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Sample records for acetylene ethylene propane

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

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

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

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

    PubMed Central

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

    2015-01-01

    The removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene is a technologically very important, but highly challenging task. Current removal approaches include the partial hydrogenation over a noble metal catalyst and the solvent extraction of cracked olefins, both of which are cost and energy consumptive. Here we report a microporous metal–organic framework in which the suitable pore/cage spaces preferentially take up much more acetylene than ethylene while the functional amine groups on the pore/cage surfaces further enforce their interactions with acetylene molecules, leading to its superior performance for this separation. The single X-ray diffraction studies, temperature dependent gas sorption isotherms, simulated and experimental column breakthrough curves and molecular simulation studies collaboratively support the claim, underlying the potential of this material for the industrial usage of the removal of acetylene from ethylene/acetylene mixtures containing 1% acetylene at room temperature through the cost- and energy-efficient adsorption separation process. PMID:26041691

  3. Designing supported palladium-on-gold bimetallic nano-catalysts for controlled hydrogenation of acetylene in large excess of ethylene

    NASA Astrophysics Data System (ADS)

    Malla, Pavani

    Ethylene is used as a starting point for many chemical intermediates in the petrochemical industry. It is predominantly produced through steam cracking of higher hydrocarbons (ethane, propane, butane, naphtha, and gas oil). During the cracking process, a small amount of acetylene is produced as a side product. However, acetylene must be removed since it acts as a poison for ethylene polymerization catalysts at even ppm concentrations (>5 ppm). Thus, the selective hydrogenation of acetylene to ethylene is an important process for the purification of ethylene. Conventional, low weight loading Pd catalysts are used for this selective reaction in high concentration ethylene streams. Gold was initially considered to be catalytically inactive for a long time. This changed when gold was seen in the context of the nanometric scale, which has indeed shown it to have excellent catalytic activity as a homogeneous or a heterogeneous catalyst. Gold is proved to have high selectivity to ethylene but poor at conversion. Bimetallic Au and Pd catalysts have exhibited superior activity as compared to Pd particles in semi-hydrogenation. Hydrogenation of acetylene was tested using this bimetallic combination. The Pd-on-Au bimetallic catalyst structure provides a new synthesis approach in improving the catalytic properties of monometallic Pd materials. TiO 2 as a support material and 0.05%Pd loading on 1%Au on titania support and used different treatment methods like washing plasma and reduction between the two metal loadings and was observed under 2:1 ratio. In my study there were two set of catalysts which were prepared by a modified incipient wetness impregnation technique. Out of all the reaction condition the catalyst which was reduced after impregnating gold and then impregnating palladium which was further treated in non-thermal hydrogen plasma and then pretreated in hydrogen till 250°C for 1 hour produced the best activity of 76% yield at 225°C. Stability tests were conducted

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

    SciTech Connect

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

    1989-02-01

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

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

    SciTech Connect

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

    2007-06-28

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

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

    NASA Technical Reports Server (NTRS)

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

    2013-01-01

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

  7. Three-phase equilibria in the binary system ethylene + eicosane and the ternary system propane + ethylene + eicosane

    SciTech Connect

    Gregorowicz, J.; Loos, T.W. de; Arons, J. . Lab. of Applied Thermodyanamics and Phase Equilibria)

    1993-07-01

    The solid eicosane-liquid-vapor (SLV) phase behavior in the binary system ethylene + eicosane was investigated. It was found that the SLV curve ends at a critical end point where liquid and vapor are critical in the presence of pure solid eicosane. In this binary system liquid-liquid-vapor (LLV) equilibria are metastable with respect to solid formation. Addition of propane to mixtures of ethylene and eicosane revealed stable LLV equlibria. P-T sections for seven ternary mixtures with different propane and eicosane concentrations were determined according to the synthetic method. On the basis of the results obtained, a rough estimate of the ternary tricritical point and the metastable binary LLV curve is performed.

  8. A detailed kinetic modeling study of aromatics formation in laminar premixed acetylene and ethylene flames

    SciTech Connect

    Wang, H.; Frenklach, M.

    1997-07-01

    A computational study was performed for the formation and growth of polycyclic aromatic hydrocarbons (PAHs) in laminar premixed acetylene and ethylene flames. A new detailed reaction mechanism describing fuel pyrolysis and oxidation, benzene formation, and PAH mass growth and oxidation is presented and critically tested. It is shown that the reaction model predicts reasonably well the concentration profiles of major and intermediate species and aromatic molecules in a number of acetylene and ethylene flames reported in the literature. It is demonstrated that reactions of n-C{sub 4}H{sub x} + C{sub 2}H{sub 2} leading to the formation of one-ring aromatics are as important as the propargyl recombination, and hence must be included in kinetic modeling of PAH formation in hydrocarbon flames. It is further demonstrated that the mass growth of PAHs can be accounted for by the previously proposed H-abstraction-C{sub 2}H{sub 2}-addiction mechanism.

  9. Laboratory studies, analysis, and interpretation of the spectra of hydrocarbons present in planetary atmospheres including cyanoacetylene, acetylene, propane, and ethane

    NASA Technical Reports Server (NTRS)

    Blass, William E.; Daunt, Stephen J.; Peters, Antoni V.; Weber, Mark C.

    1990-01-01

    Combining broadband Fourier transform spectrometers (FTS) from the McMath facility at NSO and from NRC in Ottawa and narrow band TDL data from the laboratories with computational physics techniques has produced a broad range of results for the study of planetary atmospheres. Motivation for the effort flows from the Voyager/IRIS observations and the needs of Voyager analysis for laboratory results. In addition, anticipation of the Cassini mission adds incentive to pursue studies of observed and potentially observable constituents of planetary atmospheres. Current studies include cyanoacetylene, acetylene, propane, and ethane. Particular attention is devoted to cyanoacetylen (H3CN) which is observed in the atmosphere of Titan. The results of a high resolution infrared laboratory study of the line positions of the 663, 449, and 22.5/cm fundamental bands are presented. Line position, reproducible to better than 5 MHz for the first two bands, are available for infrared astrophysical searches. Intensity and broadening studies are in progress. Acetylene is a nearly ubiquitous atmospheric constituent of the outer planets and Titan due to the nature of methane photochemistry. Results of ambient temperature absolute intensity measurements are presented for the fundamental and two two-quantum hotband in the 730/cm region. Low temperature hotband intensity and linewidth measurements are planned.

  10. Heat of Combustion of the Product Formed by the Reaction of Acetylene, Ethylene, and Diborane

    NASA Technical Reports Server (NTRS)

    Tannenbaum, Stanley

    1957-01-01

    The net heat of combustion of the product formed by the reaction of diborane with a mixture of acetylene and ethylene was found to be 20,440 +/- 150 Btu per pound for the reaction of liquid fuel to gaseous carbon dioxide, gaseous water, and solid boric oxide. The measurements were made in a Parr oxygen-bomb calorimeter, and the combustion was believed to be 98 percent complete. The estimated net-heat of combustion for complete combustion would therefore be 20,850 +/- 150 Btu per pound.

  11. Nonphysiological binding of ethylene by plants.

    PubMed

    Abeles, F B

    1984-03-01

    Ethylene binding to seedling tissue of Vicia faba, Phaseolus vulgaris, Glycine max, and Triticum aestivum was demonstrated by determining transit time required for ethylene to move through a glass tube filled with seedling tissue. Transit time for ethylene was greater than that for methane indicating that these tissues had an affinity for ethylene. However, the following observations suggest that the binding was not physiological. Inhibitors of ethylene action such as Ag(+) ions and CO(2) did not decrease binding. Mushrooms which have no known sites of ethylene action also demonstrated ethylene binding. The binding of acetylene, propylene, ethylene, propane, and ethane more closely followed their solubility in water than any known physiological activity.

  12. Interactions between Lugol's fixative and ethylene in the acetylene-reduction assay for nitrogenase activity in lake water.

    PubMed

    Leonardson, L

    1980-05-01

    Lugol's solution is a practical and efficient fixative for the acetylene-reduction assay of nitrogenase activity in aquatic organisms. Correction must be made, however, for the solubility of ethylene in the liquid phase and reactions between Lugol's solution and ethylene. With a vapor phase-liquid phase volume ratio of 1.9:1, the mean solubility of ethylene in mixtures of lake water and Lugol's solution was 7.2%. No correlation was found between ethylene solubility and the concentration of Lugol's solution. Storage of fixed samples for more than 1 day before gas chromatographic analysis resulted in increased loss of ethylene from the vapor phase; the loss amounted to ca. 18% after 3 days. Higher losses were noted at higher concentrations of Lugol's solution. Most probably these effects were caused by iodine addition to ethylene, as indicated by the consumption of ethylene by iodine-potassium iodide solutions. The reaction was catalyzed by the rubber septa of the incubaton vessels when the septa were in contact with the liquid phase. Loss of ethylene decreased with increased concentration of phytoplankton because the organisms absorbed iodine. By using a standardized technique and determining ethylene solubility and reaction patterns between ethylene and the mixture of water and Lugol's solution, it is possible to correct for the loss of ethylene.

  13. Effect of Initial Mixture Temperature on Flame Speed of Methane-Air, Propane-Air, and Ethylene-Air Mixtures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L

    1952-01-01

    Flame speeds based on the outer edge of the shadow cast by the laminar Bunsen cone were determined as functions of composition for methane-air mixtures at initial mixture temperatures ranging from -132 degrees to 342 degrees c and for propane-air and ethylene-air mixtures at initial mixture temperatures ranging from -73 degrees to 344 degrees c. The data showed that maximum flame speed increased with temperature at an increasing rate. The percentage change in flame speed with change in initial temperature for the three fuels followed the decreasing order, methane, propane, and ethylene. Empirical equations were determined for maximum flame speed as a function of initial temperature over the temperature range covered for each fuel. The observed effect of temperature on flame speed for each of the fuels was reasonably well predicted by either the thermal theory as presented by Semenov or the square-root law of Tanford and Pease.

  14. Synergistic effect of mixing dimethyl ether with methane, ethane, propane, and ethylene fuels on polycyclic aromatic hydrocarbon and soot formation

    SciTech Connect

    Yoon, S.S.; Anh, D.H.; Chung, S.H.

    2008-08-15

    Characteristics of polycyclic aromatic hydrocarbon (PAH) and soot formation in counterflow diffusion flames of methane, ethane, propane, and ethylene fuels mixed with dimethyl ether (DME) have been investigated. Planar laser-induced incandescence and fluorescence techniques were employed to measure relative soot volume fractions and PAH concentrations, respectively. Results showed that even though DME is known to be a clean fuel in terms of soot formation, DME mixture with ethylene fuel increases PAH and soot formation significantly as compared to the pure ethylene case, while the mixture of DME with methane, ethane, and propane decreases PAH and soot formation. Numerical calculations adopting a detailed kinetics showed that DME can be decomposed to produce a relatively large number of methyl radicals in the low-temperature region where PAH forms and grows; thus the mixture of DME with ethylene increases CH{sub 3} radicals significantly in the PAH formation region. Considering that the increase in the concentration of O radicals is minimal in the PAH formation region with DME mixture, the enhancement of PAH and soot formation in the mixture flames of DME and ethylene can be explained based on the role of methyl radicals in PAH and soot formation. Methyl radicals can increase the concentration of propargyls, which could enhance incipient benzene ring formation through the propargyl recombination reaction and subsequent PAH growth. Thus, the result substantiates the importance of methyl radicals in PAH and soot formation, especially in the PAH formation region of diffusion flames. (author)

  15. Quantum Chemical Evaluation of the Astrochemical Significance of Reactions between S Atom and Acetylene or Ethylene

    NASA Technical Reports Server (NTRS)

    Woon, David E.

    2007-01-01

    Addition-elimination reactions of S atom in its P-3 ground state with acetylene (C2H2) and ethylene (C2H4) were characterized with both molecular orbital and density functional theory calculations employing correlation consistent basis sets in order to assess the likelihood either reaction might play a general role in astrochemistry or a specific role in the formation of S2 (X (sup 3 SIGMA (sub g) (sup -)) via a mechanism proposed by Saxena and Misra (Mon. Not. R. Astron. Soc. 1995, 272, 89). The acetylene and ethylene reactions proceed through C2H2S ((sup 3)A")) and C2H4S ((sup 3)A")) intermediates, respectively, to yield HCCS ((sup 2)II)) and C2H3S ((sup 2)A')). Substantial barriers were found in the exit channels for every combination of method and basis set considered in this work, which effectively precludes hydrogen elimination pathways for both S + C2H2 and S + C2H4 in the ultracold interstellar medium where only very modest barriers can be surmounted and processes without barriers tend to predominate. However, if one or both intermediates is formed and stabilized efficiently under cometary or dense interstellar cloud conditions, they could serve as temporary reservoirs for S atom and participate in reactions such as S + C2H2S (right arrow) S2 = C2H2 or S + C2H4S (right arrow) S2 + C2H4. For formation and stabilization to be efficient, the reaction must possess a barrier height small enough to be surmountable at low temperatures yet large enough to prevent redissociation to reactants. Barrier heights computed with B3LYP and large basis sets are very low, but more rigorous QCISD(T) and RCCSD(T) results indicate that the barrier heights are closer to 3-4 kcal/mol. The calculations therefore indicate that S + C2H2 or S + C2H4 could contribute to the formation of S2 in comets and may serve as a means to gauge coma temperature. The energetics of the ethylene reaction are more favorable.

  16. Quantum chemical evaluation of the astrochemical significance of reactions between S atom and acetylene or ethylene.

    PubMed

    Woon, David E

    2007-11-08

    Addition-elimination reactions of S atom in its 3P ground state with acetylene (C2H2) and ethylene (C2H4) were characterized with both molecular orbital and density functional theory calculations employing correlation consistent basis sets in order to assess the likelihood that either reaction might play a general role in astrochemistry or a specific role in the formation of S2 (X3Sigmag-) via a mechanism proposed by Saxena, P. P.; Misra, A. Mon. Not. R. Astron. Soc. 1995, 272, 89. The acetylene and ethylene reactions proceed through C2H2S (3A' ') and C2H4S (3A' ') intermediates, respectively, to yield HCCS (2Pi) and C2H3S (2A'). Substantial barriers were found in the exit channels for every combination of method and basis set considered in this work, which effectively precludes hydrogen elimination pathways for both S + C2H2 and S + C2H4 in the ultracold interstellar medium where only very modest barriers can be surmounted and processes without barriers tend to predominate. However, if one or both intermediates are formed and stabilized efficiently under cometary or dense interstellar cloud conditions, they could serve as temporary reservoirs for the S atom and participate in reactions such as S + C2H2S --> S2 + C2H2 or S + C2H4S --> S2 + C2H4. For formation and stabilization to be efficient, the reaction must possess a barrier height small enough to be surmountable at low temperatures yet large enough to prevent redissociation to reactants. Barrier heights computed with B3LYP and large basis sets are very low, but more rigorous QCISD(T) and RCCSD(T) results indicate that the barrier heights are closer to 3-4 kcal/mol. The calculations therefore indicate that S + C2H2 or S + C2H4 could contribute to the formation of S2 in comets and may serve as a means to gauge coma temperature. The energetics of the ethylene reaction are more favorable.

  17. Raman spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane for combustion applications

    NASA Astrophysics Data System (ADS)

    Magnotti, G.; KC, U.; Varghese, P. L.; Barlow, R. S.

    2015-09-01

    Spontaneous Raman scattering measurements of temperature and major species concentration in hydrocarbon-air flames require detailed knowledge of the Raman spectra of the hydrocarbons present when fuels more complex than methane are used. Although hydrocarbon spectra have been extensively studied at room temperature, there are no data available at higher temperatures. Quantum mechanical calculations, when available are not sufficiently accurate for combustion applications. This work presents experimental measurements of spontaneous Stokes-Raman scattering spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane in the temperature range 300-860 K. Raman spectra from heated hydrocarbons jets have been collected with a higher resolution than is generally employed for Raman measurements in combustion applications. A set of synthetic spectra have been generated for each hydrocarbon, providing the basis for extrapolation to higher temperatures. The spectra provided here will enable simultaneous measurements of multiple hydrocarbons in flames. This capability will greatly extend the range of applicability of Raman measurements in combustion applications. In addition, the experimental spectra provide a validation dataset for quantum mechanical models.

  18. Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene.

    PubMed

    Xiang, Sheng-Chang; Zhang, Zhangjing; Zhao, Cong-Gui; Hong, Kunlun; Zhao, Xuebo; Ding, De-Rong; Xie, Ming-Hua; Wu, Chuan-De; Das, Madhab C; Gill, Rachel; Thomas, K Mark; Chen, Banglin

    2011-02-22

    Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C(2)H(2)/C(2)H(4) have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C(2)H(2) and C(2)H(4). The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C(2)H(2)/C(2)H(4).

  19. A model for the ethylene and acetylene adsorption on the surface of Cun(n = 10-15) nanoclusters: A theoretical study

    NASA Astrophysics Data System (ADS)

    Farmanzadeh, Davood; Abdollahi, Tahereh

    2016-11-01

    In this work, we report the results of density functional theory calculations of ethylene and acetylene adsorption on the most stable Cun (n = 10-15) nanoclusters, in two π and di- σ adsorption modes. Both the hydrocarbons molecularly adsorbed on the surface. Our results show that the quality of interaction of ethylene and acetylene with odd copper nanoclusters (n = 11, 13, 15) is different from what is found on even copper nanoclusters (n = 10, 12, 14). One of the interesting features of this adsorption is that acetylene never orient toward di-σ mode for Cusbnd Cu bond in odd copper nanoclusters. Also, for di- σ-CunC2H4, no stable structure is identified. The highest interaction and deformation energies are seen for the adsorption of acetylene and ethylene on Cu11 in π-mode.

  20. DFT study of selective hydrogenation of acetylene to ethylene on Pd doping Ag nanoclusters

    NASA Astrophysics Data System (ADS)

    Liu, D.

    2016-11-01

    Recently, it has been reported that the reaction selectivity of catalytic hydrogenation of acetylene to ethylene can be significantly enhanced via the approach of Pd mono-atomic catalysis [Pei et al. ACS Catal. 5 (2015) 3717-3725]. To explain the catalytic mechanism of this binary alloy catalyst, C2H2 hydrogenation reactions on Pd doping Ag nanoclusters are studied using density functional theory simulations. The simulation results indicate that H2 and C2H2 can simultaneously bind with a single Pd doping atom no matter it is on vertex and edge sites of Ag clusters. The following H2 dissociation and C2H2 hydrogenation are not difficult since the corresponding reaction barrier values are no more than 0.58 eV. The generated C2H4 molecule can not be further hydrogenated since it locates on the top of Pd doping atom, which is the only adsorption site for H2. On two Pd doping atoms at contiguous sites of Ag clusters, C2H4 hydrogenation reactions can be carried out since there are enough sites for co-adsorption of H2 and C2H4.

  1. Successive lithiation of acetylene, ethylene and benzene: a comprehensive computational study of large static second hyperpolarizability.

    PubMed

    Mondal, Avijit; Hatua, Kaushik; Roy, Ria Sinha; Nandi, Prasanta K

    2017-02-08

    This work is a revisit of the study of the electron correlation effect of lithium substitution on the second hyperpolarizability (10(6) a.u.) of acetylene, ethylene and benzene. The large quenching of mean second hyperpolarizability has been addressed by CCSD calculations. The inclusion of triple excitation in the MP4 method generally overestimates second hyperpolarizability in comparison to the MP4SDQ method. The present CCSD γav value of C6Li6: 405 × 10(4) a.u. obtained with a relatively larger basis set established the earlier prediction of Sadlej et al. [Phys. Chem. Phys. Chem., 2000, 2, 3393-3399] where degenerate non-dipolar transitions in low lying excited states play the crucial role. The successive lithiation results in gradual red shifting of transition energy leading to significant enhancement of second hyperpolarizability. Most of the chosen DFT functionals predict the correct qualitative trend of second hyperpolarizability. The quantitatively different results may be attributed to the case when the ground state wave function cannot be approximated by a single SD.

  2. Prediction of electron and ion concentrations in low-pressure premixed acetylene and ethylene flames

    NASA Astrophysics Data System (ADS)

    Cancian, J.; Bennett, B. A. V.; Colket, M. B.; Smooke, M. D.

