WorldWideScience

Sample records for acetylenes

  1. Formation of carbon nanostructures using acetylene, argon-acetylene and argon-hydrogen-acetylene plasmas

    International Nuclear Information System (INIS)

    Marcinauskas, L.; Grigonis, A.; Minialga, V.; Marcinauskas, L.; Valincius, V.

    2013-01-01

    The films prepared in argon-acetylene plasma are attributed to graphite-like carbon films. Addition of the hydrogen decreases growth rate and the surface roughness of the films and lead to the formation of nanocrystalline graphite. The carbon nanotubes were formed at low (≤ 450°C; p = 40 Pa) temperature in pure acetylene plasma. (authors)

  2. Acetylene on Titan

    Science.gov (United States)

    Singh, Sandeep; McCord, Thomas B.; Combe, Jean-Philippe; Rodriguez, Sebastien; Cornet, Thomas; Le Mouélic, Stéphane; Clark, Roger Nelson; Maltagliati, Luca; Chevrier, Vincent

    2016-10-01

    Saturn's moon Titan possesses a thick atmosphere that is mainly composed of N2 (98%), CH4 (2 % overall, but 4.9% close to the surface) and less than 1% of minor species, mostly hydrocarbons [1]. A dissociation of N2 and CH4 forms complex hydrocarbons in the atmsophere and acetylene (C2H2) and ethane (C2H6) are produced most abundently. Since years, C2H2 has been speculated to exist on the surface of Titan based on its high production rate in the stratosphere predicted by photochemical models [2,3] and from its detection as trace gas sublimated/evaporated from the surface after the landing of the Huygens probe by the Gas Chromatograph Mass Spectrometer (GCMS) [1]. Here we show evidence of acetylene (C2H2) on the surface of Titan by detecting absorption bands at 1.55 µm and 4.93 µm using Cassini Visual and Infrared Mapping Spectrometer (VIMS) [4] at equatorial areas of eastern Shangri-La, and Fensal-Aztlan/Quivira.An anti-correlation of absorption band strength with albedo indicates greater concentrations of C2H2 in the dark terrains, such as sand dunes and near the Huygens landing site. The specific location of the C2H2 detections suggests that C2H2 is mobilized by surface processes, such as surface weathering by liquids through dissolution/evaporation processes.References:[1]Niemann et al., Nature 438, 779-784 (2005).[2]Lavvas et al., Planetary and Space Science 56, 67 - 99 (2008).[3]Lavvas et al., Planetary and Space Science 56, 27 - 66 (2008).[4] Brown et al., The Cassini-Huygens Mission 111-168 (Springer, 2004).

  3. Thermal Conversion of Methane to Acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

    2000-01-01

    This report describes the experimental demonstration of a process for the direct thermal conversion of methane to acetylene. The process utilizes a thermal plasma heat source to dissociation products react to form a mixture of acetylene and hydrogen. The use of a supersonic expansion of the hot gas is investigated as a method of rapidly cooling (quenching) the product stream to prevent further reaction or thermal decomposition of the acetylene which can lower the overall efficiency of the process.

  4. 46 CFR 147.70 - Acetylene.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other... standard cubic feet) of acetylene may be on board a vessel engaged in industrial operations, if it is...

  5. Plasma Thermal Conversion of Methane to Acetylene

    International Nuclear Information System (INIS)

    Fincke, James Russell; Anderson, Raymond Paul; Hyde, Timothy Allen; Detering, Brent Alan; Wright, Randy Ben; Bewley, Randy Lee; Haggard, Delon C; Swank, William David

    2002-01-01

    This paper describes a re-examination of a known process for the direct plasma thermal conversion of methane to acetylene. Conversion efficiencies (% methane converted) approached 100% and acetylene yields in the 90-95% range with 2-4% solid carbon production were demonstrated. Specificity for acetylene was higher than in prior work. Improvements in conversion efficiency, yield, and specificity were due primarily to improved injector design and reactant mixing, and minimization of temperature gradients and cold boundary layers. At the 60-kilowatt scale cooling by wall heat transfer appears to be sufficient to quench the product stream and prevent further reaction of acetylene resulting in the formation of heavier hydrocarbon products or solid carbon. Significantly increasing the quenching rate by aerodynamic expansion of the products through a converging-diverging nozzle led to a reduction in the yield of ethylene but had little effect on the yield of other hydrocarbon products. While greater product selectivity for acetylene has been demonstrated, the specific energy consumption per unit mass of acetylene produced was not improved upon. A kinetic model that includes the reaction mechanisms resulting in the formation of acetylene and heavier hydrocarbons, through benzene, is described

  6. Exchange reaction of acetylene-d2 with hydrogen chloride

    International Nuclear Information System (INIS)

    Bopp, A.F.; Kern, R.D.

    1975-01-01

    A mixture containing 3 percent each of the reactants C 2 D 2 and HCl in an Ne--Ar diluent was studied over the temperature range 1650 to 2600 0 K utilizing a shock tube coupled to a time-of-flight mass spectrometer. Plots of the mole fractions f of the exchange products, DCl and C 2 HD, revealed two distinct regions of growth: (a) an initial low conversion region characterized by an induction period t/sub i/; and (b) a region of accelerated exchange during which exchange products were formed with a quadratic dependence of the reaction time. These two regions labeled a and b were combined using two empirical equations, 1 - f/sub a//f/sub eq,a/ = exp [-k/sub a/[M]t], where t less than or equal to t/sub i/, and 1 - f/sub b//f/sub eq,b/ = exp [-k/sub b/[M](t - t/sub i/) 2 ], in order to represent the entire reaction profile at any given temperature within the interval investigated. The Arrhenius parameters for k/sub a/ and k/sub b/ were determined to be 10 11 . 15+-0 . 30 exp (-19990 +- 2850/RT) and 10 16 . 40+-0 . 41 exp (-31480 +- 4200/RT), respectively, for DCl and 10 11 . 69+-0 . 29 exp (-19150 +- 2740/RT) and 10 15 . 24+-0 . 34 exp (-17620 +- 3480/RT) for C 2 HD. The units for k/sub a/ are cm 3 mol -1 sec -1 and cm 3 mol -1 sec -2 for k/sub b/. Activation energies are reported in cal mol -1 . Comparison with the profiles obtained for acetylene pyrolysis strongly suggests that the mechanism for the exchange is atomic. Furthermore, the exchange experiments indicate that the initial step in the pyrolysis of acetylene is the disproportionation reaction, 2C 2 H 2 → C 2 H + C 2 H 3

  7. Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    KAUST Repository

    Hu, Tong-Liang

    2015-06-04

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal–organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process.

  8. Acetylene diffusion in Na-Y zeolite

    Indian Academy of Sciences (India)

    ideal guest molecule to start with. Here we ... In that case the incoherent scattering law, Sinc(Q, ω), alone describes the dynamics. Q(=k−k0) is the .... The results of QENS measurements to study the diffusion of acetylene gas in zeolite. Na-Y at ...

  9. Two new acetylenic compounds from Asparagus officinalis.

    Science.gov (United States)

    Li, Xue-Mei; Cai, Jin-Long; Wang, Wen-Xiang; Ai, Hong-Lian; Mao, Zi-Chao

    2016-01-01

    Two new acetylenic compounds, asparoffins A (1) and B (2), together with two known compounds, nyasol (3) and 3″-methoxynyasol (4), were isolated from stems of Asparagus officinalis. The structures of two new compounds were elucidated on the basis of detailed spectroscopic analyses (UV, IR, MS, 1D, and 2D NMR). All compounds were evaluated for their cytotoxicities against three human cancer cell lines.

  10. Aromatic Radicals-Acetylene Particulate Matter Chemistry

    Science.gov (United States)

    2011-12-01

    solutions include deactivated fused silica-lined tubing provided by Sigma-Aldrich. The internal wall of these tubes is covered by a thin layer of fused... Ser 809 S. Marshfield, RM 520, Chicago, IL 60612 USACE HUMPHREYS ENGR CTR SPT ACTIVITY Attn: CECT-HC 7701 Telegraph Road Alexandria, VA 22315...Model, m-Xylene Oxidation, Phenyl + Acetylene, Phenyl Pyrolysis, Gas Chromatography , Potential Energy Surface, Ab-Initio Calculations. None 133

  11. Measurements of acetylene in air extracted from polar ice cores

    Science.gov (United States)

    Nicewonger, M. R.; Aydin, M.; Montzka, S. A.; Saltzman, E. S.

    2016-12-01

    Acetylene (ethyne) is a non-methane hydrocarbon emitted during combustion of fossil fuels, biofuels, and biomass. The major atmospheric loss pathway of acetylene is oxidation by hydroxyl radical with a lifetime estimated at roughly two weeks. The mean annual acetylene levels over Greenland and Antarctica are 250 ppt and 20 ppt, respectively. Firn air measurements suggest atmospheric acetylene is preserved unaltered in polar snow and firn. Atmospheric reconstructions based on firn air measurements indicate acetylene levels rose significantly during the twentieth century, peaked near 1980, then declined to modern day levels. This historical trend is similar to that of other fossil fuel-derived non-methane hydrocarbons. In the preindustrial atmosphere, acetylene levels should primarily reflect emissions from biomass burning. In this study, we present the first measurements of acetylene in preindustrial air extracted from polar ice cores. Air from fluid and dry-drilled ice cores from Summit, Greenland and WAIS-Divide Antarctica is extracted using a wet-extraction technique. The ice core air is analyzed using gas chromatography and high-resolution mass spectrometry. Between 1400 to 1800 C.E., acetylene levels over Greenland and Antarctica varied between roughly 70-120 ppt and 10-30 ppt, respectively. The preindustrial Greenland acetylene levels are significantly lower than modern levels, reflecting the importance of northern hemisphere fossil fuel sources today. The preindustrial Antarctic acetylene levels are comparable to modern day levels, indicating similar emissions in the preindustrial atmosphere, likely from biomass burning. The implications of the preindustrial atmospheric acetylene records from both hemispheres will be discussed.

  12. Synthesis of acetylenic derivatives of hydroxynaphthoquinone

    International Nuclear Information System (INIS)

    Sanchez Kopper, Andres

    2010-01-01

    The acetylene derivatives synthesis 2-hydroxy-1 ,4-naphthoquinones was studied using different reaction conditions: coupling with copper and silver acetylides, Sonogashira reaction with and without CU (I) as cocatalyst. The reaction conditions are optimized for coupling of iodine lawson and ylide phenyl lawsone of iodine with various terminal acetylenes: phenyl acetylene, propargyl alcohol, 1-heptin and 2-methyl-3-butyne-2-ol. Also, reactants such as bromides of hidroxinaphthoquinones were used with protecting groups such as acetate, methoxy, phenyloxy, benzyloxy and tricloroetoxy. The synthesis of 2-hydroxy-3-(3-hydroxy-3-ynyl-1-methylbutane)-1,4-naphthoquinone, 2-methoxy-3-(2-phenylethynyl) -1,4-naphthoquinone and 2-(2-phenylethynyl)-3-(2,2,2-tricloroetoxy)-1,4-naphthoquinone was performed with rates of return of 22%, 57% and 67% respectively. The reaction of the yodolawsona was obtained with 3-chloro-3-methyl-1-butyne in the presence of CuI, CsI and Cs 2 Co 3 obtaining the enol ether: 3,3-dimethyl-2-methyl-2 ,3-dihydronaphto [2 ,3-b]furan-4,9-dione (dehydro-α-dunion), with a rate of return of 58%. This enol ether was used as a reactant for the formation, through a regioselective hydrogenation with PtO 2 /t-butanol of α-dunion with a yield of 50%. Furthermore, by acid hydrolysis with H 2 SO 4 has been possible to obtain a percentage yield of 75% streptocarpone. Both, α-dunion and streptocarpone, natural products extracted from Streptocarpus dunni shrub, with antiparasitic activity, and which so far had not presented an efficient synthesis. A mechanism is proposed for the reaction of formation of the enol ether where it is presumed the presence of a zwitterion-vinyl carbene as key intermediate of the reaction. All products were characterized by spectroscopy 1 H and 13 C-NMR, UV-Vis and IR. (author) [es

  13. Modelling non-redox enzymes: Anaerobic and aerobic acetylene ...

    Indian Academy of Sciences (India)

    Administrator

    Modelling non-redox enzymes: Anaerobic and aerobic acetylene hydratase. SABYASACHI SARKAR. Department of Chemistry, Indian Institute of Technology, Kanpur 208 016,. India. Acetaldehyde is the first metabolite produced during acetylene degradation by bacteria either aerobically or anaerobically. Conversion of ...

  14. A mid-infrared absorption diagnostic for acetylene detection

    KAUST Repository

    KC, Utsav

    2015-05-14

    Acetylene is an important combustion intermediate and plays a critical role in soot formation. Accurate measurements of trace concentrations of acetylene can be very useful in validating hydrocarbon oxidation and soot formation mechanisms. Strongest vibrational band of acetylene near 13.7 μm is probed here to develop a highly sensitive absorption diagnostic. Experiments are carried out behind reflected shock waves to measure absorption cross sections of acetylene near 730 cm−1 over a wide range of temperatures (1000–2200 K) and pressures (1–5 bar). The diagnostic is demonstrated by measuring acetylene formation during the shock-heated pyrolysis and oxidation of propene. © 2015 Springer-Verlag Berlin Heidelberg

  15. Diamond growth in oxygen-acetylene flame

    International Nuclear Information System (INIS)

    Haga, Mario S.; Nagai, Y. Ernesto; Suzuki, Carlos K.

    1995-01-01

    What was supposed to be a laboratory curiosity in the 80's, in recent years the low pressure process for the production of man-made diamond turned out to be a major target for research and development of many high-tech companies. The main reason for such an interest stems on the possibility of coating many materials with a diamond film possessing the same amazing properties of the bulk natural diamond. Polycrystalline diamond film has been deposited on Mo substrate by using oxygen-acetylene flame of a welding torch. The substrate temperature has been held constant about 700 d eg C by means of a water cooled mount designed properly. Precision flowmeters have been used to control the flow ratio oxygen/acetylene, a key parameter for the success in diamond growth. Diamond has been detected by X-ray diffraction, a fast foolproof technique for crystal identification. Another method of analysis often used in Raman spectroscopy, which is able to exhibit amorphous structure besides crystalline phase. (author)

  16. Pressure-induced polymerization in substituted acetylenes

    Energy Technology Data Exchange (ETDEWEB)

    Chellappa, Raja S.; Dattelbaum, Dana M.; Sheffield, Stephen; Robbins, David (LANL)

    2012-04-10

    A fundamental understanding of shock-induced chemical reactions in organics is still lacking and there are limited studies devoted to determining reaction mechanisms, evolution of bonding, and effect of functional group substitutions. The fast timescale of reactions occurring during shock compression create significant experimental challenges (diagnostics) to fully quantify the mechanisms involved. Static compression combined with temperature provides a complementary route to investigate the equilibrium phase space and metastable intermediates under extreme P-T conditions. In this study, we present our results from our ongoing high pressure in situ synchrotron x-ray diffraction experiments on substituted acetylenes: tert-butyl acetylene [TBA: (CH{sub 3}){sub 3}-C=CH] and ethynyl trimethylsilane [ETMS: (CH{sub 3}){sub 3}-SiC=CH]. We observed that the onset pressure of chemical reactions (at room temperature) in these compounds is higher under static compression (TBA: 12 GPa and ETMS: 17.6 GPa) when compared to shock input pressures (TBA: 6.1 GPa and ETMS: 6.6 GPa). At elevated temperatures, reactivity was observed to occur at pressures comparable to shock conditions. The products were polymeric in nature, recovered to ambient conditions with little degradation.

  17. Acetylene-Based Materials in Organic Photovoltaics

    Directory of Open Access Journals (Sweden)

    Fabio Silvestri

    2010-04-01

    Full Text Available Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (polyarylacetylenes that have been used in the field. A general introduction to (polyarylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (copolymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices.

  18. Interpenetrating polymer networks from acetylene terminated materials

    Science.gov (United States)

    Connell, J. W.; Hergenrother, P. M.

    1989-01-01

    As part of a program to develop high temperature/high performance structural resins for aerospace applications, the chemistry and properties of a novel class of interpenetrating polymer networks (IPNs) were investigated. These IPNs consist of a simple diacetylenic compound (aspartimide) blended with an acetylene terminated arylene ether oligomer. Various compositional blends were prepared and thermally cured to evaluate the effect of crosslink density on resin properties. The cured IPNs exhibited glass transition temperatures ranging from 197 to 254 C depending upon the composition and cure temperature. The solvent resistance, fracture toughness and coefficient of thermal expansion of the cured blends were related to the crosslink density. Isothermal aging of neat resin moldings, adhesive and composite specimens showed a postcure effect which resulted in improved elevated temperature properties. The chemistry, physical and mechanical properties of these materials will be discussed.

  19. Computational Screening of MOFs for Acetylene Separation.

    Science.gov (United States)

    Nemati Vesali Azar, Ayda; Keskin, Seda

    2018-01-01

    Efficient separation of acetylene (C 2 H 2 ) from CO 2 and CH 4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C 2 H 2 /CO 2 and C 2 H 2 /CH 4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C 2 H 2 /CO 2 and C 2 H 2 /CH 4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C 2 H 2 /CO 2 and C 2 H 2 /CH 4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C 2 H 2 /CO 2 selectivities of 49, 47, 24 and C 2 H 2 /CH 4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C 2 H 2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600-1,200 m 2 /g and porosities between 0.4 and 0.6 for selective separation of C 2 H 2 from CO 2 and CH 4 . These results will guide the future studies for the design of new MOFs with high C 2 H 2 separation potentials.

  20. Computational Screening of MOFs for Acetylene Separation

    Science.gov (United States)

    Nemati Vesali Azar, Ayda; Keskin, Seda

    2018-02-01

    Efficient separation of acetylene (C2H2) from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs) are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4-11 Å, surface areas in the range of 600-1,200 m2/g and porosities between 0.4-0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials.

  1. Computational Screening of MOFs for Acetylene Separation

    Directory of Open Access Journals (Sweden)

    Ayda Nemati Vesali Azar

    2018-02-01

    Full Text Available Efficient separation of acetylene (C2H2 from CO2 and CH4 is important to meet the requirement of high-purity acetylene in various industrial applications. Metal organic frameworks (MOFs are great candidates for adsorption-based C2H2/CO2 and C2H2/CH4 separations due to their unique properties such as wide range of pore sizes and tunable chemistries. Experimental studies on the limited number of MOFs revealed that MOFs offer remarkable C2H2/CO2 and C2H2/CH4 selectivities based on single-component adsorption data. We performed the first large-scale molecular simulation study to investigate separation performances of 174 different MOF structures for C2H2/CO2 and C2H2/CH4 mixtures. Using the results of molecular simulations, several adsorbent performance evaluation metrics, such as selectivity, working capacity, adsorbent performance score, sorbent selection parameter, and regenerability were computed for each MOF. Based on these metrics, the best adsorbent candidates were identified for both separations. Results showed that the top three most promising MOF adsorbents exhibit C2H2/CO2 selectivities of 49, 47, 24 and C2H2/CH4 selectivities of 824, 684, 638 at 1 bar, 298 K and these are the highest C2H2 selectivities reported to date in the literature. Structure-performance analysis revealed that the best MOF adsorbents have pore sizes between 4 and 11 Å, surface areas in the range of 600–1,200 m2/g and porosities between 0.4 and 0.6 for selective separation of C2H2 from CO2 and CH4. These results will guide the future studies for the design of new MOFs with high C2H2 separation potentials.

  2. Recent New Methodologies for Acetylenic Polymers with Advanced Functionalities.

    Science.gov (United States)

    Qiu, Zijie; Han, Ting; Lam, Jacky W Y; Tang, Ben Zhong

    2017-08-01

    Polymers synthesized from acetylenic monomers often possess electronically unsaturated fused rings and thus show versatile optoelectronic properties and advanced functionalities. To expand the family of acetylenic polymers, development of new catalyst systems and synthetic routes is critically important. We summarize herein recent research progress on development of new methodologies towards functional polymers using alkyne building blocks since 2014. The polymerizations are categorized by the number of monomer components, namely homopolymerizations, two-component polymerizations, and multicomponent polymerizations. The properties and applications of acetylenic polymers, such as aggregation-induced emission, fluorescent photopatterning, light refraction, chemosensing, mechanochromism, chain helicity, etc., are also discussed.

  3. Anaerobic oxidation of acetylene by estuarine sediments and enrichment cultures

    International Nuclear Information System (INIS)

    Culbertson, C.W.; Zehnder, A.J.B.; Oremland, R.S.

    1981-01-01

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloroamphenicol, air, and autoclaving. Addition of 14 C 2 H 2 to slurries resulted in the formation of 14 CO 2 and the transient appearance of 14 C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C 2 H 2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C 2 H 2

  4. Ion structure and sequence of ion formation in acetylene flames

    Energy Technology Data Exchange (ETDEWEB)

    Larionova, I.A.; Fialkov, B.S.; Kalinich, K.YA.; Fialkov, A.B.; Ospanov, B.S.

    1993-06-01

    Results of a study of the ion composition of acetylene-air flames burning at low pressures are reported. Data on ion formation are compared for flames of saturated hydrocarbons, oxygen-containing fuels, and acetylene. It is shown that the characteristics of ion formation in the flame front and directly ahead of it are similar to those observed in flames of other fuels. These characteristics, however, are different in the low-temperature region. 9 refs.

  5. Microporous metal–organic framework with dual functionalities for highly efficient removal of acetylene from ethylene/acetylene mixtures

    KAUST Repository

    Hu, Tong-Liang; Wang, Hailong; Li, Bin; Krishna, Rajamani; Wu, Hui; Zhou, Wei; Zhao, Yunfeng; Han, Yu; Wang, Xue; Zhu, Weidong; Yao, Zizhu; Xiang, Shengchang; Chen, Banglin

    2015-01-01

    amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated

  6. ACETYLENE ON TITAN’S SURFACE

    International Nuclear Information System (INIS)

    Singh, S.; McCord, T. B.; Combe, J-Ph.; Rodriguez, S.; Maltagliati, L.; Cornet, T.; Mouélic, S. Le; Clark, R. N.; Chevrier, V. F.

    2016-01-01

    Titan’s atmosphere is opaque in the near-infrared due to gaseous absorptions, mainly by methane, and scattering by aerosols, except in a few “transparency windows.” Thus, the composition of Titan’s surface remains difficult to access from space and is still poorly constrained. Photochemical models suggest that most of the organic compounds formed in the atmosphere are heavy enough to condense and build up at the surface in liquid and solid states over geological timescales. Acetylene (C 2 H 2 ) net production in the atmosphere is predicted to be larger than any other compound and C 2 H 2 has been speculated to exist on the surface of Titan. C 2 H 2 was detected as a trace gas sublimated/evaporated from the surface using the Gas Chromatograph Mass Spectrometer after the landing of the Huygens probe. Here we show evidence of C 2 H 2 on the surface of Titan by detecting absorption bands at 1.55 and 4.93 μ m using the Cassini Visual and Infrared Mapping Spectrometer at three different equatorial areas—Tui Regio, eastern Shangri La, and Fensal–Aztlan/Quivira. We found that C 2 H 2 is preferentially detected in low-albedo areas, such as sand dunes and near the Huygens landing site. The specific location of the C 2 H 2 detections suggests that C 2 H 2 is mobilized by surface processes, such as surface weathering by liquids through dissolution/evaporation processes.

  7. Studies on panax acetylenes: absolute structure of a new panax acetylene, and inhibitory effects of related acetylenes on the growth of L-1210 cells.

    Science.gov (United States)

    Satoh, Yoshio; Satoh, Mitsuru; Isobe, Kimiaki; Mohri, Kunihiko; Yoshida, Yuki; Fujimoto, Yasuo

    2007-04-01

    A new Panax acetylene, 3-oxo-PQ-1 (1), was isolated from Panax quinquefolium. The absolute configurations of 3-oxo-PQ-1 (1) and PQ-1 (2) were determined to be (9R,10R) and (3R,9R,10R), respectively, by synthesizing 1 and 2 starting from D-(-)-diethyl tartrate, and by synthesizing their stereoisomers from L-(+)-diethyl tartrate. The growth inhibitory effects of Panax acetylenes (1-8) and their stereoisomers against leukemia cells were tested. Unnatural acetylenes having the (3S)-configuration (2, 5, 6, 7, 8; IC(50)=0.01-0.1 microg/ml) were found to be approximately ten times more potent than natural acetylenes (IC(50)=0.1-1.0 microg/ml) with the (3R)-configuration. Potency differences due to the configuration at C-9 and C-10 were unrelated to this stereochemistry. The C(14)-polyacetylenes, PQ-8 (4) and its isomer (IC(50)=1.0-10.0 microg/ml), were found to exhibit weaker cytotoxicity than the C(17)-polyacetylenes.

  8. ACETYLENE ON TITAN’S SURFACE

    Energy Technology Data Exchange (ETDEWEB)

    Singh, S.; McCord, T. B.; Combe, J-Ph. [Bear Fight Institute, 22 Fiddlers Rd, Winthrop, WA 98862 (United States); Rodriguez, S.; Maltagliati, L. [Laboratoire Astrophysique, Instrumentation et Modélisation (AIM), CNRS-UMR 7158, Université Paris-Diderot, CEA-SACLAY, F-91191 Gif sur Yvette (France); Cornet, T. [European Space Agency (ESA), European Space Astronomy Centre (ESAC), P.O. BOX 78, E-28691 Villanueva de la Caada, Madrid (Spain); Mouélic, S. Le [Laboratoire de Planétologie et Géodynamique de Nantes, Université de Nantes, UMR 6112 CNRS, 2 rue de la Houssiniére BP92208, Nantes Cedex 3 (France); Clark, R. N. [U.S. Geological Survey, Denver Federal Center, Denver, CO 80225 (United States); Chevrier, V. F., E-mail: ssingh@bearfightinstitute.com [Arkansas Center for Space and Planetary Science, University of Arkansas, Fayetteville, AR 72701 (United States)

    2016-09-01

    Titan’s atmosphere is opaque in the near-infrared due to gaseous absorptions, mainly by methane, and scattering by aerosols, except in a few “transparency windows.” Thus, the composition of Titan’s surface remains difficult to access from space and is still poorly constrained. Photochemical models suggest that most of the organic compounds formed in the atmosphere are heavy enough to condense and build up at the surface in liquid and solid states over geological timescales. Acetylene (C{sub 2}H{sub 2}) net production in the atmosphere is predicted to be larger than any other compound and C{sub 2}H{sub 2} has been speculated to exist on the surface of Titan. C{sub 2}H{sub 2} was detected as a trace gas sublimated/evaporated from the surface using the Gas Chromatograph Mass Spectrometer after the landing of the Huygens probe. Here we show evidence of C{sub 2}H{sub 2} on the surface of Titan by detecting absorption bands at 1.55 and 4.93 μ m using the Cassini Visual and Infrared Mapping Spectrometer at three different equatorial areas—Tui Regio, eastern Shangri La, and Fensal–Aztlan/Quivira. We found that C{sub 2}H{sub 2} is preferentially detected in low-albedo areas, such as sand dunes and near the Huygens landing site. The specific location of the C{sub 2}H{sub 2} detections suggests that C{sub 2}H{sub 2} is mobilized by surface processes, such as surface weathering by liquids through dissolution/evaporation processes.

  9. Reactions of acetylenes with hypophosphorous and phosphonous acids

    International Nuclear Information System (INIS)

    Nifant'ev, E.E.; Solovetskaya, L.A.; Maslennikova, V.I.; Magdeeva, R.K.; Sergeev, N.M.

    1986-01-01

    Alkenylphosphonous, alkenylphosphinic, and alkylenebisphosphinic acids were prepared for the first time. The course of the hydrophosphorylation of 1-alkynes depends on the form of the reagent used. The homolytic hydrophosphorylation of acetylenes with hypophosphorous acid proceeds mainly with the participation of one molecule of the acid. The addition of phosphonous acids to acetylenic hydrocarbons leads to both mono- and di-phosphorylated adducts. The nature of the phosphonous acid taken has a substantial influence on the readiness with which the alkylenebisphosphinic acids are formed. Study of the stereoselectivity of the reactions showed that in the case of the monoaddition of hypophosphorous and phosphonous acids to acetylenes mixtures of cis and trans isomeric products are always formed. Phosphorous 31 and carbon 13 NMR spectra are analyzed

  10. Ethane and acetylene abundances in the Jovian atmosphere

    Science.gov (United States)

    Tokunaga, A.; Knacke, R. F.; Owen, T.

    1976-01-01

    The paper reports spectra of Jupiter in the spectral region from 755 to 850 kaysers, which covers the nu-9 fundamental of ethane and contains lines from the R branch of the nu-5 fundamental of acetylene. The monochromatic absorption coefficient of the central Q branch of the nu-9 fundamental of ethane, which was determined in the laboratory, is applied in a radiative-transfer calculation to evaluate the ethane mixing ratio in the Jovian atmosphere; the present data are also used to place an upper limit on the acetylene mixing ratio. For the radiative-transfer calculation, emission intensity is computed for the region above the 0.02-atm level assuming both an isothermal inversion layer and a previously reported temperature profile. The resulting maximum mixing ratios consistent with the observations are 0.00003 for ethane and 7.5 by 10 to the -8th power for acetylene.

  11. Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein

    OpenAIRE

    Rosner, Bettina M.; Schink, Bernhard

    1995-01-01

    Acetylene hydratase of the mesophilic fermenting bacterium Pelobacter acetylenicus catalyzes the hydration of acetylene to acetaldehyde. Growth of P. acetylenicus with acetylene and specific acetylene hydratase activity depended on tungstate or, to a lower degree, molybdate supply in the medium. The specific enzyme activity in cell extract was highest after growth in the presence of tungstate. Enzyme activity was stable even after prolonged storage of the cell extract or of the purified prote...

  12. Efficient separation of ethylene from acetylene/ethylene mixtures by a flexible-robust metalorganic framework

    NARCIS (Netherlands)

    Li, L.; Lin, R.-B.; Krishna, R.; Wang, X.; Li, B.; Wu, H.; Li, J.; Zhou, W.; Chen, B.

    2017-01-01

    During the production of polymer-grade ethylene, trace amounts of acetylene (about 1%) in the ethylene feed need to be reduced to 40 parts per million (ppm). We herein report a metal–organic framework (MOF) of flexible-robust nature for the efficient removal of acetylene from acetylene/ethylene

  13. Fuzzy logic control for selective hydrogenation of acetylene in ethylene rich streams using visual basic

    International Nuclear Information System (INIS)

    Malik, S.R.; Suleman, H.; Khan, J.R.

    2010-01-01

    Presence of acetylene is technically disadvantageous in the ethylene rich gas streams from steam crackers. Acetylene tends to polymerize and inactivates the transition metal catalysts, forming highly explosive compounds. The acetylene content has to be selectively reduced to less than one part per million for such streams. The acetylene hydrogenation unit requires stringent control parameters and needs specialized process control techniques for its operation. This study is concerned with application of Fuzzy Logic Control to manipulate and control the process plant with higher precision and greater simplicity. The control program has been written in visual Basic and entails all major scenarios of work modes for successful hydrogenation of Acetylene. (author)

  14. Potent In Vitro Antifungal Activities of Naturally Occurring Acetylenic Acids▿

    Science.gov (United States)

    Li, Xing-Cong; Jacob, Melissa R.; Khan, Shabana I.; Ashfaq, M. Khalid; Babu, K. Suresh; Agarwal, Ameeta K.; ElSohly, Hala N.; Manly, Susan P.; Clark, Alice M.

    2008-01-01

    Our continuing effort in antifungal natural product discovery has led to the identification of five 6-acetylenic acids with chain lengths from C16 to C20: 6-hexadecynoic acid (compound 1), 6-heptadecynoic acid (compound 2), 6-octadecynoic acid (compound 3), 6-nonadecynoic acid (compound 4), and 6-icosynoic acid (compound 5) from the plant Sommera sabiceoides. Compounds 2 and 5 represent newly isolated fatty acids. The five acetylenic acids were evaluated for their in vitro antifungal activities against Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Candida parapsilosis, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Trichophyton mentagrophytes, and Trichophyton rubrum by comparison with the positive control drugs amphotericin B, fluconazole, ketoconazole, caspofungin, terbinafine, and undecylenic acid. The compounds showed various degrees of antifungal activity against the 21 tested strains. Compound 4 was the most active, in particular against the dermatophytes T. mentagrophytes and T. rubrum and the opportunistic pathogens C. albicans and A. fumigatus, with MICs comparable to several control drugs. Inclusion of two commercially available acetylenic acids, 9-octadecynoic acid (compound 6) and 5,8,11,14-eicosatetraynoic acid (compound 7), in the in vitro antifungal testing further demonstrated that the antifungal activities of the acetylenic acids were associated with their chain lengths and positional triple bonds. In vitro toxicity testing against mammalian cell lines indicated that compounds 1 to 5 were not toxic at concentrations up to 32 μM. Furthermore, compounds 3 and 4 did not produce obvious toxic effects in mice at a dose of 34 μmol/kg of body weight when administered intraperitoneally. Taking into account the low in vitro and in vivo toxicities and significant antifungal potencies, these 6-acetylenic acids may be excellent leads for further preclinical studies. PMID:18458131

  15. Potent in vitro antifungal activities of naturally occurring acetylenic acids.

    Science.gov (United States)

    Li, Xing-Cong; Jacob, Melissa R; Khan, Shabana I; Ashfaq, M Khalid; Babu, K Suresh; Agarwal, Ameeta K; Elsohly, Hala N; Manly, Susan P; Clark, Alice M

    2008-07-01

    Our continuing effort in antifungal natural product discovery has led to the identification of five 6-acetylenic acids with chain lengths from C(16) to C(20): 6-hexadecynoic acid (compound 1), 6-heptadecynoic acid (compound 2), 6-octadecynoic acid (compound 3), 6-nonadecynoic acid (compound 4), and 6-icosynoic acid (compound 5) from the plant Sommera sabiceoides. Compounds 2 and 5 represent newly isolated fatty acids. The five acetylenic acids were evaluated for their in vitro antifungal activities against Candida albicans, Candida glabrata, Candida krusei, Candida tropicalis, Candida parapsilosis, Cryptococcus neoformans, Aspergillus fumigatus, Aspergillus flavus, Aspergillus niger, Trichophyton mentagrophytes, and Trichophyton rubrum by comparison with the positive control drugs amphotericin B, fluconazole, ketoconazole, caspofungin, terbinafine, and undecylenic acid. The compounds showed various degrees of antifungal activity against the 21 tested strains. Compound 4 was the most active, in particular against the dermatophytes T. mentagrophytes and T. rubrum and the opportunistic pathogens C. albicans and A. fumigatus, with MICs comparable to several control drugs. Inclusion of two commercially available acetylenic acids, 9-octadecynoic acid (compound 6) and 5,8,11,14-eicosatetraynoic acid (compound 7), in the in vitro antifungal testing further demonstrated that the antifungal activities of the acetylenic acids were associated with their chain lengths and positional triple bonds. In vitro toxicity testing against mammalian cell lines indicated that compounds 1 to 5 were not toxic at concentrations up to 32 muM. Furthermore, compounds 3 and 4 did not produce obvious toxic effects in mice at a dose of 34 mumol/kg of body weight when administered intraperitoneally. Taking into account the low in vitro and in vivo toxicities and significant antifungal potencies, these 6-acetylenic acids may be excellent leads for further preclinical studies.

  16. Acetylene Resembling Effect of Ethylene on Seed Germination: Evaluating the Effect of Acetylene Released from Calcium Carbide

    Directory of Open Access Journals (Sweden)

    Kambiz MASHAYEKHI

    2015-09-01

    Full Text Available Some vegetable seeds need a very long time to germinate. In these kinds of seeds the second phase of germination is very long. As acetylene’s chemical structure is almost similar to the gaseous hormone ethylene, its’ physiological effect on seed germination should be very similar as well. Therefore, an experiment was established in order to enhance seed germination, by treating seeds with acetylene released from interaction of calcium carbide (CaC2 with water (H2O. A simple system was designed for efficient and proper use of gaseous acetylene resulted from the two substrates interaction, which conducted the produced gas obtained inside the interaction chamber into a sealed container wherein seeds were floating in water. This experiment aimed to evaluate the effect of one concentration of acetylene with different exposure periods (between 1 to 8 hours on parsley, celery and Swees chard seeds’ germination (chosen as late germinating vegetables. The effect of acetylene on seed germination speed and percent was investigated. There were significant differences in both percent and speed of germination within the various treatments. By floating for 3, 5 and 3 hours for parsley, celery and Swiss chard respectively, the highest germination rates were observed. The highest germination speed was achieved by 5, 5 and 3 hours floating respectively for parsley, celery and Swiss chard. Based on the results obtained, the current experiment suggests that acetylene has positive effect on enhancing seed germination of named vegetables, and played the role of ethylene, its effects resembling in regard to seed germination process.

  17. Detonation engine fed by acetylene-oxygen mixture

    Science.gov (United States)

    Smirnov, N. N.; Betelin, V. B.; Nikitin, V. F.; Phylippov, Yu. G.; Koo, Jaye

    2014-11-01

    The advantages of a constant volume combustion cycle as compared to constant pressure combustion in terms of thermodynamic efficiency has focused the search for advanced propulsion on detonation engines. Detonation of acetylene mixed with oxygen in various proportions is studied using mathematical modeling. Simplified kinetics of acetylene burning includes 11 reactions with 9 components. Deflagration to detonation transition (DDT) is obtained in a cylindrical tube with a section of obstacles modeling a Shchelkin spiral; the DDT takes place in this section for a wide range of initial mixture compositions. A modified ka-omega turbulence model is used to simulate flame acceleration in the Shchelkin spiral section of the system. The results of numerical simulations were compared with experiments, which had been performed in the same size detonation chamber and turbulent spiral ring section, and with theoretical data on the Chapman-Jouguet detonation parameters.

  18. Cryosolution infrared study of hydrogen bonded halothane acetylene complex

    Science.gov (United States)

    Melikova, S. M.; Rutkowski, K. S.; Rospenk, M.

    2018-05-01

    The interactions between halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) and acetylene (C2H2) are studied by FTIR spectroscopy. Results obtained in liquid cryosolutions in Kr suggest weak complex formation stabilized by H - bond. The complexation enthalpy (∼11 kJ/mol) is evaluated in a series of temperature measurements (T ∼ 120-160 K) of integrated intensity of selected bands performed in liquefied Kr. The quantum chemical MP2/6-311++G(2d,2p) calculations predict four different structures of the complex. The most stable and populated (94% at T∼120 K) structure corresponds to the H - bond between H atom of halothane and pi-electron of triple bond between C atoms of acetylene. Wave numbers of vibrational bands of the most stable structure are calculated in anharmonic approximation implemented in Gaussian program.

  19. Spectrum of acetylene fluorescence excited by single XUV photons

    International Nuclear Information System (INIS)

    Schmieder, R.W.

    1982-01-01

    The spectrum of visible emission from photofragments of acetylene excited by single 16.85 eV photons has been recorded for the first time. The spectrum is dominated by the Swan and Deslandres-d'Azambuja bands of C 2 and the 431.5 nm band of CH. The yields of these emissions are of the order 10 -3 photons per absorbed incident photon. The experimental conditions suggest that the emission results from primary C* 2 and CH* photofragments

  20. The X-ray emission spectrum of gaseous acetylene

    International Nuclear Information System (INIS)

    Brammer, R.; Rubensson, J.E.; Wassdahl, N.; Nordgren, J.

    1987-01-01

    The X-ray emission spectrum of acetylene in the gas phase has been recorded using a 10 m grazing incidence spectrometer. Analysis of the spectrum is made based on calculations of total energies, potential curves and Franck-Condon vibrational intensities. Four emission bands are seen with the 1 π u band exhibiting vibrational structure. Analysis of the vibrations gives the CIs ionization energy. High energy satellite structure is observed and interpreted. (orig.)

  1. Ring current models for acetylene and ethylene molecules

    International Nuclear Information System (INIS)

    Pelloni, Stefano; Lazzeretti, Paolo

    2009-01-01

    Spatial models of the current density vector field, induced in the electronic cloud of the acetylene and ethylene molecules by a uniform, time-independent magnetic field, are discussed in terms of topological stagnation graphs and three-dimensional streamline plots. The models are validated by documenting their ability to explain magnetic susceptibility and nuclear magnetic shieldings of carbon and hydrogen via related shielding density maps

  2. How different is the borazine-acetylene dimer from the benzene-acetylene dimer? A matrix isolation infrared and ab initio quantum chemical study

    Science.gov (United States)

    Verma, Kanupriya; Viswanathan, K. S.; Majumder, Moumita; Sathyamurthy, N.

    2017-11-01

    The 1:1 dimer of borazine-acetylene has been studied for the first time, both experimentally and computationally. The borazine-acetylene dimer was trapped in Ar and N2 matrices, and studied using infrared spectroscopy. Our experiments clearly revealed two isomers of the borazine-acetylene complex, one in which the N-H of borazine interacted with the carbon of acetylene, and another in which the C-H of acetylene formed a hydrogen bond with a nitrogen atom of borazine. The formation of both isomers in the matrix was evidenced by shifts in the vibrational frequencies of the appropriate modes. Reassuringly, the experimental observations were corroborated by our computations using the second-order Møller-Plesset perturbation theoretic method and coupled-cluster singles, doubles and perturbative triples method in conjunction with different Dunning basis sets, which indicated both these isomers to be stable minima, with the N-HṡṡṡC complex being the global minimum. Atoms-in-molecules and energy decomposition analysis were also carried out for the different isomers of the dimer. These studies reveal that replacing the three C-C linkages in benzene with three B-N linkages in borazine modifies the interaction in the dimer sufficiently, to result in a different potential energy landscape for the borazine-acetylene system when compared with the benzene-acetylene system.

  3. BASF and acetylene. 70 years of reppe chemistry - long-standing reliability and promising future - and now, the only natural gas based clean technology for acetylene production

    Energy Technology Data Exchange (ETDEWEB)

    Vicari, M. [BASF SE, Ludwigshafen (Germany)

    2013-11-01

    Acetylene is still an attractive intermediate synthesis component because carbon in methane from natural gas comes at a lower price than carbon in naphtha from crude oil or coal. Acetylene can be understood as a product of C-C coupling and functionalization. Beginning in the 1950s, BASF developed the partial oxidation (Pox) process, in addition to the electric arc process dating from the 1930s and the submerged flame process. The originally developed Pox process came along with severe emissions of hydrocarbons to the environment. Nowadays it is extremely important to have a clean, environmentally friendly technology. So in the 1990s a closed water-quench process was developed and built in the United States. The presentation focuses on the ways of making acetylene, the use of acetylene and BASF's closed water-quench process based on natural gas. This process will be presented including some important safety aspects. The process is available for licensing. (orig.)

  4. Design and experimental investigations on six-stroke SI engine using acetylene with water injection.

    Science.gov (United States)

    Gupta, Keshav; Suthar, Kishanlal; Jain, Sheetal Kumar; Agarwal, Ghanshyam Das; Nayyar, Ashish

    2018-06-02

    In the present study, a four-stroke cycle gasoline engine is redesigned and converted into a six-stroke cycle engine and experimental study has been conducted using gasoline and acetylene as fuel with water injection at the end of the recompression stroke. Acetylene has been used as an alternative fuel along with gasoline and performance of the six-stroke spark ignition (SI) engine with these two fuels has been studied separately and compared. Brake power and thermal efficiency are found to be 5.18 and 1.55% higher with acetylene as compared to gasoline in the six-stroke engine. However, thermal efficiency is found to be 45% higher with acetylene in the six-stroke engine as compared to four-stroke SI engine. The CO and HC emissions were found to be reduced by 13.33 and 0.67% respectively with acetylene as compared to gasoline due to better combustion of acetylene. The NO x emission was reduced by 5.65% with acetylene due to lower peak temperature by water injection. The experimental results showed better engine performance and emissions with acetylene as fuel in the six-stroke engine.

  5. Heterocycles by Transition Metals Catalyzed Intramolecular Cyclization of Acetylene Compounds

    International Nuclear Information System (INIS)

    Vizer, S.A.; Yerzhanov, K.B.; Dedeshko, E.C.

    2003-01-01

    Review shows the new strategies in the synthesis of heterocycles, having nitrogen, oxygen and sulfur atoms, via transition metals catalyzed intramolecular cyclization of acetylenic compounds on the data published at the last 30 years, Unsaturated heterocyclic compounds (pyrroles and pyrroline, furans, dihydro furans and benzofurans, indoles and iso-indoles, isoquinolines and isoquinolinones, aurones, iso coumarins and oxazolinone, lactams and lactones with various substitutes in heterocycles) are formed by transition metals, those salts [PdCl 2 , Pd(OAc) 2 , HgCl 2 , Hg(OAc) 2 , Hg(OCOCF 3 ) 2 , AuCl 3 ·2H 2 O, NaAuCl 4 ·2H 2 O, CuI, CuCl], oxides (HgO) and complexes [Pd(OAc) 2 (PPh 3 )2, Pd(PPh 3 ) 4 , PdCl 2 (MeCN) 2 , Pd(OAc ) 2 /TPPTS] catalyzed intramolecular cyclization of acetylenic amines, amides, ethers, alcohols, acids, ketones and βdiketones. More complex hetero polycyclic systems typical for natural alkaloids can to obtain similar. Proposed mechanisms of pyrroles, isoquinolines, iso indoles and indoles, benzofurans and iso coumarins, thiazolopyrimidinones formation are considered. (author)

  6. Analysis of the polymeric film and fine dust obtained in plasma of acetylene and acetylene-nitrogen

    International Nuclear Information System (INIS)

    Rojas, Andres F; Ortiz, Jairo A; Devia Alfonso

    1998-01-01

    The results are presented from the resistance analyses to the corrosion of the polymeric covering obtained in plasma of acetylene, on a substrata of aluminum alloy, with the techniques of metallographic analysis, infrared and electrochemical, as much for the fine dust as for the grown film on aluminum. Also, the results of the electrochemical test of polarization made to these films will be shown, which demonstrated an improvement of 2.6 and 4.6 times in the resistance to the corrosion when the material treaty is exposed NaCl 0.2 N and Na H2 PO4 01 M, respectively, in comparison with the substrata without recovering. For the movie obtained in acetylene /nitrogen plasma on steel 1016 the micrographs of the superficial structure of the material they will be shown before and after being treated, which were used to measure the thickness of the cover; also, it will be given to know the results of the tests of adhesion and qualitative analysis of resistance before diverse chemical agents (such as: Benzene, Toluene, H2SO4, HNO3, NaCl, CACO3 NaOH and KOH) and the resistance results are presented from the cover to them

  7. A first principles study of the acetylene-water interaction

    Energy Technology Data Exchange (ETDEWEB)

    Tzeli, Demeter [Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrain University of Athens, P.O. Box 64 004, 157 10 Zografou, Athens, (Greece); Mavridis, Aristides [Laboratory of Physical Chemistry, Department of Chemistry, National and Kapodistrain University of Athens, P.O. Box 64 004, 157 10 Zografou, Athens, (Greece); Xantheas, Sotiris S. [Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, 906 Battelle Boulevard, P.O. Box 999, MS K8-91, Richland, Washington 99352 (United States)

    2000-04-08

    We present an extensive study of the stationary points on the acetylene-water (AW) ground-state potential energy surface (PES) aimed in establishing accurate energetics for the two different bonding scenarios that are considered. Those include arrangements in which water acts either as a proton acceptor from one of the acetylene hydrogen atoms or a proton donor to the triple bond. We used a hierarchy of theoretical methods to account for electron correlation [MP2 (second-order Moller-Plesset), MP4 (fourth-order Moller-Plesset), and CCSD(T) (coupled-cluster single double triple)] coupled with a series of increasing size augmented correlation consistent basis sets (aug-cc-pVnZ, n=2,3,4). We furthermore examined the effect of corrections due to basis set superposition error (BSSE). We found that those have a large effect in altering the qualitative features of the PES of the complex. They are responsible for producing a structure of higher (C{sub 2v}) symmetry for the global minimum. Zero-point energy (ZPE) corrections were found to increase the stability of the C{sub 2v} arrangement. For the global (water acceptor) minimum of C{sub 2v} symmetry our best estimates are {delta}E{sub e}=-2.87 kcal/mol ({delta}E{sub 0}=-2.04 kcal/mol) and a van der Waals distance of R{sub e}=2.190 Aa. The water donor arrangement lies 0.3 kcal/mol (0.5 kcal/mol including ZPE corrections) above the global minimum. The barrier for its isomerization to the global minimum is E{sub e}=0.18 kcal/mol; however, inclusion of BSSE- and ZPE-corrections destabilize the water donor arrangement suggesting that it can readily convert to the global minimum. We therefore conclude that there exists only one minimum on the PES in accordance with previous experimental observations. To this end, vibrational averaging and to a lesser extend proper description of intermolecular interactions (BSSE) were found to have a large effect in altering the qualitative features of the ground-state PES of the acetylene

  8. A first principles study of the acetylene-water interaction

    International Nuclear Information System (INIS)

    Tzeli, Demeter; Mavridis, Aristides; Xantheas, Sotiris S.

    2000-01-01

    We present an extensive study of the stationary points on the acetylene-water (AW) ground-state potential energy surface (PES) aimed in establishing accurate energetics for the two different bonding scenarios that are considered. Those include arrangements in which water acts either as a proton acceptor from one of the acetylene hydrogen atoms or a proton donor to the triple bond. We used a hierarchy of theoretical methods to account for electron correlation [MP2 (second-order Moller-Plesset), MP4 (fourth-order Moller-Plesset), and CCSD(T) (coupled-cluster single double triple)] coupled with a series of increasing size augmented correlation consistent basis sets (aug-cc-pVnZ, n=2,3,4). We furthermore examined the effect of corrections due to basis set superposition error (BSSE). We found that those have a large effect in altering the qualitative features of the PES of the complex. They are responsible for producing a structure of higher (C 2v ) symmetry for the global minimum. Zero-point energy (ZPE) corrections were found to increase the stability of the C 2v arrangement. For the global (water acceptor) minimum of C 2v symmetry our best estimates are ΔE e =-2.87 kcal/mol (ΔE 0 =-2.04 kcal/mol) and a van der Waals distance of R e =2.190 Aa. The water donor arrangement lies 0.3 kcal/mol (0.5 kcal/mol including ZPE corrections) above the global minimum. The barrier for its isomerization to the global minimum is E e =0.18 kcal/mol; however, inclusion of BSSE- and ZPE-corrections destabilize the water donor arrangement suggesting that it can readily convert to the global minimum. We therefore conclude that there exists only one minimum on the PES in accordance with previous experimental observations. To this end, vibrational averaging and to a lesser extend proper description of intermolecular interactions (BSSE) were found to have a large effect in altering the qualitative features of the ground-state PES of the acetylene-water complex. (c) 2000 American Institute

  9. Acetylene as fast food: Implications for development of life on anoxic primordial earth and in the outer solar system

    Science.gov (United States)

    Oremland, R.S.; Voytek, M.A.

    2008-01-01

    Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial processes, including methanogenesis, anaerobic methane oxidation, nitrogen fixation, and hydrogen oxidation. Fermentation of acetylene was discovered 25 years ago, and Pelobacter acetylenicus was shown to grow on acetylene by virtue of acetylene hydratase, which results in the formation of acetaldehyde. Acetaldehyde subsequently dismutates to ethanol and acetate (plus some hydrogen). However, acetylene hydratase is specific for acetylene and does not react with any analogous compounds. We hypothesize that microbes with acetylene hydratase played a key role in the evolution of Earth's early biosphere by exploiting an available source of carbon from the atmosphere and in so doing formed protective niches that allowed for other microbial processes to flourish. Furthermore, the presence of acetylene in the atmosphere of a planet or planetoid could possibly represent evidence for an extraterrestrial anaerobic ecosystem. ?? Mary Ann Liebert, Inc.

  10. Acetylene as fast food: implications for development of life on anoxic primordial Earth and in the outer solar system.

    Science.gov (United States)

    Oremland, Ronald S; Voytek, Mary A

    2008-02-01

    Acetylene occurs, by photolysis of methane, in the atmospheres of jovian planets and Titan. In contrast, acetylene is only a trace component of Earth's current atmosphere. Nonetheless, a methane-rich atmosphere has been hypothesized for early Earth; this atmosphere would also have been rich in acetylene. This poses a paradox, because acetylene is a potent inhibitor of many key anaerobic microbial processes, including methanogenesis, anaerobic methane oxidation, nitrogen fixation, and hydrogen oxidation. Fermentation of acetylene was discovered approximately 25 years ago, and Pelobacter acetylenicus was shown to grow on acetylene by virtue of acetylene hydratase, which results in the formation of acetaldehyde. Acetaldehyde subsequently dismutates to ethanol and acetate (plus some hydrogen). However, acetylene hydratase is specific for acetylene and does not react with any analogous compounds. We hypothesize that microbes with acetylene hydratase played a key role in the evolution of Earth's early biosphere by exploiting an available source of carbon from the atmosphere and in so doing formed protective niches that allowed for other microbial processes to flourish. Furthermore, the presence of acetylene in the atmosphere of a planet or planetoid could possibly represent evidence for an extraterrestrial anaerobic ecosystem.

  11. Detailed modeling of hydrocarbon nanoparticle nucleation in acetylene discharges

    International Nuclear Information System (INIS)

    Bleecker, Kathleen de; Bogaerts, Annemie; Goedheer, Wim

    2006-01-01

    The initial stage of nanoparticle formation and growth in radiofrequency acetylene (C 2 H 2 ) plasmas is investigated by means of a self-consistent one-dimensional fluid model. A detailed chemical kinetic scheme, containing electron impact, ion-neutral, and neutral-neutral reactions, has been developed in order to predict the underlying dust growth mechanisms and the most important dust precursors. The model considers 41 different species (neutrals, radicals, ions, and electrons) describing hydrocarbons (C n H m ) containing up to 12 carbon atoms. Possible routes for particle growth are discussed. Both positive and negative ion reaction pathways are considered, as consecutive anion- and cation-molecule reactions seem to lead to a fast build up of the carbon skeleton

  12. Organogermanium Chemistry: Germacyclobutanes and digermane Additions to Acetylenes

    Energy Technology Data Exchange (ETDEWEB)

    Chubb, Andrew Michael [Iowa State Univ., Ames, IA (United States)

    2003-01-01

    This dissertation comprises two main research projects. The first project, presented in Chapter 1, involves the synthesis and thermochemistry of germacyclobutanes (germetanes). Four new germetanes (spirodigermetane, diallylgermetane, dichlorogermetane, and germacyclobutane) have been synthesized using a modified di-Grignard synthesis. Diallylgermetane is shown to be a useful starting material for obtaining other germetanes, particularly the parent germetane, germacyclobutane. The gas-phase thermochemistries of spirodigermetane, diallylgermetane and germacyclobutane have been explored via pulsed stirred-flow reactor (SFR) studies, showing remarkable differences in decomposition, depending on the substitution at the germanium atom. The second project investigates the thermochemical, photochemical, and catalytic additions of several digermanes to acetylenes. The first examples of thermo- and photochemical additions of Ge-Ge bonds to C{triple_bond}C are demonstrated. Mechanistic investigations are described and comparisons are made to analogous disilane addition reactions, previously studied in their group.

  13. Assessing the long-term variability of acetylene and ethane in the stratosphere of Jupiter

    Science.gov (United States)

    Melin, Henrik; Fletcher, L. N.; Donnelly, P. T.; Greathouse, T. K.; Lacy, J. H.; Orton, G. S.; Giles, R. S.; Sinclair, J. A.; Irwin, P. G. J.

    2018-05-01

    Acetylene (C2H2) and ethane (C2H6) are both produced in the stratosphere of Jupiter via photolysis of methane (CH4). Despite this common source, the latitudinal distribution of the two species is radically different, with acetylene decreasing in abundance towards the pole, and ethane increasing towards the pole. We present six years of NASA IRTF TEXES mid-infrared observations of the zonally-averaged emission of methane, acetylene and ethane. We confirm that the latitudinal distributions of ethane and acetylene are decoupled, and that this is a persistent feature over multiple years. The acetylene distribution falls off towards the pole, peaking at ∼ 30°N with a volume mixing ratio (VMR) of ∼ 0.8 parts per million (ppm) at 1 mbar and still falling off at ± 70° with a VMR of ∼ 0.3 ppm. The acetylene distributions are asymmetric on average, but as we move from 2013 to 2017, the zonally-averaged abundance becomes more symmetric about the equator. We suggest that both the short term changes in acetylene and its latitudinal asymmetry is driven by changes to the vertical stratospheric mixing, potentially related to propagating wave phenomena. Unlike acetylene, ethane has a symmetric distribution about the equator that increases toward the pole, with a peak mole fraction of ∼ 18 ppm at about ± 50° latitude, with a minimum at the equator of ∼ 10 ppm at 1 mbar. The ethane distribution does not appear to respond to mid-latitude stratospheric mixing in the same way as acetylene, potentially as a result of the vertical gradient of ethane being much shallower than that of acetylene. The equator-to-pole distributions of acetylene and ethane are consistent with acetylene having a shorter lifetime than ethane that is not sensitive to longer advective timescales, but is augmented by short-term dynamics, such as vertical mixing. Conversely, the long lifetime of ethane allows it to be transported to higher latitudes faster than it can be chemically depleted.

  14. Pore chemistry and size control in hybrid porous materials for acetylene capture from ethylene

    KAUST Repository

    Cui, X.

    2016-05-20

    The trade-off between physical adsorption capacity and selectivity of porous materials is a major barrier for efficient gas separation and purification through physisorption. We report control over pore chemistry and size in metal coordination networks with hexafluorosilicate and organic linkers for the purpose of preferential binding and orderly assembly of acetylene molecules through cooperative host-guest and/or guest-guest interactions. The specific binding sites for acetylene are validated by modeling and neutron powder diffraction studies. The energies associated with these binding interactions afford high adsorption capacity (2.1 millimoles per gram at 0.025 bar) and selectivity (39.7 to 44.8) for acetylene at ambient conditions. Their efficiency for the separation of acetylene/ethylene mixtures is demonstrated by experimental breakthrough curves (0.73 millimoles per gram from a 1/99 mixture).

  15. A Convenient Synthesis of Conjugated Acetylenic Ketones by Copper(l)-Catalyzed under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    WANG JinXian; WEI BangGuo; ZHAO LianBiao; HU YuLai; KANG LiQing

    2001-01-01

    @@ Alkynyl ketones are useful precursors and intermediates in synthetic organic chemistry1 and has evoked considerable interest. A number of methods for the synthesis of conjugated acetylenic ketones involve the reaction a metal acetylide with an acyl chlorides or another carboxylic acid derivative have been developed 2. Recently, the synthesis of α, β-conjugated acetylenic ketones catalyzed by Pd(Ⅱ) or by copper(Ⅰ)pd(Ⅱ) reaction of 1-alkynes and acyl chlorides have been described. The acylation of terminal alkynes by acyl chlorides in the presence of catalytic amounts copper(Ⅰ) salts leading to α, β-conjugated acetylenic ketones has also been reported. However, many of these reactions suffer from lack of high pressure (17 atm), long reaction time (30 h)and require low temperatures (-78℃). Our work involves the synthesis of conjugated acetylenic ketones via the reaction of terminal alkynes with aroyl chlorides in the presence of cuprous iodide under microwave irradiation conditions.

  16. Evaluation of Sorbents for Acetylene Separation in Atmosphere Revitalization Loop Closure

    Science.gov (United States)

    Abney, Morgan B.; Miller, Lee A.; Barton, Katherine

    2012-01-01

    State-of-the-art carbon dioxide reduction technology uses a Sabatier reactor to recover water from metabolic carbon dioxide. In order to maximize oxygen loop closure, a byproduct of the system, methane, must be reduced to recover hydrogen. NASA is currently exploring a microwave plasma methane pyrolysis system for this purpose. The resulting product stream of this technology includes unreacted methane, product hydrogen, and acetylene. The hydrogen and the small amount of unreacted methane resulting from the pyrolysis process can be returned to the Sabatier reactor thereby substantially improving the overall efficiency of the system. However, the acetylene is a waste product that must be removed from the pyrolysis product. Two materials have been identified as potential sorbents for acetylene removal: zeolite 4A, a commonly available commercial sorbent, and HKUST-1, a newly developed microporous metal. This paper provides an explanation of the rationale behind acetylene removal and the results of separation testing with both materials

  17. Investigation of supercapacitors with carbon electrodes obtained from argon-acetylene arc plasma

    OpenAIRE

    Kavaliauskas, Žydrūnas

    2010-01-01

    The dissertation examines topics related to the formation of supercapacitors using plasma technology and their analysis. Plasma spray technology was used to form supercapacitors electrodes. Carbon was deposited on stainless steel surface using the atmospheric pressure argon-acetylene plasma. The deposition of nickel oxide on the surface of carbon electrodes was made using magnetron sputtering method. The influence of acetylene amount to the supercapacitors electrodes and the electrical charac...

  18. Synthesis of chirals regioisomers from D-mannitol: obtainment of a acetylenic alcohols mixture

    International Nuclear Information System (INIS)

    Cito, Antonia Maria das Gracas Lopes; Araujo, Bruno Quirino; Lopes, Jose Arimateia Dantas; Magalhes, Aderbal Farias; Magalhes, Eva Goncalves

    2009-01-01

    The synthesis of chiral acetylenic regioisomers was described by using an appropriate intermediate such as isopropylidene glycerol, a synthon widely used in the enantioselective syntheses. This intermediate was prepared from D-mannitol. The nine obtained compounds have been characterized by their respective spectral data. The mixture of chiral acetylenic alcohols showed activity against Escherichia coli when tested through the monitoring of CO 2 released during microbial respiration by using a conductimetric system. (author)

  19. Leukotriene B4 omega-hydroxylase in human polymorphonuclear leukocytes. Suicidal inactivation by acetylenic fatty acids.

    Science.gov (United States)

    Shak, S; Reich, N O; Goldstein, I M; Ortiz de Montellano, P R

    1985-10-25

    Human polymorphonuclear leukocytes (PMN) not only generate and respond to leukotriene B4 (LTB4), but also catabolize this mediator of inflammation rapidly and specifically by omega-oxidation (probably due to the action of a cytochrome P-450 enzyme). To develop pharmacologically useful inhibitors of the LTB4 omega-hydroxylase in human PMN, we devised a general scheme for synthesizing terminal acetylenic fatty acids based on the "acetylenic zipper" reaction. We found that the LTB4 omega-hydroxylase in intact PMN and in PMN sonicates is inactivated in a concentration-dependent fashion by terminal acetylenic analogues of lauric, palmitic, and stearic acids (i.e. 11-dodecynoic, 15-hexadecynoic, and 17-octadecynoic acids). Consistent with a suicidal process, inactivation of the LTB4 omega-hydroxylase requires molecular oxygen and NADPH, is time-dependent, and follows pseudo-first-order kinetics. Inactivation of the omega-hydroxylase by acetylenic fatty acids also is dependent on the terminal acetylenic moiety and the carbon chain length. Saturated fatty acids lacking a terminal acetylenic moiety do not inactivate the omega-hydroxylase. In addition, the two long-chain (C16, C18) acetylenic fatty acids inactivate the omega-hydroxylase at much lower concentrations (less than 5.0 microM) than those required for inactivation by the short-chain (C12) terminal acetylenic fatty acid (100 microM). Potent suicidal inhibitors of the LTB4 omega-hydroxylase in human PMN will help elucidate the roles played by LTB4 and its omega-oxidation products in regulating PMN function and in mediating inflammation.

  20. Mechanism-based inactivation of benzo[a]pyrene hydroxylase by aryl acetylenes and aryl olefins

    International Nuclear Information System (INIS)

    Gan, L.S.; Lu, J.Y.L.; Alworth, W.L.

    1986-01-01

    A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxgenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene, 3-ethynylperylene, 2-ethynylfluorene, methyl 1-pyrenyl acetylene, cis- and trans-1-(2-bromovinyl)pyrene, and 1-allylpyrene serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo[a]pyrene hydroxylase, while 1-vinylpyrene and phenyl 1-pyrenyl acetylene do not cause a detectable suicide inhibition of benzo[a]pyrene hydroxylase. The mechanism-based loss of benzo[a]pyrene hydroxylase caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes (suicide destruction). The suicide inhibition by these aryl acetylenes therefore does not involve covalent binding to the heme moiety of the monooxygenase. Nevertheless, in the presence of NADPH, 3 H-labeled 1-ethynylpyrene becomes covalently attached to the cytochrome P-450 protein; the measured stoichiometry of binding is one 1-ethynylpyrene per P-450 heme unit. The authors conclude that the inhibition of benzo[a]pyrene hydroxylase produced by 1-ethynylpyrene may be related to the mechanism of suicide inhibition of P-450 activity by chloramphenicol rather than the mechanism of suicide destruction of P-450 previously described for acetylene and propyne

  1. Stability improvement of the Nieuwland catalyst in the dimerization of acetylene to monovinylacetylene

    Institute of Scientific and Technical Information of China (English)

    Jianguo Liu; Yizan Zuo; Minghan Han; Zhanwen Wang; Dezheng Wang

    2012-01-01

    In the process of dimerization of acetylene to produce monovinylacetylene (MVA),the loss of active component CuCl in the Nieuwland catalyst due to the formation of a dark red precipitate was investigated.The formula of the precipitate was CuCl·2C2H2·1/5NH3,and it was presumed to be formed by the combination of NH3,C2H2 and [Cu]-acetylene π-complex,which was an intermediate in the dimerization reaction.The addition of hydrochloric acid into the catalyst can reduce the formation of precipitate,whereas excessive H+ is unfavorable to the dimerization reaction of acetylene.To balance between high acetylene conversion and low loss rate of CuCl,the optimum mass percentage of HCl in the added hydrochloric acid was determined.The result showed the optimum mass percentage of HCl decreased from 5.0% to 3.2% when the space velocity of acetylene was from 140 h-1 to 360 h-1.The result in this work also indicated the pH of the Nieuwland catalyst should be kept in the range of 5.80-5.97 during the reaction process,which was good for both catalyst life and acetylene conversion.

  2. Disposition and biotransformation of the acetylenic retinoid tazarotene in humans.

    Science.gov (United States)

    Attar, Mayssa; Yu, Dale; Ni, Jinsong; Yu, Zhiling; Ling, Kah-Hiing John; Tang-Liu, Diane D-S

    2005-10-01

    Oral tazarotene, an acetylenic retinoid, is in clinical development for the treatment of psoriasis. The disposition and biotransformation of tazarotene were investigated in six healthy male volunteers, following a single oral administration of a 6 mg (100 microCi) dose of [14C]tazarotene, in a gelatin capsule. Blood levels of radioactivity peaked 2 h postdose and then rapidly declined. Total recovery of radioactivity was 89.2+/-8.0% of the administered dose, with 26.1+/-4.2% in urine and 63.0+/-7.0% in feces, within 7 days of dosing. Only tazarotenic acid, the principle active metabolite formed via esterase hydrolysis of tazarotene, was detected in blood. One major urinary oxidative metabolite, tazarotenic acid sulfoxide, accounted for 19.2+/-3.0% of the dose. The majority of radioactivity recovered in the feces was attributed to tazarotenic acid representing 46.9+/-9.9% of the dose and only 5.82+/-3.84% of dose was excreted as unchanged tazarotene. Thus following oral administration, tazarotene was rapidly absorbed and underwent extensive hydrolysis to tazarotenic acid, the major circulating species in the blood that was then excreted unchanged in feces. A smaller fraction of tazarotenic acid was further metabolized to an inactive sulfoxide that was excreted in the urine. Copyright (c) 2005 Wiley-Liss, Inc. and the American Pharmacists Association

  3. Spectroscopy of vibrationally hot molecules: Hydrogen cyanide and acetylene

    International Nuclear Information System (INIS)

    Jonas, D.M.

    1992-01-01

    An efficient formula for calculating nuclear spin statistical weights is presented. New experimental methods to distinguish electric and magnetic multipole transitions are proposed and used to prove that the formaldehyde A - X 0-0 transition is a magnetic dipole transition. HIgh resolution vacuum ultraviolet studies of the A → X fluorescence excitation spectrum of hydrogen cyanide (HCN) have: (i) determined that only the (0,1,0) vibrational level of the HCN A-state has a sufficiently long fluorescence lifetime to be suitable for Stimulated Emission Pumping (SEP) studies; and (ii) measured the electric dipole moment of the A-state. Several transitions in the hydrogen cyanide A → X SEP spectrum are shown to be due to the axis-switching mechanism. From a Franck-Condon plot of the intensities and a comparison between sums of predicted rotational constants and sums of observed rotational constants, all of the remaining transitions in the SEP spectrum can be securly assigned. Two weak resonances; a 2:3 CH:CN stretch Fermi resonance and a 6:2 bend:CN stretch resonance appear in the SEP spectrum. Excitation of the CH stretching vibration is predicted and shown to be entirely absent, apart from resonances, in the HCN SEP spectrum. A → X SEP spectra of acetylene (HCCH) near E VIB = 7,000 cm -1 display a wealth of strong and fully assignable anharmonic resonances and forbidden rotational transitions. It is proved that Darling-Dennison resonance between the cis and trans bending vibrations is the crucial first step in a series of anharmonic resonances which can transfer nearly all the vibrational energy out of the initial CC stretch/trans-bend excitation at high vibrational energy. Secondary steps in the vibrational energy flow are vibrational-l-resonance and the '2345' Fermi resonance. For short times, the vibrational energy redistribution obeys very restrictive rules

  4. Experimental investigation on dual fuel operation of acetylene in a DI diesel engine

    Energy Technology Data Exchange (ETDEWEB)

    Lakshmanan, T. [Department of Mechanical Engineering, Rajarajeswari Engineering College, Adayalampattu, Chennai, 600095 (India); Nagarajan, G. [Internal Combustion Engineering Division, College of Engineering, Anna University, Chennai, 600025 (India)

    2010-05-15

    Depletion of fossils fuels and environmental degradation have prompted researchers throughout the world to search for a suitable alternative fuel for diesel engine. One such step is to utilize renewable fuels in diesel engines by partial or total replacement of diesel in dual fuel mode. In this study, acetylene gas has been considered as an alternative fuel for compression ignition engine, which has excellent combustion properties. Investigation has been carried out on a single cylinder, air cooled, direct injection (DI), compression ignition engine designed to develop the rated power output of 4.4 kW at 1500 rpm under variable load conditions, run on dual fuel mode with diesel as injected primary fuel and acetylene inducted as secondary gaseous fuel at various flow rates. Acetylene aspiration resulted in lower thermal efficiency. Smoke, HC and CO emissions reduced, when compared with baseline diesel operation. With acetylene induction, due to high combustion rates, NO{sub x} emission significantly increased. Peak pressure and maximum rate of pressure rise also increased in the dual fuel mode of operation due to higher flame speed. It is concluded that induction of acetylene can significantly reduce smoke, CO and HC emissions with a small penalty on efficiency. (author)

  5. Morphological reason for enhancement of electrochemical double layer capacitances of various acetylene blacks by electrochemical polarization

    International Nuclear Information System (INIS)

    Kim, Taegon; Ham, Chulho; Rhee, Choong Kyun; Yoon, Seong-Ho; Tsuji, Masaharu; Mochida, Isao

    2008-01-01

    Enhancement of electrochemical capacitance and morphological variations of various acetylene blacks caused by electrochemical polarization are presented. Acetylene blacks of different mean particle diameters were modified by air-oxidation and heat treatment to diversify the morphologies of the acetylene blacks before electrochemical polarization. The various acetylene blacks were electrochemically oxidized at 1.6 V (vs. Ag/AgCl) for 10 s and the polarization step was repeated until the capacitance values did not change any longer. These polarization steps enhanced the capacitances of the acetylene blacks and the specific enhancement factors range from 2 to 5.5. Such an enhancement is strongly related to morphological modification as revealed by transmission electron microscopic observations. The electrochemical polarization resulted in formation of tiny graphene sheets on the wide graphitic carbon surfaces, which were most responsible for the observed capacitive enhancement. Although the pseudo-capacitance increased after polarization by forming oxygenated species on the surfaces, its contribution to the total capacitance was less than 10%. The mechanism of the formation of the tiny graphene sheets during the electrochemical oxidation is described schematically

  6. The Preparation of Cu-g-C3N4/AC Catalyst for Acetylene Hydrochlorination

    Directory of Open Access Journals (Sweden)

    Wenli Zhao

    2016-12-01

    Full Text Available A novel catalyst based on g-C3N4/activated carbon was prepared by adding CuCl2. The catalytic performance of the as-prepared catalyst was investigated in the acetylene hydrochlorination reaction. X-ray photoelectron spectroscopy, temperature programmed desorption, low temperature N2 adsorption/desorption (Brunauer–Emmett–Teller, and thermal gravity analysis showed that Cu-g-C3N4/AC significantly enhanced the catalytic performance of the original catalyst by increasing the relative pyrrolic N content. Cu-g-C3N4/AC also affected the adsorption of hydrogen chloride and acetylene, as well as inhibited the coke deposition during acetylene hydrochlorination.

  7. Modeling, simulation, and optimization of a front-end system for acetylene hydrogenation reactors

    Directory of Open Access Journals (Sweden)

    R. Gobbo

    2004-12-01

    Full Text Available The modeling, simulation, and dynamic optimization of an industrial reaction system for acetylene hydrogenation are discussed in the present work. The process consists of three adiabatic fixed-bed reactors, in series, with interstage cooling. These reactors are located after the compression and the caustic scrubbing sections of an ethylene plant, characterizing a front-end system; in contrast to the tail-end system where the reactors are placed after the de-ethanizer unit. The acetylene conversion and selectivity profiles for the reactors are optimized, taking into account catalyst deactivation and process constraints. A dynamic optimal temperature profile that maximizes ethylene production and meets product specifications is obtained by controlling the feed and intercoolers temperatures. An industrial acetylene hydrogenation system is used to provide the necessary data to adjust kinetics and transport parameters and to validate the approach.

  8. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of

  9. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    NARCIS (Netherlands)

    Kester, R.A.; De Boer, W.; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous

  10. Estimation of nitrogenase activity in the presence of ethylene biosynthesis by use of deuterated acetylene as a substrate

    International Nuclear Information System (INIS)

    Lin-Vien, D.; Fateley, W.G.; Davis, L.C.

    1989-01-01

    Nitrogenase reduces deuterated acetylene primarily to cis dideuterated ethylene. This can be distinguished from undeuterated ethylene by the use of Fourier transform infrared spectroscopy. Characteristic bands in the region from 800 to 3,500 cm-1 can be used to identify and quantitate levels of these products. This technique is applicable to field studies of nitrogen fixation where ethylene biosynthesis by plants or bacteria is occurring. We have verified the reaction stoichiometry by using Klebsiella pneumoniae and Bradyrhizobium japonicum in soybeans. The most useful bands for quantitation of substrate purity and product distribution are as follows: acetylene-d0, 3,374 cm-1; acetylene-d1, 2,584 cm-1; acetylene-d2, 2,439 cm-1; cis-ethylene-d2, 843 cm-1; trans-ethylene-d2, 988 cm-1; ethylene-d1, 943 cm-1; ethylene-d0, 949 cm-1. (The various deuterated ethylenes and acetylenes are designated by a lowercase d and subscript to indicate the number, but not the position, of deuterium atoms in the molecule.) Mass spectrometry coupled to a gas chromatograph system has been used to assist in quantitation of the substrate and product distributions. Significant amounts of trans-ethylene-d2 were produced by both wild-type and nifV mutant K. pneumoniae. Less of this product was observed with the soybean system

  11. Acetylenes bearing Aromatic Terminal Groups. : II 13C-NMR Spectra of Monosubstituted Diphenylacetylenes

    OpenAIRE

    野本, 健雄; Nomoto, Takeo

    1986-01-01

    Six monosubstituted diphenylacetylenes, p-X-C6H4-C≡C-C6H5 1 (Ⅹ=NMe2, NH2, OMe, Cl, and NO2), were synthesized, and 13C-NMR spectra of their acetylenic carbons were measured. Hammett plots of the chemical shifts of the acetylenic α-13C and β-13C (against substituent constants σ) respectively showed a linear relationship, eXCept for β-13C on NMe2 and NH2 groups. The effects of substituents on 13C-Chemical shifts of diphenylacetylenes and effeciency of the C≡C bonds in transmitting the substitue...

  12. Synthesis of micro- and nanodiamonds by the method of oxy- acetylene combustion flame

    International Nuclear Information System (INIS)

    Sabitov, S; Medyanova, B; Partizan, G; Koshanova, A; Mansurova, M; Lesbayev, B; Mansurov, B; Merkibayev, Ye

    2016-01-01

    This work presents the results of experiments on synthesis of micro- and nanodiamonds by the method of oxy-acetylene torch on the surface of pre-deposited copper thin films. The influence of the thickness of the buffer copper film and the concentration ratio of oxygen and acetylene on the structure formation of the deposited samples was investigated during performed experiments. Studies by Raman scattering and scanning electron microscopy showed that the synthesis of micro- and nano-diamonds occurs under certain experimental conditions. (paper)

  13. Heats of Formation of Triplet Ethylene, Ethylidene, and Acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Nguyen, M.T.; Matus, M.H.; Lester Jr, W.A.; Dixon, David A.

    2007-06-28

    Heats of formation of the lowest triplet state of ethylene and the ground triplet state of ethylidene have been predicted by high level electronic structure calculations. Total atomization energies obtained from coupled-cluster CCSD(T) energies extrapolated to the complete basis set limit using correlation consistent basis sets (CBS), plus additional corrections predict the following heats of formation in kcal/mol: Delta H0f(C2H4,3A1) = 80.1 at 0 K and 78.5 at 298 K, and Delta H0f(CH3CH,3A") = 86.8 at 0 K and 85.1 at 298 K, with an error of less than +-1.0 kcal/mol. The vertical and adiabatic singlet-triplet separation energies of ethylene were calculated as Delta ES-T,vert = 104.1 and Delta ES-T,adia = 65.8 kcal/mol. These results are in excellent agreement with recent quantum Monte Carlo (DMC) values of 103.5 +- 0.3 and 66.4 +- 0.3 kcal/mol. Both sets of computational values differ from the experimental estimate of 58 +- 3 kcal/mol for the adiabatic splitting. The computed singlet-triplet gap at 0 K for acetylene is Delta ES-T,adia(C2H2) = 90.5 kcal/mol, which is in notable disagreement with the experimental value of 82.6 kcal/mol. The heat of formation of the triplet is Delta H0f(C2H2,3B2) = 145.3 kcal/mol. There is a systematic underestimation of the singlet-triplet gaps in recent photodecomposition experiments by ~;;7 to 8 kcal/mol. For vinylidene, we predict Delta H0f(H2CC,1A1) = 98.8 kcal/mol at 298 K (exptl. 100.3 +- 4.0), Delta H0f(H2CC,3B2) = 146.2 at 298 K, and an energy gap Delta ES-T-adia(H2CC) = 47.7 kcal/mol.

  14. Control of the nucleation and quality of graphene grown by low-pressure chemical vapor deposition with acetylene

    International Nuclear Information System (INIS)

    Yang, Meng; Sasaki, Shinichirou; Suzuki, Ken; Miura, Hideo

    2016-01-01

    Graphical abstract: - Highlights: • For the first time, we succeeded in the LPCVD growth of monolayer graphene using acetylene as the precursor gas. • The growth rate is very high when acetylene is used as the source gas. Our process has exhibited the potential to shorten the growth time of CVD graphene. • We found that the domain size, defects density, layer number and the sheet resistance of graphene can be changed by changing the acetylene flow rates. • We found that it is also possible to form bilayer graphene using acetylene. However, further study are necessary to reduce the defects density. - Abstract: Although many studies have reported the chemical vapor deposition (CVD) growth of large-area monolayer graphene from methane, synthesis of graphene using acetylene as the source gas has not been fully explored. In this study, the low-pressure CVD (LPCVD) growth of graphene from acetylene was systematically investigated. We succeeded in regulating the domain size, defects density, layer number and the sheet resistance of graphene by changing the acetylene flow rates. Scanning electron microscopy and Raman spectroscopy were employed to confirm the layer number, uniformity and quality of the graphene films. It is found that a low flow rate of acetylene (0.28 sccm) is required to form high-quality monolayer graphene in our system. On the other hand, the high acetylene flow rate (7 sccm) will induce the growth of the bilayer graphene domains with high defects density. On the basis of selected area electron diffraction (SAED) pattern, the as-grown monolayer graphene domains were analyzed to be polycrystal. We also discussed the relation between the sheet resistacne and defects density in graphene. Our results provide great insights into the understanding of the CVD growth of monolayer and bilayer graphene from acetylene.

  15. Control of the nucleation and quality of graphene grown by low-pressure chemical vapor deposition with acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Meng, E-mail: youmou@rift.mech.tohoku.ac.jp [Department of Nanomechanics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Sasaki, Shinichirou [Department of Nanomechanics, Graduate School of Engineering, Tohoku University, Sendai 980-8579 (Japan); Suzuki, Ken; Miura, Hideo [Fracture and Reliability Research Institute, Tohoku University, Sendai 980-8579 (Japan)

    2016-03-15

    Graphical abstract: - Highlights: • For the first time, we succeeded in the LPCVD growth of monolayer graphene using acetylene as the precursor gas. • The growth rate is very high when acetylene is used as the source gas. Our process has exhibited the potential to shorten the growth time of CVD graphene. • We found that the domain size, defects density, layer number and the sheet resistance of graphene can be changed by changing the acetylene flow rates. • We found that it is also possible to form bilayer graphene using acetylene. However, further study are necessary to reduce the defects density. - Abstract: Although many studies have reported the chemical vapor deposition (CVD) growth of large-area monolayer graphene from methane, synthesis of graphene using acetylene as the source gas has not been fully explored. In this study, the low-pressure CVD (LPCVD) growth of graphene from acetylene was systematically investigated. We succeeded in regulating the domain size, defects density, layer number and the sheet resistance of graphene by changing the acetylene flow rates. Scanning electron microscopy and Raman spectroscopy were employed to confirm the layer number, uniformity and quality of the graphene films. It is found that a low flow rate of acetylene (0.28 sccm) is required to form high-quality monolayer graphene in our system. On the other hand, the high acetylene flow rate (7 sccm) will induce the growth of the bilayer graphene domains with high defects density. On the basis of selected area electron diffraction (SAED) pattern, the as-grown monolayer graphene domains were analyzed to be polycrystal. We also discussed the relation between the sheet resistacne and defects density in graphene. Our results provide great insights into the understanding of the CVD growth of monolayer and bilayer graphene from acetylene.

  16. Synthesis of trifluoromethylated acetylenes via copper-catalyzed trifluoromethylation of alkynyltrifluoroborates

    KAUST Repository

    Zheng, Huidong

    2012-12-01

    A new method for the synthesis of trifluoromethylated acetylenes is developed which involves the copper-catalyzed trifluoromethylation of alkynyltrifluoroborates with an electrophilic trifluoromethylating reagent. This method offers significant advantages such as efficiency and mild and base-free reaction conditions. A plausible mechanism is proposed. © 2012 Elsevier Ltd. All rights reserved.

  17. On the Role of Surface Modifications of Palladium Catalysts in the Selective Hydrogenation of Acetylene

    DEFF Research Database (Denmark)

    Studt, Felix; Abild-Pedersen, Frank; Bligaard, Thomas

    2008-01-01

    Summing Me up: DFT calculations have shown that alloying, subsurface carbon, and hydride formation, all increase the selectivity of Pd catalysts for acetylene hydrogenation by weakening the surface–adsorbate bond. A simple descriptor—the adsorption energy of a methyl group—has been used to quanti...

  18. Association Mechanisms of Unsaturated C2 Hydrocarbons with Their Cations: Acetylene and Ethylene

    Science.gov (United States)

    Bera, Partha P.; Head-Gordon, Martin; Lee, Timothy J.

    2013-01-01

    The ion-molecule association mechanism of acetylene and ethylene with their cations is investigated by ab initio quantum chemical methods to understand the structures, association energies, and the vibrational and electronic spectra of the products. Stable puckered cyclic isomers are found as the result of first forming less stable linear and bridge isomers. The puckered cyclic complexes are calculated to be strongly bound, by 87, 35 and 56 kcal/mol for acetylene-acetylene cation, ethylene-ethylene cation and acetylene-ethylene cation, respectively. These stable complexes may be intermediates that participate in further association reactions. There are no association barriers, and no significant inter-conversion barriers, so the initial linear and bridge encounter complexes are unlikely to be observable. However, the energy gap between the bridged and cyclic puckered isomers greatly differs from complex to complex: it is 44 kcal/mol in C4H4 +, but only 6 kcal/mol in C4H8 +. The accurate CCSD(T) calculations summarized above are also compared against less computationally expensive MP2 and density functional theory (DFT) calculations for structures, relative energies, and vibrational spectra. Calculated vibrational spectra are compared against available experiments for cyclobutadiene cation. Electronic spectra are also calculated using time-dependent DFT.

  19. Nine acetylenic alcohols isolated from the Okinawan marine sponge of the genus Petrosia (Strongylophora).

    NARCIS (Netherlands)

    Watanabe, K.; Mori, G.; Iguchi, K.; Suzuki, M.; van Soest, R.W.M.

    2007-01-01

    Nine new acetylenic alcohols 1-9 were isolated from a marine sponge belonging to the genus Petrosia (Strongylophora). The structures were elucidated mainly based on the analysis of one-and two-dimensional NMR spectral data. To determine the position of the central double bonds in 1-8, each compound

  20. Conductance mechanism in a linear non-conjugated trimethylsilyl-acetylene molecule: tunneling through localized states

    NARCIS (Netherlands)

    Petrov, E.G.; Marchenko, A.; Kapitanchuk, O.; Katsonis, Nathalie Hélène; Fichou, D.

    2014-01-01

    The conductance properties of 1,3-(trimethylsilyl)-1-tridecene-6,12-diyne, a non-conjugated trimethylsil-acetylene molecule have been investigated both experimentally and theoretically. Based on scanning tunnelling spectroscopy experiments, a discussion on the mechanisms controlling the charge

  1. A Convenient Synthesis of Conjugated Acetylenic Ketones by Copper(l)-Catalyzed under Microwave Irradiation

    Institute of Scientific and Technical Information of China (English)

    WANG; JinXian

    2001-01-01

    Alkynyl ketones are useful precursors and intermediates in synthetic organic chemistry1 and has evoked considerable interest. A number of methods for the synthesis of conjugated acetylenic ketones involve the reaction a metal acetylide with an acyl chlorides or another carboxylic acid derivative have been developed 2. Recently, the synthesis of α, β-conjugated acetylenic ketones catalyzed by Pd(Ⅱ) or by copper(Ⅰ)pd(Ⅱ) reaction of 1-alkynes and acyl chlorides have been described. The acylation of terminal alkynes by acyl chlorides in the presence of catalytic amounts copper(Ⅰ) salts leading to α, β-conjugated acetylenic ketones has also been reported. However, many of these reactions suffer from lack of high pressure (17 atm), long reaction time (30 h)and require low temperatures (-78℃). Our work involves the synthesis of conjugated acetylenic ketones via the reaction of terminal alkynes with aroyl chlorides in the presence of cuprous iodide under microwave irradiation conditions.……

  2. Matrix Isolation and ab initio study of the noncovalent complexes between formamide and acetylene.

    Science.gov (United States)

    Mardyukov, Artur; Sánchez-García, Elsa; Sander, Wolfram

    2009-02-12

    Matrix isolation spectroscopy in combination with ab initio calculations is a powerful technique for the identification of weakly bound intermolecular complexes. Here, weak complexes between formamide and acetylene are studied, and three 1:1 complexes with binding energies of -2.96, -2.46, and -1.79 kcal/mol have been found at the MP2 level of theory (MP2/cc-pVTZ + ZPE + BSSE). The two most stable dimers A and B are identified in argon and nitrogen matrices by comparison between the experimental and calculated infrared frequencies. Both complexes are stabilized by the formamide C=O...HC acetylene and H...pi interactions. Large shifts have been observed experimentally for the C-H stretching vibrations of the acetylene molecule, in very good agreement with the calculated values. Eight 1:2 FMA-acetylene trimers (T-A to T-H) with binding energies between -5.44 and -2.62 kcal/mol (MP2/aug-cc-pVDZ + ZPE + BSSE) were calculated. The two most stable trimers T-A and T-B are very close in energy and have similar infrared spectra. Several weak bands that are in agreement with the calculated frequencies of the trimers T-A and T-B are observed under matrix isolation conditions. However, the differences are too small for a definitive assignment.

  3. Synthesis of acetylene alcohols of heterocyclic type and the acyl derivatives

    Directory of Open Access Journals (Sweden)

    Moldir Dyusebaeva

    2015-03-01

    Full Text Available A synthesis of potentially biologically active heterocyclic amino alcohols of acetylene (Piperidine and Morpholine under the conditions of Mannich reaction accomplished and received their acyl derivatives. Pharmacological activity (antibacterial and antispasmotic of synthesized compounds, also acute toxicological characteristics studied. The study showed that the combination of DMAE-4 has antispasmodic activity with low toxicity.

  4. Interference in acetylene intersystem crossing acts as the molecular analog of Young's double-slit experiment

    NARCIS (Netherlands)

    de Groot, M.; Field, R.W.; Buma, W.J.

    2009-01-01

    We report on an experimental approach that reveals crucial details of the composition of singlet-triplet mixed eigenstates in acetylene. Intersystem crossing in this prototypical polyatomic molecule embodies the mixing of the lowest excited singlet state (S1) with 3 triplet states (T1, T2, and T3).

  5. Reactivity differences of Pt0 phosphine complexes in C-C bond activation of asymmetric acetylenes

    NARCIS (Netherlands)

    Gunay, A.; Müller, C.; Lachicotte, R.J.; Brennessel, W.W.; Jones, W.D.

    2009-01-01

    Carbon-carbon bond activation reactions of asymmetric acetylene derivatives of the type L2Pt(PhC=CR) were studied with 1,2-bis(diisopropylphosphino)ethane (dippe), 1,2-bis(di-tert-butylphosphino)ethane (dtbpe), and 1-diisopropylphosphino-2-dimethylaminoethane (dippdmae) chelates.

  6. Synthesis of trifluoromethylated acetylenes via copper-catalyzed trifluoromethylation of alkynyltrifluoroborates

    KAUST Repository

    Zheng, Huidong; Huang, Yuanyuan; Wang, Zhiwei; Li, Huaifeng; Huang, Kuo-Wei; Yuan, Yaofeng; Weng, Zhiqiang

    2012-01-01

    A new method for the synthesis of trifluoromethylated acetylenes is developed which involves the copper-catalyzed trifluoromethylation of alkynyltrifluoroborates with an electrophilic trifluoromethylating reagent. This method offers significant advantages such as efficiency and mild and base-free reaction conditions. A plausible mechanism is proposed. © 2012 Elsevier Ltd. All rights reserved.

  7. Influence of soil composition in the determination of chromium by atomic absorption spectrometry with flame air / acetylene

    International Nuclear Information System (INIS)

    Duran Sosa, Ibis; Granda Valdes, Mayra; Pomares Alfonso, Mario Simeon

    2014-01-01

    The Air-acetylene Flame Atomic Absorption determination of chromium is a complex task, being strongly influenced by sample composition and instrumental conditions. The objective of this work was to study the influence of Al, Ca, Fe, K, Mg, and Na on the absorption of chromium in the air-acetylene flame, both separately and combined in solution, when acetylene flow and burner height vary. Dissolutions of the mixtures simulated the composition of four soils from the Quibu River Basin in Havana, Cuba. Chromium absorption first increased and then decreased with increment of acetylene flow for shorter burner heights (∼ 2-4 mm); while a continuous increase was observed for larger heights (> 4 mm). This behavior was the same in the presence and absence of interfering chemical element, mentioned above. On the other hand, the dependence of the magnitude of the interference with acetylene flow and burner height was complex and dependent on the interfering element, particularly at larger heights where the behavior of Al was remarkably different. The interference of the four mixtures of Al, Ca, K, Fe, Mg and Na decreased in comparison to individual interfering effects and was less dependent on acetylene flow and burner height. Finally, a significant reduction of interference on chromium determination in soil samples was achieved by an adequate selection of acetylene flow and burner height

  8. Facile synthesis and electrochemical performances of binder-free flexible graphene/acetylene black sandwich film

    International Nuclear Information System (INIS)

    Xu, Juan; Wei, Xicheng; Cao, Jianyu; Dong, Yuanzhu; Wang, Guoxin; Xue, Yufei; Wang, Wenchang; Chen, Zhidong

    2015-01-01

    Graphene/acetylene black sandwich film was fabricated by a simple vacuum filtration procedure using a stable complex suspension of graphene oxide (GO) and acetylene black followed by a hydroiodic acid (HI) immersion process to fully reduce the GO to graphene sheets. The self-restacking of individual graphene sheets were greatly alleviated and electric conductivity was obviously improved using the acetylene black nanoparticles as both effective spacers to expand the inter-layer interval of the individual graphene sheets during the film assembly course and highly conducting bridges to facilitate the electron/ion transfer between the upper and lower graphene sheets. The flexible graphene/acetylene black film was utilized as supercapacitor electrode without additional conductive additives, binders and current collectors, which achieved an obviously higher specific capacitance (ca. 136.6 F g −1 at 0.5 A g −1 ) and much better specific capacitance retention at high current densities than that of the pure graphene film electrode, indicating that such a novel sandwich film structure allows for a higher charge storage capability. More importantly, the assembled symmetric supercapacitor device displayed a satisfactory specific capacitance of 59.2 F g −1 at 0.1 A g −1 , 47.6 F g −1 at 0.5 A g −1 and 42.8 F g −1 at 1 A g −1 , and only negligible 4.05% capacitance degradation have been found after 1000 continuous charge-discharge cycles at 0.5 A g −1 , revealing outstanding rate capability, excellent electrochemical reversibility and long-term cyclability. These results proved that such a flexible and highly conductive graphene/acetylene black film can be promising electroactive materials in the development of advanced electrochemical energy storage devices

  9. Study on using acetylene in dual fuel mode with exhaust gas recirculation

    International Nuclear Information System (INIS)

    Lakshmanan, T.; Nagarajan, G.

    2011-01-01

    Interest in employing gaseous fuels to internal combustion (IC) engines whether for stationary or mobile automotive applications has gained importance because of the economical, sustainable and environmental technical features associated with their usage. However, the incidence of preignition and knock remains a significant barrier in achieving their optimum performance potential. With the advent of latest technologies, the above barriers are eliminated. One such technique is timed manifold injection (TMI) of the gaseous fuel, which is controlled electronically to precisely monitor the induction of fuel to overcome the preignition problem in the intake. In the present investigation, acetylene was injected in the intake manifold in a single cylinder diesel engine, with a gas flow rate of 240 g/h, start of injection time is 10 o aTDC and 90 o CA (9.9 ms) duration, operated in dual fuel mode. In order to decrease the NOx emissions from acetylene-diesel engine, cooled EGR was employed. The cylinder pressure, brake thermal efficiency and emissions such as NOx, smoke, CO, HC, CO 2 and exhaust gas temperature were studied. Dual fuel operation with acetylene induction coupled with cooled EGR results in lowered NOx emissions and improved part load performance. -- Highlights: → Acetylene was tried in SI engines, but due to backfire further research was hindered as an alternative fuel. → But it is not tried in CI engine. Timed manifold injection was tried in diesel engine in the present work to combat backfire. → Author was successful in running the diesel engine in dual fuel mode. → 21% maximum diesel replacement was achieved. Author is confident that acetylene will be commercialised as a fuel for diesel engine in future.

  10. Ab initio and matrix isolation study of the acetylene-furan dimer

    International Nuclear Information System (INIS)

    Sanchez-Garcia, Elsa; Mardyukov, Artur; Tekin, Adem; Crespo-Otero, Rachel; Montero, Luis A.; Sander, Wolfram; Jansen, Georg

    2008-01-01

    Five acetylene-furan dimer structures are identified using ab initio calculations at the second-order Moller-Plesset (MP2) level of theory. The structures are stabilized by two basic types of intermolecular interactions: the CH...O and the CH...π interaction. The CH...π interaction appears in two variants, depending on which molecule provides the hydrogen atom and which molecule the π system. The MP2 results indicate that the CH...π interaction between one of the hydrogen atoms of acetylene and the π system of furan as found in structure A is the strongest interaction, followed by the in-plane CH...O interaction in the second most stable acetylene-furan dimer structure B. A matrix isolation study shows the acetylene-furan dimer to exist in an argon matrix, but likely rather as structure B than as A. High level coupled cluster calculations with up to triple excitations (CCSD(T)) yield the interaction energy of structure A as about -2.4 kcal/mol in the complete basis set limit and find structure B to be nearly isoenergetic with -2.3 kcal/mol. This is confirmed in calculations employing the density functional theory combined with symmetry adapted intermolecular perturbation theory (DFT-SAPT) approach yielding interaction energies of -2.3 and -2.0 kcal/mol for A and B, respectively. DFT-SAPT also helps to understand the importance of the electrostatic, induction and dispersion interaction energies and their respective exchange counterparts for the stability of the various acetylene-furan dimer structures. The CH...O and CH...π interactions are furthermore analyzed with the help of the atoms in molecules (AIM) theory

  11. Purification and characterization of acetylene hydratase of Pelobacter acetylenicus, a tungsten iron-sulfur protein.

    Science.gov (United States)

    Rosner, B M; Schink, B

    1995-10-01

    Acetylene hydratase of the mesophilic fermenting bacterium Pelobacter acetylenicus catalyzes the hydration of acetylene to acetaldehyde. Growth of P. acetylenicus with acetylene and specific acetylene hydratase activity depended on tungstate or, to a lower degree, molybdate supply in the medium. The specific enzyme activity in cell extract was highest after growth in the presence of tungstate. Enzyme activity was stable even after prolonged storage of the cell extract or of the purified protein under air. However, enzyme activity could be measured only in the presence of a strong reducing agent such as titanium(III) citrate or dithionite. The enzyme was purified 240-fold by ammonium sulfate precipitation, anion-exchange chromatography, size exclusion chromatography, and a second anion-exchange chromatography step, with a yield of 36%. The protein was a monomer with an apparent molecular mass of 73 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was at pH 4.2. Per mol of enzyme, 4.8 mol of iron, 3.9 mol of acid-labile sulfur, and 0.4 mol of tungsten, but no molybdenum, were detected. The Km for acetylene as assayed in a coupled photometric test with yeast alcohol dehydrogenase and NADH was 14 microM, and the Vmax was 69 mumol.min-1.mg of protein-1. The optimum temperature for activity was 50 degrees C, and the apparent pH optimum was 6.0 to 6.5. The N-terminal amino acid sequence gave no indication of resemblance to any enzyme protein described so far.

  12. Short exposure to acetylene to distinguish between nitrifier and denitrifier nitrous oxide production in soil and sediment samples

    OpenAIRE

    Kester, R.A.; Boer, W. de; Laanbroek, H.J.

    1996-01-01

    The contribution of nitrifiers and denitrifiers to the nitrous oxide production in slurries of calcareous silt loam and river bank sediment at different oxygen concentrations was determined using acetylene as nitrification inhibitor. The addition of 10 Pa acetylene resulted in inhibition of nitrous oxide production at oxic conditions, but strongly enhanced the nitrous oxide production at oxygen-poor and anoxic conditions. Inhibition of nitrification by short exposure (1 to 24 h) to high conce...

  13. New 2-Methoxy Acetylenic Acids and Pyrazole Alkaloids from the Marine Sponge Cinachyrella sp.

    Directory of Open Access Journals (Sweden)

    Amin Mokhlesi

    2017-11-01

    Full Text Available Three new 2-methoxy acetylenic acids (1–3 and a known derivative (4, in addition to three new natural pyrazole alkaloids (5–7 were isolated from an Indonesian marine sponge of the genus Cinachyrella. Compounds 5 and 6 have previously been reported as synthetic compounds. The structures of the new compounds were established on the basis of one- and two-dimensional NMR spectroscopy as well as by mass spectrometric data. The absolute configuration of the new acetylenic acid derivatives (1–3 was established by ECD spectroscopy. All isolated compounds were evaluated for their cytotoxicity against L5178Y mouse lymphoma cells. Compounds 1–4 exhibited strong activity with an IC50 value of 0.3 µM. A plausible biosynthetic pathway for the pyrazole metabolites 5–7 is proposed.

  14. Synthesis and kinetics of non-isothermal degradation of acetylene terminated silazane

    Institute of Scientific and Technical Information of China (English)

    Wei Jian Han; Li Ye; Ji Dong Hu; Tong Zhao

    2011-01-01

    Novel acetylene terminated silazane compounds, with three types of substituent, were synthesized by the aminolysis of dichlorosilane with 3-aminophenylacetylene (3-APA). Thermal property of the compounds is studied by thermogravimetry analysis (TGA). It shows that the acetylene terminated silazane has high temperature resistance. The char yield at 1000℃ is 77.6, 81.9 and 68.7 wt% for methyl, vinyl, and phenyl substituted silazane, respectively. The pyrolysis kinetics of the silazane is investigated by non-isothermal thermogravimetric measurement. The pyrolysis undergoes three stages, which is resolved by PEAKFIT. The kinetic parameters are calculated by the Kissinger method. The role of functionalities on the thermal resistance is discussed. The vinyl-silazane exhibits higher thermal stability because of higher cross-linking density.

  15. Solid-State Polymerization of Acetylene under Pressure: {ital Ab Initio} Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Bernasconi, M.; Parrinello, M. [Max-Planck-Institut fuer Festkoerperforschung, Heisenbergstr.1, D-70569 Stuttgart (Germany); Bernasconi, M. [Istituto Nazionale Fisica della Materia and Dipartimento di Fisica, Universita di Milano, Via Celoria 16, 20133 Milano (Italy); Chiarotti, G.; Focher, P.; Tosatti, E. [Istituto Nazionale Fisica della Materia and International School for Advanced Studies, Via Beirut 4, I-34014 Trieste (Italy); Tosatti, E. [International Centre for Theoretical Physics (ICTP), P.O.Box 586, I-34014 Trieste (Italy)

    1997-03-01

    We have simulated by {ital ab initio} constant pressure molecular dynamics the solid-state polymerization of acetylene recently observed experimentally in the pressure range 3.5{endash}14 GPa. We have found a massive polymerization only at much higher pressure (25 GPa). However, we have also found that a triplet exciton self-trapped on a single, {ital cis}-bent molecule in crystalline acetylene is a very effective polymerization seed at lower pressure ({lt}9GPa), much closer to the experimental threshold. Therefore, we propose that the polymerization observed experimentally is possibly catalyzed by a similar seed. We predict that injection of triplet excitons would greatly enhance the polymerization rate. {copyright} {ital 1997} {ital The American Physical Society}

  16. Enthalpies of vaporization of some acetylene peroxy derivatives of carboranes-12

    International Nuclear Information System (INIS)

    Dibrivnyj, V.N.; Pistun, Z.E.; Van-Chin-Syan, Yu.Ya.; Yuvchenko, A.P.; Zvereva, T.D.

    1999-01-01

    Temperature dependences of saturated vapor pressure and vaporization enthalpies of five acetylene peroxy derivatives of carboranes-12 are determined by the Knudsen effusion method. Enthalpies and melting points of crystals, as well as temperatures of liquid compounds decomposition start are determined by the method of differential scanning calorimetry. Comparison of evaporation enthalpies determined in the study confirms the conclusions on non-additive character of intermolecular interaction in carboranes and their derivatives, which have been made previously [ru

  17. Coupled Hartree-Fock calculation of {sup 13} C shielding tensors in acetylene clusters

    Energy Technology Data Exchange (ETDEWEB)

    Craw, John Simon; Nascimento, Marco Antonio Chaer [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica

    1992-12-31

    The coupled Hartree Fock method has been used to calculate ab-initio carbon magnetic shielding tensors for small clusters of acetylene molecules. The chemical shift increases from the monomer to the dimer and trimer. This is mainly due increased diamagnetism, which is imperfectly cancelled by increased paramagnetism due to loss of axial symmetry. Anisotropic effects are shown to be small in both the dimer the and trimer. (author) 21 refs., 2 tabs.

  18. Dual fuel operation of used transformer oil with acetylene in a DI diesel engine

    International Nuclear Information System (INIS)

    Behera, Pritinika; Murugan, S.; Nagarajan, G.

    2014-01-01

    Highlights: • Utilisation of Used transformer oil (UTO) as a fuel in a diesel engine. • UTO with acetylene in a diesel engine, on a dual fuel mode technique. • Analysis of combustion characteristics of the diesel engine. • Analysis of performance and emission characteristics of the diesel engine. - Abstract: Used transformer oil (UTO) is a waste oil obtained from power transformers and welding transformers. It possesses considerable heating value and properties similar to diesel fuel. A preliminary investigation on the utilization of the UTO in a single cylinder, four stroke small powered direct injection (DI) diesel engine revealed that at an optimum injection timing of 20°CA the engine exhibited lower nitric oxide (NO) and higher smoke emissions, compared to that of diesel operation. In order to improve the performance and reduce the smoke emission, a dual fuel operation was attempted in the present investigation. Acetylene was inducted as a primary fuel at four different flow rates viz 132 g/h, 198 g/h, 264 g/h and 330 g/h along with the air, to study the combustion, performance and emission behavior of a four-stroke, 4.4 kW diesel engine, while the UTO was injected as pilot fuel with the optimized injection timing. The experimental results were compared with diesel-acetylene dual fuel operation in the same engine. Acetylene aspiration reduced the ignition delay and maximum cylinder pressure by about 3°CA, and 25% respectively at full load in comparison with the sole UTO operation. Higher thermal efficiency and lower exhaust gas were also observed at full load. Smoke was reduced by about 13.7%, in comparison with the UTO operation at full load

  19. Tracing Acetylene Dissolved in Transformer Oil by Tunable Diode Laser Absorption Spectrum.

    Science.gov (United States)

    Ma, Guo-Ming; Zhao, Shu-Jing; Jiang, Jun; Song, Hong-Tu; Li, Cheng-Rong; Luo, Ying-Ting; Wu, Hao

    2017-11-02

    Dissolved gas analysis (DGA) is widely used in monitoring and diagnosing of power transformer, since the insulation material in the power transformer decomposes gases under abnormal operation condition. Among the gases, acetylene, as a symbol of low energy spark discharge and high energy electrical faults (arc discharge) of power transformer, is an important monitoring parameter. The current gas detection method used by the online DGA equipment suffers from problems such as cross sensitivity, electromagnetic compatibility and reliability. In this paper, an optical gas detection system based on TDLAS technology is proposed to detect acetylene dissolved in transformer oil. We selected a 1530.370 nm laser in the near infrared wavelength range to correspond to the absorption peak of acetylene, while using the wavelength modulation strategy and Herriott cell to improve the detection precision. Results show that the limit of detection reaches 0.49 ppm. The detection system responds quickly to changes of gas concentration and is easily to maintenance while has no electromagnetic interference, cross-sensitivity, or carrier gas. In addition, a complete detection process of the system takes only 8 minutes, implying a practical prospect of online monitoring technology.

  20. Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

    Science.gov (United States)

    Han, Huixian; Li, Anyang; Guo, Hua

    2014-12-01

    A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S0) electronic state has been constructed by fitting ˜37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm-1. The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm-1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction.

  1. Toward spectroscopically accurate global ab initio potential energy surface for the acetylene-vinylidene isomerization

    International Nuclear Information System (INIS)

    Han, Huixian; Li, Anyang; Guo, Hua

    2014-01-01

    A new full-dimensional global potential energy surface (PES) for the acetylene-vinylidene isomerization on the ground (S 0 ) electronic state has been constructed by fitting ∼37 000 high-level ab initio points using the permutation invariant polynomial-neural network method with a root mean square error of 9.54 cm −1 . The geometries and harmonic vibrational frequencies of acetylene, vinylidene, and all other stationary points (two distinct transition states and one secondary minimum in between) have been determined on this PES. Furthermore, acetylene vibrational energy levels have been calculated using the Lanczos algorithm with an exact (J = 0) Hamiltonian. The vibrational energies up to 12 700 cm −1 above the zero-point energy are in excellent agreement with the experimentally derived effective Hamiltonians, suggesting that the PES is approaching spectroscopic accuracy. In addition, analyses of the wavefunctions confirm the experimentally observed emergence of the local bending and counter-rotational modes in the highly excited bending vibrational states. The reproduction of the experimentally derived effective Hamiltonians for highly excited bending states signals the coming of age for the ab initio based PES, which can now be trusted for studying the isomerization reaction

  2. Promising SiC support for Pd catalyst in selective hydrogenation of acetylene to ethylene

    Science.gov (United States)

    Guo, Zhanglong; Liu, Yuefeng; Liu, Yan; Chu, Wei

    2018-06-01

    In this study, SiC supported Pd nanoparticles were found to be an efficient catalyst in acetylene selective hydrogenation reaction. The ethylene selectivity can be about 20% higher than that on Pd/TiO2 catalyst at the same acetylene conversion at 90%. Moreover, Pd/SiC catalyst showed a stable catalytic life at 65 °C with 80% ethylene selectivity. With the detailed characterization using temperature-programmed reduction (H2-TPR), powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2 adsorption/desorption analysis, CO-chemisorption and thermo-gravimetric analysis (TGA), it was found that SiC owns a lower surface area (22.9 m2/g) and a broad distribution of meso-/macro-porosity (from 5 to 65 nm), which enhanced the mass transfer during the chemical process at high reaction rate and decreased the residence time of ethylene on catalyst surface. Importantly, SiC support has the high thermal conductivity, which favored the rapid temperature homogenization through the catalyst bed and inhabited the over-hydrogenation of acetylene. The surface electronic density of Pd on Pd/SiC catalyst was higher than that on Pd/TiO2, which could promote desorption of ethylene from surface of the catalyst. TGA results confirmed a much less coke deposition on Pd/SiC catalyst.

  3. Pulsed-induced electromagnetically induced transparency in the acetylene-filled hollow-core fibers

    Science.gov (United States)

    Rodríguez, Nayeli Casillas; Stepanov, Serguei; Miramontes, Manuel Ocegueda; Hernández, Eliseo Hernández

    2017-06-01

    Experimental results on pulsed excitation of electromagnetically induced transparency (EIT) in the acetylene-filled hollow-core photonic crystal fiber (HC-PCF) at pressures 0.1-0.4 Torr are reported. The EIT was observed both in Λ and V interaction configurations with the continuous probe wave tuned to R9 (1520.08 nm) acetylene absorption line and with the control pulses tuned to P11 (1531.58 nm) and P9 (1530.37 nm) lines, respectively. The utilized control pulses were of up to 40 ns duration with EIT was up to 40 and 15% for the co- and counter-propagation of the probe and control waves, respectively, and importance of the waves polarization matching was demonstrated. For a qualitative explanation of reduction in the counter-propagation EIT efficiency a simple model of the accelerated mismatch of the two-frequency EIT resonance with deviation of the molecule thermal velocity from the resonance value was utilized. It was shown experimentally that the EIT efficiencies in both configurations do not depend on the longitudinal velocity of the molecules. The characteristic relaxation time of the of the EIT response was found to be about 9 ns, i.e., is close to the relaxation times T 1,2 of the acetylene molecules under the utilized experimental conditions.

  4. Positron collisions with acetylene calculated using the R-matrix with pseudo-states method

    Science.gov (United States)

    Zhang, Rui; Galiatsatos, Pavlos G.; Tennyson, Jonathan

    2011-10-01

    Eigenphase sums, total cross sections and differential cross sections are calculated for low-energy collisions of positrons with C2H2. The calculations demonstrate that the use of appropriate pseudo-state expansions very significantly improves the representation of this process giving both realistic eigenphases and cross sections. Differential cross sections are strongly forward peaked in agreement with the measurements. These calculations are computationally very demanding; even with improved procedures for matrix diagonalization, fully converged calculations are too expensive with current computer resources. Nonetheless, the calculations show clear evidence for the formation of a virtual state but no indication that acetylene actually binds a positron at its equilibrium geometry.

  5. Frequency metrology of the acetylene lines near 789 nm from lamb-dip measurements

    Science.gov (United States)

    Tao, Lei-Gang; Hua, Tian-Peng; Sun, Yu R.; Wang, Jin; Liu, An-Wen; Hu, Shui-Ming

    2018-05-01

    Lamb-dips of the ro-vibrational lines of 12C2H2 near 789 nm were recorded using cavity ring-down saturation spectroscopy. Calibrated by an optical frequency comb, frequencies of 45 acetylene lines were determined with an accuracy of 1.1 ×10-7 cm-1 (δν / ν = 8 ×10-12), which is over two orders of magnitude more accurate than previous Doppler-limited studies. An averaged shift of about 0.01 cm-1 were found by comparing the upper energies obtained in this work to those recently presented by Chubb et al. from a MARVEL analysis.

  6. Creation and behavior of radicals and ions in the Acetylene/Argon microwave ECR discharge

    Czech Academy of Sciences Publication Activity Database

    Pokorný, Petr; Musil, Jindřich; Novotný, Michal; Lančok, Ján; Fitl, Přemysl; Vlček, Jan

    2017-01-01

    Roč. 14, č. 12 (2017), s. 1-9, č. článku 1700062. ISSN 1612-8850 R&D Projects: GA ČR GA17-13427S; GA MŠk LO1409; GA MŠk LM2015088 Institutional support: RVO:68378271 Keywords : acetylene * ECR discharge * ions * mass spectrometry * radicals Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 2.846, year: 2016

  7. Synthesis of Novel E-2-Chlorovinyltellurium Compounds Based on the Stereospecific Anti-addition of Tellurium Tetrachloride to Acetylene

    Directory of Open Access Journals (Sweden)

    Svetlana V. Amosova

    2012-05-01

    Full Text Available The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyltellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl3 under a pressure of acetylene of 10–15 atm, whereas the former product was formed in up to 72% yield in CCl4 under a pressure of acetylene of 1–3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl telluride, E,E-bis(2-chlorovinyl ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl-tellurium dibromide is described.

  8. Acetylene and carbon monoxide oxidation over a Pt/Rh/CeO2/γ-Al2O3 automotive exhaust gas catalyst: kinetic modelling of transient experiments

    NARCIS (Netherlands)

    Harmsen, J.M.A.; Hoebink, J.H.B.J.; Schouten, J.C.

    2001-01-01

    The transient kinetics of acetylene (C2H2) conversion by oxygen over a commercial Pt/Rh/CeO2/¿-Al2O3 three-way catalyst have been modelled. Experiments to validate the model were carried out in a fixed-bed reactor with two separate inlets, enabling alternate feeding of acetylene and oxygen.

  9. 2-methyl-3-butyn-2-ol as an acetylene precursor in the Mannich reaction. A new synthesis of suicide inactivators of monoamine oxidase

    International Nuclear Information System (INIS)

    Fowler, J.S.

    1977-01-01

    A two-step reaction process is reported for the synthesis of 11 C, 13 C, or 14 C-labelled propargylamines in moderate yields. The propargylamines were prepared by a modified Mannich scheme without the use of acetylene. The reaction scheme involved the use of 2-methyl-3-butyn-2-ol followed by KOH-catalyzed elimination of acetone from the acetylenic carbinols

  10. High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8 μm

    International Nuclear Information System (INIS)

    Sajid, M.B.; Javed, T.; Farooq, A.

    2015-01-01

    The mid-infrared wavelength region near 8 μm contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the ν 4 band of methane and the ν 4 +ν 5 band of acetylene is reported for interference-free, time-resolved measurements under combustion-relevant conditions. A detailed line-selection procedure was used to identify optimum transitions. Methane and acetylene were measured at the line centers of Q12 (1303.5 cm −1 ) and P23 (1275.5 cm −1 ) transitions, respectively. High-temperature absorption cross sections of methane and acetylene were measured at peaks (on-line) and valleys (off-line) of the selected absorption transitions. The differential absorption strategy was employed to eliminate interference absorption from large hydrocarbons. Experiments were performed behind reflected shock waves over a temperature range of 1200–2200 K, between pressures of 1–4 atm. The diagnostics were then applied to measure the respective species time-history profiles during the shock-heated pyrolysis of n-pentane. - Highlights: • Methane measured at the peak of Q(12) transition in the ν 4 band. • Acetylene measured at the peak of P(23) transition in the ν 4 +ν 5 band. • Differential absorption strategy employed to eliminate broadband interference absorption. • Absorption cross-sections measured over 1200–2200 K and 1–4 atm. • Methane and acetylene time-histories measured during the pyrolysis of n-pentane

  11. Ab initio dynamics and photoionization mass spectrometry reveal ion-molecule pathways from ionized acetylene clusters to benzene cation.

    Science.gov (United States)

    Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P; Fang, Yigang; Kostko, Oleg; Ahmed, Musahid; Head-Gordon, Martin

    2017-05-23

    The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion-molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C 2 H 2 ) n + , just like ionized acetylene clusters. The fragmentation products result from reactive ion-molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C 4 H 4 + and C 6 H 6 + structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C 2 H 2 ) n + isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C 6 H 6 + isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM.

  12. Ab initio dynamics and photoionization mass spectrometry reveal ion–molecule pathways from ionized acetylene clusters to benzene cation

    Science.gov (United States)

    Stein, Tamar; Bandyopadhyay, Biswajit; Troy, Tyler P.; Fang, Yigang; Kostko, Oleg

    2017-01-01

    The growth mechanism of hydrocarbons in ionizing environments, such as the interstellar medium (ISM), and some combustion conditions remains incompletely understood. Ab initio molecular dynamics (AIMD) simulations and molecular beam vacuum-UV (VUV) photoionization mass spectrometry experiments were performed to understand the ion–molecule growth mechanism of small acetylene clusters (up to hexamers). A dramatic dependence of product distribution on the ionization conditions is demonstrated experimentally and understood from simulations. The products change from reactive fragmentation products in a higher temperature, higher density gas regime toward a very cold collision-free cluster regime that is dominated by products whose empirical formula is (C2H2)n+, just like ionized acetylene clusters. The fragmentation products result from reactive ion–molecule collisions in a comparatively higher pressure and temperature regime followed by unimolecular decomposition. The isolated ionized clusters display rich dynamics that contain bonded C4H4+ and C6H6+ structures solvated with one or more neutral acetylene molecules. Such species contain large amounts (>2 eV) of excess internal energy. The role of the solvent acetylene molecules is to affect the barrier crossing dynamics in the potential energy surface (PES) between (C2H2)n+ isomers and provide evaporative cooling to dissipate the excess internal energy and stabilize products including the aromatic ring of the benzene cation. Formation of the benzene cation is demonstrated in AIMD simulations of acetylene clusters with n > 3, as well as other metastable C6H6+ isomers. These results suggest a path for aromatic ring formation in cold acetylene-rich environments such as parts of the ISM. PMID:28484019

  13. Simultaneous measurements of acetylene and soot during the pyrolysis of ethylene and benzene in a shock tube

    KAUST Repository

    KC, Utsav

    2016-10-12

    Acetylene is one of the most important precursors of soot and contributes to soot growth by the hydrogen-abstraction acetylene-addition (HACA) mechanism. In this work, we undertake time-resolved simultaneous measurements of acetylene and soot behind reflected shock waves at temperatures of 1600-2200. K and pressures of 3-5. bar. Acetylene mole fraction time-histories are measured from the absorption of a quantum-cascade laser operating around 13.6. μm. The soot volume fraction, particle size and number densities are calculated from the extinction and scattering of a cw Nd:Yag laser at 532. nm. Acetylene and soot are generated from the pyrolysis of 1% benzene in argon, 2.35% ethylene in argon, and binary mixtures of ethylene with propane/methane in argon. We note that acetylene time-histories exhibit a two-stage growth during the pyrolysis of benzene, which can be correlated to the initial rapid increase of soot volume fraction and a later plateauing. In comparison to ethylene pyrolysis, the pyrolysis of benzene results in larger values of the soot volume fraction, particle diameter and number density. We compare the measured data against the values simulated using the method-of-moments routine in Chemkin-Pro and a detailed PAH mechanism based on KM2 [1] and AramcoMech 1.3 [2]. Large discrepancies are observed between the measured and predicted values of the soot parameters. The data obtained from our experiments may assist future validation and development of soot mechanisms.

  14. Theoretical insights into acetylene adsorption on nanoporous gold surfaces: Role of residual silver

    Science.gov (United States)

    Luo, Yafei; Chen, Zhongzhu; Xu, Zhigang; Yang, Donglin; Zhang, Jin; Tang, Dianyong

    2018-03-01

    Unveiling the acetylene adsorption is crucial for designing novel and highly active catalyst for the semihydrogenation of alkyne. In order to achieve this goal, we have studied C2H2 adsorption on the various nanoporous gold models in detail, including the Au(100), Au(111) and Au(321) slab models. The calculated results indicate that the C atoms of C2H2 experience rehybridization from sp toward sp2/sp3 when the adsorption occurs on bridge and hollow sites, which can be illustrated via the projected density of state (PDOS) and crystal orbital Hamilton population (COHP). Meanwhile, the formation of σ(Ausbnd C) bond is beneficial for facilitating acetylene adsorption and the kink Au atom plays an important role for the C2H2 adsorption. In addition, for C2H2 adsorption on the Ag doped nanoporous gold, the configurations strongly depend on the position of superficial unsubstituted Au atoms. Further, the inversely relationship has been found between the adsorption energies and number of the Ag substituents, demonstrating that the superficial Ag substituents are harmful for C2H2 adsorption and activation.

  15. Acetylene Flow Rate as a Crucial Parameter of Vacuum Carburizing Process of Modern Tool Steels

    Directory of Open Access Journals (Sweden)

    Rokicki P.

    2016-12-01

    Full Text Available Carburizing is one of the most popular and wide used thermo-chemical treatment methods of surface modification of tool steels. It is a process based on carbon diffusive enrichment of the surface material and is applied for elements that are supposed to present higher hardness and wear resistance sustaining core ductility. Typical elements submitted to carburizing process are gears, shafts, pins and bearing elements. In the last years, more and more popular, especially in highly advanced treatment procedures used in the aerospace industry is vacuum carburizing. It is a process based on chemical treatment of the surface in lower pressure, providing much higher uniformity of carburized layer, lower process cost and much lesser negative impact on environment to compare with conventional carburizing methods, as for example gas carburizing in Endo atmosphere. Unfortunately, aerospace industry requires much more detailed description of the phenomena linked to this process method and the literature background shows lack of tests that could confirm fulfilment of all needed requirements and to understand the process itself in much deeper meaning. In the presented paper, authors focused their research on acetylene flow impact on carburized layer characteristic. This is one of the most crucial parameters concerning homogeneity and uniformity of carburized layer properties. That is why, specific process methodology have been planned based on different acetylene flow values, and the surface layer of the steel gears have been investigated in meaning to impact on any possible change in potential properties of the final product.

  16. Denitrification rate determined by nitrate disapperance is higher than determined by nitrous oxide production with acetylene blockage

    DEFF Research Database (Denmark)

    Yu, Kewei; Struwe, Sten; Kjøller, Annelise

    2008-01-01

    A mixed beech and spruce forest soil was incubated under potential denitrification assay (PDA) condition with 10% acetylene (C2H2) in the headspace of soil slurry bottles. Nitrous oxide (N2O) concentration in the headspace, as well as nitrate, nitrite and ammonium concentrations in the soil slurr...

  17. Acetylene and oxygen as inhibitors of nitrous oxide production in Nitrosomonas europaea and Nitrosospira briensis: a cautionary tale

    NARCIS (Netherlands)

    Wrage, N.; Velthof, G.L.; Oenema, O.; Laanbroek, H.J.

    2004-01-01

    Autotrophic ammonia-oxidizing bacteria produce nitrous oxide (N2O) as a by-product of nitrification or as an intermediate of nitrifier denitrification. In soil incubations, acetylene (C2H2) and large partial pressures of oxygen (O2) are used to distinguish between these sources. C2H2 inhibits

  18. High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8μm

    KAUST Repository

    Sajid, M.B.; Javed, Tamour; Farooq, Aamir

    2015-01-01

    The mid-infrared wavelength region near 8 mu m contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the v(4) band of methane and the v(4

  19. Simultaneous measurements of acetylene and soot during the pyrolysis of ethylene and benzene in a shock tube

    KAUST Repository

    KC, Utsav; Beshir, Mohamed; Farooq, Aamir

    2016-01-01

    reflected shock waves at temperatures of 1600-2200. K and pressures of 3-5. bar. Acetylene mole fraction time-histories are measured from the absorption of a quantum-cascade laser operating around 13.6. μm. The soot volume fraction, particle size and number

  20. Structure, Stabilities, Thermodynamic Properties, and IR Spectra of Acetylene Clusters (C2H2)n=2-5.

    Science.gov (United States)

    Karthikeyan, S; Lee, Han Myoung; Kim, Kwang S

    2010-10-12

    There are no clear conclusions over the structures of the acetylene clusters. In this regard, we have carried out high-level calculations for acetylene clusters (C2H2)2-5 using dispersion-corrected density functional theory (DFT-D), Møller-Plesset second-order perturbation theory (MP2); and coupled-cluster theory with single, double, and perturbative triple excitations [CCSD(T)] at the complete basis set limit. The lowest energy structure of the acetylene dimer has a T-shaped structure of C2v symmetry, but it is nearly isoenergetic to the displaced stacked structure of C2h symmetry. We find that the structure shows the quantum statistical distribution for configurations between the T-shaped and displaced stacked structures for which the average angle (|θ̃|) between two acetylene molecules would be 53-78°, close to the T-shaped structure. The trimer has a triangular structure of C3h symmetry. The tetramer has two lowest energy isomers of S4 and C2h symmetry in zero-point energy (ZPE)-uncorrected energy (ΔEe), but one lowest energy isomer of C2v symmetry in ZPE-corrected energy (ΔE0). For the pentamer, the global minimum structure is C1 symmetry with eight sets of T-type π-H interactions and a set of π-π interactions. Our high-level ab initio calculations are consistent with available experimental data.

  1. High-temperature measurements of methane and acetylene using quantum cascade laser absorption near 8μm

    KAUST Repository

    Sajid, M.B.

    2015-04-01

    The mid-infrared wavelength region near 8 mu m contains absorption bands of several molecules such as water vapor, hydrogen peroxide, nitrous oxide, methane and acetylene. A new laser absorption sensor based on the v(4) band of methane and the v(4)+v(5) band of acetylene is reported for interference-free, time-resolved measurements under combustion-relevant conditions. A detailed line-selection procedure was used to identify optimum transitions. Methane and acetylene were measured at the line centers of Q12 (1303.5 cm(-1)) and P23 (1275.5 cm(-1)) transitions, respectively. High-temperature absorption cross sections of methane and acetylene were measured at peaks (on-line) and valleys (off-line) of the selected absorption transitions. The differential absorption strategy was employed to eliminate interference absorption from large hydrocarbons. Experiments were performed behind reflected shock waves over a temperature range of 1200-2200 K, between pressures of 1-4 atm. The diagnostics were then applied to measure the respective species time-history profiles during the shock-heated pyrolysis of n-pentane. (C) 2015 Elsevier Ltd. All rights reserved.

  2. Plasma Polymerization of Acetylene onto silica: and Approach to control the distribution of silica in single elastomers and immiscible blends

    NARCIS (Netherlands)

    Tiwari, M.; Noordermeer, Jacobus W.M.; Ooij, W.J.; Dierkes, Wilma K.

    2008-01-01

    Surface modification of silica by acetylene plasma polymerization is applied in order to improve the dispersion in and compatibility with single rubbers and their blends. Silica, used as a reinforcing filler for elastomers, is coated with a polyacetylene (PA) film under vacuum conditions. Water

  3. Carbon material formation on SBA-15 and Ni-SBA-15 and residue constituents during acetylene decomposition

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Hung-Lung, E-mail: hlchiang@mail.cmu.edu.tw [Department of Risk Management, China Medical University, Taichung 40402, Taiwan (China); Wu, Trong-Neng [Department of Public Health, China Medical University, Taichung 40402, Taiwan (China); Ho, Yung-Shou [Department of Applied Chemistry and Materials Science, Fooyin University, Kaohsiung 831, Taiwan (China); Zeng, Li-Xuan [Department of Risk Management, China Medical University, Taichung 40402, Taiwan (China)

    2014-07-15

    Highlights: • Acetylene was decomposed on SBA-15 and Ni-SBA-15 at 650–850 °C. • Carbon spheres and filaments were formed after acetylene decomposition. • PAHs were determined in tar and residues. • Exhaust constituents include CO{sub 2}, H{sub 2}, NO{sub x} and hydrocarbon species. - Abstract: Carbon materials including carbon spheres and nanotubes were formed from acetylene decomposition on hydrogen-reduced SBA-15 and Ni-SBA-15 at 650–850 °C. The physicochemical characteristics of SBA-15, Ni-SBA-15 and carbon materials were analyzed by field emission scanning electronic microscopy (FE-SEM), Raman spectrometry, and energy dispersive spectrometry (EDS). In addition, the contents of polyaromatic hydrocarbons (PAHs) in the tar and residue and volatile organic compounds (VOCs) in the exhaust were determined during acetylene decomposition on SBA-15 and Ni-SBA-15. Spherical carbon materials were observed on SBA-15 during acetylene decomposition at 750 and 850 °C. Carbon filaments and ball spheres were formed on Ni-SBA-15 at 650–850 °C. Raman spectroscopy revealed peaks at 1290 (D-band, disorder mode, amorphous carbon) and 1590 (G-band, graphite sp{sup 2} structure) cm{sup −1}. Naphthalene (2 rings), pyrene (4 rings), phenanthrene (3 rings), and fluoranthene (4 rings) were major PAHs in tar and residues. Exhaust constituents of hydrocarbon (as propane), H{sub 2}, and C{sub 2}H{sub 2} were 3.9–2.6/2.7–1.5, 1.4–2.8/2.6–4.3, 4.2–2.4/3.2–1.7% when acetylene was decomposed on SBA-15/Ni-SBA-15, respectively, corresponding to temperatures ranging from 650 to 850 °C. The concentrations of 52 VOCs ranged from 9359 to 5658 and 2488 to 1104 ppm for SBA-15 and Ni-SBA-15 respectively, at acetylene decomposition temperatures from 650 to 850 °C, and the aromatics contributed more than 87% fraction of VOC concentrations.

  4. An Empirical Spectroscopic Database for Acetylene in the Regions of 5850-9415 CM^{-1}

    Science.gov (United States)

    Campargue, Alain; Lyulin, Oleg

    2017-06-01

    Six studies have been recently devoted to a systematic analysis of the high-resolution near infrared absorption spectrum of acetylene recorded by Cavity Ring Down spectroscopy (CRDS) in Grenoble and by Fourier-transform spectroscopy (FTS) in Brussels and Hefei. On the basis of these works, in the present contribution, we construct an empirical database for acetylene in the 5850 - 9415 \\wn region excluding the 6341-7000 \\wn interval corresponding to the very strong νb{1}+ νb{3} manifold. The database gathers and extends information included in our CRDS and FTS studies. In particular, the intensities of about 1700 lines measured by CRDS in the 7244-7920 \\wn are reported for the first time together with those of several bands of ^{12}C^{13}CH_{2} present in natural isotopic abundance in the acetylene sample. The Herman-Wallis coefficients of most of the bands are derived from a fit of the measured intensity values. A recommended line list is provided with positions calculated using empirical spectroscopic parameters of the lower and upper energy vibrational levels and intensities calculated using the derived Herman-Wallis coefficients. This approach allows completing the experimental list by adding missing lines and improving poorly determined positions and intensities. As a result the constructed line list includes a total of 10973 lines belonging to 146 bands of ^{12}C_{2}H_{2} and 29 bands of ^{12}C^{13}CH_{2}. For comparison the HITRAN2012 database in the same region includes 869 lines of 14 bands, all belonging to ^{12}C_{2}H_{2}. Our weakest lines have an intensity on the order of 10^{-29} cm/molecule,about three orders of magnitude smaller than the HITRAN intensity cut off. Line profile parameters are added to the line list which is provided in HITRAN format. The comparison to the HITRAN2012 line list or to results obtained using the global effective operator approach is discussed in terms of completeness and accuracy.

  5. Infrared Spectra and Optical Constants of Astronomical Ices: I. Amorphous and Crystalline Acetylene

    Science.gov (United States)

    Hudson, R. L.; Ferrante, R. F.; Moore, M. H.

    2013-01-01

    Here we report recent measurements on acetylene (C2H2) ices at temperatures applicable to the outer Solar System and the interstellar medium. New near- and mid-infrared data, including optical constants (n, k), absorption coefficients (alpha), and absolute band strengths (A), are presented for both amorphous and crystalline phases of C2H2 that exist below 70 K. Comparisons are made to earlier work. Electronic versions of the data are made available, as is a computer routine to use our reported n and k values to simulate the observed IR spectra. Suggestions are given for the use of the data and a comparison to a spectrum of Makemake is made.

  6. Indirect determination of uranium by atomic-absorption spectrophotometry using an air-acetylene flame

    International Nuclear Information System (INIS)

    Alder, J.F.; Das, B.C.

    1977-01-01

    An indirect method has been developed for the determination of uranium by atomic-absorption spectrophotometry using an air-acetylene flame. Use is made of the reduction of copper(II) by uranium(IV) followed by complex formation of the copper(I) ions so produced with neocuproine (2,9-dimethyl-1,10-phenanthroline) and finally the determination of copper in this complex by atomic-absorption spectrophotometry. The results show that the method can be recommended, provided that care is taken to ensure the complete reduction of uranium(VI) to uranium(IV). The sensitivity of the method is 4.9 μg of uranium and the upper limit 500 μg without dilution. (author)

  7. Positron collisions with acetylene calculated using the R-matrix with pseudo-states method

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Rui; Galiatsatos, Pavlos G; Tennyson, Jonathan, E-mail: j.tennyson@ucl.ac.uk [Department of Physics and Astronomy, University College London, Gower St., London WC1E 6BT (United Kingdom)

    2011-10-14

    Eigenphase sums, total cross sections and differential cross sections are calculated for low-energy collisions of positrons with C{sub 2}H{sub 2}. The calculations demonstrate that the use of appropriate pseudo-state expansions very significantly improves the representation of this process giving both realistic eigenphases and cross sections. Differential cross sections are strongly forward peaked in agreement with the measurements. These calculations are computationally very demanding; even with improved procedures for matrix diagonalization, fully converged calculations are too expensive with current computer resources. Nonetheless, the calculations show clear evidence for the formation of a virtual state but no indication that acetylene actually binds a positron at its equilibrium geometry.

  8. Effect of Iminodiacetic Acid-Modified Nieuwland Catalyst on the Acetylene Dimerization Reaction

    Directory of Open Access Journals (Sweden)

    Yanhe You

    2017-12-01

    Full Text Available The iminodiacetic acid-modified Nieuwland catalyst not only improves the conversion of acetylene but also increases the selectivity of monovinylacetylene (MVA. A catalyst system containing 4.5% iminodiacetic acid exhibited excellent performance, and the yield of MVA was maintained at 32% after 24 h, producing an increase in the yield by 12% relative to the Nieuwland catalyst system. Based on a variety of characterization methods analysis of the crystal precipitated from the catalyst solution, it can be inferred that the outstanding performance and lifetime of the catalyst system was due to the presence of iminodiacetic acid, which increases the electron density of Cu+ and adjusts the acidity of the catalytic solution.

  9. Pressure-Induced Polymerization of Acetylene: Structure-Directed Stereoselectivity and a Possible Route to Graphane.

    Science.gov (United States)

    Sun, Jiangman; Dong, Xiao; Wang, Yajie; Li, Kuo; Zheng, Haiyan; Wang, Lijuan; Cody, George D; Tulk, Christopher A; Molaison, Jamie J; Lin, Xiaohuan; Meng, Yufei; Jin, Changqing; Mao, Ho-Kwang

    2017-06-01

    Geometric isomerism in polyacetylene is a basic concept in chemistry textbooks. Polymerization to cis-isomer is kinetically preferred at low temperature, not only in the classic catalytic reaction in solution but also, unexpectedly, in the crystalline phase when it is driven by external pressure without a catalyst. Until now, no perfect reaction route has been proposed for this pressure-induced polymerization. Using in situ neutron diffraction and meta-dynamic simulation, we discovered that under high pressure, acetylene molecules react along a specific crystallographic direction that is perpendicular to those previously proposed. Following this route produces a pure cis-isomer and more surprisingly, predicts that graphane is the final product. Experimentally, polycyclic polymers with a layered structure were identified in the recovered product by solid-state nuclear magnetic resonance and neutron pair distribution functions, which indicates the possibility of synthesizing graphane under high pressure. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. A New Acetylenic Compound and Other Bioactive Metabolites from a Shark Gill-derived Penicillium Strain

    Directory of Open Access Journals (Sweden)

    Yi Zhang

    2017-01-01

    Full Text Available Nine chiral compounds (1−9 were isolated from the static fermentation culture of a shark gill-derived fungus Penicillium polonicum AP2T1. These compounds include a new acetylenic aromatic ether (1 , (--WA , four alkaloids ( a urantiomide C ( 2 , fructigenine A (3, cyclopenin (4 and cyclopenol (5 and four oxygenated compounds ((R-penipratynolene (6, (3S,4S-3,4-dihydro-3,4,8-trihydroxyl-naphthalenone (7, verrucosidin (8 and norverrucosidin (9. Their structures were elucidated by MS, NMR , optical rotation and circular dichroism (CD . In antimicrobial tests , compounds 1–4, 6 and 8–9 showed weak antibacterial activity against Staphylococcus aureus, Bacillus subtilis, and/or Escherichia coli.Compounds 3, 8 and 9 also exhibited moderate toxicity against Artemia salina larva , and showed cytotoxicity against human colon cancer cell line HCT116.

  11. Substitution of Acetylene Black by Using Modified Flake Graphite Applied in Activated Carbon Supercapacitors

    Directory of Open Access Journals (Sweden)

    Zhao Peng

    2018-01-01

    Full Text Available Flake graphite was mechanically modified at different times in N-methyl pyrrolidone under normal pressure. The results of the scanning electron microscopy, X-ray diffraction, and transmission electron microscopy suggested that the structure of the flake graphite was modified. The crystallinity of the flake graphite, and many defects were introduced into the material. The evaluation of capacitor performance by cyclic voltammetry, galvanostatic charge/discharge tests, and electrochemical impedance spectroscopy was also performed. Results showed that the electrochemical performance of flake graphite was strongly enhanced, particularly when it was exfoliated for 6 h. Moreover, the electrochemical capacitive properties of activated carbon were obviously enhanced through the substitution of acetylene black by flake graphite modified for 6 h.

  12. ACTIVATION OF ACETYLENE BY COORDINATION TO BIS-TRIPHENYLPHOSPHINE COMPLEX OF Pt(0: DFT STUDY

    Directory of Open Access Journals (Sweden)

    N. N. Gorinchoy

    2009-06-01

    Full Text Available The present work is devoted to the theoretical study of the activation of the acetylene molecule coordinated in the [Pt(PPh32C2H2] complex. By means of DFT calculations it is shown that the geometrical and electronic characteristics of the C2H2 are essentially changed due to its coordination. The subsequent detailed analysis of the molecular orbitals (MO of the active valence zone of this complex allows one to make important conclusion that this activation is being realized mainly due to the orbital back donation of 5d-electronic density from one of the occupied MOs of the complex [Pt(PPh32] to the unoccupied antibonding π*-MO of C2H2.

  13. Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

    Energy Technology Data Exchange (ETDEWEB)

    Országh, Juraj; Danko, Marián; Čechvala, Peter; Matejčík, Štefan, E-mail: matejcik@fmph.uniba.sk [Department of Experimental Physics, Faculty of Mathematics, Physics and Informatics, Comenius University in Bratislava, Mlynská dolina F-2, 842 48 Bratislava (Slovakia)

    2017-05-20

    The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholds of the particular dissociative channels.

  14. Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

    Science.gov (United States)

    Cheng, Peifu; Hu, Yun Hang

    2016-07-01

    Acetylene (C2H2) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C2H2 adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C2H2 adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C2H2 adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C2H2 adsorption on those MOFs.

  15. Computational simulations of hydrogen circular migration in protonated acetylene induced by circularly polarized light

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Xuetao; Li, Wen; Schlegel, H. Bernhard, E-mail: hbs@chem.wayne.edu [Department of Chemistry, Wayne State University, Detroit, Michigan 48202 (United States)

    2016-08-28

    The hydrogens in protonated acetylene are very mobile and can easily migrate around the C{sub 2} core by moving between classical and non-classical structures of the cation. The lowest energy structure is the T-shaped, non-classical cation with a hydrogen bridging the two carbons. Conversion to the classical H{sub 2}CCH{sup +} ion requires only 4 kcal/mol. The effect of circularly polarized light on the migration of hydrogens in oriented C{sub 2}H{sub 3}{sup +} has been simulated by Born-Oppenheimer molecular dynamics. Classical trajectory calculations were carried out with the M062X/6-311+G(3df,2pd) level of theory using linearly and circularly polarized 32 cycle 7 μm cosine squared pulses with peak intensity of 5.6 × 10{sup 13} W/cm{sup 2} and 3.15 × 10{sup 13} W/cm{sup 2}, respectively. These linearly and circularly polarized pulses transfer similar amounts of energy and total angular momentum to C{sub 2}H{sub 3}{sup +}. The average angular momentum vectors of the three hydrogens show opposite directions of rotation for right and left circularly polarized light, but no directional preference for linearly polarized light. This difference results in an appreciable amount of angular displacement of the three hydrogens relative to the C{sub 2} core for circularly polarized light, but only an insignificant amount for linearly polarized light. Over the course of the simulation with circularly polarized light, this corresponds to a propeller-like motion of the three hydrogens around the C{sub 2} core of protonated acetylene.

  16. A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

    International Nuclear Information System (INIS)

    Ma, Ling-Ling; Lv, Cun-Qin; Wang, Gui-Chang

    2017-01-01

    Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H_2 molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H_2. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of C−H/C−C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H_2 dissociation and

  17. A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

    Science.gov (United States)

    Ma, Ling-Ling; Lv, Cun-Qin; Wang, Gui-Chang

    2017-07-01

    Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H2 molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H2. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of Csbnd H/Csbnd C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H2 dissociation and

  18. A DFT study and micro-kinetic analysis of acetylene selective hydrogenation on Pd-doped Cu(111) surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Ling-Ling [Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071 (China); Lv, Cun-Qin, E-mail: lcq173@126.com [College of Chemistry and Environmental Engineering, Shanxi Datong University, Datong 037009, Shanxi Province (China); Wang, Gui-Chang, E-mail: wangguichang@nankai.edu.cn [Department of Chemistry, Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) and Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin 300071 (China)

    2017-07-15

    Semi-hydrogenation of acetylene in a hydrogen-rich stream is an industrially important process. Inspired by the recent experiments that Cu(111) surface doped by a small number of Pd atoms can exhibit excellent catalytic performance toward the dissociation of H{sub 2} molecule as well as the high selective hydrogenation of acetylene as compared with pure Cu and Pd metal alone at low-temperature, here we performed systematic first-principles calculations to investigate the corresponding reaction mechanism related to the acetylene hydrogenation processes on single atom alloys (SAAs) and monolayer Pd/Cu(111) (i.e.,1.00 ML Pd/Cu(111)) model catalysts in detail, and to explore the possible factors controlling the high selectivity on SAAs. Our results clearly demonstrate that the SAA catalyst has higher selectivity for the ethylene formation than that of 1.00 ML Pd/Cu(111), and lower activity for the acetylene conversion compared with that of 1.00 ML Pd/Cu(111). The relatively high selectivity on SAA is mainly due to the facile desorption of ethylene and moderate activity in the dissociation of molecular H{sub 2}. The main factor which lowers the selectivity towards the ethylene formation on 1.00 ML Pd/Cu(111) is that this system has a higher capacity to promote the breaking of C−H/C−C bonds, which leads to the formation of carbonaceous deposits and polymers such as benzene, and thus reduces the selectivity for the ethylene formation. Meanwhile, it was found that the desorption energy of ethylene on these two surfaces was smaller than the energy barrier of further hydrogenation, which results in the absence of ethane on these two systems. Micro-kinetic model analysis provides a further valuable insight into the evidence for the key factors controlling the catalytic activity and selectivity towards the selective hydrogenation of acetylene. Our findings may help people to design a highly selective hydrogenation catalyst by controlling the balance between the H{sub 2

  19. Shock tube/laser absorption measurements of methane, acetylene and ethylene during the pyrolysis of n-pentane and iso-pentane

    KAUST Repository

    Sajid, Muhammad Bilal; Javed, Tamour; Farooq, Aamir

    2015-01-01

    differ in their predictions of the oxidative and pyrolysis behavior of pentane isomers. This work provides new species time-history data to validate and improve pentane chemistry models. Methane, acetylene and ethylene are measured during the high

  20. 乙炔提浓装置高级炔管线堵塞原因浅析%Analysis on causes of higher acetylene pipe blocking of acetylene concentration system

    Institute of Scientific and Technical Information of China (English)

    谢全兵

    2011-01-01

    Causes of higher alkyne pipe blocking of acetylene concentration system in the natural gas-based acetylene production plant were found out by analyzing higher alkyne gas component concentration variation. Corresponding measures were proposed to prevent higher alkyne polymerization in the pipe and thus prolong the equipment operation cycle.%通过对高级炔气体组分含量变化进行分析,找出天然气制乙炔装置乙炔浓缩系统高级炔管线堵塞的原因,并提出了防止高级炔气体在管线内聚合、延长装置运行周期的措施.

  1. Development of a spectrofluorimetry-based device for determining the acetylene content in the oils of power transformers.

    Science.gov (United States)

    Quintella, Cristina M; Meira, Marilena; Silva, Weidson Leal; Filho, Rogério G D; Araújo, André L C; Júnior, Elias T S; Sales, Lindolfo J O

    2013-12-15

    Power transformers are essential for a functioning electrical system and therefore require special attention by maintenance programs because a fault can harm both the company and society. The temperature inside a power transformer and the dissolved gases, which are primarily composed of acetylene, are the two main parameters monitored when detecting faults. This paper describes the development of a device for analyzing the acetylene content in insulating oil using spectrofluorimetry. Using this device introduces a new methodology for the maintaining and operating power transformers. The prototype is currently operating in a substation. The results presented by this system were satisfactory; when compared to chromatographic data, the errors did not exceed 15%. This prototype may be used to confirm the quality of an insulating oil sample to detect faults in power transformers. © 2013 Elsevier B.V. All rights reserved.

  2. A model for the ethylene and acetylene adsorption on the surface of Cu{sub n}(n = 10–15) nanoclusters: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Farmanzadeh, Davood, E-mail: d.farmanzad@umz.ac.ir; Abdollahi, Tahereh

    2016-11-01

    Highlights: • The most stable structures of Cu{sub n} (n = 10–15) were structures with C{sub S} symmetry. • It is expected that even clusters are better electron donors than the odd clusters. • Acetylene and ethylene adsorb molecularly on the Cu nanoclusters surface. • Acetylene never orient toward di-σ mode for Cu−Cu bond in odd copper nanoclusters. • For di- σ-Cu{sub n}C{sub 2}H{sub 4}, no stable structure is identified. - Abstract: In this work, we report the results of density functional theory calculations of ethylene and acetylene adsorption on the most stable Cu{sub n} (n = 10–15) nanoclusters, in two π and di- σ adsorption modes. Both the hydrocarbons molecularly adsorbed on the surface. Our results show that the quality of interaction of ethylene and acetylene with odd copper nanoclusters (n = 11, 13, 15) is different from what is found on even copper nanoclusters (n = 10, 12, 14). One of the interesting features of this adsorption is that acetylene never orient toward di-σ mode for Cu−Cu bond in odd copper nanoclusters. Also, for di- σ-Cu{sub n}C{sub 2}H{sub 4}, no stable structure is identified. The highest interaction and deformation energies are seen for the adsorption of acetylene and ethylene on Cu{sub 11} in π-mode.

  3. Excited-state dynamics of acetylene excited to individual rotational level of the V04K01 subband

    Science.gov (United States)

    Makarov, Vladimir I.; Kochubei, Sergei A.; Khmelinskii, Igor V.

    2006-01-01

    Dynamics of the IR emission induced by excitation of the acetylene molecule using the (32Ka0,1,2,ÃAu1←41la1,X˜Σg+1) transition was investigated. The observed IR emission was assigned to transitions between the ground-state vibrational levels. Acetylene fluorescence quenching induced by external electric and magnetic fields acting upon the system prepared using the (34Ka1,ÃAu1←00la0,X˜Σg+1) excitation was also studied. External electric field creates an additional radiationless pathway to the ground-state levels, coupling levels of the ÃAu1 excited state to the quasiresonant levels of the X˜Σg+1 ground state. The level density of the ground state in the vicinity of the excited state is very high, thus the electric-field-induced transition is irreversible, with the rate constant described by the Fermi rule. Magnetic field alters the decay profile without changing the fluorescence quantum yield in collisionless conditions. IR emission from the CCH transient was detected, and was also affected by the external electric and magnetic fields. Acetylene predissociation was demonstrated to proceed by the direct S1→S0 mechanism. The results were explained using the previously developed theoretical approach, yielding values of the relevant model parameters.

  4. Is the tungsten(IV complex (NEt42[WO(mnt2] a functional analogue of acetylene hydratase?

    Directory of Open Access Journals (Sweden)

    Matthias Schreyer

    2017-11-01

    Full Text Available The tungsten(IV complex (Et4N2[W(O(mnt2] (1; mnt = maleonitriledithiolate was proposed (Sarkar et al., J. Am. Chem. Soc. 1997, 119, 4315 to be a functional analogue of the active center of the enzyme acetylene hydratase from Pelobacter acetylenicus, which hydrates acetylene (ethyne; 2 to acetaldehyde (ethanal; 3. In the absence of a satisfactory mechanistic proposal for the hydration reaction, we considered the possibility of a metal–vinylidene type activation mode, as it is well established for ruthenium-based alkyne hydration catalysts with anti-Markovnikov regioselectivity. To validate the hypothesis, the regioselectivity of tungsten-catalyzed alkyne hydration of a terminal, higher alkyne had to be determined. However, complex 1 was not a competent catalyst for the hydration of 1-octyne under the conditions tested. Furthermore, we could not observe the earlier reported hydration activity of complex 1 towards acetylene. A critical assessment of, and a possible explanation for the earlier reported results are offered. The title question is answered with "no".

  5. Effect of injection pressure on performance, emission, and combustion characteristics of diesel-acetylene-fuelled single cylinder stationary CI engine.

    Science.gov (United States)

    Srivastava, Anmesh Kumar; Soni, Shyam Lal; Sharma, Dilip; Jain, Narayan Lal

    2018-03-01

    In this paper, the effect of injection pressure on the performance, emission, and combustion characteristics of a diesel-acetylene fuelled single cylinder, four-stroke, direct injection (DI) diesel engine with a rated power of 3.5 kW at a rated speed of 1500 rpm was studied. Experiments were performed in dual-fuel mode at four different injection pressures of 180, 190, 200, and 210 bar with a flow rate of 120 LPH of acetylene and results were compared with that of baseline diesel operation. Experimental results showed that highest brake thermal efficiency of 27.57% was achieved at injection pressure of 200 bar for diesel-acetylene dual-fuel mode which was much higher than 23.32% obtained for baseline diesel. Carbon monoxide, hydrocarbon, and smoke emissions were also measured and found to be lower, while the NO x emissions were higher at 200 bar in dual fuel mode as compared to those in other injection pressures in dual fuel mode and also for baseline diesel mode. Peak cylinder pressure, net heat release rate, and rate of pressure rise were also calculated and were higher at 200 bar injection pressure in dual fuel mode.

  6. Chromophores from photolyzed ammonia reacting with acetylene: Application to Jupiters Great Red Spot

    Science.gov (United States)

    Carlson, Robert W.; Baines, Kevin H.; Anderson, M. S.; Filacchione, G.; Simon, A. A.

    2016-01-01

    The high altitude of Jupiter's Great Red Spot (GRS) may enhance the upward flux of gaseous ammonia (NH3 ) into the high troposphere, where NH3 molecules can be photodissociated and initiate a chain of chemical reactions with downwelling acetylene molecules (C2H2 ). These reactions, experimentally studied earlier by (Ferris and Ishikawa [1987] Nature 326, 777-778) and (Ferris and Ishikawa [1988] J. Amer. Chem. Soc. 110, 4306-4312), produce chromophores that absorb in the visible and ultraviolet regions. In this work we photolyzed mixtures of NH3 and C2H2 using ultraviolet radiation with a wavelength of 214 nm and measured the spectral transmission of the deposited films in the visible region (400-740 nm). From these transmission data we estimated the imaginary indices of refraction. Assuming that ammonia grains at the top of the GRS clouds are coated with this material, we performed layered sphere and radiative transfer calculations to predict GRS reflection spectra. Comparison of those results with observed and previously unreported Cassini visible spectra and with true-color images of the GRS show that the unknown GRS chromophore is spectrally consistent with the coupled NH3-C2H2 photochemical products produced in our laboratory experiments. Using high-resolution mass spectrometry and infrared spectroscopy we infer that the chromophore-containing residue is composed of aliphatic azine, azo, and diazo compounds.

  7. In situ acetylene reduction activity of Scytonema julianum in Vapor cave (Spain

    Directory of Open Access Journals (Sweden)

    Asencio Antonia Dolores

    2011-01-01

    Full Text Available Nitrogen fixation was measured in situ for the first time by acetylene reduction for a greyish mat composed of Scytonema julianum in cave- like environments. Mat-specific rates (129.9-215.7 nmol C2 H4 m-2 s-1 for daytime fixation and 65.1-120.6 nmol C2 H4 m-2 s-1 for nighttime fixation recorded in the Vapor cave differed considerably due to the energy reserves stored during photosynthesis being exhausted and used in the dark phase. The most influential environmental parameter for nitrogen fixation in the Vapor cave is temperature in the daytime and nighttime fixations. Nitrogen fixation by cyanobacteria may contribute considerably to the overall nitrogen cycle in harsh environments such as caves. Nitrogenase activity in Scytonema julianum was roughly 30 times higher than that of Scytonema mirabile, which also grew in cave environments, which is due to the characteristics of each site. The entrance of Vapour cave (Spain faces SE, measures 0.75 x 0.6 m and opens to shafts of a total depth of 80 m. Its dimensions and environmental conditions (relative humidity up to 100%; maximum temperature, 43oC imply that it is isolated from external influences, and that the microclimate differs substantially from that experienced externally. Nitrogen fixation, photon flux density, relative humidity and temperature in the Vapor cave were taken hourly over a 24-hour period in winter.

  8. Diffusion air effects on the soot axial distribution concentration in a premixed acetylene/air flame

    Energy Technology Data Exchange (ETDEWEB)

    Fassani, Fabio Luis; Santos, Alex Alisson Bandeira; Goldstein Junior, Leonardo [Universidade Estadual de Campinas, SP (Brazil). Faculdade de Engenharia Mecanica. Dept. de Engenharia Termica e de Fluidos]. E-mails: fassani@fem.unicamp.br; absantos@fem.unicamp.br; leonardo@fem.unicamp.br; Ferrari, Carlos Alberto [Universidade Estadual de Campinas, SP (Brazil). Inst. de Fisica. Dept. de Eletronica Quantica]. E-mail: ferrari@ifi.unicamp.br

    2000-07-01

    Soot particles are produced during the high temperature pyrolysis or combustion of hydrocarbons. The emission of soot from a combustor, or from a flame, is determined by the competition between soot formation and its oxidation. Several factors affect these processes, including the type of fuel, the air-to-fuel ratio, flame temperature, pressure, and flow pattern. In this paper, the influence of the induced air diffusion on the soot axial distribution concentration in a premixed acetylene/air flame was studied. The flame was generated in a vertical axis burner in which the fuel - oxidant mixture flow was surrounded by a nitrogen discharge coming from the annular region between the burner tube and an external concentric tube. The nitrogen flow provided a shield that protected the flame from the diffusion of external air, enabling its control. The burner was mounted on a step-motor driven, vertical translation table. The use of several air-to-fuel ratios made possible to establish the sooting characteristics of this flame, by measuring soot concentration along the flame height with a non-intrusive laser light absorption technique. (author)

  9. Cycloplatinated(II) complexes containing bridging bis(diphenylphosphino)acetylene: Photophysical study

    Energy Technology Data Exchange (ETDEWEB)

    Jamshidi, Mahboubeh [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71467-13565 (Iran, Islamic Republic of); Nabavizadeh, S. Masoud, E-mail: nabavizadeh@shirazu.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71467-13565 (Iran, Islamic Republic of); Sepehrpour, Hajar [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71467-13565 (Iran, Islamic Republic of); Hosseini, Fatemeh Niroomand [Department of Chemistry, Shiraz Branch, Islamic Azad University, Shiraz 71993-37635 (Iran, Islamic Republic of); Kia, Reza [Department of Chemistry, Sharif University of Technology, Tehran 11155-3516 (Iran, Islamic Republic of); Rashidi, Mehdi, E-mail: rashidi@chem.susc.ac.ir [Department of Chemistry, College of Sciences, Shiraz University, Shiraz 71467-13565 (Iran, Islamic Republic of)

    2016-11-15

    Reaction of the known cycloplatinated (II) complexes [PtAr(C^N)(SMe{sub 2})], in which Ar=p–MeC{sub 6}H{sub 4} or p–MeOC{sub 6}H{sub 4} and C^N= 2-phenylpyridinate (ppy) or benzo[h]quinolinate (bhq), with 0.5 equivalent of the bidentate phosphine ligand 1,1′–bis(diphenylphosphino)acetylene, dppac, in acetone at room temperature gave the symmetrical binuclear cycloplatinated(II) complexes [Pt{sub 2}Ar{sub 2}(C^N){sub 2}(μ–dppac)], 1–4, in which dppac acts as a bridging bidentate ligand. All the complexes were fully characterized using multinuclear ({sup 1}H, {sup 31}P and {sup 195}Pt) NMR spectroscopy and the complex [Pt{sub 2}(p–MeC{sub 6}H{sub 4}){sub 2}(ppy){sub 2}(μ–dppac)], 1, was further identified by single crystal X-ray structure determination. Additional information about the geometries and electronic spectra of these cycloplatinated (II) complexes are discussed. Effects of aryl and C^N ligands on the luminescent properties of the complexes were also investigated that are complying well with the related DFT/TD-DFT calculations.

  10. New catalysts for selective hydrogenation of diene and acetylene hydrocarbons into olefins

    Energy Technology Data Exchange (ETDEWEB)

    Frolov, V.M.; Parenago, O.P.; Shuikina, L.P.

    1978-12-01

    New catalysts for selective hydrogenation of diene and acetylene hydrocarbons into olefins were obtained by reacting aqueous palladium, rhodium, or nickel chloride (0.005-0.05 mole/l.) at 50/sup 0/C, in an argon atmosphere with chelating nitrogen compounds, i.e., o-phenanthroline, ..cap alpha..,..cap alpha..'-dipyridyl, sodium ethylenediaminetetracetate, morpholine, branched polyethylene imines, or amino acids such as glycine, ..cap alpha..-alanine, ..beta..-phenyl-..cap alpha..-alanine, tyrosine, or histidine, and treating the complexes so obtained with sodium borohydride at 1:1-1:5 NaBH/sub 4/-metal ratios, in an aqueous medium. Palladium-based complexes showed the highest activities (20-98Vertical Bar3< conversion) and selectivities (98-100Vertical Bar3<) in heterogeneous hydrogenation of cyclopentadiene, butadiene, 1-hexyne, 1,3-cyclohexadiene, or 1,3-cyclooctadiene at 20/sup 0/-60/sup 0/C and 0.5-15 atm hydrogen, carried out in a kinetic circulation reactor or a metallic autoclave. Thus, a catalytic system based on PdCl/sub 2/ and ..beta..-phenyl-..cap alpha..-alanine converted 98Vertical Bar3< of cyclopentadiene to cyclopentene with 99Vertical Bar3< selectivity. The palladium-based catalyst did not deactivate on the contact with air.

  11. Ion enhanced deposition by dual titanium and acetylene plasma immersion ion implantation

    Science.gov (United States)

    Zeng, Z. M.; Tian, X. B.; Chu, P. K.

    2003-01-01

    Plasma immersion ion implantation and deposition (PIII-D) offers a non-line-of-sight fabrication method for various types of thin films on steels to improve the surface properties. In this work, titanium films were first deposited on 9Cr18 (AISI440) stainless bearing steel by metal plasma immersion ion implantation and deposition (MePIII-D) using a titanium vacuum arc plasma source. Afterwards, carbon implantation and carbon film deposition were performed by acetylene (C2H2) plasma immersion ion implantation. Multiple-layered structures with superior properties were produced by conducting Ti MePIII-D + C2H2 PIII successively. The composition and structure of the films were investigated employing Auger electron spectroscopy and Raman spectroscopy. It is shown that the mixing for Ti and C atoms is much better when the target bias is higher during Ti MePIII-D. A top diamond-like carbon layer and a titanium oxycarbide layer are formed on the 9Cr18 steel surface. The wear test results indicate that this dual PIII-D method can significantly enhance the wear properties and decrease the surface friction coefficient of 9Cr18 steel.

  12. Ion enhanced deposition by dual titanium and acetylene plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Zeng, Z.M.; Tian, X.B.; Chu, P.K.

    2003-01-01

    Plasma immersion ion implantation and deposition (PIII-D) offers a non-line-of-sight fabrication method for various types of thin films on steels to improve the surface properties. In this work, titanium films were first deposited on 9Cr18 (AISI440) stainless bearing steel by metal plasma immersion ion implantation and deposition (MePIII-D) using a titanium vacuum arc plasma source. Afterwards, carbon implantation and carbon film deposition were performed by acetylene (C 2 H 2 ) plasma immersion ion implantation. Multiple-layered structures with superior properties were produced by conducting Ti MePIII-D + C 2 H 2 PIII successively. The composition and structure of the films were investigated employing Auger electron spectroscopy and Raman spectroscopy. It is shown that the mixing for Ti and C atoms is much better when the target bias is higher during Ti MePIII-D. A top diamond-like carbon layer and a titanium oxycarbide layer are formed on the 9Cr18 steel surface. The wear test results indicate that this dual PIII-D method can significantly enhance the wear properties and decrease the surface friction coefficient of 9Cr18 steel

  13. Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

    International Nuclear Information System (INIS)

    Cheng, Peifu; Hu, Yun Hang

    2016-01-01

    Graphical abstract: It was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model for C2H2 adsorption on metal-organic frameworks (MOFs), including MOF-5, ZIF-8, HKUST-1, and MIL-53. - Highlights: • Dubinin-Astakhov equation is demonstrated to be a general model for C_2H_2 adsorption on metal-organic frameworks (MOFs). • Surface areas obtained with Dubinin-Astakhov equation from C_2H_2 adsorption on MOFs are consistent with BET surface areas from N_2 adsorption. • C_2H_2 on MOF-5, ZIF-8, and MIL-53 is a physical adsorption, whereas its adsorption on HKUST-1 is due to a chemical bonding. - Abstract: Acetylene (C_2H_2) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C_2H_2 adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C_2H_2 adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C_2H_2 adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C_2H_2 adsorption on those MOFs.

  14. ASD-1000: High-resolution, high-temperature acetylene spectroscopic databank

    Science.gov (United States)

    Lyulin, O. M.; Perevalov, V. I.

    2017-11-01

    We present a high-resolution, high-temperature version of the Acetylene Spectroscopic Databank called ASD-1000. The databank contains the line parameters (position, intensity, Einstein coefficient for spontaneous emission, term value of the lower states, self- and air-broadening coefficients, temperature dependence exponents of the self- and air-broadening coefficients) of the principal isotopologue of C2H2. The reference temperature for line intensity is 296 K and the intensity cutoff is 10-27 cm-1/(molecule cm-2) at 1000 K. The databank has 33,890,981 entries and covers the 3-10,000 cm-1 spectral range. The databank is based on the global modeling of the line positions and intensities performed within the framework of the method of effective operators. The parameters of the effective Hamiltonian and the effective dipole moment operator have been fitted to the observed values of the line positions and intensities collected from the literature. The broadening coefficients as well as their temperature dependence exponents were calculated using the empirical equations. The databank is useful for studying high-temperature radiative properties of C2H2. ASD-1000 is freely accessible via the Internet site of V.E. Zuev Institute of Atmospheric Optics SB RAS ftp://ftp.iao.ru/pub/ASD1000/.

  15. Picosecond phase conjugation in two-photon absorption in poly-di-acetylenes

    International Nuclear Information System (INIS)

    Nunzi, Dominique Jean-Michel

    1990-01-01

    Poly-di-acetylenes exhibit a large two-photon absorption at 1064 nm wavelength. Its different effects on phase-conjugate nonlinearity are described in the framework of picosecond experiments. In solutions, gels, and films (optically thin media), third-order susceptibility appears as an increasing intensity dependent function. Phase measurements by nonlinear interferometry with the substrate or with the solvent are compared with predictions of a resonantly driven three level system. Phase-conjugate response exhibits a multi-exponential decay. Polarization symmetries analysis shows a one-dimensional effect. Study under strong static electric field action reveals that we face charged species bound to photoconductive polymer chains. In PTS single crystals (optically thick media), response saturates and cancels at high light intensity. This is well accounted for by propagation equations solved in large two-photon absorption conditions. The effect is exploited in a phase conjugation experiment under external optical pump excitation. We thus demonstrate that enhanced nonlinearity is a two-photon absorption relayed and amplified by mid-gap absorbing species which have been created by this two-photon absorption. We formally face a four-photon absorption described by a positive imaginary seventh-order non-linearity. (author) [fr

  16. Anion dynamics in the first 10 milliseconds of an argon-acetylene radio-frequency plasma

    International Nuclear Information System (INIS)

    Van de Wetering, F M J H; Beckers, J; Kroesen, G M W

    2012-01-01

    The time evolution of the smallest anions (C 2 H - and H 2 CC - ), just after plasma ignition, is studied by means of microwave cavity resonance spectroscopy (MCRS) in concert with laser-induced photodetachment under varying gas pressure and temperature in an argon-acetylene radio-frequency (13.56 MHz) plasma. These anions act as an initiator for spontaneous dust particle formation in these plasmas. With an intense 355 nm Nd:YAG laser pulse directed through the discharge, electrons are detached only from these anions present in the laser path. This results in a sudden increase in the electron density in the plasma, which can accurately and with sub-microsecond time resolution be measured with MCRS. By adjusting the time after plasma ignition at which the laser is fired through the discharge, the time evolution of the anion density can be studied. We have operated in the linear regime: the photodetachment signal is proportional to the laser intensity. This allowed us to study the trends of the photodetachment signal as a function of the operational parameters of the plasma. The density of the smallest anions steadily increases in the first few milliseconds after plasma ignition, after which it reaches a steady state. While keeping the gas density constant, increasing the gas temperature in the range 30-120 °C limits the number of smallest anions and saturates at a temperature of about 90 °C. A reaction pathway is proposed to explain the observed trends.

  17. Dissociation of Methanol and Acetylene by slow Highly Charged Ion Collision

    International Nuclear Information System (INIS)

    De, Sankar; Rajput, Jyoti; Roy, A; Ahuja, R; Ghosh, P N; Safvan, C P

    2007-01-01

    We report here the results of dissociation of multiple charged methanol and acetylene molecules in collision with 1.2 MeV Ar 8+ projectiles. We observed a wide range of dissociation products from the TOF spectrum starting from undissociated molecular ions, fragments losing an hydrogen atom due to breakage of C-H and/or O-H bonds, to complete rupture of C-C and C-O skeletons for the respective molecules. From the coincidence map of the fragments, we could separate out the different dissociation channels between carbon and oxygen ionic fragments as well as complete two-body dissociation events. The most striking feature in the breakup of CH 3 OH is the formation of H 2 + and H 3 + due to intramolecular rearrangement of the C-H bonds within the methyl group. In dissociative ionization studies of C 2 H 2 , we observed a diatom-like behaviour of the C-C charged complex as evidenced from the measured slopes of the coincidence islands for carbon atomic charged fragments and theoretical values determined from the charge and momentum distribution of the correlated particles. The shape and orientation of the islands give further information about the momentum balance in the fragmentation process in two-body dissociation

  18. Acetylene black incorporated layered copper sulfide nanosheets for high-performance supercapacitor

    International Nuclear Information System (INIS)

    Huang, Ke-Jing; Zhang, Ji-Zong; Jia, Yu-Ling; Xing, Ke; Liu, Yan-Ming

    2015-01-01

    Highlights: • CuS/AB composites were synthesized by a simple solvothermal route. • Supercapacitor electrode based on CuS/AB was fabricated. • Microstructures and electrochemical properties of the electrodes were evaluated. • CuS/AB electrode exhibited ultrahigh specific capacitance and good cycling stability. - Abstract: Two-dimensional transition metal chalcogenides are attracting increasing attention in energy storage due to their unique structures and electronic properties. CuS has been demonstrated with a metal-like electronic conductivity and a high theoretical capacity. In this work, a facile strategy was reported for one-step synthesis of acetylene black (AB) incorporated layered CuS nanosheet via a simple solvothermal route. X-ray diffraction, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy were used to investigate the morphologies and microstructures of the as-prepared materials. Electrochemical data showed that the CuS/AB composites displayed a high specific capacitance of 2981 F/g at 1.0 A/g and retained 64.6% (1924.5 F/g) at a high current density of 20 A/g, indicative of good rate capability. Furthermore, the composites retained approximately 92% of the initial specific capacitance after 600 cycles at a current density of 1.0 A/g, demonstrating good cycling stability. The outstanding electrochemical properties of the CuS/AB composite suggested that it had great potential for practical applications in high-performance supercapacitors and the present synthesis strategy maybe readily extended to the preparation of other composites based on CuS for potential applications in energy storage and conversion devices

  19. The vanadium nitrogenase of Azotobacter chroococcum. Reduction of acetylene and ethylene to ethane.

    Science.gov (United States)

    Dilworth, M J; Eady, R R; Eldridge, M E

    1988-01-01

    1. The vanadium (V-) nitrogenase of Azobacter chroococcum transfers up to 7.4% of the electrons used in acetylene (C2H2) reduction for the formation of ethane (C2H6). The apparent Km for C2H2 (6 kPa) is the same for either ethylene (C2H4) or ethane (C2H6) formation and much higher than the reported Km values for C2H2 reduction to C2H4 by molybdenum (Mo-) nitrogenases. Reduction of C2H2 in 2H2O yields predominantly [cis-2H2]ethylene. 2. The ratio of electron flux yielding C2H6 to that yielding C2H4 (the C2H6/C2H4 ratio) is increased by raising the ratio of Fe protein to VFe protein and by increasing the assay temperature up to at least 40 degrees C. pH values above 7.5 decrease the C2H6/C2H4 ratio. 3. C2H4 and C2H6 formation from C2H2 by V-nitrogenase are not inhibited by H2. CO inhibits both processes much less strongly than it inhibits C2H4 formation from C2H2 with Mo-nitrogenase. 4. Although V-nitrogenase also catalyses the slow CO-sensitive reduction of C2H4 to C2H6, free C2H4 is not an intermediate in C2H6 formation from C2H2. 5. Propyne (CH3C identical to CH) is not reduced by the V-nitrogenase. 6. Some implications of these results for the mechanism of C2H6 formation by the V-nitrogenase are discussed. PMID:3162672

  20. An Ideal Molecular Sieve for Acetylene Removal from Ethylene with Record Selectivity and Productivity.

    Science.gov (United States)

    Li, Bin; Cui, Xili; O'Nolan, Daniel; Wen, Hui-Min; Jiang, Mengdie; Krishna, Rajamani; Wu, Hui; Lin, Rui-Biao; Chen, Yu-Sheng; Yuan, Daqiang; Xing, Huabin; Zhou, Wei; Ren, Qilong; Qian, Guodong; Zaworotko, Michael J; Chen, Banglin

    2017-12-01

    Realization of ideal molecular sieves, in which the larger gas molecules are completely blocked without sacrificing high adsorption capacities of the preferred smaller gas molecules, can significantly reduce energy costs for gas separation and purification and thus facilitate a possible technological transformation from the traditional energy-intensive cryogenic distillation to the energy-efficient, adsorbent-based separation and purification in the future. Although extensive research endeavors are pursued to target ideal molecular sieves among diverse porous materials, over the past several decades, ideal molecular sieves for the separation and purification of light hydrocarbons are rarely realized. Herein, an ideal porous material, SIFSIX-14-Cu-i (also termed as UTSA-200), is reported with ultrafine tuning of pore size (3.4 Å) to effectively block ethylene (C 2 H 4 ) molecules but to take up a record-high amount of acetylene (C 2 H 2 , 58 cm 3 cm -3 under 0.01 bar and 298 K). The material therefore sets up new benchmarks for both the adsorption capacity and selectivity, and thus provides a record purification capacity for the removal of trace C 2 H 2 from C 2 H 4 with 1.18 mmol g -1 C 2 H 2 uptake capacity from a 1/99 C 2 H 2 /C 2 H 4 mixture to produce 99.9999% pure C 2 H 4 (much higher than the acceptable purity of 99.996% for polymer-grade C 2 H 4 ), as demonstrated by experimental breakthrough curves. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Dubinin-Astakhov model for acetylene adsorption on metal-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Cheng, Peifu; Hu, Yun Hang, E-mail: yunhangh@mtu.edu

    2016-07-30

    Graphical abstract: It was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model for C2H2 adsorption on metal-organic frameworks (MOFs), including MOF-5, ZIF-8, HKUST-1, and MIL-53. - Highlights: • Dubinin-Astakhov equation is demonstrated to be a general model for C{sub 2}H{sub 2} adsorption on metal-organic frameworks (MOFs). • Surface areas obtained with Dubinin-Astakhov equation from C{sub 2}H{sub 2} adsorption on MOFs are consistent with BET surface areas from N{sub 2} adsorption. • C{sub 2}H{sub 2} on MOF-5, ZIF-8, and MIL-53 is a physical adsorption, whereas its adsorption on HKUST-1 is due to a chemical bonding. - Abstract: Acetylene (C{sub 2}H{sub 2}) is explosive at a pressure above 29 psi, causing a safety issue for its storage and applications. C{sub 2}H{sub 2} adsorption on metal-organic frameworks (MOFs) has been explored to solve the issue. However, a suitable isotherm equation for C{sub 2}H{sub 2} adsorption on various MOFs has not been found. In this paper, it was demonstrated that Dubinin-Astakhov equation can be exploited as a general isotherm model to depict C{sub 2}H{sub 2} adsorption on MOF-5, ZIF-8, HKUST-1, and MIL-53. In contrast, commonly used Langmuir and BET models exhibited their inapplicability for C{sub 2}H{sub 2} adsorption on those MOFs.

  2. Nuclear magnetic resonance study of the structure of simple molecules adsorbed on metal surfaces: acetylene on platinum

    International Nuclear Information System (INIS)

    Wang, P.K.

    1984-01-01

    We have used NMR to determine the structure of acetylene (HC - CH) adsorbed at room temperature on small platinum particles by studying the 13 C- 13 C, 13 C- 1 H, and 1 H- 1 H dipolar interactions among the nuclei in the adsorbed molecules. We find a model of 77% CCH 2 and 23% HCCH to be the only one consistent with all of our data. The C-C bond length of the majority species, CCH 2 , is determined as 1.44 +- 0.02 A, midway between a single and double bond, suggesting that both carbon atoms bond to the surface. 36 references, 29 figures, 1 table

  3. Acetylene black paste electrode modified with a molecularly imprinted chitosan film for the detection of bisphenol A

    International Nuclear Information System (INIS)

    Deng, Peihong; Xu, Zhifeng; Li, Junhua; Kuang, Yunfei

    2013-01-01

    We report on a voltammetric sensor for bisphenol A (BPA) that is based on an acetylene-black paste electrode modified with a chitosan film molecularly imprinted for BPA. The sensor responds linearly to BPA in the 80 nM to 10 μM concentration range, and the detection limit is 60 nM (at an S/N of 3). The use of a molecular imprint provides an efficient way for eliminating interferences from potentially interfering substances. The high sensitivity, selectivity and stability of the sensor demonstrate its practical application for the determination of BPA in plastic samples. (author)

  4. Synthesis of carbon nanotubes from acetylene on the FeCoMgO catalytic system obtained by ball milling

    Energy Technology Data Exchange (ETDEWEB)

    Biris, A R; Simon, S; Lupu, D; Misan, I [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Biris, A S; Dervishi, E; Li, Z; Watanabe, F [UALR Nanotechnology Center, University of Arkansas, 2801 S University Ave, Little Rock, AR 72204 (United States); Lucaci, M, E-mail: alexandru.biris@itim-cj.r [National Institute for Research and Development in Electrical Engineering ICPE-CA 313 Splaiul Unirii, 030138 Bucharest (Romania)

    2009-08-01

    Highly crystalline multi wall carbon nanotubes have been synthesized by RF-CVD from acetylene at 850{sup 0}C over a Fe:Co:MgO catalyst. The catalytic system was obtained by mixing for 100 h Fe, Co and MgO powders in a ball milling device under petroleum ether environment, followed by oxidation in air at 500{sup 0}C for 24 h. Most of the nanotubes had external diameters in order of dozens of nm and lengths of microns, resulting in an aspect ration of over 1000. Their external to internal diameter ratio varied between 2.5 and 3.

  5. Upconversion enhanced degenerate four-wave mixing in the mid-infrared for sensitive detection of acetylene in gas flows

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Dam, Jeppe Seidelin; Sahlberg, Anna-Lena

    2014-01-01

    We present a new background free method for in situ gas detection that combines degenerate four-wave mixing with an infra-red light detector based on parametric frequency upconversion of infra-red light. The system is demonstrated at mid infrared wavelengths for low concentration measurements...... of acetylene diluted in a N2 gas flow at ambient conditions. It is demonstrated that the system is able to cover more than 100 nm in scanning range and detect concentrations as low as 3 ppm based on the R9e line. A major issue in small signal measurements is scattered light and it is showed how a spatial...

  6. Separation of Acetylene from Carbon Dioxide and Ethylene by a Water-Stable Microporous Metal-Organic Framework with Aligned Imidazolium Groups inside the Channels.

    Science.gov (United States)

    Lee, Jaechul; Chuah, Chong Yang; Kim, Jaheon; Kim, Youngsuk; Ko, Nakeun; Seo, Younggyu; Kim, Kimoon; Bae, Tae Hyun; Lee, Eunsung

    2018-04-24

    Separation of acetylene from carbon dioxide and ethylene is challenging in view of their similar sizes and physical properties. Metal-organic frameworks (MOFs) in general are strong candidates for these separations owing to the presence of functional pore surfaces that can selectively capture a specific target molecule. Here, we report a novel 3D microporous cationic framework named JCM-1. This structure possesses imidazolium functional groups on the pore surfaces and pyrazolate as a metal binding group, which is well known to form strong metal-to-ligand bonds. The selective sorption of acetylene over carbon dioxide and ethylene in JCM-1 was successfully demonstrated by equilibrium gas adsorption analysis as well as dynamic breakthrough measurement. Furthermore, its excellent hydrolytic stability makes the separation processes highly recyclable without a substantial loss in acetylene uptake capacity. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The role of tin-promoted Pd/MWNTs via the management of carbonaceous species in selective hydrogenation of high concentration acetylene

    International Nuclear Information System (INIS)

    Esmaeili, Elaheh; Mortazavi, Yadollah; Khodadadi, Abbas Ali; Rashidi, Ali Morad; Rashidzadeh, Mehdi

    2012-01-01

    Highlights: ► Synthesis of highly active tin-promoted catalysts by polyol method for selective hydrogenation of high concentration of acetylene. ► A positive change in the catalytic activities of tin-promoted catalysts results from distinct geometric and electronic effects. ► Change in the coverage of acetylenic overlayers for different temperature regions corresponds to the change of the number of isolated adsorption sites. ► The isolated adsorption sites are responsible for the enhancement of selectivity to ethylene with increased temperatures, via the management of the carbonaceous species over the catalyst surface. - Abstract: In the present study, Pd/MWNTs are synthesized using polyol process and modified by tin as a promoter for selective hydrogenation of high concentrated acetylene feedstock. Polyol method results in highly dispersed nanoparticles with a depletion of particle size for tin-promoted Pd catalysts as characterized by TEM. Tin promoter plays a considerable role in hydrogenation of pure acetylene stream. This is attributed to formation of Pd 2 Sn structural phase, confirmed by XRD and TPR techniques, composed mainly of intermetallic species. Catalytic behavior of tin-promoted Pd catalysts is affected by geometric and electronic factors which are more pronounced in the case of Sn/Pd = 0.25. A discontinuity in Arrhenius plots for the Sn-promoted catalysts is appeared, which seems to be due to a kinetic factor as a result of change in acetylene coverage on Pd metallic ensembles at low and high temperature ranges. Higher selectivity of the catalysts to ethylene is attributed to the presence of more isolated adsorption sites on the catalyst surface originated from both intermetallic compounds confirmed by XPS and the ones formed via the carbonaceous species upon the acetylene hydrogenation reaction.

  8. Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

    OpenAIRE

    Jiang, Chuanxing; Zhang, Dongzhi; Yin, Nailiang; Yao, Yao; Shaymurat, Talgar; Zhou, Xiaoyan

    2017-01-01

    This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag–SnO2/rGO) nanocomposite film, prepared by layer-by-layer (LbL) self-assembly technology. The as-prepared Ag–SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. A...

  9. Chaos and dynamics on 0.5--300 ps time scales in vibrationally excited acetylene: Fourier transform of stimulated-emission pumping spectrum

    International Nuclear Information System (INIS)

    Pique, J.P.; Chen, Y.; Field, R.W.; Kinsey, J.L.

    1987-01-01

    A recently proposed technique based on the Fourier transform of the spectrum is applied to the stimulated-emission pumping spectrum of acetylene at --26 500 cm/sup -1/ above the vibrational ground state. Correlations on two different time scales (--3 and --45 ps) were found from analysis of low-resolution (0.3 cm/sup -1/) and high-resolution (0.05 cm/sup -1/) spectra, respectively. Additional structure produced dynamic information on a wider (0.5--300 ps) time scale. The results show that acetylene at 26 500 cm/sup -1/ is in the transition from the regular to the chaotic regime

  10. Toward power scaling in an acetylene mid-infrared hollow-core optical fiber gas laser: effects of pressure, fiber length, and pump power

    Science.gov (United States)

    Weerasinghe, H. W. Kushan; Dadashzadeh, Neda; Thirugnanasambandam, Manasadevi P.; Debord, Benoît.; Chafer, Matthieu; Gérôme, Frédéric; Benabid, Fetah; Corwin, Kristan L.; Washburn, Brian R.

    2018-02-01

    The effect of gas pressure, fiber length, and optical pump power on an acetylene mid-infrared hollow-core optical fiber gas laser (HOFGLAS) is experimentally determined in order to scale the laser to higher powers. The absorbed optical power and threshold power are measured for different pressures providing an optimum pressure for a given fiber length. We observe a linear dependence of both absorbed pump energy and lasing threshold for the acetylene HOFGLAS, while maintaining a good mode quality with an M-squared of 1.15. The threshold and mode behavior are encouraging for scaling to higher pressures and pump powers.

  11. Direct synthesis of solid and hollow carbon nanospheres over NaCl crystals using acetylene by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Chandra Kishore, S.; Anandhakumar, S.; Sasidharan, M., E-mail: sasidharan.m@res.srmuniv.ac.in

    2017-04-01

    Highlights: • Hollow and solid carbon nanospheres were synthesized by CVD method. • NaCl was used as template for direct growth of carbon nanospheres. • Separation of NaCl from the mixture is made easy by dissolving in water. • The hollow carbon nanospheres exhibit high specific capacity in Li-ion batteries than the graphite anodes. - Abstract: Carbon nanospheres (CNS) with hollow and solid morphologies have been synthesised by a simple chemical vapour deposition method using acetylene as a carbon precursor. Sodium chloride (NaCl) powder as a template was used for the direct growth of CNS via facile and low-cost approach. The effect of various temperatures (500 °C, 600 °C and 700 °C) and acetylene flow rates were investigated to study the structural evolution on the carbon products. The purified CNS thus obtained was characterized by various physicochemical techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), Raman spectroscopy, and cyclicvoltametry. The synthesised hollow nanospheres were investigated as anode materials for Li-ion batteries. After 25 cycles of repeated charge/discharge cycles, the discharge and charge capacities were found to be 574 mAh/g and 570 mAh/g, respectively which are significantly higher than the commercial graphite samples.

  12. Experimental investigation of timed manifold injection of acetylene in direct injection diesel engine in dual fuel mode

    International Nuclear Information System (INIS)

    Lakshmanan, T.; Nagarajan, G.

    2010-01-01

    The increase in demand and decrease in availability of fossil fuels with more stringent emission norms have led to research in finding an alternative fuel for internal combustion (IC) engines. Among the alternative fuels, gaseous fuels find a great potential. The gaseous fuel taken up for the present study is acetylene, which possesses excellent combustion properties. Preignition is the major problem with this fuel. In the present study, timed manifold injection technique is adopted to induct the fuel into the IC engine. A four-stroke, 4.4 kW diesel engine is selected, with slight modification in intake manifold for holding the gas injector, which is controlled by an electronic control unit (ECU). By using an ECU, an optimized injection timing of 10 o after top dead center and 90 o crank angle duration are arrived. At this condition, experiments were conducted for the various gas flow rates of 110 g/s, 180 g/s and 240 g/s. The performance was nearer to diesel at full load. Oxides of nitrogen, hydrocarbon and carbon monoxide emission decreased due to lean operation with marginal increase in smoke emission. To conclude, a safe operation of acetylene replacement up to 24% was possible with reduction in emission parameters.

  13. Al or Si decorated graphene-oxide: A promising material for capture and activation of ethylene and acetylene

    Science.gov (United States)

    Esrafili, Mehdi D.; Dinparast, Leila

    2018-06-01

    In this work, quantum chemical calculations are performed to compare adsorption behavior of ethylene and acetylene molecules over Al- or Si-decorated graphene oxide (Al/Si-GO). The corresponding adsorption energies, geometrical parameters and net charge-transfer values are calculated using the dispersion-corrected DFT calculations. The obtained large adsorption energies of the Al and Si atoms over GO suggest that both Al-GO and Si-GO are stable enough to be used as a stable substrate to capture and activate ethylene or acetylene. The results show that the adsorption of C2H4 or C2H2 on Al-GO is more favorable than over Si-GO surface, mainly due to the orbital interactions between the adsorbate and surface. Also, the DFT calculations reveal that the interaction of C2H2 with both surfaces is stronger than that of C2H4. Our findings are applicable for future theoretical and experimental studies about the interaction of hydrocarbons with light metal decorated graphene-based materials as well as heterogeneous catalysis.

  14. Rapid analysis of dissolved methane, ethylene, acetylene and ethane using partition coefficients and headspace-gas chromatography.

    Science.gov (United States)

    Lomond, Jasmine S; Tong, Anthony Z

    2011-01-01

    Analysis of dissolved methane, ethylene, acetylene, and ethane in water is crucial in evaluating anaerobic activity and investigating the sources of hydrocarbon contamination in aquatic environments. A rapid chromatographic method based on phase equilibrium between water and its headspace is developed for these analytes. The new method requires minimal sample preparation and no special apparatus except those associated with gas chromatography. Instead of Henry's Law used in similar previous studies, partition coefficients are used for the first time to calculate concentrations of dissolved hydrocarbon gases, which considerably simplifies the calculation involved. Partition coefficients are determined to be 128, 27.9, 1.28, and 96.3 at 30°C for methane, ethylene, acetylene, and ethane, respectively. It was discovered that the volume ratio of gas-to-liquid phase is critical to the accuracy of the measurements. The method performance can be readily improved by reducing the volume ratio of the two phases. Method validation shows less than 6% variation in accuracy and precision except at low levels of methane where interferences occur in ambient air. Method detection limits are determined to be in the low ng/L range for all analytes. The performance of the method is further tested using environmental samples collected from various sites in Nova Scotia.

  15. Pressure-induced amorphization and reactivity of solid dimethyl acetylene probed by in situ FTIR and Raman spectroscopy

    Science.gov (United States)

    Guan, Jiwen; Daljeet, Roshan; Kieran, Arielle; Song, Yang

    2018-06-01

    Conjugated polymers are prominent semiconductors that have unique electric conductivity and photoluminescence. Synthesis of conjugated polymers under high pressure is extremely appealing because it does not require a catalyst or solvent used in conventional chemical methods. Transformation of acetylene and many of its derivatives to conjugated polymers using high pressure has been successfully achieved, but not with dimethyl acetylene (DMA). In this work, we present a high-pressure study on solid DMA using a diamond anvil cell up to 24.4 GPa at room temperature characterized by in situ Fourier transform infrared and Raman spectroscopy. Our results show that solid DMA exists in a phase II crystal structure and is stable up to 12 GPa. Above this pressure, amorphization was initiated and the process was completed at 24.4 GPa. The expected polymeric transformation was not evident upon compression, but only observed upon decompression from a threshold compression pressure (e.g. 14.4 GPa). In situ florescence measurements suggest excimer formation via crystal defects, which induces the chemical reactions. The vibrational spectral analysis suggests the products contain the amorphous poly(DMA) and possibly additional amorphous hydrogenated carbon material.

  16. Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

    Directory of Open Access Journals (Sweden)

    Chuanxing Jiang

    2017-09-01

    Full Text Available This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag–SnO2/rGO nanocomposite film, prepared by layer-by-layer (LbL self-assembly technology. The as-prepared Ag–SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM, transmission electron microscopy (TEM, X-ray diffraction (XRD and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. An optimal temperature of 90 °C was determined, and the Ag–SnO2/rGO nanocomposite sensor exhibited excellent sensing behaviors towards acetylene, in terms of response, repeatability, stability and response/recovery characteristics, which were superior to the pure SnO2 and SnO2/rGO film sensors. The sensing mechanism of the Ag–SnO2/rGO sensor was attributed to the synergistic effect of the ternary nanomaterials, and the heterojunctions created at the interfaces between SnO2 and rGO. This work indicates that the Ag–SnO2/rGO nanocomposite is a good candidate for constructing a low-temperature acetylene sensor.

  17. Acetylene Gas-Sensing Properties of Layer-by-Layer Self-Assembled Ag-Decorated Tin Dioxide/Graphene Nanocomposite Film

    Science.gov (United States)

    Jiang, Chuanxing; Yin, Nailiang; Yao, Yao; Shaymurat, Talgar; Zhou, Xiaoyan

    2017-01-01

    This paper demonstrates an acetylene gas sensor based on an Ag-decorated tin dioxide/reduced graphene oxide (Ag–SnO2/rGO) nanocomposite film, prepared by layer-by-layer (LbL) self-assembly technology. The as-prepared Ag–SnO2/rGO nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectrum. The acetylene sensing properties were investigated using different working temperatures and gas concentrations. An optimal temperature of 90 °C was determined, and the Ag–SnO2/rGO nanocomposite sensor exhibited excellent sensing behaviors towards acetylene, in terms of response, repeatability, stability and response/recovery characteristics, which were superior to the pure SnO2 and SnO2/rGO film sensors. The sensing mechanism of the Ag–SnO2/rGO sensor was attributed to the synergistic effect of the ternary nanomaterials, and the heterojunctions created at the interfaces between SnO2 and rGO. This work indicates that the Ag–SnO2/rGO nanocomposite is a good candidate for constructing a low-temperature acetylene sensor. PMID:28927021

  18. Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

    KAUST Repository

    Sajid, Muhammad Bilal; Es-sebbar, Et-touhami; Farooq, Aamir

    2014-01-01

    Linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene have been measured at 296K in the P branch of the ν4+ν5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296-683K for five

  19. Autoxidation and acetylene-accelerated oxidation of NO in a 2-phase system; implications for the expression of denitrification in ex situ experiments

    Science.gov (United States)

    Nadeem, Shahid; Dörsch, Peter; Bakken, Lars

    2013-04-01

    Denitrification allows microorganisms to sustain respiration under anoxic conditions. The typical niche for denitrification is an environment with fluctuating oxygen concentrations such as soils and borders between anoxic and oxic zones of biofilms and sediments. In such environments, the organisms need adequate regulation of denitrification in response to changing oxygen availability to tackle both oxic and anoxic spells. The regulation of denitrification in soils has environmental implications, since it affects the proportions of N2, N2O and NO emitted to the atmosphere. The expression of denitrification enzymes is regulated by a complex regulatory network involving one or several positive feedback loops via the intermediate nitrogen oxides. Nitric oxide (NO) is known to induce denitrification in model organisms, but the quantitative effect of NO and its concentration dependency has not been assessed for denitrification in soils. NO is chemically unstable in the presence of oxygen due to autoxidation, and the oxidation of NO is accelerated by acetylene (C2H2) which is commonly used as an inhibitor of N2O reductase in denitrification studies. As a first step to a better understanding of NO's role in soil denitrification, we investigated NO oxidation kinetics for a closed "two phase" system (i.e. liquid phase + headspace) typically used for denitrification experiments with soil slurries, with and without acetylene present. Models were developed to adequately predict autoxidation and acetylene-accelerated oxidation. The minimum oxygen concentration in the headspace ([O2]min, mL L-1) for acetylene-accelerated NO oxidation was found to increase linearly with the NO concentration ([NO], mL L-1); [O2]min= 0.192 + [NO]*0.1 (r2=0.978). The models for NO oxidation were then used to assess NO-oxidation rates in denitrification experiments with batches of bacterial cells extracted from soil. The batches were exposed to low initial oxygen concentrations in gas tight serum

  20. Influence of soil composition in the determination of chromium by atomic absorption spectrometry with flame air / acetylene; Influencia de la composicion del suelo en la determinacion de cromo por espectrometria de absorcion atomica con llama aire/acetileno

    Energy Technology Data Exchange (ETDEWEB)

    Duran Sosa, Ibis; Granda Valdes, Mayra [Departamento de Quimica Analitica, Facultad de Quimica, Universidad de La Habana, La Habana (Cuba); Pomares Alfonso, Mario Simeon, E-mail: mpomares@imre.oc.uh.cu [Instituto de Ciencias y Tecnologia de Materiales, Universidad de La Habana, La Habana (Cuba)

    2014-07-01

    The Air-acetylene Flame Atomic Absorption determination of chromium is a complex task, being strongly influenced by sample composition and instrumental conditions. The objective of this work was to study the influence of Al, Ca, Fe, K, Mg, and Na on the absorption of chromium in the air-acetylene flame, both separately and combined in solution, when acetylene flow and burner height vary. Dissolutions of the mixtures simulated the composition of four soils from the Quibu River Basin in Havana, Cuba. Chromium absorption first increased and then decreased with increment of acetylene flow for shorter burner heights (∼ 2-4 mm); while a continuous increase was observed for larger heights (> 4 mm). This behavior was the same in the presence and absence of interfering chemical element, mentioned above. On the other hand, the dependence of the magnitude of the interference with acetylene flow and burner height was complex and dependent on the interfering element, particularly at larger heights where the behavior of Al was remarkably different. The interference of the four mixtures of Al, Ca, K, Fe, Mg and Na decreased in comparison to individual interfering effects and was less dependent on acetylene flow and burner height. Finally, a significant reduction of interference on chromium determination in soil samples was achieved by an adequate selection of acetylene flow and burner height.

  1. Effects of acetylene and carbon monoxide on long-term hydrogen production by Mastigocladus laminosus, a thermophilic blue-green alga

    Energy Technology Data Exchange (ETDEWEB)

    Miura, Y; Yokoyama, H; Takahara, K; Miyamoto, K

    1982-01-01

    Long-term H/sub 2/ production by a thermophilic and heterocystous blue-green alga (cyanobacterium) Mastigocladus laminosus was studied under the conditions when acetylene and carbon monoxide were supplemented to the gas phase of the culture vessel. The addition of both gases enhanced H/sub 2/ evolution by nitrogen-starved cells. The concentrations of acetylene and carbon monoxide in the gas phase of argon/CO/sub 2/ (97.5/2.5) were 10% and 0.2 to 1%, respectively, for the maximum H/sub 2/ production. Renewals of the gas phase, in addition to the addition of acetylene and carbon monoxide, were necessary for durable H/sub 2/ production. Since the concentrations of both H/sub 2/ and O/sub 2/ accumulated in the gas phase were minimized after the renewals, the H/sub 2/ uptake activity, which was not completely inhibited by acetylene and carbon monoxide, was reduced and thereby H/sub 2/ evolution was restored. Under such conditions, H/sub 2/ production for up to 20 days was observed under argon and N/sub 2/ atmospheres with average rats of 3.9 and 3.3..mu..l/mg dry wt/h, respectively. H/sub 2/ evolution for 15 days was observed even under an air atmosphere containing acetylene and carbon monoxide. It was thus shown that prolonged production of H/sub 2/ was possible by the use of a blue-green alga which exhibits a high activity of H/sub 2/ uptake under nitrogen-starved conditions.

  2. Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene.

    Science.gov (United States)

    Kaspar, H F; Tiedje, J M

    1981-03-01

    15N tracer methods and gas chromatography coupled to an electron capture detector were used to investigate dissimilatory reduction of nitrate and nitrite by the rumen microbiota of a fistulated cow. Ammonium was the only 15N-labeled end product of quantitative significance. Only traces of nitrous oxide were detected as a product of nitrate reduction; but in experiments with nitrite, up to 0.3% of the added nitrogen accumulated as nitrous oxide, but it was not further reduced. Furthermore, when 13NO3- was incubated with rumen microbiota virtually no [13N]N2 was produced. Acetylene partially inhibited the reduction of nitrite to ammonium as well as the formation of nitrous oxide. It is suggested that in the rumen ecosystem nitrous oxide is a byproduct of dissimilatory nitrite reduction to ammonium rather than a product of denitrification and that the latter process is absent from the rumen habitat.

  3. Selective hydrogenation of acetylene on SiO{sub 2} supported Ni-In bimetallic catalysts: Promotional effect of In

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Yanjun; Chen, Jixiang, E-mail: jxchen@tju.edu.cn

    2016-11-30

    Graphical abstract: A suitable Ni/In ratio remarkably enhanced the acetylene conversion, the selectivity to ethylene and the catalyst stability. Display Omitted - Highlights: • There was a promotional effect of In on the performance of Ni/SiO{sub 2}. • A suitable Ni/In ratio was required for good performance of Ni{sub x}In/SiO{sub 2}. • Both geometrical and electronic effects of In contributed to good performance. • Ni/SiO{sub 2} deactivation is mainly owing to phase change from Ni to nickel carbide. • The carbonaceous deposit was the main reason for Ni{sub x}In/SiO{sub 2} deactivation. - Abstract: Ni/SiO{sub 2} and the bimetallic Ni{sub x}In/SiO{sub 2} catalysts with different Ni/In ratios were tested for the selective hydrogenation of acetylene, and their physicochemical properties before and after the reaction were characterized by means of N{sub 2}-sorption, H{sub 2}-TPR, XRD, TEM, XPS, H{sub 2} chemisorption, C{sub 2}H{sub 4}-TPD, NH{sub 3}-TPD, FT-IR of adsorbed pyridine, and TG/DTA and Raman. A promotional effect of In on the performance of Ni/SiO{sub 2} was found, and Ni{sub x}In/SiO{sub 2} with a suitable Ni/In ratio gave much higher acetylene conversion, ethylene selectivity and catalyst stability than Ni/SiO{sub 2}. This is ascribed to the geometrical isolation of the reactive Ni atoms with the inert In ones and the charge transfer from the In atoms to Ni ones, both of which are favorable for reducing the adsorption strength of ethylene and restraining the C−C hydrogenolysis and the polymerizations of acetylene and the intermediate compounds. On the whole, Ni{sub 6}In/SiO{sub 2} and Ni{sub 10}In/SiO{sub 2} had better performance. Nevertheless, with increasing the In content, the selectivity to the C4+ hydrocarbons tended to increase due to the enhanced catalyst acidity because of the charge transfer from the In atoms to Ni ones. As the Lewis acid ones, the In sites could promote the polymerization. The catalyst deactivation was also analyzed

  4. Metastable argon atom density in complex argon/acetylene plasmas determined by means of optical absorption and emission spectroscopy

    International Nuclear Information System (INIS)

    Sushkov, Vladimir; Herrendorf, Ann-Pierra; Hippler, Rainer

    2016-01-01

    Optical emission and absorption spectroscopy has been utilized to investigate the instability of acetylene-containing dusty plasmas induced by growing nano-particles. The density of Ar(1s 5 ) metastable atoms was derived by two methods: tunable diode laser absorption spectroscopy and with the help of the branching ratio method of emitted spectral lines. Results of the two techniques agree well with each other. The density of Ar(1s 3 ) metastable atoms was also measured by means of optical emission spectroscopy. The observed growth instability leads to pronounced temporal variations of the metastable and other excited state densities. An analysis of optical line ratios provides evidence for a depletion of free electrons during the growth cycle but no indication for electron temperature variations. (paper)

  5. Measurements of linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene in the ν4+ν5 combination band using a cw quantum cascade laser

    KAUST Repository

    Sajid, Muhammad Bilal

    2014-11-01

    Linestrengths, N2-, Ar-, He- and self-broadening coefficients of acetylene have been measured at 296K in the P branch of the ν4+ν5 combination band for 25 rotational transitions. The effect of gas temperature is studied over 296-683K for five transitions to allow the determination of the temperature dependent exponent n for N2- and Ar-broadening coefficients. These measurements were performed using a continuous-wave quantum cascade laser (cw-QCL) operating over 1253-1310cm-1. Spectroscopic parameters were obtained by fitting absorption spectra using Voigt, Galatry and Rautian profiles. Linestrength and broadening results are compared with previous studies available in literature for the ν4+ν5 combination band and other vibrational bands of acetylene. © 2014 Elsevier Ltd.

  6. Momentum-imaging investigations of the dissociation of D2+ and the isomerization of acetylene to vinylidene by intense short laser pulses

    International Nuclear Information System (INIS)

    Alnaser, A S; Litvinyuk, I; Osipov, T; Ulrich, B; Landers, A; Wells, E; Maharjan, C M; Ranitovic, P; Bochareva, I; Ray, D; Cocke, C L

    2006-01-01

    We present momentum images of the ionic products from the ionization of D 2 and C 2 H 2 by short laser pulses. For D 2 , we use a pump-probe approach to investigate the dependence of the enhanced ionization on the internuclear distance. Evidence for two (not well separated) regions of enhancement is found near internuclear distances of 6 and 10 au. In the case of acetylene, we report clear evidence for the production of both acetylene and vinylidene dications with kinetic energy releases similar to those reported earlier by core electron removal. We also find very different angular distributions for the fragments in the two channels, consistent with a finite time for the isomerization

  7. Self-broadening coefficients and positions of acetylene around 1.533 μm studied by high-resolution diode laser absorption spectrometry

    International Nuclear Information System (INIS)

    Li Jingsong; Durry, Georges; Cousin, Julien; Joly, Lilian; Parvitte, Bertrand; Zeninari, Virginie

    2010-01-01

    The self-broadening coefficients of acetylene at room temperature have been measured for 10 lines in the P branch of the ν 1 +ν 3 (Σ u + )-0(Σ g + ) bands of 12 C 2 H 2 and 13 C 12 CH 2 near 1.533 μm, using a high resolution tunable diode laser spectrometer developed for the Martian space mission PHOBOS-Grunt. The collisional widths are obtained by fitting each recorded line with the Voigt profile as well as the Rautian profile accounting for the collisional Dicke narrowing effect. The standard Voigt model provides slightly smaller broadening coefficients than the Rautian model. Our data are thoroughly compared to the main atmospheric molecule database HITRAN and previous values in various bands of acetylene. Moreover, it is worth noting that a large number of new transitions not listed in the latest HITRAN08 were measured and identified for the first time.

  8. Characterization and reaction studies of dimeric molybdenum(III) complexes with bridging dithiolate ligands. Catalytic reduction of acetylene to ethylene

    International Nuclear Information System (INIS)

    DuBois, M.R.; Haltiwanger, R.C.; Miller, D.J.; Glatzmaier, G.

    1979-01-01

    The complexes [C 5 H 5 MoSC/sub n/H/sub 2n/S] 2 (where n = 2 and 3) have been prepared by the reaction of ethylene sulfide and propylene sulfide, respectively, with C 5 H 5 MoH(CO) 3 or with [C 5 H 5 Mo(CO) 3 ] 2 . Cyclic voltammetry shows that each complex undergoes two reversible oxidations at 0.13 and 0.79 V vs. SCE (in acetonitrile with 0.1 M Bu 4 NBF 4 ). Both the one-electron and two-electron oxidation products have been synthesized and characterized by spectral and magnetic data. Electrochemical data for the oxidized complexes support the conclusion that the complexes have the same gross structural features in all three oxidation states. A single crystal of the monocation [C 5 H 5 MoSC 3 H 6 S] 2 BF 4 has been characterized by an x-ray diffraction study. The compound crystallizes in the space group C2/c with a = 18.266 (1) A, b = 9.206 (4) A, c = 12.911 (5) A, β = 100.83 (3) 0 , and V = 2128 A 3 . The metal ions of the cation are bridged by two 1,2-propanedithiolate ligands. The four sulfur atoms of these ligands form a plane which bisects the metal-metal distance. The neutral dimeric complexes undergo a unique reaction with alkenes and alkynes in which the hydrocarbon portion of the bridging dithiolate ligands is exchanged. The reaction has been characterized with olefinswith both electron-withdrawing and electron-donating substituents. When [C 5 H 5 MoSC 2 H 4 S] 2 (1) is reacted with acetylene at 25 0 C, ethene is produced and the complex [C 5 H 5 MoSC 2 H 2 S] 2 is isolated. The latter complex is reduced by hydrogen (2 atm) at 60 0 C to re-form 1. The utility of these reactions in the catalytic reduction of acetylene to ethylene has been investigated. The role of the sulfur ligands in this catalytic cycle is discussed. 50 references, 2 figures, 5 tables

  9. Mechanism-based inactivation of cytochrome P-450 dependent benzo[a]pyrene hydroxylase activity by acetylenic and olefinic polycyclic arylhydrocarbons

    International Nuclear Information System (INIS)

    Gan, L.S.

    1986-01-01

    A series of aryl acetylenes and aryl olefins have been examined as substrates and inhibitors of cytochrome P-450 dependent monooxygenases in liver microsomes from 5,6-benzoflavone or phenobarbital pretreated rats. 1-Ethynylpyrene (EP), 3-ethynylperylene (EPL), cis- and trans-1-(2-bromo-vinyl)pyrene (c-BVP and t-BVP), and 1-allylpyrene (AP) serve as mechanism-based irreversible inactivators (suicide inhibitors) of benzo(a)pyrene (BP) hydroxylase, while 1-vinyl-pyrene (VP) and phenyl 1-pyrenyl acetylene (PPA) do not cause a detectable suicide inhibition of the BP hydroxylase. The mechanism-based loss of BP hydroxylase activity caused by the aryl acetylenes is not accompanied by a corresponding loss of the P-450 content of the microsomes. In the presence of NADPH, 3 H-labeled EP covalently attached to P-450 isozymes with a measured stoichiometry of one mole of EP per mole of the P-450 heme. The results of the effects of these aryl derivatives in the mammalian cell-mediated mutagenesis assay and toxicity assay show that none of the compounds examined nor any of the their metabolites produced in the incubation system are cytotoxic to V79 cells

  10. Shock tube/laser absorption measurements of methane, acetylene and ethylene during the pyrolysis of n-pentane and iso-pentane

    KAUST Repository

    Sajid, Muhammad Bilal

    2015-11-09

    Pentane isomers are important constituents of distillate gasoline, compressed natural gas and liquefied petroleum gas. Pentane chemistry is integral component of the chemical kinetic mechanisms of larger hydrocarbons. Existing kinetic mechanisms differ in their predictions of the oxidative and pyrolysis behavior of pentane isomers. This work provides new species time-history data to validate and improve pentane chemistry models. Methane, acetylene and ethylene are measured during the high-temperature pyrolysis of n-pentane and iso-pentane. Experiments are performed behind reflected shock waves over 1400–2100 K and pressures near 1 atm. Methane and acetylene are measured using a quantum cascade laser operating near 8 µm, whereas ethylene is measured with a CO2 gas laser operating near 10.6 µm. A two-color technique is used to eliminate broadband interference caused by large hydrocarbons. Measurements are compared with predictions of existing chemical kinetic mechanisms which underpredict the formation of methane and acetylene but overpredict ethylene formation.

  11. Studies on synthesis and hydrogenation behaviour of graphitic nanofibres prepared through palladium catalyst assisted thermal cracking of acetylene

    International Nuclear Information System (INIS)

    Gupta, Bipin Kumar; Tiwari, R.S.; Srivastava, O.N.

    2004-01-01

    The nano-variants of carbon including graphitic nanofibres (GNF) have recently been considered to be exotic (light weight, high storage capacity) hydrogen storage materials. In the present paper, we report growth of aligned bundles of GNF. The length and width of cross-section of the bundles is ∼50 and ∼25 μm, respectively. The length of individual GNF is ∼50 μm and diameter ∼0.25 μm. The GNFs have been synthesized through thermal decomposition of acetylene using palladium (Pd) sheets as catalyst. This represents a new form of catalyst. The GNFs bundles grown by the present method are easier to hydrogenate. They adsorb hydrogen at a lower pressure of ∼80 atm as against ∼120 atm for the GNF grown in the earlier studies. The storage capacity obtained in the present investigation is ∼17 wt.%. Electron microscopic investigations reveal that as against the as grown GNF, the hydrogenated version embodies microstructures exhibiting fragmentation of graphitic layer bundles. The reasons for the growth of GNF in the form of aligned bundles, the ease of hydrogenation and relevance of GNF fragmentation after hydrogenation have been outlined

  12. Superior mercury-free catalysts for acetylene hydrochlorination to VCM. Achieving high productivities and long catalyst life-time

    Energy Technology Data Exchange (ETDEWEB)

    Liebens, A.T.; Piccinini, M. [Solvay S.A., Bruxelles (Belgium)

    2013-11-01

    New mercury-free catalytic systems based on the use of ionic liquids (IL) and noble metals (e.g. Pd, Au) have been evaluated for the hydrochlorination reaction of acetylene to produce Vinyl Chloride Monomer (VCM). Two different approaches have been investigated: gas-liquid homogeneous catalytic systems in the presence of molten IL/Metal and heterogeneous gas-solid ones using solid materials. For the latter case, very positive results have been obtained using SILP-type catalysts (SILP: Supported Ionic Liquid Phase) where IL/Metal were deposited onto a solid mesoporous support. Remarkably, both systems display very high Space Time Yield (STY) and breakthrough life-time stability. No deactivation is observed even after 500 h on stream indicating the strong advantages of these new materials compared to most investigated Au/C supported systems. The development of heterogeneous catalysts was preferred as the scale-up of gas-liquid technology implies important CAPEX investments to convert current plants from gas-solid to gas-liquid equipment. (orig.)

  13. Studies on synthesis and hydrogenation behaviour of graphitic nanofibres prepared through palladium catalyst assisted thermal cracking of acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Bipin Kumar; Tiwari, R.S.; Srivastava, O.N

    2004-11-03

    The nano-variants of carbon including graphitic nanofibres (GNF) have recently been considered to be exotic (light weight, high storage capacity) hydrogen storage materials. In the present paper, we report growth of aligned bundles of GNF. The length and width of cross-section of the bundles is {approx}50 and {approx}25 {mu}m, respectively. The length of individual GNF is {approx}50 {mu}m and diameter {approx}0.25 {mu}m. The GNFs have been synthesized through thermal decomposition of acetylene using palladium (Pd) sheets as catalyst. This represents a new form of catalyst. The GNFs bundles grown by the present method are easier to hydrogenate. They adsorb hydrogen at a lower pressure of {approx}80 atm as against {approx}120 atm for the GNF grown in the earlier studies. The storage capacity obtained in the present investigation is {approx}17 wt.%. Electron microscopic investigations reveal that as against the as grown GNF, the hydrogenated version embodies microstructures exhibiting fragmentation of graphitic layer bundles. The reasons for the growth of GNF in the form of aligned bundles, the ease of hydrogenation and relevance of GNF fragmentation after hydrogenation have been outlined.

  14. A DFT study on the mechanisms for the cycloaddition reactions between 1-aza-2-azoniaallene cations and acetylenes.

    Science.gov (United States)

    Wang, Jing-mei; Li, Zhi-ming; Wang, Quan-rui; Tao, Feng-gang

    2013-01-01

    The mechanisms of cycloaddition reactions between 1-aza-2-azoniaallene cations 1 and acetylenes 2 have been investigated using the global electrophilicity and nucleophilicity of the corresponding reactants as global reactivity indexes defined within the conceptual density functional theory. The reactivity and regioselectivity of these reactions were predicted by analysis of the energies, geometries, and electronic nature of the transition state structures. The theoretical results revealed that the reaction features a tandem process: an ionic 1,3-dipolar cycloaddition to produce the cycloadducts 3 H-pyrazolium salts 3 followed by a [1,2]-shift affording the thermodynamically more stable adducts 4 or 5. The mechanism of the cycloaddition reactions can be described as an asynchronous concerted pathway with reverse electron demand. The model reaction has also been investigated at the QCISD/6-31++G(d,p) and CCSD(T)/6-31++G(d,p)//B3LYP/6-31++G(d,p) levels as well as by the DFT. The polarizable continuum model, at the B3LYP/6-31++G(d,p) level of theory, was used to study solvent effects on all the studied reactions. In solvent dichloromethane, all the initial cycloadducts 3 were obtained via direct ionic process as the result of the solvent effect. The consecutive [1,2]-shift reaction, in which intermediates 3 are rearranged to the five-membered heterocycles 4/5, is proved to be a kinetically controlled reaction, and the regioselectivity can be modulated by varying the migrant. The LOL function and RDG function based on localized electron analysis were used to analysis the covalent bond and noncovalent interactions in order to unravel the mechanism of the title reactions.

  15. Third-order nonlinear optical properties of open-shell supermolecular systems composed of acetylene linked phenalenyl radicals.

    Science.gov (United States)

    Nakano, Masayoshi; Kishi, Ryohei; Yoneda, Kyohei; Inoue, Yudai; Inui, Tomoya; Shigeta, Yasuteru; Kubo, Takashi; Champagne, Benoît

    2011-08-11

    The third-order nonlinear optical (NLO) properties, at the molecular level, the static second hyperpolarizabilities, γ, of supermolecular systems composed of phenalenyl and pyrene rings linked by acetylene units are investigated by employing the long-range corrected spin-unrestricted density functional theory, LC-UBLYP, method. The phenalenyl based superethylene, superallyl, and superbutadiene in their lowest spin states have intermediate diradical characters and exhibit larger γ values than the closed-shell pyrene based superpolyene systems. The introduction of a positive charge into the phenalenyl based superallyl radical changes the sign of γ and enhances its amplitude by a factor of 35. Although such sign inversion is also observed in the allyl radical and cation systems in their ground state equilibrium geometries, the relative amplitude of γ is much different, that is, |γ(regular allyl cation)/γ(regular allyl radical)| = 0.61 versus |γ(phenalenyl based superallyl cation)/γ(phenalenyl based superallyl radical)| = 35. In contrast, the model ethylene, allyl radical/cation, and butadiene systems with stretched carbon-carbon bond lengths (2.0 Å), having intermediate diradical characters, exhibit similar γ features to those of the phenalenyl based superpolyene systems. This exemplifies that the size dependence of γ as well as its sign change by introducing a positive charge on the phenalenyl based superpolyene systems originate from their intermediate diradical characters. In addition, the change from the lowest to the highest π-electron spin states significantly reduces the γ amplitudes of the neutral phenalenyl based superpolyene systems. For phenalenyl based superallyl cation, the sign inversion of γ (from negative to positive) is observed upon switching between the singlet and triplet states, which is predicted to be associated with a modification of the balance between the positive and negative contributions to γ. The present study paves the way

  16. Role of Fluid-Dynamics in Soot Formation and Microstructure in Acetylene-Air Laminar Diffusion Flames

    Directory of Open Access Journals (Sweden)

    Praveen Pandey

    2015-03-01

    Full Text Available Residence time and thermo-chemical environment are important factors in the soot-formation process in flames. Studies have revealed that flow-dynamics plays a dominant role in soot formation process. For understanding the effect of flow dynamics on soot formation and physical structure of the soot formed in different combustion environments two types of laminar diffusion flames of Acetylene and air, a normal diffusion flame (NDF and an inverse diffusion flame (IDF have been investigated. The fuel and air supply in the reaction zone in two flame types were kept constant but the interchange of relative position of fuel and air altered the burner exit Reynolds and Froude numbers of gases, fuel/air velocity ratio and flame shape. Soot samples were collected using thermophoretic sampling on transmission electron microscope (TEM grids at different flame heights and were analyzed off-line in a Transmission Electron Microscope. Soot primary particle size, soot aggregate size and soot volume fraction were measured using an image analysis software. In NDF the maximum flame temperature was about 1525 K and 1230 K for IDF. The soot primary particles are distinctly smaller in size in IDF (between 19 – 26 nm compared to NDF (between 29–34 nm. Both NDF and IDF show chainlike branched structure of soot agglomerate with soot particles of a nearly spherical shape. The average number of soot primary particles per aggregate in NDF was in the range of 24 to 40 and in IDF it varied between 16 to 24. Soot volume fraction was between 0.6 to 1.5 ppm in NDF where as it was less than 0.2 ppm in IDF. The change in sooting characteristics of the two flame types is attributed to changed fuel/air velocity ratio, entrainment of gas molecules and thermophoresis on soot particles.

  17. An empirical spectroscopic database for acetylene in the regions of 5850-6341 cm-1 and 7000-9415 cm-1

    Science.gov (United States)

    Lyulin, O. M.; Campargue, A.

    2017-12-01

    Six studies have been recently devoted to a systematic analysis of the high-resolution near infrared absorption spectrum of acetylene recorded by Cavity Ring Down spectroscopy (CRDS) in Grenoble and by Fourier-transform spectroscopy (FTS) in Brussels and Hefei. On the basis of these works, in the present contribution, we construct an empirical database for acetylene in the 5850-9415 cm-1 region excluding the 6341-7000 cm-1 interval corresponding to the very strong ν1+ν3 manifold. Our database gathers and extends information included in our CRDS and FTS studies. In particular, the intensities of about 1700 lines measured by CRDS in the 7244-7920 cm-1 region are reported for the first time together with those of several bands of 12C13CH2 present in natural isotopic abundance in the acetylene sample. The Herman-Wallis coefficients of most of the bands are derived from a fit of the measured intensity values. A recommended line list is provided with positions calculated using empirical spectroscopic parameters of the lower and upper energy vibrational levels and intensities calculated using the derived Herman-Wallis coefficients. This approach allows completing the experimental list by adding missing lines and improving poorly determined positions and intensities. As a result the constructed line list includes a total of 11113 transitions belonging to 150 bands of 12C2H2 and 29 bands of 12C13CH2. For comparison the HITRAN database in the same region includes 869 transitions of 14 bands, all belonging to 12C2H2. Our weakest lines have an intensity on the order of 10-29 cm/molecule, about three orders of magnitude smaller than the HITRAN intensity cut off. Line profile parameters are added to the line list which is provided in HITRAN format. The comparison of the acetylene database to the HITRAN2012 line list or to results obtained using the global effective operator approach is discussed in terms of completeness and accuracy.

  18. {sup 77} Se NMR of deuteride vinyl and acetylene selenides; RMn de {sup 77} Se de selenetos vinilicos e acetilenicos deuterados

    Energy Technology Data Exchange (ETDEWEB)

    Roque, L C; Stefani, H A; Arruda Campos, I.P. de; Comasseto, J V [Sao Paulo Univ., SP (Brazil). Inst. de Quimica

    1992-12-31

    The main objective of this work is a contribution for establishing a data base sufficient for interpretation of the selenium organic compound spectra. Due to the short literature on acetylene and vinyl selenides, the investigation of these compounds using {sup 77} Se NMR has been considered interesting. Particularly, compounds containing the selenium phenyl group have been selected, as they are larger used in organic chemistry. Non usual deuterated compounds have been applied, viewing simplification of the experimental results interpretation, since the use of deuterium virtually eliminates the Se-H coupling constants, due to the protons of the selenium phenyl group 5 refs., 2 tabs.

  19. Large-scale synthesis of high-purity well-aligned carbon nanotubes using pyrolysis of iron(II) phthalocyanine and acetylene

    Science.gov (United States)

    Liu, B. C.; Lee, T. J.; Lee, S. H.; Park, C. Y.; Lee, C. J.

    2003-08-01

    Well-aligned carbon nanotubes (CNTs) with high purity have been produced by pyrolysis of iron(II) phthalocyanine and acetylene at 800 °C. The synthesized CNTs have a length of 75 μm and diameters ranging from 20 to 60 nm. The CNTs have a bamboo-like structure and exhibit good crystallinity of graphite sheets. The growth rate of the CNTs was rapidly increased with adding C 2H 2. Our results demonstrate that the proposed growth method is suitable to large-scale synthesis of high-purity well-aligned CNTs on various substrates.

  20. Mechanism for the Coupled Photochemistry of Ammonia and Acetylene: Implications for Giant Planets, Comets and Interstellar Organic Synthesis

    Science.gov (United States)

    Keane, Thomas C.

    2017-09-01

    Laboratory studies provide a fundamental understanding of photochemical processes in planetary atmospheres. Photochemical reactions taking place on giant planets like Jupiter and possibly comets and the interstellar medium are the subject of this research. Reaction pathways are proposed for the coupled photochemistry of NH3 (ammonia) and C2H2 (acetylene) within the context Jupiter's atmosphere. We then extend the discussion to the Great Red Spot, Extra-Solar Giant Planets, Comets and Interstellar Organic Synthesis. Reaction rates in the form of quantum yields were measured for the decomposition of reactants and the formation of products and stable intermediates: HCN (hydrogen cyanide), CH3CN (acetonitrile), CH3CH = N-N = CHCH3 (acetaldazine), CH3CH = N-NH2 (acetaldehyde hydrazone), C2H5NH2 (ethylamine), CH3NH2 (methylamine) and C2H4 (ethene) in the photolysis of NH3/C2H2 mixtures. Some of these compounds, formed in our investigation of pathways for HCN synthesis, were not encountered previously in observational, theoretical or laboratory photochemical studies. The quantum yields obtained allowed for the formulation of a reaction mechanism that attempts to explain the observed results under varying experimental conditions. In general, the results of this work are consistent with the initial observations of Ferris and Ishikawa (1988). However, their proposed reaction pathway which centers on the photolysis of CH3CH = N-N = CHCH3 does not explain all of the results obtained in this study. The formation of CH3CH = N-N = CHCH3 by a radical combination reaction of CH3CH = N• was shown in this work to be inconsistent with other experiments where the CH3CH = N• radical is thought to form but where no CH3CH = N-N = CHCH3 was detected. The importance of the role of H atom abstraction reactions was demonstrated and an alternative pathway for CH3CH = N-N = CHCH3 formation involving nucleophilic reaction between N2H4 and CH3CH = NH is advanced.

  1. Acetylene C2H 2 retrievals from MIPAS data and regions of enhanced upper tropospheric concentrations in August 2003

    Directory of Open Access Journals (Sweden)

    V. P. Kanawade

    2011-10-01

    Full Text Available Acetylene (C2H2 volume mixing ratios (VMRs have been successfully retrieved from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS Level 1B radiances during August 2003, providing the first global map of such data and ratios to CO in the literature. The data presented here contain most information between 300 hPa and 100 hPa with systematic errors less than 10% at the upper levels. Random errors per point are less than 15% at lower levels and are closer to 30% at 100 hPa. Global distributions of the C2H2 and C2H2/CO ratio confirm significant features associated with both the Asian monsoon anticyclone and biomass burning for this important hydrocarbon in a characteristic summer month (August 2003, showing tight correlations regionally, particularly at lower to medium values, but globally emphasising the differences between sources and lifetimes of CO and C2H2. The correlations are seen to be particularly disturbed in the regions of highest C2H2 concentrations, indicating variability in the surface emissions or fast processing. A strong isolation of C2H2 within the Asian monsoon anticyclone is observed, evidencing convective transport into the upper troposphere, horizontal advection within the anticyclone at 200 hPa, distinct gradients at the westward edge of the vortex and formation of a secondary dynamical feature from the eastward extension of the anticyclone outflow over the Asian Pacific. Ratios of C2H2/CO are consistent with the evidence from the cross-sections that the C2H2 is uplifted rapidly in convection. Observations are presented of enhanced C2H2 associated with the injection from biomass burning into the upper troposphere and the outflow from Africa at 200 hPa into both the Atlantic and Indian Oceans. In the biomass burning regions, C2H2 and CO are well correlated, but the uplift is less marked and peaks at lower altitudes compared to the strong effects observed in the Asian monsoon anticyclone. Ratios of C2H2/CO

  2. Mechanism for the Coupled Photochemistry of Ammonia and Acetylene: Implications for Giant Planets, Comets and Interstellar Organic Synthesis.

    Science.gov (United States)

    Keane, Thomas C

    2017-09-01

    Laboratory studies provide a fundamental understanding of photochemical processes in planetary atmospheres. Photochemical reactions taking place on giant planets like Jupiter and possibly comets and the interstellar medium are the subject of this research. Reaction pathways are proposed for the coupled photochemistry of NH 3 (ammonia) and C 2 H 2 (acetylene) within the context Jupiter's atmosphere. We then extend the discussion to the Great Red Spot, Extra-Solar Giant Planets, Comets and Interstellar Organic Synthesis. Reaction rates in the form of quantum yields were measured for the decomposition of reactants and the formation of products and stable intermediates: HCN (hydrogen cyanide), CH 3 CN (acetonitrile), CH 3 CH = N-N = CHCH 3 (acetaldazine), CH 3 CH = N-NH 2 (acetaldehyde hydrazone), C 2 H 5 NH 2 (ethylamine), CH 3 NH 2 (methylamine) and C 2 H 4 (ethene) in the photolysis of NH 3 /C 2 H 2 mixtures. Some of these compounds, formed in our investigation of pathways for HCN synthesis, were not encountered previously in observational, theoretical or laboratory photochemical studies. The quantum yields obtained allowed for the formulation of a reaction mechanism that attempts to explain the observed results under varying experimental conditions. In general, the results of this work are consistent with the initial observations of Ferris and Ishikawa (1988). However, their proposed reaction pathway which centers on the photolysis of CH 3 CH = N-N = CHCH 3 does not explain all of the results obtained in this study. The formation of CH 3 CH = N-N = CHCH 3 by a radical combination reaction of CH 3 CH = N• was shown in this work to be inconsistent with other experiments where the CH 3 CH = N• radical is thought to form but where no CH 3 CH = N-N = CHCH 3 was detected. The importance of the role of H atom abstraction reactions was demonstrated and an alternative pathway for CH 3 CH = N-N = CHCH 3 formation involving nucleophilic reaction

  3. Rate Constants and H-Atom Product Yields for the Reactions of O(1D) Atoms with Ethane and Acetylene from 50 to 296 K.

    Science.gov (United States)

    Nunez-Reyes, Dianailys; Hickson, Kevin M

    2018-05-01

    The gas phase reactions of atomic oxygen in its first excited state with ethane and acetylene have been investigated in a continuous supersonic flow reactor over the temperature range 50 K to 296 K. O(1D) atoms were produced by pulsed laser photolysis of ozone at 266 nm. Two different types of experiments, kinetics measurements and H-atom product yield determinations, were performed by detecting O(1D) atoms and H(2S) atoms respectively by vacuum ultraviolet laser induced fluorescence. The measured rate constants are in agreement with previous work at room temperature and little or no temperature dependence was observed as the temperature is decreased to 50 K. H-atoms yields were found to be independent of temperature for the reaction of O(1D) with ethane. These product yields are discussed in the context of earlier dynamics measurements at higher temperature. Due to the influence of secondary reactions, no H-atom yields could be obtained for the reaction of O(1D) with acetylene.

  4. Hydrogen Abstraction Acetylene Addition and Diels-Alder Mechanisms of PAH Formation:  A Detailed Study Using First Principles Calculations.

    Science.gov (United States)

    Kislov, V V; Islamova, N I; Kolker, A M; Lin, S H; Mebel, A M

    2005-09-01

    Extensive ab initio Gaussian-3-type calculations of potential energy surfaces (PES), which are expected to be accurate within 1-2 kcal/mol, combined with statistical theory calculations of reaction rate constants have been applied to study various possible pathways in the hydrogen abstraction acetylene addition (HACA) mechanism of naphthalene and acenaphthalene formation as well as Diels-Alder pathways to acenaphthalene, phenanthrene, and pyrene. The barrier heights; reaction energies; and molecular parameters of the reactants, products, intermediates, and transition states have been generated for all types of reactions involved in the HACA and Diels-Alder mechanisms, including H abstraction from various aromatic intermediates, acetylene addition to radical sites, ring closures leading to the formation of additional aromatic rings, elimination of hydrogen atoms, H disproportionation, C2H2 cycloaddition, and H2 loss. The reactions participating in various HACA sequences (e.g., Frenklach's, alternative Frenklach's, and Bittner and Howard's routes) are demonstrated to have relatively low barriers and high rate constants under combustion conditions. A comparison of the significance of different HACA mechanisms in PAH growth can be made in the future using PES and molecular parameters obtained in the present work. The results show that the Diels-Alder mechanism cannot compete with the HACA pathways even at high combustion temperatures, because of high barriers and consequently low reaction rate constants. The calculated energetic parameters and rate constants have been compared with experimental and theoretical data available in the literature.

  5. Simultaneous detection of Ponceat 4R and tartrazine in food using adsorptive stripping voltammetry on an acetylene black nanoparticle-modified electrode.

    Science.gov (United States)

    Yang, Xiaofeng; Qin, Haibin; Gao, Miaomiao; Zhang, Huajie

    2011-12-01

    Ponceau 4R and tartrazine have been widely used in foodstuffs. However, they are pathogenic if they are excessively consumed. Therefore, the detection of Ponceat 4R and tartrazine is quite important. A sensitive and rapid electrochemical method was developed for the simultaneous detection of Ponceat 4R and tartrazine using anodic adsorptive stripping voltammetry and based on the strong enhancement effect of acetylene black nanoparticle. For Ponceat 4R, the linear range was from 0.05 to 4 mg kg(-1) , and the limit of detection was 0.03 mg kg(-1) . For tartrazine, the linear range was from 0.15 to 18 mg kg(-1) , and the limit of detection was 0.1 mg kg(-1) . The relative standard deviation was 3.8% and 4.7% for 10 successive measurements of 1 mg kg(-1) Ponceau 4R and tartrazine. The method was used to determine Ponceat 4R and tartrazine in soft drinks, and recovery was in the range of 92.4-104.8%. At the acetylene black nanoparticle-modified electrode, the oxidation current signal of Ponceau 4R and tartrazine greatly increase. This new method is sensitive, rapid, simple and feasible. Copyright © 2011 Society of Chemical Industry.

  6. Stable Carbon Isotope Fractionation during Bacterial Acetylene Fermentation: Potential for Life Detection in Hydrocarbon-Rich Volatiles of Icy Planet(oid)s.

    Science.gov (United States)

    Miller, Laurence G; Baesman, Shaun M; Oremland, Ronald S

    2015-11-01

    We report the first study of stable carbon isotope fractionation during microbial fermentation of acetylene (C2H2) in sediments, sediment enrichments, and bacterial cultures. Kinetic isotope effects (KIEs) averaged 3.7 ± 0.5‰ for slurries prepared with sediment collected at an intertidal mudflat in San Francisco Bay and 2.7 ± 0.2‰ for a pure culture of Pelobacter sp. isolated from these sediments. A similar KIE of 1.8 ± 0.7‰ was obtained for methanogenic enrichments derived from sediment collected at freshwater Searsville Lake, California. However, C2H2 uptake by a highly enriched mixed culture (strain SV7) obtained from Searsville Lake sediments resulted in a larger KIE of 9.0 ± 0.7‰. These are modest KIEs when compared with fractionation observed during oxidation of C1 compounds such as methane and methyl halides but are comparable to results obtained with other C2 compounds. These observations may be useful in distinguishing biologically active processes operating at distant locales in the Solar System where C2H2 is present. These locales include the surface of Saturn's largest moon Titan and the vaporous water- and hydrocarbon-rich jets emanating from Enceladus. Acetylene-Fermentation-Isotope fractionation-Enceladus-Life detection.

  7. Acetylene Black/Sulfur Composites Synthesized by a Solution Evaporation Concentration Crystallization Method and Their Electrochemical Properties for Li/S Batteries

    Directory of Open Access Journals (Sweden)

    Zhigao Yang

    2013-07-01

    Full Text Available A novel technique to prepare carbon/sulfur composites as cathode materials for Li/S batteries is proposed, which we call the ‘solution evaporation concentration crystallization’ method. Three composites with different S loadings were prepared, subject to two different solvent evaporation rates from acetylene black (AB/sulfur in carbon disulfide solutions. X-ray diffraction, environmental scanning electron microscopy, transmission electron microscopy, and Brunauer-Emmett-Teller measurements all show that the porous AB structure is well-filled with S. Composites prepared at a lower solvent evaporation rate with 50 wt % S content, had good electrochemical properties, with 1609.67 mAh g−1 after 100 cycles. Composites with better dispersibility at a low solvent evaporation rate can effectively prevent polysulfide from dissolving in the electrolyte, and serve to stabilize the structure of the S cathode during the charge-discharge process.

  8. 'Clicking' on the nanoscale: 1,3-dipolar cycloaddition of terminal acetylenes on azide functionalized, nanometric surface templates with nanometer resolution

    International Nuclear Information System (INIS)

    Haensch, Claudia; Hoeppener, Stephanie; Schubert, Ulrich S

    2009-01-01

    Electro-oxidative lithography is used as a tool to create chemical nanostructures on an n-octadecyltrichlorosilane (OTS) monolayer self-assembled on silicon. The use of a bromine precursor molecule, which is exclusively assembled on these chemical templates, can be used to further functionalize the nanostructures by the site-selective generation of azide functions and performing the highly effective 1,3-dipolar cycloaddition reaction with acetylene functionalized molecules. The versatility of this reaction scheme provides the potential to integrate a large variety of functional molecules, to tailor the surface properties of the nanostructures or to anchor molecular building blocks or particles in confined, pre-defined surface areas. The results demonstrated in the present study introduce a conceivable route towards the functionalization of chemically active surface templates with high fidelity and reliability. It is demonstrated that surface features with a lateral resolution of 50 nm functionalized with propargyl alcohol can be fabricated.

  9. Comparative study of the monomer grafting: ethylene, acetylene, 1,3-butadiene and estyrene in the matrix of recycled polytetrafluoroethylene (PTFE)

    International Nuclear Information System (INIS)

    Ikari, Carolina T.; Rosner, Gerhardyne O.; Oliveira, Ana C.F.; Ferreto, Helio F.R.; Lima, Luiz F.C.P.; Lugao, Ademar B.; Moreira, Otavio M.

    2009-01-01

    In this study it is used the recycled polytetrafluoroethylene (PTFE), that with the gamma radiation under inert atmosphere or in presence of air, it is obtained free radicals and a posterior the monomer grafting (ethylene, acetylene, styrene or 1.3 butadiene), obtaining the copolymer polytetrafluoroethylene-g-monomer. It is studied the obtention of the polymer by two methods: by direct way, via grafting, where the polymer is irradiated in presence of monomer, and via grafting when the polymer is irradiated in absence of monomer and under inert or air. The characterization of the copolymer was performed by the techniques of infrared region absorption spectroscopy with Fourier transformation (FTIR), thermogravimetric (TGA) and derivative thermogravimetry (DTG), and percentage of mass grafting (DOG)

  10. Transition dipole-moment of the ν1 +ν3 band of acetylene measured with dual-comb Fourier-transform spectroscopy

    Science.gov (United States)

    Okubo, Sho; Iwakuni, Kana; Yamada, Koichi M. T.; Inaba, Hajime; Onae, Atsushi; Hong, Feng-Lei; Sasada, Hiroyuki

    2017-11-01

    The ν1 +ν3 vibration band of acetylene (C2H2) in the near infrared region was recorded with a dual-comb Fourier-transform spectrometer. We observed 56 transitions from P (26) to R (29) at six different column densities. The integral line intensity was determined for each recorded absorption line by fitting the line profile to Lambert-Beer's law with a Voigt function. Thanks to the outstanding capability of dual-comb spectroscopy to cover a broad spectrum in a relatively short time with high resolution and high frequency precision, we determined the reliable line strength for each ro-vibrational transition as well as the transition dipole moment for this band.

  11. Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units

    KAUST Repository

    Yao, Zizhu; Zhang, Zhangjing; Liu, Lizhen; Li, Ziyin; Zhou, Wei; Zhao, Yunfeng; Han, Yu; Chen, Banglin; Krishna, Rajamani; Xiang, Shengchang

    2016-01-01

    Acetylene separation is a very important but challenging industrial separation task. Here, through the solvothermal reaction of CuI and 5-triazole isophthalic acid in different solvents, two metal-organic frameworks (MOFs, FJU-21 and FJU-22) with open O donor sites and controllable robustness have been obtained for acetylene separation. They contain the same paddle-wheel {Cu2(COO2)4} nodes and metal-ligand connection modes, but with different helical chains as secondary building units (SBUs), leading to different structural robustness for the MOFs. FJU-21 and FJU-22 are the first examples in which the MOFs' robustness is controlled by adjusting the helical chain SBUs. Good robustness gives the activated FJU-22 a, which has higher surface area and gas uptakes than the flexible FJU-21 a. Importantly, FJU-22 a shows extraordinary separation of acetylene mixtures under ambient conditions. The separation capacity of FJU-22 a for 50:50 C2H2/CO2 mixtures is about twice that of the high-capacity HOF-3, and its actual separation selectivity for C2H2/C2H4 mixtures containing 1 % acetylene is the highest among reported porous materials. Based on first-principles calculations, the extraordinary separation performance of C2H2 for FJU-22 a was attributed to hydrogen-bonding interactions between the C2H2 molecules with the open O donors on the wall, which provide better recognition ability for C2H2 than other functional sites, including open metal sites and amino groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Extraordinary Separation of Acetylene-Containing Mixtures with Microporous Metal-Organic Frameworks with Open O Donor Sites and Tunable Robustness through Control of the Helical Chain Secondary Building Units

    KAUST Repository

    Yao, Zizhu

    2016-03-02

    Acetylene separation is a very important but challenging industrial separation task. Here, through the solvothermal reaction of CuI and 5-triazole isophthalic acid in different solvents, two metal-organic frameworks (MOFs, FJU-21 and FJU-22) with open O donor sites and controllable robustness have been obtained for acetylene separation. They contain the same paddle-wheel {Cu2(COO2)4} nodes and metal-ligand connection modes, but with different helical chains as secondary building units (SBUs), leading to different structural robustness for the MOFs. FJU-21 and FJU-22 are the first examples in which the MOFs\\' robustness is controlled by adjusting the helical chain SBUs. Good robustness gives the activated FJU-22 a, which has higher surface area and gas uptakes than the flexible FJU-21 a. Importantly, FJU-22 a shows extraordinary separation of acetylene mixtures under ambient conditions. The separation capacity of FJU-22 a for 50:50 C2H2/CO2 mixtures is about twice that of the high-capacity HOF-3, and its actual separation selectivity for C2H2/C2H4 mixtures containing 1 % acetylene is the highest among reported porous materials. Based on first-principles calculations, the extraordinary separation performance of C2H2 for FJU-22 a was attributed to hydrogen-bonding interactions between the C2H2 molecules with the open O donors on the wall, which provide better recognition ability for C2H2 than other functional sites, including open metal sites and amino groups. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. An enhanced sensitivity towards H2O2 reduction based on a novel Cu metal–organic framework and acetylene black modified electrode

    International Nuclear Information System (INIS)

    Meng, Wei; Xu, Shuang; Dai, Lei; Li, Yuehua; Zhu, Jing; Wang, Ling

    2017-01-01

    Highlights: • A novel Cu metal–organic framework (Cu-MOF) has been synthesized under hydrothermal condition. • The Cu-MOF modified electrode shows good electrocatalytic activity towards H 2 O 2 reduction in alkaline solution. • The addition of acetylene black improves the response performance of the modified electrode towards H 2 O 2 reduction. - Abstract: As a large class of highly crystalline hybrid materials, metal-organic frameworks (MOFs) have the potentials to act as electrochemical sensors due to their active metal sites and diverse structures. However, the poor electron-conductive property limits their application as electrocatalyst. An effective strategy is to introduce conductive phases to the MOFs. In this paper, a novel Cu metal–organic framework {[Cu 2 (bep)(ada) 2 ]·H 2 O} n (Cu-MOF) (beb = 1,4-bis(2-ethylbenzimidazol-1-ylmethyl) benzene, H 2 ada = 1,3-adamantanediacetic acid) was synthesized under hydrothermal condition. Single-crystal X-ray analysis revealed that the Cu-MOF was a three-dimensional pillar-layered framework with two kinds of paddle-wheel secondary building units. Subsequently, the Cu-MOF modified glassy carbon electrode (GCE) was applied in the H 2 O 2 detection in alkaline solution, and it exhibited the good electrocatalytic activity towards H 2 O 2 reduction. When acetylene black (AB) was added to the Cu-MOF, the electrocatalytic performance of the Cu-MOF modified electrode was greatly improved. The results of amperometric response to H 2 O 2 with different AB addition showed that the Cu-MOF/AB-2%/GCE exhibited a wide linear relationship in the H 2 O 2 concentration range of 0.05–3 μM with a rather high sensitivity of 5.56 μA μM −1 cm −2 , a low detection limit of 0.014 μM as well as a fast response time of 4 s. The Cu-MOF/AB-2%/GCE also exhibited the good selectivity towards H 2 O 2 reduction, and had no response to its normal co-existences of glucose, glycerin, alcohol and lactose. In addition, the modified

  14. Carbon Domains on MoS2/TiO2 System via Catalytic Acetylene Oligomerization: Synthesis, Structure, and Surface Properties

    Directory of Open Access Journals (Sweden)

    Sara Cravanzola

    2017-11-01

    Full Text Available Carbon domains have been obtained at the surface of a MoS2/TiO2 (Evonik, P25 system via oligomerization and cyclotrimerization reactions involved in the interaction of the photoactive material with acetylene. Firstly, MoS2 nanosheets have been synthesized at the surface of TiO2, via sulfidation of a molybdenum oxide precursor with H2S (bottom-up method. Secondly, the morphology and the structure, the optical and the vibrational properties of the obtained materials, for each step of the synthesis procedure, have been investigated by microscopy and spectroscopy methods. In particular, transmission electron microscopy images provide a simple tool to highlight the effectiveness of the sulfidation process, thus showing 1L, 2L, and stacked MoS2 nanosheets anchored to the surface of TiO2 nanoparticles. Lastly, in-situ FTIR spectroscopy investigation gives insights into the nature of the oligomerized species, showing that the formation of both polyenic and aromatic systems can be taken into account, being their formation promoted by both Ti and Mo catalytic sites. This finding gives an opportunity for the assembly of extended polyenic, polyaromatic, or mixed domains firmly attached at the surface of photoactive materials. The presented approach, somehow different from the carbon adding or doping processes of TiO2, is of potential interest for the advanced green chemistry and energy conversion/transport applications.

  15. Electrochemical behavior and voltammetric determination of vanillin based on an acetylene black paste electrode modified with graphene-polyvinylpyrrolidone composite film.

    Science.gov (United States)

    Deng, Peihong; Xu, Zhifeng; Zeng, Rongying; Ding, Chunxia

    2015-08-01

    The graphene-polyvinylpyrrolidone composite film modified acetylene black paste electrode (GR-PVP/ABPE) was fabricated and used to determine vanillin. In 0.1M H3PO4 solution, the oxidation peak current of vanillin increased significantly at GR-PVP/ABPE compared with bare ABPE, PVP/ABPE and GR/ABPE. The oxidation mechanism was discussed. The experimental conditions that exert influence on the voltammetric determination of vanillin, such as supporting electrolytes, pH values, accumulation potential and accumulation time, were optimized. Besides, the interference, repeatability, reproducibility and stability measurements were also evaluated. Under the optimal experimental conditions, the oxidation peak current was proportional to vanillin concentration in the range of 0.02-2.0 μM, 2.0-40 μM and 40-100 μM. The detection limit was 10nM. This sensor was used successfully for vanillin determination in various food samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. Improvements of anti-corrosion and mechanical properties of NiTi orthopedic materials by acetylene, nitrogen and oxygen plasma immersion ion implantation

    International Nuclear Information System (INIS)

    Poon, Ray W.Y.; Ho, Joan P.Y.; Liu Xuanyong; Chung, C.Y.; Chu, Paul K.; Yeung, Kelvin W.K.; Lu, William W.; Cheung, Kenneth M.C.

    2005-01-01

    Nickel-titanium shape memory alloys (NiTi) are useful materials in orthopedics and orthodontics due to their unique super-elasticity and shape memory effects. However, the problem associated with the release of harmful Ni ions to human tissues and fluids has been raising safety concern. Hence, it is necessary to produce a surface barrier to impede the out-diffusion of Ni ions from the materials. We have conducted acetylene, nitrogen and oxygen plasma immersion ion implantation (PIII) into NiTi alloys in an attempt to improve the surface properties. All the implanted and annealed samples surfaces exhibit outstanding corrosion and Ni out-diffusion resistance. Besides, the implanted layers are mechanically stronger than the substrate underneath. XPS analyses disclose that the layer formed by C 2 H 2 PIII is composed of mainly TiC x with increasing Ti to C concentration ratios towards the bulk. The nitrogen PIII layer is observed to be TiN, whereas the oxygen PIII layer is composed of oxides of Ti 4+ , Ti 3+ and Ti 2+

  17. Improving the Working Efficiency of a Triboelectric Nanogenerator by the Semimetallic PEDOT:PSS Hole Transport Layer and Its Application in Self-Powered Active Acetylene Gas Sensing.

    Science.gov (United States)

    Uddin, A S M Iftekhar; Yaqoob, Usman; Chung, Gwiy-Sang

    2016-11-09

    Herein we report an enhanced triboelectric nanogenerator (TENG) based on the contact-separation mode between a patterned film of polydimethylsiloxane (PDMS) with a semimetallic elastomer of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and a nylon fiber film. The addition of ethylene glycol to the PEDOT:PSS film improves the functionality of the TENG significantly, yielding promising applicability in both indoor and outdoor (i.e., under sunlight) environments, with the maximum instantaneous power of 0.09 mW (indoors) and 0.2 mW (outdoors) for the load resistance of 3.8 MΩ. The device can also generate 11.2 V and 0.08 μA cm -2 in response to the forearm movement of a human. Additionally, by replacing the bare nylon fiber in the TENG design with a Ag@ZnO/nylon fiber film, a self-powered active sensor (triboelectric nanogenerator-based sensor; TENS) has been realized to detect acetylene (C 2 H 2 ) gas. The TENS exhibits excellent sensitivity of 70.9% (indoors) and 89% (outdoors) to C 2 H 2 gas of 1000 ppm concentration. The proposed approach for harvesting energy and sensing can be advantageous in practical applications and may stimulate new research that will enhance nanogenerators as well as wearable, self-powered active sensors.

  18. Effect of Fe2O3 and Binder on the Electrochemical Properties of Fe2O3/AB (Acetylene Black) Composite Electrodes

    Science.gov (United States)

    Anh, Trinh Tuan; Thuan, Vu Manh; Thang, Doan Ha; Hang, Bui Thi

    2017-06-01

    In an effort to find the best anode material for Fe/air batteries, a Fe2O3/AB (Acetylene Black) composite was prepared by dry-type ball milling using Fe2O3 nanoparticles and AB as the active and additive materials, respectively. The effects of various binders and Fe2O3 content on the electrochemical properties of Fe2O3/AB electrodes in alkaline solution were investigated. It was found that the content of Fe2O3 strongly affected the electrochemical behavior of Fe2O3/AB electrodes; with Fe2O3 nanopowder content reaching 70 wt.% for the electrode and showing improvement of the cyclability. When the electrode binder polytetrafluoroethylene (PTFE) was used, clear redox peaks were observed via cyclic voltammetry (CV), while polyvinylidene fluoride-containing electrodes provided CV curves with unobservable redox peaks. Increasing either binder content in the electrode showed a negative effect in terms of the cyclability of the Fe2O3/AB electrode.

  19. Simultaneous voltammetric determination of 2-nitrophenol and 4-nitrophenol based on an acetylene black paste electrode modified with a graphene-chitosan composite

    International Nuclear Information System (INIS)

    Deng, Peihong; Xu, Zhifeng; Li, Junhua

    2014-01-01

    We describe a simple and sensitive voltammetric method for the simultaneous determination of 2-nitrophenol and 4-nitrophenol. It is based on the use of an acetylene black paste electrode modified with a graphene-chitosan composite film (denoted as Gr-Chit/ABPE). The reduction peak currents of 2-nitrophenol (at −252 mV) and of 4-nitrophenol (at −340 mV) in pH 1.0 solution increase significantly at the Gr-Chit/ABPE in comparison to a bare ABPE. Factors affecting sensitivity were optimized and a linear relationship is found between peak current and the concentrations of 2-nitrophenol (in the 0.4 μM to 80 μM range) and for 4-nitrophenol (in the 0.1 μM to 80 μM range). The detection limits (at an SNR of 3 and after a 30-s accumulation time) are 200 nM for 2-nitrophenol and 80 nM for 4-nitrophenol, respectively. The modified electrode was successfully applied to the direct and parallel determination of 2-nitrophenol and 4-nitrophenol in spiked water samples. (author)

  20. Acetylene Black Induced Heterogeneous Growth of Macroporous CoV2O6 Nanosheet for High-Rate Pseudocapacitive Lithium-Ion Battery Anode.

    Science.gov (United States)

    Zhang, Lei; Zhao, Kangning; Luo, Yanzhu; Dong, Yifan; Xu, Wangwang; Yan, Mengyu; Ren, Wenhao; Zhou, Liang; Qu, Longbing; Mai, Liqiang

    2016-03-23

    Metal vanadates suffer from fast capacity fading in lithium-ion batteries especially at a high rate. Pseudocapacitance, which is associated with surface or near-surface redox reactions, can provide fast charge/discharge capacity free from diffusion-controlled intercalation processes and is able to address the above issue. In this work, we report the synthesis of macroporous CoV2O6 nanosheets through a facile one-pot method via acetylene black induced heterogeneous growth. When applied as lithium-ion battery anode, the macroporous CoV2O6 nanosheets show typical features of pseudocapacitive behavior: (1) currents that are mostly linearly dependent on sweep rate and (2) redox peaks whose potentials do not shift significantly with sweep rate. The macroporous CoV2O6 nanosheets display a high reversible capacity of 702 mAh g(-1) at 200 mA g(-1), excellent cyclability with a capacity retention of 89% (against the second cycle) after 500 cycles at 500 mA g(-1), and high rate capability of 453 mAh g(-1) at 5000 mA g(-1). We believe that the introduction of pseudocapacitive properties in lithium battery is a promising direction for developing electrode materials with high-rate capability.

  1. Radiation Polymerization of Acetylene Hydrocarbons. Special Features; Particularites de la polymerisation radiochimique des hydrocarbures acetyleniques; Radiatsionnaya polimerizatsiya atsetilenovykh proizvodnykh; Particularidades de la radiopolimerizacion de los hidrocarburos acetilenicos

    Energy Technology Data Exchange (ETDEWEB)

    Barkalov, I. M.; Gol' danskij, V. I.; Go, Min' -Gao

    1963-11-15

    The synthesis and study of the properties of polymers with conjugated bond systems offers new and extremely promising prospects in the chemistry of high molecular compounds. A high degree of de-localization of p-electrons in the macromolecule is characteristic of such polymer systems. The decrease in the energy excited in the triplet state, just like the diminished ionization potential with large conjugated bonds, conditions the semiconductor and specific magnetic properties of such compounds. In addition, polymer systems with conjugated bonds have proved to be extremely effective stabilizers in the thermo- and photo-oxidation destruction of polymers. The radiation polymerization of acetylene derivatives offers one suitable method of obtaining such polymers and is the only one which ensures that the polymers obtained are free of contamination from initiators at low temperatures. The kinetics of the radiation polymerization of ethynyl benzene and other acetylene derivatives have a number of features typical of ion polymerization quite rare in radical polymerization (speed of polymerization linearly proportional to speed of initiation: very low activation energy; no oxygen inhibition). Nevertheless this polymerization is obviously radical. We reached that conclusion on the basis of a study of polymerization initiation for acetylene hydrocarbons by typical radical initiators - benzoyl peroxide and the dinitrile of azoisobutyric acid. They investigated the kinetic features and mechanism of peroxide decomposition in the presence of acetylene hydrocarbons (e.g. ethynyl benzene, deutero-ethynyl benzene and phenylpropyne). The kinetics of radiation co-polymerization of ethynyl benzene with different vinyl monomers and the composition of copolymers in different initial mixtures were also studied. These data and the results of a study of the kinetics of inhibited ethynyl benzene polymerization (benzoquinone initiator) indicate a small reactivity capacity of the ethynyl

  2. Effect of Acetylene Black Content in Li4Ti5O12 Xerogel Solid-State Anode Materials on Half-Cell Li-ion Batteries Performance

    Science.gov (United States)

    Abdurrahman, N. M.; Priyono, B.; Syahrial, A. Z.; Subhan, A.

    2017-07-01

    The effect of Acetylene Black (AB) additive contents in lithium titanate/Li4Ti5O12 (LTO) anode on Li-ion Batteries performance is studied in this work. The LTO active material for Li-ion batteries anode was successfully synthesized using sol-gel method to form TiO2 xerogel continued by mixing process with LiOH in ball-mill and then sintered to obtain spinel LTO. The LTO powder is characterized by X-Ray Diffraction (XRD), scanning electron microscopy-Energy Dispersive Spectroscopy (SEM-EDS), and Brunauer-Emmett-Teller (BET). The spinel LTO and TiO2 rutile were detected by XRD diffractogram. The LTO powder is in the form of agglomerates structure. This powder then was mixed with PVDF binder (10%wt) and AB additives with various amount from 10%wt (LTO2 Ac-1), 12%wt (LTO2 Ac-2), and 15%wt (LTO2 Ac-3) of total weight solid content to form electrode sheet. Half-cell coin battery was made with lithium metal foil as a counter electrode. Cyclic voltammetry (CV), Electrochemical-impedance spectroscopy (EIS), and charge discharge (CD) test used to examine the battery performance. The highest resistance value is obtained in LTO2 Ac-3 sample with 15%wt of AB. It might be caused by the formation of side reaction product on electrode surface at initial cycle due to high reactivity of LTO2 Ac-3 electrode. The highest initial capacity at CV test and CD test was obtained in LTO2 Ac-1 (10%wt AB) sample, due to the best proportion of active material content in the compound. While, in the charge-discharge test at high current rate, the best sample rate-capability performance belongs to LTO2 Ac-3 sample (15%wt AB), which still have 24.12 mAh/g of discharge capacity at 10 C with 71.34% capacity loss.

  3. Secondary Organic Aerosol Formation from Acetylene (C2H2: seed effect on SOA yields due to organic photochemistry in the aerosol aqueous phase

    Directory of Open Access Journals (Sweden)

    P. J. Ziemann

    2009-03-01

    Full Text Available The lightest Non Methane HydroCarbon (NMHC, i.e., acetylene (C2H2 is found to form secondary organic aerosol (SOA. Contrary to current belief, the number of carbon atoms, n, for a NMHC to act as SOA precursor is lowered to n=2 here. The OH-radical initiated oxidation of C2H2 forms glyoxal (CHOCHO as the highest yield product, and >99% of the SOA from C2H2 is attributed to CHOCHO. SOA formation from C2H2 and CHOCHO was studied in a photochemical and a dark simulation chamber. Further, the experimental conditions were varied with respect to the chemical composition of the seed aerosols, mild acidification with sulphuric acid (SA, 3

  4. Polymer Soft-Landing Isolation of Acetylene on Polystyrene and Poly(vinylpyridine): A Novel Approach to Probing Hydrogen Bonding in Polymers.

    Science.gov (United States)

    Li, Yike; Samet, Cindy

    2015-09-17

    Hydrogen-bonded complexes of acetylene (Ac) with the polymers polystyrene (PS), poly(4-vinylpyridine) (P4VP), and poly(2-vinylpyridine) (P2VP) have been characterized for the first time at 16 K in a "polymer soft-landing isolation" experiment which is being pioneered in our research laboratory. In particular, changes in vibrational modes of Ac provide ample evidence for hydrogen-bonded complexes between Ac and the phenyl groups of PS or the pyridyl groups of P4VP and P2VP. With PS, the proton on the top Ac molecule of the classic T-shaped Ac dimer interacts with the π cloud of the benzene (Bz) ring to form a C-H---π interaction, while the π cloud of the lower Ac forms a second C-H---π interaction with a proton on the Bz ring. An analogous (ring)1-(Ac)2 double interaction occurs between an Ac dimer and the pyridine (Pyr) rings on both P2VP and P4VP, yielding a C-H---N and C-H---π interaction. With P4VP and P2VP a second bridged (ring)2-(Ac)2 product is formed, with the Ac dimer forming nearly collinear C-H---N hydrogen bonds to adjacent Pyr rings. On P2VP this bridged product is the only one after extensive annealing. These complexes in which Ac acts as both proton donor and acceptor have not previously been observed in conventional matrix isolation experiments. This study is the second from our laboratory employing this method, which represents a slight modification of the traditional matrix isolation technique.

  5. Pharmacokinetics and pharmacodynamics of orally administered acetylenic tricyclic bis(cyanoenone), a highly potent Nrf2 activator with a reversible covalent mode of action

    Energy Technology Data Exchange (ETDEWEB)

    Kostov, Rumen V.; Knatko, Elena V.; McLaughlin, Lesley A.; Henderson, Colin J. [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Zheng, Suqing [Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY, 11794 (United States); Huang, Jeffrey T.-J. [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Honda, Tadashi [Department of Chemistry and Institute of Chemical Biology & Drug Discovery, Stony Brook University, Stony Brook, NY, 11794 (United States); Dinkova-Kostova, Albena T., E-mail: a.dinkovakostova@dundee.ac.uk [Jacqui Wood Cancer Centre, Division of Cancer Research, Medical Research Institute, University of Dundee, Dundee, DD1 9SY, Scotland (United Kingdom); Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, 21205 (United States); Department of Pharmacology and Molecular Sciences, Johns Hopkins University School of Medicine, Baltimore, MD, 21205 (United States)

    2015-09-25

    The acetylenic tricyclic bis(cyanoenone) TBE-31 is a highly potent cysteine targeting compound with a reversible covalent mode of action; its best-characterized target being Kelch-like ECH-associated protein-1 (Keap1), the cellular sensor for oxidants and electrophiles. TBE-31 reacts with cysteines of Keap1, impairing its ability to target nuclear factor-erythroid 2 p45-related factor 2 (Nrf2) for degradation. Consequently, Nrf2 accumulates and orchestrates cytoprotective gene expression. In this study we investigated the pharmacokinetic and pharmacodynamic properties of TBE-31 in C57BL/6 mice. After a single oral dose of 10 μmol/kg (∼200 nmol/animal), the concentration of TBE-31 in blood exhibited two peaks, at 22.3 nM and at 15.5 nM, 40 min and 4 h after dosing, respectively, as determined by a quantitative stable isotope dilution LC-MS/MS method. The AUC{sub 0–24h} was 195.5 h/nmol/l, the terminal elimination half-life was 10.2 h, and the k{sub el} was 0.068 h{sup −1}. To assess the pharmacodynamics of Nrf2 activation by TBE-31, we determined the enzyme activity of its prototypic target, NAD(P)H:quinone oxidoreductase 1 (NQO1) and found it elevated by 2.4- and 1.5-fold in liver and heart, respectively. Continuous feeding for 18 days with diet delivering the same daily doses of TBE-31 under conditions of concurrent treatment with the immunosuppressive agent azathioprine had a similar effect on Nrf2 activation without any indications of toxicity. Together with previous reports showing the cytoprotective effects of TBE-31 in animal models of carcinogenesis, our results demonstrate the high potency, efficacy and suitability for chronic administration of cysteine targeting reversible covalent drugs. - Highlights: • TBE-31 is a cysteine targeting compound with a reversible covalent mode of action. • After a single oral dose, the blood concentration of TBE-31 exhibits two peaks. • Oral TBE-31 is a potent activator of Nrf2-dependent enzymes in

  6. Effect of in situ pyrolysis of acetylene (C2H2) gas as a carbon source on the electrochemical performance of LiFePO4 for rechargeable lithium-ion batteries

    Science.gov (United States)

    Saroha, Rakesh; Panwar, Amrish K.

    2017-06-01

    The intention of this work is to study the effect of in situ pyrolysis of acetylene (C2H2) gas used as a carbon source on the physicochemical and electrochemical performance of pristine LiFePO4 (LFP). Acetylene gas, which decomposed to carbon and methane along with some side products when exposed to high temperature (>625 °C), is used as a carbon source for coating over the surface of LFP particles. Thermogravimetric (TGA) measurements were performed in an air atmosphere, primarily to estimate the exact amount of carbon deposited on the surface of the olivine cathode material due to the decomposition of C2H2 gas. Raman and TGA results confirm the presence of carbon as coated on the surface of the prepared compositions. Among all the synthesized samples, LFP with 10 min C2H2 treatment (LFPC10) shows the highest discharge capacity at all C-rates and exhibits excellent rate performance. LFPC10 delivers a specific discharge capacity of 144 (±5) mAh g-1 (~85% of the theoretical capacity of 170 mAh g-1) at 0.1C rate. LFPC10 demonstrates the best cycling performance as it offers an initial discharge capacity of about 117 (±5) mAh g-1 (~69% of the theoretical capacity) at 1C-rate and has 97% capacity retention even after 100 charge/discharge cycles.

  7. Role of the reaction intermediates in determining PHIP (parahydrogen induced polarization) effect in the hydrogenation of acetylene dicarboxylic acid with the complex [Rh (dppb)]+ (dppb: 1,4-bis(diphenylphosphino)butane)

    International Nuclear Information System (INIS)

    Reineri, F.; Aime, S.; Gobetto, R.; Nervi, C.

    2014-01-01

    This study deals with the parahydrogenation of the symmetric substrate acetylene dicarboxylic acid catalyzed by a Rh(I) complex bearing the chelating diphosphine dppb (1,4-bis(diphenylphosphino)butane). The two magnetically equivalent protons of the product yield a hyperpolarized emission signal in the 1 H-NMR spectrum. Their polarization intensity varies upon changing the reaction solvent from methanol to acetone. A detailed analysis of the hydrogenation pathway is carried out by means of density functional theory calculations to assess the structure of hydrogenation intermediates and their stability in the two solvents. The observed polarization effects have been accounted on the basis of the obtained structures. Insights into the lifetime of a short-lived reaction intermediate are also obtained

  8. Peut-on envisager le remplacement de l'éthylène par l'acétylène à moyen terme ? Can the Substitution of Ethylene by Acetylene Be Imagined in the Medium Term?

    Directory of Open Access Journals (Sweden)

    Lefebvre G.

    2006-11-01

    Full Text Available L'accroissement considérable depuis 1973 du coût des énergies fossiles, notamment du pétrole, a fortement contribué au renchérissement du prix de l'éthylène alors que parallèlement l'acétylène fabriqué au départ de carbure de calcium ou par arc électrique pouvait espérer bénéficier d'un coût relatif plus faible de l'énergie électrique d'origine nucléaire. II ressort de la présente étude que malgré les hypothèses favorables suivantes : - taux de croissance moyen du prix du pétrole à monnaie constante 1982 de 7 % par an, - augmentation de celui du charbon limitée à 3 % par an, - énergie électrique disponible en permanence à 5 et 10 c/kWh, - capacité unitaire de production d'acétylène de l'ordre de 300 000 t/an comparable à celle de l'éthylène, il apparaît impossible que l'acétylène puisse concurrencer l'éthylène avant l'an 2000. Seul le chlorure de vinyle pourrait être fabriqué à partir d'acétylène favorisé par un important facteur d'échelle, à condition que l'électricité puisse être alimentée en permanence à 0,10 F le kWh. Cette constatation ne tient pas compte de la remise en cause des procédés pétrochimiques actuels d'obtention des intermédiaires de seconde génération dont la fabrication à partir d'acétylène nécessiterait la création d'installations de conception entièrement différente. Alors qu'en 1975 les procédés à l'arc électrique de production d'acétylène à partir de naphta apparaissaient plus économiques que la voie carbure de calcium, on constate actuellement une situation inverse, consécutive aux augmentations de prix du pétrole qui ont suivi. The considerable increase in the cost of fossil energy sources since 1973, and especially that of oil, has greatly helped drive up the price of ethylene, whereas at the same time acetylene manufactured initially from calcium carbide or by electric arc could have hoped to profit from the relative low price of electric

  9. Method development for the determination of fluorine in toothpaste via molecular absorption of aluminum mono fluoride using a high-resolution continuum source nitrous oxide/acetylene flame atomic absorption spectrophotometer.

    Science.gov (United States)

    Ozbek, Nil; Akman, Suleyman

    2012-05-30

    Fluorine was determined via the rotational molecular absorption line of aluminum mono fluoride (AlF) generated in C(2)H(2)/N(2)O flame at 227.4613 nm using a high-resolution continuum source flame atomic absorption spectrophotometer (HR-CS-FAAS). The effects of AlF wavelength, burner height, fuel rate (C(2)H(2)/N(2)O) and amount of Al on the accuracy, precision and sensitivity were investigated and optimized. The Al-F absorption band at 227.4613 nm was found to be the most suitable analytical line with respect to sensitivity and spectral interferences. Maximum sensitivity and a good linearity were obtained in acetylene-nitrous oxide flame at a flow rate of 210 L h(-1) and a burner height of 8mm using 3000 mg L(-1) of Al for 10-1000 mg L(-1)of F. The accuracy and precision of the method were tested by analyzing spiked samples and waste water certified reference material. The results were in good agreement with the certified and spiked amounts as well as the precision of several days during this study was satisfactory (RSD<10%). The limit of detection and characteristic concentration of the method were 5.5 mg L(-1) and 72.8 mg L(-1), respectively. Finally, the fluorine concentrations in several toothpaste samples were determined. The results found and given by the producers were not significantly different. The method was simple, fast, accurate and sensitive. Copyright © 2012 Elsevier B.V. All rights reserved.

  10. Superexcited states on ethylene and acetylene

    International Nuclear Information System (INIS)

    Azevedo e Souza, A.C. de; Souza, G.G.B. de

    1988-01-01

    Electron energy loss spectra were obtained for C 2 H 2 and C 2 H 4 in the energy loss range from 12 to 50 eV for 1 Kev electrons. Elastic and inelastic cross sections and generalized oscillator strengths for transitions at 13.3, 15.7 and 18.7 eV were obtained. (A.C.A.S.) [pt

  11. S1 Supplementary information Cycloisomerization of acetylenic ...

    Indian Academy of Sciences (India)

    The outputs were exported to PyMOL Molecular Graphics System,. Version 1.3 Schrödinger for visual inspection of the binding modes and interactions of the compounds with amino acid residues in the active sites. Note: The relevant discussion corresponding to Figure 4, 5 and 6 (see below) was discussed in the section 3.3 ...

  12. Comparative study of the monomer grafting: ethylene, acetylene, 1,3-butadiene and estyrene in the matrix of recycled polytetrafluoroethylene (PTFE); Estudo comparativo da enxertia dos monomeros: etileno, acetileno, 1,3-butadieno e estireno na matriz de politetrafluoroetileno (PTFE) reciclado

    Energy Technology Data Exchange (ETDEWEB)

    Ikari, Carolina T.; Rosner, Gerhardyne O.; Oliveira, Ana C.F. [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente (CQMA); Faculdades Oswaldo Cruz, Sao Paulo, SP (Brazil); Ferreto, Helio F.R.; Lima, Luiz F.C.P.; Lugao, Ademar B., E-mail: hferreto@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil). Centro de Quimica e Meio Ambiente (CQMA); Moreira, Otavio M. [Faculdades Oswaldo Cruz, Sao Paulo, SP (Brazil)

    2009-07-01

    In this study it is used the recycled polytetrafluoroethylene (PTFE), that with the gamma radiation under inert atmosphere or in presence of air, it is obtained free radicals and a posterior the monomer grafting (ethylene, acetylene, styrene or 1.3 butadiene), obtaining the copolymer polytetrafluoroethylene-g-monomer. It is studied the obtention of the polymer by two methods: by direct way, via grafting, where the polymer is irradiated in presence of monomer, and via grafting when the polymer is irradiated in absence of monomer and under inert or air. The characterization of the copolymer was performed by the techniques of infrared region absorption spectroscopy with Fourier transformation (FTIR), thermogravimetric (TGA) and derivative thermogravimetry (DTG), and percentage of mass grafting (DOG)

  13. 46 CFR 154.1735 - Methyl acetylene-propadiene mixture.

    Science.gov (United States)

    2010-10-01

    ... relieve into the compressor suction line. (4) An alarm that sounds in the cargo control station and in the... mixture must have a refrigeration system without vapor compression or have a refrigeration system with the following features: (1) A vapor compressor that does not raise the temperature and pressure of the vapor...

  14. New insights in the low-temperature oxidation of acetylene

    DEFF Research Database (Denmark)

    Wang, Bing-Yin; Liu, Yue-Xi; Weng, Jun-Jie

    2017-01-01

    This work presents new experimental data of C2H2 low-temperature oxidation for equivalence ratios Φ= 0.5–3.0 in a newly designed jet-stirred reactor over a temperature range of 600–1100K at atmospheric pressure with residence time corresponding from 1.94 to 1.06s. Mole fraction profiles of 17...... intermediates including aromatic compounds such as toluene, styrene and ethylbenzene were quantified. A detailed kinetic mechanism involving 295 species and 1830 reactions was established to predict the oxidation of C2H2 and formation of PAH. In developing the mechanism, particular attention was paid...

  15. 76 FR 75840 - Revising Standards Referenced in the Acetylene Standard

    Science.gov (United States)

    2011-12-05

    ... Flexibility Act Certification C. OMB Review Under the Paperwork Reduction Act of 1995 D. Federalism E. State... meaning of Section 652(8) when a significant risk of material harm exists in the workplace and the standard would substantially reduce or eliminate that workplace risk. This NPRM would not reduce the...

  16. 76 FR 75782 - Revising Standards Referenced in the Acetylene Standard

    Science.gov (United States)

    2011-12-05

    ... Determinations A. Legal Considerations B. Final Economic Analysis and Regulatory Flexibility Act Certification C... within the meaning of Section 652(8) when a significant risk of material harm exists in the workplace and the standard would substantially reduce or eliminate that workplace risk. This DFR will not reduce the...

  17. Antimalarial Activity of Acetylenic Thiophenes from Echinops hoehnelii Schweinf

    Directory of Open Access Journals (Sweden)

    Helen Bitew

    2017-11-01

    Full Text Available Malaria is one of the world’s most severe endemic diseases and due to the emergence of resistance to the currently available medicines, the need for new targets and relevant antimalarial drugs remains acute. The crude extract, four solvent fractions and two isolated compounds from the roots of Echinops hoehnelii were tested for their antimalarial activity using the standard four-day suppressive method in Plasmodium berghei-infected mice. The 80% methanol extract exhibited suppression of 4.6%, 27.8%, 68.5% and 78.7% at dose of 50, 100, 200 and 400 mg/kg respectively. The dichloromethane fraction displayed chemosuppression of 24.9, 33.5 and 43.0% dose of 100, 200 and 400 mg/kg of body weight. Five acetylenicthiophenes were isolated from the dichloromethane fraction of which 5-(penta-1,3-diynyl-2-(3,4-dihydroxybut-1-ynyl-thiophene decreased the level of parasitaemia by 43.2% and 50.2% while 5-(penta-1,3-diynyl-2-(3-chloro-4-acetoxy-but-1-yn-thiophene suppressed by 18.8% and 32.7% at 50 and 100 mg/kg, respectively. The study confirmed the traditional claim of the plant to treat malaria and could be used as a new lead for the development of antimalarial drugs.

  18. Donor-Acceptor Chromophores based on Acetylenic Scaffolds and Indenofluorenes

    DEFF Research Database (Denmark)

    Christensen, Mikkel Andreas

    -valence salt). [BILLEDE UDELADT] In the third chapter the reactivity of chloroalkynes is explored. A number of chloroalkynes is prepared and subjected to palladium-catalyzed cross coupling with a terminal alkyne. The chloroalkynes turned out to couple very well using the same conditions as for the Sonogashira...... cross-coupling. The reactivity of chloroalkynes was compared to that of Sonogashira substrates and the chloroalkynes turned out to react as fast as an aryl iodide. Some of the couplings gave reductive homo-coupling of the chloroalkyne as a byproducts. This was avoided by using a large copper...

  19. 77 FR 13997 - Revising Standards Referenced in the Acetylene Standard

    Science.gov (United States)

    2012-03-08

    ...: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Proposed rule; withdrawal. SUMMARY: With this document, OSHA is withdrawing the proposed rule that accompanied its direct-final rule revising... and press inquiries: Contact Frank Meilinger, Director, OSHA Office of Communications, Room N-3647, U...

  20. 75 FR 5707 - Revising Standards Referenced in the Acetylene Standard

    Science.gov (United States)

    2010-02-04

    ...: Occupational Safety and Health Administration (OSHA), Labor. ACTION: Proposed rule; withdrawal. SUMMARY: With this document, OSHA is withdrawing the proposed rule that accompanied its direct-final rule revising... and press inquiries: Contact Jennifer Ashley, Director, OSHA Office of Communications, Room N-3647, U...

  1. Reaction of atomic bromine with acetylene and loss rate of atmospheric acetylene due to reaction with OH, Cl, O, and Br

    Science.gov (United States)

    Payne, W. A.; Nava, D. F.; Brunning, J.; Stief, L. J.

    1986-01-01

    The first-order, diffusion, and bimolecular rate constants for the reaction Br + C2H2 yields C2H3Br are evaluated. The rate constants are measured at 210, 248, 298, and 393 K and at pressures between 15-100 torr Ar using flash photolysis combined with time-resolved detection of atomic bromine via Br resonance radiation. It is observed that the reaction is not affected by pressure or temperature and the bimolecular constant = (4.0 + or - 0.8) x 10 to the -15th cu cm/sec with an error of two standard deviations. The C2H2 + Br reaction rates are compared with reactions of C2H2 with Cl, OH, NH2, and H. The loss rates for atmospheric C2H2 for reactions with OH, Cl, O, and Br are calculated as a function of altitude.

  2. ZnO based nanowires grown by chemical vapour deposition for selective hydrogenation of acetylene alcohols

    NARCIS (Netherlands)

    Protasova, L.N.; Rebrov, E.; Choy, K.L.; Pung, S.Y.; Engels, V.; Cabaj, M.; Wheatley, A.E.H.; Schouten, J.C.

    2011-01-01

    Vertically aligned ZnO nanowires (NWs) with a length of 1.5–10 µm and a mean diameter of ca. 150 nm were grown by chemical vapour deposition onto a c-oriented ZnO seed layer which was deposited by atomic layer deposition on Si substrates. The substrates were then spin-coated with an ethanol solution

  3. TERAHERTZ SPECTROSCOPY AND GLOBAL ANALYSIS OF THE BENDING VIBRATIONS OF ACETYLENE 12C2D2

    International Nuclear Information System (INIS)

    Yu Shanshan; Drouin, Brian J.; Pearson, John C.; Pickett, Herbert M.; Lattanzi, Valerio; Walters, Adam

    2009-01-01

    Two hundred and fifty-one 12 C 2 D 2 transitions have been measured in the 0.2-1.6 THz region of its ν 5 -ν 4 difference band and 202 of them were observed for the first time. The accuracy of these measurements is estimated to be ranging from 50 kHz to 100 kHz. The 12 C 2 D 2 molecules were generated under room temperature by passing 120-150 mTorr D 2 O vapor through calcium carbide (CaC 2 ) powder. A multistate analysis was carried out for the bending vibrational modes ν 4 and ν 5 of 12 C 2 D 2 , which includes the lines observed in this work and prior microwave, far-infrared and infrared data on the pure bending levels. Significantly improved molecular parameters were obtained for 12 C 2 D 2 by adding the new measurements to the old data set, which had only 10 lines with microwave measurement precision. New frequency and intensity predictions have been made based on the obtained molecular parameters. The more precise measurements and new predictions reported here will support the analyses of astronomical observations by the future high-resolution spectroscopy telescopes such as Herschel, SOFIA, and ALMA, which will work in the terahertz spectral region.

  4. Nitrogenase activity (acetylene reduction activity) and diversity of six soil Nostoc strains

    Czech Academy of Sciences Publication Activity Database

    Hrouzek, P.; Šimek, Miloslav; Komárek, Jiří

    2003-01-01

    Roč. 108, - (2003), s. 87-101 ISSN 0342-1120 R&D Projects: GA AV ČR KSK6005114 Institutional research plan: CEZ:AV0Z6066911 Keywords : cyanobacteria * Nostoc * morphology Subject RIV: EH - Ecology, Behaviour

  5. Ultrafast isomerization in acetylene dication after carbon K-shell ionization

    Czech Academy of Sciences Publication Activity Database

    Li, Z.; Inhester, L.; Liekhus-Schmaltz, C.; Curchod, B.F.E.; Snyder Jr., J.W.; Medvedev, Nikita; Cryan, J.P.; Osipov, T.; Pabst, S.; Vendrell, O.; Bucksbaum, P.; Martinez, T.J.

    2017-01-01

    Roč. 8, č. 1 (2017), s. 1-7, č. článku 453. ISSN 2041-1723 R&D Projects: GA MŠk LG15013 Institutional support: RVO:68378271 Keywords : molecular- dynamics * conical intersection * electronic states * ab-initio * vinylidene Subject RIV: BL - Plasma and Gas Discharge Physics OBOR OECD: Fluids and plasma physics (including surface physics) Impact factor: 12.124, year: 2016

  6. Using the Wolfsberg--Schactschneider program to calculate equilibrium constants for isotopic acetylenes

    International Nuclear Information System (INIS)

    Liu, D.K.K.; Pyper, J.W.

    1977-01-01

    Equilibrium constants were calculated for the gas-phase isotopic exchange reactions C 2 H 2 + C 2 D 2 = 2C 2 HD and C 2 H 2 + D 2 O = C 2 D 2 + H 2 O at temperatures ranging from 40 to 2000 0 K. No corrections to the harmonic approximation were made. The results agree quite well with experimental measurements

  7. Pyrolysis of Polyolefins Using Rotating Arc Plasma Technology for Production of Acetylene

    Directory of Open Access Journals (Sweden)

    Ming Zhang

    2017-04-01

    Full Text Available Polyolefin, as one of the most widely used macromolecule materials, has been one of the most serious threats to the environment. Current treatment methods of waste polyolefin including landfill, incineration, and thermal degradation have suffered from severe problems such as secondary pollution and the generation of other toxic substances. In this article, we report for the first time a high-efficiency method to produce high-value C2H2 from polyolefins using a rotating direct current arc plasma reactor, using polyethylene and polypropylene as feedstocks. The essence of this method is that a reductive atmosphere of pyrolysis enables a thermodynamic preference to C2H2 over other carbon-containing gas and the rotating direct current arc plasma reactor allows for a uniform distribution of high temperature to ensure high conversion of polymers. Thermodynamic simulation of product composition was performed, and the effect of plasma input power, polyolefin feed rate, and working gas flow rate on the pyrolysis results was experimentally investigated. It was found that, with proper parameter control, approximately complete conversion of carbon in polyolefin could be obtained, with a C2H2 selectivity higher than 80% and a C2H2 yield higher than 70%. These results not only create new opportunities for the reuse of polymer waste, but are also instructive for the green production of C2H2.

  8. Hetero-Diels–Alder reactions of hetaryl and aryl thioketones with acetylenic dienophiles

    Directory of Open Access Journals (Sweden)

    Grzegorz Mlostoń

    2015-04-01

    Full Text Available Selected hetaryl and aryl thioketones react with acetylenecarboxylates under thermal conditions in the presence of LiClO4 or, alternatively, under high-pressure conditions (5 kbar at room temperature yielding thiopyran derivatives. The hetero-Diels–Alder reaction occurs in a chemo- and regioselective manner. The initially formed [4 + 2] cycloadducts rearrange via a 1,3-hydrogen shift sequence to give the final products. The latter were smoothly oxidized by treatment with mCPBA to the corresponding sulfones.

  9. Synthesis and Deposition of TiC-Fe Coatings by Oxygen-acetylene Flame Spraying

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A simpler and more convenient method for producing wear-resistant, TiC-reinforced coatings were investigated in this study. It consists of the simultaneous synthesis and deposition of TiC-Fe materials by oxyacetylene flame spraying.Solid reagents bound together to form a single particle are injected into the flame stream where an in-situ reaction occurs. The reaction products are propelled onto a substrate to form a coating. Microstructural analyses reveal that TiC and Fe are the dominant phases in the coatings. The reaction between Ti and C happens step by step along with the reactive spray powder flight, and TiC-Fe materials were mainly synthesized where the spray distance is 125~170 mm. The TiC-Fe coatings are composed of alternate TiC-rich and TiC-poor lamellae with different microhardness of 11.9~13.7 and 3.0~6.0 Gpa, respectively. Submicron and round TiC particles are dispersed within a ductile metal matrix. The peculiar microstructure is thought to be responsible for its good wear resistance, which is better nearly five times than WC-reinforced cermet coatings obtained by traditional oxyacetylene flame spray.

  10. Optical frequency standard using acetylene-filled hollow-core photonic crystal fibers

    DEFF Research Database (Denmark)

    Triches, Marco; Michieletto, Mattia; Hald, Jan

    2015-01-01

    frequency instability. The locked fiber laser shows a fractional frequency instability below 4×10−12 for averaging time up to 104 s. The lock-point repeatability over more than 1 year is 1.3×10−11, corresponding to a standard deviation of 2.5 kHz. A complete experimental investigation of the light...

  11. 49 CFR 178.59 - Specification 8 steel cylinders with porous fillings for acetylene.

    Science.gov (United States)

    2010-10-01

    ... being set at the calculated corresponding strain. (iv) Cross-head speed of the testing machine may not... percent of tensile strength. Elongation must be at least 40 percent in 2 inch or 20 percent in other cases...

  12. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Science.gov (United States)

    2010-10-01

    ...) Cross-head speed of the testing machine may not exceed 1/8 inch per minute during yield strength... increment of tensile strength above 50,000 psi to a maximum of four such increments. (n) Weld tests...: (1) Tensile test. A specimen must be cut from one cylinder of each lot of 200 or less, or welded test...

  13. Dynamic Load on a Pipe Caused by Acetylene Detonations – Experiments and Theoretical Approaches

    Directory of Open Access Journals (Sweden)

    Axel Sperber

    1999-01-01

    Full Text Available The load acting on the wall of a pipe by a detonation, which is travelling through, is not yet well characterized. The main reasons are the limited amount of sufficiently accurate pressure time history data and the requirement of considering the dynamics of the system. Laser vibrometry measurements were performed to determine the dynamic response of the pipe wall on a detonation. Different modelling approaches were used to quantify, theoretically, the radial displacements of the pipe wall. There is good agreement between measured and predicted values of vibration frequencies and the propagation velocities of transverse waves. Discrepancies mainly due to wave propagation effects were found in the amplitudes of the radial velocities. They might be overcome by the use of a dynamic load factor or improved modelling methods.

  14. Photo- and radiation chemical cycloaddition of maleic acid derivatives to ethylene and acetylene under elavated pressure

    International Nuclear Information System (INIS)

    Mirbach, M.

    1975-01-01

    Based on spectroscopic and kinetic measurements the influence of high pressure on some selected photochemical cycloaddition-reactions is studied. The photo-cycloaddition-reaction of maleic acid anhydride with ethylen has been performed under high ethylen pressures ( 90%). Surprisingly the quantum yield of the cyclo aduct decreases with increasing ethylene pressure from PHI = 0.06 at p = 1 bar to PHI = 0.022 at p = 42 bar. Based on Stern-Volmer quenching experiments, the decrease in ring formation with increasing ethylene concentrations could be explained by an endoergic triplet energy transfer from maleic acid anhydride to ethylene. The type II dissociation of butyrophenone has been quenched also with ethylene. With a lifetime for the first excited butyrophenone triplett state of tau = 6.8 x 10 -8 sec, obtained from kinetic data, the velocity constant can be calculated for this reaction with the result k 5 = 3 x 10 6 M -1 sec -1 . (orig./HK) [de

  15. The 2Πg shape resonance of acetylene anion: an investigation with the RAC method

    Czech Academy of Sciences Publication Activity Database

    Čurík, Roman; Paidarová, Ivana; Horáček, Michal

    2016-01-01

    Roč. 70, č. 7 (2016), č. článku 146. ISSN 1434-6060 R&D Projects: GA MŠk LD14088 Grant - others:COST(XE) CM1301 Institutional support: RVO:61388955 Keywords : ANALYTICAL CONTINUATION * ELECTRON-SCATTERING * COUPLING-CONSTANT Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 1.288, year: 2016

  16. Post Modification of Acetylene Functional Poly(oxindole biphenylylene) by Photoinduced CuAAC

    KAUST Repository

    Arslan, Mustafa; Cem Bicak, Tugrul; Pulido, Bruno; Nunes, Suzana Pereira; Yagci, Yusuf

    2018-01-01

    A novel strategy to obtain side chain modified poly(oxindole biphenylylene) (POXI) by photoinduced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is described. In the first step, an alkyne-functionalized poly(oxindolebiphenylylene) (POXI-alkyne) is synthesized by superacid-catalyzed condensation of isatin with aromatic hydrocarbons. Subsequently, poly(ethylene glycol) methyl ether (Me-PEG), 1-pyrenemethanol (Py-OH) and 1,3-dibromopropane (DBP) are functionalized by azide groups via simple nucleophilic substitution reaction. Visible-light-induced CuAAC reaction between POXI-alkyne and the corresponding azide functionalized click components employing dibenzoyldiethylgermane (DBDEG) as photoactivator resulted in the formation of POXI-PEG, POXI-Py and insoluble network, respectively. Successful modification of POXI was confirmed by the spectral, (1H NMR, FT-IR, Fluorescence), chromatographic (GPC) and thermal (DSC) investigations.

  17. An Ideal Molecular Sieve for Acetylene Removal from Ethylene with Record Selectivity and Productivity

    NARCIS (Netherlands)

    Li, B.; Cui, X.; O'Nolan, D.; Wen, H.-M.; Jiang, M.; Krishna, R.; Wu, H.; Lin, R.-B.; Chen, Y.-S.; Yuan, D.; Xing, H.; Zhou, W.; Ren, Q.; Qian, G.; Zaworotko, M.J.; Chen, B.

    2017-01-01

    Realization of ideal molecular sieves, in which the larger gas molecules are completely blocked without sacrificing high adsorption capacities of the preferred smaller gas molecules, can significantly reduce energy costs for gas separation and purification and thus facilitate a possible

  18. Preparation of conjugated poly(ethyl acetylene carboxylate) as optical limiter of laser radiation

    International Nuclear Information System (INIS)

    Allaf, A. W.; Al-Zier, A.; Al-Naima, D.

    2009-03-01

    The optical limiting action of poly (ethylacetylene carboxylate) dissolved in dichloroethane were investigated under irradiation with 8 ns laser pulses at 532 nm. The optical limiting measurements were performed at a series of concentrations. The threshold limiting fluence was observed for high concentrations at 5 J/cm 2 with a transmission of about 20 %. No optical limiting action was observed at very low concentration of the prepared polymer in the dichloroethane solvent. The observed data show that poly (ethylacetylene carboxylate) has the potential for the use as optical limiting material for future applications. (author)

  19. Hydropyrolysis of n-Hexane and Toluene to Acetylene in Rotating-Arc Plasma

    Directory of Open Access Journals (Sweden)

    Jie Ma

    2017-07-01

    Full Text Available Thermal plasma pyrolysis is a powerful technology for converting waste or low-value materials to valuable gaseous hydrocarbons. This paper presents for the first time the hydropyrolysis of n-hexane and toluene in a rotating-arc plasma reactor. Effects of the mole ratio of H/C in the feed, power input and magnetic induction were investigated to evaluate the reaction performance. A lower H/C ratio could lead to a lower yield of C2H2 and lower specific energy consumption, and there existed an optimum range of power input for both n-hexane and toluene pyrolysis within the investigated range. The yield of C2H2 in n-hexane and toluene pyrolysis could reach 85% and 68%, respectively, with respective specific energy consumption (SEC of 13.8 kWh/kg·C2H2 and 19.9 kWh/kg·C2H2. Compared with the results reported in literature, the rotating-arc plasma process showed higher C2H2 yield and lower energy consumption, which is attributed to the better initial mixing of the reactant with the hot plasma gas and the more uniform temperature distribution.

  20. CCDC 1420580: Experimental Crystal Structure Determination : catena-[(mu-4,4'-sulfonyldibenzoato)-calcium acetylene

    KAUST Repository

    Plonka, Anna M.

    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.

  1. Synthesis of panax acetylenes: chiral syntheses of acetylpanaxydol, PQ-3 and panaxydiol.

    Science.gov (United States)

    Satoh, Mitsuru; Watanabe, Mitsuo; Kawahata, Masatoshi; Mohri, Kunihiko; Yoshida, Yuki; Isobe, Kimiaki; Fujimoto, Yasuo

    2004-04-01

    Acetylpanaxydol (1-Ac), PQ-3 (2) and panaxydiol (3) and their optical isomers were synthesized from L-(+)-diethyl tartrate. The absolute configurations of 1-Ac, 2 and 3 were determined to be 1-Ac (3R,9R,10S), 2 (9R,10S) and 3 (3R,10S), respectively, by comparisons of their optical rotations and the NMR data of their MTPA esters with those of natural products.

  2. Gaseous carburising of self-passivating Fe–Cr-Ni alloys in acetylene-hydrogen mixtures

    DEFF Research Database (Denmark)

    Christiansen, Thomas; Hummelshøj, Thomas Strabo; Somers, Marcel A. J.

    2011-01-01

    temperatures, carbon stabilised expanded austenite develops, which has high hardness, while retaining the corrosion performance of the untreated alloy; for relatively high temperatures, Cr based carbides develop, and eventually, the material deteriorates by metal dusting corrosion.......Gaseous carburising of self-passivating Fe–Cr–Ni alloys in acetylene–hydrogen was investigated for temperatures up to 823 K. Acetylene–hydrogen gas mixtures allow both the activation of the surface and the subsequent carburising at a high and adjustable carburising potential. For relatively low...

  3. Pore chemistry and size control in hybrid porous materials for acetylene capture from ethylene

    KAUST Repository

    Cui, X.; Chen, K.; Xing, H.; Yang, Q.; Krishna, R.; Bao, Z.; Wu, H.; Zhou, W.; Dong, Xinglong; Han, Y.; Li, B.; Ren, Q.; Zaworotko, M. J.; Chen, B.

    2016-01-01

    The trade-off between physical adsorption capacity and selectivity of porous materials is a major barrier for efficient gas separation and purification through physisorption. We report control over pore chemistry and size in metal coordination

  4. Hydrogenase activity in Azospirillum brasilense is inhibited by nitrite, nitric oxide, carbon monoxide, and acetylene

    Energy Technology Data Exchange (ETDEWEB)

    Tibelius, K.H.; Knowles, R.

    1984-10-01

    Nitrite, NO, CO, and C/sub 2/H/sub 2/ inhibited O/sub 2/-dependent H/sub 2/ uptake (H/sup 3/H oxidation) in denitrifying Azospirillum brasilense Sp7 grown anaerobically on N/sub 2/O or NO/sub 3//sup -/. The apparent K/sub i/ values for inhibition of O/sub 2/-dependent H/sub 2/ uptake were 20 ..mu..M for NO/sub 2//sup -/, 0.4 ..mu..M for NO, 28 ..mu..M for CO, and 88 ..mu..M for C/sub 2/H/sub 2/. These inhibitors also affected methylene blue-dependent H/sub 2/ uptake, presumably by acting directly on the hydrogenase. Nitrite and NO inhibited H/sub 2/ uptake irreversibly, whereas inhibition due to CO was easily reversed by repeatedly evacuating and backfilling with N/sub 2/. The C/sub 2/H/sub 2/ inhibition was not readily reversed, partly due to difficulty in removing the last traces of this gas from solution. The NO/sub 2//sup -/ inhibition of malate-dependent respiration was readily reversed by repeatedly washing the cells, in contrast to the effect of NO/sub 2//sup -/ on H/sub 2/-dependent respiration. These results suggest that the low hydrogenase activities observed in NO/sub 3//sup -/-grown cultures of A. brasilense may be due to the irreversible inhibition of hydrogenase by NO/sub 2//sup -/ and NO produced by NO/sub 3//sup -/ reduction.

  5. Post Modification of Acetylene Functional Poly(oxindole biphenylylene) by Photoinduced CuAAC

    KAUST Repository

    Arslan, Mustafa

    2018-02-08

    A novel strategy to obtain side chain modified poly(oxindole biphenylylene) (POXI) by photoinduced copper(I)-catalyzed azide-alkyne cycloaddition (CuAAC) click reaction is described. In the first step, an alkyne-functionalized poly(oxindolebiphenylylene) (POXI-alkyne) is synthesized by superacid-catalyzed condensation of isatin with aromatic hydrocarbons. Subsequently, poly(ethylene glycol) methyl ether (Me-PEG), 1-pyrenemethanol (Py-OH) and 1,3-dibromopropane (DBP) are functionalized by azide groups via simple nucleophilic substitution reaction. Visible-light-induced CuAAC reaction between POXI-alkyne and the corresponding azide functionalized click components employing dibenzoyldiethylgermane (DBDEG) as photoactivator resulted in the formation of POXI-PEG, POXI-Py and insoluble network, respectively. Successful modification of POXI was confirmed by the spectral, (1H NMR, FT-IR, Fluorescence), chromatographic (GPC) and thermal (DSC) investigations.

  6. Microstructure and performance of titanium oxide coatings sprayed by oxygen-acetylene flame

    Czech Academy of Sciences Publication Activity Database

    Ctibor, Pavel; Štengl, Václav; Zahálka, F.; Murafa, Nataliya

    2011-01-01

    Roč. 10, č. 3 (2011), s. 403-407 ISSN 1474-905X R&D Projects: GA AV ČR IAAX00430803 Institutional research plan: CEZ:AV0Z20430508; CEZ:AV0Z40320502 Keywords : Plasma spraying * flame spraying * photocatalysis * TiO2 Subject RIV: JH - Ceramics, Fire-Resistant Materials and Glass Impact factor: 2.584, year: 2011

  7. Characterizing dusty argon-acetylene plasmas as a first step to understand dusty EUV environments

    NARCIS (Netherlands)

    Wetering, van de F.M.J.H.; Nijdam, S.; Kroesen, G.M.W.

    2012-01-01

    In extreme ultraviolet (EUV) lithography, ionic and particulate debris coming from the plasma source plays an important role. We started up a project looking at the principles of particle formation in plasmas and the interaction with EUV radiation. To this end, we study a low-pressure (10 Pa)

  8. High Temperature Chemistry of Chlorinated Acenaphthylene. 3C Bay Acetylene Additions and Annealing by Five-Membered Ring Shifts.

    Science.gov (United States)

    McIntosh, Grant J; Russell, Douglas K

    2015-12-24

    Experimental and theoretical results concerning the growth and isomerization of chlorinated acenaphthylene, C12H8, during the pyrolysis of chlorohydrocarbons are presented here. A fullerene subunit, C12H8, is a useful system to investigate regarding C60 formation. However, direct experimental observation of isomerization and annealing processes in particular are difficult to confirm due to the high symmetry of the parent molecule. Chlorination lowers the symmetry, essentially labeling carbon atoms, allowing growth and isomerization to be followed directly. Pyrolysis of dichloro- and trichloroethylene, and their copyrolyses with trichlorobenzenes, provides an efficient and general source of chlorinated acenaphthylenes in a range of degrees of chlorination and over a number of unique congeners. Analysis of congener yields as a function of reagents employed, guided by DFT/B3LYP/6-311G(d,p) level calculations, strongly suggests that C2 addition across three-carbon bays in naphthalene is a major driver of growth. Additionally, extremely facile five-membered ring shifts are operative, with chlorine promoting isomerization. Theoretical study of C16H10- and C18H10-based congeners indicate that this is a general phenomenon, and with chlorine also favoring internal cyclopentafused rings in addition to increased isomerization rates, this suggests halogen moieties may be an important feature for efficient fullerene growth.

  9. Synthesis of Hexadehydrotribenzo[a,e,i][12]annulenes by Acetylene Insertion into an Open-Chain Precursor

    Czech Academy of Sciences Publication Activity Database

    Dudič, Miroslav; Císařová, I.; Michl, Josef

    2012-01-01

    Roč. 77, č. 1 (2012), s. 68-74 ISSN 0022-3263 EU Projects: European Commission(XE) 227756 - DIPOLAR ROTOR ARRAY Institutional research plan: CEZ:AV0Z40550506 Keywords : one-step synthesis * alkyne metathesis * convenient synthesis * derivatives * macrocycle Subject RIV: CC - Organic Chemistry Impact factor: 4.564, year: 2012

  10. Effective Acetylene/Ethylene Separation at Ambient Conditions by a Pigment-Based Covalent-Triazine Framework

    KAUST Repository

    Lu, Yue; He, Jia; Chen, Yanli; Wang, Heng; Zhao, Yunfeng; Han, Yu; Ding, Yi

    2017-01-01

    A novel covalent-triazine framework (CTF-PO71) is designed and prepared from an organic pigment molecule for high-performance gas separation. The functional sites with different electrostatic potentials on the pore surface of CTF-PO71 demonstrate a strong interaction between C2H2 and CTF-PO71 to achieve preferential adsorption of C2H2 over C2H4, thus enabling effective capture of a trace amount of C2H2 from the gas mixture. This is the first organic porous polymer that is capable of separating C2H2 and C2H4. The commercial availability and the low cost of the pigment as well as the high stability of the resultant framework endow CTF-PO71 with a significant potential for practical applications.

  11. An Experimental and Theoretical Study of the Mechanism of Stannylcupration of α,β-Acetylenic Ketones and Esters

    DEFF Research Database (Denmark)

    Ahlquist, Mårten Sten Gösta; Nielsen, Thomas Eiland; Le Quement, Sebastian

    2006-01-01

    is observed, whereas for the corresponding ynoate substrate, the stereoselectivity can be affected by the reaction conditions: in the presence of methanol as proton donor, the initial syn-addition product can be trapped, whereas a syn/anti mixture is obtained in a non-protic solvent. This is in sharp contrast...

  12. Development of vinylic and acetylenic functionalized structures based on high permeable glassy polymers as membrane materials for gas mixtures separation

    Science.gov (United States)

    Roizard, D.; Kiryukhina, Y.; Masalev, A.; Khotimskiy, V.; Teplyakov, V.; Barth, D.

    2013-03-01

    There are several challenging separation problems in industries which can be solved with the help of membrane technologies. It is the case for instance of the purification of gas energy carriers (i.e. H2, CH4) from CO2 as well as the CO2 recovery from flue gas. Glassy polymers containing trimethylsilyl residues like poly(1-trimethylsilyl-1-propyne) [PTMSP] and polyvinyltrimethylsilane [PVTMS] are known to exhibit good membrane properties for gas separation. This paper reports two ways of improving their performances based on the controlled introduction of selective groups - alkyl imidazomium salts (C4I) and polyethyleneglycol (M-PEG)- able to enhance CO2 selectivity. CO2 Isotherm sorption data and permeability measurements have shown that the membrane performances could be significantly improved when C4I and M-PEG were introduced as residues covalently bounded to the main polymer chain. Moreover the introduced bromine reactive centres could also be used to induce chemical crosslinking giving rise to more resistant and stable membranes to organic vapours. With the C4I groups, the CO2 sorption could be enhanced by a factor 4.4.

  13. Dissimilatory reduction of nitrate and nitrite in the bovine rumen: nitrous oxide production and effect of acetylene.

    OpenAIRE

    Kaspar, H F; Tiedje, J M

    1981-01-01

    15N tracer methods and gas chromatography coupled to an electron capture detector were used to investigate dissimilatory reduction of nitrate and nitrite by the rumen microbiota of a fistulated cow. Ammonium was the only 15N-labeled end product of quantitative significance. Only traces of nitrous oxide were detected as a product of nitrate reduction; but in experiments with nitrite, up to 0.3% of the added nitrogen accumulated as nitrous oxide, but it was not further reduced. Furthermore, whe...

  14. The reaction of C5N− with acetylene as a possible intermediate step to produce large anions in Titan's ionosphere

    Czech Academy of Sciences Publication Activity Database

    Lindén, F.; Žabka, Ján; Polášek, Miroslav; Zymak, Illia; Geppert, W. D.

    2018-01-01

    Roč. 20, č. 8 (2018), s. 5377-5388 ISSN 1463-9076 R&D Projects: GA MŠk(CZ) LD14024; GA ČR(CZ) GA17-14200S Grant - others:COST(XE) CM1401 Institutional support: RVO:61388955 Keywords : investigation * C5N- * Titan Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 4.123, year: 2016

  15. The tertiary glycerin of acetylene and ethylen lines and their chemical transformations; Tretichnie glitserini atsetilenovogo ryadov i ih himicheskie prevrasheniya

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, V I

    1961-07-01

    In this monograph are summarised results of many years investigations, lead by author with group of colleagues of Institute of chemistry of Republic of Tajikistan in the field of synthesis of some new compounds classes of organic chemistry.

  16. Experimental and theoretical study of the reactions between neutral vanadium oxide clusters and ethane, ethylene, and acetylene.

    Science.gov (United States)

    Dong, Feng; Heinbuch, Scott; Xie, Yan; Rocca, Jorge J; Bernstein, Elliot R; Wang, Zhe-Chen; Deng, Ke; He, Sheng-Gui

    2008-02-13

    Reactions of neutral vanadium oxide clusters with small hydrocarbons, namely C2H6, C2H4, and C2H2, are investigated by experiment and density functional theory (DFT) calculations. Single photon ionization through extreme ultraviolet (EUV, 46.9 nm, 26.5 eV) and vacuum ultraviolet (VUV, 118 nm, 10.5 eV) lasers is used to detect neutral cluster distributions and reaction products. The most stable vanadium oxide clusters VO2, V2O5, V3O7, V4O10, etc. tend to associate with C2H4 generating products V(m)O(n)C2H4. Oxygen-rich clusters VO3(V2O5)(n=0,1,2...), (e.g., VO3, V3O8, and V5O13) react with C2H4 molecules to cause a cleavage of the C=C bond of C2H4 to produce (V2O5)(n)VO2CH2 clusters. For the reactions of vanadium oxide clusters (V(m)O(n)) with C2H2 molecules, V(m)O(n)C2H2 are assigned as the major products of the association reactions. Additionally, a dehydration reaction for VO3 + C2H2 to produce VO2C2 is also identified. C2H6 molecules are quite stable toward reaction with neutral vanadium oxide clusters. Density functional theory calculations are employed to investigate association reactions for V2O5 + C2H(x). The observed relative reactivity of C2 hydrocarbons toward neutral vanadium oxide clusters is well interpreted by using the DFT calculated binding energies. DFT calculations of the pathways for VO3+C2H4 and VO3+C2H2 reaction systems indicate that the reactions VO3+C2H4 --> VO2CH2 + H2CO and VO3+C2H2 --> VO2C2 + H2O are thermodynamically favorable and overall barrierless at room temperature, in good agreement with the experimental observations.

  17. Sonogashira reactions of alpha and beta-1-ethynyl-2-deoxyribosides: synthesis of acetylene-extended C-nucleosides

    Czech Academy of Sciences Publication Activity Database

    Bobula, T.; Hocek, Michal; Kotora, M.

    2010-01-01

    Roč. 66, č. 2 (2010), s. 530-536 ISSN 0040-4020 R&D Projects: GA MŠk 1M0508; GA AV ČR IAA400550902 Institutional research plan: CEZ:AV0Z40550506 Keywords : alkynes * C-nucleosides * aryl halides * cross-coupling reactions Subject RIV: CC - Organic Chemistry Impact factor: 3.011, year: 2010

  18. Study of interferences in the atomic - absorption and emission of barium in nitrous oxide/acetylene flame

    International Nuclear Information System (INIS)

    Curtius, A.J.; Couto, M.I.

    1979-01-01

    The interferences of several ions that are present in oifield water and sea water in the atomic absorption and emission of barium were investigated. It was verified that the interferences of sodium, potassium, calcium, strontium and chloride are the most important. The indirect method for the determination of sulfate by measuring barium by atomic absorption after precipitating barium sulfate with an excess of barium chloride, should not be used for highly salted matrix. To avoid the interferences that are not compensated by an ionization supressor, the measurement of barium by the standard addition method or a previous sulfate separation is recommended. (Author) [pt

  19. Ionic .pi.-conjugated polyelectrolytes by catalyst free polymerization of bis(pyridyl)acetylenes and bis[(pyridyl)ethynyl]benzenes

    Czech Academy of Sciences Publication Activity Database

    Faukner, T.; Trhlíková, Olga; Zedník, J.; Sedláček, J.

    2015-01-01

    Roč. 216, č. 14 (2015), s. 1540-1554 ISSN 1022-1352 R&D Projects: GA ČR GAP108/12/1143 Institutional support: RVO:61389013 Keywords : conjugated polymers * ionic polymers * polyacetylenes Subject RIV: CD - Macromolecular Chemistry Impact factor: 2.495, year: 2015

  20. Effective Acetylene/Ethylene Separation at Ambient Conditions by a Pigment-Based Covalent-Triazine Framework

    KAUST Repository

    Lu, Yue

    2017-10-24

    A novel covalent-triazine framework (CTF-PO71) is designed and prepared from an organic pigment molecule for high-performance gas separation. The functional sites with different electrostatic potentials on the pore surface of CTF-PO71 demonstrate a strong interaction between C2H2 and CTF-PO71 to achieve preferential adsorption of C2H2 over C2H4, thus enabling effective capture of a trace amount of C2H2 from the gas mixture. This is the first organic porous polymer that is capable of separating C2H2 and C2H4. The commercial availability and the low cost of the pigment as well as the high stability of the resultant framework endow CTF-PO71 with a significant potential for practical applications.

  1. Nitrogen fixation (Acetylene reduction) in the sediments of the pluss-see : with special attention to the role of sedimentation

    NARCIS (Netherlands)

    Blauw, T.S.

    1987-01-01

    Sediments of productive lakes are usually rich in organic matter and, except for a thin surficial layer, anaerobic. These conditions seem to be favourable for heterotrophic nitrogen fixation. However, these sediments also contain relatively high ammonium concentrations. Ammonium represses

  2. Dual-Comb Spectroscopy of the ν_1+ ν_3 Band of Acetylene: Intensity and Transition Dipole Moment

    Science.gov (United States)

    Iwakuni, Kana; Okubo, Sho; Yamada, Koichi MT; Inaba, Hajime; Onae, Atsushi; Hong, Feng-Lei; Sasada, Hiroyuki

    2017-06-01

    The ν_1+ν_3 vibration band of ^{12}C_2H_2 is recorded with a homemade dual-comb spectrometer. The spectral resolution and the accuracy of frequency determination are high, and the bandwidth is broad enough to take spectrum of the whole band in one shot. The last remarkable competence enables us to record all the spectral lines under constant experimental conditions. The linewidth and line strength of the P(26) to R(29) transitions are determined by fitting the line profile to Lambert-Beer's law with a Voigt function. In the course of analysis, we found the ortho-para dependence of the pressure-broadening coefficient. This time, we have determined the transition dipole moment of the ν_1+ν_3 band. It is noted that the transition dipole moment determined from the ortho lines agrees with that from the para lines. S. Okubo et al., Applied Physics Express 8, 082402 (2015). K.Iwakuni et al., 71th ISMS, WK15 K. Iwakuni et al., Physical Review Letters 117, 143902 (2016).

  3. New examples of the vinylation of NH-heterocycles with acetylene at atmospheric pressure in the KOH-DMSO system

    Energy Technology Data Exchange (ETDEWEB)

    Trofimov, B.A.; Nesterenko, R.N.; Mikhaleva, A.I.; Shapiro, A.B.; Aliev, I.A.; Yakovleva, I.V.; Kalabin, G.A.

    1986-10-01

    Vinylation of 2-hetarylpyrroles, 4,5-dihydrobenzo(g)indole, and 1,2,3,4-tetrahydro-..gamma..-carbinols at atmospheric pressure in the superbasic system KOH-DMSO at 100-120/sup 0/C has given the corresponding N-vinyl derivatives in yields of 92-99%.

  4. A CATALYST, A PROCESS FOR SELECTIVE HYDROGENATION OF ACETYLENE TO ETHYLENE AND A METHOD FOR THE MANUFACTURE OF THE CATALYST

    DEFF Research Database (Denmark)

    2009-01-01

    A catalyst comprising a mixture of metal A selected from the group of Fe, Co and Ni and metal B selected from the group of Zn and Ga, and a support material, wherein the two metals are present in an intermetallic composition; A method for the manufacture of the catalyst; and the use of above...

  5. Radiosynthesis and preliminary evaluation of Z.W.-90 and Z.W.-110, two novel acetylenic pyridines for imaging the nicotinic receptors

    Energy Technology Data Exchange (ETDEWEB)

    Kassiou, M.; Giboureau, N. [Sydney Univ., Brain and Mind Research Institute, NSW (Australia); Chellapan, S.; Wei, Z.L.; Kozikowski, A. [Illinois Univ., Chicago, Dept. of Medicinal Chemistry and Pharmacognosy, IL (United States); Henderson, D.; Fulton, R. [RPAH Sydney, Dept. PET and Nuclear Medicine (Australia); Xiao, Y.; Kellar, K. [Georgetown Univ., Dept. of Pharmacology, School of Medicine, Washington, DC (United States); Guilloteau, D.; Emond, P. [Institut National de la Sante et de la Recherche Medicale (INSERM), U619, 37 - Tours (France); Dolle, F. [Service Hospitalier Frederic Joliot, CEA/DSV, Institut d' Imagerie BioMedicale, 91 - Orsay (France)

    2008-02-15

    Central nicotinic acetylcholine receptors (n.A.Ch.R.s) have been implicated in learning memory processes and neuro-psychiatric disorders. Recently it was reported that the introduction of a substituted alkynyl group into the C-5 position of the pyridinyl ring of A-84543, significantly increased the selectivity for the n.A.Ch.R. containing {beta}{sub 2} subunits over {beta}{sub 4} subunits. Two selected candidates, Z.W.-90 and Z.W.-110 were labelled with carbon{sup 11} and evaluated in vivo.{sup 11}C Z.W.-90 penetrated rapidly into the brain, with maximum uptake in the thalamus and cerebellum 2 min post injection followed by clearance. The washout from cerebellum was faster than from thalamus, suggesting that specific binding can be optimally measured at 20 min post injection; Pretreatment of the baboon with nicotine resulted in markedly decreased uptake of the radioligand. {sup 11}C Z.W.-110 also penetrated rapidly into the brain, with a high evident uptake in the thalamus within 5 min. Surprisingly there was also considerable uptake in the striatum. Pretreatment with nicotine resulted in inhibition of uptake of 8 and 1%, in the thalamus and cerebellum, respectively. In pretreatment studies using unlabelled Z.W.-110, 32% inhibition of radioligand uptake was observed in the thalamus and striatum while uptake in the cerebellum was reduced by 24 %.While further work will be necessary in the development of optimal imaging agents for n.A.Ch.Rs, efforts will be made to examine the potential of these newly developed radioligands to serve diagnostic agents in the early detection of neurological disorders. (N.C.)

  6. Degradation and cis-to-trans isomerization of poly[(2,4-difluorophenyl)acetylene]s of various initial molecular weight: SEC, NMR, DLS and EPR study

    Czech Academy of Sciences Publication Activity Database

    Trhlíková, O.; Zednik, J.; Matějíček, P.; Horáček, Michal; Sedláček, J.

    2013-01-01

    Roč. 98, č. 9 (2013), s. 1814-1826 ISSN 0141-3910 R&D Projects: GA ČR(CZ) GAP108/11/1661 Institutional support: RVO:61388955 Keywords : 1,3,5-Tris(2,4-difluorophenyl)benzene * Conjugated polymers * Degradation Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.633, year: 2013

  7. Theoretical Study of 1,3-Dipolar Cycloadditions Regioselectivity of Benzyl Azide with Glycosyl-O Acetylene Using Density Functional Theory (DFT

    Directory of Open Access Journals (Sweden)

    Adib Ghaleb

    2017-12-01

    Full Text Available A theoretical study of 1,3-cycloaddition has been carried out using density functional theory (DFT methods at the B3LYP/6-31G* level. The regioselectivity of the reaction have been clarified through different theoretical approaches: Case of a Two-Center Process (Domingo approach, HSAB principle (Gazquez and Mendez approach, and the activation energy calculations. The analysis of results shows that the reaction takes place along concerted asynchronous mechanism and the isomer meta is favored, in agreement with the experiment results. DOI: http://dx.doi.org/10.17807/orbital.v9i5.1017 

  8. Dynamic study of carbon nanotube growth and catalyst morphology evolution during acetylene decomposition on Co/SBA-15 in an environmental TEM

    DEFF Research Database (Denmark)

    s Aires, F. J. Cadete Santo; Epicier, T.; Wagner, Jakob Birkedal

    2012-01-01

    -3/10-2 mbar range was used to decrease the growth rate to allow real-time observation of the formation of CNTs over several minutes. These conditions also reduced the coking of the nanoparticles and favoured the formation of tubular structures. Two types of CNTs following the tip-growth mechanism...

  9. Biological Evaluation, Overpressured Layer Chromatography (OPLC) separation and Isolation of a New Acetylenic Derivative Compound from Prangos platychlaena ssp. platychlaena Fruit Essential Oils

    Science.gov (United States)

    In the present work, fruits of Prangos platychlaena Boiss. ex Tchihat. ssp. platychlaena (Apiaceae) collected from eastern (Sample A) and central (Sample B) parts of Turkey were subjected to hydrodistillation to yield essential oils (EOs). The chemical composition of P. platychlaena ssp. platychlaen...

  10. Synthesis of acetylene linked double-nucleobase nucleos(t)ide building blocks and polymerase construction of DNA containing cytosines in the major groove

    Czech Academy of Sciences Publication Activity Database

    Kielkowski, Pavel; Pohl, Radek; Hocek, Michal

    2011-01-01

    Roč. 76, č. 9 (2011), s. 3457-3462 ISSN 0022-3263 R&D Projects: GA MŠk LC512; GA ČR GA203/09/0317 Institutional research plan: CEZ:AV0Z40550506 Keywords : nucleoside triphosphates * functionalized DNA * cross - coupling reactions * nucleic-acids Subject RIV: CC - Organic Chemistry Impact factor: 4.450, year: 2011

  11. CCDC 1420583: Experimental Crystal Structure Determination : catena-[(mu-22,25-bis(4-carboxyphenyl)[11,21:24,31-terphenyl]-14,34-dicarboxylato)-calcium acetylene

    KAUST Repository

    Plonka, Anna M.

    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.

  12. Long-Chain Acetylenic Ketones from the Micronesian Sponge Haliclona sp. Importance of the 1-yn-3-ol Group for Antitumor Activity

    Directory of Open Access Journals (Sweden)

    Guang-Xiong Zhou

    2003-11-01

    Full Text Available Abstract: Two new long-chain C33 polyacetylenic compounds, halicynones A and B were isolated from the marine sponge Haliclona sp. along with known analogs. The known compound pellynol A possessing a 1-yn-3-ol terminus, exhibited strong antitumor activity against the human colon tumor cell line HCT-116 (IC50 0.026 μg/mL, however, the corresponding 1-yn-3-one, halicynone A, was inactive, which suggests an important role for the terminal 1-yn-3-ol functional group in mediating cytotoxic activity.

  13. Fixation of tritium in a highly stable polymer form

    International Nuclear Information System (INIS)

    Steinberg, M.; Colombo, P.; Pruzansky, J.

    1977-01-01

    A method for the fixation of tritium comprises reacting tritiated water with calcium carbide to produce calcium hydroxide and tritiated acetylene, polymerizing the acetylene, and then incorporating the polymer in a solidifying matrix. 2 claims

  14. Transition-Metal-Free C-Vinylation of Ketones with Acetylenes: A Quantum-Chemical Rationalization of Similarities and Differences in Catalysis by Superbases MOH/DMSO and tBuOM/DMSO (M = Na, K).

    Science.gov (United States)

    Orel, Vladimir B; Vitkovskaya, Nadezhda M; Kobychev, Vladimir B; Trofimov, Boris A

    2018-04-06

    Transition-metal-free C-vinylation of acetone with phenylacetylene catalyzed by superbases MOH/DMSO and tBuOM/DMSO (M = Na, K) has been theoretically evaluated in the B3LYP/6-311++G**//B3LYP/6-31+G* approach to rationalize similarities and differences in activity of the above catalytic systems. The close solvate surroundings of sodium and potassium tert-butoxides have been studied. Formation of tBuOM· nDMSO complexes and their structure and thermodynamic stability are discussed in comparison with similar complexes of alkali-metal hydroxides MOH· nDMSO. Activation barriers of the title reaction in the presence of tBuOM· nDMSO complexes are found to be less than those with MOH· nDMSO complexes participating.

  15. Synthesis of Stable and Soluble One-Handed Helical Homopoly(substituted acetylenes without the Coexistence of Any Other Chiral Moieties via Two-Step Polymer Reactions in Membrane State: Molecular Design of the Starting Monomer

    Directory of Open Access Journals (Sweden)

    Takashi Kaneko

    2012-01-01

    Full Text Available A soluble and stable one-handed helical poly(substituted phenylacetylene without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer followed by two-step polymer reactions in membrane state: (1 removing the chiral groups (desubstitution; and (2 introduction of achiral long alkyl groups at the same position as the desubstitution to enhance the solubility of the resulting one-handed helical polymer (resubstitution. The starting chiral monomer should have four characteristic substituents: (i a chiral group bonded to an easily hydrolyzed spacer group; (ii two hydroxyl groups; (iii a long rigid hydrophobic spacer between the chiral group and the polymerizing group; (iv a long achiral group near the chiral group. As spacer group a carbonate ester was selected. The two hydroxyl groups formed intramolecular hydrogen bonds stabilizing a one-handed helical structure in solution before and after the two-step polymer reactions in membrane state. The rigid long hydrophobic spacer, a phenylethynylphenyl group, enhanced the solubility of the starting polymer, and realized effective chiral induction from the chiral side groups to the main chain in the asymmetric-induced polymerization. The long alkyl group near the chiral group avoided shrinkage of the membrane and kept the reactivity of resubstitution in membrane state after removing the chiral groups. The g value (g = ([θ]/3,300/ε for the CD signal assigned to the main chain in the obtained final polymer was almost the same as that of the starting polymer in spite of the absence of any other chiral moieties. Moreover, since the one-handed helical structure was maintained by the intramolecular hydrogen bonds in a solution, direct observation of the one-handed helicity of the final homopolymer has been realized in CD for the solution for the first time.

  16. Concentrations of ethane (C2H6) in the lower stratosphere and upper troposphere and acetylene (C2H2) in the upper troposphere deduced from Atmospheric Trace Molecule Spectroscopy/Spacelab 3 spectra

    Science.gov (United States)

    Rinsland, C. P.; Russell, J. M., III; Zander, R.; Farmer, C. B.; Norton, R. H.

    1987-01-01

    This paper reports the results of the spectroscopic analysis of C2H6 and C2H2 absorption spectra obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument flown on the Shuttle as part of the Spacelab 3 mission. The spectra were recorded during sunset occultations occurring between 25 deg N and 31 deg N latitudes, yielding volume-mixing ratio profiles of C2H6 in the lower stratosphere and the upper troposphere, and an upper tropospheric profile of C2H2. These results compare well with previous in situ and remote sounding data obtained at similar latitudes and with model calculations. The results demonstrate the feasibility of the ATMOS instrument to sound the lower atmosphere from space.

  17. Infrared study of the nature of the copper ion--alkyne bond in Y zeolite

    International Nuclear Information System (INIS)

    Pichat, P.

    1975-01-01

    The infrared spectra of acetylene, deuterated acetylene, propyne, and but-2-yne, chemisorbed in Cu, Na--Y zeolites, which have undergone various treatments, were studied. It is concluded that the OH groups interact only with the weakly absorbed molecules, the Cu + ions are not involved, the acetylenic hydrogen atoms do not take part in the bonding, the Cu 2+ ion--alkyne bone results mainly from π donation from the unsaturated hydrocarbon to the metallic ion. (auth)

  18. Nitrogen fixation on a coral reef

    Energy Technology Data Exchange (ETDEWEB)

    Mague, T.H.; Holm-Hansen, O.

    1975-06-01

    Benthic, heterocystous blue-green algae (genera Calothrix, Hormothamnion and Nostoc) from Eniwetok Atoll were found to reduce acetylene at rapid rates. Slight acetylene reduction was associated with samples of Rhizoclonium (Chlorophyceae) and Oscillatoria (a cyanophyte lacking heterocysts), but this may have been due to contamination by epiphytes. There was virtually no acetylene reduction by phytoplankton, and nutrient enrichment experiments failed to selectively increase the numbers or activity of N/sub 2/-fixing algae in surface water samples. The Nostoc required light for acetylene reduction. Nitrogen fixation by this species could have supplied up to 11 ..mu..g N/cm/sup 2//day to the ecosystem. (auth)

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

    Indian Academy of Sciences (India)

    Study of diffusivity of acetylene adsorbed in Na-Y zeolite by quasi-elastic neutron scattering (QENS) measurements at temperatures of 300, 325 and 350 K is reported. A model in which the acetylene molecules undergo random-walk diffusion characterized by a Gaussian distribution of jump lengths inside zeolite cages ...

  20. African Journal of Science and Technology (AJST) REACTIONS OF ...

    African Journals Online (AJOL)

    opiyo

    Acetylenic amines have been used in the synthesis of potential biologically active heterocyclic compounds. Recently the anticonvulsant activity of some acetylenic quinazolinone derivatives have been evaluated and most of them exhibited significant activity in the seizure threshold test with subcutaneous pentylenetetrazole.

  1. 1,4-diphenylbutadiyne as a potential tritium getter

    International Nuclear Information System (INIS)

    Miller, H.H.; Bissell, E.E.; Tsugawa, R.T.; Souers, P.C.

    1980-01-01

    Research on the acetylene compound 1,4-diphenylbutadiyne is an effort to develop an air-operative tritium gas scavenger. T 2 adds to the acetylene bond of the organic in the presence of a metal catalyst. The catalyst also stimulates the oxidation reaction as well. The butadiyne compound has shown good reaction efficiency at 300 ppM T 2 in static dry air. At this concentration 75% of the scavenged tritium was in the organic. This work has expanded to the investigation of liquid acetylenes, metal acetylene complexes, organometallics and acetylene based alcohols. The best of these compounds has gettered 100% of 10 to 500 ppM T 2 for both static and dynamic air flow conditions

  2. Synthesis of perdeuterophenylacetylene

    International Nuclear Information System (INIS)

    Kunjappu, J.T.; Prasad, C.V.C.; Gupta, H.M.; Rao, M.H.; Rao, K.N.

    1986-01-01

    The relative merits of feasible methods to synthesise phenyl acetylene-d 6 have been evaluated and a convenient path has been adopted for obtaining it in good isotopic purity. Detailed procedures for preparing the intermediate deuterated compounds like benzene-d 6 bromobenzene-d 5 , α-phenyl-d 5 -ethanol, phenyl-d 5 -ethylene, styrene dibromide-d 5 , phenyl-d 5 -acetylene, phenyl acetylene-d 6 and deuterosulphuric acid have been outlined. The infrared spectra of these deutero compounds in carbon tetrachloride solution scanned in sodium chloride liquid cells have been presented and they were used in quantitatively estimating their deuterium content. This compound is of potential use as a target material in nuclear fusion studies. (author)

  3. Kinetics of Hydrocarbon formation in a- C:H Film deposition plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Cal, E de la; Tabares, F L

    1993-07-01

    The formation of C2 and Cp hydrocarbons during the PACVD of a-C:H films from admixtures of methane with H2 and He has been investigated by mass spectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanisms of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene formation was found to be directly related to the formation of the film on top of the carburized metal. (Author) 12 refs.

  4. Kinetics of Hydrocarbon formation in a-C:H Film deposition plasmas

    International Nuclear Information System (INIS)

    Cal, E. de la; Tabares, F. L.

    1993-01-01

    The formation of C2 and Cp hydrocarbons during the PACVD of a-C:H films from admixtures of methane with H2 and He has been investigated by mass spectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanisms of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene formation was found to be directly related to the formation of the film on top of the carburized metal. (Author) 12 refs

  5. 46 CFR 56.97-40 - Installation tests.

    Science.gov (United States)

    2010-10-01

    ... attached to boilers by welding without practical means of blanking off for testing, the piping shall be...) Fixed oxygen-acetylene system piping. (b) Installation testing requirements for refrigeration, fluid...

  6. Optical Remote Sensing to Determine Strength of Nonpoint Sources: Duke Forest Validation Study (ESTCP #CP-0214)

    National Research Council Canada - National Science Library

    Varma, Ravl; Hashmonay, Ram; Kagann, Robery; Bolch, Adam

    2005-01-01

    ...-path Fourier Transform Infra-Red spectrometer (OP-FTIR). Trace gases, nitrous oxide, ethylene and acetylene, propylene and propane, are released in a controlled manner and their locations of release are recorded...

  7. Muonium-containing vinyl radicals

    International Nuclear Information System (INIS)

    Rhodes, C.J.; Symons, M.C.R.; Roduner, E.; Heming, M.

    1987-01-01

    Exposure of trimethylsilylacetylene and bis(trimethylsilyl)acetylene to positive muons gave radicals whose muon-electron hyperfine coupling constants establish that the corresponding vinyl radicals were formed. (author)

  8. Calcium and magnesium determination

    International Nuclear Information System (INIS)

    Bhattacharya, S.K.

    1982-01-01

    The roles of calcium and magnesium in human health and disease have been extensively studied. Calcium and magnesium have been determined in biological specimens by atomic absorption spectroscopy using stiochiometric nitrous oxide-acetylene flame

  9. Catalytic hydrogenation of alkyne and alkadiene impurities from alkenes. Practical and theoretical aspects

    International Nuclear Information System (INIS)

    Nikolaev, S A; Smirnov, V V; Zanaveskin, Leonid N; Zanaveskin, K L; Averyanov, Vyacheslav A

    2009-01-01

    The review is devoted to heterogeneous catalysts for selective hydrogenation of highly unsaturated impurities (dienes and acetylenes) in hydrocarbonic streams. The most promising systems are nanocomposites on the basis of palladium or gold.

  10. Growth and N2 fixation in an Alnus hirsuta (Turcz.) var. sibirica stand ...

    Indian Academy of Sciences (India)

    2013-10-01

    Oct 1, 2013 ... remains high, although varying in summer, decreasing in autumn, and .... 10% acetylene in air within glass containers of 200 mL capacity. ...... elevated CO2 and nitrogen availability on nodulation of Alnus hirsuta Turcz.

  11. Total synthesis of ciguatoxin.

    Science.gov (United States)

    Hamajima, Akinari; Isobe, Minoru

    2009-01-01

    Something fishy: Ciguatoxin (see structure) is one of the principal toxins involved in ciguatera poisoning and the target of a total synthesis involving the coupling of three segments. The key transformations in this synthesis feature acetylene-dicobalthexacarbonyl complexation.

  12. CORRELATION AMONG FLUORIDE AND METALS IN IRRIGATION ...

    African Journals Online (AJOL)

    Preferred Customer

    emissions from volcanoes and in marine aerosols. The main natural ... acetylene flame was used for the determination of the metals in soil and water samples. .... The method validation was established by spiking experiments (recovery test).

  13. Glaser coupling of polymers : side-reaction in huisgens "Click" coupling reaction and opportunity for polymers with focal diacetylene units in combination with ATRP

    NARCIS (Netherlands)

    Duxbury, C.J.; Cummins, D.M.; Heise, A.

    2009-01-01

    Atom, transfer radical polymerization (ATRP) was used in combination with Glaser type coupling, allowing the clean and efficient formation of symmetrically coupled polymers with a central diacetylene unit. The feasibility of the clean acetylene coupling was investigated with alkyne terminated

  14. Microwave-assisted efficient synthesis of 2-arylbenzo[b]furans and 2 ...

    Indian Academy of Sciences (India)

    ferrocenylbenzo[b]furans from readily prepared propargylic alcohols, ... reported microwave-enhanced Sonogashira coupling and cyclization reactions on alumina,10c but his method needs expensive trimethylsilyl-acetylene as monopro-.

  15. Influence of Pilot Flame Parameters on the Stability of Turbulent Jet Flames

    KAUST Repository

    Guiberti, Thibault F.; Cutcher, Hugh; Roberts, William L.; Masri, Assaad R.

    2016-01-01

    natural gas and liquefied petroleum gas. Various concentrations of five gases are used in the pilot stream, hydrogen, acetylene, oxygen, nitrogen, and argon, to enable a sufficient range in exploring the following parameters: pilot heat release

  16. LEAD ACCUMULATION IN THE ROADSIDE SOILS FROM HEAVY ...

    African Journals Online (AJOL)

    Preferred Customer

    ABSTRACT. The levels of lead pollution in the roadside soils of the heavy density motor ways of Eastern ... Heavy metals are not biodegradable and .... Finally, filtration was carried out using Whatman No. 1 filter ... Air-acetylene (99 % purity).

  17. Energy partitioning in elementary chemical processes

    Energy Technology Data Exchange (ETDEWEB)

    Bersohn, R. [Columbia Univ., New York, NY (United States)

    1993-12-01

    In the past year research has centered on the decomposition of hot molecules, the reaction of ethynyl radicals with hydrogen molecules and the reaction of oxygen atoms with acetylene. Reaction kinetics studies are reported for each of these systems.

  18. effect of electrochemical oxidation of a viscose rayon based ...

    African Journals Online (AJOL)

    DJFLEX

    KEYWORDS: Viscose rayon based activated carbon cloth; Sorption isotherms; Electrochemical oxidation; Arsenic .... (AAS ) in acetylene-air flame emission mode. 2.9. Quality ..... of the EO ACC thereby restricting the number of binding sites for ...

  19. Communication: An accurate calculation of the S1 C2H2 cis-trans isomerization barrier height

    International Nuclear Information System (INIS)

    Baraban, Joshua H.; Matthews, Devin A.; Stanton, John F.

    2016-01-01

    A high level ab initio calculation of the cis-trans isomerization barrier height in the first excited singlet electronic state of acetylene is found to agree very well with a recent experimental determination.

  20. Orientation dependence in collision induced electronic relaxation studied through van der Waals complexes with isomeric structures. Invited feature article

    International Nuclear Information System (INIS)

    Cheng, P.Y.; Lapierre, L.; Ju, S.S.; DeRose, P.; Dai, H.L.

    1994-01-01

    Weakly bound molecular complexes with more than one well-defined structures provide us with an unique opportunity to investigate dynamic processes induced by intermolecular interactions with specific orientations. The relative orientation of the two interacting molecules or atoms is defined by the complex structure. The effect of the orientation in the spin changing collisions glyoxal (S 1 ) + Ar → glyoxal (T 1 ) + Ar and acetylene (S 1 ) + Ar → acetylene (T) + Ar have been studied by measuring the intersystem crossing (ISC) rates of the glyoxal(S 1 ).Ar and acetylene(S 1 ).Ar complexes with different isomeric structures. Results show that there is a strong orientation dependence in the ISC of glyoxal(S 1 ) induced by interaction with the Ar atom: the Ar atom positioned in the molecular plane is much more effective than in the out-of-plane position in inducing the S 1 → T 1 transition of glyoxal. On the other hand, studies of acetylene(S 1 ).Ar complexes indicate that the Ar-induced ISC rates are nearly identical for the in-plane and out-of-plane positions. Orientation dependence in the collision induced vibrational relaxation process C 2 H 2 (S 1 , v i ) + Ar → C 2 H 2 (S 1 , v f i ) + Ar is also studied by measuring the vibrational predissociation rates of the acetylene(S 1 ).Ar complex isomers. The results indicate that collisions of C 2 H 2 (S 1 , v 3 = 3, 4) with Ar at two orthogonal orientations are equally effective in causing vibrational relaxation of C 2 H 2 . (orig.)

  1. New Drugs for CML

    Science.gov (United States)

    2007-02-01

    to a fulminant acute leukemic disorder in which patients die of bleeding and infection (1). Allogeneic bone marrow transplantation was the first...acetylenes were created in one step by the coupling of a propiolate anion and isocyanate. These acetylenes were then used as a precursor in the synthesis of...the furans. The furan synthesis was based on early research in the Austin laboratory, which was centered on the concept of adapting the 1,3-dipolar

  2. [Effects of organic and inorganic fertilizers on emission and sources of N2O in vegetable soils.

    Science.gov (United States)

    Lin, Wei; Ding, Jun Jun; Li, Yu Zhong; Xu, Chun Ying; Li, Qiao Zhen; Zheng, Qian; Zhuang, Shan

    2018-05-01

    To clarify the microbial pathway of the N 2 O production and consumption under different fertilizers and provide theoretical basis for the reduction of N 2 O emission and rational management of fertilization in vegetable soils, we examined dynamics of N 2 O flux and isotope signatures under different fertilizer treatments in the vegetable soils of Beijing, by setting up four treatments (organic-acetylene, organic-nonacetylene, inorganic-acetylene, inorganic-nonacetylene) and using the stable isotope technique of natural N 2 O abundance. The results showed that the cumulative N 2 O emission from organic-acetylene group, organic-nonacetylene group, inorganic-acetylene group and inorganic-nonacetylene group was (374±37), (283±34), (458±36), (355±41) g·m -2 in cabbage growing season, respectively. N 2 O fluxes were significantly lower in treatments with organic fertilizer than those with inorganic fertilizer and significantly higher in acetylene group than nonacetylene group. The degree of N 2 O reduction were similar in both fertilizer treatments, and higher nitrification was found in inorganic fertilizer than organic fertilizer treatments. Acetylene only inhibited partial nitrification and partial N 2 O reduction at the peak of N 2 O emission. When the emission was reduced, N 2 O reduction could be completely suppressed. Therefore, the inorganic fertilizer might trigger nitrification and promote higher N 2 O emission. The high concentration of N 2 O could withstand that acetylene to inhibite N 2 O reduction. Hence, using organic fertilizers instead of some inorganic ones could effectively reduce N 2 O emission in vegetable soils of Beijing. The N 2 O concentration threshold should be considered when we identify N 2 O source by acetylene inhibition method.

  3. Burn Injury Arise From Flying Balloon Toys

    Directory of Open Access Journals (Sweden)

    Yalcin Kulahci

    2007-08-01

    Full Text Available Many of peoples are faced minor or major burn injuries in their life. Even the most widespread burn cause is flame injuries, too different burn cause pointed out in literature like Acetylen burns. The cases which imply in literature, mostly causes from explosion of high pressure acetylene tube, metal oxygene patch flame or carbide lamp using from cave explorers. An interesting acetylene burn cause in Turkey was publised by the authors. This cases was to come into being from flying toy balloons flame. 80 person was injured from flying toy ballons flame in a meeting in 2002. Although this potential risks of acetylene, helium have not any of some risk. But helium was provided from other countries and have more price. The injuries which caused from acetylene burns like 1st -2nd degree burns. Consequently that was known helium is more avaliable for using in toy sector, and never cause burn injuries like this. [TAF Prev Med Bull. 2007; 6(4: 291-296

  4. Selectivity in catalytic alkyne cyclotrimerization over chromium(VI): kinetic evaluation using the characteristics of radioactive carbon-11 decay for nondisruptive ultrasensitive detection of adsorbed species

    International Nuclear Information System (INIS)

    Ferrieri, R.A.; Wolf, A.P.

    1984-01-01

    The application of carbon-11 to kinetic measurements of molecular sorption is reported using positron annihilation surface detection (PASD). The technique is nondisruptive to dynamic processes and has the sensitivity to detect 10 -8 of a monolayer. In studies of alkyne cyclomerization on silica-alumina-supported Cr(VI), a high selectivity toward p-xylene formation was observed when acetylene-propyne mixtures were cotrimerized at monolayer total alkyne coverages. This selectivity was enhanced to 84% p-xylene, as the partial acetylene coverage was reduced to 1.0% of a monolayer. Competitive sorption studies utilized PASD to measure the surface concentration of [ 11 C]-acetylene coupled with macroscopic sorption measurements of propyne. Surface displacement of sorbed acetylene by propyne was observed with subsequent readsorption. The kinetics of this displacement were evaluated by using PASD in pulse-flow studies with various acetylene and propyne coverages and were modeled to a calculation of the isomeric xylene distribution. A near-identical fit was obtained between experimental and modeled results. This strongly suggested that the observed selectivity for p-xylene formation was due to sorbate interactions resulting in a specific molecular ordering of the alkyne mixture on the catalyst surface

  5. Achievement report for fiscal 1981 on research under Sunshine Program. Basic research on plasma-aided coal gasification technology; 1981 nendo sushine keikaku kenkyu seika hokokusho. Sekitan no plasma gas ka gijutsu no kiso kenkyu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1982-03-01

    Researches are conducted for the development of a technology of producing useful gases such as acetylene, hydrogen, carbon monoxide, etc., from coal by the use of the high temperature and high-density energy of the plasma jet. In an experiment using a 100kW 3-port plasma-aided gasification unit, rapid quenching tests are conducted using hydrogen and helium, where the reaction furnace is changed, the specimen feed device is changed, and the plasma torch head is replaced by a high-power head. In a test of the coal specimen, it is found that rapid quenching exerts a great effect on the prevention of re-decomposition of the generated acetylene into hydrogen and carbon black and that a rise in the hydrogen partial pressure results in a great decrease in the quantity of acetylene generated. The said torch head replacement increases the rate of the coal specimen infiltrating into the plasma flame, which brings about an increase in the quantity of acetylene generated. It is found after all that the conventional acetylene yield of 34g/kWh increases to 59g/kWh in a rapid quenching test in which the specimen is dried Akabira coal and the plasma is an argon gas plasma containing 40% hydrogen. (NEDO)

  6. An Approach for Hydrogen Recycling in a Closed-loop Life Support Architecture to Increase Oxygen Recovery Beyond State-of-the-Art

    Science.gov (United States)

    Abney, Morgan B.; Miller, Lee; Greenwood, Zachary; Alvarez, Giraldo

    2014-01-01

    State-of-the-art atmosphere revitalization life support technology on the International Space Station is theoretically capable of recovering 50% of the oxygen from metabolic carbon dioxide via the Carbon Dioxide Reduction Assembly (CRA). When coupled with a Plasma Pyrolysis Assembly (PPA), oxygen recovery increases dramatically, thus drastically reducing the logistical challenges associated with oxygen resupply. The PPA decomposes methane to predominantly form hydrogen and acetylene. Because of the unstable nature of acetylene, a down-stream separation system is required to remove acetylene from the hydrogen stream before it is recycled to the CRA. A new closed-loop architecture that includes a PPA and downstream Hydrogen Purification Assembly (HyPA) is proposed and discussed. Additionally, initial results of separation material testing are reported.

  7. Diacetylene time-temperature indicators

    International Nuclear Information System (INIS)

    Patel, G.N.; Yee, K.C.

    1980-01-01

    An improved recording device is described, useful for measuring the integrated time-temperature or integrated radiation-dosage history of an article, comprising a substrate onto which an acetylenic compound, containing at least two conjugated c*c groups, in an inactive form, is deposited. The inactive form is capable of being converted by melt or solvent recrystallization to an active form, which undergoes 1,4-addition polymerization resulting in an irreversible, progressive color change. The color change produced at any given point in time represents an integrated time-temperature history of thermal annealing or integrated radiation-dosage history of exposure to actinic radiation to which an article has been exposed. Also described is a process for producing an inactive form of the acetylenic compound. A film and a fiber, made from the inactive form of an acetylenic compound are also described

  8. Structural and mechanical properties of amorphous carbon films deposited by the dual plasma technique

    Institute of Scientific and Technical Information of China (English)

    Yaohui Wang; Xu Zhang; Xianying Wu; Huixing Zhang; Xiaoji Zhang

    2008-01-01

    Direct current metal filtered cathodic vacuum are (FCVA) and acetylene gas (C2H2) were wielded to synthesize Ti-containing amorphous carbon films on Si (100). The influence of substrate bias voltage and acetylene gas on the microstructure and mechanical properties of the films were investigated. The results show that the phase of TiC in the (111) preferential crystallo-graphic orientation exists in the film, and rite main existing pattern of carbon is sp2. With increasing the acetylene flow rate, the con-tents of Ti and TiC phase of the film gradually reduce; however, the thickness of the film increases. When the substrate bias voltage reaches -600 V, the internal stress of the film reaches 1.6 GPa. The micro-hardness and elastic modulus of the film can reach 33.9 and 237.6 GPa, respectively, and the friction coefficient of the film is 0.25.

  9. Use of 15N in evaluating symbiotic N2 fixation of field-grown soybeans

    International Nuclear Information System (INIS)

    Ham, G.E.

    1978-01-01

    Various methods have been used to estimate N 2 fixation by legumes (i.e. Kjeldahl N and the acetylene-ethylene assay). Recently 'Asub(N)' values by the legume and a non-nodulating crop using 15 N-labelled N fertilizer were used to quantitatively estimate the amount of N 2 fixed by legume crops growing under field conditions. The objective of this research was to evaluate Kjeldahl N procedures, the acetylene-ethylene assay and the 'Asub(N)' technique as estimators of N 2 fixation by field-grown soybeans. The 'Asub(N)' value concept provided a reliable estimate of N 2 fixation by soybeans which agreed with acetylene-ethylene measurements made weekly and the values compared favourably with Kjeldahl N measurements. (author)

  10. Effects of specific inhibitors on anammox and denitrification in marine sediments.

    Science.gov (United States)

    Jensen, Marlene Mark; Thamdrup, Bo; Dalsgaard, Tage

    2007-05-01

    The effects of three metabolic inhibitors (acetylene, methanol, and allylthiourea [ATU]) on the pathways of N2 production were investigated by using short anoxic incubations of marine sediment with a 15N isotope technique. Acetylene inhibited ammonium oxidation through the anammox pathway as the oxidation rate decreased exponentially with increasing acetylene concentration; the rate decay constant was 0.10+/-0.02 microM-1, and there was 95% inhibition at approximately 30 microM. Nitrous oxide reduction, the final step of denitrification, was not sensitive to acetylene concentrations below 10 microM. However, nitrous oxide reduction was inhibited by higher concentrations, and the sensitivity was approximately one-half the sensitivity of anammox (decay constant, 0.049+/-0.004 microM-1; 95% inhibition at approximately 70 microM). Methanol specifically inhibited anammox with a decay constant of 0.79+/-0.12 mM-1, and thus 3 to 4 mM methanol was required for nearly complete inhibition. This level of methanol stimulated denitrification by approximately 50%. ATU did not have marked effects on the rates of anammox and denitrification. The profile of inhibitor effects on anammox agreed with the results of studies of the process in wastewater bioreactors, which confirmed the similarity between the anammox bacteria in bioreactors and natural environments. Acetylene and methanol can be used to separate anammox and denitrification, but the effects of these compounds on nitrification limits their use in studies of these processes in systems where nitrification is an important source of nitrate. The observed differential effects of acetylene and methanol on anammox and denitrification support our current understanding of the two main pathways of N2 production in marine sediments and the use of 15N isotope methods for their quantification.

  11. Nodulation of legumes, nitrogenase activity of roots and occurrence of nitrogen-fixing Azospirillum spp. In representative soils of central Amazonia

    Energy Technology Data Exchange (ETDEWEB)

    Sylvester-Bradley, R; De Oliverira, L A; De Podesta Filho, J A; John, T V

    1980-12-01

    Leguminosae do not predominate in the Brazilian Amazon rain forest, although they are among the five best represented families. Plant roots from various soils were examined for the presence of nodules, acetylene-reducing activity and N/sub 2/-fixing Azospirillum spp. Abundant nodulation was found in black earth (''terra preta dos indios'') and in one case on sandy soil under campinarana vegetation along a tributary of the upper Rio Negro. In sandy latosol some nodules occurred in secondary forest and fewer in primary forest. Legumes in disturbed clayey or sandy latosol showed more frequent nodulation. Primary forest on alluvial (''varzea'') soil, and in Bahia coastal rain forest on sandy latosol and Erythrina glauca used for shading cacao plantations were abundantly nodulated. Acetylene reduction assays showed no, or very little, nitrogenase activity of roots from primary or secondary forest on clayey latosol near Manaus. Nodulated roots from secondary forest on sandy latosol showed acetylene-reducing activity. High rates of acetylene reduction were observed in nodulated roots of primary forest on alluvial ''varzea'' soil. Root samples showed ethylene absorption in controls without acetylene which might interfere with the results of acetylene reduction tests. The incidence of Azospirillum was also higher in black earth than the other soils examined, and in soils with higher pH. The hypothesis that Azospirillum is associated with Trema micantha roots was refuted. Roots and soils collected under cultivated grasses showed a higher incidence of Azospirillum when fertilized with phosphorus and lime. Results indicate that nitrogen fixation did occur in association with roots in some soils, but not with roots of primary or secondary forest on clayey latosol in the vicinity of Manaus, which is the most common soil in Central Amazonia. The possible reasons for this are discussed.

  12. Effect of electron beam radiation on the structure and mechanical properties of ultra high molecular weight polyethylene fibers

    International Nuclear Information System (INIS)

    Li Shujun; Sun Weijun; Liu Xiuju; Gao Yongzhong; Li Huisheng

    1998-01-01

    Ultra high molecular weight polyethylene fibers have been crosslinked by electron beam. The structure and mechanical properties of them have been investigated in different irradiation atmospheres. The obtained results show that the gel content and crosslinking density increase with the increase of dose, the swelling ratio and average molecular weight of crosslinked net decrease with the increase of dose, the tensile strength and failure elongation decrease with the increase of dose, the tensile modulus increases with the increase of dose. When the samples are irradiated in air, vacuum and acetylene atmospheres, the effect of irradiation in acetylene atmosphere is best

  13. Synthesis of samarium, europium and ytterbium acetylenides

    International Nuclear Information System (INIS)

    Bochkarev, M.N.; Fedorova, E.A.; Glushkova, N.V.; Protchenko, A.V.; Druzhkov , O.N.; Khorshev, S.Ya.

    1995-01-01

    Ethynyl complexes of samarium, europium and ytterbium were prepared by interaction of naphthalinides of metals with acetylene in tetrahydrofuran. The compounds are isolated in the form of dark-coloured pyrophore powders. Data of magnetic measurements suggest that in the course of the reaction Sm(2) is oxidized completely to Sm(3), Yb(2) transforms into Yb(3) partially, whereas europium preserves its initial bivalent state. Hydrolysis of the compounds prepared provides acetylene, ethylene, ethane and hydrogen which indicates the presence of acethylenide Ln 2 C 2 and hydride LnH groupings (Ln = Sm, Eu, Yb). 9 refs., 2 tabs

  14. Growth of highly oriented carbon nanotubes by plasma-enhanced hot filament chemical vapor deposition

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Z.P.; Xu, J.W.; Ren, Z.F.; Wang, J.H. [Materials Synthesis Laboratory, Departments of Physics and Chemistry, and Center for Advanced Photonic and Electronic Materials (CAPEM), State University of New York at Buffalo, Buffalo, New York 14260 (United States); Siegal, M.P.; Provencio, P.N. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1421 (United States)

    1998-12-01

    Highly oriented, multiwalled carbon nanotubes were grown on polished polycrystalline and single crystal nickel substrates by plasma enhanced hot filament chemical vapor deposition at temperatures below 666 {degree}C. The carbon nanotubes range from 10 to 500 nm in diameter and 0.1 to 50 {mu}m in length depending on growth conditions. Acetylene is used as the carbon source for the growth of the carbon nanotubes and ammonia is used for dilution gas and catalysis. The plasma intensity, acetylene to ammonia gas ratio, and their flow rates, etc. affect the diameters and uniformity of the carbon nanotubes. {copyright} {ital 1998 American Institute of Physics.}

  15. Multifaceted Strategy for the Synthesis of Diverse 2,2'-Bithiophene Derivatives

    Directory of Open Access Journals (Sweden)

    Stanisław Krompiec

    2015-03-01

    Full Text Available New catalytically or high pressure activated reactions and routes, including coupling, double bond migration in allylic systems, and various types of cycloaddition and dihydroamination have been used for the synthesis of novel bithiophene derivatives. Thanks to the abovementioned reactions and routes combined with non-catalytic ones, new acetylene, butadiyne, isoxazole, 1,2,3-triazole, pyrrole, benzene, and fluoranthene derivatives with one, two or six bithiophenyl moieties have been obtained. Basic sources of crucial substrates which include bithiophene motif for catalytic reactions were 2,2'-bithiophene, gaseous acetylene and 1,3-butadiyne.

  16. Photoelectron Diffraction Imaging for C2H2 and C2H4 Chemisorbed on Si(100) Reveals a New Bonding Configuration

    International Nuclear Information System (INIS)

    Xu, S. H.; Keeffe, M.; Yang, Y.; Chen, C.; Yu, M.; Lapeyre, G. J.; Rotenberg, E.; Denlinger, J.; Yates, J. T. Jr.

    2000-01-01

    A new adsorption site for adsorbed acetylene on Si(100) is observed by photoelectron imaging based on the holographic principle. The diffraction effects in the carbon 1s angle-resolved photoemission are inverted (including the small-cone method) to obtain an image of the atom's neighboring carbon. The chemisorbed acetylene molecule is bonded to four silicon surface atoms. In contrast to the C 2 H 2 case, the image for adsorbed C 2 H 4 shows it bonded to two Si surface atoms. (c) 2000 The American Physical Society

  17. Kinetics of Hydrocarbon formation in a-C:H film deposition plasmas

    International Nuclear Information System (INIS)

    De la Cal, E.; Tabares, F.L.

    1993-01-01

    The formation of C 2 and C 3 hydrocarbons during the PACVD of a-C-H films from admixtures of methane with H 2 and He has been investigated by mass spectrometry under several deposition condition. The time evolution of the observed species indicates that the formation mechanism of ethylene and acetylene are sensitive to the conditions of the wall during the growing of the film. Acetylene are sensitive to the conditions of the wall during the growing of the carburized metal. (Author)

  18. Procedure for coating articles with pyrolytic carbon

    International Nuclear Information System (INIS)

    Adams, C.C.; Allen, C.L.; Besenbruch, G.E.A.

    1976-01-01

    A method to coat articles with pyrolytic carbon is described which is particularly suitable for small nuclear fuel particles as one obtains a very homogeneous layer. The pyrolytic carbon is produced according to the invention by decomposing a hydrocarbon gas mixture composed of an inert gas share (20-65 Vol%) and a mixture of acetylene and propylene. It is favourable to have the hydrocarbon mixture contain between 50 and 55 Vol% acetylene. Variations on the known procedure are given. The coating of spherical thorium dioxide particles is mentioned as an example. (UWI) [de

  19. Synthesis and study of conjugated polymers containing Di- or Triphenylamine

    Energy Technology Data Exchange (ETDEWEB)

    Sukwattanasinitt, M.

    1996-06-21

    This thesis consists of two separate parts. The first part addresses the synthesis and study of conjugated polymers containing di- or triphenylamine. Two types of polymers: linear polymers and dendrimers, were synthesized. The polymers were characterized by NMR, IR, UV, GPC, TGA and DSC. Electronic and optical properties of the polymers were studied through the conductivity measurements and excitation- emission spectra. the second part of this thesis deals with a reaction of electron-rich acetylenes with TCNE. The discovery of the reaction from charge transfer complex studies and the investigation of this reaction on various electron-rich acetylenes are presented.

  20. Direct Spectroscopy in Hollow Optical with Fiber-Based Optical Frequency Combs

    Science.gov (United States)

    2015-07-09

    scheme is that the generation of carrier-envelope offset frequency f0 can be avoided, which reduces the system complexity . However, a high performance RF...Peterson, "Saturated absorption in acetylene and hydrogen cyanide in hollow-core photonic bandgap fibers," Opt. Express 13, 10475-10482 (2005). 56. C

  1. Nepheliosyne B, a New Polyacetylenic Acid from the New Caledonian Marine Sponge Niphates sp.

    Directory of Open Access Journals (Sweden)

    Patrick Auberger

    2013-06-01

    Full Text Available A new C47 polyoxygenated acetylenic acid, nepheliosyne B (2, along with the previously described nepheliosyne A (1, have been isolated from the New Caledonian marine sponge Niphates sp. Their structures have been elucidated on the basis of extensive spectroscopic analyses. These metabolites exhibited a moderate cytotoxicity against K562, U266, SKM1, and Kasumi cancer cell lines.

  2. Mild copper-catalyzed trifluoromethylation of terminal alkynes using an electrophilic trifluoromethylating reagent

    KAUST Repository

    Weng, Zhiqiang

    2012-03-01

    A catalytic process for trifluoromethylation of terminal alkynes with Togni\\'s reagent has been developed, affording trifluoromethylated acetylenes in good to excellent yields. The reaction is conducted at room temperature and exhibits tolerance to a range of functional groups. © 2012 Elsevier Ltd. All rights reserved.

  3. Fabrication and evaluation of polymeric early-warning fire-alarm devices. [combustion products

    Science.gov (United States)

    Senturia, S. D.

    1975-01-01

    The electrical resistivities were investigated of some polymers known to be enhanced by the presence of certain gases. This was done to make a device capable of providing early warning to fire through its response with the gases produced in the early phases of combustion. Eight polymers were investigated: poly(phenyl acetylene), poly(p-aminophenyl acetylene), poly(p-nitrophenyl acetylene), poly(p-formamidophenyl acetylene), poly(ethynyl ferrocene), poly(ethynyl carborane), poly(ethynyl pyridine), and the polymer made from 1,2,3,6 tetramethyl pyridazine. A total of 40 usable thin-film sandwich devices and a total of 70 usable interdigitated-electrode lock-and-key devices were fabricated. The sandwich devices were used for measurements of contact linearity, polymer conductivity, and polymer dielectric constant. The lock-and-key devices were used to determine the response of the polymers to a spectrum of gases that included ammonia, carbon nonoxide, carbon dioxide, sulfur dioxide, ethylene, acrolein, water vapor, and normal laboratory air. Strongest responses were to water vapor, ammonia, and acrolein, and depending on the polymer, weaker responses to carbon dioxide, sulfur dioxide, and carbon monoxide were observed. A quantitative theory of device operation, capable of accounting for observed device leakage current and sensitivity, was developed. A prototype detection/alarm system was designed and built for use in demonstrating sensor performance.

  4. Preparation and crystal structures of low-valent zirconocene complexes containing tetramethyl(phenyl) cyclopentadienyl ligands

    Czech Academy of Sciences Publication Activity Database

    Horáček, Michal; Pinkas, Jiří; Kubišta, Jiří; Císařová, I.; Gyepes, R.; Štěpnička, P.

    2007-01-01

    Roč. 72, 5-6 (2007), s. 679-696 ISSN 0010-0765 R&D Projects: GA MŠk(CZ) LC06070 Institutional research plan: CEZ:AV0Z40400503 Keywords : metallocenes * zirconocenes * bis(trimethylsilyl)acetylene * low-valent zirconium complexes Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 0.879, year: 2007

  5. 2317-IJBCS-Article-Racheal Adebola A

    African Journals Online (AJOL)

    hp

    contaminated with heavy metals gotten from raw materials, manufacturing and packaging processes. It is therefore crucial to .... 4.5 or more cups of fruits and vegetables each day. Milk is an ideal ... fuel clean Air-Acetylene flame was used. The.

  6. Calcium carbide (CaC2): Effect on fruit set and yield of mango ...

    African Journals Online (AJOL)

    Reviewer

    contains nitrogen in both the ammonium and nitrate form, less subject to ... soil reacts with soil water to produce calcium ion and acetylene (C2H2). ..... nitrification inhibitors on methane and nitrous oxide fluxes in irrigated corn. pp. 278-289.

  7. Investigation of the immobilisation/mobilisation of nickel, copper ...

    African Journals Online (AJOL)

    DRINIE

    nitrate, manganese hydroxides, iron hydroxides, sulphate and carbon dioxide). ... standard solution contained (g·l-1 dH2O): ferrous ammonium sulphate, 39.21; ferric ... (AAS) with a nitrous oxide-acetylene flame, to minimise chemical interferences, was ... The synthetic refuse used facilitated the production of volatile fatty ...

  8. Preparation of Pt–Ru bimetallic catalyst supported on carbon

    Indian Academy of Sciences (India)

    The template carbonization of polyphenyl acetylene yields hollow, uniform cylindrical carbon nanotubes with outer diameter almost equal to pore diameter of the template used. High resolution transmission electron microscopic investigation reveals that Pt–Ru nanoparticles are highly dispersed inside the tube with an ...

  9. Gas phase pulse radiolysis

    International Nuclear Information System (INIS)

    Jonah, C.D.; Andong Liu; Mulac, W.A.

    1987-01-01

    Gas phase pulse radiolysis, a technique which can be used to study many different phenomena in chemistry and physics, is discussed. As a source of small radicals, pulse radiolysis is important to the field of chemistry, particularly to combustion and atmospheric kinetics. The reactions of 1,3-butadiene, allene, ethylene and acetylene with OH are presented. 52 refs., 1 fig., 1 tab

  10. Absorption and stimulated emission between the electronic states of C and C_2 radicals in an expanding thermal plasma

    NARCIS (Netherlands)

    Otorbaev, D.K.; Sanden, van de M.C.M.; Buuron, A.J.M.; Schram, D.C.

    1995-01-01

    Using the method of reabsorption the absolute densities of argon, atomic and molecular carbon are determined during the deposition of amorphous hydrogenated (diamond-like) carbon coatings by an expanding thermal are plasma. Depending on the gas mixture argon/methane or argon/acetylene and the manner

  11. Influence of osmotic and metal stresses on nitrogenase activity of ...

    African Journals Online (AJOL)

    Samples were collected from paddy fields in Corum-Turk.ye. Nitrogen-free BG-11 medium was used for isolation of nitrogen fixing cyanobacteria. Acetylene reduction technique was used to determine the effects of different chemical agents on the nitrogenase activities of the cyanobacteria, which were identified at the genus ...

  12. Optimization, yield studies and morphology of WO3 nano-wires synthesized by laser pyrolysis in C2H2 and O2 ambients—validation of a new growth mechanism

    CSIR Research Space (South Africa)

    Mwakikunga, BW

    2008-10-01

    Full Text Available Laser pyrolysis has been used to synthesize WO3 nanostructures. Spherical nano-particles were obtained when acetylene was used to carry the precursor droplet, whereas thin films were obtained at high flow-rates of oxygen carrier gas. In both...

  13. Forthcoming Articles

    Indian Academy of Sciences (India)

    NPadmaja

    2018-05-03

    May 3, 2018 ... bridged-atom in the formation of polysubstituted pyridines via. Hetero-Diels-Alder reaction of isotellurazoles with acetylenic dienophiles: A molecular electron density study abdo benallou abdo_benallou@yahoo.fr. Universite Chouaib. Doukkali safi. Morocco. 02 Apr. 34. JULY Spl. Issue-. MTIC. JCSC-D-18-.

  14. SHORT COMMUNICATION IMPACT OF ENVIRONMENTAL ...

    African Journals Online (AJOL)

    Preferred Customer

    This study evaluated the levels of cadmium, lead, copper and zinc in the ... analysis showed significant correlation (p < 0.01) between the metal levels in .... Atomic Absorption Spectrophotometer (UNICAM, UK) using air-acetylene flame. .... exceeded the 20 mg/kg recommended by Food Stuff, Cosmetics and Disinfectant Act.

  15. Kompatibilisierung von Elastomerverschnitten durch Kautschukadditive mit maßgeschneiderten Oberflächeneigenschaften

    NARCIS (Netherlands)

    Tiwari, M.; Datta, Rabin; Guo, R.; Talma, Auke; van Ooij, W.J.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2014-01-01

    Gummi ist ein herausforderndes Material, dessen Funktionalität stark von der Affinität seiner unterschiedlichen Bestand­teile und seiner Morphologie abhängt. Ein Weg, Polarität und Chemie der Füllstoffoberfläche maßzuschneidern, ist die Plasmabeschichtung. Werden Acetylen, Thiophen oder Pyrrol als

  16. Overcoming incompatibility in elastomer blends by rubber additives with tailored surface properties

    NARCIS (Netherlands)

    Tiwari, M.; Datta, Rabin; Guo, R.; Talma, Auke; van Ooij, W.J.; Dierkes, Wilma K.; Noordermeer, Jacobus W.M.

    2014-01-01

    Rubber is a challenging composite material, whose functionality strongly depends on the affinity of the different materials in the composite, and its morphology. One way to tailor polarity and chemistry of the filler surface is plasma coating. When using acetylene, thiophene, or pyrrole as monomers,

  17. Overcoming Incompatibility Problems in Elastomer Blends by Tailored Surface Properties of Rubber Additives

    NARCIS (Netherlands)

    Dierkes, Wilma K.; Tiwari, M.; Guo, R.; Datta, Rabin; Talma, Auke; Noordermeer, Jacobus W.M.; van Ooij, W.J.

    2013-01-01

    Rubber is a challenging composite material, whose functionality strongly depends on the affinity of the different materials in the composite and its morphology. One way to tailor polarity and chemistry of the filler surface is plasma coating. When using acetylene, thiophene, or pyrrole as monomers,

  18. Conclusion; Zaklyuchenie

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, V I

    1961-07-01

    In this chapter of book are present conclusions about work done by author, in particular that he found comparatively simple and available ways of synthesis of glycerin of acetylene line and glycerin of ethylen line which before was unknown or almost unknown in the chemical literature.

  19. Introduction; Vvedenie

    Energy Technology Data Exchange (ETDEWEB)

    Nikitin, V I

    1961-07-01

    Introduction describes the present book. Its includes seven chapters. First four from them touch with glycerin of acetylene line-their receiving, studying their oxidation reactions, transformations under the influence of dehydrating methods. Last three chapters dedicated to glycerin of ethylen line-synthesis, their cyclization into substituted dihydropyran.

  20. Download this PDF file

    African Journals Online (AJOL)

    DR. AMINU

    Purity of our environment such as air, water and soil are of great .... Varian 1200 with air acetylene flame (Jimoh and. Mohammad .... translocation of iron in the plant (Asia et al 2007). ... to the natural background concentration of iron in the.

  1. Controlled Synthesis of Carbon-Encapsulated Copper Nanostructures by Using Smectite Clays as Nanotemplates

    NARCIS (Netherlands)

    Tsoufis, Theodoros; Colomer, Jean-Francois; Maccallini, Enrico; Jankovic, Lubos; Rudolf, Petra; Gournis, Dimitrios; Jankovič, Lubos

    Rhomboidal and spherical metallic-copper nanostructures were encapsulated within well-formed graphitic shells by using a simple chemical method that involved the catalytic decomposition of acetylene over a copper catalyst that was supported on different smectite clays surfaces by ion-exchange. These

  2. Military Wastes-to-Energy Applications,

    Science.gov (United States)

    1980-11-01

    6 Residual) and Used Oil ( Automotive Crankcase Drainings) .......... ........................ 109 60 Properties of Coal: Bituminous, Subbituminous...facilities Physical/Chemical e Biomass removal from forest land may upset the Environment natural balance of terrestrial, aquatic, and atmospheric...ripout wastes (asbestos), sand- blasting wasts (organotin), and welding wastes (acetylene sludge); * Miscellaneous aircraft repair wastes -- brake

  3. Thermodynamic analysis of steam reforming and oxidative steam reforming of propane and butane for hydrogen production

    DEFF Research Database (Denmark)

    Cui, Xiaoti; Kær, Søren Knudsen

    2018-01-01

    /C) of 0.5–5 and O2/HC (hydrocarbon) ratio of 0–2.4. The simulations for the cracking and POX processes showed that olefins and acetylene can be easily generated through the cracking reactions and can be removed by adding an appropriate amount of oxygen. For SR and OSR of propane and butane, predicted...

  4. Trace gas absorption spectroscopy using laser difference-frequency spectrometer for environmental application

    Science.gov (United States)

    Chen, W.; Cazier, F.; Boucher, D.; Tittel, F. K.; Davies, P. B.

    2001-01-01

    A widely tunable infrared spectrometer based on difference frequency generation (DFG) has been developed for organic trace gas detection by laser absorption spectroscopy. On-line measurements of concentration of various hydrocarbons, such as acetylene, benzene, and ethylene, were investigated using high-resolution DFG trace gas spectroscopy for highly sensitive detection.

  5. Proton-transfer doping of polyacetylene

    Energy Technology Data Exchange (ETDEWEB)

    Tolbert, L.M.; Schomaker, J.A. (School of Chemistry and Biochemistry, Georgia Inst. of Tech., Atlanta (USA))

    1991-04-30

    Exhaustive deprotonation of films of poly(acetylene-co-1,3-butadiene) (PAB) fails to produce a conductive film. In contrast, deprotonation of segmented polyacetylene (SPA) produces a conductive material with similar characteristics to n-doped polyacetylene. Thus the feasibility of a proton-transfer approach to doping of polyacetylene has been demonstrated. (orig.).

  6. The Synthesis of cis- and trans-Fused Bicyclic Sugar Amino Acids

    NARCIS (Netherlands)

    Risseeuw, Martijn D.P.; Grotenbreg, Gijsbert M.; Witte, Martin D.; Tuin, Adriaan W.; Leeuwenburgh, Michiel A.; Marel, Gijsbert A. van der; Overkleeft, Herman S.; Overhand, Mark

    2006-01-01

    Four isomeric bicyclic sugar amino acids (SAAs) were prepared from an α-acetylenic-C-glucoside by employing a Petasis olefination and a ring-closing metathesis (RCM) as key steps. The applicability of the resulting SAAs in solid-phase peptide synthesis was demonstrated by the synthesis of a

  7. New uranium compounds preparation and use as catalyst for hydrogenation of non-saturated organic compounds

    International Nuclear Information System (INIS)

    Arnaudet, L.; Folcher, G.

    1985-01-01

    Preparation of new organic uranium compounds and their use as catalysts for hydrogenation of non-saturated organic compounds are described. These compounds include Uranium III, a cyclopentadienic group, an alkyl group and an acetylenic derivative C 6 H 5 C triple bonds CR fixed by a π bond. Catalysts can be prepared with depleted uanium for hydrogenation of olefins for example [fr

  8. KAROTENOID PADA ALGAE: KAJIAN TENTANG BIOSINTESIS, DISTRIBUSI SERTA FUNGSI KAROTENOID

    OpenAIRE

    Merdekawati, Windu; Karwur, Ferry F.; Susanto, A. B.

    2017-01-01

    ABSTRAK   Karotenoid terdistribusi pada archaea, bakteri, jamur, tumbuhan, hewan serta algae. Karotenoid dihasilkan dari komponen isopentenyl pyrophosphate (IPP) yang mengalami proses secara bertahap untuk membentuk beragam jenis karotenoid. Terdapat dua kelompok karotenoid yaitu karoten dan xantofil dengan berbagai jenis turunannya. Struktur kimia pada karotenoid algae yaitu allene, acetylene serta acetylated carotenoids. Algae mempunyai karotenoid spesifik yang menarik untuk dipe...

  9. Fatty acids labelled with iodine 123 or 131 in. omega. position; myocardial evolution

    Energy Technology Data Exchange (ETDEWEB)

    Riche, F.; Vidal, M. (Grenoble-1 Univ., 38 (France)); Mathieu, J.P.; Busquet, G.; Comet, M. (Grenoble-1 Univ., 38 - La Tronche (France)); Coornaert, S.; Bardy, A. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Office des Rayonnements Ionisants); Godart, J. (Grenoble-1 Univ., 38 (France). Inst. des Sciences Nucleaires)

    A simple and rapid method of labelling a number of saturated acetylenic and Z or E ethylenic acids has been developed. The fatty acids are labelled with /sup 123/I- or /sup 131/I- in the ..omega.. position by isotopic exchange labelled NaI in acetone. Myocardial metabolism was studied by injecting the labelled fatty acids into mice.

  10. Quantifying methane emission from fugitive sources by combining tracer release and downwind measurements – A sensitivity analysis based on multiple field surveys

    DEFF Research Database (Denmark)

    Mønster, Jacob; Samuelsson, Jerker; Kjeldsen, Peter

    2014-01-01

    Using a dual species methane/acetylene instrument based on cavity ring down spectroscopy (CRDS), the dynamic plume tracer dispersion method for quantifying the emission rate of methane was successfully tested in four measurement campaigns: (1) controlled methane and trace gas release with differe...

  11. Petrochemistry on process, goods and market

    International Nuclear Information System (INIS)

    Kim, Jong Deuk; Kim, Hwa Yong; Seo, Gon

    1995-12-01

    This book indicates petrochemistry with summary, importance and economic consideration of organic chemistry industry, synthetic gas ; ammonia, urea, nitric acid, oxo chemicals, phosgene, formic acid and neo-acids, methane ; hydrogen cyanide, HCN and chlorinated methanes, acetylene ; vinyl acetate, neoprene, acrylates and Reppe chemicals, ethylene ; polyethylene and ethanol, propylene ; allyl chloride and isoprene, hydrocarbon: butadiene, isobutylene, aromatic hydrocarbon and other petrochemistry productions.

  12. Stress in tungsten carbide-diamond like carbon multilayer coatings

    NARCIS (Netherlands)

    Pujada, B.R.; Tichelaar, F.D.; Janssen, G.C.A.M.

    2007-01-01

    Tungsten carbide-diamond like carbon (WC-DLC) multilayer coatings have been prepared by sputter deposition from a tungsten-carbide target and periodic switching on and off of the reactive acetylene gas flow. The stress in the resulting WC-DLC multilayers has been studied by substrate curvature.

  13. Low-pressure degenerate four-wave mixing spectroscopy with flam atomization

    International Nuclear Information System (INIS)

    Nolan, T.G.; Koutny, L.B.; Blazewicz, P.R.; Whitten, W.B.; Ramsey, J.M.

    1988-01-01

    A combination of degenerate four-wave mixing spectroscopy and a low-pressure sampling technique has been studied for isotopic analysis in an air-acetylene flame. Hyperfine spectra of D lines of sodium and several mixtures of lithium isotopes obtained in this way are presented

  14. Journal of Chemical Sciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    Home; Journals; Journal of Chemical Sciences. CHANDRASEKAR PRAVEEN. Articles written in Journal of Chemical Sciences. Volume 128 Issue 1 January 2016 pp 73-83 Regular Articles. Cycloisomerization of acetylenic oximes and hydrazones under gold catalysis: Synthesis and cytotoxic evaluation of isoxazoles and ...

  15. Carbolanthanation of substituted alkynes

    International Nuclear Information System (INIS)

    Kalinin, V.N.; Kazimirchuk, E.I.; Vitt, S.V.; Khandozhko, V.N.; Beletskaya, I.P.

    1993-01-01

    Using the reaction between CH 3 YbI and substituted alkynes as an example, agents can enter into carbolanthanation reaction via transfer of a methyl group to carbon atom of acetylene bond with the production of a new olefin carbanion. 5 refs.; 1 fig.; 3 tabs

  16. FeCl3- and GaCl3-Catalyzed Dehydrative Coupling Reaction of Chromone-Derived Morita-Baylis-Hillman Alcohols with Terminal Alkynes%FeCl3- and GaCl3-Catalyzed Dehydrative Coupling Reaction of Chromone-Derived Morita-Baylis-Hillman Alcohols with Terminal Alkynes

    Institute of Scientific and Technical Information of China (English)

    武陈; 曾皓; 刘哲; 刘利; 王东; 陈拥军

    2011-01-01

    FeCl3- and GaCl3-catalyzed dehydrative coupling reactions of chromone-derived Morita-Baylis-Hillman (MBH) alcohols with terminal alkynes were developed. The reactions provided exclusively a-regioselective and acetylene-substituted products in good yields.

  17. Zinc mediated activation of terminal alkynes: stereoselective synthesis of alkynyl glycosides.

    Science.gov (United States)

    Tatina, Madhu Babu; Kusunuru, Anil Kumar; Yousuf, Syed Khalid; Mukherjee, Debaraj

    2014-10-28

    Zinc mediated alkynylation reaction was studied for the preparation of C-glycosides from unactivated alkynes. Different glycosyl donors such as glycals and anomeric acetates were tested towards an alkynyl zinc reagent obtained from alkynes using zinc dust and ethyl bromoacetate as an additive. The method provides simple, mild and stereoselective access to alkynyl glycosides both from aromatic and aliphatic acetylenes.

  18. Hydrophosphorylation of alkynes with phosphinous acids

    International Nuclear Information System (INIS)

    Nifant'ev, E.E.; Solovetskaya, L.A.; Magdeeva, R.K.

    1986-01-01

    A feature of the homolytic hydrophosphorylation of alkynes, as compared with alkenes, is more ready addition of phosphinous acids in presence of benzoyl peroxides. A difference was found in the hydrophosphorylation of acetylenes with dibutylphosphinous acid and with diarylphosphinous acids: the latter tend to form diaddition products

  19. Calcium carbide (CaC2): Effect on fruit set and yield of mango ...

    African Journals Online (AJOL)

    Application of slow release calcium carbide (CaC2) to the soil are thought to improve plant growth and yield through the generation of acetylene, which inhibits nitrification, thereby reducing nitrogen losses which may be converted to physiologically significant concentrations of the plant growth regulator ethylene. The effects ...

  20. The formation of ethane from carbon dioxide under cold plasma

    International Nuclear Information System (INIS)

    Zhang Xiuling; Zhang Lin; Dai Bin; Gong Weimin; Liu Changhou

    2001-01-01

    Pulsed-corona plasma has been used as a new method for ethane dehydrogenation at low temperature and normal pressure using carbon dioxide as an oxidant. The effect of carbon dioxide content in the feed, power input, and flow rate of the reactants on the ethane dehydrogenation has been investigated. The experimental results show that the conversion of ethane increases with the increasing in the amount of carbon dioxide in the feed. The yield of ethylene and acetylene decreases with the increasing in the yield of carbon monoxide, indicating that the increased carbon dioxide leads to the part of ethylene and acetylene being oxidized to carbon monoxide. Power input is primarily an electrical parameter in pulsed-corona plasma, which plays an important role in reactant conversion and product formation. When the power input reaches 16 W, ethane conversion is 41.0% and carbon dioxide conversion is 26.3%. The total yield of ethylene and acetylene is 15.6%. The reduced flow rate of feed improves the conversion of ethane, carbon dioxide and the yield of acetylene, and induces carbon deposit as well

  1. High Temperature Advanced Structural Composites. Volume 2. Ceramic Matrix Composites, Fiber Processing and Properties, and Interfaces

    Science.gov (United States)

    1993-04-02

    furfural . toughness and a pseudoplasticity. the latter of treated to a higher temperature. The mamx or acetylenic resins provide simple processing...crystalline by TU/SAD and has an effective surface area of 250 m /go based on BET measurments with N2 adsorption . This solid crystallizes to high purity

  2. Synthesis and characterization of germa[n]pericyclynes.

    Science.gov (United States)

    Tanimoto, Hiroki; Nagao, Tomohiko; Nishiyama, Yasuhiro; Morimoto, Tsumoru; Iseda, Fumiyasu; Nagato, Yuko; Suzuka, Toshimasa; Tsutsumi, Ken; Kakiuchi, Kiyomi

    2014-06-14

    The synthesis and characterization of novel pericyclynes comprising germanium atoms and acetylenes, germa[n]pericyclynes, are described. The prepared germa[4]-, [6]-, and [8]pericyclynes were compared by (13)C NMR spectroscopy, X-ray crystallography, cyclic voltammetry, UV-visible spectroscopy, fluorescence emission spectroscopy, Raman spectroscopy, and density functional theory calculation analyses.

  3. Diversity and antifungal activity of endophytic diazotrophic bacteria colonizing sugarcane in Egypt

    Science.gov (United States)

    The price of nitrogen continues to increase and is a major input in sugarcane production. Sugarcane grown in Egypt was screened for the presence of nitrogen-fixing bacteria. Nitrogen-free medium LGI-P was used to isolate bacteria from cane stalks. Among the 52 isolates subjected to acetylene redu...

  4. Geminal phosphorus/aluminum-based frustrated Lewis pairs: C-H versus C≡C activation and CO2 fixation

    NARCIS (Netherlands)

    Appelt, C.; Westenberg, H.; Bertini, F.; Ehlers, A.W.; Slootweg, J.C.; Lammertsma, K.; Uhl, W.

    2011-01-01

    Catch it! Geminal phosphorus/aluminum-based frustrated Lewis pairs (FLPs) are easily obtained by hydroalumination of alkynylphosphines. These FLPs can activate terminal acetylenes by two competitive pathways, which were analyzed by DFT calculations, and they can bind carbon dioxide reversibly.

  5. Synthesis of leukotrienes labelled with deuterium: [11,12,14,15-2H4]-LTA4, -LTC4, -LTD4 and -LTE4

    International Nuclear Information System (INIS)

    Lellouche, J.P.; Aubert, F.; Noel, J.P.; Boullais, C.; Beaucourt, J.P.

    1989-01-01

    Semi-hydrogenation by D 2 gas on Lindlar catalyst of an acetylenic precursor led to [11,12,14,15- 2 H 4 ]-LTA 4 methyl ester. Nucleophilic opening of the epoxide ring by amino thioacids accorded, after saponification, the corresponding deuterated peptidoleukotrienes LTC 4 , LTD 4 and LTE 4 . (author)

  6. Interstitial Hardening of Stainless Steel for Enhanced Corrosion Resistance for Naval Applications

    Science.gov (United States)

    2017-03-01

    smoothness of the final polish. All of the specimens were treated with the same acetylene-based carburizing recipe : 16 hat 450 oc in 0.05 liters/minute...novel low temperature (< 500 Celsius) interstitial hardening process for stainless steels for impellers, fasteners and other marine items. Although

  7. Influence of External Nitrogen on Nitrogenase Enzyme Activity and Auxin Production in Herbaspirillum seropedicae (Z78).

    Science.gov (United States)

    Yin, Tan Tzy; Pin, Ui Li; Ghazali, Amir Hamzah Ahmad

    2015-04-01

    The production of nitrogenase enzyme and auxins by free living diazotrophs has the potential to influence the growth of host plants. In this study, diazotrophs were grown in the presence of various concentrations of nitogen (N) to determine the optimal concentration of N for microbial growth stimulation, promotion of gaseous N (N2) fixation, and phytohormone production. Therefore, we investigate whether different levels of N supplied to Herbaspirillum seropedicae (Z78) have significant effects on nitrogenase activity and auxin production. The highest nitrogenase activity and the lowest auxin production of H. seropedicae (Z78) were both recorded at 0 gL(-1) of NH4Cl. Higher levels of external N caused a significant decrease in the nitrogenase activity and an increased production of auxins. In a subsequent test, two different inoculum sizes of Z78 (10(6) and 10(12) cfu/ml) were used to study the effect of different percentages of acetylene on nitrogenase activity of the inoculum via the acetylene reduction assay (ARA). The results showed that the optimal amount of acetylene required for nitrogenase enzyme activity was 5% for the 10(6) cfu/ml inoculum, whereas the higher inoculum size (10(12) cfu/ml) required at least 10% of acetylene for optimal nitrogenase activity. These findings provide a clearer understanding of the effects of N levels on diazotrophic nitrogenase activity and auxin production, which are important factors influencing plant growth.

  8. Reduction of nitro groups by ynamines; synthesis and x-ray crystal structure of n,n-diethyl-3,3a-dihydro-3-methylbenzofuro[3,2-c]isoxazole-3-carboxamide

    NARCIS (Netherlands)

    de Wit, A.D.; Trompenaars, W.P.; Reinhoudt, David; Harkema, Sybolt; van Hummel, G.J.

    1980-01-01

    3-Nitrobenzo[b]furan and 1-diethylaminopropyne react thermally at 5–10°C to give a 1:1 addition product ( ) in which one of the oxygen atoms of the nitro group is transferred to C-1 of the acetylene. The structure of the benzofuro[3,2-c]isoxazole ( ) has been determined by X-ray crystallography.

  9. Mono and dinuclear arene ruthenium(II) triazoles by 1,3-dipolar cycloadditions to a coordinated azide in ruthenium(II) compounds

    Digital Repository Service at National Institute of Oceanography (India)

    Singh, K.S.; Svitlyk, V.; Mozharivskyj, Y.

    = Me, 3 or Et, 4). In contrast, a similar 1,3-dipolar cycloaddition reaction of (((Eta sup(6)-C sub(6)Me sub(6))Ru(L sub(2))N sub(3))) (2) (where; L sub(2) = tropolone) with acetylene yielded the monomeric triazole compound ((Eta sup(6)-C sub(6)Me sub(6...

  10. Simultaneous description of conductance and thermopower in single-molecule junctions from many-body ab initio calculations

    DEFF Research Database (Denmark)

    Jin, Chengjun; Markussen, Troels; Thygesen, Kristian Sommer

    2014-01-01

    We investigate the electronic conductance and thermopower of a single-molecule junction consisting of bis-(4-aminophenyl) acetylene (B4APA) connected to gold electrodes. We use nonequilibrium Green's function methods in combination with density-functional theory (DFT) and the many-body GW...

  11. The Use of an Air-Natural Gas Flame in Atomic Absorption.

    Science.gov (United States)

    Melucci, Robert C.

    1983-01-01

    Points out that excellent results are obtained using an air-natural gas flame in atomic absorption experiments rather than using an air-acetylene flame. Good results are obtained for alkali metals, copper, cadmium, and zinc but not for the alkaline earths since they form refractory oxides. (Author/JN)

  12. 40 CFR Appendix G to Part 50 - Reference Method for the Determination of Lead in Suspended Particulate Matter Collected From...

    Science.gov (United States)

    2010-07-01

    ... minimize the possibility of generating unreliable data, the user should follow practices established for... chapter—Modifications of methods by users. (Guidance or assistance in requesting approval under Section 2... lead content of the sample is analyzed by atomic absorption spectrometry using an air-acetylene flame...

  13. ATMOSPHERE POLLUTION AT STORAGE OF SLAGS OF ALUMINIUM SECONDARY PROCESSING

    Directory of Open Access Journals (Sweden)

    A. S. Panasyugin

    2013-01-01

    Full Text Available Thermodynamic probability of the processes of the formation of compounds of aluminum (which release in the environment by hydrolysis ammonia, acetylene, propane and hydrogen sulfide is determined. In the article the economic loss from irrecoverable waste of aluminum and fines for emissions of air pollutants is estimated.

  14. selected heavy metals in some vegetables produced through ...

    African Journals Online (AJOL)

    toshiib

    Haramaya University; P. O. Box 138, Dire Dawa, Ethiopia. 10013 ... and trace elements that have potential health benefits [1]. ... leads to a build-up of heavy metals in soils and foods [3]. Exposure of ... Based on the effect of heavy metals on ... (Buck Scientific Model 210VGP AAS, East Norwalk, USA) with air-acetylene flame.

  15. The Synthesis of Nitrogen-Doped Multiwalled Carbon Nanotubes ...

    African Journals Online (AJOL)

    ACVDmethod was used to prepare high-quality nitrogen-doped multiwalled carbon nanotubes (N-MWCNTs) using acetonitrile as the nitrogen and carbon source and acetylene as a carbon source over an Fe-Co/CaCO3 catalyst in the temperature range 700–850 °C. This represents a continuation of earlier work in which ...

  16. Hibiscus sabdariffa L.

    African Journals Online (AJOL)

    Sanoussi

    2013-05-31

    acetylene flame where they were vaporized and the ... The reaction took place in a buffered alkaline medium at pH: 12.8 to. 13.0. ... Values in the same line followed by the same letter (s) are not significantly different (P< 0.05).

  17. ''Titration'' polymerization of monovinylacetylene

    NARCIS (Netherlands)

    Mavinkurve, A; Visser, S; vandenBroek, W; Pennings, AJ

    1996-01-01

    A polymer consisting of a saturated carbon backbone with pendent acetylenic groups was prepared from monovinylacetylene. A titration was performed between the monomer and tertiary butyllithium, its lithiating agent. The charge transfer complex formed between the solvent THF and the tertiary

  18. Photo- and heterotrophic nitrogenase activity by the cyano-bacterium Nostoc in symbiosis with the bryophyte Anthoceros

    International Nuclear Information System (INIS)

    Steinberg, N.A.; Meeks, J.C.

    1987-01-01

    In symbiosis with Anthoceros, Nostoc is thought to do little or no photosynthesis. However, light-dependent 14 CO 2 fixation by symbiotic Nostoc, freshly isolated from pure cultures of the reconstituted Anthoceros-Nostoc association, was 16% of that by free-living Nostoc. A DCMU-resistant mutant of Nostoc was isolated that fixed CO 2 at rates comparable to wild-type in both symbiotic and free-living growth states. To determine if symbiotic Nostoc can use its photosynthate directly to fix nitrogen, acetylene reduction by Anthoceros associations reconstituted with wild-type Nostoc was compared to associations with the DCMU-resistant mutant. In wild-type Anthoceros-Nostoc acetylene reduction was inhibited 97% by 5 μM DCMU, while inhibition of the DCMU-resistant Nostoc association was only 63%. Additions of glucose, fructose, maltose or sucrose to wild-type associations completely restored DCMU-inhibited acetylene reduction in the light. Acetylene reduction in the dark was stimulated by glucose, attaining 84% of the uninhibited light-dependent value. The authors conclude that symbiotic Nostoc maintains a pool of photosynthate which supports nitrogenase activity. The pool can also be supplemented from plant sources

  19. Photonic Crystal Fibres for Dispersion and Sensor Applications

    DEFF Research Database (Denmark)

    Sørensen, Thorkild

    2005-01-01

    of the involved nonlinear processes. A hollow-core photonic crystal fibre (HC-PCF) is used as a sensor for gas. It is filled with two gasses, 12C2H2 acetylene, and H13CN hydrogen cyanide, and the transmission spectra are subject for a discussion. A model for infusion speed of fluids to a capillary presented...

  20. Low-noise mid-IR upconversion detector for improved IR-degenerate four-wave mixing gas sensing

    DEFF Research Database (Denmark)

    Høgstedt, Lasse; Dam, Jeppe Seidelin; Sahlberg, Anna-Lena

    2014-01-01

    -to-noise ratio. The two detectors are compared for the detection of a coherent degenerate four-wave mixing (DFWM) signal in the mid-infrared, and applied to measure trace-level acetylene in a gas flow at atmospheric pressure, probing its fundamental rovibrational transitions. In addition to lower noise...

  1. Pulmonary Effects of Pyrotechnically Disseminated Titanium Dioxide Smoke in Rats

    Science.gov (United States)

    2007-05-01

    Series Perkin Elmer AA (Boston, MA) with a nitrous oxide/acetylene burner head. Hollow cathode lamp elements specific for each metal were used. The primary...supematant was removed from the cell pellet . The pellet was resuspended in 1 mL of 50% bovine serum albumin and total cell counts were taken on a ZBI

  2. Interaction of UV laser pulses with reactive dusty plasmas

    NARCIS (Netherlands)

    van de Wetering, F.M.J.H.; Beckers, J.; Nijdam, S.; Oosterbeek, W.; Kovacevic, E.; Berndt, J.

    2016-01-01

    This contribution deals with the effects of UV photons on the synthesis and transport of nanoparticles in reactive complex plasmas (capacitively coupled RF discharge). First measurements showed that the irradiation of a reactive acetylene-argon plasma with high-energy, ns UV laser pulses (355 nm, 75

  3. N-(pyridylmethyl)azinium salts: precursors of pyridyl-stabilized azinium N-ylides

    OpenAIRE

    Agejas Chicharro, Francisco Javier; Cuadro Palacios, Ana María; Pastor Maeso, Manuel; Vaquero López, Juan José; García Navío, José Luis; Álvarez-Builla Gómez, Julio

    1995-01-01

    A series of new N-(pyridylmethyl)azinium salts have been synthesized from 2, 4, 6-triphenylpyrylium tetrafluoroborate. Generation of azinium N-ylides in the presence of base, has been proved by reactions with electrophiles, such as carbon disulphide, phenyl isothiocyanate and with acetylene dipolarophiles. Ministerio de Educación y Ciencia

  4. Fibrous hydroxyapatite-carbon nanotube composites by chemical vapor deposition : In situ fabrication, structural and morphological characterization

    NARCIS (Netherlands)

    Kosma, Vassiliki; Tsoufis, Theodoros; Koliou, Theodora; Kazantzis, Antonios; Beltsios, Konstantinos; De Hosson, Jeff Th. M.; Gournis, Dimitrios

    2013-01-01

    Fibrous hydroxyapatite (HA)-carbon nanotube composites were synthesized by the catalytic decomposition of acetylene over Fe-Co bimetallic catalysts supported on the fibrous HA. Two forms of fibrous HA (distinct needle-like monocrystals and spherulitic aggregates of needles) were synthesized using a

  5. Journal of Biosciences | Indian Academy of Sciences

    Indian Academy of Sciences (India)

    To estimate the N2 fixation ability of the alder (Alnus hirsuta (Turcz.) var. sibirica), we examined the seasonal variation in nitrogenase activity of nodules using the acetylene reduction method in an 18-year-old stand naturally regenerated after disturbance by road construction in Japan. To evaluate the contribution of N2 ...

  6. Carboxymethyl chitosan/conducting polymer as water-soluble composite binder for LiFePO4 cathode in lithium ion batteries

    Science.gov (United States)

    Zhong, Haoxiang; He, Aiqin; Lu, Jidian; Sun, Minghao; He, Jiarong; Zhang, Lingzhi

    2016-12-01

    A water-soluble conductive composite binder consisting of carboxymethyl chitosan (CCTS) as a binder and poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) as a conduction-promoting agent is reported for the LiFePO4 (LFP) cathode in Li-ion batteries. The introduction of conductive PEDOT:PSS as a conductive composite binder facilitates the formation of homogeneous and continuous conducting bridges throughout the electrode and raises the compaction density of the electrode sheet by decreasing the amounts of the commonly used conducting agent of acetylene black. The optimized replacement ratios of acetylene black with PEDOT:PSS (acetylene black/PEDOT:PSS = 1:1, by weight) are obtained by measuring electrical conductivity, peel strength and compaction density of the electrode sheets. The LFP half-cell with the optimized conductive binder exhibits better cycling and rate performance and more favorable electrochemical kinetics than that using only acetylene black conducting agent. The pilot application of PEDOT:PSS/CCTS binder in 10 Ah CCTS-LFP prismatic cell exhibits a comparable cycling performance, retaining 89.7% of capacity at 1 C/2 C (charge/discharge) rate as compared with 90% for commercial PVDF-LFP over 1000 cycles, and better rate capability than that of commercial PVDF-LFP, retaining 98% capacity of 1 C at 7 C rate as compared with 95.4% for PVDF-LFP.

  7. Author Details

    African Journals Online (AJOL)

    Edwards, R A. Vol 3 (1996) - Articles Properties of paraffin/ethanol mixtures. II. Vapour pressures in paraffin/ethanol systems. Abstract PDF · Vol 3 (1996) - Articles Biological nitrogen fixation by inoculated soya beans in pure and mixed culture with maize as estimated by the Acetylene Reduction Assay. Abstract PDF.

  8. A novel approach for a C-11C bond formation: synthesis of 17α-([11C]prop-1-ynyl)-3-methoxy-3,17β-estradiol

    International Nuclear Information System (INIS)

    Wuest, F.; Zessin, J.

    2002-01-01

    A novel method for a 11 C-C bond formation was developed, employing a cross-coupling reaction between a terminal acetylene and [ 11 C]methyl iodide. The method was used for the synthesis of 17α-([ 11 C]prop-1-ynyl)-3-methoxy-3,17β-estadiol. (orig.)

  9. [Severe ocular burns by calcium carbide in a speleologist: a case report].

    Science.gov (United States)

    Testud, F; Voegtlé, R; Nordmann, J P; Descotes, J

    2002-03-01

    A case of severe ocular burns in an amateur speleologist is reported. The explosion of his acetylene lamp caused the projection of calcium carbide particles, which induced burning of the cornea and conjunctiva in both eyes. He slowly recovered in several months. The pathophysiology of the burns, linked to the in situ production of lime, and their management are discussed.

  10. Post-cold-storage conditioning time affects soil denitrifying enzyme activity

    DEFF Research Database (Denmark)

    Chirinda, Ngonidzashe; Olesen, Jørgen Eivind; Porter, John Roy

    2011-01-01

    Soil denitrifying enzyme activity (DEA) is often assessed after cold storage. Previous studies using the short-term acetylene inhibition method have not considered conditioning time (post-cold-storage warm-up time prior to soil analysis) as a factor influencing results. We observed fluctuations...

  11. Triazole: a unique building block for the construction of functional materials.

    Science.gov (United States)

    Juríček, Michal; Kouwer, Paul H J; Rowan, Alan E

    2011-08-21

    Over the past 50 years, numerous roads towards carbon-based materials have been explored, all of them being paved using mainly one functional group as the brick: acetylene. The acetylene group, or the carbon-carbon triple bond, is one of the oldest and simplest functional groups in chemistry, and although not present in any of the naturally occurring carbon allotropes, it is an essential tool to access their synthetic carbon-rich family. In general, two strategies towards the synthesis of π-conjugated carbon-rich structures can be employed: (a) either the acetylene group serves as a building block to access acetylene-derived structures or (b) it serves as a synthetic tool to provide other, usually benzenoid, structures. The recently discovered copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction, however, represents a new powerful alternative: it transforms the acetylene group into a five-membered heteroaromatic 1H-1,2,3-triazole (triazole) ring and this gives rise to new opportunities. Compared with all-carbon aromatic non-functional rings, the triazole ring possesses three nitrogen atoms and, thus, can serve as a ligand to coordinate metals, or as a hydrogen bond acceptor and donor. This Feature Article summarises examples of using the triazole ring to construct conjugation- and/or function-related heteroaromatic materials, such as tuneable multichromophoric covalent ensembles, macrocyclic receptors or responsive foldamers. These recent examples, which open a new sub-field within organic materials, started to appear only few years ago and represent "a few more bricks" on the road to carbon-rich functional materials. This journal is © The Royal Society of Chemistry 2011

  12. Nitrogen fixation by the Azolla-Anabaena azollae symbiosis

    International Nuclear Information System (INIS)

    Becking, J.H.

    1985-01-01

    A concise outline is presented on the main characteristics of the Azolla association in relation to tropical wetland rice cultivation and the nitrogen economy of paddy soils. Due to the presence of a nitrogen fixing cyanobiont occurring in a special leaf cavity of the Azolla leaf, the water fern Azolla can grow in a nitrogen-deficient environment and is able to contribute considerably to the nitrogen status of the soil. An experimental set-up is presented for how the nitrogen-fixing capacity of Azolla plants can be measured in the field by means of the acetylene reduction assay using a rather simple glass vessel. A comparison was made between 15 N 2 fixation by Azolla and acetylene reduction of Azolla plants under identical conditions

  13. Particulate Filtration from Emissions of a Plasma Pyrolysis Assembly Reactor Using Regenerable Porous Metal Filters

    Science.gov (United States)

    Agui, Juan H.; Abney, Morgan; Greenwood, Zachary; West, Philip; Mitchell, Karen; Vijayakumar, R.; Berger, Gordon M.

    2017-01-01

    Microwave-based plasma pyrolysis technology is being studied as a means of supporting oxygen recovery in future spacecraft life support systems. The process involves the conversion of methane produced from a Sabatier reactor to acetylene and hydrogen, with a small amount of solid carbon particulates generated as a side product. The particles must be filtered before the acetylene is removed and the hydrogen-rich gas stream is recycled back to the CRA. We discuss developmental work on porous metal media filters for removing the carbon particulate emissions from the PPA exit gas stream and to provide in situ media regeneration capability. Because of the high temperatures involved in oxidizing the deposited carbon during regeneration, there was particular focus in this development on the materials that could be used, the housing design, and heating methods. This paper describes the design and operation of the filter and characterizes their performance from integrated testing at the Environmental Chamber (E-Chamber) at MSFC.

  14. Radiation effects on polyacetylenes having substituents

    International Nuclear Information System (INIS)

    Higashimura, Toshinobu; Tang, Ben-Zhong; Masuda, Toshio; Yamaoka, Hitoshi; Matsuyama, Tomochika.

    1985-01-01

    Effects of γ-ray irradiation on high molecular weight polyacetylenes with various substituents were studied in air and in vacuum. The molecular weights of polymers from aliphatic disubstituted acetylenes (2-octyne and 2-decyne) remarkably reduced with irradiation in air. Their G values for chain scission in air were as high as 3 - 12, whereas no degradation occurred in vacuum. The degraded polymers contain carbonyl and hydroxyl groups, and are soluble in polar solvents such as methyl ethyl ketone and acetone. In contrast, polymers of aromatic disubstituted acetylenes (1-phenyl-1-propyne and 1-chloro-2-phenylacetylene) hardly degraded in air even with irradiation up to 40 Mrad. The degradation behavior of poly(t-butylacetylene) was intermediate between those of the above aliphatic and aromatic polymers. Thus the radiolysis of polyacetylenes was found to be greatly dependent on the kind of substituents. (author)

  15. Matrix effects on the determination of manganese in geological materials by atomic-absorption spectrophotometry under different flame conditions

    Science.gov (United States)

    Sanzolone, R.F.; Chao, T.T.

    1978-01-01

    Suppression caused by five of the seven matrix elements studied (Si, Al, Fe, Ca and Mg) was observed in the atomic-absorption determination of manganese in geological materials, when synthetic solutions and the recommended oxidizing air-acetylene flame were used. The magnitude of the suppression effects depends on (1) the kind and concentration of the interfering elements, (2) the type of acid medium, and (3) the concentration of manganese to be determined. All interferences noted are removed or alleviated by using a reducing nitrous oxide-acetylene flame. The atomic-absorption method using this flame can be applied to the determination of total and extractable manganese in a wide range of geological materials without interferences. Analyses of six U.S. Geological Survey rock standards for manganese gave results in agreement with the reported values. ?? 1978.

  16. Nitrous oxide reduction in nodules: denitrification or N2 fixation?

    International Nuclear Information System (INIS)

    Coyne, M.S.; Focht, D.D.

    1987-01-01

    Detached cowpea nodules that contained a nitrous oxide reductase-positive (Nor + ) rhizobium strain (8A55) and a nitrous oxide reductase-negative (Nor - ) rhizobium strain (32H1) were incubated with 1% 15 N 2 O (95 atom% 15 N) in the following three atmospheres: aerobic with C 2 H 2 (10%), aerobic without C 2 H 2 , and anaerobic (argon atmosphere) without C 2 H 2 . The greatest production of 15 N 2 occurred anaerobically with 8A55, yet very little was formed with 32H1. Although acetylene reduction activity was slightly higher with 32H1, about 10 times more 15 N 2 was produced aerobically by 8A55 than by 32H1 in the absence of acetylene. The major reductive pathway of N 2 O reduction by denitrifying rhizobium strain 8A55 is by nitrous oxide reductase rather than nitrogenase

  17. Synthesis of the mevalonic acid labelled with "1"4C, "1"3C and "3H

    International Nuclear Information System (INIS)

    Rousseau, Bernard

    1982-01-01

    This thesis describes five new methods of synthesis of the (R,S) mevalonic acid adapted to the labelling with "1"4C and "1"3C in positions 4,5 or 5 or 3', or with tritium in position 3'. Three of them use the tri-oxa-2,4,10 adamantyl group as masked carboxyl function. The two others take benefit from the regioselectivity of the bis-hydro-boration of terminal acetylenics by the 9-borabicyclo [3-3-1]nonane. The acylation of the bis-trimethylsilyl lithiomalonate, and the chemistry of dithiannes are also involved. Acetylene and methyl iodide labelled with isotopes are used as cheap base products [fr

  18. Acetylene–ammonia–18-crown-6 (1/2/1

    Directory of Open Access Journals (Sweden)

    Tobias Grassl

    2012-10-01

    Full Text Available The title compound, C2H2·C12H24O6·2NH3, was formed by co-crystallization of 18-crown-6 and acetylene in liquid ammonia. The 18-crown-6 molecule has threefold rotoinversion symmetry. The acteylene molecule lies on the threefold axis and the whole molecule is generated by an inversion center. The two ammonia molecules are also located on the threefold axis and are related by inversion symmetry. In the crystal, the ammonia molecules are located below and above the crown ether plane and are connected by intermolecular N—H...O hydrogen bonds. The acetylene molecules are additionally linked by weak C—H...N interactions into chains that propagate in the direction of the crystallographic c axis. The 18-crown-6 molecule [occupancy ratio 0.830 (4:0.170 (4] is disordered and was refined using a split model.

  19. Carburization in fluidized bed of carbon-graphite materials

    Energy Technology Data Exchange (ETDEWEB)

    Murav' ev, V I

    1977-01-01

    A study has been made of the diffusion saturation with carbon of the surface of titanium alloy VT1-1, molybdenum and 08KP steel with respect to the type of carbographitic materials, methods of pseudoliquefaction and heating in the temperature interval 800 to 1100/sup 0/ deg C. Used as the carburizing materials have been charcoal, acetylene black, charcoal carburizer, graphitized particles, pyrobenzene. The maximum carburizing effect is shown to be possessed by charcoal, the minimum effect - by acetylene black. Carburization in the pseudoliquid layer is 5 to 7 times as intensive as in the case of gas cementation and in a solid carburizer. No oxidation of the materials and hydrogenation of titanium has been observed in the temperature interval under study.

  20. Azide-Alkyne Huisgen [3+2] Cycloaddition Using CuO Nanoparticles

    Directory of Open Access Journals (Sweden)

    Hyunjoon Song

    2012-11-01

    Full Text Available Recent developments in the synthesis of CuO nanoparticles (NPs and their application to the [3+2] cycloaddition of azides with terminal alkynes are reviewed. With respect to the importance of click chemistry, CuO hollow NPs, CuO hollow NPs on acetylene black, water-soluble double-hydrophilic block copolymer (DHBC nanoreactors and ZnO–CuO hybrid NPs were synthesized. Non-conventional energy sources such as microwaves and ultrasound were also applied to these click reactions, and good catalytic activity with high regioselectivity was observed. CuO hollow NPs on acetylene black can be recycled nine times without any loss of activity, and water-soluble DHBC nanoreactors have been developed for an environmentally friendly process.

  1. On the kinetics of high-temperature interaction of tungsten with light hydrocarbons

    International Nuclear Information System (INIS)

    Kharatyan, S.L.; Chatilyan, A.A.; Merzhanov, A.G.

    1989-01-01

    Comparative investigation of tungsten carbidizing treatment in ethylene, acetylene and methane media at T=1750-2500 deg C and p=2-10 Torr is carried out by the electrothermographical method. In all cases interaction is shown to proceed in stages due to step-by-step formation of carbide phases of tungsten W 2 C and WC as well as pyrocarbon. It is established that efficiency of carbidizing treatment is turned out to be maximum in methane medium in spite of great absolute values of ethylene and acetylene pyrolysis velocities on the surface of tungsten carbides in comparison with methane. Criterion of carburizing capability of hydrocarbous relatively to a metal is given on the basis of the results obtained

  2. Methane Post-Processor Development to Increase Oxygen Recovery beyond State-of-the-Art Carbon Dioxide Reduction Technology

    Science.gov (United States)

    Abney, Morgan B.; Greenwood, Zachary; Miller, Lee A.; Alvarez, Giraldo; Iannantuono, Michelle; Jones, Kenny

    2013-01-01

    State-of-the-art life support carbon dioxide (CO2) reduction technology, based on the Sabatier reaction, is theoretically capable of 50% recovery of oxygen from metabolic CO2. This recovery is constrained by the limited availability of reactant hydrogen. Post-processing of the methane byproduct from the Sabatier reactor results in hydrogen recycle and a subsequent increase in oxygen recovery. For this purpose, a Methane Post-Processor Assembly containing three sub-systems has been developed and tested. The assembly includes a Methane Purification Assembly (MePA) to remove residual CO2 and water vapor from the Sabatier product stream, a Plasma Pyrolysis Assembly (PPA) to partially pyrolyze methane into hydrogen and acetylene, and an Acetylene Separation Assembly (ASepA) to purify the hydrogen product for recycle. The results of partially integrated testing of the sub-systems are reported

  3. Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

    Directory of Open Access Journals (Sweden)

    Huixin Jiang

    2015-06-01

    Full Text Available A selection of cyclic and acyclic acetylenic scaffolds bearing two tetrathiafulvalene (TTF units was prepared by different metal-catalyzed coupling reactions. The bridge separating the two TTF units was systematically changed from linearly conjugated ethyne, butadiyne and tetraethynylethene (trans-substituted units to a cross-conjugated tetraethynylethene unit, placed in either acyclic or cyclic arrangements. The cyclic structures correspond to so-called radiaannulenes having both endo- and exocyclic double bonds. Interactions between two redox-active TTF units in these molecules were investigated by cyclic voltammetry, UV–vis–NIR and EPR absorption spectroscopical methods of the electrochemically generated oxidized species. The electron-accepting properties of the acetylenic cores were also investigated electrochemically.

  4. Wet chemical synthesis of soluble gold nanogaps

    DEFF Research Database (Denmark)

    Jain, Titoo; Tang, Qingxin; Bjørnholm, Thomas

    2014-01-01

    NRs) in aqueous solution. Through controlled end-to-end assembly of the AuNRs into dimers or chains, facilitated via target molecules, they can be used as electrical contacts. In this way, the preparation of AuNR-molecule-AuNR junctions by wet chemical methods may afford a large number of identical devices...... with little variation in the interface between molecule and electrode (AuNR). In this Account, we highlight recent progress in using chemically synthesized AuNRs as building blocks for molecular electronic applications. We outline the general synthesis and properties of AuNRs and describe the aqueous growth...... in the nanogaps lets us spectroscopically characterize the molecules via surface-enhanced Raman scattering. We discuss the incorporation of oligopeptides functionalized with acetylene units having uniquely identifiable vibrational modes. This acetylene moiety allows chemical reactions to be performed in the gaps...

  5. Integrated process using non-stoichiometric sulfides or oxides of potassium for making less active metals and hydrocarbons

    International Nuclear Information System (INIS)

    Swanson, R.

    1984-01-01

    Disclosed is a combinative integrated chemical process using inorganic reactants and yielding, if desired, organic products. The process involves first the production of elemental potassium by the thermal or thermal-reduced pressure decomposition of potassium oxide or potassium sulfide and distillation of the potassium. This elemental potassium is then used to reduce ores or ore concentrates of copper, zinc, lead, magnesium, cadmium, iron, arsenic, antimony or silver to yield one or more of these less active metals in elemental form. Process potassium can also be used to produce hydrogen by reaction with water or potassium hydroxide. This hydrogen is reacted with potassium to produce potassium hydride. Heating the latter with carbon produces potassium acetylide which forms acetylene when treated with water. Acetylene is hydrogenated to ethene or ethane with process hydrogen. Using Wurtz-Fittig reaction conditions, the ethane can be upgraded to a mixture of hydrocarbons boiling in the fuel range

  6. Determination of 17 impurity elements in nuclear quality uranium compounds by atomic absorption spectroscopy

    International Nuclear Information System (INIS)

    Andonie, O.; Smith, L.A.; Cornejo, S.

    1985-01-01

    A method is described for the determination of 17 elements (Al, Ca, Cd, Co, Cr, Cu, Fe, K, Li, Mg, Mn, Mo, Na, Ni, Pb, V and Zn) in the ppm level, in nuclearly pure uranium compounds by flame atomic absorption spectroscopy. The analysis is performed by first dissolving the uranium sample in nitric acid and then extracting the uranium with tributyl phosphate solution. The aqueous phase, free of uranium, which contains the elements to analyze is inspirated into the flame of an atomic absorption spectrophotometer using air-acetylene or nitrous oxide-acetylene flame according to the element in study. This method allows to extract the uranium selectively in more than 99.0% and the recovery of the elements sudied was larger 90% (for K) to 100% (for Cr). The sensitivity of the method vary from 0.096 μg/g U (for Cd) to 5.5 μg/g U (for Na). (Author)

  7. Measurement of denitrification on grassland using gas chromatography and 15N tracer technique

    International Nuclear Information System (INIS)

    Lippold, H.; Foerster, I.; Hagemann, O.; Matzel, W.

    1981-01-01

    Alternative covering of grassland micro-plots fertilized with 15 NH 4 15 NO 3 allowed on the basis on N 2 and N 2 O quantities released within several weeks to measure denitrification and to calculate it by means of methane as gas tracer. Thus the gas exchange was rendered visible and the N quantities measured could be corrected. In some variants, the acetylene blocking technique was successfully applied by adding acetylene to the soil air. The losses measured at 6 dates are discussed together with the 15 N balance and atmospherical conditions. The method is suited for recording the high losses occurring mainly in the second quarter of the year immediately after fertilization. Under the conditions mentioned soil N losses were small (3 kg N/ha). The immobilized fertilizer N quantities reached 20 to 30 kg/ha (fertilizer rate 100 kg N/ha) and were comparably independent of the date of fertilization. (author)

  8. Controllable synthesis of helical, straight, hollow and nitrogen-doped carbon nanofibers and their magnetic properties

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xun [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Soil and Sustainable Agriculture, Institute of Soil Science, Chinese Academy of Sciences, Nanjing 210008 (China); Xu, Zheng, E-mail: zhengxu@nju.edu.cn [State Key Laboratory of Coordination Chemistry, Nanjing National Laboratory of Microstructure, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093 (China)

    2012-12-15

    Graphical abstract: The helical, straight and hollow carbon nanofibers can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. Display Omitted Highlights: ► CNFs were synthesized via pyrolysis of acetylene on copper NPs. ► The helical, straight, hollow and N-doped CNFs can be selectively synthesized. ► The growth mechanism of different types of CNFs was proposed. -- Abstract: Carbon nanofibers (CNFs) with various morphologies were synthesized by catalytic pyrolysis of acetylene on copper nanoparticles which were generated from the in situ decomposition of copper acetylacetonate. The morphology of the pristine and acid-washed CNFs was investigated by field emission scanning electron microscope and high-resolution transmission electron microscope. Helical, straight and hollow CNFs can be selectively synthesized by adjusting either the reaction temperature or feed gas composition. The growth mechanism for these three types of CNFs was proposed.

  9. Fiber optic gas detection system for health monitoring of oil-filled transformer

    Science.gov (United States)

    Ho, H. L.; Ju, J.; Jin, W.

    2009-10-01

    This paper reports the development of a fiber-optic gas detection system capable of detecting three types of dissolved fault gases in oil-filled power transformers or equipment. The system is based on absorption spectroscopy and the target gases include acetylene (C2H2), methane (CH4) and ethylene (C2H4). Low-cost multi-pass sensor heads using fiber coupled micro-optic cells are employed for which the interaction length is up to 4m. Also, reference gas cells made of photonic bandgap (PBG) fiber are implemented. The minimum detectable gas concentrations for methane, acetylene and ethylene are 5ppm, 2ppm and 50ppm respectively.

  10. Agglomeration processes sustained by dust density waves in Ar/C2H2 plasma: From C2H2 injection to the formation of an organized structure

    International Nuclear Information System (INIS)

    Dap, Simon; Hugon, Robert; Poucques, Ludovic de; Briancon, Jean-Luc; Bougdira, Jamal; Lacroix, David

    2013-01-01

    In this paper, an experimental investigation of dust particle agglomeration in a capacitively coupled RF discharge is reported. Carbonaceous particles are produced in an argon plasma using acetylene. As soon as the particle density becomes sufficient, dust density waves (DDWs) are spontaneously excited within the cathode sheath. Recently, it was proven that DDWs can significantly enhance the agglomeration rate between particles by transferring them a significant kinetic energy. Thus, it helps them to overcome Coulomb repulsion. The influence of this mechanism is studied from acetylene injection to the formation of very large agglomerates forming an organized structure after a few dozens of seconds. For this purpose, three diagnostic tools are used: extinction measurements to probe nanometer-sized particles, fast imaging for large agglomerates and a dust extraction technique developed for ex-situ analysis.

  11. Analysis of uranium concentrates by atomic-absorption spectrometry

    International Nuclear Information System (INIS)

    Naeem, M.; Capdevila, C.; Alduan, F.A.

    1977-01-01

    The determination of As, Ca, Fe, Mo and V in uranium concentrates, removing the bulk of the uranium matrix by extracting with tributyl phosphate in hexane has been tried. No interferences were found due to uranium, sodium, aluminium, sulfates and phosphates. Only for calcium a depressive effect of aluminium and uranium has been found and it is overcome by addition of lanthanum. Air-acetylene flame for Fe, Ca and As, and nitrous oxide-acetylene flame for Mo and V have been used. The considered concentration range has been 0.15 - 3% for Ca and Fe, 0.1 -2% for As and 0.1 - 1% for Mo and V. (author) [es

  12. Combustion-assisted laser cutting of a difficult-to-machine superalloy

    International Nuclear Information System (INIS)

    Molian, P.A.

    1992-01-01

    In laser cutting, the largest single application of lasers in manufacturing, the assist gas plays an important role in affecting the cutting performance. The assist gas is usually oxygen or an inert gas. In this paper acetylene and oxygen was employed to create combustion reactions during CO 2 laser cutting that enabled an improvement in the cutting speed, and cut quality of a difficult-to-machine superalloy. A comparison with laser cutting of a plain carbon steel under identical conditions was also made to determine the usefulness of combustion energy. Results indicate that both cutting speed and quality are enhanced by the reduction in the viscosity of slag formed during cutting (which assisted in ejection of the slag through the bottom of the kerf) due to the heat released by the acetylene burning inside the kerf. Correlations of experimental data with a theoretical model provided the influence of combustion power and gas-flow power on the cutting phenomena

  13. Determination of yttrium using YO band head obtained by laser enhanced ionization spectrometry

    International Nuclear Information System (INIS)

    Deshpande, S.S.; Khanna, P.P.

    1997-04-01

    The determination of yttrium (Y) in water in the concentration range of 2 μg/ml to 200 μg/ml by laser enhanced ionisation (LEI) technique is reported. The YO band head at 584.27 nm belonging to A 2 Π - X 2 Σ + system is used for LEI signal detection. It is also shown that the LEI signal is enhanced when the mixture of air - acetylene - argon (AAA) is used instead of commonly used air-acetylene (AA) mixture. In the present work an XeCl laser (308 nm) pumped rhodamine 6G dye laser, covering a range of 570-610 nm is used. The sample/standard in solution form is aspirated into the flame with pneumatic nebulizer. The working curve is a straight line showing linear dependence of LEI signal with yttrium concentration. The relative standard deviation calculated at 100 μg/ml is found to be 2.4 %. (author)

  14. Synthesis of [14C]-labelled eicosa-5,8,11-triynoic acid and conversion to anti-inflammatory amides

    International Nuclear Information System (INIS)

    Pilgrim, W.R.; Nedoncelle, P.; Shroot, B.; Maignan, J.; Restle, S.

    1991-01-01

    A four step synthesis of [5,6- 14 C]-eicosa-5,8,11-triynoic acid from [ 14 C]-labelled acetylene is described. [ 14 C 2 ]-acetylene was converted to 5-chloro-[1,2- 14 C]-pentyne via reaction of its monolithium salt with 3-bromo-1-chloropropane. The doubly labelled 5-chloropentyne thus obtained was transformed to [5,6- 14 C]-hex-5-ynoic acid which was then coupled with 1-chloro-tetradeca-2,5-diyne to give the title compound. Using 2-(2-aminoethoxy)ethanol and 1-(2-hydroxyethyl)piperazine, amides which had previously been found to be potent inhibitors of the 5-lipoxygenase enzyme, were prepared from [ 14 C-labelled eicosatriynoic acid by way of acylimidazole chemistry. (author)

  15. Synthesis of ( sup 14 C)-labelled eicosa-5,8,11-triynoic acid and conversion to anti-inflammatory amides

    Energy Technology Data Exchange (ETDEWEB)

    Pilgrim, W R; Nedoncelle, P; Shroot, B [Centre International de Recherches Dermatologiques Galderma, Valbonne (France); Maignan, J; Restle, S [L' Oreal, Lab. de Recherches Fondamentales, Aulnay sous Bois, (France)

    1991-07-01

    A four step synthesis of (5,6-{sup 14}C)-eicosa-5,8,11-triynoic acid from ({sup 14}C)-labelled acetylene is described. ({sup 14}C{sub 2})-acetylene was converted to 5-chloro-(1,2-{sup 14}C)-pentyne via reaction of its monolithium salt with 3-bromo-1-chloropropane. The doubly labelled 5-chloropentyne thus obtained was transformed to (5,6-{sup 14}C)-hex-5-ynoic acid which was then coupled with 1-chloro-tetradeca-2,5-diyne to give the title compound. Using 2-(2-aminoethoxy)ethanol and 1-(2-hydroxyethyl)piperazine, amides which had previously been found to be potent inhibitors of the 5-lipoxygenase enzyme, were prepared from ({sup 14}C)-labelled eicosatriynoic acid by way of acylimidazole chemistry. (author).

  16. Nitrogen fixation, denitrification, and ecosystem nitrogen pools in relation to vegetation development in the Subarctic

    DEFF Research Database (Denmark)

    Sørensen, Pernille Lærkedal; Jonasson, Sven Evert; Michelsen, Anders

    2006-01-01

    Nitrogen (N) fixation, denitrification, and ecosystem pools of nitrogen were measured in three subarctic ecosystem types differing in soil frost-heaving activity and vegetation cover. N2-fixation was measured by the acetylene reduction assay and converted to absolute N ecosystem input by estimates...... of conversion factors between acetylene reduction and 15N incorporation. One aim was to relate nitrogen fluxes and nitrogen pools to the mosaic of ecosystem types of different stability common in areas of soil frost movements. A second aim was to identify abiotic controls on N2-fixation by simultaneous...... measurements of temperature, light, and soil moisture. Nitrogen fixation rate was high with seasonal input estimated at 1.1 g N m2 on frostheaved sorted circles, which was higher than the total plant N content and exceeded estimated annual plant N uptake several-fold but was lower than the microbial N content...

  17. Direct regeneration of recycled cathode material mixture from scrapped LiFePO4 batteries

    Science.gov (United States)

    Li, Xuelei; Zhang, Jin; Song, Dawei; Song, Jishun; Zhang, Lianqi

    2017-03-01

    A new green recycling process (named as direct regeneration process) of cathode material mixture from scrapped LiFePO4 batteries is designed for the first time. Through this direct regeneration process, high purity cathode material mixture (LiFePO4 + acetylene black), anode material mixture (graphite + acetylene black) and other by-products (shell, Al foil, Cu foil and electrolyte solvent, etc.) are recycled from scrapped LiFePO4 batteries with high yield. Subsequently, recycled cathode material mixture without acid leaching is further directly regenerated with Li2CO3. Direct regeneration procedure of recycled cathode material mixture from 600 to 800 °C is investigated in detail. Cathode material mixture regenerated at 650 °C display excellent physical, chemical and electrochemical performances, which meet the reuse requirement for middle-end Li-ion batteries. The results indicate the green direct regeneration process with low-cost and high added-value is feasible.

  18. Cyclopropanes and hypervalent iodine reagents: high energy compounds for applications in synthesis and catalysis.

    Science.gov (United States)

    Fernández González, Davinia; De Simone, Filippo; Brand, Jonathan P; Nicolai, Stefano; Waser, Jérôme

    2011-01-01

    One of the major challenges faced by organic chemistry is the efficient synthesis of increasingly complex molecules. Since October 2007, the Laboratory of Catalysis and Organic Synthesis (LCSO) at EPFL has been working on the development of catalytic reactions based on the Umpolung of the innate reactivity of functional groups. Electrophilic acetylene synthons have been developed using the exceptional properties of ethynyl benziodoxolone (EBX) hypervalent iodine reagents for the alkynylation of heterocycles and olefins. The obtained acetylenes are important building blocks for organic chemistry, material sciences and chemical biology. The ring-strain energy of donor-acceptor cyclopropanes was then used in the first catalytic formal homo-Nazarov cyclization. In the case of aminocyclopropanes, the method could be applied in the synthesis of the alkaloids aspidospermidine and goniomitine. The developed methods are expected to have a broad potential for the synthesis and functionalization of complex organic molecules, including carbocycles and heterocycles.

  19. Pengaruh Sambungan Las pada Material Aluminium-Magnesium pada Body Pesawat Tanpa Awak Terhadap Beban Impak dan Cacat Las

    OpenAIRE

    Tanjung, Dahlan

    2015-01-01

    Welding is an integral part of the growth due to an increase in industry- a major role in engineering and repair of metal production . Making it nearly impossible without involving the construction of a factory welding element . Not all metals have good weldability properties . In order to obtain a good quality connection with Oxy Acetylene welding using Welding ( ÖAW ) on - Magnesium Aluminum alloy material is required for the welding certificate . Limitations of this study is the issue on t...

  20. Enhanced catalytic activity through the tuning of micropore environment and supercritical CO2 processing: Al(porphyrin)-based porous organic polymers for the degradation of a nerve agent simulant.

    Science.gov (United States)

    Totten, Ryan K; Kim, Ye-Seong; Weston, Mitchell H; Farha, Omar K; Hupp, Joseph T; Nguyen, SonBinh T

    2013-08-14

    An Al(porphyrin) functionalized with a large axial ligand was incorporated into a porous organic polymer (POP) using a cobalt-catalyzed acetylene trimerization strategy. Removal of the axial ligand afforded a microporous POP that is catalytically active in the methanolysis of a nerve agent simulant. Supercritical CO2 processing of the POP dramatically increased the pore size and volume, allowing for significantly higher catalytic activities.

  1. Potential Use Of Carbide Lime Waste As An Alternative Material To Conventional Hydrated Lime Of Cement-Lime Mortars

    OpenAIRE

    Al Khaja, Waheeb A.

    1992-01-01

    The present study aimed at the possibility of using the carbide lime waste as an alternative material to the conventional lime used for cement-lime mortar. The waste is a by-product obtained in the generation of acetylene from calcium carbide. Physical and chemical properties of the wastes were studied. Two cement-lime-sand mix proportions containing carbide lime waste were compared with the same mix proportions containing conventional lime along with a control mix without lime. Specimens wer...

  2. Purification and measurement of acid leachable europium in sands as an aid in the study of sediment transport

    International Nuclear Information System (INIS)

    Ditchburn, R.G.; McCabe, W.J.

    1982-05-01

    The use of europium labelled sand as an aid in the study of sediment transport has been suggested. A method for the purification of acid leachable europium is described. The final measurement is made by flame emission spectrometry using a nitrous oxide-acetylene flame. The usefulness of the method is limited by the natural levels of europium which, in the sand studied, was around 0.3 ppm

  3. Cost regulation on the inspection of plants requiring supervision

    International Nuclear Information System (INIS)

    Anon.

    1981-01-01

    According to annexes I to VI of this regulation, TUeVs (technical control authorities) (2nd sentence of para. 1 of sect. 24 c of the trade law) collect fees for inspections ordered by the authorities for the following plants and installations: 1. steam boiler plants, 2. pressure vessels, high-pressure gas vessels, feeders, 3. lifts, 4. acetylene plants, 5. plants for the storage, racking and transport of combustile liquids, 6. electrical installations on hazardous location. (orig.) [de

  4. Influence of conductive electroactive polymer polyaniline on ...

    Indian Academy of Sciences (India)

    Conductive electroactive polymer polyaniline is utilized to substitute conductive additive acetylene black in the LiMn1.95Al0.05O4 cathode for lithium ion batteries. Results show that LiMn1.95Al0.05O4 possesses stable structure and good performance. Percolation theory is used to optimize the content of conductive additive ...

  5. Field electron emission from branched nanotubes film

    International Nuclear Information System (INIS)

    Zeng Baoqing; Tian Shikai; Yang Zhonghai

    2005-01-01

    We describe the preparation and analyses of films composed of branched carbon nanotubes (CNTs). The CNTs were grown on a Ni catalyst film using chemical vapor deposition from a gas containing acetylene. From scanning electron microscope (SEM) and transmission electron microscope (TEM) analyses, the branched structure of the CNTs was determined; the field emission characteristics in a vacuum chamber indicated a lower turn on field for branched CNTs than normal CNTs

  6. Topological analysis of valence electron charge distributions from semiempirical and ab initio methods

    International Nuclear Information System (INIS)

    Ho, Minhhuy; Schmider, H.; Edgecombe, K.E.

    1994-01-01

    Topological properties of the charge density p(→) of a series of diatomic molecules, as well as ethane, ethene, and acetylene are calculated at the Hartree-Fock level employing various basis sets, and by the AM1 method. The effect of the core orbitals on the bonding regions in these molecules is examined. The results help to evaluate the utility of AM1 wavefunctions for analyzing the topological properties of the charge density

  7. Growth of vertically aligned multiwalled carbon nanotubes forests on metal alloy Ni-Nb-N with low content of catalyst

    Science.gov (United States)

    Dubkov, S.; Trifonov, A.; Shaman, Yu; Pavlov, A.; Shulyat'ev, A.; Skorik, S.; Kirilenko, E. P.; Rygalin, B.

    2016-08-01

    This research shows the possibility of carbon nanotubes (CNTs) formation on the surface of low nickel (∼ 10 at.%) Ni-Nb-N amorphous metal alloy film by CVD method at 550 °C of the gas mixture based on acetylene. The structure of CNT were studied by transmission and scanning-electron microscopy, energy-dispersive X-ray and the Raman spectroscopy.

  8. Synthesis of Fluorinated Amphiphilic Block Copolymers Based on PEGMA, HEMA, and MMA via ATRP and CuAAC Click Chemistry

    OpenAIRE

    Erol, Fatime Eren; Sinirlioglu, Deniz; Cosgun, Sedat; Muftuoglu, Ali Ekrem

    2014-01-01

    Synthesis of fluorinated amphiphilic block copolymers via atom transfer radical polymerization (ATRP) and Cu(I) catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) was demonstrated. First, a PEGMA and MMA based block copolymer carrying multiple side-chain acetylene moieties on the hydrophobic segment for postfunctionalization was carried out. This involves the synthesis of a series of P(HEMA-co-MMA) random copolymers to be employed as macroinitiators in the controlled synthesis of P(HEMA-co-M...

  9. N2-fixation by freshly isolated Nostoc from coralloid roots of the cycad Macrozamia riedlei (Fisch. ex Gaud.) Gardn

    International Nuclear Information System (INIS)

    Lindblad, P.; Atkins, C.A.; Pate, J.S.

    1991-01-01

    Nitrogenase (EC 1.7.99.2) activity (acetylene reduction) and nitrogen fixation ( 15 N 2 fixation) were measured in cyanobacteria freshly isolated from the coralloid roots of Macrozamia riedlei (Fisch. ex Gaud.) Gardn. The data indicate that cyanobacteria within cycad coralloid roots are differentiated specifically for symbiotic functioning in a microaerobic environment. Specializations include a high heterocyst frequency, enhanced permeability to O 2 , and a direct dependence on the cycad for substrates to support nitrogenase activity

  10. Flame emission spectrometry using atomic absorption apparatus. I. Determination of Sr in sea water

    International Nuclear Information System (INIS)

    Aizawa, S.; Yoshimura, E.; Hamachi, M.; Haraguchi, H.; Dokiya, Y.; Fuwa, K.

    1976-01-01

    Flame emission determination of Sr in seawater was studied using an ordinary atomic absorption apparatus. The analytical line 4607 A was used with a background correction at 4616 A. The ionization was negligible in an air acetylene flame with seawater, and the interference of H 2 SO 4 was eliminated using the higher part of the flame. Sr concentration of seawater of Tokyo Bay and Sagami Bay has been determined

  11. Hazardous Materials Hazard Analysis, Portland, Oregon.

    Science.gov (United States)

    1981-06-01

    poisons and flammables are found in all agriculture and garden supply shops, automotive repair facilities, retail paint and hardware stores, etc...Peroxide rompressed Gases and Welding 4 NON-FLAMMABLE GAS: Surpplies Liquid Nitrogen FLAMMABLE GAS: Acetylene Hydrogen Propane Propylene Oxide OTHER...this small community said Sunday and where the water and the chemicals and 16,000 bags of chemicals were de- that he was upset with the way officials

  12. Processes in petroleum chemistry. Technical and economical characteristics Vol. 1. Synthesis gas and derivatives. Main hydrocarbon intermediaries (2 ed. )

    Energy Technology Data Exchange (ETDEWEB)

    Chauvel, A.; Lefebvre, G.; Castex, L.

    1985-01-01

    The aim of this book is to give rudiments for a preliminary study to outline petrochemical operation and cost estimation. Basic operations are examined: Steam reforming or partial oxidation, steam or thermal cracking and catalytic reforming. The main topics examined include: hydrogen purification, hydrogen fabrication from hydrocarbons, carbonaceous materials or water, production of carbon monoxide, ammoniac synthesis methanol synthesis from synthesis gas, preparation of formol, urea, acetylene and monomers for the preparation of plastics.

  13. Coalescence of 3-phenyl-propynenitrile on Cu(111) into interlocking pinwheel chains

    Science.gov (United States)

    Luo, Miaomiao; Lu, Wenhao; Kim, Daeho; Chu, Eric; Wyrick, Jon; Holzke, Connor; Salib, Daniel; Cohen, Kamelia D.; Cheng, Zhihai; Sun, Dezheng; Zhu, Yeming; Einstein, T. L.; Bartels, Ludwig

    2011-10-01

    3-phenyl-propynenitrile (PPN) adsorbs on Cu(111) in a hexagonal network of molecular trimers formed through intermolecular interaction of the cyano group of one molecule with the aromatic ring of its neighbor. Heptamers of trimers coalesce into interlocking pinwheel-shaped structures that, by percolating across islands of the original trimer coverage, create the appearance of gear chains. Density functional theory aids in identifying substrate stress associated with the chemisorption of PPN's acetylene group as the cause of this transition.

  14. Propargyl organometallic compounds. II. Alkylation of sodium derivatives of 1-alkyl-1-aryl-2-alkynes in liquid ammonia

    International Nuclear Information System (INIS)

    Libman, N.M.; Sevryukov, Yu.P.

    1987-01-01

    In most cases the alkylation of the sodium derivatives of 1-phenyl-1-alkyl-2-alkynes by methyl, ethyl, isopropyl, and tert-butyl bromides in liquid ammonia takes place preferentially at the sp 2 -hybridized carbon atom, and this leads to the formation of the corresponding acetylenes, The regioselectivity of the reaction is explained by the greater softness of the trigonal atom of the ambient propargyl anion and its smaller screening by the solvate shell compared with the diagonal atom

  15. Process and Energy Optimization Assessment, Tobyhanna Army Depot, PA

    Science.gov (United States)

    2006-04-17

    assembly of electronic-communication components, different welding processes are performed at TYAD. It uses shielded arc, metal inert gas (MIG...tungsten inert gas ( TIG ), and silver braz- ing oxygen/acetylene cutting plasma arc methods to complete mission re- quirements. Major welding jobs are...ER D C/ CE R L TR -0 6 -1 1 Process and Energy Optimization Assessment Tobyhanna Army Depot, PA Mike C.J. Lin, Alexander M. Zhivov

  16. Interaction between Two-Dimensional Sonic Jets and Supersonic Flow to Model Heat Addition in a Supersonic Combustor.

    Science.gov (United States)

    1987-12-01

    pressure between two Mach 3 flows approachs absolute zero , Pb=.04 psia for Pop= 100 psia. However, viscous effects increase the base pressure. Korst theory...this problem. Acetylene was chosen as the primary fuel because of its relatively low spontaneous ignition temperature, 581 degrees Farenheit , and high...with the corresponding test section. The exit dimension could be adjusted with a screw mechanism from zero to 2.625 inches. A bracket to hold a .250

  17. Electrostatics determine vibrational frequency shifts in hydrogen bonded complexes.

    Science.gov (United States)

    Dey, Arghya; Mondal, Sohidul Islam; Sen, Saumik; Ghosh, Debashree; Patwari, G Naresh

    2014-12-14

    The red-shifts in the acetylenic C-H stretching vibration of C-H∙∙∙X (X = O, N) hydrogen-bonded complexes increase with an increase in the basicity of the Lewis base. Analysis of various components of stabilization energy suggests that the observed red-shifts are correlated with the electrostatic component of the stabilization energy, while the dispersion modulates the stabilization energy.

  18. Nitrocarburizing in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2011-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammonia-propene-hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  19. Nitrocarburising in ammonia-hydrocarbon gas mixtures

    DEFF Research Database (Denmark)

    Pedersen, Hanne; Christiansen, Thomas; Somers, Marcel A. J.

    2010-01-01

    The present work investigates the possibility of nitrocarburising in ammonia-acetylene-hydrogen and ammoniapropene- hydrogen gas mixtures, where unsaturated hydrocarbon gas is the carbon source during nitrocarburising. Consequently, nitrocarburising is carried out in a reducing atmosphere...... microscopy and X-ray diffraction analysis. It is shown that the use of unsaturated hydrocarbon gas in nitrocarburising processes is a viable alternative to traditional nitrocarburising methods....

  20. 49 CFR 173.301 - General requirements for shipment of compressed gases and other hazardous materials in cylinders...

    Science.gov (United States)

    2010-10-01

    ... less; (vi) A fire extinguisher; or (vii) A “B” style cylinder with a capacity of 40 ft 3 (1.13 m3) or an “MC” style cylinder with a capacity of 10 ft 3 (0.28m3) containing acetylene. (2) For cylinders... citations affecting § 173.301, see the List of CFR Sections Affected, which appears in the Finding Aids...

  1. NMR spectroscopy of selenium and tellurium organic compounds

    International Nuclear Information System (INIS)

    Kalabin, G.A.; Projdakov, A.G.; Radchenko, S.I.

    1980-01-01

    13 C NMR spectra of the substituted methylthio (seleno, telluro) acetylenes, CH 3 EC 1 identity sign C 2 R, E=S, Se, Te are measured. High sensitivity of the chemical shifts of ternary bond carbons to specific effects of heteroatoms is established. The substituent nature produces considerable effect on the sensitivity of C 1 -carbon atom to these effects. Chemical shifts of the substituent carbons do not depend on heteroatoms nature

  2. Combustion Problems in Turbine Engines Held at the Propulsion and Energetics Panel Symposium (62nd) Cesme (Turkey) on 3-6 October 1983

    Science.gov (United States)

    1984-01-01

    Versuche an ruBenden Acetylen-Sauerstoff-Flammen bei niedrigem Druck , Ber.Bunsenges.Phys.Chem. 69, 20 (1965) 12. K.H. Homann, W. Morgeneyer and H.Gg. Wagner... 3D 2 0 02 050 7. 10-S .0 020 . lO S 050 07S 0 Relative Channel Width Y/ HO rig. 14: Calculated static pressure Fig. 13: Calculated isobar% at pliano I

  3. Thallium (III) salts utilization in organic synthesis. Part II

    International Nuclear Information System (INIS)

    Ferraz, H.M.C.

    1989-01-01

    The utilizations of thallium (III) salts in organic synthesis with carbonylic and acitylenic substrates are presented. The reactions of carbonylic substra3ts with kitones and the oxidation reactions of acetylenic substrates are shown. Others reactions including thallium (III) salts and non aromatic unsatured substracts, as cleasage of ethers and epoxide using thallium trinitrate, hydrazones treatments with thallium triacetates, etc, are also mentioned. (C.G.C.) [pt

  4. Effect of structure and deposition technology on tribological properties of DLC coatings alloyed with VIA group metals

    Science.gov (United States)

    Khrushchov, M.; Levin, I.; Marchenko, E.; Avdyukhina, V.; Petrzhik, M.

    2016-07-01

    The results of a comprehensive research on atomic structure, phase composition, micromechanical and tribological characteristics of alloyed DLC coatings have been presented. The coatings have been deposited by reactive magnetron sputtering in acetylene-nitrogen gas mixtures of different compositions (a-C:H:Cr), by plasma-assisted chemical vapor deposition in atmospheres of silicone-organic precursor gases (a-C:H:Mo:Si), and by nonreactive magnetron sputtering of a composite target (a-C:H:W).

  5. Total synthesis of Ivorenolide A following a base-induced elimination protocol.

    Science.gov (United States)

    Mohapatra, Debendra K; Umamaheshwar, Gonela; Rao, R Nageshwar; Rao, T Srinivasa; R, Sudheer Kumar; Yadav, Jhillu S

    2015-02-20

    A concise and stereocontrolled first total synthesis of Ivorenolide A (1) is reported in 16 longest linear steps with a 13.4% overall yield starting from (+)-diethyl tartrate (DET). Key features are base-induced elimination protocol for the construction of chiral propargyl alcohols in both fragments, Pd-catalyzed cross-coupling of terminal acetylenes, and Shiina's 2-methyl-6-nitrobezoic anhydride (MNBA) mediated macrolactonization.

  6. Plastic deformation of particles of zirconium and titanium carbide subjected to vibration grinding

    Energy Technology Data Exchange (ETDEWEB)

    Kravchik, A.E.; Neshpor, V.S.; Savel' ev, G.A.; Ordan' yan, S.S.

    1976-12-01

    A study is made of the influence of stoichiometry on the characteristics of microplastic deformation in powders of zirconium and titanium carbide subjected to vibration grinding. The carbide powders were produced by direct synthesis from the pure materials: metallic titanium and zirconium and acetylene black. As to the nature of their elastic deformation, zirconium and titanium carbides can be considered elastic-isotropic materials. During vibration grinding, the primary fracture planes are the (110) planes. Carbides of nonstoichiometric composition are more brittle.

  7. Synthesis of diamond-like carbon via PECD using a streaming neutral gas injection hollow cathode

    International Nuclear Information System (INIS)

    Pacho, A.; Pares, E.; Ramos, H.; Mendenilla, A.; Malapit, G.

    2009-01-01

    A streaming neutral gas injection hollow cathode system was used to deposit diamond-like carbon films via plasma enhanced chemical vapor deposition on silicon and nickel-coated silicon substrates with acetylene and hydrogen as reactant gases. Samples were characterized using SEM and Raman spectroscopy. The work presented here aims to demonstrate the capability of the system to synthesize carbonaceous films and is starting point towards work on formation of carbon nanostructures. (author)

  8. Polymerization of Phenylacetylene-Based Monodendrons with Alkoxy Peripheral Groups and Oxygen/Nitrogen Permeation Behavior of Their Membranes

    Directory of Open Access Journals (Sweden)

    Takashi Kaneko

    2012-01-01

    Full Text Available Monodendron monomers with alkoxy peripheral groups were synthesized, and the focal point of monodendrons, terminal acetylene, was polymerized with rhodium catalyst to yield corresponding polydendrons with a high molecular weight. The polydendrons were soluble in common organic solvents and readily formed membranes. Oxygen permselectivity was improved in the polydendrons with a space-persistent dendritic crowd. It was found that the well-defined dendritic and rod-like structure of the polydendrons was useful for permselective membrane.

  9. Extraction atomic absorption determination of Cu, Ca, Mg and In in potassium chloride

    International Nuclear Information System (INIS)

    Telegin, G.F.; Chaplygin, V.I.

    1980-01-01

    Determination of microadmixtures of Cu, Ca, Mg, and In in potassium chloride by means of extraction separation of hydroxyquinolines of the elements determined by isoamyl alcohol from the sample basis is described. In is extracted in 10 min at pH 1.5-2.5% (100%). The extract is sprayed in the acetylene-air flame. Lower limits of the concentrations determined are 10 -5 -10 -7 %

  10. Trace elements in bottom sediments of the Barents Sea on the standard section "Kola Meridian"

    OpenAIRE

    Lapteva A. M.; Plotitsyna N. F.

    2017-01-01

    The levels of trace metals (Cu, Zn, Ni, Cr, Mn, Co, Pb, Cd, Hg) and arsenic (As) in samples of bottom sediments from the Barents Sea on eight stations of the standard section "Kola Meridian" have been investigated. Trace elements have been determined on atomic absorption spectrophotometer AA-6800 with mercury-hydride attachment HVG-1 of the company Shimadzu (Japan) by the methods of flaming (acetylene – air) and electrothermal atomization. Common and very toxic trace elements incl...

  11. Carbon chain molecules in interstellar clouds

    International Nuclear Information System (INIS)

    Winnewisser, G.; Walmsley, C.M.

    1979-01-01

    A survey of the distribution of long carbon chain molecules in interstellar clouds shows that their abundance is correlated. The various formation schemes for these molecules are discussed. It is concluded that the ion-molecule type formation mechanisms are more promising than their competitors. They have also the advantage of allowing predictions which can be tested by observations. Acetylene C 2 H 2 and diacetylene HCCCCH, may be very abundant in interstellar clouds. (Auth.)

  12. An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

    Directory of Open Access Journals (Sweden)

    Zhiyuan Ma

    2012-06-01

    Full Text Available Intramolecular inverse electron demand cycloadditions of isatin-derived 1,2,4-triazines with acetylenic dienophiles tethered by amidations or transesterifications proceed in excellent yields to produce lactam- or lactone-fused α-carbolines. Beginning with various isatins and alkynyl dienophiles, a pilot-scale library of eighty-eight α-carbolines was prepared by using this robust methodology for biological evaluation.

  13. A rapid method for determining tin and molybdenum in geological samples by flame atomic-absorption spectroscopy

    Science.gov (United States)

    Welsch, E.P.

    1985-01-01

    The proposed method uses a lithium metaborate fusion, dissolution of the fusion bead in 15% v v hydrochloric acid, extraction into a 4% solution of trioctylphosphine oxide in methyl isobutyl ketone, and aspiration into a nitrous oxide-acetylene flame. The limits of detection for tin and molybdenum are 1.0 and 0.5 ppm, respectively. Approximately 50 samples can be analysed per day. ?? 1985.

  14. Determination of calcium, copper, chromium, iron, magnesium, manganese, potassium, sodium and zinc in ethanol by atomic absorption spectrometry

    International Nuclear Information System (INIS)

    Fernandes, E.A.N.

    1981-01-01

    The direct determinacao of calcium, copper, chomium, iron, magnesium, manganese, potassium, sodium and zinc in ethanol by atomic absorption spectrometry with, air-acetylene flame is proposed. Effects of fuel/oxidant ratio, burner height and water content in the samples were investigated in detail. The method allows the determition of the elements with good precision (r.s.d. -1 for the elements tested. (author) [pt

  15. Controlled growth of carbon nanofibers using plasma enhanced chemical vapor deposition: Effect of catalyst thickness and gas ratio

    International Nuclear Information System (INIS)

    Saidin, M.A.R.; Ismail, A.F.; Sanip, S.M.; Goh, P.S.; Aziz, M.; Tanemura, M.

    2012-01-01

    The characteristics of carbon nanofibers (CNFs) grown, using direct current plasma enhanced chemical vapor deposition system reactor under various acetylene to ammonia gas ratios and different catalyst thicknesses were studied. Nickel/Chromium-glass (Ni/Cr-glass) thin film catalyst was employed for the growth of CNF. The grown CNFs were then characterized using Raman spectroscopy, field emission scanning electron microscopy and transmission electron microscopy (TEM). Raman spectroscopy showed that the Ni/Cr-glass with thickness of 15 nm and gas ratio acetylene to ammonia of 1:3 produced CNFs with the lowest I D /I G value (the relative intensity of D-band to G-band). This indicated that this catalyst thickness and gas ratio value is the optimum combination for the synthesis of CNFs under the conditions studied. TEM observation pointed out that the CNFs produced have 104 concentric walls and the residual catalyst particles were located inside the tubes of CNFs. It was also observed that structural morphology of the grown CNFs was influenced by acetylene to ammonia gas ratio and catalyst thickness.

  16. Controlled growth of carbon nanofibers using plasma enhanced chemical vapor deposition: Effect of catalyst thickness and gas ratio

    Energy Technology Data Exchange (ETDEWEB)

    Saidin, M.A.R. [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Ismail, A.F., E-mail: afauzi@utm.my [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Sanip, S.M.; Goh, P.S.; Aziz, M. [Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor Bahru (Malaysia); Tanemura, M. [Department of Frontier Material, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan)

    2012-01-31

    The characteristics of carbon nanofibers (CNFs) grown, using direct current plasma enhanced chemical vapor deposition system reactor under various acetylene to ammonia gas ratios and different catalyst thicknesses were studied. Nickel/Chromium-glass (Ni/Cr-glass) thin film catalyst was employed for the growth of CNF. The grown CNFs were then characterized using Raman spectroscopy, field emission scanning electron microscopy and transmission electron microscopy (TEM). Raman spectroscopy showed that the Ni/Cr-glass with thickness of 15 nm and gas ratio acetylene to ammonia of 1:3 produced CNFs with the lowest I{sub D}/I{sub G} value (the relative intensity of D-band to G-band). This indicated that this catalyst thickness and gas ratio value is the optimum combination for the synthesis of CNFs under the conditions studied. TEM observation pointed out that the CNFs produced have 104 concentric walls and the residual catalyst particles were located inside the tubes of CNFs. It was also observed that structural morphology of the grown CNFs was influenced by acetylene to ammonia gas ratio and catalyst thickness.

  17. A Green Process for High-Concentration Ethylene and Hydrogen Production from Methane in a Plasma-Followed-by-Catalyst Reactor

    International Nuclear Information System (INIS)

    Wang Kangjun; Li Xiaosong; Zhu Aimin

    2011-01-01

    A green process for the oxygen-free conversion of methane to high-concentration ethylene and hydrogen in a plasma-followed-by-catalyst (PFC) reactor is presented. Without any catalysts and with pure methane used as the feed gas, a stable kilohertz spark discharge leads to an acetylene yield of 64.1%, ethylene yield of 2.5% and hydrogen yield of 59.0% with 80.0% of methane conversion at a methane flow rate of 50 cm 3 /min and a specific input energy of 38.4 kJ/L. In the effluent gas from a stable kilohertz spark discharge reactor, the concentrations of acetylene, ethylene and hydrogen were 18.1%, 0.7% and 66.9%, respectively. When catalysts Pd-Ag/SiO 2 were employed in the second stage with discharge conditions same as in the case of plasma alone, the PFC reactor provides an ethylene yield of 52.1% and hydrogen yield of 43.4%. The concentrations of ethylene and hydrogen in the effluent gas from the PFC reactor were found to be as high as 17.1% and 62.6%, respectively. Moreover, no acetylene was detected in the effluent gas. This means that a high concentration of ethylene and oxygen-free hydrogen can be co-produced directly from methane in the PFC reactor.

  18. Fabrication of nanostructured clay-carbon nanotube hybrid nanofiller by chemical vapour deposition

    Energy Technology Data Exchange (ETDEWEB)

    Manikandan, Dhanagopal, E-mail: dmani_cat@yahoo.co.in [Department of Materials Engineering, Faculty of Engineering, University of Concepcion, Concepcion (Chile); Mangalaraja, Ramalinga Viswanathan, E-mail: mangal@udec.cl [Department of Materials Engineering, Faculty of Engineering, University of Concepcion, Concepcion (Chile); Siddheswaran, Rajendran [Department of Materials Engineering, Faculty of Engineering, University of Concepcion, Concepcion (Chile); Avila, Ricardo E. [Personal Dosimetry Section, Chilean Nuclear Energy Commission, Santiago (Chile); Ananthakumar, Solaiappan [Materials and Minerals Division, National Institute for Interdisciplinary Science and Technology (NIIST), Trivandrum, Kerala (India)

    2012-03-01

    Growth of multiwalled carbon nanotube (CNT) assemblies by chemical vapour decomposition (CVD) technique was achieved through decomposition of acetylene using iron impregnated montmorillonite (MM) catalysts. Various amounts of iron loaded montmorillonite catalysts were prepared by wet impregnation method and calcined at 450 Degree-Sign C. The catalysts were subjected to X-ray diffraction (XRD) and surface area analyses. Acetylene decomposition at a feed ratio of N{sub 2}:H{sub 2}:C{sub 2}H{sub 2} = 1:1:0.18 was conducted in the presence of iron impregnated montmorillonite catalysts in the CVD reactor for the growth of CNT structures. The role of Fe-activated clay catalyst on the formation of CNT structures has been systematically examined at various temperatures and correlated with the morphological features of CNTs. Catalyst assisted acetylene decomposition results the formation of different carbon nanostructures such as nanotubes, nanofibres and nanoflakes. These clay-CNT products were characterised for their morphological, thermal, qualitative and quantitative analyses. The morphological variations of CNT assemblies reveal Fe-montmorillonite catalysts have high selectivity at given reaction conditions. Thermogravimetric and Raman spectral analyses prove that the CNTs contain a good crystallanity and less structural defects.

  19. Structure of MoCN films deposited by cathodic arc evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Gilewicz, A., E-mail: adam.gilewicz@tu.koszalin.pl [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland); Jedrzejewski, R.; Kochmanska, A.E. [West Pomeranian University of Technology Szczecin, Faculty of Mechanical Engineering and Mechatronics, 19 Piastów Ave., 70-313 Szczecin (Poland); Warcholinski, B. [Koszalin University of Technology, Faculty of Technology and Education, Sniadeckich 2, 75-453 Koszalin (Poland)

    2015-02-27

    Molybdenum carbonitride (MoCN) coatings were deposited onto HS6-5-2 steel substrate using pure Mo targets in mixed acetylene and nitrogen atmosphere by cathodic arc evaporation. The structural properties of MoCN coatings with different carbon contents (as an effect of the C{sub 2}H{sub 2} flow rate) were investigated systematically. Phase and chemical composition evolution of the coatings were characterized both by the glancing angle of X-ray diffraction (XRD) and wavelength dispersive spectrometry, respectively. These analyses have been supplemented by estimates of grain sizes and stress in the coatings. The XRD results show that the increase in acetylene flow rate causes the formation of molybdenum carbide (MoC) hexagonal phase in the coatings, a reduction of grain size and an increase in internal stress. - Highlights: • MoN and MoCN coatings were deposited by cathodic arc evaporation in nitrogen atmosphere. • MoCN coatings were formed using different acetylene flow rates. • Phase composition evolution was observed. • Crystallite size and stress were calculated.

  20. Vibration atomic layer deposition for conformal nanoparticle coating

    Energy Technology Data Exchange (ETDEWEB)

    Park, Suk Won; Woo Kim, Jun; Jong Choi, Hyung; Hyung Shim, Joon, E-mail: shimm@korea.ac.kr [School of Mechanical Engineering, Korea University, Seoul 136-701 (Korea, Republic of)

    2014-01-15

    A vibration atomic layer deposition reactor was developed for fabricating a conformal thin-film coating on nanosize particles. In this study, atomic layer deposition of 10–15-nm-thick Al{sub 2}O{sub 3} films was conducted on a high-surface-area acetylene black powder with particle diameters of 200–250 nm. Intense vibration during the deposition resulted in the effective separation of particles, overcoming the interparticle agglomeration force and enabling effective diffusion of the precursor into the powder chunk; this phenomenon led to the formation of a conformal film coating on the nanopowder particles. It was also confirmed that the atomic layer deposition Al{sub 2}O{sub 3} films initially grew on the high-surface-area acetylene black powder particles as discrete islands, presumably because chemisorption of the precursor and water occurred only on a few sites on the high-surface-area acetylene black powder surface. Relatively sluggish growth of the films during the initial atomic layer deposition cycles was identified from composition analysis.

  1. Friction and wear performance of diamond-like carbon films grown in various source gas plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, A.; Nilufer, I.B.; Eryilmaz, O.L.; Beschliesser, M.; Fenske, G.R. [Argonne National Lab., IL (United States). Energy Technology Div.

    1999-11-01

    In this study, we investigated the effects of various source gases (methane, ethane, ethylene, and acetylene) on the friction and wear performance of diamond-like carbon (DLC) films prepared in a plasma-enhanced chemical vapor deposition (PECVD) system. Films were deposited on AISI H13 steel substrates and tested in a pin-on-disk machine against DLC-coated M50 balls in dry nitrogen. We found a close correlation between friction coefficient and source gas composition. Specifically, films grown in source gases with higher hydrogen-to-carbon ratios exhibited lower friction coefficients and a higher wear resistance than films grown in source gases with lower hydrogen-to-carbon (H/C) ratios. The lowest friction coefficient (0.014) was achieved with a film derived from methane with an H/C ratio of 4, whereas the coefficient of films derived from acetylene (H/C=1) was 0.15. Similar correlations were observed for wear rates. Specifically, films derived from gases with lower H/C values were worn out, and the substrate material was exposed, whereas films from methane and ethane remained intact and wore at rates that were almost two orders of magnitude lower than films obtained from acetylene. (orig.)

  2. Optimization, Yield Studies and Morphology of WO3Nano-Wires Synthesized by Laser Pyrolysis in C2H2and O2Ambients—Validation of a New Growth Mechanism

    Directory of Open Access Journals (Sweden)

    Sideras-Haddad E

    2008-01-01

    Full Text Available Abstract Laser pyrolysis has been used to synthesize WO3nanostructures. Spherical nano-particles were obtained when acetylene was used to carry the precursor droplet, whereas thin films were obtained at high flow-rates of oxygen carrier gas. In both environments WO3nano-wires appear only after thermal annealing of the as-deposited powders and films. Samples produced under oxygen carrier gas in the laser pyrolysis system gave a higher yield of WO3nano-wires after annealing than the samples which were run under acetylene carrier gas. Alongside the targeted nano-wires, the acetylene-ran samples showed trace amounts of multi-walled carbon nano-tubes; such carbon nano-tubes are not seen in the oxygen-processed WO3nano-wires. The solid–vapour–solid (SVS mechanism [B. Mwakikunga et al., J. Nanosci. Nanotechnol., 2008] was found to be the possible mechanism that explains the manner of growth of the nano-wires. This model, based on the theory from basic statistical mechanics has herein been validated by length-diameter data for the produced WO3nano-wires.

  3. Experimental study on a comparison of typical premixed combustible gas-air flame propagation in a horizontal rectangular closed duct.

    Science.gov (United States)

    Jin, Kaiqiang; Duan, Qiangling; Liew, K M; Peng, Zhongjing; Gong, Liang; Sun, Jinhua

    2017-04-05

    Research surrounding premixed flame propagation in ducts has a history of more than one hundred years. Most previous studies focus on the tulip flame formation and flame acceleration in pure gas fuel-air flame. However, the premixed natural gas-air flame may show different behaviors and pressure dynamics due to its unique composition. Natural gas, methane and acetylene are chosen here to conduct a comparison study on different flame behaviors and pressure dynamics, and to explore the influence of different compositions on premixed flame dynamics. The characteristics of flame front and pressure dynamics are recorded using high-speed schlieren photography and a pressure transducer, respectively. The results indicate that the compositions of the gas mixture greatly influence flame behaviors and pressure. Acetylene has the fastest flame tip speed and the highest pressure, while natural gas has a faster flame tip speed and higher pressure than methane. The Bychkov theory for predicting the flame skirt motion is verified, and the results indicate that the experimental data coincide well with theory in the case of equivalence ratios close to 1.00. Moreover, the Bychkov theory is able to predict flame skirt motion for acetylene, even outside of the best suitable expansion ratio range of 6

  4. Modeling the chemistry of plasma polymerization using mass spectrometry.

    Science.gov (United States)

    Ihrig, D F; Stockhaus, J; Scheide, F; Winkelhake, Oliver; Streuber, Oliver

    2003-04-01

    The goal of the project is a solvent free painting shop. The environmental technologies laboratory is developing processes of plasma etching and polymerization. Polymerized thin films are first-order corrosion protection and primer for painting. Using pure acetylene we get very nice thin films which were not bonded very well. By using air as bulk gas it is possible to polymerize, in an acetylene plasma, well bonded thin films which are stable first-order corrosion protections and good primers. UV/Vis spectroscopy shows nitrogen oxide radicals in the emission spectra of pure nitrogen and air. But nitrogen oxide is fully suppressed in the presence of acetylene. IR spectroscopy shows only C=O, CH(2) and CH(3) groups but no nitrogen species. With the aid of UV/Vis spectra and the chemistry of ozone formation it is possible to define reactive traps and steps, molecule depletion and processes of proton scavenging and proton loss. Using a numerical model it is possible to evaluate these processes and to calculate theoretical mass spectra. Adjustment of theoretical mass spectra to real measurements leads to specific channels of polymerization which are driven by radicals especially the acetyl radical. The estimated theoretical mass spectra show the specific channels of these chemical processes. It is possible to quantify these channels. This quantification represents the mass flow through this chemical system. With respect to these chemical processes it is possible to have an idea of pollutant production processes.

  5. Novel technique for coal pyrolysis and hydrogenation product analysis

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferle, L.D.

    1992-01-01

    This report covers the last quarter of the last year of the three-year grant period. In the final project year, we concentrated on the pyrolysis and oxidative pyrolysis of large hydrocarbons and mixtures of large and small hydrocarbons in order to develop the VUV-MS technique for compounds more representative of those in coal pyrolysis applications. Special focus was directed at the pyrolysis and oxidative pyrolysis of benzene and benzene acetylene mixtures. The acetylene/benzene mixtures were used to gain a better understanding of the mechanisms of molecular growth in such systems specifically to look at the kinetics of aryl-aryl reactions as opposed to small molecule addition to phenyl radicals. Sarofim and coworkers at MIT have recently demonstrated the importance of these reactions in coal processing environments. In the past, the growth mechanism for the formation of midsized PAH has been postulated to involve primarily successive acetylene additions to phenyl-type radicals, our work confmns this as an important mechanism especially for smaller PAH but also investigates conditions where biaryl formation can play an important role in higher hydrocarbon formation.

  6. Novel technique for coal pyrolysis and hydrogenation product analysis. Quarterly report, June 1, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Pfefferle, L.D.

    1992-12-31

    This report covers the last quarter of the last year of the three-year grant period. In the final project year, we concentrated on the pyrolysis and oxidative pyrolysis of large hydrocarbons and mixtures of large and small hydrocarbons in order to develop the VUV-MS technique for compounds more representative of those in coal pyrolysis applications. Special focus was directed at the pyrolysis and oxidative pyrolysis of benzene and benzene acetylene mixtures. The acetylene/benzene mixtures were used to gain a better understanding of the mechanisms of molecular growth in such systems specifically to look at the kinetics of aryl-aryl reactions as opposed to small molecule addition to phenyl radicals. Sarofim and coworkers at MIT have recently demonstrated the importance of these reactions in coal processing environments. In the past, the growth mechanism for the formation of midsized PAH has been postulated to involve primarily successive acetylene additions to phenyl-type radicals, our work confmns this as an important mechanism especially for smaller PAH but also investigates conditions where biaryl formation can play an important role in higher hydrocarbon formation.

  7. Exploring possible reaction pathways for the o-atom transfer reactions to unsaturated substrates catalyzed by a [Ni-NO2 ] ↔ [Ni-NO] redox couple using DFT methods.

    Science.gov (United States)

    Tsipis, Athanassios C

    2017-07-15

    The (nitro)(N-methyldithiocarbamato)(trimethylphospane)nickel(II), [Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] complex catalyses efficiently the O-atom transfer reactions to CO and acetylene. Energetically feasible sequence of elementary steps involved in the catalytic cycle of the air oxidation of CO and acetylene are proposed promoted by the Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] ↔ Ni(NO 2 )(S 2 CNHMe)(PMe 3 ) redox couple using DFT methods both in vacuum and dichloromethane solutions. The catalytic air oxidation of HC≡CH involves formation of a five-member metallacycle intermediate, via a [3 + 2] cyclo-addition reaction of HC≡CH to the Ni-N = O moiety of the Ni(NO 2 )(S 2 CNHMe)(PMe 3 )] complex, followed by a β H-atom migration toward the C α carbon atom of the coordinated acetylene and release of the oxidation product (ketene). The geometric and energetic reaction profile for the reversible [Ni( κN1-NO 2 )(S 2 CNHMe)(PMe 3 )] ⇌ [Ni( κO,O2-ONO)(S 2 CNHMe)(PMe 3 )] linkage isomerization has also been modeled by DFT calculations. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  8. Fabrication of nanostructured clay-carbon nanotube hybrid nanofiller by chemical vapour deposition

    International Nuclear Information System (INIS)

    Manikandan, Dhanagopal; Mangalaraja, Ramalinga Viswanathan; Siddheswaran, Rajendran; Avila, Ricardo E.; Ananthakumar, Solaiappan

    2012-01-01

    Growth of multiwalled carbon nanotube (CNT) assemblies by chemical vapour decomposition (CVD) technique was achieved through decomposition of acetylene using iron impregnated montmorillonite (MM) catalysts. Various amounts of iron loaded montmorillonite catalysts were prepared by wet impregnation method and calcined at 450 °C. The catalysts were subjected to X-ray diffraction (XRD) and surface area analyses. Acetylene decomposition at a feed ratio of N 2 :H 2 :C 2 H 2 = 1:1:0.18 was conducted in the presence of iron impregnated montmorillonite catalysts in the CVD reactor for the growth of CNT structures. The role of Fe-activated clay catalyst on the formation of CNT structures has been systematically examined at various temperatures and correlated with the morphological features of CNTs. Catalyst assisted acetylene decomposition results the formation of different carbon nanostructures such as nanotubes, nanofibres and nanoflakes. These clay-CNT products were characterised for their morphological, thermal, qualitative and quantitative analyses. The morphological variations of CNT assemblies reveal Fe-montmorillonite catalysts have high selectivity at given reaction conditions. Thermogravimetric and Raman spectral analyses prove that the CNTs contain a good crystallanity and less structural defects.

  9. IR-UV double resonance spectroscopic investigation of phenylacetylene-alcohol complexes. Alkyl group induced hydrogen bond switching.

    Science.gov (United States)

    Singh, Prashant Chandra; Patwari, G Naresh

    2008-06-12

    The electronic transitions of phenylacetylene complexes with water and trifluoroethanol are shifted to the blue, while the corresponding transitions for methanol and ethanol complexes are shifted to the red relative to the phenylacetylene monomer. Fluorescence dip infrared (FDIR) spectra in the O-H stretching region indicate that, in all the cases, phenylacetylene is acting as a hydrogen bond acceptor to the alcohols. The FDIR spectrum in the acetylenic C-H stretching region shows Fermi resonance bands for the bare phenylacetylene, which act as a sensitive tool to probe the intermolecular structures. The FDIR spectra reveal that water and trifluoroethanol interact with the pi electron density of the acetylene C-C triple bond, while methanol and ethanol interact with the pi electron density of the benzene ring. It can be inferred that the hydrogen bonding acceptor site on phenylacetylene switches from the acetylene pi to the benzene pi with lowering in the partial charge on the hydrogen atom of the OH group. The most significant finding is that the intermolecular structures of water and methanol complexes are notably distinct, which, to the best of our knowledge, this is first such observation in the case of complexes of substituted benzenes.

  10. Carbon-based sputtered coatings for enhanced chitosan-based films properties

    Science.gov (United States)

    Fernandes, C.; Calderon V., S.; Ballesteros, Lina F.; Cerqueira, Miguel A.; Pastrana, L. M.; Teixeira, José A.; Ferreira, P. J.; Carvalho, S.

    2018-03-01

    In order to make bio-based packaging materials competitive in comparison to petroleum-based one, some of their properties need to be improved, among which gas permeability is of crucial importance. Thus, in this work, carbon-based coatings were applied on chitosan-based films by radiofrequency reactive magnetron sputtering aiming to improve their barrier properties. Chemical and morphological properties were evaluated in order to determine the effect of the coatings on the chemical structure, surface hydrophobicity and barrier properties of the system. Chemical analysis, performed by electron energy loss spectroscopy and Fourier transform infrared spectroscopy, suggests similar chemical characteristics among all coatings although higher incorporation of hydrogen as the acetylene flux increases was observed. On the other hand, scanning transmission electron microscopy revealed that the porosity of the carbon layer can be tailored by the acetylene flux. More importantly, the chitosan oxygen permeability showed a monotonic reduction as a function of the acetylene flux. This study opens up new opportunities to apply nanostructured coatings on bio-based polymer for enhanced oxygen barrier properties.

  11. Nitrogen fixation associated with development and localization of mixed populations of Cellulomonas species and Azospirillium brasilense grown on cellulose or wheat straw

    Energy Technology Data Exchange (ETDEWEB)

    Halsall, D.M.; Goodchild, D.J.

    1986-04-01

    Mixed cultures of Cellulomonas sp. and Azospirillum brasilense were grown with straw or cellulose as the carbon source under conditions favoring the fixation of atmospheric nitrogen. Rapid increases in cell numbers, up to 10/sup 9/ cells per g of substrate, were evident after 4 and 5 days of incubation at 30 degrees C for cellulose and straw, respectively. Nitrogen fixation (detected by acetylene reduction measured on parallel cultures) commenced after 2 and 4 days of incubation for straw and cellulose, respectively, and continued for the duration of the experiment. Pure cultures of Cellulomonas sp. showed an increase in cell numbers, but CO/sub 2/ production was low, and acetylene reduction was not detected on either cellulose or straw. Pure cultures of A. brasilense on cellulose showed an inital increase in cell numbers (10/sup 7/ cells per g of substrate) over 4 days, followed by a decline presumably caused by the exhaustion of available carbon substrate. On straw, A. brasilense increased to 10/sup 9/ cells per g of substrate over 5 days and then declined slowly; this growth was accompanied by acetylene reduction. Scanning electron micrographs of straw incubated with a mixture under the above conditions for 8 days showed cells of both species in close proximity to each other. Evidence was furnished that the close spatial relatioship of cells from the two species facilitated the mutally beneficial association between them and thus increased the efficiency with which the products of straw breakdown were used for nitrogen fixation. 17 references.

  12. Role of carbon atoms in the remote plasma deposition of hydrogenated amorphous carbon

    International Nuclear Information System (INIS)

    Benedikt, J.; Wisse, M.; Woen, R.V.; Engeln, R.; Sanden, M.C.M. van de

    2003-01-01

    The aim of this article is to determine the role of carbon atoms in the growth of hydrogenated amorphous carbon (a-C:H) films by means of an argon/acetylene expanding thermal plasma. Cavity ring down absorption spectroscopy is used to detect metastable carbon atoms by probing the 1s 2 2s 2 2p 3s 1 P 1 2 2s 2 2p 2 1 S 0 electronic transition. In addition to absorption measurements, the emission of the same transition is monitored by means of optical emission spectroscopy. These two measurements provide information about the local production of the C atoms and about their reactivity in the gas phase. It will be shown that under growth conditions in an Ar/C 2 H 2 expanding thermal plasma, the metastable carbon density is also representative for the ground state carbon density. From obtained results it is concluded that the carbon atoms react rapidly with acetylene in the gas phase and therefore their contribution to the growth of hard diamond-like a-C:H films can be neglected. Only at low acetylene flows, the condition when soft polymer-like films are deposited, carbon atoms are detected close to the substrate and can possibly contribute to the film growth

  13. Development of dual-broadband rotational CARS for combustion diagnostics

    Energy Technology Data Exchange (ETDEWEB)

    Bood, Joakim

    2000-06-01

    The present thesis concerns development and application of dual-broadband rotational coherent anti-Stokes Raman spectroscopy (DB-RCARS) for temperature and species concentration measurements in combustion processes. Both fundamental development of the technique, including experimental as well as modelling results, and measurements in practical combustion devices were conducted. A code for calculation of rotational CARS spectra of pure acetylene as well as mixtures of acetylene and nitrogen was developed. Using this code, temperatures and relative acetylene to nitrogen concentrations were evaluated from DB-RCARS measurements in pure acetylene and different acetylene/nitrogen mixtures. Moreover, rotational CARS spectra of dimethyl-ether (DME) have been analyzed. A powerful tool for simultaneous temperature and multiple species concentration measurements was developed by combining rotational CARS with vibrational CARS. The concept was demonstrated for measurements of temperature, oxygen, and carbon monoxide concentrations simultaneously in a premixed sooting ethene/air flame. Rotational CARS spectra of nitrogen at very high pressures (0.1-44 MPa) at room temperature were investigated. The experimental spectra were compared with calculated spectra using different Raman linewidth models. The results indicate some shortcomings in the present model, basically the density calculation and neglecting overlapping effects between adjacent spectral lines. A new method for CARS measurements in several spatially separated points simultaneously was developed. By using DB-RCARS the method was demonstrated for quantitative measurements of profiles of temperatures and oxygen concentrations. An atomic filter for rejection of stray light was developed. The filter was shown to efficiently reject stray light from the narrowband laser without affecting the shape of the rotational CARS spectrum or causing any signal losses. Within an interdisciplinary project intended to increase the

  14. Oxy-gasoline torch. Innovative technology summary report

    International Nuclear Information System (INIS)

    1998-12-01

    Under the deactivation and decommissioning (D and D) Implementation Plan of the US Department of Energy's (DOE) Fernald Environmental Management Project (FEMP), non-recyclable process components and debris that are removed from buildings undergoing D and D are disposed of in an on-site disposal facility (OSDF). Critical to the design and operation of the FEMP's OSDF are provisions to protect against subsidence of the OSDF's cap. Subsidence of the cap could occur if void spaces within the OSDF were to collapse under the overburden of debris and the OSDF cap. Subsidence may create significant depressions in the OSDF's cap in which rainwater could collect and eventually seep into the OSDF. To minimize voids in the FEMP's OSDF, large metallic components are cut into smaller segments that can be arranged more compactly when placed in the OSDF. Component segmentation using an oxy-acetylene cutting torch was the baseline approach used by the FEMP's D and D contractor on Plant 1, Babcock and Wilcox (B and W) Services, Inc., for the dismantlement and size-reduction of large metal components. Although this technology has performed satisfactorily, improvements are sought in the areas of productivity, airborne contamination, safety, and cost. This demonstration investigated the feasibility of using an oxy-gasoline torch as an alternative to the baseline oxy-acetylene torch for segmenting D and D components. This report provides a comparative analysis of the cost and performance of the baseline oxy-acetylene torch currently used by B and W Services, Inc., and the innovative oxy-gasoline torch

  15. Effects of gasoline components on MTBE and TBA cometabolism by Mycobacterium austroafricanum JOB5.

    Science.gov (United States)

    House, Alan J; Hyman, Michael R

    2010-07-01

    In this study we have examined the effects of individual gasoline hydrocarbons (C(5-10,12,14) n-alkanes, C(5-8) isoalkanes, alicyclics [cyclopentane and methylcyclopentane] and BTEX compounds [benzene, toluene, ethylbenzene, m-, o-, and p-xylene]) on cometabolism of methyl tertiary butyl ether (MTBE) and tertiary butyl alcohol (TBA) by Mycobacterium austroafricanum JOB5. All of the alkanes tested supported growth and both MTBE and TBA oxidation. Growth on C(5-8) n-alkanes and isoalkanes was inhibited by acetylene whereas growth on longer chain n-alkanes was largely unaffected by this gas. However, oxidation of both MTBE and TBA by resting cells was consistently inhibited by acetylene, irrespective of the alkane used as growth-supporting substrate. A model involving two separate but co-expressed alkane-oxidizing enzyme systems is proposed to account for these observations. Cyclopentane, methylcyclopentane, benzene and ethylbenzene did not support growth but these compounds all inhibited MTBE and TBA oxidation by alkane-grown cells. In the case of benzene, the inhibition was shown to be due to competitive interactions with both MTBE and TBA. Several aromatic compounds (p-xylene > toluene > m-xylene) did support growth and cells previously grown on these substrates also oxidized MTBE and TBA. Low concentrations of toluene (TBA oxidation by alkane-grown cells whereas higher concentrations were inhibitory. The effects of acetylene suggest strain JOB5 also has two distinct toluene-oxidizing activities. These results have been discussed in terms of their impact on our understanding of MTBE and TBA cometabolism and the enzymes involved in these processes in mycobacteria and other bacteria.

  16. Applications of a Mid-IR Quantum Cascade Laser in Gas Sensing Research

    KAUST Repository

    Sajid, Muhammad Bilal

    2015-05-01

    Laser absorption based sensors are extensively used in a variety of gas sensing areas such as combustion, atmospheric research, human breath analysis, and high resolution infrared spectroscopy. Quantum cascade lasers have recently emerged as high resolution, high power laser sources operating in mid infrared region and can have wide tunability range. These devices provide an opportunity to access stronger fundamental and combination vibrational bands located in mid infrared region than previously accessible weaker overtone vibrational bands located in near infrared region. Spectroscopic region near 8 µm contains strong vibrational bands of methane, acetylene, hydrogen peroxide, water vapor and nitrous oxide. These molecules have important applications in a wide range of applications. This thesis presents studies pertaining to spectroscopy and combustion applications. Advancements in combustion research are imperative to achieve lower emissions and higher efficiency in practical combustion devices such as gas turbines and engines. Accurate chemical kinetic models are critical to achieve predictive models which contain several thousand reactions and hundreds of species. These models need highly reliable experimental data for validation and improvements. Shock tubes are ideal devices to obtain such information. A shock tube is a homogenous, nearly constant volume, constant pressure, adiabatic and 0-D reactor. In combination with laser absorption sensors, shock tubes can be used to measure reaction rates and species time histories of several intermediates and products formed during pyrolysis and oxidation of fuels. This work describes measurement of the decomposition rate of hydrogen peroxide which is an important intermediate species controlling reactivity of combustion system in the intermediate temperature range. Spectroscopic parameters (linestrengths, broadening coefficients and temperature dependent coefficients) are determined for various transitions of

  17. Millimeter-wave spectroscopy of CrC (X(3)Σ(-)) and CrCCH (X̃ (6)Σ(+)): Examining the chromium-carbon bond.

    Science.gov (United States)

    Min, J; Ziurys, L M

    2016-05-14

    Pure rotational spectroscopy of the CrC (X(3)Σ(-)) and CrCCH (X̃ (6)Σ(+)) radicals has been conducted using millimeter/sub-millimeter direct absorption methods in the frequency range 225-585 GHz. These species were created in an AC discharge of Cr(CO)6 and either methane or acetylene, diluted in argon. Spectra of the CrCCD were also recorded for the first time using deuterated acetylene as the carbon precursor. Seven rotational transitions of CrC were measured, each consisting of three widely spaced, fine structure components, arising from spin-spin and spin-rotation interactions. Eleven rotational transitions were recorded for CrCCH and five for CrCCD; each transition in these cases was composed of a distinct fine structure sextet. These measurements confirm the respective (3)Σ(-) and (6)Σ(+) ground electronic states of these radicals, as indicated from optical studies. The data were analyzed using a Hund's case (b) Hamiltonian, and rotational, spin-spin, and spin-rotation constants have been accurately determined for all three species. The spectroscopic parameters for CrC were significantly revised from previous optical work, while those for CrCCH are in excellent agreement; completely new constants were established for CrCCD. The chromium-carbon bond length for CrC was calculated to be 1.631 Å, while that in CrCCH was found to be rCr-C = 1.993 Å - significantly longer. This result suggests that a single Cr-C bond is present in CrCCH, preserving the acetylenic structure of the ligand, while a triple bond exists in CrC. Analysis of the spin constants suggests that CrC has a nearby excited (1)Σ(+) state lying ∼16 900 cm(-1) higher in energy, and CrCCH has a (6)Π excited state with E ∼ 4800 cm(-1).

  18. Use of aliphatic n-alkynes to discriminate soil nitrification activities of ammonia-oxidizing thaumarchaea and bacteria.

    Science.gov (United States)

    Taylor, Anne E; Vajrala, Neeraja; Giguere, Andrew T; Gitelman, Alix I; Arp, Daniel J; Myrold, David D; Sayavedra-Soto, Luis; Bottomley, Peter J

    2013-11-01

    Ammonia (NH3)-oxidizing bacteria (AOB) and thaumarchaea (AOA) co-occupy most soils, yet no short-term growth-independent method exists to determine their relative contributions to nitrification in situ. Microbial monooxygenases differ in their vulnerability to inactivation by aliphatic n-alkynes, and we found that NH3 oxidation by the marine thaumarchaeon Nitrosopumilus maritimus was unaffected during a 24-h exposure to ≤ 20 μM concentrations of 1-alkynes C8 and C9. In contrast, NH3 oxidation by two AOB (Nitrosomonas europaea and Nitrosospira multiformis) was quickly and irreversibly inactivated by 1 μM C8 (octyne). Evidence that nitrification carried out by soilborne AOA was also insensitive to octyne was obtained. In incubations (21 or 28 days) of two different whole soils, both acetylene and octyne effectively prevented NH4(+)-stimulated increases in AOB population densities, but octyne did not prevent increases in AOA population densities that were prevented by acetylene. Furthermore, octyne-resistant, NH4(+)-stimulated net nitrification rates of 2 and 7 μg N/g soil/day persisted throughout the incubation of the two soils. Other evidence that octyne-resistant nitrification was due to AOA included (i) a positive correlation of octyne-resistant nitrification in soil slurries of cropped and noncropped soils with allylthiourea-resistant activity (100 μM) and (ii) the finding that the fraction of octyne-resistant nitrification in soil slurries correlated with the fraction of nitrification that recovered from irreversible acetylene inactivation in the presence of bacterial protein synthesis inhibitors and with the octyne-resistant fraction of NH4(+)-saturated net nitrification measured in whole soils. Octyne can be useful in short-term assays to discriminate AOA and AOB contributions to soil nitrification.

  19. Inactivation of Toluene 2-Monooxygenase in Burkholderia cepacia G4 by Alkynes

    Science.gov (United States)

    Yeager, Chris M.; Bottomley, Peter J.; Arp, Daniel J.; Hyman, Michael R.

    1999-01-01

    High concentrations of acetylene (10 to 50% [vol/vol] gas phase) were required to inhibit the growth of Burkholderia cepacia G4 on toluene, while 1% (vol/vol) (gas phase) propyne or 1-butyne completely inhibited growth. Low concentrations of longer-chain alkynes (C5 to C10) were also effective inhibitors of toluene-dependent growth, and 2- and 3-alkynes were more potent inhibitors than their 1-alkyne counterparts. Exposure of toluene-grown B. cepacia G4 to alkynes resulted in the irreversible loss of toluene- and o-cresol-dependent O2 uptake activities, while acetate- and 3-methylcatechol-dependent O2 uptake activities were unaffected. Toluene-dependent O2 uptake decreased upon the addition of 1-butyne in a concentration- and time-dependent manner. The loss of activity followed first-order kinetics, with apparent rate constants ranging from 0.25 min−1 to 2.45 min−1. Increasing concentrations of toluene afforded protection from the inhibitory effects of 1-butyne. Furthermore, oxygen, supplied as H2O2, was required for inhibition by 1-butyne. These results suggest that alkynes are specific, mechanism-based inactivators of toluene 2-monooxygenase in B. cepacia G4, although the simplest alkyne, acetylene, was relatively ineffective compared to longer alkynes. Alkene analogs of acetylene and propyne—ethylene and propylene—were not inactivators of toluene 2-monooxygenase activity in B. cepacia G4 but were oxidized to their respective epoxides, with apparent Ks and Vmax values of 39.7 μM and 112.3 nmol min−1 mg of protein−1 for ethylene and 32.3 μM and 89.2 nmol min−1 mg of protein−1 for propylene. PMID:9925593

  20. Pivotal role of water in terminating enzymatic function: a density functional theory study of the mechanism-based inactivation of cytochromes P450.

    Science.gov (United States)

    Hirao, Hajime; Cheong, Zhi Hao; Wang, Xiaoqing

    2012-07-12

    The importance of the mechanism-based inactivation (MBI) of enzymes, which has a variety of physiological effects and therapeutic implications, has been garnering appreciation. Density functional theory calculations were undertaken to gain a clear understanding of the MBI of a cytochrome P450 enzyme (CYP2B4) by tert-butylphenylacetylene (tBPA). The results of calculations suggest that, in accordance with previous proposals, the reaction proceeds via a ketene-type metabolic intermediate. Once an oxoiron(IV) porphyryn π-cation radical intermediate (compound I) of P450 is generated at the heme reaction site, ketene formation is facile, as the terminal acetylene of tBPA can form a C-O bond with the oxo unit of compound I with a relatively low reaction barrier (14.1 kcal/mol). Unexpectedly, it was found that the ketene-type intermediate was not very reactive. Its reaction with the hydroxyl group of a threonine (Thr302) to form an ester bond required a substantial barrier (38.2 kcal/mol). The high barrier disfavored the mechanism by which these species react directly. However, the introduction of a water molecule in the reaction center led to its active participation in the reaction. The water was capable of donating its proton to the tBPA molecule, while accepting the proton of threonine. This water-mediated mechanism lowered the reaction barrier for the formation of an ester bond by about 20 kcal/mol. Therefore, our study suggests that a water molecule, which can easily gain access to the threonine residue through the proton-relay channel, plays a critical role in enhancing the covalent modification of threonine by terminal acetylene compounds. Another type of MBI by acetylenes, N-alkylation of the heme prosthetic group, was less favorable than the threonine modification pathway.