were deposited on a piece of copper (4 mm in length and width) under a magnetic field of 27 kOe applied along the copper surface and immobilized by ethyl α-cyanoacrylate. Scanning electron microscope pictures show that the particles are flakes, several μm in length and width and tens of nm in thickness. X-ray diffraction patterns and magnetic measurements prove that the flakes are crystalline with c-axes magnetic anisotropy. The easy magnetization axis is oriented perpendicular to the surface of the flake. A maximum coercivity of 3.3 kOe was obtained for the sample milled for 40 min.

  2. Development of a low temperature phase change material package. [for spacecraft thermal control

    Brennan, P. J.; Suelau, H. J.; Mcintosh, R.

    1977-01-01

    Test data obtained for a low temperature phase change material (PCM) canisters are presented. The canister was designed to provide up to 30 w-hrs of storage capacity at approximately -90 C with an overall thermal conductance which is greater than 8 w/deg C. N-heptane which is an n-paraffin and has a -90.6 C freezing point was used as the working fluid. The canister was fabricated from aluminum and has an aluminum honeycomb core. Its void volume permits service temperatures up to 70 C. Results obtained from component and system's tests indicate well defined melting and freezing points which are repeatable and within 1 C of each other. Subcooling effects are less than 0.5 C and are essentially negligible. Measured storage capacities are within 94 to 88% the theoretical.

  3. Surrogate fuel formulation for light naphtha combustion in advanced combustion engines

    Ahmed, Ahfaz

    2015-03-30

    Crude oil once recovered is further separated in to several distinct fractions to produce a range of energy and chemical products. One of the less processed fractions is light naphtha (LN), hence they are more economical to produce than their gasoline and diesel counterparts. Recent efforts have demonstrated usage of LN as transportation fuel for internal combustion engines with slight modifications. In this study, a multicomponent surrogate fuel has been developed for light naphtha fuel using a multi-variable nonlinear constrained optimization scheme. The surrogate, consisting of palette species n-pentane, 2-methylhexane, 2-methylbutane, n-heptane and toluene, was validated against the LN using ignition quality tester following ASTM D6890 methodology. Comparison of LN and the surrogate fuel demonstrated satisfactory agreement.

  4. Preparation and characterization of polyethylene glycol diacrylate microgels using electron beam radiation

    Hamzah, Mohd Yusof [Makmal Nanoteknologi, Bahagian Teknologi Sinaran (Malaysia); Isa, Naurah Mat; Napia, Liyana M. Ali [ALURTRON, Bahagian Kemudahan Iradiasi, Malaysian Nuclear Agency, 43000, Kajang, Selangor (Malaysia)

    2014-02-12

    The use of microemulsion in the development of nanosized gels based on polyethylene glycol diacrylate (PEGDA) is demonstrated. PEGDA was solubilized in n-heptane with use of sodium docusate (AOT) at 0.15M concentration to form reverse micelles. These micelles were than irradiated at 5, 10, 15, 20 and 25 kGy using electron beam (EB) to crosslink the entrapped polymer in the micelles. Ionizing radiation was imparted to the emulsions to generate crosslinking reaction in the micelles formed. The nanosized gels were evaluated in terms of particle diameter using dynamic light scattering (DLS) and the images of the nanosized gels were studied using transmission electron microscopy (TEM). Results show that the size and shape of the particles are influenced by concentration of PEGDA and radiation dose. This study showed that this method can be utilized to produce nanosized gels.

  5. A novel antibacterial and antifungal phenolic compound from the endophytic fungus Pestalotiopsis mangiferae.

    Subban, Kamalraj; Subramani, Ramesh; Johnpaul, Muthumary

    2013-01-01

    A novel phenolic compound, 4-(2,4,7-trioxa-bicyclo[4.1.0]heptan-3-yl) phenol (1), was isolated from Pestalotiopsis mangiferae, an endophytic fungus associated with Mangifera indica Linn. The structure of the compound was elucidated on the basis of comprehensive spectral analysis (UV, IR, ¹H-, ¹³C- and 2D-NMR, as well as HRESI-MS). Compound (1) shows potent antibacterial and antifungal activity against Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli, Micrococcus luteus, Pseudomonas aeruginosa and Candida albicans. The transmission electron microscope study for the mode of inhibition of compound (1) on bacterial pathogens revealed the destruction of bacterial cells by cytoplasm agglutination with the formation of pores in cell wall membranes.

  6. Emission factors from road traffic from a tunnel study (Gubrist tunnel, Switzerland). Part 1 Concept and first results

    Staehelin, Johannes; Brunner, Dominik; Baumle, Martin [Atmospheric Science, ETH-Hoenggerberg, Zuerich (Switzerland); Schlapfer, Kurt [Carbotech AG, Basel (Switzerland); Burgin, Toni; Meier, Markus [Amt fuer Technische Anlagen und Lufthygiene Kanton Zuerich ATAL, Zuerich (Switzerland); Steinemann, Urs [Ingenieurbuero Steinemann, Wollerau (Switzerland); Schneider, Stefan; Zahner, Christoph; Keiser, Stephan [Planungsbuero Jud AG, Zuerich (Switzerland); Stahel, Werner; Keller, Christian [Sem. for Statistics, ETH-Z, Zuerich (Switzerland)

    1995-06-22

    In the industrialized world a large part of the emission of the primary air pollutants (NO{sub x}, volatile organic compounds (VOC) and CO) originates from road traffic. Here we present the concept and first results of a tunnel study which took place from September 20th to September 26th, 1993, at the Gubrist tunnel (close to Zuerich, Switzerland) in which the emission factors of a large number of individual VOCs, total hydrocarbons (t-HC), CO, NO{sub x} and SO{sub 2} are determined. The first tentative results of the emission factors of NO{sub x}, CO, t-HC and 26 individual hydrocarbons (alkanes and aromatics in the volatility range from n-heptane to n-decane) for the average of all vehicles and the light duty vehicles at an average speed of 90 km/h are given

  7. High-performance liquid chromatographic method for guanylhydrazone compounds.

    Cerami, C; Zhang, X; Ulrich, P; Bianchi, M; Tracey, K J; Berger, B J

    1996-01-12

    A high-performance liquid chromatographic method has been developed for a series of aromatic guanylhydrazones that have demonstrated therapeutic potential as anti-inflammatory agents. The compounds were separated using octadecyl or diisopropyloctyl reversed-phase columns, with an acetonitrile gradient in water containing heptane sulfonate, tetramethylammonium chloride, and phosphoric acid. The method was used to reliably quantify levels of analyte as low as 785 ng/ml, and the detector response was linear to at least 50 micrograms/ml using a 100 microliters injection volume. The assay system was used to determine the basic pharmacokinetics of a lead compound, CNI-1493, from serum concentrations following a single intravenous injection in rats.

  8. The gas phase structure of α -pinene, a main biogenic volatile organic compound

    Neeman, Elias M.; Avilés Moreno, Juan Ramón; Huet, Thérèse R.

    2017-12-01

    The gas phase structure of the bicyclic atmospheric aerosol precursor α-pinene was investigated employing a combination of quantum chemical calculation and Fourier transform microwave spectroscopy coupled to a supersonic jet expansion. The very weak rotational spectra of the parent species and all singly substituted 13C in natural abundance have been identified, from 2 to 20 GHz, and fitted to Watson's Hamiltonian model. The rotational constants were used together with geometrical parameters from density functional theory and ab initio calculations to determine the rs, r0, and rm(1 ) structures of the skeleton, without any structural assumption in the fit concerning the heavy atoms. The double C=C bond was found to belong to a quasiplanar skeleton structure containing 6 carbon atoms. Comparison with solid phase structure is reported. The significant differences of α-pinene in gas phase and other gas phase bicyclic monoterpene structures (β-pinene, nopinone, myrtenal, and bicyclo[3.1.1]heptane) are discussed.

  9. [Chemical hazards when working with solvent glues].

    Domański, Wojciech; Makles, Zbigniew

    2012-01-01

    Solvent glues are used in a wide variety of industries, e.g., textile, footwear and rubber. The problem of workers' exposure to solvent vapors is rarely tackled within the area of occupational safety and health in small and medium-sized enterprises. In order to assess exposure to solvents, organic solvents emitted by glues were identified in the samples of workplace air. The concentration of acetone, benzene, cyclohexane, ethylbenzene, n-hexane, methylcyclohexane, butyl acetate and toluene were determined. The obtained results evidenced the presence of cyclohexane, ethylbenzene, ethylcyclohexane, heptane, n-hexane, o-xylene, methylcyclohexane, methylcyclopentane, butyl acetate and toluene in workplace air. The concentration of those compounds in workplace air was low, usually below 0.15 of MAC. At some workstations the presence of benzene was also observed. Occupational risk was assessed at workstations where gluing took place. It showed that the risk at those workstations was medium or low.

  10. Verification of key odorants in rose oil by gas chromatography-olfactometry/aroma extract dilution analysis, odour activity value and aroma recombination.

    Xiao, Zuobing; Li, Jing; Niu, Yunwei; Liu, Qiang; Liu, Junhua

    2017-10-01

    Rose oil is much too expensive but very popular. It's well known that the flower oil's aroma profile hasn't been intensively investigated. In order to verify the aroma profile of rose oil, the synthetic blend of odorants was prepared and then compared with the original rose oil using electronic nose analysis (ENA) combined with quantitative descriptive analysis (QDA). The odorants from rose oils were screened out by Gas Chromatography-Olfactometry/aroma extract dilution analysis (GC-O/AEDA) combined with odour activity value (OAV). Both ENA and QDA indicated the recombination model derived from OAV and GC-O/AEDA closely resembled the original rose oil. The experiment results show that rose oxide, linalool, α-pinene, β-pinene, nonanal, heptanal citronellal, phenyl ethyl alcohol, benzyl alcohol, eugenol, methyl eugenol, β-citronellol, hexyl acetate, β-ionone, nerol, etc. are very important constituent to rose oil aroma profile.

  11. Natural and synthetic oviposition stimulants forCatolaccus grandis (Burks) females.

    Guerra, A A; Martinez, S; Sonia Del Rio, H

    1994-07-01

    Oviposition behavior was elicited fromCatolaccus grandis (Burks) (Hymenoptera: Pteromalidae) females, an ectoparasitoid of the boll weevil,Anthonomus grandis Boheman (Coleoptera: Curculionidae), by smears of freshly cut cotton bolls or smears of extracts prepared with boll weevil damaged or undamaged cotton boll tissues. Oviposition behavior was also elicited fromC. grandis females by smears made withn-pentane,n-hexane,n-heptane, and isooctane. This is the first report of oviposition behavior elicited for any parasitoid by these short-chain saturated hydrocarbons (alkanes), introducing a new concept on the chemical mediation of parasitoid behavior during host selection. Oviposition behavior was also elicited fromC. grandis females by volatiles emanating from an artificial diet devoid of insect components that was specifically developed for the in vitro rearing of ectoparasitoids. The possible use of a synergistic combination ofn-hexane and diet to optimize the mechanized production of noncontaminated eggs is also discussed.

  12. HPTLC determination of diosgenin in fenugreek seeds

    Król-Kogus Barbara

    2018-03-01

    Full Text Available A new HPTLC-densitometric method for diosgenin determination in fenugreek seeds was established after optimization of the conditions for efficient saponin extraction and acid hydrolysis. Several procedures were tested, the best of which was a three-step Soxhlet extraction, followed by hydrolysis of the obtained methanolic extract with 2 mol L-1 H2SO4. Best diosgenin separation from other hydrolysis products was obtained on HPTLC Si60F254 plates u sing a mixture of n-heptane/ethyl acetate (7:3, V/V and modified anisaldehyde as a spraying reagent. The method was preliminarily validated and the determined amounts of diosgenin in fenugreek seeds of Polish and African origin were found to be similar and ranged from 0.12-0.18 %.

  13. Further studies on the filtration of liquids using Kapton nuclear track micro filters

    Guo, S.L.; Ganz, M.; Fuest, M.; Vater, P.; Brandt, R.

    1990-01-01

    The flow rate of some liquids (water, heptane, toluene, xylene, dodecane) through Kapton nuclear track filters has been measured. The results can be interpreted with a modified Poiseuille formula. The influence of the viscosity of the liquids on their throughput through Kapton nuclear track filters has been determined. The purification of liquids with Kapton filters has been investigated. It is possible to measure the density of solid particles in deionized water by using Kapton filters. Consequently, nuclear track filters can remove solid particles from high-purity liquids. The soaking effect of some common liquid chemicals on Kapton filters has also been studied, no such soaking could be observed in most of the cases. Finally, these Kapton nuclear track filters are compared with a filter device from Hamamatsu (Japan). (orig.) [de

  14. Analysis of volatiles in silver carp by headspace solid phase micro-extraction coupled with GC-MS

    Yang Yuping; Xiong Guangquan; Cheng Wei; Liao Tao; Lin Ruotai; Geng Shengrong; Li Xin; Li Xiaoding; Wu Wenjin

    2010-01-01

    In this paper, a method for the determination of volatiles using headspace solid phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS) was presented. The extraction conditions were optimized with reference to these volatiles as hexanal, heptanal, benzaldehyde, 1-Octen-3-ol, octanal, nonanal, decenal, 2,4-heptadienal and 2,4-decadienal. The extraction of fish muscle followed by incubation on a StableFlex divinyl benzene/Carboxen/polydimethylsiloxane (DVB/CAR/PDMS) fiber during 50 in at 60 obtained the most effective extraction of the analytes. The methods by HS-SPME and GC-MS were effective in detecting volatiles in the gills, scales, viscera and fish muscles. The types of volatiles in the gill were more than other organs and the number of odors compounds was 63, and the number of volatiles in scales, viscera and fish muscles was 48, 44 and 42 respectively. (authors)

  15. Separation of benzene from alkanes by solvent extraction with 1-ethylpyridinium ethylsulfate ionic liquid

    Gomez, Elena; Dominguez, Irene; Calvar, Noelia; Dominguez, Angeles

    2010-01-01

    The (liquid + liquid) equilibrium (LLE) data for ternary mixtures {alkane + benzene + 1-ethylpyridinium ethylsulfate ([EPy][EtSO 4 ])} at T = (283.15 and 298.15) K and atmospheric pressure are presented. The alkanes used were hexane and heptane. The cloud point method was used to determinate the binodal curve, and the tie-line compositions were obtained by density measurements. The LLE data obtained were used to calculate distribution coefficients and selectivity values. The consistency of tie-line data was ascertained by applying the Othmer-Tobias and Hand equations. Correlation of the experimental tie-lines was conducted through the use of NRTL equation, which provides good correlation of the experimental data. The results show that [EPy][EtSO 4 ] can be used as an alternative solvent in liquid extraction processes for the removal of benzene from its mixtures with alkanes.

  16. Thermo-oxidation in Arauco and Arbequina Extra-virgin Olive Oil. Changes in Odour using and Electronic Nose and SPME-GC-FID

    Valeria Messina

    2010-06-01

    Full Text Available Changes in odour of Arauco and Arbequina extra-virgin olive oil were monitored during frying by electronic nose and solid-phase microextraction–gas chromatography methodologies. Electronic nose data and volatile compounds were analyzed at intervals of 60 min (t60 during 180 min of frying (t180. Principal components analysis applied to electronic nose data showed one component, PC1 which accounted 96.3 % of the total odour variation. SnO2 sensors had a positive correlation with PC1. Arauco variety corresponding to frying t120 and t180 had the highest positive correlation with PC1. Analysis of variance results for volatile compounds showed an increase on production for: 3-methyl butanal, n-pentanal, n-hexanal, n-heptanal and n-nonanal at 60 min of frying for both varieties.

  17. Fluoro-norchloroepibatidine: Preclinical assessment of acute toxicity

    Molina, Patricia E.; Ding Yushin; Carroll, F. Ivy; Liang, F.; Volkow, Nora D.; Pappas, Naomi; Kuhar, Michael; Abumrad, Naji; Gatley, S. John; Fowler, Joanna S.

    1997-01-01

    18 Fluoro-norchloroepibatidine (exo-2-(6-fluoro-3-pyridyl)-7-azabicyclo-[2.2.1]heptane [NFEP]), a labeled derivative of epibatidine, has shown promise for imaging brain nicotinic acetylcholine receptors with PET. We determined the dose-dependent effects of NFEP in conscious rats. NFEP (1.5 μg/kg; administered intravenously) resulted in 30% mortality. Neither 0.5 μg/kg or 0.25 μg/kg NFEP resulted in any significant changes in cardiorespiratory parameters, but plasma catecholamines increased (2- to 3-fold). Further studies are needed to determine the safety of NFEP that are specifically designed to assess the catecholamine response. Our results suggest that it is not advisable to initiate human PET studies with [ 18 F]-NFEP without further evidence supporting its safety

  18. Knock investigation by flame and radical species detection in spark ignition engine for different fuels

    Merola, Simona S.; Vaglieco, Bianca M.

    2007-01-01

    The present paper aims to evaluate the phenomena of normal combustion and knocking in a single cylinder, ported fuel injection, four-stroke spark-ignition engine with a four-valve production head. All the measurements were realized in an optically accessible engine equipped with a wide quartz window in the bottom of the chamber. The study was carried out using optical techniques based on flame natural emission imaging and spectroscopy from UV to visible. Radical species such as OH and HCO were detected and correlated to the onset and the duration of knock and presence of hot-spots in end-gas. Measurements were carried out at 1000 rpm with wide-open throttle and stoichiometric mixture. Pure iso-octane, suitable mixtures of iso-octane and n-heptane and commercial gasoline were used

  19. Measurements and thermodynamics of hydrotreater product sludge stability

    Andersen, S.I. [Technical Univ. of Denmark, Lyngby (Denmark)

    2003-07-01

    Sludge is a by-product of the hydrotreating process of asphaltene during feedstock conversions. The stability of the asphaltenes in the system is related to the produced sludge. The remaining asphaltenes are unstable due to chemical changes in the mixture even though a large conversion of heptane asphaltene occurs. The flocculation titration technique was applied to several feedstocks and catalysts to understand changes in stability and to develop conversion schemes that avoid sludge formation. The effect of temperature conversion was studied in detail. Results obtained by flocculation titration were in agreement with size exclusion chromatography, elemental analysis, infrared spectroscopy and other methods. The authors also examined the chemical changes in product and in product asphaltenes. It was concluded that high hydrotreatment temperature leads to the formation of unstable products as cracking occurs. It was shown that molecular weight of asphaltenes decreases during the hydroprocessing, and the transition temperature is related to the feed. tabs., figs.

  20. Investigation the performance of 0-D and 3-d combustion simulation softwares for modelling HCCI engine with high air excess ratios

    Gökhan Coşkun

    2017-10-01

    Full Text Available In this study, performance of zero and three dimensional simulations codes that used for simulate a homogenous charge compression ignition (HCCI engine fueled with Primary Reference Fuel PRF (85% iso-octane and 15% n-heptane were investigated. 0-D code, called as SRM Suite (Stochastic Reactor Model which can simulate engine combustion by using stochastic reactor model technique were used. Ansys-Fluent which can simulate computational fluid dynamics (CFD was used for 3-D engine combustion simulations. Simulations were evaluated for both commercial codes in terms of combustion, heat transfer and emissions in a HCCI engine. Chemical kinetic mechanisms which developed by Tsurushima including 33 species and 38 reactions for surrogate PRF fuel were used for combustion simulations. Analysis showed that both codes have advantages over each other.