    2013-04-01

    Flame stabilisation and extinction in a number of different flows can be affected by application of electric fields. Electrons and ions are present in flames, and because of charge separation, weak electric fields can also be generated even when there is no externally applied electric field. In this work, a numerical model incorporating ambipolar diffusion and plasma kinetics has been developed to predict gas temperature, species, and ion and electron concentrations in laminar premixed flames without applied electric fields. This goal has been achieved by combining the existing CHEMKIN-based PREMIX code with a recently developed methodology for the solution of electron temperature and transport properties that uses a plasma kinetics model and a Boltzmann equation solver. A chemical reaction set has been compiled from seven sources and includes chemiionisation, ion-molecule, and dissociative-recombination reactions. The numerical results from the modified PREMIX code (such as peak number densities of positive ions) display good agreement with previously published experimental data for fuel-rich, non-sooting, low-pressure acetylene and ethylene flames without applied electric fields.

  3. The Effects of Supercritical Propane on the Alkylation of Toluene with Ethylene over USY and Sulfated Zirconia Catalysts

    SciTech Connect

    Ginosar, Daniel Michael; Burch, Kyle Coates; Thompson, David Neal

    2002-11-01

    The alkylation of toluene with ethylene over microporous USY zeolite and mesoporous sulfated zirconia (S/ZrO2) catalysts was explored at liquid, near-critical liquid, and supercritical conditions using propane as the supercritical cosolvent. Liquid, near-critical liquid, and supercritical conditions were examined for their effects on product selectivity and catalyst activity maintenance. The S/ZrO2 catalyst demonstrated alkylation activity almost exclusively, whereas the USY catalyst demonstrated both alkylation and cracking/disproportionation activities. Near-critical and supercritical reaction conditions improved product selectivity with the USY catalyst through the suppression of disproportionation reactions and enhanced ortho- and para-ethyltoluene selectivity. However, the addition of the supercritical cosolvent resulted in increased deactivation for both the S/ZrO2 and USY catalysts, with deactivation increasing with propane mole fraction.

  4. Flame Speeds of Methane-Air, Propane-Air, and Ethylene-Air Mixtures at Low Initial Temperatures

    NASA Technical Reports Server (NTRS)

    Dugger, Gordon L; Heimel, Sheldon

    1952-01-01

    Flame speeds were determined for methane-air, propane-air, and ethylene-air mixtures at -73 C and for methane-air mixtures at -132 C. The data extend the curves of maximum flame speed against initial mixture temperature previously established for the range from room temperature to 344 C. Empirical equations for maximum flame speed u(cm/ sec) as a function of initial mixture temperature T(sub O) were determined to be as follows: for methane, for T(sub O) from 141 to 615 K, u = 8 + 0.000160 T(sub O)(exp 2.11); for propane, for T(sub O) from 200 to 616 K, u = 10 + 0.000342 T(sub O)(exp 2.00); for ethylene, for T(sub O) from 200 to 617 K, u = 10 + 0.00259 T(sub O)(exp 1.74). Relative flame speeds at low initial temperatures were predicted within approximately 20 percent by either the thermal theory as presented by Semenov or by the diffusion theory of Tanford and Pease. The same order was found previously for high initial temperatures. The low-temperature data were also found to extend the linear correlations between maximum flame speed and calculated equilibrium active-radical concentrations, which were established by the previously reported high-temperature data.

  5. Differential solubility of ethylene and acetylene in room-temperature ionic liquids: a theoretical study.

    PubMed

    Zhao, Xu; Xing, Huabin; Yang, Qiwei; Li, Rulong; Su, Baogen; Bao, Zongbi; Yang, Yiwen; Ren, Qilong

    2012-04-05

    The room-temperature ionic liquids (RTILs) have potential in realizing the ethylene (C(2)H(4)) and acetylene (C(2)H(2)) separation and avoiding solvent loss and environmental pollution compared with traditional solvents. The interaction mechanisms between gases and RTILs are important for the exploration of new RTILs for gas separation; thus, they were studied by quantum chemical calculation and molecular dynamics simulation in this work. The optimized geometries were obtained for the complexes of C(2)H(4)/C(2)H(2) with anions (Tf(2)N(-), BF(4)(-), and OAc(-)), cation (bmim(+)), and their ion pairs, and the analysis for geometry, interaction energy, natural bond orbital (NBO), and atoms in molecules (AIM) was performed. The quantum chemical calculation results show that the hydrogen-bonding interaction between the gas molecule and anion is the dominant factor in determining the solubility of C(2)H(2) in RTILs. However, the hydrogen-bonding interaction, the p-π interaction in C(2)H(4)-anion, and the π-π interaction in C(2)H(4)-cation are weak and comparable, which all affect the solubility of C(2)H(4) in RTILs with comparable contribution. The calculated results for the distance of H(gas)···X (X = O or F in anions), the BSSE-corrected interaction energy, the electron density of H(gas)···X at the bond critical point (ρ(BCP)), and the relative second-order perturbation stabilization energy (E(2)) are consistent with the experimental data that C(2)H(2) is more soluble than C(2)H(4) in the same RTILs and the solubility of C(2)H(4) in RTILs has the following order: [bmim][Tf(2)N] > [bmim][OAc] > [bmim][BF(4)]. The calculated results also agree with the order of C(2)H(2) solubility in different RTILs that [bmim][OAc] > [bmim][BF(4)] > [bmim][Tf(2)N]. Furthermore, the calculation results indicate that there is strong C(2)H(2)-RTIL interaction, which cannot be negligible compared to the RTIL-RTIL interaction; thus, the regular solution theory is probably not

  6. Rationally tuned micropores within enantiopure metal-organic frameworks for highly selective separation of acetylene and ethylene

    SciTech Connect

    Xiang, Sheng-Chang; Zhang, Zhangjing; Zhao, Cong-Gui; Hong, Kunlun; Zhao, Xuebo; Ding, De-Rong; Xie, Ming-Hua; Wu, Chuan-De; Madhab, Das; Gill, Rachel; Thomas, K Mark; Chen, Banglin

    2011-01-01

    Separation of acetylene and ethylene is an important industrial process because both compounds are essential reagents for a range of chemical products and materials. Current separation approaches include the partial hydrogenation of acetylene into ethylene over a supported Pd catalyst, and the extraction of cracked olefins using an organic solvent; both routes are costly and energy consuming. Adsorption technologies may allow separation, but microporous materials exhibiting highly selective adsorption of C{sub 2}H{sub 2}/C{sub 2}H{sub 4} have not been realized to date. Here, we report the development of tunable microporous enantiopure mixed-metal-organic framework (M'MOF) materials for highly selective separation of C{sub 2}H{sub 2} and C{sub 2}H{sub 4}. The high selectivities achieved suggest the potential application of microporous M'MOFs for practical adsorption-based separation of C{sub 2}H{sub 2}/C{sub 2}H{sub 4}.

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

    PubMed

    Lomond, Jasmine S; Tong, Anthony Z

    2011-01-01

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

  8. Reactions of 1-Naphthyl Radicals with Acetylene. Single-Pulse Shock Tube Experiments and Quantum Chemical Calculations. Differences and Similarities in the Reaction with Ethylene

    NASA Astrophysics Data System (ADS)

    Lifshitz, Assa; Tamburu, Carmen; Dubnikova, Faina

    2009-09-01

    The reactions of 1-naphthyl radicals with acetylene were studied behind reflected shock waves in a single-pulse shock tube, covering the temperature range 950-1200 K at overall densities behind the reflected shocks of ˜2.5 × 10-5 mol/cm3. 1-Iodonaphthalene served as the source for 1-naphthyl radicals. The [acetylene]/[1-iodonaphthalene] ratio in all of the experiments was ˜100 to channel the free radicals into reactions with acetylene rather than iodonaphthalene. Only two major products resulting from the reactions of 1-naphthyl radicals with acetylene and with hydrogen atoms were found in the post shock samples. They were acenaphthylene and naphthalene. Some low molecular weight aliphatic products at rather low concentrations, resulting from an attack of various free radicals on acetylene, were also found in the shocked samples. In view of the relatively low temperatures employed in the present experiments, the unimolecular decomposition rate of acetylene is negligible. One potential energy surface describes the production of acenaphthylene and 1-naphthyl acetylene, although the latter was not found experimentally due to the high barrier (calculated) required for its production. Using quantum chemical methods, the rate constants for three unimolecular elementary steps on the surface were calculated using transition state theory. A kinetics scheme containing 16 elementary steps was constructed, and computer modeling was performed. An excellent agreement between the experimental yields of the two major products and the calculated yields was obtained. Differences and similarities in the potential energy surfaces of 1-naphthyl radical + acetylene and those of ethylene are presented, and the kinetics mechanisms are discussed.

  9. Vertical and meridional distribution of ethane, acetylene and propane in Saturn’s stratosphere from CIRS/Cassini limb observations

    NASA Astrophysics Data System (ADS)

    Guerlet, Sandrine; Fouchet, Thierry; Bézard, Bruno; Simon-Miller, Amy A.; Michael Flasar, F.

    2009-09-01

    Measuring the spatial distribution of chemical compounds in Saturn's stratosphere is critical to better understand the planet's photochemistry and dynamics. Here we present an analysis of infrared spectra in the range 600-1400 cm -1 acquired in limb geometry by the Cassini spacecraft between March 2005 and January 2008. We first determine the vertical temperature profiles from 3 to 0.01 hPa, at latitudes ranging from 70°N to 80°S. We infer a similar meridional temperature gradient at 1-2 hPa as in recent previous studies [Fletcher, L.N., Irwin, P.G.J., Teanby, N.A., Orton, G.S., Parrish, P.D., de Kok, R., Howett, C., Calcutt, S.B., Bowles, N., Taylor, F.W., 2007. Icarus 189, 457-478; Howett, C.J.A., Irwin, P.G.J., Teanby, N.A., Simon-Miller, A., Calcutt, S.B., Fletcher, L.N., de Kok, R., 2007. Icarus 190, 556-572]. We then retrieve the vertical profiles of C2H6 and C2H2 from 3 to 0.01 hPa and of C3H8 around 1 hPa. At 1 hPa, the meridional variation of C2H2 is found to follow the yearly averaged solar insolation, except for a strong equatorial mole fraction of 8×10-7, nearly two times higher than expected. This enhancement in abundance can be explained by the descent of hydrocarbon-rich air, with a vertical wind speed at the equator of 0.25±0.1 mm/s at 1 hPa and 0.4±0.15 mm/s at 0.1 hPa. The ethane distribution is relatively uniform at 1 hPa, with only a moderate 25% increase from 35°S to 80°S. Propane is found to increase from north to south by a factor of 1.9, suggesting that its lifetime may be shorter than Saturn's year at 1 hPa. At high altitudes (1 Pa), C2H2 and C2H6 abundances depart significantly from the photochemical model predictions of Moses and Greathouse [Moses, J.I., Greathouse, T.K., 2005. J. Geophys. Res. 110, 9007], except at high southern latitudes (62, 70 and 80°S) and near the equator. The observed abundances are found strongly depleted in the 20-40°S region and enhanced in the 20-30°N region, the latter coinciding with the ring

  10. Heterolytic Activation of C-H Bonds on Cr(III)-O Surface Sites Is a Key Step in Catalytic Polymerization of Ethylene and Dehydrogenation of Propane.

    PubMed

    Conley, Matthew P; Delley, Murielle F; Núñez-Zarur, Francisco; Comas-Vives, Aleix; Copéret, Christophe

    2015-06-01

    We describe the reactivity of well-defined chromium silicates toward ethylene and propane. The initial motivation for this study was to obtain a molecular understanding of the Phillips polymerization catalyst. The Phillips catalyst contains reduced chromium sites on silica and catalyzes the polymerization of ethylene without activators or a preformed Cr-C bond. Cr(II) sites are commonly proposed active sites in this catalyst. We synthesized and characterized well-defined chromium(II) silicates and found that these materials, slightly contaminated with a minor amount of Cr(III) sites, have poor polymerization activity and few active sites. In contrast, chromium(III) silicates have 1 order of magnitude higher activity. The chromium(III) silicates initiate polymerization by the activation of a C-H bond of ethylene. Density functional theory analysis of this process showed that the C-H bond activation step is heterolytic and corresponds to a σ-bond metathesis type process. The same well-defined chromium(III) silicate catalyzes the dehydrogenation of propane at elevated temperatures with activities similar to those of a related industrial chromium-based catalyst. This reaction also involves a key heterolytic C-H bond activation step similar to that described for ethylene but with a significantly higher energy barrier. The higher energy barrier is consistent with the higher pKa of the C-H bond in propane compared to the C-H bond in ethylene. In both cases, the rate-determining step is the heterolytic C-H bond activation.

  11. Shape and optical properties of aerosols formed by photolysis of acetylene, ethylene, and hydrogen cyanide

    NASA Astrophysics Data System (ADS)

    Bar-Nun, A.; Kleinfeld, I.; Ganor, E.

    1988-07-01

    The shapes and sizes of photochemically produced aerosol particles of polyacetylene, polyethylene, and polyhydrogen cyanide were studied experimentally. All of the single particles were found to be perfectly spherical and semiliquid. However, they aggregate readily, with a sticking coefficient near unity, to form nonspherical particles, which could give rise to the observed polarization from Titan's and Jupiter's upper haze layers. The absorbance of polyacetylene was remeasured and corrected, and it is now much closer to that of polyethylene. The measured real and imaginary indices of refraction of the two materials make them both suitable material for Titan's and Jupiter's upper haze layers. However, the larger abundance and higher rate of polymerization of acetylene would make it the dominant aerosol-forming material in both atmospheres.

  12. Shape and optical properties of aerosols formed by photolysis of acetylene, ethylene, and hydrogen cyanide

    SciTech Connect

    Bar-Nun, A.; Kleinfeld, I.; Ganor, E.

    1988-07-20

    The shapes and sizes of photochemically produced aerosol particles of polyacetylene, polyethylene, and polyhydrogen cyanide were studied experimentally. All of the single particles were found to be perfectly spherical and semiliquid. However, they aggregate readily, with a sticking coefficient near unity, to form nonspherical particles, which could give rise to the observed polarization from Titan's and Jupiter's upper haze layers. The absorbance of polyacetylene was remeasured and corrected, and it is now much closer to that of polyethylene. The measured real and imaginary indices of refraction of the two materials make them both suitable material for Titan's and Jupiter's upper haze layers. However, the larger abundance and higher rate of polymerization of acetylene would make it the dominant aerosol-forming material in both atmospheres. copyright American Geophysical Union 1988

  13. Temperature and pressure dependence of the absolute rate constant for the reactions of NH2 radicals with acetylene and ethylene

    NASA Technical Reports Server (NTRS)

    Bosco, S. R.; Nava, D. F.; Brobst, W. D.; Stief, L. J.

    1984-01-01

    The absolute rate constants for the reaction between the NH2 free radical and acetylene and ethylene is measured experimentally using a flash photolysis technique. The constant is considered to be a function of temperature and pressure. At each temperature level of the experiment, the observed pseudo-first-order rate constants were assumed to be independent of flash intensity. The results of the experiment indicate that the bimolecular rate constant for the NH2 + C2H2 reaction increases with pressure at 373 K and 459 K but not at lower temperatures. Results near the pressure limit conform to an Arrhenius expression of 1.11 (+ or -) 0.36 x 10 to the -13th over the temperature range from 241 to 459 K. For the reaction NH2 + C2H4, a smaller rate of increase in the bimolecular rate constant was observed over the temperature range 250-465 K. The implications of these results for current theoretical models of NH2 + C2H2 (or H4) reactions in the atmospheres of Jupiter and Saturn are discussed.

  14. A model of ethylene and acetylene adsorption on the (111) surfaces of platinum and nickel

    NASA Astrophysics Data System (ADS)

    Felter, T. E.; Weinberg, W. H.

    1981-02-01

    Despite the application of a variety of surface sensitive techniques to the adsorption of simple hydrocarbons on well characterized metallic surfaces, no consistent picture has appeared. We review briefly the published spectroscopic results of ultraviolet photoelectron spectroscopy (UPS) and electron energy loss spectroscopy (EELS) which probe, respectively, the electronic and vibrational structure of the surface-molecular complex, and we consider appropriate free molecular analogues, not only in their ground state but also in their first excited states. A simplified approach to determine the chemisorption geometry from UPS level shifts and EELS is presented. The technique allows an isolation of distortion induced shifts from the total relaxation shift, and we find that the true relaxation shift is rather constant, approximately 2.1 eV for the cases considered. These shifts can then be used to estimate the distance of the molecule to the surface. We concentrate primarily on four systems, C 2H 2 and C 2H 4 on Ni(111) and Pt(111), adsorbed at low temperature (below the onset of dissociation). Depending on the metal, the hydrocarbon can adsorb in a di-σ arrangement or with a distortion resembling the lowest energy configuration of the first excited state of the free molecule. We also consider briefly C 2H 4 on Ag and Cu in which no distortion occurs. The distortions that resemble the first excited states might occur as a consequence of donation of bonding (backbonding) electrons from (to) the normally filled π (empty π ∗) to (from) the empty (filled) d-band states of the metal. The net effect on the hydrocarbon to partially empty the π level and fill the π ∗ level, is analogous to a low excitation of the free molecule, π → π ∗. For C 2H 4 (planar in the ground state), the lowest excitation is the triplet T-state (3-4 eV) of minimal energy for a 90° twisted configuration with a lengthened C-C bond. Acetylene is a linear molecule in the ground state, but

  15. In situ spectroscopic characterization of Ni1-xZnx/ZnO catalysts and their selectivity for acetylene semihydrogenation in excess ethylene

    SciTech Connect

    Spanjers, Charles S.; Sim, Richard S.; Sturgis, Nicholas P.; Kabius, Bernd; Rioux, Robert M.

    2015-10-30

    The structures of ZnO-supported Ni catalysts were explored with in situ X-ray absorption spectroscopy, temperature-programmed reduction, X-ray diffraction, high-resolution transmission electron microscopy (HRTEM), scanning transmission electron microscopy, and electron energy loss spectroscopy. Calcination of nickel nitrate on a nanoparticulate ZnO support at 450 °C results in the formation of Zn-doped NiO (ca. N₀̣̣₈₅ Zn₀̣̣₁₅O) nanoparticles with the rock salt crystal structure. Subsequent in situ reduction monitored by X-ray absorption near-edge structure (XANES) at the Ni K edge reveals a direct transformation of the Zn-doped NiO nanoparticles to a face-centered cubic alloy, Ni1-xZnx, at ~400 °C with x increasing with increasing temperature. Both in situ XANES and ex situ HRTEM provide evidence for intermetallic β₁-NiZn formation at ~550 °C. In comparison to a Ni/SiO₂ catalyst, Ni/ZnO necessitates a higher temperature for the reduction of NiII to Ni⁰, which highlights the strong interaction between Ni and the ZnO support. The catalytic activity for acetylene removal from an ethylene feed stream is decreased by a factor of 20 on Ni/ZnO in comparison to Ni/SiO₂. The decrease in catalytic activity of Ni/ZnO is accompanied by a reduced absolute selectivity to ethylene. H–D exchange measurements demonstrate a reduced ability of Ni/ZnO to dissociate hydrogen in comparison to Ni/SiO₂.These results of the catalytic experiments suggest that the catalytic properties are controlled, in part, by the zinc oxide support and stress the importance of reporting absolute ethylene selectivity for the catalytic semihydrogenation of acetylene in excess ethylene.

  16. The ALMA-PILS survey: First detections of ethylene oxide, acetone and propanal toward the low-mass protostar IRAS 16293-2422

    NASA Astrophysics Data System (ADS)

    Lykke, J. M.; Coutens, A.; Jørgensen, J. K.; van der Wiel, M. H. D.; Garrod, R. T.; Müller, H. S. P.; Bjerkeli, P.; Bourke, T. L.; Calcutt, H.; Drozdovskaya, M. N.; Favre, C.; Fayolle, E. C.; Jacobsen, S. K.; Öberg, K. I.; Persson, M. V.; van Dishoeck, E. F.; Wampfler, S. F.

    2017-01-01

    Context. One of the open questions in astrochemistry is how complex organic and prebiotic molecules are formed. The unsurpassed sensitivity of the Atacama Large Millimeter/submillimeter Array (ALMA) takes the quest for discovering molecules in the warm and dense gas surrounding young stars to the next level. Aims: Our aim is to start the process of compiling an inventory of oxygen-bearing complex organic molecules toward the solar-type Class 0 protostellar binary IRAS 16293-2422 from an unbiased spectral survey with ALMA, Protostellar Interferometric Line Survey (PILS). Here we focus on the new detections of ethylene oxide (c-C2H4O), acetone (CH3COCH3), and propanal (C2H5CHO). Methods: With ALMA, we surveyed the spectral range from 329 to 363 GHz at 0.5″ (60 AU diameter) resolution. Using a simple model for the molecular emission in local thermodynamical equilibrium, the excitation temperatures and column densities of each species were constrained. Results: We successfully detect propanal (44 lines), ethylene oxide (20 lines) and acetone (186 lines) toward one component of the protostellar binary, IRAS 16293B. The high resolution maps demonstrate that the emission for all investigated species originates from the compact central region close to the protostar. This, along with a derived common excitation temperature of Tex ≈ 125 K, is consistent with a coexistence of these molecules in the same gas. Conclusions: The observations mark the first detections of acetone, propanal and ethylene oxide toward a low-mass protostar. The relative abundance ratios of the two sets of isomers, a CH3COCH3/C2H5CHO ratio of 8 and a CH3CHO/c-C2H4O ratio of 12, are comparable to previous observations toward high-mass protostars. The majority of observed abundance ratios from these results as well as those measured toward high-mass protostars are up to an order of magnitude above the predictions from chemical models. This may reflect either missing reactions or uncertain rates in the

  17. High-performance liquid chromatography separation of small molecules on a porous poly (trimethylol propane triacrylate-co-N-isopropylacrylamide-co-ethylene dimethacrylate) monolithic column.

    PubMed

    Liu, Haiyan; Bai, Xiaomei; Wei, Dan; Yang, Gengliang

    2014-01-10

    A porous monolith was prepared by in situ free-radical polymerization using N-isopropylacrylamide (NIPAAm) and trimethylol propane triacrylate (TMPTA) as functional monomers, ethylene dimethacrylate (EDMA) as crosslinking agent. The chemical group of the monolith was assayed by a Fourier transform infrared spectroscopy (FT-IR) method and the morphology of optimized monolithic column was characterized by scanning electron microscopy (SEM). The mechanical strength and permeability have been studied in detail as well. The run-to-run and column-to-column reproducibility of the retention times were less than 0.9% and 3.0%, respectively. Furthermore, the influence of temperature and mobile phase composition on the separation of aromatic compounds was investigated. The results indicated that poly (trimethylol propane triacrylate-co-N-isopropylacrylamide-co-ethylenedimethacrylate) (TMPTA-co-NIPAAm-co-EDMA) monolithic column not only had high porosity and strong rigidity, but also was a promising tool for analyzing small molecule compounds with a short analysis time by controlling the column temperature.

  18. Thinking out of the black box: accurate barrier heights of 1,3-dipolar cycloadditions of ozone with acetylene and ethylene.

    PubMed

    Wheeler, Steven E; Ess, Daniel H; Houk, K N

    2008-02-28

    Accurate barriers for the 1,3-dipolar cycloadditions of ozone with acetylene and ethylene have been determined via the systematic extrapolation of ab initio energies within the focal point approach of Allen and co-workers. Electron correlation has been accounted for primarily via coupled cluster theory, including single, double, and triple excitations, as well as a perturbative treatment of connected quadruple excitations [CCSD, CCSD(T), CCSDT, and CCSDT(Q)]. For the concerted [4 + 2] cycloadditions, the final recommended barriers are DeltaH(0K) = 9.4 +/- 0.2 and 5.3 +/- 0.2 kcal mol(-1) for ozone adding to acetylene and ethylene, respectively. These agree with recent results of Cremer et al. and Anglada et al., respectively. The reaction energy for O3 + C2H2 exhibits a protracted convergence with respect to inclusion of electron correlation, with the CCSDT/cc-pVDZ and CCSDT(Q)/cc-pVDZ values differing by 2.3 kcal mol-1. Recommended enthalpies of formation (298 K) for cycloadducts 1,2,3-trioxole and 1,2,3-trioxolane are +32.8 and -1.6 kcal mol(-1), respectively. Popular composite ab initio approaches [CBS-QB3, CBS-APNO, G3, G3B3, G3(MP2)B3, G4, G4(MP3), and G4(MP2)] predict a range of barrier heights for these systems. The CBS-QB3 computed barrier for ozone and acetylene, DeltaH(0K) = 4.4 kcal mol(-1), deviates by 5 kcal mol(-1) from the focal point value. CBS-QB3 similarly underestimates the barrier for the reaction of ozone and ethylene, yielding a prediction of only 0.7 kcal mol(-1). The errors in the CBS-QB3 results are significantly larger than mean errors observed in application to the G2 test set. The problem is traced to the nontransferability of MP2 basis set effects in the case of these reaction barriers. The recently published G4 and G4(MP2) approaches perform substantially better for O3 + C2H2, predicting enthalpy barriers of 9.0 and 8.4 kcal mol(-1), respectively. For the prediction of these reaction barriers, the additive corrections applied in the

  19. Propane Basics

    SciTech Connect

    NREL

    2010-03-01

    Propane powers about 190,000 vehicles in the U.S. and more than 14 million worldwide. Propane vehicles are a good choice for many fleet applications including school buses, shuttle buses, taxies and light-duty trucks.

  20. Propane Update.

    ERIC Educational Resources Information Center

    Brantner, Max

    1984-01-01

    Reports on a northern Illinois school bus fleet converted to propane fuel in 1981 and 1982. Includes tables showing, first, total annual fuel costs before and after conversion and, second, fuel efficiency for 16 buses using propane and three using gasoline. Notes precautions for propane use. (MCG)

  1. Preparation of a novel porous poly (trimethylol propane triacrylate-co-ethylene dimethacrylate) monolithic column for highly efficient HPLC separations of small molecules.

    PubMed

    Bai, Xiaomei; Liu, Haiyan; Wei, Dan; Yang, Gengliang

    2014-02-01

    A novel poly (trimethylol propane triacrylate-co-ethylene dimethacrylate) [poly (TMPTA-co-EDMA)] monolith was prepared by in situ free-radical polymerization in a 50 mm × 4.6mm i.d. stainless steel column and was investigated for high performance liquid chromatography (HPLC). The porous structure of monolith was optimized by changing the conditions of polymerization. The chemical group of the monolithic column was confirmed by a Fourier transform infrared spectroscopy (FT-IR) method and the morphology of column structure was characterized by scanning electron microscopy (SEM). The mechanical strength and permeability were also studied. Finally, a series of low-molecular-weight organic compounds were utilized to evaluate the retention behaviors of the monolithic column. The result demonstrated that the prepared column exhibited an RP-chromatographic behavior and good separation performance. The method reproducibility was obtained by evaluating the run-to-run and column-to-column with relative standard deviations (RSDs) less than 0.7% (n=6) and 2.9% (n=6), respectively, which indicated that prepared monolithic columns had good reproducibility and stability.

  2. Triel Bonds, π-Hole-π-Electrons Interactions in Complexes of Boron and Aluminium Trihalides and Trihydrides with Acetylene and Ethylene.

    PubMed

    Grabowski, Sławomir J

    2015-06-19

    MP2/aug-cc-pVTZ calculations were performed on complexes of aluminium and boron trihydrides and trihalides with acetylene and ethylene. These complexes are linked through triel bonds where the triel center (B or Al) is characterized by the Lewis acid properties through its π-hole region while π-electrons of C2H2 or C2H4 molecule play the role of the Lewis base. Some of these interactions possess characteristics of covalent bonds, i.e., the Al-π-electrons links as well as the interaction in the BH3-C2H2 complex. The triel-π-electrons interactions are classified sometimes as the 3c-2e bonds. In the case of boron trihydrides, these interactions are often the preliminary stages of the hydroboration reaction. The Quantum Theory of "Atoms in Molecules" as well as the Natural Bond Orbitals approach are applied here to characterize the π-hole-π-electrons interactions.

  3. A photochemical study of the kinetics of the reactions of NH2 with phosphine, ethylene, and acetylene using flash photolysis-laser induced fluorescence. Ph.D. Thesis Catholic Univ. of America; [ammonia in the atmosphere of Jupiter

    NASA Technical Reports Server (NTRS)

    Bosco, S. R.

    1982-01-01

    The photochemistry of the reactions of NH2 was investigated in an attempt to explain the existence of an abundance of ammonia in the Jovian atmosphere. The production of ammonia reservoirs from the coupling of ammonia with other atmospheric constituents was considered. The rate constants for the reactions of NH2 radicals with phosphine, acetylene, and ethylene were measured. Flash photolysis was used for the production of NH2 radicals and laser induced fluorescence was employed for radical detection. It was determined that the rates of the reactions were too slow to be significant as a source of ammonia reservoirs in the Jovian atmosphere.

  4. Theoretical and Laboratory Studies on the Interaction of Cosmic-Ray Particles with Interstellar Ices. III. Suprathermal Chemistry-Induced Formation of Hydrocarbon Molecules in Solid Methane (CH4), Ethylene (C2H4), and Acetylene (C2H2)

    NASA Astrophysics Data System (ADS)

    Kaiser, R. I.; Roessler, K.

    1998-08-01

    Methane, ethylene, and acetylene ices are irradiated in a ultra high vacuum vessel at 10 K with 9.0 MeV α-particles and 7.3 MeV protons to elucidate mechanisms to form hydrocarbon molecules upon interaction of Galactic cosmic-ray particles with extraterrestrial, organic ices. Theoretical calculations focus on computer simulations of ion-induced collision cascades in irradiated targets. Our experimental and computational investigations reveal that each MeV particle transfers its kinetic energy predominantly through inelastic encounters to the target leading to electronic excitation and ionization of the target molecules. Here electronically excited CH4 species can fragment to mobile H atoms and nonmobile CH3 radicals. The potential energy stored in Coulomb interaction of the CH+4 ions release energetic H and C atoms not in thermal equilibrium with the 10 K target (suprathermal species). Moderated to 1-10 eV kinetic energy, these carbon atoms and those triggered by the elastic energy transfer of the MeV projectile to the target are found to abstract up to two H atoms to yield suprathermal CH and CH2 species. C and CH, as well as CH2, can insert into a CH bond of a CH4 molecule to form methylcarbene (HCCH3), the ethyl radical (C2H5), and ethane (C2H6). HCCH3 either loses H2/2H to form acetylene, C2H2, rearranges to ethylene, C2H4, or adds two H atoms to form ethane, C2H6. C2H5 can abstract or lose an H atom, giving ethane and ethylene, respectively. C2H2 and C2H4 are found to react with suprathermal H atoms to form C2H3 and C2H5, respectively. Overlapping cascades and an increasing MeV ion exposure transforms C2Hx (x = 2, ..., 6) to even more complex alkanes up to C14H30. These elementary reactions of suprathermal species to insert, abstract, and add in/to bonds supply a powerful pathway to form new molecules in icy grain mantles condensed on interstellar grains or in hydrocarbon rich bodies in our solar system even at temperatures as low as 10 K.

  5. Reaction Mechanism of the Symmetry-Forbidden [2+2] Addition of Ethylene and Acetylene to Amido-Substituted Digermynes and Distannynes Ph2N-EE-NPh2, (E = Ge, Sn): A Theoretical Study.

    PubMed

    Zhao, Lili; Jones, Cameron; Frenking, Gernot

    2015-08-24

    Quantum chemical calculations of reaction mechanisms for the formal [2+2] addition of ethylene and acetylene to the amido-substituted digermyne and distannyne Ph2N-EE-NPh2 (E = Ge, Sn) have been carried out by using density functional theory at the BP86/def2-TZVPP level. The nature and bonding situations were studied with the NBO method and with the charge and energy decomposition analysis EDA-NOCV. The addition of ethylene to Ph2N-EE-NPh2 takes place through an initial [2+1] addition to one metal atom and consecutive rearrangement to four-membered cyclic species, which feature a weak E-E bond. Rotation about the C-C bond with concomitant rupture of the E-E bond leads to the 1,2-disubstituted ethanes, which have terminal E(NPh2) groups. The overall reaction Ph2N-EE-NPh2+C2H4→(Ph2N)E-C2H4-E(NPh2) has very low activation barriers and is slightly exergonic for E = Ge but slightly endergonic for E = Sn. The analysis of the electronic structure shows that there is charge donation of nearly one electron to the ethylene moiety already in the first part of the reaction. The energy partitioning analysis suggests that the HOMO(Ph2N-EE-NPh2)→LUMO(C2H4) interaction has a similar strength as the HOMO(C2H4)→LUMO(Ph2N-EE-NPh2) interaction. The [2+2] addition of acetylene to Ph2N-EE-NPh2 also takes place through an initial [2+1] approach, which eventually leads to 1,2-disubstituted olefins (Ph2N)E-C2H2-E(NPh2). The formation of the energetically lowest lying conformations of cis-(Ph2N)E-C2H2-E(NPh2), which occurs with very low activation barriers, is clearly exergonic for the germanium and the tin compound. The trans-coordinated isomers of (Ph2N)E-C2H2-E(NPh2) are slightly lower in energy than the cis form but they are separated by a substantial energy barrier for the rotation about the C-C bond. The energy decomposition analysis indicates that the initial reaction takes place under formation of electron-sharing bonds between triplet fragments rather than HOMO

  6. Enhancing aerobic biodegradation of 1,2-dibromoethane in groundwater using ethane or propane and inorganic nutrients

    NASA Astrophysics Data System (ADS)

    Hatzinger, Paul B.; Streger, Sheryl H.; Begley, James F.

    2015-01-01

    1,2-Dibromoethane (ethylene dibromide; EDB) is a probable human carcinogen that was previously used as both a soil fumigant and a scavenger in leaded gasoline. EDB has been observed to persist in soils and groundwater, particularly under oxic conditions. The objective of this study was to evaluate options to enhance the aerobic degradation of EDB in groundwater, with a particular focus on possible in situ remediation strategies. Propane gas and ethane gas were observed to significantly stimulate the biodegradation of EDB in microcosms constructed with aquifer solids and groundwater from the FS-12 EDB plume at Joint Base Cape Cod (Cape Cod, MA), but only after inorganic nutrients were added. Ethene gas was also effective, but rates were appreciably slower than for ethane and propane. EDB was reduced to < 0.02 μg/L, the Massachusetts state Maximum Contaminant Level (MCL), in microcosms that received ethane gas and inorganic nutrients. An enrichment culture (BE-3R) that grew on ethane or propane gas but not EDB was obtained from the site materials. The degradation of EDB by this culture was inhibited by acetylene gas, suggesting that degradation is catalyzed by a monooxygenase enzyme. The BE-3R culture was also observed to biodegrade 1,2-dichloroethane (DCA), a compound commonly used in conjunction with EDB as a lead scavenger in gasoline. The data suggest that addition of ethane or propane gas with inorganic nutrients may be a viable option to enhance degradation of EDB in groundwater aquifers to below current state or federal MCL values.

  7. Growth of Nocardia rhodochrous on acetylene gas.

    PubMed Central

    Kanner, D; Bartha, R

    1979-01-01

    Soil sediment enrichment cultures yielded a coryneform bacterium capable of growing in a mineral salts solution with acetylene gas as its only source of carbon and energy. Based on morphological and physiological traits as well as on cell wall analysis, the bacterium was characterized as a strain of Nocardia rhodochrous. Maximal growth rates (generation time 2.7 to 3.0 h) on acetylene were obtained at 5 to 20% acetylene, 25 to 40% oxygen, pH 7.0 and 26 to 28 degrees C. Yields (grams of dry cells produced per gram of acetylene consumed) ranged between 90 and 110%. N. rhodochrous exhibits a growth factor requirement for the pyrimidine moiety of thiamine. Acetylene utilization is not an obligate trait, and a wide range of alternate carbon sources is utilized. Ethylene is neither produced nor consumed. The only previous report on acetylene utilization appeared in 1932. The Mycobacterium lacticola strain described in that report strongly resembles N. rhodochrous. PMID:37235

  8. Proton exchange membrane fuel cell cathode contamination - Acetylene

    NASA Astrophysics Data System (ADS)

    Zhai, Y.; St-Pierre, Jean

    2015-04-01

    Acetylene adsorption on PEMFC electrodes and contamination in single cells are investigated with 300 ppm acetylene at a cathode held at 80 °C. The results of adsorption experiments suggest that acetylene adsorbs readily on electrodes and is reduced to ethylene and ethane under an open circuit potential of H2/N2, as the adsorbates can be electro-oxidized at high potentials. The cell voltage response shows that 300 ppm acetylene results in a cell performance loss of approximately 88%. The voltage degradation curve is divided into two stages by an inflection point, which suggests that potential-dependent processes are involved in acetylene poisoning. These potential-dependent processes may include acetylene oxidation and reduction as well as accumulation of intermediates on the electrode surface. Electrochemical impedance spectroscopy analysis suggests that acetylene affects the oxygen reduction reaction and may also affect mass transport processes. Acetylene also may be reduced in the steady poisoning state of the operating cell. After neat air operation, the cyclic voltammetry results imply that the cathode catalyst surface is almost completely restored, with no contaminant residues remaining in the MEA. Linear scanning voltammetry measurements show no change in hydrogen crossover caused by contamination, and polarization curves confirm complete recovery of cell performance.

  9. Acetylenic carbon allotrope

    DOEpatents

    Lagow, Richard J.

    1998-01-01

    A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

  10. Acetylenic carbon allotrope

    DOEpatents

    Lagow, Richard J.

    1999-01-01

    A fourth allotrope of carbon, an acetylenic carbon allotrope, is described. The acetylenic carbon allotropes of the present invention are more soluble than the other known carbon allotropes in many common organic solvents and possesses other desirable characteristics, e.g. high electron density, ability to burn cleanly, and electrical conductive properties. Many uses for this fourth allotrope are described herein.

  11. Propane Vehicle Demonstration Grant Program

    SciTech Connect

    Jack Mallinger

    2004-08-27

    Project Description: Propane Vehicle Demonstration Grants The Propane Vehicle Demonstration Grants was established to demonstrate the benefits of new propane equipment. The US Department of Energy, the Propane Education & Research Council (PERC) and the Propane Vehicle Council (PVC) partnered in this program. The project impacted ten different states, 179 vehicles, and 15 new propane fueling facilities. Based on estimates provided, this project generated a minimum of 1,441,000 new gallons of propane sold for the vehicle market annually. Additionally, two new off-road engines were brought to the market. Projects originally funded under this project were the City of Portland, Colorado, Kansas City, Impco Technologies, Jasper Engines, Maricopa County, New Jersey State, Port of Houston, Salt Lake City Newspaper, Suburban Propane, Mutual Liquid Propane and Ted Johnson.

  12. Processing of polyolefin blends in supercritical propane solution

    NASA Astrophysics Data System (ADS)

    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

  13. Acetylene terminated matrix resins

    NASA Technical Reports Server (NTRS)

    Goldfarb, I. J.; Lee, Y. C.; Arnold, F. E.; Helminiak, T. E.

    1985-01-01

    The synthesis of resins with terminal acetylene groups has provided a promising technology to yield high performance structural materials. Because these resins cure through an addition reaction, no volatile by-products are produced during the processing. The cured products have high thermal stability and good properties retention after exposure to humidity. Resins with a wide variety of different chemical structures between the terminal acetylene groups are synthesized and their mechanical properties studied. The ability of the acetylene cured polymers to give good mechanical properties is demonstrated by the resins with quinoxaline structures. Processibility of these resins can be manipulated by varying the chain length between the acetylene groups or by blending in different amounts of reactive deluents. Processing conditions similar to the state-of-the-art epoxy can be attained by using backbone structures like ether-sulfone or bis-phenol-A. The wide range of mechanical properties and processing conditions attainable by this class of resins should allow them to be used in a wide variety of applications.

  14. Acylamidation of acetylenes

    SciTech Connect

    Gridnev, I.D.; Balenkova, E.S.

    1989-01-10

    The reactions of phenylacetylene, 1-heptyne, and diphenylacetylene with the complexes of acetylfluoroborate with acetonitrile and with chloroacetonitrile take place regiospecifically and stereospecifically as syn-addition of the acetyl group and nitrile at the triple bond of the acetylene and lead to previously unknown Z-N-acyl-/beta/-amino, /alpha/,/beta/-unsaturated ketones.

  15. Titan's Propane from Cassini Infrared Spectroscopy

    NASA Astrophysics Data System (ADS)

    Nixon, C. A.; Jennings, D. E.; Flaud, J.-M.; Bezard, B.; Teanby, N. A.; Irwin, P. G. J.; Ansty, T. M.; Coustenis, A.; Flasar, F. M.

    2009-04-01

    Propane gas (C3H8) was first detected in the atmosphere of Titan by the Voyager 1 IRIS spectrometer, during the 1980 encounter (Maguire et al., 1981), and remains the heaviest saturated hydrocarbon (alkane) found there to date. Although the identification was based on the detection of several bands (including 748, 922, 1054, 1158 cm-1), only the ν26 band at 748 cm-1 has been subsequently modeled to retrieve the abundance, due to the unique availability of its line parameters in the GEISA database (Husson et al. 1992). Subsequent measurements from the ground (Roe et al., 2003) and Earth-orbit (ISO - Coustenis et al. 2003) have also focused on this one band, deriving an abundance of ~0.5 ppm, although it remains compromised by coincidence with the R-branch of the much stronger acetylene (C2H2) gas. The Composite Infrared Spectrometer (CIRS) instrument carried on-board the Cassini spacecraft in Saturn orbit has now been observing Titan during more than 50 flybys over 5 years, and offers a fresh perspective on the prevalence of propane. With much improved spectral and spatial resolution and sensitivity over IRIS, CIRS is also able to perform repeated limb sounding (viewing through the atmosphere above the surface) to increase signal-to-noise still further. Modeling and removal of the emissions of other gases now shows clearly for the first time a multitude of propane bands: including the four seen by IRIS and at least four others (869, 1338, 1376, 1472 cm-1). In addition, a new line atlas for three bands of propane at shorter wavelengths (1300-1500 cm-1) has now been compiled, based on the work of Flaud et al. (2001). With this, we now have the potential to model these weaker bands, and to check the measurements made by CIRS using the 748 cm-1 band alone. Preliminary analysis has shown that the retrievals are very sensitive to the spectral baseline (haze model) assumed, and that existing lab tholin spectral properties (Khare et al. 1984) do not well match the opacity

  16. Propane-d6 Heterogeneously Hyperpolarized by Parahydrogen

    PubMed Central

    2015-01-01

    Long-lived spin states of hyperpolarized propane-d6 gas were demonstrated following pairwise addition of parahydrogen gas to propene-d6 using heterogeneous parahydrogen-induced polarization (HET-PHIP). Hyperpolarized molecules were synthesized using Rh/TiO2 solid catalyst with 1.6 nm Rh nanoparticles. Hyperpolarized (PH ∼ 1%) propane-d6 was detected at high magnetic field (9.4 T) spectroscopically and by high-resolution 3D gradient-echo MRI (4.7 T) as the gas flowed through the radiofrequency coil with a spatial and temporal resolution of 0.5 × 0.5 × 0.5 mm3 and 17.7 s, respectively. Stopped-flow hyperpolarized propane-d6 gas was also detected at 0.0475 T with an observed nuclear spin polarization of PH ∼ 0.1% and a relatively long lifetime with T1,eff = 6.0 ± 0.3 s. Importantly, it was shown that the hyperpolarized protons of the deuterated product obtained via pairwise parahydrogen addition could be detected directly at low magnetic field. Importantly, the relatively long low-field T1,eff of HP propane-d6 gas is not susceptible to paramagnetic impurities as tested by exposure to ∼0.2 atm oxygen. This long lifetime and nontoxic nature of propane gas could be useful for bioimaging applications including potentially pulmonary low-field MRI. The feasibility of high-resolution low-field 2D gradient-echo MRI was demonstrated with 0.88 × 0.88 mm2 spatial and ∼0.7 s temporal resolution, respectively, at 0.0475 T. PMID:25506406

  17. Ethylene update

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gaseous plant hormone ethylene is required for many aspects of plant growth, development and responses to the environment. Potato tubers produce low amounts of ethylene and are highly sensitive to ethylene in the atmosphere. Several responses of potato tubers to endogenous and exogenous ethylene...

  18. Nitrogen fixation (acetylene reduction) by epiphytes of freshwater macrophytes.

    PubMed

    Finke, L R; Seeley, H W

    1978-07-01

    The involvement of epiphytic microorganisms in nitrogen fixation was investigated in a shallow freshwater pond near Ithaca, N.Y. The acetylene reduction technique was used to follow diel and seasonal cycles of nitrogen fixation by epiphytes of Myriophyllum spicatum. Acetylene-reducing activity was maximal between noon and 6 p.m., but substantial levels of activity relative to daytime rates continued through the night. Experiments with the seasonal course of activity showed a gradual decline during the autumn months and no activity in January or February. Activity commenced in May, with an abrupt increase to levels between 0.45 and 0.95 nmol of ethylene formed per mg (dry weight) of plant per h. Through most of the summer months, mean rates of acetylene reduction remained between 0.15 and 0.60 nmol/mg (dry weight) per h. It was calculated from diel and seasonal cycles that, in the pond areas studied, epiphytes were capable of adding from 7.5 to 12.5 mug of N per mg of plant per year to the pond. This amount is significant relative to the total amount of nitrogen incorporated into the plant. Blue-green algae (cyanobacteria), particularly Gloeotrichia, appeared to bear prime responsibility for nitrogen fixation, but photosynthetic bacteria of the genus Rhodopseudomonas were isolated from M. spicatum and shown to support high rates of acetylene reduction.

  19. Acetylene on Titan

    NASA Astrophysics Data System (ADS)

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

    2016-10-01

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

  20. Costs Associated With Propane Vehicle Fueling Infrastructure

    SciTech Connect

    Smith, M.; Gonzales, J.

    2014-08-05

    This document is designed to help fleets understand the cost factors associated with propane vehicle fueling infrastructure. It provides an overview of the equipment and processes necessary to develop a propane fueling station and offers estimated cost ranges.

  1. Costs Associated With Propane Vehicle Fueling Infrastructure

    SciTech Connect

    Smith, M.; Gonzales, J.

    2014-08-01

    This document is designed to help fleets understand the cost factors associated with propane vehicle fueling infrastructure. It provides an overview of the equipment and processes necessary to develop a propane fueling station and offers estimated cost ranges.

  2. Application of the photoacoustic method to the measurement of acetylene reduction by nitrogenase enzyme

    NASA Astrophysics Data System (ADS)

    Schramm, D. U.; Sthel, M. S.; Carneiro, L. O.; Franco, A. A.; Campos, A. C.; Vargas, H.

    2005-06-01

    Nitrogenase is an enzyme responsible for the reduction of the atmospheric N2 into NH4^+, which represents the key entry point of the molecular nitrogen into the biogeochemical cycle of nitrogen. This enzyme is present in the rhizobial bacteroids, which are symbionts in a Leguminosae plant (Acacia Holosericea), and also reduces acetylene into ethylene at the same rate as the nitrogen reduction. Therefore, a CO2 Laser Photoacoustic system was used for detecting and monitoring the ethylene emission by the nitrogenase activity, in the rhizobial symbionts in Acacia Holosericea, when they are confined in test tubes with acetylene at two different volumes (0.1 and 0.5 ml). Ethylene concentrations are also determined in the ppm range.

  3. Safety design in the Noretyl I/S ethylene plant, Norway

    SciTech Connect

    Boeckmann, T.; Ingebrigtsen, G.H.; Haekstad, T.; Noretyl, I.

    1980-01-01

    The plant, with capacity for 300,000 tons/yr of ethylene and 70,000 tons/yr of propylene was started up in 1977. It was designed and constructed by Linde A.G. for Noretyle (which is owned 51% by Norsk Hydro A/S, 33% by Norske Stats Oljeselskap A/S, and 16% by Sega Petrokjemi A/S and Co.) according to the requirements of a new national code of safety for oil refineries and petrochemical plants in Norway, jointly developed by Linde, Norsk Hydro, and the Norwegian authorities. Detailed discussions are presented for the safety aspects of plant layout; the location of important buildings: noise limitation and explosion prevention in the compression buildings; remote isolation and venting for pipework or vessels leaking hydrocarbons; blowdown and flare system connected to equipment safety valves; gas detectors; the shutdown system for the acetylene hydrogenation reactor; pneumatic instrumentation for the plant; a high signal-level electronic system for shutdown and alarms; the fire protection system in the tankage area; the shutdown system for the underground propane-storage cavern; and procedures for coping with the human aspects of plant hazards.

  4. Measurement of position-specific 13C isotopic composition of propane at the nanomole level

    NASA Astrophysics Data System (ADS)

    Gilbert, Alexis; Yamada, Keita; Suda, Konomi; Ueno, Yuichiro; Yoshida, Naohiro

    2016-03-01

    We have developed a novel method for analyzing intramolecular carbon isotopic distribution of propane as a potential new tracer of its origin. The method is based on on-line pyrolysis of propane followed by analysis of carbon isotope ratios of the pyrolytic products methane, ethylene and ethane. Using propane samples spiked with 13C at the terminal methyl carbon, we characterize the origin of the pyrolytic fragments. We show that the exchange between C-atoms during the pyrolytic process is negligible, and thus that relative intramolecular isotope composition can be calculated. Preliminary data from 3 samples show that site-preference (SP) values, defined as the difference of δ13C values between terminal and sub-terminal C-atom positions of propane, range from -1.8‰ to -12.9‰. In addition, SP value obtained using our method for a thermogenic natural gas sample is consistent with that expected from theoretical models of thermal cracking, suggesting that the isotope fractionation associated with propane pyrolysis is negligible. The method will provide novel insights into the characterization of the origin of propane and will help better understand the biogeochemistry of natural gas deposits.

  5. Research in acetylene containing monomers

    NASA Technical Reports Server (NTRS)

    Ogliaruso, M. A.

    1976-01-01

    The preparation of precursor bisbenzils with pendant acetylene linkages for use in the synthesis of new aromatic poly (phenyl quinoxalines) was investigated. Attempts to condense para, para prime-dibromo benzil and potassium acetylide in liquid ammonia and in toluene, to prepare 4-phenyl acetyl phenyl ether, 4-(paraacetylphenyl) acetyl phenyl ether, 4-phenyl acetyl-4 primeacetyl phenyl acetyl phenyl ether, the reaction of 4-phenyl acetyl phenyl ether with Villsmeier reagent to prepare 4-(beta-chloro cinnamaldehyde) phenyl ether, the reaction of 4-(para-acetyl phenyl) acetyl phenyl ether with Villsmeier reagent, and the oxidation of bibenzil to prepare benzil are described. The reactions of phenyl acetylene with oxidizing agent, of phenyl acetylene with bromine, of 1,1,2,2-tetrabromo ethyl benzene with zinc and with oxidizing agent are described.

  6. 41 CFR 50-204.66 - Acetylene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 41 Public Contracts and Property Management 1 2010-07-01 2010-07-01 true Acetylene. 50-204.66..., Vapors, Fumes, Dusts, and Mists § 50-204.66 Acetylene. (a) The in-plant transfer, handling, storage, and utilization of acetylene in cylinders shall be in accordance with Compressed Gas Association Pamphlet...

  7. 29 CFR 1910.102 - Acetylene.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 5 2010-07-01 2010-07-01 false Acetylene. 1910.102 Section 1910.102 Labor Regulations... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.102 Acetylene. (a) Cylinders. Employers must ensure that the in-plant transfer, handling, storage, and use of acetylene in cylinders...

  8. 29 CFR 1910.102 - Acetylene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... may comply with the provisions of Chapter 7 (“Acetylene Piping”) of NFPA 51A-2001 (“Standard for... comply with the provisions of NFPA 51A-2006 (“Standard for Acetylene Charging Plants”) (National Fire... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.102 Acetylene. (a) Cylinders....

  9. 29 CFR 1910.102 - Acetylene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... may comply with the provisions of Chapter 7 (“Acetylene Piping”) of NFPA 51A-2001 (“Standard for... comply with the provisions of NFPA 51A-2006 (“Standard for Acetylene Charging Plants”) (National Fire... OCCUPATIONAL SAFETY AND HEALTH STANDARDS Hazardous Materials § 1910.102 Acetylene. (a) Cylinders....

  10. The adaptive control system of acetylene generator

    NASA Astrophysics Data System (ADS)

    Kovaliuk, D. O.; Kovaliuk, Oleg; Burlibay, Aron; Gromaszek, Konrad

    2015-12-01

    The method of acetylene production in acetylene generator was analyzed. It was found that impossible to provide the desired process characteristics by the PID-controller. The adaptive control system of acetylene generator was developed. The proposed system combines the classic controller and fuzzy subsystem for controller parameters tuning.

  11. Electron ionization of acetylene.

    PubMed

    King, Simon J; Price, Stephen D

    2007-11-07

    Relative partial ionization cross sections and precursor specific relative partial ionization cross sections for fragment ions formed by electron ionization of C2H2 have been measured using time-of-flight mass spectrometry coupled with a 2D ion-ion coincidence technique. We report data for the formation of H+, H+2, C2+, C+/C2+ 2, CH+/C2H+2, CH+2, C+2, and C2H+ relative to the formation of C2H+2, as a function of ionizing electron energy from 30-200 eV. While excellent agreement is found between our data and one set of previously published absolute partial ionization cross sections, some discrepancies exist between the results presented here and two other recent determinations of these absolute partial ionization cross sections. We attribute these differences to the loss of some translationally energetic fragment ions in these earlier studies. Our relative precursor-specific partial ionization cross sections enable us, for the first time, to quantify the contribution to the yield of each fragment ion from single, double, and triple ionization. Analysis shows that at 50 eV double ionization contributes 2% to the total ion yield, increasing to over 10% at an ionizing energy of 100 eV. From our ion-ion coincidence data, we have derived branching ratios for charge separating dissociations of the acetylene dication. Comparison of our data to recent ab initio/RRKM calculations suggest that close to the double ionization potential C2H2+2 dissociates predominantly on the ground triplet potential energy surface (3Sigma*g) with a much smaller contribution from dissociation via the lowest singlet potential energy surface (1Delta g). Measurements of the kinetic energy released in the fragmentation reactions of C2H2+2 have been used to obtain precursor state energies for the formation of product ion pairs, and are shown to be in good agreement with available experimental data and with theory.

  12. Silane-propane ignitor/burner

    DOEpatents

    Hill, Richard W.; Skinner, Dewey F.; Thorsness, Charles B.

    1985-01-01

    A silane propane burner for an underground coal gasification process which is used to ignite the coal and to controllably retract the injection point by cutting the injection pipe. A narrow tube with a burner tip is positioned in the injection pipe through which an oxidant (oxygen or air) is flowed. A charge of silane followed by a supply of fuel, such as propane, is flowed through the tube. The silane spontaneously ignites on contact with oxygen and burns the propane fuel.

  13. Silane-propane ignitor/burner

    DOEpatents

    Hill, R.W.; Skinner, D.F. Jr.; Thorsness, C.B.

    1983-05-26

    A silane propane burner for an underground coal gasification process which is used to ignite the coal and to controllably retract the injection point by cutting the injection pipe. A narrow tube with a burner tip is positioned in the injection pipe through which an oxidant (oxygen or air) is flowed. A charge of silane followed by a supply of fuel, such as propane, is flowed through the tube. The silane spontaneously ignites on contact with oxygen and burns the propane fuel.

  14. The cytochrome P-450 active site. Regiospecificity of prosthetic heme alkylation by olefins and acetylenes.

    PubMed

    Kunze, K L; Mangold, B L; Wheeler, C; Beilan, H S; Ortiz de Montellano, P R

    1983-04-10

    Hepatic microsomal cytochrome P-450 from phenobarbital-pretreated rats is inactivated during the metabolism of linear olefins (ethylene, propene, and octene) and acetylenes (acetylene, propyne, and octyne). As expected from previous work, the inactivation is due to N-alkylation of the prosthetic heme group by the substrate. The N-alkyl group in each adduct is formally obtained by addition of a porphyrin nitrogen to the terminal carbon and of an oxygen atom (as a hydroxyl function) to the internal carbon of the pi-bond. The oxygen is shown here by 18O studies to be catalytically introduced by the enzyme. The olefins exclusively alkylate the nitrogen of pyrrole ring D, but the acetylenes alkylate that of pyrrole ring A. Acetylene is an exception in that it reacts with more than one nitrogen. Circular dichroism studies of the ethylene adduct and of the ring D regioisomer of N-ethylprotoporphyrin IX obtained by alkylation of the prosthetic heme of hemoglobin have been used to determine which face of cytochrome P-450 heme is alkylated by the unsaturated substrates. These results implicate an active site that is sterically encumbered in the region over pyrrole ring B and has a lipophilic binding site that accommodates chains of at least six carbon atoms over pyrrole ring C.

  15. Acetylene-terminated polyimide adhesives

    NASA Technical Reports Server (NTRS)

    Hanky, A. O.

    1983-01-01

    The nadic-encapped LARC-13 addition polyimide exhibits excellent flow, is easy to process, and can be utilized for short terms at temperatures up to 593 C. It retains good lap shear strength as an adhesive for titanium after aging in air up to 125 hours at 316 C; but lap shear strength degrades with longer exposures at that temperature. Thermid 600, an addition polyimide that is acetylene encapped, exhibits thermomechanical properties even after long term exposure in at air at 316 C. An inherent drawback of this system is that it has a narrow processing window. An acetylene encapped, addition polyimide which is a hybrid of these two systems was developed. It has good retention of strength after long term aging and is easily processed. The synthesis and characterization of various molecular weight oligomers of this system are discussed as well as the bonding, aging, and testing of lap shear adhesive samples.

  16. Thermal Conversion of Methane to Acetylene

    SciTech Connect

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

    2000-01-01

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

  17. 76 FR 75782 - Revising Standards Referenced in the Acetylene Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-05

    ... the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Department of... is revising its Acetylene Standard for general industry by updating a reference to a standard... and Explanation of Revisions to the Acetylene Standard IV. Procedural Determinations A....

  18. Acetylene terminated aspartimides and resins therefrom

    NASA Technical Reports Server (NTRS)

    Hergenrother, Paul M. (Inventor); Connell, John W. (Inventor); Havens, Stephen J. (Inventor)

    1989-01-01

    Acetylene terminated aspartimides are prepared using two methods. In the first, an amino-substituted aromatic acetylene is reacted with an aromatic bismaleimide in a solvent of glacial acetic acid and/or m-cresol. In the second method, an aromatic diamine is reacted with an ethynyl containing maleimide, such an N-(3-ethynyl phenyl) maleimide, in a solvent of glacial acetic acid and/or m-cresol. In addition, acetylene terminated aspartimides are blended with various acetylene terminated oligomers and polymers to yield composite materials exhibiting improved mechanical properties.

  19. Cometabolic biodegradation of 1,2,3-trichloropropane by propane-oxidizing bacteria.

    PubMed

    Wang, Baixin; Chu, Kung-Hui

    2017-02-01

    1,2,3-Trichloropropane (TCP) is an emerging groundwater pollutant and suspected human carcinogen. TCP, a recalcitrant contaminant, has been detected in the subsurface near TCP manufacture facilities and many superfund sites. Considering the toxicity and the occurence of TCP, there is a need to seek for cost-effective treatment technologies for TCP-contaminated sites. This paper investigated TCP biodegradation by propane-oxidizing bacteria (PrOB) which are known to express propane monooxygenase (PrMO). PrMO can cometabolically degrade many different contaminants. Four PrOB, Rhodococus jostii RHA1, Mycobacterium vaccae JOB5, Rhodococcus rubber ENV425 and one isolate Sphingopyxis sp. AX-A were examined for their ability to degrade TCP. All the four PrOB resting cells were able to degrade TCP. Strain JOB5 exhibited the best TCP degradation ability (vinitial = 9.7 ± 0.7 μg TCP (mg protein)(-1)h(-1)). No TCP was degraded in the presence of acetylene (an inhibitor for PrMO), suggesting that PrMO might be responsible for TCP degradation. Furthermore, competitive inhibition was observed between propane and TCP, and between trichloroethylene (TCE) and TCP.

  20. Propane vehicles : status, challenges, and opportunities.

    SciTech Connect

    Rood Werpy, M.; Burnham, A.; Bertram, K.; Energy Systems

    2010-06-17

    Propane as an auto fuel has a high octane value and has key properties required for spark-ignited internal combustion engines. To operate a vehicle on propane as either a dedicated fuel or bi-fuel (i.e., switching between gasoline and propane) vehicle, only a few modifications must be made to the engine. Until recently propane vehicles have commonly used a vapor pressure system that was somewhat similar to a carburetion system, wherein the propane would be vaporized and mixed with combustion air in the intake plenum of the engine. This leads to lower efficiency as more air, rather than fuel, is inducted into the cylinder for combustion (Myers 2009). A newer liquid injection system has become available that injects propane directly into the cylinder, resulting in no mixing penalty because air is not diluted with the gaseous fuel in the intake manifold. Use of a direct propane injection system will improve engine efficiency (Gupta 2009). Other systems include the sequential multi-port fuel injection system and a bi-fuel 'hybrid' sequential propane injection system. Carbureted systems remain in use but mostly for non-road applications. In the United States a closed-loop system is used in after-market conversions. This system incorporates an electronic sensor that provides constant feedback to the fuel controller to allow it to measure precisely the proper air/fuel ratio. A complete conversion system includes a fuel controller, pressure regulator valves, fuel injectors, electronics, fuel tank, and software. A slight power loss is expected in conversion to a vapor pressure system, but power can still be optimized with vehicle modifications of such items as the air/fuel mixture and compression ratios. Cold start issues are eliminated for vapor pressure systems since the air/fuel mixture is gaseous. In light-duty propane vehicles, the fuel tank is typically mounted in the trunk; for medium- and heavy-duty vans and trucks, the tank is located under the body of the vehicle

  1. 41 CFR 50-204.66 - Acetylene.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 41 Public Contracts and Property Management 1 2014-07-01 2014-07-01 false Acetylene. 50-204.66 Section 50-204.66 Public Contracts and Property Management Other Provisions Relating to Public Contracts.... (b) The piped systems for the in-plant transfer and distribution of acetylene shall be...

  2. 41 CFR 50-204.66 - Acetylene.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 41 Public Contracts and Property Management 1 2012-07-01 2009-07-01 true Acetylene. 50-204.66 Section 50-204.66 Public Contracts and Property Management Other Provisions Relating to Public Contracts.... (b) The piped systems for the in-plant transfer and distribution of acetylene shall be...

  3. 46 CFR 147.70 - Acetylene.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Acetylene. 147.70 Section 147.70 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DANGEROUS CARGOES HAZARDOUS SHIPS' STORES Stowage and Other Special Requirements for Particular Materials § 147.70 Acetylene. (a) Seventeen cubic meters (600...

  4. 29 CFR 1910.102 - Acetylene.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... with the provisions of CGA Pamphlet G-1-2003 (“Acetylene”) (Compressed Gas Association, Inc., 11th ed..., 2006, these employers may comply with the provisions of Chapter 7 (“Acetylene Piping”) of NFPA 51A-2001 (“Standard for Acetylene Charging Plants”) (National Fire Protection Association, 2001 ed., 2001). (3)...

  5. Theoretical study of the bonding of the first-row transition-metal positive ions to ethylene

    NASA Technical Reports Server (NTRS)

    Sodupe, M.; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.; Partridge, Harry

    1992-01-01

    Ab initio calculations were performed to study the bonding of the first-row transition-metal ions with ethylene. While Sc(+) and Ti(+) insert into the pi bond of ethylene to form a three-membered ring, the ions V(+) through Cu(+) form an electrostatic complex with ethylene. The binding energies are compared with those from experiment and with those of comparable calculations performed previously for the metal-acetylene ion systems.

  6. Ethylene glycol

    Integrated Risk Information System (IRIS)

    Ethylene glycol ; CASRN 107 - 21 - 1 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic E

  7. Ethylene diamine

    Integrated Risk Information System (IRIS)

    Ethylene diamine ; CASRN 107 - 15 - 3 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarcinogenic

  8. [The gas chromatographic detection of acetylene in cadaveric material].

    PubMed

    Iablochkin, V D

    1999-01-01

    Acetylene traces were detected by gas chromatography in the cadaveric right crural muscle of a 30-year-old man dead from an explosion of an acetylene reservoir at a plant. Acetylene was identified using the absolute calibration method on 3 standard gas chromatographic columns, reaction gas chromatography, and acetylene "deduction" by silver sulfate on silicagel.

  9. Acetylene measurement in flames by chirp-based quantum cascade laser spectrometry.

    PubMed

    Quine, Zachary R; McNesby, Kevin L

    2009-06-01

    We have designed and characterized a mid-IR spectrometer built around a pulsed distributed-feedback quantum cascade laser using the characteristic frequency down-chirp to scan through the spectral region 6.5 cm(-1) spectral region. The behavior of this chirp is extensively measured. The accuracy and detection limits of the system as an absorption spectrometer are demonstrated first by measuring spectra of acetylene through a single pass 16 cm absorption cell in real time at low concentrations and atmospheric pressure. The smallest detectable peak is measured to be approximately 1.5 x 10(-4) absorbance units, yielding a minimum detectable concentration length product of 2.4 parts per million meter at standard temperature and pressure. This system is then used to detect acetylene within an ethylene-air opposed flow flame. Measurements of acetylene content as a function of height above the fuel source are presented, as well as measurements of acetylene produced in fuel breakdown as a function of preinjection fuel temperature.

  10. Incorporation of deuterium in coke formed on an acetylene hydrogenation catalyst

    SciTech Connect

    Larsson, M.; Jansson, J.; Asplund, S.

    1996-09-01

    In selective hydrogenation of acetylene in excess ethylene, considerable amounts of coke or {open_quotes}green oils{close_quotes} are formed and accumulate on the catalyst. A fraction of the acetylene undergoes oligomerization reactions producing C{sub 4}`s and larger hydrocarbons. Compounds larger than C{sub 8} are retained on the catalysts surface or as a condensed phase in the pore system. The reaction mechanism is largely unknown but several authors have postulated that oligomerization occurs through dissociatively adsorbed acetylene (2), i.e., C{sub 2}H(ads) and C{sub 2}(ads). In this paper a novel method of studying the coke formation on a catalyst is introduced. Deuterium is incorporated in the coke during hydrogenation of acetylene, and during temperature-programmed oxidation (TPO) experiments the deuterium content is analyzed. The objective is to shed some light on the mechanism for oligomer formation in this system. The catalyst, Pd/{alpha}-Al{sub 2}O{sub 3}, was prepared by the impregnation of {alpha}-alumina (Sued-Chemie) with a solution of Pd(NO{sub 3}){sub 2} in 30% HNO{sub 3}. 8 refs., 4 figs.

  11. 75 FR 14131 - Effect on Propane Consumers of the Propane Education and Research Council's Operations, Market...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-03-24

    ..., agricultural, process and nonfuel users of propane. This notice of inquiry is part of an effort to collect information to fulfill requirements under the Propane Education and Research Act of 1996 that established PERC...., Suite 4053, Washington, DC 20230. FOR FURTHER INFORMATION CONTACT: For questions on the submission...

  12. An unnatural death by propan-1-ol and propan-2-ol.

    PubMed

    Skopp, Gisela; Gutmann, Isabelle; Schwarz, Clara-Sophie; Schmitt, Georg

    2016-07-01

    A fatality of an inpatient ingesting a disinfectant containing ethanol, propan-1-ol, and propan-2-ol is reported. The alleged survival time was about 1 h. Major findings at autopsy were an extended hemorrhagic lung edema, an edematous brain, and shock kidneys. Concentrations of alcohols and acetone, a major metabolite of propan-2-ol, were determined from body fluids (blood from the heart and the femoral vein, urine, gastric contents) and tissues (brain, muscle, liver, kidneys, lungs) by headspace/gas chromatography using 2-methylpropan-2-ol as the internal standard. All samples investigated were positive for propan-1-ol, propan-2-ol, ethanol, and acetone except stomach contents, where acetone was not detectable. The low concentration of acetone compared to propan-2-ol likely supports the short survival time. The concentration ratios estimated from the results are in accordance with the physico-chemical properties of the particular alcohols, their different affinities towards alcohol dehydrogenase as well as their interdependence during biotransformation. Autopsy did not reveal the cause of death. According to the few published data, blood concentrations of 1.44 and 1.70 mg/g of propan-2-ol and propan-1-ol, respectively, are considered sufficient to have caused the death. This case also points to the need to restrict access to antiseptic solutions containing alcohols in wards with patients at risk.

  13. Oligomers Terminated By Maleimide And Acetylene

    NASA Technical Reports Server (NTRS)

    St. Clair, Terry L.; Pater, Ruth H.; Gerber, Margaret K.

    1994-01-01

    Oligomeric molecules terminated with maleimide and acetylene groups synthesized and thermally treated to form cross-linked polymers exhibiting high or undetectable glass-transition temperatures and high thermo-oxidative stabilities. Compounds used to make thermally stable, glassy polymers.

  14. RMP Guidance for Propane Storage Facilities - Main Text

    EPA Pesticide Factsheets

    This document is intended as comprehensive Risk Management Program guidance for larger propane storage or distribution facilities who already comply with propane industry standards. Includes sample RMP, and release calculations.

  15. Ethylene glycol blood test

    MedlinePlus

    ... this page: //medlineplus.gov/ency/article/003564.htm Ethylene glycol blood test To use the sharing features ... enable JavaScript. This test measures the level of ethylene glycol in the blood. Ethylene glycol is a ...

  16. . . . While Others Conserve Cash by Converting from Gasoline to Propane.

    ERIC Educational Resources Information Center

    Rasmussen, Scott A.

    1988-01-01

    Since 1983, when the David Douglas Public Schools (Portland, Oregon) converted 30 buses to propane fuel, the district has saved $75,000 in fuel and maintenance costs. Propane is priced consistently lower than gasoline and burns cleaner. Since propane engines do not require a carburetor, there are fewer maintenance problems. (MLH)

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

    PubMed

    Chiang, Hung-Lung; Wu, Trong-Neng; Ho, Yung-Shou; Zeng, Li-Xuan

    2014-07-15

    Carbon materials including carbon spheres and nanotubes were formed from acetylene decomposition on hydrogen-reduced SBA-15 and Ni-SBA-15 at 650-850°C. The physicochemical characteristics of SBA-15, Ni-SBA-15 and carbon materials were analyzed by field emission scanning electronic microscopy (FE-SEM), Raman spectrometry, and energy dispersive spectrometry (EDS). In addition, the contents of polyaromatic hydrocarbons (PAHs) in the tar and residue and volatile organic compounds (VOCs) in the exhaust were determined during acetylene decomposition on SBA-15 and Ni-SBA-15. Spherical carbon materials were observed on SBA-15 during acetylene decomposition at 750 and 850°C. Carbon filaments and ball spheres were formed on Ni-SBA-15 at 650-850°C. Raman spectroscopy revealed peaks at 1290 (D-band, disorder mode, amorphous carbon) and 1590 (G-band, graphite sp(2) structure)cm(-1). Naphthalene (2 rings), pyrene (4 rings), phenanthrene (3 rings), and fluoranthene (4 rings) were major PAHs in tar and residues. Exhaust constituents of hydrocarbon (as propane), H2, and C2H2 were 3.9-2.6/2.7-1.5, 1.4-2.8/2.6-4.3, 4.2-2.4/3.2-1.7% when acetylene was decomposed on SBA-15/Ni-SBA-15, respectively, corresponding to temperatures ranging from 650 to 850°C. The concentrations of 52 VOCs ranged from 9359 to 5658 and 2488 to 1104ppm for SBA-15 and Ni-SBA-15 respectively, at acetylene decomposition temperatures from 650 to 850°C, and the aromatics contributed more than 87% fraction of VOC concentrations.

  18. Case Study - Propane School Bus Fleets

    SciTech Connect

    Laughlin, M; Burnham, A.

    2014-08-31

    As part of the U.S. Department of Energy’s (DOE’s) effort to deploy transportation technologies that reduce U.S. dependence on imported petroleum, this study examines five school districts, one in Virginia and four in Texas, successful use of propane school buses. These school districts used school buses equipped with the newly developed liquid propane injection system that improves vehicle performance. Some of the school districts in this study saved nearly 50% on a cost per mile basis for fuel and maintenance relative to diesel. Using Argonne National Laboratory’s Alternative Fuel Life-Cycle Environmental and Economic Transportation (AFLEET) Tool developed for the DOE’s Clean Cities program to help Clean Cities stakeholders estimate petroleum use, greenhouse gas (GHG) emissions, air pollutant emissions and cost of ownership of light-duty and heavy-duty vehicles, the results showed payback period ranges from 3—8 years, recouping the incremental cost of the vehicles and infrastructure. Overall, fuel economy for these propane vehicles is close to that of displaced diesel vehicles, on an energy-equivalent basis. In addition, the 110 propane buses examined demonstrated petroleum displacement, 212,000 diesel gallon equivalents per year, and GHG benefits of 770 tons per year.

  19. 21 CFR 582.1655 - Propane.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... used in accordance with good manufacturing or feeding practice. ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Propane. 582.1655 Section 582.1655 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS,...

  20. 77 FR 31842 - Thrifty Propane, Inc.

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-30

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission Thrifty Propane, Inc. v. Enterprise TE Products Pipeline Co., LLC; Notice of... Enterprise TE Products Pipeline Co., LLC (Respondent) alleging that the Respondent intends to make...

  1. Portland Public School Children Move with Propane

    SciTech Connect

    Not Available

    2004-04-01

    This 2-page Clean Cities fact sheet describes the use of propane as a fuel source for Portland Public Schools' fleet of buses. It includes information on the history of the program, along with contact information for the local Clean Cities Coordinator and Portland Public Schools.

  2. Case Study - Propane Bakery Delivery Step Vans

    SciTech Connect

    Laughlin, M.; Burnham, A.

    2016-04-01

    A switch to propane from diesel by a major Midwest bakery fleet showed promising results, including a significant displacement of petroleum, a drop in greenhouse gases and a fuel cost savings of seven cents per mile, according to a study recently completed by the U.S. Department of Energy's Argonne National Laboratory for the Clean Cities program.

  3. Can Analysis of Acetylene and Its Biodegradation Products in Enceladus Plumes be Used to Detect the Presence of Sub-Surface Life?

    NASA Astrophysics Data System (ADS)

    Miller, L. G.; Baesman, S. M.; Oremland, R. S.

    2014-12-01

    The search for biosignatures of life on Earth includes measurement of the stable isotope fractionation of reactants and products attributed to enzymatic processes and comparison with the often smaller chemical (abiotic) fractionation. We propose that this approach might be applied to study the origin and fate of organic compounds contained in water vapor plumes emanating from Enceladus or other icy bodies, perhaps revealing information about the potential for biology occurring within a sub-surface "habitable" zone. Methanol and C2-hydrocarbons including ethylene, ethane and acetylene (C2H2) have been identified in the plumes of Enceladus. Biological degradation of acetylene proceeds by anaerobic fermentation via acetylene hydratase through acetaldehyde, with a second enzyme (acetaldehyde dismutase) forming acetate and ethanol. We found that incubation of cultures of acetylene-fermenting bacteria exhibit a kinetic isotope effect (KIE) associated with the net removal of C2H2. Consumption of acetylene by both growing and washed-cell cultures of bacteria closely related to Pelobacter acetylenicus (e.g, strain SFB93) was accompanied by a carbon isotopic fractionation of about 2 per mil (KIE = 1.8-2.7 ‰), a result we are examining with other cultures of acetylene fermenters. In addition, we are measuring the carbon isotopic composition of acetaldehyde, ethanol and acetate during fermentation to learn whether these products are fractionated sufficiently, relative to their substrate, to warrant measurement of their isotopic composition in Enceladus (or Europa) plumes to indicate enzymatic activity in liquid environments below the crust of these moons.

  4. 75 FR 5707 - Revising Standards Referenced in the Acetylene Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-04

    ... in the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION... accompanied its direct-final rule revising the Acetylene Standard for general industry. DATES: As of February...- final rule to update the incorporated references in its Acetylene Standard for general industry at...

  5. 77 FR 13969 - Revising Standards Referenced in the Acetylene Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-08

    ... the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Department of... date of its direct final rule that revises the Acetylene Standard for general industry by updating the... that revised the Acetylene Standard for general industry by updating a reference to the Compressed...

  6. 77 FR 13997 - Revising Standards Referenced in the Acetylene Standard

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-03-08

    ... in the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Labor. ACTION... accompanied its direct-final rule revising the Acetylene Standard for general industry. DATES: Effective March...-final rule to update the incorporated references in its Acetylene Standard for general industry at...

  7. 46 CFR 154.1735 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Methyl acetylene-propadiene mixture. 154.1735 Section... Operating Requirements § 154.1735 Methyl acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must be within the following limits or specially approved by...

  8. 46 CFR 154.1735 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Methyl acetylene-propadiene mixture. 154.1735 Section... Operating Requirements § 154.1735 Methyl acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must be within the following limits or specially approved by...

  9. Vapor pressures of acetylene at low temperatures

    NASA Technical Reports Server (NTRS)

    Masterson, C. M.; Allen, John E., Jr.; Kraus, G. F.; Khanna, R. K.

    1990-01-01

    The atmospheres of many of the outer planets and their satellites contain a large number of hydrocarbon species. In particular, acetylene (C2H2) has been identified at Jupiter, Saturn and its satellite Titan, Uranus and Neptune. In the lower atmospheres of these planets, where colder temperatures prevail, the condensation and/or freezing of acetylene is probable. In order to obtain accurate models of the acetylene in these atmospheres, it is necessary to have a complete understanding of its vapor pressures at low temperatures. Vapor pressures at low temperatures for acetylene are being determined. The vapor pressures are measured with two different techniques in order to cover a wide range of temperatures and pressures. In the first, the acetylene is placed in a sample tube which is immersed in a low temperature solvent/liquid nitrogen slush bath whose temperature is measured with a thermocouple. The vapor pressure is then measured directly with a capacitance manometer. For lower pressures, a second technique which was called the thin-film infrared method (TFIR) was developed. It involves measuring the disappearance rate of a thin film of acetylene at a particular temperature. The spectra are then analyzed using previously determined extinction coefficient values, to determine the disappearance rate R (where R = delta n/delta t, the number of molecules that disappear per unit time). This can be related to the vapor pressure directly. This technique facilitates measurement of the lower temperatures and pressures. Both techniques have been calibrated using CO2, and have shown good agreement with the existing literature data.

  10. Simultaneous Measurement of Acetylene Reduction and Respiratory Gas Exchange of Attached Root Nodules 1

    PubMed Central

    Winship, Lawrence J.; Tjepkema, John D.

    1982-01-01

    A method was developed for the simultaneous measurement of acetylene reduction, carbon dioxide evolution and oxygen uptake by individual root nodules of intact nitrogen-fixing plants (Alnus rubra Bong.). The nodules were enclosed in a temperature-controlled leak-tight cuvette. Assay gas mixtures were passed through the cuvette at a constant, known flow rate and gas exchange was measured by the difference between inlet and outlet gas compositions. Gas concentrations were assayed by a combination of an automated gas chromatograph and a programmable electronic integrator. Carbon dioxide and ethylene evolution were determined with a coefficient of variation which was less than 2%, whereas the coefficient of variation for oxygen uptake measurements was less than 5%. Nodules subjected to repeated removal from and reinsertion into the cuvette and to long exposures of 10% v/v acetylene showed no irreversible decline in respiration or acetylene reduction. This system offers long-term stability and freedom from disturbance artifacts plus the ability to monitor continuously, rapidly and specifically the changes in root nodule activity caused by environmental perturbation. PMID:16662496

  11. Thermodynamics of acetylene van der Waals dimerization

    NASA Technical Reports Server (NTRS)

    Colussi, A. J.; Sander, S. P.; Friedl, R. R.

    1991-01-01

    Integrated band intensities of the 620/cm absorption in (C2H2)2 are measured by FTIR spectroscopy at constant acetylene pressure between 198 and 273 K. These data, in conjunction with ab initio results for (C2H2)2, are used for the statistical evaluation of the equilibrium constant Kp(T) for acetylene-cluster dimerization. The present results are used to clarify the role of molecular clusters in chemical systems at or near equilibrium, in particular in Titan's stratosphere.

  12. A DFT+U study of acetylene selective hydrogenation on oxygen defective anatase (101) and rutile (110) TiO2 supported Pd4 cluster

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Lv, Cun-Qin; Guo, Yong; Wang, Gui-Chang

    2012-03-01

    The reaction mechanisms for selective acetylene hydrogenation on three different supports, Pd4 cluster, oxygen defective anatase (101), and rutile (110) titania supported Pd4, cluster are studied using the density functional theory calculations with a Hubbard U correction (DFT+U). The present calculations show that the defect anatase support binds Pd4 cluster more strongly than that of rutile titania due to the existence of Ti3+ in anatase titania. Consequently, the binding energies of adsorbed species such as acetylene and ethylene on Pd4 cluster become weaker on anatase supported catalysts compared to the rutile supported Pd4 cluster. Anatase catalyst has higher selectivity of acetylene hydrogenation than rutile catalyst. On the one hand, the activation energies of ethylene formation are similar on the two catalysts, while they vary a lot on ethyl formation. The rutile supported Pd catalyst with lower activation energy is preferable for further hydrogenation. On the other hand, the relatively weak adsorption energy of ethylene is gained on anatase surface, which means it is easier for ethylene desorption, hence getting higher selectivity. For further understanding, the energy decomposition method and micro-kinetic analysis are also introduced.

  13. Adsorptive separation of propylene-propane mixtures

    SciTech Connect

    Jaervelin, H.; Fair, J.R. )

    1993-10-01

    The separation of propylene-propane mixtures is of great commercial importance and is carried out by fractional distillation. It is claimed to be the most energy-intensive distillation practiced in the United States. The purpose of this paper is to describe experimental work that suggests a practical alternative to distillation for separating the C[sub 3] hydrocarbons: adsorption. As studied, the process involves three adsorptive steps: initial separation with molecular sieves with heavy dilution with an inert gas; separation of propylene and propane separately from the inert gas, using activated carbon; and drying of the product streams with any of several available desiccants. The research information presented here deals with the initial step and includes both equilibrium and kinetic data. Isotherms are provided for propylene and propane adsorbed on three zeolites, activated alumina, silica gel, and coconut-based activated carbon. Breakthrough data are provided for both adsorption and regeneration steps for the zeolites, which were found to be superior to the other adsorbents for breakthrough separations. A flow diagram for the complete proposed process is included.

  14. Low Cost Aromatic Acetylene and Oligomeric Benzils and Their Conversion to Acetylene Terminated Quinoxalines

    DTIC Science & Technology

    1982-07-01

    methyl-3-butyn-2-ol by warming with methylbutynol in the presence of cuprous iodide in triethylamine was very rapid, indicating that the acetylene can...8.6/1 actually caused a significant rate increase in Runs 75, 114, and 115. The presence of cuprous iodide shows little effect in the reaction of...bromoarenes with olefins.(9) The effect in the acetylene reaction, how- ever, is very significant. Cuprous iodide probably is involved in two modes

  15. Living on acetylene. A primordial energy source.

    PubMed

    Ten Brink, Felix

    2014-01-01

    The tungsten iron-sulfur enzyme acetylene hydratase catalyzes the conversion of acetylene to acetaldehyde by addition of one water molecule to the C-C triple bond. For a member of the dimethylsulfoxide (DMSO) reductase family this is a rather unique reaction, since it does not involve a net electron transfer. The acetylene hydratase from the strictly anaerobic bacterium Pelobacter acetylenicus is so far the only known and characterized acetylene hydratase. With a crystal structure solved at 1.26 Å resolution and several amino acids around the active site exchanged by site-directed mutagenesis, many key features have been explored to understand the function of this novel tungsten enzyme. However, the exact reaction mechanism remains unsolved. Trapped in the reduced W(IV) state, the active site consists of an octahedrally coordinated tungsten ion with a tightly bound water molecule. An aspartate residue in close proximity, forming a short hydrogen bond to the water molecule, was shown to be essential for enzyme activity. The arrangement is completed by a small hydrophobic pocket at the end of an access funnel that is distinct from all other enzymes of the DMSO reductase family.

  16. Influence of and additives on acetylene detonation

    NASA Astrophysics Data System (ADS)

    Drakon, A.; Emelianov, A.; Eremin, A.

    2014-03-01

    The influence of and admixtures (known as detonation suppressors for combustible mixtures) on the development of acetylene detonation was experimentally investigated in a shock tube. The time-resolved images of detonation wave development and propagation were registered using a high-speed streak camera. Shock wave velocity and pressure profiles were measured by five calibrated piezoelectric gauges and the formation of condensed particles was detected by laser light extinction. The induction time of detonation development was determined as the moment of a pressure rise at the end plate of the shock tube. It was shown that additive had no influence on the induction time. For , a significant promoting effect was observed. A simplified kinetic model was suggested and characteristic rates of diacetylene formation were estimated as the limiting stage of acetylene polymerisation. An analysis of the obtained data indicated that the promoting species is atomic chlorine formed by pyrolysis, which interacts with acetylene and produces radical, initiating a chain mechanism of acetylene decomposition. The results of kinetic modelling agree well with the experimental data.

  17. Hydration of Acetylene: A 125th Anniversary

    ERIC Educational Resources Information Center

    Ponomarev, Dmitry A.; Shevchenko, Sergey M.

    2007-01-01

    The year 2006 is the 125th anniversary of a chemical reaction, the discovery of which by Mikhail Kucherov had a profound effect on the development of industrial chemistry in the 19-20th centuries. This was the hydration of alkynes catalyzed by mercury ions that made possible industrial production of acetaldehyde from acetylene. Historical…

  18. Induction of Olefin Metathesis by Acetylenes.

    DTIC Science & Technology

    1980-11-20

    essentially that of 2. The acetylene is thus an activator, but unlike the organometallic co- catalysts like C2 H5A1C1 2 , which it replaces, it is unique in...J.C.; Moulijn, J.A. Adv. Catal. 1975, 24, 131. (4) Some of the results were discussed at the 3rd NSF Workshop on Organo - metallic Chemistry, Pingree

  19. Acetylene hydrogenation over structured Au-Pd catalysts.

    PubMed

    McCue, Alan J; Baker, Richard T; Anderson, James A

    2016-07-04

    AuPd nanoparticles were prepared following a methodology designed to produce core-shell structures (an Au core and a Pd shell). Characterisation suggested that slow addition of the shell metal favoured deposition onto the pre-formed core, whereas more rapid addition favoured the formation of a monometallic Pd phase in addition to some nanoparticles with the core-shell morphology. When used for the selective hydrogenation of acetylene, samples that possessed monometallic Pd particles favoured over-hydrogenation to form ethane. A sample prepared by the slow addition of a small amount of Pd resulted in the formation of a core-shell structure but with an incomplete Pd shell layer. This material exhibited a completely different product selectivity with ethylene and oligomers forming as the major products as opposed to ethane. The improved performance was thought to be as a result of the absence of Pd particles, which are capable of forming a Pd-hydride phase, with enhanced oligomer selectivity associated with reaction on uncovered Au atoms.

  20. 77 FR 2293 - AmeriGas Propane, L.P., AmeriGas Propane, Inc., Energy Transfer Partners, L.P., and Energy...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-17

    ... AmeriGas Propane, L.P., AmeriGas Propane, Inc., Energy Transfer Partners, L.P., and Energy Transfer...'') with AmeriGas Propane, L.P. (``AmeriGas''), AmeriGas Propane, Inc., Energy Transfer Partners, L.P. (``ETP''), and Energy Transfer Partners GP, L.P. (``ETP GP''), which is designed to guard...

  1. Coal pyrolysis to acetylene using dc hydrogen plasma torch: effects of system variables on acetylene concentration

    NASA Astrophysics Data System (ADS)

    Chen, Longwei; Meng, Yuedong; Shen, Jie; Shu, Xingsheng; Fang, Shidong; Xiong, Xinyang

    2009-03-01

    In order to unveil the inner mechanisms that determine acetylene concentration, experimental studies on the effect of several parameters such as plasma torch power, hydrogen flux and coal flux were carried out from coal pyrolysis in a dc plasma torch. Xinjiang long flame coals including volatile constituents at a level of about 42% were used in the experiment. Under the following experimental conditions, namely plasma torch power, hydrogen flow rate and pulverized coal feed speed of 2.12 MW, 32 kg h-1 and 900 kg h-1, respectively, acetylene volume concentration of about 9.4% was achieved. The experimental results indicate that parameters such as plasma torch power and coal flux play important roles in the formation of acetylene. Acetylene concentration increases inconspicuously with hydrogen flux. A chemical thermodynamic equilibrium model using the free energy method is introduced in this paper to numerically simulate each experimental condition. The numerical results are qualitatively consistent with the experimental results. Two parameters, i.e. the gas temperature and the ratio of hydrogen/carbon, are considered to be the dominant and independent factors that determine acetylene concentration.

  2. Opposite influence of haloalkanes on combustion and pyrolysis of acetylene

    NASA Astrophysics Data System (ADS)

    Drakon, A. V.; Emelianov, A. V.; Eremin, A. V.; Mikheyeva, E. Yu

    2015-11-01

    An influence of haloalkanes CF3H and CCl4 (known as inflammation and explosion suppressors) on combustion and pyrolysis of acetylene behind shock waves was experimentally studied. While ignition delay times in stoihiometric acetylene-oxygen mixtures were expectedly increased by halogenoalkanes admixtures, the induction times of carbon particle formation at acetylene pyrolysis were dramatically reduced in presence of CCl4. A simplified kinetic model was suggested and characteristic rates of diacetylene C4H2 formation were estimated as a limiting stage of acetylene polymerization. An analysis of obtained data has indicated that promoting species is atomic chlorine forming in CCl4 pyrolysis, which interacts with acetylene and produces C2H radical, initiating a chain mechanism of acetylene decomposition. The results of kinetic modeling agree well with experimental data.

  3. Two new acetylenic compounds from Asparagus officinalis.

    PubMed

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

    2016-01-01

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

  4. Aromatic Radicals-Acetylene Particulate Matter Chemistry

    DTIC Science & Technology

    2011-12-01

    atmosphere1. In addition to acute respiratory problems, long-term effects include lung cancer and cardiopulmonary diseases , as studied by Pope at al...problems such as ischemic heart disease , fatal arrhythmia, and congestive heart failure4,5. Strategies to reduce fine particulate matter (PM...acetylene reaction have been made by Fahr and Stein15, who deduced an Arrhenius expression in a 4 temperature range between 1000 and 1330 K in

  5. Cross Sections for Electron Collisions with Acetylene

    NASA Astrophysics Data System (ADS)

    Song, Mi-Young; Yoon, Jung-Sik; Cho, Hyuck; Karwasz, Grzegorz P.; Kokoouline, Viatcheslav; Nakamura, Yoshiharu; Tennyson, Jonathan

    2017-03-01

    Cross section data are compiled from the literature for electron collisions with the acetylene (HCCH) molecule. Cross sections are collected and reviewed for total scattering, elastic scattering, momentum transfer, excitations of rotational and vibrational states, dissociation, ionization, and dissociative attachment. The data derived from swarm experiments are also considered. For each of these processes, the recommended values of the cross sections are presented. The literature has been surveyed through early 2016.

  6. Reduced chemical kinetics for propane combustion

    NASA Technical Reports Server (NTRS)

    Ying, Shuh-Jing; Nguyen, Hung Lee

    1990-01-01

    It is pointed out that a detailed chemical kinetics mechanism for the combustion of propane consists of 40 chemical species and 118 elementary chemical reactions. An attempt is made to reduce the number of chemical species and elementary chemical reactions so that the computer run times and storage requirements may be greatly reduced in three-dimensional gas turbine combustion flow calculations, while maintaining accurate predictions of the propane combustion and exhaust emissions. By way of a sensitivity analysis, the species of interest and chemical reactions are classified in descending order of importance. Nineteen species are chosen, and their pressure, temperature, and concentration profiles are presented for the reduced mechanisms, which are then compared with those from the full 118 reactions. It is found that 45 reactions involving 27 species have to be kept for comparable agreement. A comparison of the results obtained from the 45 reactions to that of the full 118 shows that the pressure and temperature profiles and concentrations of C3H8, O2, N2, H2O, CO, and CO2 are within 10 percent of maximum change.

  7. High temperature polymer from maleimide-acetylene terminated monomers

    NASA Technical Reports Server (NTRS)

    Gerber, Margaret K. (Inventor); St.clair, Terry L. (Inventor)

    1993-01-01

    Thermally stable, glassy polymeric materials were prepared from maleimide-acetylene terminated monomeric materials by several methods. The monomers were heated to self-polymerize. The A-B structure of the monomer allowed it to polymerize with either bismaleimide monomers/oligomers or bis-acetylene monomers/oligomers. Copolymerization can also take place by mixing bismaleimide and bisacetylene monomers/oligomers with the maleimide-acetylene terminated monomers to yield homogenous glassy polymers.

  8. Extending the Lifetime of Hyperpolarized Propane Gas through Reversible Dissolution.

    PubMed

    Burueva, Dudari B; Romanov, Alexey S; Salnikov, Oleg G; Zhivonitko, Vladimir V; Chen, Yu-Wen; Barskiy, Danila A; Chekmenev, Eduard Y; Hwang, Dennis W; Kovtunov, Kirill V; Koptyug, Igor V

    2017-03-02

    Hyperpolarized (HP) propane produced by the parahydrogen-induced polarization (PHIP) technique has been recently introduced as a promising contrast agent for functional lung magnetic resonance (MR) imaging. However, its short lifetime due to a spin-lattice relaxation time T1 of less than 1 s in the gas phase is a significant translational challenge for its potential biomedical applications. The previously demonstrated approach for extending the lifetime of the HP propane state through long-lived spin states allows the HP propane lifetime to be increased by a factor of ∼3. Here, we demonstrate that a remarkable increase in the propane hyperpolarization decay time at high magnetic field (7.1 T) can be achieved by its dissolution in deuterated organic solvents (acetone-d6 or methanol-d4). The approximate values of the HP decay time for propane dissolved in acetone-d6 are 35.1 and 28.6 s for the CH2 group and the CH3 group, respectively (similar values were obtained for propane dissolved in methanol-d4), which are ∼50 times larger than the gaseous propane T1 value. Furthermore, we show that it is possible to retrieve HP propane from solution to the gas phase with the preservation of hyperpolarization.

  9. Synthesis of functional poly(disubstituted acetylene)s through the post-polymerization modification route.

    PubMed

    Gao, Yuan; Wang, Xiao; Sun, Jing Zhi; Tang, Ben Zhong

    2015-04-01

    We report the recent progress in the preparation of functional poly(disubstituted acetylene)s (PDSAs) through post-polymerization modification routes. The metathesis polymerization of disubstituted acetylene monomers activated by Mo/W-Sn complex catalysts, which do not tolerate highly polar functionalities, was assumed to be a key step in the polymer synthetic procedures. We and other groups have explored several approaches to prepare PDSAs with latent reactive functionalities, which are inactive to Mo/W-Sn complex catalysts but can be used as highly reactive sites for post-polymerization modification. Click chemistry, Michael-type addition reactions, the use of activated esters and other strategies are demonstrated by recently published examples. These works indicate that post-polymerization modification is an efficient route to the synthesis of various functional PDSAs.

  10. High-resolution FTIR spectroscopy of the ν3 band of methyl acetylene-d

    NASA Astrophysics Data System (ADS)

    Pal, Ayan Kumar; Kshirsagar, R. J.

    2014-04-01

    The high-resolution Fourier transform spectrum of methyl acetylene-d1 (CH3CCD) at room temperature has been recorded in the region of the ν3 band (1980-2035 cm-1) at an apodized resolution of 0.004 cm-1. About 600 vibration-rotation transitions have been assigned, with J upto 36 and K upto 6. The spectrum shows the presence of several perturbations. The observed minus calculated deviation of the fit for K = 4 subband is much more than the expected, shows the presence of Fermi resonance with the nearby vibrational state.

  11. Emissions results for dedicated propane Chrysler minivans: the 1996 propane vehicle challenge

    SciTech Connect

    Buitrago, C.; Sluder, S.; Larsen, R.

    1997-02-01

    The U.S. Department of Energy (US DOE), through Argonne National Laboratory, and in cooperation with Natural Resources-Canada and Chrysler Canada, sponsored and organized the 1996 Propane Vehicle Challenge (PVC). For this competition , 13 university teams from North America each received a stock Chrysler minivan to be converted to dedicated propane operation while maintaining maximum production feasibility. The converted vehicles were tested for performance (driveability, cold- and hot-start, acceleration, range, and fuel economy) and exhaust emissions. Of the 13 entries for the 1996 PVC, 10 completed all of the events scheduled, including the emissions test. The schools used a variety of fuel-management, fuel-phase and engine-control strategies, but their strategies can be summarized as three main types: liquid fuel-injection, gaseous fuel-injection, and gaseous carburetor. The converted vehicles performed similarly to the gasoline minivan. The University of Windsor`s minivan had the lowest emissions attaining ULEV levels with a gaseous-injected engine. The Texas A&M vehicle, which had a gaseous-fuel injection system, and the GMI Engineering and Management Institute`s vehicle, which had a liquid-injection system both reached LEV levels. Vehicles with an injection fuel system (liquid or gaseous) performed better in terms of emissions than carbureted systems. Liquid injection appeared to be the best option for fuel metering and control for propane, but more research and calibration are necessary to improve the reliability and performance of this design.

  12. A biogeochemical and genetic survey of acetylene fermentation by environmental samples and bacterial isolates

    USGS Publications Warehouse

    Miller, Laurence G.; Baesman, Shaun M.; Kirshtein, Julie; Voytek, Mary A.; Oremland, Ronald S.

    2013-01-01

    Anoxic samples (sediment and groundwater) from 13 chemically diverse field sites were assayed for their ability to consume acetylene (C2H2). Over incubation periods ranging from ˜ 10 to 80 days, selected samples from 7 of the 13 tested sites displayed significant C2H2 removal. No significant formation of ethylene was noted in these incubations; therefore, C2H2 consumption could be attributed to acetylene hydratase (AH) rather than nitrogenase activity. This putative AH (PAH) activity was observed in only 21% of the total of assayed samples, while amplification of AH genes from extracted DNA using degenerate primers derived from Pelobacter acetylenicus occurred in even fewer (9.8%) samples. Acetylene-fermenting bacteria were isolated as a pure culture from the sediments of a tidal mudflat in San Francisco Bay (SFB93) and as an enrichment culture from freshwater Searsville Lake (SV7). Comparison of 16S rDNA clone libraries revealed that SFB93 was closely related to P. carbolinicus, while SV7 consisted of several unrelated bacteria. AH gene was amplified from SFB93 but not SV7. The inability of the primers to generate amplicons in the SV7 enrichment, as well as from several of the environmental samples that displayed PAH activity, implied that either the primers were too highly constrained in their specificity or that there was a different type of AH gene in these environmental samples than occurs in P. acetylenicus. The significance of this work with regard to the search for life in the outer Solar System, where C2HL2 is abundant, is discussed.

  13. Rotational spectroscopy and molecular structure of the 1-chloro-1-fluoroethylene-acetylene complex.

    PubMed

    Leung, Helen O; Marshall, Mark D; Grimes, David D

    2011-01-21

    Guided by ab initio calculations, Fourier transform microwave spectra in the 6-21 GHz region are obtained for seven isotopomers of the complex formed between 1-chloro-1-fluoroethylene and acetylene. These include the four possible combinations of (35)Cl- and (37)Cl-containing CH(2)CClF with the most abundant acetylene isotopic modification, HCCH, and its H(13)C(13)CH analogue, as well as three singly substituted deuterated isotopomers. Analysis of the spectra determines the rotational constants and additionally, the complete chlorine quadrupole hyperfine coupling tensors in both the inertial and principal electric field gradient axis systems, and where appropriate, the diagonal components of the deuterium quadrupole coupling tensors. The inertial information contained in the rotational constants provides the structure for CH(2)CClF-HCCH: a primary, hydrogen bonding interaction existing between the HCCH donor and the F atom acceptor on the 1-chloro-1-fluoroethylene moiety, while a secondary interaction occurs between the acetylenic bond on the HCCH molecule and the H atom cis to the hydrogen-bonded F atom on the substituted ethylene, which causes the hydrogen bond to deviate from linearity. This is similar to the structure obtained for 1,1-difluoroethylene-HCCH [H. O. Leung and M. D. Marshall, J. Chem. Phys. 126, 154301 (2006)], and indeed, to within experimental uncertainty, the intermolecular interactions in CH(2)CClF-HCCH and its 1,1-difluoroethylene counterpart are practically indistinguishable, even though ab initio calculations at the MP2∕6-311G++(2d, 2p) level suggest that the former complex is more strongly bound.

  14. RECRYSTALLIZATION OF PMDA AND SYNTHESIS OF AN ACETYLENIC DIAMINE

    SciTech Connect

    Sanner, R; Cook, R C

    2004-09-21

    This memo provides documentation for the method of recrystallization of pyromeletic dianhydride (PMDA), the dianhydride used in the vapor deposition of Kapton-like polyimide for ICF shell ablators and for the synthesis of bis(3-aminophenyl) acetylene, a unique acetylenic diamine developed for vapor deposition testing.

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

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-05

    ... the Acetylene Standard AGENCY: Occupational Safety and Health Administration (OSHA), Department of... rulemaking, the Agency is proposing to revise its Acetylene Standard for general industry by updating a... Companion Proposed Rule C. Request for Comment III. Summary and Explanation of Revisions to the...

  16. Spectroscopic study of acetylene and hydrogen cyanide

    NASA Astrophysics Data System (ADS)

    Rozario, Hoimonti Immaculata

    High-resolution molecular spectroscopy has been used to study acetylene line parameters and emission spectra of hydrogen cyanide. All acetylene spectra were recorded in our laboratory at the University of Lethbridge using a 3-channel tuneable diode laser spectrometer. N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213-333K to obtain the temperature dependences of broadening and shift coefficients. The Voigt and hard-collision line profile models were used to retrieve the line parameters. The line-broadening and line-shift coefficients as well as their temperature-dependent parameters have been also evaluated theoretically, in the frame work of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole--quadrupole and pairwise atom--atom interactions as well as on exact trajectories driven by an effective isotropic potential. The experimental results for both N2-broadening and shifting show good agreement with the theoretical results. We have studied the line intensities of the 1vl 20←0v120 band system from the HCN emission spectrum. The infrared emission spectrum of H12C 14N was measured at the Justus-Liebig University, Giessen, Germany. The emission spectrum was analyzed with the spectrum analysis software Symath running using Mathematica as a platform. This approach allowed us to retrieve information on band intensity parameters.

  17. Study on propane-butane gas storage by hydrate technology

    NASA Astrophysics Data System (ADS)

    Hamidi, Nurkholis; Wijayanti, Widya; Widhiyanuriyawan, Denny

    2016-03-01

    Different technology has been applied to store and transport gas fuel. In this work the storage of gas mixture of propane-butane by hydrate technology was studied. The investigation was done on the effect of crystallizer rotation speed on the formation of propane-butane hydrate. The hydrates were formed using crystallizer with rotation speed of 100, 200, and 300 rpm. The formation of gas hydrates was done at initial pressure of 3 bar and temperature of 274K. The results indicated that the higher rotation speed was found to increase the formation rate of propane-butane hydrate and improve the hydrates stability.

  18. Low Cost Routes to Acetylenic Intermediates

    DTIC Science & Technology

    1979-12-01

    palladium as catalyst, diethyl amine as solvent and cuprous iodide as cocatalyst (Equation 1). Cl 2Pd (PPh 3)2 ArX + H-CE-C-R Ar-C-C-R (1) Et 2 NH...an acetylene and cuprous iodide was not brought to a conclusion because this work was interrupted by work on the ATS system. We synthesized a variety...triethyl amine and cuprous iodide. At 940, the production of the substituted phenylacetylene and the disappearance of bromobenzene were examined by GC

  19. Hydrothermal synthesis and acetylene sensing properties of variety low dimensional zinc oxide nanostructures.

    PubMed

    Zhou, Qu; Chen, Weigen; Peng, Shudi; Zeng, Wen

    2014-01-01

    Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), glycine, and ethylene glycol (EG) play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2), one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2 sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2 gas sensor for practical application.

  20. Hydrothermal Synthesis and Acetylene Sensing Properties of Variety Low Dimensional Zinc Oxide Nanostructures

    PubMed Central

    Chen, Weigen; Peng, Shudi; Zeng, Wen

    2014-01-01

    Various morphologies of low dimensional ZnO nanostructures, including spheres, rods, sheets, and wires, were successfully synthesized using a simple and facile hydrothermal method assisted with different surfactants. Zinc acetate dihydrate was chosen as the precursors of ZnO nanostructures. We found that polyethylene glycol (PEG), polyvinylpyrrolidone (PVP), glycine, and ethylene glycol (EG) play critical roles in the morphologies and microstructures of the synthesized nanostructures, and a series of possible growth processes were discussed in detail. Gas sensors were fabricated using screen-printing technology, and their sensing properties towards acetylene gas (C2H2), one of the most important arc discharge characteristic gases dissolved in oil-filled power equipments, were systematically measured. The ZnO nanowires based sensor exhibits excellent C2H2 sensing behaviors than those of ZnO nanosheets, nanorods, and nanospheres, indicating a feasible way to develop high-performance C2H2 gas sensor for practical application. PMID:24672324

  1. Importance of surface carbide formation on the activity and selectivity of Pd surfaces in the selective hydrogenation of acetylene

    NASA Astrophysics Data System (ADS)

    Yang, Bo; Burch, Robbie; Hardacre, Christopher; Hu, P.; Hughes, Philip

    2016-04-01

    A recent experimental investigation (Kim et al. J. Catal. 306 (2013) 146-154) on the selective hydrogenation of acetylene over Pd nanoparticles with different shapes concluded that Pd(100) showed higher activity and selectivity than Pd(111) for acetylene hydrogenation. However, our recent density functional calculations (Yang et al. J. Catal. 305 (2013) 264-276) observed that the clean Pd(111) surface should result in higher activity and ethylene selectivity compared with the clean Pd(100) surface for acetylene hydrogenation. In the current work, using density functional theory calculations, we find that Pd(100) in the carbide form gives rise to higher activity and selectivity than Pd(111) carbide. These results indicate that the catalyst surface is most likely in the carbide form under the experimental reaction conditions. Furthermore, the adsorption energies of hydrogen atoms as a function of the hydrogen coverage at the surface and subsurface sites over Pd(100) are compared with those over Pd(111), and it is found that the adsorption of hydrogen atoms is always less favoured on Pd(100) over the whole coverage range. This suggests that the Pd(100) hydride surface will be less stable than the Pd(111) hydride surface, which is also in accordance with the experimental results reported.

  2. Low-temperature superacid catalysis: Reactions of n - butane and propane catalyzed by iron- and manganese-promoted sulfated zirconia

    SciTech Connect

    Tsz-Keung, Cheung; d`Itri, J.L.; Lange, F.C.; Gates, B.C.

    1995-12-31

    The primary goal of this project is to evaluate the potential value of solid superacid catalysts of the sulfated zirconia type for light hydrocarbon conversion. The key experiments catalytic testing of the performance of such catalysts in a flow reactor fed with streams containing, for example, n-butane or propane. Fe- and Mn-promoted sulfated zirconia was used to catalyze the conversion of n-butane at atmospheric pressure, 225-450{degrees}C, and n-butane partial pressures in the range of 0.0025-0.01 atm. At temperatures <225{degrees}C, these reactions were accompanied by cracking; at temperatures >350{degrees}C, cracking and isomerization occurred. Catalyst deactivation, resulting at least in part from coke formation, was rapid. The primary cracking products were methane, ethane, ethylene, and propylene. The observation of these products along with an ethane/ethylene molar ratio of nearly 1 at 450{degrees}C is consistent with cracking occurring, at least in part, by the Haag-Dessau mechanism, whereby the strongly acidic catalyst protonates n-butane to give carbonium ions. The rate of methane formation from n-butane cracking catalyzed by Fe- and Mn-promoted sulfated zirconia at 450{degrees}C was about 3 x 10{sup -8} mol/(g of catalyst {center_dot}s). The observation of butanes, pentanes, and methane as products is consistent with Olah superacid chemistry, whereby propane is first protonated by a very strong acid to form a carbonium ion. The carbonium ion then decomposes into methane and an ethyl cation which undergoes oligocondensation reactions with propane to form higher molecular weight alkanes. The results are consistent with the identification of iron- and manganese-promoted sulfated zirconia as a superacid.

  3. Acetylene-Based Materials in Organic Photovoltaics

    PubMed Central

    Silvestri, Fabio; Marrocchi, Assunta

    2010-01-01

    Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C60, and their use as the active materials in photovoltaic devices. PMID:20480031

  4. Acetylene-based materials in organic photovoltaics.

    PubMed

    Silvestri, Fabio; Marrocchi, Assunta

    2010-04-08

    Fossil fuel alternatives, such as solar energy, are moving to the forefront in a variety of research fields. Organic photovoltaic systems hold the promise of a lightweight, flexible, cost-effective solar energy conversion platform, which could benefit from simple solution-processing of the active layer. The discovery of semiconductive polyacetylene by Heeger et al. in the late 1970s was a milestone towards the use of organic materials in electronics; the development of efficient protocols for the palladium catalyzed alkynylation reactions and the new conception of steric and conformational advantages of acetylenes have been recently focused the attention on conjugated triple-bond containing systems as a promising class of semiconductors for OPVs applications. We review here the most important and representative (poly)arylacetylenes that have been used in the field. A general introduction to (poly)arylacetylenes, and the most common synthetic approaches directed toward making these materials will be firstly given. After a brief discussion on working principles and critical parameters of OPVs, we will focus on molecular arylacetylenes, (co)polymers containing triple bonds, and metallopolyyne polymers as p-type semiconductor materials. The last section will deal with hybrids in which oligomeric/polymeric structures incorporating acetylenic linkages such as phenylene ethynylenes have been attached onto C(60), and their use as the active materials in photovoltaic devices.

  5. Temperature-dependent high resolution absorption cross sections of propane

    NASA Astrophysics Data System (ADS)

    Beale, Christopher A.; Hargreaves, Robert J.; Bernath, Peter F.

    2016-10-01

    High resolution (0.005 cm-1) absorption cross sections have been measured for pure propane (C3H8). These cross sections cover the 2550-3500 cm-1 region at five temperatures (from 296 to 700 K) and were measured using a Fourier transform spectrometer and a quartz cell heated by a tube furnace. Calibrations were made by comparison to the integrated cross sections of propane from the Pacific Northwest National Laboratory. These are the first high resolution absorption cross sections of propane for the 3 μm region at elevated temperatures. The cross sections provided may be used to monitor propane in combustion environments and in astronomical sources such as the auroral regions of Jupiter, brown dwarfs and exoplanets.

  6. 2. View of Liquified Propane Air Plant (New), former Exhaust ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    2. View of Liquified Propane Air Plant (New), former Exhaust and Compressor Building and former Purifying Plant in background. - Concord Gas Light Company, South Main Street, Concord, Merrimack County, NH

  7. 46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Methyl acetylene-propadiene mixture. 151.50-79 Section... acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must... acetylene-propadiene mixture must have a refrigeration system that does not compress the cargo vapor or...

  8. 46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Methyl acetylene-propadiene mixture. 151.50-79 Section... acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must... acetylene-propadiene mixture must have a refrigeration system that does not compress the cargo vapor or...

  9. 46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Methyl acetylene-propadiene mixture. 151.50-79 Section... acetylene-propadiene mixture. (a) The composition of the methyl acetylene-propadiene mixture at loading must... acetylene-propadiene mixture must have a refrigeration system that does not compress the cargo vapor or...

  10. Ethylene insensitive plants

    DOEpatents

    Ecker, Joseph R.; Nehring, Ramlah; McGrath, Robert B.

    2007-05-22

    Nucleic acid and polypeptide sequences are described which relate to an EIN6 gene, a gene involved in the plant ethylene response. Plant transformation vectors and transgenic plants are described which display an altered ethylene-dependent phenotype due to altered expression of EIN6 in transformed plants.

  11. Characterization of the Initial Reactions during the Cometabolic Oxidation of Methyl tert-Butyl Ether by Propane-Grown Mycobacterium vaccae JOB5

    PubMed Central

    Smith, Christy A.; O'Reilly, Kirk T.; Hyman, Michael R.

    2003-01-01

    The initial reactions in the cometabolic oxidation of the gasoline oxygenate, methyl tert-butyl ether (MTBE), by Mycobacterium vaccae JOB5 have been characterized. Two products, tert-butyl formate (TBF) and tert-butyl alcohol (TBA), rapidly accumulated extracellularly when propane-grown cells were incubated with MTBE. Lower rates of TBF and TBA production from MTBE were also observed with cells grown on 1- or 2-propanol, while neither product was generated from MTBE by cells grown on casein-yeast extract-dextrose broth. Kinetic studies with propane-grown cells demonstrated that TBF is the dominant (≥80%) initial product of MTBE oxidation and that TBA accumulates from further biotic and abiotic hydrolysis of TBF. Our results suggest that the biotic hydrolysis of TBF is catalyzed by a heat-stable esterase with activity toward several other tert-butyl esters. Propane-grown cells also oxidized TBA, but no further oxidation products were detected. Like the oxidation of MTBE, TBA oxidation was fully inhibited by acetylene, an inactivator of short-chain alkane monooxygenase in M. vaccae JOB5. Oxidation of both MTBE and TBA was also inhibited by propane (Ki = 3.3 to 4.4 μM). Values for Ks of 1.36 and 1.18 mM and for Vmax of 24.4 and 10.4 nmol min−1 mg of protein−1 were derived for MTBE and TBA, respectively. We conclude that the initial steps in the pathway of MTBE oxidation by M. vaccae JOB5 involve two reactions catalyzed by the same monooxygenase (MTBE and TBA oxidation) that are temporally separated by an esterase-catalyzed hydrolysis of TBF to TBA. These results that suggest the initial reactions in MTBE oxidation by M. vaccae JOB5 are the same as those that we have previously characterized in gaseous alkane-utilizing fungi. PMID:12570997

  12. Selective hydrogenation of acetylene on SiO2 supported Ni-In bimetallic catalysts: Promotional effect of In

    NASA Astrophysics Data System (ADS)

    Chen, Yanjun; Chen, Jixiang

    2016-11-01

    Ni/SiO2 and the bimetallic NixIn/SiO2 catalysts with different Ni/In ratios were tested for the selective hydrogenation of acetylene, and their physicochemical properties before and after the reaction were characterized by means of N2-sorption, H2-TPR, XRD, TEM, XPS, H2 chemisorption, C2H4-TPD, NH3-TPD, FT-IR of adsorbed pyridine, and TG/DTA and Raman. A promotional effect of In on the performance of Ni/SiO2 was found, and NixIn/SiO2 with a suitable Ni/In ratio gave much higher acetylene conversion, ethylene selectivity and catalyst stability than Ni/SiO2. This is ascribed to the geometrical isolation of the reactive Ni atoms with the inert In ones and the charge transfer from the In atoms to Ni ones, both of which are favorable for reducing the adsorption strength of ethylene and restraining the Csbnd C hydrogenolysis and the polymerizations of acetylene and the intermediate compounds. On the whole, Ni6In/SiO2 and Ni10In/SiO2 had better performance. Nevertheless, with increasing the In content, the selectivity to the C4+ hydrocarbons tended to increase due to the enhanced catalyst acidity because of the charge transfer from the In atoms to Ni ones. As the Lewis acid ones, the In sites could promote the polymerization. The catalyst deactivation was also analyzed. We propose that the Ni/SiO2 deactivation is mainly attributed to the phase change from metallic Ni to nickel carbide. The introduction of In inhibited the formation of nickel carbide. However, as the In content increased, the carbonaceous deposit became the main reason for the NixIn/SiO2 deactivation due to the enhanced catalyst acidity.

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

    USGS Publications Warehouse

    Culbertson, Charles W.; Zehnder, Alexander J. B.; Oremland, Ronald S.

    1981-01-01

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2.

  14. Anaerobic Oxidation of Acetylene by Estuarine Sediments and Enrichment Cultures

    PubMed Central

    Culbertson, Charles W.; Zehnder, Alexander J. B.; Oremland, Ronald S.

    1981-01-01

    Acetylene disappeared from the gas phase of anaerobically incubated estuarine sediment slurries, and loss was accompanied by increased levels of carbon dioxide. Acetylene loss was inhibited by chloramphenicol, air, and autoclaving. Addition of 14C2H2 to slurries resulted in the formation of 14CO2 and the transient appearance of 14C-soluble intermediates, of which acetate was a major component. Acetylene oxidation stimulated sulfate reduction; however, sulfate reduction was not required for the loss of C2H2 to occur. Enrichment cultures were obtained which grew anaerobically at the expense of C2H2. PMID:16345714

  15. Interpenetrating polymer networks from acetylene terminated materials

    NASA Technical Reports Server (NTRS)

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

    1989-01-01

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

  16. Reactions of Acetylene in Superbasic Media

    NASA Astrophysics Data System (ADS)

    Trofimov, Boris A.

    1981-02-01

    The results of studies of fundamentally new reactions of acetylene and its substituted derivatives in media of very high basicity are surveyed. They lead to hitherto unknown or relatively inaccessible monomers, reagents, and intermediates: 2-vinyloxybuta-1,3-diene, pyrroles, and N-vinylpyrroles, divinyl sulphide, divinyl telluride, 4-methylene-1,3-oxathiolan, di(buta-1,3-dienyl)sulphide, dihydrothiophen, 1-vinyl-2-thiabicyclo[3,2,0]hept-3-ene, etc. The most important properties of superbasic media consisting of an alkali metal hydroxide and a dipolar aprotic solvent as well as the probable mechanisms of their activating effect on anions and the triple bond are examined. An attempt is made to analyse these reactions in terms of coordination catalysis by alkali metal cations. The bibliography includes 199 references.

  17. High pressure chemistry of substituted acetylenes

    SciTech Connect

    Chellappa, Raja; Dattelbaum, Dana; Sheffield, Stephen; Robbins, David

    2011-01-25

    High pressure in situ synchrotron x-ray diffraction experiments were performed on substituted polyacetylenes: tert-butyl acetylene [TBA: (CH{sub 3}){sub 3}-C{triple_bond}CH] and ethynyl trimethylsilane [ETMS: (CH{sub 3}){sub 3}-Si{triple_bond}CH] to investigate pressure-induced chemical reactions. The starting samples were the low temperature crystalline phases which persisted metastably at room temperature and polymerized beyond 11 GPa and 26 GPa for TBA and ETMS respectively. These reaction onset pressures are considerably higher than what we observed in the shockwave studies (6.1 GPa for TBA and 6.6 GPa for ETMS). Interestingly, in the case of ETMS, it was observed with fluid ETMS as starting sample, reacts to form a semi-crystalline polymer (crystalline domains corresponding to the low-T phase) at pressures less than {approx}2 GPa. Further characterization using vibrational spectroscopy is in progress.

  18. A Detailed Modeling Study of Propane Oxidation

    SciTech Connect

    Westbrook, C K; Jayaweera, T M; Pitz, W J; Curran, H J

    2004-03-19

    A detailed chemical kinetic mechanism has been used to simulate ignition delay times recorded by a number of experimental shock tube studies over the temperature range 900 {le} T {le} 1800 K, in the pressure range 0.75-40 atm and in the equivalence ratio range 0.5 {le} {phi} {le} 2.0. Flame speed measurements at 1 atm in the equivalence ratio range 0.4 {le} {phi} {le} 1.8 have also been simulated. Both of these data sets, particularly those recorded at high pressure, are of particular importance in validating a kinetic mechanism, as internal combustion engines operate at elevated pressures and temperatures and rates of fuel oxidation are critical to efficient system operation. Experiments in which reactant, intermediate and product species were quantitatively recorded, versus temperature in a jet-stirred reactor (JSR) and versus time in a flow reactor are also simulated. This data provide a stringent test of the kinetic mechanism as it must reproduce accurate quantitative profiles for all reactant, intermediate and product species. The JSR experiments were performed in the temperature range 1000-1110 K, in the equivalence ratio range 0.5 {le} {phi} {le} 4.0, at a pressure of 5 atm. These experiments are complemented by those carried out in a flow reactor in the temperature range 660-820 K, at 10 atm and at an equivalence ratio of 0.4. In addition, burner stabilized flames were simulated, where chemical species profiles were measured at atmospheric pressure for two propane-air flat flames. Overall, reasonably good agreement is observed between the model simulations and the experimental results.

  19. New Formulation for the Viscosity of Propane

    NASA Astrophysics Data System (ADS)

    Vogel, Eckhard; Herrmann, Sebastian

    2016-12-01

    A new viscosity formulation for propane, using the reference equation of state for its thermodynamic properties by Lemmon et al. [J. Chem. Eng. Data 54, 3141 (2009)] and valid in the fluid region from the triple-point temperature to 650 K and pressures up to 100 MPa, is presented. At the beginning, a zero-density contribution and one for the critical enhancement, each based on the experimental data, were independently generated in parts. The higher-density contributions are correlated as a function of the reciprocal reduced temperature τ = Tc/T and of the reduced density δ = ρ/ρc (Tc—critical temperature, ρc—critical density). The final formulation includes 17 coefficients inferred by applying a state-of-the-art linear optimization algorithm. The evaluation and choice of the primary data sets are detailed due to its importance. The viscosity at low pressures p ≤ 0.2 MPa is represented with an expanded uncertainty of 0.5% (coverage factor k = 2) for temperatures 273 ≤ T/K ≤ 625. The expanded uncertainty in the vapor phase at subcritical temperatures T ≥ 273 K as well as in the supercritical thermodynamic region T ≤ 423 K at pressures p ≤ 30 MPa is assumed to be 1.5%. In the near-critical region (1.001 < 1/τ < 1.010 and 0.8 < δ < 1.2), the expanded uncertainty increases with decreasing temperature up to 3.0%. It is further increased to 4.0% in regions of less reliable primary data sets and to 6.0% in ranges in which no primary data are available but the equation of state is valid. Tables of viscosity computed for the new formulation are given in an Appendix for the single-phase region, for the vapor-liquid phase boundary, and for the near-critical region.

  20. Nitrogen fixation (acetylene reduction) by annual winter legumes on a coal surface mine

    SciTech Connect

    Gabrielson, F.C.

    1982-01-01

    The winter annuals, crimson clover, rose clover, subterranean clover and hairy vetch, were evaluated for their ability to fix nitrogen on coal surface mine substrates by measuring their ability to reduce acetylene to ethylene. The effects of fertilizer, Abruzzi ryegrass, Kentucky 31 fescue grass and a phytotoxic plant Chenopodium album on nitrogen fixation was also assessed. Crimson clover was recommended as the best legume to use on topsoil and shale in the South. Hairy vetch gave good results on shale and subterranean clover did well on topsoil. The use of these species for revegetation is discussed. Overall, no correlation between substrate pH and ethylene levels was found and effects of substrate depended upon the legume species. Super phosphate fertilizer supported less nitrogen fixation than 13-13-13. Abruzzi ryegrass in some unknown way inhibited plant density and nitrogen fixation by legumes but not by free living substrate micro-organisms. Shale from under dead Chenopodium plants in both field and greenhouse experiments did not inhibit nitrogen fixation. 11 references, 7 tables.

  1. Nitrogen fixation (Acetylene Reduction) by annual winter legumes on a coal surface mine

    SciTech Connect

    Gabrielson, F.C.

    1982-01-01

    The winter annuals, crimson clover, rose clover, subterranean clover and hairy vetch, were evaluated for nitrogen fixing capacity on coal surface mine substrates by measuring their ability to reduce acetylene to ethylene. The effects of fertilizer, Abruzzi rye, Kentucky 31 fescue grass and a phytotoxic plant Chenopodium album on nitrogen fixation were also assessed. Crimson clover was recommended as the best legume to use on topsoil and shale in the south. Hairy vetch gave good results on shale and subterranean clover did well on topsoil. The use of these species for revegetation is discussed. Overall, no correlation between substrate pH and ethylene levels was found and effects of substrate depended upon the legume species. Super phosphate fertilizer supported less nitrogen fixation than 13-13-13. Abruzzi rye in some unknown way inhibited plant density and nitrogen fixation by legumes but not by free living substrate micro-organisms. Shale from under dead Chenopodium plants in both field and greehouse experiments did not inhibit nitrogen fixation. 7 tables.

  2. On the ionic states of vinylidene and acetylene

    NASA Astrophysics Data System (ADS)

    Rosmus, P.; Botchwina, P.; Maier, J. P.

    1981-11-01

    Electronic states of C 2H +2 cation (with acetylenic and vinylidenic structure) are investigated by ab initio SCF and PNO CEPA calculations. The lowest excited state of the acetylene cation is calculated to be 4A 2 in a strongly bent cis conformation, and a qualitative explanation is given for the lack of detectable emission from theà 2∑ g+ state. Only the radical anion with the vinylidenic structure is bound.

  3. Ethylene by Naphta Cracking

    ERIC Educational Resources Information Center

    Wiseman, Peter

    1977-01-01

    Presents a discussion of the manufacture of ethylene by thermal cracking of hydrocarbon feedstocks that is useful for introducing the subject of industrial chemistry into a chemistry curriculum. (MLH)

  4. The TNT equivalence of an optimum propane oxygen mixture

    NASA Astrophysics Data System (ADS)

    Dewey, J. M.

    2005-12-01

    Measurements of the times of arrival of the primary shock produced by the explosion of a nominal 20 tn propane-oxygen mixture have been analysed to provide the variation of the peak hydrostatic overpressure as a function of distance. The results have been scaled to those for a charge of unit mass at normal temperature and pressure, based on the masses of the propane and oxygen and of the propane alone. The scaled results are compared with those produced by the explosion of a hemispherical unit mass of TNT to provide the TNT equivalence factor as a function of overpressure and distance. For overpressures greater than 1 atm there is a strong dependence on the distance from the centre of the explosion, but at lower overpressures the equivalence factors have almost constant values of 0.55 for the propane-oxygen mixture and 1.95 for the propane alone. The significance of these findings, in relationship to vapour cloud explosions and boiling liquid expanding vapour explosions, is discussed.

  5. Ethylene-Vapor Optrodes

    NASA Technical Reports Server (NTRS)

    Tabacco, Mary Beth; Zhou, Quan

    1993-01-01

    Porous optical fibers include sensing regions filled with reagents. Optical-fiber chemical sensors (optrodes) developed to measure concentrations of ethylene in air in enclosed artificial plant-growth environments. Such measurements needed because ethylene acts as plant-growth hormone affecting growth at concentrations less than or equal to 20 parts per billion. Optrodes small, but exhibit sensitivities comparable to those of larger instruments. Operated safely in potentially explosive atmospheres and neither cause, nor susceptible to, electrical interference at suboptical frequencies.

  6. Satellite observations of ethylene

    NASA Astrophysics Data System (ADS)

    Dolan, W.; Payne, V.; Kulawik, S. S.; Bowman, K. W.

    2015-12-01

    Ethylene (C2H4) is a trace gas commonly associated with boreal fire plumes and the petrochemical industry. It has a short lifetime (~1-2 days) in the troposphere due to its reaction with OH. Chemical destruction of ethylene in the atmosphere leads to the production of ozone precursors such as carbon monoxide (CO) and formaldehyde. The Tropospheric Emission Spectrometer (TES) is a Fourier Transform Spectrometer aboard the Aura satellite that measures thermal infrared radiances with high spectral resolution. Trace gas products retrieved routinely from TES spectra include O3, CO, H2O, HDO, CH4, NH3, HCOOH, CH3OH, with OCS and PAN to be included in the next data release. The TES spectra also includes a wealth of untapped information about other trace gasses including ethylene. Ethylene was first observed in TES spectra by Alvarado et al. (2011), though it has yet to be developed into an operational product. Our study focuses on the detection and initial quantitative estimates of ethylene in TES special observations taken in support of the 2008 ARCTAS mission. Initial observations of HCN in the spectra may provide a way to distinguish between fire plume and petrochemical derived ethylene. Results indicate a correlation between ethylene and CO in fresh fire plumes but not in older plumes, consistent with the gas's short lifetime. The approach adopted here to detect ethylene in the TES 2008 ARCTAS special observations can easily be expanded to larger datasets, including those from other thermal infrared sounders as well as to other trace gases.

  7. Inspecting an ethylene pipe line

    SciTech Connect

    Ramsvig, D.M. ); Duncan, J.; Zillinger, L. )

    1991-07-01

    This paper reports on the Alberta Gas Ethylene Co. (AGEC), completion of intensive internal cleaning and inspection program on their 112-mi ethylene pipe line. AGEC operates two ethylene manufacturing facilities in central Alberta, Canada. The ethylene plants are located 12.4 mi east of Red Deer, Alta., at Joffre, and supply two customers in Joffre. The remaining ethylene is shipped by the 112-mi, 12-in. line to a storage cavern near Edmonton.

  8. Acetylene adsorption on δ-MoC(001), TiC(001) and ZrC(001) surfaces: a comprehensive periodic DFT study.

    PubMed

    Jimenez-Orozco, Carlos; Florez, Elizabeth; Moreno, Andres; Liu, Ping; Rodriguez, Jose A

    2017-01-04

    A comprehensive study of acetylene adsorption on δ-MoC(001), TiC(001) and ZrC(001) surfaces was carried out by means of calculations based on periodic density functional theory, using the Perdew-Burke-Ernzerhof exchange-correlation functional. It was found that the bonding of acetylene was significantly affected by the electronic and structural properties of the carbide surfaces. The adsorbate interacted with metal and/or carbon sites of the carbide. The interaction of acetylene with the TiC(001) and ZrC(001) surfaces was strong (binding energies higher than -3.5 eV), while moderate acetylene adsorption energies were observed on δ-MoC(001) (-1.78 eV to -0.66 eV). Adsorption energies, charge density difference plots and Mulliken charges suggested that the binding of the hydrocarbon to the surface had both ionic and covalent contributions. According to the C-C bond lengths obtained, the adsorbed molecule was modified from acetylene-like into ethylene-like on the δ-MoC(001) surface (desired behavior for hydrogenation reactions) but into ethane-like on TiC(001) and ZrC(001). The obtained results suggest that the δ-MoC(001) surface is expected to have the best performance in selective hydrogenation reactions to convert alkynes into alkenes. Another advantage of δ-MoC(001) is that, after C2H2 adsorption, surface carbon sites remain available, which are necessary for H2 dissociation. However, these sites were occupied when C2H2 was adsorbed on TiC(001) and ZrC(001), limiting their application in the hydrogenation of alkynes.

  9. An engineered pathway for the biosynthesis of renewable propane.

    PubMed

    Kallio, Pauli; Pásztor, András; Thiel, Kati; Akhtar, M Kalim; Jones, Patrik R

    2014-09-02

    The deployment of next-generation renewable biofuels can be enhanced by improving their compatibility with the current infrastructure for transportation, storage and utilization. Propane, the bulk component of liquid petroleum gas, is an appealing target as it already has a global market. In addition, it is a gas under standard conditions, but can easily be liquefied. This allows the fuel to immediately separate from the biocatalytic process after synthesis, yet does not preclude energy-dense storage as a liquid. Here we report, for the first time, a synthetic metabolic pathway for producing renewable propane. The pathway is based on a thioesterase specific for butyryl-acyl carrier protein (ACP), which allows native fatty acid biosynthesis of the Escherichia coli host to be redirected towards a synthetic alkane pathway. Propane biosynthesis is markedly stimulated by the introduction of an electron-donating module, optimizing the balance of O2 supply and removal of native aldehyde reductases.

  10. An engineered pathway for the biosynthesis of renewable propane

    PubMed Central

    Kallio, Pauli; Pásztor, András; Thiel, Kati; Akhtar, M. Kalim; Jones, Patrik R.

    2014-01-01

    The deployment of next-generation renewable biofuels can be enhanced by improving their compatibility with the current infrastructure for transportation, storage and utilization. Propane, the bulk component of liquid petroleum gas, is an appealing target as it already has a global market. In addition, it is a gas under standard conditions, but can easily be liquefied. This allows the fuel to immediately separate from the biocatalytic process after synthesis, yet does not preclude energy-dense storage as a liquid. Here we report, for the first time, a synthetic metabolic pathway for producing renewable propane. The pathway is based on a thioesterase specific for butyryl-acyl carrier protein (ACP), which allows native fatty acid biosynthesis of the Escherichia coli host to be redirected towards a synthetic alkane pathway. Propane biosynthesis is markedly stimulated by the introduction of an electron-donating module, optimizing the balance of O2 supply and removal of native aldehyde reductases. PMID:25181600

  11. Ab initio calculations of one-electron-scattering properties of ethyne (acetylene) and ethylene molecules

    SciTech Connect

    Tripathi, A.N.; Smith, V.H. Jr. K7L3N6); Kaijser, P.; Siemens, A.G. ); Diercksen, G.H.F. )

    1990-03-01

    Isotropic scattering functions and Compton profiles together with their directional components for several directions relevant to the molecular structure of C{sub 2}H{sub 2} and C{sub 2}H{sub 4} have been evaluated for {ital ab} {ital initio} self-consistent field and configuration-interaction wave functions. The internally folded density (reciprocal form factor) {ital B}({ital r}) is calculated and discussed as are various momentum expectation values. Comparison is made with available experimental and other theoretical results.

  12. Oxidative dehydrogenation of propane over Mg-Mo-O catalysts

    SciTech Connect

    Cadus, L.E.; Abello, M.C.; Gomez, M.F.; Rivarola, J.B.

    1996-01-01

    Mg-Mo-O catalysts have been investigated with different techniques (XRD, XPS, IR, and EPR spectroscopies) in order to explain the difference in catalytic behavior in the oxidative dehydrogenation of propane to propene. The active site would be a coordinatively unsaturated form of Mo{sup 5+}. The active Mo{sup 5+} could be generated on the surface by propane reduction. The slight excess of MoO{sub 3} which is necessary for the catalyst to become an active one probably contributes to the formation of Mo{sup 5+}.

  13. Acetylene on Titan’s Surface

    NASA Astrophysics Data System (ADS)

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

    2016-09-01

    Titan’s atmosphere is opaque in the near-infrared due to gaseous absorptions, mainly by methane, and scattering by aerosols, except in a few “transparency windows.” Thus, the composition of Titan’s surface remains difficult to access from space and is still poorly constrained. Photochemical models suggest that most of the organic compounds formed in the atmosphere are heavy enough to condense and build up at the surface in liquid and solid states over geological timescales. Acetylene (C2H2) net production in the atmosphere is predicted to be larger than any other compound and C2H2 has been speculated to exist on the surface of Titan. C2H2 was detected as a trace gas sublimated/evaporated from the surface using the Gas Chromatograph Mass Spectrometer after the landing of the Huygens probe. Here we show evidence of C2H2 on the surface of Titan by detecting absorption bands at 1.55 and 4.93 μm using the Cassini Visual and Infrared Mapping Spectrometer at three different equatorial areas—Tui Regio, eastern Shangri La, and Fensal-Aztlan/Quivira. We found that C2H2 is preferentially detected in low-albedo areas, such as sand dunes and near the Huygens landing site. The specific location of the C2H2 detections suggests that C2H2 is mobilized by surface processes, such as surface weathering by liquids through dissolution/evaporation processes.

  14. Ion-induced dissociation dynamics of acetylene

    SciTech Connect

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

    2008-02-15

    We report on the results of dissociation dynamics of multiple charged acetylene molecules formed in collision with 1.2 MeV Ar{sup 8+} projectiles. Using the coincidence map, we can separate out the different dissociation pathways between carbon and hydrogen ionic fragments as well as complete two-body breakup events. From the measured slopes of the coincidence islands for carbon atomic fragments and theoretical values determined from the charge and momentum distribution of the correlated particles, we observe a diatom like behavior of the C-C charged complex during dissociation of multiply charged C{sub 2}H{sub 2}. We conclude that this behavior in breakup dynamics is a signature of sequentiality in dissociation of this multiply charged molecular species. The shape and orientation of the islands give further information about the momentum balance in the fragmentation process of two- or many-body dissociation pathways. Kinetic energy release of different breakup channels are reported here and compared with values calculated from the pure Coulomb explosion model.

  15. Three new olanzapine structures: the acetic acid monosolvate, and the propan-2-ol and propan-2-one hemisolvate monohydrates.

    PubMed

    Bojarska, Joanna; Maniukiewicz, Waldemar; Sieroń, Lesław

    2013-07-01

    The crystal structures of three new solvates of olanzapine [systematic name: 2-methyl-4-(4-methylpiperazin-1-yl)-10H-thieno[2,3-b][1,5]benzodiazepine], namely olanzapine acetic acid monosolvate, C17H20N4S·C2H4O2, (I), olanzapine propan-2-ol hemisolvate monohydrate, C17H20N4S·0.5C3H8O·H2O, (II), and olanzapine propan-2-one hemisolvate monohydrate, C17H20N4S·0.5C3H6O·H2O, (III), are presented and compared with other known olanzapine forms. There is a fairly close resemblance of the molecular conformation for all studied analogues. The crystal structures are built up through olanzapine dimers, which are characterized via C-H...π interactions between the aliphatic fragment (1-methylpiperazin-4-yl) and the aromatic fragment (benzene system). All solvent (guest) molecules participate in hydrogen-bonding networks. The crystal packing is sustained via intermolecular N(host)-H···O(guest), O(guest)-H···N(host), O(guest)-H···O(guest) and C(host)-H···O(guest) hydrogen bonds. It should be noted that the solvent propan-2-ol in (II) and propan-2-one in (III) show orientational disorder. The propan-2-ol molecule lies close to a twofold axis, while the propan-2-one molecule resides strictly on a twofold axis through the carbonyl C atom. In both cases, the water molecules present positional disorder of the H atoms.

  16. Preparation of ethylene gas and comparison of ethylene responses induced by ethylene, ACC, and ethephon.

    PubMed

    Zhang, Wei; Wen, Chi-Kuang

    2010-01-01

    Ethylene is a gaseous plant hormone used in many physiological studies examining its role in plant growth and development. However, ethylene gas may not be conveniently available to many laboratories for occasional use, and therefore several chemicals can be used as replacements. Here we report that the kinetics of the ethylene response induced by ethylene and two widely-used ethylene replacements are different. ACC failed to efficiently replace prolonged ethylene treatments, while the decomposition products of ethephon may cause non-specific responses and the efficiency of ethephon conversion to ethylene was relatively low. A cost-effective method to prepare ethylene gas was developed. Analyzed by gas chromatography, the chemically produced ethylene exhibited an identical chromatogram to that from the commercial source. Our synthetic ethylene gave the same dose-response curve in Arabidopsis as gaseous ethylene. Our study shows that the use of the ethylene gas is essential to experiments that are sensitive to treatment duration and dosage. When ACC and ethephon are used as replacements, caution should be taken in the experimental design. For laboratories that do not have an ethylene tank, ethylene gas can be easily prepared by a chemical approach without further purification.

  17. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  18. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  19. 40 CFR 721.10339 - Adipic acid, substituted propane, alkyldiol, acrylate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Adipic acid, substituted propane... Significant New Uses for Specific Chemical Substances § 721.10339 Adipic acid, substituted propane, alkyldiol... substance identified generically as adipic acid, substituted propane, alkyldiol, acrylate (PMN P-04-113)...

  20. Zeolitic imidazolate frameworks for kinetic separation of propane and propene

    DOEpatents

    Li, Jing; Li, Kunhao; Olson, David H.

    2014-08-05

    Zeolitic Imidazolate Frameworks (ZIFs) characterized by organic ligands consisting of imidazole ligands that are either essentially all 2-chloroimidazole ligands or essentially all 2-bromoimidazole ligands are disclosed. Methods for separating propane and propene with the ZIFs of the present invention, as well as other ZIFs, are also disclosed.

  1. Recovery and purification of ethylene

    DOEpatents

    Reyneke, Rian; Foral, Michael J.; Lee, Guang-Chung; