WorldWideScience

Sample records for butenes

  1. Structure and Mechanical Properties of Ethylene-butene Copolymers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The crystallinity of ethylene-butene copolymers prepared by copolymerization of ethylene and butene in the presence of a new highly active catalyst was studied by means of DSC, WAXD and DMA. The results show that the melting temperature, the crystallinity and the crystallite size decreased with increasing the content of butene in the copolymers. The copolymers have a high degree of branching, the butene segments are mainly in the amorphous regions of the copolymers, while the polyethylene sequence forms crystal phase acting as crosslinking bondage between the molecules at room temperature. The ethylene-butene copolymers have a low modulus, a low stress and a high strain analogous to the stress-strain behavior of non-cross thermoplastic elastomer.

  2. Hybrid estimation technique for predicting butene concentration in polyethylene reactor

    Science.gov (United States)

    Mohd Ali, Jarinah; Hussain, M. A.

    2016-03-01

    A component of artificial intelligence (AI), which is fuzzy logic, is combined with the so-called conventional sliding mode observer (SMO) to establish a hybrid type estimator to predict the butene concentration in the polyethylene production reactor. Butene or co-monomer concentration is another significant parameter in the polymerization process since it will affect the molecular weight distribution of the polymer produced. The hybrid estimator offers straightforward formulation of SMO and its combination with the fuzzy logic rules. The error resulted from the SMO estimation will be manipulated using the fuzzy rules to enhance the performance, thus improved on the convergence rate. This hybrid estimation is able to estimate the butene concentration satisfactorily despite the present of noise in the process.

  3. IONIC LIQUID-CATALYZED ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    Science.gov (United States)

    A detailed study of the alkylation of isobutane with 2-butene in ionic liquid media has been conducted using 1-alkyl-3-methylimidazolium halides?aluminum chloride encompassing various alkyl groups (butyl-, hexyl-, and octyl-) and halides (Cl, Br, and I) on its cations and anions,...

  4. Influence of gamma radiation reaction on the hydroesterification of butenes catalyzed by metal carbonyls

    International Nuclear Information System (INIS)

    In the hydro carboxylation reaction, which first has been studied by Reppe, olefine and acetylene compounds are processed with carbon monoxide and water at high pressures and high temperatures in the presence of metal carbonyls. This reaction can be enhanced considerably by application of ionizing radiation. Lower pressures and in particular lower temperatures can be used if gamma irradiation is performed during carboxylation. For the experiments a mixture of buten-1 and buten-2 as well as pure buten-1 and pure buten-2 has been used to study the behaviour of these olefines with respect to the isomerization of the reaction products and to the olefines not transformed in the reaction process. Replacing water, methanol has been used as a reaction component, thus obtaining directly the respective carbonyl acid esters, which can be analysed quantitatively and qualitatively with respect to their isomeric composition by gaschromatography. (orig./HK)

  5. Coke precursor as an intermediate during the alkylation of isobutane/butene over a solid superacid

    Institute of Scientific and Technical Information of China (English)

    XIE; Wenhua; FU; Qiang

    2004-01-01

    Alkylation of isobutane/butene was conducted on a Brφnsted-Lewis conjugated solid superacid. It is found that some hydrocarbons accumulated on the catalyst surface. These hydrocarbons, as called coke precursor, played an intermediate role at the initial stage of the alkylation before they lead the catalyst to lose its activity. The presence of the intermediate is beneficial to the alkylation between isobutane and butene, while increase the TMP content and TMP/DMH ratio in the products.

  6. Unit for Production of MTBE and Butene-1 from Refinery C4 Successfully Put on Stream at Guangzhou Petrochemical Complex

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ The unit for manufacture of MTBE with co-production of butene-1 was successfully put on stream at Guangzhou Pet-rochemical Complex (GPC). It is told that this is the first domestic unit that utilizes the refinery C4 fraction to make MTBE and butene-1.

  7. Continuous gas-phase hydroformylation of 1-butene using supported ionic liquid phase (SILP) catalysts

    DEFF Research Database (Denmark)

    Haumann, Marco; Dentler, Katharina; Joni, Joni;

    2007-01-01

    another excellent hint for truly homogeneous catalysis in the SILP system. Compared to former studies using propene, the SILP system showed significantly higher activity and selectivity with 1-butene as feedstock. These findings could be elucidated by solubility measurements using a magnetic microbalance.......The concept of supported ionic liquid phase (SILP) catalysis has been extended to 1-butene hydroformylation. A rhodium-sulfoxantphos complex was dissolved in [BMIM][n-C8H17OSO3] and this solution was highly dispersed on silica. Continuous gas-phase experiments in a fixed-bed reactor revealed...

  8. Production of propylene from 1-butene on highly active "bi-functional single active site" catalyst: Tungsten carbene-hydride supported on alumina

    KAUST Repository

    Mazoyer, Etienne

    2011-12-02

    1-Butene is transformed in a continuous flow reactor over tungsten hydrides precursor W-H/Al2O3, 1, giving a promising yield into propylene at 150 °C and different pressures. Tungsten carbene-hydride single active site operates as a "bi-functional catalyst" through 1-butene isomerization on W-hydride and 1-butene/2-butenes cross-metathesis on W-carbene. This active moiety is generated in situ at the initiation steps by insertion of 1-butene on tungsten hydrides precursor W-H/Al2O3, 1 followed by α-H and β-H abstraction. © 2011 American Chemical Society.

  9. On the Absorption of Isobutene and trans-2-Butene in Sulfuric Acid Solutions

    NARCIS (Netherlands)

    Brilman, D.W.F.; Swaaij, W.P.M. van; Versteeg, G.F.

    1997-01-01

    In reactions in which alkenes react in the presence of homogeneous Brønstedt acid catalysts, the protonation step is rate determining. Existing reaction rate correlations for protonation of butenes in sulfuric acid solutions are not consistent and limited to sulfuric acid concentrations below 80 wt

  10. Diffusion Coefficient and Solubility of Isobutene and trans-2-Butene in Aqueous Sulfuric Acid Solutions

    NARCIS (Netherlands)

    Brilman, Derk W.F.; Swaaij, Wim P.M. van; Versteeg, Geert F.

    2001-01-01

    The diffusion coefficient and the physical solubility of isobutene and trans-2-butene in aqueous sulfuric acid solutions cannot be determined experimentally due to the occurrence of fast chemical reactions. In the present contribution these physicochemical parameters are estimated. For the solubilit

  11. Shear effects on crystallization behaviors and structure transitions of isotactic poly-1-butene

    DEFF Research Database (Denmark)

    Li, Jingqing; Guan, Peipei; Zhang, Yao;

    2014-01-01

    Different melt pre-shear conditions were applied to isotactic poly-1-butene (iP-1-B) and the effect on the crystallization behaviors and the crystalline structure transitions of iP-1-B were investigated. The polarized optical microscope observations during isothermal crystallization process revea...

  12. IONIC LIQUIDS AS A CLEAN CATALYST FOR THE ALKYLATION OF ISOBUTANE WITH 2-BUTENE

    Science.gov (United States)

    Ionic liquids as a clean catalyst for the alkylation of isobutane with 2-buteneKyesang Yoo, a Vasudevan V. Namboodiri,b Panagiotis G. Smirniotis,*a and Rajender S. Varma*b a Department of Chemical Engineering, University of Cincinnati, Cincinnati, OH 45221-0171, USA. ...

  13. Cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene and 1-chloro-3-buten-2-one, two alternative metabolites of 1,3-butadiene

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Xin-Jie; Zeng, Fang-Mao; An, Jing; Yu, Ying-Xin [Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Zhang, Xin-Yu, E-mail: xyzhang999@shu.edu.cn [Institute of Environmental Pollution and Health, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 200444 (China); Elfarra, Adnan A., E-mail: elfarra@svm.vetmed.wisc.edu [Department of Comparative Biosciences, University of Wisconsin-Madison, Madison, WI 53706 (United States); Molecular and Environmental Toxicology Center, University of Wisconsin-Madison, Madison, WI 53706 (United States)

    2013-08-15

    The cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene (CHB), a known in vitro metabolite of the human carcinogen 1,3-butadiene, have not previously been investigated. Because CHB can be bioactivated by alcohol dehydrogenases to yield 1-chloro-3-buten-2-one (CBO), a bifunctional alkylating agent that caused globin-chain cross-links in erythrocytes, in the present study we investigated the cytotoxic and genotoxic potential of CHB and CBO in human normal hepatocyte L02 cells using the MTT assay, the relative cloning efficiency assay and the comet assay. We also investigated the mutagenic potential of these compounds with the Ames test using Salmonella strains TA1535 and TA1537. The results provide clear evidence for CHB and CBO being both cytotoxic and genotoxic with CBO being approximately 100-fold more potent than CHB. Interestingly, CHB generated both single-strand breaks and alkali-labile sites on DNA, whereas CBO produced only alkali-labile sites. CHB did not directly result in DNA breaks, whereas CBO was capable of directly generating breaks on DNA. Interestingly, both compounds did not induce DNA cross-links as examined by the comet assay. The Ames test results showed that CHB induced point mutation but not frameshift mutation, whereas the toxic effects of CBO made it difficult to reliably assess the mutagenic potential of CBO in the two strains. Collectively, the results suggest that CHB and CBO may play a role in the mutagenicity and carcinogenicity of 1,3-butadiene. - Highlights: • 1-Chloro-2-hydroxy-3-butene (CHB) is cytotoxic and genotoxic in human liver cells. • The CHB metabolite, 1-chloro-3-buten-2-one (CBO) is ∼ 100-fold more toxic than CHB. • CHB and CBO cause DNA alkali-labile sites, but only CBO directly causes DNA breaks. • CHB is mutagenic in the Ames test, but CBO is too toxic in the assay. • The results suggest a role for CHB in 1,3-butadiene genotoxicity and mutagenicity.

  14. Cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene and 1-chloro-3-buten-2-one, two alternative metabolites of 1,3-butadiene

    International Nuclear Information System (INIS)

    The cytotoxicity, genotoxicity, and mutagenicity of 1-chloro-2-hydroxy-3-butene (CHB), a known in vitro metabolite of the human carcinogen 1,3-butadiene, have not previously been investigated. Because CHB can be bioactivated by alcohol dehydrogenases to yield 1-chloro-3-buten-2-one (CBO), a bifunctional alkylating agent that caused globin-chain cross-links in erythrocytes, in the present study we investigated the cytotoxic and genotoxic potential of CHB and CBO in human normal hepatocyte L02 cells using the MTT assay, the relative cloning efficiency assay and the comet assay. We also investigated the mutagenic potential of these compounds with the Ames test using Salmonella strains TA1535 and TA1537. The results provide clear evidence for CHB and CBO being both cytotoxic and genotoxic with CBO being approximately 100-fold more potent than CHB. Interestingly, CHB generated both single-strand breaks and alkali-labile sites on DNA, whereas CBO produced only alkali-labile sites. CHB did not directly result in DNA breaks, whereas CBO was capable of directly generating breaks on DNA. Interestingly, both compounds did not induce DNA cross-links as examined by the comet assay. The Ames test results showed that CHB induced point mutation but not frameshift mutation, whereas the toxic effects of CBO made it difficult to reliably assess the mutagenic potential of CBO in the two strains. Collectively, the results suggest that CHB and CBO may play a role in the mutagenicity and carcinogenicity of 1,3-butadiene. - Highlights: • 1-Chloro-2-hydroxy-3-butene (CHB) is cytotoxic and genotoxic in human liver cells. • The CHB metabolite, 1-chloro-3-buten-2-one (CBO) is ∼ 100-fold more toxic than CHB. • CHB and CBO cause DNA alkali-labile sites, but only CBO directly causes DNA breaks. • CHB is mutagenic in the Ames test, but CBO is too toxic in the assay. • The results suggest a role for CHB in 1,3-butadiene genotoxicity and mutagenicity

  15. Modeling of Isobutane/Butene Alkylation Using Solid Acid Catalysts in a Fixed Bed Reactor

    Institute of Scientific and Technical Information of China (English)

    Liu Zheng; Tang Xiaojin; Hu Lifeng; Hou Shuandi

    2016-01-01

    A dynamic mass transfer model of isobutane/butene alkylation over solid acid catalysts in a ifxed bed reactor was established. In the model, a modiifed equation for the relationship between point activity and effective diffusion coefifcient was proposed. It is found that the simulation results ift the experimental data well and the breakthrough time of the bed layer is predicted accurately. By modeling the alkylation process, the time-space distribution of butene and point activity proifles of catalysts can be obtained. Furthermore, the reasons for the deactivation of solid acid catalysts were investigated. It indicates that the main reason for the deactivation of catalysts is the site coverage near the inlet of the reactor, while it is ascribed to the steric effect in the region far away from the inlet.

  16. Oxidative Dehydrogenation of Butane to Butadiene and Butene Using a Novel Inert Membrane Reactor

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The oxidative dehydrogenation of butane to butadiene and butene was studied using a conventional fixed-bed ractor (FBR), inert membrane reactor (IMR) and mixed inert membrane reactor (MIMR). When IMR and MIMR were employed, a ceramic membrane modified by partially coating with glaze was used to distribute oxygen to a fixed-bed of 24-V-Mg-O catalyst. The oxygen partial pressure in the catalyst bed could be decreased. The effect of feeding modes and operation conditions were investigated. The selectivity of C4 dehydrogenation products (butene and butadiene) was found to be higher in IMR than in FBR. The feeding mode with 20% of air mixing with butane in MIMR was found to be more efficient than the feeding mode with all air permeating through ceramic membrane. The MIMR gave the most smooth temperature profile along the bed.

  17. Conversion of n-Butane to iso-Butene on Gallium/HZSM-5 Catalysts

    Directory of Open Access Journals (Sweden)

    S.M. Gheno

    2002-07-01

    Full Text Available The conversion of n-butane to iso-butene on gallium/HZSM-5 catalysts at 350ºC and WHSV=2.5h8-1 was studied. The catalysts were prepared by ion exchange from a Ga(NO32 solution and further submitted to calcination in air at 530ºC. TEM analysis with an EDAX detector and TPR-H2 data showed that after calcination the Ga species were present mainly as Ga2O3, which are reduced to Ga2O at temperatures near 610ºC. The specific acid activity (SAA of the catalysts increased with the increase in aluminum content in the zeolite, and for a fixed Si/Al ratio, the SAA increased with Ga content. Values for specific hydro/dehydrogenation activity (SH/DHA were significantly higher than those for SAA, indicating that the catalytic process is controlled by the kinetics on acid sites. Moreover, the production of iso-butene with a selectivity higher than 25% was a evidence that in gallium/HZSM-5-based catalysts the rate of the hydrogenation reaction is lower than that of the dehydrogenation reaction; this behavior confirmed the dehydrogenation nature of gallium species, thereby showing great promise for iso-butene production.

  18. Alkylation of Isobutane and Butene on BrΦnsted-Lewis Conjugated Solid Superacids

    Institute of Scientific and Technical Information of China (English)

    Xie Wenhua; Fu Qiang; He Yigong; Min Enze

    2004-01-01

    A BrΦnsted-Lewis (B-L) conjugated solid superacid HPW-SbF5/SiO2 was synthesized by a two-step method. This B-L acid shows high acid strength, high activity, good selectivity and moderate stability in alkylation of isobutane/butene due to strong interaction between the BrΦnsted acid and the Lewis acid, as confirmed by the results of IR, NMR and XPS. Under a mild reaction condition (30℃, 15-35x105 Pa), the conversion of butene was maintained at 100% for 1 10 hours on stream and the main products were C8 and TMP. The results of alkylation conducted under various operating conditions indicated that the activity was improved by increasing the loading content of HPW and SbF5. The selectivity of TMP in the products was enhanced when the isobutane/butene ratio in the feedstock was increased. The existence of some intermediates was also reported.

  19. Electrochemical Behavior and Semiempirical Approach to the Electroadsorption of 3-Buten-2-one and 2-Butanone on Platinum.

    Science.gov (United States)

    Zinola; Castro Luna AM

    1999-11-15

    The electroadsorption of 3-buten-2-one was studied on polycrystalline and faceted Pt electrodes in aqueous 0.5 M H(2)SO(4) between 20 and 70 degrees C using voltammetric and transient techniques. The largest values of anodic charge densities in stripping experiments were observed at the potential of zero charge of the Pt/acid interface (ca. 0.20 V), that is, 550, 680, and 720 µC cm(-2), on polycrystalline and (111)- and (100)-faceted electrodes, respectively. The anodic and cathodic strippings of 3-buten-2-one showed the formation of at least two residues with different electrochemical behavior. For comparison cyclic voltammetries and current transients of 2-butanone on Pt were also studied. To get a deeper insight into the adsorption configurations of 3-buten-2-one and 2-butanone, the extended Hückel molecular orbital methodology was used to predict adsorption geometries and binding energies on simulated Pt(100) and Pt(111) single-crystal surfaces. At equilibrium potentials, two types of adsorbed species were recognized, a planar 3-buten-2-one formed by the interaction of carbonyl and alkene groups and adsorbates coming from the single interaction of the >C&dbond;O moiety for both 3-buten-2-one and 2-butanone. At simulated positive potentials, 3-buten-2-one adsorption occurred on Pt(111) and Pt(100) clusters through the pi-orbitals of the >C&dbond;C< moiety, whereas at negative potentials 3-buten-2-one was adsorbed via µ-bridging or di-varsigma configuration(s). Copyright 1999 Academic Press. PMID:10534385

  20. Acidic and basic properties of zeolite-containing cracking catalyst in the process of butene-1 isomerization

    Science.gov (United States)

    Mursalova, L. A.; Guseinova, E. A.; Adzhamov, K. Yu.

    2016-08-01

    The process of butene-1 isomerization in the presence of two groups of samples of zeolite-containing catalyst (ZCC) that earlier participated in the traditional and oxidative catalytic cracking of vacuum gasoil is investigated. It is established that the nature of the reaction mixture and conditions of the cracking process are key factors in forming the acidic and basic properties of the catalyst. It is shown that the highest activity in the butene-1 isomerization into cis-/ trans-butene-2 is demonstrated by ZCC samples that participated in the oxidative catalytic cracking (oxycracking). It is suggested that the enhanced catalytic activity of this group of ZCC samples was related to the availability of acid-base centers in the form of radical-like oxygen along with protic- and aprotic-type acidic centers in the structure of the oxidative compaction products.

  1. Synthesis and characterization of star-comb polybutadiene and poly(ethylene-co-butene)

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    A novel star-comb polybutadiene(SC-PB) was synthesized with n-butyllithium(n-BuLi) as initiator,epoxidized star liquid polybutadiene(ESPB) as coupling agent,cyclohexane as solvent by living anionic polymerization and grafting-onto technology. The SC-PB was subsequently hydrogenated by homogeneous catalysis(catalytic hydrogenation using nickel naphthenate/ triisobutyl aluminum),to transform the SC-PB into the corresponding star-comb poly(ethylene-co-butene)(SC-PEB).The SC-PB was characterized by SEC-TALLS...

  2. Alkyl-halogenide promoted ionic liquid catalysis of isobutane/butene-alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Schilder, L.; Korth, W.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2011-07-01

    The effect of two different types of promoters on the performance of Lewis-acidic chloroaluminate ionic liquid catalysts was studied for liquid liquid biphasic isobutane/2-butene alkylation. In particular, the activity and selectivity of such catalytic systems was investigated. Experimental results obtained from a batch reactor show, that tert-butyl halides increase the reaction rate significantly and shift the C8-selectivity towards the desired high-octane trimethylpentanes (TMPs). But, secondary reactions like oligomerization and cracking are not affected by the use of these promoters. (orig.)

  3. Low Temperature Wafer Level Hermetic Package with Benzo-cyclo-butene Material

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The wafer level hermetic package method was studied experimentally in low temperature for optoelectronic devices with benzo-cyclo-butene(BCB) material. The results show that the bonding temperature is below 250℃, the helium hermetic capability of both silicon-BCB-silicon and silicon-BCB-glass package are better than 6×10-4Pa·cm3/s. The shear strength is enough for package. The hermeticity is still good after the 15 cycles' thermal shock test. The relationship between the leakage rate and the distance from the hole to the device border were also discussed with a seepage model.

  4. A new transitory product in the ozonolysis of trans-2-butene at atmospheric pressure

    Science.gov (United States)

    Horie, O.; Moortgat, G. K.

    1989-03-01

    A previously unidentified transitory species, tentatively assigned as hydroxyethyl formate, CH 3CH (OH)-O-CHO, was formed as a major product in the ozonolysis of trans-2-butene at atmospheric pressure. A continuous stirred-tank reactor was used to analyze reaction products via molecular-beam sampling and matrix isolation FTIR spectroscopy. CH 3CHO, HCHO, CO 2, CO, CH 3OH, CH 4 and H 2O were the main, HCOOH and CH 2CO the minor, products. CH 3COOH and propene ozonide were detected as trace components.

  5. Catalytic cracking of 1-butene to propylene by Ag modified HZSM-5

    Institute of Scientific and Technical Information of China (English)

    Rongrong Zhang; Zhengbao Wang

    2015-01-01

    Silver modified HZSM-5 (AgHZ) zeolite catalysts were prepared by ion exchange method and their catalytic properties in the 1-butene cracking reaction were measured. The catalysts were characterized by infrared spec-troscopy with pyridine adsorption (Py-IR), N2 adsorption and X-ray diffraction (XRD). The effects of Ag loading and steaming treatment on catalytic performances were studied. It is found that the activity of HZSM-5 (HZ) cat-alyst significantly decreases with the steaming time, whereas AgHZ catalysts show stable activity in the steaming time of 24–48 h and their activities increase with the Ag loading. When the steaming time is 24–48 h, the yield of propylene over HZ catalyst significantly decreases, whereas it is stable over AgHZ catalysts. The AgHZ catalysts with Ag loadings of 0.28%–0.43%(by mass) show similar propylene yields (~30%), which are higher than that over the AgHZ catalyst with a Ag loading of 0.55%(by mass). These results indicate that the steam-treated AgHZ catalysts with optimum Ag loadings have higher yield of propylene and are more stable than the steam-treated HZ catalyst. The regeneration stability measurement in butene cracking also shows that the AgHZ catalyst steam-treated under a suitable condition has better stability than the HZ catalyst.

  6. Organosulfates as Tracers for Secondary Organic Aerosol (SOA) Formation from 2-Methyl-3-Buten-2 ol (MBO) in the Atmosphere

    Science.gov (United States)

    2-Methyl-3-buten-2-ol (MBO) is an important biogenic volatile organic compound (BVOC) emitted by pine trees and a potential precursor of atmospheric secondary organic aerosol (SOA) in forested regions. In the present study, hydroxyl radical (OH)-initiated oxidation of MBO was exa...

  7. Oxidative Dehydrogenation of n-Butenes to 1,3-Butadiene over Bismuth Molybdate and Ferrite Catalysts: A Review

    KAUST Repository

    Hong, Eunpyo

    2015-11-02

    1,3-Butadiene, an important raw material for a variety of chemical products, can be produced via the oxidative dehydrogenation (ODH) of n-butenes over multicomponent oxide catalysts based on bismuth molybdates and ferrites. In this review, the basic concept, reaction mechanism, and catalysts typically used in an ODH reaction are discussed. © 2015, Springer Science+Business Media New York.

  8. Metallacyclobutane substitution and its effect on alkene metathesis for propylene production over W-H/Al2O3: Case of isobutene/2-butene cross-metathesis

    KAUST Repository

    Szeto, Kaï Chung

    2013-09-06

    Cross metathesis between 2-butenes and isobutene yielding the valuable products propylene and 2-methyl-2-butene has been investigated at low pressure and temperature using WH3/Al2O3, a highly active and selective catalyst. Two parallel catalytic cycles for this reaction have been proposed where the cycle involving the less sterically hindered tungstacyclobutane intermediates is most likely favored. Moreover, it has been found that the arrangement of substituents on the least thermodynamically favored tungstacyclobutane governs the conversion rate of the cross metathesis reaction for propylene production from butenes and/or ethylene. © 2013 American Chemical Society.

  9. Antibacterial properties and mode of action of new triaryl butene citrate compounds.

    Science.gov (United States)

    El Arbi, Mehdi; Théolier, Jérémie; Pigeon, Pascal; Jellali, Karim; Trigui, Fatma; Top, Siden; Aifa, Sami; Fliss, Ismail; Jaouen, Gérard; Hammami, Riadh

    2014-04-01

    The aim of this study was to evaluate the antibacterial activity of newly synthesized triaryl butene analogues of tamoxifen. Several compounds were synthesized and converted to citrate salts to ensure greater solubility. Four compounds showed significant antibacterial activity at micromolar concentrations against Gram-positive and Gram-negative foodborne pathogens including Listeria monocytogenes, Listeria ivanovii, Enterococcus faecalis, Staphylococcus aureus and Escherichia coli. Two compounds at 50 μM, caused only 7.8 and 11% hemolysis. One of these as well as the remaining two caused high K(+) and Na(+) efflux from bacterial cells. Ultrastructural alterations were also visible using transmission electron microscopy, which revealed severe damage of the inner or outer membrane of E. coli. L. ivanovii showed swelling, corrugations and similar damage indicating a loss of cell-wall integrity. Organometallic compounds may offer interesting opportunities for the design of novel classes of antimicrobial compounds. PMID:24602786

  10. Influence of mass transport towards deactivation in tert-butyl-source driven isobutane/2-butene alkylation

    Energy Technology Data Exchange (ETDEWEB)

    Aschauer, S.J.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2011-07-01

    The deactivation of i-butane/trans-2-butene alkylation using tert-butyl-halide promoted ionic liquid catalysts is studied.Here, the mass transport was modified by varying the feed rate and the type of promoter addition. The experimental data show that the deactivation increases with increasing feed rate. Moreover, a biliquid foam is formed when feed rates above 1 g/min are adjusted. As the results indicate a strong influence of the biliquid foam and its formation on deactivation, both aspects are also discussed.When the promoter is added to the feed mixture an increase of conversion with time on stream is observed. A deactivation in continuous promoter addition mode could not be noted in the investigated time-on-stream range. (orig.)

  11. Radiation-induced oxidation of polyethylene, ethylene-butene copolymer, and ethylene-propylene copolymer

    International Nuclear Information System (INIS)

    Oxygen consumption and yield of oxidation products during ν-irradiation were studied on five types of polyethylene (PE), ethylene-butene copolymer (EB), and ethylene-propylene copolymer (EPR) using gas chromatography, mass spectrography, and high-resolution NMR. Samples were irradiated in oxygen under pressure from 0 to 500 torr by 60Co ν-rays up to 20 Mrad at 22-250C. In enough oxygen, oxygen consumption and yield of oxidation products are independent of oxygen pressure for low-density PE, EB, and EPR. The G values of oxygen consumption were 14-18.4 for PE, 11.6 for EB at 1 x 106 rad/h, and 8.3 for EPR at 2 x 105 rad/h. The oxidation products determined were carboxylic acid (-CH2-CO-OH), H2O, CO2, and CO. The oxygen consumption and oxidation products for PE were found to increase with increasing crystallinity

  12. Catalytic production of biofuels (butene oligomers) and biochemicals (tetrahydrofurfuryl alcohol) from corn stover.

    Science.gov (United States)

    Byun, Jaewon; Han, Jeehoon

    2016-07-01

    A strategy is presented that produces liquid hydrocarbon fuels (butene oligomers (BO)) from cellulose (C6) fraction and commodity chemicals (tetrahydrofurfuryl alcohol (THFA)) from hemicellulose (C5) of corn stover based on catalytic conversion technologies using 2-sec-butylphenol (SBP) solvents. This strategy integrates the conversion subsystems based on experimental studies and separation subsystems for recovery of biomass derivatives and SBP solvents. Moreover, a heat exchanger network is designed to reduce total heating requirements to the lowest level, which is satisfied from combustion of biomass residues (lignin and humins). Based on the strategy, this work offers two possible process designs (design A: generating electricity internally vs. design B: purchasing electricity externally), and performs an economic feasibility study for both the designs based on a comparison of the minimum selling price (MSP) of THFA. This strategy with the design B leads to a better MSP of $1.93 per kg THFA. PMID:27030955

  13. Experimental and Kinetic Modeling Study of 2-Methyl-2-Butene: Allylic Hydrocarbon Kinetics.

    Science.gov (United States)

    Westbrook, Charles K; Pitz, William J; Mehl, Marco; Glaude, Pierre-Alexandre; Herbinet, Olivier; Bax, Sarah; Battin-Leclerc, Frederique; Mathieu, Olivier; Petersen, Eric L; Bugler, John; Curran, Henry J

    2015-07-16

    Two experimental studies have been carried out on the oxidation of 2-methyl-2-butene, one measuring ignition delay times behind reflected shock waves in a stainless steel shock tube, and the other measuring fuel, intermediate, and product species mole fractions in a jet-stirred reactor (JSR). The shock tube ignition experiments were carried out at three different pressures, approximately 1.7, 11.2, and 31 atm, and at each pressure, fuel-lean (ϕ = 0.5), stoichiometric (ϕ = 1.0), and fuel-rich (ϕ = 2.0) mixtures were examined, with each fuel/oxygen mixture diluted in 99% Ar, for initial postshock temperatures between 1330 and 1730 K. The JSR experiments were performed at nearly atmospheric pressure (800 Torr), with stoichiometric fuel/oxygen mixtures with 0.01 mole fraction of 2M2B fuel, a residence time in the reactor of 1.5 s, and mole fractions of 36 different chemical species were measured over a temperature range from 600 to 1150 K. These JSR experiments represent the first such study reporting detailed species measurements for an unsaturated, branched hydrocarbon fuel larger than iso-butene. A detailed chemical kinetic reaction mechanism was developed to study the important reaction pathways in these experiments, with particular attention on the role played by allylic C-H bonds and allylic pentenyl radicals. The results show that, at high temperatures, this olefinic fuel reacts rapidly, similar to related alkane fuels, but the pronounced thermal stability of the allylic pentenyl species inhibits low temperature reactivity, so 2M2B does not produce "cool flames" or negative temperature coefficient behavior. The connections between olefin hydrocarbon fuels, resulting allylic fuel radicals, the resulting lack of low-temperature reactivity, and the gasoline engine concept of octane sensitivity are discussed. PMID:25822578

  14. DEVELOPMENT OF OPTIMAL PARAMETERS FOR NEW DERIVANTS DETERMINATION OF 4-(GETARYL-2-HYDROXY-4-OXO-2-BUTENIC ACIDS IN THIN LAYER OF SORBENT

    Directory of Open Access Journals (Sweden)

    F. V. Sobin

    2014-01-01

    Full Text Available We have carried out a selection of optimal conditions for chromatographic control of four classes of potentially biologically active derivants of 4-(getaril-2-hydroxy-4-oxo-2-butenic acids.

  15. Henry's constants and infinite dilution activity coefficients of propane, propene, butane, isobutane, 1-butene, isobutene, trans-2-butene, and 1,3-butadiene in isobutanol and tert-butanol

    International Nuclear Information System (INIS)

    The Henry's constants and the infinite dilution activity coefficients of propane, propene, butane, isobutane, 1-butene, isobutene, trans-2-butene and 1,3-butadiene in isobutanol at T = (250 to 330) K and tert-butanol at T (300 to 330) K are measured by a gas stripping method. The rigorous formula for evaluating the Henry's constants from the gas stripping measurements is used for data reduction of these highly volatile mixtures. The accuracy of the measurements is about 2% for Henry's constants and 3% for the estimated infinite dilution activity coefficients. In the evaluations for the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and the Pointing correction is not negligible, especially at higher temperatures, and the estimation uncertainty in the infinite dilution activity coefficients includes 1% for nonideality

  16. Henry's law constants and infinite dilution activity coefficients of propane, propene, butane, isobutane, 1-butene, isobutene, trans-2-butene, and 1,3-butadiene in 1-pentanol, 2-pentanol, and 3-pentanol

    International Nuclear Information System (INIS)

    Henry's law constants and infinite dilution activity coefficients of propane, propene, butane, isobutane, 1-butene, isobutene, trans-2-butene, and 1,3-butadiene in 1-pentanol, 2-pentanol in the temperature range of (250 to 330) K and 3-pentanol in the temperature range of (260 to 330) K were measured by a gas stripping method. A rigorous formula for evaluating the Henry's law constants from the gas stripping measurements was used for the data reduction of these highly volatile mixtures. The uncertainty is about 2% for the Henry's law constants and 3% for the estimated infinite dilution activity coefficients. In the evaluation of the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and Pointing correction factor cannot be neglected, especially at higher temperatures. The estimated uncertainty of the infinite dilution activity coefficients includes 1% for nonideality

  17. Sulfur dioxide oxidation induced mechanistic branching and particle formation during the ozonolysis of β-pinene and 2-butene.

    Science.gov (United States)

    Carlsson, Philip T M; Keunecke, Claudia; Krüger, Bastian C; Maaß, Mona-C; Zeuch, Thomas

    2012-12-01

    Recent studies have suggested that the reaction of stabilised Criegee Intermediates (CIs) with sulfur dioxide (SO(2)), leading to the formation of a carbonyl compound and sulfur trioxide, is a relevant atmospheric source of sulfuric acid. Here, the significance of this pathway has been examined by studying the formation of gas phase products and aerosol during the ozonolysis of β-pinene and 2-butene in the presence of SO(2) in the pressure range of 10 to 1000 mbar. For β-pinene at atmospheric pressure, the addition of SO(2) suppresses the formation of the secondary ozonide and leads to highly increased nopinone yields. A complete consumption of SO(2) is observed at initial SO(2) concentrations below the yield of stabilised CIs. In experiments using 2-butene a significant consumption of SO(2) and additional formation of acetaldehyde are observed at 1 bar. A consistent kinetic simulation of the experimental findings is possible when a fast CI + SO(2) reaction rate in the range of recent direct measurements [Welz et al., Science, 2012, 335, 204] is used. For 2-butene the addition of SO(2) drastically increases the observed aerosol yields at higher pressures. Below 60 mbar the SO(2) oxidation induced particle formation becomes inefficient pointing to the critical role of collisional stabilisation for sulfuric acid controlled nucleation at low pressures. PMID:23090096

  18. DFT Studies on the Isomerization of Butene Double Bond Catalyzed by 1-Butyl-3-methyl-imidazolium in Ionic Liquid

    Institute of Scientific and Technical Information of China (English)

    LI Ying-Xia; PU Min; CHEN Biao-Hua; LI Hui-Ying; LIU Kun-Hui; WANG Wen-Xing

    2005-01-01

    The geometries of reactant, product and transition state of the title reaction have been optimized by using density functional theory (DFT) at the B3LYP/6-31G(d,p) and B3LYP/6- 311++G(d,p) levels.The variations of the bond parameters in the course of reaction were analyzed.The zero point energy corrections were performed by vibrational analysis.The equilibrium states and the transition state were verified according to the number of virtue frequency of geometry.The intrinsic reaction coordinates (IRC) were calculated from the transition state.The calculated results show that the double bond rearrangement of butene catalyzed by 1-butyl-3-methyl-imidazolium cation is a one-step reaction.The forward energy barrier of isomerization from 1-butene to 2- butene is about 193 kJmol-1 and the reverse energy barrier about 209 kJmol-1 at the B3LYP/6- 31G(d,p) level, which means that the reaction is easy to proceed at or above room temperature.

  19. Investigation of the thermal and photochemical reactions of ozone with 2,3-dimethyl-2-butene.

    Science.gov (United States)

    Coleman, Bridgett E; Ault, Bruce S

    2010-12-01

    The matrix isolation technique, combined with infrared spectroscopy and twin jet codeposition, has been used to characterize intermediates formed during the ozonolysis of 2,3-dimethyl-2-butene (DMB). Absorptions of early intermediates in the twin jet experiments grew up to 200% upon annealing to 35 K. A number of these absorptions have been assigned to the elusive Criegee intermediate (CI) and secondary ozonide (SOZ) of DMB, transient species not previously observed for this system. Also observed was the primary ozonide (POZ), in agreement with earlier studies. The wavelength dependence of the photodestruction of these product bands was explored with irradiation from λ ≥ 220 to ≥580 nm. Merged jet (flow reactor) experiments generated "late" stable oxidation products of DMB. A recently developed concentric jet method was also utilized to increase yields and monitor the concentration of intermediates and products formed at different times by varying the length of mixing distance (d = 0 to -11 cm) before reaching the cold cell for spectroscopic detection. Identification of intermediates formed during the ozonolysis of DMB was further supported by (18)O and scrambled (16,18)O isotopic labeling experiments as well as theoretical density functional calculations at the B3LYP/6-311++G(d,2p) level. PMID:21077641

  20. Temperature-dependent absorption cross-section measurements of 1-butene (1-C4H8) in VUV and IR

    KAUST Repository

    Es-sebbar, Et-touhami

    2013-01-01

    Vacuum ultraviolet (VUV) and infrared (IR) absorption cross-section measurements of 1-butene (1-C4H8; CH2=CHCH2CH3; Butylene) are reported over the temperature range of 296-529K. The VUV measurements are performed between 115 and 205nm using synchrotron radiation as a tunable VUV light source. Fourier Transform Infrared (FTIR) spectroscopy is employed to measure absorption cross-section and band strengths in the IR region between 1.54 and 25μm (~6500-400cm-1). The measured room-temperature VUV and IR absorption cross-sections are compared with available literature data and are found to be in good agreement. The oscillator strength for the electronic transition (A1A\\'→X1A\\') around 150-205nm is determined to be 0.32±0.01.The gas temperature has a strong effect on both VUV and IR spectra. Measurements made in the VUV region show that the peak value of the band cross-section decreases and the background continuum increases with increasing gas temperature. This behavior is due to a change in the rotational and vibrational population distribution of 1-butene molecule. Similar changes in rotational population are observed in the IR spectra. Moreover, variation of the IR spectra with temperature is used to measure the enthalpy difference between syn and skew conformations of 1-butene and is found to be 0.24±0.03. kcal/mol, which is in excellent agreement with values reported in the literature. The measurements reported in this work will provide the much-needed spectroscopic information for the development of high-temperature quantitative diagnostics in combustion applications and validation of atmospheric chemistry models of extra-solar planets. © 2012 Elsevier Ltd.

  1. Polymer coatings on plane and spherical surfaces obtained by plasma polymerization from trans-2-butene and hydrogen mixture

    International Nuclear Information System (INIS)

    This study of a low frequency plasma polymerization process was undertaken to be used in manufacturing of targets used in laser-matter interaction experiments. In this system, whether the sample is placed in the discharge or outside of the discharge, hydrocarbon coatings from a gaseous mixture of hydrogen and trans-2-butene are obtain. This study consists of two parts. We first dealt with the understanding of plasma polymerization mechanisms in the reactor which resulted in a better process optimization. The study of gas flow in the reactor allowed us to determine the species repartition in the vessel. With experiments performed on the electrical behavior in the reactor we were able to define the discharge type. Then, species present in the plasma were analysed by emission spectroscopy and mass spectrometry and then reaction mechanisms were proposed. Attention was paid to the role of hydrogen which in fact acted as a reagent like trans-2-butene. We also worked on the process optimization in order to obtain a good working point which produces coatings which are as transparent as possible, contain only carbon and hydrogen (and the least amount of oxygen), have a smooth surface finish (mean square root of roughness < 50 nm) and retain their qualities overtime. After the reactor characterization, the study of the effects of different parameters (inner or post-discharge coatings, pressure, total gas flow, composition of the mixture of trans-2-butene and hydrogen, power, frequency, interelectrode distance) on deposition rate, roughness and chemical composition of coatings led to the finding of optimal deposition conditions. (author)

  2. Sulfur dioxide oxidation induced mechanistic branching and particle formation during the ozonolysis of β-pinene and 2-butene.

    OpenAIRE

    Carlsson, Philip T. M.; Keunecke, Claudia; Krüger, Bastian C.; Maaß, Mona-C.; Zeuch, Thomas

    2012-01-01

    Recent studies have suggested that the reaction of stabilised Criegee Intermediates (CIs) with sulfur dioxide (SO(2)), leading to the formation of a carbonyl compound and sulfur trioxide, is a relevant atmospheric source of sulfuric acid. Here, the significance of this pathway has been examined by studying the formation of gas phase products and aerosol during the ozonolysis of β-pinene and 2-butene in the presence of SO(2) in the pressure range of 10 to 1000 mbar. For β-pinene at atmospheric...

  3. Antifungal activity of 4'-(2,6,6-Trimethyl-2-cyclohexen-1-yl)-3'-butene-2'-ketoxime N-O-alkyl ethers.

    Science.gov (United States)

    Banerjee, Tirthankar; Dureja, Prem

    2010-01-27

    A number of 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'-ketoxime N-O-alkyl ethers were prepared, separated into their E and Z isomers, and characterized on the basis of (1)H NMR and mass spectroscopy. These compounds were tested in vitro for antifungal activity against four important phytopathogenic fungi, namely, Sclerotium rolfsii , Rhizoctonia bataticola , Macrophomina phaseolina , and Sclerotinia sclerotiorum . E isomers of 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'-ketoxime N-O-propyl ether (ED(50) = 32.36 microg mL(-1)) and 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'-ketoxime N-O-(1''-methyl) ethyl ether (ED(50) = 35.50 microg mL(-1)) showed maximum antifungal activity against R. bataticola and S. rolfsii, respectively, whereas 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'(Z)-ketoxime N-O-pentyl ether was found to be active against M. phaseolina (ED(50) = 31.08 microg mL(-1)) and S. sclerotiorum (ED(50) 21.39 microg mL(-1)), respectively. The Z isomer of 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'-ketoxime N-O-pentyl ether, which was found to be most effective, was tested against S. sclerotiorum in a greenhouse at 1 and 5% concentrations. The 5% aqueous emulsion of 4'-(2,6,6-trimethyl-2-cyclohexen-1-yl)-3'-butene-2'(Z)-ketoxime N-O-pentyl ether suppressed disease development in pea by 90-95% as compared with the untreated infested soil in the greenhouse after 21 days of treatment. PMID:20038099

  4. Formation of 1,4-dioxo-2-butene-derived adducts of 2'-deoxyadenosine and 2'-deoxycytidine in oxidized DNA.

    Science.gov (United States)

    Chen, Bingzi; Vu, Choua C; Byrns, Michael C; Dedon, Peter C; Peterson, Lisa A

    2006-08-01

    Oxidation of deoxyribose in DNA produces a variety of electrophilic residues that are capable of reacting with nucleobases to form adducts such as M(1)dG, the pyrimidopurinone adduct of dG. We now report that deoxyribose oxidation in DNA leads to the formation of oxadiazabicyclo(3.3.0)octaimine adducts of dC and dA. We previously demonstrated that these adducts arise in reactions of nucleosides and DNA with trans-1,4-dioxo-2-butene, the beta-elimination product of the 2-phosphoryl-1,4-dioxobutane residue arising from 5'-oxidation of deoxyribose in DNA, and with cis-1,4-dioxo-2-butene, a metabolite of furan. Treatment of DNA with enediyne antibiotics capable of oxidizing the 5'-position of deoxyribose (calicheamicin and neocarzinostatin) led to a concentration-dependent formation of oxadiazabicyclo(3.3.0)octaimine adducts of dC and dA, while the antibiotic bleomycin, which is capable of performing only 4-oxidation of deoxyribose, did not give rise to the adducts. The nonspecific DNA oxidant, gamma-radiation, also produced the adducts that represented approximately 0.1% of the 2-phosphoryl-1,4-dioxobutane residues formed during the irradiation. These results suggest that the oxadiazabicyclo(3.3.0)octaimine adducts of dC and dA could represent endogenous DNA lesions arising from oxidative stresses that also give rise to other DNA adducts. PMID:16918236

  5. Grafting of diethyl maleate and maleic anhydride onto styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS)

    NARCIS (Netherlands)

    Picchioni, F.; Ghetti, S.; Passaglia, E.; Ruggeri, G.

    2000-01-01

    In this paper a study of the bulk functionalization of styrene-b-(ethylene-co-1-butene)-b-styrene triblock copolymer (SEBS) with diethyl maleate (DEM) or maleic anhydride (MAH) and dicumyl peroxide (DCP) as initiator in a Brabender mixer is described. The determination of the functionalization degre

  6. SOA Formation from the Atmospheric Oxidation of 2-Methyl-3-Buten-2-ol and Its Implications for PM2.5

    Science.gov (United States)

    The formation of secondary organic aerosol (SOA) generated by irradiating 2-methyl-3-buten-2-01 (MBO) in the presence and/or absence of NOx H2O2, and/or SO2 was examined. Experiments were conducted. in smog chambers operated either in dyna....

  7. Oxidative Dehydrogenation of n-Butenes over BiFe{sub 0.65}MoP{sub 0.1} Oxide Catalysts Prepared with Various Synthesis Method

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jung-Hyun; Shin, Chae-Ho [Chungbuk National University, Cheongju (Korea, Republic of)

    2015-02-15

    To investigate the effect of the catalyst synthesis method on the oxidative dehydrogenation (ODH) of n-butenes, BiFe{sub 0.65}MoP{sub 0.1} oxide catalysts were prepared with various synthesis methods such as co-precipitation, citric acid method, hydrothermal method, and surfactant templated method. The catalysts were characterized by X-ray Diffraction (XRD), N{sub 2} sorption, and NH{sub 3}/1-butene-temperature programmed desorption (NH{sub 3}/1-butene-TPD) to correlate with catalytic activity in ODH reaction. Among the catalysts studied here, BiFe{sub 0.65}MoP{sub 0.1} oxide catalyst prepared with co-precipitation method marked the highest activity showing 1-butene conversion, 79.5%, butadiene selectivity, 85.1% and yield, 67.7% after reaction for 14 h. From the result of NH{sub 3}-TPD, the catalytic activity is closely related to the acidity of the BiFe{sub 0.65}MoP{sub 0.1}-x oxide catalyst and acidity of the BiFe{sub 0.65}MoP{sub 0.1} oxde catalyst prepared with co-precipitation method was higher than that of other catalysts. In addition, combined with the 1-butene TPD, the higher catalytic activity is closely related to the amount of weakly adsorbed intermediate (<200 .deg. C) and the desorbing temperature of strongly adsorbed intermediates (>200 .deg. C)

  8. 3-Methyl-2-butene-1-thiol: identification, analysis, occurrence and sensory role of an uncommon thiol in wine.

    Science.gov (United States)

    San-Juan, Felipe; Cacho, Juan; Ferreira, Vicente; Escudero, Ana

    2012-09-15

    A highly uncommon odorant, 3-methyl-2-butene-1-thiol was detected by using Gas Chromatography-Olfactometry (GC-O) and unequivocally identified for the first time in wine. A purge and trap sampling technique which provides highly representative extracts for olfactometric analysis was used for the extraction of the volatile fraction of a Spanish red wine made from Prieto Picudo grapes. The identification of the odorant was achieved by multidimensional gas chromatography analysis of the same purge and trap extract. Mass spectrum and retention indices in both polar and non-polar columns allowed knowing unequivocally the identity. To obtain quantitative data a method was validated for the analysis of the compound at ng L(-1) level with acceptable precision. This powerful odorant presented an odor threshold in wine of 0.5-1 ng L(-1) and it has been detected in several Prieto Picudo wines at concentrations slightly above the odor threshold.

  9. Electrical conductivity and equation of state of liquid nitrogen, oxygen, benzene, and 1-butene shocked to 60 GPa

    International Nuclear Information System (INIS)

    Measurements are reported for the electrical conductivity of liquid nitrogen (N2), oxygen (O2) and benzene (C6H6), and Hugoniot equation of state of liquid 1-butene (C4H8) under shock compressed conditions. The conductivity data span 7 x 10-4 to 7 x 101 Ω-1cm-1 over a dynamic pressure range 18.1 to 61.5 GPa and are discussed in terms of amorphous semiconduction models which include such transport phenomena as hopping, percolation, pseudogaps, and metallization. Excellent agreement is found between the equation-of-state measurements, which span a dynamic pressure range 12.3 to 53.8 GPa, and Ree's calculated values which assume a 2-phase mixture consisting of molecular hydrogen and carbon in a dense diamond-like phase. There is a 2-1/2 fold increase in the thermal pressure contribution over a less dense, stoichiometrically equivalent liquid. 90 refs., 48 figs., 8 tabs

  10. Influence of phosphorous addition on Bi3Mo2Fe1 oxide catalysts for the oxidative dehydrogenation of 1-butene

    KAUST Repository

    Park, Jung-Hyun

    2016-01-22

    Bi3Mo2Fe1Px oxide catalysts were prepared by a co-precipitation method and the influence of phosphorous content on the catalytic performance in the oxidative dehydrogenation of 1-butene was investigated. The addition of phosphorous up to 0.4mole ratio to Bi3Mo2Fe1 oxide catalyst led to an increase in the catalytic performance; however, a higher phosphorous content (above P=0.4) led to a decrease of conversion. Of the tested catalysts, Bi3Mo2Fe1P0.4 oxide catalyst exhibited the highest catalytic performance. Characterization results showed that the catalytic performance was related to the quantity of a π-allylic intermediate, facile desorption behavior of adsorbed intermediates and ability for re-oxidation of catalysts. © 2015 Korean Institute of Chemical Engineers, Seoul, Korea

  11. Novel and Chemoselective Dehydrogenation of 3,4-Dihydropyrimidin-2(1H)-ones with 1,4-Bis(triphenylphosphonium)-2-butene Peroxodisulfate

    Energy Technology Data Exchange (ETDEWEB)

    Gorjizadeh, Maryam [Islamic Azad Univ., Tehran (Iran, Islamic Republic of)

    2013-06-15

    3,4-Dihydropyrimidin-2(1H)-ones were efficiently converted into the corresponding pyrimidin-2(1H)-ones in high yields within a short period of time on treatment with aqueous acetonitrile using 1,4-bis(triphenylphosphonium)-2-butene peroxodisulfate. Chemoselective oxidation of 3,4-dihydropyrimidin in the presence of other oxidizable functional groups was also achieved by this reagent.

  12. Ion and radical rearrangements as a probe of the mechanism of a surface reaction: The desulfurization of cyclopropylmethanethiol and 3-butene-1-thiol on Mo(110)

    Energy Technology Data Exchange (ETDEWEB)

    Wiegand, B.C.; Napier, M.E.; Friend, C.M. [Harvard Univ., Cambidge, MA (United States); Uvdal, P. [Lund Univ. (Sweden)

    1996-03-27

    Rearrangement reactions were used to probe the transient intermediates in thiol desulfurization induced by Mo(110) by studying cyclopropylmethanethiol and 3-butene-1-thiol. Thiolate intermediates were identified in both cases using vibrational spectroscopy, which indicates facile S-H bond scission on Mo(110). Heterolytic C-S bond scission, leading to a cationic intermediate, is excluded based on the lack of rearrangement products in the reactions of 3-butene-1-thiolate and the absence of cyclobutane or cyclobutene in the reaction of cyclopropylmethyl thiolate on Mo(110). Hydrogenolysis without rearrangement is the primary pathway for both thiols investigated. The lack of rearrangement in the 3-butene-1-thiolate indicates that C-S bond scission and C-H bond formation occur nearly simultaneously. Evidence for the radical pathway is obtained from the production of 1,3-butadiene formed via the rearrangement of cyclopropylmethyl group following C-S bond scission in the cyclopropylmethyl thiolate and by related studies of cyclopropylmethyl bromide. The investigation of the cyclopropylmethyl bromide also demonstrates that trapping of the cyclopropylmethyl radical is favored over selective {beta}-dehydrogenation. This is the first study in which radical rearrangements have been used to obtain detailed information about the nature of extremely short-lived reactions in a surface process. 39 refs., 5 figs., 3 tabs.

  13. 2-甲基-3-丁烯-2-醇合成3-甲基-2-丁烯-1-醇%Synthesis of 3-Methyl-2-butene-1-ol from 2-Methyl-3-butene-2-ol

    Institute of Scientific and Technical Information of China (English)

    颜延宁; 朱斌

    2011-01-01

    [Aims] 2-Methyl-3-buten-2-ol is a by-product from production of 3-methyl-2-buten-l-ol using method of isoprene indirect saponification. Waste recycling is an effective energy saving measure. [Methods] 3-Methyl-2-buten-l-ol was obtained by chlorination, esterification and saponification from 2-methyl-3-buten-2-ol. [Results] The results indicated that chlorination yield was 87.25% and esterification and saponification yield was 84.53% under optimal conditions. [Conclusions] The method is an effective method of reusing 2-methyl-3-buten-2-ol.%[目的]2-甲基-3-丁烯-2-醇是异戊二烯间接皂化法生产3-甲基-2-丁烯-1-醇过程中产生的副产物,废物回收再利用是节能减排的有效措施.[方法]2-甲基-3-丁烯-2-醇经氯化、酯化和皂化得到3-甲基-2-丁烯-1-醇.[结果]结果表明:在优化条件下,氯化反应的产率可达87.25%,酯化和皂化反应的产率可达84.53%.[结论]该方法是2-甲基-3-丁烯-2-醇再利用的有效方法.

  14. Synthesis of Lipid Based Polyols from 1-butene Metathesized Palm Oil for Use in Polyurethane Foam Applications

    Science.gov (United States)

    Sasidharan Pillai, Prasanth Kumar

    This thesis explores the use of 1-butene cross metathesized palm oil (PMTAG) as a feedstock for preparation of polyols which can be used to prepare rigid and flexible polyurethane foams. PMTAG is advantageous over its precursor feedstock, palm oil, for synthesizing polyols, especially for the preparation of rigid foams, because of the reduction of dangling chain effects associated with the omega unsaturated fatty acids. 1-butene cross metathesis results in shortening of the unsaturated fatty acid moieties, with approximately half of the unsaturated fatty acids assuming terminal double bonds. It was shown that the associated terminal OH groups introduced through epoxidation and hydroxylation result in rigid foams with a compressive strength approximately 2.5 times higher than that of rigid foams from palm and soybean oil polyols. Up to 1.5 times improvement in the compressive strength value of the rigid foams from the PMTAG polyol was further obtained following dry and/or solvent assisted fractionation of PMTAG in order to reduce the dangling chain effects associated with the saturated components of the PMTAG. Flexible foams with excellent recovery was achieved from the polyols of PMTAG and the high olein fraction of PMTAG indicating that these bio-derived polyurethane foams may be suitable for flexible foam applications. PMTAG polyols with controlled OH values prepared via an optimized green solvent free synthetic strategy provided flexible foams with lower compressive strength and higher recovery; i.e., better flexible foam potential compared to the PMTAG derived foams with non-controlled OH values. Overall, this study has revealed that the dangling chain issues of vegetable oils can be addressed in part using appropriate chemical and physical modification techniques such as cross metathesis and fractionation, respectively. In fact, the rigidity and the compressive strength of the polyurethane foams were in very close agreement with the percentage of terminal

  15. A shock tube and laser absorption study of ignition delay times and OH reaction rates of ketones: 2-Butanone and 3-buten-2-one

    KAUST Repository

    Badra, Jihad

    2014-03-01

    Ketones are potential biofuel candidates and are also formed as intermediate products during the oxidation of large hydrocarbons or oxygenated fuels, such as alcohols and esters. This paper presents shock tube ignition delay times and OH reaction rates of 2-butanone (C2H5COCH3) and 3-buten-2-one (C2H3COCH3). Ignition delay measurements were carried out over temperatures of 1100-1400K, pressures of 3-6.5atm, and at equivalence ratios (F{cyrillic}) of 0.5 and 1. Ignition delay times were monitored using two different techniques: pressure time history and OH absorption near 306nm. The reaction rates of hydroxyl radicals (OH) with these two ketones were measured over the temperature range of 950-1400K near 1.5atm. The OH profiles were monitored by the narrow-line-width ring-dye laser absorption of the well-characterized R1(5) line in the OH A-X (0, 0) band near 306.69nm. We found that the ignition delay times of 2-butanone and 3-buten-2-one mixtures scale with pressure as P-0.42 and P-0.52, respectively. The ignition delay times of 3-buten-2-one were longer than that of 2-butanone for stoichiometric mixtures, however, for lean mixtures (F{cyrillic}=0.5), 2-butanone had longer ignition delay times. The chemical kinetic mechanism of Serinyel et al. [1] over-predicted the ignition delay times of 2-butanone at all tested conditions, however, the discrepancies were smaller at higher pressures. The mechanism was updated with recent rate measurements to decrease discrepancy with the experimental data. A detailed chemistry for the oxidation of 3-buten-2-one was developed using rate estimation method and reasonable agreements were obtained with the measured ignition delay data. The measured reaction rate of 2-butanone with OH agreed well with the literature data, while we present the first high-temperature measurements for the reaction of OH with 3-buten-2-one. The following Arrhenius expressions are suggested over the temperature range of 950-1450K: kC2H5COCH3+OH=6.78×1013exp

  16. SIMULTANEOUS SAXS/WAXS/DSC STUDIES ON MICROSTRUCTURE OF CONVENTIONAL AND METALLOCENE-BASED ETHYLENE-BUTENE COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Jun-ting Xu; Bo-tao Li; Zhi-qiang Fan; Anthony J. Ryan

    2004-01-01

    The fractions of one metallocene-based (mPE) and one conventional (znPE) ethylene-butene copolymer eluted at 80-82℃ from temperature rising elution fractionation were selected for DSC and time-resolved small angle X-ray scattering (SAXS) and wide angle X-ray scattering (WAXS) characterization. The DSC and WAXS results show that two crystal structures exist in both mPE and znPE: structure A with higher melting temperature and structure B with lower melting temperature. It was found that original znPE (s-znPE) contains more highly ordered structure A than original mPE (s-mPE)in spite of the higher comonomer content of znPE. Another structure C is also identified because of higher crystallinity measured by WAXS than by DSC and is attributed to the interfacial region. The SAXS data were analyzed with correlation function and two maxima were observed in s-mPE and s-znPE, in agreement with the conclusion of two crystal populations drawn from DSC and WAXS results. These two crystal populations have close long periods in s-mPE, but very different long periods in s-znPE. In contrast, freshly crystallized mPE and znPE (f-mPE and f-znPE) contain only a single crystal population with a broader distribution of long period.

  17. ROLE AND IMPORTANCE OF RADIUS OF GYRATION OF CHAINS IN THE MELT IN THE CRYSTALIZATION OF POLY(1-BUTENE)

    Institute of Scientific and Technical Information of China (English)

    Qiang Fu; G.Strobl

    2002-01-01

    Crystallization in polymer systems actually is a process that transfers the entangled melts into a semi-crystalline layered structure. Whether or not a chain disentangles may result in different crystallization mechanism. When compared to the crystal thickness (dc), the volume occupied by the chain in the melt, i.e., the radius of gyration (Rg), plays a very important role in polymer crystallization. When dc ≤ Rg, crystallization does not necessitate a chain disentangling. The entanglements are just shifted into the amorphous regions. However, as dc>Rg, i.e., as the crystal thickness gets larger than the radius of gyration of the chain in the melt, it becomes necessary for a chain to disentangle. Then a change of crystallization mechanism occurs. Such change has been experimentally observed in the crystallization of poly(1-butene). A change in the crystal morphologies from spherulite to quadrangle, is seen via PLM, as crystallization temperatures increase.Even more, such a change is molecular weight dependent, and shifts to lower temperature as molecular weight decreases. There exists a jump of crystal thickness and crystallinity associated with morphological change, as seen via SAXS. A change of crystallization kinetics and crystallinity is further evidenced via dilatometry. The unique feature of P1b crystallization has been discussed based on the radius of gyration of chain in the melt (Rg), and very good agreement is obtained.

  18. Selective measurements of isoprene and 2-methyl-3-buten-2-ol based on NO+ ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    W. Jud

    2012-12-01

    Full Text Available Biogenic VOC emissions are often dominated by 2-methyl-1,3-butadiene (isoprene and 2-methyl-3-buten-2-ol (232 MBO. Here we explore the possibility to selectively distinguish these species using NO+ as a primary ion in a conventional PTR-MS equipped with an SRI unit. High purity of NO+ (>90% as a primary ion was utilized in laboratory and field experiments using a conventional PTR-TOF-MS. Isoprene is ionized via charge transfer leading to the major product ion C5H8+ (>99% (e.g. Spanel and Smith, 1998. 232 MBO undergoes a hydroxide ion transfer reaction resulting in the major product ion channel C5H9+ (>95% (e.g. Amelynck et al., 2005. We show that both compounds are ionized with little fragmentation (>5% under standard operating conditions. Typical sensitivities of 11.1 ± 0.1 (isoprene and 12.9 ± 0.1 (232 MBO ncps ppbv−1 were achieved, which correspond to limit of detections of 18 and 15 pptv respectively for a 10 s integration time. Sensitivities decreased at higher collisional energies. Calibration experiments showed little humidity dependence. We tested the setup at a field site in Colorado dominated by ponderosa pine, a 232 MBO emitting plant species. Our measurements confirm 232 MBO as the dominant biogenic VOC at this site, exhibiting typical average daytime concentrations between 0.2–1.4 ppbv. The method is able to detect the presence of trace levels of isoprene at this field site (90–250 ppt without any interference from 232 MBO, which would not be feasible using H3O+ ionization chemistry, and which currently also remains a challenge for other analytical techniques (e.g. gas chromatographic methods.

  19. Selective measurements of isoprene and 2-methyl-3-buten-2-ol based on NO+ ionization mass spectrometry

    Directory of Open Access Journals (Sweden)

    W. Jud

    2012-08-01

    Full Text Available Biogenic VOC emissions are often dominated by 2-methyl-1,3-butadiene (isoprene and 2-methyl-3-buten-2-ol (232 MBO. Here we explore the possibility for selectively distinguishing these species using NO+ as primary ion based on PTR-MS technology. High purity of NO+ (>90% as a primary ion was achieved in laboratory and field experiments using a PTR-TOF-MS. Isoprene is ionized via charge transfer leading to the major product ion C5H8+ (>99% (e.g. Spanel and Smith, 1998. 232 MBO undergoes a hydroxide ion transfer reaction resulting in the major product ion channel C5H9+ (>95% (e.g. Amelynck et al., 2005. We show that both compounds are ionized with little fragmentation (−1 were achieved, which correspond to limit of detections of 18 and 15 pptv, respectively for a 10 s integration time. Sensitivities decreased at higher collisional energies. Calibration experiments showed little humidity dependence. We tested the setup at a field site in Colorado dominated by ponderosa pine, a 232 MBO emitting plant species. Our measurements confirm 232 MBO as the dominant biogenic VOC at this site, exhibiting typical average daytime concentrations between 0.2–1.4 ppbv. The method is able to detect the presence of trace levels of isoprene (90–250 ppt without any interference from 232 MBO, which would not be feasible using H3O+ ionization chemistry, and which currently also remains achallenge for other analytical techniques (e.g. gas chromatographic methods.

  20. Formation of 1,4-dioxo-2-butene-derived adducts of 2′-deoxyadenosine and 2′-deoxycytosine in oxidized DNA

    OpenAIRE

    Chen, Bingzi; Vu, Choua C.; Byrns, Michael C.; Peter C. Dedon; Peterson, Lisa A.

    2006-01-01

    Oxidation of deoxyribose in DNA produces a variety of electrophilic residues that are capable of reacting with nucleobases to form adducts such as M1dG, the pyrimidopurinone adduct of dG. We now report that deoxyribose oxidation in DNA leads to the formation of oxadiazabicyclo(3.3.0)octaimine adducts of dC and dA. We previously demonstrated that these adducts arise in reactions of nucleosides and DNA with trans-1,4-dioxo-2-butene, the β-elimination product of the 2-phosphoryl-1,4-dioxobutane ...

  1. Synthesis and Characterization of a Ru(II Complex with Functionalized Phenanthroline Ligands Having Single-Double Linked Anthracenyl and 1-Methoxy-1-buten-3-yne Moieties

    Directory of Open Access Journals (Sweden)

    Adewale O. Adeloye

    2010-10-01

    Full Text Available Two series of bidentate polypyridine ligands, made of phenanthroline chelating subunits having substituted mono-and di-anthracenyl groups, and 1-methoxy-1-buten-3-yne at the 4 and 7-positions with the corresponding heteroleptic Ru(II complex have been synthesized and characterized. The complex is formulated as [(Ru(L1(L2(NCS2], (where L1 = 4-(9-dianthracenyl-10-(2,3-dimethylacrylic acid-7-(9-anthracenyl-10-(2,3-dimethylacrylic acid-1,10-phenanthroline and L2 = 4,7-bis(1-methoxy-1-buten-3-yne-1,10-phenanthroline. The Ru(II complex shows characteristic broad and intense metal-to-ligand charge transfer (MLCT bands absorption and appreciable photoluminescence spanning the visible region. The ligands and complex were characterized by FT-IR, 1H, 13C NMR spectroscopy, UV-Vis, photoluminescence and elemental analysis (see in supplementary materials. The anchoring groups in both ligands have allowed an extended delocalization of acceptor orbital of the metal-to-ligand charge-transfer (MLCT excited state.

  2. Isobutane/2-butene alkylation in Y zeolite exchange with metallic ions; Alquilacao de isobutano com 2-buteno em zeolita Y trocada com ions metalicos

    Energy Technology Data Exchange (ETDEWEB)

    Rosenbach Junior, Nilton; Mota, Claudio J.A. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Quimica]. E-mail: cmota@iq.ufrj.br

    2003-07-01

    In industrial scale-process, isobutane/2-butene alkylation has been normally achieved under strong acids conditions, using HF or H{sub 2}SO{sub 4} as catalysts. Nevertheless, this acids present problems such as high consumption and environmental risk. Therefore, there is a strong interest in substituting them by solid catalysts. However, over solid acids, there is a fast deactivation, usually attributed to oligomerization, occurring on Broensted sites, that preferentially adsorb the unsaturated hydrocarbons. This study shows that the reaction can occur on zeolites Y without Broensted acid sites, using an alkyl halide as initiator, added to the feed in the initial moments of the reaction. In this approach the oligomerization problem is minimized. The reactions were carried out in liquid phase at 50 deg C and 450 lb/in{sup 2}, using a mixture of isobutene/2-butene with a molar fraction of 10:1. Catalyst activity and selectivity to trimethylpentane and dimethylhexane for the Y zeolite exchange with Ag{sup +}, Cu{sup ++} and Fe{sup +++} were followed by on line capillary gas chromatography. For comparison purpose, the reaction was also carried out on a HUSY zeolite. All cation-exchanged zeolite presented a better performance than the protonic zeolite. The best performance was of the Y zeolite exchange with Ag{sup +}, followed by Cu{sup ++} and Fe{sup +++} exchanged zeolites. (author)

  3. Review on Synthesis of 1,1,1,4,4,4 - Hexafluoro - 2 - Butene%六氟-2-丁烯的合成研究进展

    Institute of Scientific and Technical Information of China (English)

    付庆; 孙晓刚; 向绍基; 孔小林

    2012-01-01

    1,1,1,4,4,4 - Hexafluoro - 2 - Butene is a halon alternative. Its properties on ozone depletion po- tential ( ODP = 0 ), global warming potential ( GWP10o yr ~TH = 9. 4 (NOAA) ) are superior to other halon alterna- tives. This paper is a review on synthesis of 1,1,1,4,4,4 - hexafluoro - 2 - butene, and indicates that the route of R1316 as a raw material may be an industrial strategy.%六氟-2-丁烯(HFC-1336)ODP值为零,GWP值很低(GWP100ryITH=9.4(NOAA)),是发泡剂HCFC-141b的理想替代品之一。对其合成方法进行了文献综述,在文献基础上得出以六氟-2,3-二氯-2-丁烯(R1316)为原料经两步反应合成HFC-1336的工艺具有工业化应用前景。

  4. Theoretical investigation of the hydrogen shift reactions in peroxy radicals derived from the atmospheric decomposition of 3-methyl-3-buten-1-ol (MBO331)

    DEFF Research Database (Denmark)

    Knap, Hasse Christian; Jørgensen, Solvejg; Kjærgaard, Henrik Grum

    2015-01-01

    The hydroxy peroxy radical derived from the oxidation of 3-methyl-3-buten-1-ol (MBO331), can undergo four different hydrogen shift (H-shift) reactions. We have compared optimized geometries, barrier heights and reaction rate constants obtained with five different DFT functionals (BLYP, B3LYP, BHand......HLYP, wB97X-D and M06-2X) with the aug-cc-pVTZ basis set. We found that the single-point CCSD(T)-F12A/VDZ-F12 energies calculated at the different DFT geometries had very similar barrier heights. The wB97X-D, M06-2X and CCSD(T)-F12A/VDZ-F12 barrier heights are comparable. The atmospheric decomposition of...... the MBO331 peroxy radical was found to undergo a 1,5-CH H-shift reaction with a reaction rate constant of about 1 s-1....

  5. Three-dimensional observation of the phase structure of high density polyethylene (HDPE)/poly(ethylene-co-butene) (PEB) blend by laser scanning confocal microscopy

    Institute of Scientific and Technical Information of China (English)

    ZHANG ChengGui; DONG Xia; WANG DuJin; HAN Charles C

    2007-01-01

    In this paper, high density polyethylene (HDPE)/poly(ethylene-co-butene) (PEB) blend (50/50 wt%) was prepared through solution blending and then compression molding, and subsequently examined by laser scanning confocal microscopy (LSCM). The PEB used in this experiment was labeled with a small quantity of a fluorescein derivative to render fluorescence. The initial films showed uniform dye distribution and no indication of phase separation within the resolution of optical microscopy. Sample films annealing at 140℃ followed by rapid cooling to room temperature showed obvious phase separation and bicontinuous structure. The present work indicates that by labeling one component with fluorescein derivative, LSCM can efficiently perform in situ depth profiling of polymer blends.

  6. Development of analytical methods for the gas chromatographic determination of 1,2-epoxy-3-butene, 1,2:3,4-diepoxybutane, 3-butene-1,2-diol, 3,4-epoxybutane-1,2-diol and crotonaldehyde from perfusate samples of 1,3-butadiene exposed isolated mouse and rat livers

    Energy Technology Data Exchange (ETDEWEB)

    Bhowmik, S.; Schuster, A.; Filser, J.G.

    2003-07-01

    Mutagenicity and carcinogenicity of 1,3-butadiene (BD) highly probably results from epoxide metabolites as 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB) and 3,4-epoxybutane-1,2-diol (EBD). A further metabolite crotonaldehyde (CA) has also been discussed to be relevant. So far, in BD exposed rodents only EB and DEB concentrations had been quantified. However, the methods used were either not very sensitive or instrumentally expensive. Therefore, the goal of the present work was to establish simple analytical methods selective and sensitive enough to determine all of these compounds and a further secondary BD intermediate, 3-butene-1,2-diol (B-diol), in BD exposed rodent livers. The once-through perfused liver system was chosen for testing the applicability of the methods to be developed, since it enables BD exposures of this quantitatively most relevant metabolising organ near to the in-vivo situation. All the metabolites were extracted from the aqueous perfusion medium and analysed using a gas chromatograph equipped with a mass selective detector (GC/MS) in the PCI mode. (orig.)

  7. Synthesis and in vivo evaluation of (E)-N-[{sup 11}C]Methyl-4- (3-pyridinyl)-3-butene-1-amine ([{sup 11}C]metanicotine) as a nicotinic receptor radioligand

    Energy Technology Data Exchange (ETDEWEB)

    Brown-Proctor, Clive; Snyder, Scott E.; Sherman, Phillip S.; Kilbourn, Michael R. E-mail: mkilbour@umich.edu

    2000-05-01

    (E)-N-[{sup 11}C]Methyl-4-(3-pyridinyl)-3-butene-1-amine ([{sup 11}C]metanicotine), a high affinity (K{sub i}=16 nM) CNS-selective nicotinic agonist, was prepared by the [{sup 11}C]alkylation of the desmethyl precursor with [{sup 11}C]methyl trifluoromethanesulfonate. In vivo distribution studies in mice demonstrated good blood brain permeability but essentially uniform regional brain distribution and no evidence of specific binding to nicotinic cholinergic receptors. Identical results were obtained in an imaging study performed in a monkey brain. Therefore, despite literature reports supporting the use of metanicotine as a cognition enhancing nicotinic agonist, (E)-N-[{sup 11}C]methyl-4-(3-pyridinyl)-3-butene-1-amine does not appear to be a suitable candidate for in vivo imaging studies of nicotinic acetylcholine receptors in the mammalian brain.

  8. The cross-metathesis of methyl oleate with cis-2-butene-1,4-diyl diacetate and the influence of protecting groups

    Directory of Open Access Journals (Sweden)

    Jessica Pérez Gomes

    2011-01-01

    Full Text Available Background: α,ω-Difunctional substrates are useful intermediates for polymer synthesis. An attractive, sustainable and selective (but as yet unused method in the chemical industry is the oleochemical cross-metathesis with preferably symmetric functionalised substrates. The current study explores the cross-metathesis of methyl oleate (1 with cis-2-butene-1,4-diyl diacetate (2 starting from renewable resources and quite inexpensive base chemicals.Results: This cross-metathesis reaction was carried out with several phosphine and N-heterocyclic carbene ruthenium catalysts. The reaction conditions were optimised for high conversions in combination with high cross-metathesis selectivity. The influence of protecting groups present in the substrates on the necessary catalyst loading was also investigated.Conclusions: The value-added methyl 11-acetoxyundec-9-enoate (3 and undec-2-enyl acetate (4 are accessed with nearly quantitative oleochemical conversions and high cross-metathesis selectivity under mild reaction conditions. These two cross-metathesis products can be potentially used as functional monomers for diverse sustainable polymers.

  9. Inhibitory effect of a tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal on amyloid-β generation and inflammatory reactions via inhibition of NF-κB and STAT3 activation in cultured astrocytes and microglial BV-2 cells

    Directory of Open Access Journals (Sweden)

    Choi Im Seup

    2011-10-01

    Full Text Available Abstract Background Amyloidogenesis is linked to neuroinflammation. The tyrosine-fructose Maillard reaction product, 2,4-bis(p-hydroxyphenyl-2-butenal, possesses anti-inflammatory properties in cultured macrophages, and in an arthritis animal model. Because astrocytes and microglia are responsible for amyloidogenesis and inflammatory reactions in the brain, we investigated the anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl-2-butenal in lipopolysaccharide (LPS-stimulated astrocytes and microglial BV-2 cells. Methods Cultured astrocytes and microglial BV-2 cells were treated with LPS (1 μg/ml for 24 h, in the presence (1, 2, 5 μM or absence of 2,4-bis(p-hydroxyphenyl-2-butenal, and harvested. We performed molecular biological analyses to determine the levels of inflammatory and amyloid-related proteins and molecules, cytokines, Aβ, and secretases activity. Nuclear factor-kappa B (NF-κB DNA binding activity was determined using gel mobility shift assays. Results We found that 2,4-bis(p-hydroxyphenyl-2-butenal (1, 2, 5 μM suppresses the expression of inducible nitric oxide synthase (iNOS and cyclooxygenase-2 (COX-2 as well as the production of nitric oxide (NO, reactive oxygen species (ROS, tumor necrosis factor-α (TNF-α, and interleukin-1β (IL-1β in LPS (1 μg/ml-stimulated astrocytes and microglial BV-2 cells. Further, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited the transcriptional and DNA binding activity of NF-κB--a transcription factor that regulates genes involved in neuroinflammation and amyloidogenesis via inhibition of IκB degradation as well as nuclear translocation of p50 and p65. Consistent with the inhibitory effect on inflammatory reactions, 2,4-bis(p-hydroxyphenyl-2-butenal inhibited LPS-elevated Aβ42 levels through attenuation of β- and γ-secretase activities. Moreover, studies using signal transducer and activator of transcription 3 (STAT3 siRNA and a pharmacological inhibitor showed that 2

  10. Protection of rats against 3-butene-1,2-diol-induced hepatotoxicity and hypoglycemia by N-acetyl-L-cysteine

    International Nuclear Information System (INIS)

    3-Butene-1,2-diol (BDD), an allylic alcohol and major metabolite of 1,3-butadiene, has previously been shown to cause hepatotoxicity and hypoglycemia in male Sprague-Dawley rats, but the mechanisms of toxicity were unclear. In this study, rats were administered BDD (250 mg/kg) or saline, ip, and serum insulin levels, hepatic lactate levels, and hepatic cellular and mitochondrial GSH, GSSG, ATP, and ADP levels were measured 1 or 4 h after treatment. The results show that serum insulin levels were not causing the hypoglycemia and that the hypoglycemia was not caused by an enhancement of the metabolism of pyruvate to lactate because hepatic lactate levels were either similar (1 h) or lower (4 h) than controls. However, both hepatic cellular and mitochondrial GSH and GSSG levels were severely depleted 1 and 4 h after treatment and the mitochondrial ATP/ADP ratio was also lowered 4 h after treatment relative to controls. Because these results suggested a role for hepatic cellular and mitochondrial GSH in BDD toxicity, additional rats were administered N-acetyl-L-cysteine (NAC; 200 mg/kg) 15 min after BDD administration. NAC treatment partially prevented depletion of hepatic cellular and mitochondrial GSH and preserved the mitochondrial ATP/ADP ratio. NAC also prevented the severe depletion of serum glucose concentration and the elevation of serum alanine aminotransferase activity after BDD treatment without affecting the plasma concentration of BDD. Thus, depletion of hepatic cellular and mitochondrial GSH followed by the decrease in the mitochondrial ATP/ADP ratio was likely contributing to the mechanisms of hepatotoxicity and hypoglycemia in the rat

  11. Development of three stable isotope dilution assays for the quantitation of (E)-2-butenal (crotonaldehyde) in heat-processed edible fats and oils as well as in food.

    Science.gov (United States)

    Granvogl, Michael

    2014-02-12

    Three stable isotope dilution assays (SIDAs) were developed for the quantitation of (E)-2-butenal (crotonaldehyde) in heat-processed edible fats and oils as well as in food using synthesized [¹³C₄]-crotonaldehyde as internal standard. First, a direct headspace GC-MS method, followed by two indirect methods on the basis of derivatization with either pentafluorophenylhydrazine (GC-MS) or 2,4-dinitrophenylhydrazine (LC-MS/MS), was developed. All methods are also suitable for the quantitation of acrolein using the standard [¹³C₃]-acrolein. Applying these three methods on five different types of fats and oils varying in their fatty acid compositions revealed significantly varying crotonaldehyde concentrations for the different samples, but nearly identical quantitative data for all methods. Formed amounts of crotonaldehyde were dependent not only on the type of oil, e.g., 0.29-0.32 mg/kg of coconut oil or 33.9-34.4 mg/kg of linseed oil after heat-processing for 24 h at 180 °C, but also on the applied temperature and time. The results indicated that the concentration of formed crotonaldehyde seemed to be correlated with the amount of linolenic acid in the oils. Furthermore, the formation of crotonaldehyde was compared to that of its homologue acrolein, demonstrating that acrolein was always present in higher amounts in heat-processed oils, e.g., 12.3 mg of crotonaldehyde/kg of rapeseed oil in comparison to 23.4 mg of acrolein/kg after 24 h at 180 °C. Finally, crotonaldehyde was also quantitated in fried food, revealing concentrations from 12 to 25 μg/kg for potato chips and from 8 to 19 μg/kg for donuts, depending on the oil used.

  12. Study on a Controllable Oxidative Dehydrogenation of Butene in a Novel Inorganic Membrane Reactor%膜控制氧化反应器中丁烯氧化脱氢的研究

    Institute of Scientific and Technical Information of China (English)

    李志华; 刘长厚; 王连军; 葛善海

    2001-01-01

    在气体均布的无机膜控制氧化反应器上进行了丁烯氧化脱氢制丁二烯反应,并将其与固定床方式反应的实验结果进行了对比,结果表明在实验范围内膜反应器比传统的固定床反应更为有效。建立了描述控制氧化膜反应器操作性能的数学模型,并将模型求解值与实验值对比,吻合良好。%Controllable oxidative dehydrogenation of butene to butadiene was carried out in a novel inorganic membrane reactor(IMR) with oxygen uniform distribution. In this reactor butene and air (oxygen) were introduced into the two sides of the membrane separately. By means of adjusting the pressure difference across the membrane the permeation of air into the reaction region was controllable. The main reaction was promoted and the excessive oxidation of the hydrocarbons is eliminated. The experimental result showed that both the yield and selectivity of the butadiene obtained in the IMR were higher than those obtained in FBR obviously. The kinetic equations of oxidative dehydrogenation of butene over a ferrite catalyst were suggested and the mathematical model for simulating the operation characteristic of IMR was derived. The simulating results agree well with the experimental results. It appears that this kind of reactor can be used for other oxidation reactions.

  13. Study of ethylene/2-butene cross-metathesis over W-H/Al2O 3 for propylene production: Effect of the temperature and reactant ratios on the productivity and deactivation

    KAUST Repository

    Mazoyer, Etienne

    2013-05-01

    A highly active and selective catalyst based on supported tungsten hydride for the cross-metathesis between ethylene and 2-butenes yielding propylene has been investigated at low pressure with various temperatures and feed ratios. At low temperature (120 °C), the catalyst deactivates notably with time on stream. This phenomenon was extensively examined by DRIFTS, TGA, DSC, and solid-state NMR techniques. It was found that a large amount of carbonaceous species were formed due to a side-reaction such as olefin polymerization which took place simultaneously with the metathesis reaction. However, at 150 °C, the catalyst was stable with time and thereby gave a high productivity in propylene. Importantly, the slight increase in temperature clearly disfavored the side reaction. The ratio of ethylene to trans-2-butene was also studied, and surprisingly, the W-H/Al2O3 catalyst is stable and highly selective to propylene even at substoichiometric ethylene ratios. © 2013 Elsevier Inc. All rights reserved.

  14. Evaluation of HOx sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated ecosystem

    Directory of Open Access Journals (Sweden)

    S. B. Henry

    2013-02-01

    Full Text Available We present a detailed analysis of OH observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-ROCS (Rocky Mountain Organic Carbon Study 2010 field campaign at the Manitou Forest Observatory (MFO, which is a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 4. When the UWCM calculation is constrained by measured HO2, model calculated OH is in better agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying unknown HO2

  15. Evaluation of HOx sources and cycling using measurement-constrained model calculations in a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated ecosystem

    Directory of Open Access Journals (Sweden)

    S. B. Henry

    2012-06-01

    Full Text Available We present a detailed analysis of OH and HO2 observations from the BEACHON (Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-ROCS (Rocky Mountain Organic Carbon Study 2010 field campaign at the Manitou Forest Observatory (MFO, which is a 2-methyl-3-butene-2-ol (MBO and monoterpene (MT dominated forest environment. A comprehensive suite of measurements was used to constrain primary production of OH via ozone photolysis, OH recycling from HO2, and OH chemical loss rates, in order to estimate the steady-state concentration of OH. In addition, the University of Washington Chemical Model (UWCM was used to evaluate the performance of a near-explicit chemical mechanism. The diurnal cycle in OH from the steady-state calculations is in good agreement with measurement. A comparison between the photolytic production rates and the recycling rates from the HO2 + NO reaction shows that recycling rates are ~20 times faster than the photolytic OH production rates from ozone. Thus, we find that direct measurement of the recycling rates and the OH loss rates can provide accurate predictions of OH concentrations. More importantly, we also conclude that a conventional OH recycling pathway (HO2 + NO can explain the observed OH levels in this non-isoprene environment. This is in contrast to observations in isoprene-dominated regions, where investigators have observed significant underestimation of OH and have speculated that unknown sources of OH are responsible. The highly-constrained UWCM calculation under-predicts observed HO2 by as much as a factor of 8. As HO2 maintains oxidation capacity by recycling to OH, UWCM underestimates observed OH by as much as a factor of 5. When the UWCM calculation is constrained by measured HO2, model calculated OH is in reasonable agreement with the observed OH levels. Conversely, constraining the model to observed OH only slightly reduces the model-measurement HO2 discrepancy, implying

  16. Experiment and Modeling of Pure and Binary Adsorption of n-Butane and Butene-1 on ZSM-5 Zeolites with Different Si/Al Ratios%正丁烷及丁烯-1在不同硅铝比ZSM-5分子筛上吸附的实验与模型

    Institute of Scientific and Technical Information of China (English)

    王斐; 汪文川; 黄世萍; 滕加伟; 谢在库

    2007-01-01

    Four ZSM-5 zeolite catalysts with different Si/Al ratios for the catalytic cracking of C4 fractions to produce ethylene and propylene were prepared in this study.First, the adsorption isotherms of pure n-butane and butene-1 and their mixtures on these catalysts at 300K and p=0-100kPa were measured using the intelligent gravimetric analyzer.The experimental results indicate that the presence of Al can significantly affect the adsorption of butene-1 than that of n-butane on ZSM-5 zeolites.Then, the double Langmuir (DL) model was applied to study the pure gas adsorption on ZSM-5 zeolites for pure n-butane and butene-1.By combining the DL model with the ideal adsorbed solution theory (IAST), the IAST-DL model was applied to model the butene-1 (l)/n-butane (2) binary mixture adsorption on ZSM-5 zeolites with different Si/Al ratios.The calculated results are in good agreement with the experimental data, indicating that the IAST-DL model is effective for the present systems.Finally, the adsorption over a wide range of variables was predicted at low pressure and 300K by the model proposed.It is found that the selectivity of butene-1 over n-butane increases linearly with the decrease of Si/Al ratio.A correlation between the selectivity and Si/Al ratio of the sample was proposed at 300K and p=0.08MPa.

  17. SOA formation from the atmospheric oxidation of 2-methyl-3-buten-2-ol and its implications for PM2.5

    Directory of Open Access Journals (Sweden)

    W. A. Lonneman

    2012-02-01

    Full Text Available The formation of secondary organic aerosol (SOA generated by irradiating 2-methyl-3-buten-2-ol (MBO in the presence and/or absence of NOx, H2O2, and/or SO2 was examined. Experiments were conducted in smog chambers operated in either dynamic or static mode. A filter/denuder sampling system was used for simultaneously collecting gas- and particle-phase products. The structural characterization of gas and particulate products was investigated using BSTFA, BSTFA + PFBHA, and DNPH derivatization techniques followed by GC-MS and liquid chromatography analysis. This analysis showed the occurrence of more than 68 oxygenated organic compounds in the gas and particle phases, 28 of which were tentatively identified. The major components observed include 2,3-dihydroxyisopentanol (DHIP, 2-hydroxy-2-oxoisopentanol, 2,3-dihydroxy-3-methylbutanal, 2,3-dihydroxy-2-methylsuccinic acid, 2-hydroxy-2-methylpropanedioic acid, acetone, glyoxal, methylglyoxal, glycolaldehyde, and formaldehyde. Most of these oxygenated compounds were detected for the first time in this study. While measurements of the gas-phase photooxidation products have been made, the focus of this work has been an examination of the particle phase. SOA from some experiments was analyzed for the organic mass to organic carbon ratio (OM/OC, the effective enthalpy of vaporization (ΔHvapeff, and the aerosol yield. Additionally, aerosol size, volume, and number concentrations were measured by a Scanning Mobility Particle Sizer coupled to a Condensation Particle Counter system. The OM/OC ratio was 2.1 in the MBO/H2O2 system. The ΔHvapeff was 41 kJ mol−1, a value similar to that of isoprene SOA. The laboratory SOA yield measured in this study was 0.7% in MBO/H2O2 for an aerosol mass of 33 μg m−3. Secondary organic aerosol was found to be negligible under conditions with oxides of nitrogen (NOx present. Time profiles and proposed reaction schemes are provided for selected compounds. The contribution

  18. Oxidation of butane and butene on the (100) face of (VO) sub 2 P sub 2 O sub 7 : A dynamic view in terms of the crystallochemical model of active sites

    Energy Technology Data Exchange (ETDEWEB)

    Ziolkowski, J. (Institute of Catalysis and Surface Chemistry, Krakow (Poland)); Bordes, E.; Courtine, P. (Universite de Technologie de Compiegne (France))

    1990-03-01

    The structure of the (100) face of (VO){sub 2}P{sub 2}O{sub 7} and its performance in the oxidation of n-butane and butenes to maleic anhydride have been analyzed in terms of the crystallochemical model of active sites (CMAS). Analysis involves the heats of adsorption of oxygen, hydrogen (as a component of OH), and water as well as the heats of their movement along the surface, which allows determination of the energetically easiest pathways of elementary steps and gives insight into the reaction dynamics. The catalyst (100) (VO){sub 2}P{sub 2}O{sub 7} is found to work in a surface-oxidized state, all cations being covered with oxygen. The active site for the direct oxidation of n-butane to maleic anhydride is found to be situated between four protruding, undersaturated oxygens (2 {times} V-O, 2 {times} P-O). The reaction is thought to be initiated by H bonding at both terminal carbons. The desorption of water and migration of surface oxygen (which produces the pairs of adjacent vacancies to be filled by O{sub 2} molecules) that constitute a substep of the concerted reoxidation seem to be rate determining. Oxidation of butenes on (100) (VO){sub 2}P{sub 2}O{sub 7} is thought to be initiated by adsorption of C{double bond}C over unsaturated oxygens. In view of the surface structure, this adsorption limits the number of active oxygens with which the hydrocarbon may interact and favors a mild and nonselective oxidation to epoxybutanes, crotonaldehyde, hydrofuran, furan, and acetaldehyde. Minor yields are expected due to difficult reoxidation and competitive adsorption. Theoretical predictions are shown to agree with experimental data.

  19. 2-甲基-3-丁烯-2-醇+直链一元醇二元体系的过量摩尔体积和表观摩尔体积298.15 K)%Excess Molar Volume and Apparent Molar Volume of Binary Mixtures of 2-Methyl-3-buten-2-ol with 1-Alcohol at 298.15 K

    Institute of Scientific and Technical Information of China (English)

    刘迪霞; 李浩然; 邓东顺; 韩世钧

    2002-01-01

    Excess molar volumes (VEm) of binary mixtures of 2-methyl-3-buten-2-ol [CH3C(OH)(CH3)CHCH2]with four 1-alcohols: methanol, ethanol, 1-propanol and 1-butanol at 298.15 K and atmospheric pressure are derived from density measurements with a vibrating-tube densimeter. All the excess volumes are negative in the systems over the entire composition range. The results are correlated with the Redlich-Kister equation. The effects of chain length of 1-alcohols on VmE are discussed. The apparent molar volumes of 2-methyl-3-buten-2-ol and 1-alcohols are calculated respectively.

  20. Effects of post treatment of HZSM-5 zeolites on catalytic cracking of butene%后处理改性对HZSM-5沸石丁烯裂解性能的影响

    Institute of Scientific and Technical Information of China (English)

    张荣荣; 王正宝

    2015-01-01

    The structure and acidity of HZSM-5 zeolites were modified using different post treatment methods: alkaline treatment, steam treatment, and alkaline-steaming treatment. The catalytic performances of modified zeolites were tested in 1-butene catalytic cracking. Their physicochemical properties were characterized by N2 adsorption, scanning electron microscopy (SEM), X-ray diffraction (XRD), and infrared spectroscopy with pyridine adsorption (Py-IR). The acidities of zeolites increased after the alkaline treatment, and as a result, the activity of butene cracking increased and the selectivity of propylene decreased. However, the deactivation rate of alkaline-treated zeolites had no significant change. There was a pronounced development of mesopores (5—20 nm) with a broad pore-size distribution in alkaline-treated ZSM-5 zeolites. Mesopores (2—4 nm) with a narrow distribution is observed after steaming treatment, while the mesopore volume is low. Zeolites after alkaline- and steaming-treatment showed two kinds of mesopore distributions, 2—4 nm (narrow) and 5—20 nm (broad). Due to the decrease of Brønsted acidic sites, the selectivity of propylene increased over ZSM-5 zeolites with any of the post treatments; a relatively stable propylene yield was obtained after the reaction of 2.5 h (except for zeolites treated with high concentration of alkaline followed by steaming treatment).%采用不同后处理手段(碱处理、水汽处理以及碱处理-水汽处理)对HZSM-5沸石的孔结构和酸性质进行了调变,并对其丁烯裂解性能进行了研究。运用N2吸脱附、扫描电镜(SEM)、X射线衍射(XRD)以及吡啶吸附红外(Py-IR)对后处理改性前后的沸石样品的物理化学性质进行了表征。碱处理后HZSM-5的质子酸量增加,在5~20 nm处具有分布较宽的介孔,其反应活性升高,丙烯选择性下降,但失活速率没有加快。单独水汽处理在2~4 nm处产生介孔,但介孔体

  1. Thermodynamic Calculation and Analysis of Converting Butene to Butadiene by Oxidative Dehydrogenation%丁烯氧化脱氢制丁二烯体系的热力学计算与分析

    Institute of Scientific and Technical Information of China (English)

    程亮亮; 黄剑锋; 马应海

    2015-01-01

    In the reaction system of converting butene to butadiene by oxidative dehydrogenation, the standard enthalpy, the gibbs free energy and the equilibrium constants of each reaction were calculated. The equilibrium composition of the reaction system was calculated by the principle of Gibbs free energy minimization. The results show that the oxidative dehydrogenation reaction and the complete oxidation reaction can both proceed completely, but the yield of butadiene can be limited by the thermodynamic equilibrium. Therefore, in order to improve the yield of butadiene, it is crucial to develop catalysts with high performance, and the generation reaction of COx can be completely inhibited by kinetically controlling.%计算了正丁烯氧化脱氢制丁二烯体系中各反应的标准摩尔反应焓、标准摩尔吉布斯自由能、平衡常数,并利用 Gibbs 自由能最小法计算了反应体系的热力学平衡组成。结果表明,正丁烯的氧化脱氢与完全氧化反应在热力学上均可完全进行,但是丁二烯的产率受热力学平衡限制。因此,提高丁二烯产率的关键在于开发高性能的催化剂,从动力学上角度充分抑制 COx的生成反应。

  2. Anti-inflammatory and anti-amyloidogenic effects of a small molecule, 2,4-bis(p-hydroxyphenyl-2-butenal in Tg2576 Alzheimer’s disease mice model

    Directory of Open Access Journals (Sweden)

    Jin Peng

    2013-01-01

    Full Text Available Abstract Background Alzheimer’s disease (AD is pathologically characterized by excessive accumulation of amyloid-beta (Aβ fibrils within the brain and activation of astrocytes and microglial cells. In this study, we examined anti-inflammatory and anti-amyloidogenic effects of 2,4-bis(p-hydroxyphenyl-2-butenal (HPB242, an anti-inflammatory compound produced by the tyrosine-fructose Maillard reaction. Methods 12-month-old Tg2576 mice were treated with HPB242 (5 mg/kg for 1 month and then cognitive function was assessed by the Morris water maze test and passive avoidance test. In addition, western blot analysis, Gel electromobility shift assay, immunostaining, immunofluorescence staining, ELISA and enzyme activity assays were used to examine the degree of Aβ deposition in the brains of Tg2576 mice. The Morris water maze task was analyzed using two-way ANOVA with repeated measures. Otherwise were analyzed by one-way ANOVA followed by Dunnett’s post hoc test. Results Treatment of HPB242 (5 mg/kg for 1 month significantly attenuated cognitive impairments in Tg2576 transgenic mice. HPB242 also prevented amyloidogenesis in Tg2576 transgenic mice brains. This can be evidenced by Aβ accumulation, BACE1, APP and C99 expression and β-secretase activity. In addition, HPB242 suppresses the expression of inducible nitric oxide synthase (iNOS and cyclooxygenase-2 (COX-2 as well as activation of astrocytes and microglial cells. Furthermore, activation of nuclear factor-kappaB (NF-κB and signal transducer and activator of transcription 1/3 (STAT1/3 in the brain was potently inhibited by HPB242. Conclusions Thus, these results suggest that HPB242 might be useful to intervene in development or progression of neurodegeneration in AD through its anti-inflammatory and anti-amyloidogenic effects.

  3. (顺)-1,1,1,4,4,4-六氟-2-丁烯的合成研究进展%Progress of preparation of cis-hexafluoro-2-butene

    Institute of Scientific and Technical Information of China (English)

    赵波; 吕剑

    2014-01-01

    作为氢氟烯烃(HFO)类物质,顺-1,1,1,4,4,4-六氟-2-丁烯(Z-HFO-1336)的臭氧消耗潜值(ODP)为零,温室效应潜值(GWP)极低,对环境影响很小,因其性能与前几代发泡剂相近,被看作新一代绿色环保发泡剂,其合成方法受到氟化工界的广泛关注。至今,Z-HFO-1336的合成方法主要可分为:①直接氟化C4化合物合成;②氟利昂类化合物CFC-113、HCFC-123经偶联反应制备;③由卤代甲烷与卤代烯烃经调聚反应制备。其中直接氟化法虽然路线短,但产物选择性低、催化剂稳定性差;而氟利昂类化合物偶联法污染大,调聚合成存在工艺复杂、收率低等问题。提出了两种具有学术和工业价值的研究路线:①HCFC-123自偶联一步合成Z-HFO-1336,反应涉及C-Cl键的活化、单电子转移(SET)等过程,极具理论研究意义;②以乙烯、三氟丙烯为原料经调聚反应合成,原料来源广泛,催化合成可连续进行,具有很强的工业价值。%Hydrofluoroolefin cis-1,1,1,4,4,4-hexafluoro-2-butene (Z-HFO-1336) has zero ozone depletion potential (ODP) and low global warming potential (GWP) , which replaces trichlorofluoromethane CFC-11 , 1,1-dichloro-1-fluoroethane HCFC-141b , and 1,1,1,3,3-pentafluoropropane HFC-245fa by good compatibility and chemical stability,is used as new generation foaming materials. Synthesis of the compound mainly includes three types:direct fluorination of C4 compounds,coupling of CFC-113 and HCFC-123,and telomerization of haloalkane with olefin to form chlorofluorobutane by Kharasch reaction. Direct method is too expensive for large scale production, coupling route brings up pollution problems,and complicated Kharasch reaction involves long steps. Two synthesis approaches are proposed:Coupling of HCFC-123 attracts theoretical study,which involves activation of C─Cl bond and single electron transfer process,and simple and practical way using

  4. Henry's law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol

    International Nuclear Information System (INIS)

    Henry's law constants and infinite dilution activity coefficients of cis-2-butene, dimethylether, chloroethane, and 1,1-difluoroethane in methanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, isobutanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol, and 2-methyl-2-butanol in the temperature range of 250 K to 330 K were measured by a gas stripping method and partial molar excess enthalpies were calculated from the activity coefficients. A rigorous formula for evaluating the Henry's law constants from the gas stripping measurements was used for the data reduction of these highly volatile mixtures. The uncertainty is about 2% for the Henry's law constants and 3% for the estimated infinite dilution activity coefficients. In the evaluation of the infinite dilution activity coefficients, the nonideality of the solute such as the fugacity coefficient and Poynting correction factor cannot be neglected, especially at higher temperatures. The estimated uncertainty of the infinite dilution activity coefficients includes 1% for nonideality

  5. Influence of Tungsten Loadings on the 1-Butene Metathesis Reaction over W/SiO2/Al2O3 Catalysts%钨含量对W/SiO2/Al2O3催化剂上1-丁烯自歧化反应的影响

    Institute of Scientific and Technical Information of China (English)

    柳娜; 张辉; 薛念华; 丁维平

    2015-01-01

    A series of W/SiO2/Al2O3 catalysts with various tungsten loadings were synthesized via the impregnation method. The as-synthesized catalysts were characterized by X-ray diffraction (XRD), Raman spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, H2 temperature-programmed reduction (H2-TPR), and NH3 temperature-programmed desorption (NH3-TPD). The results reveal that the tungsten loadings were crucial to the dispersion and reducibility of the tungsten oxide species and the acidity of catalysts. The catalytic performances were also investigated during the metathesis of 1-butene to propene. Amongst these catalysts, W/SiO2/Al2O3 with a tungsten mass fraction of 6.0%gave the highest activity and stability during the 1-butene metathesis reaction. The excel ent catalytic performance of the catalyst containing a tungsten mass fraction of 6.0%is attributed to its moderate dispersion, suitable reducibility of the WOx species and suitable acidity. We speculate that these factors are favorable for the formation of active centers for olefin metathesis.%采用浸渍法制备了一系列钨负载量不同的W/SiO2/Al2O3催化剂.采用X射线衍射(XRD)、激光拉曼(Raman)光谱、紫外-可见(UV-Vis)光谱、氢气程序升温还原(H2-TPR)和氨程序升温脱附(NH3-TPD)等技术对催化剂进行了表征.实验结果表明:钨的负载量对催化剂上氧化钨物种的分散程度、还原性以及催化剂的酸性有非常重要的影响.对该类催化剂上1-丁烯自歧化反应进行了详细考察,结果表明:当钨的质量分数为6.0%时, W/SiO2/Al2O3催化剂表现出最佳的歧化活性和稳定性.原因在于6.0%的钨负载量可以使催化剂上氧化钨物种具有中等程度的分散性、合适的还原性,并且使催化剂具有一定程度的酸性,这些因素有利于在催化剂上形成烯烃歧化活性位.

  6. 偏心射流搅拌强化1,3-二氯-2-丁烯的氯化行为%Process intensification of 1,3-dichloro-2-butene chlorination with eccentric jetted-stirred tank

    Institute of Scientific and Technical Information of China (English)

    刘作华; 冉启诚; 宁伟征; 孙大贵; 陶长元; 刘仁龙; 牟天明

    2012-01-01

    1,3-氯-2-丁烯(DCB)的氯化过程同时存在加成反应、取代反应和连续反应,DCB与氯气混合不均匀和反应热移除效果不佳会降低取代氯化的选择性.搅拌槽内流场分布特征与流体的混合效果、化学反应的转化率和选择性等密切相关,调控流场结构有助于强化DCB的氯化行为.文中结合搅拌器专用计算流体动力学软件MixSim 2.0.2,模拟了在偏心射流条件下4 cm二直叶桨式搅拌器4cm斜叶圆盘搅拌器和5 cm斜叶圆盘搅拌器槽内的流场分布特征,并进行了DCB氯化实验.研究表明:偏心射流能改变流场分布,控制流场的拟序结构,强化混合效果.在偏心斜射流的条件下,5 cm斜叶圆盘搅拌器的氯化效果较优,能够使DCB氯化的主产物2,3,4-三氯-1-丁烯(TCB)的收率提高到87.9%.%Addition reaction, substitution reaction and continuous reaction occur simultaneously in the chlorination of 1,3-dichloro-2-butene (DCB). The undermixing of DCB and chlorine, and inefficient dissipation of reaction heat can lead to a low selectivity of substitution production. The features of flow field in stirred tank are closely related to the mixing performance, the conversion and selectivity of chemical reaction, and so on. The control of flow field structure is vital to intensify the process of DCB chlorination. A special CFD software MixSim 2.0. 2 for agitator was employed to study the mixing power and flow field of chlorine and DCB with chlorine eccentric jet in a tank stirred by 4 cm two-straight bladed paddle, 5 cm and 4 cm pitched paddle disc agitator, respectively. The experimental results show that flow field structure and coherent structure can be controlled by the eccentric jet, the mixing performance can be enhanced, and the chlorination performance stirred by 5 cm pithed paddle disc agitator was better than that of others' with the eccentric jet, and its yield of goal product 2,3,4-trichloro-l-butene (TCB) is increased to 87.9%.

  7. Valorisation de la coupe C4 de vapocraquage via l'hydrogénation du butadiène, l'isomérisation des butènes et la métathèse, en MTBE ou en propylène Upgrading the C4 Cut from Steam Cracking via the Hydrogenation of Butadiene, the Isomerization of Butenes and Metathesis Into Mtbe Or Propylene

    Directory of Open Access Journals (Sweden)

    Chaumette S.

    2006-11-01

    of the cut can be transformed into MTBE by implementing the new n-butene isomerization process. Another upgrading scheme consits in transforming isobutene into MTBE and n-butenes into propylene by metathesis with ethylene. These new route may find competition in the transformation of butenes into alkylates, for automotive gasoline, with or without MTBE production. After a brief review of the different markets for the products involved, a technico-economic study serves to classify the different upgrading routes of the C4 cut from steam cracking, by comparing both the minimum profitable selling prices for a discounting rate of 12% and the discounted cash-flow rate of return for fixed selling prices. Calculations are performed within a context in which the C4 cut is devalorized in relation to naphtha with a price of $152/t. When butadiene no longer finds any outlets, and when its price is at a very low level such as $270/t, its extraction is hardly profitable, and propylene production by methatesis proves to be more advantageous. However, if the steam cracker is integrated in a refinery, butenes may also be advantageously transformed into alkylates or MTBE, more especially to meet a demand for octane or oxygenated products for fuels. These different routes for upgrading MTBE are more advantageous than MTBE production from butanes, requiring heavy investments for the separation of butanes, the isomerization of n-butane and the dehydrogenation of isobutane. Likewise, the transformation of butenes into propylene is more profitable than obtaining propylene by the dehydrogenation of proprane. A sensitivity study, for the price of butadiene and also for the price of other products, enables isoprofitability curves to be plotted, which delimite price zones favorable to one or the other of the products considered, taken two by two.

  8. Solubility parameter of poly[styrene-b-(1-butene-co-ethylene)-b-styrene

    Science.gov (United States)

    Wohlfarth, Ch.

    This document is part of Subvolume D2 'Polymer Solutions - Physical Properties and their Relations I (Thermodynamic Properties: PVT -Data and miscellaneous Properties of polymer Solutions) of Volume 6 `Polymers' of Landolt-Börnstein - Group VIII `Advanced Materials and Technologies'.

  9. KINETIC ANALYSIS OF ISOBUTENE/BUTENE ALKYLATION OVER ULTRASTABLE H-Y ZEOLITE. (R824729)

    Science.gov (United States)

    The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Concl...

  10. Tref and crystaf analyses of an ethylene-1-butene copolymer synthesized with a heterogeneous Ziegler-Natta catalyst

    International Nuclear Information System (INIS)

    The distributions of molecular weight and chemical composition of a linear low-density polyethylene resin synthesized with a Ziegler-Nata (ZN) catalyst and its fractions were analysed with preparative temperature rising elution fractionation (P-TREF), crystallization analysis fractionation (CRYSTAF), high-temperature gel permeation chromatography. Differential scanning calorimetry, 13 C nuclear magnetic resonance (13 C-NMR). Fourier transform infrared and gradient density column were used to obtain the structural properties of the samples. These results were to correlate the multiplicity of active species on the catalyst to the chemical and molecular weight distributions. It will be shown that these fractionation techniques can be powerful tools to understand the behaviour of ZN-type catalysts and the structural properties of the produced resins. (author)

  11. Metallo-Phosphorylation of Alkynes: Reaction of Alkynes with Cp2Zr(1-butene) ( PR3 ) and Chlorophosphate

    Institute of Scientific and Technical Information of China (English)

    XI Chan-Juan; LAI Chun-Bo; CHEN Chao; HONG Xiao-Yin

    2003-01-01

    @@ Phosphorylation of alkynes is an attractive reaction for the synthesis of stereodefined alkenylphosphonates that are useful intermediates in organic synthesis. Particularly interesting and challenging reactions are those involving the region- and stereo-selective simultaneous introductions of phosphate and other functional groups to multiple carbon-carbon bonds.[1,2

  12. Fluid phase equilibria of the reaction mixture during the selective hydrogenation of 2-butenal in dense carbon dioxide

    DEFF Research Database (Denmark)

    Musko, Nikolai; Jensen, Anker Degn; Baiker, Alfons;

    2012-01-01

    performed using a 5wt% Pd on activated carbon in custom-designed high pressure autoclaves at 323K. The Cubic-Plus-Association (CPA) equation of state was employed to model the phase behaviour of the experimentally studied systems. CPA binary interaction parameters were estimated based on the experimental...

  13. Grubbs's Cross Metathesis of Eugenol with cis-2-butene-1, 4-diol to Make a Natural Product: An Organometallic Experiment for the Undergraduate Lab

    Science.gov (United States)

    Taber, Douglass F.; Frankowski, Kevin J.

    2006-01-01

    A modified experimental procedure for the one-step synthesis that is suitable for the undergraduate organic lab is presented. In the course of work towards the more routine use of air-sensitive organometallic complexes such as the Grubb's catalyst, the natural product (E)-4-(4-hydroxy-3-methoxyphenyl) but-2-en-ol, 4, was synthesized.

  14. Partial oxidation of Raffinate II and other mixtures of n-Butane and n-Butenes to maleic anhydride in a fixed-bed reactor

    OpenAIRE

    Brandstädter, Willi Michael

    2008-01-01

    The utilisation of the C4 streams of steamcrackers by converting raffinate II to maleic anhydride was studied. The oxidation reactions were investigated in a laboratory-scale fixed-bed reactor to determine reaction kinetics. The effects of pore diffusional resistance were investigated and explained. A two-dimensional pseudo-homogeneous reactor model was used for the simulation of a production-scale fixed-bed reactor. A flow scheme of the reactor section including a recycle was proposed.

  15. Dynamic Simulation of Butene Isomerization by Reactive Distillation%丁烯异构反应精馏过程动态模拟

    Institute of Scientific and Technical Information of China (English)

    胡展

    2009-01-01

    建立了以严格的相平衡计算为基础的2-丁烯反应精馏制1-丁烯反应精馏塔的动态机理模型.用RKS方法和Scatchard-Hildebrand方程计算体系的逸度和活度,用可变阶数的NDFs方法求解全塔的组分物料衡算方程.结果表明,所建立的模型能很好的反映反应精馏开车过程的动态特性.

  16. 萃取精馏分离丁烷/丁烯%Selection of solvents for separating butane and butene by extractive distillation

    Institute of Scientific and Technical Information of China (English)

    雷志刚; 许峥; 周晓颖; 廖波; 易波

    2000-01-01

    介绍了两种分离丁烷/丁烯的方法,即乙腈(ACN)法和二甲基甲酰胺 (DMF) 法.对两种工艺流程进行了计算对比,DMF 法工艺流程比ACN 法简单,只需3个塔.计算结果表明,DMF法再沸器和冷凝器能耗分别比ACN法降低33.7%和22.7%,选择DMF法萃取精馏分离丁烷/丁烯效果较好.

  17. n-Butane catalytic dehydrogenation to butene on VOX/SiO2 catalysts%VOx/SiO2催化剂上正丁烷催化脱氢制正丁烯

    Institute of Scientific and Technical Information of China (English)

    胥月兵; 陆江银; 钟梅; 王吉德

    2008-01-01

    在微型固定床反应器上考察了催化剂的焙烧温度、钒氧化物负载量、反应温度、H2/n-C4H10比及空速对负载法制备的VOX/SiO2催化剂上正丁烷催化脱氢制正丁烯的反应性能的影响.结果表明:V205负载量为12%(质量分数)、焙烧温度为550℃为最佳催化剂制备条件,反应温度在590~600℃,氢烃摩尔比为1~2及空速在(2~4)×103ml(h·g)范围可获得最佳正丁烯收率30.6%;正丁烯中1.丁烯及2.丁烯产物分布受反应温度影响较大,而几乎不受氢烃比和空速的影响.

  18. Melt-Grafting of Maleic Anhydride onto Poly(1-Butene) with DCP as Initiator%DCP引发高全同聚丁烯-1熔融接枝马来酸酐

    Institute of Scientific and Technical Information of China (English)

    马玉杰; 赵永仙; 姚薇; 黄宝琛

    2010-01-01

    研究了在双螺杆挤出机中,苯乙烯(St)存在下马来酸酐(MAH)熔融接枝高全同聚丁烯-1(iPB-1)的过程.分别考察了温度、MAH和St用量对接枝率和熔体流动速率(MFIR)的影响.结果表明,双螺杆挤出机反应区的适宜温度为170℃,在此温度下.MAH含量到5%时,接枝率达到最大;MAH含量一定时,MAH:St=1:1时两种单体可以较好地相互作用,并在引发剂的作用下优先生成苯乙烯与马来酸酐的共聚物(SMA),然后再与iPB-1大分子链自由基或链端自由基发生反应,生成接枝物,此时接枝率达到最大.

  19. Dynamic Model and Start-Up Simulation of Isomerization of Butene by Reactive Distillation%丁烯异构反应精馏动态模型和开车过程模拟

    Institute of Scientific and Technical Information of China (English)

    胡展; 周兴贵; 钟思青; 谢在库

    2009-01-01

    建立了以严格的相平衡计算为基础的2-丁烯反应精馏制1-丁烯的过程动态模型,其中各组分的逸度和活度用RKS方法和Scatchard-Hildebrand方程计算.在模拟计算时用差分方法求解塔板的能量衡算方程,用可变阶数Numerical Differentiation Formulas(NDFs)方法求解全塔的组分物料衡算方程.比较了开车时不同的阀门线性调节时间对过程变量的影响.结果表明,所建立的模型能很好地反映反应精馏过程的动态特性,开车时可先进行全回流操作,之后直接将进出料阀门瞬间开至设定值.

  20. A Large Scale Formal Synthesis of CoQ{sub 10}: Highly Stereoselective Friedel-Crafts Allylation Reaction of Tetramethoxytoluene with (E)-4-Chloro-2-methyl-1-phenylsulfonyl-2-butene in the Presence of Montmorillonite K-10

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang Who; Lee, Hee Bong; Kim, Bong Chan; Sadaiah, Kadivendi; Lee, Kyuwoong; Shin, Hyunik [LG Life Sciences, Ltd., Daejeon (Korea, Republic of)

    2013-04-15

    We disclosed that MK-10 is a highly effective catalyst for the Friedel-Crafts reaction of 6 and 7 in terms of yield and of stereoselectivity. Although there are numerous applications of clays in Friedel-Crafts reaction, there is very limited example which demonstrated its effect on the stereoselectivity. In that context, our result is significant and further expansion in this direction is highly envisioned. Ubiquinone, as its name represents, exists ubiquitously in human body, particularly in the heart. It mediates the electron transfer process in mitochondria and also exerts strong antioxidant effect in its reduced form. In clinical trial, it showed beneficial effect on heart-related diseases such as myocardial infarction, angina, and other related symptoms to cause decreased mortality compared to the placebo group.

  1. Dehydrogenation of n-butane over vanadia catalysts supported on silica gel

    Institute of Scientific and Technical Information of China (English)

    Yuebing Xu; Jiangyin Lu; Mei Zhong; Jide Wang

    2009-01-01

    VOx/SiO2 catalysts prepared by impregnation method were used for catalytic dehydrogenation of n-butane to butenes and characterized by X-ray diffraction,FT-IR,UV-vis,Raman,and BET measurements.The effects of VOx loading and the reaction temperature on the VOx/SiO2 catalysts and their catalytic performances for the dehydrogenation of n-butane were studied.When the VOx loading was 12% g/gcat and reaction temperature was between 590 ℃ and 600 ℃,n-butane conversion and butenes yields reached the highest value under H2 flux of 10 ml/min and n-butane flux of 10 ml/min.Product distribution,such as the ratio of 2-butene to 1-butene and the ratio of cis-2-butene to trans-2-butene,was mainly influenced by the reaction temperature.

  2. Antimicrobial activity of cationic gemini surfactant containing an oxycarbonyl group in the lipophilic portion against gram-positive and gram-negative microorganisms.

    Science.gov (United States)

    Tatsumi, Taiga; Imai, Yoshitane; Kawaguchi, Kakuhiro; Miyano, Naoko; Ikeda, Isao

    2014-01-01

    We evaluated the antimicrobial activities of a cationic Gemini surfactant, trans-1,4-bis[2-(alkanoyloxy)ethyldimethylammonio]-2-butene dichloride [II-m-2(t-butene)] and its derivatives against Gram-positive and Gram-negative microorganisms. The II-m-2(t-butene) compound was previously shown to have good surface activity and biodegradability. A dodecanoyloxy derivative (m = 12) of II-m-2(t-butene) showed excellent antimicrobial activity against Gram-positive Streptococcus aureus [minimum inhibitory concentration (MIC): 7.8 μg/mL] and Gram-negative Escherichia coli (MIC: 31.2 μg/mL). PMID:24420061

  3. Conjugation of isoprene monoepoxides with glutathione, catalyzed by α, μ, π and θ-class glutathione S-transferases of rat and man

    NARCIS (Netherlands)

    Bogaards, J.J.P.; Venekamp, J.C.; Salmon, F.G.C.; Bladeren, P.J. van

    1999-01-01

    In the present study, the enzymatic conjugation of the isoprene monoepoxides 3,4 epoxy-3-methyl-1-butene (EPOX-I) and 3,4-epoxy-2-methyl-1-butene (EPOX-II) with glutathione was investigated, using purified glutathione S-transferases (GSTs) of the α, μ, π and θ-class of rat and man. HPLC analysis of

  4. Microwave-Assisted Synthesis of a Natural Insecticide on Basic Montmorillonite K10 Clay. Green Chemistry in the Undergraduate Organic Laboratory

    Science.gov (United States)

    Dintzner, Matthew R.; Wucka, Paul R.; Lyons, Thomas W.

    2006-01-01

    A detailed investigation of the clay-catalyzed condensation of sesamol and other phenols with 3-methyl-2-butenal to give methylenedioxyprecocene (MDP) and other chromenes is presented. The clay-catalyzed microwave-assisted condensation of sesamol with 3-methyl-2-butenal is appropriate for incorporation into undergraduate organic laboratory…

  5. Insights into the deactivation mechanism of supported tungsten hydride on alumina (W-H/Al2O3) catalyst for the direct conversion of ethylene to propylene

    KAUST Repository

    Mazoyer, Etienne

    2014-04-01

    Tungsten hydride supported on alumina prepared by the surface organometallic chemistry method is an active precursor for the direct conversion of ethylene to propylene at low temperature and pressure. An extensive contact time study revealed that the dimerization of ethylene to 1-butene is the primary and also the rate limiting step. The catalytic cycle further involves isomerization of 1-butene to 2-butene, followed by cross-metathesis of ethylene and 2-butene to yield propylene with high selectivity. The deactivation mechanism of this reaction has been investigated. The used catalyst was extensively examined by DRIFTS, solid-state NMR, EPR, UV-Vis, TGA and DSC techniques. It was found that a large amount of carbonaceous species, which were due to side reaction like olefin polymerization took place with time on stream, significantly hindering the dimerization of ethylene to 1-butene and therefore the production of propylene. Crown Copyright © 2014 Published by Elsevier B.V. All rights reserved.

  6. Studies on reactions of cerium(4) reduction with alcohols. Part 3. Reactions of cerium(4) reduction with butane-2,3-diol, butane-1,3-diol and cis-butene-2-diol-1,4 in aqueous solutions of perchloric acid

    International Nuclear Information System (INIS)

    The basic study of the red-ox reaction kinetics of cerium ions -diols-water systems in presence of the perchloric acid is given. Dependence of the various agents and its concentrations on equilibrium constants the complex formation reactions and complex stability are discussed and compared. (B.Cz.)

  7. 吲哚基丁烯酮缩氨基硫脲配合物的合成及生物活性%Synthesis and biological activities of transition metal complexes with the schiff base ligand indolyi substituted 3-buten-2-one thiosemicarbazone

    Institute of Scientific and Technical Information of China (English)

    孙纲春; 曲建强; 王流芳; 陈耐生; 陈晓光; 李燕; 谢晶曦

    2006-01-01

    缩氨基硫脲类Schiff碱化合物因具有显著的抗菌和抗肿瘤等活性而受到广泛关注,研究发现很多这类化合物与金属离子形成配合物以后,生物活性明显增强。例如,3-乙氧基-2-氧代丁醛双缩氨基硫脲(H2KTs)单独用于治疗大鼠腹水癌瘤没有效果,而H2KTs与铜的配合物则可明显抑制大鼠腹水癌瘤。由于研究这类化合物有重要意义,考虑到吲哚类化合物往往出具有多种生物活性,我们利用拼合原理设计合成了一种带有吲哚基团的缩氨基硫脲Schiff碱配体,并制备了其铜、镍、锌、钴四种边渡金属的配合物,并对配体和配合物的抗菌、抗种瘤活性进行了测试。

  8. 水蒸气处理对ZSM-5酸性及其催化丁烯裂解性能的影响%Effects of Steam Treatment on Acidity of ZSM-5 and Its Catalytic Performance in Butene Cracking

    Institute of Scientific and Technical Information of China (English)

    朱向学; 张士博; 钱新华; 牛雄雷; 宋月芹; 刘盛林; 徐龙伢

    2004-01-01

    考察了水蒸气处理温度和时间对ZSM-5分子筛酸性及其催化丁烯裂解性能的影响.结果表明,通过水蒸气处理可降低ZSM-5分子筛的酸量和酸强度,明显提高产物中丙烯与乙烯的选择性和收率,抑制副产物芳烃和低碳烷烃的生成.用柠檬酸脱除水蒸气处理过程中产生的非骨架铝,可提高ZSM-5分子筛孔道的容碳能力,从而提高催化剂的稳定性.考察了反应条件对催化剂性能的影响,结果表明较佳的反应条件为WHSV=3.5~8.8 h-1,p=0.06~0.1 MPa,θ=600~620 ℃.

  9. Synthesis and E/Z Configuration Determination of Novel Derivatives of 3-Aryl-2-(benzothiazol-2'-ylthio Acrylonitrile, 3-(Benzothiazol-2'-ylthio-4-(furan-2''-yl-3-buten-2-one and 2-(1-(Furan-2''-yl-3'-oxobut-1''-en-2-ylthio-3-phenylquinazolin-4(3H-one

    Directory of Open Access Journals (Sweden)

    Adel Abou El-Khair

    2011-07-01

    Full Text Available Knoevenagel condensation of 2-(benzothiazol-2-ylthio acetonitrile (2 with either furan-2-carbaldehyde or thiophene-2-carbaldehydes leads to E-isomers 4a–b exclusively, while the condensation of the compound 2 with benzaldehyde or para-substituted benzaldehydes with an electron-donating group afforded E/Z mixtures 4c–e with preferentially formation of the E-isomer. Condensation of furan-2-carbaldehyde (3a with either 1-(benzothiazol-2'-ylthio propan-2-one (5 or 2-(2'-oxo propylthio-3-phenyl-quinazolin-4(3H-one (9 leads exclusively to the Z-isomers of 6 and 10, respectively. The structures of the newly synthesized compounds were elucidated by elemental analyses, 1H-NMR and 13C-NMR spectra, COSY, HSQC, HMBC, NOE, MS and X-ray crystallographic investigations.

  10. Vacuum ultraviolet photochemistry of tetrahydrothiophene and sulfolane

    International Nuclear Information System (INIS)

    The vacuum uv photolysis of tetrahydrothiophene (THT) involves the breaking of the S to α-C bond. Besides ethylene, C3H6 and 1,3-butadiene are also formed. Photolyses of THT, tetrahydrofuran, and pyrrolidine are similar. The vacuum uv photolysis of tetramethylene sulfone (sulfolane) was also studied; products are SO2, cyclobutane, 1-butene, and ethylene. No cis-2-butene was observed

  11. 煤制烯烃混合碳四的利用探讨%The Utilization of Coal-based Mixed C4

    Institute of Scientific and Technical Information of China (English)

    姜涛; 兰秀菊

    2011-01-01

    煤制烯烃的重要副产品是混合碳四.通过对煤基混合碳四中主要成分丁烯-1和丁烯-2的用途讨论,综述了利用其生产石油树脂、乙烯、丙烯、丁烯-1、己烯-1、甲乙酮、聚丁烯-1,2-丙基庚醇等不同反应途径的工艺流程、反应原理及工业化进程.得出其最有前途的利用方向是生产丁烯-1、己烯-1、聚丁烯-1、2-丙基庚醇.%The utilization of 1-Butene and 2-Butene which are the major components of the coal-based mixed C4′s was discussed in this paper. Some conclusions were reached, i.e. they can be used to produce resin, ethylene, propylene,1-Butene, 1-hexylene, methyl-ethyl ketone, poly( 1-butene)resin or 2-propyheptanol products. Especially ,they are used to produce 1-Butene, 1-hexylene, poly( 1-butene)resin or 2-propyheptanol products.

  12. Selective hydrogenation of 1,3-butadiene from crude C{sub 4} cracker stream with a solid catalyst with ionic liquid layer (SCILL). DSC and solubility study

    Energy Technology Data Exchange (ETDEWEB)

    Mangartz, T.; Korth, W.; Kern, C.; Jess, A. [Bayreuth Univ. (Germany). Dept. of Chemical Engineering

    2013-11-01

    In petroleum as well as in fine chemical industry, selective catalytic hydrogenation is an important reaction. The selective hydrogenation of 1,3-butadiene (BD) to butene (trans-,1- and cis-butene) from the crude C4 steam cracker fraction represents one example, but under today's technical conditions undesired butane forms inevitably in relevant amounts. To increase the butene yield, the concept of Solid Catalyst with Ionic Liquid Layer (SCILL) was employed. The SCILL catalyst, in contrast to the uncoated catalyst, yielded a remarkably high selectivity to butenes (S{sub butenes} > 99 %) even at high residence times or at high hydrogen partial pressure. Nearly no butane (S{sub butane} {approx} 0 %) was analytically detected. We expected that due to different solubility, the poorer soluble compounds discharged from the ionic liquid and, thus, caused the shift in selectivity to a great extent. Temperature dependent solubility measurements in the used ionic liquid ([DMIM][DMP]) revealed that the order of increasing solubility is 1,3-butadiene > butenes > butane which matches the assumption. However, since differences in solubility cannot explain this SCILL effect satisfyingly, ionic liquids are expected to affect the surface of the catalyst (side-specific ligand-type effect). Investigations using spectroscopic methods (e.g. FTIR) confirmed this suggestion. (orig.)

  13. Metabolic engineering for the high-yield production of isoprenoid-based C5 alcohols in E. coli

    Science.gov (United States)

    George, Kevin W.; Thompson, Mitchell G.; Kang, Aram; Baidoo, Edward; Wang, George; Chan, Leanne Jade G.; Adams, Paul D.; Petzold, Christopher J.; Keasling, Jay D.; Soon Lee, Taek

    2015-06-01

    Branched five carbon (C5) alcohols are attractive targets for microbial production due to their desirable fuel properties and importance as platform chemicals. In this study, we engineered a heterologous isoprenoid pathway in E. coli for the high-yield production of 3-methyl-3-buten-1-ol, 3-methyl-2-buten-1-ol, and 3-methyl-1-butanol, three C5 alcohols that serve as potential biofuels. We first constructed a pathway for 3-methyl-3-buten-1-ol, where metabolite profiling identified NudB, a promiscuous phosphatase, as a likely pathway bottleneck. We achieved a 60% increase in the yield of 3-methyl-3-buten-1-ol by engineering the Shine-Dalgarno sequence of nudB, which increased protein levels by 9-fold and reduced isopentenyl diphosphate (IPP) accumulation by 4-fold. To further optimize the pathway, we adjusted mevalonate kinase (MK) expression and investigated MK enzymes from alternative microbes such as Methanosarcina mazei. Next, we expressed a fusion protein of IPP isomerase and the phosphatase (Idi1~NudB) along with a reductase (NemA) to diversify production to 3-methyl-2-buten-1-ol and 3-methyl-1-butanol. Finally, we used an oleyl alcohol overlay to improve alcohol recovery, achieving final titers of 2.23 g/L of 3-methyl-3-buten-1-ol (~70% of pathway-dependent theoretical yield), 150 mg/L of 3-methyl-2-buten-1-ol, and 300 mg/L of 3-methyl-1-butanol.

  14. Catalytic Dehydrogenation of n-Butane over V/SiO2 Catalyst: A Comparison with Cr/SiO2 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Xu Yuebing; Fu Wenting; Lu Jiangyin; Wang Jide

    2008-01-01

    V/SiO2 catalysts compared to Cr/SiO2 catalysts were studied for dehydrogenation of n-butane to butenes.Several methods for characterization of catalysts such as FT-IR,UV-vis and Raman spectroscopies were used.Some differences between two catalysts were showed,including the performances of catalysts,distribution of products and mechanism of reactions.The results showed that prepared catalysts with 12m% of active component loading all demonstrated best conversion of n-butane to butene at a reaction temperature of around 590℃.Two different reaction mechanisms were mentioned to well explain why iso-butene was produced on V/SiO2 catalysts but not on Cr/SiO2 catalysts.

  15. Structure Sensitivity in Pt Nanoparticle Catalysts for Hydrogenation of 1,3-Butadiene: In Situ Study of Reaction Intermediates Using SFG Vibrational Spectroscopy

    KAUST Repository

    Michalak, William D.

    2013-01-31

    The product selectivity during 1,3-butadiene hydrogenation on monodisperse, colloidally synthesized, Pt nanoparticles was studied under reaction conditions with kinetic measurements and in situ sum frequency generation (SFG) vibrational spectroscopy. SFG was performed with the capping ligands intact in order to maintain nanoparticle size by reduced sintering. Four products are formed at 75 C: 1-butene, cis-2-butene, trans-2-butene, and n-butane. Ensembles of Pt nanoparticles with average diameters of 0.9 and 1.8 nm exhibit a ∼30% and ∼20% increase in the full hydrogenation products, respectively, as compared to Pt nanoparticles with average diameters of 4.6 and 6.7 nm. Methyl and methylene vibrational stretches of reaction intermediates observed under working conditions using SFG were used to correlate the stable reaction intermediates with the product distribution. Kinetic and SFG results correlate with previous DFT predictions for two parallel reaction pathways of 1,3-butadiene hydrogenation. Hydrogenation of 1,3-butadiene can initiate with H-addition at internal or terminal carbons leading to the formation of 1-buten-4-yl radical (metallocycle) and 2-buten-1-yl radical intermediates, respectively. Small (0.9 and 1.8 nm) nanoparticles exhibited vibrational resonances originating from both intermediates, while the large (4.6 and 6.7 nm) particles exhibited vibrational resonances originating predominately from the 2-buten-1-yl radical. This suggests each reaction pathway competes for partial and full hydrogenation and the nanoparticle size affects the kinetic preference for the two pathways. The reaction pathway through the metallocycle intermediate on the small nanoparticles is likely due to the presence of low-coordinated sites. © 2012 American Chemical Society.

  16. Identification of Halohydrins as Potential Disinfection By-Products in Treated Drinking Water

    Directory of Open Access Journals (Sweden)

    Karl J. Jobst

    2011-01-01

    It appears that DBP-A is 3-chloro-2-methylbutan-2-ol and that DBP-B is its bromo analogue. DBP-B has been detected in ozonated waters containing bromide. Our study also shows that these DBPs can be laboratory artefacts, generated by the reaction of residual chlorine in the sample with 2-methyl-2-butene, the stabilizer in the CH2Cl2 used for extraction. This was shown by experiments using CH2Cl2 stabilized with deuterium labelled 2-methyl-2-butene. Quenching any residual chlorine in the drinking water sample with sodium thiosulfate minimizes the formation of these artefacts.

  17. Debaryomyces hansenii strains differ in their production of flavor compounds in a cheese-surface model

    DEFF Research Database (Denmark)

    Gori, Klaus; Sørensen, Louise Marie; Petersen, Mikael Agerlin;

    2012-01-01

    important cheese flavor compounds, primarily branched-chain aldehydes and alcohols, and thus important for the final cheese flavor. Quantification of representative aldehydes (2-Methylpropanal, 3-Methylbutanal) and alcohols (2-Methyl-1-propanol, 3-Methyl-1-butanol, and 3-Methyl-3-buten-1-ol) showed...... that the investigated D. hansenii strains varied significantly with respect to production of these flavor compounds. Contrary to the alcohols (2-Methyl-1-propanol,3-Methyl-1-butanol, and3-Methyl-3-buten-1-ol), the aldehydes (2-Methylpropanal, 3-Methylbutanal) were produced by the D. hansenii strains in concentrations...

  18. Research in chemical kinetics. Progress report, August 1, 1987--July 20, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Rowland, F.S.

    1996-09-01

    This paper describes chemical kinetics research in the following areas: reactions of thermalized tritium atoms with organo-tin compounds; studies on the hydrolysis of OCS and CS{sub 2}; thermal chlorine 38 reactions with 2,3-dichloro-hexafluoro-2-butene; and thermal T reactions with fluoroethylenes.

  19. Gas-phase chemistry of the yttrium-imido cation YNH{sup +} with alkenes: {Beta}-hydrogen activation by a d{sup 0} system via a multicentered transition state

    Energy Technology Data Exchange (ETDEWEB)

    Ranatunga, D.R.A.; Hill, Y.D.; Freiser, B.S. [Purdue Univ., West Lafayette, IN (United States)

    1996-02-20

    The gas-phase chemistry of the yttrium-imido carbon cations with alkenes was studied by using Fourier transform mass spectrometry to explore the chemistry of transition metal ion complexes with low-valence metal centers. The YNH{sup +} species was synthesized by reacting Y{sup +}, generated by laser desorption, with ammonia. The dehydrogenation reaction is exothermic, yielding a lower limit for the imido bond energy of D{degree}(Y{sup +}-NH) > 101 kcal/mol. Due to the electron deficiency of the metal center upon binding to NH, the further reactivity of YNH{sup +} can only be explained by a reaction mechanism involving a multicentered transition state. YNH{sup +} reacts with ethene predominantly by dehydrogenation to produce YC{sub 2}H{sub 3}N{sup +}. Thus, instead of the metathesis reaction involving the cleavage of the 2-aza-1-metallacyclobutane intermediate, a {beta}-hydrogen transfers to the metal center and is then eliminated with a hydrogen from the remaining CH{sub 2} group to complete the reaction. All three linear butenes, 1-butene, cis-2-butene, and trans-2-butene, react very similarly with YNH{sup +}, yielding a variety of product ions with the predominant loss of NH{sub 3} resulting in the formation of YCH{sub 4}H{sub 6}{sup +}. Structural studies on this ion suggest that it is bent metallacyclopent-3-ene, not the butadiene isomer. 34 refs., 1 fig.

  20. CATALYTIC AND ADSORPTION PROPERTIES OF Al- AND Ti-MCM-41 SYNTHESIZED AT ROOM TEMPERATURE

    OpenAIRE

    Silva, Tiago N.; Lopes, José Madeira; Ribeiro, Fernando Ramôa; Carrott, Manuela Ribeiro; Galacho, Cristina; Sousa, Maria José; Carrott, Peter

    2002-01-01

    Aluminosilicate and titanosilicate MCM-41 were synthesized using a room temperature method. A preliminary catalytic evaluation was performed in the promotion of the 1-butene double bond isomerization, which was successful in probing differences in the acidity of the samples prepared.

  1. Industrial processes of olefin metathesis. Pt. 1

    Energy Technology Data Exchange (ETDEWEB)

    Warwel, S.

    1987-05-01

    Olefin metathesis opens new synthetic routes to typical petrochemicals (ethylene, propylene, n-butenes), special olefins (neohexene, higher molecular linear olefins, , -dienes) and unsaturated polymers (polynorbornene, -cyclooctene, -dicyclopentadiene) in an industrial scale. The 8 metathesis processes used in industry and further possible applications of olefin metathesis are reviewed.

  2. RUTHENIUM-CATALYZED TANDEM OLEFIN MIGRATION-ALDOL AND MANNICH-TYPE REACTIONS IN IONIC LIQUID.

    Science.gov (United States)

    In the presence of a catalytic amount of RuCl2(PPh3)3, a cross-coupling of 3-buten-2-ol with aldehydes and imines was developed via a tandem olefin migration--aldol--Mannich reaction in bmim[PF6]. With In(OAc)3 as a co-catalyst, a-vinylbenzyl alcohol and aldehydes underwent sim...

  3. Determination of Tamoxifen and its Major Metabolites in Exposed Fish

    Science.gov (United States)

    Tamoxifen (TAM), (Z)-1-(p-dimethylaminoethoxyphenyl)-1, 2-diphenyl-1-butene, is a nonsteroidal agent that has been used in breast cancer treatment for decades. Its major metabolites are 4-hydroxytamoxifen (4-OHT), N-desmethyltamoxifen (DMT), and endoxifen. While TAM and metabolit...

  4. Plasma polymerization coating of D-T filled glass shells for laser fusion targets

    International Nuclear Information System (INIS)

    Three plasma sources are described which activate monomers of perfluoro-2-butene or tetrafluoroethylene to produce coatings 10 to 20 μm thick with surfaces finishes <0.1 μm. Electrical and chemical controls of the polymerization processes are shown to improve the surface finish

  5. Direct Conversion of n-Butane to Isobutene over Pt–MCM22

    NARCIS (Netherlands)

    Pirngruber, G.D.; Seshan, K.; Lercher, J.A.

    2000-01-01

    MCM22 is a very active and selective catalyst for the skeletal isomerization of butene. At temperatures up to 775 K, Pt–MCM22 gives good results in the dehydroisomerization of n-butane, achieving higher yields of isobutene than does Pt–ZSM5. Most notably, the formation of cracking products is low. A

  6. A Research-Based Undergraduate Organic Laboratory Project: Investigation of a One-Pot, Multicomponent, Environmentally Friendly Prins-Friedel-Crafts-Type Reaction

    Science.gov (United States)

    Dintzner, Matthew R.; Maresh, Justin J.; Kinzie, Charles R.; Arena, Anthony F.; Speltz, Thomas

    2012-01-01

    Students in the undergraduate organic laboratory synthesize tetrahydro-2-(4-nitrophenyl)-4-phenyl-2"H"-pyran via the Montmorillonite K10 clay-catalyzed reaction of p-nitrobenzaldehye with methanol, 3-buten-1-ol, and benzene. The synthesis comprises an environmentally friendly tandem Prins-Friedel-Crafts-type multicomponent reaction (MCR) and sets…

  7. Purification of a glutathione S-transferase and a glutathione conjugate-specific dehydrogenase involved in isoprene metabolism in Rhodococcus sp. strain AD45

    NARCIS (Netherlands)

    Hylckama Vlieg, Johan E.T. van; Kingma, Jaap; Kruizinga, Wim; Janssen, Dick B.

    1999-01-01

    A glutathione S transferase (GST) with activity toward 1,2-eposy-2-methyl-3-butene (isoprene monoxide) and cis-1,2-dichloroepoxyethane was purified from the isoprene-utilizing bacterium Rhodococcus sp. strain AD45, The homodimeric enzyme (two subunits of 27 kDa each) catalyzed the glutathione (GSH)-

  8. Scope and limitations of chiral bis(oxazoline) ligands in the copper-catalysed asymmetric cyclopropanation of trisubstituted alkenes

    DEFF Research Database (Denmark)

    Østergaard, N.; Jensen, Jakob Feldthusen; Tanner, David Ackland

    2001-01-01

    A series of derivatives of 3-methyl-2-buten-1-ol has been used to test the scope and limitations of the copper-catalysed asymmetric cyclopropanation of trisubstituted alkenes by ethyl diazoacetate in the presence of C-2-symmetric bis(oxazoline) ligands. In the best case, a trans/cis ratio of 91...

  9. Sum Frequency Generation Vibrational Spectroscopy of 1,3-Butadiene Hydrogenation on 4 nm Pt@SiO 2 , Pd@SiO 2 , and Rh@SiO 2 Core–Shell Catalysts

    KAUST Repository

    Krier, James M.

    2015-01-14

    © 2014 American Chemical Society. 1,3-Butadiene (1,3-BD) hydrogenation was performed on 4 nm Pt, Pd, and Rh nanoparticles (NPs) encapsulated in SiO2 shells at 20, 60, and 100 °C. The core-shells were grown around polyvinylpyrrolidone (PVP) coated NPs (Stöber encapsulation) prepared by colloidal synthesis. Sum frequency generation (SFG) vibrational spectroscopy was performed to correlate surface intermediates observed in situ with reaction selectivity. It is shown that calcination is effective in removing PVP, and the SFG signal can be generated from the metal surface. Using SFG, it is possible to compare the surface vibrational spectrum of Pt@SiO2 (1,3-BD is hydrogenated through multiple paths and produces butane, 1-butene, and cis/trans-2-butene) to Pd@SiO2 (1,3-BD favors one path and produces 1-butene and cis/trans-2-butene). In contrast to Pt@SiO2 and Pd@SiO2, SFG and kinetic experiments of Rh@SiO2 show a permanent accumulation of organic material.

  10. Regiospecific synthesis of 2-substituted 4-methyl-3,6-dihydro-2h-pyrans

    Energy Technology Data Exchange (ETDEWEB)

    Kazaryan, P.I.; Avakyan, O.V.; Avakyan, S.V.; Gevorkyan, A.A.

    1986-03-01

    The chloroalkylation of 3-halo-2-methyl-1-buten-4-ols was used to synthesize 4,5-dihalo-4-methyl-2-substituted tetrahydropyrans, which were converted regio-specifically to 3,6-dihydropyrans by reaction with magnesium. A similar reaction with zinc dust gave mixtures of 3,6- and 5,6-dihydropyrans.

  11. Contribution of carbonyl photochemistry to aging of atmospheric secondary organic aerosol

    DEFF Research Database (Denmark)

    Mang, Stephen A.; Henricksen, Dana K.; Bateman, Adam P.;

    2008-01-01

    in situ by infrared cavity ring-down spectroscopy. A number of additional gas-phase products of SOA photodegradation were observed by gas chromatography, including methane, ethene, acetaldehyde, acetone, methanol, and I-butene. The absorption spectrum of SOA material collected onto CaF, windows was...

  12. The chemistry of tributyl phosphate at elevated temperatures in the Plutonium Finishing Plant Process Vessels

    Energy Technology Data Exchange (ETDEWEB)

    Barney, G.S.; Cooper, T.D.

    1994-06-01

    Potentially violent chemical reactions of the tributyl phosphate solvent used by the Plutonium Finishing Plant at the Hanford Site were investigated. There is a small probability that a significant quantity of this solvent could be accidental transferred to heated process vessels and react there with nitric acid or plutonium nitrate also present in the solvent extraction process. The results of laboratory studies of the reactions show that exothermic oxidation of tributyl phosphate by either nitric acid or actinide nitrates is slow at temperatures expected in the heated vessels. Less than four percent of the tributyl phosphate will be oxidized in these vented vessels at temperatures between 125{degrees}C and 250{degrees}C because the oxidant will be lost from the vessels by vaporization or decomposition before the tributyl phosphate can be extensively oxidized. The net amounts of heat generated by oxidation with concentrated nitric acid and with thorium nitrate (a stand-in for plutonium nitrate) were determined to be about -150 and -220 joules per gram of tributyl phosphate initially present, respectively. This is not enough heat to cause violent reactions in the vessels. Pyrolysis of the tributyl phosphate occurred in these mixtures at temperatures of 110{degrees}C to 270{degrees}C and produced mainly 1-butene gas, water, and pyrophosphoric acid. Butene gas generation is slow at expected process vessel temperatures, but the rate is faster at higher temperatures. At 252{degrees}C the rate of butene gas generated was 0.33 g butene/min/g of tributyl phosphate present. The measured heat absorbed by the pyrolysis reaction was 228 J/g of tributyl phosphate initially present (or 14.5 kcal/mole of tributyl phosphate). Release of flammable butene gas into process areas where it could ignite appears to be the most serious safety consideration for the Plutonium Finishing Plant.

  13. Preparation and property of two kinds of polyester oxygen scavenger material%两类聚酯吸氧材料的制备及性能

    Institute of Scientific and Technical Information of China (English)

    刘柳; 崔爱军; 何明阳; 陈群; 蔡煜明

    2012-01-01

    制备了1,4-丁烯二醇/顺丁烯二酸酐和端羟基聚丁二烯(HTPB)/顺丁烯二酸酐酯化物吸氧剂,讨论了反应时间及醇酐比对吸氧剂酯化率的影响,并且将1,4-丁烯二醇/顺酐、HTPB/顺酐吸氧剂接枝共聚到PET中得到改性吸氧材料。考察了两种吸氧材料的物理性能和吸氧性能,以及影响吸氧性能的双键保留率,催化剂用量、醇酐比。实验表明,顺酐与1,4-丁烯二醇、HTPB反应的最佳酯化时间分别为2 h和3 h,含1,4-丁烯二醇/顺酐和HTPB/顺酐的吸氧材料最大数均分子量分别为3.66万和4.97万,最大双键保留率分别为77.4%和76.3%,最大催化剂用量为1.0 g/kg,含1,4-丁烯二醇/顺酐和HTPB/顺酐的吸氧材料24 h最大吸氧量为3.17 mL/g和10.04mL/g。%Maleic anhydride/2-butene-1,4-diol and maleic anhydride/terminated polybutadiene oxygen scavenger have been prepared by esterification.The influence of reaction time and ratio of alcohol-anhydride on the esterification rate has been discussed,and maleic anhydride/2-butene-1,4-diol and maleic anhydride/terminated polybutadiene oxygen scavenger have been grafted to PET for preparing oxygen scavenger material.Physical property and oxygen absorption of oxygen scavenger material of 2-butene-1,4-diol and terminated polybutadiene were investigated.Retained ratio of double bonds,catalyst amount,and ratio of alcohol-anhydride were investigated.The results showed the optimal preparation condition of 2-butene-1,4-diol oxygen scavenger reaction time would be 2h under which maleic anhydride esterification rate reached 62.55%,maximum number-average molar mass of 2-butene-1,4-diol oxygen scavenger material reached 36607,retained maximum ratio of double bonds of 2-butene-1,4-diol oxygen scavenger material reached 77.4%,the absorbed oxygen volume of 2-butene-1,4-diol oxygen scavenger material would be 3.17 mL,maximum catalyst amount of 2-butene-1,4-diol oxygen scavenger material and terminated polybutadiene

  14. Isotope effects and the temperature dependences of the hyperfine coupling constants of muoniated sec-butyl radicals in condensed phases.

    Science.gov (United States)

    Fleming, Donald G; Bridges, Michael D; Arseneau, Donald J; Chen, Ya Kun; Wang, Yan Alexander

    2011-04-01

    Reported here is the first μSR study of the muon (A(μ)) and proton (A(p)) β-hyperfine coupling constants (Hfcc) of muoniated sec-butyl radicals, formed by muonium (Mu) addition to 1-butene and to cis- and trans-2-butene. The data are compared with in vacuo spin-unrestricted MP2 and hybrid DFT/B3YLP calculations reported in the previous paper (I), which played an important part in the interpretation of the data. The T-dependences of both the (reduced) muon, A(μ)′(T), and proton, A(p)(T), Hfcc are surprisingly well explained by a simple model, in which the calculated Hfcc from paper I at energy minima of 0 and near ±120° are thermally averaged, assuming an energy dependence given by a basic 2-fold torsional potential. Fitted torsional barriers to A(μ)′(T) from this model are similar (~3 kJ/mol) for all muoniated butyl radicals, suggesting that these are dominated by ZPE effects arising from the C−Mu bond, but for A(p)(T) exhibit wide variations depending on environment. For the cis- and trans-2-butyl radicals formed from 2-butene, A(μ)′(T) exhibits clear discontinuities at bulk butene melting points, evidence for molecular interactions enhancing these muon Hfcc in the environment of the solid state, similar to that found in earlier reports for muoniated tert-butyl. In contrast, for Mu−sec-butyl formed from 1-butene, there is no such discontinuity. The muon hfcc for the trans-2-butyl radical are seemingly very well predicted by B3LYP calculations in the solid phase, but for sec-butyl from 1-butene, showing the absence of further interactions, much better agreement is found with the MP2 calculations across the whole temperature range. Examples of large proton Hfcc near 0 K are also reported, due to eclipsed C−H bonds, in like manner to C−Mu, which then also exhibit clear discontinuities in A(p)(T) at bulk melting points. The data suggest that the good agreement found between theory and experiment from the B3LYP calculations for eclipsed bonds in

  15. Catalytic distillation process

    Science.gov (United States)

    Smith, Jr., Lawrence A.

    1982-01-01

    A method for conducting chemical reactions and fractionation of the reaction mixture comprising feeding reactants to a distillation column reactor into a feed zone and concurrently contacting the reactants with a fixed bed catalytic packing to concurrently carry out the reaction and fractionate the reaction mixture. For example, a method for preparing methyl tertiary butyl ether in high purity from a mixed feed stream of isobutene and normal butene comprising feeding the mixed feed stream to a distillation column reactor into a feed zone at the lower end of a distillation reaction zone, and methanol into the upper end of said distillation reaction zone, which is packed with a properly supported cationic ion exchange resin, contacting the C.sub.4 feed and methanol with the catalytic distillation packing to react methanol and isobutene, and concurrently fractionating the ether from the column below the catalytic zone and removing normal butene overhead above the catalytic zone.

  16. Catalytic conversion of cellulose to liquid hydrocarbon fuels by progressive removal of oxygen to facilitate separation processes and achieve high selectivities

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A.; Ruiz, Juan Carlos Serrano; West, Ryan M.

    2015-06-30

    Described is a method to make liquid chemicals. The method includes deconstructing cellulose to yield a product mixture comprising levulinic acid and formic acid, converting the levulinic acid to .gamma.-valerolactone, and converting the .gamma.-valerolactone to pentanoic acid. Alternatively, the .gamma.-valerolactone can be converted to a mixture of n-butenes. The pentanoic acid can be decarboxylated yield 1-butene or ketonized to yield 5-nonanone. The 5-nonanone can be hydrodeoxygenated to yield nonane, or 5-nonanone can be reduced to yield 5-nonanol. The 5-nonanol can be dehydrated to yield nonene, which can be dimerized to yield a mixture of C.sub.9 and C.sub.18 olefins, which can be hydrogenated to yield a mixture of alkanes.

  17. Excess Molar Volume and Apparent Molar Volume of Binary Mixtures of 2—Methyl—3—buten—2—ol with 1—Alcohol at 298.15K

    Institute of Scientific and Technical Information of China (English)

    LIUDixia; LIHaoran; 等

    2002-01-01

    Excess molar volumes (VmE) of binary mixtures of 2-methyl-3-buten-2-ol[CH3C(OH)(CH3)CHCH2] with four 1-alcohols:methanol,ethanol,1-propanol and 1-butanol at 298.15K and atmospheric pressure are derived from density measurements with a vibrating-tube densimeter.All the excess volumes are negative in the systems over the entire composition range. The results are correlated with the Redlich-Kister equation.The effects of chain length of 1-alcohols on VmE are discussed.The apparent molar volumes of 2-methyl-3-buten-2-ol and 1-alcohols are calculated respectively.

  18. Olefin metathesis reaction on a MoS/sub 2/ catalyst

    Energy Technology Data Exchange (ETDEWEB)

    1976-06-15

    Olefin metathesis reaction was found to take place on rather pure MoS/sub 2/ evacuated at 450/sup 0/C for several hours. Systematic studies of the isotopic scrambling in ethylene, propylene, 1-butene, and 2-butene on MoS/sub 2/ using microwave spectroscopy are reported. These studies were made using /sup 12/C- and /sup 13/C-labelled compounds and D-labelled compounds. Results indicated that the MoS/sub 2/ catalyst evacuated at 450/sup 0/C has two kinds of active sites, one is effective for the isomerization and the hydrogen isotopic mixing of olefins, and the other is effective for the hydrogenation reaction. This may be explained by assuming different degrees of coordinative unsaturation for the active sites. (BLM)

  19. Cladobotryal: a Fungal Metabolite with a Novel Ring System

    DEFF Research Database (Denmark)

    Breinholt, Jens; Jensen, Helle C.; Kjær, Anders;

    1998-01-01

    In screening for antifungal metabolites a novel compound, cladobotryal, was isolated from the mycoparasitic fungus Cladobotryum varium. Its structure was established as (+)-(2R*,3R*)-2-[(Z)- 2-buten-2-yl]-3,7-dihydro-3-formyl-3-methyl-5-phenylfuro[2,3-b]pyr idin-4(2H)-one on the basis of spectros......In screening for antifungal metabolites a novel compound, cladobotryal, was isolated from the mycoparasitic fungus Cladobotryum varium. Its structure was established as (+)-(2R*,3R*)-2-[(Z)- 2-buten-2-yl]-3,7-dihydro-3-formyl-3-methyl-5-phenylfuro[2,3-b]pyr idin-4(2H)-one on the basis...

  20. Hydrothermal Synthesis, Characterization and Catalytic Properties of Nanoporous MoO3/ZrO2 Mixed Oxide

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A nanoporous MoO3/ZrO2 mixed oxide was hydrothermally synthesized by hydrolyzing zirconium isopropoxide in the presence of a cationic surfactant, cetyltrimethylammonium bromide(CTAB). The crystal structure and the acidity of the obtained nanoporous MoO3/ZrO2 mixed oxide were determined by means of XRD, N2 adsorption-desorption and NH3-TPD, respectively. The isobutane/butene alkylation over the MoO3/ZrO2 catalyst was carried out in a fixed bed reactor. The results reveal that ZrO2 in MoO3/ZrO2 exists mainly in the tetragonal phase, and the catalyst samples possess large specific surface areas as well as moderate acidity for isobutane/butene alkylation. Compared with samples prepared by impregnation and sol-gel processes, MoO3/ZrO2 mixed oxide samples prepared in this work have a better catalytic activity.

  1. The synthesis and investigation of impurities found in Clandestine Laboratories: Baeyer-Villiger Route Part I; Synthesis of P2P from benzaldehyde and methyl ethyl ketone.

    Science.gov (United States)

    Doughty, David; Painter, Ben; Pigou, Paul E; Johnston, Martin R

    2016-06-01

    The synthesis of impurities detected in clandestinely manufactured Amphetamine Type Stimulants (ATS) has emerged as more desirable than simple "fingerprint" profiling. We have been investigating the impurities formed when phenyl-2-propanone (P2P) 5, a key ATS precursor, is synthesised in three steps; an aldol condensation of benzaldehyde and methyl ethyl ketone (MEK); a Baeyer-Villiger reaction; and ester hydrolysis. We have identified and selectively synthesised several impurities that may be used as route specific markers for this series of synthetic steps. Specifically these impurities are 3-methyl-4-phenyl-3-buten-2-one 3, 2-methyl-1,5-diphenylpenta-1,4-diene-3-one 9, 2-(methylamino)-3-methyl-4-phenyl-3-butene 16, 2-(Methylamino)-3-methyl-4-phenylbutane 17, and 1-(methylamino)-2-methyl-1,5-diphenylpenta-4-ene-3-one 22. PMID:27081790

  2. The driving force role of ruthenacyclobutanes

    KAUST Repository

    Vummaleti, Sai V. C.

    2015-02-07

    DFT calculations have been used to determine the thermodynamic and kinetic preference for ruthenacyclobutanes resulting from the experimentally proposed interconversion pathways (olefin and alkylidene rotations) through the investigation of cross-metathesis reaction mechanism for neutral Grubbs catalyst, RuCl2(=CHEt)NHC (A), with ethylene and 1-butene as the substrates. Our results show that although the proposed interconversions are feasible due to the predicted low energy barriers (2-6 kcal/mol), the formation of ruthenacyclobutane is kinetically favored over the competitive reactions involving alkylidene rotations. In comparison with catalyst A, the reaction energy profile for cationic Piers catalyst [RuCl2(=CHPCy3)NHC+] (B) is more endothermic in nature with both ethylene and 1-butene substrates.

  3. Catalytic conversion of cellulose to liquid hydrocarbon fuels by progressive removal of oxygen to facilitate separation processes and achieve high selectivities

    Energy Technology Data Exchange (ETDEWEB)

    Dumesic, James A [Verona, WI; Ruiz, Juan Carlos Serrano [Madison, WI; West, Ryan M [Madison, WI

    2014-01-07

    Described is a method to make liquid chemicals. The method includes deconstructing cellulose to yield a product mixture comprising levulinic acid and formic acid, converting the levulinic acid to .gamma.-valerolactone, and converting the .gamma.-valerolactone to pentanoic acid. Alternatively, the .gamma.-valerolactone can be conveted to a mixture of n-butenes. The pentanoic acid can be decarboxylated yield 1-butene or ketonized to yield 5-nonanone. The 5-nonanone can be hydrodeoxygenated to yield nonane, or 5-nonanone can be reduced to yield 5-nonanol. The 5-nonanol can be dehydrated to yield nonene, which can be dimerized to yield a mixture of C.sub.9 and C.sub.18 olefins, which can be hydrogenated to yield a mixture of alkanes.

  4. A new process for the valorisation of a bio-alcohol. The oxidehydration of 1-butanol into maleic anhydride

    Energy Technology Data Exchange (ETDEWEB)

    Caldarelli, A.; Cavani, F.; Garone, O.; Pavarelli, G. [Bologna Univ. (Italy). Dipt. di Chimica Industriale e dei Materiali; Bologna Univ. (Italy). CIRCC, Research Unit; Dubois, J.L. [ARKEMA, Colombes (France); Mitsova, I.; Simeonova, L. [JSC, Russe (Bulgaria). Orgachim

    2012-07-01

    This paper deals with a study on the gas-phase transformation of 1-butanol into maleic anhydride, using different types of catalysts. Indeed, catalytic acid properties are needed to dehydrate 1-butanol into 1-butene, whereas redox-type properties are required for the oxidation of the olefin into maleic anhydride. The two types of active sites can be combined in bifunctional systems, showing both acid and redox-type properties. We found that vanadyl pyrophosphate catalyzes the one-pot reaction, giving a maximum selectivity to maleic anhydride of 28%. In fact, various side reactions contributed to the formation of by-products, eg, 1-butanol (oxidative) dehydrogenation into butyraldehyde, formation of light carboxylic acids and carbon oxides, and condensation of unsaturated C{sub 4} intermediates (butenes and butadiene) with the formed maleic anhydride to yield heavier compounds. (orig.)

  5. Chromium oxide catalysts in the dehydrogenation of alkanes

    OpenAIRE

    Airaksinen, Sanna

    2005-01-01

    Light alkenes, such as propene and butenes, are important intermediates in the manufacture of fuel components and chemicals. The direct catalytic dehydrogenation of the corresponding alkanes is a selective way to produce these alkenes and is frequently carried out using chromia/alumina catalysts. The aim of this work was to obtain structure–activity information, which could be utilised in the optimisation of this catalytic system. The properties of chromia/alumina catalysts were investigated ...

  6. The Thermodynamic Conjugation Stabilization of 1,3-Butadiyne Is Zero

    Science.gov (United States)

    Rogers, Donald W.; Zavitsas, Andreas A.; Matsunaga, Nikita

    2010-01-01

    Many textbooks point out that the thermodynamic stabilization enthalpy of 1 mol of 1,3-butadiene relative to 2 mol of 1-butene or to 1 mol of 1,4-pentadiene is slightly less than 4 kcal mol[superscript -1], owing to conjugation between the double bonds in the 1,3 configuration. It is reasonable to suppose that the analogous thermochemical…

  7. Olefin hydroformylation catalysis with RuCl2(DMSO4.

    Directory of Open Access Journals (Sweden)

    Marisela Reyes*

    2008-05-01

    Full Text Available The RuCl2(DMSO4 complex was used as catalytic precursor in olefin hydroformylation reactions, giving good percent yield and better selectivity for linear aldehydes. The reactions were tested in homogeneous medium and biphasic organic solvent/ water systems. The substrates tried were 1-hexene, cyclohexene, 2-methyl-2-pentene, 2,3-dimethyl-2-butene; binary mixtures and synthetic naphtha and real naphtha. The activity is better for linear olefins compared with substituted olefins.

  8. Synthesis and Antimicrobial Evaluation of Some Pyrazole Derivatives

    OpenAIRE

    Nagwa Mohamed Mahrous Hamada; Essam Mohamed Sharshira

    2012-01-01

    Reaction of a series of (E)-3-phenyl-4-(p-substituted phenyl)-3-buten-2-ones with p-sulfamylphenyl hydrazine in glacial acetic acid gave the corresponding hydrazones, subsequent treatment of which with 30% HCl afforded pyrazole-1-sulphonamides. On the other hand, refluxing of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide in ethanol containing a few drops of acetic acid gave pyrazoline-1-thiocarboxamides an...

  9. Regiospecific synthesis of new non-condensed heteropolycyclic systems from {beta}-heteroaryl-{beta}-methoxyvinyl trihalomethyl ketones

    Energy Technology Data Exchange (ETDEWEB)

    Bonacorso, Helio G.; Oliveira, Marli R.; Costa, Michelle B.; Silva, Leticia B. da; Zanatta, Nilo; Martins, Marcos A.P.; Flores, Alex F.C. [Universidade Federal de Santa Maria, RS (Brazil). Dept. de Quimica]. E-mail: heliogb@base.ufsm.br

    2005-07-15

    A novel series of twelve heteroaroyl-2-pyrazolines trihalomethyl and substituted heteroaryl, as non-condensed heteropolycyclic systems, have been synthesized in one-step in 50-78% yield from the regiospecific cyclo condensation reaction of 1,1,1-trifluoro(chloro)-4-methoxy-4-(2-furyl)- and 4-(2-thienyl)-3-buten-2-ones ({beta}-alkoxyvinyl trihalometil ketones) with furoic hydrazide, 2-thiophenecarboxylic hydrazide and isonicotinic acid hydrazide (heteroaroylhydrazines) under mild conditions in methanol as solvent. (author)

  10. Regiospecific synthesis of new non-condensed heteropolycyclic systems from β-heteroaryl-β-methoxyvinyl trihalomethyl ketones

    International Nuclear Information System (INIS)

    A novel series of twelve heteroaroyl-2-pyrazolines trihalomethyl and substituted heteroaryl, as non-condensed heteropolycyclic systems, have been synthesized in one-step in 50-78% yield from the regiospecific cyclo condensation reaction of 1,1,1-trifluoro(chloro)-4-methoxy-4-(2-furyl)- and 4-(2-thienyl)-3-buten-2-ones (β-alkoxyvinyl trihalometil ketones) with furoic hydrazide, 2-thiophenecarboxylic hydrazide and isonicotinic acid hydrazide (heteroaroylhydrazines) under mild conditions in methanol as solvent. (author)

  11. Regenerierung desaktivierter Zeolith-Katalysatoren durch Hydrocracken der Koksdeposite

    OpenAIRE

    Josl, Rouven

    2005-01-01

    In dieser Arbeit wurde die Regenerierung von in der Isobutan/Buten-Alkylierung verkokten Zeolith-Katalysatoren durch Hydrocracken der Koksdeposite untersucht. Diese Regenerierungsmethode wurde gewählt, da sie bei geringerer Temperatur durchgeführt werden kann als die oxidative Regenerierung. Ein weiterer Vorteil der Methode ist, dass die Deposite zu Kohlenwasserstoffen gespalten werden, die wiederum als Edukte in der Alkylierung eingesetzt werden können. Als Grundlage für die späteren Ex...

  12. Evaluation of Ferrocene Derivatives as Burn Rate Modifiers in AP/HTPB-Based Composite Propellants

    OpenAIRE

    G. M. Gore; K. R. Tipare; R. G. Bhatewara; U.S. Prasad; Manoj Gupta; S. K. Mane

    1999-01-01

    Some ferrocene derivatives like 2,4-dinitrophenylhydrazine derivative of acetyl ferrocene, 1-pyrrolidinylmethyl ferrocene, di-ter-butyl ferrocene and 1,3-diferrocenyl-l-butene (DFB) have been synthesised and characterised by infrared, nuclear magnetic resonance, ultraviolet, iron content, etc. To study the effect of their incorporation on performance, ammonium perchlorate/hydroxyl-terminated polybutadiene-based composite propellants containing these derivatives have been prepared and studied ...

  13. Synthesis and DPPH Radical Scavenging Activity of Prenylated Phenol Derivatives

    OpenAIRE

    Héctor Carrasco; Luis Espinoza; Marcela Carvajal; Cesar González; Alejandra Vergara; Lautaro Taborga; Evelyn Baeza; Karen Catalán; Mauricio Osorio; Jacqueline Aravena

    2012-01-01

    The synthesis of twenty six prenylated phenols derivatives is reported. These compounds were obtained under mild conditions via Electrophilic Aromatic Substitution (EAS) coupling reactions between phenol derivatives containing electron-donor subtituents and 3-methyl-2-buten-1-ol using BF3×OEt2. Dialkylations were also produced with this method. The formation of a chroman ring by intramolecular cyclization between a sp2 carbon from the prenyl group with the hydroxyl substituent in the ortho po...

  14. Metal catalyzed synthesis of hyperbranched ethylene and/or .alpha.-olefin polymers

    Science.gov (United States)

    Sen, Ayusman; Kim, Jang Sub; Pawlow, James H.; Murtuza, Shahid; Kacker, Smita; Wojcinski, III, Louis M.

    2001-01-01

    Oily hyperbranched polymers derived from ethylene, propylene, butene and/or a C.sub.5 -C.sub.24 .alpha.-olefin, and a method for their synthesis, are disclosed. The polymers have non-regular microstructures and are characterized by a ratio ({character pullout})of methyl hydrogens centered around 0.85 ppm on the 1H-NMR spectra of the polymers relative to total aliphatic hydrogens of from about 0.40 to about 0.65 for polymers derived from ethylene or butene, and a ratio ({character pullout})of from greater than 0.50 to about 0.65 for polymers derived from propylene. A method for grafting hyperbranched polymers derived from ethylene, propylene, butene and/or a C.sub.5 -C.sub.24 .alpha.-olefin onto aromatic rings in organic molecules and polymers, and the resulting grafted materials, are also disclosed. The hyperbranched polymers and grafted materials are useful, for example, as lubricants and lubricant additives.

  15. Kinetic and mechanistic study of the atmospheric reaction of MBO331 with Cl atoms

    Science.gov (United States)

    Rodríguez, Diana; Rodríguez, Ana; Garzón, Andrés; Granadino-Roldán, José M.; Soto, Amparo; Aranda, Alfonso; Notario, Alberto

    2012-12-01

    The present work deals with the reaction of 3-methyl-3-buten-1-ol (MBO331) with Cl atoms, which has been investigated by gas chromatography with flame ionization detection (GC-FID) at atmospheric pressure in N2 or air, using the relative rate technique. The rate constant reaction at 298 ± 1 K was found to be (5.01 ± 0.70) × 10-10 cm3 molecule-1 s-1, using cyclohexane, octane and 1-butene as a reference compounds. The temperature dependence for the reaction was studied within the 298-333 K range. Additionally, a product identification under atmospheric conditions has been performed for the first time by GC-MS, with 3-methyl-3-butenal, methacrolein and chloroacetone being observed as degradation products. A theoretical study on the reaction at the QCISD(T)/6-311G**//MP2/6-311G** level was also carried out to obtain more information on the mechanism. From the theoretical study it can be predicted that Cl addition to the double bond proceeds through lower energy barriers than H-abstraction pathways and therefore is energetically favoured. Finally, atmospheric implications of the results obtained are discussed.

  16. A New Process for Maleic Anhydride Synthesis from a Renewable Building Block: The Gas-Phase Oxidehydration of Bio-1-butanol.

    Science.gov (United States)

    Pavarelli, Giulia; Velasquez Ochoa, Juliana; Caldarelli, Aurora; Puzzo, Francesco; Cavani, Fabrizio; Dubois, Jean-Luc

    2015-07-01

    We investigated the synthesis of maleic anhydride by oxidehydration of a bio-alcohol, 1-butanol, as a possible alternative to the classical process of n-butane oxidation. A vanadyl pyrophosphate catalyst was used to explore the one-pot reaction, which involved two sequential steps: 1) 1-butanol dehydration to 1-butene, catalysed by acid sites, and 2) the oxidation of butenes to maleic anhydride, catalysed by redox sites. A non-negligible amount of phthalic anhydride was also formed. The effect of different experimental parameters was investigated with chemically sourced 1-butanol, and the results were then confirmed by using genuinely bio-sourced 1-butanol. In the case of bio-1-butanol, however, the purity of the product remarkably affected the yield of maleic anhydride. It was found that the reaction mechanism includes the oxidation of butenes to crotonaldehyde and the oxidation of the latter to either furan or maleic acid, both of which are transformed to produce maleic anhydride.

  17. A catalytic biofuel production strategy involving separate conversion of hemicellulose and cellulose using 2-sec-butylphenol (SBP) and lignin-derived (LD) alkylphenol solvents.

    Science.gov (United States)

    Kim, Sunghoon; Han, Jeehoon

    2016-03-01

    A strategy in which the hemicellulose and cellulose fractions of lignocellulosic biomass are converted separately to jet fuel-range liquid hydrocarbon fuels (butene oligomers) through catalytic processes is developed. Dilute sulfuric acid (SA)-catalyzed pretreatment fractionates the first biomass into cellulose and hemicellulose-derived xylose, and these are then converted separately to levulinic acid (LA) using 2-sec-butylphenol (SBP) and lignin-derived (LD) alkylphenol solvents, respectively. LA is upgraded catalytically to butene oligomers via γ-valerolactone (GVL) and butene intermediates. Separation subsystems are designed to recover the alkylphenol solvents and biomass-derived intermediates (LA and GVL) for combination with the catalytic conversion subsystems of hemicellulose, cellulose, and lignin. In addition, a heat exchanger network (HEN) design is presented to satisfy the energy requirements of the integrated process from combustion of biomass residues (degradation products). Finally, a technoeconomic analysis shows that the proposed process ($3.37/gallon of gasoline) is an economically competitive alternative to current biofuel production approaches.

  18. Photoionization mass spectrometer studies of the collisionally stabilized product distribution in the reaction of OH radicals with selected alkenes at 298 K

    International Nuclear Information System (INIS)

    The reactions of OH radicals with propene, 1-butene, and 1-pentene have been studied in a discharge flow system coupled to a photoionization mass spectrometer. At total pressures near 2 torr a collisionally stabilized OH-alkene adduct was observed in each case. For 1-butene and 1-pentene the radicals arising from abstraction of a hydrogen atom from the alkene by OH were also observed and their absolute concentrations measured under controlled conditions. Contributions of the abstraction pathway to the overall reaction were as follows: propene, 3P) and OH taken from the literature and/or measured in this work. Rate constants (in cm3 molecule-1 s-1) obtained as part of this study include the following: k/sub OH+butene/ = (3.0 +- 0.4) x 10-11; k/sub OH+1-pentene/ = (2.9 +- 0.4) x 10-11, (2.87 +- 0.13) x 10-11 (50 torr of Ar); k/sub O(3P)+propene/ = (4.4 +- 0.6) x 10-12;k/sub O(3P)+1-pentene/ = (4.7 +- 0.5) x 10-12; k/sub OH+CS2/ less than or equal to 5 x 10-14, at 298 K and 2 torr of He total pressure unless otherwise stated. 5 figures, 2 tables

  19. Phase behavior for the poly(alkyl methacrylate)+supercritical CO{sub 2}+DME mixture at high pressures

    Energy Technology Data Exchange (ETDEWEB)

    Choi, Yong-Seok; Chio, Sang-Won; Byun, Hun-Soo [Chonnam National University, Yeosu (Korea, Republic of)

    2016-01-15

    The phase behavior curves of binary and ternary system were measured for poly(alkyl methacrylate) in supercritical CO{sub 2}, as well as for the poly(alkyl methacrylate)+dimethyl ether (DME) (or 1-butene) in CO{sub 2}. The solubility curves are reported for the poly(alkyl methacrylate)+DME in supercritical CO{sub 2} at temperature from (300 to 465) K and a pressure from (3.66 to 248) MPa. Also, The high-pressure static-type apparatus of cloud-point curve was tested by comparing the measured phase behavior data of the poly(methyl methacrylate) [PMMA]+CO{sub 2}+20.0 and 30.4 wt% methyl methacrylate (MMA) system with literature data of 10.4, 28.8 and 48.4 wt% MMA concentration. The phase behavior data for the poly(alkyl methacrylate)+CO{sub 2}+DME mixture were measured in changes of the pressure-temperature (p, T) slope and with DME concentrations. Also, the cloud-point pressure for the poly(alkyl methacrylate)+1- butene solution containing supercritical CO{sub 2} shows from upper critical solution temperature (UCST) region to lower critical solution temperature (LCST) region at concentration range from (0.0 to 95) wt% 1-butene at below 455 K and at below 245MPa.

  20. Development of a pulsed uniform supersonic gas expansion system based on an aerodynamic chopper for gas phase reaction kinetic studies at ultra-low temperatures.

    Science.gov (United States)

    Jiménez, E; Ballesteros, B; Canosa, A; Townsend, T M; Maigler, F J; Napal, V; Rowe, B R; Albaladejo, J

    2015-04-01

    A detailed description of a new pulsed supersonic uniform gas expansion system is presented together with the experimental validation of the setup by applying the CRESU (French acronym for Cinétique de Réaction en Ecoulement Supersonique Uniforme or Reaction Kinetics in a Uniform Supersonic Flow) technique to the gas-phase reaction of OH radicals with 1-butene at ca. 23 K and 0.63 millibars of helium (carrier gas). The carrier gas flow, containing negligible mixing ratios of OH-precursor and 1-butene, is expanded from a high pressure reservoir (337 millibars) to a low pressure region (0.63 millibars) through a convergent-divergent nozzle (Laval type). The novelty of this experimental setup is that the uniform supersonic flow is pulsed by means of a Teflon-coated aerodynamic chopper provided with two symmetrical apertures. Under these operational conditions, the designed Laval nozzle achieves a temperature of (22.4 ± 1.4) K in the gas jet. The spatial characterization of the temperature and the total gas density within the pulsed uniform supersonic flow has also been performed by both aerodynamical and spectroscopic methods. The gas consumption with this technique is considerably reduced with respect to a continuous CRESU system. The kinetics of the OH+1-butene reaction was investigated by the pulsed laser photolysis/laser induced fluorescence technique. The rotation speed of the disk is temporally synchronized with the exit of the photolysis and the probe lasers. The rate coefficient (k(OH)) for the reaction under investigation was then obtained and compared with the only available data at this temperature. PMID:25933898

  1. Intermediate species measurement during iso-butanol auto-ignition

    KAUST Repository

    Ji, Weiqi

    2015-10-01

    © 2015 The Combustion Institute.Published by Elsevier Inc. All rights reserved. This work presents the time histories of intermediate species during the auto-ignition of iso-butanol at high pressure and intermediate temperature conditions obtained using a rapid compression machine and recently developed fast sampling system. Iso-butanol ignition delays were acquired for iso-butanol/O2 mixture with an inert/O2 ratio of 7.26, equivalence ratio of 0.4, in the temperature range of 840-950 K and at pressure of 25 bar. Fast sampling and gas chromatography were used to acquire and quantify the intermediate species during the ignition delay of the same mixture at P = 25.3 bar and T = 905 K. The ignition delay times and quantitative measurements of the mole fraction time histories of methane, ethene, propene, iso-butene, iso-butyraldehyde, iso-butanol, and carbon monoxide were compared with predictions from the detailed mechanisms developed by Sarathy et al., Merchant et al., and Cai et al. It is shown that while the Sarathy mechanism well predicts the overall ignition delay time, it overpredicts ethene by a factor of 6-10, underpredicts iso-butene by a factor of 2, and overpredicts iso-butyraldehyde by a factor of 2. Reaction path and sensitivity analyses were carried out to identify the reactions responsible for the observed inadequacy. The rates of iso-butanol hydrogen atom abstraction by OH radical and the beta-scission reactions of hydroxybutyl radicals were updated based on recently published quantum calculation results. Significant improvements were achieved in predicting ignition delay at high pressures (25 and 30 bar) and the species concentrations of ethene and iso-butene. However, the updated mechanism still overpredicts iso-butyraldehyde concentrations. Also, the updated mechanism degrades the prediction in ignition delay at lower pressure (15 bar) compared to the original mechanism developed by Sarathy et al.

  2. Biogenic Emissions of Light Alkenes from a Coniferous Forest

    Science.gov (United States)

    Rhew, R. C.; Turnipseed, A. A.; Martinez, L.; Shen, S.; De Gouw, J. A.; Warneke, C.; Koss, A.; Lerner, B. M.; Miller, B. R.; Smith, J. N.; Guenther, A. B.

    2014-12-01

    Alkenes are reactive hydrocarbons that play important roles in the photochemical production of tropospheric ozone and in the formation of secondary organic aerosols. The light alkenes (C2-C4) originate from both biogenic and anthropogenic sources and include C2H4 (ethene), C3H6 (propene) and C4H8 (1-butene, 2-butene, 2-methylpropene). Light alkenes are used widely as chemical feedstocks because their double bond makes them versatile for industrial reactions. Their biogenic sources are poorly characterized, with most global emissions estimates relying on laboratory-based studies; net ecosystem emissions have been measured at only one site thus far. Here we report net ecosystem fluxes of light alkenes and isoprene from a semi-arid ponderosa pine forest in the Rocky Mountains of Colorado, USA. Canopy scale fluxes were measured using relaxed eddy accumulation (REA) techniques on the 28-meter NCAR tower in the Manitou Experimental Forest Observatory. Updrafts and downdrafts were determined by sonic anemometry and segregated into 'up' and 'down' reservoirs over the course of an hour. Samples were then measured on two separate automated gas chromatographs (GCs). The first GC measured light hydrocarbons (C2-C6 alkanes and C2-C5 alkenes) by flame ionization detection (FID). The second GC measured halocarbons (methyl chloride, CFC-12, and HCFC-22) by electron capture detection (ECD). Additional air measurements from the top of the tower included hydrocarbons and their oxidation products by Proton Transfer Reaction Mass Spectrometry (PTR-MS). Three field intensives were conducted during the summer of 2014. The REA flux measurements showed that ethene, propene and the butene emissions have significant diurnal cycles, with maximum emissions at midday. The light alkenes contribute significantly to the overall biogenic source of reactive hydrocarbons and have a temporal variability that may be associated with physical and biological parameters. These ecosystem scale measurements

  3. Ice core records of monoterpene- and isoprene-SOA tracers from Aurora Peak in Alaska since 1660s: Implication for climate change variability in the North Pacific Rim

    Science.gov (United States)

    Pokhrel, Ambarish; Kawamura, Kimitaka; Ono, Kaori; Seki, Osamu; Fu, Pingqing; Matoba, Sumio; Shiraiwa, Takayuki

    2016-04-01

    Monoterpene and isoprene secondary organic aerosol (SOA) tracers are reported for the first time in an Alaskan ice core to better understand the biological source strength before and after the industrial revolution in the Northern Hemisphere. We found significantly high concentrations of monoterpene- and isoprene-SOA tracers (e.g., pinic, pinonic, and 2-methylglyceric acids, 2-methylthreitol and 2-methylerythritol) in the ice core, which show historical trends with good correlation to each other since 1660s. They show positive correlations with sugar compounds (e.g., mannitol, fructose, glucose, inositol and sucrose), and anti-correlations with α-dicarbonyls (glyoxal and methylglyoxal) and fatty acids (e.g., C18:1) in the same ice core. These results suggest similar sources and transport pathways for monoterpene- and isoprene-SOA tracers. In addition, we found that concentrations of C5-alkene triols (e.g., 3-methyl-2,3,4-trihydroxy-1-butene, cis-2-methyl 1,3,4-trihydroxy-1-butene and trans-2-methyl-1,3,4-trihydroxy-1-butene) in the ice core have increased after the Great Pacific Climate Shift (late 1970s). They show positive correlations with α-dicarbonyls and fatty acids (e.g., C18:1) in the ice core, suggesting that enhanced oceanic emissions of biogenic organic compounds through the marine boundary layer are recorded in the ice core from Alaska. Photochemical oxidation process for these monoterpene- and isoprene-/sesquiterpene-SOA tracers are suggested to be linked with the periodicity of multi-decadal climate oscillations and retreat of sea ice in the Northern Hemisphere.

  4. Synthesis, stability constants and electronic spectral studies of ternary complexes of Pr(III) with histidine and diols

    International Nuclear Information System (INIS)

    The mixed ligand complexes of the type MAB, MA2B and MaB2 where M = Pr(III), A = histidine and B = ethanediol, prop-1,2-diol, 2-butene-1, 4-diol, but-2,3-diol, pent-1,5-diol and hex-1,6-diol have been investigated by alkalimetric titrations. The overall stability constants have been evaluated at 30+1degC (μ = 0.2MKNO3). The absorption spectra of some praseodymium(III) ternary complexes in solution have been used to calculate energy interaction and intensity parameters. The low intensity of the pseudohypersensitive transition suggests higher coordination number. (author)

  5. Studies on ignition of hydrogen and hydrocarbons

    Science.gov (United States)

    Zheng, Xiaolin

    Control of ignition is crucial for the satisfactory performance of combustors and for the prevention of fires and explosions. The low- to intermediate-temperature chemistry relevant for ignition is rather complex. The level of complexity is further elevated when ignition takes place in a non-uniform medium and as such is also affected by convective-diffusive transport. This thesis research is to investigate the chemistry and physics behind the ignition of hydrogen and hydrocarbons in a non-uniform environment. The intricacies of inhomogeneous ignition were illustrated by first considering the ignition of a lean premixed hydrogen/air stream. Experimental results backed by computational simulation show that, compared to the three explosion limits for homogeneous mixtures, ignition now takes place at higher temperatures and exhibits five limits over the pressure range investigated. Furthermore, such a behavior can be largely attributed to the reduced residence time and the self enrichment of the original fuel-lean mixture through the preferential diffusion of the highly mobile hydrogen---a sufficient though not necessary condition. We then examined the non-premixed ignition of a series of hydrocarbons, including ethylene, propylene, 1,3-butadiene, dimethyl ether and the four butene isomers, focusing on the effects of aerodynamic strain rate and pressure. Sensitivity analysis was performed to identify the controlling features for ignition. The key sensitive reactions were found to belong to two groups, namely H2/CO chain reactions and reaction pathways involving the fuel and its intermediates. Ignition was also found to be sensitive to the binary diffusion between fuel and nitrogen. The third component of the thesis is a study through ab initio calculations on the thermochemistry analysis of three important pathways for ignition of the butene isomers, and the isobutenyl radical oxidation. For the butene isomers, the calculated reaction rates of these three reaction

  6. Volatile compounds in noni (Morinda citrifolia L. at two ripening stages Compostos voláteis em noni (Morinda citrifolia L. em dois estágios de maturação

    Directory of Open Access Journals (Sweden)

    Jorge Antonio Pino

    2010-03-01

    Full Text Available The volatile components of noni at two ripening stages were isolated by headspace solid-phase microextraction using 65 µm Polydimethylsiloxane-Divinylbenzene (PDMS/DVB fibers and analyzed using GC/MS. Both maturation stages had several compounds in common. Ninety-six compounds were identified, from which octanoic acid ( 70% of total extract and hexanoic acid ( 8% of total extract were found to be the major constituents. Due to noni maturation, octanoic acid, decanoic acid and 2E-nonenal decreased their concentrations, while some esters (methyl hexanoate, methyl octanoate, ethyl octanoate and methyl 4E-decenoate, which their fruity odor notes, increased their contents. Two unsaturated esters, reported for the first time in this fruit, 3-methyl-3-buten-1-yl hexanoate and 3-methyl-3-buten-1-yl octanoate, significantly decreased their concentration in the ripe to over-ripe fruits.Los compuestos volátiles del noni en los dos estados de madurez se aislaron mediante microextracción en fase sólida por headspace con fibras de 65 mm Polidimetilsiloxano-Divinilbenceno (PDMS/DVB y se analizaron por cromatografía de gases/espectrometría de masas. Ambos estados de madurez poseen numerosos constituyentes en común. Se identificaron 96 compuestos, de los cuales el ácido octanoico ( 70% del extracto total y ácido hexanoico ( 8% del extracto total fueron los componentes mayoritarios. Debido a la maduración del noni, el ácido octanoico, ácido decanoico y 2E-nonenal disminuyeron su contenido, mientras que algunos ésteres (hexanoato de metilo, octanoato de metilo, octanoato de etilo y 4E-decenoato de metilo, con sus olororosas notas frutales, incrementaron la concentración. Dos ésteres insaturados, reportados por primera vez en esta fruta, hexanoato de 3-metil-3-buten-1-ilo y octanoato de 3-metil-3-buten-1-ilo, disminuyeron significativamente su concentración al pasar la fruta del estado maduro al sobremaduro.

  7. 1,3-Butadiene hydrogenation on pd-supported systems: geometric effects

    Directory of Open Access Journals (Sweden)

    Souza P.R.N.

    2002-01-01

    Full Text Available A strong metal support interaction (SMSI effect was observed on Pd/Nb2O5 and Pd/TiO2 catalysts, and it produces small, exposed Pd ensembles. A decrease in the trans/cis 2-butene ratio was observed after reduction at 773 K. Selectivity changes were ascribed to the decoration model. Theoretical models were developed based on semi-empirical molecular-orbital calculations for 1,3-butadiene and Pd n clusters. Experimental results are in agreement with our theoretical model, which proposes a greater stabilization of the cisoid intermediate on small Pd ensembles.

  8. XAFS Study of the Photo-Active Site of Mo/MCM-41

    International Nuclear Information System (INIS)

    An Mo/MCM-41 catalyst was prepared and used for study of propene and 1-butene photo-metathesis reactions. XAFS analysis revealed that hydrogen reduction leads to a decreased role for the Mo=O site. The Mo-O site plays an important role for the olefin photo-metathesis reaction on the H2 reduced Mo/MCM-41. From EXAFS analysis, the active site of photo-metathesis reaction is the Mo=O part for oxidized Mo/MCM-41, whereas it is the Mo-O site for reduced Mo/MCM-41

  9. XAFS Study of the Photo-Active Site of Mo/MCM-41

    Science.gov (United States)

    Miyamoto, Daisuke; Ichikuni, Nobuyuki; Shimazu, Shogo

    2007-02-01

    An Mo/MCM-41 catalyst was prepared and used for study of propene and 1-butene photo-metathesis reactions. XAFS analysis revealed that hydrogen reduction leads to a decreased role for the Mo=O site. The Mo-O site plays an important role for the olefin photo-metathesis reaction on the H2 reduced Mo/MCM-41. From EXAFS analysis, the active site of photo-metathesis reaction is the Mo=O part for oxidized Mo/MCM-41, whereas it is the Mo-O site for reduced Mo/MCM-41.

  10. End-labeled amino terminated monotelechelic glycopolymers generated by ROMP and Cu(I-catalyzed azide–alkyne cycloaddition

    Directory of Open Access Journals (Sweden)

    Ronald Okoth

    2013-03-01

    Full Text Available Functionalizable monotelechelic polymers are useful materials for chemical biology and materials science. We report here the synthesis of a capping agent that can be used to terminate polymers prepared by ring-opening metathesis polymerization of norbornenes bearing an activated ester. The terminating agent is a cis-butene derivative bearing a Teoc (2-trimethylsilylethyl carbamate protected primary amine. Post-polymerization modification of the polymer was accomplished by amidation with an azido-amine linker followed by Cu(I-catalyzed azide–alkyne cycloaddition with propargyl sugars. Subsequent Teoc deprotection and conjugation with pyrenyl isothiocyanates afforded well-defined end-labeled glycopolymers.

  11. Application of olefin metathesis in petrochemistry

    Energy Technology Data Exchange (ETDEWEB)

    Warwel, S.

    1979-01-01

    A survey covers the catalysts used in olefin metathesis; olefin types which undergo metathesis, e.g., ring-opening metathetic polymerization of cycloolefins; equilibria and side reactions; the Phillips Triolefin process for 2-butene production; the Shell Higher Olefin Process (SHOP) for the production of C/sub 11/-C/sub 14/ ..cap alpha..-olefins; the Phillips Petroleum 225 ton/yr process for the conversion of trimethylpentane to neohexene, which is used in gasoline and pharmaceutical manufacture; the production of isoprene precursors; and various other metathesis reactions used in synthesizing specific olefins.

  12. Synthesis of Branch Fluorinated Cationic Surfactant and Surface Properties

    Directory of Open Access Journals (Sweden)

    Hongke Wu

    2014-01-01

    Full Text Available A novel fluorinated quaternary ammonium salt cationic surfactant N,N,N-trimethyl-2-[[4-[[3,4,4,4-tetrafluoro-2-[1,2,2,2-tetrafluoro-1-(trifluoromethylethyl]-1,3-bis(tri-fluoromethyl-1-buten-1-yl]oxy]-benzoyl]amino]-iodide (FQAS was synthesized successfully, and its structure was characterized by FTIR, 1H-NMR, 19F-NMR, and MS. The surface activities of FQAS and the effect of temperature, electrolyte, and combination with hydrocarbon surfactant were investigated. The results showed that FQAS exhibited excellent surface activity and combination with hydrocarbon surfactant.

  13. A Ruthenium/Phosphoramidite-Catalyzed Asymmetric Interrupted Metallo-ene Reaction.

    Science.gov (United States)

    Trost, Barry M; Ryan, Michael C

    2016-03-01

    Allylic chlorides prepared from commercially available trans-1,4-dichloro-2-butene were converted to trans-disubstituted 5- and 6-membered ring systems with perfect diastereoselectivity and high enantioselectivity under chiral ruthenium catalysis. These products contain stereodefined secondary and tertiary alcohols that originate from the trapping of an alkylruthenium intermediate with adventitious water. Key to the success of this transformation was the development of a new BINOL-based phosphoramidite ligand containing bulky substitution at its 3- and 3'-positions. As a demonstration of product utility, diastereoselective Friedel-Crafts reactions were performed on the chiral benzylic alcohols in high yield and stereoselectivity. PMID:26899551

  14. Aldol condensation of acyclic ketones with benzaldehyde and subsequent cyclodehydration to form indenes over halide cluster catalysts

    OpenAIRE

    黒川, 秀樹; 千原, 貞次

    2006-01-01

    When a molecular halide cluster [(Ta6Cl12)C-12(H2O)(4)]-4H(2)O (1)/SiO2 was treated in a helium stream above 200 degrees C, it catalyzed the aldol condensation of acetone with benzaldehyde to yield E-4-phenyl-3-buten-2-one. The bromide cluster of Ta and chloride clusters of Nb, Mo, and W of the same octahedral metal framework also catalyzed the reaction. 3,3-Dimethyl-2-butanone combined with benzaldehyde similarly yielded the corresponding aldol condensation product over 1/SiO2 at 400 degrees...

  15. Volatile metabolites from actinomycetes

    DEFF Research Database (Denmark)

    Scholler, C.E.G.; Gurtler, H.; Pedersen, R.;

    2002-01-01

    , sulfur compounds, and isoprenoid compounds. Among the most frequently produced compounds were isoprene, acetone, 1-butanol, 2-methyl-1-propanol,3-methyl-3-buten-1-ol, 3-methyl-1-butanol, 2-methyl-1-butanol, cyclopentanone, dimethyl disulfide, dimethyl trisulfide, 2-phenylethanol, and geosmin....... The relationship between the excretion of geosmin and the production of spores was examined for one isolate. A good correlation between headspace geosmin and the number of spores was observed, suggesting that VOCs could be used to indicate the activity of these microorganisms in heterogeneous substrates....

  16. Tungsten imido catalysts for selective ethylene dimerisation.

    Science.gov (United States)

    Wright, Christopher M R; Turner, Zoë R; Buffet, Jean-Charles; O'Hare, Dermot

    2016-02-14

    A tungsten imido complex W(NDipp)Me3Cl (Dipp = 2,6-(i)Pr-C6H3) is active for the selective dimerisation of ethylene to yield 1-butene under mild conditions. Immobilisation and activation of W(NDipp)Cl4(THF) on layered double hydroxides, silica or polymethylaluminoxane yields active solid state catalysts for the selective dimerisation of ethylene. The polymethylaluminoxane-based catalyst displays a turnover frequency (4.0 molC2H4 molW(-1) h(-1)) almost 7 times that of the homogeneous catalyst. PMID:26779579

  17. Sequence and modified group analysis on C-terminal modified analogs of endomorphin-2 using electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper, a series of C-terminal modified analogs of endomorphin-2 is investigated using ESI-FT-ICR-MS. Some b, y″, a, and internal ions are found in the CID spectra and slight mass differ- ences between the calculated and observed results are obtained. Moreover, if the C-terminal modified group is t-butyloxy, it can lose butene through McLafferty rearrangement. FT-ICR MS shows its power in peptide sequencing successfully helping us obtain the structure of peptide analogs.

  18. Sequence and modified group analysis on C-terminal modified analogs of endomorphin-2 using electrospray ionization-Fourier transform ion cyclotron resonance mass spectrometer

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    In this paper,a series of C-terminal modified analogs of endomorphin-2 is investigated using ESI-FT-ICR-MS. Some b, y", a, and internal ions are found in the CID spectra and slight mass differences between the calculated and observed results are obtained. Moreover, if the C-terminal modified group is t-butyloxy, it can lose butene through McLafferty rearrangement. FT-ICR MS shows its power in peptide sequencing successfully helping us obtain the structure of peptide analogs.

  19. Tungsten imido catalysts for selective ethylene dimerisation.

    Science.gov (United States)

    Wright, Christopher M R; Turner, Zoë R; Buffet, Jean-Charles; O'Hare, Dermot

    2016-02-14

    A tungsten imido complex W(NDipp)Me3Cl (Dipp = 2,6-(i)Pr-C6H3) is active for the selective dimerisation of ethylene to yield 1-butene under mild conditions. Immobilisation and activation of W(NDipp)Cl4(THF) on layered double hydroxides, silica or polymethylaluminoxane yields active solid state catalysts for the selective dimerisation of ethylene. The polymethylaluminoxane-based catalyst displays a turnover frequency (4.0 molC2H4 molW(-1) h(-1)) almost 7 times that of the homogeneous catalyst.

  20. Carbon isotope separation by absorptive distillation

    International Nuclear Information System (INIS)

    The feasibility of separating carbon isotopes by absorptive distillation has been studied for CO absorption by cryogenic solvents. Phase equilibrium, isotopic separation, and mass transfer data were taken between 77.4 and 114.3 K for the following solvents: propane, propylene, 1:1 propane-propylene, 1-butene, isobutane and nitrogen. Carbon monoxide solubility followed Henry's Law, with a maximum experimental solubility of 6.5 mole percent. Isotopic separation between CO in the gas and liquid phases using hydrocarbon solvents was several times that for pure CO vapor-liquid equilibrium. The maximum observed isotopic separation factor was 1.029 at 77.4 K with the propane-propylene solvent mixture. Mass transfer measurements yielded calculated HETP's of 2 to 5 cm for a possible separation system. An attempt has been made to correlate isotopic separation data using Hildebrand's theory of solutions. The differential absorption of isotopic CO species is expressed as a difference in solubility of the isotopic CO molecules. Data for propane, propylene, and 1-butene show approximately the same behavior at varying temperatures

  1. Transient Spectroscopic Characterization of the Genesis of a Ruthenium Complex Catalyst Supported on Zeolite Y

    Energy Technology Data Exchange (ETDEWEB)

    Ogino, Isao; Gates, Bruce C.; (UCD)

    2010-01-12

    A mononuclear ruthenium complex anchored to dealuminated zeolite HY, Ru(acac)(C{sub 2}H{sub 4}){sup 2+} (acac = acetylacetonate, C{sub 5}H{sub 7}O{sup 2}{sup -}), was characterized in flow reactors by transient infrared (IR) spectroscopy and Ru K edge X-ray absorption spectroscopy. The combined results show how the supported complex was converted into a form that catalyzes ethene conversion to butene. The formation of these species resulted from the removal of acac ligands from the ruthenium (as shown by IR and extended X-ray absorption fine structure (EXAFS) spectra) and the simultaneous decrease in the symmetry of the ruthenium complex, with the ruthenium remaining mononuclear and its oxidation state remaining essentially unchanged (as shown by EXAFS and X-ray absorption near-edge structure spectra). The removal of anionic acac ligands from the ruthenium was evidently compensated by the bonding of other anionic ligands, such as hydride from H2 in the feed stream, to form species suggested to be Ru(H)(C{sub 2}H{sub 4}){sub 2}{sup +}, which is coordinatively unsaturated and inferred to react with ethene, leading to the observed formation of butene in a catalytic process.

  2. High-harmonic spectroscopy of molecular isomers

    Energy Technology Data Exchange (ETDEWEB)

    Wong, M. C. H.; Brichta, J.-P.; Bhardwaj, V. R. [Department of Physics, University of Ottawa, 150 Louis-Pasteur, Ottawa, Ontario, K1N 6N5 (Canada); Spanner, M.; Patchkovskii, S. [National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario, K1A 0R6 (Canada)

    2011-11-15

    We demonstrate that high-order-harmonic generation (HHG) spectroscopy can be used to probe stereoisomers of randomly oriented 1,2-dichloroethylene (C{sub 2}H{sub 2}Cl{sub 2}) and 2-butene (C{sub 4}H{sub 8}). The high-harmonic spectra of these isomers are distinguishable over a range of laser intensities and wavelengths. Time-dependent numerical calculations of angle-dependent ionization yields for 1,2-dichloroethylene suggest that the harmonic spectra of molecular isomers reflect differences in their strong-field ionization. The subcycle ionization yields for the cis isomer are an order of magnitude higher than those for the trans isomer. The sensitivity in discrimination of the harmonic spectra of cis- and trans- isomers is greater than 8 and 5 for 1,2-dichloroethylene and 2-butene, respectively. We show that HHG spectroscopy cannot differentiate the harmonic spectra of the two enantiomers of the chiral molecule propylene oxide (C{sub 3}H{sub 6}O).

  3. C2-C10 hydrocarbon emissions from a boreal wetland and forest floor

    Directory of Open Access Journals (Sweden)

    S. Haapanala

    2005-11-01

    Full Text Available Emissions of various C2-C10 hydrocarbons and halogenated hydrocarbons from a boreal wetland and Scots pine forest floor were measured by static chamber technique in south-western Finland. Isoprene was the main non-methane hydrocarbon emitted by the wetland but also small emissions of ethene, propane, propene, 1-butene, 2-methylpropene, butane, pentane and hexane were detected. The isoprene emission from the wetland was observed to follow the commonly used isoprene emission algorithm. The mean emission potential of isoprene was 224 μg m−2 h−1 for the whole season. This is lower than the emission potentials published earlier and probably least partly due to the cold and cloudy weather during the measurements. No emissions of monoterpenes or halogenated hydrocarbons from the wetland were detected. Highest hydrocarbon emissions from the Scots pine forest floor were measured in spring and autumn. Main emitted compounds were monoterpenes. Isoprene emissions were negligible. Highest monoterpene emissions were measured in spring after the snow had melted. Emissions dropped in the summer and increased again in autumn. The total monoterpene emission rates varied from zero to 373 μg m−2 h−1. Probable source for these emissions is decaying plant litter. Also small emissions of chloroform (100–800 ng m−2 h−1, ethene, propane, propene, 2-methylpropene, cis-2-butene, pentane, hexane and heptane were detected.

  4. Carbon isotope separation by absorptive distillation

    International Nuclear Information System (INIS)

    The feasibility of separating carbon isotopes by absorptive distillation has been studied for CO absorption by cryogenic solvents. Phase equilibrium, isotopic separation, and mass transfer data were taken between 77.4 and 114.3 K for the following solvents: propane, propylene, 1:1 propane-propylene, 1-butene, isobutane and nitrogen. Carbon monoxide solubility followed Henry's Law, with a maximum experimental solubility of 6.5 mole per cent. Isotopic separation between CO in the gas and liquid phases using hydrocarbon solvents was several times that for pure CO vapor-liquid equilibrium. The maximum observed isotopic separation factor was 1.029 at 77.4 K with the propane-propylene solvent mixture. Mass transfer measurements yielded calculated HTU's of 2 to 5 cm for a possible separation system. An attempt has been made to correlate isotopic separation data using Hildebrand's theory of solutions. The differential absorption of isotopic CO species is expressed as a difference in solubility of the isotopic CO molecules. Data for propane, propylene, and 1-butene show approximately the same behavior at varying temperatures

  5. Catalytic cracking of lignites

    Energy Technology Data Exchange (ETDEWEB)

    Seitz, M.; Nowak, S.; Naegler, T.; Zimmermann, J. [Hochschule Merseburg (Germany); Welscher, J.; Schwieger, W. [Erlangen-Nuernberg Univ. (Germany); Hahn, T. [Halle-Wittenberg Univ., Halle (Germany)

    2013-11-01

    A most important factor for the chemical industry is the availability of cheap raw materials. As the oil price of crude oil is rising alternative feedstocks like coal are coming into focus. This work, the catalytic cracking of lignite is part of the alliance ibi (innovative Braunkohlenintegration) to use lignite as a raw material to produce chemicals. With this new one step process without an input of external hydrogen, mostly propylene, butenes and aromatics and char are formed. The product yield depends on manifold process parameters. The use of acid catalysts (zeolites like MFI) shows the highest amount of the desired products. Hydrogen rich lignites with a molar H/C ratio of > 1 are to be favoured. Due to primary cracking and secondary reactions the ratio between catalyst and lignite, temperature and residence time are the most important parameter to control the product distribution. Experiments at 500 C in a discontinuous rotary kiln reactor show yields up to 32 wt-% of hydrocarbons per lignite (maf - moisture and ash free) and 43 wt-% char, which can be gasified. Particularly, the yields of propylene and butenes as main products can be enhanced four times to about 8 wt-% by the use of catalysts while the tar yield decreases. In order to develop this innovative process catalyst systems fixed on beads were developed for an easy separation and regeneration of the used catalyst from the formed char. (orig.)

  6. In Situ IR Spectroscopic Study on the Hydrogenation of 1,3-Butadiene on Fresh Mo2C/γ-Al2O3 Catalyst

    Institute of Scientific and Technical Information of China (English)

    Zhang Jing; Wu Weicheng; Liu Shiyang

    2014-01-01

    The surface species formed from the adsorption of 1,3-butadiene and 1,3-butadiene hydrogenation over the fresh Mo2C/γ-Al2O3 catalyst was studied by in situ IR spectroscopy. It is found that 1,3-butadiene adsorption on the Mo2C/γ-Al2O3 catalyst mainly formsπ-adsorbed butadiene (πs andπd) andσ-bonded surface species. These species are adsorbed mainly on the surface Moδ+(0<δ<2) sites as evidenced by co-adsorption of 1,3-butadiene and CO on the fresh Mo2C/γ-Al2O3 catalyst. The IR spectrometric analysis show that hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst produces mainly butane coupled with a small portion of butene. The selectivity of butene during the hydrogenation of 1,3-butadiene over fresh Mo2C/γ-Al2O3 catalyst might be explained by the adsorption mode of adsorbed 1,3-butadiene. Additionally, the active sites of the fresh Mo2C/γ-Al2O3 catalyst may be covered by coke during the hydrogenation reaction of 1,3-butadiene. The treatment with hydrogen at 673 K cannot remove the coke deposits from the surface of the Mo2C/γ-Al2O3 catalyst.

  7. 聚丙烯热灌装瓶专用料的卫生性能研究%Study on Health Performance of Special Polypropylene Material for Hot-filling Bottles

    Institute of Scientific and Technical Information of China (English)

    丁彬红; 张锋

    2016-01-01

    The various factors affecting health properties of two polypropylene (PP)resins for hot-filling bottles, namely ethylene/propylene random copolymer and propylene/butene-1 random copolymer were studied.The results showed that:the sample with butene as comonomer contains low xylene and n-hexane soluble matters, which is more suitable for using in food packaging;injection,stretching and blowing molding makes PP molecular chain has stretch orientation,which substantially increased the crystallinity and reduced the extractable matters in solvent,so as to improve health properties of the product.%对影响乙烯/丙烯无规共聚和丙烯/丁烯-1无规共聚两种聚丙烯热灌装瓶专用树脂卫生性能的各个因素进行了研究。结果表明:以丁烯为共聚单体的试样含有较低的二甲苯和正己烷可溶物,更适合在食品包装上应用;注拉吹成型使聚丙烯分子链拉伸取向,结晶度大幅提高,溶剂可萃取物减少,产品的卫生性能得到改善。

  8. Ruta montana L. leaf essential oil and extracts: characterization of bioactive compounds and suppression of crown gall disease.

    Science.gov (United States)

    Hammami, Inés; Smaoui, Slim; Hsouna, Anis Ben; Hamdi, Naceur; Triki, Mohamed Ali

    2015-01-01

    The aims of this study were to assess the antimicrobial efficacy of the leaf essential oil and the leaf extracts of R. montana against Botrytis cinerea, Fusarium oxysporum, Verticillium dahliae, Aspergillus oryzae and Fusarium solani. The oil (1.000 µg/disk) and the extracts (1.500 µg/disk) revealed a remarkable antifungal effect against the tested plant pathogenic fungi with a radial growth inhibition percentage of 40.0-80.0 % and 5.0-58.0 %, respectively along with their respective MIC values ranging from 100 to 1100 µg/mL and 250 to 3000 µg/mL. The oil had a strong detrimental effect on spore germination of all the tested plant pathogens along with the concentration as well as time-dependent kinetic inhibition of Fusarium oxysporum. Also, the oil exhibited a potent in vivo antifungal effect against Botrytis cinerea on tomato plants. Experiments carried out in plant revealed that the essential oil was slightly effective in suppression of gall formation induced by Agrobacterium tumefaciens on bitter almond. The results of this study indicate that the oil and extracts of R. montana leaves could become natural alternatives to synthetic fungicides to control certain important plant microbial diseases. The GC-MS analysis determined that 28 compounds, which represented 89.03 % of total oil, were present in the oil containing mainly 1-butene, methylcyclopropane, 2-butene and caryophyllene oxide. PMID:26417353

  9. Ice core records of monoterpene- and isoprene-SOA tracers from Aurora Peak in Alaska since 1660s: Implication for climate variability in the North Pacific Rim

    Science.gov (United States)

    Pokhrel, A.; Kawamura, K.; Seki, O.; Ono, K.; Matoba, S.; Shiraiwa, T.

    2015-12-01

    180 m long ice core (ca. 343 years old) was drilled in the saddle of the Aurora Peak of Alaska, which is located southeast of Fairbanks (63.52°N; 146.54°W, elevation: 2,825 m). Samples were directly transported to the Institute of Low Temperature Science, Hokkaido University and have been analyzed for monoterpene- and isoprene-SOA tracers using gas chromatograph (GC; HP 6890) and mass spectrometry system (GC/MS; Agilent). Ice core collected from mountain glacier has not been explored for SOA yet. We found significantly high concentrations of these tracers (e.g., pinic, pinonic, and 2-methylglyceric acids, 2-methylthreitol and 2-methylrythritol), which show historical trends with good correlation with each other since 1665-2008. They show positive correlations with sugar compounds (e.g., mannitol, glucose, fructose, inositol, and sucrose), and anti-correlations with diacids (e.g., C9), w-oxocarboxylic (wC4-wC9), a-dicarbonyls and low molecular weight fatty acids (LFAs) (e.g., C18:1). LFAs show strong correlations with MSA- and nss-SO42- in the same ice core. These results suggest source regions of SOA tracers and ice core chemistry of Alaska. Concentrations of C5-alkene triols (e.g., 3-methyl-2,3,4-trihydroxy-1-butene, cis-2-methyl 1,3,4-trihydroxy-1-butene and trans-2-methyl-1,3,4-trihydroxy-1-butene) have increased in the ice core after the Great Pacific Climate Shift (late 1970's). They show positive correlations with a-dicarbonyls and LFAs (e.g., C18:1) in the ice core, suggesting that enhanced oceanic emissions of biogenic organic compounds through the surface microlayer are recorded in the ice core. Photochemical oxidation processes for these monoterpene- and isoprene-/sesquiterpene-SOA tracers are suggested to be linked with the periodicity of multi-decadal climate oscillations (e.g., North Pacific Index) and we can look at a whole range of environmental parameters in parallel with the robust reconstructed temperature changes in the Northern Hemisphere.

  10. An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

    Energy Technology Data Exchange (ETDEWEB)

    Svelle, Stian

    2004-07-01

    The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the

  11. (Phenoxyimidazolyl-salicylaldimine)iron complexes: synthesis, properties and iron catalysed ethylene reactions.

    Science.gov (United States)

    Yankey, Margaret; Obuah, Collins; Guzei, Ilia A; Osei-Twum, Emmanuel; Hearne, Giovanni; Darkwa, James

    2014-10-01

    The reaction of 2-{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L1), 2,4-di-tert-butyl-6-{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L2) or 4-tert-butyl-2-{[2-(1H-imidazol-4-yl)-ethylimino]-methyl}-phenol (L3) with iron(ii) precursors produced either iron(ii) or iron(iii) complexes, depending on the nature of the anions in the iron(ii) precursor and the ligand. When the anion is chloride and the ligand L1, the product is [(L1)2Fe][FeCl4] (1), but when the anion is triflate (OTf(-)) and the ligand is L2, the product is [(L2)2Fe][OTf]2 (2). With iron(ii) halides and tert-butyl groups on the phenoxy ligands L2 and L3, the iron(iii) complexes [(L2)FeX2] {where X = Cl (3), Br (4) and I = (5)} and [(L3)FeCl2] (6) were formed. Complexes 1-6 were characterised by a combination of elemental analyses, IR spectroscopy and mass spectrometry; and in selected cases (3 and 4) by single crystal X-ray crystallography. The crystal structures of 3 and 4 indicated that the iron(ii) precursors oxidised to iron(iii) in forming complexes 3-6; an observation that was corroborated by the magnetic properties and the (57)Fe Mössbauer spectra of 3 and 4. The iron(iii) complexes 3-6 were used as pre-catalysts for the oligomerisation and polymerisation of ethylene. Products of these ethylene reactions depended on the solvent used. In toluene ethylene oligomerised mainly to 1-butene and was followed by the 1-butene alkylating the solvent to form butyl-toluenes via a Friedel-Crafts alkylation reaction. In chlorobenzene, ethylene oligomerised mainly to a mixture of C4-C12 alkenes. Interestingly small amounts of butyl-chlorobenzenes and hexyl-chlorobenzenes were also formed via a Friedel-Crafts alkylation with butenes and hexenes from the oligomerisation of ethylene. PMID:25111396

  12. Cytotoxic Constituents from the Stems of Clausena lansium (Lour. Skeels

    Directory of Open Access Journals (Sweden)

    Shu Shan Du

    2013-09-01

    Full Text Available Six compounds were isolated from the stems of Clausena lansium (Lour. Skeels by repeated sillica gel column chromatography. Their chemical structures were elucidated on the basic of physicochemical and spectroscopic data. Among them, 8-geranyloxypsolaren (3 and 2-methoxy-1-(3-methyl-buten-1-yl-9H-carbazole-3-carbaldehyde (6 were isolated for the first time from this plant. These compounds were screened for cytotoxicity in human cervical cancer (Hela, leukemia (K562, lung cancer (A549, non-small lung carcinoma (H1299 and liver cancer (SMMC-7721. Within the series of cytotoxic tests, compounds 4–6 displayed potent cytotoxic activity against H1299 and SMMC-7721, with the IC50 values of 6.19 to 26.84 μg/mL.

  13. 6-(Hex-5-enyloxynaphthalene-2-carboxylic acid

    Directory of Open Access Journals (Sweden)

    Md. Lutfor Rahman

    2014-06-01

    Full Text Available The asymmetric unit of the title compound, C17H18O3, comprises three independent molecules with similar geometries. In each molecule, the carbonyl group is twisted away from the napthalene ring system, making dihedral angles of 1.0 (2, 1.05 (19° and 1.5 (2°. The butene group in all three molecules are disordered over two sets of sites, with a refined occupancy ratio of 0.664 (6:0.336 (6. In the crystal, molecules are oriented with respect to their carbonyl groups, forming head-to-head dimers via O—H...O hydrogen bonds. Adjacent dimers are further interconnected by C—H...O hydrogen bonds into chains along the a-axis direction. The crystal structure is further stabilized by weak C—H...π interactions.

  14. Single-Atom Pd₁/Graphene Catalyst Achieved by Atomic Layer Deposition: Remarkable Performance in Selective Hydrogenation of 1,3-Butadiene.

    Science.gov (United States)

    Yan, Huan; Cheng, Hao; Yi, Hong; Lin, Yue; Yao, Tao; Wang, Chunlei; Li, Junjie; Wei, Shiqiang; Lu, Junling

    2015-08-26

    We reported that atomically dispersed Pd on graphene can be fabricated using the atomic layer deposition technique. Aberration-corrected high-angle annular dark-field scanning transmission electron microscopy and X-ray absorption fine structure spectroscopy both confirmed that isolated Pd single atoms dominantly existed on the graphene support. In selective hydrogenation of 1,3-butadiene, the single-atom Pd1/graphene catalyst showed about 100% butenes selectivity at 95% conversion at a mild reaction condition of about 50 °C, which is likely due to the changes of 1,3-butadiene adsorption mode and enhanced steric effect on the isolated Pd atoms. More importantly, excellent durability against deactivation via either aggregation of metal atoms or carbonaceous deposits during a total 100 h of reaction time on stream was achieved. Therefore, the single-atom catalysts may open up more opportunities to optimize the activity, selectivity, and durability in selective hydrogenation reactions. PMID:26268551

  15. Selective hydrogenation of 1,3-butadiene on platinum-copper alloys at the single-atom limit.

    Science.gov (United States)

    Lucci, Felicia R; Liu, Jilei; Marcinkowski, Matthew D; Yang, Ming; Allard, Lawrence F; Flytzani-Stephanopoulos, Maria; Sykes, E Charles H

    2015-01-01

    Platinum is ubiquitous in the production sectors of chemicals and fuels; however, its scarcity in nature and high price will limit future proliferation of platinum-catalysed reactions. One promising approach to conserve platinum involves understanding the smallest number of platinum atoms needed to catalyse a reaction, then designing catalysts with the minimal platinum ensembles. Here we design and test a new generation of platinum-copper nanoparticle catalysts for the selective hydrogenation of 1,3-butadiene,, an industrially important reaction. Isolated platinum atom geometries enable hydrogen activation and spillover but are incapable of C-C bond scission that leads to loss of selectivity and catalyst deactivation. γ-Alumina-supported single-atom alloy nanoparticle catalysts with <1 platinum atom per 100 copper atoms are found to exhibit high activity and selectivity for butadiene hydrogenation to butenes under mild conditions, demonstrating transferability from the model study to the catalytic reaction under practical conditions. PMID:26449766

  16. Homo-polymerization of α-Olefins and Co-polymerization of Higher α-Olefins with Ethylene in the Presence of CpTiCl2(OC6H4X-p/MAO Catalysts (X = CH3, Cl

    Directory of Open Access Journals (Sweden)

    Z. Wieczorek

    2005-07-01

    Full Text Available Cyclopentadienyl-titanium complexes containing –OC6H4X ligands (X = Cl,CH3 activated with methylaluminoxane (MAO were used in the homo-polymerizationof ethylene, propylene, 1-butene, 1-pentene, 1-butene, and 1-hexene, and also in co-polymerization of ethylene with the α-olefins mentioned. The -X substituents exhibitdifferent electron donor-acceptor properties, which is described by Hammett’s factor (σ.The chlorine atom is electron acceptor, while the methyl group is electron donor. Thesecatalysts allow the preparation of polyethylene in a good yield. Propylene in the presenceof the catalysts mentioned dimerizes and oligomerizes to trimers and tetramers at 25oCunder normal pressure. If the propylene pressure was increased to 7 atmospheres,CpTiCl2(OC6H4CH3/MAO catalyst at 25oC gave mixtures with different contents ofpropylene dimers, trimers and tetramers. At 70oC we obtained only propylene trimer.Using the catalysts with a -OC6H4Cl ligand we obtained atactic polymers with Mw182,000 g/mol (at 25oC and 100,000 g/mol (at 70oC. The superior activity of theCpTiCl2(OC6H4Cl/MAO catalyst used in polymerization of propylene prompted us tocheck its activity in polymerization of higher α-olefins (1-butene, 1-pentene, 1-hexeneand in co-polymerization of these olefins with ethylene. However, when homo-polymerization was carried out in the presence of this catalyst no polymers wereobtained. Gas chromatography analysis revealed the presence of dimers. The activity ofthe CpTiCl2(OC6H4Cl/MAO catalyst in the co-polymerization of ethylene with higher α-olefins is limited by the length of the co-monomer carbon chain. Hence, the highest catalyst activities were observed in co-polymerization of ethylene with propylene (here a lower pressure of the reagents and shorter reaction time were applied to obtain catalytic activity similar to that for other co-monomers. For other co-monomers the activity of the catalyst

  17. A solution processable fluorene-benzothiadiazole small molecule for n-type organic field-effect transistors

    Science.gov (United States)

    Mutkins, Karyn; Gui, Ke; Aljada, Muhsen; Schwenn, Paul E.; Namdas, Ebinazar B.; Burn, Paul L.; Meredith, Paul

    2011-04-01

    We report an n-type organic semiconductor [2-({7-(9,9-di-n-propyl-9H-fluoren-2-yl}benzo[c][1,2,5]thiadiazol-4-yl)methylene]malononitrile (herein referred to as K12) for use in organic field-effect transistors (OFETs). K12 can be processed by spin-coating from solution or by vacuum deposition, organizing into highly orientated microcrystalline structures at modest (75 °C) annealing temperatures. OFETs with n-octyltrichlorosilane or hexamethyldisilazane monolayers, or poly(propylene-co-1-butene) (PPCB) modified dielectric surfaces were prepared. The mobility, ON/OFF ratio, threshold voltage, and current hysteresis were found to be dependent on the thermal history of the film and surface onto which it was deposited. The highest OFET mobility achieved was 2.4×10-3 cm2/V s, for spin-coated films with a PPCB modified silicon dioxide dielectric.

  18. Characterization of the main automotive gasoline compounds by using gas chromatography; Caracterizacao dos principais componentes da gasolina automotiva atraves de cromatografia gasosa

    Energy Technology Data Exchange (ETDEWEB)

    Assis, Julio Cesar Rosa; Jaeger, Helena Valli; Almeida, Selmo Queiroz; Teixeira, Leonardo Sena Gomes; Pontes, Luiz Antonio Magalhaes; Vitor Sobrinho, Eledir; Guimaraes, Paulo Roberto Britto; Vianna, Regina Ferreira [Universidade Salvador - UNIFACS, Salvador, BA (Brazil). Dept. de Engenharia e Arquitetura]. E-mail: julio.assis@posgrad.unifacs.br

    2003-07-01

    Gasoline is composed of a number of hydrocarbons of varied structure and different functional groups, which have a marked influence on the final quality of the former. It is thus important to identify the main components of gasoline and how they influence some of its characteristics. This research work is concerned with the development of a technique, based on gas chromatography, for the separation and identification of more than 350 organic compounds likely to be present in gasoline. The study involved 50 gasoline samples collected at gas stations located in Salvador-Bahia (Brazil). The hydrocarbons identified were classified according to their main functional groups and compositions were obtained via a statistical treatment of the raw data. The results have shown that the gasoline used in Salvador has isopentane as the prevalent saturated compound, while m-xylene and methyl-butene are the most frequently found aromatic and olefin, respectively. (author)

  19. Highly Selective Conversion of Olefin Components in FCC Gasoline to Propylene in Monolithic Catalytic Reactors

    Institute of Scientific and Technical Information of China (English)

    Li Yang; Shao Qian; He Zhenfu; Tian Huiping; Long Jun

    2006-01-01

    The demand for propylene has been growing recently. The concentration of olefins in the gasoline is strictly limited by the related environmental regulations. The olefins contained in the gasoline used as the feed could be cracked into light olefins to slash the olefin concentration in the gasoline to yield more propylene at the same time. The monolithic catalyst washcoated on the modified ZSM-5 zeolite was used in the experiments. The effect of the temperature, the Si/A1 ratio in ZSM-5 and the addition of the rare earth elements on the selectivities and the yields of the light olefins were studied. The high yields of propylene and butene could be obtained under the experimental conditions of a higher temperature and Si/A1 ratio with the addition of rare earth elements.

  20. IMPACT PROPERTIES OF METALLOCENE-CATALYZED ETHYLENE-α-OLEFIN COPOLYMERS

    Institute of Scientific and Technical Information of China (English)

    Xu-rong Xu; Jun-ting Xua; Lin-xian Feng

    2002-01-01

    The impact properties of two selected metallocene-catalyzed ethylene-butene copolymers and one conventional copolymer were evaluated using Izod impact test. It is found that the metallocene-catalyzed copolymer shows superior impact properties. This result was explained on the basis of the more homogeneous inter-molecular composition distribution and narrower molecular weight distribution, which leads to more homogeneous morphology with fewer defects. Stepwise crystallization improves the impact properties, especially in the crack propagation process, to a large extent. This is due to the decrease of entanglements by stepwise crystallization, which is advantageous for the chain slip and shear. The polymer with heterogeneous intra-molecular composition distribution exhibits a more evident improvement of impact properties under stepwise crystallization.

  1. 烯烃歧化催化工艺进展%Advances in Catalytic Process of Olefin Metathesis

    Institute of Scientific and Technical Information of China (English)

    白尔铮

    2001-01-01

    The latest advances of catalytic process of olefins metathesiswere reviewed. The preparation of supported tungsten, supported molybdenum, and supported rhenium catalysts by Phillips Petroleum, IFP and Shell Co. were introduced. It was pointed out that we should put emphasis on developing the technology producing propylene and amylene from betene or producing ethylene and hexene from butene in view of the domestic conditions.%综述了烯烃歧化催化工艺的进展,介绍了PhillipsPetroleum、IFP、Shell公司制备载钨、载钼及载铼催化剂的方法。针对我国国情,指出应重点开发丁烯制丙烯和戊烯或丁烯制乙烯和己烯生产技术。

  2. Studies of the mechanism of the olefin metathesis reaction and the process of active site formation on photoreduced molybdenum-silicate catalysts. I. Mechanism of formation of molybdenum-carbene intermediates

    Energy Technology Data Exchange (ETDEWEB)

    Elev, I.V.; Shelimov, B.N.; Kazanskii, V.B.

    1987-10-01

    The products of the initial stages of the reaction of ethylene and propylene with Mo/sup 4 +/ ions in photoreduced molybdenum-silicate olefin metathesis catalysts have been studied by mass spectroscopy. The reaction of C/sub 2/H/sub 4/ with Mo/sup 4 +/ has been found to yield propylene, whereas interaction of C/sub 3/H/sub 6/ with Mo/sup 4 +/ gives a superequilibrium concentration of butenes and a small amount of pentenes. A significant kinetic isotope effect for the metathesis reaction was observed upon substitution of C/sub 3/H/sub 6/ by C/sub 3/D/sub 6/. The results can be interpreted in terms of a stepwise mechanism involving carbene intermediates, which are formed via isomerization of surface-bound ..pi..-complexes of olefins with Mo/sup 4 +/ ions as a result of intramolecular 1,2-H atom transfer.

  3. Kinetic Selectivity of Olefin Metathesis Catalysts Bearing Cyclic (Alkyl)(Amino)Carbenes

    Science.gov (United States)

    Anderson, Donde R.; Ung, Thay; Mkrtumyan, Garik; Bertrand, Guy; Grubbs, Robert H.; Schrodi, Yann

    2008-01-01

    The evaluation of ruthenium olefin metathesis catalysts 4–6 bearing cyclic (alkyl)(amino)carbenes (CAACs) in the cross-metathesis of cis-1,4-diacetoxy-2-butene (7) with allylbenzene (8) and the ethenolysis of methyl oleate (11) is reported. Relative to most NHC-substituted complexes, CAAC-substituted catalysts exhibit lower E/Z ratios (3:1 at 70% conversion) in the cross-metathesis of 7 and 8. Additionally, complexes 4–6 demonstrate good selectivity for the formation of terminal olefins versus internal olefins in the ethenolysis of 11. Indeed, complex 6 achieved 35 000 TONs, the highest recorded to date. CAAC-substituted complexes exhibit markedly different kinetic selectivity than most NHC-substituted complexes. PMID:18584055

  4. Substantially isotactic, linear, alternating copolymers of carbon monoxide and an olefin

    Science.gov (United States)

    Sen, Ayusman; Jiang, Zhaozhong

    1996-01-01

    The compound, [Pd(Me-DUPHOS)(MeCN).sub.2 ](BF.sub.4).sub.2, [Me-DUPHOS: 1,2-bis(2,5-dimethylphospholano)benzene] is an effective catalyst for the highly enantioselective, alternating copolymerization of olefins, such as aliphatic .alpha.-olefins, with carbon monoxide to form optically active, isotactic polymers which can serve as excellent starting materials for the synthesis of other classes of chiral polymers. For example, the complete reduction of a propylene-carbon monoxide copolymer resulted in the formation of a novel, optically active poly(1,4-alcohol). Also, the previously described catalyst is a catalyst for the novel alternating isomerization cooligomerization of 2-butene with carbon monoxide to form optically active, isotactic poly(1,5-ketone)

  5. Development of segmented polyurethane elastomers with low iodine content exhibiting radiopacity and blood compatibility

    International Nuclear Information System (INIS)

    Biofunctionally active and inherently radiopaque polymers are the emerging need for biomedical applications. Novel segmented polyurethane elastomer with inherent radiopacity was prepared using aliphatic chain extender 2,3-diiodo-2-butene-1,4-diol, polyol polytetramethylene glycol and 4,4'-methylenebis(phenyl isocyanate) (MDI) for blood compatible applications. Aliphatic polyurethane was also prepared using hexamethylene diisocyanate for comparison. X-ray analysis of the polyurethanes revealed good radiopacity even at a relatively low concentration of 3% iodine in aromatic polyurethane and 10% in aliphatic polyurethane. The polyurethanes also possessed excellent thermal stability. MDI-based polyurethane showed considerably higher tensile strength than the analogous HDI-based polyurethane. MDI-based aromatic polyurethane exhibited a dynamic surface morphology in aqueous medium, resulting in the segregation of hydrophilic domains which was more conducive to anti-thrombogenic properties. The polyurethane was cytocompatible with L929 fibroblast cells, non-hemolytic, and possessed good blood compatibility.

  6. Synthesis and characterization of free-isocyanate polyurethane as renewable coating materials

    Science.gov (United States)

    Saputra, O. A.; Apriany, K.; Putri, F. R.; Firdaus, M.

    2016-02-01

    Green synthesis of diethyl ethane-1,2-diyldicarbamate (M1) as starting dimer of free-isocyanate polyurethane from an excess of diethyl carbonate and ethylene diamine catalyzed by TBD (1,5,7-triazabicyclo-[4,4,0]dec-5-ene) at 80 °C for 4 hours has been carried out. The product has high yield and purity up to 92% and 99,18%, respectively. The product was obtained in the form of rod-shaped white crystals and characterized with 1H-NMR, 13C-NMR and FTIR spectroscopy. Polyurethane (P1) has successfully synthesized via polycondensation methods by reacting of M1 with cis-2-butene-1,4-diol. This reaction also catalyzed by TBD organo catalyst. P1 chemical structure has been confirmed using 1H-NMR and FTIR techniques.

  7. Synthesis and Antimicrobial Evaluation of Some Pyrazole Derivatives

    Directory of Open Access Journals (Sweden)

    Nagwa Mohamed Mahrous Hamada

    2012-04-01

    Full Text Available Reaction of a series of (E-3-phenyl-4-(p-substituted phenyl-3-buten-2-ones with p-sulfamylphenyl hydrazine in glacial acetic acid gave the corresponding hydrazones, subsequent treatment of which with 30% HCl afforded pyrazole-1-sulphonamides. On the other hand, refluxing of chalcones with either thiosemicarbazide or isonicotinic acid hydrazide in ethanol containing a few drops of acetic acid gave pyrazoline-1-thiocarboxamides and isonicotinoyl pyrazolines, respectively. The structures of the synthesized compounds were determined on the basis of their elemental analyses and spectroscopic data. The antimicrobial activity of the newly isolated heterocyclic compounds was evaluated against Gram-positive, Gram-negative bacteria and fungi. Most of the compounds showed a moderate degree of potent antimicrobial activity.

  8. Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines.

    Science.gov (United States)

    Yan, Tao; Barta, Katalin

    2016-09-01

    Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily available alcohol substrates have been recently established; however, these approaches rely on the use of noble metals such as ruthenium or iridium. Here, we report on the direct synthesis of pyrroles using a catalyst based on the earth-abundant and inexpensive iron. The method uses 2-butyne-1,4-diol or 2-butene-1,4-diol that can be directly coupled with anilines, benzyl amines, and aliphatic amines to obtain a variety of N-substituted pyrroles in moderate-to-excellent isolated yields.

  9. Sustainable Pathways to Pyrroles through Iron-Catalyzed N-Heterocyclization from Unsaturated Diols and Primary Amines.

    Science.gov (United States)

    Yan, Tao; Barta, Katalin

    2016-09-01

    Pyrroles are prominent scaffolds in pharmaceutically active compounds and play an important role in medicinal chemistry. Therefore, the development of new, atom-economic, and sustainable catalytic strategies to obtain these moieties is highly desired. Direct catalytic pathways that utilize readily available alcohol substrates have been recently established; however, these approaches rely on the use of noble metals such as ruthenium or iridium. Here, we report on the direct synthesis of pyrroles using a catalyst based on the earth-abundant and inexpensive iron. The method uses 2-butyne-1,4-diol or 2-butene-1,4-diol that can be directly coupled with anilines, benzyl amines, and aliphatic amines to obtain a variety of N-substituted pyrroles in moderate-to-excellent isolated yields. PMID:27493031

  10. Roaming dynamics in radical addition-elimination reactions

    Science.gov (United States)

    Joalland, Baptiste; Shi, Yuanyuan; Kamasah, Alexander; Suits, Arthur G.; Mebel, Alexander M.

    2014-06-01

    Radical addition-elimination reactions are a major pathway for transformation of unsaturated hydrocarbons. In the gas phase, these reactions involve formation of a transient strongly bound intermediate. However, the detailed mechanism and dynamics for these reactions remain unclear. Here we show, for reaction of chlorine atoms with butenes, that the Cl addition-HCl elimination pathway occurs from an abstraction-like Cl-H-C geometry rather than a conventional three-centre or four-centre transition state. Furthermore, access to this geometry is attained by roaming excursions of the Cl atom from the initially formed adduct. In effect, the alkene π cloud serves to capture the Cl atom and hold it, allowing many subsequent opportunities for the energized intermediate to find a suitable approach to the abstraction geometry. These bimolecular roaming reactions are closely related to the roaming radical dynamics recently discovered to play an important role in unimolecular reactions.

  11. Study and Design of Waste Heat Recovery using Organic Rankine Cycle

    Directory of Open Access Journals (Sweden)

    Seyed Saied Homami

    2016-03-01

    Full Text Available Existing energy crisis in the world has diverted human perspective to the optimum usage of the available energy resources. One of these solutions is waste heat recovery systems[1]. Simultaneous production of fresh water, power and cooling from waste heat improves energy efficiency in industrial applications which could be operated by organic Rankine cycles. In this article, cogeneration of electricity and heat (CHP in the petrochemical industry, textile and paper production has been reviewed and the usage of aforesaid cycle in these industries is determined. Designing organic Rankine cycle (with operating fluid organic trans-butene and taking advantage of the excess low pressure steam, a strategy for producing three valuable products of fresh water, power and refrigeration in the petrochemical industries has been offered. Simultaneous production of 10,000 kg/hr fresh water, 1533 kw power and access to the lower temperatures of about 226 K and 260 K were resulted.

  12. New Catalytic Materials for Meeting the Challenge of Clean Gasoline & Diesel Fuel Production

    Institute of Scientific and Technical Information of China (English)

    Zong Baoning; Min Enze; He Mingyuan; Li Dadong

    2000-01-01

    New catalytic materials, which may bring important improvement or technical breakthrough to the petroleum refining technology for producing reformulated gasoline and low sulfur and aromatics diesel fuel, are discussed. For the purpose of producing high octane number gasoline and light olefins for etherification and alkylation processes, major improvements are achieved by the use of high reactivity-stability MFI type ZRP and low cost beta zeolites. A solid P-W heteropolyacid supported on SiO2 for replacing currently used HF and H2SO4 in alkylation process of isobutane with butenes, is under the pilot trial. For the production of low sulfur and aromatics diesel fuel, high surface area supported metallic nitrides are under extensive studies.

  13. Synthesis of substrates for periodate-coupled assay of phospholipases C and sphingomyelinases.

    Science.gov (United States)

    Larsen, Kira Løw; Andersen, Rokhsana J; Brask, Jesper

    2016-09-01

    A series of 4-nitrophenyl (pNP) and 4-methylumbelliferyl (4MU) substrate analogues of phosphatidyl choline (PC) and phosphatidic acid (PA) were synthesized from 4-bromo-1-butene by ether formation, olefin epoxidation and ring opening with the phosphate head group. The pNP PC analogue, 4-(4-nitrophenoxy)-2-hydroxy-butyl-1-phosphoryl choline (1) was evaluated in assays of fungal sphingomyelinases, also displaying phospholipase C activity. Reactions were terminated with a periodate-containing stop solution, leading to liberation of pNP, quantified spectrophotometrically in an end-point measurement. A kinetic evaluation of sphingomyelinases from Kionochaeta sp. and Penicillium emersonii showed relatively high KM and low kcat values for this substrate, limiting its practical applicability in assays with low sphingomyelinase concentrations. PMID:27444331

  14. (2Z-3-(4-Chloroanilino-1-(5-hydroxy-3-methyl-1-phenyl-1H-pyrazol-4-ylbut-2-en-1-one

    Directory of Open Access Journals (Sweden)

    Abdullah M. Asiri

    2011-08-01

    Full Text Available With the exception of the terminal benzene rings, the atoms in the title compound, C20H18ClN3O2, are approximately coplanar (r.m.s. deviation = 0.0495 Å. The benzene/chlorobenzene rings form dihedral angles of 3.02 (4 and 41.59 (5°, respectively, with this plane. The hydroxy, amino and carbonyl groups all lie to the same side of the molecule, enabling the formation of intramolecular O—H...O and N—H...O hydrogen bonds that close S(6 rings. The configuration about the 2-butene bond is Z. Supramolecular chains mediated by C—H...Cl interactions and aligned along the c axis are found in the crystal packing. These assemble into layers that are connected by weak π–π interactions between centrosymmetrically related chlorobenzene rings [3.8156 (9 Å].

  15. 利用MTO工艺副产的混合C4生产2-丙基庚醇%Utilizing MTO Plant's By-Product Mixed C4 to Produce 2-Propyl-Heptanol

    Institute of Scientific and Technical Information of China (English)

    涂万辉; 李杰

    2012-01-01

    MTO工艺副产的混合C4中正丁烯含量在70%以上,可通过低压羰基合成技术生产2-丙基庚醇。2-丙基庚醇主要用于合成新型增塑剂DPHP。得益于DPHP安全、增塑性好、成本低的优势,2-丙基庚醇有着广阔的市场前景。%Butene content in mixed C4 by-produced during MTO production is over 70%, which can produce 2-propyl-heptanol with LP oxo-synthesis technology. The product is mainly applied for synthesizing plasticizer DPHP which has broad market prospect because of its good safety, plastifing behavious and low cost.

  16. Three-Dimensional Conformation of Folded Polymers in Single Crystals

    Science.gov (United States)

    Hong, You-lee; Yuan, Shichen; Li, Zhen; Ke, Yutian; Nozaki, Koji; Miyoshi, Toshikazu

    2015-10-01

    The chain-folding mechanism and structure of semicrystalline polymers have long been controversial. Solid-state NMR was applied to determine the chain trajectory of 13C CH3 -labeled isotactic poly(1-butene) (i PB 1 ) in form III chiral single crystals blended with nonlabeled i PB 1 crystallized in dilute solutions under low supercooling. An advanced 13C - 13C double-quantum NMR technique probing the spatial proximity pattern of labeled 13C nuclei revealed that the chains adopt a three-dimensional (3D) conformation in single crystals. The determined results indicate a two-step crystallization process of (i) cluster formation via self-folding in the precrystallization stage and (ii) deposition of the nanoclusters as a building block at the growth front in single crystals.

  17. Experimental study of the structure of rich premixed 1,3-butadiene/CH4/O2/Ar flame

    CERN Document Server

    Gueniche, Hadj-Ali; Fournet, René; Battin-Leclerc, Frédérique

    2006-01-01

    The structure of a laminar rich premixed 1,3-C4H6/CH4/O2/Ar flame have been investigated. 1,3-Butadiene, methane, oxygen and argon mole fractions are 0.033; 0.2073; 0.3315, and 0.4280, respectively, for an equivalent ratio of 1.80. The flame has been stabilized on a burner at a pressure of 6.7 kPa (50 Torr). The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz probe. Quantified species included carbon monoxide and dioxide, methane, oxygen, hydrogen, ethane, ethylene, acetylene, propyne, allene, propene, cyclopropane, 1,3-butadiene, butenes, 1-butyne, vinylacetylene, diacetylene, C5 compounds, benzene, and toluene. The temperature was measured thanks to a thermocouple in PtRh (6%)-PtRh (30%) settled inside the enclosure and ranged from 900 K close to the burner up to 2100 K.

  18. Synthesis of Ni-SiO2/silicalite-1 core-shell micromembrane reactors and their reaction/diffusion performance

    KAUST Repository

    Khan, Easir A.

    2010-12-15

    Core-shell micromembrane reactors are a novel class of materials where a catalyst and a shape-selective membrane are synergistically housed in a single particle. In this work, we report the synthesis of micrometer -sized core-shell particles containing a catalyst core and a thin permselective zeolite shell and their application as a micromembrane reactor for the selective hydrogenation of the 1-hexene and 3,3-dimethyl-1-butene isomers. The bare catalyst, which is made from porous silica loaded with catalytically active nickel, showed no reactant selectivity between hexene isomers, but the core-shell particles showed high selectivities up to 300 for a 1-hexene conversion of 90%. © 2010 American Chemical Society.

  19. Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland

    Directory of Open Access Journals (Sweden)

    M. Claeys

    2005-05-01

    Full Text Available Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol, 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis and trans and 3-methyl-2,3,4-trihydroxy-1-butene have been detected in boreal forest PM1 aerosols collected at Hyytiälä, southern Finland, during a 2004 summer period, at significant atmospheric concentrations (in total 51 ng m-3 in summer versus 0.46 ng m-3 in fall. On the basis of these results, it can be concluded that photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol formation during summer in this conifer forest ecosystem. In addition to isoprene oxidation products, malic acid, which can be regarded as an end-oxidation product of unsaturated fatty acids, was also detected at high concentrations during the summer period (46 ng m-3 in summer versus 5.2 ng m-3 in fall, while levoglucosan, originating from biomass burning, became relatively more important during the fall period (29 ng m-3 in fall versus 10 ng m-3 in summer. Pinic acid, a major photo-oxidation product of α-pinene in laboratory experiments, could only be detected at trace levels in the summer PM1 aerosol samples from Hyytiälä, suggesting that further oxidation of pinic acid occurs and/or that different oxidation pathways are followed. We hypothesize that photo-oxidation of isoprene may participate in the early stages of new particle formation, a phenomenon which has been well documented in the boreal forest environment.

  20. Observation of 2-methyltetrols and related photo-oxidation products of isoprene in boreal forest aerosols from Hyytiälä, Finland

    Directory of Open Access Journals (Sweden)

    I. Kourtchev

    2005-01-01

    Full Text Available Oxidation products of isoprene including 2-methyltetrols (2-methylthreitol and 2-methylerythritol, 2-methylglyceric acid and triol derivatives of isoprene (2-methyl-1,3,4-trihydroxy-1-butene (cis and trans and 3-methyl-2,3,4-trihydroxy-1-butene have been detected in boreal forest PM1 aerosols collected at Hyytiälä, southern Finland, during a 2004 summer period, at significant atmospheric concentrations (in total 51 ng m−3 in summer versus 0.46 ng m−3 in fall. On the basis of these results, it can be concluded that photo-oxidation of isoprene is an important atmospheric chemistry process that contributes to secondary organic aerosol formation during summer in this conifer forest ecosystem. In addition to isoprene oxidation products, malic acid, which can be regarded as an intermediate in the oxidation of unsaturated fatty acids, was also detected at high concentrations during the summer period (46 ng m−3 in summer versus 5.2 ng m−3 in fall, while levoglucosan, originating from biomass burning, became relatively more important during the fall period (29 ng m−3 in fall versus 10 ng m−3 in summer. Pinic acid, a major photo-oxidation product of α-pinene in laboratory experiments, could only be detected at trace levels in the summer samples, suggesting that further oxidation of pinic acid occurs and/or that different oxidation pathways are followed. We hypothesize that photo-oxidation of isoprene may participate in the early stages of new particle formation, a phenomenon which has been well documented in the boreal forest environment.

  1. Polar organic marker compounds in atmospheric aerosols: Determination, time series, size distributions and sources

    Science.gov (United States)

    Kourtchev, Ivan

    Terrestrial vegetation releases substantial amounts of reactive volatile organic compounds (VOCs; e.g., isoprene, monoterpenes) into the atmosphere. The VOCs can be rapidly photooxidized under conditions of high solar radiation, yielding products that can participate in new particle formation and growth processes above forests. This thesis focuses on the characterization, identification and quantification of oxidation products of biogenic VOC (BVOCs) as well as other species (tracer compounds) that provide information on aerosol sources and source processes. Atmospheric aerosols from various forested sites (i.e., Hyytiala, southern Finland; Rondonia, Brazil; K-Puszta, Hungary and Julich, Germany) were analyzed with Gas Chromotography/Mass Spectrometry (GC/MS) using analytical procedure that targets polar organic compounds. The study demonstrated that isoprene (i.e., 2-methyerythritol, 2-methylthreitol, 2-methylglyceric acid and C5-alkene triols (2-methyl-1,3,4-trihydroxy-l-butene (cis and trans) and 3 methyl-2,3,4-trihydroxy-1-butene)) and monoterpene (pinic acid, norpinic acid, 3-hydroxyglutaric acid and 3-methyl-1,2,3-butanetricarboxylic acid) oxidation products were present in substantial concentrations in atmospheric aerosols suggesting that oxidation of BVOC from the vegetation is an important process in all studied sites. On the other hand, presence of levoglucosan, biomass burning marker, especially in Amazonian rain forest site at Rondonia, Brazil, pointed that all sites were affected by anthropogenic activities, namely biomass burning. Other identified compounds included plyols, arabitol, mannitol and erythritol, which are marker compounds for fungal spores and monosacharides, glucose and fructose, markers for plant polens. Temporal variations as well as mass size distributions of the detected species confirmed the possible formation mechanisms of marker compounds.

  2. Field responses of the Asian larch bark beetle, Ips subelongatus, to potential aggregation pheromone components: disparity between two populations in northeastern China

    Institute of Scientific and Technical Information of China (English)

    Li-Wen Song; Qing-He Zhang; Yue-Qu Chen; Tong-Tong Zuo; Bing-Zhong Ren

    2011-01-01

    Behavioral responses of the Asian larch bark beetle, Ips subelongatus Motsch. to three potential aggregation pheromone components, ipsenol (racemic or [-]-enantiomer), ipsdienol (racemic or [+]-enantiomer) and 3-methyl-3-buten-1 -ol, were tested using partial or full factorial experimental designs in two provinces (Inner Mongolia and Jilin) of northeastern China. Our field bioassays in Inner Mongolia (Larix principis- rupprechtii Mayr. plantation) clearly showed that ipsenol, either racemic or 97%-(-)-enantiomer, was the only compound that significantly attracted both sexes of I. subelongatus, while all other compounds (singly or in combinations) were unattractive. There were no two- or three-way synergistic interactions. However, in Jilin Province (L. gmelini [Rupr.] Rupr. Plantation), all the individual compounds tested were inactive, except a very weak activity by 97%-(-)-ipsenol in 2004 when the beetle population was very high. While a combination of ipsenol and ipsdienol (racemates or enantiomerically pure natural enantiomers) showed a significant attraction for both sexes of I. subelongatus, indicating a two-way synergistic interaction between these two major components, addition of 3-methyl-3-buten-l-ol to these active binary blend(s) did not have any effects on trap catches, suggesting that ipsenol and ipsdienol are the synergistic aggregation pheromone components of I. subelongatus in Jilin Province. It seems that 97%-(-)-ipsenol in Inner Mongolia or the binary blend of 97%-(-)-ipsenol and 97%-(+)-ipsdienol in Jilin Province are superior to their corresponding racemates, which might be due either to weak inhibitory effects of the antipode enantiomers or to reduced release rates of the active natural enantiomers) in the racemate(s). Our current bioassay results suggest that there is a strong geographical variation in aggregation pheromone response of I. subelongatus in northeastern China. Future research on the pheromone production and response of I

  3. Generation, characterization, and reactivity of the transition metal-o-benzne analog of pyrazine (Fe{sup +}-2,3-didehydropyrazine) in the gas phase: An experimental and theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.; Jacobson, D.B.; Freiser, B.S. [Purdue Univ., West Lafayette, IN (United States). H.C. Brown Lab. of Chemistry

    1999-04-26

    Fe{sup +}-2,3-didehydropyrazine (2) has been generated and its reactivity with simple olefins and alkynes studied by using Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. 2, which is prepared by dehalogenation of chloropyrazine by Fe{sup +}, undergoes a simple adduct formation (no ligand coupling) with ethene and ethene-d{sub 4}. Ethyne also yields adduct formation; however, ligand coupling has clearly occurred in this reaction. Interestingly, reactions with propene and isobutene yield the same products with similar product distributions. Again, ligand coupling is involved and a metal-centered mechanism featuring activation of the allylic carbon-hydrogen bonds is proposed. Propyne, allene, 1-butene, and cis-2-butene yield a variety of products with 2. However, 2 yields exclusive dehydrogenation with 1,3-butadiene to generate FeC{sub 8}H{sub 6}N{sub 2}{sup +}. CID results suggest that this FeC{sub 8}H{sub 6}N{sub 2}{sup +} ion consists of quinoxaline bound to Fe{sup +}. Ligand displacement reactions yield a bond dissociation energy of 47 {+-} 5 kcal/mol for D{degree}(Fe{sup +}-quinoxaline). FeC{sub 4}H{sub 2}N{sub 2}{sup +} ion (2) has also been investigated theoretically. Density functional calculations predicted that the ground state of 2,3-didehydropyrazine is the triplet state, with the singlet state being 9.9 kcal/mol higher than the triplet state. 2 has C{sub 2{nu}} symmetry with the metal center coplanar with the 2,3-didehydropyrazine ring. 2 has a sextet ground state with doublet and quartet states 4.9 and 6.8 kcal/mol higher, respectively. The bond dissociation energy D{degree}(Fe{sup +}-C{sub 4}H{sub 2}N{sub 2}) for the sextet ground state is computed to be 87 {+-} 10 kcal/mol.

  4. Application of gas chromatography analysis to quality control of residual organic solvents in clopidogrel bisulphate

    Directory of Open Access Journals (Sweden)

    Pavlović Aleksandar D.

    2014-01-01

    Full Text Available A direct-injection, split-mode capillary gas chromatographic procedure with a flame ionization detection is developed for the analysis of eight solvents used in the synthesis and purification of an anti-thrombotic drug clopidogrel bisulphate. The solvents analyzed were methanol, acetone, dichloromethane (DCM, 2-butanol, cyclohexane, toluene, acetic acid and N, N-dimethyl formamide (DMF. In addition, as a result of dehydration of 2-butanol during drying process, in clopidogrel bisulphate samples, significant amounts of 2-butanol dehydration products (1-butene, cis and trans isomers of 2-butene, 2,2'-oxydibutane and 1-(1-methylpropoxybutane may be detected. The content of each of these volatile products can be evaluated using the same gas-chromatographic method, with quantification based on the response factor established for the chromatographic peak of 2-butanol. For each solvent used in the process of clopidogrel bisulphate preparation, the procedure is validated for selectivity, linearity, recovery, precision, robustness, quantitation limit, and detection limit. All eight solvents plus five 2-butanol degradation products are fully separated. System suitability test is validated, and requirements are set. Based on a large number of result sets, retrospectively, from many different batches analyzed, conclusions were made about process variations and reliability and a lack of consistency was identified in the quality of the active substance from a particular producer source. Multivariate analysis was used as statistical technique to classify samples. From the analyzed set of 11 solvents, 6 of them were preselected based upon their occurrence in the samples and both Principal Component Analysis (PCA and Hierarchical Cluster Analysis (HCA were performed.

  5. Muscodor albus E-6, an endophyte of Guazuma ulmifolia making volatile antibiotics: isolation, characterization and experimental establishment in the host plant.

    Science.gov (United States)

    Strobel, Gary A; Kluck, Katreena; Hess, Wilford M; Sears, Joe; Ezra, David; Vargas, Percy N

    2007-08-01

    Muscodor albus is an endophytic fungus, represented by a number of isolates from tropical tree and vine species in several of the world's rainforests, that produces volatile organic compounds (VOCs) with antibiotic activity. A new isolate, E-6, of this organism, with unusual biochemical and biological properties, has been obtained from the branches of a mature Guazuma ulmifolia (Sterculiaceae) tree growing in a dry tropical forest in SW Ecuador. This unique organism produces many VOCs not previously observed in other M. albus isolates, including butanoic acid, 2-methyl-; butanoic acid, 3-methyl-; 2-butenal, 2-methyl-; butanoic acid, 3-methylbutyl ester; 3-buten-1-ol, 3-methyl; guaiol; 1-octene, 3-ethyl-; formamide, N-(1-methylpropyl); and certain azulene and naphthalene derivatives. Some compounds usually seen in other M. albus isolates also appeared in the VOCs of isolate E-6, including caryophyllene; phenylethyl alcohol; acetic acid, 2-phenylethyl ester; bulnesene; and various propanoic acid, 2-methyl- derivatives. The biological activity of the VOCs of E-6 appears different from the original isolate of this fungus, CZ-620, since a Gram-positive bacterium was killed, and Sclerotinia sclerotiorum and Rhizoctonia solani were not. Scanning electron micrographs of the mycelium of isolate E-6 showed substantial intertwining of the hyphal strands. These strands seemed to be held together by an extracellular matrix accounting for the strong mat-like nature of the mycelium, which easily lifts off the agar surface upon transfer, unlike any other isolate of this fungus. The ITS-5.8S rDNA partial sequence data showed 99 % similarity to the original M. albus strain CZ-620. For the first time, successful establishment of M. albus into its natural host, followed by recovery of the fungus, was accomplished in seedlings of G. ulmifolia. Overall, isolates of M. albus, including E-6, have chemical, biological and structural characteristics that make them potentially useful in

  6. Calculational and Experimental Investigations of the Pressure Effects on Radical - Radical Cross Combinations Reactions: C2H5 + C2H3

    Science.gov (United States)

    Fahr, Askar; Halpern, Joshua B.; Tardy, Dwight C.

    2007-01-01

    Pressure-dependent product yields have been experimentally determined for the cross-radical reaction C2H5 + C2H3. These results have been extended by calculations. It is shown that the chemically activated combination adduct, 1-C4H8*, is either stabilized by bimolecular collisions or subject to a variety of unimolecular reactions including cyclizations and decompositions. Therefore the "apparent" combination/disproportionation ratio exhibits a complex pressure dependence. The experimental studies were performed at 298 K and at selected pressures between about 4 Torr (0.5 kPa) and 760 Torr (101 kPa). Ethyl and vinyl radicals were simultaneously produced by 193 nm excimer laser photolysis of C2H5COC2H3 or photolysis of C2H3Br and C2H5COC2H5. Gas chromatograph/mass spectrometry/flame ionization detection (GC/MS/FID) were used to identify and quantify the final reaction products. The major combination reactions at pressures between 500 (66.5 kPa) and 760 Torr are (1c) C2H5 + C2H3 yields 1-butene, (2c) C2H5 + C2H5 yields n-butane, and (3c) C2H3 + C2H3 yields 1,3-butadiene. The major products of the disproportionation reactions are ethane, ethylene, and acetylene. At moderate and lower pressures, secondary products, including propene, propane, isobutene, 2-butene (cis and trans), 1-pentene, 1,4-pentadiene, and 1,5-hexadiene are also observed. Two isomers of C4H6, cyclobutene and/or 1,2-butadiene, were also among the likely products. The pressure-dependent yield of the cross-combination product, 1-butene, was compared to the yield of n-butane, the combination product of reaction (2c), which was found to be independent of pressure over the range of this study. The [ 1-C4H8]/[C4H10] ratio was reduced from approx.1.2 at 760 Torr (101 kPa) to approx.0.5 at 100 Torr (13.3 kPa) and approx.0.1 at pressures lower than about 5 Torr (approx.0.7 kPa). Electronic structure and RRKM calculations were used to simulate both unimolecular and bimolecular processes. The relative importance

  7. Theoretical calculations of hyperfine coupling constants for muoniated butyl radicals.

    Science.gov (United States)

    Chen, Ya Kun; Fleming, Donald G; Wang, Yan Alexander

    2011-04-01

    The hyperfine coupling constants (HFCCs) of all the butyl radicals that can be produced by muonium (Mu) addition to butene isomers (1- and 2-butene and isobutene) have been calculated, to compare with the experimental results for the muon and proton HFFCs for these radicals reported in paper II (Fleming, D. G.; et al. J. Phys. Chem. A 2011, 10.1021/jp109676b) that follows. The equilibrium geometries and HFCCs of these muoniated butyl radicals as well as their unsubstituted isotopomers were treated at both the spin-unrestricted MP2/EPR-III and B3LYP/EPR-III levels of theory. Comparisons with calculations carried out for the EPR-II basis set have also been made. All calculations were carried out in vacuo at 0 K only. A C-Mu bond elongation scheme that lengthens the equilibrium C-H bond by a factor of 1.076, on the basis of recent quantum calculations of the muon HFCCs of the ethyl radical, has been exploited to determine the vibrationally corrected muon HFCCs. The sensitivity of the results to small variations around this scale factor was also investigated. The computational methodology employed was "benchmarked" in comparisons with the ethyl radical, both with higher level calculations and with experiment. For the β-HFCCs of interest, compared to B3LYP, the MP2 calculations agree better with higher level theories and with experiment in the case of the eclipsed C-Mu bond and are generally deemed to be more reliable in predicting the equilibrium conformations and muon HFCCs near 0 K, in the absence of environmental effects. In some cases though, the experimental results in paper II demonstrate that environmental effects enhance the muon HFCC in the solid phase, where much better agreement with the experimental muon HFCCs near 0 K is found from B3LYP than from MP2. This seemingly better level of agreement is probably fortuitous, due to error cancellations in the DFT calculations, which appear to mimic these environmental effects. For the staggered proton HFCCs of the

  8. Kinetic modeling of mechanisms of industrially important organic reactions in gas and liquid phase

    Energy Technology Data Exchange (ETDEWEB)

    Vahteristo, K.

    2010-07-01

    This dissertation is based on 5 articles which deal with reaction mechanisms of the following selected industrially important organic reactions: 1. dehydrocyclization of n-butylbenzene to produce naphthalene, 2. dehydrocyclization of 1-(p-tolyl)-2-methylbutane (MB) to produce 2,6-dimethylnaphthalene, 3. esterification of neopentyl glycol (NPG) with different carboxylic acids to produce monoesters, 4. skeletal isomerization of 1-pentene to produce 2-methyl-1-butene and 2-methyl-2-butene. The results of initial- and integral-rate experiments of n-butylbenzene dehydrocyclization over selfmade chromia/alumina catalyst were applied when investigating reaction 2. Reaction 2 was performed using commercial chromia/alumina of different acidity, platina on silica and vanadium/calcium/alumina as catalysts. On all catalysts used for the dehydrocyclization, major reactions were fragmentation of MB and 1-(p-tolyl)-2-methylbutenes (MBes), dehydrogenation of MB, double bond transfer, hydrogenation and 1,6-cyclization of MBes. Minor reactions were 1,5-cyclization of MBes and methyl group fragmentation of 1,6- cyclization products. Esterification reactions of NPG were performed using three different carboxylic acids: propionic, isobutyric and 2-ethylhexanoic acid. Commercial heterogeneous gellular (Dowex 50WX2), macroreticular (Amberlyst 15) type resins and homogeneous para-toluene sulfonic acid were used as catalysts. At first NPG reacted with carboxylic acids to form corresponding monoester and water. Then monoester esterified with carboxylic acid to form corresponding diester. In disproportionation reaction two monoester molecules formed NPG and corresponding diester. All these three reactions can attain equilibrium. Concerning esterification, water was removed from the reactor in order to prevent backward reaction. Skeletal isomerization experiments of 1-pentene were performed over HZSM-22 catalyst. Isomerization reactions of three different kind were detected: double bond, cis

  9. Gas-phase chemistry of Sc(CH{sub 3}){sub 2}{sup +} with alkenes: Activation of allylic C-H bonds by a d{sup 0} system and the migratory insertion of C=C bonds into Sc{sup +}-CH{sub 3} bonds

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Yongqing; Hill, Y.D.; Freiser, B.S. [Purdue Univ., West Lafayette, IN (United States)] [and others

    1992-11-04

    The gas-phase chemistry of Sc(CH{sub 3}){sub 2}{sup +} with alkenes was studied by Fourier transform mass spectrometry. The metal center on Sc(CH{sub 3}){sub 2}{sup +} is d{sup 0}, providing an opportunity to study alternative mechanisms of C-C or C-H activation other than the most common one involving oxidative addition. The elimination of H{sub 2} is observed in the reaction of Sc(CH{sub 3}){sub 2}{sup +} with ethylene, and the product ScC{sub 4}H{sub 8}{sup +} and ScC{sub 6}H{sub 10}{sup +} ions have a metal(methyl)(allyl) and metal-bisallyl structure, respectively, consistent with a proposed reaction mechanism involving the consecutive migratory insertion of ethylenes into the scandium-methyl bonds. In addition, theoretical calculations indicate that the metal(methyl)(allyl) structure is between 10 and 20 kcal/mol more stable than the metal(1-butene) isomer. Sc(CH{sub 3}){sub 2}{sup +} reacts with propene to form predominantly ScC{sub 4}H{sub 8}{sup +} by loss of CH{sub 4}, with minor amounts of ScC{sub 3}H{sub 4}{sup +} and ScC{sub 4}H{sub 6}{sup +} also observed. ScC{sub 4}H{sub 6}{sup +} is formed as either the exclusive or the predominant product ion in the reactions of Sc(CH{sub 3}){sub 2}{sup +} with butenes. Sc(CH{sub 3}){sub 2} reacts with cyclopentene to form predominantly ScC{sub 6}H{sub 8}{sup +} by losing CH{sub 4} and H{sub 2}. Isotope labeling studies with Sc(CD{sub 3}){sub 2}{sup +} and other structure studies indicate that all of the alkenes studied, with the exception of ethylene, react with Sc(CH{sub 3}){sub 2}{sup +} via a multicentered {sigma}-bond metathesis mechanism to activate allylic C-H bonds. Finally, the dehydrogenation reactions of Sc{sup +} with n-butane and neopentane were revisited, and a new mechanism is proposed for such chemistry in light of the new results from this study. 34 refs., 5 figs., 2 tabs.

  10. Pathway and Surface Mechanism Studies of 1,3-butadiene Selective Oxidation Over Vanadium-Molybdenum-Oxygen Catalysts

    Energy Technology Data Exchange (ETDEWEB)

    William David Schroeder

    2002-05-27

    The partial oxidation of 1,3-butadiene has been investigated over VMoO catalysts synthesized by sol-gel techniques. Surface areas were 9-14 m{sup 2}/g, and compositions were within the solid solution regime, i.e. below 15.0 mol % MoO{sub 3}/(MoO{sub 3} + V{sub 2}O{sub 5}). Laser Raman Spectroscopy and XRD data indicated that solid solutions were formed, and pre- and post-reaction XPS data indicated that catalyst surfaces contained some V{sup +4} and were further reduced in 1,3-butadiene oxidation. A reaction pathway for 1,3-butadiene partial oxidation to maleic anhydride was shown to involve intermediates such as 3,4-epoxy-1-butene, crotonaldehyde, furan, and 2-butene-1,4-dial. The addition of water to the reaction stream substantially increased catalyst activity and improved selectivity to crotonaldehyde and furan at specific reaction temperatures. At higher water addition concentrations, furan selectivity increased from 12% to over 25%. The catalytic effects of water addition were related to competitive adsorption with various V{sub 2}O{sub 5}-based surface sites, including the vanadyl V=O, corner sharing V-O-V and edge sharing V-O oxygen. Higher levels of water addition were proposed to impose acidic character by dissociative adsorption. In addition, a novel combinatorial synthesis technique for VMoO was used to investigate the phase transitions of V{sub 2}O{sub 5}, solid solutions of Mo in V{sub 2}O{sub 5}, V{sub 9}Mo{sub 6}O{sub 40}, and other reduced VMoO compounds, characterized by laser Raman spectroscopy. The natural composition gradient imposed by the sputter deposition apparatus was used to create VMoO arrays containing 225 samples ranging from 7.0-42 mol% MoO{sub 3}/(V{sub 2}O{sub 5} + MoO{sub 3}), determined by EDS analysis.

  11. Effects of Smoking Cessation on Eight Urinary Tobacco Carcinogen and Toxicant Biomarkers

    Science.gov (United States)

    Carmella, Steven G.; Chen, Menglan; Han, Shaomei; Briggs, Anna; Jensen, Joni; Hatsukami, Dorothy K.; Hecht, Stephen S.

    2009-01-01

    We determined the persistence at various times (3, 7, 14, 21, 28, 42 and 56 days) of eight tobacco smoke carcinogen and toxicant biomarkers in the urine of 17 smokers who stopped smoking. The biomarkers were 1-hydroxy-2-(N-acetylcysteinyl)-3-butene (1) and 1-(N-acetylcysteinyl)-2-hydroxy-3-butene (2) [collectively called MHBMA for monohydroxybutyl mercapturic acid] and 1,2-dihydroxy-4-(N-acetylcysteinyl)butane (3) [DHBMA for dihydroxybutyl mercapturic acid], metabolites of 1,3-butadiene; 1-(N-acetylcysteinyl)-propan-3-ol (4, HPMA for 3-hydroxypropyl mercapturic acid), a metabolite of acrolein; 2-(N-acetylcysteinyl)butan-4-ol (5, HBMA for 4-hydroxybut-2-yl mercapturic acid), a metabolite of crotonaldehyde; (N-acetylcysteinyl)benzene (6, SPMA for S-phenyl mercapturic acid), a metabolite of benzene; (N-acetylcysteinyl)ethanol (7, HEMA for 2-hydroxyethyl mercapturic acid), a metabolite of ethylene oxide; 1-hydroxypyrene (8) and its glucuronides (1-HOP), metabolites of pyrene; and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (9) and its glucuronides (total NNAL), a biomarker of exposure to 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). These biomarkers represent some of the major carcinogens and toxicants in cigarette smoke: 1,3-butadiene, acrolein, crotonaldehyde, benzene, ethylene oxide, polycyclic aromatic hydrocarbons (PAH), and NNK. With the exception of DHBMA, levels of which did not change after cessation of smoking, all other biomarkers decreased significantly after 3 days of cessation (P<0.001). The decreases in MHBMA, HPMA, HBMA, SPMA, and HEMA were rapid, nearly reaching their ultimate levels (81 – 91% reduction) after 3 days. The decrease in total NNAL was gradual, reaching 92% after 42 days, while reduction in 1-HOP was variable among subjects to about 50% of baseline. Since DHBMA did not change upon smoking cessation, there appear to be sources of this metabolite other than 1,3-butadiene. The results of this study demonstrate that the tobacco

  12. Quantitative analysis of volatile organic compounds released and consumed by rat L6 skeletal muscle cells in vitro.

    Science.gov (United States)

    Mochalski, Paweł; Al-Zoairy, Ramona; Niederwanger, Andreas; Unterkofler, Karl; Amann, Anton

    2014-12-01

    Knowledge of the release of volatile organic compounds (VOCs) by cells provides important information on the origin of VOCs in exhaled breath. Muscle cells are particularly important, since their release of volatiles during the exertion of an effort contributes considerably to breath concentration profiles. Presently, the cultivation of human skeletal muscle cells is encountering a number of obstacles, necessitating the use of animal muscle cells in in vitro studies. Rat L6 skeletal muscle cells are therefore commonly used as a model for studying the molecular mechanisms of human skeletal muscle differentiation and functions, and facilitate the study of the origin and metabolic fate of the endogenously produced compounds observed in breath and skin emanations. Within this study the production and uptake of VOCs by rat L6 skeletal muscle cells were investigated using gas chromatography with mass spectrometric detection, combined with head-space needle trap extraction as the pre-concentration technique (HS-NTE-GC-MS). Seven compounds were found to be produced, whereas sixteen species were consumed (Wilcoxon signed-rank test, p < 0.05) by the cells being studied. The set of released volatiles included two ketones (2-pentanone and 2-nonanone), two volatile sulphur compounds (dimethyl sulfide and methyl 5-methyl-2-furyl sulphide), and three hydrocarbons (2-methyl 1-propene, n-pentane and isoprene). Of the metabolized species there were thirteen aldehydes (2-propenal, 2-methyl 2-propenal, 2-methyl propanal, 2-butenal, 2-methyl butanal, 3-methyl butanal, n-pentanal, 2-methyl 2-butenal, n-hexanal, benzaldehyde, n-octanal, n-nonanal and n-decanal), two esters (n-propyl propionate and n-butyl acetate), and one volatile sulphur compound (dimethyl disulfide). The possible metabolic pathways leading to the uptake and release of these compounds by L6 cells are proposed and discussed. An analysis of the VOCs showed them to have huge potential for the identification and

  13. 炼厂碳四资源的利用途径%Utilization ways of refinery C4

    Institute of Scientific and Technical Information of China (English)

    王定博

    2014-01-01

    对国内炼厂碳四的利用状况进行了分析,对混合碳四与甲醇合成甲基叔丁基醚,正丁烯经水合、脱氢反应制备甲乙酮和正丁烯与乙酸反应制备乙酸仲丁酯的生产情况进行了介绍;对醚后混合碳四制丙烯和乙烯、异构化制异丁烯、芳构化、与乙酸反应制备乙酸仲丁酯的应用和研究状况进行了分析,认为利用醚后混合碳四制备丙烯和制备乙酸仲丁酯是未来的发展方向;对异丁烷脱氢、异丁烷选择氧化、正丁烷制顺酐等技术研究进展和使用现状进行简述,认为异丁烷的利用是未来的研究重点。%This paper analyzes utilization of C4 in China,and introduces the manufactures of methyl tert-butyl ether synthesized from mixed C4 and methanol,methyl ethyl ketone prepared by n-butene through hydration reaction and dehydrogenation reaction,sec-butyl acetate from n-butene and acetic acid. Also,it briefly describes the investigations on reactions of mixed C4 after production of MTBE to prepare propylene and ethylene,isobutene by isomerization,sec-butyl acetate by reaction with acetic acid,and aromatization. Accordingly,it forecasts their market prospects respectively. Preparations of propylene and sec-butyl acetate from mixed C4 are proved to be the most promising ways. Through comparing the technologies of isobutane dehydrogenation,selective oxidation of isobutane,and reaction of n-butane to prepare maleic anhydride,utilization of iso-butane is thought to be future research focus.

  14. Key Roles of Lewis Acid-Base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion.

    Science.gov (United States)

    Sun, Junming; Baylon, Rebecca A L; Liu, Changjun; Mei, Donghai; Martin, Kevin J; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-20

    The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Brønsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Brønsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Brønsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (∼ 88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Brønsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (catalyst for C-C coupling via aldolization reaction. PMID:26624526

  15. Reactions of coal model compounds in tetralin using microwave energy: Effects of catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Eray, E.; Yagmur, E.; Simsek, E.H.; Alibeyli, R.; Togrul, T. [Ankara University, Ankara (Turkey). Faculty for Engineering

    2006-10-01

    Reaction mechanisms of model compounds of coal in tetralin by microwave energy were investigated. Diphenylmethane (DFM), phenyl-methyl ether (anisole), and phenyl-methyl ketone (acetophenon) were chosen as model compounds. Experiments were carried out for 10 minutes of microwave energy and different catalysts were used (pyratol, zeolite, BaCl{sub 2}, AlNiMo) to find out the distribution of reaction products of the model compounds. GC and GC/MS are used to analyze the reaction products. The main reaction products from DFM and tetralin under microwave radiation with catalysts were ethyl benzene, naphthalene, 2-methyl naphthalene, 3,4-dihydronaphthaleneone, 1-1'-ethyldene 1-benzene, and 1-methyl 4-phenyl methyl benzene. The main reaction products from anisole and tetralin under microwave radiation were ethyl benzene, phenol, methyl phenol, decahydronaphthalene, and tetrahydronaphthalenol. The main reaction products from acetophenon and tetralin under microwave radiation with catalysts were ethyl benzene, methoxy benzene, decahydronaphthalene, naphthalene, tetrahydronaphthalenol, 3,4-dihydronaphthalenone and 2-butene-1-one-1,3 diphenyl. The estimated mechanism of the model compounds with tetralin is compared with the results taken from GC/MS analysis. It is obtained that the results suggested theoretically were similar with the GC/MS results.

  16. Kinetics of the Epoxidation of Geraniol and Model Systems by Dimethyldioxirane

    Directory of Open Access Journals (Sweden)

    B. S. Crow

    2004-02-01

    Full Text Available The mono-epoxidation of geraniol by dimethyldioxirane was carried out invarious solvents. In all cases, the product ratios for the 2,3 and 6,7 mono-epoxides werein agreement with literature values. Kinetic studies were carried out at 23 oC in thefollowing dried solvent systems: acetone (k2 = 1.49 M-1s-1, carbon tetrachloride/acetone(9/1, k2=2.19 M-1s-1, and methanol/acetone (9/1, k2 = 17 M-1s-1. Individual k2 valueswere calculated for epoxidation of the 2,3 and 6,7 positions in geraniol. The non-conjugated diene system was modeled employing two simple independent alkenes:2-methyl-2-pentene and 3-methyl-2-buten-1-ol by determining the respective k2 valuesfor epoxidation in various solvents. The kinetic results for each independent alkeneshowed that the relative reactivity of the two epoxidation sites in geraniol as a function ofsolvent was not simply a summation of the independent alkene systems.

  17. Rich methane premixed laminar flames doped by light unsaturated hydrocarbons - Part I : allene and propyne

    CERN Document Server

    Gueniche, Hadj-Ali; Dayma, Guillaume; Fournet, Ren{é}; Battin-Leclerc, Fr{é}d{é}rique

    2006-01-01

    The structure of three laminar premixed rich flames has been investigated: a pure methane flame and two methane flames doped by allene and propyne, respectively. The gases of the three flames contain 20.9% (molar) of methane and 33.4% of oxygen, corresponding to an equivalence ratio of 1.25 for the pure methane flame. In both doped flames, 2.49% of C3H4 was added, corresponding to a ratio C3H4/CH4 of 12% and an equivalence ratio of 1.55. The three flames have been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz microprobe. Quantified species included carbon monoxide and dioxide, methane, oxygen, hydrogen, ethane, ethylene, acetylene, propyne, allene, propene, propane, 1,2-butadiene, 1,3-butadiene, 1-butene, isobutene, 1-butyne, vinylacetylene, and benzene. The temperature was measured using a PtRh (6%)-PtRh (30%) thermocou...

  18. Influence of ethanol-gasoline blended fuel on emission characteristics from a four-stroke motorcycle engine.

    Science.gov (United States)

    Jia, Li-Wei; Shen, Mei-Qing; Wang, Jun; Lin, Man-Qun

    2005-08-31

    Emission characteristics from a four-stroke motorcycle engine using 10% (v/v) ethanol-gasoline blended fuel (E10) were investigated at different driving modes on the chassis dynamometers. The results indicate that CO and HC emissions in the engine exhaust are lower with the operation of E10 as compared to the use of unleaded gasoline, whereas the effect of ethanol on NO(X) emission is not significant. Furthermore, species of both unburned hydrocarbons and their ramifications were analyzed by the combination of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). This analysis shows that aromatic compounds (benzene, toluene, xylene isomers (o-xylene, m-xylene and p-xylene), ethyltoluene isomers (o-ethyltoluene, m-ethyltoluene and p-ethyltoluene) and trimethylbenzene isomers (1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene)) and fatty group ones (ethylene, methane, acetaldehyde, ethanol, butene, pentane and hexane) are major compounds in motorcycle engine exhaust. It is found that the E10-fueled motorcycle engine produces more ethylene, acetaldehyde and ethanol emissions than unleaded gasoline engine does. The no significant reduction of aromatics is observed in the case of ethanol-gasoline blended fuel. The ethanol-gasoline blended fuel can somewhat improve emissions of the rest species. PMID:15923082

  19. Direct Dehydrogenation of n-Butane Over Pt/Sn/Zn-K/Al2O3 Catalyst: Effect of Hydrogen in the Feed.

    Science.gov (United States)

    Lee, Jong Kwon; Seo, Hyun; Kim, Jeong Kwon; Seo, Hanuk; Cho, Hye-Ran; Lee, Jinsuk; Chang, Hosik; Song, In Kyu

    2016-05-01

    Al2O3 was prepared by a sol-gel method for use as a support. Pt/Sn/Zn-K/Al2O3 catalyst was then prepared by a sequential impregnation method, and it was applied to the direct dehydrogenation of n-butane to n-butenes and 1,3-butadiene. Physicochemical properties of Pt/Sn/Zn-K/Al2O3 catalyst were examined by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm, inductively coupled plasma atomic emission spectroscopy (ICP-AES), temperature-programmed reduction (TPR), CO chemisorption, and temperature-programmed oxidation (TPO) measurements. In order to improve the catalyst stability, the effect of hydrogen in the feed on the catalytic performance in the direct dehydrogenation of n-butane was studied. The catalyst stability and reusability in the direct dehydrogenation of n-butane was also investigated. Experimental results revealed that the addition of hydrogen in the feed decreased conversion of n-butane and yield for total dehydrogenation products but improved the stability of the catalyst. The catalytic activity and stability of regenerated Pt/Sn/Zn-K/Al2O3 catalyst in the presence of hydrogen slightly decreased compared to those of fresh Pt/Sn/Zn-K/Al2O3 catalyst due to the slight sintering of platinum particles.

  20. Reactivity of palladium nano-particles supported in hydrogenation: role of particles surface density; Reactivite des nanoparticules de palladium supportees en hydrogenation: role de la densite surfacique de particules

    Energy Technology Data Exchange (ETDEWEB)

    Benkhaled, M.

    2004-10-01

    The objective of this work is to investigate the influence of the particle surface density on the hydrogenation of polyunsaturated compounds (buta-1,3-diene, ortho-xylene). Highly dispersed Pd/Al{sub 2}O{sub 3} ({gamma} and {delta}-Al{sub 2}O{sub 3}) catalysts were prepared from Pd(nitrite) complexes (size < 7 angstrom, controlled by TEM, HAADF, EXAFS and CO chemisorption). Increasing the particle surface density from 2240 to 12880 particles/{mu}m{sup 2} leads to a modification of the electronic properties as evidenced by CO-FTIR, XPS and XANES. By contrast, the comparison of the supports at iso-density showed no significant difference of the physico-chemical properties of the supported metal particles. In parallel, the catalytic performances in hydrogenation of butadiene and butenes are very sensitive both to the nature of the support for the same density and to the surface density for the same support. It was shown that the reactions of hydrogenation could be controlled at the same time by the electronic properties of the metal nano-particles but also by the phenomenon of hydrogen diffusion around the particles on a zone of support. In this case, the support can play the part of hydrogen tank. (author)

  1. Reactions of a stable dialkylsilylene and their mechanisms

    Indian Academy of Sciences (India)

    Mitsuo Kira

    2012-11-01

    Various reactions for a stable dialkylsilylene, 2,2,5,5-tetrakis(trimethylsilyl)silacyclopentane-1,1-diyl (1), are summarized and their mechanisms are discussed. Silylene 1 isomerizes to the corresponding silaethene via the 1,2-trimethylsilyl migration. Reduction of 1 with alkali metals affords the corresponding radical anion 1.− with a relatively small 29Si hfs constant (2.99 mT) and a large g-factor (g = 2.0077) compared with those for trivalent silyl radicals. Photo-excitation of 1 generates the corresponding singlet excited state (11*) with the lifetime of 80.5 ns. The excited state reacts with C=C double bond compounds including benzene, naphthalene, and ()- and ()-2-butenes. Although the thermal reactions of 1 with haloalkanes occur via radical mechanisms, the insertion into O-H, Si-H and Si-Cl bonds proceeds concertedly via the threemembered cyclic transition states. The reaction of 1 with H2SiCl2 gives the Si-Cl insertion product exclusively, while the quantitative insertion to Si-H bond occurs when Me2SiHCl is used as a substrate. The origin of the rather unusual Si-H/Si-Cl selectivity is elucidated using DFT calculations. Silylene 1 adds to C=C, C≡C, and C=O bonds to afford the corresponding silacycles as stable compounds. The importance of the carbonyl silaylides during the reactions of silylenes with aldehydes and ketones is emphasized.

  2. Selection of organic Rankine cycle working fluid based on unit-heat-exchange-area net power

    Institute of Scientific and Technical Information of China (English)

    郭美茹; 朱启的; 孙志强; 周天; 周孑民

    2015-01-01

    To improve energy conversion efficiency, optimization of the working fluids in organic Rankine cycles (ORCs) was explored in the range of low-temperature heat sources. The concept of unit-heat-exchange-area (UHEA) net power, embodying the cost/performance ratio of an ORC system, was proposed as a new indicator to judge the suitability of ORC working fluids on a given condition. The heat exchange area was computed by an improved evaporator model without fixing the minimum temperature difference between working fluid and hot fluid, and the flow pattern transition during heat exchange was also taken into account. The maximum UHEA net powers obtained show that dry organic fluids are more suitable for ORCs than wet organic fluids to recover low-temperature heat. The organic fluid 1-butene is recommended if the inlet temperature of hot fluid is 353.15−363.15 K or 443.15−453.15 K, heptane is more suitable at 373.15−423.15 K, and R245ca is a good option at 483.15−503.15 K.

  3. Laccase oxidation and removal of toxicants released during combustion processes.

    Science.gov (United States)

    Prasetyo, Endry Nugroho; Semlitsch, Stefan; Nyanhongo, Gibson S; Lemmouchi, Yahia; Guebitz, Georg M

    2016-02-01

    This study reports for the first time the ability of laccases adsorbed on cellulose acetate to eliminate toxicants released during combustion processes. Laccases directly oxidized and eliminated more than 40% w/v of 14 mM of 1,4-dihydroxybenzene (hydroquinone); 2-methyl-1,4-benzenediol (methylhydroquinone); 1,4-dihydroxy-2,3,5-trimethylbenzene (trimethylhydroquinone); 3-methylphenol (m-cresol); 4-methylphenol (p-cresol); 2-methylphenol (o-cresol); 1,3-benzenediol (resorcinol); 1,2-dihydroxybenzene (catechol); 3,4-dihydroxytoluene (4-methylcatechol) and 2-naphthylamine. Further, laccase oxidized 2-naphthylamine, hydroquinone, catechol, methylhydroquinone and methylcatechol were also able to in turn mediate the elimination of >90% w/v of toxicants which are per-se non-laccase substrates such as 3-aminobiphenyl; 4-aminobiphenyl; benz[a]anthracene; 3-(1-nitrosopyrrolidin-2-yl) pyridine (NNN); formaldehyde; 4-(methyl-nitrosamino-1-(3-pyridyl)-1-butanone (NNK); 2-butenal (crotonaldehyde); nitric oxide and vinyl cyanide (acrylonitrile). These studies demonstrate the potential of laccase immobilized on solid supports to remove many structurally different toxicants released during combustion processes. This system has great potential application for in situ removal of toxicants in the manufacturing, food processing and food service industries. PMID:26408262

  4. Effect of Ni2+ on Catalytic Activity of Et3NHCl/AlCl3 Ionic Liquid for Alkylation of Isobutane%Ni2+的引入对离子液体烷基化催化性能的影响

    Institute of Scientific and Technical Information of China (English)

    张彦红; 刘植昌; 黄崇品; 高金森

    2003-01-01

    @@ The alkylation of isobutane with butene is an important process for the production of high quality petroleum. In place of concentrated sulfuric acid, Et3NHCl/AlCl3 ionic liquid has been used in the reaction with fairly good effect[1], but there is still a big difference compared with the results of concentrated sulfuric acid. The C8 content in the alkylates obtained with concentrated sulfuric acid was 72.1%[2], but it was only 56% with the ionic liquid. The key reaction in the alkylation is hydrogen transfer from C+8 to C08[3], and this is the main reason for the difference between the ionic liquid and concentrated sulfuric acid. In the present paper, a nickel promotor was added to Et3NHCl/AlCl3 ionic liquid, and the modified ionic liquid was used to catalyze the alkylation reaction with/without hydrogen. The structure of the modified ionic liquid was analyzed using FABMS (fast atom bombardment mass spectrometry).

  5. A chemical assessment of the suitability of allyl- iso-propyltelluride as a Te precursor for metal organic vapour phase epitaxy

    Science.gov (United States)

    Hails, Janet E.; Cole-Hamilton, David J.; Stevenson, John; Bell, William; Foster, Douglas F.; Ellis, David

    2001-04-01

    The chemical studies, which led to the testing of allyl- iso-propyltelluride (allylTePr i) as a Te precursor in metal organic vapour phase epitaxy are presented. The pyrolysis in hydrogen of allylTePr i gave products including 1,5-hexadiene, propane and propene. Co-pyrolysis of dimethylcadmium (Me 2Cd) and allylTePr i gave the hydrocarbons expected from the pyrolysis of the individual precursors plus additional hydrocarbons including 2-methylpropane and 1-butene. Plots of percentage decomposition versus temperature, which proved extremely useful in determining the likely growth temperatures for both CdTe and HgTe, showed that allylTePr i is less stable than both Pr 2iTe (di- iso-propyltelluride) and Me 2Cd. The possible role of Hg in the growth of CdTe is also discussed. The chemistry of allylTePr i is well suited for use as an efficient precursor for epitaxial growth of tellurium containing semiconductors since there is very little formation of other organotellurium compounds on pyrolysis.

  6. An operando FTIR spectroscopic and kinetic study of carbon monoxide pressure influence on rhodium-catalyzed olefin hydroformylation.

    Science.gov (United States)

    Kubis, Christoph; Sawall, Mathias; Block, Axel; Neymeyr, Klaus; Ludwig, Ralf; Börner, Armin; Selent, Detlef

    2014-09-01

    The influence of carbon monoxide concentration on the kinetics of the hydroformylation of 3,3-dimethyl-1-butene with a phosphite-modified rhodium catalyst has been studied for the pressure range p(CO)=0.20-3.83 MPa. Highly resolved time-dependent concentration profiles of the organometallic intermediates were derived from IR spectroscopic data collected in situ for the entire olefin-conversion range. The dynamics of the catalyst and organic components are described by enzyme-type kinetics with competitive and uncompetitive inhibition reactions involving carbon monoxide taken into account. Saturation of the alkyl-rhodium intermediates with carbon monoxide as a cosubstrate occurs between 1.5 and 2 MPa of carbon monoxide pressure, which brings about a convergence of aldehyde regioselectivity. Hydrogenolysis of the acyl intermediate is fast at 30 °C and low pressure of p(CO)=0.2 MPa, but is of minus first order with respect to the solution concentration of carbon monoxide. Resting 18-electron hydrido and acyl complexes that correspond to early and late rate-determining states, respectively, coexist as long as the conversion of the substrate is not complete. PMID:25081298

  7. Synthesis and Characterization of Plant based Polythiophene Copolymers for Light Harvesting Applications

    Science.gov (United States)

    Kodithuwakku, Udari; Malavi Arachchi, Prashantha; Ratnaweera, Dilru

    Polythiophenes became more attractive in diverse applications due to some of their inherent properties including thermal and environmental stability as well as optical and electronic conductive properties. Commonly thiophene monomers are obtained from byproducts of crude oils. The current study discuss for the first time the synthesis and characterization of light harvesting polythiophenes copolymers from thiophene derivatives extracted from Tagetes species. There were mainly two thiophenes derivatives, 5-(3-buten-1-ynyl)-2, 2-bithienyl and 2, 2', 5, 2''-terthienyl (terthiophene), in the roots of the plant. Chemical oxidative radical polymerization was followed during the synthesis of copolymers with various block compositions of plant based terthiophenes and 3-hexyl terthiophenes. Structural characterization of the synthetic products was done using FTIR, NMR, Uv-vis, XRD and DSC techniques. Polythiophene homopolymers obtained from plant based terthiophenes have limited processability of solar cells due to poor solubility in common organic solvents. A significant solubility improvement was observed with copolymers having minor contributions of 3-hexylthiophenes. Research Grants, University of Sri Jayewardenepura, Sri Lanka.

  8. Biocomposites based on Argan nut shell and a polymer matrix: Effect of filler content and coupling agent.

    Science.gov (United States)

    Essabir, Hamid; Bensalah, Mohammed Ouadi; Rodrigue, Denis; Bouhfid, Rachid; Qaiss, Abou El Kacem

    2016-06-01

    This study aimed at developing a biocomposite using polypropylene (PP) as the matrix and Argan nut shell (ANS) as reinforcement. Also, styrene-(ethylene-butene)-styrene triblock copolymer grafted with maleic anhydride (SEBS-g-MA) was used as a coupling agent. The samples were prepared by using extrusion compounding followed by injection molding to determine the effect of filler and coupling agent content on the morphological, thermal, mechanical, and hygroscopic properties of the biocomposites. SEM micrographs revealed that good ANS dispersion/distribution into PP was achieved with an important reduction of fiber pull-out, micro-spaces, and voids with coupling agent addition. This led to substantial improvement intension, torsion, and water absorption reduction due to improved interfacial adhesion. Although ANS particles did not significantly modify the thermal stability of PP, the use of a coupling agent increased it. The experimental data were compared with several theoretical models such Voigt, Reuss, Hirsch, and Tsai-Pagano to characterize the interfacial adhesion quality and to determine the elastic modulus of a single ANS particle. Finally, all the results show that Argan waste to produce PP biocomposites is an interesting avenue to effectively deal with agricultural wastes and develop valuable industrial and practical applications. PMID:27083345

  9. Development of device for trapping a superheated liquid drop and life-time measurements of the drop by radiation-induced evaporation

    Energy Technology Data Exchange (ETDEWEB)

    Sawamura, Teruko; Sugiyama, Noriyuki; Homma, Akira; Narita, Masakuni [Hokkaido Univ., Sapporo (Japan). Faculty of Engineering

    1999-08-01

    In this study a detection sensitivity evaluation was made by measuring the life time of a single liquid drop. A device trapping a superheated drop was developed, where a single drop of test liquid was trapped at a specified position and then irradiated. Therefore, the volume of the drop can be measured before the irradiation. Wakeshima originally developed the device, in which a test liquid drop was injected and superheated in a supporting liquid, to measure the limit of superheat of the liquid. Apfel modified Wakeshima's device by applying an acoustic field to be able to trap and decompress a superheated liquid drop. The device in the present study is similar to Apfel's. But the inlet part is cooled because the boiling point of the test liquid is lower than room temperature. In this device the superheated drop of trans-2-butene (C{sub 4}H{sub 8}, boiling point=0.8degC) was exposed to Am-Be neutrons and {sup 60}Co {gamma}-rays and its life time was measured. (author)

  10. Product Identification and Mass Spectrometric Analysis of n-Butane and i-Butane Pyrolysis at Low Pressure

    Institute of Scientific and Technical Information of China (English)

    Yi-jun Zhang; Wen-hao Yuan; Jiang-huai Cai; Li-dong Zhang; Fei Qi; Yu-yang Li

    2013-01-01

    The pyrolysis of n-butane andi-butane at low pressure was investigated from 823-1823 K in an electrically heated flow reactor using synchrotron vacuum ultraviolet photoionization mass spectrometry.More than 20 species,especially several radicals and isomers,were detected and identified from the measurements of photoionization efficiency (PIE) spectra.Based on the mass spectrometric analysis,the characteristics of n-butane and i-butane pyrolysis were discussed,which provided experimental evidences for the discussion of decomposition pathways of butane isomers.It is concluded that the isomeric structures of n-butane and i-butane have strong influence on their main decomposition pathways,and lead to dramatic differences in their mass spectra and PIE spectra such as the different dominant products and isomeric structures of butene products.Furthermore,compared with n-butane,i-butane can produce strong signals of benzene at low temperature in its pyrolysis due to the enhanced formation of benzene precursors like propargyl and C4 species,which provides experimental clues to explain the higher sooting tendencies of iso-alkanes than n-alkanes.

  11. Evidence for alkali metal induced intermolecular acetylenic hydrogen atom transfer between hydrogen-bonded alkyne complexes in solid argon

    International Nuclear Information System (INIS)

    Condensation of acetylene, propyne, and 2-butyne/acetylene mixtures with heavy alkali metal atoms (Na, K, Cs) in an argon matrix at 15 K has led to the appearance of infrared absorptions due to ethylene, propylene, and trans-2-butene, respectively. These results stand in sharp contrast with the products obtained with lithium. Isotopic studies have shown that ethylene formation involved three different acetylene molecules and evidenced a difference in the product yield with hydrogen vs. deuterium as well as a preference for trans- vs. cis-C2H2D2 formation, which is discussed and rationalized by differences in the zero point energies for the different mixed deuterium isotopes of the intermediate vinyl radical. This trend is amplified by methyl substitution. Spectroscopic evidence was found in these experiments for cesium acetylide (Cs+C2H-) and a cesium-acetylene π complex, which are involved in the intermolecular acetylenic hydrogen atom transfer process. 26 references, 3 figures, 2 tables

  12. Investigation of the NH-π hydrogen bond interaction in the aniline-alkene (C2H4,C3H6,C4H8) cluster cations by infrared depletion spectroscopy

    International Nuclear Information System (INIS)

    The vibrational spectra of the NH stretching vibrations of aniline-alkene cluster cations have been measured using infrared depletion method. Aniline-ethene cation showed three strong absorption bands at 3448, 3314 and 3220 cm-1. The comparison with MO calculation has shown that the main intermolecular interaction is the NH-π type hydrogen bond between one of the NH bonds of aniline cation and π-electron of ethene, which is different from that observed for the neutral aniline-ethene cluster. The bands at 3448 and 3220 cm-1 have been assigned to the stretching vibrations of free NH and bonded NH, respectively, and the band at 3314 cm-1 to the binary overtone of the NH2 deformation vibration. Similar results have been obtained for aniline-propene and aniline-butene cluster cations. The red shift of the stretching vibration of free NH bond of aniline cation agreed with that expected from the correlation with the proton affinity of the acceptor molecule obtained for the aniline-aromatic cluster cations (NH-π type)

  13. Olefin metathesis : tapping into breakthrough chemical technology

    Energy Technology Data Exchange (ETDEWEB)

    Granson, E.

    2010-06-15

    Olefin metathesis is a catalyst technology where 2 double bond-containing molecules or olefins are split in order to exchange atoms and result in the formation of 2 new molecules or substances. Earlier researchers used a variety of materials to convert propylene into a mixture of butenes and ethylenes. A method developed by Shell researchers produces linear olefins used as detergent feedstocks. In 1971, scientists used a metal-carbene catalyst to react with the olefins to produce both a new olefin and a new metal carbene in order to perpetuate the process. In 2002, a new metathesis technology was developed using renewable natural oils as a feedstock. The catalyst is introduced as a solid into the oil, and then agitated by stirring. The modified oil is then reacted with hydrogen to remove the double bonds and filter off the catalyst. The method is offered on a contract basis by Elevance Renewable Sciences in a variety of application. The process was designed to take place at lower temperatures with the release of fewer greenhouse gases (GHGs). New metathesis technologies are also being developed to reduce the molecular weight of polymers in order to reduce viscosity and increase flow. 3 figs.

  14. Catalytic studies of nitric oxide: A. Reduction of nitric oxide with methane over alumina supported rhidium. B. Characterization of alumina supported cobalt molybdate for olefin metathesis

    Energy Technology Data Exchange (ETDEWEB)

    Hardee, J.R.

    1978-01-01

    Kinetic studies at 300/sup 0/-400/sup 0/C in a gradientless recirculating reactor showed that nitric oxide reduction was first order in methane and -0.63 order in nitric oxide, with an activation energy of 18.4 kcal/mole, and a deuterium kinetic isotope effect of 1.9, suggesting that dissociative methane adsorption is the rate-determining step. Nitrogen-15 tracer studies showed that the reaction involves N/sub 2/O as a surface intermediate, and a mechanism is proposed involving two-step dissociation of adsorbed NO to adsorbed N/sub 2/O and N/sub 2/ and surface oxygen atoms, which rapidly poison the catalyst unless removed by methane. Propylene metathesis to ethylene and 2-butene over cobalt molybdate was studied by nitric oxide poisoning and shown to follow Langmuir-Hinshelwood kinetics. Two different dual-site mechanisms, one involving propylene adsorption on adjacent molybdenum atoms and the other involving adsorption of two propylene molecules on one molybdenum atom, fit the data equally well. An upper limit to the active site density was determined as 2.5 x 10/sup 13//sq cm at 27/sup 0/C, i.e., only 9Vertical Bar3< of the surface molybdenum atom density.

  15. Nature of active centers and mechanism of olefin metathesis on applied oxide catalysts of molybdenum, tungsten and rhenium

    Energy Technology Data Exchange (ETDEWEB)

    Kadushin, A.A. (USSR Academy of Sciences); Aliyev, R.K.; Krylov, O.V.; Andreyev, A.A.; Yedreva-Kardzhiyeva, R.M.; Shopov, D.M.

    1982-03-01

    The authors undertook a systematic study of the effects of the carrier, activation conditions and the reaction itself on the formation and structure of active centers. Spectral characteristics of the systems studied were compared by infrared, ultraviolet, X-ray-electron and electron absorption spectroscopy, and X-ray-phase and chromatographic analyses. Catalytic activity in a metathesis reaction of propylene and butene-1 was tested in a quartz flow reactor at atmospheric pressure in a temperature range of 25-600/sup 0/C, with contact time of 3-50 seconds. The deposited oxide catalysts of the title minerals are discussed in terms of preparing the catalysts, studying their activity, and observing optical spectra. Tungsten ions were found to reduce at higher temperatures than molbydenum ions. Olefin treatment brought reduction of rhenium to lower oxidation levels. The low activities of Re/sub 2/O/sub 7//MgO at low temperatures is related to difficult electron transfer. The studies indicated the presence of a mobile center in the metathesis of olefins for oxide catalysis of all 3 title minerals, which is dependent on the chemical nature of the carrier and its crystalline structure.

  16. Thermal and rheological behavior of reactive blends from metallocene olefin elastomers and polypropylene

    Directory of Open Access Journals (Sweden)

    Nei S. Domingues Junior

    2012-01-01

    Full Text Available Reactive blends of metallocene polyolefin elastomers (POE/polypropylene (PP with 60/40 composition were prepared with an organic peroxide, 2,5-dimethyl-2,5-di-(t-butylperoxyhexane, and a bis-azide derivative, diphenyloxid-4,4'-bis(sulfonylazide (BSA. Ethylene-1-butene (EB and ethylene-1-octene (EO copolymers and elastomeric polypropylene (ePP were used as the elastomeric phase. The effect of elastomeric phase on the thermal, rheological, morphological and mechanical properties of the thermoplastic vulcanizates (TPVs or dynamic vulcanizates were studied. All TPVs depicted pseudoplastic behavior and blends cured with azide curative showed higher viscosities. The TPVs showed both dispersed and continuous phase morphology that depends on the elastomeric phase type revealing a limited degree of compatibility between PP and the elastomers EO or EB. On the other hand, the TPV PP/ePP showed a uniform morphology suggesting an improved compatibility. Substantial changes observed in physical properties were explained on the basis of blends' morphology and dynamic vulcanization. The results confirm that the mechanical properties are more influenced by the elastomeric phase than by the curative agent. This study revealed a broad new range of opportunities for POE-based TPVs.

  17. Impact of co-adsorbed oxygen on crotonaldehyde adsorption over gold nanoclusters: a computational study.

    Science.gov (United States)

    Zeinalipour-Yazdi, Constantinos D; Willock, David J; Machado, Andreia; Wilson, Karen; Lee, Adam F

    2014-06-21

    Crotonaldehyde (2-butenal) adsorption over gold sub-nanometer particles, and the influence of co-adsorbed oxygen, has been systematically investigated by computational methods. Using density functional theory, the adsorption energetics of crotonaldehyde on bare and oxidised gold clusters (Au13, d = 0.8 nm) were determined as a function of oxygen coverage and coordination geometry. At low oxygen coverage, sites are available for which crotonaldehyde adsorption is enhanced relative to bare Au clusters by 10 kJ mol(-1). At higher oxygen coverage, crotonaldehyde is forced to adsorb in close proximity to oxygen weakening adsorption by up to 60 kJ mol(-1) relative to bare Au. Bonding geometries, density of states plots and Bader analysis, are used to elucidate crotonaldehyde bonding to gold nanoparticles in terms of partial electron transfer from Au to crotonaldehyde, and note that donation to gold from crotonaldehyde also becomes significant following metal oxidation. At high oxygen coverage we find that all molecular adsorption sites have a neighbouring, destabilising, oxygen adatom so that despite enhanced donation, crotonaldehyde adsorption is always weakened by steric interactions. For a larger cluster (Au38, d = 1.1 nm) crotonaldehyde adsorption is destabilized in this way even at a low oxygen coverage. These findings provide a quantitative framework to underpin the experimentally observed influence of oxygen on the selective oxidation of crotyl alcohol to crotonaldehyde over gold and gold-palladium alloys.

  18. Topological Constraints on Chain-Folding Structure of Semicrystalline Polymer as Studied by 13C-13C Double Quantum NMR

    Science.gov (United States)

    Hong, Youlee; Miyoshi, Toshikazu

    Chain-folding process is a prominent feature of long polymer chains during crystallization. Over the last half century, much effort has been paid to reveal the chain trajectory. Even though various chain-folding models as well as theories of crystallization at molecule levels have been proposed, they could be not reconciled due to the limited experimental evidences. Recent development of double quantum NMR with selective isotope labeling identified the chain-trajectory of 13C labeled isotactic poly(1-butene). The systematic experiments covered a wide range of parameters, i.e. kinetics, concentration, and molecular weight (Mw) . It was demonstrated that i) adjacent re-entry site was invariant as a function of crystallization temperature (Tc) , concentration, andMw, ii) long-range order of adjacent re-entry sequence is independence of kinetics at a given concentration while it decreased with increasing the polymer concentration at a given Tc due to the increased interruption between the chains, and iii) high Mw chains led to the multilayer folded structures in single crystals, but the melt state induced the identical short adjacent sequences of long and short polymer over a wide range of Tc due to the entanglements. The behaviors indicated that the topological restriction plays significant roles in the chain-folding process rather than the kinetics. The proposed framework to control the chain-folding structure presents a new perspective into the chain organization by either the intra- or inter-chain interaction. National Science Foundation Grants DMR-1105829 and 1408855.

  19. Do we need an Ad hoc chemical mechanism for Mexico City's photochemical smog?

    Science.gov (United States)

    Ruiz-Suárez, L. G.; Castro, T.; Mar, B.; Ruiz-Santoyo, M. E.; Cruz, X.

    Chemical mechanisms in mathematical models for air quality studies represent the synthesis of about 30 years of research in gas kinetics and atmospheric chemistry, and are able to represent, to a good extent, the chemistry of photochemical smog. However, due to the large amount of computer resources required by these models, different well-known approaches have been used in order to make them operative. In any of these approaches, a set of educated guesses is made, based upon the knowledge of the conditions under which the reactions occur and the competition between them, and upon the expected absolute and relative concentrations of the emitted reactive organic gases (ROG). Are those educated guesses applicable to Mexico City? Do we know enough how the prevalent conditions of temperature, total pressure, ultraviolet irradiation and water content in the atmosphere operate over the chemistry of photochemical smog? An answer to these questions has been attempted by performing variational analysis of selected hydrocarbons. Some results for n-butane, propene and trans-2-butene are shown; they show that under conditions of high reactivity, some assumptions may not be applicable to Mexico City. Also, the results serve to show the applicability of the method to preliminary reactivity studies.

  20. Uncatalyzed thermal gas phase aziridination of alkenes by organic azides. Part I: Mechanisms with discrete nitrene species

    Indian Academy of Sciences (India)

    S PREMILA DEVI; TEJESHWORI SALAM; R H DUNCAN LYNGDOH

    2016-05-01

    Alkene aziridination by azides through uncatalyzed thermal gas phase routes has been studiedusing the DFT B3LYP/6-31G(d,p) method, where the possible role of discrete nitrene intermediates is emphasized.The thermal decomposition of azides is studied using the MP2/aug-cc-pVDZ strategy as well. The MP2(but not the B3LYP) results discount the existence of singlet alkylnitrenes where the alkyl group has an α-hydrogen. Addition of the lowest lying singlet and triplet nitrenes R-N (R = H, Me, Ac) to four different alkenesubstrates leading to aziridine formation was studied by the B3LYP method. Singlet nitrenes with alkenes canyield aziridines via a concerted mechanism, where H-N insertion takes place without a barrier, whereas Me-Nshows larger barriers than Ac-N. Methyl substitution in the alkene favors this reaction. Triplet nitrene additionto alkenes is studied as a two-step process, where the initially formed diradical intermediates cyclize to formaziridines by ISC (intersystem crossing) and collapse. Scope for C-C bond rotation in the diradical leads to lossof stereochemical integrity for triplet nitrene addition to cis- and trans-2-butenes. Geometries of the transitionstates in the various reaction steps studied here are described as “early” or “late” in good accordance with theHammond postulate.

  1. Oxidative Dehydrogenation of n-Butane over LaV Catalysts Supported on TiO2

    Directory of Open Access Journals (Sweden)

    Le Minh Cam

    2013-01-01

    Full Text Available The catalytic performance of vanadia catalysts with 15 wt% V supported on TiO2 and (15 wt% V + 4.6 wt% La supported on TiO2 in oxidative dehydrogenation (ODH of n-butane was investigated. The catalysts were characterized by means of TPD-NH3, TPR-H2, UV-Vis, and BET. Testing of samples showed that vanadia catalysts were active for the reaction. It was found that La doping of V/TiO2 catalyst had a negative effect on the dispersion of V species and led to formation of V2O5 clusters. This resulted in a loss of activity. Although slight improvement of selectivity was observed in comparison to undoped V/TiO2 samples due to lower acidity of La-doped –V/TiO2, this could not compensate the loss of activity and finally did not lead to higher butene yields.

  2. Characterisation of the acidity and the basicity of transition alumina by NMR and FTIR spectroscopy of adsorption of probe molecules; Caracterisation par RMN et infrarouge de molecules sondes adsorbees, de l'acidite et de la basicite d'alumines de transition

    Energy Technology Data Exchange (ETDEWEB)

    Mathonneau, E.

    2003-04-01

    This work has been devoted to characterization of the acidity and the basicity of the surface of transition alumina. Three different alumina (Alumina-{gamma}, -{delta} et -{theta} ({gamma}-Al, {delta}-Al, {theta}-Al)) have been studied by adsorption of probe molecules such trimethyl phosphine and carbon monoxide (acidity study); and tri-ethyl borane (basicity study). We emphasized that the acidity increases with an increasing pretreatment temperature where as the basicity decreases. Comparing quantitative results from the different probe molecules we could show an increasing strength acidity following: {gamma}-Al > {theta}-Al > {delta}-Al, and basicity following: {delta}-Al > {gamma}-Al > {theta}-Al. We could evaluate on a qualitative (nature and repartition) and on a quantitative point of view the impact of the transformations {gamma}-Al {yields} {delta}-Al and {gamma}-Al > {theta}-Al on the acid-basicity of the surface. We could also explain catalytic reactivity differences between alumina for the position isomerization of butene-1. (author)

  3. Influence of ethanol-gasoline blended fuel on emission characteristics from a four-stroke motorcycle engine.

    Science.gov (United States)

    Jia, Li-Wei; Shen, Mei-Qing; Wang, Jun; Lin, Man-Qun

    2005-08-31

    Emission characteristics from a four-stroke motorcycle engine using 10% (v/v) ethanol-gasoline blended fuel (E10) were investigated at different driving modes on the chassis dynamometers. The results indicate that CO and HC emissions in the engine exhaust are lower with the operation of E10 as compared to the use of unleaded gasoline, whereas the effect of ethanol on NO(X) emission is not significant. Furthermore, species of both unburned hydrocarbons and their ramifications were analyzed by the combination of gas chromatography/mass spectrometry (GC/MS) and gas chromatography/flame ionization detection (GC/FID). This analysis shows that aromatic compounds (benzene, toluene, xylene isomers (o-xylene, m-xylene and p-xylene), ethyltoluene isomers (o-ethyltoluene, m-ethyltoluene and p-ethyltoluene) and trimethylbenzene isomers (1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene and 1,3,5-trimethylbenzene)) and fatty group ones (ethylene, methane, acetaldehyde, ethanol, butene, pentane and hexane) are major compounds in motorcycle engine exhaust. It is found that the E10-fueled motorcycle engine produces more ethylene, acetaldehyde and ethanol emissions than unleaded gasoline engine does. The no significant reduction of aromatics is observed in the case of ethanol-gasoline blended fuel. The ethanol-gasoline blended fuel can somewhat improve emissions of the rest species.

  4. Direct Dehydrogenation of n-Butane Over Pt/Sn/Zn-K/Al2O3 Catalyst: Effect of Hydrogen in the Feed.

    Science.gov (United States)

    Lee, Jong Kwon; Seo, Hyun; Kim, Jeong Kwon; Seo, Hanuk; Cho, Hye-Ran; Lee, Jinsuk; Chang, Hosik; Song, In Kyu

    2016-05-01

    Al2O3 was prepared by a sol-gel method for use as a support. Pt/Sn/Zn-K/Al2O3 catalyst was then prepared by a sequential impregnation method, and it was applied to the direct dehydrogenation of n-butane to n-butenes and 1,3-butadiene. Physicochemical properties of Pt/Sn/Zn-K/Al2O3 catalyst were examined by X-ray diffraction (XRD), nitrogen adsorption-desorption isotherm, inductively coupled plasma atomic emission spectroscopy (ICP-AES), temperature-programmed reduction (TPR), CO chemisorption, and temperature-programmed oxidation (TPO) measurements. In order to improve the catalyst stability, the effect of hydrogen in the feed on the catalytic performance in the direct dehydrogenation of n-butane was studied. The catalyst stability and reusability in the direct dehydrogenation of n-butane was also investigated. Experimental results revealed that the addition of hydrogen in the feed decreased conversion of n-butane and yield for total dehydrogenation products but improved the stability of the catalyst. The catalytic activity and stability of regenerated Pt/Sn/Zn-K/Al2O3 catalyst in the presence of hydrogen slightly decreased compared to those of fresh Pt/Sn/Zn-K/Al2O3 catalyst due to the slight sintering of platinum particles. PMID:27483794

  5. A study of ethanol reactions on O2-treated Au/TiO2. Effect of support and metal loading on reaction selectivity

    Science.gov (United States)

    Nadeem, M. A.; Waterhouse, G. I. N.; Idriss, H.

    2016-08-01

    The reactions of ethanol have been studied on bare and Au supported TiO2 polymorphs (anatase and rutile) in order to understand the effect of Au loading and prior O2 treatment on the reaction selectivity and conversion using temperature programmed desorption (TPD). Although O2 treatment has negligible effect on the reaction selectivity of ethanol on TiO2 alone it considerably affects the reaction on Au/TiO2. Au/TiO2 had three main effects on the reaction when compared to TiO2 alone. First, it switches the reaction selectivity of the dehydration (to ethylene) in favor of dehydrogenation (to acetaldehyde) on both polymorphs. Second, it decreases the desorption temperature of the main reaction products. Third, it increases secondary reaction products (mainly C4 (crotonaldehyde, butene, furan) reaching ca. 78% of the overall carbon selectivity for the 8 wt.% Au/TiO2 anatase. These effects are more pronounced on the anatase phase when compared to that on the rutile phase. Reasons for these are discussed.

  6. Emissions of C2 - C12 hydrocarbons in the Hsuehshan tunnel, Taiwan

    Institute of Scientific and Technical Information of China (English)

    Chia-Hsiang Lai; Yen-Ping Peng

    2011-01-01

    The concentrations of 56 hydrocarbons from C2 to C12 were measured simultaneously in the southbound bore, the northbound bore and the exhaust air shafts of the Hsuehshan tunnel near Yilan, Taiwan for 12 days during 2007 and 2008.A total of 60 integrated air samples were collected using stainless steel canisters and analyzed using GC/FID and GC/MS.The five most abundant species in all samples were ethylene, acetylene, isopentane, propylene and toluene.The exit/entrance ratios of total non-methane hydrocarbons (NMHC) concentration were 7.8 and 4.8 for the southbound and northbound bores, respectively.Furthermore, the exhaust from the vertical shafts affects air quality in the neighborhood.The most abundant species of emission rate (ER) was toluene (21.93-42.89 mg/sec), followed by isopentane, ethylene, propylene and l~butene, with ER ranging from 2.50 to 9.31 mg/sec.The species in the three exhaust air shafts showed that the reacfivifies of these emissions are similar to those of vehicle emissions.Notably, the control of emissions in the vertical shafts of the vehicle tunnel will be important in the future.

  7. Effects of rf power on chemical composition and surface roughness of glow discharge polymer films

    Science.gov (United States)

    Zhang, Ling; He, Xiaoshan; Chen, Guo; Wang, Tao; Tang, Yongjian; He, Zhibing

    2016-03-01

    The glow discharge polymer (GDP) films for laser fusion targets were successfully fabricated by plasma enhanced chemical vapor deposition (PECVD) at different radio frequency (rf) powers. The films were deposited using trans-2-butene (T2B) mixed with hydrogen as gas sources. The composition and state of plasma were diagnosed by quadrupole mass spectrometer (QMS) and Langmuir probe during the deposition process. The composition, surface morphology and roughness were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and white-light interferometer (WLI), respectively. Based on these observation and analyses, the growth mechanism of defects in GDP films were studied. The results show that, at low rf power, there is a larger probability for secondary polymerization and formation of multi-carbon C-H species in the plasma. In this case, the surface of GDP film turns to be cauliflower-like. With the increase of rf power, the degree of ionization is high, the relative concentration of smaller-mass hydrocarbon species increases, while the relative concentration of larger-mass hydrocarbon species decreases. At higher rf power, the energy of smaller-mass species are high and the etching effects are strong correspondingly. The GDP film's surface roughness shows a trend of decrease firstly and then increase with the increasing rf power. At rf power of 30 W, the surface root-mean-square roughness (Rq) drops to the lowest value of 12.8 nm, and no "void" defect was observed.

  8. Studies on the effects of rapeseed meal on thyroid status of cattle, glucosinolate and iodine content of milk and other parameters.

    Science.gov (United States)

    Papas, A; Ingalls, J R; Campbell, L D

    1979-07-01

    The effects of feeding rapeseed meals (RSM) containing low (Tower) or high (Target/Turret) levels of glucosinolates on thyroid status, iodine and glucosinolate content of milk and other parameters were studied in dairy cows and young calves. RSM (Tower and Turret) fed to dairy cows at 25% of the grain mixture reduced iodine content of milk. Diets containing Tower and Turret RSM tended to reduce plasma thyroxine (T4) in cows and increase the size of thyroids in rats. Calf diets containing Target and Tower RSM resulted in increased liver and thyroid weights, but only those containing Target tended to reduce plasma T4 levels. Feed intake, weight gain, hemoglobin, blood cell volume and erythrocyte count in calves were not affected by diets containing Tower RSM, but Target RSM reduced all these parameters. In addition, diets containing Target caused more pronounced histological changes of the calves' thyroid than those containing Tower RSM. No measurable amounts of intact glucosinolates were detected in milk of cows fed RSM. Similarly the glucosinolate aglucones, isothiocyanates or vinyl oxazolidinethione, were not transferred to milk although small amounts of unsaturated nitrile (1-cyano-2-hydroxy-3-butene) and inorganic thiocyanate were detected in milk. Rats receiving milk from cows fed Turret RSM developed larger thyroid than those receiving milk from control-fed cows. Supplemental iodine (61.0 microgram/d) in the rat prevented the thyroid enlargement.

  9. {alpha}-Sb{sub 2}O{sub 4}-induced improvements of the catalytic behavior of MoO{sub 3}-(010) in the oxygen-assisted dehydration of 2-butanol: implications in selective oxidation

    Energy Technology Data Exchange (ETDEWEB)

    Gaigneaux, E.M. [Fonds National de la Recherche Scientifique of Belgium (Belgium); Naeye, M.L.; Dupont, O.; Ruiz, P.; Delmon, B. [Unite de Catalyse et Chimie des Materiaux Divises, Universite Catholique de Louvain, Louvain-La-Neuve (Belgium); Callant, M.; Kartheuser, B. [CERTECH, Senefffe (Belgium)

    1998-12-31

    This article concerns the synergetic effects between an MoO{sub 3} sample composed of crystallites exposing preferentially the (010) basal faces and {alpha}-Sb{sub 2}O{sub 4} in the oxygen-assisted dehydration of 2-butanol at 220 C. The conversion of 2-butanol and the yield to butene improved when MoO{sub 3} was reacted in the presence of {alpha}-Sb{sub 2}O{sub 4}. The origin of the synergism is discussed. When reacted in the absence of {alpha}-Sb{sub 2}O{sub 4}, MoO{sub 3} got over-reduced and fragmented to MoO{sub 2}. MoO{sub 2} is intrinsically less active than MoO{sub 3} thus explaining that the deep reduction of MoO{sub 3} corresponds to its tendency to deactivate. In the presence of {alpha}-Sb{sub 2}O{sub 4}, the formation of MoO{sub 2} is inhibited with, as a consequence, the absence of deactivation. This leads to the synergetic effects obtained with the mechanical mixture of MoO{sub 3} with {alpha}-Sb{sub 2}O{sub 4}. (orig.)

  10. Tracking Rh atoms in Zeolite HY: First Steps of Metal Cluster Formation and Influence of Metal Nuclearity on Catalysis of Ethylene Hydrogenation and Ethylene Dimerization

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Dong; Xu, Pinghong; Browning, Nigel D.; Gates, Bruce C.

    2016-07-07

    The initial steps of rhodium cluster formation from zeolite-supported mononuclear Rh(C2H4)2 complexes in H2 at 373 K and 1 bar were investigated by infrared and extended X-ray absorption fine structure spectroscopies and scanning transmission electron microscopy (STEM). The data show that ethylene ligands on the rhodium react with H2 to give supported rhodium hydrides and trigger the formation of rhodium clusters. STEM provided the first images of the smallest rhodium clusters (Rh2) and their further conversion into larger clusters. The samples were investigated in a plug-flow reactor as catalysts for the conversion of ethylene + H2 in a molar ratio of 4:1 at 1 bar and 298 K, with the results showing how the changes in catalyst structure affect the activity and selectivity; the rhodium clusters are more active for hydrogenation of ethylene than the single-site complexes, which are more selective for dimerization of ethylene to give butenes

  11. An estimate of the chemical composition of Titan's lakes

    CERN Document Server

    Cordier, D; Lunine, J -I; Lavvas, P; Vuitton, V

    2009-01-01

    Hundreds of radar-dark patches interpreted as lakes have been discovered in the north and south polar regions of Titan. We have estimated the composition of these lakes by using the direct abundance measurements from the Gas Chromatograph Mass Spectrometer (GCMS) aboard the Huygens probe and recent photochemical models based on the vertical temperature profile derived by the Huygens Atmospheric Structure Instrument (HASI). Thermodynamic equilibrium is assumed between the atmosphere and the lakes, which are also considered as nonideal solutions. We find that the main constituents of the lakes are ethane (C2H6) (~76-79%), propane (C3H8) (~7-8%), methane (CH4) (~5-10%), hydrogen cyanide (HCN) (~2-3%), butene (C4H8) (~1%), butane (C4H10) (~1%) and acetylene (C2H2) (~1%). The calculated composition of lakes is then substantially different from what has been expected from models elaborated prior to the exploration of Titan by the Cassini-Huygens spacecraft.

  12. Rich methane laminar flames doped with light unsaturated hydrocarbons. Part II: 1,3butadiene

    CERN Document Server

    Gueniche, Hadj-Ali; Fournet, René; Battin-Leclerc, Frédérique

    2007-01-01

    In line with the study presented in the part I of this paper, the structure of a laminar rich premixed methane flame doped with 1,3-butadiene has been investigated. The flame contains 20.7% (molar) of methane, 31.4% of oxygen and 3.3% of 1,3-butadiene, corresponding to an equivalence ratio of 1.8, and a ratio C4H6 / CH4 of 16 %. The flame has been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The temperature ranged from 600 K close to the burner up to 2150 K. Quantified species included usual methane C0-C2 combustion products and 1,3-butadiene, but also propyne, allene, propene, propane, 1,2-butadiene, butynes, vinylacetylene, diacetylene, 1,3-pentadiene, 2-methyl-1,3-butadiene (isoprene), 1-pentene, 3-methyl-1-butene, benzene and toluene. In order to model these new results, some improvements have been made to a mechanism previously developed in our laboratory for the reactions of C3-C4 unsaturated hydrocarbons. The main reacti...

  13. Rich methane laminar flames doped with light unsaturated hydrocarbons. Part III : cyclopentene

    CERN Document Server

    Gueniche, Hadj-Ali; Fournet, René; Battin-Leclerc, Frédérique

    2008-01-01

    In line with the studies presented in the parts I and II of this paper, the structure of a laminar rich premixed methane flame doped with cyclopentene has been investigated. The gases of this flame contains 15.3% (molar) of methane, 26.7% of oxygen and 2.4% cyclopentene corresponding to an equivalence ratio of 1.79 and a ratio C5H8 / CH4 of 16 %. The flame has been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The temperature ranged from 627 K close to the burner up to 2027 K. Quantified species included usual methane C0-C2 combustion products, but also propyne, allene, propene, propane, 1-butene, 1,3-butadiene, 1,2-butadiene, vinylacetylene, diacetylene, cyclopentadiene, 1,3-pentadiene, benzene and toluene. A new mechanism for the oxidation of cyclopentene has been proposed. The main reaction pathways of consumption of cyclopentene and of formation of benzene and toluene have been derived from flow rate analyses.

  14. Emission characteristics of volatile organic compounds from coal-, coal gangue-, and biomass-fired power plants in China

    Science.gov (United States)

    Yan, Yulong; Yang, Chao; Peng, Lin; Li, Rumei; Bai, Huiling

    2016-10-01

    Face the large electricity demand, thermal power generation still derives the main way of electricity supply in China, account for 78.19% of total electricity production in 2013. Three types of thermal power plants, including coal-fired power plant, coal gangue-fired power plant and biomass-fired power plant, were chosen to survey the source profile, chemical reactivity and emission factor of VOCs during the thermal power generation. The most abundant compounds generated during coal- and coal gangue-fired power generation were 1-Butene, Styrene, n-Hexane and Ethylene, while biomass-fired power generation were Propene, 1-Butenen, Ethyne and Ethylene. The ratios of B/T during thermal power generation in this study was 0.8-2.6, which could be consider as the characteristics of coal and biomass burning. The field tested VOCs emission factor from coal-, coal gangue- and biomass-fired power plant was determined to be 0.88, 0.38 and 3.49 g/GJ, or showed as 0.023, 0.005 and 0.057 g/kg, with the amount of VOCs emission was 44.07, 0.08, 0.45 Gg in 2013, respectively. The statistical results of previous emission inventory, which calculated the VOCs emission used previous emission factor, may overestimate the emission amount of VOCs from thermal power generation in China.

  15. Contribution from biogenic organic compounds to particle growth during the 2010 BEACHON-ROCS campaign in a Colorado temperate needle leaf forest

    Directory of Open Access Journals (Sweden)

    L. Zhou

    2015-03-01

    Full Text Available New particle formation (NPF is an important atmospheric phenomenon. During a NPF event, molecular clusters first form by nucleation and then grow further by condensation of vapors. The growth step is crucial because it controls the number of particles that can become cloud condensation nuclei. In order to better understand the influence of biogenic emissions on particle growth, we carried out modeling studies of NPF events during the BEACHON-ROCS campaign at Manitou Experimental Forest Observatory in Colorado, USA. The site is representative of the semi-arid Western US. The implemented chemistry scheme with the latest Criegee intermediates reaction rates underestimates sulfuric acid concentration by 50%, suggesting missing atmospheric sulfuric acid sources. The results emphasize the contribution from biogenic volatile organic compound emissions to particle growth by demonstrating the effects of the oxidation products of monoterpenes and 2-Methyl-3-buten-2-ol (MBO. Monoterpene oxidation products are shown to influence the nighttime particle loadings significantly while their concentrations are insufficient to grow the particles during the day. The growth of ultrafine particles in daytime appears to be closely related to the OH oxidation products of MBO.

  16. Thermal chemistry of copper(I)-N,N '-di-sec-butylacetamidinate on Cu(110) single-crystal surfaces

    International Nuclear Information System (INIS)

    The surface chemistry of copper(I)-N,N'-di-sec-butylacetamidinate on Cu(110) single-crystal surfaces has been characterized under ultrahigh vacuum by temperature programmed desorption (TPD) and X-ray photoelectron spectroscopy. A series of thermal stepwise conversions were identified, starting with the partial dissociative adsorption of the copper acetamidinate dimers into a mixture of monomers and dimers on the surface. An early dissociation of a C-N bond leads to the production of N-sec-butylacetamidine, which is detected in TPD experiments in three temperature regimes, the last one centered around 480 K. Butene, and a small amount of butane, is also detected above approximately 500 K, and hydrogen production, an indication of dehydrogenation of surface fragments, is observed at 460, 550 and 670 K. In total, only about 10% of the initial copper(I)-N,N'-di-sec-butylacetamidinate adsorbed monolayer decomposes, and only about ∼3% of carbon is left behind on the surface after heating to high temperatures. The implications of this surface chemistry to the design of chemical film growth processes using copper acetamidinates as precursors are discussed.

  17. Evaluation of Ferrocene Derivatives as Burn Rate Modifiers in AP/HTPB-Based Composite Propellants

    Directory of Open Access Journals (Sweden)

    G. M. Gore

    1999-04-01

    Full Text Available Some ferrocene derivatives like 2,4-dinitrophenylhydrazine derivative of acetyl ferrocene, 1-pyrrolidinylmethyl ferrocene, di-ter-butyl ferrocene and 1,3-diferrocenyl-l-butene (DFB have been synthesised and characterised by infrared, nuclear magnetic resonance, ultraviolet, iron content, etc. To study the effect of their incorporation on performance, ammonium perchlorate/hydroxyl-terminated polybutadiene-based composite propellants containing these derivatives have been prepared and studied for burn rates, tensile strength and percentage elongation followed by their static test evaluation. A comparison of the properties of propellant containing solid and liquid ferrocene derivatives has been made with those containing Fe/sub 2/O/sub 3/ and n-butyl ferrocene, respectively. The data clearly indicates that these ferrocene derivatives are better than Fe/sub 2/O/sub 3/ and n-butyl errocene. Also, DFB is the best among these derivatives. Like composite propellants, DFB increases burn rate in fuel-rich propellants also.

  18. Probing the kinetics for thiol desulfurization: The reactions of 2-methyl-2-propanethiol on Mo(110)

    Energy Technology Data Exchange (ETDEWEB)

    Wiegand, B.C.; Uvdal, P.; Friend, C.M. [Harvard Univ., Cambridge, MA (United States)

    1992-05-28

    The reactions of 2-methyl-2-propanethiol on Mo(110) were studied using temperature programmed reaction, high resolution electron energy loss, and X-ray photoelectron spectroscopies. The sulfur-hydrogen bond breaks upon adsorption at 120 K, yielding adsorbed 2-methyl-2-propyl thiolate and hydrogen. Thiolate hydrogenolysis produces isobutane, while cleavage of the C-S and selective C-H bond breaking {beta} to the sulfur yields isobutene. Nonselective decomposition to adsorbed carbon, sulfur, and gaseous dihydrogen is a competing channel. At reaction saturation, the selectivity for hydrocarbon for hydrocarbon formation patterns is 80%. The specific butane and butene isomers were identified on the basis of the differences in the fragmentation patterns of the various isomers when an electron energy of 27 eV was used in the mass spectrometer. The isometric selectivity corroborates the authors general mechanism for thiolate reaction. Isobutane formation preceded ethane formation for a 2-methyl-2-propanethiol/ethanethiol mixture. The kinetics for 2-methyl-2-propyl thiolate desulfurization were found to increase with increasing 2-methyl-2-propyl thiolate coverage. 38 refs., 6 figs., 4 tabs.

  19. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Science.gov (United States)

    Bouvier-Brown, N. C.; Goldstein, A. H.; Worton, D. R.; Matross, D. M.; Gilman, J. B.; Kuster, W. C.; Welsh-Bon, D.; Warneke, C.; de Gouw, J. A.; Cahill, T. M.; Holzinger, R.

    2009-03-01

    We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments - a gas chromatograph with mass spectrometer detector (GC-MS), a proton transfer reaction mass spectrometer (PTR-MS), and a thermal desorption aerosol GC-MS (TAG) - and found to be abundant within and above Blodgett Forest. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO), a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4-68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72-10.2 μgCg-1 h-1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde) in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  20. Virtual disjunct eddy covariance measurements of organic compound fluxes from a subalpine forest using proton transfer reaction mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. G. Karl

    2002-07-01

    Full Text Available A `virtual' disjunct eddy covariance (vDEC device was tested with field measurements of biogenic VOC fluxes at a subalpine forest site in the Rocky Mountains of the U.S.A. A PTR-MS instrument was used as the VOC sensor. Daily peak emission fluxes of 2-methyl-3-buten-2-ol (MBO, methanol, acetone and acetaldehyde were around 1.5, 1, 0.8 and 0.4 mg m-2 h-1, respectively. High pass filtering due to long sampling lines was investigated in laboratory experiments, and suggested that VOC losses in PTFA lines are generally governed by diffusion laws. Memory effects and surface reactions did not seem to play a dominant role. Model estimates of MBO fluxes compared well with measured fluxes. The results also suggest that latent heat and sensible heat fluxes are reasonably well correlated with VOC fluxes and could be used to predict variations in VOC emissions. The release of MBO, methanol, acetone and acetaldehyde resulted in significant change of tropospheric oxidant levels and a 10--40% increase in ozone levels, as inferred from a photochemical box model. We conclude that vDEC with a PTR-MS instrument is a versatile tool for simultaneous field analysis of multiple VOC fluxes.

  1. Conformational Analysis of 1-ALKENE Secondary Ozonides by Means of Matrix Isolation FTIR Spectroscopy

    Science.gov (United States)

    Sablinskas, Valdas; Strazdaite, Simona; Ceponkus, Justinas

    2009-06-01

    An ability of ozone to break double C=C bond in olefins is known for more than five decades. Understanding of those reactions is very important in atmospheric chemistry. During different steps of the reaction the primary ozonide (POZ), carbonyl oxide (COX) and the secondary ozonide (SOZ) are formed. Fate of the reaction depends on many parameters such as type of radical, conformation of alkene, temperature of the reaction and environmental effects. Despite of numerous studies of the reaction by different spectroscopic techniques the precise mechanism of the reaction is still unknown. It is experimentally observed that the SOZ is more stable than POZ. Stability of the SOZ depends on the size and configuration of the radical. Unfortunately, it is not much known about the spatial structures of the SOZ'es. The aim of this study is to define the geometrical structures and stability of the different conformers of the 1-butene and 1-heptene secondary ozonides by combined analysis of the matrix isolation FTIR spectral data with the results of Density Functional Theory (DFT) calculations.

  2. Physicochemical Features of Phosphorus-Modified ZSM-5 Zeolite and Its Performance on Catalytic Pyrolysis to Produce Ethylene%磷改性ZSM-5分子筛物化性质和裂解制乙烯性能的研究

    Institute of Scientific and Technical Information of China (English)

    柯明; 汪燮卿; 张凤美

    2003-01-01

    The physicochemical features of phosphorus-modified ZSM-5 zeolites (SiO2/Al2O3 molar ratio is 25)were characterized by XRD(X-ray diffraction), BET(Brunauer, Emmett and Teller spcific surface area measurement), NH3-TPD(ammonia temperature-programmed desorption) and MASNMR(magic angle spinning nuclear magnetic resonance), and the performance on catalytic pyrolysis to produce ethylene was investigated with a light hydrocarbon fixed bed micro-reactor with n-octane as feed. The results show that the acid site density, acid intensity and hydrothermal stability of ZSM-5 zeolite were improved by phosphorus modification. When P2O5 content in ZSM-5 zeolite is higher than 2.5%, phosphorus modification can prevent ZSM-5 zeolite crystal structure transformation from orthorhombic to monoclinic. In addition, the dealumination of ZSM-5 zeolite framework was moderated by phosphorus modification under high temperature hydrothermal treatment. The results of n-octane pyrolysis on phosphorus-modified ZSM-5 zeolites show that ethylene yields of zeolites with different phosphorus content are almost the same under the same n-octane conversion. However, the modified zeolites with higher pyrolysis activity give lower yield of propene, butene and total olefin than lower pyrolysis activity under the same n-octane conversion.

  3. Physicochemical Features of Phosphorus-Modified ZSM-5 Zeolite and Its Performance on Catalytic Pyrolysis to Produce Ethylene

    Institute of Scientific and Technical Information of China (English)

    柯明; 汪燮卿; 张凤美

    2003-01-01

    The physicochemical features of phosphorus-modified ZSM-5 zeolites (SiO2/Al2O3 molar ratio is 25) were characterized by XRD(X-ray diffraction), BET(Brunauer, Emmett and Teller spcific surface area measurement), NH3-TPD(ammonia temperature-programmed desorption) and MASNMR(magic angle spinning nuclear magnetic resonance), and the performance on catalytic pyrolysis to produce ethylene was investigated with a light hydrocarbon fixed bed micro-reactor with n-octane as feed. The results show that the acid site density, acid intensity and hydrothermal stability of ZSM-5 zeolite were improved by phosphorus modification. When P205 content in ZSM-5 zeolite is higher than 2.5%, phosphorus modification can prevent ZSM-5 zeolite crystal structure transformation from orthorhombic to monoclinic. In addition, the dealumination of ZSM-5 zeolite framework was moderated by phosphorus modification under high temperature hydrothermal treatment. The results of n-octane pyrolysis on phosphorus-modified ZSM-5 zeolites show that ethylene yields of zeolites with different phosphorus content are almost the same under the same n-octane conversion. However, the modified zeolites with higher pyrolysis activity give lower yield of propene, butene and total olefin than lower pyrolysis activity under the same n-octane conversion.

  4. IMPACT OF AIRCRAFT TRAFFIC EMISSIONS ON OZONE FORMATION AT THE RIO DE JANEIRO URBAN AREA

    Directory of Open Access Journals (Sweden)

    Guimarães, C.S., Arbilla, G., Corrêa, S.M., Gatti, L.V.

    2007-01-01

    Full Text Available Data for speciated volatile organic compounds (VOC evaluated in Santos-Dumont Airport and Antonio Carlos Jobim International Airport in Rio de Janeiro, Brazil, are reported. VOC were evaluated by gas chromatography with flame ionization detection (GC – FID and mass spectrometry (GC – MS, following the U.S. EPA TO – 15 methodology. At Santos-Dumont Airport were quantified 1376 µg m-3 of VOCs 10 m from runway, 408 µg m-3 inside the airport building, and 116 µg m-3 outside the airport area. At the taxiway area of the International Airport a total of 190 µg m-3 of VOC were quantified. Toluene, the most abundant compound near the Santos-Dumont Airport runway, was obtained in a non-significative concentration outside the airport area. This fact suggests that this area is not noticeably impacted by air traffic. A computational model was developed using the OZIPR program and the SAPRC mechanism. Calculated ozone concentrations are higher than values for downtown area of Rio de Janeiro city. Simulated results show that, for the runway in Santos-Dumont Airport, olefins and aromatics contribute in 57% and 15%, respectively, to ozone formation, toluene being the major contributor. Cis-2-butene is the most reactive species regarding OH reaction.

  5. Post-Polymerization Crosslinked Polyurethane Shape-Memory Polymers.

    Science.gov (United States)

    Hearon, K; Gall, K; Ware, T; Maitland, D J; Bearinger, J P; Wilson, T S

    2011-07-01

    Novel urethane shape-memory polymers (SMPs) of significant industrial relevance have been synthesized and characterized. Chemically crosslinked SMPs have traditionally been made in a one-step polymerization of monomers and crosslinking agents. However, these new post-polymerization crosslinked SMPs can be processed into complex shapes by thermoplastic manufacturing methods and later crosslinked by heat exposure or by electron beam irradiation. Several series of linear, olefinic urethane polymers were made from 2-butene-1,4-diol, other saturated diols, and various aliphatic diisocyanates. These thermoplastics were melt-processed into desired geometries and thermally crosslinked at 200°C or radiation crosslinked at 50 kGy. The SMPs were characterized by solvent swelling and extraction, differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), tensile testing, and qualitative shape-recovery analysis. Swelling and DMA results provided concrete evidence of chemical crosslinking, and further characterization revealed that the urethanes had outstanding mechanical properties. Key properties include tailorable transitions between 25 and 80°C, tailorable rubbery moduli between 0.2 and 4.2 MPa, recoverable strains approaching 100%, failure strains of over 500% at T(g), and qualitative shape-recovery times of less than 12 seconds at body temperature (37°C). Because of its outstanding thermo-mechanical properties, one polyurethane was selected for implementation in the design of a complex medical device. These post-polymerization crosslinked urethane SMPs are an industrially relevant class of highly processable shape-memory materials.

  6. Virtual disjunct eddy covariance measurements of organic compound fluxes from a subalpine forest using proton transfer reaction mass spectrometry

    Directory of Open Access Journals (Sweden)

    T. G. Karl

    2002-01-01

    Full Text Available A `virtual' disjunct eddy covariance (vDEC device was tested with field measurements of biogenic VOC fluxes at a subalpine forest site in the Rocky Mountains of the USA. A PTR-MS instrument was used as the VOC sensor. Daily peak emission fluxes of 2-methyl-3-buten-2-ol (MBO, methanol, acetone and acetaldehyde were around 1.5, 1, 0.8 and 0.4 mg m-2 h-1, respectively. High pass filtering due to long sampling lines was investigated in laboratory experiments, and suggested that VOC losses in PTFA lines are generally governed by diffusion laws. Memory effects and surface reactions did not seem to play a dominant role. Model estimates of MBO fluxes compared well with measured fluxes. The results also suggest that latent heat and sensible heat fluxes are reasonably well correlated with VOC fluxes and could be used to predict variations in VOC emissions. The release of MBO, methanol, acetone and acetaldehyde resulted in significant change of tropospheric oxidant levels and a 10--40% increase in ozone levels, as inferred from a photochemical box model. We conclude that vDEC with a PTR-MS instrument is a versatile tool for simultaneous field analysis of multiple VOC fluxes.

  7. New analytical method for the determination of styrene oligomers formed from polystyrene decomposition and its application at the coastlines of the North-West Pacific ocean.

    Science.gov (United States)

    Saido, Katsuhiko; Koizumi, Koshiro; Sato, Hideto; Ogawa, Naoto; Kwon, Bum Gun; Chung, Seon-Yong; Kusui, Takashi; Nishimura, Masahiko; Kodera, Yoichi

    2014-03-01

    The pollution caused by plastic debris is an environmental problem with increasing concern in the oceans. Among the plastic polymers, polystyrene (PS) is one of the most problematic plastics due to the direct public health risk associated with their dispersion, as well as the numerous adverse environmental impacts which arise both directly from the plastics and from their degradation products. Little is known about their potential distribution characteristics throughout the oceans. For the first time, we report here on the regional distribution of styrene monomer (SM), styrene dimers (SD; 2,4-diphenyl-1-butene, SD1; 1,3-diphenyl propane, SD2), and styrene trimer (2,4,6-triphenyl-1-hexene: ST1), as products of PS decomposition determined from samples of sand and seawater from the shorelines of the North-West Pacific ocean. In order to quantitatively determine SM, SD (=SD1+SD2), and ST1, a new analytical method was developed. The detection limit was 3.3 μg L(-1), based on a signal-to-noise ratio of three, which was well-suited to quantify levels of SM, SD, and ST1 in samples. Surprisingly, the concentrations of SM, SD, and ST1 in sand samples from the shorelines were consistently greater than those in seawater samples from the same location. The results of this study suggest that SM, SD, and ST1 can be widely dispersed throughout the North-West Pacific oceans. PMID:24394362

  8. The nicotinic agonist RJR-2403 compensates the impairment of eyeblink conditioning produced by the noncompetitive NMDA-receptor antagonist MK-801.

    Science.gov (United States)

    Rodríguez-Moreno, Antonio; Carrión, Miriam; Delgado-García, José María

    2006-07-10

    The classical conditioning of eyelid responses using trace paradigms is a hippocampal-related model of associative learning, involving the activation of N-methyl-D-aspartate (NMDA) receptors. We have evaluated here the effects of NMDA-receptor blockage with the selective noncompetitive antagonist (5R,10S)-(+)-5-methyl-10,11-dihydro-5H-dibenzo[a,d]cyclohepten-5,10-imine hydrogen maleate (dizocilpine, MK-801). Mice were implanted with stimulating electrodes on the supraorbitary nerve and with recording electrodes in the ipsilateral orbicularis oculi muscle. Animals were conditioned with a trace shock-SHOCK paradigm. MK-801-injected animals (0.02 mg/kg) seemed unable to acquire this type of associative learning task, but the latency and amplitude of their unconditioned eyelid responses was not affected by drug administration. The administration of the nicotinic agonist (E)-N-methyl-4-(3-pyridinyl)-3-buten-1-amine (RJR-2403; 2 mg/kg) was able to restore completely the acquisition of the conditioned response when administered both before and after MK-801. In vitro recordings of field excitatory postsynaptic potentials (fEPSPs) evoked in the hippocampal CA1 area by the electrical stimulation of the Schaffer collateral pathway indicates that RJR-2403 application to the bath enhance the release of glutamate by a presynaptic mechanism. These findings reveal that nicotinic acetylcholine receptors enhance glutamatergic transmission in hippocampal circuits involved in the acquisition of associative learning.

  9. Tracking Rh Atoms in Zeolite HY: First Steps of Metal Cluster Formation and Influence of Metal Nuclearity on Catalysis of Ethylene Hydrogenation and Ethylene Dimerization.

    Science.gov (United States)

    Yang, Dong; Xu, Pinghong; Browning, Nigel D; Gates, Bruce C

    2016-07-01

    The initial steps of rhodium cluster formation from zeolite-supported mononuclear Rh(C2H4)2 complexes in H2 at 373 K and 1 bar were investigated by infrared and extended X-ray absorption fine structure spectroscopies and scanning transmission electron microscopy (STEM). The data show that ethylene ligands on the rhodium react with H2 to give supported rhodium hydrides and trigger the formation of rhodium clusters. STEM provided the first images of the smallest rhodium clusters (Rh2) and their further conversion into larger clusters. The samples were investigated in a plug-flow reactor as catalysts for the conversion of ethylene + H2 in a molar ratio of 4:1 at 1 bar and 298 K, with the results showing how the changes in catalyst structure affect the activity and selectivity; the rhodium clusters are more active for hydrogenation of ethylene than the single-site complexes, which are more selective for dimerization of ethylene to give butenes. PMID:27315020

  10. Comparative Metabolism of Furan in Rodent and Human Cryopreserved Hepatocytes

    Science.gov (United States)

    Gates, Leah A.; Phillips, Martin B.; Matter, Brock A.

    2014-01-01

    Furan is a liver toxicant and carcinogen in rodents. Although humans are most likely exposed to furan through a variety of sources, the effect of furan exposure on human health is still unknown. In rodents, furan requires metabolism to exert its toxic effects. The initial product of the cytochrome P450 2E1-catalyzed oxidation is a reactive α,β-unsaturated dialdehyde, cis-2-butene-1,4-dial (BDA). BDA is toxic and mutagenic and consequently is considered responsible for the toxic effects of furan. The urinary metabolites of furan in rats are derived from the reaction of BDA with cellular nucleophiles, and precursors to these metabolites are detected in furan-exposed hepatocytes. Many of these precursors are 2-(S-glutathionyl)butanedial-amine cross-links in which the amines are amino acids and polyamines. Because these metabolites are derived from the reaction of BDA with cellular nucleophiles, their levels are a measure of the internal dose of this reactive metabolite. To compare the ability of human hepatocytes to convert furan to the same metabolites as rodent hepatocytes, furan was incubated with cryopreserved human and rodent hepatocytes. A semiquantitative liquid chromatography with tandem mass spectrometry assay was developed for a number of the previously characterized furan metabolites. Qualitative and semiquantitative analysis of the metabolites demonstrated that furan is metabolized in a similar manner in all three species. These results indicate that humans may be susceptible to the toxic effects of furan. PMID:24751574

  11. Intrinsic catalytic properties of extruded clay honeycomb monolith toward complete oxidation of air pollutants.

    Science.gov (United States)

    Assebban, Mhamed; El Kasmi, Achraf; Harti, Sanae; Chafik, Tarik

    2015-12-30

    The present work highlights the intrinsic catalytic properties of extruded clay honeycomb monolith toward complete oxidation of various air pollutants namely CO, methane, propane, acetylene, propene, n-butene, methanol, ethanol, n-propanol, n-butanol, acetone, dimethyl ether, benzene, toluene, o-xylene, monochlorobenzene and 1,2-dichlorobenzene. Total catalytic conversion was achieved for all tested compounds with different behaviors depending on pollutants' structural and chemical nature. The comparison of T50 values obtained from light-off curves allowed the establishment of the following reactivity sequence: ketone>alcohol>ether>CO>alkyne>aromatic>alkene>chlorinated aromatic>alkane. The intrinsic catalytic performances of the natural clay was ascribed to the implication of a quite complex mixture constituted by OH groups (Brønsted acids) and coordinately-unsaturated cations, such as Al(3+), Fe(3+) and Fe(2+) (Lewis acids). Hence, the combination of the clay's intrinsic catalytic performances and easier extrudability suggests a promissory potential for application in air pollution control. PMID:26259164

  12. Polar organic marker compounds in atmospheric aerosols during the LBA-SMOCC 2002 biomass burning experiment in Rondônia, Brazil: sources and source processes, time series, diel variations and size distributions

    Directory of Open Access Journals (Sweden)

    M. Claeys

    2010-04-01

    Full Text Available Measurements of polar organic marker compounds were performed on aerosols that were collected at a pasture site in the Amazon basin (Rondônia, Brazil using a High-Volume dichotomous sampler (HVDS and a Micro-Orifice Uniform Deposit Impactor (MOUDI. The samplings were conducted within the framework of the LBA-SMOCC (Large-Scale Biosphere Atmosphere Experiment in Amazônia – Smoke Aerosols, Clouds, Rainfall, and Climate: Aerosols From Biomass Burning Perturb Global and Regional Climate campaign, which took place from 9 September till 14 November 2002, spanning the late dry season (biomass burning, the transition period, and the onset of the wet season (clean conditions. In the present study a more detailed discussion is presented compared to previous reports on the behavior of selected polar marker compounds, including: (a levoglucosan, a tracer for biomass burning, (b malic acid, a tracer for the oxidation of semivolatile carboxylic acids, (c tracers for secondary organic aerosol (SOA from isoprene, i.e., the 2-methyltetrols (2-methylthreitol and 2-methylerythritol and the C5-alkene triols [2-methyl-1,3,4-trihydroxy-1-butene (cis and trans and 3-methyl-2,3,4-trihydroxy-1-butene], and (d sugar alcohols (arabitol, mannitol, and erythritol, tracers for fungal spores. The results obtained for levoglucosan are covered first with the aim to address its contrasting behavior with that of malic acid, the isoprene SOA tracers, and the fungal spore tracers. The tracer data are discussed taking into account new insights that recently became available into their stability and/or aerosol formation processes. During all three periods, levoglucosan was the most dominant identified organic species in the PM2.5 size fraction of the HVDS samples. In the dry period levoglucosan reached concentrations of up to 7.5 μg m−3 and exhibited diel variations with a nighttime prevalence. It was closely associated with the

  13. Propriedades mecânicas e morfologia de blendas de polipropileno com Tpes Morphology and mechanical properties of polypropylenes/Tpes blends

    Directory of Open Access Journals (Sweden)

    Flávia O. M. S. Abreu

    2006-03-01

    Full Text Available Blendas de polipropileno e elastômeros termoplásticos (TPEs, estireno-b-butadieno-b-estireno (SBS e estireno-b-etileno-co-butileno-b-estireno(SEBS foram preparadas com o objetivo de avaliar a influência do tipo e da concentração do elastômero nas propriedades mecânicas e na morfologia das blendas. Foram utilizados dois tipos de polipropileno, um homopolímero de propileno (PP-H e um copolímero randômico de propileno-etileno (PP-R, sendo avaliado também o efeito das características da matriz termoplástica. O elastômero termoplástico aumentou a resistência ao impacto do PP, e a variação da rigidez das blendas foi dependente somente da quantidade de TPE adicionada, sendo estas comparativamente mais rígidas que aquelas com igual teor de elastômero convencional, tipo EPDM e EPR. A blenda com melhor balanço rigidez-impacto foi aquela de PP-R com 10% de SEBS. As blendas do copolímero de propileno-etileno com os TPEs apresentaram maior deformação do que aquelas com o homopolímero, devido à natureza menos cristalina da matriz do copolímero de propileno. As blendas tanto do homo quanto do copolímero de propileno com SEBS ficaram mais homogêneas em função da maior afinidade do bloco central poliolefínico EB (etileno-co-butileno do primeiro com a região amorfa da matriz, sendo esta mais significativa no PP-R.Blends of polypropylene and thermoplastic elastomers (TPEs of styrene-butadiene-styrene (SBS and styrene-ethylene-co-butene-styrene (SEBS triblock copolymers were prepared to evaluate the effect of the elastomer and its concentration on the material properties. For this purpose, a polypropylene homopolymer (PP-H and a propylene-ethylene random copolymer (PP-R were used to evaluate the matrix effect on the tensile properties and morphology of the blends. The addition of TPEs to PP promotes increase on impact resistance and the PP-R/SEBS 10%wt blend showed the best balance in stiffness-impact resistance. The morphology of

  14. Investigation of potential interferences in the detection of atmospheric ROx radicals by laser-induced fluorescence under dark conditions

    Science.gov (United States)

    Fuchs, Hendrik; Tan, Zhaofeng; Hofzumahaus, Andreas; Broch, Sebastian; Dorn, Hans-Peter; Holland, Frank; Künstler, Christopher; Gomm, Sebastian; Rohrer, Franz; Schrade, Stephanie; Tillmann, Ralf; Wahner, Andreas

    2016-04-01

    Direct detection of highly reactive, atmospheric hydroxyl radicals (OH) is widely accomplished by laser-induced fluorescence (LIF) instruments. The technique is also suitable for the indirect measurement of HO2 and RO2 peroxy radicals by chemical conversion to OH. It requires sampling of ambient air into a low-pressure cell, where OH fluorescence is detected after excitation by 308 nm laser radiation. Although the residence time of air inside the fluorescence cell is typically only on the order of milliseconds, there is potential that additional OH is internally produced, which would artificially increase the measured OH concentration. Here, we present experimental studies investigating potential interferences in the detection of OH and peroxy radicals for the LIF instruments of Forschungszentrum Jülich for nighttime conditions. For laboratory experiments, the inlet of the instrument was over flowed by excess synthetic air containing one or more reactants. In order to distinguish between OH produced by reactions upstream of the inlet and artificial signals produced inside the instrument, a chemical titration for OH was applied. Additional experiments were performed in the simulation chamber SAPHIR where simultaneous measurements by an open-path differential optical absorption spectrometer (DOAS) served as reference for OH to quantify potential artifacts in the LIF instrument. Experiments included the investigation of potential interferences related to the nitrate radical (NO3, N2O5), related to the ozonolysis of alkenes (ethene, propene, 1-butene, 2,3-dimethyl-2-butene, α-pinene, limonene, isoprene), and the laser photolysis of acetone. Experiments studying the laser photolysis of acetone yield OH signals in the fluorescence cell, which are equivalent to 0.05 × 106 cm-3 OH for a mixing ratio of 5 ppbv acetone. Under most atmospheric conditions, this interference is negligible. No significant interferences were found for atmospheric concentrations of reactants

  15. Oligomer formation during gas-phase ozonolysis of small alkenes and enol ethers: new evidence for the central role of the Criegee Intermediate as oligomer chain unit

    Directory of Open Access Journals (Sweden)

    A. Sadezky

    2008-05-01

    Full Text Available An important fraction of secondary organic aerosol (SOA formed by atmospheric oxidation of diverse volatile organic compounds (VOC has recently been shown to consist of high-molecular weight oligomeric species. In our previous study (Sadezky et al., 2006, we reported the identification and characterization of oligomers as main constituents of SOA from gas-phase ozonolysis of small enol ethers. These oligomers contained repeated chain units of the same chemical composition as the main Criegee Intermediates (CI formed during the ozonolysis reaction, which were CH2O2 (mass 46 for alkyl vinyl ethers (AVE and C2H4O2 (mass 60 for ethyl propenyl ether (EPE. In the present work, we extend our previous study to another enol ether (ethyl butenyl ether EBE and a variety of structurally related small alkenes (trans-3-hexene, trans-4-octene and 2,3-dimethyl-2-butene.

    Experiments have been carried out in a 570 l spherical glass reactor at atmospheric conditions in the absence of seed aerosol. SOA formation was measured by a scanning mobility particle sizer (SMPS. SOA filter samples were collected and chemically characterized off-line by ESI(+/TOF MS and ESI(+/TOF MS/MS, and elemental compositions were determined by ESI(+/FTICR MS and ESI(+/FTICR MS/MS. The results for all investigated unsaturated compounds are in excellent agreement with the observations of our previous study. Analysis of the collected SOA filter samples reveal the presence of oligomeric compounds in the mass range 200 to 800 u as major constituents. The repeated chain units of these oligomers are shown to systematically have the same chemical composition as the respective main Criegee Intermediate (CI formed during ozonolysis of the unsaturated compounds, which is C3H6O2 (mass 74 for ethyl butenyl ether (EBE, trans-3-hexene, and 2,3-dimethyl-2-butene, and C4H8

  16. Oligomer formation during gas-phase ozonolysis of small alkenes and enol ethers: new evidence for the central role of the Criegee Intermediate as oligomer chain unit

    Directory of Open Access Journals (Sweden)

    A. Sadezky

    2007-10-01

    Full Text Available An important fraction of secondary organic aerosol (SOA formed by atmospheric oxidation of diverse volatile organic compounds (VOC has recently been shown to consist of high-molecular weight oligomeric species. In our previous study (Sadezky et al., 2006, we reported the identification and characterization of oligomers as main constituents of SOA from gas-phase ozonolysis of small enol ethers. These oligomers contained repeated chain units of the same chemical composition as the main Criegee Intermediates (CI formed during the ozonolysis reaction, which were CH2O2 (mass 46 for alkyl vinyl ethers (AVE and C2H4O2 (mass 60 for ethyl propenyl ether (EPE. In the present work, we extend our previous study (Sadezky et al., 2006 to another enol ether (ethyl butenyl ether EBE and a variety of structurally related small alkenes (trans-3-hexene, trans-4-octene and 2,3-dimethyl-2-butene.

    Experiments have been carried out in a 570 l spherical glass reactor at atmospheric conditions in the absence of seed aerosol. SOA formation was measured by a scanning mobility particle sizer (SMPS. SOA filter samples were collected and chemically characterized off-line by ESI(+/MS-TOF and ESI(+/MS/MS-TOF, and elemental compositions were confirmed by ESI(+/MS/MS-FTICR. The results for all investigated unsaturated compounds are in excellent agreement with the observations of our previous study (Sadezky et al., 2006. Analysis of the collected SOA filter samples reveal the presence of oligomeric compounds in the mass range 200 to 800 u as major constituents. The repeated chain units of these oligomers are shown to systematically have the same chemical composition as the respective main Criegee Intermediate (CI formed during ozonolysis of the unsaturated compounds, which is C3H6O2 (mass 74 for ethyl butenyl ether (EBE, trans-3-hexene, and 2,3-dimethyl-2-butene

  17. Insights into functional-group-tolerant polymerization catalysis with phosphine-sulfonamide palladium (II) complexes

    KAUST Repository

    Jian, Zhongbao

    2014-12-08

    Two series of cationic palladium(II) methyl complexes {[(2-MeOC6H4)2PC6H4SO2NHC6H3(2,6-R1,R2)]PdMe}2[A]2 (X1+-A: R1=R2=H: H1+-A; R1=R2=CH(CH3)2: DIPP1+-A; R1=H, R2=CF3: CF31+-A; A=BF4 or SbF6) and neutral palladium(II) methyl complexes {[(2-MeOC6H4)2PC6H4SO2NC6H3(2,6-R1,R2)]PdMe(L)} (X1-acetone: L=acetone; X1-dmso: L=dimethyl sulfoxide; X1-pyr: L=pyridine) chelated by a phosphine-sulfonamide were synthesized and fully characterized. Stoichiometric insertion of methyl acrylate (MA) into all complexes revealed that a 2,1 regiochemistry dominates in the first insertion of MA. Subsequently, for the cationic complexes X1+-A, β-H elimination from the 2,1-insertion product X2+-AMA-2,1 is overwhelmingly favored over a second MA insertion to yield two major products X4+-AMA-1,2 and X5+-AMA. By contrast, for the weakly coordinated neutral complexes X1-acetone and X1-dmso, a second MA insertion of the 2,1-insertion product X2MA-2,1 is faster than β-H elimination and gives X3MA as major products. For the strongly coordinated neutral complexes X1-pyr, no second MA insertion and no β-H elimination (except for DIPP2-pyrMA-2,1) were observed for the 2,1-insertion product X2-pyrMA-2,1. The cationic complexes X1+-A exhibited high catalytic activities for ethylene dimerization, affording butenes (C4) with a high selectivity of up to 97.7% (1-butene: 99.3%). Differences in activities and selectivities suggest that the phosphine-sulfonamide ligands remain coordinated to the metal center in a bidentate fashion in the catalytically active species. By comparison, the neutral complexes X1-acetone, X1-dmso, and X1-pyr showed very low activity towards ethylene to give traces of oligomers. DFT analyses taking into account the two possible coordination modes (O or N) of the sulfonamide ligand for the cationic system CF31+ suggested that the experimentally observed high activity in ethylene dimerization is the result of a facile first ethylene insertion into the O-coordinated PdMe isomer and

  18. Energy barriers for the addition of H, *CH3, and *C2H5 to *CH2=CHX [X = H, CH3, OH] and for H-atom addition to RCH=O [R = H, CH3, *C2H5, n-C3H7]: implications for the gas-phase chemistry of enols.

    Science.gov (United States)

    Simmie, John M; Curran, Henry J

    2009-07-01

    Although enols have been identified in alcohol and other flames and in interstellar space and have been implicated in the formation of carboxylic acids in the urban troposphere in the past few years, the reactions that give rise to them are virtually unknown. To address this data deficit, particularly with regard to biobutanol combustion, we have carried out a number of ab initio calculations with the multilevel methods CBS-QB3 and CBS-APNO to determine the activation enthalpies for methyl addition to the CH(2) group of CH(2)=CHX where X = H, OH, and CH(3). These average at 26.3 +/- 1.0 kJ mol(-1) and are not influenced by the nature of X; addition to the CHX end is energetically costlier and does show the influence of group X = OH and CH(3). Replacing the attacking methyl radical by ethyl makes very little difference to addition at CH(2) and follows the same trend of a higher barrier for addition to the CH(OH) end. In the case of H-addition it is more problematic to draw general conclusions since the DFT-based methodology, CBS-QB3, struggles to locate transition states for some reactions. However, the increase in barrier heights in reaction at the CHX end in comparison to addition at the methylene end is evident. For hydrogen atom reaction with the carbonyl group in the compounds methanal, ethanal, propanal, and butanal we see that for addition at the O-center the barrier heights of ca. 38 kJ mol(-1) are not influenced by the nature of the alkyl group whereas addition at the C-center is different on going from H --> alkyl but seems to be invariant at 20 kJ mol(-1) once alkylated. Rate constants for H-atom elimination from 1-hydroxyethyl, 1-hydroxypropyl, and 1-hydroxybutyl radicals, valid over the range 800-2000 K, are reported. These demonstrate that enols are more prevalent than previously suspected and that 1-buten-1-ol should be almost as abundant as its isomeric aldehyde 1-butanal during the combustion of 1-butanol and that this will also be the case for

  19. Chemical dynamics in time and energy space

    Energy Technology Data Exchange (ETDEWEB)

    Myers, J.D.

    1993-04-01

    The development of a versatile picosecond ultraviolet/vacuum ultraviolet temporal spectrometer and its potential use for measuring internal energy redistribution in isolated molecules are described in detail. A detailed description of the double-pass Nd:YAG amplifier and the dye amplifiers is given with the pulse energies achieved in the visible, ultraviolet, and vacuum ultraviolet. The amplified visible pulses are shown to be of sub-picosecond duration and near transform limited. The instrument`s temporal response ({le}10 ps) is derived from an instrument limited measurement of the dissociation lifetime of methyl iodide at 266 nm. The methyl iodide experiment is used to discuss the various sources of noise and background signals that are intrinsic to this type of experiment. Non-time-resolved experiments measuring the branching ratio and kinetic energy distributions of products from the 193 nm photodissociation of cyclopentadiene and thiophene are presented. These studies were done using the molecular beam Photofragment Translational Spectroscopy (PTS) technique. The results from the cyclopentadiene experiment confirm that H atom elimination to yield the cyclopentadienyl radical is the dominant dissociation channel. A barrier of {ge}5 kcal/mol can be understood in terms of the delocalization of the radical electron of the cyclopentadienyl fragment. A concerted elimination yielding cyclopropene and acetylene was also observed and is proposed to occur via a bicyclo-[2.1.0]pent-2-ene intermediate. Two other channels, yielding acetylene plus the CH{sub 2}CHCH triplet carbene, and CH{sub 2} plus 1-buten-3-yne, are postulated to occur via ring opening. The implications of the experimental results for bulk thermal oxidation and pyrolysis models are discussed. The thiophene experiment shows six competing dissociation channels. The postulated intermediates for the various thiophene dissociation channels include bicyclo, ring opened, and possibly ring contracted forms.

  20. Possible role of laccase from Fusarium incarnatum UC-14 in bioremediation of Bisphenol A using reverse micelles system.

    Science.gov (United States)

    Chhaya, Urvish; Gupte, Akshaya

    2013-06-15

    Bisphenol A [2,2 bis (4 hydroxyphenyl) propane] is widely used in the variety of industrial and residential applications such as the synthesis of polymers including polycarbonates, epoxy resins, phenol resins, polyesters and polyacrylates. BPA has been recognized as an Endocrine Disrupting Chemicals (EDC), thus it is necessary to assess its biodegradability or fate in the natural environment. In general, environmental pollutant such as BPA does not dissolve in aqueous media, owing to their high hydrophobicity, and hence non-aqueous catalysis can be employed to enhance biodegradability of phenolic environmental pollutant. Purified laccase hosted in reverse micelles using ternary system of isooctane: AOT [Bis (2-ethylhexyl) sulphosuccinate sodium salt)]:water having hydration ratio (Wo) of 30 with protein concentration of 43.5 μg/ml was found to eliminate 91.43% of 200 ppm of Bisphenol A at 50 °C, pH-6.0 when incubated with laccase/Reverse Micelles system for 75 min. GC-MS analysis of isooctane soluble fractions detected the presence of 4,4'-(2 hydroxy propane 1,2 diyl) diphenol, bis (4-hydroxylphenyl) butenal and 2-(1-(4-hydroxyphenyl) vinyl) pent-2-enal indicated degradation of BPA by two oxidation steps and one ring opening step (C-C bond cleavage). Laccase/RM system exhibited several advantages for the oxidative degradation of hydrophobic phenols mainly because of the solubility of either enzyme or substrate was improved in organic media and the stable activity of laccase in organic media was achieved. PMID:23611799

  1. Observations and models of emissions of volatile terpenoid compounds from needles of ponderosa pine trees growing in situ: control by light, temperature and stomatal conductance

    Energy Technology Data Exchange (ETDEWEB)

    Harley, Peter; Eller, Allyson; Guenther, Alex; Monson, Russell K.

    2014-07-12

    Terpenoid emissions from ponderosa pine (Pinus ponderosa subsp. scopulorum) were measured in Colorado, USA over two growing seasons to evaluate the role of incident light, needle temperature and stomatal conductance in controlling emissions of 2-methyl-3-buten-2-ol (MBO) and several monoterpenes. MBO was the dominant daylight terpenoid emission, comprising on average 87% of the total flux, and diurnal variations were largely determined by light and temperature. During daytime, oxygenated monoterpenes (especially linalool) comprised up to 75% of the total monoterpenoid flux from needles. A significant fraction of monoterpenoid emissions was light dependent and 13CO2 labeling studies confirmed de novo production. Thus, modeling of monoterpenoid emissions required a hybrid model in which a significant fraction of emissions was dependent on both light and temperature, while the remainder was dependent on temperature alone. Experiments in which stomata were forced to close using abscisic acid demonstrated that MBO and a large fraction of the monoterpene flux, presumably linalool, could be limited at the scale of seconds to minutes by stomatal conductance. Using a previously published model of terpenoid emissions which explicitly accounts for the physico-chemical properties of emitted compounds, we are able to simulate these observed stomatal effects, whether induced through experimentation or arising under naturally fluctuation conditions of temperature and light. This study shows unequivocally that, under naturally occurring field conditions, de novo light dependent monoterpenes can comprise a large fraction of emissions. Differences between the monoterpene composition of ambient air and needle emissions imply a significant non-needle emission source enriched in Δ-3-carene.

  2. Dynamics and mechanisms of hot chemistry stimulated by recoil methods. Progress report, March 1, 1978--February 28, 1979

    International Nuclear Information System (INIS)

    The nuclear recoil chemical activation process in cyclobutane-t and subsequent inter- and intra-molecular energy transfer in recoil tritium and recoil chlorine hot reaction systems are analyzed. A stepladder model for intermolecular energy transfer from cyclobutane-t on collision shows average quanta of energy transferred range from 0.5 to 10 kcal/collision in He, N2, CO2 and cyclobutane bath gases. The recoil energy spectrum of hot chlorine atoms generated via the 37Cl(n,γ)38Cl reaction is also reported. The average recoil energy is found to be 294 eV and the maximum is 528 eV. Average reaction energy is calculated to be relatively independent of composition over the range from 0 to 99% moderation with noble gases in well scavenged systems of moderate reactivity. Geometrical isomerization accompanying the gas phase chlorine atom replacement reaction in 2,3 dichlorohexafluoro-2-butene as a function of moderation has been further investigated. A thermal or near thermal reaction path having a trans/cis product ratio of 1.3 and a high energy process which preferentially forms trans product from both cis and trans reactant are found. Dynamical features associated with the observed high energy inverse isotope effect in the reaction of chlorine atoms with H2 and D2 have been investigated through a non-Boltzmann rate constant analysis. The origin of this kinetic isotope effect is attributed to the secondary reactive process of collisional dissociation of translationally, vibrationally, and rotationally excited hydrogen chloride product molecules. Investigation of the kinetics and mechanisms of photochemical reactions between sulfur dioxide and aliphatic hydrocarbons has been initiated

  3. Key Roles of Lewis Acid-base Pairs on ZnxZryOz in Direct Ethanol/Acetone to Isobutene Conversion

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Junming; Baylon, Rebecca A.; Liu, Changjun; Mei, Donghai; Martin, Kevin J.; Venkitasubramanian, Padmesh; Wang, Yong

    2016-01-20

    The effects of surface acidity on the cascade ethanol-to-isobutene conversion were studied using ZnxZryOz catalysts. The ethanol-to-isobutene reaction was found to be limited by the secondary reaction of the key intermediate, acetone, namely the acetone-to-isobutene reaction. Although the catalysts with coexisting Brønsted acidity could catalyze the rate-limiting acetone-to-isobutene reaction, the presence of Brønsted acidity is also detrimental. First, secondary isobutene isomerization is favored, producing a mixture of butene isomers. Second, undesired polymerization and coke formation prevail, leading to rapid catalyst deactivation. Most importantly, both steady-state and kinetic reaction studies as well as FTIR analysis of adsorbed acetone-d6 and D2O unambiguously showed that a highly active and selective nature of balanced Lewis acid-base pairs was masked by the coexisting Brønsted acidity in the aldolization and self-deoxygenation of acetone to isobutene. As a result, ZnxZryOz catalysts with only Lewis acid-base pairs were discovered, on which nearly a theoretical selectivity to isobutene (~88.9%) was successfully achieved, which has never been reported before. Moreover, the absence of Brønsted acidity in such ZnxZryOz catalysts also eliminates the side isobutene isomerization and undesired polymerization/coke reactions, resulting in the production of high purity isobutene with significantly improved catalyst stability (< 2% activity loss after 200 h time-on-stream). This work not only demonstrates a balanced Lewis acid-base pair for the highly active and selective cascade ethanol-to-isobutene reaction, but also sheds light on the rational design of selective and robust acid-base catalyst for C-C coupling via aldolization reaction.

  4. On-board measurements of gaseous pollutant emission characteristics under real driving conditions from light-duty diesel vehicles in Chinese cities.

    Science.gov (United States)

    Wang, Gang; Cheng, Shuiyuan; Lang, Jianlei; Li, Song; Tian, Liang

    2016-08-01

    A total of 15 light-duty diesel vehicles (LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons (HC) and nitrogen oxides (NOx) at different speeds, chemical species profiles and ozone formation potential (OFP) of volatile organic compounds (VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOx had been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOx emissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%-45.2%, followed by aromatics and alkenes. The most abundant species were propene, ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity (MIR) method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%-91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and 1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene.

  5. Observations and models of emissions of volatile terpenoid compounds from needles of ponderosa pine trees growing in situ: control by light, temperature and stomatal conductance.

    Science.gov (United States)

    Harley, Peter; Eller, Allyson; Guenther, Alex; Monson, Russell K

    2014-09-01

    Terpenoid emissions from ponderosa pine (Pinus ponderosa subsp. scopulorum) were measured in Colorado, USA over two growing seasons to evaluate the role of incident light, needle temperature, and stomatal conductance in controlling emissions of 2-methyl-3-buten-2-ol (MBO) and several monoterpenes. MBO was the dominant daylight terpenoid emission, comprising on average 87% of the total flux, and diurnal variations were largely determined by light and temperature. During daytime, oxygenated monoterpenes (especially linalool) comprised up to 75% of the total monoterpenoid flux from needles. A significant fraction of monoterpenoid emissions was dependent on light and 13CO2 labeling studies confirmed de novo production. Thus, modeling of monoterpenoid emissions required a hybrid model in which a significant fraction of emissions was dependent on both light and temperature, while the remainder was dependent on temperature alone. Experiments in which stomata were forced to close using abscisic acid demonstrated that MBO and a large fraction of the monoterpene flux, presumably linalool, could be limited at the scale of seconds to minutes by stomatal conductance. Using a previously published model of terpenoid emissions, which explicitly accounts for the physicochemical properties of emitted compounds, we were able to simulate these observed stomatal effects, whether induced experimentally or arising under naturally fluctuation conditions of temperature and light. This study shows unequivocally that, under naturally occurring field conditions, de novo light-dependent monoterpenes comprise a significant fraction of emissions in ponderosa pine. Differences between the monoterpene composition of ambient air and needle emissions imply a significant non-needle emission source enriched in Δ-3-carene. PMID:25015120

  6. From Sugars to Wheels: The Conversion of Ethanol to 1,3-Butadiene over Metal-Promoted Magnesia-Silicate Catalysts.

    Science.gov (United States)

    Shylesh, Sankaranarayanapillai; Gokhale, Amit A; Scown, Corinne D; Kim, Daeyoup; Ho, Christopher R; Bell, Alexis T

    2016-06-22

    1,3-Butadiene (1,3-BD) is a high-value chemical intermediate used mainly as a monomer for the production of synthetic rubbers. The ability to source 1,3-BD from biomass is of considerable current interest because it offers the potential to reduce the life-cycle greenhouse gas (GHG) impact associated with 1,3-BD production from petroleum-derived naphtha. Herein, we report the development and investigation of a new catalyst and process for the one-step conversion of ethanol to 1,3-BD. The catalyst is prepared by the incipient impregnation of magnesium oxide onto a silica support followed by the deposition of Au nanoparticles by deposition-precipitation. The resulting Au/MgO-SiO2 catalyst exhibits a high activity and selectivity to 1,3-BD and low selectivities to diethyl ether, ethylene, and butenes. Detailed characterization of the catalyst shows that the desirable activity and selectivity of Au/MgO-SiO2 are a consequence of a critical balance between the acidic-basic sites associated with a magnesium silicate hydrate phase and the redox properties of the Au nanoparticles. A process for the conversion of ethanol to 1,3-BD, which uses our catalyst, is proposed and analyzed to determine the life-cycle GHG impact of the production of this product from biomass-derived ethanol. We show that 1,3-BD produced by our process can reduce GHG emissions by as much as 155 % relative to the conventional petroleum-based production of 1,3-BD. PMID:27198471

  7. Azetidines. 5. Reaction of 1,1,3,3-tetramethyl- and 1-benzyl-1,3,3-trimethylazetidinium ions with butyllithium and phenyllithium. Deuterium labeling as a mechanistic probe

    International Nuclear Information System (INIS)

    The reactions of 1,1,3,3-tetramethylazetidinium iodide (1) and 1-benzyl-1,3,3-trimethylazetidinium bromide (7) with butyllithium and with phenyllithium were studied in ether. The products from the reaction of 1 with butyllithium were 1,3,3-trimethylpyrrolidine (2), 3,3-dimethyl-4-(methylamino)-1-butene (3), 1-(dimethylamino)-2,2-dimethylheptane (4), neopentylpyrrolidine (5), and 1-(dimethylamino)-2,2-dimethylcyclopropane (6). With phenyllithium, 1 gave 2 and 1-(dimethylamino)-2,2-dimethyl-3-phenylpropane (11). With butyllithium, 7 gave 2-phenyl-1,4,4-trimethylpyrrolidine (8), 1-benzyl-3,3-dimethylpyrrilidine (9), and 1-neopentyl-2-phenylpyrrolidine (10). The reaction of phenyllithium with 7 gave only 8 and 9. Mechanistic information was obtained by labeling 1 with deuterium in three different ways: N-methyl-d3,2,2-d2, and N-methyl-d3-2,2-d2. A primary kinetic isotope effect of 9.4 was found for the formation of 2 from 1-N-methyl-d3. When 2 was formed from 1-2,2-d2, a secondary kinetic isotope effect of 1.17 was measured. The formation of 4 from 1-2,2-d2 was accompanied by a primary kinetic isotope effect of 4.7, suggesting a carbene intermediate. Ylide carbanions involving decomposition to a carbene carbanion in the formation of 3 and an azomethine ylide in the formation of 5 and 9 are probable intermediates. It is postulated that the azomethine ylides react with ethylene formed from the reaction of butyllithium with the solvent ether by means of a concerted (4 + 2) cycloaddition reaction. A primary kinetic isotope effect of 20 was found for the formation of pentylbenzene from dibenzyldimethylammonium bromide and butyllithium

  8. Nitric oxide inhibitory substances from Curcuma mangga rhizomes

    Directory of Open Access Journals (Sweden)

    Kanidta Kaewkroek

    2009-08-01

    Full Text Available Curcuma mangga Val. & Zijp. is a member of the Zingiberaceae family commonly grown in Thailand. It is locally known as mango tumeric because of its mango-like smell when the fresh rhizomes are cut. C. mangga is a popular vegetable, the tips of the young rhizomes and shoots are consumed raw with rice. Medicinally, the rhizomes are used as a stomachic and for chest pains, fever, and general debility. It is also used in postpartum care. In the present study, we investigated the anti-inflammatory effect of the extract and compounds from C. mangga rhizomes against lipopolysaccharide (LPS-induced nitric oxide (NO production in RAW 264.7 cell line. From bioassay-guided fractionation, the chloroform fraction exhibited the most potent inhibitory activity with an IC50 value of 2.1 g/ml, followed by the hexane fraction (IC50 = 3.8 g/ml and the ethyl acetate fraction (IC50 = 23.5 g/ml, respectively. Demethoxycurcumin (1 and 3-buten-2-one, 4-[(1R, 4aR, 8aR-decahydro-5, 5, 8a-trimethyl-2-methylene-1-naphthalenyl]-, (3E-rel- (2 were isolated from the chloroform- and hexane fractions, respectively. Bisdemethoxycurcumin (3 whose structure is similar to that of 1 was also tested for NO inhibitory activity. Of the tested compounds, compound 1 exhibited the highest activity with an IC50 value of 12.1 μM, followed by 3(IC50 = 16.9 M and 2 (IC50 = 30.3 M. These results suggest that C. mangga and its compounds exert NO inhibitory activity and have a potential to be developed as a pharmaceutical preparation for treatment of inflammatory-related diseases. Moreover, this is the first report of compound 2 that was isolated from C. mangga rhizomes.

  9. ANALYSIS OF VAPORS FROM METHYLENE CHLORIDE EXTRACTS OF NUCLEAR GRADE HEPA FILTER FIBERGLASS SAMPLES

    Energy Technology Data Exchange (ETDEWEB)

    FRYE JM; ANASTOS HL; GUTIERREZ FC

    2012-06-07

    While several organic compounds were detected in the vapor samples used in the reenactment of the preparation of mounts from the extracts of nuclear grade high-efficiency particulate air filter fiberglass samples, the most significant species present in the samples were methylene chloride, phenol, phenol-d6, and 2-fluorophenol. These species were all known to be present in the extracts, but were expected to have evaporated during the preparation of the mounts, as the mounts appeared to be dry before any vapor was collected. These species were present at the following percentages of their respective occupational exposure limits: methylene chloride, 2%; phenol, 0.4%; and phenol-d6, 0.6%. However, there is no established limit for 2-fluorophenol. Several other compounds were detected at low levels for which, as in the case of 2-fluorophenol, there are no established permissible exposure limits. These compounds include 2-chlorophenol; N-nitroso-1-propanamine; 2-fluoro-1,1{prime}-biphenyl; 1,2-dihydroacenaphthylene; 2,5-cyclohexadiene-1,4-dione,2,6-bis(1,1-dimethylethyl); trimethyl oxirane; n-propylpropanamine; 2-(Propylamino)ethanol; 4-methoxy-1-butene; 6-methyl-5-hepten-2-one; and 3,4-dimethylpyridine. Some of these were among those added as surrogates or spike standards as part ofthe Advanced Technologies and Laboratories International, Inc. preparation ofthe extract of the HEPA filter media and are indicated as such in the data tables in Section 2, Results; other compounds found were not previously known to be present. The main inorganic species detected (sulfate, sodium, and sulfur) are also consistent with species added in the preparation of the methylene chloride extract of the high-efficiency particulate air sample.

  10. Temperature and light dependence of the VOC emissions of Scots pine

    Directory of Open Access Journals (Sweden)

    V. Tarvainen

    2005-01-01

    Full Text Available The volatile organic compound (VOC emission rates of Scots pine (Pinus sylvestris L. were measured from trees growing in a natural forest environment at two locations in Finland. The observed total VOC emission rates varied between 21 and 874 ngg-1 h-1 and 268 and 1670 ngg-1 h-1 in southern and northern Finland, respectively. A clear seasonal cycle was detected with high emission rates in early spring, a decrease of the emissions in late spring and early summer, high emissions again in late summer, and a gradual decrease in autumn. The main emitted compounds were Δ3-carene (southern Finland and α- and β-pinene (northern Finland, with approximate relative contributions of 60–70% and 60–85% of the total observed monoterpene emission rates, respectively. Sesquiterpene (β-caryophyllene and 2-methyl-3-buten-2-ol (MBO emissions were initiated in early summer at both sites. The observed MBO emission rates were between 1 and 3.5% of the total monoterpene emission rates. The sesquiterpene emission rates varied between 2 and 5% of the total monoterpene emission rates in southern Finland, but were high (40% in northern Finland in spring. Most of the measured emission rates were found to be well described by the temperature dependent emission algorithm. The calculated standard emission potentials were high in spring and early summer, decreased somewhat in late summer, and were high again towards autumn. The experimental coefficient β ranged from 0.025 to 0.19 (average 0.10 in southern Finland, with strongest temperature dependence in spring and weakest in late summer. Only the emission rates of 1,8-cineole were found to be both light and temperature dependent.

  11. Emissions and ambient distributions of Biogenic Volatile Organic Compounds (BVOC in a ponderosa pine ecosystem: interpretation of PTR-MS mass spectra

    Directory of Open Access Journals (Sweden)

    S. Kim

    2010-02-01

    Full Text Available Two proton-transfer-reaction mass spectrometry systems were deployed at the Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics and Nitrogen-Southern Rocky Mountain 2008 field campaign (BEACHON-SRM08; July to September, 2008 at the Manitou Forest Observatory in a ponderosa pine woodland near Woodland Park, Colorado USA. The two PTR-MS systems simultaneously measured BVOC emissions and ambient distributions of their oxidation products. Here, we present mass spectral analysis in a wide range of masses (m/z 40+ to 210+ to assess our understanding of BVOC emissions and their photochemical processing inside of the forest canopy. The biogenic terpenoids, 2-methyl-3-butene-2-ol (MBO, 50.2% and several monoterpenes (MT, 33.5% were identified as the dominant BVOC emissions from a transmission corrected mass spectrum (PTR-MS, averaged over the daytime (11 a.m. to 3 p.m., local time of three days. To assess contributions of oxidation products of local BVOC, we calculate an oxidation product spectrum with the OH- and ozone-initiated oxidation product distribution mass spectra of two major BVOC emissions at the ecosystem (MBO and β-pinene that were observed from laboratory oxidation experiments. The majority (~76% of the total signal in the transmission corrected PTR-MS spectra could be explained by identified compounds. The remainder are attributed to oxidation products of BVOC emitted from nearby ecosystems and transported to the site, and oxidation products of unidentified BVOC emitted from the ponderosa pine ecosystem.

  12. Exposure-response of 1,2:3,4-diepoxybutane-specific N-terminal valine adducts in mice and rats after inhalation exposure to 1,3-butadiene.

    Science.gov (United States)

    Georgieva, Nadia I; Boysen, Gunnar; Bordeerat, Narisa; Walker, Vernon E; Swenberg, James A

    2010-06-01

    1,3-Butadiene (BD) is a known rodent and human carcinogen that is metabolized mainly by P450 2E1 to three epoxides, 1,2-epoxy-3-butene (EB), 1,2:3,4-diepoxybutane (DEB), and 1,2-epoxy-3,4-butanediol. The individual epoxides vary up to 200-fold in their mutagenic potency, with DEB being the most mutagenic metabolite. It is important to understand the internal formation of the individual epoxides to assign the relative risk for each metabolite and to understand the molecular mechanisms responsible for extensive species differences in carcinogenicity. This study presents a comprehensive exposure-response for the formation of the DEB-specific N,N-(2,3-dihydroxy-1,4-butadiyl)valine (pyr-Val) in mice and rats. Using nano-ultra high pressure liquid chromatography-tandem-mass spectrometry allowed analysis of pyr-Val in mice and rats exposed to BD as low as 0.1 and 0.5 ppm BD, respectively, and demonstrated significant differences in the amounts and exposure-response of pyr-Val formation. Mice formed 10- to 60-fold more pyr-Val compared to rats at similar exposures. The formation of pyr-Val increased with exposures, and the formation was most efficient with regard to formation per parts per million BD at low exposures. While formation at higher exposures appeared linear in mice, in rats formation saturated at exposures > or = 200 ppm for 10 days. In rats, amounts of pyr-Val were lower after 20 days than after 10 days of exposure, suggesting that the lifespan of rat erythrocytes may be shortened following exposure to BD. This research supports the hypothesis that the lower susceptibility of rats to BD-induced carcinogenesis results from greatly reduced formation of DEB following exposure to BD.

  13. The sedative effect of non-alcoholic beer in healthy female nurses.

    Directory of Open Access Journals (Sweden)

    Lourdes Franco

    Full Text Available INTRODUCTION: The hop (Humulus lupulus L., a component of beer, is a sedative plant whose pharmacological activity is principally due to its bitter resins, in particular to the α-acid degradation product 2-methyl-3-buten-2-ol. The mechanism of action of hop resin consists of raising the levels of the neurotransmitter γ-aminobutyric acid (GABA, an inhibitory neurotransmitter acting in the central nervous system (CNS. OBJECTIVES: To analyze the sedative effect of hops as a component of non-alcoholic beer on the sleep/wake rhythm in a work-stressed population. METHODS: The experiment was conducted with healthy female nurses (n = 17 working rotating and/or night shifts. Overnight sleep and chronobiological parameters were assessed by actigraphy (Actiwatch® after moderate ingestion of non-alcoholic beer containing hops (333 ml with 0.0% alcohol with supper for 14 days (treatment. Data were obtained in comparison with her own control group without consumption of beer during supper. RESULTS: Actigraphy results demonstrated improvement of night sleep quality as regards the most important parameters: Sleep Latency diminished (p≤0.05 in the Treatment group (12.01±1.19 min when compared to the Control group (20.50±4.21 min, as also did Total Activity (p≤0.05; Treatment group = 5284.78±836.99 activity pulses vs Control = 7258.78±898.89 activity pulses. In addition, anxiety as indexed by the State-Trait Anxiety Inventory (STAI decreased in the Treatment group (State Anxiety 18.09±3.8 vs Control 20.69±2.14. CONCLUSION: The moderate consumption of non-alcoholic beer will favour night-time rest, due in particular to its hop components, in addition to its other confirmed benefits for the organism.

  14. A continuous fluorescent assay for the determination of plasma and tissue angiotensin I-converting enzyme activity

    Directory of Open Access Journals (Sweden)

    M.F. Alves

    2005-06-01

    Full Text Available A continuous assay using internally quenched fluorescent peptides with the general sequence Abz-peptidyl-(DnpP-OH (Abz = ortho-aminobenzoic acid; Dnp = 2,4-dinitrophenyl was optimized for the measurement of angiotensin I-converting enzyme (ACE in human plasma and rat tissues. Abz-FRK(DnpP-OH, which was cleaved at the Arg-Lys bond by ACE, was used for the enzyme evaluation in human plasma. Enzymatic activity was monitored by continuous recording of the fluorescence (lambdaex = 320 nm and lambdaem = 420 nm at 37ºC, in 0.1 M Tris-HCl buffer, pH 7.0, with 50 mM NaCl and 10 µM ZnCl2. The assays can be performed directly in the cuvette of the fluorimeter and the hydrolysis followed for 5 to 10 min. ACE measurements in the plasma of 80 healthy patients with Hip-His-Leu and with Abz-FRK(DnpP-OH correlated closely (r = 0.90, P < 0.001. The specificity of the assay was demonstrated by the complete inhibition of hydrolysis by 0.5 µM lisinopril or captopril. Abz-FRK(DnpP-OH cleavage by ACE was monitored in rat lung, kidney, heart, and liver homogenates in the presence of a cocktail of inhibitors containing trans-epoxy-succinyl-L-leucylamido-(4-guanido-butene, pepstatin, phenyl-methylsulfonyl fluoride, N-tosyl-L-phenylalanyl-chloromethyl ketone, and N-tosyl-lysyl-chloromethyl ketone to prevent undesirable hydrolysis. ACE activity in lung, heart and kidney homogenates, but not in liver homogenates, was completely abolished by 0.5 µM lisinopril or captopril. The advantages of the method are the procedural simplicity and the high sensitivity providing a rapid assay for ACE determinations.

  15. Rich premixed laminar methane flames doped by light unsaturated hydrocarbons. II. 1,3-Butadiene

    Energy Technology Data Exchange (ETDEWEB)

    Gueniche, H.A.; Glaude, P.A.; Fournet, R.; Battin-Leclerc, F. [Departement de Chimie-Physique des Reactions, UMR 7630 CNRS, INPL-ENSIC, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France)

    2007-10-15

    In line with the study presented in Part I of this paper, the structure of a rich premixed laminar methane flame doped with 1,3-butadiene has been investigated. The flame contains 20.7% (molar) of methane, 31.4% of oxygen, and 3.3% of 1,3-butadiene, corresponding to an equivalence ratio of 1.8, and a C{sub 4}H{sub 6}/CH{sub 4} ratio of 16%. The flame has been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The temperature ranged from 600 K close to the burner up to 2150 K. Quantified species included the usual methane C{sub 0}-C{sub 2} combustion products and 1,3-butadiene, but also propyne, allene, propene, propane, 1,2-butadiene, butynes, vinylacetylene, diacetylene, 1,3-pentadiene, 2-methyl-1,3-butadiene (isoprene), 1-pentene, 3-methyl-1-butene, benzene, and toluene. To model these new results, some improvements have been made to a mechanism previously developed in our laboratory for the reactions of C{sub 3}-C{sub 4} unsaturated hydrocarbons. The main reaction pathways of consumption of 1,3-butadiene and of formation of C{sub 6} aromatic species have been derived from flow rate analyses. In this case, the C{sub 4} route to benzene formation plays an important role in comparison to the C{sub 3} pathway. (author)

  16. Rich methane premixed laminar flames doped by light unsaturated hydrocarbons. III. Cyclopentene

    Energy Technology Data Exchange (ETDEWEB)

    Gueniche, H.A.; Glaude, P.A.; Fournet, R.; Battin-Leclerc, F. [Departement de Chimie-Physique des Reactions, UMR 7630 CNRS-INPL, Nancy-University, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France)

    2008-01-15

    In line with the studies presented in Parts I (methane flame seeded with allene and propyne) and II (methane flame seeded with 1,3-butadiene) of this paper, the structure of a laminar rich premixed methane flame doped with cyclopentene has been investigated. The gases of this flame contain 15.3% (molar) of methane, 26.7% of oxygen, and 2.4% cyclopentene, corresponding to an overall equivalence ratio of 1.79 and a C{sub 5}H{sub 8}/CH{sub 4} ratio of 15.7%. The flame has been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The measured temperature ranged from 627 K close to the burner up to 2027 K. Species quantified by gas chromatography included the usual methane C{sub 0}-C{sub 2} combustion products, but also propyne, allene, propene, propane, 1-butene, 1,3-butadiene, 1,2-butadiene, vinylacetylene, diacetylene, cyclopentadiene, 1,3-pentadiene, benzene, and toluene. A new mechanism for the oxidation of cyclopentene has been developed and added to the former model for the oxidation of small unsaturated hydrocarbons, benzene, and toluene described in Parts I and II. The whole mechanism involved 175 species in 1134 reactions. The main reaction pathways of consumption of cyclopentene and of formation of benzene and toluene are presented and discussed from flow rate analyses. (author)

  17. Rich methane premixed laminar flames doped with light unsaturated hydrocarbons

    Energy Technology Data Exchange (ETDEWEB)

    Gueniche, H.A.; Glaude, P.A.; Dayma, G.; Fournet, R.; Battin-Leclerc, F. [Departement de Chimie-Physique des Reactions, Nancy University, CNRS, ENSIC, 1 rue Grandville, BP 20451, 54001 Nancy Cedex (France)

    2006-09-15

    The structure of three laminar premixed rich flames has been investigated: a pure methane flame and two methane flames doped by allene and propyne, respectively. The gases of the three flames contain 20.9% (molar) of methane and 33.4% of oxygen, corresponding to an equivalence ratio of 1.25 for the pure methane flame. In both doped flames, 2.49% of C{sub 3}H{sub 4} was added, corresponding to a ratio C{sub 3}H{sub 4}/CH{sub 4} of 12% and an equivalence ratio of 1.55. The three flames have been stabilized on a burner at a pressure of 6.7 kPa using argon as dilutant, with a gas velocity at the burner of 36 cm/s at 333 K. The concentration profiles of stable species were measured by gas chromatography after sampling with a quartz microprobe. Quantified species included carbon monoxide and dioxide, methane, oxygen, hydrogen, ethane, ethylene, acetylene, propyne, allene, propene, propane, 1,2-butadiene, 1,3-butadiene, 1-butene, isobutene, 1-butyne, vinylacetylene, and benzene. The temperature was measured using a PtRh (6%)-PtRh (30%) thermocouple settled inside the enclosure and ranged from 700 K close to the burner up to 1850 K. In order to model these new results, some improvements have been made to a mechanism previously developed in our laboratory for the reactions of C{sub 3}-C{sub 4} unsaturated hydrocarbons. The main reaction pathways of consumption of allene and propyne and of formation of C{sub 6} aromatic species have been derived from flow rate analyses. (author)

  18. Flame Propagation of Butanol Isomers/Air Mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Veloo, Peter S.; Egolfopoulos, Fokion N.

    2011-01-01

    An experimental and computational study was conducted on the propagation of flames of saturated butanol isomers. The experiments were performed in the counterflow configuration under atmospheric pressure, unburned mixture temperature of 343 K, and for a wide range of equivalence ratios. The experiments were simulated using a recent kinetic model for the four isomers of butanol. Results indicate that n-butanol/air flames propagate somewhat faster than both sec-butanol/air and iso-butanol/air flames, and that tert-butanol/air flames propagate notably slower compared to the other three isomers. Reaction path analysis of tert-butanol/air flames revealed that iso-butene is a major intermediate, which subsequently reacts to form the resonantly stable iso-butenyl radical retarding thus the overall reactivity of tert-butanol/air flames relatively to the other three isomers. Through sensitivity analysis, it was determined that the mass burning rates of sec-butanol/air and iso-butanol/air flames are sensitive largely to hydrogen, carbon monoxide, and C{sub 1}–C{sub 2} hydrocarbon kinetics and not to fuel-specific reactions similarly to n-butanol/air flames. However, for tert-butanol/air flames notable sensitivity to fuel-specific reactions exists. While the numerical results predicted closely the experimental data for n-butanol/air and sec-butanol/air flames, they overpredicted and underpredicted the laminar flame speeds for iso-butanol/air and tert-butanol/air flames respectively. It was demonstrated further that the underprediction of the laminar flame speeds of tert-butanol/air flames by the model was most likely due to deficiencies of the C{sub 4}-alkene kinetics.

  19. The progress of SINOPEC methanol-to-olefins (S-MTO) technology

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Hongxing; Xie, Zaiku; Zhao, Guoliang [SINOPEC Shanghai Research Institute of Petrochemical Technology (China)

    2013-11-01

    It is widely recognized that naphtha steam crackers and FCC units are the main current sources of ethylene and propylene. On the condition of high oil price, olefin producers are striving to develop new economical routes to produce ethylene and propylene with low-cost feedstocks. Methanol to olefins (MTO) has aroused great attention in recent years, and SINOPEC has developed a new kind of MTO process named S-MTO which features high olefins selectivity, high methanol conversion and low catalyst consumption. Puyang Zhongyuan 200 KTA S-MTO has been in steady operation for more than 17 months. The catalyst used in the process is based on a silicoaluminophosphate, SAPO-34, which has very high carbon selectivity to low carbon olefins. Results from the commercial plant show that S-MTO process converts methanol to ethylene and propylene at about 81% carbon selectivity. The carbon selectivity approaches 92% if butenes are also accounted for as part of the product. Typically, the ratio of propylene to ethylene can range from 0.6 to 1.3. When combined with OCC (Olefin Catalytic Cracking) process to convert the heavier olefins, the overall yield of ethylene and propylene can increase to 85% {proportional_to} 87% and propylene-ethylene ratios of more than 1.5 are achievable. Other co-products include very small amounts of C1-C4 paraffins, hydrogen, CO and CO{sub 2}, as well as heavier oxygenates only with ppm level. Because of the quick deactivation of MTO catalyst, a kind of high efficiency fast fluidized bed reactor is adopted. The activity of deactivated catalyst is recovered by burning the coke in the regenerator. This paper gives an updated introduction of S-MTO technology developed by SINOPEC SRIPT. (orig.)

  20. Production and use of light olefins. Preprints of the conference

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Buzzoni, R.; Leitner, W.; Lercher, J.A.; Lichtscheidl, J.; Nees, F.; Santacesaria, E. (eds.)

    2009-07-01

    Within the conference of the German Society for Petroleum and Coal Science and Technology e.V. (Hamburg, Federal Republic of Germany) in Berlin (Federal Republic of Germany) at 28th to 30th September, 2009, the following lectures were held: (1) Steamcracking - State of the Art (H. Zimmermann); (2) Diversify Feedstock Options to Olefin Production (Q. Ling et al.); (3) Syngas to lower olefins (E. Schwab et al.); (4) STAR process registered for the on-purpose production of propylene (K. Bueker); (5) The catalytic activity of zinc oxide supported on aerosil for C-H activation of light alkanes (S. Arndt et al.); (6) Novel catalytic approaches for the oxidative dehydrogenation of ethane (D. Hartmann); (7) A comparison of the active sites structures of homogeneous and heterogeneous olefin polymerisation catalysts (A. Zecchina); (8) Catalytic strategies in metathesis (C. Coperet); (9) Multi-technology integrated production and consumption of olefins (J. Popp et al.); (10) Olefin oligomerization for the production of fuels and petrochemicals (H. Olivier-Bourbigou et al.); (11) Dieselization of the world - How to increase diesel yield in a refinery (A. Dueker); (12) Isomerization of butenes: LyondellBasell's Isomplus technology development (T. Zak et al.); (13) Valuable products from butadiene, carbon dioxide and further base chemicals (A. Behr); (14) The partial oxidation of propene to propylene oxide using N{sub 2}O as an oxidant (T. Thoemmes); (15) Alternative feedstocks for olefin production: What role will ethanol play? (B.R. Maughon); (16) Production of light olefins from renewable resources - The effect of deoxygenation degree on yields of light olefins (D. Kubicka et al.); (17) Recovery of low olefins from refinery offgases (M. Bender).

  1. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    P. O. Wennberg

    2010-04-01

    Full Text Available Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene, the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA via methacrolein (a C4-unsaturated aldehyde under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232 is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(OOONO2 formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios, the SOA yields from isoprene high-NOxphotooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  2. Role of aldehyde chemistry and NOx concentrations in secondary organic aerosol formation

    Directory of Open Access Journals (Sweden)

    P. O. Wennberg

    2010-08-01

    Full Text Available Aldehydes are an important class of products from atmospheric oxidation of hydrocarbons. Isoprene (2-methyl-1,3-butadiene, the most abundantly emitted atmospheric non-methane hydrocarbon, produces a significant amount of secondary organic aerosol (SOA via methacrolein (a C4-unsaturated aldehyde under urban high-NOx conditions. Previously, we have identified peroxy methacryloyl nitrate (MPAN as the important intermediate to isoprene and methacrolein SOA in this NOx regime. Here we show that as a result of this chemistry, NO2 enhances SOA formation from methacrolein and two other α, β-unsaturated aldehydes, specifically acrolein and crotonaldehyde, a NOx effect on SOA formation previously unrecognized. Oligoesters of dihydroxycarboxylic acids and hydroxynitrooxycarboxylic acids are observed to increase with increasing NO2/NO ratio, and previous characterizations are confirmed by both online and offline high-resolution mass spectrometry techniques. Molecular structure also determines the amount of SOA formation, as the SOA mass yields are the highest for aldehydes that are α, β-unsaturated and contain an additional methyl group on the α-carbon. Aerosol formation from 2-methyl-3-buten-2-ol (MBO232 is insignificant, even under high-NO2 conditions, as PAN (peroxy acyl nitrate, RC(OOONO2 formation is structurally unfavorable. At atmospherically relevant NO2/NO ratios (3–8, the SOA yields from isoprene high-NOx photooxidation are 3 times greater than previously measured at lower NO2/NO ratios. At sufficiently high NO2 concentrations, in systems of α, β-unsaturated aldehydes, SOA formation from subsequent oxidation of products from acyl peroxyl radicals+NO2 can exceed that from RO2+HO2 reactions under the same inorganic seed conditions, making RO2+NO2 an important channel for SOA formation.

  3. Characterization and Dynamics of Substituted Ruthenacyclobutanes Relevant to the Olefin Cross-Metathesis Reaction

    Science.gov (United States)

    Blake, Garrett; VanderVelde, David G.; Grubbs, Robert H.

    2011-01-01

    The reaction of the phosphonium alkylidene [(H2IMes)RuCl2=CHP(Cy)3)]+ BF4– with propene, 1-butene, and 1-hexene at –45 °C affords various substituted, metathesis-active ruthenacycles. These metallacycles were found to equilibrate over extended reaction times in response to decreases in ethylene concentrations, which favored increased populations of α-monosubstituted and α,α’-disubstituted (both cis and trans) ruthenacycles. On an NMR timescale, rapid chemical exchange was found to preferentially occur between the β-hydrogens of the cis and trans stereoisomers prior to olefin exchange. Exchange on an NMR timescale was also observed between the α- and β-methylene groups of the monosubstituted ruthenacycle (H2IMes)Cl2Ru(CHRCH2CH2) (R = CH3, CH2CH3, (CH2)3CH3). EXSY NMR experiments at –87 °C were used to determine the activation energies for both of these exchange processes. In addition, new methods have been developed for the direct preparation of metathesis-active ruthenacyclobutanes via the protonolysis of dichloro(1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene)(benzylidene) bis(pyridine)ruthenium(II) and its 3-bromopyridine analog. Using either trifluoroacetic acid or silica-bound toluenesulfonic acid as the proton source, the ethylene-derived ruthenacyclobutane (H2IMes)Cl2Ru(CH2CH2CH2) was observed in up to 98% yield via NMR at –40 °C. On the basis of these studies, mechanisms accounting for the positional and stereochemical exchange within ruthenacyclobutanes are proposed, as well as the implications of these dynamics towards olefin metathesis catalyst and reaction design are described. PMID:21452876

  4. Species difference in metabolism of inhaled butadiene

    International Nuclear Information System (INIS)

    Chronic exposure of B6C3F1 mice and Sprague-Dawley rats to butadiene (BD) produced a very high incidence of cancer in mice while the incidence in rats was much lower with different tissues affected. Studies at this institute indicate that for equivalent exposures, the blood BD epoxide concentrations in mice are 5-fold higher than in rats and > 10-fold higher than in Cynomolgus monkeys. In this study, the profiles of urinary metabolites of butadiene were determined in Cynomolgus monkeys, F344/N rats, Sprague Dawley rats, B6C3F1 mice and Syrian hamsters, species containing widely divergent hepatic epoxide hydrolase (EH) activities. Animals were exposed for 2 hr to 8,000 ppm [14C]BD and 24-hr urine samples were analyzed for metabolites. Two major urinary metabolites were identified, N-acetyl-S-(-1(or 2)-3-butene-2(or 1)-ol)cysteine (1) and N-acetyl-S-(-4-butane-1,2-diol)cysteine (2). Monkeys exposed by inhalation produced primarily metabolite 2, while rodent species produced 1-4 times as much of 1 compared to 2. The ratio of 2/1 formation was related to the hepatic epoxide hydrolase activity in different species. The high 2/1 ratio in monkeys was consistent with the lower blood epoxide levels in this species. If BD metabolism by humans is similar to that in the monkey, exposure of humans to BD may result in lower tissue concentrations of reactive metabolites than an equivalent exposure of rodents. This has important implications for assessing the risk to humans of BD exposure based on rodent studies

  5. Comparative Study of Cl-Atom Reactions in Solution Using Time-Resolved Vibrational Spectroscopy.

    Science.gov (United States)

    Shin, Jae Yoon; Case, Amanda S; Crim, F Fleming

    2016-04-28

    A Cl atom can react with 2,3-dimethylbutane (DMB), 2,3-dimethyl-2-butene (DMBE), and 2,5-dimethyl-2,4-hexadiene (DMHD) in solution via a hydrogen-abstraction reaction. The large exoergicity of the reaction between a Cl atom and alkenes (DMBE and DMHD) makes vibrational excitation of the HCl product possible, and we observe the formation of vibrationally excited HCl (v = 1) for both reactions. In CCl4, the branching fractions of HCl (v = 1), Γ (v = 1), for the Cl-atom reactions with DMBE and DMHD are 0.14 and 0.23, respectively, reflecting an increased amount of vibrational excitation in the products of the more exoergic reaction. In addition, Γ (v = 1) for both reactions is larger in the solvent CDCl3, being 0.23 and 0.40, as the less viscous solvent apparently dampens the vibrational excitation of the nascent HCl less effectively. The bimolecular reaction rates for the Cl reactions with DMB, DMBE, and DMHD in CCl4 are diffusion limited (having rate constants of 1.5 × 10(10), 3.6 × 10(10), and 17.5 × 10(10) M(-1) s(-1), respectively). In fact, the bimolecular reaction rate for Cl + DMHD exceeds a typical diffusion-limited reaction rate, implying that the attractive intermolecular forces between a Cl atom and a C═C bond increase the rate of favorable encounters. The 2-fold increase in the reaction rate of the Cl + DMBE reaction from that of the Cl + DMB reaction likely reflects the effect of the C═C bond, while both the number of C═C bonds and the molecular geometry likely play a role in the large reaction rate of the Cl + DMHD reaction.

  6. Ti-MSU分子筛催化1-丁烯氧化制环氧丁烷的研究%Research on Epoxybutane from 1-Butylene by Ti-MSU Molecular Sieve Catalytic Oxidation

    Institute of Scientific and Technical Information of China (English)

    吴美玲; 周灵杰; 陈玮娜

    2014-01-01

    通过液相浸渍法制备Ti 质量分数为5�5%的Ti-MSU分子筛催化剂,并采用X射线衍射、N2吸附-脱附对催化剂样品进行表征。考察了Ti-MSU催化剂对以过氧化氢异丙苯( CHP)、1-丁烯为原料制备环氧丁烷的反应工艺条件的影响。结果表明,当催化剂床层温度为100℃、反应压力为3�0 MPa、1-丁烯/CHP摩尔比为10∶1、CHP空速为2 h-1时,CHP的转化率达到81�2%,1,2-环氧丁烷( BO)选择性为60�2%,苄醇( DMBA)选择性为87�2%。%5.5%Ti-MSU molecular sieve catalyst was prepared by liquid phase impregnation method. The sam-ple was characterized by X-ray diffraction and N2 adsorption-desorption. With cumene hydroperoxide ( CHP) ,1-bu-tene as raw material,the influence of the process conditions of 5.5%Ti-MSU catalyst on epoxybutane had been in-vestigated. The conversion of CHP was 81.2%,1,2-epoxybutane ( BO) selectivity was 60.2%, benzyl alcohol ( DMBA) selectivity was 87.2%, when the optimum reaction conditions was 100℃ catalyst bed,3.0 MPa reactivity pressure,10∶1 1-butylene/CHP molar ratio and 2h-1 space velocity of CHP.

  7. Characterization of gas station emissions during the CAREBeijing 2008 field study

    Directory of Open Access Journals (Sweden)

    J. Zheng

    2011-05-01

    Full Text Available A proton transfer-reaction mass spectrometer (PTR-MS onboard a mobile laboratory was used to conduct emission measurements at eight gas stations in Beijing during the CAREBeijing 2008 campaign. Benzene, toluene, C8-, C9-aromatics, methanol, MTBE, butenes and pentenes were the major volatile organic compounds (VOCs detected during the measurements. An inter-comparison between the PTR-MS and an on-line GC/MS/FID system was also conducted and the result showed good agreement between the two instruments (Interception < 0.08 ppbv, 0.72 < Slope < 0.95, and R2 > 0.92. A Gaussian point source plume model was applied to evaluate the VOCs emission rates. The results showed that on average about 4.5 mt of gasoline were emitted from gas stations in Beijing per day. The estimated emission factor (EF for gas stations due to refueling processes was about 0.5 kg t−1, which was significantly lower than a value of 2.49 kg t−1 obtained in 2002, indicating a successful implementation of vapor recovery system in the gas stations of Beijing. On average, about 18 ppbv of benzene has been detected at one gas station, twice as much as the US Environmental Protection Agency (EPA recommended safe chronic exposure level and implying a potential public health concern. MTBE and aromatics were found to be the major antiknocking additives used in gasoline supplied in Beijing. Our results reveal that emissions from gas stations represent an important source for VOCs in megacity Beijing and need to be properly included in emission inventories to assess their roles in photochemical ozone production and secondary organic aerosol formation. Furthermore, promoting methanol-blended fuel in Beijing can be an effective way to reduce toxic air pollutants emission.

  8. Synergy among phytochemicals within crucifers: does it translate into chemoprotection?

    Science.gov (United States)

    Wallig, Matthew A; Heinz-Taheny, Kathleen M; Epps, Donna L; Gossman, Tamara

    2005-12-01

    The association between cruciferous vegetables and cancer prevention has been linked to glucosinolate derivatives. These phytochemicals enhance endogenous detoxification, leading to inactivation of potential carcinogens before initiation occurs. Two derivatives, indole-3-carbinol (I3C) and 1-cyano-2-hydroxy-3-butene (crambene) were shown in rats to induce a synergistic enhancement of detoxification enzyme activity. To follow up on these findings, a short-term carcinogenicity study using aflatoxin B1 (AFB(1)) was performed in which male F344 rats were fed diets supplemented with these 2 compounds alone or in combination. Groups included a negative control group (no AFB(1), crambene, or I3C), a crambene group (diet 0.150% crambene), an I3C group (diet 0.165% I3C), a high-dose group (diet 0.150% crambene, 0.165% I3C) a low-dose group (diet 0.030% crambene, 0.033% I3C), and a positive control group (AFB(1) treatment only). AFB(1) was administered after 2 wk of dietary pretreatment. Liver sections were scored for lesions including karyomegaly, apoptosis, and biliary hyperplasia and evaluated for expression of the preneoplastic marker glutathione S-transferase-pi (GSTP). I3C and crambene groups were protected against AFB(1) toxicity whereas the low-dose group was not. The high-dose group had scores close to those of the negative controls. For log(10) transformed 2- and 3-dimensional GSTP data, the high-dose group demonstrated synergistic reduction in GSTP-positive area and an additive reduction in GSTP-positive volume compared with the crambene and I3C groups. The low-dose group had no effect. In conclusion, high combination dietary doses of I3C and crambene demonstrated enhanced protection from AFB(1). Low combination doses, as might be realistically in the diet, were not effective.

  9. Amylenes Do Not Lead to Bacterial Mutagenicity in Contrast to Structurally Related Epoxides

    Directory of Open Access Journals (Sweden)

    Götz A. Westphal

    2014-01-01

    Full Text Available Amylenes are unsaturated hydrocarbons (C5H10, such as 1-pentene, 2-pentene, 2-methyl-but-1-en (3-methyl-1-butene, 2-methyl-but-2-en (isopentene, and 3-methyl-but-1-en. We investigated bacterial mutagenicity of 1-pentene, 2-pentene, and 3-methyl-but-1-en in the Ames test. 2-Pentene was investigated as racemate and as pure diastereomers. We included the methyltransferase deficient Salmonella Typhimurium strain YG7108 and the application of a gas-tight preincubation to reduce the risk of false negative results. 1,2-Epoxypentane which may arise from 1-pentene was used as positive control. None of the investigated amylenes showed mutagenic effects, whereas 1,2-epoxypentane was mutagenic exceeding 100 μg per plate. An exceptional high reverse mutation in the negative control plates in the experiments with 1,2-epoxypentane was obviously caused by evaporation into the incubator which was shown by placing the control plates in a separate apparatus. No differences were seen upon use of YG7108 and its parent strain TA1535. In conclusion, 1,2-epoxypentane is most probably not a substrate of the deleted bacterial methyltransferases. The comparison of the bacterial mutagenicity of the investigated amylenes and 1,2-epoxipentane suggests that epoxidation of amylenes in the S9-mix does not proceed effectively or is counterbalanced by detoxifying reactions. The assessment of mutagenic effects of short chained aliphatic epoxides can be underestimated due to the evaporation of these compounds.

  10. Sources of Volatile Organic Compounds (VOCs) in the UAE

    Science.gov (United States)

    Abbasi, Naveed; Majeed, Tariq; Iqbal, Mazhar; Riemer, Daniel; Apel, Eric; Lootah, Nadia

    The gas chromatography-flame ionization detection/mass spectrometry system has been used to identify major volatile organic compounds (VOCs) sources in the UAE (latitude 24.45N; longitude 54.22E). VOCs are emitted from an extensive number of sources in urban environments including fuel production, distribution, and consumption. Transport sources contribute a substantial portion of the VOC burden to the urban atmosphere in developed regions. UAE is located at the edge of the Persian Gulf and is highly affected by emissions from petrochemical industries in neighbouring Saudi Arabia, Qatar, and Iran. VOCs emerging from these industries can be transported to the UAE with jet streams. The analysis of the collected air samples at three locations in Sharjah, UAE during the autumn and winter seasons indicates the presence of more than 100 VOC species. The concentrations of these species vary in magnitudes but the most prominent are: acetylene, ethane, propane, butane, pentane, benzene, and toluene. The possible tracers for various emission sources have also been identified such as 2-methylpentane, 1, 3-butadiene and 2, 2-dimethlybutane for vehicle exhaust, the light hydrocarbons, namely n-butane, trans-2-butene, and n-pentane for gasoline vapor, and n-nonane, n-decane, and n-undecane for diesel vapor and asphalt application processes. As various emission sources are characterized by overlapping VOC species, the ratio of possible VOC tracers are used to quantify the contribution of different sources. Our aim in this paper is to explore and discuss possible impacts of transported emissions on the local VOC emission inventory from various sources for the UAE. This work is partially supported by Office of Development and Alumni Affairs at the American University of Sharjah, U.A.E.

  11. A metabolomics strategy to explore urinary biomarkers and metabolic pathways for assessment of interaction between Danhong injection and low-dose aspirin during their synergistic treatment.

    Science.gov (United States)

    Li, Jianping; Guo, Jianming; Shang, Erxin; Zhu, Zhenhua; Zhu, Kevin Yue; Li, Shujiao; Zhao, Buchang; Jia, Lifu; Zhao, Jing; Tang, Zhishu; Duan, Jinao

    2016-07-15

    The drug combination of Danhong injection (DHI) and low-dose aspirin (ASA) was frequently applied for the treatment of cardiovascular and cerebrovascular diseases. Due to the drug interactions, a lot of potential benefits and risks might exist side by side in the course of combination therapy. However, there had been no studies of interaction between DHI and ASA. Metabolomics was a powerful tool to explore endogenous biomarkers and metabolic pathways. In present study, metabolic profiling with ultra-high-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF/MS) coupled with multivariate statistical analysis was performed to provide insight into understanding the interaction between DHI and low-dose ASA. Eleven potential biomarkers of three types were identified and seven metabolic pathways were constructed. The results showed that the interaction between DHI and low-dose ASA during synergistic treatment indeed affected some key endogenous biomarkers and metabolic pathways, which could not happen when DHI or low-dose ASA was used alone. The quality and quantity of endogenous metabolite were both influenced by interaction between DHI and low-dose ASA. In details, the amount of flavin mononucleotide, L-2, 4-diaminobutyric acid (DABA) and 4-aminohippuric acid were significantly increased. On the contrary, the amount of 3-methyluridine, 4, 6-dihydroxyquinoline, cortolone-3-glucuronide, and serotonin were significantly decreased. Furthermore, O-phosphotyrosine, 3-methyl-2-butenal, indoxyl sulfate and dolichyl diphosphate were disappeared in urine. As to metabolic pathways, riboflavin metabolism, pentose and glucuronate interconversions, and tryptophan metabolism were all significantly influenced. The emerging alterations of biomarkers and metabolic pathways were associated with a lot of drugs and diseases based on literature researches, which might influence the co-administration of other drugs or the treatments of relevant

  12. Preparação e Avaliação Térmica e Reológica de Misturas de PEBD/PELBD Preparation of LDPE/LLDPE Blends and Thin Rheological and Calorimetric Evaluation

    Directory of Open Access Journals (Sweden)

    Márcia R. Becker

    2002-01-01

    Full Text Available Misturas de Polietileno de Baixa Densidade (PEBD com diferentes tipos e proporções de Polietilenos Lineares de Baixa Densidade (PELBD foram preparadas em extrusora de rosca simples e dupla a fim de verificar a influência destes últimos na viscosidade e cristalinidade das misturas. As misturas de PEBD com PELBD foram avaliadas através de reometria capilar e calorimetria (DSC. As misturas de PEBD com PELBD com comonômero de 1-buteno e de 1-octeno, preparadas em extrusora de rosca simples ou dupla, não apresentaram diferenças no perfil das curvas reológicas. Entretanto, as misturas de PEBD com PELBD com comonômero 1-hexeno apresentaram diferenças nas curvas de viscosidade. Verificou-se que a adição de PELBD na mistura modifica significativamente a viscosidade principalmente em altas taxas de cisalhamento. Pela avaliação das curvas de fusão, observou-se que o aumento da concentração de PELBD nas misturas provoca uma variação no comportamento térmico das mesmas com o conseqüente alargamento da faixa de fusão.LDPE and LLDPE blends were prepared in a single and twin screw mixer, using different kinds and proportions of the LLDPE in order to evaluate their influence on the viscosity and cristallinity of the blends. The blends with LLDPE made with butene or hexene or octene comonomer, prepared in a twin or single screw mixer, did not show significant differences in their curves of viscosity versus shear rate. The addition of LLDPE in the PEBD changes the viscosimetric behavior of the blends especially at higher shear rate. With Differential Scanning Calorimetry we observed that the incorporation of LLDPE in the blends changes the behavior of melting curves due to its different types of crystallites.

  13. High throughput HPLC-ESI(-)-MS/MS methodology for mercapturic acid metabolites of 1,3-butadiene: Biomarkers of exposure and bioactivation.

    Science.gov (United States)

    Kotapati, Srikanth; Esades, Amanda; Matter, Brock; Le, Chap; Tretyakova, Natalia

    2015-11-01

    1,3-Butadiene (BD) is an important industrial and environmental carcinogen present in cigarette smoke, automobile exhaust, and urban air. The major urinary metabolites of BD in humans are 2-(N-acetyl-L-cystein-S-yl)-1-hydroxybut-3-ene/1-(N-acetyl-L-cystein-S-yl)-2-hydroxybut-3-ene (MHBMA), 4-(N-acetyl-L-cystein-S-yl)-1,2-dihydroxybutane (DHBMA), and 4-(N-acetyl-L-cystein-S-yl)-1,2,3-trihydroxybutyl mercapturic acid (THBMA), which are formed from the electrophilic metabolites of BD, 3,4-epoxy-1-butene (EB), hydroxymethyl vinyl ketone (HMVK), and 3,4-epoxy-1,2-diol (EBD), respectively. In the present work, a sensitive high-throughput HPLC-ESI(-)-MS/MS method was developed for simultaneous quantification of MHBMA and DHBMA in small volumes of human urine (200 μl). The method employs a 96 well Oasis HLB SPE enrichment step, followed by isotope dilution HPLC-ESI(-)-MS/MS analysis on a triple quadrupole mass spectrometer. The validated method was used to quantify MHBMA and DHBMA in urine of workers from a BD monomer and styrene-butadiene rubber production facility (40 controls and 32 occupationally exposed to BD). Urinary THBMA concentrations were also determined in the same samples. The concentrations of all three BD-mercapturic acids and the metabolic ratio (MHBMA/(MHBMA+DHBMA+THBMA)) were significantly higher in the occupationally exposed group as compared to controls and correlated with BD exposure, with each other, and with BD-hemoglobin biomarkers. This improved high throughput methodology for MHBMA and DHBMA will be useful for future epidemiological studies in smokers and occupationally exposed workers. PMID:25727266

  14. SmoXYB1C1Z of Mycobacterium sp. strain NBB4: a soluble methane monooxygenase (sMMO)-like enzyme, active on C2 to C4 alkanes and alkenes.

    Science.gov (United States)

    Martin, Kiri E; Ozsvar, Jazmin; Coleman, Nicholas V

    2014-09-01

    Monooxygenase (MO) enzymes initiate the aerobic oxidation of alkanes and alkenes in bacteria. A cluster of MO genes (smoXYB1C1Z) of thus-far-unknown function was found previously in the genomes of two Mycobacterium strains (NBB3 and NBB4) which grow on hydrocarbons. The predicted Smo enzymes have only moderate amino acid identity (30 to 60%) to their closest homologs, the soluble methane and butane MOs (sMMO and sBMO), and the smo gene cluster has a different organization from those of sMMO and sBMO. The smoXYB1C1Z genes of NBB4 were cloned into pMycoFos to make pSmo, which was transformed into Mycobacterium smegmatis mc(2)-155. Cells of mc(2)-155(pSmo) metabolized C2 to C4 alkanes, alkenes, and chlorinated hydrocarbons. The activities of mc(2)-155(pSmo) cells were 0.94, 0.57, 0.12, and 0.04 nmol/min/mg of protein with ethene, ethane, propane, and butane as substrates, respectively. The mc(2)-155(pSmo) cells made epoxides from ethene, propene, and 1-butene, confirming that Smo was an oxygenase. Epoxides were not produced from larger alkenes (1-octene and styrene). Vinyl chloride and 1,2-dichloroethane were biodegraded by cells expressing Smo, with production of inorganic chloride. This study shows that Smo is a functional oxygenase which is active against small hydrocarbons. M. smegmatis mc(2)-155(pSmo) provides a new model for studying sMMO-like monooxygenases. PMID:25015887

  15. Unité micropilote pour l'étude de charges de vapocraquage. Exemple d'un mélange de normales paraffines Micropilot Plant for the Study of Steam-Cracking Feedstocks. Example of a Mixture of Normal Paraffins

    Directory of Open Access Journals (Sweden)

    Billaud F.

    2006-11-01

    Full Text Available La décomposition thermique d'un mélange de normales paraffines (nom commercial Solpar , provenance British Petroleum a été étudiée dans une unité micropilote entre 640 et 820 °C ; les produits principaux dosés par chromatographie en phase gazeuse sont : hydrogène, méthane, éthylène, propène, butène-1, pentène-1, hexène-1, heptène-1, octène-1 et nonène-1. Un des intérêts du travail est la description mécanistique de la pyrolyse d'un hydrocarbure lourd qui permet d'interpréter la formation primaire de ces produits principaux. On a aussi montré expérimentalement l'intérêt du vapocraquage haute température et faible temps de séjour lorsque l'on veut produire sélectivement des oléfines légères en minimisant la production d'aromatiques. The thermal decomposition of a mixture of normal paraffins (trademark Solpar, by British Petroleum has been studied in a micropilot plant in a temperature range of 640 to 820°C. The main products determined by gas chromatography are hydrogen, methane, ethylene, propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene and 1-nonene. On of the important results of the present work is the mechanistic description of heavy hydrocarbon pyrolysis so that the primary formation of these principal products can be interpreted. Moreover, the advantage of using high-temperature steam cracking and short residence time for the selective production of light olefins, thus minimizing production of aromatics, is experimentally demonstrated.

  16. Polyphenol extract from Phellinus igniarius protects against acrolein toxicity in vitro and provides protection in a mouse stroke model.

    Directory of Open Access Journals (Sweden)

    Papawee Suabjakyong

    Full Text Available The basidiomycetous mushroom Phellinus igniarius (L. Quel. has been used as traditional medicine in various Asian countries for many years. Although many reports exist on its anti-oxidative and anti-inflammatory activities and therapeutic effects against various diseases, our current knowledge of its effect on stroke is very limited. Stroke is a neurodegenerative disorder in which oxidative stress is a key hallmark. Following the 2005 discovery by Igarashi's group that acrolein produced from polyamines in vivo is a major cause of cell damage by oxidative stress, we now describe the effects of anti-oxidative extracts from P. igniarius on symptoms of experimentally induced stroke in mice. The toxicity of acrolein was compared with that of hydrogen peroxide in a mouse mammary carcinoma cell line (FM3A. We found that the complete inhibition of FM3A cell growth by 5 μM acrolein could be prevented by crude ethanol extract of P. igniarius at 0.5 μg/ml. Seven polyphenol compounds named 3,4-dihydroxybenzaldehyde, 4-(3,4-dihydroxyphenyl-3-buten-2one, inonoblin C, phelligridin D, inoscavin C, phelligridin C and interfungin B were identified from this ethanolic extract by LCMS and 1H NMR. Polyphenol-containing extracts of P. igniarius were then used to prevent acrolein toxicity in a mouse neuroblastoma (Neuro-2a cell line. The results suggested that Neuro-2a cells were protected from acrolein toxicity at 2 and 5 μM by this polyphenol extract at 0.5 and 2 μg/ml, respectively. Furthermore, in mice with experimentally induced stroke, intraperitoneal treatment with P. igniarius polyphenol extract at 20 μg/kg caused a reduction of the infarction volume by 62.2% compared to untreated mice. These observations suggest that the polyphenol extract of P. igniarius could serve to prevent ischemic stroke.

  17. Polyphenol extract from Phellinus igniarius protects against acrolein toxicity in vitro and provides protection in a mouse stroke model.

    Science.gov (United States)

    Suabjakyong, Papawee; Saiki, Ryotaro; Van Griensven, Leo J L D; Higashi, Kyohei; Nishimura, Kazuhiro; Igarashi, Kazuei; Toida, Toshihiko

    2015-01-01

    The basidiomycetous mushroom Phellinus igniarius (L.) Quel. has been used as traditional medicine in various Asian countries for many years. Although many reports exist on its anti-oxidative and anti-inflammatory activities and therapeutic effects against various diseases, our current knowledge of its effect on stroke is very limited. Stroke is a neurodegenerative disorder in which oxidative stress is a key hallmark. Following the 2005 discovery by Igarashi's group that acrolein produced from polyamines in vivo is a major cause of cell damage by oxidative stress, we now describe the effects of anti-oxidative extracts from P. igniarius on symptoms of experimentally induced stroke in mice. The toxicity of acrolein was compared with that of hydrogen peroxide in a mouse mammary carcinoma cell line (FM3A). We found that the complete inhibition of FM3A cell growth by 5 μM acrolein could be prevented by crude ethanol extract of P. igniarius at 0.5 μg/ml. Seven polyphenol compounds named 3,4-dihydroxybenzaldehyde, 4-(3,4-dihydroxyphenyl-3-buten-2one, inonoblin C, phelligridin D, inoscavin C, phelligridin C and interfungin B were identified from this ethanolic extract by LCMS and 1H NMR. Polyphenol-containing extracts of P. igniarius were then used to prevent acrolein toxicity in a mouse neuroblastoma (Neuro-2a) cell line. The results suggested that Neuro-2a cells were protected from acrolein toxicity at 2 and 5 μM by this polyphenol extract at 0.5 and 2 μg/ml, respectively. Furthermore, in mice with experimentally induced stroke, intraperitoneal treatment with P. igniarius polyphenol extract at 20 μg/kg caused a reduction of the infarction volume by 62.2% compared to untreated mice. These observations suggest that the polyphenol extract of P. igniarius could serve to prevent ischemic stroke. PMID:25811373

  18. Catalyzed Hydrolysis of RNA by Metallic Complexes of vative%β-环糊精衍生物的金属配合物催化RNA的水解

    Institute of Scientific and Technical Information of China (English)

    宋发军; 丁志刚; 黄文胜; 张先明; 金文闻

    2001-01-01

    用β-环糊精(β-CD)与马来酸酐合成了双(6-氧-丁烯二酸单脂)-β-CD(简称E1), 用KI对E1进行取代, 生成了双(6-碘)-β-CD, 其与组氨酸在NaOH溶液中反应, 生成双(6-氮-组胺酸)-β-CD(简称E2), E2分别与 Mg(Ⅱ)、 Zn(Ⅱ)、 Fe(Ⅱ)和Fe(Ⅲ)形成配合物. 研究了这4种金属配合物对RNA的水解, 并与NaOH水解RNA进行了比较, 发现E2*Fe(Ⅲ)对RNA的水解能力可达到NaOH水解RNA能力的96.9%.%β-Cyclodextrin reacts with maleic anhydride to give bis(6-oxygen-butene diacid ester)-β-cyclodextrin(E1), which reacts with potassium iodide and forms bis(6-iodine)-β-cyclodextrin, which reacts with histidine and forms bis(6-nitrogen-histidine)-β-Cyclodextrin(E2). Metallic complexes are formed by E2 with Mg(Ⅱ)、 Zn(Ⅱ)、 Fe(Ⅱ) and Fe(Ⅲ), respectively, their hydrolysis capability to RNA with sodium hydrate are studied and compared. The results of the research work shows that the hydrolysis capability of E2*Fe(Ⅲ) reaches 96.9% of sodium hydroxide.

  19. PMo or PW heteropoly acids supported on MCM-41 silica nanoparticles: Characterisation and FT-IR study of the adsorption of 2-butanol

    International Nuclear Information System (INIS)

    Mesoporous silica, prepared in basic conditions, has been loaded (20% weight) with 12-molybdophosphoric (PMo) or 12-tungstophosphoric (PW) acid and calcined at different temperatures ranging between 250 and 550 deg. C. The samples have been characterised by N2 adsorption-desorption at -196 deg. C, transmission electron microscopy (TEM), powder X-ray diffraction (PXRD), UV-visible diffuse reflectance, Raman spectroscopy and temperature programmed reduction (TPR). The acidity and catalytic activity have been, respectively, examined by monitoring the adsorption of pyridine and 2-butanol by FT-IR spectroscopy. The results indicate that PW and PMo acids are highly dispersed on mesoporous silica MCM-41 spherical nanoparticles. While PMo retains its Keggin structure up to 550 deg. C, PW decomposes at this temperature into crystalline WO3 and phosphorous oxides. In both cases, the morphology, hexagonal symmetry and long-range order observed for the support are preserved with calcination up to 450 deg. C. The Broensted-type acid sites found in all samples, whose surface concentration decreases as the calcination temperature increases, are responsible for the selective formation of cis-butene detected upon adsorption of 2-butanol. The sample containing PW calcined at 450 deg. C also shows selectivity to methyl ethyl ketone. - Graphical abstract: Samples based in MCM-41 nanoparticles loaded with tungstophosphoric and molybdophosphoric acids have been synthesised. The uncalcined solids and that derived upon their calcination in the temperature range 250-550 deg. C have been characterised and evaluated in the decomposition of 2-butanol monitored by FT-IR spectroscopy

  20. On-board measurements of gaseous pollutant emission characteristics under real driving conditions from light-duty diesel vehicles in Chinese cities.

    Science.gov (United States)

    Wang, Gang; Cheng, Shuiyuan; Lang, Jianlei; Li, Song; Tian, Liang

    2016-08-01

    A total of 15 light-duty diesel vehicles (LDDVs) were tested with the goal of understanding the emission factors of real-world vehicles by conducting on-board emission measurements. The emission characteristics of hydrocarbons (HC) and nitrogen oxides (NOx) at different speeds, chemical species profiles and ozone formation potential (OFP) of volatile organic compounds (VOCs) emitted from diesel vehicles with different emission standards were analyzed. The results demonstrated that emission reductions of HC and NOx had been achieved as the control technology became more rigorous from Stage I to Stage IV. It was also found that the HC and NOx emissions and percentage of O2 dropped with the increase of speed, while the percentage of CO2 increased. The abundance of alkanes was significantly higher in diesel vehicle emissions, approximately accounting for 41.1%-45.2%, followed by aromatics and alkenes. The most abundant species were propene, ethane, n-decane, n-undecane, and n-dodecane. The maximum incremental reactivity (MIR) method was adopted to evaluate the contributions of individual VOCs to OFP. The results indicated that the largest contributors to O3 production were alkenes and aromatics, which accounted for 87.7%-91.5%. Propene, ethene, 1,2,4-trimethylbenzene, 1-butene, and 1,2,3-trimethylbenzene were the top five VOC species based on their OFP, and accounted for 54.0%-64.8% of the total OFP. The threshold dilution factor was applied to analyze the possibility of VOC stench pollution. The majority of stench components emitted from vehicle exhaust were aromatics, especially p-diethylbenzene, propylbenzene, m-ethyltoluene, and p-ethyltoluene. PMID:27521933

  1. Active groups for oxidative activation of C-H bond in C{sub 2}-C{sub 5} paraffins on V-P-O catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Zazhigalov, V.A. [AN Ukrainskoj SSR, Kiev (Ukraine). Inst. Fizicheskoj Khimii

    1998-12-31

    For the first time in scientific literature, in our joint work with Dr. G. Ladwig in 1978 it was established phase portraite of the oxide vanadium-phosphorus system within wide range of P/V ratios from 0.5 to 3.2. Some later those data were confirmed. By investigation of the properties of individual vanadium-phosphorus phases it was also shown that the active component of such catalysts in n-butane oxidation was vanadyl pyrophosphate phase (VO){sub 2}Pr{sub 2}O{sub 7}. From then the conclusion has been evidenced by numerous publications and at present it has been out of doubt practically all over the world. It was hypothized that the unique properties of (VO){sub 2}P{sub 2}O{sub 7} in the reaction of n-butane oxidation could be explained by the presence of paired vanadyl groups and nearness of the distances between neighbouring vanadyl pairs and that between the first and fourth carbon atoms in n-butane molecule. The molecule activation occured at the latter atoms by proton abstraction. A comparison of the results on n-butane and butenes oxidation over vanadyl pyrophosphate allowed to conclude that the paraffin oxidation did not take place due to the molecule dehydrogenation process at the first stage of its conversion. Up to now, more than 100 papers related to paraffins oxidation over vanadyl pyrophosphate and the physico-chemical properties of the catalyst have been published. The process of n-butane oxidation is realized in practice. But still, the question about the nature of active sites of the catalyst and the reaction mechanism remains open and provokes further investigations. The present paper deals with our opinion about the problem and the experimental results supporting it. (orig.)

  2. Bioactivation of 4-ipomeanol by CYP4B1: adduct characterization and evidence for an enedial intermediate.

    Science.gov (United States)

    Baer, Brian R; Rettie, Allan E; Henne, Kirk R

    2005-05-01

    4-Ipomeanol (IPO) is a pneumotoxin that is bioactivated to a reactive intermediate that binds to DNA and other cellular macromolecules. Despite over 30 years of research in this area, detailed structural information on the nature of the IPO reactive intermediate is still lacking. In the present study, we reacted IPO with rabbit CYP4B1 in the presence of exogenous nucleophiles and analyzed the products by liquid chromatography/electrospray ionization-mass spectrometry. Coincubation of IPO and rabbit CYP4B1 with glutathione gave rise to multiple products due likely to the presence of both sulfur and nitrogen nucleophiles in the same trapping molecule. Reaction mixtures containing equimolar N-acetyl cysteine (NAC) and N-acetyl lysine (NAL) provided a major NADPH- and CYP4B1-dependent product. A combination of high-resolution mass spectrometry and two-dimensional NMR analysis following large-scale isolation of the biologically derived material provided evidence for an N-substituted cysteinyl pyrrole derivative of IPO, analogous to that characterized previously in model chemical studies conducted with cis-2-butene-1,4-dial. Purified native rabbit lung CYP4B1 and purified recombinant rabbit CYP4B1 produced the trapped NAC/NAL-IPO pyrrole adduct at rates of 600-700 nmol/nmol P450/30 min. A panel of 14 commercially available recombinant human CYPs was also studied, and substantial rates of IPO bioactivation (>100 nmol/nmol/30 min) were observed with CYP1A2, CYP2C19, CYP2D6, and CYP3A4. These studies provide evidence for the formation of an enedial reactive intermediate during CYP-mediated IPO bioactivation, identify multiple human liver P450s capable of IPO bioactivation, and demonstrate that the same reactive intermediate is formed by both rabbit CYP4B1 and human P450s. PMID:15892579

  3. Novel modified zeolites for energy-efficient hydrocarbon separations.

    Energy Technology Data Exchange (ETDEWEB)

    Arruebo, Manuel (University of Colorado, Boulder, CO); Dong, Junhang; Anderson, Thomas (Burns and McDonnell, Kansas City, MO); Gu, Xuehong; Gray, Gary (Goodyear Chemical Company, Akron, OH); Bennett, Ron (Goodyear Chemical Company, Akron, OH); Nenoff, Tina Maria; Kartin, Mutlu; Johnson, Kaylynn (Goodyear Chemical Company, Akron, OH); Falconer, John (University of Colorado, Boulder, CO); Noble, Richard (University of Colorado, Boulder, CO)

    2006-11-01

    We present synthesis, characterization and testing results of our applied research project, which focuses on the effects of surface and skeletal modification of zeolites for significant enhancements in current hydrocarbon (HC) separations. Zeolites are commonly used by the chemical and petroleum industries as catalysts and ion-exchangers. They have high potential for separations owing to their unique pore structures and adsorption properties and their thermal, mechanical and chemical properties. Because of zeolites separation properties, low cost, and robustness in industrial process, they are natural choice for use as industrial adsorbents. This is a multidisciplinary effort to research, design, develop, engineer, and test new and improved materials for the separation of branched vs. linear organic molecules found in commercially important HC streams via adsorption based separations. The focus of this project was the surface and framework modification of the commercially available zeolites, while tuning the adsorption properties and the selectivities of the bulk and membrane separations. In particular, we are interested with our partners at Goodyear Chemical, on how to apply the modified zeolites to feedstock isoprene purification. For the characterization and the property measurements of the new and improved materials powder X-ray diffraction (PXRD), Residual Gas Analyzer-Mass Spectroscopy (RGA-MS), Electron Microscopy (SEM/EDAX), temperature programmed desorption (TPD) and surface area techniques were utilized. In-situ carbonization of MFI zeolite membranes allowed for the maximum separation of isoprene from n-pentane, with a 4.1% enrichment of the binary stream with n-pentane. In four component streams, a modified MFI membrane had high selectivities for n-pentane and 1-3-pentadiene over isoprene but virtually no separation for the 2-methyl-2-butene/isoprene pair.

  4. A metabolomics strategy to explore urinary biomarkers and metabolic pathways for assessment of interaction between Danhong injection and low-dose aspirin during their synergistic treatment.

    Science.gov (United States)

    Li, Jianping; Guo, Jianming; Shang, Erxin; Zhu, Zhenhua; Zhu, Kevin Yue; Li, Shujiao; Zhao, Buchang; Jia, Lifu; Zhao, Jing; Tang, Zhishu; Duan, Jinao

    2016-07-15

    The drug combination of Danhong injection (DHI) and low-dose aspirin (ASA) was frequently applied for the treatment of cardiovascular and cerebrovascular diseases. Due to the drug interactions, a lot of potential benefits and risks might exist side by side in the course of combination therapy. However, there had been no studies of interaction between DHI and ASA. Metabolomics was a powerful tool to explore endogenous biomarkers and metabolic pathways. In present study, metabolic profiling with ultra-high-performance liquid chromatography coupled to quadrupole time of flight mass spectrometry (UHPLC-QTOF/MS) coupled with multivariate statistical analysis was performed to provide insight into understanding the interaction between DHI and low-dose ASA. Eleven potential biomarkers of three types were identified and seven metabolic pathways were constructed. The results showed that the interaction between DHI and low-dose ASA during synergistic treatment indeed affected some key endogenous biomarkers and metabolic pathways, which could not happen when DHI or low-dose ASA was used alone. The quality and quantity of endogenous metabolite were both influenced by interaction between DHI and low-dose ASA. In details, the amount of flavin mononucleotide, L-2, 4-diaminobutyric acid (DABA) and 4-aminohippuric acid were significantly increased. On the contrary, the amount of 3-methyluridine, 4, 6-dihydroxyquinoline, cortolone-3-glucuronide, and serotonin were significantly decreased. Furthermore, O-phosphotyrosine, 3-methyl-2-butenal, indoxyl sulfate and dolichyl diphosphate were disappeared in urine. As to metabolic pathways, riboflavin metabolism, pentose and glucuronate interconversions, and tryptophan metabolism were all significantly influenced. The emerging alterations of biomarkers and metabolic pathways were associated with a lot of drugs and diseases based on literature researches, which might influence the co-administration of other drugs or the treatments of relevant

  5. DESIGN AND PARAMETRIC OPTIMIZATION OF AN ORGANIC RANKINE CYCLE POWERED BY SOLAR ENERGY

    Directory of Open Access Journals (Sweden)

    Francesco Calise

    2013-01-01

    Full Text Available This study presents the simulation and performance analysis of a regenerative and superheated Organic Rankine Cycle (ORC. To this scope, anew simulation model has been developed. The model is based on zero-dimensional energy and mass balances for all the components of the system. Shell and tube heat expanders with single shell and double tube pass have been chosen. Pump and expander have been considered only form a thermodynamic point of view, with constant compressor and expansion efficiency. The simulations have been carried out in order to find different optimization criteria to use as preliminary design tools, especially for the organic fluid choice and the heat exchanger design. Firstly, the ORC performances have been evaluated for different organic medium, varying the temperature of the heat source. The global efficiency of the plant, the net electric power generation and the volumetric expansion ratio has been considered as evaluation parameters. The simulation results show that two hydrocarbons demonstrate good performance for low, medium and high heat source, namely Isobutene, n-Butene; R245fa can add to them for the exploitation of heat source up to 170°C. Additional simulations have been carried out to discover an optimization criterion for the heat exchanger design. The plant performances have been first evaluated varying one by one the following parameters: tube length, tube number and shell diameter. Then a global optimization was also performed using the Golden Search technique. The total cost of the plant has been considered as objective functions. With respect to the objective function, higher the boiling heat transfer area higher the electric power generation and the economical benefit. The optimal configuration, compared to the initial one, shows an increase of incomes and mechanical power equal to 60.1 and 48.2% respectively, against a decrease of global efficiency equal to 10.9%.

  6. Potato wound-healing tissues: A rich source of natural antioxidant molecules with potential for food preservation.

    Science.gov (United States)

    Dastmalchi, Keyvan; Wang, Isabel; Stark, Ruth E

    2016-11-01

    The need for safe, effective preservatives is a prominent issue in the food and drug industries, reflecting demand for natural alternatives to synthetic chemicals viewed as harmful to consumers and the environment. Thus, this study determined the identities and scavenging capacities of antioxidant metabolites produced as a response to potato tuber wounding, using activity-guided fractionation of polar extracts from a Yukon Gold cultivar that had previously exhibited exceptionally high radical-scavenging activity. Activity-guided fractionation using the ABTS(+) radical scavenging assay and LC-MS with TOF-MS for compositional analysis of the most potent antioxidant fractions yielded identification of nine constituents: coumaroylputrescine; feruloylquinic acid; isoferuloylputrescine; ferulic acid; 22,25-dimethoxy-3-[[2,3,4-tri-O-methyl-6-O-(2,3,4,6-tetra-O-methyl-β-d-glucopyranosyl)-β-d-glucopyranosyl]oxy]-(3β)-lanost-9(11)-en-24-one; 4-(2Z)-2-decen-1-yl-5-[1-(4-hydroxyphenyl)decyl]-1,2-benzenediol; 8-[(2E)-3,7-dimethyl-2,6-octadien-1-yl]-5-hydroxy-2,8-dimethyl-6-(3-methyl-2-buten-1-yl)-2H-1-benzopyran-4,7(3H,8H)-dione; 3-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]-20-[(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl)oxy]-dammar-24-en-19-al; (3β)-28-oxo-28-(phenylmethoxy)oleanan-3-yl 2-O-β-d-galactopyranosyl-3-O-(phenylmethyl)-, butyl ester β-d-glucopyranosiduronic acid. A positive correlation was observed between the scavenging activities and the polarities of the active fractions. The antioxidant capacities of the fractions were also characterised by monitoring the activity throughout a 45-minute assay period. PMID:27211673

  7. Applications of direct methods for structure determination to problems in electron and x-ray fibre diffraction of polymers

    International Nuclear Information System (INIS)

    In this review, the prospect of determining polymer crystal structures directly from single crystal electron or x-ray powder/fibre diffraction intensity data is explored. When care is taken to collect the best data set from a polymer, i.e. sampling the most intense regions of the three-dimensional reciprocal lattice, structure analyses can be carried out effectively by the conventional direct phasing methods employed in small molecule crystallography, even though the data sets are relatively small. This means that constraints imposed by multiple beam interactions in electron diffraction and reflection overlap in x-ray diffraction often do not limit the structure analysis. Several three-dimensional single crystal electron diffraction structure analyses are presented to illustrate the problems encountered. These include: polyethylene, poly(ε-caprolactone), isotactic poly(butene-1) form III, isotactic polypropylene β-form, poly(p-oxybenzoate) and poly(ethylene sulfide). Techniques for sampling the complete reciprocal lattice are discussed. If an adequate number of data is collected, it is also possible to refine the structure by constrained least squares. In any case Fourier refinement is always useful. From powder x-ray diffraction the crystal structure of polyethylene has been determined by direct methods; from fibre x-ray intensities, this review reports the direct analyses of poly(ε-caprolactone), poly(ethylene terephthalate) and poly(tetramethyl-p-silphenylene siloxane). Rietveld methods might also be useful for the structure refinement. Direct structure analyses are advantageous in that they circumvent a priori assumptions about the molecular model and also the linkage bonds to base conformational refinement. Instead, individual atomic positions or molecular envelopes are observed directly in potential or electron density maps, to which the model can then be fit, a situation analogous to current practice in protein crystallography

  8. Dehydration of isobutanol to isobutene in a slurry reactor

    Energy Technology Data Exchange (ETDEWEB)

    Latshaw, B.E.

    1994-02-01

    The April 1990 Alternative Fuels Proposal to the Department of Energy involved the development of new technology, based on the liquid phase process, for conversion of coal-derived synthesis gas to oxygenated hydrocarbon fuels, fuel additives, and fuel intermediates. The objective of this work was to develop a slurry reactor based process for the dehydration of isobutanol to isobutene. The isobutene can serve as a feedstock for the high octane oxygenated fuel additive methyl tertiary-butyl either (MTBE). Alumina catalysts were investigated because of their wide use as a dehydration catalyst. Four commercially available alumina catalysts (Catapal B, Versal B, Versal GH, and Al-3996R) were evaluated for both activity and selectivity to the branched olefin. All four catalysts demonstrated conversions greater than 80% at 290 C, while conversions of near 100% could be obtained at 330 C. The reaction favors low pressures and moderate to low space velocities. A yield of 0.90 mole isobutene per mole reacted isobutanol or better was obtained at conversions of 60--70% and higher. From 75 to 98% conversion, the four catalysts all provide isobutene yields ranging from 0.92 to 0.94 with the maximum occurring around 90% conversion. At low conversions, the concentration of diisobutyl ether becomes significant while the concentration of linear butenes is essentially a linear function of isobutanol conversion. Doping the catalyst with up to 0.8 wt % potassium showed a modest increase in isobutene selectivity; however, this increase was more than offset by a reduction in activity. Investigations using a mixed alcohols feed (consistent with isobutanol synthesis from syngas) demonstrated a small increase in the C4 iso-olefin selectivity over that observed for a pure isobutanol feed. 55 refs.

  9. Effects of Calcination Temperature on the Acidity and Catalytic Performances of HZSM-5 Zeolite Catalysts for the Catalytic Cracking of n-Butane

    Institute of Scientific and Technical Information of China (English)

    Jiangyin Lu; Zhen Zhao; Chunming Xu; Aijun Duan; Pu Zhang

    2005-01-01

    The acidic modulations of a series of HZSM-5 catalysts were successfully made by calcination at different treatment temperatures, i.e. 500, 600, 650, 700 and 800 ℃, respectively. The results indicated that the total acid amounts, their density and the amount of B-type acid of HZSM-5 catalysts rapidly decreased, while the amounts of L-type acid had almost no change and thus the ratio of L/B was obviously enhanced with the increase of calcination temperature (excluding 800 ℃). The catalytic performances of modified HZSM-5 catalysts for the cracking of n-butane were also investigated. The main properties of these catalysts were characterized by means of XRD, N2 adsorption at low temperature, NH3-TPD, FTIR of pyridine adsorption and BET surface area measurements. The results showed that HZSM-5 zeolite pretreated at 800 ℃ had very low catalytic activity for n-butane cracking. In the calcination temperature range of 500-700 ℃, the total selectivity to olefins, propylene and butene were increased with the increase of calcination temperature, while, the selectivity for arene decreased with the calcination temperature.The HZSM-5 zeolite calcined at 700 ℃ produced light olefins with high yield, at the reaction temperature of 650 ℃ the yields of total olefins and ethylene were 52.8% and 29.4%, respectively. Besides, the more important role is that high calcination temperature treatment improved the duration stability of HZSM-5zeolites. The effect of calcination temperature on the physico-chemical properties and catalytic performance of HZSM-5 for cracking of n-butane was explored. It was found that the calcination temperature had large effects on the surface area, crystallinity and acid properties of HZSM-5 catalyst, which further affected the catalytic performance for n-butane cracking.

  10. Are styrene oligomers in coastal sediments of an industrial area aryl hydrocarbon-receptor agonists?

    Science.gov (United States)

    Hong, Seongjin; Lee, Junghyun; Lee, Changkeun; Yoon, Seo Joon; Jeon, Seungyeon; Kwon, Bong-Oh; Lee, Jong-Hyeon; Giesy, John P; Khim, Jong Seong

    2016-06-01

    Effect-directed analysis (EDA) was performed to identify the major aryl hydrocarbon receptor (AhR) agonists in sediments collected from a highly industrialized area (Lake Shihwa, Korea). Great AhR-mediated potencies were found in fractions containing aromatic compounds with log Kow values of 5-8, and relatively great concentrations of styrene oligomers (SOs) and polycyclic aromatic hydrocarbons (PAHs) were detected in those fractions. Until now, there was little information on occurrences and toxic relative potencies (RePs) of SOs in coastal environments. In the present study; i) distributions and compositions, ii) AhR binding affinities, and iii) contributions of SOs to total AhR-mediated potencies were determined in coastal sediments. Elevated concentrations of 10 SOs were detected in sediments of inland creeks ranging from 61 to 740 ng g(-1) dry mass (dm), while lesser concentrations were found in inner (mean = 33 ng g(-1) dm) and outer regions (mean = 25 ng g(-1) dm) of the lake. Concentrations of PAHs in sediments were comparable to those of SOs. 2,4-diphenyl-1-butene (SD3) was the predominant SO analogue in sediments. SOs and PAHs were accumulated in sediments near sources, and could not be transported to remote regions due to their hydrophobicity. RePs of 3 SOs could be derived, which were 1000- to 10,000-fold less than that of one representative potent AhR active PAH, benzo[a]pyrene. Although concentrations of SOs in sediments were comparable to those of PAHs, the collective contribution of SOs to total AhR-mediated potencies were rather small (plastic in the coastal environment. PMID:27043777

  11. Effect of (+)-limonene and 1-methoxy-2-propanol on Ips typographus response to pheromone blends

    Institute of Scientific and Technical Information of China (English)

    Miroslav Bla(z)enec; Rastislav Jaku(s)

    2009-01-01

    We compared two different strategies to increase the catches of Ips typographus (L.), particularly males, in pheromone-baited traps. The first of these strategies, the barrier approach, used alternating pheromone blends, targeting males and females respectively, in closely-spaced traps forming a barrier around forest stands. The second strategy, the single trap approach, used widely-spaced traps that were all baited with the same lure and intended to trap the highest possible numbers of males without compromising trapping of females. In the blend used for the barrier traps targeting primarily males, with a lower percentage of (4S)-cis-verbenol (cV), the (-)-α-pinene was replaced step wise with (+)-limonene at rates of 0%, 1%, 10%, 35%, 60% and 90%. This replacement had no significant effect on the numbers of responding I. Typographus males, but there was a slight effect on the percentage of males caught. In the attractant blend for the barrier traps targeting females, with a higher percentage of cV, the 2-methyl-3-buten-2-ol (MB) was replaced with 1-methoxy-2-propanol (MP) in a similar fashion as for the male-specific blends. The replacement did not significantly affect the catch of females. Thus, it is possible to use the MP in the blend with cV and ipsdienol without significant change in catch efficacy. In the blends for single traps, the (-)-α-pinene was replaced with (+)-limonene and MB with MP. The replacement of (-)-α-pinene had only a slight effect on the percentage of males, but the results suggest that replacing MB with MP in the blend will not significantly reduce trapping efficacy.

  12. Effect of the Inclusion of Chestnut in the Finishing Diet on Volatile Compounds of Dry-Cured Ham from Celta Pig Breed

    Institute of Scientific and Technical Information of China (English)

    Jos M. Lorenzo; Javier Carballo; Daniel Franco

    2013-01-01

    The effect of the inclusion of chestnut in pigs ifnishing diet on volatile compounds of dry-cured Celta ham was studied. Twelve hams of each type (from three different pigs ifnishing diets:concentrate (CO), mixed (MI) and chestnut (CH)) were used. Volatiles were extracted using a purge-and-trap method and analyzed by gas chromatography/mass spectrometry (GC/MS). Thirty-nine volatile compounds were identified in dry-cured Celta ham samples. Most abundant volatiles in ham samples were aldehydes, which represented respectively, 53% (CO), 51% (MI) and 46% (CH) of the total volatile composition. With the exception of 2-butenal, 2-methyl, all aldehydes were affected by feeding system. On the other hand, hydrocarbons n-alkanes were the second major group in the volatile proifle of dry-cured Celta hams and represented 28.9, 35.7 and 32.4%of the total volatile composition for CO, MI and CH groups, respectively. Ham samples from chestnut group showed a higher content of alcohols and this result could be related with the inclusion of chestnut in the ifnishing diet of pigs. Principal component analysis showed a good separation among groups. The discriminant analysis selected eight variables (butanoic acid, hexanal, octanal, nonenal (E), decenal (E), tetradecane, decane trimethyl and pyridine 2-methyl) and calculated two discriminating functions to predict if chestnut has been included in the ifnishing diet. Thus, it was possible to discriminate between groups fed with ifnishing diets containing chestnuts in their composition (mixed and chestnut group).

  13. Use of ferric sulfate: acid media for the desulfurization of model compounds of coal. [Dibenzothiophene, diphenyl sulfide, di-n-butyl sulfide

    Energy Technology Data Exchange (ETDEWEB)

    Clary, L.R.; Vermeulen, T.; Lynn, S.

    1980-12-01

    The objective of this work has been to investigate the ability of ferric sulfate-acid leach systems to oxidize the sulfur in model compounds of coal. Ferric iron-acid leach systems have been shown to be quite effective at removal of inorganic sulfur in coal. In this study, the oxidative effect of ferric iron in acid-leach systems was studied using dibenzothiophene, diphenyl sulfide, and di-n-butyl sulfide as models of organic sulfur groups in coal. Nitrogen and oxygen, as well as various transition metal catalysts and oxidants, were utilized in this investigation. Dibenzothiophene was found to be quite refractory to oxidation, except in the case where metavanadate was added, where it appears that 40% oxidation to sulfone could have occurred per hour at 150/sup 0/C and mild oxygen pressure. Diphenyl sulfide was selectively oxidized to sulfoxide and sulfone in an iron and oxygen system. Approximately 15% conversion to sulfone occurred per hour under these conditions. Some of the di-n-butyl sulfide was cracked to 1-butene and 1-butanethiol under similar conditions. Zinc chloride and ferric iron were used at 200/sup 0/C in an attempt to desulfonate dibenzothiophene sulfone, diphenyl sulfone, and di-n-butyl sulfone. Di-n-butyl sulfone was completely desulfurized on one hour and fragmented to oxidized parafins, while dibenzothiophene sulfone and diphenyl sulfone were unaffected. These results suggest that an iron-acid leach process could only selectively oxidize aryl sulfides under mild conditions, representing only 20% of the organic sulfur in coal (8% of the total sulfur). Removal through desulfonation once selective sulfur oxidation had occurred was only demonstrated for alkyl sulfones, with severe oxidation of the fragmented paraffins also occurring in one hour.

  14. Selective hydrogenation of 2-methyl-3-butyn-2-ol catalyzed by embedded polymer-protected PdZn nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Okhlopkova, Lyudmila B., E-mail: mila65@catalysis.ru; Matus, Ekaterina V.; Prosvirin, Igor P.; Kerzhentsev, Michail A.; Ismagilov, Zinfer R. [Boreskov Institute of Catalysis (Russian Federation)

    2015-12-15

    PdZn/TiO{sub 2} catalysts were synthesized by sol–gel method using a template Pluronic F127. PdZn nanoparticles with the size ranging from 1.7 to 2 nm were prepared by ethylene glycol reduction of ZnCl{sub 2} and Pd(CH{sub 3}COO){sub 2} in the presence of stabilizer and introduced into the matrix by addition into TiO{sub 2} sol, followed by different activation procedures. The structure, particles size, and chemical composition of nanoparticles and catalysts were characterized by transmission electron microscopy, X-ray photoelectron spectroscopy, X-ray fluorescence spectroscopy, and energy dispersive spectroscopy. The prepared catalysts have been tested in the selective hydrogenation of 2-methyl-3-butyn-2-ol, and the results have been compared with catalysts prepared by conventional impregnation. The results indicate that bimetallic PdZn nanoparticles-based catalysts show higher selectivity than corresponding monometallic Pd/TiO{sub 2}. Embedded on titania, bimetallic nanoparticles stabilized with polyvinylpyrrolidone exhibit good activity (1.1–1.8 mol MBY/mol Pd/s{sup −1}) and high selectivity to 2-methyl-3-buten-2-ol (81.5–88.9 % at 95 % conversion). The influence of the nature of the stabilizer, the stabilizer/metal molar ratio, and activation conditions on the catalytic behavior of the samples was analyzed. It is shown that the particle size does not significantly affect the catalytic properties in the range of 4.4–6.5 nm. The nature and amount of stabilizer seem to be crucial to prepare efficient catalyst.

  15. Methyl chavicol: characterization of its biogenic emission rate, abundance, and oxidation products in the atmosphere

    Directory of Open Access Journals (Sweden)

    N. C. Bouvier-Brown

    2008-11-01

    Full Text Available We report measurements of ambient atmospheric mixing ratios for methyl chavicol and determine its biogenic emission rate. Methyl chavicol, a biogenic oxygenated aromatic compound, is abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol was detected simultaneously by three in-situ instruments – a gas chromatograph with mass spectrometer detector (GC-MS, a proton transfer reaction mass spectrometer (PTR-MS, and a thermal desorption aerosol GC-MS (TAG – and found to be abundant within and above Blodgett Forest, a ponderosa pine forest in the Sierra Nevada Mountains of California. Methyl chavicol atmospheric mixing ratios are strongly correlated with 2-methyl-3-buten-2-ol (MBO, a light- and temperature-dependent biogenic emission from the ponderosa pine trees at Blodgett Forest. Scaling from this correlation, methyl chavicol emissions account for 4–68% of the carbon mass emitted as MBO in the daytime, depending on the season. From this relationship, we estimate a daytime basal emission rate of 0.72–10.2 μgCg−1h−1, depending on needle age and seasonality. We also present the first observations of its oxidation products (4-methoxybenzaldehyde and 4-methyoxy benzene acetaldehyde in the ambient atmosphere. Methyl chavicol is a major essential oil component of many plant species. This work suggests that methyl chavicol plays a significant role in the atmospheric chemistry of Blodgett Forest, and potentially other sites, and should be included explicitly in both biogenic volatile organic carbon emission and atmospheric chemistry models.

  16. Cl atom initiated oxidation of 1-alkenes under atmospheric conditions

    Science.gov (United States)

    Walavalkar, M.; Sharma, A.; Alwe, H. D.; Pushpa, K. K.; Dhanya, S.; Naik, P. D.; Bajaj, P. N.

    2013-03-01

    In view of the importance of the oxidation pathways of alkenes in the troposphere, and the significance of Cl atom as an oxidant in marine boundary layer (MBL) and polluted industrial atmosphere, the reactions of four 1-alkenes (C6-C9) with Cl atoms are investigated. The rate coefficients at 298 K are measured to be (4.0 ± 0.5), (4.4 ± 0.7), (5.5 ± 0.9) and (5.9 ± 1.7) × 10-10 cm3 molecule-1 s-1 for 1-hexene, 1-heptene, 1-octene and 1-nonene, respectively. The quoted errors include the experimental 2σ, along with the error in the reference rate coefficients. From the systematic increase in the rate coefficients with the number of carbon atoms, an approximate value for the average rate coefficient for hydrogen abstraction per CH2 group in alkenes is estimated to be (4.9 ± 0.3) × 10-11 cm3 molecule-1 s-1. Based on these rate coefficients, the contribution of Cl atom reactions towards the degradation of these molecules is found to be comparable to that of OH radical reactions, under MBL conditions. The products identified in gas phase indicate that Cl atom addition occurs mainly at the terminal carbon, leading to the formation of 1-chloro-2-ketones and 1-chloro-2-ols. The major gas phase products from the alkenyl radicals (formed by H atom abstraction) are different positional isomers of long chain enols and enones. A preference for dissociation leading to an allyl radical, resulting in aldehydes, lower by three carbon atoms, is indicated. The observed relative yields suggest that in general, the increased contribution of the reactions of Cl atoms towards degradation of 1-alkenes in NOx free air does not result in an increase in the generation of small aldehydes (carbon number < 4), including chloroethanal, as compared to that in the reaction of 1-butene.

  17. Formation and chemical reactivity of carbon fibers prepared by defluorination of graphite fluoride

    Science.gov (United States)

    Hung, Ching-Cheh

    1994-01-01

    Defluorination of graphite fluoride (CFX) by heating to temperatures of 250 to 450 C in chemically reactive environments was studied. This is a new and possibly inexpensive process to produce new carbon-based materials. For example, CF 0.68 fibers, made from P-100 carbon fibers, can be defluorinated in BrH2C-CH = CH-CH2Br (1,4-dibromo-2butene) heated to 370 C, and graphitized to produce fibers with an unusually high modulus and a graphite layer structure that is healed and cross-linked. Conversely, a sulfur-doped, visibly soft carbon fiber was produced by defluorinating CF 0.9 fibers, made from P-25, in sulfur (S) vapor at 370 C and then heating to 660 C in nitrogen (N2). Furthermore, defluorination of the CF 0.68 fibers in bromine (Br2) produced fragile, structurally damaged carbon fibers. Heating these fragile fibers to 1100 C in N2 caused further structural damage, whereas heating to 150 C in bromoform (CHBr3) and then to 1100 C in N2 healed the structural defects. The defluorination product of CFX, tentatively called activated graphite, has the composition and molecular structure of graphite, but is chemically more reactive. Activated graphite is a scavenger of manganese (Mn), and can be intercalated with magnesium (Mg). Also, it can easily collect large amounts of an alloy made from copper (Cu) and type 304 stainless steel to form a composite. Finally, there are indications that activated graphite can wet metals or ceramics, thereby forming stronger composites with them than the pristine carbon fibers can form.

  18. Design of and initial results from a highly instrumented reactor for atmospheric chemistry (HIRAC

    Directory of Open Access Journals (Sweden)

    D. R. Glowacki

    2007-07-01

    Full Text Available The design of a Highly Instrumented Reactor for Atmospheric Chemistry (HIRAC is described and initial results obtained from HIRAC are presented. The ability of HIRAC to perform in-situ laser-induced fluorescence detection of OH and HO2 radicals with the Fluorescence Assay by Gas Expansion (FAGE technique establishes it as internationally unique for a chamber of its size and pressure/temperature variable capabilities. In addition to the FAGE technique, HIRAC features a suite of analytical instrumentation, including: a multipass FTIR system; a conventional gas chromatography (GC instrument and a GC instrument for formaldehyde detection; and NO/NO2, CO, O3, and H2O vapour analysers. Ray tracing simulations and measurements of the blacklamp flux have been utilized to develop a detailed model of the radiation field within HIRAC. Comparisons between the analysers and the FTIR coupled to HIRAC have been performed, and HIRAC has also been used to investigate pressure dependent kinetics of the chlorine atom reaction with ethene and the reaction of O3 and t-2-butene. The results obtained are in good agreement with literature recommendations and Master Chemical Mechanism predictions. HIRAC thereby offers a highly instrumented platform with the potential for: (1 high precision kinetics investigations over a range of atmospheric conditions; (2 detailed mechanism development, significantly enhanced according to its capability for measuring radicals; and (3 field instrument intercomparison, calibration, development, and investigations of instrument response under a range of atmospheric conditions.

  19. Glucosinolate breakdown products as insect fumigants and their effect on carbon dioxide emission of insects

    Directory of Open Access Journals (Sweden)

    Coats Joel R

    2002-03-01

    Full Text Available Abstract Background Glucosinolate breakdown products are volatile, therefore good candidates for insect fumigants. However, although they are insecticidal, the mode of action of such natural products is not clear. We studied the insecticidal effect of these compounds as fumigants, and monitored the production of carbon dioxide by the insects as a probe to the understanding of their mode of action. Results The fumigation 24-h LC50 against the house fly (Musca domestica L. of allyl thiocyanate, allyl isothiocyanate, allyl cyanide, and l-cyano-2-hydroxy-3-butene was 0.1, 0.13, 3.66, and 6.2 μg cm-3, respectively; they were 0.55, 1.57, 2.8, and > 19.60 μg cm-3, respectively, against the lesser grain borer (Rhyzopertha dominica Fabricius. The fumigation toxicity of some of the glucosinolate products was very close to or better than that of the commercial insect fumigants such as chloropicrin (LC50: 0.08 and 1.3 μg cm-3 against M. domestica and R. dominica, respectively and dichlorovos (LC50: -3 against M. domestica and R. dominica, respectively in our laboratory tests. Significantly increased CO2 expiration was found in insects exposed to the vapor of allyl isothiocyanate, allyl thiocyanate and allyl isocyanate. Allyl isothiocyanate was also found to increase the CO2 expiration of the American cockroach (Periplaneta americana L.. Conclusions Glucosinolate breakdown products have potential as biodegradable and safe insect fumigants. They may act on the insect respiratory system in their mode of action.

  20. AMBIENT HYDROCARBONS IN THE HOUSTON METROPOLITAN AREA DURING TEXAQS 2000: AN IDENTIFICATION OF UNUSUAL FEATURES.

    Energy Technology Data Exchange (ETDEWEB)

    KLEINMAN, L.I.; DAUM P.H.

    2004-11-01

    Houston's ozone problem has been linked to the occurrence of very high light olefin concentrations. We have analyzed the DOE G-1 aircraft hydrocarbon data set to provide additional information on the geographic distribution and prevalence of air samples with high olefin concentration as well as an identification of other compounds which contribute to the high hydrocarbon reactivity in Houston. In order to identify high concentrations we need a definition of normal. For that purpose we use aircraft samples collected during a 1999 aircraft based field campaign in Philadelphia relying on the circumstance that the frequency distributions of NO{sub x} and C{sub 2}H{sub 2} in Philadelphia are nearly the same as in Houston. Comparison is made also with hydrocarbons collected in Phoenix which exhibit nearly the same NO{sub x} and C{sub 2}H{sub 2} frequency distribution as the other 2 cities, but in spite of that similarity have a much lower hydrocarbon reactivity. As in other studies we find that there is a subset of Houston hydrocarbon samples with very high OH-reactivity due to elevated concentrations of ethylene, propylene and less often butenes, including 1,3 butadiene. Although these samples stand out as being qualitatively different we present evidence that ethylene and propylene are significantly elevated in at least half of the Houston samples, covering a wide geographic area apart from the Ship Channel region. Frequency distributions for these compounds are log normal suggesting that Houston's atmosphere is a single entity rather than separate industrial and urban areas. The comparison between Houston and Philadelphia also identifies C{sub 2}-C{sub 5} alkanes, n-hexane, and benzene as having elevated concentrations. Emission reductions of these less reactive compounds sufficient to yield the concentrations observed in Philadelphia would have a minor effect on the most reactive samples, but about a 20% effect on samples with more typical (median

  1. Tempo-spatial variation of emission inventories of speciated volatile organic compounds from on-road vehicles in China

    Directory of Open Access Journals (Sweden)

    H. Cai

    2009-05-01

    Full Text Available Emission inventories of sixty-nine speciated non-methane volatile organic compounds (NMVOC from on-road vehicles in China were estimated for the period of 1980–2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes.

    Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980–2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2781.4, 1244.9, 178.5, 1350.7 and 403.3 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period.

    Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde

  2. Tempo-spatial variation of emission inventories of speciated volatile organic compounds from on-road vehicles in China

    Directory of Open Access Journals (Sweden)

    H. Cai

    2009-09-01

    Full Text Available Emission inventories of sixty-seven speciated non-methane volatile organic compounds (NMVOC from on-road vehicles in China were estimated for the period of 1980–2005, using seven NMVOC emission profiles, which were summarized based on local and international measurements from published literatures dealing with specific vehicle categories running under particular modes.

    Results show an exponential growth trend of China's historical emissions of alkanes, alkenes, alkines, aromatics and carbonyls during the period of 1980–2005, increasing from 63.9, 39.3, 6.9, 36.8 and 24.1 thousand tons, respectively, in 1980 to 2778.2, 1244.5, 178.7, 1351.7 and 406.0 thousand tons, respectively, in 2005, which coincided well with China's economic growth. Emission inventories of alkenes, aromatics and carbonyls were gridded at a high resolution of 40 km×40 km for air quality simulation and health risk evaluation, using the geographic information system (GIS methodology. Spatial distribution of speciated NMVOC emissions shows a clear difference in emission densities between developed eastern and relatively underdeveloped western and inland China. Besides, the appearance and expansion of high-emission areas was another notable characteristic of spatial distribution of speciated NMVOC emissions during the period.

    Emission contributions of vehicle categories to speciated NMVOC groups showed annual variation, due to the variance in the provincial emissions and in the relative fractions of the seven emission profiles adopted at the provincial level. Highly reactive and toxic compounds accounted for high proportions of emissions of speciated NMVOC groups. The most abundant compounds were isopentane, pentane and butane from alkanes; ethene, propene, 2-methyl-2-butene and ethyne from alkenes and alkines; benzene, toluene, ethylbenzene, o-xylene, and m,p-xylene (BTEX and 1,2,4-trimethylbenzene from aromatics and formaldehyde, acetaldehyde

  3. Construction and validation of detailed kinetic models for the combustion of gasoline surrogates; Construction et validation de modeles cinetiques detailles pour la combustion de melanges modeles des essences

    Energy Technology Data Exchange (ETDEWEB)

    Touchard, S.

    2005-10-15

    The irreversible reduction of oil resources, the CO{sub 2} emission control and the application of increasingly strict standards of pollutants emission lead the worldwide researchers to work to reduce the pollutants formation and to improve the engine yields, especially by using homogenous charge combustion of lean mixtures. The numerical simulation of fuel blends oxidation is an essential tool to study the influence of fuel formulation and motor conditions on auto-ignition and on pollutants emissions. The automatic generation helps to obtain detailed kinetic models, especially at low temperature, where the number of reactions quickly exceeds thousand. The main purpose of this study is the generation and the validation of detailed kinetic models for the oxidation of gasoline blends using the EXGAS software. This work has implied an improvement of computation rules for thermodynamic and kinetic data, those were validated by numerical simulation using CHEMKIN II softwares. A large part of this work has concerned the understanding of the low temperature oxidation chemistry of the C5 and larger alkenes. Low and high temperature mechanisms were proposed and validated for 1 pentene, 1-hexene, the binary mixtures containing 1 hexene/iso octane, 1 hexene/toluene, iso octane/toluene and the ternary mixture of 1 hexene/toluene/iso octane. Simulations were also done for propene, 1-butene and iso-octane with former models including the modifications proposed in this PhD work. If the generated models allowed us to simulate with a good agreement the auto-ignition delays of the studied molecules and blends, some uncertainties still remains for some reaction paths leading to the formation of cyclic products in the case of alkenes oxidation at low temperature. It would be also interesting to carry on this work for combustion models of gasoline blends at low temperature. (author)

  4. Observations of BVOC (Biogenic Volatile Organic Compound) Fluxes and Vertical Gradients in a Ponderosa Pine Forest during BEARPEX 2009

    Science.gov (United States)

    Park, J.; Fares, S.; Weber, R.; Goldstein, A.

    2010-12-01

    During summer 2009 an intensive field campaign (Biosphere Effects on AeRosols and Photochemistry EXperiment - BEARPEX) took place in Blodgett Forest, a Ponderosa pine forest in the Sierra Nevada Mountains of California. The campaign aimed to investigate biosphere-atmosphere interactions during a period of intense photochemical activity, to elucidate the fate BVOC (Biogenic Volatile Organic Compounds) in the atmosphere, and explore the processes of secondary organic aerosol formation. In this study, a PTR-MS (Proton Transfer Reaction - Mass Spectrometry) was used to measure 19 compounds (masses) including methanol, isoprene + MBO (2-Methyl-3-butene-2-ol), monoterpenes, sesquiterpenes, and some oxygenated BVOCs at 5 heights of a vertical gradient from the forest floor to above the canopy. Fluxes of the 4 dominant BVOCs were measured above the canopy with the Eddy covariance technique. In parallel with BVOC measurements, ozone fluxes and gradients, and meteorological parameters (PAR, temperature, relative humidity, wind speed, and wind direction) were recorded in order to investigate the dependence of BVOC emissions and chemistry on meteorological conditions and to test the hypothesis that BVOC remove atmospheric ozone through gas-phase reactions. BVOCs which are directly emitted from pine trees generally have the highest concentration at the lowest measurement height and the lowest concentration above the canopy. Sesquiterpenes were observed at lower concentration than monoterpenes, but with very similar vertical gradient patterns, indicating their emission patterns are similar. The observed MBO flux was approximately twice the Monoterpene flux. Measured monoterpene canopy scale flux was consistent with modeled emissions based on scaling up from branch enclosure measurements at this site (basal emission rate F30= 0.61 ±0.14 mgC m-2 hr-1 and temperature response β= 0.15 ±0.09 °C-1). We find that m/z 113, an unidentified OVOCs (oxygenated volatile organic compounds

  5. Estudio Cinético de la Descomposición Térmica de Tres Derivados del Pirano (C5H6O Kinetic Study of the Thermal Decomposition of Three Derived from the Pyran (C5H6O

    Directory of Open Access Journals (Sweden)

    Jennifer J Lafont

    2009-01-01

    Full Text Available El artículo presenta el estudio cinético de descomposición térmica de tres compuestos derivados del pirano que no han sido reportados en la literatura. Estos compuestos son ampliamente utilizados en farmacología y en la obtención de importantes productos a nivel tecnológico e industrial. Los compuestos 2,6-dietoxitetrahidro-2H-pirano; 2-etoxi-6-propoxitetrahidro-2H-pirano y 2-etoxi-6-butoxi-tetrahidro-2H-pirano se escogieron variando el sustituyente ubicado en la posición 6 del núcleo. Cada experimento cinético fue realizado a cinco temperaturas con intervalos de 10 grados en un rango entre 333 a 373 K, utilizando un sistema de reacción a microescala. Se obtuvieron los productos 2-etoxi-6-hidroxi-tetrahidro-2H-pirano y etileno, propeno, o buteno para cada caso, fueron identificados mediante la técnica de cromatografía de gases acoplada a masas. Las reacciones resultaron ser unimoleculares homogéneas y de primer orden. Teniendo en cuenta los parámetros cinéticos y termodinámicos obtenidos, se puede decir que la reacción es compatible con un estado de transición cíclico de seis miembros, concertado y semipolar.The article presents a kinetic study of the thermal decomposition of three compounds derived from pyran that have not been reported in the literature. These compounds are widely used in pharmacology to obtain important products of technological and industrial interest. The compound (2,6-dietoxitetrahydro-2H-pyran; 2-etoxi-6-propoxytetrahydro-2H-pyran and 2-etoxi-6-butoxytetra-hydro-2H-pyran were chosen by varying the substituent located in the 6 position of the nucleus. Each experiment was done at five temperature with intervals of 10 degrees in a range between 333 and 373 K, using a microscale reaction system. The products obtained, 2-etoxy-6-hydroxy-tetrahydro-2H-pyran and ethylene, propene, or butene for each case, were identified using gas chromatography connected to masses. The reactions turned out to be unimolecular

  6. Total OH reactivity measurements at Manitou Experimental Forest in summer season during BEACHON-SRM08

    Science.gov (United States)

    Nakashima, Y.; Kato, S.; Kajii, Y.; Greenberg, J.; Karl, T.; Turnipseed, A.; Apel, E. C.; Guenther, A. B.; Harley, P. C.; Smith, J. N.

    2009-12-01

    that are dominated by a hemiterpene, 2-methyl-3-butene-2-ol(MBO), and five monoterpene species. A comparison of observed and calculated OH reactivity shows that the calculated OH reactivity is about 50% less than the observed value. These measurements were carried out at the part of the BEACHON-SRM08 project.

  7. Processing of polyolefin blends in supercritical propane solution

    Science.gov (United States)

    Han, Suh Joon

    New polymer blending methods are developed and studied by processing polyolefins in supercritical propane in this research. Polypropylene and ethylene copolymers were dissolved in supercritical propane, and processed via various paths and reactions, i.e., RESS (rapid expansion of supercritical solution), ICSS (isobaric crystallization from supercritical solution), and thermoplastic vulcanizate (TPV) formation. Each process resulted in a unique morphology of polyolefin blends. The effect of polyolefin microstructure on the solution behavior in supercritical propane was investigated, and the relationship between the morphology of the polyolefin blends and processing paths in supercritical propane solutions was established. To understand the thermodynamic properties of polyolefins in bulk and solutions, the solubility parameter was estimated by measurement of the internal pressure from the experimental P-V-T data for polyolefins in the melt state. As the short chain branch content in the ethylene copolymers increased, the internal pressure decreased. The cloud-point pressures of binary polymer solutions in propane decreased as the extent of short chain branching increased in the ethylene copolymers. At the same degree of branching, the cloud-point pressure decreased slightly with increasing branch length. The cloud-point pressures of a ternary polymer solution in the pressure-temperature phase diagrams were higher than those of binary polymer solutions at the same composition (indicating poorer solubility). Microfibers and microparticles (10 ˜ 50 mum diameter) were precipitated from the RESS process while microcellular foams were obtained from the ICSS process. The phase domains of the ethylene-butene (EB) copolymer in the polypropylene from the RESS process were smaller for highly branched EB copolymer. The surface morphology of ethylene copolymers in the microcelluar foams was also changed by increasing the branch content from microparticles to a viscous layer. New

  8. Alexip: an Expert System Coupled with a Dynamic Simulator for the Supervision of the Alphabutol Process ALEXIP : système couplé à un simulateur dynamique pour la supervision du procédé Alphabutol

    Directory of Open Access Journals (Sweden)

    Cauvin S.

    2006-11-01

    Full Text Available ALEXIP (ALphabutol EXpert IFP is a knowledge-based system designed to improve the operation of the Alphabutol petrochemical process (IFP process which produces 1-butene by dimerizing ethylene by helping the operators in their process control tasks in running industrial units. Coupled with a dynamic simulator, this system assesses the situation of the process at any time and determines the measures to be taken to maintain it or to bring it into a state of optimal operation. The structure developed is generic. The knowledge is stored in the form of facts easily read by the experts and processed by general rules written in second-order logic using the Genesia 2 software. It accordingly helps to accommodate new knowledge easily, and can be adapted to other processes. ALEXIP (ALphabutol Expert IFP est un système à base de connaissances dont le but est d'améliorer l'exploitation du procédé pétrochimique Alphabutol (procédé IFP qui produit du butène-1 par dimérisation de l'éthylène en aidant les opérateurs dans leurs tâches de conduite des unités industrielles. Couplé à un simulateur dynamique, ce système analyse l'état dans lequel se trouve le procédé à un instant donné et détermine les actions à entreprendre pour le maintenir ou le ramener dans un état de fonctionnement optimal. La structure élaborée est générique ; la connaissance est stockée sous forme de faits lisibles facilement par les experts et traités par des règles générales écrites en logique d'ordre 2 à l'aide du logiciel Génésia 2. Elle permet donc d'accueillir facilement de nouvelles connaissances et peut être adaptée à d'autres procédés.

  9. [Role of surface-generated gas-phase radicals in heterogeneous catalysis] Final Technical Report, January 1, 1994 - December 31, 2001; FINAL

    International Nuclear Information System (INIS)

    A major theme in this research has been the role of surface-generated gas-phase radicals in heterogeneous catalysis, with emphasis on methyl radicals formed from methane. The activation of methane is of particular interest because of its abundance as a hydrocarbon resource. Previous studies on methyl radicals showed that they are an intermediate in the oxidative coupling of methane to form ethane and subsequently ethylene. More recent research on methyl radicals has focused on their coupling with allyl radicals, derived from propylene, to produce 1-butene and the methylation of ethylene to form propylene. As an extension of the work on methyl radicals, it has been shown that their reaction with vanadium oxide yields surface methoxide ions which either decompose to formaldehyde or react with water to form methanol. The surface and gas phase chemistry of methyl radicals also provided a link to the removal of NOx. In an attempt to explore the validity of a mechanism put forth by Vannice and co-workers, it was shown under this DOE grant that over basic metal oxides methyl radicals indeed react with gas phase NO to form nitrosomethane which is believed to be an intermediate in the selective catalytic reduction (SCR). Over one of these basic oxide catalysts (BaO/MgO), the decomposition of N2O was studied to determine the role of peroxide ions as an intermediate. Hydroxyl radicals also may be formed on surfaces and enter the gas phase where they can promote chain branching reactions during hydrocarbon oxidation. The formation of these radicals during the reaction of water with molecular oxygen over basic oxide catalysts has been studied in detail. A kinetic model provided evidence that these surface generated radicals may play a role in catalytic combustion. Since the hydroxyl radicals may undergo secondary reactions with a surface, this aspect of their chemistry was also explored. In contrast to the low probability of methyl radicals reacting with metal oxide surfaces

  10. Terpenoid emissions from fully grown east Siberian Larix cajanderi trees

    Directory of Open Access Journals (Sweden)

    M. K. Kajos

    2013-07-01

    Full Text Available While emissions of many biogenic volatile organic compounds (BVOCs, such as terpenoids, have been studied quite intensively in North American and Scandinavian boreal forests, the vast Siberian boreal forests have remained largely unexplored by experimental emission studies. In this study the shoot-scale terpenoid emission rates from two mature Larix cajanderi trees growing in their natural habitat in eastern Siberia were measured at the Spasskaya Pad flux measurement site (62°15´18.4" N, 129°37´07.9" E located on the western bank of the Lena river. The measurements were conducted during three campaigns: 3–24 June, 8–26 July, and 14–30 August, in the summer of 2009. A dynamic flow-through enclosure technique was applied for adsorbent sampling, and the samples were analysed offline with a gas chromatograph. Between 29 and 45 samples were taken from each shoot during all three campaigns. Seven different monoterpenes, six different sesquiterpenes, linalool isoprene, and 2-methyl-3-buten-2-ol (MBO were identified. The monthly median value of the total terpenoid emissions varied between 0.006 and 10.6 μg gdw−1 h−1. The emissions were dominated by monoterpenes, which constituted between 61 and 92% of the total emissions. About half of the monoterpene emissions were comprised of Δ 3-carene; α- and β-pinene had significant emissions as well. Linalool emissions were also substantial, comprising 3–37% of the total emissions, especially in June. Sesquiterpenes accounted for less than 3% and isoprene less than 1% of the total emissions. Based on the measured emission rates, the relative atmospheric concentration of each compound was estimated. Monoterpenes were the species with the highest relative concentration, while linalool and sesquiterpenes had a notably smaller contribution to the estimated atmospheric concentration than to the emission rates. A temperature-dependent pool algorithm with a constant β (0.09 °C−1 for monoterpenes

  11. Mixing Up the Pieces of the Desferrioxamine B Jigsaw Defines the Biosynthetic Sequence Catalyzed by DesD.

    Science.gov (United States)

    Telfer, Thomas J; Gotsbacher, Michael P; Soe, Cho Zin; Codd, Rachel

    2016-05-20

    Late-stage assembly of the trimeric linear siderophore desferrioxamine B (DFOB) native to Streptomyces pilosus involves two DesD-catalyzed condensation reactions between one N-acetyl-N-hydroxy-1,5-diaminopentane (AHDP) unit and two N-succinyl-N-hydroxy-1,5-diaminopentane (SHDP) units. AHDP and SHDP are products of DesBC-catalyzed reactions of the native diamine substrate 1,5-diaminopentane (DP). The sequence of DesD-catalyzed DFOB biosynthesis was delineated by analyzing the distribution of DFOB analogues and dimeric precursors assembled by S. pilosus in medium containing 1,4-diamino-2(E)-butene (E-DBE). Seven unsaturated DFOB analogues were produced that were partially resolved by liquid chromatography (LC). Mass spectrometry (MS) measurements reported on the combination of E-DBE- and DP-derived substrates in each trimer (uDFOA1 series, 1:2; uDFOA2 series, 2:1; uDFOA3, 3:0). MS/MS fragmentation patterns reported on the absolute position of the substrate derivative at the N-acetylated terminus, the internal region, or the amine terminus of the trimer. The uDFOA1 and uDFOA2 series each comprised three constitutional isomers (binary notation (DP-derived substrate "0," E-DBE-derived substrate "1"); direction, N-acetylated-internal-amine): uDFOA1[001], uDFOA1[010], uDFOA1[100]; and uDFOA2[011], uDFOA2[110], and uDFOA2[101]. E-DBE completely replaced DP in uDFOA3[111]. Relative concentrations of the uDFOA1 series were uDFOA1[001] ≫ uDFOA1[100] > uDFOA1[010] and of the uDFOA2 series, uDFOA2[101] > uDFOA2[011] ≫ uDFOA2[110]. Dimeric compounds assembled from one N-acetylated and one N-succinylated substrate derivative were detected as trimer precursors: dDFX[00-] ≫ udDFX[10-] > udDFX[01-] (d = dimer, vacant position "-"). Relative concentrations of all species were consistent with the biosynthetic sequence: (i) SHDP activation, (ii) condensation with AHDP to form AHDP-SHDP, (iii) SHDP activation, and (iv) condensation with AHDP-SHDP to form DFOB. PMID:27004785

  12. Redução da hidrofilicidade de filmes biodegradáveis à base de amido por meio de polimerização por plasma Reduction of hydrophilicity of biodegradable starch-based films by plasma polymerization

    Directory of Open Access Journals (Sweden)

    Rossana M. S. M. Thiré

    2004-03-01

    Full Text Available Devido ao baixo custo de produção e excelente biodegradabilidade, o amido constitui-se em matéria-prima promissora para a produção de plásticos biodegradáveis. No entanto, a grande hidrofilicidade dos filmes à base de amido representa uma séria limitação tecnológica à sua comercialização, uma vez que as propriedades dos filmes são afetadas pela variação da umidade relativa do ar durante a sua estocagem ou o seu uso. Neste trabalho, filmes de amido termoplástico foram recobertos com uma fina camada protetora polimérica gerada por intermédio da tecnologia de plasma frio. 1-Buteno e 1,3-butadieno foram utilizados como monômeros para a polimerização por plasma. Os filmes recobertos apresentaram uma redução de até 80% na absorção de água e aumento do ângulo de contato em relação à água. Estes resultados indicaram uma redução significativa na natureza hidrofílica do material à base de amido após o recobrimento.Due to low cost and excellent biodegradability, the use of starch as a raw material for bioplastic production is growing in interest. However, the properties of starch-based materials are affected by relative humidity during their use and storage due to their hydrophilic character. In this work, thermoplastic cornstarch films were coated by cold plasma technology with a protective thin layer in order to reduce water sensitivity. 1-Butene and 1,3-butadiene were used as monomers for plasma polymerization. Coated films presented a reduction of water absorption up to 80% an increase in contact angle related to water. These results indicated that the coating process reduced significantly the hydrophilic nature of the starch-based materials.

  13. OH Radical Reaction Rate Coefficients, Infrared Spectrum, and Global Warming Potential of (CF3)2CFCH═CHF (HFO-1438ezy(E)).

    Science.gov (United States)

    Papadimitriou, Vassileios C; Burkholder, James B

    2016-08-25

    Rate coefficients, k(T), for the OH radical + (E)-(CF3)2CFCH═CHF ((E)-1,3,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene, HFO-1438ezy(E)) gas-phase reaction were measured using pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) between 214 and 380 K and 50 and 450 Torr (He or N2 bath gas) and with a relative rate method at 296 K between 100 and 400 Torr (synthetic air). Over the range of pressures included in this study, no pressure dependence in k(T) was observed. k(296 K) obtained using the two techniques agreed to within ∼3% with (3.26 ± 0.26) × 10(-13) cm(3) molecule(-1) s(-1) (2σ absolute uncertainty) obtained using the PLP-LIF technique. k(T) displayed non-Arrhenius behavior that is reproduced by (7.34 ± 0.30) × 10(-19)T(2) exp[(481 ± 10)/T) cm(3) molecule(-1) s(-1). With respect to OH reactive loss, the atmospheric lifetime of HFO-1438ezy(E) is estimated to be ∼36 days and HFO-1438ezy(E) is considered a very short-lived substance (VSLS) (the actual lifetime will depend on the time and location of the HFO-1438ezy(E) emission). On the basis of the HFO-1438ezy(E) infrared absorption spectrum measured in this work and its estimated lifetime, a radiative efficiency of 0.306 W m(-2) ppb(-1) (well-mixed gas) was calculated and its 100-year time-horizon global warming potential, GWP100, was estimated to be 8.6. CF3CFO, HC(O)F, and CF2O were identified using infrared spectroscopy as stable end products in the oxidation of HFO-1438ezy(E) in the presence of O2. Two additional fluorinated products were observed and theoretical calculations of the infrared spectra of likely degradation products are presented. The photochemical ozone creation potential of HFO-1438ezy(E) was estimated to be ∼2.15.

  14. OH Radical Reaction Rate Coefficients, Infrared Spectrum, and Global Warming Potential of (CF3)2CFCH═CHF (HFO-1438ezy(E)).

    Science.gov (United States)

    Papadimitriou, Vassileios C; Burkholder, James B

    2016-08-25

    Rate coefficients, k(T), for the OH radical + (E)-(CF3)2CFCH═CHF ((E)-1,3,4,4,4-pentafluoro-3-(trifluoromethyl)-1-butene, HFO-1438ezy(E)) gas-phase reaction were measured using pulsed laser photolysis-laser-induced fluorescence (PLP-LIF) between 214 and 380 K and 50 and 450 Torr (He or N2 bath gas) and with a relative rate method at 296 K between 100 and 400 Torr (synthetic air). Over the range of pressures included in this study, no pressure dependence in k(T) was observed. k(296 K) obtained using the two techniques agreed to within ∼3% with (3.26 ± 0.26) × 10(-13) cm(3) molecule(-1) s(-1) (2σ absolute uncertainty) obtained using the PLP-LIF technique. k(T) displayed non-Arrhenius behavior that is reproduced by (7.34 ± 0.30) × 10(-19)T(2) exp[(481 ± 10)/T) cm(3) molecule(-1) s(-1). With respect to OH reactive loss, the atmospheric lifetime of HFO-1438ezy(E) is estimated to be ∼36 days and HFO-1438ezy(E) is considered a very short-lived substance (VSLS) (the actual lifetime will depend on the time and location of the HFO-1438ezy(E) emission). On the basis of the HFO-1438ezy(E) infrared absorption spectrum measured in this work and its estimated lifetime, a radiative efficiency of 0.306 W m(-2) ppb(-1) (well-mixed gas) was calculated and its 100-year time-horizon global warming potential, GWP100, was estimated to be 8.6. CF3CFO, HC(O)F, and CF2O were identified using infrared spectroscopy as stable end products in the oxidation of HFO-1438ezy(E) in the presence of O2. Two additional fluorinated products were observed and theoretical calculations of the infrared spectra of likely degradation products are presented. The photochemical ozone creation potential of HFO-1438ezy(E) was estimated to be ∼2.15. PMID:27482844

  15. Análise de copolímeros de etileno alfa-olefinas por meio de técnicas de fracionamento Ethylene copolymers analysis by fractionation techniques

    Directory of Open Access Journals (Sweden)

    Fernanda F. N. Escher

    2000-12-01

    Full Text Available Este trabalho apresenta a avaliação da heterogeneidade de resinas comerciais de copolímeros de etileno-1-buteno, produzidas por diferentes processos com catalisadores Ziegler-Natta e de resinas de copolímeros de etileno-1-hexeno sintetizadas em laboratório com catalisadores metalocênicos suportados e em solução. Para fazer a avaliação da heterogeneidade foram empregadas técnicas de fracionamento por extração com diferentes solventes e temperaturas e fracionamento térmico por DSC. As frações obtidas foram caracterizadas por 13C-NMR, FTIR, SEC e DSC. Como esperado, foi confirmada uma maior heterogeneidade das resinas sintetizadas com catalisador Ziegler-Natta quando comparadas às resinas metalocênicas. A resina obtida com catalisador Ziegler-Natta, produzida pelo processo Union Carbide (UCC, apresenta uma incorporação mais homogênea de comonômero do que o processo Spherilene. A resina obtida com catalisador metalocênico homogêneo permite maior incorporação de comonômero resultando em uma maior heterogeneidade no tamanho das cadeias comparada com a obtida com catalisador metalocênico suportado.Samples of ethylene 1-butene copolymer, produced in laboratory by different processes using Ziegler-Natta catalysts, ethylene-1-hexene and metallocene catalysts, were fractionated according to molecular size by direct extraction by different solvents and at different temperatures. These samples were also fractionated by differences on crystallinity using a DSC calorimeter. The obtained fractions were characterized by 13C-NMR , FTIR, GPC and DSC. The polyethylene copolymers produced by Ziegler-Natta catalyst were found more heterogeneous when compared with the one produced by metallocene catalysts. The commercial resin produced by UCC process with Ziegler-Natta catalysts showed a more homogeneous incorporation of comonomer compared with the one obtained by the Spherilene process. The supported metallocene catalyst gave a more

  16. Molecular order, miscibility, and rheology of molten polyethylenes

    Science.gov (United States)

    Hussein, Ibnelwaleed Ali

    of LLDPE and LDPE is discussed. Partial miscibility is observed in blends mixed at a temperature below 208°C, whereas blends mixed above that temperature were almost immiscible. Increasing the branch length of the LLDPE from butene to octene increased miscibility slightly. Literature reporting polyethylene melt behavior is critically reviewed over the last four decades and found to contain many anomalies of molecular order and structural transformations. The scientific community and the polyethylene processing industry need to investigate the implications of these findings.

  17. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2012-10-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK+MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK+MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the

  18. Comparison of different real time VOC measurement techniques in a ponderosa pine forest

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2013-03-01

    Full Text Available Volatile organic compound (VOC mixing ratios measured by five independent instruments are compared at a forested site dominated by ponderosa pine (Pinus Ponderosa during the BEACHON-ROCS field study in summer 2010. The instruments included a Proton Transfer Reaction Time of Flight Mass Spectrometer (PTR-TOF-MS, a Proton Transfer Reaction Quadrupole Mass Spectrometer (PTR-MS, a Fast Online Gas-Chromatograph coupled to a Mass Spectrometer (GC/MS; TOGA, a Thermal Dissociation Chemical Ionization Mass Spectrometer (PAN-CIMS and a Fiber Laser-Induced Fluorescence Instrument (FILIF. The species discussed in this comparison include the most important biogenic VOCs and a selected suite of oxygenated VOCs that are thought to dominate the VOC reactivity at this particular site as well as typical anthropogenic VOCs that showed low mixing ratios at this site. Good agreement was observed for methanol, the sum of the oxygenated hemiterpene 2-methyl-3-buten-2-ol (MBO and the hemiterpene isoprene, acetaldehyde, the sum of acetone and propanal, benzene and the sum of methyl ethyl ketone (MEK and butanal. Measurements of the above VOCs conducted by different instruments agree within 20%. The ability to differentiate the presence of toluene and cymene by PTR-TOF-MS is tested based on a comparison with GC-MS measurements, suggesting a study-average relative contribution of 74% for toluene and 26% for cymene. Similarly, 2-hydroxy-2-methylpropanal (HMPR is found to interfere with the sum of methyl vinyl ketone and methacrolein (MVK + MAC using PTR-(TOF-MS at this site. A study-average relative contribution of 85% for MVK + MAC and 15% for HMPR was determined. The sum of monoterpenes measured by PTR-MS and PTR-TOF-MS was generally 20–25% higher than the sum of speciated monoterpenes measured by TOGA, which included α-pinene, β-pinene, camphene, carene, myrcene, limonene, cineole as well as other terpenes. However, this difference is consistent throughout the study

  19. Studies of the Atmospheric Chemsitry of Energy-Related Volatile Organic Compounds and of their Atmospheric Reaction Products

    Energy Technology Data Exchange (ETDEWEB)

    Roger Atkinson; Janet Arey

    2007-04-14

    The focus of this contract was to investigate selected aspects of the atmospheric chemistry of volatile organic compounds (VOCs) emitted into the atmosphere from energy-related sources as well as from biogenic sources. The classes of VOCs studied were polycyclic aromatic hydrocarbons (PAHs) and nitro-PAHs, the biogenic VOCs isoprene, 2-methyl-3-buten-2-ol and cis-3-hexen-1-ol, alkenes (including alkenes emitted from vegetation) and their oxygenated atmospheric reaction products, and a series of oxygenated carbonyl and hydroxycarbonyl compounds formed as atmospheric reaction products of aromatic hydrocarbons and other VOCs. Large volume reaction chambers were used to investigate the kinetics and/or products of photolysis and of the gas-phase reactions of these organic compounds with hydroxyl (OH) radicals, nitrate (NO3) radicals, and ozone (O3), using an array of analytical instrumentation to analyze the reactants and products (including gas chromatography, in situ Fourier transform infrared spectroscopy, and direct air sampling atmospheric pressure ionization tandem mass spectrometry). The following studies were carried out. The photolysis rates of 1- and 2-nitronaphthalene and of eleven isomeric methylnitronaphthalenes were measured indoors using blacklamp irradiation and outdoors using natural sunlight. Rate constants were measured for the gas-phase reactions of OH radicals, Cl atoms and NO3 radicals with naphthalene, 1- and 2-methylnaphthalene, 1- and 2-ethylnaphthalene and the ten dimethylnaphthalene isomers. Rate constants were measured for the gas-phase reactions of OH radicals with four unsaturated carbonyls and with a series of hydroxyaldehydes formed as atmospheric reaction products of other VOCs, and for the gas-phase reactions of O3 with a series of cycloalkenes. Products of the gas-phase reactions of OH radicals and O3 with a series of biogenically emitted VOCs were identified and quantified. Ambient atmospheric measurements of the concentrations of a

  20. Temperature and light dependence of the VOC emissions of Scots pine

    Directory of Open Access Journals (Sweden)

    V. Tarvainen

    2004-10-01

    Full Text Available The volatile organic compound (VOC emission rates of Scots pine (Pinus sylvestris L. were measured from trees growing in a natural forest environment at two locations in Finland. The emission rate measurements were carried out using a dynamic flow through technique with samples collected on adsorbent tubes and analyzed using thermodesorption followed by a gas chromatograph with a mass-selective detector (GC-MS. The standard emission potentials (at 303.15 K and 1000 µmol photons m−2 s−1 were calculated for the measured compounds using nonlinear regression to fit the experimental data to temperature and light dependent emission algorithms.

    The observed total VOC emission rates varied between 21 and 874 ng/g(dw*h and 268 and 1670 ng/g(dw*h in southern and northern Finland, respectively. A clear seasonal cycle was detected with high emission rates in early spring, a decrease of the emissions in late spring and early summer, high emissions again in late summer, and a gradual decrease in autumn.

    The main emitted compounds were Δ3-carene (southern Finland and α- and β-pinene (northern Finland, with approximate relative contributions of 60–70% and 60–85% of the total observed monoterpene emission rates, respectively. Sesquiterpene (β-caryophyllene and 2-methyl-3-buten-2-ol (MBO emissions were initiated in early summer at both sites. The observed MBO emission rates were between 1 and 3.5% of the total monoterpene emission rates. The sesquiterpene emission rates varied between 2 and 5% of the total monoterpene emission rates in southern Finland, but were high (40% in northern Finland in spring.

    Most of the measured emission rates were found to be well described by the temperature dependent emission algorithm. The calculated standard emission potentials were high in spring and early summer, decreased somewhat in late summer, and were high again towards autumn. The experimental

  1. Emission characteristics of nonmethane hydrocarbons from private cars and taxis at different driving speeds in Hong Kong

    Science.gov (United States)

    Guo, H.; Zou, S. C.; Tsai, W. Y.; Chan, L. Y.; Blake, D. R.

    2011-05-01

    Vehicular emissions are the major sources of a number of air pollutants including nonmethane hydrocarbons (NMHCs) in urban area. The emission composition and emission factors of NMHCs from vehicles are currently lacking in Hong Kong. In this study, speciation and emission factors of NMHCs emitted from gasoline-fuelled private cars and liquefied petroleum gas (LPG)-fuelled taxis at different driving speeds were constructed using a chassis dynamometer. Large variations in the contributions of individual NMHC species to total emission were observed for different private cars at different driving speeds. The variations of individual NMHC emissions were relatively smaller for taxis due to their relatively homogeneous year of manufacture and mileages. Incomplete combustion products like ethane, ethene and propene were the major component of both types of vehicles, while unburned fuel component was also abundant in the exhausts of private cars and taxis (i.e. i-pentane and toluene for private car, and propane and butanes for taxi). Emission factors of major NMHCs emitted from private cars and taxis were estimated. High emission factors of ethane, n-butane, i/ n-pentanes, methylpentanes, trimethylpentanes, ethene, propene, i-butene, benzene, toluene and xylenes were found for private cars, whereas propane and i/ n-butanes had the highest values for taxis. By evaluating the effect of vehicular emissions on the ozone formation potential (OFP), it was found that the contributions of olefinic and aromatic hydrocarbons to OFP were higher than that from paraffinic hydrocarbons for private car, whereas the contributions of propane and i/ n-butanes were the highest for taxis. The total OFP value was higher at lower speeds (≤50 km h -1) for private cars while a minimum value at driving speed of 100 km h -1 was found for taxis. At the steady driving speeds, the total contribution of NMHCs emitted from LPG-fuelled taxis to the OFP was much lower than that from gasoline

  2. The effect of free radical inhibitor on the sensitized radiation crosslinking and thermal processing stabilization of polyurethane shape memory polymers

    International Nuclear Information System (INIS)

    The effects of free radical inhibitor on the electron beam crosslinking and thermal processing stabilization of novel radiation crosslinkable polyurethane shape memory polymers (SMPs) blended with acrylic radiation sensitizers have been determined. The SMPs in this study possess novel processing capabilities—that is, the ability to be melt processed into complex geometries as thermoplastics and crosslinked in a secondary step using electron beam irradiation. To increase susceptibility to radiation crosslinking, the radiation sensitizer pentaerythritol triacrylate (PETA) was solution blended with thermoplastic polyurethane SMPs made from 2-butene-1,4-diol and trimethylhexamethylene diisocyanate (TMHDI). Because the thermoplastic melt processing methods such as injection molding are often carried out at elevated temperatures, sensitizer thermal instability is a major processing concern. Free radical inhibitor can be added to provide thermal stabilization; however, inhibitor can also undesirably inhibit radiation crosslinking. In this study, we quantified both the thermal stabilization and radiation crosslinking inhibition effects of the inhibitor 1,4-benzoquinone (BQ) on polyurethane SMPs blended with PETA. Sol/gel analysis of irradiated samples showed that the inhibitor had little to no inverse effects on gel fraction at concentrations of 0–10,000 ppm, and dynamic mechanical analysis showed only a slight negative correlation between BQ composition and rubbery modulus. The 1,4-benzoquinone was also highly effective in thermally stabilizing the acrylic sensitizers. The polymer blends could be heated to 150 °C for up to 5 h or to 125 °C for up to 24 h if stabilized with 10,000 ppm BQ and could also be heated to 125 °C for up to 5 h if stabilized with 1000 ppm BQ without sensitizer reaction occurring. We believe this study provides significant insight into methods for manipulation of the competing mechanisms of radiation crosslinking and thermal stabilization of

  3. Case study on the utility of hepatic global gene expression profiling in the risk assessment of the carcinogen furan

    Energy Technology Data Exchange (ETDEWEB)

    Jackson, Anna Francina, E-mail: Francina.Jackson@hc-sc.gc.ca [Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9 (Canada); Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6 (Canada); Williams, Andrew, E-mail: Andrew.Williams@hc-sc.gc.ca [Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9 (Canada); Recio, Leslie, E-mail: lrecio@ils-inc.com [ILS, Inc., P.O. Box 13501, Research Triangle Park, NC 27709 (United States); Waters, Michael D., E-mail: mwaters@ils-inc.com [ILS, Inc., P.O. Box 13501, Research Triangle Park, NC 27709 (United States); Lambert, Iain B., E-mail: Iain.Lambert@carleton.ca [Department of Biology, Carleton University, 1125 Colonel By Drive, Ottawa K1S 5B6 (Canada); Yauk, Carole L., E-mail: Carole.Yauk@hc-sc.gc.ca [Environmental Health Science and Research Bureau, Health Canada, Ottawa K1A 0K9 (Canada)

    2014-01-01

    Furan is a chemical hepatocarcinogen in mice and rats. Its previously postulated cancer mode of action (MOA) is chronic cytotoxicity followed by sustained regenerative proliferation; however, its molecular basis is unknown. To this end, we conducted toxicogenomic analysis of B3C6F1 mouse livers following three week exposures to non-carcinogenic (0, 1, 2 mg/kg bw) or carcinogenic (4 and 8 mg/kg bw) doses of furan. We saw enrichment for pathways responsible for cytotoxicity: stress-activated protein kinase (SAPK) and death receptor (DR5 and TNF-alpha) signaling, and proliferation: extracellular signal-regulated kinases (ERKs) and TNF-alpha. We also noted the involvement of NF-kappaB and c-Jun in response to furan, which are genes that are known to be required for liver regeneration. Furan metabolism by CYP2E1 produces cis-2-butene-1,4-dial (BDA), which is required for ensuing cytotoxicity and oxidative stress. NRF2 is a master regulator of gene expression during oxidative stress and we suggest that chronic NFR2 activity and chronic inflammation may represent critical transition events between the adaptive (regeneration) and adverse (cancer) outcomes. Another objective of this study was to demonstrate the applicability of toxicogenomics data in quantitative risk assessment. We modeled benchmark doses for our transcriptional data and previously published cancer data, and observed consistency between the two. Margin of exposure values for both transcriptional and cancer endpoints were also similar. In conclusion, using furan as a case study we have demonstrated the value of toxicogenomics data in elucidating dose-dependent MOA transitions and in quantitative risk assessment. - Highlights: • Global gene expression changes in furan-exposed mouse livers were analyzed. • A molecular mode of action for furan-induced hepatocarcinogenesis is proposed. • Key pathways include NRF2, SAPK, ERK and death receptor signaling. • Important roles for TNF-alpha, c-Jun, and NF

  4. Knowledge Based Catalyst Design by High Throughput Screening of Model Reactions and Statistical Modelling Conception de catalyseur par criblage à haut débit de réactions modèles et modélisation statistique

    Directory of Open Access Journals (Sweden)

    Morra G.

    2013-08-01

    Full Text Available Material design and synthesis are key steps in the development of catalysts. They are usually based on an empiric and/or theoretical approach. The recently developed high-throughput experimentation can accelerate optimisation of new catalytic formulations by systematic screening in a predefined study domain. This work aims at developing a QSAR (Quantitative Structure Activity Relationship method based on kinetic and mechanistic descriptors for metal and acid catalysis. Physico-chemicalfeatures of approximately sixty bimetallic catalysts have been measured according to their performance in two model reactions: xylene hydrogenation for catalysis on metallic sites and isomerisation of 3,3-dimethyl-l-butene for catalysis on acid sites. These descriptors were finally used to model the performances of around twenty catalysts for a more complex reaction: n-decane dehydrogenation. La définition et la préparation de matériaux sont des étapes clés dans le développement de catalyseurs. Celles-ci peuvent être effectuées de façon empirique et/ou à partir de bases théoriques. Par ailleurs, l’expérimentation à haut débit, technologie récente, permet d’accélérer l’optimisation de formulations catalytiques par exemple par criblage systématique d’un espace d’étude prédéfini. Cet article a pour objet de développer une méthode QSAR (Quantitative Structure Activity Relationship basée sur la recherche de descripteurs cinétiques et mécanistiques, dans le domaine de la catalyse acide et métallique supportée. Des caractéristiques physico-chimiques (descripteurs d’une soixantaine de catalyseurs bimétalliques ont été mesurées suivant leur performance dans deux réactions modèles : l’hydrogénation de ro-xylène pour rendre compte de la catalyse par le métal et l’isomérisation du diméthyl-3,3butène-1 pour la catalyse par les sites acides. Ces descripteurs ont été ensuite mis à profit pour modéliser les performances

  5. Pressure Effects on Product Channels of the Allyl Radical Reactions; C3H5+C3H5 and C3H5+CH3

    Science.gov (United States)

    Halpern, J. B.; N'Doumi, M.; Fahr, A.

    2011-12-01

    Relatively large hydrocarbon molecules (C4, C6 and larger) have been detected in several planetary environments. The mechanism for the formation of such large molecular species and detailed mechanism for their potential destruction are not well understood and are of considerable current interest. Previously we have studied the kinetics and product channels of small unsaturated hydrocarbon radical (C2 and C3s) reactions relevant to planetary atmospheric modeling. Reactions of C2 radicals (such as vinyl, H2CCH and ethynyl C2H) and C3 radicals (such as propargyl, HCCCH2) can affect the abundances of a large number of stable observable C3, C4, C5, C6 and larger molecules, including linear, aromatic and even poly aromatic molecules. Pressure-dependent product yields have been determined experimentally for the self- and cross-radical reactions performed at 298 K and at pressures between ~4 Torr (0.5 kPa) and 760 Torr (101 kPa). Final reaction products were quantitatively determined using a gas chromatograph with mass spectrometry/flame ionization detection (GC/MS/FID). In some cases complementary computational studies extended the pressure and temperature range of the experiments and provided valuable information on the complex reaction mechanisms. Theses studies provide a systematic framework so that important energetic and structural parameters for radical-radical reactions can be assessed. Here we report recent results for the allyl radical reactions H2CCCH3+ H2CCCH3 and H2CCCH3+CH3. For the allyl radical self-reaction, at high pressures the "head -to-head", combination channel forming 1,5-hexadiene is dominant with a combination/disproportionation = 1,5-hexadiene/propyne ratio of about 24 at 500 Torr (67 kPa, T=298K). At low pressures the ratio is substantially reduced to about 1.2 (at 0.3 kPa) and other major products are observed including allene, propene, 1-butene and propyne.

  6. Volatile organic compound speciation above and within a Douglas fir forest

    Science.gov (United States)

    Copeland, Nichola; Cape, J. Neil; Nemitz, Eiko; Heal, Mathew R.

    2014-09-01

    Mixing ratios and fluxes of volatile organic compounds (VOCs) were measured by PTR-MS (and GC-MS) and virtual disjunct eddy covariance during a three-week field campaign in summer 2009 within and above a Douglas fir (Pseudotsuga menziesii) forest in Speulderbos, the Netherlands. Measurements included the first non-terpenoid species fluxes and mixing ratios for Douglas fir canopy. Above-canopy emissions of monoterpenes were comparable to previous studies of P. menziesii, with estimated standard emission factors for the first and second halves of the campaign of 0.8 ± 0.4 and 0.8 ± 0.3 μg gdw-1 h-1, and temperature coefficients of 0.19 ± 0.06 and 0.08 ± 0.05 °C-1, respectively. Estimated isoprene standard emission factors for the two halves of the campaign were 0.09 ± 0.12 and 0.16 ± 0.18 μg gdw-1 h-1. Fluxes of several non-terpenoid VOCs were significant, with maximum fluxes greater than has been measured for other coniferous species. α-Pinene was the dominant monoterpene within and above the canopy. Within-canopy mixing ratios of individual species were generally greatest in early evening consistent with reduced vertical mixing and continued temperature-dependent emissions. Acetaldehyde, acetone and monoterpenes had elevated mixing ratios toward the bottom of the canopy (5-10 m) with assumed contribution from the large quantities of forest-floor leaf litter. MBO (2-methyl-3-buten-2-ol) and estragole had peak mixing ratios at the top of the canopy and are known to have coniferous sources. MVK + MACR (methyl vinyl ketone and methacrolein) also had highest mixing ratios at the top of the canopy consistent with formation from in-canopy oxidation of isoprene. The work highlights the importance of quantifying a wider variety of VOCs from biogenic sources than isoprene and monoterpenes.

  7. The Field Control Efficiency of Five Types of Insecticides Against Grassland Locust%五种杀虫剂对大庆草原蝗虫的田间防治效果

    Institute of Scientific and Technical Information of China (English)

    杨志强; 杨苏宁; 魏金会; 徐维东; 金永玲

    2014-01-01

    In order to screen out the better insecticide against grassland locust in Daqing ,the efficiency of Avi Su Yunjun ,Azadirachtin ,Butene fipronil EC ,Fenvalerate and Avermectin against locust were compared by hanging method in Daqing .The results showed that 3 days after medieation ,the control efficiencies of Avi Su Yunjun and Azadirachtin were 56 .0% and 60 .0% ,and other insecticides were above 76 .0% .After 12 days for medica-tion ,the efficiency of Avi Su Yunjun reached 82 .9% ,other four insecticides attained 100 .0% .It illustrated that the efficiency of chemical insecticides was quick ,the efficiency of biological insecticides was slow ,suitable insec-ticides should be selected on the basis of situation to control grassland locusts .%为筛选出防效较好的杀虫剂用于大庆地区蝗虫的防治,采用笼罩式方法,应用印楝素乳油、阿维菌素、丁烯氟虫腈乳油、氰戊菊酯和阿维·苏云菌共5种杀虫剂对大庆地区草原蝗虫进行了田间药效对比试验。结果表明:药后3d,阿维·苏云菌和印楝素防效为56.0%和60.0%,其余防治效果均高于76.0%。药后12d,阿维·苏云菌防效达到82.9%,其余4种杀虫剂均达到100.0%。说明化学杀虫剂作用效果迅速,生物杀虫剂作用效果缓慢,应根据蝗虫的发生情况选择适宜的药剂进行防治。

  8. Undisturbed and disturbed above canopy ponderosa pine emissions: PTR-TOF-MS measurements and MEGAN 2.1 model results

    Directory of Open Access Journals (Sweden)

    L. Kaser

    2013-06-01

    Full Text Available We present the first eddy covariance flux measurements of volatile organic compounds (VOCs using a proton-transfer-reaction time-of-flight mass-spectrometer (PTR-TOF-MS above a ponderosa pine forest in Colorado, USA. The high mass resolution of the PTR-TOF-MS enabled the identification of chemical sum formulas. During a 30 day measurement period in August and September 2010, 649 different ion mass peaks were detected in the ambient air mass spectrum (including primary ions and mass calibration compounds. Eddy covariance with the vertical wind speed was calculated for all ion mass peaks. On a typical day, 17 ion mass peaks including protonated parent compounds, their fragments and isotopes as well as VOC-H+-water clusters showed a significant flux with daytime average emissions above a reliable flux threshold of 0.1 mg compound m−2 h−1. These ion mass peaks could be assigned to seven compound classes. The main flux contributions during daytime (10:00–18:00 LT are attributed to the sum of 2-methyl-3-buten-2-ol (MBO and isoprene (50%, methanol (12%, the sum of acetic acid and glycolaldehyde (10% and the sum of monoterpenes (10%. The total MBO + isoprene flux was composed of 10% isoprene and 90% MBO. There was good agreement between the light and temperature dependency of the sum of MBO and isoprene observed for this work and those of earlier studies. The above canopy flux measurements of the sum of MBO and isoprene and the sum of monoterpenes were compared to emissions calculated using the Model of Emissions of Gases and Aerosols from Nature (MEGAN 2.1. The best agreement between MEGAN 2.1 and measurements was reached using emission factors determined from site specific leaf cuvette measurements. While the modelled and measured MBO + isoprene fluxes agree well the emissions of the sum of monoterpenes is underestimated by MEGAN 2.1. This is expected as some factors impacting monoterpene emissions, such as physical damage of needles and

  9. STRUCTURAL CHARACTERIZATION OF POLYETHYLENES BY DSC ANALYSIS AFTER CRYSTALLIZATION SEGREGATION

    Institute of Scientific and Technical Information of China (English)

    Yu Ma; Mao Xu

    2000-01-01

    The molecular structure of polyethylene (PE) samples with various comonomers including propylene, 1-butene and 1-hexene was investigated by DSC and 13C-NMR techniques. The density of the samples varies from 0.948 g/cm3 to 0.917 g/cm3, and the molecular weight determined by the GPC method is in the range of 1~2 × 105. The branch point content of the samples was determined by 13C-NMR measurements and was found to be less than 20 per 1000 C atoms along the main chain. Crystallization segregation DSC technique (CSDSC) was used to characterize the branch point distribution or the segment length distribution of PEs. The crystallization segregation was performed in a successive annealing process at decreasing temperatures. The interval of two successive annealing temperatures was 6 K, and the time length of each annealing step was 2.5 h. The CSDSC results clearly indicate that all the PE samples used, including some metallocene PEs,more or less exhibit their non-uniformity in segment length distribution, and bimodal or multimodal CSDSC curves were usually observed. For quantitative characterization of the CSDSC curves and the segment length distribution two parameters,the average melting point, TmAV, and the root-mean-square deviation of melting temperature, (ATm2AV)1/2, were proposed.TmAV is corresponding to the average segment length due to branching and (ATm2AV)1/2 gives information about the width of the segment length distribution. Experimental results show that both the degree of average melting temperature depression and the width of the distribution seem to increase with increasing the branching content and are dependent on the type of comonomers. Very good reproducibility and additivity of the CSDSC method were evidenced experimentally. It was concluded that the CSDSC technique is a sensitive and convenient method for characterizing the segment length distribution of branched polyethylenes and will be of great interest in structure-property relationship

  10. 对(艹孟)烷-3,8-二醇的合成与应用研究进展%Research Progress on Synthesis and Application of p-Menthane-3,8-diol

    Institute of Scientific and Technical Information of China (English)

    何丽芝; 赵振东; 毕良武; 王鹏

    2012-01-01

    对(艹孟)烷-3,8-二醇是一种具有生物活性的化合物,主要来源于柠檬桉精油,可直接用于香水、杀虫剂和药品等.通常采用化学和生物化学的方法合成对(艹孟)烷-3,8-二醇,以替代从柠檬桉叶油分离得到的天然产品.以香茅醛为原料通过Prins环缩合和水解,或者通过Solanum aviculare悬浮培养方式进行生物转化得到对(艹孟)烷-3,8-二醇;通过薄荷醇的氧化,或者以2-丁烯醛为原料与甲基锂、NaClO2等试剂经过较长步骤也可合成对(艹孟)烷-3,8-二醇.对(艹孟)烷-3,8-二醇可应用于制造驱虫剂、凉味剂、药物或者化妆品的添加剂以及海水防护涂料添加剂等.%p-Menthane-3,8-diol (PMD) is a bioactive compound, which is first found in essential oil of leaves of Eucalyptus citriodora and often used as an active composition for perfume, insecticide, and medicine. It is usually synthesized by chemical or biological approaches instead of the direct isolation from the E. citriodora oil. PMD can be synthesized from citronellal through a prins reaction and a hydration,or be transformed from citronellal through a Solarium avwulare suspension culture. It can also be produced from menthol with an oxidation,or synthesized from 2-butenal by a long step reactions with reagents such as MeIi,NaClO2,etc.PMD can be used as repellent,coolant,pharmaceutical,cosmetics,and coatings.

  11. Synthesis of X-Ray Sensitive Polymers and Their Applications as Resists

    Science.gov (United States)

    Davies, Jack Dean

    Aliphatic polycarbonates were synthesized by condensation of the bischloroformate of 2,2,4,4-tetramethyl-1,3-cyclobutanediol with cyclic aliphatic diols. Polycarbonates that lacked flexible methylene units in the backbone processed T _{rm g} > 139 ^circC. Copolycarbonates acted as resists when combined with cobalt(III)-am(m)ine tetraphenylborate complexes which act as photointiators, with tetraphenylborate serving as counter anion. The photoinitiator liberates either ammonia or ethylene diamine base upon UV exposure and the polycarbonate backbone is subject to nucleophilic attack at the carbonyl linkage by the base. Image tone was dependent on the base used. Amine complexes, Co(NH _3)_6^{3+} effected a positive tone due to ammonia induced main chain degradation at the carbonate linkage. Cobalt ethylenediamine complex, Co(en)_3^{3+} , en is ethylenediamine, effected a negative tone. The released ethylenediamine acted as a tetrafunctional crosslinking agent forming carbamate linkages. Resolution studies determined linewidths to 20 mum. The amine complex, under low intensity UV radiation, >0.35 mW/cm^2, and elevated temperatures, >40^circC, promoted vapor developed positive tone images in the resists layer. 1-Butene, 2-methyl-1-pentene, cyclohexene, and norbornene were copolymerized with sulfur dioxide. Thermal characterization revealed that these copolymers possess low T_{rm g}, i.e., 800 mJ/cm ^2. Features to 0.4muM were obtained in this manner using a test mask. Novel polysulfones were prepared by the polymerization of SO_2 with conjugated dienes. Polymerizations were perfonned at -78^circ C in nitropropane as solvent using t-butyl hydroperoxide as initiator. The T_{rm g} of these polymers are >70 ^circC with similar degradation transitions seen for the poly (olefin sulfone) copolymers. These polymers are soluble in a common solvent, nitromethane. Poly(hexadiene -1,3 sulfone) acted as a positive tone resist when exposed to synchrotron radiation and developed in

  12. Complex Hydrocarbon Chemistry in Interstellar and Solar System Ices Revealed: A Combined Infrared Spectroscopy and Reflectron Time-of-flight Mass Spectrometry Analysis of Ethane (C2H6) and D6-Ethane (C2D6) Ices Exposed to Ionizing Radiation

    Science.gov (United States)

    Abplanalp, Matthew J.; Kaiser, Ralf I.

    2016-08-01

    The irradiation of pure ethane (C2H6/C2D6) ices at 5.5 K, under ultrahigh vacuum conditions was conducted to investigate the formation of complex hydrocarbons via interaction with energetic electrons simulating the secondary electrons produced in the track of galactic cosmic rays. The chemical modifications of the ices were monitored in situ using Fourier transform infrared spectroscopy (FTIR) and during temperature-programmed desorption via mass spectrometry exploiting a quadrupole mass spectrometer with electron impact ionization (EI-QMS) as well as a reflectron time-of-flight mass spectrometer coupled to a photoionization source (PI-ReTOF-MS). FTIR confirmed previous ethane studies by detecting six molecules: methane (CH4), acetylene (C2H2), ethylene (C2H4), the ethyl radical (C2H5), 1-butene (C4H8), and n-butane (C4H10). However, the TPD phase, along with EI-QMS, and most importantly, PI-ReTOF-MS, revealed the formation of at least 23 hydrocarbons, many for the first time in ethane ice, which can be arranged in four groups with an increasing carbon-to-hydrogen ratio: C n H2n+2 (n = 3, 4, 6, 8, 10), C n H2n (n = 3-10), {{{C}}}n{{{H}}}2n-2 (n = 3-10), and {{{C}}}n{{{H}}}2n-4 (n = 4-6). The processing of simple ethane ices is relevant to the hydrocarbon chemistry in the interstellar medium, as ethane has been shown to be a major product of methane, as well as in the outer solar system. These data reveal that the processing of ethane ices can synthesize several key hydrocarbons such as C3H4 and C4H6 isomers, which ha­ve been found to synthesize polycyclic aromatic hydrocarbons like indene (C9H8) and naphtha­lene (C10H8) in the ISM and in hydrocarbon-rich atmospheres of planets and their moons such as Titan.

  13. Chain and Ion Dynamics in Ionomer Melts

    Science.gov (United States)

    Register, Richard A.

    2003-03-01

    Ionomers contain a minor quantity of covalently-bound ionic sites, such as carboxylic or sulfonic acid salts, typically distributed randomly along the polymer backbone. Associations between these ionic groups greatly increase the melt viscosity and elasticity through the formation of a reversible network, where the ionic crosslinks gradually relax by a ``hopping" of ionic groups between aggregates. Because terminal relaxation of the chain requires an accumulation of many hops, the time scales for ion and chain motion differ by several orders of magnitude, so we employ mechanical rheometry to probe chain motion, and gauge ion motion through cation diffusion, by annealing for a preset interval and measuring the cation concentration profile through electron probe microanalysis or electron spin resonance spectroscopy. We have investigated both ethylene-methacrylic acid (E/MAA) ionomers, with a broad molecular weight distribution and substantial long-chain branching, as well as new linear-chain ionomers of narrow distribution based on lightly-sulfonated styrene-ethylene-butene (SSEB) terpolymers. Our E/MAA results support the ion-hopping mechanism, with similarly-large activation energies for terminal relaxation and cation diffusion. The choice of neutralizing metal cation has only a modest effect on the dynamics, though the terminal time increases exponentially with neutralization level. Unneutralized acid groups can accelerate the ion-hopping process by "plasticizing" the ionic aggregates. The model SSEB ionomers, which are noncrystallizable and have a low Tg, permit measurements over a much wider range of effective frequencies and are found to deviate substantially from time-temperature superposition, because the outermost portions of the polymer chains, which contain no ionic groups, relax with a smaller activation energy. Relaxation of these chain segments leads to a dilution of the entanglement network, and a plateau modulus below that for highly

  14. Intercomparison of peroxy radical measurements obtained at atmospheric conditions by laser-induced fluorescence and electron spin resonance spectroscopy

    Directory of Open Access Journals (Sweden)

    A. Hofzumahaus

    2009-03-01

    Full Text Available Measurements of hydroperoxy radical (HO2 and organic peroxy radical (RO2 concentrations were performed by two different techniques in the atmospheric simulation chamber SAPHIR in Jülich, Germany. The first technique was the well-established Matrix Isolation Electron Spin Resonance (MIESR, which provides absolute measurements with a time resolution of 30 min and high accuracy (10%, 2 σ. The other technique, ROxLIF, has been newly developed. It is based on the selective chemical conversion of ROx radicals (HO2 and RO2 to OH, which is detected with high sensitivity by laser-induced fluorescence (LIF. ROxLIF is calibrated by quantitative photolysis of water vapor at 185 nm and provides ambient measurements at a temporal resolution of 1 min and accuracy of 20% (2 σ. The measurements of HO2 and RO2 obtained by the two techniques were compared for two types of atmospheric simulation experiments. In one experiment, HO2 and CH3O2 radicals were produced by photooxidation of methane in air at tropospheric conditions. In the second experiment, HO2 and C2H5O2 were produced by ozonolysis of 1-butene in air at dark conditions. The radical concentrations were within the range of 16 to 100 pptv for HO2 and 12 to 45 pptv for RO2. Good agreement was found in the comparison of the ROxLIF and MIESR measurements within their combined experimental uncertainties. Linear regressions to the combined data set yield slopes of 1.02±0.13 (1 σ for RO2 and 0.98±0.08 (1 σ for HO2 without significant offsets. The results confirm the calibration of the ROxLIF instrument and demonstrate that it can be applied with good accuracy for measurements of atmospheric peroxy radical concentrations.

  15. Theoretical kinetics studies of two model reactions in biodiesel and diesel combustion

    Science.gov (United States)

    Sha, Yuan

    We use 1-methylallyl radical (CH3CH=CH-CH2· ↔ CH3C·H-CH=CH2·) as a model of allylic radicals generated during combustion of unsaturated diesel fuel molecules. The chemically activated isomerization of 1-methylallyl generated in the highly exothermic (˜35 kcal/mol) OH + trans-2-butene reaction was considered by using RRKM/Master Equation calculations from 0.01 to 100 atm and from 300 to 700 K. Density functional theory (DFT) with the M05-2X, M06-2X and B3LYP functionals are used for structures, energies, vibrational frequencies, anharmonic constants, and the torsional potentials of methyl rotations. The cis:trans ratio formed upon quenching the radicals were, as might be expected, dependent on the functional, but, were even more sensitive when an vibrations were treated as anharmonic. The fraction of cis- 1-methylallyl is significant, if not dominant at 300 -700 K and 0.01 -10 atm. Sensitivity studies were carried out to determine the dependence of the cis:trans ratio on the extent of chemical activation, treatment of the K-rotor as active or inactive, and the rate of collisional energy transfer. All these parameters significantly influence the cis:trans ratio. The 1,5 H-migration reaction of 3-hydroperoxy-1-propylperoxy radical (HOOCH2CH2CH2OO·) is a important as a model of a critical propagation step in diesel autoignition from alkanes or molecules with long alkyl tails. Its product may be the meta-stable alpha,gamma-dihydroperoxypropyl radical or, if unstable, OH + 3-hydroperoxypropanal. To study the possibly different tunneling effects of the two possible products, the quantum mechanical rate constants, including tunneling, are directly determined using semi-classical transition state theory (SCTST) at 200 K to 1700 K. Small-curvature tunneling (SCT) is to compute tunneling corrections to classical rate constants. The two reactions do not have obvious tunneling differences at above 700 K. Below 700 K, SCTST tunneling corrections are significantly higher

  16. Measurement of BVOCs by PTR-ToF-MS in a ponderosa pine forest during the BEACHON-ROCS campaign

    Science.gov (United States)

    Su, L.; Evans, T.; Knopf, D. A.; Mak, J. E.

    2012-12-01

    We present measurements of biogenic volatile organic compounds (BVOCs) using Proton Transfer Reaction Time-of-Flight Mass Spectrometer (PTR-ToF-MS) during the 2010 Bio-hydro-atmosphere interactions of Energy, Aerosols, Carbon, H2O, Organics & Nitrogen-Rocky Mountain Organic Carbon Study (BEACHON-ROCS) campaign in a ponderosa pine forest near Woodland Park, Colorado. BVOCs were continuously measured through the gradient sampling lines mounted at 1.8 m, 5.0 m, 8.5 m, 12.0 m, 17.7 m, and 25.3 m, respectively, of the Manitou Forest Observatory Chemistry Tower. 2-methyl-3-butene-2-ol (MBO) and the monoterpenes (MT) were identified as the major BVOCs emitted from the forest. The 5-minute averaged mixing ratios of MBO ranged from 0.03 to 3.9 ppbv, while mixing ratios of MT ranged from 0.02 to 3.8 ppbv, with an analytical precision of ±15%. The mixing ratios of MBO were highest during the daytime, with the maximum concentrations occurred right under the canopy top, decreasing towards the ground and above the canopy. The diurnal variations of MT mixing ratios showed an opposite pattern compared to MBO, with nighttime values significantly higher than during the daytime. The high nighttime mixing ratios of MT could be due to the sufficient temperature-dependent emission together with lack of oxidation and small vertical transport. MT usually accumulated near the ground level and decreased vertically towards the canopy top. Soil enclosure measurements were performed to characterize the needle litter emission of BVOCs. The flux of MT from needle litter were quantified and showed a clear temperature dependency. The highest flux of MT from needle litter occurred in the morning (09:00-12:00 MST), while during the nighttime the flux was significantly reduced. Measurements of BVOCs gradients throughout the canopy together with ground needle litter emissions could provide a better understanding of the contribution to above-canopy emission of BVOCs from different sources.

  17. 聚丁烯-1/高岭土纳米复合材料的力学性能及其非等温结晶动力学研究%Mechanical Properties and Non%isothermal Crystallization Kinetics of PB-1/kaolin Nanocomposites

    Institute of Scientific and Technical Information of China (English)

    张俊平; 杨继搞; 薛美玲

    2011-01-01

    The poly (1-butene) (PB-1)/kaolin nanocomposites were prepared by meltmixing. The dispersity of nano-kaolin was observed by SEM, and the effect of nano-kaolin content on the non-isothermal crystallization behavior and its kinetics of filled PB-1 were investigated by DSC method. The results indicate that nano-kaolin has better dispersity in PB-1/kaolin nanocomposites when the mass concentration of nano-kaolin was 2%, and nano-kaolin dispersion in the matrix of PB-1 reached a nanometer yardstick.There was slight agglomeration phenomenon when the mass concentration of nano-kaolin was 6%. The tensile strength achieved the maximum value when the concentration of nano-kaolin was 5%, and the elongation at break, the flexural strength and the flexural modulus were best when the mass concentration of nano-kaolin was 4%. DSC shows that the crystallization process of PB-1/kaolin nanocomposites were significantly inhibited when the mass concentration of nano-kaolin was more than 2 %, but the nucleation and three-dimensional growth mechanism of spherulites keep invariant.%采用熔融共混法制备了聚丁烯-1/高岭土(PB-1/kaolin)纳米复合材料,运用SEM、DSC等分析了高岭土在PB-1中的分散以及高岭土用量对PB-1结晶行为和结晶动力学的影响.研究结果表明,当高岭土质量分数为2%时,高岭土在PB-1中呈纳米级分散;质量分数为6%时,出现轻微团聚现象.拉伸强度在高岭土质量分数为5%时达到最大值,而断裂伸长率、弯曲强度和弯曲模量在高岭土质量分数为4%左右时最佳.DSC结果表明,当高岭土质量分数超过2%时,显著地抑制了PB-1的结晶过程,但球晶的成核机制和三维生长方式不变.

  18. 蓖麻叶挥发油化学成分分析%Analysis of chemical compositions of the essential oil in the leaf of Ricinus communis

    Institute of Scientific and Technical Information of China (English)

    陈月华; 陈利军; 石庆锋

    2012-01-01

    采用水蒸汽蒸馏法从蓖麻叶中提取挥发油,利用CC—MS联用仪对蓖麻叶挥发油的化学成分进行研究,共分离到52个组分,鉴定了其中的31个,占挥发油总量的77.223%。蓖麻叶挥发油主要成分是壬醛(14.718%)、二环[3.2.0]庚-2-酮(7.773%)、2,4-癸二烯醛(6.237%)、(E)-4-(2,6,6-三甲基-1-环己烯-l-基)-3-丁烯-2-酮(6.056%)、(E)-2-癸醛(5.967%)、(E)-6,10-二甲基-5,9-十-碳二烯-2-酮(5.063%)等。%To analyze the chemical compositions of the essential oil in the leaf of Ricinus communis, the essential oil was extracted from the leaf of R. communis by steam distillation, and then an analysis was conducted by applying GC - MS. The result shows that 52 ingredients have been found, and 31 of them have been identified, accounting for 77.223% of the total essential oil. The main chemical components of the leaf of R. communis are: Nonanal( 14. 718% ) ,Bicyclo [ 3.2.0 ] heptan - 2 - one (7. 773 % ), 2,4 - Decadienal ( 6. 237 % ), 3 -Buten - 2 - one, 4 - ( 2,6,6 - trimethyl - 1 - cyclohexen - 1 - yl) - , (E) - (6. 056% ) ,2 - Decenal, (E) - (5. 967% ) ,5,9 - Undecadien - 2 - one, 6,10 - dime- thyl -, (E) - (5.063%)etc.

  19. Mid-IR Absorption Cross-Section Measurements of Hydrocarbons

    KAUST Repository

    Alrefae, Majed Abdullah

    2013-05-01

    Laser diagnostics are fast-response, non-intrusive and species-specific tools perfectly applicable for studying combustion processes. Quantitative measurements of species concentration and temperature require spectroscopic data to be well-known at combustion-relevant conditions. Absorption cross-section is an important spectroscopic quantity and has direct relation to the species concentration. In this work, the absorption cross-sections of basic hydrocarbons are measured using Fourier Transform Infrared (FTIR) spectrometer, tunable Difference Frequency Generation laser and fixed wavelength helium-neon laser. The studied species are methane, methanol, acetylene, ethylene, ethane, ethanol, propylene, propane, 1-butene, n-butane, n-pentane, n-hexane, and n-heptane. The Fourier Transform Infrared (FTIR) spectrometer is used for the measurements of the absorption cross-sections and the integrated band intensities of the 13 hydrocarbons. The spectral region of the spectra is 2800 – 3400 cm-1 (2.9 – 3.6 μm) and the temperature range is 673 – 1100 K. These valuable data provide huge opportunities to select interference-free wavelengths for measuring time-histories of a specific species in a shock tube or other combustion systems. Such measurements can allow developing/improving chemical kinetics mechanisms by experimentally determining reaction rates. The Difference Frequency Generation (DFG) laser is a narrow line-width, tunable laser in the 3.35 – 3.53 μm wavelength region which contains strong absorption features for most hydrocarbons due to the fundamental C-H vibrating stretch. The absorption cross-sections of propylene are measured at seven different wavelengths using the DFG laser. The temperature range is 296 – 460 K which is reached using a Reflex Cell. The DFG laser is very attractive for kinetic studies in the shock tube because of its fast time response and the potential possibility of making species-specific measurements. The Fixed wavelength

  20. Emissions of BVOC from Lodgepole Pine in response to Mountain Pine Beetle attack in high and low mortality forest stands

    Directory of Open Access Journals (Sweden)

    T. R. Duhl

    2012-07-01

    Full Text Available In this screening study biogenic volatile organic compound (BVOC emissions from intact branches of lodgepole pine (Pinus contorta trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site observed seasonal variability in emissions. A brief site comparison is made of the hydrological characteristics and prior disturbances (both natural and man-made at the sites. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQT compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly-infested trees. SQT profiles differed between the two sites, and, like monoterpene and oxygenated VOC profiles, varied through the season For the low-mortality site in which repeated measurements were made over the course the early summer-late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT, with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of methyl-3-buten-2-ol had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late-season MPB survivors, in

  1. Emissions of BVOC from lodgepole pine in response to mountain pine beetle attack in high and low mortality forest stands

    Directory of Open Access Journals (Sweden)

    T. R. Duhl

    2013-01-01

    Full Text Available In this screening study, biogenic volatile organic compound (BVOC emissions from intact branches of lodgepole pine (Pinus contorta trees were measured from trees at two forested sites that have been impacted differently by the mountain pine beetle (MPB, with one having higher mortality and the other with lower mortality. Differences in the amounts and chemical diversity of BVOC between the two sites and from apparently healthy trees versus trees in different stages of MPB attack are presented, as well as (for one site observed seasonal variability in emissions. A brief comparison is made of geological and climatic characteristics as well as prior disturbances (both natural and man-made at each site. Trees sampled at the site experiencing high MPB-related tree mortality had lower chemodiversity in terms of monoterpene (MT emission profiles, while profiles were more diverse at the lower-mortality site. Also at the higher-mortality site, MPB-infested trees in various stages of decline had lower emissions of sesquiterpenes (SQTs compared to healthy trees, while at the site with lower mortality, MPB-survivors had significantly higher SQT emissions during part of the growing season when compared to both uninfested and newly infested trees. SQT profiles differed between the two sites and, like monoterpene and oxygenated VOC profiles, varied through the season. For the low-mortality site in which repeated measurements were made over the course of the early summer–late fall, higher chemical diversity was observed in early- compared to late-season measurements for all compound classes investigated (MT, oxygenated VOC, and SQT, with the amount of change appearing to correlate to the MPB status of the trees studied. Emissions of 2-methyl-3-buten-2-ol (MBO had a distinct seasonal signal but were not much different between healthy or infested trees, except in trees with dead needles, from which emissions of this compound were negligible, and in late

  2. Molecular analysis of volatile metabolites released specifically by staphylococcus aureus and pseudomonas aeruginosa

    Directory of Open Access Journals (Sweden)

    Filipiak Wojciech

    2012-06-01

    Full Text Available Abstract Background The routinely used microbiological diagnosis of ventilator associated pneumonia (VAP is time consuming and often requires invasive methods for collection of human specimens (e.g. bronchoscopy. Therefore, it is of utmost interest to develop a non-invasive method for the early detection of bacterial infection in ventilated patients, preferably allowing the identification of the specific pathogens. The present work is an attempt to identify pathogen-derived volatile biomarkers in breath that can be used for early and non- invasive diagnosis of ventilator associated pneumonia (VAP. For this purpose, in vitro experiments with bacteria most frequently found in VAP patients, i.e. Staphylococcus aureus and Pseudomonas aeruginosa, were performed to investigate the release or consumption of volatile organic compounds (VOCs. Results Headspace samples were collected and preconcentrated on multibed sorption tubes at different time points and subsequently analyzed with gas chromatography mass spectrometry (GC-MS. As many as 32 and 37 volatile metabolites were released by S. aureus and P. aeruginosa, respectively. Distinct differences in the bacteria-specific VOC profiles were found, especially with regard to aldehydes (e.g. acetaldehyde, 3-methylbutanal, which were taken up only by P. aeruginosa but released by S. aureus. Differences in concentration profiles were also found for acids (e.g. isovaleric acid, ketones (e.g. acetoin, 2-nonanone, hydrocarbons (e.g. 2-butene, 1,10-undecadiene, alcohols (e.g. 2-methyl-1-propanol, 2-butanol, esters (e.g. ethyl formate, methyl 2-methylbutyrate, volatile sulfur compounds (VSCs, e.g. dimethylsulfide and volatile nitrogen compounds (VNCs, e.g. 3-methylpyrrole. Importantly, a significant VOC release was found already 1.5 hours after culture start, corresponding to cell numbers of ~8*106 [CFUs/ml]. Conclusions The results obtained provide strong evidence that the detection and perhaps even

  3. Genotoxicity of 1,3-butadiene and its epoxy intermediates.

    Science.gov (United States)

    Walker, Vernon E; Walker, Dale M; Meng, Quanxin; McDonald, Jacob D; Scott, Bobby R; Seilkop, Steven K; Claffey, David J; Upton, Patricia B; Powley, Mark W; Swenberg, James A; Henderson, Rogene F

    2009-08-01

    Current risk assessments of 1,3-butadiene (BD*) are complicated by limited evidence of its carcinogenicity in humans. Hence, there is a critical need to identify early events and factors that account for the heightened sensitivity of mice to BD-induced carcinogenesis and to deter-mine which animal model, mouse or rat, is the more useful surrogate of potency for predicting health effects in BD-exposed humans. HEI sponsored an earlier investigation of mutagenic responses in mice and rats exposed to BD, or to the racemic mixture of 1,2-epoxy-3-butene (BDO) or of 1,2,3,4-diepoxybutane (BDO2; Walker and Meng 2000). In that study, our research team demonstrated (1) that the frequency of mutations in the hypoxanthine-guanine phosphoribosyl transferase (Hprt) gene of splenic T cells from BD-exposed mice and rats could be correlated with the species-related differences in cancer susceptibility; (2) that mutagenic-potency and mutagenic-specificity data from mice and rats exposed to BD or its individual epoxy intermediates could provide useful information about the BD metabolites responsible for mutations in each species; and (3) that our novel approach to measuring the mutagenic potency of a given chemical exposure as the change in Hprt mutant frequencies (Mfs) over time was valuable for estimating species-specific differences in mutagenic responses to BD exposure and for predicting the effect of BD metabolites in each species. To gain additional mode-of-action information that can be used to inform studies of human responses to BD exposure, experiments in the current investigation tested a new set of five hypotheses about species-specific patterns in the mutagenic effects in rodents of exposure to BD and BD metabolites: 1. Repeated BD exposures at low levels that approach the occupational exposure limit for BD workers (set by the U.S. Occupational Safety and Health Administration) are mutagenic in female mice. 2. The differences in mutagenic responses of the Hprt gene to BD

  4. The Low Temperature Oxidation of 2,7-Dimethyloctane in a Pressurized Flow Reactor

    Science.gov (United States)

    Farid, Farinaz

    n-decane resulted primarily in the formation of ethene near the NTC start, propene and isobutene were the major olefins produced from 2,7-DMO. A comparative analysis of experimental data with respect to a detailed chemical kinetic model for 2,7-DMO was performed and discrepancies were noted. Based on these results, a collaborative effort with Dr. Charles Westbrook (Lawrence Livermore National Laboratory) was initiated to refine the model predictions in the low temperature and NTC regimes. The effort resulted in an updated version of the 2,7-DMO mechanism, improving some of the key features such as calculated CO2 profile and final yields of iso-butene over the studied range of temperature. Fuel pyrolysis in the intermediate temperature regime, 850 -- 1000 K, also was investigated for the first time in the PFR facility. However, preliminary n-decane experiments measured only a small amount of fuel decomposition, indicating that higher temperature operation would be beneficial. The major species produced from n-decane decomposition, in descending order of molar fraction, were ethene, propene, and 1-butene. These results were compared with the predictions of two existing chemical kinetic models and the sources of variations between the experiments and the models as well as among the mechanisms were investigated. At 1000 K, the mechanisms predicted higher levels of fuel depletion and ethene production. Also, while the mechanisms were similar in their predicted pathways for fuel depletion and formation of ethene, inconsistencies were observed in relative contribution of these pathways to the final yields as well as the rate parameter determination for several sensitive reactions with respect to n-decane and ethene. Overall, the research aided in achieving a data set quantifying the oxidation characteristics of 2,7-DMO (and n-decane for comparison) as well as an elucidation of critical reaction pathways based on experimental results. Preliminary pyrolysis experiments were

  5. VOC and VOX in fluid inclusions of quartz: New chemical insights into hydrothermal vein mineralization by GC-MS and GC-IRMS measurements

    Science.gov (United States)

    Sattler, Tobias; Kirnbauer, Thomas; Keppler, Frank; Greule, Markus; Fischer, Jan; Spiekermann, Patrik; Schreiber, Ulrich; Mulder, Ines; Schöler, Heinz Friedrich

    2015-04-01

    Fluid inclusions (FIs) in minerals are known to contain a variety of different liquids, gases, and solids. The fluids get trapped during mineral growth and can preserve the original mineral-forming fluid or fluids of later events. A new analytical technique developed by Mulder et al. (2013) [1] allows to measure trace gases in FIs. For the measurements, grains of 3-5 mm diameter are ground in an airtight grinding device, releasing the volatiles from FIs into the gas phase, where they can be measured by GC-MS, GC-FID and GC-IRMS. The Taunus covers the southeastern part of the thrust-and-fold-belt of the Rhenish Massif (Germany). The Variscan rock sequences comprise sedimentary and volcanic units ranging from Ordovician to Lower Carboniferous. Several types of hydrothermal mineralization can be distinguished, which are - in regard to the Variscan orogeny - pre-orogenic, orogenic, late-orogenic, post-orogenic and recent in age [2]. They include SEDEX, vein, Alpine fissure, disseminated and stockwerk mineralizations. Thus, the Taunus mineralizations enable investigations of different hydrothermal systems at different age in one region. For most of them extensive studies of stable and radiogenic isotopes exist. Quartz crystals of post-orogenic quartz veins and Pb-Zn-Cu bearing veins [3] were selected for our FI investigation. Sulphur containing compounds like COS and CS2 dominate the FIs but there are also volatile hydrocarbons (VOC) like different butenes, benzene, toluene and cyclopentene that were found very often. In some samples volatile halogenated organic carbons (VOX) like chloro- and bromomethane were found. Some FIs even contain iodomethane, chlorobenzene, vinyl chloride and -bromide. The non-fossil-fuel subsurface chemistry of VOC and VOX is not fully understood. There are a lot of unknown geogenic sources [4][5]. For a better understanding δ13C- and δ2H-values of CH4 were measured by GC-IRMS to examine if the detected organic compounds are formed biotic

  6. Session 4: Improved middle distillate selectivity using pre-treated catalytic cracking catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Trimm, D.L.; Chia, D.A. [New South Wales Univ., School of Chemical Engineering and Industrial Chemistry, Sydney (Australia)

    2004-07-01

    correlate well with the number of paired next nearest neighbour (NNN) Al sites on the surface. If deactivation with ammonia reduces the number of such sites, hydrogen transfer reactions, as assessed by the ratio of paraffins to light olefins and of iso-butane to iso-butene, should decrease. This was found to be the case. Both the selectivity to light olefins and the paraffin: olefin ratio decreased over pre-coked catalyst. The yield of light olefins decreased as coking increased, an observation consistent with mass transfer limitations favouring the conversion of olefins to coke. Pre-coking was also found to affect acid catalysed reactions, as seen by comparison of the isomerization reaction products. Both ammonia and coke pre-treatment reduce the ratio of branched: linear paraffins, and emphasise the role of coke both as a site deactivating agent and a pore blocking agent. It is clear that pre-coking equilibrated catalyst does not improve middle distillate yield, in contrast to reported results based on fresh catalyst. This is probably due to deactivation of highly active catalytic sites during equilibration, a suggestion supported by temperature programmed desorption studies of fresh and equilibrated catalyst. (authors)

  7. Development of biogenic VOC emission inventories for the boreal forest

    Energy Technology Data Exchange (ETDEWEB)

    Tarvainen, V.

    2008-07-01

    . For the first time, Scots pine was found to emit also sesquiterpenes and 2-methyl- 3-buten-2-ol (MBO), with maximum emissions in the summer months. According to the model calculations the main compounds emitted by the boreal forest throughout the growing season in Finland are alpha- and beta-pinene and DELTA3-carene, with a strong contribution of sabinene by the deciduous trees in summer and autumn. The emissions follow the course of the temperature and are highest in the south boreal zone with a steady decline towards the north. The isoprene emissions from the boreal forest are fairly low - the main isoprene emitters are the low emitting Norway spruce and the high emitting willow and aspen, whose foliage, however, only represents a very small percentage of the boreal leaf biomass. This work also includes the first estimate of sesquiterpene emissions from the boreal forest. The sesquiterpene emissions initiate after midsummer and are of the same order of magnitude as the isoprene emissions. At the annual level, the total biogenic emissions from the forests in Finland are approximately twice the anthropogenic VOC emissions. (orig.)

  8. Multinuclear group 4 catalysis: olefin polymerization pathways modified by strong metal-metal cooperative effects.

    Science.gov (United States)

    McInnis, Jennifer P; Delferro, Massimiliano; Marks, Tobin J

    2014-08-19

    Polyolefins are produced today catalytically on a vast scale, and the manufactured polymers find use in everything from artificial limbs and food/medical packaging to automotive and electrical components and lubricants. Although polyolefin monomers are typically cheap (e.g., ethylene, propylene, α-olefins), the resulting polymer properties can be dramatically tuned by the particular polymerization catalyst employed, and reflect a rich interplay of macromolecular chemistry, materials science, and physics. For example, linear low-density polyethylene (LLDPE), produced by copolymerization of ethylene with linear α-olefin comonomers such as 1-butene, 1-hexene, or 1-octene, has small but significant levels of short alkyl branches (C2, C4, C6) along the polyethylene backbone, and is an important technology material due to outstanding rheological and mechanical properties. In 2013, the total world polyolefin production was approximately 211 million metric tons, of which about 11% was LLDPE. Historically, polyolefins were produced using ill-defined but highly active heterogeneous catalysts composed of supported groups 4 or 6 species (usually halides) activated by aluminum alkyls. In 1963, Karl Ziegler and Giulio Natta received the Nobel Prize for these discoveries. Beginning in the late 1980s, a new generation of group 4 molecule-based homogeneous olefin polymerization catalysts emerged from discoveries by Walter Kaminsky, a team led by James Stevens at The Dow Chemical Company, this Laboratory at Northwestern University, and a host of talented groups in Germany, Italy, Japan, the United Kingdom, and the United States. These new "single-site" catalysts and their activating cocatalysts were far better defined and more rationally tunable in terms of structure, mechanism, thermodynamics, and catalyst activity and selectivity than ever before possible. An explosion of research advances led to new catalysts, cocatalysts, deeper mechanistic understanding of both the

  9. Characteristics of VOCs and Their Photochemical Reactivity in Autumn in Nanjing Northern Suburb%南京北郊秋季VOCs及其光化学特征观测研究

    Institute of Scientific and Technical Information of China (English)

    李用宇; 朱彬; 安俊琳; 高晋徽; 夏丽; 张祥志; 秦玮; 汤莉莉

    2013-01-01

    采用GC5000挥发性有机物在线监测系统和EMS系统,于2011年11月在南京北郊开展了为期一个月的连续观测,分别测量了大气中56种VOCs组分和反应性气体(NOx、CO和O3).结果表明,南京北郊的VOCs小时平均体积分数大约在48.17×10-9,日变化呈明显双峰型特征,受机动车影响比较显著,极小值出现在下午16:00,白天与O3浓度曲线呈负相关;VOCs的平均OH消耗速率常数约为3.26 ×l0-12cm3·(molecule,s)-1,最大增量反应活性约为3.26 mol· mol-1;烯烃对OH消耗速率(LOH)和臭氧生成潜势(OFP)贡献率最大,芳香烃次之,而烷烃在大气中含量最为丰富,却并不是LOH和OFP主要贡献者;VOCs关键活性组分是乙烯、丙烯、1-丁烯、间,对-二甲苯及异戊二烯等物质;臭氧生成过程处于VOCs控制区.%A continuous observation campaign was carried out with the GC5000 volatile organics online monitoring system and the EMS system for one month in November 2011 in the northern suburb of Nanjing,and 56 VOC components and reactive gases (NOx,CO and O3) were measured.The results showed that the VOC hourly averaged volume fraction in Nanjing northern suburb was about 48.17 ×10-9,and the minimum value of VOCs occurred at 16:00.The diurnal variation showed a bimodal characteristic,indicating the significant impact of motor vehicle emission.The VOC concentration and O3 concentration exhibited negative correlation in the daytime.The average OH consumption rate of VOCs was approximately 3.26 × 10-12 cm3 · (molecule,s)-1,and the largest incremental reactivity was about 3.26 mol· mol-1 ; Alkenes contributed the largest parts of the OH consumption rate (LOH) and the ozone formation potential (OFP),followed by aromatics.Although alkanes were the most abundant components of VOCs in the atmosphere,it is not the main contributor of LOH and OFP.The key active components in VOCs were ethylene,propylene,1-butene,m,p-xylene and isoprene,etc.The dominant factor

  10. 载体酸性对Mo/HZSM-5-Al2O3催化剂上烯烃歧化反应性能的影响%Effects of Support Acidity on the Catalytic Performance of Mo/HZSM-5-Ai2O3 Catalysts in Olefin Metathesis

    Institute of Scientific and Technical Information of China (English)

    张大洲; 李秀杰; 刘盛林; 朱向学; 辛文杰; 谢素娟; 曾蓬; 徐龙伢

    2011-01-01

    Mo/HZSM-5-Al2O3 catalyst samples, where the HZSM-5 had different Si/Al ratios (12, 42, and 213), were prepared and evaluated in a fixed-bed reactor. Effects of support acidity changes on the catalytic performance of Mo/HZSM-5-Al2O3 in the metathesis of ethene and 2-butene to propene were investigated. NH3 temperature-programmed desorption and pyridine infrared spectra revealed that the differences in support acidity led to the different anchoring modes of Mo species on the composite supports. Quick deactivation phenomena were ob served on Mo/HZSM-5-Al2O3 (Si/Al = 12) due to the high acidity density of the catalyst. For Mo/HZSM-5-Al2O3 (Si/Al = 213), more Mo species dispersed on the alumina in octahedral form and those locating in the zeolite channels existed in the state of (Mo2Os)2+ clusters evi denced by ultraviolet-visible diffuse reflectance spectroscopy and H2 temperature-programmed reduction results. Such distribution was linked with the low metathesis activity and the appearance of the induction period on Mo/HZSM-5-Al2O3 (Si/Al = 213). Mo/HZSM-5-Al2O3 (Si/Al = 42) sample demonstrated the best catalytic activity and reaction stability among the three samples. This was attributed to its suitable acidity amount and optimal distribution of Mo species on the support.%在固定床反应器上考察了Mo/HZSM-5-Al2O3催化剂上乙烯与2-丁烯歧化制丙烯反应的性能.结合X射线衍射、NH3程序升温脱附、吡啶吸附红外光谱、H2程序升温还原和程序升温氧化等表征结果发现,载体酸性的差异导致催化剂酸性和 Mo物种落位方式不同.载体酸性较强时,催化剂积炭严重,反应稳定性差;载体酸性较弱时,Mo物种在分子筛孔道内以(Mo2O5)2+团簇形式存在,而在Al2O3表面形成较多易还原的六配位Mo物种,催化活性低,并呈现出一定的诱导期;适中酸性的载体有利于Mo物种的分散和活化,表现出了最佳的歧化反应活性.

  11. 钼负载量对FCC干气和混合C4组合进料制丙烯催化剂反应性能的影响%INFLUENCE OF MoO3 CONTENT ON THE CATALYTIC PERFORMANCE OF CATALYST FOR PREPARING PROPENE FROM COMBINED FEED OF FCC DRY GAS AND MIXED C4

    Institute of Scientific and Technical Information of China (English)

    庞新迎; 李春义

    2011-01-01

    基于提高烯烃利用率和增产丙烯的目的,在C4烯烃裂解制丙烯工艺中,将FCC干气和混合C4按一定比例混合后作为进料.采用初湿浸渍法向ZSM-5分子筛催化剂中引入MoO3,以实现裂解反应与歧化反应的耦合.采用X射线衍射技术(XRD)、Py-FTIR光谱及BET技术对MoO3/ZSM-5-Al2O3催化剂进行表征.结果表明,钼的引入对催化剂的酸性质、表面性质和孔分布均存在一定的影响.将固定床微反结果与钼负载量相关联,在反应温度为450℃、干气和混合C4体积比为4、原料气体积空速为120 min(-1)的条件下,发现钼的引入有利于乙烯和2-丁烯间歧化反应的发生,在一定范围内有利于丙烯收率的提高,丙烯收率在销负载量(ω)为4%时最大,约为27.85%.%In order to enhance the utilization of olefins and to produce more propene,FCC dry gas was introduced as partial feed in the process of preparing propene from mixed C4. A series of ZSM-5 zeolite catalysts loaded with various MoO3 contents were prepared by incipient wetness procedure to realize the coupling of cracking reactions and metathesis reactions. The MoO3/ZSM-5/Al2O3 catalysts were characterized by XRD, Py-FTIR and BET method to study the effect of MoO3 content on the catalyst performance. Test results showed that the acidity, surface property and pore structure of the catalyst were affected by the loading of MoO3. Based on correlating the evaluation results of fixed bed microreactor and the MoO3 contents,it was found that under the conditions of a reaction temperature of 450 ℃ ,a dry gas/mixed C4 volume ratio of 4 and a GHSV of 120 min-1, MoO3/ZSM-5/Al2O3 catalyst with suitable MoO3 content was in favor of promoting metathesis reactions between ethene and 2-butene,and thus the propene yield was increased. A maximum propene yield of 27.85 % was obtained over a catalyst with a MoO3 content of 4%.

  12. Multinuclear group 4 catalysis: olefin polymerization pathways modified by strong metal-metal cooperative effects.

    Science.gov (United States)

    McInnis, Jennifer P; Delferro, Massimiliano; Marks, Tobin J

    2014-08-19

    Polyolefins are produced today catalytically on a vast scale, and the manufactured polymers find use in everything from artificial limbs and food/medical packaging to automotive and electrical components and lubricants. Although polyolefin monomers are typically cheap (e.g., ethylene, propylene, α-olefins), the resulting polymer properties can be dramatically tuned by the particular polymerization catalyst employed, and reflect a rich interplay of macromolecular chemistry, materials science, and physics. For example, linear low-density polyethylene (LLDPE), produced by copolymerization of ethylene with linear α-olefin comonomers such as 1-butene, 1-hexene, or 1-octene, has small but significant levels of short alkyl branches (C2, C4, C6) along the polyethylene backbone, and is an important technology material due to outstanding rheological and mechanical properties. In 2013, the total world polyolefin production was approximately 211 million metric tons, of which about 11% was LLDPE. Historically, polyolefins were produced using ill-defined but highly active heterogeneous catalysts composed of supported groups 4 or 6 species (usually halides) activated by aluminum alkyls. In 1963, Karl Ziegler and Giulio Natta received the Nobel Prize for these discoveries. Beginning in the late 1980s, a new generation of group 4 molecule-based homogeneous olefin polymerization catalysts emerged from discoveries by Walter Kaminsky, a team led by James Stevens at The Dow Chemical Company, this Laboratory at Northwestern University, and a host of talented groups in Germany, Italy, Japan, the United Kingdom, and the United States. These new "single-site" catalysts and their activating cocatalysts were far better defined and more rationally tunable in terms of structure, mechanism, thermodynamics, and catalyst activity and selectivity than ever before possible. An explosion of research advances led to new catalysts, cocatalysts, deeper mechanistic understanding of both the

  13. Caracterização de polietilenos lineares de baixa densidade II: fracionamento por cristalização isotérmica a partir do estado fundido Linear low-density polyethylene characterization II: fractionation by multiple-step isothermal crystallization from the melting state

    Directory of Open Access Journals (Sweden)

    Antonio C. Quental

    2005-11-01

    copolymerization with ethene. The alpha-olefins commonly used are 1-butene, 1-hexene and 1-octene. Depending on the alpha-olefin and the catalyst used for the polymerization, LLDPE presents different microstructures which determine the thermal and mechanical properties. One simple and efficient method to evaluate the microstructure of LLDPE is the fractionation by Multiple-Step Isothermal Crystallization from Melting State conducted by DSC. This method is based on several steps of isothermal crystallization of the polymer on decreasing the temperature from the melt. This process favors the separation of the crystalline material into groups having different lamellae thickness depending on the amount and distribution of the alpha-olefin units in the macromolecular chains and on the molar mass. The melting endotherm of a fractionated sample is made up of the same number of peaks as the isothermal crystallization steps, which inform the relative comonomers distributions between different LLDPE chains. In this work, this methodology was applied to determine the relative comonomers distribution of different LLDPE. The isothermal temperature, temperature range and the time influence the efficiency of the fractionation and these parameters must be chosen according to the LLDPE microstructure.

  14. Hydrodesulfurization on Transition Metal Catalysts: Elementary Steps of C-S Bond Activation and Consequences of Bifunctional Synergies

    Science.gov (United States)

    Yik, Edwin Shyn-Lo

    convergence to a single phase is expected and predictable from thermodynamics at a given temperature and sulfur chemical potential, metastability of two phases can exist. We demonstrate, through extensive characterization and kinetic evidence, such behaviors exist in Re, where structural disparities between its phases lead to kinetic hurdles that prevent interconversions between layered ReSx nanostructures and sulfur-covered Re metal clusters. Such features allowed, for the first time, direct comparisons of reaction rates at identical conditions on two disparate phases of the same transition metal identity. Rigorous assessments of kinetic and selectivity data indicated that more universal mechanistic features persist across all catalysts studied, suggesting that differences in their catalytic activity were the result of different densities of HDS sites, which appeared to correlate with their respective metal-sulfur bond energies. Kinetic responses and product distributions indicated that the consumption of thiophene proceeds by the formation of a partially-hydrogenated surface intermediate, which subsequently produces tetrahydrothiophene (THT) and butene/butane (C4) via primary routes on similar types of sites. These sites are formed from desorption of weakly-bound sulfur adatoms on sulfur-covered metal surfaces, which can occur when the heat of sulfur adsorption is sufficiently low at high sulfur coverage as a result of increased sulfur-sulfur repulsive interactions. Relative stabilities and differences in the molecularity of the respective transition states that form THT and C4 dictate product distributions. THT desulfurization to form C4 occurs via readsorption and subsequent dehydrogenation, evidenced by secondary rates that exhibited negative H2 dependences. These behaviors suggest that C-S bond activation occurs on a partially (un)saturated intermediate, analogous to behaviors observed in C-C bond scission reactions of linear and cycloalkanes on hydrogen-covered metal

  15. Effects of dairy system, herd within dairy system, and individual cow characteristics on the volatile organic compound profile of ripened model cheeses.

    Science.gov (United States)

    Bergamaschi, M; Aprea, E; Betta, E; Biasioli, F; Cipolat-Gotet, C; Cecchinato, A; Bittante, G; Gasperi, F

    2015-04-01

    increased linearly during lactation, whereas octan-1-ol, 3-methyl-3-buten-1-ol, 2-butoxyethanol, 6-pentyloxan-2-one, and 2,6-dimethylpyrazine showed a more complex pattern during lactation. The effect of the number of lactations (parity) was significant for octan-1-ol, butanoic acid, and heptanoic acid. Finally, concentrations of octan-1-ol, 2-phenylethanol, pentanoic acid, and heptanoic acid increased with increasing daily milk yield, whereas dihydrofuran-2(3H)-one decreased. In conclusion, the volatile organic compound profile of model cheeses from the milk of individual cows was affected by dairy farming system and stage of lactation and, to lesser extent, by parity and daily milk yield. PMID:25682146

  16. 超临界CO2辅助聚合物加工%Supercritical CO2 assisted polymer processing

    Institute of Scientific and Technical Information of China (English)

    赵玲; 刘涛

    2013-01-01

    the CO2-assisted polymer processing. The cases include CO2 -induced crystallization of isotactic polypropylene and syndiotactic polypropylene, CO2-induced crystal phase transition of isotactic poly-1-butene, and how to use CO2-induced crystallization to manipulate melt strength of three linear polymers, i. e. , isotactic polypropylene,poly (lactic acid) and poly (ethylene terephthalate), to prepare the polymer foams with different structures.

  17. Characteristics of VOCs emitted from typical industrial fugitive%典型工业无组织源VOCs排放特征

    Institute of Scientific and Technical Information of China (English)

    王刚; 魏巍; 米同清; 王澎涛; 栾英男; 程水源; 李国昊; 李松

    2015-01-01

    The pharmaceutical factory, brewery and rubber factory were selected to measure the chemical characteristics of VOCs emissions from their different production processes. The results indicated that in the pharmaceutical factory, VOCs emitted from analgin synthesis and aminopyrine synthesis were mainly composed of benzene, toluene, styrene and other aromatics, and VOCs emitted from acetaminophen synthesis were mainly composed of C4-C6 alkanes. VOCs emitted from brewery and rubber factory were both characterized by toluene, ethylbenzene and p-xylene. Moreover, the maximum incremental reactivity method was applied to analysis the ozone formation potential of VOCs emissions from these factories. The dominant species for ozone formation were benzene, toluene and other aromatics for the analgin synthesis and aminopyrine synthesis in the pharmaceutical factory; c-2-Butene, toluene and isopentane for the acetaminophen synthesis in the pharmaceutical factory; toluene, ethylbenzene and m, p-xylene for the brewery and the rubber factory, respectively. The threshold of diluted multiples was also used to analysis the stench index of these VOCs emissions. The results showed that the odor pollution in the pharmaceutical and brewery was relatively slighter. However, the telescopic device and vulcanizing workshop in the rubber factory were influenced by a certain degree of odor pollution.%选取制药厂、酿酒厂和橡胶厂分析了不同工艺过程 VOCs 排放特征。结果表明,制药厂安乃近合成和氨基比林合成的 VOCs 排放以苯、甲苯和苯乙烯等苯系物为主,乙酰氨基酚合成的VOCs排放主要以C4~C6的烷烃为主,酿酒厂和橡胶厂VOCs排放均以甲苯、乙苯和间,对二甲苯为主。采用最大增量反应活性法对臭氧生成潜势进行分析,制药厂安乃近合成和氨基比林合成 VOCs 单位臭氧生成潜势以苯、甲苯等苯系物为主;乙酰氨基酚合成以顺-2-丁烯、甲苯和异戊烷为主

  18. Selective-Reagent-Ionization Mass Spectrometry: New Prospects for Atmospheric Research

    Science.gov (United States)

    Sulzer, Philipp; Jordan, Alfons; Hartungen, Eugen; Hanel, Gernot; Jürschik, Simone; Herbig, Jens; Märk, Lukas; Märk, Tilmann D.

    2014-05-01

    Proton-Transfer-Reaction Mass Spectrometry (PTR-MS), which was introduced to the scientific community in the 1990's, has quickly evolved into a well-established technology for atmospheric research and environmental chemistry [1]. Advantages of PTR-MS are i) high sensitivities of several hundred cps/ppbv, ii) detection limits at or below the pptv level, iii) direct injection sampling (i.e. no sample preparation), iv) response times in the 100 ms regime and v) online quantification. However, one drawback is a somehow limited selectivity, as in case of quadrupole mass filter based instruments only information about nominal m/z are available. In Time-Of-Flight (TOF) mass analyzer based instruments selectivity is drastically increased by a high mass resolution of up to 8000 m/Δm, but e.g. isomers still cannot be separated. In 2009 we introduced an advanced version of PTR-MS, which permits switching the reagent ions from H3O+ to NO+ and O2+, respectively [2]. This novel type of instrumentation was called Selective-Reagent-Ionization Mass Spectrometry (SRI-MS) and has been successfully used to separate isomers, e.g. the biogenic compounds isoprene and 2-methyl-3-buten-2-ol as shown by Karl et al. [3]. Switching the reagent ions dramatically increases selectivity and thus applicability of SRI-MS in atmospheric research. Here we report on the latest results utilizing an even more advanced embodiment of SRI-MS enabling the use of the additional reagent ions Kr+ and Xe+ [4]. With this technology important atmospheric compounds, such as CO2, CO, CH4, O2, etc. can be quantified and selectivity is increased even further. We present comparison data between diesel and gasoline car exhaust gases and quantitative data on indoor air for these compounds, which are not detectable with classical PTR-MS. Additionally, we show very recent examples of isomers which cannot be separated with PTR-MS but can clearly be distinguished with SRI-MS. Finally, we give an overview of ongoing SRI

  19. Eddy covariance emission and deposition flux measurements using proton transfer reaction - time of flight - mass spectrometry (PTR-TOF-MS): comparison with PTR-MS measured vertical gradients and fluxes

    Science.gov (United States)

    Park, J.-H.; Goldstein, A. H.; Timkovsky, J.; Fares, S.; Weber, R.; Karlik, J.; Holzinger, R.

    2013-02-01

    .1 μg C m-2 h-1), and m/z 69.071 (isoprene + 2-methyl-3-butene-2-ol, 1.8%, 5.3 μg C m-2 h-1). Low levels of emission and/or deposition (characterizing the biosphere-atmosphere exchange including both emission and deposition for a large range of BVOC and their oxidation products.

  20. 红树莓与黄树莓挥发性成分差异研究%Research on Red and Yellow Raspberries' Differences of Volatile Components

    Institute of Scientific and Technical Information of China (English)

    吴继军; 肖更生; 徐玉娟; 唐道邦; 温靖; 余元善

    2014-01-01

    ,Crithmene,.α-Myrcene,D-Limonene et al. Thirty-six species of higher levels of ketones,esters,aldehydes,alkenes substances were detetected,followed by higher levels ofβ-lonene, (E)-β-lonene,α-lonene,5-Hydrxoymethylfurfural, ethyl acetate,Nonanal,Longicyclene,(3E)-4-(2,6,6-Trimethyl-1,3-cyclohexadien-1-yl)-3-buten-2-one,α- Phellandrene, D-limonene,1,3,5,7-Cyclooctatetraene. Yellow raspberry and red raspberry volatile components were significantly different. Yellow raspberry can be used as a new kind of raspberry raw material for further development.

  1. La consommation de propylène en Europe occidentale Propylene Consumption in Western Europe

    Directory of Open Access Journals (Sweden)

    Barraqué M.

    2006-11-01

    'éthylène; - le craquage du méthanol. The needs of Western Europe for propylene used in petrochemistry are currently 7. 4 x 10 to the power of 6 metric tons per year. In the coming years, the average rate of increase should be about 1. 8 % per year. Hence in 1995 European petrochemicals should use about 8. 7 x 10 to the power of 6 tons of propylene,Most of this increase in consumption will be due to the sharp rise in polypropylene production and to a lesser extent in propylene oxide, isopropanol and 2-ethyl hexanol production. However, uses for acrylonitrile and cumene will remain fairly stable. Propylene consumption for butanol production should decrease. The share of propylene needs met by European steam crackers, which was 82% in 1986, should be less than 75% in 1995. It will be more and more necessary to turn to other sources of supply. In 1986 European refineries produced 1. 05 x 10 to the power of 6 tons of propylene used for petrochemicals, and imports amounted to 0. 3 x 10 to the power of 6 tons. In 1995 the difference between consumption and production by steam crackers could be beyond 2. 0 x 10 to the power of 6 tons. It seems improbable that catalytic cracking plants can make up for the deficit except if propylene yields were to increase a great deal. The construction of propylene/propane splitters can be expected along with an increase in imports. Likewise, due to the tension that risks could appear in propylene prices, the advantage of some synthesis routes now considered not to be profitable might increase. These new routes are :(a dehydrogenation of propane as is already being considered in other regions (Mexico, Indonesia, Malaysia;(b metathesis between ethylene and butenes-2, which themselves can be produced from ethylene;(c methanol cracking.

  2. Hydrodesulfurization on Transition Metal Catalysts: Elementary Steps of C-S Bond Activation and Consequences of Bifunctional Synergies

    Science.gov (United States)

    Yik, Edwin Shyn-Lo

    convergence to a single phase is expected and predictable from thermodynamics at a given temperature and sulfur chemical potential, metastability of two phases can exist. We demonstrate, through extensive characterization and kinetic evidence, such behaviors exist in Re, where structural disparities between its phases lead to kinetic hurdles that prevent interconversions between layered ReSx nanostructures and sulfur-covered Re metal clusters. Such features allowed, for the first time, direct comparisons of reaction rates at identical conditions on two disparate phases of the same transition metal identity. Rigorous assessments of kinetic and selectivity data indicated that more universal mechanistic features persist across all catalysts studied, suggesting that differences in their catalytic activity were the result of different densities of HDS sites, which appeared to correlate with their respective metal-sulfur bond energies. Kinetic responses and product distributions indicated that the consumption of thiophene proceeds by the formation of a partially-hydrogenated surface intermediate, which subsequently produces tetrahydrothiophene (THT) and butene/butane (C4) via primary routes on similar types of sites. These sites are formed from desorption of weakly-bound sulfur adatoms on sulfur-covered metal surfaces, which can occur when the heat of sulfur adsorption is sufficiently low at high sulfur coverage as a result of increased sulfur-sulfur repulsive interactions. Relative stabilities and differences in the molecularity of the respective transition states that form THT and C4 dictate product distributions. THT desulfurization to form C4 occurs via readsorption and subsequent dehydrogenation, evidenced by secondary rates that exhibited negative H2 dependences. These behaviors suggest that C-S bond activation occurs on a partially (un)saturated intermediate, analogous to behaviors observed in C-C bond scission reactions of linear and cycloalkanes on hydrogen-covered metal

  3. Improved synthesis and pharmacological evaluation of racemic 11-demethylcalanolide A%消旋11-去甲胡桐素A的合成方法改进及其药理学评价

    Institute of Scientific and Technical Information of China (English)

    王琳; 彭宗根; 周春梅; 高琦; 刘刚; 张兴权; 陈鸿珊; 陶佩珍; 李燕; 白玉; 扈金萍; 马涛; 邢振堂

    2008-01-01

    An improved and practical synthesis of racemic 11-demethylcalanolide A [(±)-1] was developed. This improved process involved Pechmann reaction on phloroglucinol with ethyl butyrylacetate to give 5, 7,-dihydroxy-4-n-propylcoumarin(3). Poly phosphoric acid (PPA) catalyzed acylation of compound(3) with crotonic acid, then intramolecular cyclization was achieved simultaneously in one step to afford the key intermediate chromanone(4). A microwave assisted synthetic method preparing chromene(6) using chromenynation of chromanone(4) with 1, 1-diethoxy-methyl-2-butene was conducted. Luche reduction of chromene(6) using NaBH with CeCl3·7H2O preferably gave (±)-1. The overall yield of this four step synthesis of (±)-1 was around 32% increasing one fold more than that of the previous method. An in vitro investigation showed that (±)-1 exhibited inhibitory activities against both wild-type and drug-resistant HIV-1 in HIV-1 RT and cell culture assay, and significant synergistic effects in combination with AZT, T-20, and indinavir. Its LD50 of acute toxicity in mice by intragastric administration and by intraperitoneal injection were 735.65mg·kg-1 and 525.10mg·kg-1, respectively. The C and AUC were 0.54μg·mL-1 and 1.08(μg·mL-1)·h, respectively. The dynamics study of the inhibition of mice sera on HIV-1 RT showed that mice treated with 100mg·kg-1 (±)-1 once intraperitoneally were similar to that of 5mg·kg-1 of known clinical effective anti-HIV-1 drug neverapine. The results suggested that further investigation of the anti-HIV candidate (±)-1 was warranted.%本文发展一个实用改进方法以合成具有抗人免疫缺陷病毒(HIV-1)的天然产物的类似物11-去甲胡桐素A[(±)-1],方法改进包括以间苯三酚为起始原料与正丁酰乙酸乙酯在饱和氯化氢甲醇存在下,经过Pechmann反应生成5,7-双羟基-4-正丙基香豆素(3),再与巴豆酸用多聚磷酸作溶剂及催化剂进行酰化,同时分子内环合得到收率为70%关

  4. Methanol to hydrocarbons reaction over HZSM-22 and SAPO-11:Effect of catalyst acid strength on reaction and deactivation mechanism%HZSM-22和SAPO-11催化甲醇转化制烯烃(MTH)反应:酸强度对反应和失活机理的影响

    Institute of Scientific and Technical Information of China (English)

    王金棒; 张雯娜; 武新强; 郭新闻; 刘中民; 李金哲; 徐舒涛; 郅玉春; 魏迎旭; 何艳丽; 陈景润; 张默之; 王全义

    2015-01-01

    -ring channels, but have different acidic strengths. Comparison studies and 12C/13C isotopic switching experiments were conducted to eval-uate the influence of the acidic strength of the catalyst on the conversion of methanol, as well as its deactivation mechanism. Although the conversion of methanol proceeded via an alkene methyla-tion-cracking pathway over both catalysts, the acidity of the catalysts had a significant impact on the conversion and product distribution of these reactions. The stability of the catalysts varied with temperature. The catalysts were deactivated at high temperature by the deposition of graphitic coke on their outer surface. Deactivation also occurred at low temperatures a result that the pores of the catalyst were blocked by polyaromatic compounds. The co-reaction of 13C-methanol and 12C-1-butene confirmed the importance of the acidity of the catalyst on the distribution of the hy-drocarbon products.

  5. Chemistry%化学

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    家自然科学基金(29706011)资助 O643 01050208 光电催化降解磺基水杨酸的研究=Study of Photoelectrocatalytic Degradation of Sulfosalicylic Acid[刊, 中]/刘鸿(中科院大连化学物理所),冷文华∥催化学报, 21(3).&209~212 建立了以TiO2/Ni为工作电极、泡沫镍为对电极、饱和甘汞电极为参比电极的光电催化反应体系,研究了在磺基水杨酸(SSal)的光电催化降解过程中,外加电压和溶液pH值对降解速率的影响.图5表1参18 国家自然科学基金(29877024)资助 O643 01050209 多孔TiO2薄膜的表面微结构对甲基橙光催化脱色的影响=Effect of Surface Microstructure of Porous TiO2 Thin Films on Photocatalytic Decolorization of Methyl Orange[刊, 中]/余家国(武汉工业大学),赵修建∥催化学报.&2000, 21(3).&213~216 湖北省自然科学基金资助 O643 01050210 γ-Mo2N催化剂上的乙炔选择加氢=Selective Hydrogenation of Ethyne on γ-Mo2N[刊, 中]/郝志显(中科院大连化学物理所),魏昭彬∥催化学报.&2000, 21(3).&217~220 对γ-Mo2N催化剂上乙炔加氢反应进行了研究.在150℃的反应温度下,乙炔转化率为95%,乙烯选择性达80%,乙烷选择性为4%,丁烯选择性为10%.反应温度和空速对产物的选择性没有明显的影响.图4参17 国家自然科学基金(29625305)资助 O643 01050211 WO3/ZrO2固体强酸催化剂上异丁烷/丁烯的烷基化反应:Ⅱ.过渡金属的助催化作用=Study on Alkylation of Isobutane with Butene over WO3/ZrO2 Strong Solid Acid:Ⅱ. Promotions Effect of Transition Metal[刊, 中]/孙闻东(中科院长春应用化学所),吴越∥催化学报.&2000, 21(3).&229~233 制备了一系列用过渡金属活化的WO3/ZrO2固体强酸催化剂,并对其晶型结构、表面状态和酸量进行了表征.图7表2参22 国家自然科学基金(29792076)资助 O212 01050212 超细镍基催化剂上CH4-CO2重整反应的性能:Ⅰ.制备方法对催化剂结构和还原性能的影响=CH4 Reforming with CO2 over