  1. Quantifying liquid boundary and vapor distributions in a fuel spray by rainbow schlieren deflectometry.

    Taber Wanstall, C; Agrawal, Ajay K; Bittle, Joshua A

    2017-10-20

    The rainbow schlieren deflectometry (RSD) technique is used to determine the liquid boundary and the fuel volume fraction distributions in the vapor region of a high-pressure fuel spray. Experiments were conducted in a constant pressure flow vessel, whereby a customized single-hole common-rail diesel injector is used to introduce n-heptane fuel into a coflow of low-speed ambient air at two different test conditions. Only the quasi-steady period of the fuel spray is considered, and multiple injections are performed to acquire statistically significant data at an image acquisition rate of 20 kHz. An algorithm to identify the liquid boundary using intensity recorded by the RSD images is presented. The results are compared against measurements obtained by the Mie scattering technique. Results demonstrate that the RSD can be a powerful optical diagnostics technique to simultaneously quantify both the vapor and liquid regions in the high-pressure fuel sprays.

  2. Nucleophilic addition of nitriles to secondary terpene alcohols

    Kozlov, N.G.; Popova, L.A.; Nesterov, G.V.

    1987-01-01

    The addition of nitriles of varying nucleophilicity to isocamphanol and exo-1,5,5-trimethyl-bicyclo[2.2.1]heptan-2-ol (isofenchol) was investigated. The authors examined the effect of the reaction conditions on the yield and structure of the target products of the reaction: N-substituted amides. As a result of the study, it was shown that in the reaction with chloroacetonitrile, propionitrile, methoxypropionitrile, isovaleronitrile, and phenylacetonitrile under the conditions of the Ritter reaction, isocamphanol is transformed into the corresponding substituted exo-N-acyl-1,7,7-trimethylbicyclo[2.2.1]hept-2-ylamines, as in the reaction with aceto- and benzonitriles, due to 2,6-hydride displacement accompanied by Wagner-Meerwein rearrangement. The structures of these amides were demonstrated by PMR spectroscopy

  3. Biodegradation waste of the stations service by Rhodococcus erythropolis ohp-al-gp

    Pucci, Oscar Hector; Acuna, Adrian Javier; Pucci, Graciela Natalia

    2013-01-01

    The strain Rhodococcus erythropolis ohp-al-gp was isolated from turbine oil contaminated soil from northern Santa Cruz province, Argentina. Because of its potential in bioremediation, the aim was to know the abilities for degradation of pure compounds and mixtures of hydrocarbons, as well as degradation in the presence and absence of diesel nitrogen measured by gas chromatography. The strain possesses the ability to use diesel, kerosene, lubricating oil, pristane, hexane, heptane, octane, pentadecane and hexadecane. R. erythropolis ohp-al-gp has excellent potential for bioremediation of hydrocarbons, which are conflictive as lubricating oils, their potential use in removing mud from washing engines or gas stations would be its most important application. The degradation rate in optimal culture conditions, gives it an additional advantage. It also has a low degradation in the absence of nitrogen, a frequent limiting factor in Patagonian soils.

  4. Chain length dependence of the critical density of organic homologous series

    Kontogeorgis, Georgios M.; Fredenslund, Aage; Tassios, Dimitrios P.

    1995-01-01

    Whether the critical density of organic compounds belonging to a certain homologous series increases or decreases with (increasing) molecular weight has been a challenging question over the years. Two sets of experimental data have recently appeared in the literature for the critical density of n......-alkanes: Steele's data (up to n-decane) suggest that critical density increases with carbon number and reaches a limiting value. On the other hand, the data of Teja et al., 1990 which cover a broader range of n-alkanes (up to n-octadecane), reveal a decreasing trend of the critical density after a maximum at n......-heptane. Teja et al. have also presented critical density measurements for 1-alkenes (up to 1-decene) and 1-alkanols (up to 1-undecanol). These data follow the same decreasing trend with the molecular weight as n-alkanes. This trend is not in agreement with the predictions of most group-contribution methods...

  5. Modelling of Combustion and Pollutant Formation in a Large, Two-Stroke Marine Diesel Engine using Integrated CFD-Skeletal Chemical Mechanism

    Pang, Kar Mun; Karvounis, Nikolas; Schramm, Jesper

    In this reported work, simulation studies of in-cylinder diesel combustion and pollutant formation processesin a two-stroke, low-speed uniflow-scavenged marine diesel engine are presented. Numerical computation is performed by integrating chemical kinetics into CFD computations. In order...... to minimize the computational runtime, an in-house skeletal n-heptane chemical mechanism is coupled with the CFD model. This surrogate fuel model comprises 89 reactions with 32 species essential to diesel ignition/combustion processes as well as the formation of soot precursors and nitrogen monoxide (NO......). Prior to the marine engine simulation,coupling of the newly developed surrogate fuel model and a revised multi-step soot model [1] is validated on the basis of optical diagnostics measurement obtained at varying ambient pressure levels [2]. It is demonstrated that the variation of ignition delay times...

  6. Influence of clay type on the performance of Ziegler-Natta catalyst for the synthesis of nanocomposites of PE and PP

    Almeida, Lidiane A.; Marques, Maria F.V.; Oliveira, Jaqueline S.

    2011-01-01

    Polymer nanocomposites present highly improved general properties in comparison with original polymer and their conventional composites. The mayor disadvantage in preparing these materials is the difficulty in the dispersion of the nanofillers in the polymer matrix. In the present work, the synthesis of bisupported (MgCl 2 /clay) catalyst was performed for obtaining polyethylene and polypropylene nanocomposites by in situ polymerization with the aim to achieve higher dispersion of the nanofillers in the polyolefin matrix. Moreover, the influence of ammonium salt (employed in the organophilization of the clay) on the fixation of the catalyst components and therefore, on the catalyst activity was evaluated. The catalysts were characterized by TGA, SEM, EDX, and XRD. Polymers were characterized by DSC, isotactic index through heptane extractables (HS), TGA, EDX, XRD, and optical microscopy (OM). The results showed that the type of clay modifier has a great influence on the catalyst performance. (author)

  7. Total internal reflection second-harmonic generation: probing the alkane water interface

    Conboy, J.C.; Daschbach, J.L.; Richmond, G.L.

    1994-01-01

    Total internal reflection Second-Harmonic Generation (SHG) has been used to study a series of neat n-alkane/water interfaces. Polarization and incident angular-dependent measurements of the SH response show good agreement with theoretical predictions. Analysis of the incident and polarization angular-dependent SH response allows for determination of the nonlinear optical properties of molecules comprising the interfacial region. Based on Kleinman symmetry, the measured surface nonlinear susceptibilities suggest a high degree of interfacial order for octane and decane with less order indicated by the odd carbon n-alkanes examined, heptane and nonane. The SH response in reflection and transmission has been measured under a Total Internal Reflection (TIR) of the fundamental. The measured nonlinear susceptibilities in each case are found to be identical. (orig.)

  8. Experimental measurements and prediction of liquid densities for n-alkane mixtures

    Ramos-Estrada, Mariana; Iglesias-Silva, Gustavo A.; Hall, Kenneth R.

    2006-01-01

    We present experimental liquid densities for n-pentane, n-hexane and n-heptane and their binary mixtures from (273.15 to 363.15) K over the entire composition range (for the mixtures) at atmospheric pressure. A vibrating tube densimeter produces the experimental densities. Also, we present a generalized correlation to predict the liquid densities of n-alkanes and their mixtures. We have combined the principle of congruence with the Tait equation to obtain an equation that uses as variables: temperature, pressure and the equivalent carbon number of the mixture. Also, we present a generalized correlation for the atmospheric liquid densities of n-alkanes. The average absolute percentage deviation of this equation from the literature experimental density values is 0.26%. The Tait equation has an average percentage deviation of 0.15% from experimental density measurements

  9. Noncatalytic Direct Liquefaction of Biorefinery Lignin by Ethanol

    Nielsen, Joachim Bachmann; Jensen, Anders; Madsen, Line Riis

    2017-01-01

    There is a growing interest in lignin valorization to biofuels and chemicals. Here, we propose a novel and simple noncatalytic process to directly liquefy lignin rich solid residual from second generation bioethanol production by solvolysis with ethanol. Through an extensive parameter study...... in batch autoclaves assessing the effects of varying reaction temperature, reaction time, and solvent:lignin ratio, it is shown that hydrothermally pretreated enzymatic hydrolysis lignin solvolysis in supercritical ethanol can produce a heptane soluble bio-oil without the need for exhaustive deoxygenation....... The process does not require addition of catalyst or a reducing agent such as hydrogen. The process is advantageously carried out with a low reaction period ((ethanol:lignin (w/w) ratio of 2:1) which is a previously unexplored domain for lignin...

  10. Determination of solute organic concentration in contaminated soils using a chemical-equilibrium soil column system

    Gamst, Jesper; Kjeldsen, Peter; Christensen, Thomas Højlund

    2007-01-01

    using two soils with different content of organic carbon (f(oc) of 1.5 and 6.5%, respectively). A quadruple blind test of the ER-V system using glass beads in stead of soil showed an acceptable recovery (65-85%) of all of the 11 VOCs tested. Only for the most volatile compound (heptane, K-H similar...... to 80) an unacceptable recovery was found (9%). The contact time needed for obtaining chemical equilibrium was tested in the ER-H system by performing five test with different duration (1, 2, 4, 7 and 19 days) using the low organic carbon soil. Seven days of contact time appeared sufficient...... for determination of solute concentration in a contaminated soil were developed; (1) a chemical Equilibrium and Recirculation column test for Volatile organic chemicals (ER-V) and (2) a chemical Equilibrium and Recirculation column test for Hydrophobic organic chemicals (ER-H). The two test systems were evaluated...

  11. Synthesis of SERS active Au nanowires in different noncoordinating solvents

    Hou Xiaomiao; Zhang Xiaoling, E-mail: zhangxl@bit.edu.cn [Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Department of Chemistry, School of Science (China); Fang Yan, E-mail: fangyan@mail.cnu.edu.cn [Beijing Key Laboratory for Nano-Photonics and Nano-Structure (NPNS), Capital Normal University (China); Chen Shutang; Li Na; Zhou Qi [Key Laboratory of Cluster Science of Ministry of Education, Beijing Institute of Technology, Department of Chemistry, School of Science (China)

    2011-06-15

    Au nanowires with length up to micrometers were synthesized through a simple and one-pot solution growth method. HAuCl{sub 4} was reduced in a micellar structure formed by 1-octadecylamine and oleic acid in hexane, heptane, toluene and chloroform, respectively. As the non-polarity of noncoordinating solvents can affect the nucleation and growth rates of Au nanostructures, Au nanowires with different diameters could be obtained by changing the noncoordinating solvents in the synthetic process. The influences of the solvents on the morphology of Au nanowires were systematically studied. When using hexane as reaction solvent, the product turned to be high portion of Au nanowires with more uniform size than the others. Furthermore, surface-enhanced Raman scattering (SERS) spectrum of 2-thionaphthol was obtained on the Au nanowire-modified substrate, indicating that the as-synthesized Au nanowires have potential for highly sensitive optical detection application.

  12. Image Charge Effects in the Wetting Behavior of Alkanes on Water with Accounting for Water Solubility

    Kirill A. Emelyanenko

    2016-03-01

    Full Text Available Different types of surface forces, acting in the films of pentane, hexane, and heptane on water are discussed. It is shown that an important contribution to the surface forces originates from the solubility of water in alkanes. The equations for the distribution of electric potential inside the film are derived within the Debye-Hückel approximation, taking into account the polarization of the film boundaries by discrete charges at water-alkane interface and by the dipoles of water molecules dissolved in the film. On the basis of above equations we estimate the image charge contribution to the surface forces, excess free energy, isotherms of water adsorption in alkane film, and the total isotherms of disjoining pressure in alkane film. The results indicate the essential influence of water/alkane interface charging on the disjoining pressure in alkane films, and the wettability of water surface by different alkanes is discussed.

  13. Determination of basicity of neutral organic phosphorus extractants in nonpolar solvents by the 31P NMR method

    Yakshin, V.V.; Meshcheryakov, N.M.; Il'in, E.G.; Ignatov, M.E.; Laskorin, B.N.

    1984-01-01

    The variant of the NMR method application is developed for quantitative description of acidic-basic properties of neutral organic phosphorus extractants, R 3 P--O (NPE), in non-polar organic solvents. For the NPE basicity determination the dependence of the chemical shift value in NMR 31 P spectra of 0.1 M NPE solutions in the dodecane on sulfuric acid acitivity in aqueous phase at 0-12 M acidity is studied. The linear equation relating NPE basicity and electronic structure of these compounds expressed through the sum: of Kabachnik reaction constants is derived. Linear dependences between the NPE basicity value in dodecane and NPE basicity in nitromethane as well as enthalpies of complexes formation with charge transport with standard acid-iodine in heptane, enthalpies of hydrogen complexes formation with phenol and water have been found

  14. The influence of carbon and oxygen on the magnetic characteristics of press-less sintered NdFeB magnets

    Xia, M.; Abrahamsen, A. B.; Bahl, C. R. H.; Veluri, B.; Søegaard, A. I.; Bøjsøe, P.; Millot, S.

    2017-01-01

    The Pressless Process (PLP) was adopted to manufacture NdFeB sintered magnets, where the investigations on carbon and oxygen residues from heptane milling liquid media and graphite crucibles used for sintering were quantified to evaluate the influence on the magnetic characteristics. The carbon and oxygen content in the magnets produced from wet ball milling of strip cast flakes was found to be of the order 104 ppm and 4·104 ppm respectively, which resulted in soft magnetic behavior. However using jet milling the carbon and oxygen concentration were decreased by an order of magnitude resulting in coercivity of up to 829 kA/m. Thus the influence of the carbon from the graphite crucibles is small.

  15. Kinetic analysis of batch ethanol acetylation in isothermal non-stationary multiphase systems by lyophilized mycelium of Aspergillus oryzae

    Emilio Palazzi

    2011-03-01

    Full Text Available A relatively complex network of reactions has been investigated, using as a network model the isothermal batch esterification of acetic acid with ethanol in n-heptane catalyzed by lyophilized mycelium of Aspergillus oryzae. The kinetic analysis was firstly carried out on the whole system, without any simplification, by means of the well-known integral method. Owing to the poor results obtained by this way, we developed an alternative approach, combining initial rates and integral analysis and reducing the number of empirical parameters to be determined by the use of equilibrium data. All the values of the parameters calculated according to this "composite" approach to kinetic analysis well correlate with experimental data.

  16. RECOVERY OF CARBOXYLIC ACIDS FROM AQUEOUS SOLUTIONS BY LIQUID-LIQUID EXTRACTION WITH A TRIISOOCTYLAMINE DILUENT SYSTEM

    G. Malmary

    2001-12-01

    Full Text Available Tertiary alkylamines in solution with organic diluents are attractive extractants for the recovery of carboxylic acids from dilute aqueous phases. The aim of this study was to investigate the mechanism for extraction of organic acids from water by a long-chain aliphatic tertiary amine. In order to attain this objective, we studied the liquid-liquid equilibria between the triisooctylamine + 1-octanol + n-heptane system as solvent and an aqueous solution of an individual carboxylic acid such as citric, lactic and malic acids. The experiments showed that the partition coefficient for a particular organic acid depends on the kind of solute, notably when the acid concentration in the aqueous phase is low. A mathematical model, where both chemical association and physical distribution are taken into consideration, is proposed. The model suggests that the various complexes obtained between amine and organic acids contribute to the distribution of the solute between the coexisting phases in equilibrium.

  17. Study of asphaltene precipitation by Calorimetry

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David

    2007-01-01

    Can calorimetry bring new input to the Current understanding of asphaltene precipitation? In this work, two types of precipitation were studied by means of calorimetry: addition of n-heptane into asphaltene solutions and temperature/pressure variations on a recombined live oil. The first series...... of experiments showed that weak forces determine precipitation. Indeed, isothermal titration calorimetry could not detect any clear signal although this technique can detect low-energy transitions such as liquid-liquid equilibrium and rnicellization. The second series of tests proved that precipitation caused...... by T and P variations is exothermic for this system. Furthermore, the temperature-induced precipitation is accompanied by an increase in the apparent thermal expansivity. Therefore, it seems that these two phase transitions exhibit different calorimetric behaviours and they may not be as similar...

  18. The influence of petroleum asphaltenic sub fractions on the demulsifiers performance; Influencia de subfracoes asfaltenicas de petroleo sobre a acao de desemulsificantes

    Honse, Siller O.; Mansur, Claudia R.E.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas. Lab. de Macromoleculas e Coloides na Industria de Petroleo], e-mail: celias@ima.ufrj.br

    2011-07-01

    The aim of this work is to evaluate the influence of asphaltene fractions and subfractions on the stabilization of petroleum emulsions, as well as on the efficiency of demulsifiers based on poly(ethylene oxide-b-propylene oxide) (PEO-PPO). Asphaltenes were extracted from an asphaltic residue using n-heptane (C5 asphaltenes) and n-decane (asphaltenes C10). Intermediate subfractions were also obtained. Model emulsions, consisted of water and dispersions of the asphaltene in toluene were prepared, with and without adding demulsifier. The stability of the emulsions was higher when adding more polar fractions. However, asphaltenes presenting a broad distribution of polarity cause higher emulsion stability than that presenting very narrow distribution of intermediate polarity. The efficiency of PEO-PPO copolymer on emulsions separation is related to the original stability of the emulsions. In this work, it was confirmed that branched surfactant presents higher efficiency than the linear. (author)

  19. EVALUATION OF EMISSION OF CO, NO AND NOX IN EXHAUST OF DIESEL ENGINE FUELED WITH FUEL ADDITIVED

    Gilson Rodrigo de Miranda

    2011-01-01

    Full Text Available Air pollution has emerged as major global problems. In the last decade, the development of new engines, the use of different forms of treatment of exhaust gases and the increase in fuel quality were used to reduce pollutants (regulated or not. Among the various developments to reduce emissions, the use of oxygenated additives to diesel and paraffin is a quick and effective measure to reduce pollutants. In this work we studied the influence of oxygenated compounds (diethyl ether (DEE, 1-dodecanol (DOD, 2-methoxy-acetate (MEA and terc-butanol (TERC and paraffin (heptane (HEPT and n- hexadecane (CET added to diesel in order to improve the quality of CO, NO and NOx in the exhaust of diesel engine, single cylinder. The fuels used in the studies are formulations of diesel reference, here named S10, which contains low sulfur (

  20. Drag of evaporating or condensing droplets in low Reynolds number flow

    Dukowicz, J.K.

    1984-01-01

    The steady-state drag of evaporating or condensing droplets in low Reynolds number flow is computed. Droplet drag in air is obtained for five representative liquids (water, methanol, benzene, heptane, octane) for a range of ambient temperatures, pressures, and vapor concentrations. The drag is in general increased for a condensing droplet, and decreased for an evaporating droplet. The changes in drag can be quite large and depend in detail on the degree of evaporation or condensation, and on the individual liquid and vapor properties. The present results are used to test the existing experimentally derived correlations of Eisenklam and Yuen and Chen in the low Reynolds number regime. The Yuen and Chen correlation is found to be quite successful, but only in the case of condensation or mild evaporation. An improved correlation is suggested for evaporating droplets

  1. Synthesis of Molecularly Imprinted Polymer for Sterol Separation

    Yuangsawad Ratanaporn

    2016-01-01

    Full Text Available Molecular imprinted polymer (MIP was prepared by bulk polymerization in acetone using acrylamide as a functional monomer, ethylene glycol dimethacrylate as a crosslinker, stigmasterol as a template and benzoyl peroxide as an initiator. The obtained MIPs were characterized using a scanning electron microscope and a fourier transform infrared spectrophotometer. Performance in sterol adsorption of MIPs prepared under various conditions was investigated using a model solution of phytosterols in heptane, comparing with a nonimprinted polymer (NIP. Statistical analysis revealed that the amounts of crosslinker and template strongly affected the performance of MIP while the amount of solvent slightly affected the performance of MIP. MIP synthesized under the optimal condition had adsorption capacity of 1.28 mgsterols/gads which were 1.13 times of NIP.

  2. Crystal structure of (1S,3R,8R,10S-2,2-dichloro-10-hydroxy-3,7,7,10-tetramethyltricyclo[6.4.0.01,3]dodecan-9-one

    Ahmed Benzalim

    2016-05-01

    Full Text Available The asymmetric unit of the title compound, C16H24Cl2O2, contains two independent molecules (A and B which are built from three fused rings, viz. a seven-membered heptane ring, a six-membered cyclohexyl ring bearing a ketone and an alcohol group, and a cyclopropane ring bearing two Cl atoms. In the crystal, the two molecules are linked via two O—H...O hydrogen bonds, forming an A–B dimer with an R22(10 ring motif. The A molecules of these dimers are linked via a C—H...O hydrogen bond, forming chains propagating along the a-axis direction. Both molecules have the same absolute configuration, i.e. 1S,3R,8R,10S, which is based on the synthetic pathway and further confirmed by resonant scattering [Flack parameter = 0.03 (5].

  3. Selective hydrogenation of furfural on Ir/TiO2 catalysts

    Patricio Reyes

    2010-01-01

    Full Text Available Titania-supported Ir catalysts were used in the hydrogenation of furfural. Reactions were carried out in a stirred batch type reactor at 0.62MPa and 363K using a 0.10M solution of furfural in a 1:1 mixture n-heptane -ethanol as solvent. Catalysts containing 2 wt% of Ir were reduced in H2 flow at different temperatures in the range 473-773K. The catalysts were characterized by H2 chemisorption, TEM, TPR, TPD of NH3 and XPS. Conversion of furfural is higher at lower reduction temperatures, but leads to byproducts whereas reduction at higher temperatures shows selectivity to furfuryl alcohol close to 100%.

  4. Quasi-Dimensional Modelling and Parametric Studies of a Heavy-Duty HCCI Engine

    Sunil Kumar Pandey

    2011-01-01

    Full Text Available A quasi-dimensional modelling study is conducted for the first time for a heavy duty, diesel-fuelled, multicylinder engine operating in HCCI mode. This quasidimensional approach involves a zero-dimensional single-zone homogeneous charge compression ignition (HCCI combustion model along with a one-dimensional treatment of the intake and exhaust systems. A skeletal chemical kinetic scheme for n-heptane was used in the simulations. Exhaust gas recirculation (EGR and compression ratio (CR were the two parameters that were altered in order to deal with the challenges of combustion phasing control and operating load range extension. Results from the HCCI mode simulations show good potential when compared to conventional diesel performance with respect to important performance parameters such as peak firing pressure, specific fuel consumption, peak pressure rise, and combustion noise. This study shows that HCCI combustion mode can be employed at part load of 25% varying the EGR rates between 0 and 60%.

  5. Measurement of oxygen transfer from air into organic solvents

    Ramesh, Hemalata; Mayr, Torsten; Hobisch, Mathias

    2016-01-01

    biological reactions require the supply of oxygen, most normally from air. However, reliable on-line measurements of oxygen concentration in organic solvents (and hence oxygen transfer rates from air to the solvent) has to date proven impossible due limitations in the current analytical methods. Results...... applications). Subsequently, we measured the oxygen transfer rates from air into these organic solvents. Conclusion The measurement of oxygen transfer rates from air into organic solvents using the dynamic method was established using the solvent resistant optical sensor. The feasibility of online oxygen...... For the first time, we demonstrate on-line oxygen measurements in non-aqueous media using a novel optical sensor. The sensor was used to measure oxygen concentration in various organic solvents including toluene, THF, isooctane, DMF, heptane and hexane (which have all been shown suitable for several biological...

  6. Solvent extraction of hafnium(IV) by dinonylnaphthalene sulfonic acid from mixed aqueous-organic media

    Hala, J.; Piperkovova, H.

    1979-01-01

    The extraction of hafnium(IV) by heptane and toluene solutions of dinonylnaphthalene sulfonic acid (HD) from mixed aqueous-organic solutions has been studied. Alcohols, ketones, carboxylic acids, cyclic ethers, dimethylsulfoxide and dimethylformamide were used as the organic component of the mixed phase. Methanol, ethanol, formic acid and dioxane increased the extractability of Hf(IV) whereas other solvents showed only an antagonistic effect. The results were discussed from the point of view of the changes in micellar structure of HD, and compared with the uptake of Hf(IV) by resinous cation exchangers. The solubilization by HD of alcohols, carboxylic acids and dimethylsulfoxide was demonstrated by using the corresponding 14 C and 35 S labelled compounds. (author)

  7. Occurrence of diverse alkane hydroxylase alkB genes in indigenous oil-degrading bacteria of Baltic Sea surface water.

    Viggor, Signe; Jõesaar, Merike; Vedler, Eve; Kiiker, Riinu; Pärnpuu, Liis; Heinaru, Ain

    2015-12-30

    Formation of specific oil degrading bacterial communities in diesel fuel, crude oil, heptane and hexadecane supplemented microcosms of the Baltic Sea surface water samples was revealed. The 475 sequences from constructed alkane hydroxylase alkB gene clone libraries were grouped into 30 OPFs. The two largest groups were most similar to Pedobacter sp. (245 from 475) and Limnobacter sp. (112 from 475) alkB gene sequences. From 56 alkane-degrading bacterial strains 41 belonged to the Pseudomonas spp. and 8 to the Rhodococcus spp. having redundant alkB genes. Together 68 alkB gene sequences were identified. These genes grouped into 20 OPFs, half of them being specific only to the isolated strains. Altogether 543 diverse alkB genes were characterized in the brackish Baltic Sea water; some of them representing novel lineages having very low sequence identities with corresponding genes of the reference strains. Copyright © 2015 Elsevier Ltd. All rights reserved.

  8. Role of low density lipoprotein in the activation of plasma lysolecithin acyltransferase activity. Effect of chemical and enzymatic modifications of the lipoprotein on enzyme activity.

    Subbaiah, P V; Chen, C H; Bagdade, J D; Albers, J J

    1985-01-01

    The effect of various chemical and enzymatic modifications of low density lipoprotein (LDL) on its ability to activate the isolated human plasma lysolecithin acyltransferase (LAT) was studied. Removal of all lipids from LDL resulted in the complete loss of LAT activation. Removal of only neutral lipids by extraction with heptane retained up to 50% of the original activity, which was not increased further by reconstitution of the LDL with the extracted lipids. Hydrolysis of the diacylphosphoglycerides of the LDL with phospholipases resulted in complete loss of LAT activation which was partially restored by the addition of egg lecithin. Hydrolysis of more than 4% of LDL protein by trypsin led to a linear decrease in activity with complete loss of activity occurring when about 25% of the LDL protein is hydrolyzed. Modification of the arginine groups of LDL reversibly inhibited the activation of LAT. Modification of lysine residues of LDL by acetylation, acetoacetylation or succinylation also abolished its ability to activate lysolecithin acylation.

  9. Time-zero fission-fragment detector based on low-pressure multiwire proportional chambers

    Assamagan, Ketevi A; Bayatyan, G L; Carlini, R; Danagulyan, S; Eden, T; Egiyan, K; Ent, R; Fenker, H; Gan, L; Gasparian, A; Grigoryan, N K; Greenwood, Z; Gueye, P; Hashimoto, O; Johnston, K; Keppel, C; Knyazyan, S; Majewski, S; Margaryan, A; Margaryan, Yu L; Marikian, G G; Martoff, J; Mkrtchyan, H G; Parlakyan, L; Sato, Y; Sawafta, R; Simicevic, N; Tadevosyan, V; Takahashi, T; Tang, L; Vartanian, G S; Vulcan, W; Wells, S; Wood, S

    1999-01-01

    A time-zero fission fragment (FF) detector, based on the technique of low-pressure multiwire proportional chambers (LPMWPC), has been designed and constructed for the heavy hypernuclear lifetime experiment (E95-002) at Thomas Jefferson National Accelerator Facility. Its characteristics and the method of time-zero reconstruction were investigated using fission fragments from a sup 2 sup 5 sup 2 Cf spontaneous fission source. The influence of the ionization energy loss was also studied. It is shown that Heptane, Hexane, and Isobutane gases at a pressure of 1-2 Torr are all suitable for such a FF detector. As desired by experiment, a timing resolution of about 200 ps (FWHM) for a chamber size of 21x21 cm sup 2 was achieved.

  10. A comprehensive detailed kinetic mechanism for the simulation of transportation fuels

    Mehl, Marco

    2017-02-27

    This work presents a recently compiled comprehensive model for transportations fuels resulting from the collaboration of three research groups: LLNL, NUI Galway and KAUST. In the past 5 years new fundamental calculations led to significant improvements in the fidelity of detailed kinetic models of important surrogate components (e.g. n-heptane, iso-octane, toluene…) improving predictions of the combustion behavior of pure components and mixtures. By extending the newly adopted reaction rate rules, mechanisms for components that were not included in the previous LLNL gasoline and diesel surrogate mechanisms were developed (e.g. polyalkylated aromatics, cycloalkanes, components from bio-logical sources…). The major features of this updated and extended model are presented together with validation comparisons, examples of applications and future directions.

  11. Formation of La{sup 3+}, Pr{sup 3+}, Eu{sup 3+}, Er{sup 3+}, and Lu{sup 3+} complexes with chloride ions, in aqueous medium; Formacion de complejos de La{sup 3+}, Pr{sup 3+}, Eu{sup 3+}, Er{sup 3+} y Lu{sup 3+} con iones cloruro, en medio acuoso

    Fernandez R, E.; Jimenez R, M.; Solache R, M. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

    2007-07-01

    The constants of stability of the complexes of La{sup 3+}, Pr{sup 3+}, Eu{sup 3+}, Er{sup 3+}, and Lu{sup 3+} with Cl{sup -} ions, its were determined, in the aqueous medium of HCI - HClO{sub 4} and by a solvent extraction method. The dinonyl naphtalene sulfonic acid in n-heptane was used as extractant. The lanthanides concentration, it was measured by a VIS spectrophotometry method and by another radiochemical. The ions specific interaction theory (SIT) it was used for the extrapolation to ionic force 0 M. The results indicate that the stability constants of the LnCI{sup 2+} species diminishes when increasing the ion force and the charge density. (Author)

  12. Properties of multiple field ion emitters of tungsten and a simple method for improving their ionization efficiency

    Okuyama, F.; Beckey, H.D.

    1978-01-01

    The ion emission properties of the multiple tungsten emitters developed recently for field ionization mass spectrometry were investigated with the aid of a sector type mass spectrometer at emitter-cathode voltages of 10-15 kV using acetone, n-heptane and benzene as test substances. The emitters, which comprised a 10-μm tungsten filament bearing thickly arrayed microneedles of tungsten, produced very weak and unstable signals at voltages of about 10 kV, but increasing the voltage to 14 kV led to intensifying ion currents high enough to yield mass spectra of satisfactory quality. During the course of the experiments, it was observed that nucleating tungsten carbide particles on the emitter surface by means of a high-field chemical reaction with benzene vapours can significanlty promote the field ionization of gas molecules, presumably as a result of the field enhancement resulting from roughening of the surface. (Auth.)

  13. Marine Microorganisms as Source of Stereoselective Esterases and Ketoreductases: Kinetic Resolution of a Prostaglandin Intermediate

    De Vitis, Valerio; Guidi, Benedetta; Contente, Martina Letizia; Granato, Tiziana Mariarita; Conti, Paola; Molinari, Francesco; Crotti, Elena; Mapelli, Francesca; Borin, Sara S.; Daffonchio, Daniele; Romano, Diego

    2014-01-01

    A screening among bacterial strains isolated from water-brine interface of the deep hypersaline anoxic basins (DHABs) of the Eastern Mediterranean was carried out for the biocatalytical resolution of racemic propyl ester of anti-2-oxotricyclo[2.2.1.0]heptan-7-carboxylic acid (R,S)-1, a key intermediate for the synthesis of d-cloprostenol. Bacillus horneckiae 15A gave highly stereoselective reduction of (R,S)-1, whereas Halomonas aquamarina 9B enantioselectively hydrolysed (R,S)-1; in both cases, enantiomerically pure unreacted (R)-1 could be easily recovered and purified at molar conversion below 57–58 %, showing the potential of DHAB extremophile microbiome and marine-derived enzymes in stereoselective biocatalysis.

  14. Syntheses of Enantiopure Aliphatic Secondary Alcohols and Acetates by Bioresolution with Lipase B from Candida antarctica

    Richele P. Severino

    2012-07-01

    Full Text Available The lipase B from Candida antarctica (Novozym 435®, CALB efficiently catalyzed the kinetic resolution of some aliphatic secondary alcohols: (±-4-methylpentan-2-ol (1, (±-5-methylhexan-2-ol (3, (±-octan-2-ol (4, (±-heptan-3-ol (5 and (±-oct-1-en-3-ol (6. The lipase showed excellent enantioselectivities in the transesterifications of racemic aliphatic secondary alcohols producing the enantiopure alcohols (>99% ee and acetates (>99% ee with good yields. Kinetic resolution of rac-alcohols was successfully achieved with CALB lipase using simple conditions, vinyl acetate as acylating agent, and hexane as non-polar solvent.

  15. Labelling of olive oil with radioactive iodine and radioactive technetium

    Al-Dayel, O.A.F.

    1988-03-01

    Investigates labelling of olive oil with 125 iodine and with the radioactive 99mTC. A radio analytical study for 99Mo-99mTC generator is also presented. Iodine monochloride and chlormine-T methods are used for labelling olive oil and oleic acid with radioactive iodine. Diethyl ether, benzene and n-heptane have been used as solvents, with diethyl ether giving best results using iodine monochloride method. Infrared spectroscopic studies show that labelling took place at the double bond. Use of milked 99mTc gave very low yield only. A fairly higher labelling yield was achieved when 20 mg of tin chloride has been added in acetone medium than diethyl ether medium. Thin layer chromatography and paper chromatography technique were used as quality control systems. The labelled oil can be used for diagnostic and study purposes. 140 Ref

  16. A Facile Way to Fabricate Transparent Superhydrophobic Surfaces.

    Shi, Wentao; He, Ran; Yunus, Doruk E; Yang, Jie; Liu, Yaling

    2018-07-01

    A fast, easy, and low-cost way to fabricate transparent superhydrophobic (SHP) surfaces is developed. By simply mixing silica nanoparticles (SiNPs), polydimethylsiloxane (PDMS) and heptane to form a suspension, dip- or drop-coating the suspension onto different surfaces, transparent SHP surfaces can be obtained. By tuning the ratio of the three components above, transparency of the coating can reach more than 90% transmittance in the visible region, while static water contact angle of the coating can reach as high as 162°. Dynamic contact angle study shows the advancing contact angle and receding contact angle of water can be as high as 168° and 161°, and the resulting contact angle hysteresis can be as low as 7°. The reported facile way of fabricating transparent superhydrophobic (SHP) surfaces is potential for applications which need both optical transparency and self-cleaning capability, such as solar cells, optical equipment, and visible microfluidic chips.

  17. The sequential separation of strontium-90, yttrium-90, promethium-147, and cerium-144 from urine and their subsequent estimation

    Kramer, G.H.; Davies, J.M.

    1981-04-01

    A method has been developed for separating low-level activities of the beta-emitting isotopes strontium-90, yttrium-90, promethium-147 and cerium-144 from urine and aqueous solutions. They are subsequently estimated by planchet or liquid scintillation counting. The radionuclides are separated from each other and from interfering elements by solvent extraction with HDEHP (di-2-ethylhexyl phosphoric acid) in n-heptane. It is possible to separate the elements with a minimum of cross-contamination by selecting appropriate pH's and solvent concentrations. Percentage recoveries for the radionuclides are: 90 Sr, 100 +- 12; 90 Y, 65 +- 4; 147 Pm, 90 +- 8; 144 Ce, 87 +- 11. The limits of detection are: 90 Sr, 0.6 pCi; 90 Y, 0.7 pCi; 147 Pm, 1.0 pCi; 144 Ce, 0.8 pCi. (author)

  18. Phase equilibria for mixtures containing nonionic surfactant systems: Modeling and experiments

    Shin, Moon Sam; Kim, Hwayong

    2008-01-01

    Surfactants are important materials with numerous applications in the cosmetic, pharmaceutical, and food industries due to inter-associating and intra-associating bond. We present a lattice fluid equation-of-state that combines the quasi-chemical nonrandom lattice fluid model with Veytsman statistics for (intra + inter) molecular association to calculate phase behavior for mixtures containing nonionic surfactants. We also measured binary (vapor + liquid) equilibrium data for {2-butoxyethanol (C 4 E 1 ) + n-hexane} and {2-butoxyethanol (C 4 E 1 ) + n-heptane} systems at temperatures ranging from (303.15 to 323.15) K. A static apparatus was used in this study. The presented equation-of-state correlated well with the measured and published data for mixtures containing nonionic surfactant systems

  19. (Liquid + liquid) equilibria of binary systems containing hyperbranched polymer Boltorn (registered) H2004 - Experimental study and modelling in terms of lattice-cluster theory

    Domanska, Urszula; Paduszynski, Kamil; Zolek-Tryznowska, Zuzanna

    2011-01-01

    (Liquid + liquid) phase equilibria (LLE) of binary mixtures containing hyperbranched polymer Boltorn (registered) H2004 and n-alkanes (n-hexane, n-heptane, n-octane, and n-decane) were studied over the temperature range from about (260 up to 360) K. The polymer is partially miscible with n-alkanes and the solubility decreases with an increase of the chain length of the solvent. Corresponding LLE phase diagrams including spinodal and binodal (liquid + liquid) coexistence curves were calculated in terms of the statistical mechanics - based on the lattice-cluster theory, based only on the upper critical solution temperature, and the polymer chain architecture. The results show semi-qualitative agreement of predicted and experimental equilibrium compositions and temperatures. Boltorn (registered) H2004 reveals complete miscibility in the liquid phase with alcohols (C 1 -C 8 ), aromatic hydrocarbons (benzene, toluene, and thiophene), and ethers (methyl tetra-butyl ether, ethyl tetra-butyl ether, and tetrahydrofurane).

  20. Irreversible endo-Selective Diels–Alder Reactions of Substituted Alkoxyfurans: A General Synthesis of endo-Cantharimides

    Foster, Robert W; Benhamou, Laure; Porter, Michael J; Bučar, Dejan-Krešimir; Hailes, Helen C; Tame, Christopher J; Sheppard, Tom D

    2015-01-01

    The [4+2] cycloaddition of 3-alkoxyfurans with N-substituted maleimides provides the first general route for preparing endo-cantharimides. Unlike the corresponding reaction with 3H furans, the reaction can tolerate a broad range of 2-substitued furans including alkyl, aromatic, and heteroaromatic groups. The cycloaddition products were converted into a range of cantharimide products with promising lead-like properties for medicinal chemistry programs. Furthermore, the electron-rich furans are shown to react with a variety of alternative dienophiles to generate 7-oxabicyclo[2.2.1]heptane derivatives under mild conditions. DFT calculations have been performed to rationalize the activation effect of the 3-alkoxy group on a furan Diels–Alder reaction. PMID:25756502

  1. Evaluation of a Lagrangian Soot Tracking Method for the prediction of primary soot particle size under engine-like conditions

    Cai Ong, Jiun; Pang, Kar Mun; Walther, Jens Honore

    2018-01-01

    This paper reports the implementation and evaluation of a Lagrangian soot tracking (LST) method for the modeling of soot in diesel engines. The LST model employed here has the tracking capability of a Lagrangian method and the ability to predict primary soot particle sizing. The Moss-Brookes soot...... in predicting temporal soot cloud development, mean soot diameter and primary soot size distribution is evaluated using measurements of n-heptane and n-dodecane spray combustion obtained under diesel engine-like conditions. In addition, sensitivity studies are carried out to investigate the influence of soot....... A higher rate of soot oxidation due to OH causes the soot particles to be fully oxidized downstream of the flame. In general, the LST model performs better than the Eulerian method in terms of predicting soot sizing and accessing information of individual soot particles, both of which are shortcomings...

  2. Development and validation of a reduced combined biodiesel–diesel reaction mechanism

    Ng, Hoon Kiat; Gan, Suyin; Ng, Jo-Han

    2013-01-01

    In this study, a compact combined biodiesel–diesel (CBD) reaction mechanism for diesel engine simulations is proposed through the combination of three component mechanisms using a chemical class-based approach. The proposed mechanism comprises the reaction mechanisms of methyl crotonate (MC...... to characterise the combustion of fossil diesel. Here, the MC and MB mechanisms are reduced before integrating with a compact n-heptane mechanism. CHEMKIN-PRO is used as the solver for the zero-dimensional, closed homogenous reactor with a constant volume in this study. In the first phase, the mechanisms of MC...... ranging from initial temperatures of 750–1350 K, pressures of 40–60 bar and equivalence ratios of 0.4–1.5. The mechanism is generally found to accurately predict the timing and duration of ID for the combustion of each surrogate fuel. This model is also shown to be feasible for use with multidimensional...

  3. Numerical investigation of soot formation and oxidation processes under large two-stroke marine diesel engine-like conditions using integrated CFD-chemical kinetics

    Pang, Kar Mun; Karvounis, Nikolas; Walther, Jens Honore

    2016-01-01

    n-heptane mechanism and a revised multi-step soot model using laser extinction measurements of diesel soot obtained at different ambient pressure levels in an optical accessible, constant volume chamber experiment. It is revealed that ignition delay times and liftoff lengths generated using the new......In this reported work, multi-dimensional computational fluid dynamics studies of diesel combustion and soot formation processes in a constant volume combustion chamber and a marine diesel engine are carried out. The key interest here is firstly to validate the coupling of a newly developed skeletal...... using the revised soot model agrees reasonably well with the measurements in terms of peak values. The numerical model is subsequently applied to investigate the flame development, soot/nitrogen monoxide formation and heat transfer in a two-stroke, low-speed uniflow-scavenged marine diesel engine...

  4. An improved stochastic algorithm for temperature-dependent homogeneous gas phase reactions

    Kraft, M

    2003-01-01

    We propose an improved stochastic algorithm for temperature-dependent homogeneous gas phase reactions. By combining forward and reverse reaction rates, a significant gain in computational efficiency is achieved. Two modifications of modelling the temperature dependence (with and without conservation of enthalpy) are introduced and studied quantitatively. The algorithm is tested for the combustion of n-heptane, which is a reference fuel component for internal combustion engines. The convergence of the algorithm is studied by a series of numerical experiments and the computational cost of the stochastic algorithm is compared with the DAE code DASSL. If less accuracy is needed the stochastic algorithm is faster on short simulation time intervals. The new stochastic algorithm is significantly faster than the original direct simulation algorithm in all cases considered.

  5. Formation of porous surface layers in reaction bonded silicon nitride during processing

    Shaw, N. J.; Glasgow, T. K.

    1979-01-01

    Microstructural examination of reaction bonded silicon nitride (RBSN) has shown that there is often a region adjacent to the as-nitrided surfaces that is even more porous than the interior of this already quite porous material. Because this layer of large porosity is considered detrimental to both the strength and oxidation resistance of RBSN, a study was undertaken to determine if its formation could be prevented during processing. All test bars studied were made from a single batch of Si powder which was milled for 4 hours in heptane in a vibratory mill using high density alumina cylinders as the grinding media. After air drying the powder, bars were compacted in a single acting die and hydropressed.

  6. Manufacture of TATB and TNT from Biosynthesized Phloroglucinols

    2010-07-01

    calculated for C7H5N3O9: C, 30.56; H, 1.83; N, 15.27. Found: C, 30.12; H, 1.54; N, 14.83. Slow diffusion of n-heptane into a chloroform solution of 2...2.1 g, 91% yield) as a slow crystallizing yellow oil. 1H NMR (CDCl3) δ 0.94 (t, 3H, propyl CH3), 1.73 (m, 3H, propyl CH2), 4.02 (s, 6H, O-CH3), 4.10...t, 2H, propyl CH2); 13C NMR (CDCl3) δ 9.78, 23.14, 64.48, 79.68, 135.55, 26 135,99, 146.68, 147.19. Elemental analysis calculated for C11H13N3O9: C

  7. Synthesis and evaluation of copolymer based on cardanol and styrene on the stability of asphaltenes; Sintese e avaliacao de copolimero a base de cardanol e estireno sobre a estabilidade dos asfaltenos

    Loureiro, Tatiana S.; Spinelli, Luciana S., E-mail: tatianaloureiro@ima.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas

    2015-07-01

    The destabilization of asphaltenes in crude oil mainly happens due to variations in pressure, temperature and oil composition, causing significant losses. Polymers containing specific groups can be used as asphaltenes stabilizers and thus, avoid your precipitation, or as asphaltenes flocculants to assist the removal of suspended particles in a particular oil. The monitoring of asphaltenes precipitation is usually evaluated by tests with variation in stability of asphaltenes in function of adding a flocculant solvent. In this work, it was evaluated the influence of a synthesized copolymer based on cardanol and styrene on the stability of asphaltenes. The stability of asphaltenes was monitored by precipitation tests induced by a flocculant agent (n-heptane), using an ultraviolet-visible (UV-Vis) spectrometer. The structural characterization of copolymer was performed by FTIR and {sup 1}H NMR. The results showed that copolymer can act as asphaltene flocculant. (author)

  8. Time-zero fission-fragment detector based on low-pressure multiwire proportional chambers

    Assamagan, K.; Baker, K.; Bayatyan, G.; Carlini, R.; Danagoulian, S.; Eden, T.; Egiyan, K.; Ent, R.; Fenker, H.; Gan, L.; Gasparian, A.; Grigoryan, N.; Greenwood, Z.; Gueye, P.; Hashimoto, O.; Johnston, K.; Keppel, C.; Knyazyan, S.; Majewski, S.; Margaryan, A.; Margaryan, Yu.; Marikyan, G.; Martoff, J.; Mkrtchyan, H.; Parlakyan, L.; Sato, Y.; Sawafta, R.; Simicevic, N.; Tadevosyan, V.; Takahashi, T.; Tang, L.; Vartanyan, G.; Vulcan, W.; Wells, S.; Wood, S.

    1999-01-01

    A time-zero fission fragment (FF) detector, based on the technique of low-pressure multiwire proportional chambers (LPMWPC), has been designed and constructed for the heavy hypernuclear lifetime experiment (E95-002) at Thomas Jefferson National Accelerator Facility. Its characteristics and the method of time-zero reconstruction were investigated using fission fragments from a 252 Cf spontaneous fission source. The influence of the ionization energy loss was also studied. It is shown that Heptane, Hexane, and Isobutane gases at a pressure of 1-2 Torr are all suitable for such a FF detector. As desired by experiment, a timing resolution of about 200 ps (FWHM) for a chamber size of 21x21 cm 2 was achieved

  9. The phase behavior of a hard sphere chain model of a binary n-alkane mixture

    Malanoski, A. P.; Monson, P. A.

    2000-01-01

    Monte Carlo computer simulations have been used to study the solid and fluid phase properties as well as phase equilibrium in a flexible, united atom, hard sphere chain model of n-heptane/n-octane mixtures. We describe a methodology for calculating the chemical potentials for the components in the mixture based on a technique used previously for atomic mixtures. The mixture was found to conform accurately to ideal solution behavior in the fluid phase. However, much greater nonidealities were seen in the solid phase. Phase equilibrium calculations indicate a phase diagram with solid-fluid phase equilibrium and a eutectic point. The components are only miscible in the solid phase for dilute solutions of the shorter chains in the longer chains. (c) 2000 American Institute of Physics

  10. Marine Microorganisms as Source of Stereoselective Esterases and Ketoreductases: Kinetic Resolution of a Prostaglandin Intermediate

    De Vitis, Valerio

    2014-09-30

    A screening among bacterial strains isolated from water-brine interface of the deep hypersaline anoxic basins (DHABs) of the Eastern Mediterranean was carried out for the biocatalytical resolution of racemic propyl ester of anti-2-oxotricyclo[2.2.1.0]heptan-7-carboxylic acid (R,S)-1, a key intermediate for the synthesis of d-cloprostenol. Bacillus horneckiae 15A gave highly stereoselective reduction of (R,S)-1, whereas Halomonas aquamarina 9B enantioselectively hydrolysed (R,S)-1; in both cases, enantiomerically pure unreacted (R)-1 could be easily recovered and purified at molar conversion below 57–58 %, showing the potential of DHAB extremophile microbiome and marine-derived enzymes in stereoselective biocatalysis.

  11. Acidity characterization of a titanium and sulfate modified vermiculite

    Hernandez, W.Y.; Centeno, M.A.; Odriozola, J.A.; Moreno, S.; Molina, R.

    2008-01-01

    A natural vermiculite has been modified with titanium and sulfated by the intercalation and impregnation method in order to optimize the acidity of the clay mineral, and characterization of samples were analyzed by X-ray fluorescence (XRF), X-ray diffraction (XRD), nitrogen adsorption isotherms, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and temperature programmed desorption with ammonia (TPD-NH 3 ). All the modified solids have a significantly higher number of acidic sites with respect to the parent material and in all of these, Broensted as well as Lewis acidity are identified. The presence of sulfate appears not to increase the number of acidic centers in the modified clay. For the materials sulfated with the intercalation method, it is observed that the strength of the acidic sites found in the material increases with the nominal sulfate/metal ratio. Nevertheless, when elevated quantities of sulfur are deposited, diffusion problems in the heptane reaction appear

  12. Nd2Fe14C-based magnet with better permanent magnetic properties prepared by a simple mechanochemical method

    Geng, Hongmin; Ji, Yuan; Zhang, Jingjing; Gao, Yuchao; Yan, Yu; Wang, Wenquan; Su, Feng; Du, Xiaobo

    2017-11-01

    Nd2Fe14C-based magnet is prepared by a mechanochemical method, namely high-energy ball-milling Nd2Fe11Bx (x = 0-0.15) alloy in heptane (C7H16), followed by annealing to 850 °C in vacuum. Under the action of high-energy ball-milling, Nd2Fe11Bx react with heptane to form NdH2+δ, Fe-(CB), C, etc. H2 is released and Nd2Fe17, Nd2Fe17Cx (x = 0-3), Nd2Fe14C, Nd carbides and α-Fe are formed in the subsequent annealing. C amount depends on ball-milling time t. Long time ball milling or high C content suppresses the formation of 2:17 phase and favors the formation of 2:14:1 phase in the final products. Excessive ball-milling results in the quick increase of α-Fe. The maximum of magnetically hard Nd2Fe14C is obtained at t = 4 h. For Nd2Fe11 samples, there exists considerable quantity of Nd carbides and α-Fe phase appears earlier and increases rapidly with extending the ball-milling time t. The addition of B element shortens the ball-milling time of the formation of maximum Nd2Fe14C and prominently suppresses the formation of Nd carbide and α-Fe. The optimum magnetic properties, coercivity iHc of 1193.7 kA/m, remanence Mr of 580.9 kA/m, maximum magnetic energy product (BH)max of 91.7 kJ/m3 is approaching to its theoretic value of 99.2 kJ/m3 for isotropic Nd2Fe14C magnet, are obtained in Nd2Fe11B0.06 alloy ball milled for 3.5 h.

  13. Synthesis and characterization of oleic acid surface modified magnetic iron oxide nanoparticles by using biocompatible w/o microemulsion for heavy metal removal

    Rose, Laili Che; Suhaimi, Hamdan; Mamat, Mazidah; Lik, Thang Zhe

    2017-09-01

    Oleic acid modified magnetic iron oxide nanoparticles (OA-MIONs) was prepared for removal of Cu2+ ion from aqueous solution. OA-MIONs was prepared by W/O microemulsion template which composed of mixed non-ionic surfactants and 1-hexanol as emulsifier. The effect of weight ratio of the constituent of microemulsion template on the physical and chemical properties of OA-MIONs was studied by characterization using Fourier transform infrared (FT-IR), scanning electron microscopy (SEM) and X-ray powder diffraction (XRD) analysis. FT-IR spectra showed that all templates shared similar chemical structure with slight difference in the peak intensity. Scanning electron micrograph illustrated that the OA-MIONs synthesized via template with the lowest weight ratio of emulsifier to heptane had a more regular spherical shape and was well-distributed. XRD had confirmed that the identity of synthesized OA-MIONs was Fe3O4. Based on the characterization result, the template with lowest weight ratio of emulsifier to heptane was chosen for the heavy metal adsorption study. The adsorption capacity OA-MIONs as a function of pH, contact time and adsorbent dosage were studied. The adsorption process reached equilibrium for 90 minutes and successfully adsorbed 43% of Cu2+ ion from aqueous solution. The adsorption behavior was well described by Langmuir isotherm. The maximum adsorption capacity was determined and found to be 555.56 mg/g. The value of Langmuir equilibrium parameter, RL was found between 0 and 1, suggested that a favorable monolayer adsorption process had taken out.

  14. Fast neutron spectroscopy with tensioned metastable fluid detectors

    Grimes, T.F.; Taleyarkhan, R.P., E-mail: rusi@purdue.edu

    2016-09-11

    This paper describes research into development of a rapid-turnaround, neutron-spectroscopy capable (gamma-beta blind), high intrinsic efficiency sensor system utilizing the tensioned metastable fluid detector (TMFD) architecture. The inability of prevailing theoretical models (developed successfully for the classical bubble chamber) to adequately predict detection thresholds for tensioned metastable fluid conditions is described. Techniques are presented to overcome these inherent shortcomings, leading thereafter, to allow successful neutron spectroscopy using TMFDs – via the newly developed Single Atom Spectroscopy (SAS) approach. SAS also allows for a unique means for rapidly determining neutron energy thresholds with TMFDs. This is accomplished by simplifying the problem of determining Cavitation Detection Events (CDEs) arising from neutron interactions with one in which several recoiling atom species contribute to CDEs, to one in which only one dominant recoil atom need be considered. The chosen fluid is Heptane (C{sub 7}H{sub 16}) for which only recoiling C atoms contribute to CDEs. Using the SAS approach, the threshold curve for Heptane was derived using isotope neutron source data, and then validated against experiments with mono-energetic (2.45/14 MeV) neutrons from D-D and D-T accelerators. Thereafter the threshold curves were used to produce the response matrix for various geometries. The response matrices were in turn combined with experimental data to recover the continuous spectra of fission (Cf-252) and (α,n) Pu–Be isotopic neutron sources via an unfolding algorithm. A generalized algorithm is also presented for performing neutron spectroscopy using any other TMFD fluid that meets the SAS approach assumptions.

  15. Conformation of Single Pentablock Ionomer Chains in Dilute Solutions

    Aryal, Dipak [Clemson Univ., SC (United States); Perahia, Dvora [Clemson Univ., SC (United States); Grest, Gary S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-04-01

    The conformation of single chain pentablock ionomers (A-B-C-B-A) containing randomly sulfonated polystyrene in the center block, tethered to poly-ethylene-r-propylene end-capped by poly-t-butyl styrene is studied in dilute solutions by molecular dynamics simulations. Multi-block copolymers offer a means to tailor several properties into one molecule, taking advantage of their rich phase diagram together with unique properties of specific blocks. For this pentablock the ionic block facilitates transport while the A and B components are incorporated for mechanical stability. The present study investigates the confirmation of a single chain of pentablock ionomer of molecular weight Mw ~ 50,000 g/mol and sulfonated polystyrene of the same molecular weight as that of the center block for six sulfonation fractions f from f=0.0-0.55. For the sulfonated systems Na+ counterions are included. Results for the equilibrium conformation of the chains and the three blocks in water and 1:1 mixture of cyclohexane and n-heptane are compared to simulations in implicit poor solvents with dielectric constants ε =1.0 and 77.73. In water, the pentablock is collapsed with sulfonated groups on the outer surface. As the sulfonation fraction f increases, the ionic, center block is increasingly segregated from the hydrophobic regions. In the 1:1 mixture of cyclohexane and heptane both the flexible and end blocks are swollen while the center ionic block is collasped for f>0, while for f=0 all blocks are swollen. In both implicit poor solvents the pentablock is collapsed into a nearly spherical shape for all f. The sodium counterions are dispersed widely throughout the simulation cell for both water and ε =77.73 whereas for ε =1.0 the counterions are largely condensed on the collapsed pentablock.

  16. Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

    Singh, Eshan

    2017-03-28

    The blending of ethanol with primary reference fuel (PRF) mixtures comprising n-heptane and iso-octane is known to exhibit a non-linear octane response; however, the underlying chemistry and intermolecular interactions are poorly understood. Well-designed experiments and numerical simulations are required to understand these blending effects and the chemical kinetic phenomenon responsible for them. To this end, HCCI engine experiments were previously performed at four different conditions of intake temperature and engine speed for various PRF/ethanol mixtures. Transfer functions were developed in the HCCI engine to relate PRF mixture composition to autoignition tendency at various compression ratios. The HCCI blending octane number (BON) was determined for mixtures of 2-20 vol % ethanol with PRF70. In the present work, the experimental conditions were considered to perform zero-dimensional HCCI engine simulations with detailed chemical kinetics for ethanol/PRF blends. The simulations used the actual engine geometry and estimated intake valve closure conditions to replicate the experimentally measured start of combustion (SOC) for various PRF mixtures. The simulated HCCI heat release profiles were shown to reproduce the experimentally observed trends, specifically on the effectiveness of ethanol as a low temperature chemistry inhibitor at various concentrations. Detailed analysis of simulated heat release profiles and the evolution of important radical intermediates (e.g., OH and HO) were used to show the effect of ethanol blending on controlling reactivity. A strong coupling between the low temperature oxidation reactions of ethanol and those of n-heptane and iso-octane is shown to be responsible for the observed blending effects of ethanol/PRF mixtures.

  17. Numerical studies of spray combustion processes of palm oil biodiesel and diesel fuels using reduced chemical kinetic mechanisms

    Kuti, Olawole

    2014-04-01

    Spray combustion processes of palm oil biodiesel (PO) and conventional diesel fuels were simulated using the CONVERGE CFD code. Thermochemical and reaction kinetic data (115 species and 460 reactions) by Luo et al. (2012) and Lu et al. (2009) (68 species and 283 reactions) were implemented in the CONVERGE CFD to simulate the spray and combustion processes of the two fuels. Tetradecane (C14H30) and n- heptane (C7H 16) were used as surrogates for diesel. For the palm biodiesel, the mixture of methyl decanoate (C11H20O2), methyl-9-decenoate (C11H19O2) and n-heptane was used as surrogate. The palm biodiesel surrogates were combined in proportions based on the previous GC-MS results for the five major biodiesel components namely methyl palmitate, methyl stearate, methyl oleate, methyl linoleate and methyl linolenate. The Favre-Averaged Navier Stokes based simulation using the renormalization group (RNG) k-ε turbulent model was implemented in the numerical calculations of the spray formation processes while the SAGE chemical kinetic solver is used for the detailed kinetic modeling. The SAGE chemical kinetic solver is directly coupled with the gas phase calculations by renormalization group (RNG) k-ε turbulent model using a well-stirred reactor model. Validations of the spray liquid length, ignition delay and flame lift-off length data were performed against previous experimental results. The simulated liquid length, ignition delay and flame lift-off length were validated at an ambient density of 15kg/m3, and injection pressure conditions of 100, 200 and 300 MPa were utilized. The predicted liquid length, ignition delay and flame lift-off length agree with the trends obtained in the experimental data at all injection conditions. Copyright © 2014 SAE International.

  18. Simulating HCCI Blending Octane Number of Primary Reference Fuel with Ethanol

    Singh, Eshan; Waqas, Muhammad; Johansson, Bengt; Sarathy, Mani

    2017-01-01

    The blending of ethanol with primary reference fuel (PRF) mixtures comprising n-heptane and iso-octane is known to exhibit a non-linear octane response; however, the underlying chemistry and intermolecular interactions are poorly understood. Well-designed experiments and numerical simulations are required to understand these blending effects and the chemical kinetic phenomenon responsible for them. To this end, HCCI engine experiments were previously performed at four different conditions of intake temperature and engine speed for various PRF/ethanol mixtures. Transfer functions were developed in the HCCI engine to relate PRF mixture composition to autoignition tendency at various compression ratios. The HCCI blending octane number (BON) was determined for mixtures of 2-20 vol % ethanol with PRF70. In the present work, the experimental conditions were considered to perform zero-dimensional HCCI engine simulations with detailed chemical kinetics for ethanol/PRF blends. The simulations used the actual engine geometry and estimated intake valve closure conditions to replicate the experimentally measured start of combustion (SOC) for various PRF mixtures. The simulated HCCI heat release profiles were shown to reproduce the experimentally observed trends, specifically on the effectiveness of ethanol as a low temperature chemistry inhibitor at various concentrations. Detailed analysis of simulated heat release profiles and the evolution of important radical intermediates (e.g., OH and HO) were used to show the effect of ethanol blending on controlling reactivity. A strong coupling between the low temperature oxidation reactions of ethanol and those of n-heptane and iso-octane is shown to be responsible for the observed blending effects of ethanol/PRF mixtures.

  19. Investigation of spray characteristics from a low-pressure common rail injector for use in a homogeneous charge compression ignition engine

    Lee, Kihyung; Reitz, Rolf D.

    2004-03-01

    Homogeneous charge compression ignition (HCCI) combustion provides extremely low levels of pollutant emissions, and thus is an attractive alternative for future IC engines. In order to achieve a uniform mixture distribution within the engine cylinder, the characteristics of the fuel spray play an important role in the HCCI engine concept. It is well known that high-pressure common rail injection systems, mainly used in diesel engines, achieve poor mixture formation because of the possibility of direct fuel impingement on the combustion chamber surfaces. This paper describes spray characteristics of a low-pressure common rail injector which is intended for use in an HCCI engine. Optical diagnostics including laser diffraction and phase Doppler methods, and high-speed camera photography, were applied to measure the spray drop diameter and to investigate the spray development process. The drop sizing results of the laser diffraction method were compared with those of a phase Doppler particle analyser (PDPA) to validate the accuracy of the experiments. In addition, the effect of fuel properties on the spray characteristics was investigated using n-heptane, Stoddard solvent (gasoline surrogate) and diesel fuel because HCCI combustion is sensitive to the fuel composition. The results show that the injector forms a hollow-cone sheet spray rather than a liquid jet, and the atomization efficiency is high (small droplets are produced). The droplet SMD ranged from 15 to 30 µm. The spray break-up characteristics were found to depend on the fuel properties. The break-up time for n-heptane is shorter and the drop SMD is smaller than that of Stoddard solvent and diesel fuel.

  20. Ignition of a lean PRF/air mixture under RCCI/SCCI conditions: Chemical aspects

    Luong, Minh Bau

    2016-10-10

    Chemical aspects of the ignition of a primary reference fuel (PRF)/air mixture under reactivity controlled compression ignition (RCCI) and stratified charge compression ignition (SCCI) conditions are investigated by analyzing two-dimensional direct numerical simulation (DNS) data with chemical explosive mode (CEM) analysis. CEMA is adopted to provide fundamental insights into the ignition process by identifying controlling species and elementary reactions at different locations and times. It is found that at the first ignition delay, low-temperature chemistry (LTC) represented by the isomerization of alkylperoxy radical, chain branching reactions of keto-hydroperoxide, and H-atom abstraction of n-heptane is predominant for both RCCI and SCCI combustion. In addition, explosion index and participation index analyses together with conditional means on temperature verify that low-temperature heat release (LTHR) from local mixtures with relatively-high n-heptane concentration occurs more intensively in RCCI combustion than in SCCI combustion, which ultimately advances the overall RCCI combustion and distributes its heat release rate over time. It is also found that at the onset of the main combustion, high-temperature heat release (HTHR) occurs primarily in thin deflagrations where temperature, CO, and OH are found to be the most important species for the combustion. The conversion reaction of CO to CO and hydrogen chemistry are identified as important reactions for HTHR. The overall RCCI/SCCI combustion can be understood by mapping the variation of 2-D RCCI/SCCI combustion in temperature space onto the temporal evolution of 0-D ignition.

  1. Evaluation of Vitamin D3 and D2 Stability in Fortified Flat Bread Samples During Dough Fermentation, Baking and Storage.

    Tabibian, Mehrnaz; Torbati, Mohammadali; Afshar Mogaddam, Mohammad Reza; Mirlohi, Maryam; Sadeghi, Malihe; Mohtadinia, Javad

    2017-06-01

    Purpose: Vitamin D, a fat-soluble secosteroid, has a significant role in bone metabolism and helps calcium absorption in the body. Since vitamin D concentration is altered in fortified foods and dietary supplements, the actual amount of vitamin D may differ from the label value. Methods: In this study, the concentrations of vitamin D 2 and D 3 of fortified bread sample were analytically determined. For this purpose, dough or homogenized bread sample was saponified using potassium hydroxide solution (30%, w/v) at 80°C, and the saponified analytes were extracted into n -heptane followed by liquid-liquid extraction. Then n -heptane fraction was evaporated to dryness and the sample was reconstituted in methanol. The effect of different parameters was evaluated by one variable at one-time strategy. Results: The analytes concentrations were evaluated in dough fermentation, baking and storage steps. The effect of temperature in dough fermentation and baking was evaluated at the range of 5-30 and 200-250°C, respectively. Also, the fermentation time was studied in the range of 0-120 min. The analytes concentrations were followed for 1 to 5 days after baking. The results indicated that dough fermentation temperature has no significant effect on the concentration of the analytes. On the other hand, when the dough fermentation time and baking temperature are increased, the analytes concentrations are decreased. Also, the storage duration of the spiked bread samples decreased the analytes concentrations after one day. Conclusion: Based on the obtained results, baking the dough at high temperatures lead to decrease in vitamin levels.

  2. Recent progress in gasoline surrogate fuels

    Sarathy, Mani

    2017-12-06

    Petroleum-derived gasoline is currently the most widely used fuel for transportation propulsion. The design and operation of gasoline fuels is governed by specific physical and chemical kinetic fuel properties. These must be thoroughly understood in order to improve sustainable gasoline fuel technologies in the face of economical, technological, and societal challenges. For this reason, surrogate mixtures are formulated to emulate the thermophysical, thermochemical, and chemical kinetic properties of the real fuel, so that fundamental experiments and predictive simulations can be conducted. Early studies on gasoline combustion typically adopted single component or binary mixtures (n-heptane/isooctane) as surrogates. However, the last decade has seen rapid progress in the formulation and utilization of ternary mixtures (n-heptane/isooctane/toluene), as well as multicomponent mixtures that span the entire carbon number range of gasoline fuels (C4–C10). The increased use of oxygenated fuels (ethanol, butanol, MTBE, etc.) as blending components/additives has also motivated studies on their addition to gasoline fuels. This comprehensive review presents the available experimental and chemical kinetic studies which have been performed to better understand the combustion properties of gasoline fuels and their surrogates. Focus is on the development and use of surrogate fuels that emulate real fuel properties governing the design and operation of engines. A detailed analysis is presented for the various classes of compounds used in formulating gasoline surrogate fuels, including n-paraffins, isoparaffins, olefins, naphthenes, and aromatics. Chemical kinetic models for individual molecules and mixtures of molecules to emulate gasoline surrogate fuels are presented. Despite the recent progress in gasoline surrogate fuel combustion research, there are still major gaps remaining; these are critically discussed, as well as their implications on fuel formulation and engine

  3. Analysis of volatile compounds of Ilex paraguariensis A. St. - Hil. and its main adulterating species Ilex theizans Mart. ex Reissek and Ilex dumosa Reissek Análise de compostos voláteis de Ilex paraguariensis A. St. - Hil. e suas principais espécies adulterantes Ilex theizans Mart. ex Reissek e Ilex dumosa Reissek

    Rogério Marcos Dallago

    2011-12-01

    Full Text Available The adulteration of the product Ilex paraguariensis with other Ilex species is a mAjor problem for maté tea producers. In this work, three species of Ilex were evaluated for their volatile composition by headspace solid phase microextraction coupled to gas chromatography and mass spectrum detector (HS-SPME/GC-MS. The adulterating species I. dumnosa and I. theizans Mart. ex Reissek presented a different profile of volatile organic compounds when compared to I. paraguariensis. Aldehydes methyl-butanal, pentanal, hexanal, heptanal and nonanal were detected only in the adulterating species. This result suggests that such compounds are potential chemical markers for identification of adulteration and quality analysis of products based on Ilex paraguariensis.A adulteração do produto Ilex paraguariensis com outras espécies de Ilex é um dos principais problemas dos produtores de erva-mate. Neste trabalho, três espécies de Ilex foram avaliadas quanto à sua composição volátil por microextração em fase sólida acoplada à cromatografia gasosa e detector de espectro de massas (HS-SPME/GC-MS. As espécies adulterantes I. dumnosa e I. theizans Mart. ex Reissek apresentaram um perfil diferente de compostos orgânicos voláteis, quando comparadas com a I. paraguariensis. Os aldeídos metil-butanal, pentanal, hexanal, heptanal e nonanal foram detectados apenas nas espécies adulterantes. Esse resultado sugere que esses compostos químicos são marcadores potenciais para a identificação de adulteração e análise da qualidade dos produtos à base de Ilex paraguariensis.

  4. Rheological properties of hydrate suspensions in asphaltenic crude oils; Proprietes rheologiques de suspensions d'hydrate dans des bruts asphalteniques

    Marques de Toledo Camargo, R.

    2001-03-01

    The development of offshore oil exploitation under increasing water depths has forced oil companies to increase their understanding of gas hydrate formation and transportation in multiphase flow lines in which a liquid hydrocarbon phase is present. This work deals with the flow behaviour of hydrate suspensions in which a liquid hydrocarbon is the continuous phase. Three different liquid hydrocarbons are used: an asphaltenic crude oil, a condensate completely free of asphaltenes and a mixture between the asphaltenic oil and heptane. The rheological characterisation of hydrate suspensions is the main tool employed. Two original experimental devices are used: a PVT cell adapted to operate as a Couette type rheometer and a semi-industrial flow loop. Hydrate suspensions using the asphaltenic oil showed shear-thinning behaviour and thixotropy. This behaviour is typically found in flocculated systems, in which the particles attract each other forming flocs of aggregated particles at low shear rates. The suspensions using the condensate showed Newtonian behaviour. Their relative viscosities were high, which suggests that an aggregation process between hydrate particles takes. place during hydrate formation. Finally, hydrate suspensions using the mixture asphaltenic oil-heptane showed shear-thinning behaviour, thixotropy and high relative viscosity. From these results it can be inferred that, after the achievement of the hydrate formation process, the attractive forces between hydrate particles are weak. making unlikely pipeline obstruction by an aggregation process. Nevertheless, during the hydrate formation, these attractive forces can be sufficiently high. It seems that the hydrate surface wettability is an important parameter in this phenomena. (author)

  5. Autoignition of straight-run naphtha: A promising fuel for advanced compression ignition engines

    Alabbad, Mohammed

    2017-11-24

    Naphtha, a low-octane distillate fuel, has been proposed as a promising low-cost fuel for advanced compression ignition engine technologies. Experimental and modelling studies have been conducted in this work to assess autoignition characteristics of naphtha for use in advanced engines. Ignition delay times of a certified straight-run naphtha fuel, supplied by Haltermann Solutions, were measured in a shock tube and a rapid comparison machine over wide ranges of experimental conditions (20 and 60 bar, 620–1223 K, ϕ = 0.5, 1 and 2). The Haltermann straight-run naphtha (HSRN) has research octane number (RON) of 60 and motor octane number (MON) of 58.3, with carbon range spanning C3–C9. Reactivity of HSRN was compared, via experiments and simulations, with three suitably formulated surrogates: a two-component PRF (n-heptane/iso-octane) surrogate, a three-component TPRF (toluene/n-heptane/iso-octane) surrogate, and a six-component surrogate. All surrogates reasonably captured the ignition delays of HSRN at high and intermediate temperatures. However, at low temperatures (T < 750 K), the six-component surrogate performed the best in emulating the reactivity of naphtha fuel. Temperature sensitivity and rate of production analyses revealed that the presence of cyclo-alkanes in naphtha inhibits the overall fuel reactivity. Zero-dimensional engine simulations showed that PRF is a good autoignition surrogate for naphtha at high engine loads, however, the six-component surrogate is needed to match the combustion phasing of naphtha at low engine loads.

  6. Recent progress in gasoline surrogate fuels

    Sarathy, Mani; Farooq, Aamir; Kalghatgi, Gautam T.

    2017-01-01

    Petroleum-derived gasoline is currently the most widely used fuel for transportation propulsion. The design and operation of gasoline fuels is governed by specific physical and chemical kinetic fuel properties. These must be thoroughly understood in order to improve sustainable gasoline fuel technologies in the face of economical, technological, and societal challenges. For this reason, surrogate mixtures are formulated to emulate the thermophysical, thermochemical, and chemical kinetic properties of the real fuel, so that fundamental experiments and predictive simulations can be conducted. Early studies on gasoline combustion typically adopted single component or binary mixtures (n-heptane/isooctane) as surrogates. However, the last decade has seen rapid progress in the formulation and utilization of ternary mixtures (n-heptane/isooctane/toluene), as well as multicomponent mixtures that span the entire carbon number range of gasoline fuels (C4–C10). The increased use of oxygenated fuels (ethanol, butanol, MTBE, etc.) as blending components/additives has also motivated studies on their addition to gasoline fuels. This comprehensive review presents the available experimental and chemical kinetic studies which have been performed to better understand the combustion properties of gasoline fuels and their surrogates. Focus is on the development and use of surrogate fuels that emulate real fuel properties governing the design and operation of engines. A detailed analysis is presented for the various classes of compounds used in formulating gasoline surrogate fuels, including n-paraffins, isoparaffins, olefins, naphthenes, and aromatics. Chemical kinetic models for individual molecules and mixtures of molecules to emulate gasoline surrogate fuels are presented. Despite the recent progress in gasoline surrogate fuel combustion research, there are still major gaps remaining; these are critically discussed, as well as their implications on fuel formulation and engine

  7. Modulation of protein fermentation does not affect fecal water toxicity: a randomized cross-over study in healthy subjects.

    Karen Windey

    Full Text Available Protein fermentation results in production of metabolites such as ammonia, amines and indolic, phenolic and sulfur-containing compounds. In vitro studies suggest that these metabolites might be toxic. However, human and animal studies do not consistently support these findings. We modified protein fermentation in healthy subjects to assess the effects on colonic metabolism and parameters of gut health, and to identify metabolites associated with toxicity.After a 2-week run-in period with normal protein intake (NP, 20 healthy subjects followed an isocaloric high protein (HP and low protein (LP diet for 2 weeks in a cross-over design. Protein fermentation was estimated from urinary p-cresol excretion. Fecal metabolite profiles were analyzed using GC-MS and compared using cluster analysis. DGGE was used to analyze microbiota composition. Fecal water genotoxicity and cytotoxicity were determined using the Comet assay and the WST-1-assay, respectively, and were related to the metabolite profiles.Dietary protein intake was significantly higher during the HP diet compared to the NP and LP diet. Urinary p-cresol excretion correlated positively with protein intake. Fecal water cytotoxicity correlated negatively with protein fermentation, while fecal water genotoxicity was not correlated with protein fermentation. Heptanal, 3-methyl-2-butanone, dimethyl disulfide and 2-propenyl ester of acetic acid are associated with genotoxicity and indole, 1-octanol, heptanal, 2,4-dithiapentane, allyl-isothiocyanate, 1-methyl-4-(1-methylethenyl-benzene, propionic acid, octanoic acid, nonanoic acid and decanoic acid with cytotoxicity.This study does not support a role of protein fermentation in gut toxicity. The identified metabolites can provide new insight into colonic health.ClinicalTrial.gov NCT01280513.

  8. NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} in an oxidizing medium; Elimination des NO{sub x} par le coke depose sur Pt/Al{sub 2}O{sub 3} en milieu oxydant

    Lunati, S

    1997-12-12

    NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} was studied in excess oxygen. Continuous analysis of the effluent was performed with a mass spectrometer. The coking reaction was carried out under reducing conditions with two different coking agents: cyclopentane and heptanal. In general, NO{sub x} reduction by coke deposited on Pt/Al{sub 2}O{sub 3} occurs in a wide temperature range (200 deg Cheptanal which contains oxygenated functions (carbonyl and hydroxyl groups) within the carbon structure, is more selective and reduce NO{sub x} at lower temperature than a coke made from cyclopentane which does not contain these functional groups. Based on our results, we proposed a `dual-site` reaction for NO{sub x} reduction on coked Pt/Al{sub 2}O{sub 3} catalyst. Platinum allows O{sub 2} activation by dissociative adsorption, and NO{sub 2} formation by oxidation of NO. NO{sub x} reduction occurs on carbon deposits. Reaction between NO{sub x} and coke leads to the formation of N-containing species which are decomposed in CI{sub 2}, H{sub 2}O, N{sub 2} and N{sub 2}O by reaction with activated O{sub 2}. (author) 205 refs.

  9. Autoignition of straight-run naphtha: A promising fuel for advanced compression ignition engines

    Alabbad, Mohammed; Issayev, Gani; Badra, Jihad; Voice, Alexander K.; Giri, Binod; Djebbi, Khalil; Ahmed, Ahfaz; Sarathy, Mani; Farooq, Aamir

    2017-01-01

    Naphtha, a low-octane distillate fuel, has been proposed as a promising low-cost fuel for advanced compression ignition engine technologies. Experimental and modelling studies have been conducted in this work to assess autoignition characteristics of naphtha for use in advanced engines. Ignition delay times of a certified straight-run naphtha fuel, supplied by Haltermann Solutions, were measured in a shock tube and a rapid comparison machine over wide ranges of experimental conditions (20 and 60 bar, 620–1223 K, ϕ = 0.5, 1 and 2). The Haltermann straight-run naphtha (HSRN) has research octane number (RON) of 60 and motor octane number (MON) of 58.3, with carbon range spanning C3–C9. Reactivity of HSRN was compared, via experiments and simulations, with three suitably formulated surrogates: a two-component PRF (n-heptane/iso-octane) surrogate, a three-component TPRF (toluene/n-heptane/iso-octane) surrogate, and a six-component surrogate. All surrogates reasonably captured the ignition delays of HSRN at high and intermediate temperatures. However, at low temperatures (T < 750 K), the six-component surrogate performed the best in emulating the reactivity of naphtha fuel. Temperature sensitivity and rate of production analyses revealed that the presence of cyclo-alkanes in naphtha inhibits the overall fuel reactivity. Zero-dimensional engine simulations showed that PRF is a good autoignition surrogate for naphtha at high engine loads, however, the six-component surrogate is needed to match the combustion phasing of naphtha at low engine loads.

  10. Exhaled volatile substances mirror clinical conditions in pediatric chronic kidney disease.

    Juliane Obermeier

    Full Text Available Monitoring metabolic adaptation to chronic kidney disease (CKD early in the time course of the disease is challenging. As a non-invasive technique, analysis of exhaled breath profiles is especially attractive in children. Up to now, no reports on breath profiles in this patient cohort are available. 116 pediatric subjects suffering from mild-to-moderate CKD (n = 48 or having a functional renal transplant KTx (n = 8 and healthy controls (n = 60 matched for age and sex were investigated. Non-invasive quantitative analysis of exhaled breath profiles by means of a highly sensitive online mass spectrometric technique (PTR-ToF was used. CKD stage, the underlying renal disease (HUS; glomerular diseases; abnormalities of kidney and urinary tract or polycystic kidney disease and the presence of a functional renal transplant were considered as classifiers. Exhaled volatile organic compound (VOC patterns differed between CKD/ KTx patients and healthy children. Amounts of ammonia, ethanol, isoprene, pentanal and heptanal were higher in patients compared to healthy controls (556, 146, 70.5, 9.3, and 5.4 ppbV vs. 284, 82.4, 49.6, 5.30, and 2.78 ppbV. Methylamine concentrations were lower in the patient group (6.5 vs 10.1 ppbV. These concentration differences were most pronounced in HUS and kidney transplanted patients. When patients were grouped with respect to degree of renal failure these differences could still be detected. Ammonia accumulated already in CKD stage 1, whereas alterations of isoprene (linked to cholesterol metabolism, pentanal and heptanal (linked to oxidative stress concentrations were detectable in the breath of patients with CKD stage 2 to 4. Only weak associations between serum creatinine and exhaled VOCs were noted. Non-invasive breath testing may help to understand basic mechanisms and metabolic adaptation accompanying progression of CKD. Our results support the current notion that metabolic adaptation occurs early during the time

  11. Détermination expérimentale des paramètres de Wilson Experimental Dertermination of Wilson Parameters

    Monfort J.-P.

    2006-11-01

    Full Text Available La volabilité relative ait; =(yilxil(Y;lxi des constituants d'un mélange binaire a été mesurée à partir d'un nouveau dispositif expérimental, on reporte les données d'équilibre liquide-vapeur obtenues à 45'C de plusieurs binaires : toluène-acétoni-trile, benzène-acétonitrile et benzène-n-heptane. En ajustant à l'équation de Wilson les données expérimentales de «i/; de ces constituants ainsi que des volatilités relatives des constituants des mélanges d'hydrocarbures-alcools, obtenues dans un précédent travail, on calcule les paramètres énergétiques. La prédiction des points de bulle de mélanges binaires et ternaires obtenue à partir de ces paramètres est satisfaisante. La méthode expérimentale ainsi proposée convient particulièrement pour la sélection des solvant extractifs utilisés dans la distillation extractive. From a new expérimental method, relative volatilities aiti = (yilxil(yilxi for a binary mixture are obtained; vapor-liquid equilibrium data are presented for several systems, i.e. toluene-acétonitrile, benzene-acétonitrile and benzene-n-heptane at 45°C. The two adjustable energyparameters of thé Wilson équation, are obtained by adopting thé «,/j data for these binary mixtures and for alcohol-hydrocarbon mixtures previously studied. Theresults obtained in predicting bubble-pressure data for binary and ternary mixtures are consistent with experimental data.

  12. Socioeconomic and personal behavioral factors affecting children's exposure to VOCs in urban areas in Korea.

    Byun, Hyaejeong; Ryu, Kyongnam; Jang, Kyungjo; Bae, Hyunjoo; Kim, Dongjin; Shin, Hosung; Chu, Jangmin; Yoon, Chungsik

    2010-02-01

    Volatile organic compounds (VOCs) are known to cause adverse health effects. We investigated the relationships between children's VOC exposure and socioeconomic and human activity factors with passive personal samplers, questionnaires, and time-activity diaries (TAD). Statistical analyses were conducted using SAS 9.1, and the results were organized using SigmaPlot 8.0 software. Chemicals such as benzene, toluene, 2-butanone, ethylbenzene, xylene, chloroform, n-hexane, heptane, and some kinds of decanes, which are known to adversely affect public health, were identified in measured samples. These were mainly emitted from outdoor sources (e.g., vehicular traffic) or indoor sources (e.g., household activities such as cooking and cleaning) or both. We concluded that region was the most important socioeconomic factor affecting children's VOC exposure, and the significant compounds were n-hexane (p = 0.006), 1,1,1-trichloroethane (p = 0.001), benzene (p = 0.003), toluene (p = 0.002), ethylbenzene (p = 0.020), m-, p-xylene (p = 0.014), dodecane (p = 0.003), and hexadecane (p = 0.001). Parental education, year of home construction and type of housing were also slightly correlated with personal VOC exposure. Only the concentration of o-xylene (p = 0.027) was significantly affected by the parental education, and the concentrations of benzene (p = 0.030) and 2-butanone (p = 0.049) by the type of housing. Also, tridecane (p = 0.049) and n-hexane (p = 0.033) were significantly associated with the year of home construction. When household activities such as cooking were performed indoors, children's VOC concentrations tended to be higher, especially for n-hexane, chloroform, heptane, toluene (p factors simultaneously, socioeconomic factors such as region had a greater effect on children's VOC exposures than indoor activities. From this study, we can suggest that socioeconomic factors as well as environmental factors should be considered when formulating environmental policy to

  13. In-vitro investigations of the speed of pyrrole formation of 2,5-hexanedione and 2,5-heptanedione with N{alpha}-acetyl-L-lysine as a precondition for a comparative assessment of the neurotoxic potentials of the two {gamma}-diketones; In-vitro-Untersuchungen zur Pyrrolbildungsgeschwindigkeit von 2,5-Hexandion und 2,5-Heptandion mit N{alpha}-Acetyl-L-lysin als Voraussetzung fuer eine vergleichende Abschaetzung der neurotoxischen Potentiale beider {gamma}-Diketone

    Richter, M.F.

    1997-09-01

    N-hexane and n-heptane are important solvents. Chronic exposure to n-hexane causes polyneuropathies, which are attributed to the metabolite 2,5-hexanedione, a {gamma} diketone. As a basis for a comparative assessment of the neurotoxic potentials of 2,5-hexanedione and 2,5-heptanedione, an in-vitro test was developed and used to investigate the speed of pyrrole formation of the two {gamma} diketones in reacting with the {epsilon} amino group of N{alpha}-acetyl L-lysine. The speed of the formation of pyrrole was always directly proportional to the respective reactant concentration. It consequently is subject to a second-order kinetics. As a further result, the pyrrole formation speed of 2,5-heptanedione was found to be only half that of 2,5-hexanedione. The results lead to the conclusion that 2,5-heptanedione poses a smaller risk of developing peripheral neuropathy than 2,5-hexanedione. (orig./MG) [Deutsch] n-Hexan und n-Heptan sind wichtige Loesungsmittel. Chronische Exposition gegenueber n-Hexan ruft Polyneuropathien hervor, die auf den Metaboliten 2,5-Hexandion, ein {gamma}-Diketon, zurueckgefuehrt werden. Als Grundlage fuer eine vergleichende Abschaetzung der neurotoxischen Potentiale von 2,5-Hexandion und 2,5-Heptandion wurde in der vorliegenden Arbeit ein In-vitro-Test entwickelt, mit dem die Pyrrolbildungsgeschwindigkeiten der beiden {gamma}-Diketone mit der {epsilon}-Aminogruppe von N{alpha}-Acetyl-L-Iysin untersucht wurden. Die Pyrrolbildungsgeschwindigkeit war stets direkt proportional zur jeweiligen Reaktantenkonzentration. Somit unterliegt sie einer Kinetik 2. Ordnung. Weiterhin wurde gezeigt, dass die Pyrrolbildungsgeschwindigkeit fuer 2,5-Heptandion nur etwa halb so gross ist wie fuer 2,5-Hexandion. Aus den Ergebnissen wird gefolgert, dass das von 2,5-Heptandion ausgehende Risiko an peripheren Neuropathien zu erkranken geringer ist, als das von 2,5-Hexandion ausgehende. (orig./MG)

  14. Evaluation and optimisation of phenomenological multi-step soot model for spray combustion under diesel engine-like operating conditions

    Pang, Kar Mun; Jangi, Mehdi; Bai, Xue-Song; Schramm, Jesper

    2015-05-01

    In this work, a two-dimensional computational fluid dynamics study is reported of an n-heptane combustion event and the associated soot formation process in a constant volume combustion chamber. The key interest here is to evaluate the sensitivity of the chemical kinetics and submodels of a semi-empirical soot model in predicting the associated events. Numerical computation is performed using an open-source code and a chemistry coordinate mapping approach is used to expedite the calculation. A library consisting of various phenomenological multi-step soot models is constructed and integrated with the spray combustion solver. Prior to the soot modelling, combustion simulations are carried out. Numerical results show that the ignition delay times and lift-off lengths exhibit good agreement with the experimental measurements across a wide range of operating conditions, apart from those in the cases with ambient temperature lower than 850 K. The variation of the soot precursor production with respect to the change of ambient oxygen levels qualitatively agrees with that of the conceptual models when the skeletal n-heptane mechanism is integrated with a reduced pyrene chemistry. Subsequently, a comprehensive sensitivity analysis is carried out to appraise the existing soot formation and oxidation submodels. It is revealed that the soot formation is captured when the surface growth rate is calculated using a square root function of the soot specific surface area and when a pressure-dependent model constant is considered. An optimised soot model is then proposed based on the knowledge gained through this exercise. With the implementation of optimised model, the simulated soot onset and transport phenomena before reaching quasi-steady state agree reasonably well with the experimental observation. Also, variation of spatial soot distribution and soot mass produced at oxygen molar fractions ranging from 10.0 to 21.0% for both low and high density conditions are reproduced.

  15. Aloe vera extract activity on human corneal cells.

    Woźniak, Anna; Paduch, Roman

    2012-02-01

    Ocular diseases are currently an important problem in modern societies. Patients suffer from various ophthalmologic ailments namely, conjunctivitis, dry eye, dacryocystitis or degenerative diseases. Therefore, there is a need to introduce new treatment methods, including medicinal plants usage. Aloe vera [Aloe barbadensis Miller (Liliaceae)] possesses wound-healing properties and shows immunomodulatory, anti-inflammatory or antioxidant activities. NR uptake, MTT, DPPH• reduction, Griess reaction, ELISA and rhodamine-phalloidin staining were used to test toxicity, antiproliferative activity, reactive oxygen species (ROS) reduction, nitric oxide (NO) and cytokine level, and distribution of F-actin in cells, respectively. The present study analyzes the effect of Aloe vera extracts obtained with different solvents on in vitro culture of human 10.014 pRSV-T corneal cells. We found no toxicity of ethanol, ethyl acetate and heptane extracts of Aloe vera on human corneal cells. No ROS reducing activity by heptane extract and trace action by ethanol (only at high concentration 125 µg/ml) extract of Aloe vera was observed. Only ethyl acetate extract expressed distinct free radical scavenging effect. Plant extracts decreased NO production by human corneal cells as compared to untreated controls. The cytokine (IL-1β, IL-6, TNF-α and IL-10) production decreased after the addition of Aloe vera extracts to the culture media. Aloe vera contains multiple pharmacologically active substances which are capable of modulating cellular phenotypes and functions. Aloe vera ethanol and ethyl acetate extracts may be used in eye drops to treat inflammations and other ailments of external parts of the eye such as the cornea.

  16. Synthesis, characterization and pharmacological evaluation of substituted phenoxy acetamide derivatives

    Rani Priyanka

    2015-01-01

    Full Text Available A novel series of 2-(substituted phenoxy-N-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-ylacetamide and N-(2-bromocyclohexyl-2-(substituted phenoxyacetamide derivatives having cyclohexyl nucleus as common in both types were synthesized and assessed for their anti-inflammatory activity by a carrageenan induced rat paw oedema method, analgesic activity by Eddy’s hot plate method and antipyretic activity by brewer’s yeast induced pyrexia method. All the novel derivatives have been synthesized by the reaction of camphor and similar ketone having cyclohexane nucleus (e.g. 2-bromocyclohexanone with ammonium carbonate and formic acid resulting in the formation of aromatic amines (1a-b. These amines on further chloroacetylation with chloroacetylchloride give compounds (2a-b. Compounds (2a-b are converted to 2-(substituted phenoxy-N-(1,7,7-trimethylbicyclo[2.2.1]heptan-2-yl acetamide and N-(2-bromocyclohexyl-2-(substituted phenoxyacetamide derivatives on treatment with substituted phenol. Among the series 3a-f, 3i, 3k, 3l compounds showed significant anti-inflammatory activity as compared to the standard drug diclofenac sodium and also compound 3a-f, 3h, 3j, 3k exhibit significant analgesic activity as compared to the standard drug. Compounds 3a-f and 3k showed antipyretic activity nearly to the standard drug indomethacin. Compounds 3a-f and 3k possess anti-inflammatory, analgesic and antipyretic activities near to the standard.

  17. Refining of fossil resin flotation concentrate from western coal. Final report

    Jensen, G.F.; Miller, J.D.

    1995-02-16

    During the past several years, significant research efforts have been made to develop process technology for the selective flotation of fossil resin from western coals. As a result of these efforts, several new flotation technologies have been developed. Operation of a proof-of-concept continuous flotation circuit showed the selective flotation process to be sufficiently profitable to justify the development of a fossil resin industry. However, little attention has been given to the refining of the fossil resin flotation concentrate although solvent refining is a critical step for the fossil resin to become a marketable product. In view of this situation, DOE funded this two-year project to evaluate the following aspects of the fossil resin refining technology: 1) Characterization of the fossil resin flotation concentrate and its refined products; 2) Kinetics of fossil resin extraction; 3) Effects of operating variables on solvent extraction; 4) Extraction solvents; 5) Proof-of-concept continuous refining tests; and 6) Technical and economic analysis. The results from this research effort have led to the following conclusions: Hexane- or heptane-refined fossil resin has a light-yellow color, a melting point of 140 - 142{degrees}C, a density of 1.034 gram/cm, and good solubility in nonpolar solvents. Among the four solvents evaluated (hexane, heptane, toluene and ethyl acetate), hexane is the most appropriate solvent based on overall technical and economic considerations. Batch extraction tests and kinetic studies suggest that the main interaction between the resin and the solvent is expected to be the forces associated with solvation phenomena. Temperature has the most significant effect on extraction rate. With hexane as the solvent, a recovery of 90% cam be achieved at 50{degrees}C and 10% solids concentration with moderate agitation for 1 hour.

  18. Study on the polarity, solubility, and stacking characteristics of asphaltenes

    Zhang, Long-li

    2014-07-01

    The structure and transformation of fused aromatic ring system in asphaltenes play an important role in the character of asphaltenes, and in step affect the properties of heavy oils. Polarity, solubility and structural characteristics of asphaltenes derived from Tahe atmospheric residue (THAR) and Tuo-826 heavy crude oil (Tuo-826) were analyzed for study of their internal relationship. A fractionation method was used to separate the asphaltenes into four sub-fractions, based on their solubility in the mixed solvent, for the study of different structural and physical-chemical properties, such as polarity, solubility, morphology, stacking characteristics, and mean structural parameters. Transmission electron microscope (TEM) observation can present the intuitive morphology of asphaltene molecules, and shows that the structure of asphaltenes is in local order as well as long range disorder. The analysis results showed that n-heptane asphaltenes of THAR and Tuo-826 had larger dipole moment values, larger fused aromatic ring systems, larger mean number of stacking layers, and less interlayer spacing between stacking layers than the corresponding n-pentane asphaltenes. The sub-fractions that were inclined to precipitate from the mixture of n-heptane and tetrahydrofuran had larger polarity and less solubility. From the first sub-fraction to the fourth sub-fraction, polarity, mean stacking numbers, and average layer size from the TEM images follow a gradual decrease. The structural parameters derived from TEM images could reflect the largest fused aromatic ring system in asphaltene molecule, yet the parameters derived from 1H NMR data reflected the mean message of poly-aromatic ring systems. The structural parameters derived from TEM images were more consistent with the polarity variation of sub-fractions than those derived from 1H NMR data, which indicates that the largest fused aromatic ring system will play a more important role in the stacking characteristics of

  19. Kinetics and mechanistic study of n-alkane hydroisomerization reaction on Pt-doped γ-alumina catalyst

    Abhishek Dhar

    2017-12-01

    Full Text Available The catalysts γ-alumina (GA, the reference catalyst and Pt doped γ-alumina (PGA-s were synthesized using a simple sol-gel technique, in which at first preparation of porous base (GA, then impregnation of platinum salt over the base and finally reduction of platinum in the surface of the support were done. These catalysts prepared in different mole ratios of Pt:Al as 2:1, 1:1 and 1:2 are named as PGA-1, PGA-2 and PGA-3 respectively. The isomerization of n-alkanes (n-hexane, n-heptane and n-octane were investigated over the synthesized catalysts. The 2-methyl pentane (2-MP, 2,2-dimethyl pentane (2,2-DMP and 2,3-dimethyl hexane (2,3-DMH are the major products of respective isomerization of n-hexane, n-heptane and n-octane, besides a small amount of other branched isomers are also produced. The product distribution is comparable to that reported for Pt based other catalysts. The optimal mole ratios of Pt:Al is 1:1 (PGA-2 gives quite good catalytic activity for isomerization of n-alkane. Even through in reusability study, PGA-2 gives better performance than others. We have mainly focused on kinetic study, reaction mechanism behind isomerization and calculated the order of reactions and activation energies of the isomerization reactions in the present work. Keywords: Isomerization, n-alkanes, Catalyst, Reaction mechanism, Kinetics study, Activation energy

  20. Computational Analysis of Spray Jet Flames

    Jain, Utsav

    droplet parameters needed, a rigorous parametric study is conducted for five different parameters in both physical as well as mixing variable space. The parametric study is conducted for a counterflow setup with n-heptane and inert nitrogen on the fuel side and oxygen with inert nitrogen on the oxidizer side. The computational setup (the temperature and velocity field) is validated against the experimental data from the Yale heptane counterflow flame. The five parameters that are investigated are: aerodynamic strain rate, initial droplet diameter, number of fuel droplets, droplet velocity slip ratio and pre-vaporization ratio. It is not the first time such a study has been accomplished but not a lot of research has been done for heavier fuels such as n-heptane (a very crucial reference fuel for the octane ratings in various applications). Also parameters such as droplet slip ratio and pre-vaporization ratio have not been prudently studied in the past. It is observed that though the slip ratio is not very significant in spray flamelet characterization, the pre-vaporization ratio is important to study and has an interesting influence on spray flamelet structure. In future, based on the current parametric study, the laminar spray flamelet library can be generated which will eventually be integrated to predict turbulent spray flames.

  1. GDI fuel sprays of light naphtha, PRF95 and gasoline using a piezoelectric injector under different ambient pressures

    Wu, Zengyang

    2018-03-20

    This study investigates fuel sprays of light naphtha (LN), primary reference fuel (PRF) and gasoline under different ambient pressures with an outwardly opening piezo gasoline direct injection (GDI) fuel injector. The tested gasoline fuel (regular grade with up to 10% ethanol, E10) was obtained by mixing fuels with AKI (the average of the research octane number (RON) and the motor octane number (MON)) of 87 from three local gas stations. Primary reference fuel (PRF) is commonly used as gasoline surrogate fuel and is blended by iso-octane and n-heptane. PRF95 is the blend of 95% iso-octane and 5% n-heptane by volume. LN fuel was provided by Saudi Aramco Oil Company. Five different ambient pressure conditions varied from 1 bar to 10 bar were tested. The spray was visualized by applying a Mie-scattering technique and a high-speed camera was employed to capture the spray images. The spray structure, spray angle, spray penetration length and spray front fluctuation were analyzed and compared among three fuels. Spray images show that a clear filamentary hollow-cone spray structure is formed for all three fuels at atmospheric conditions, and toroidal recirculation vortexes are observed at the downstream spray edges. A higher ambient pressure leads to a stronger vortex located closer to the injector outlet. Generally speaking, larger spray angles are found under higher ambient pressure conditions for all three fuels. Gasoline fuel always has the largest spray angle for each ambient pressure, while PRF95 has the smallest at most time. For each fuel, the spray front penetration length and spray front penetration velocity decrease with increasing ambient pressure. LN, PRF95 and gasoline show similar penetration length and velocity under the tested conditions. A two-stage spray front fluctuation pattern is observed for all three fuels. Stage one begins from the start of the injection and ends at 450–500 μs after the start of the injection trigger (ASOIT) with a slow

  2. A blending rule for octane numbers of PRFs and TPRFs with ethanol

    AlRamadan, Abdullah S.

    2016-04-12

    Ethanol is widely used as an octane booster in commercial gasoline fuels. Its oxygenated nature aids in reducing harmful emissions such as nitric oxides (NOx), soot and unburned hydrocarbons (HC). However, the non-linear octane response of ethanol blending with gasoline fuels is not completely understood because of the unknown intermolecular interactions in such blends. In general, when ethanol is blended with gasoline, the Research Octane Number (RON) and the Motor Octane Number (MON) non-linearly increase (synergistic) or decrease (antagonistic), and the non-linearity depends on the composition of the base gasoline. The complexity of commercial gasoline, comprising of hundreds of different components, makes it challenging to understand ethanol-gasoline synergistic/antagonistic blending effects. Understanding ethanol blending effects with simpler gasoline surrogates blends may enable a better understanding of ethanol blending with complex multi-component gasoline fuels. This study presents a blending rule to predict the octane numbers (ON) of ethanol/primary reference fuel (PRF; mixtures of iso-octane and n-heptane) and ethanol/toluene primary reference fuel (TPRF; mixtures of toluene, iso-octane and n-heptane) mixtures using the data available in literature and new data. The ON of ethanol blends with PRF-40, -50, and -60 were measured and compared with those from literature. Additional experimental data were collected to validate the developed model for ethanol blends of three different TPRFs having the same RON but different MON (i.e., different toluene contents). The three tested TPRF mixtures have octane ratings of RON 60.0/MON 58.0 (toluene 10.2 vol%), RON 60.0/MON 56.3 (toluene 19.8 vol%), and RON 60.0/MON 53.2 (toluene 40.2 vol%). The octane prediction model consists of linear and non-linear by mole regions. The transition point between the linear and non-linear regions is a function of the RON and MON of the base PRF and TPRF mixture. The non-linear by

  3. GDI fuel sprays of light naphtha, PRF95 and gasoline using a piezoelectric injector under different ambient pressures

    Wu, Zengyang; Wang, Libing; Badra, Jihad A.; Roberts, William L.; Fang, Tiegang

    2018-01-01

    This study investigates fuel sprays of light naphtha (LN), primary reference fuel (PRF) and gasoline under different ambient pressures with an outwardly opening piezo gasoline direct injection (GDI) fuel injector. The tested gasoline fuel (regular grade with up to 10% ethanol, E10) was obtained by mixing fuels with AKI (the average of the research octane number (RON) and the motor octane number (MON)) of 87 from three local gas stations. Primary reference fuel (PRF) is commonly used as gasoline surrogate fuel and is blended by iso-octane and n-heptane. PRF95 is the blend of 95% iso-octane and 5% n-heptane by volume. LN fuel was provided by Saudi Aramco Oil Company. Five different ambient pressure conditions varied from 1 bar to 10 bar were tested. The spray was visualized by applying a Mie-scattering technique and a high-speed camera was employed to capture the spray images. The spray structure, spray angle, spray penetration length and spray front fluctuation were analyzed and compared among three fuels. Spray images show that a clear filamentary hollow-cone spray structure is formed for all three fuels at atmospheric conditions, and toroidal recirculation vortexes are observed at the downstream spray edges. A higher ambient pressure leads to a stronger vortex located closer to the injector outlet. Generally speaking, larger spray angles are found under higher ambient pressure conditions for all three fuels. Gasoline fuel always has the largest spray angle for each ambient pressure, while PRF95 has the smallest at most time. For each fuel, the spray front penetration length and spray front penetration velocity decrease with increasing ambient pressure. LN, PRF95 and gasoline show similar penetration length and velocity under the tested conditions. A two-stage spray front fluctuation pattern is observed for all three fuels. Stage one begins from the start of the injection and ends at 450–500 μs after the start of the injection trigger (ASOIT) with a slow

  4. A Background of a Volatile Plant Compound Alters Neural and Behavioral Responses to the Sex Pheromone Blend in a Moth.

    Dupuy, Fabienne; Rouyar, Angéla; Deisig, Nina; Bourgeois, Thomas; Limousin, Denis; Wycke, Marie-Anne; Anton, Sylvia; Renou, Michel

    2017-01-01

    . One percent heptanal and linalool, in addition to the masking effect, caused a clear delay in responses of MGC neurons to the sex pheromone. Upwind flight toward the pheromone in a wind tunnel was also delayed but otherwise not altered by different doses of heptanal.

  5. Phase equilibria of didecyldimethylammonium nitrate ionic liquid with water and organic solvents

    Domanska, Urszula; Lugowska, Katarzyna; Pernak, Juliusz

    2007-01-01

    The phase diagrams for binary mixtures of an ammonium ionic liquid, didecyldimethylammonium nitrate, [DDA][NO 3 ], with: alcohols (propan-1-ol, butan-1-ol, octan-1-ol, and decan-1-ol): hydrocarbons (toluene, propylbenzene, hexane, and hexadecane) and with water were determined in our laboratory. The phase equilibria were measured by a dynamic method from T 220 K to either the melting point of the ionic liquid, or to the boiling point of the solvent. A simple liquidus curve in a eutectic system was observed for [DDA][NO 3 ] with: alcohols (propan-1-ol, butan-1-ol, and octan-1-ol); aromatic hydrocarbons (toluene and propylbenzene) and with water. (Solid + liquid) equilibria with immiscibility in the liquid phase were detected with the aliphatic hydrocarbons heptane and hexadecane and with decan-1-ol. (Liquid + liquid) equilibria for the system [DDA][NO 3 ] with hexadecane was observed for the whole mole fraction range of the ionic liquid. The observation of the upper critical solution temperature in binary mixtures of ([DDA][NO 3 ] + decan-1-ol, heptane, or hexadecane) was limited by the boiling temperature of the solvent. Characterisation and purity of the compounds were determined by elemental analysis, water content (Fisher method) and differential scanning microcalorimetry (d.s.c.) analysis. The d.s.c. method of analysis was used to determine melting temperatures and enthalpies of fusion. The thermal stability of the ionic liquid was resolved by the thermogravimetric technique-differential thermal analysis (TG-DTA) technique over a wide temperature range from (200 to 780) K. The thermal decomposition temperature of 50% of the sample was greater than 500 K. The (solid + liquid) phase equilibria, curves were correlated by means of different G Ex models utilizing parameters derived from the (solid + liquid) equilibrium. The root-mean-square deviations of the solubility temperatures for all calculated data are dependent upon the particular system and the particular

  6. Residency of rhenium and osmium in a heavy crude oil

    DiMarzio, Jenna M.; Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.

    2018-01-01

    Rhenium-osmium (Re-Os) isotope geochemistry is an emerging tool for the study of oil formation and migration processes, and a new technology for petroleum exploration. Little is known, however, about the residency of Re and Os within asphaltene and maltene sub-fractions of crude oil. This information is crucial for understanding the 187Re-187Os radiometric clock held in petroleum systems and for interpreting geochronology for key processes such as oil formation, migration, and biodegradation. In this study, a heavy crude oil was separated into soluble (maltene, MALT) and insoluble (asphaltene, ASPH) fractions using n-heptane as the asphaltene-precipitating agent. The asphaltenes were separated sequentially into sub-fractions using two different solvent pairs (heptane-dichloromethane and acetone-toluene), and the bulk maltenes were separated into saturate, aromatic, and resin (SAR) fractions using open column chromatography. Each asphaltene and maltene sub-fraction was analyzed for Re and Os. The asphaltene sub-fractions and the bulk ASPH, MALT, and crude oil were analyzed for a suite of trace metals by ICP-MS. Our results show that Re and Os concentrations co-vary between the asphaltene sub-fractions, and that both elements are found mostly in the more polar and aromatic sub-fractions. Significant Re and Os are also present in the aromatic and resin fractions of the maltenes. However, each asphaltene and maltene sub-fraction has a distinct isotopic composition, and sub-fractions are not isochronous. This suggests that asphaltene sub-fractionation separates Re-Os complexes to the point where the isotopic integrity of the geochronometer is compromised. The mobility of individual Re and Os isotopes and the decoupling possibilities between radiogenic 187Os produced from 187Re remain elusive, but their recognition in this study is a critical first step. Re and Os correlate strongly with Mo and Cd in the asphaltene sub-fractions, suggesting that these metals occupy

  7. An analytical system for the measurement of stable hydrogen isotopes in ambient volatile organic compounds

    Meisehen, T.; Bühler, F.; Koppmann, R.; Krebsbach, M.

    2015-10-01

    Stable isotope measurements in atmospheric volatile organic compounds (VOCs) are an excellent tool to analyse chemical and dynamical processes in the atmosphere. While up to now isotope studies of VOCs in ambient air have mainly focussed on carbon isotopes, we herein present a new measurement system to investigate hydrogen isotope ratios in atmospheric VOCs. This system, consisting of a gas chromatography pyrolysis isotope ratio mass spectrometer (GC-P-IRMS) and a pre-concentration system, was thoroughly characterised using a VOC test mixture. A precision of better than 9 ‰ (in δ 2H) is achieved for n-pentane, 2-methyl-1,3-butadiene (isoprene), n-heptane, 4-methyl-pentane-2-one (4-methyl-2-pentanone), methylbenzene (toluene), n-octane, ethylbenzene, m/p-xylene and 1,2,4-trimethylbenzene. A comparison with independent measurements via elemental analysis shows an accuracy of better than 9 ‰ for n-pentane, n-heptane, 4-methyl-2-pentanone, toluene and n-octane. Above a minimum required pre-concentrated compound mass the obtained δ 2H values are constant within the standard deviations. In addition, a remarkable influence of the pyrolysis process on the isotope ratios is found and discussed. Reliable measurements are only possible if the ceramic tube used for the pyrolysis is sufficiently conditioned, i.e. the inner surface is covered with a carbon layer. It is essential to verify this conditioning regularly and to renew it if required. Furthermore, influences of a necessary H3+ correction and the pyrolysis temperature on the isotope ratios are discussed. Finally, the applicability to measure hydrogen isotope ratios in VOCs at ambient levels is demonstrated with measurements of outside air on 5 different days in February and March 2015. The measured hydrogen isotope ratios range from -136 to -105 ‰ forn-pentane, from -86 to -63 ‰ for toluene, from -39 to -15 ‰ for ethylbenzene, from -99 to -68 ‰ for m/p-xylene and from -45 to -34 ‰ for o-xylene.

  8. Structural Study of Asphaltenes from Iranian Heavy Crude Oil

    Davarpanah L.

    2015-11-01

    Full Text Available In the present study, asphaltene precipitation from Iranian heavy crude oil (Persian Gulf off-shore was performed using n-pentane (n-C5 and n-heptane (n-C7 as light alkane precipitants. Several analytical techniques, each following different principles, were then used to structurally characterize the precipitated asphaltenes. The yield of asphaltene obtained using n-pentane precipitant was higher than asphaltene precipitated with the use of n-heptane. The asphaltene removal affected the n-C5 and n-C7 maltene fractions at temperatures below 204°C, as shown by the data obtained through the simulated distillation technique. Viscosity of heavy oil is influenced by the asphaltene content and behavior. The viscosity dependence of the test heavy oil on the shear rate applied was determined and the flow was low at y. above 25 s-1 . The reconstituted heavy oil samples were prepared by adding different amounts of asphaltenes to the maltenes (deasphalted heavy oil and asphaltene effects were more pronounced at the low temperature of 25°C as compared with those at the higher temperatures. According to the power law model used in this study the flowability of the test heavy oil exhibited a pseudoplastic character. Structural results obtained from Fourier Transform InfraRed (FTIR spectroscopy showed the presence of the different functional groups in the precipitated asphaltenes. For instance, the presence of different hydrocarbons (aliphatic, aromatic and alicyclic based on their characteristics in the FTIR spectra was confirmed. Resins are effective dispersants, and removal of this fraction from the crude oil is disturbing to the colloidal nature of heavy oil; asphaltene flocculation and precipitation eventually occur. Appearance of pores in the Scanning Electron Microscopy (SEM images was used as an indicator of the resin detachment. With the use of 1H and 13C Nuclear Magnetic Resonance (NMR spectroscopy, two important structural parameters of the

  9. Three column intermittent simulated moving bed chromatography: 3. Cascade operation for center-cut separations.

    Jermann, Simon; Meijssen, Mattheus; Mazzotti, Marco

    2015-01-23

    A general design methodology for chromatographic three fraction separation by application of the three column intermittent simulated moving bed (3C-ISMB) cascade is proposed and experimentally validated by studying the purification of an intermediately retained stereoisomer of nadolol, from an equimolar mixture of its four stereoisomers. The theoretical part shows that the 3C-ISMB cascade can be easily designed by applying Triangle Theory. Moreover, a re-scaling approach for the second stage is proposed so as to account for the fact that the feed flow rates to stage 2 are generally higher as compared to stage 1 due to dilution in the latter. Scaling the columns of the second stage accordingly enables to run both stages under optimal conditions with respect to switching time and step ratio, which is an important advantage as compared to integrated ternary processes. The experimental part starts with studying the linear adsorption behavior of nadolol in heptane/ethanol/DEA on Chiralpak AD for varying ratios of heptane and ethanol. Based on that, a solvent composition of Hept/EtOH/DEA 30/70/0.3 (v/v/v) is selected and the competitive multi-component Langmuir isotherm of the quaternary mixture is determined by frontal analysis. The resulting isotherm parameters are used to design several first stage experiments aiming at removal of the most retained component. The resulting ternary intermediate product is reprocessed in several second stage experiments studying various configurations. Finally, the dilution of the intermediate product with Hept/DEA yielding a solvent composition of Hept/EtOH/DEA 60/40/0.3 (v/v/v) is examined showing that the resulting increase in retention is beneficial for final product purities. Moreover, the reduction in viscosity compensates for the dilution as it enables higher flow rates. Dilution of the intermediate product is hence the best option, yielding highest overall cascade productivity (2.10gl(-1)h(-1)) and highest product purity (97

  10. Shock tube measurements of the rate constants for seven large alkanes+OH

    Badra, Jihad

    2015-01-01

    Reaction rate constants for seven large alkanes + hydroxyl (OH) radicals were measured behind reflected shock waves using OH laser absorption. The alkanes, n-hexane, 2-methyl-pentane, 3-methyl-pentane, 2,2-dimethyl-butane, 2,3-dimethyl-butane, 2-methyl-heptane, and 4-methyl-heptane, were selected to investigate the rates of site-specific H-abstraction by OH at secondary and tertiary carbons. Hydroxyl radicals were monitored using narrow-line-width ring-dye laser absorption of the R1(5) transition of the OH spectrum near 306.7 nm. The high sensitivity of the diagnostic enabled the use of low reactant concentrations and pseudo-first-order kinetics. Rate constants were measured at temperatures ranging from 880 K to 1440 K and pressures near 1.5 atm. High-temperature measurements of the rate constants for OH + n-hexane and OH + 2,2-dimethyl-butane are in agreement with earlier studies, and the rate constants of the five other alkanes with OH, we believe, are the first direct measurements at combustion temperatures. Using these measurements and the site-specific H-abstraction measurements of Sivaramakrishnan and Michael (2009) [1,2], general expressions for three secondary and two tertiary abstraction rates were determined as follows (the subscripts indicate the number of carbon atoms bonded to the next-nearest-neighbor carbon): S20=1.58×10-11exp(-1550K/T)cm3molecule-1s-1(887-1327K)S30=2.37×10-11exp(-1850K/T)cm3molecule-1s-1(887-1327K)S21=4.5×10-12exp(-793.7K/T)cm3molecule-1s-1(833-1440K)T100=2.85×10-11exp(-1138.3K/T)cm3molecule-1s-1(878-1375K)T101=7.16×10-12exp(-993K/T)cm3molecule-1s-1(883-1362K) © 2014 The Combustion Institute.

  11. Enantiomeric metabolic interactions and stereoselective human methadone metabolism.

    Totah, Rheem A; Allen, Kyle E; Sheffels, Pamela; Whittington, Dale; Kharasch, Evan D

    2007-04-01

    Methadone is administered as a racemate, although opioid activity resides in the R-enantiomer. Methadone disposition is stereoselective, with considerable unexplained variability in clearance and plasma R/S ratios. N-Demethylation of methadone in vitro is predominantly mediated by cytochrome P450 CYP3A4 and CYP2B6 and somewhat by CYP2C19. This investigation evaluated stereoselectivity, models, and kinetic parameters for methadone N-demethylation by recombinant CYP2B6, CYP3A4, and CYP2C19, and the potential for interactions between enantiomers during racemate metabolism. CYP2B6 metabolism was stereoselective. CYP2C19 was less active, and stereoselectivity was opposite that for CYP2B6. CYP3A4 was not stereoselective. With all three isoforms, enantiomer N-dealkylation rates in the racemate were lower than those of (R)-(6-dimethyamino-4,4-diphenyl-heptan-3-one) hydrochloride (R-methadone) or (S)-(6-dimethyamino-4,4-diphenyl-heptan-3-one) hydrochloride (S-methadone) alone, suggesting an enantiomeric interaction and mutual metabolic inhibition. For CYP2B6, the interaction between enantiomers was stereoselective, with S-methadone as a more potent inhibitor of R-methadone N-demethylation than R-of S-methadone. In contrast, enantiomer interactions were not stereoselective with CYP2C19 or CYP3A4. For all three cytochromes P450, methadone N-demethylation was best described by two-site enzyme models with competitive inhibition. There were minor model differences between cytochromes P450 to account for stereoselectivity of metabolism and enantiomeric interactions. Changes in plasma R/S methadone ratios observed after rifampin or troleandomycin pretreatment in humans in vivo were successfully predicted by CYP2B6- but not CYP3A4-catalyzed methadone N-demethylation. CYP2B6 is a predominant catalyst of stereoselective methadone metabolism in vitro. In vivo, CYP2B6 may be a major determinant of methadone metabolism and disposition, and CYP2B6 activity and stereoselective metabolic

  12. Predicting the oral uptake efficiency of chemicals in mammals: Combining the hydrophilic and lipophilic range

    O' Connor, Isabel A., E-mail: i.oconnor@science.ru.nl [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Huijbregts, Mark A.J., E-mail: m.huijbregts@science.ru.nl [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Ragas, Ad M.J., E-mail: a.ragas@science.ru.nl [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands); Open University, School of Science, P.O. Box 2960,6401 DL Heerlen (Netherlands); Hendriks, A. Jan, E-mail: a.j.hendriks@science.ru.nl [Radboud University Nijmegen, Institute for Water and Wetland Research, Department of Environmental Science, P.O. Box 9010, NL-6500 GL, Nijmegen (Netherlands)

    2013-01-01

    Environmental risk assessment requires models for estimating the bioaccumulation of untested compounds. So far, bioaccumulation models have focused on lipophilic compounds, and only a few have included hydrophilic compounds. Our aim was to extend an existing bioaccumulation model to estimate the oral uptake efficiency of pollutants in mammals for compounds over a wide K{sub ow} range with an emphasis on hydrophilic compounds, i.e. compounds in the lower K{sub ow} range. Usually, most models use octanol as a single surrogate for the membrane and thus neglect the bilayer structure of the membrane. However, compounds with polar groups can have different affinities for the different membrane regions. Therefore, an existing bioaccumulation model was extended by dividing the diffusion resistance through the membrane into an outer and inner membrane resistance, where the solvents octanol and heptane were used as surrogates for these membrane regions, respectively. The model was calibrated with uptake efficiencies of environmental pollutants measured in different mammals during feeding studies combined with human oral uptake efficiencies of pharmaceuticals. The new model estimated the uptake efficiency of neutral (RMSE = 14.6) and dissociating (RMSE = 19.5) compounds with logK{sub ow} ranging from − 10 to + 8. The inclusion of the K{sub hw} improved uptake estimation for 33% of the hydrophilic compounds (logK{sub ow} < 0) (r{sup 2} = 0.51, RMSE = 22.8) compared with the model based on K{sub ow} only (r{sup 2} = 0.05, RMSE = 34.9), while hydrophobic compounds (logK{sub ow} > 0) were estimated equally by both model versions with RMSE = 15.2 (K{sub ow} and K{sub hw}) and RMSE = 15.7 (K{sub ow} only). The model can be used to estimate the oral uptake efficiency for both hydrophilic and hydrophobic compounds. -- Highlights: ► A mechanistic model was developed to estimate oral uptake efficiency. ► Model covers wide logK{sub ow} range (- 10 to + 8) and several mammalian

  13. Kinetics and thermodynamics of small molecule binding to pincer-PCP rhodium(I) complexes

    Doherty, Mark D.

    2013-04-15

    The kinetics and thermodynamics of the binding of several small molecules, L (L = N2, H2, D2, and C2H 4), to the coordinatively unsaturated pincer-PCP rhodium(I) complexes Rh[tBu2PCH2(C6H3)CH 2PtBu2] (1) and Rh[tBu 2P(CH2)2(CH)(CH2)2P tBu2] (2) in organic solvents (n-heptane, toluene, THF, and cyclohexane-d12) have been investigated by a combination of kinetic flash photolysis methods, NMR equilibrium studies, and density functional theory (DFT) calculations. Using various gas mixtures and monitoring by NMR until equilibrium was established, the relative free energies of binding of N2, H2, and C2H4 in cyclohexane-d12 were found to increase in the order C 2H4 < N2 < H2. Time-resolved infrared (TRIR) and UV-vis transient absorption spectroscopy revealed that 355 nm excitation of 1-L and 2-L results in the photoejection of ligand L. The subsequent mechanism of binding of L to 1 and 2 to regenerate 1-L and 2-L is determined by the structure of the PCP ligand framework and the nature of the solvent. In both cases, the primary transient is a long-lived, unsolvated species (τ = 50-800 ns, depending on L and its concentration in solution). For 2, this so-called less-reactive form (LRF) is in equilibrium with a more-reactive form (MRF), which reacts with L at diffusion-controlled rates to regenerate 2-L. These two intermediates are proposed to be different conformers of the three-coordinate (PCP)Rh fragment. For 1, a similar mechanism is proposed to occur, but the LRF to MRF step is irreversible. In addition, a parallel reaction pathway was observed that involves the direct reaction of the LRF of 1 with L, with second-order rate constants that vary by almost 3 orders of magnitude, depending on the nature of L (in n-heptane, k = 6.7 × 10 5 M-1 s-1 for L = C2H4; 4.0 × 106 M-1 s-1 for L = N2; 5.5 × 108 M-1 s-1 for L = H2). Experiments in the more coordinating solvent, THF, revealed the binding of THF to 1 to generate 1-THF, and its subsequent reaction with L, as a

  14. Combustion Kinetic Studies of Gasolines and Surrogates

    Javed, Tamour

    2016-11-01

    Future thrusts for gasoline engine development can be broadly summarized into two categories: (i) efficiency improvements in conventional spark ignition engines, and (ii) development of advance compression ignition (ACI) concepts. Efficiency improvements in conventional spark ignition engines requires downsizing (and turbocharging) which may be achieved by using high octane gasolines, whereas, low octane gasolines fuels are anticipated for ACI concepts. The current work provides the essential combustion kinetic data, targeting both thrusts, that is needed to develop high fidelity gasoline surrogate mechanisms and surrogate complexity guidelines. Ignition delay times of a wide range of certified gasolines and surrogates are reported here. These measurements were performed in shock tubes and rapid compression machines over a wide range of experimental conditions (650 – 1250 K, 10 – 40 bar) relevant to internal combustion engines. Using the measured the data and chemical kinetic analyses, the surrogate complexity requirements for these gasolines in homogeneous environments are specified. For the discussions presented here, gasolines are classified into three categories: (i)\\tLow octane gasolines including Saudi Aramco’s light naphtha fuel (anti-knock index, AKI = (RON + MON)/2 = 64; Sensitivity (S) = RON – MON = 1), certified FACE (Fuels for Advanced Combustion Engines) gasoline I and J (AKI ~ 70, S = 0.7 and 3 respectively), and their Primary Reference Fuels (PRF, mixtures of n-heptane and iso-octane) and multi-component surrogates. (ii)\\t Mid octane gasolines including FACE A and C (AKI ~ 84, S ~ 0 and 1 respectively) and their PRF surrogates. Laser absorption measurements of intermediate and product species formed during gasoline/surrogate oxidation are also reported. (iii)\\t A wide range of n-heptane/iso-octane/toluene (TPRF) blends to adequately represent the octane and sensitivity requirements of high octane gasolines including FACE gasoline F and G

  15. Chemical Kinetic Insights into the Octane Number and Octane Sensitivity of Gasoline Surrogate Mixtures

    Singh, Eshan

    2017-02-01

    Gasoline octane number is a significant empirical parameter for the optimization and development of internal combustion engines capable of resisting knock. Although extensive databases and blending rules to estimate the octane numbers of mixtures have been developed and the effects of molecular structure on autoignition properties are somewhat understood, a comprehensive theoretical chemistry-based foundation for blending effects of fuels on engine operations is still to be developed. In this study, we present models that correlate the research octane number (RON) and motor octane number (MON) with simulated homogeneous gas-phase ignition delay times of stoichiometric fuel/air mixtures. These correlations attempt to bridge the gap between the fundamental autoignition behavior of the fuel (e.g., its chemistry and how reactivity changes with temperature and pressure) and engine properties such as its knocking behavior in a cooperative fuels research (CFR) engine. The study encompasses a total of 79 hydrocarbon gasoline surrogate mixtures including 11 primary reference fuels (PRF), 43 toluene primary reference fuels (TPRF), and 19 multicomponent (MC) surrogate mixtures. In addition to TPRF mixture components of iso-octane/n-heptane/toluene, MC mixtures, including n-heptane, iso-octane, toluene, 1-hexene, and 1,2,4-trimethylbenzene, were blended and tested to mimic real gasoline sensitivity. ASTM testing protocols D-2699 and D-2700 were used to measure the RON and MON of the MC mixtures in a CFR engine, while the PRF and TPRF mixtures’ octane ratings were obtained from the literature. The mixtures cover a RON range of 0–100, with the majority being in the 70–100 range. A parametric simulation study across a temperature range of 650–950 K and pressure range of 15–50 bar was carried out in a constant-volume homogeneous batch reactor to calculate chemical kinetic ignition delay times. Regression tools were utilized to find the conditions at which RON and MON

  16. Kinetics and thermodynamics of small molecule binding to pincer-PCP rhodium(I) complexes

    Doherty, Mark D.; Grills, David C.; Huang, Kuo-Wei; Muckerman, James T.; Polyansky, Dmitry E.; Van Eldik, Rudi V.; Fujita, Etsuko

    2013-01-01

    The kinetics and thermodynamics of the binding of several small molecules, L (L = N2, H2, D2, and C2H 4), to the coordinatively unsaturated pincer-PCP rhodium(I) complexes Rh[tBu2PCH2(C6H3)CH 2PtBu2] (1) and Rh[tBu 2P(CH2)2(CH)(CH2)2P tBu2] (2) in organic solvents (n-heptane, toluene, THF, and cyclohexane-d12) have been investigated by a combination of kinetic flash photolysis methods, NMR equilibrium studies, and density functional theory (DFT) calculations. Using various gas mixtures and monitoring by NMR until equilibrium was established, the relative free energies of binding of N2, H2, and C2H4 in cyclohexane-d12 were found to increase in the order C 2H4 < N2 < H2. Time-resolved infrared (TRIR) and UV-vis transient absorption spectroscopy revealed that 355 nm excitation of 1-L and 2-L results in the photoejection of ligand L. The subsequent mechanism of binding of L to 1 and 2 to regenerate 1-L and 2-L is determined by the structure of the PCP ligand framework and the nature of the solvent. In both cases, the primary transient is a long-lived, unsolvated species (τ = 50-800 ns, depending on L and its concentration in solution). For 2, this so-called less-reactive form (LRF) is in equilibrium with a more-reactive form (MRF), which reacts with L at diffusion-controlled rates to regenerate 2-L. These two intermediates are proposed to be different conformers of the three-coordinate (PCP)Rh fragment. For 1, a similar mechanism is proposed to occur, but the LRF to MRF step is irreversible. In addition, a parallel reaction pathway was observed that involves the direct reaction of the LRF of 1 with L, with second-order rate constants that vary by almost 3 orders of magnitude, depending on the nature of L (in n-heptane, k = 6.7 × 10 5 M-1 s-1 for L = C2H4; 4.0 × 106 M-1 s-1 for L = N2; 5.5 × 108 M-1 s-1 for L = H2). Experiments in the more coordinating solvent, THF, revealed the binding of THF to 1 to generate 1-THF, and its subsequent reaction with L, as a

  17. Modeling of Diesel Fuel Spray Formation and Combustion in OpenFOAM

    Koesters, Anne

    2012-07-01

    Laboratories. The next step was to update the code with a model of the turbulence-chemistry interaction. The volume reactor fraction model (VRFM), a novel partially stirred reactor (PaSR) model, has been implemented in OpenFOAMr. The model defines a reactor fraction based on the mixture fraction, the chemical progress variable, and their variances instead of defining mixing and chemical time scales. The chemistry is described by a reduced n-heptane mechanism with 36 species involved in 81 reactions. The effect of exhaust gas recirculation (EGR) on n-heptane sprays for Diesel enginelike conditions was studied with the VRFM and results obtained from the calculations are compared to experimental data from the Engine Combustion Network.

  18. PENGAMBILAN FRAKSI RINGAN PRODUK HASIL PIROLISIS LIMBAH PLASTIK JENIS POLIPROPILENE (PP DENGAN METODE DESTILASI FRAKSIONASI BUBBLE CAP

    Ramli Thahir

    2014-10-01

    Full Text Available Increased utilization of plastics each year due to various advantages such as low production cost, light weight, are insulators that are used in various fields of industry and households. Plastic Polypropilene type most widely used in daily life because it has good mechanical properties with low density, heat resistance and moisture, and has good dimensional stability. Besides the benefit impacts can damage environments as difficult to decompose in the soil and can cause flooding when above ground level. Along with the impact of fuel demand is increasing while the fuel sources we use non-renewable (Non Reversible, so this study aims to utilize plastic waste into fuel by specifying and analyzing the quality of fuel products from plastic types of polypropilene. Research methods 200 grams of plastic types polypropropilene cleaned and put in a reactor capacity of 7.5 liters and made the process of pyrolysis, pyrolysis results of 184.20 grams of distilled fractionation Bubble Cap with steam temperature variations: 48-70; 70-90; 90-110; 110-130; 130-150; 150-170; 170-190; 190-210; 210-230; Yeald 230-245oC with a total of 73.80% consisting of gasoline fraction has a content of 85.26% and 14.74% kerosene content. and the results of the analysis, 150C Density (kg / m3: 732.8; 15oC Viscosity (cSt: 0.575; Octane numbers (RON and MON: 97.1 87.8; RVP: 46; Existent Gum: 5; Copper Corrosion class I results of GC-MS analysis results of pyrolysis dominant for 5-methyl-1-heptane: 47.420% and distilled 5-methyl-1-heptane: 48.58%. Results of the analysis concluded that fuel produced from polypropilene plastic pyrolysis process leading to the type of gasoline is 88 according to the decree of Directorate General of Oil and Gas K / 72 / DJM / 1999. Gasoline can not be used directly because it has not met the standards Existent Gum and boiling points that influence the early start the engine or may cause changes in the properties of the fuel.

  19. Volatile compounds of Domiati cheese made from buffaloe's milk with different fat content.

    El-Mageed, Magda A. Abd

    1997-12-01

    Full Text Available Buffaloe's milk was manufactured to Domiati cheese with different fat content in the cheese milk (1%, 3.5% and 7%. Results obtained during the ripening period revealed that the low fat cheese (Karish is not able to long period storage, while half cream cheese had a good quality and flavour along the ripening period. The full cream cheese did not exceed the first month of ripening, then it deteriorated. The main components found were acrolein (propenal, heptanal, acetone, butan-2 one, ethanol, butan-2 ol, 2-methylpropan- 1-ol, 3-methyl butan-1-ol, ethyl propionate, propyl propionate, pentane and octane. Methyl mercaptan, methyl thiopropionate, and dimethyl trisulfide together with propyl butyrate, were existed in the samples which are characterized as bad cheese samples. Most of the previous compounds were developed after 1 month of ripening period.

    La leche de búfalo fue procesada para obtener queso Domiati con diferente contenido graso en la cuajada (1%, 3.5% y 7%. Los resultados obtenidos durante el período de maduración revelaron que el queso con bajo contenido en grasa (Karish no permite un largo período de almacenamiento, mientras que el queso con un contenido medio en grasa tuvo una buena calidad y flavor durante el período de maduración. El queso con alto contenido graso no duró más que el primer mes de maduración, deteriorándose posteriormente. Los principales componentes encontrados fueron acroleína (propenal, heptanal, acetona, butan-2-ona, etanol, butan-2-ol, 2- metil-propan-1-ol, 3 metil butan-1-ol, propionato de etilo, propionate de propilo, pentano y octano. Metil mercaptol, tiopropionato de metilo y trisulfuro de dimetilo Junto con butirato de propilo se encontraron en muestras que fueron caracterizadas como muestras de quesos malos. La mayoría de los compuestos anteriores se produjeron después de un mes de período de maduración.

  20. Film self-assembly properties of vacuum residua from crude oil and correlation to the stability of water/crude oil emulsions[Supercritical fluid extraction and fractional technology (SFEF)

    Peng, Bo

    2005-07-01

    In this thesis, SFEF technology has been used to obtain a fine separation of vacuum residua. Three kinds of vacuum residua from Iranian Heavy Crude Oil, Iranian Light Crude Oil and Daqing Crude Oil have been separated respectively into three series narrow cut fractions as a function of the average molecular weight. And their molecular parameters have been characterized by Vapour Pressure Osmometry(VPO) system, Ultraviolet(UV) spectroscopy, Infrared(IR) spectroscopy as well as by elemental analysis. The various fractions of vacuum residua have been added to an oil/water model system. The oil phase used was pure heptane, pure toluene, a mixture of heptane and toluene etc. Various properties of the interfacial film have been studied such as the self-assembly properties, interfacial tension and interfacial viscosity, etc. The self-assembly procedure of interfacial film of vacuum residua fractions were focused by means of the Wilhelmy plate method (Paper 1). The self-assembly states of interfacial film of vacuum residua fraction from Iranian Heavy and Daqing crude oil have been revealed by using Langmuir-Blodgett technology respectively (Paper II and Paper III). From measurement of the interfacial shear viscosity, the mechanical strength of the interfacial film formed by the vacuum residua fraction has been described (Paper IV) and the roles of the surfactants added in the interfacial film have been confirmed (Paper V). At the same time, the oil/water interfacial tensions of vacuum residua fractions from the three kinds of crude oil have been studied and compared (Paper VI and Paper VII). Characteristic properties of emulsions stabilized by the vacuum residua, such as Zeta potential (Paper VIII) and particle size distribution (Paper IX), have also been studied. An attempt has been made to explain the variations of emulsion properties in terms of the interfacial self-assembly of vacuum residua fractions. Finally, based up the above research and using chemometric methods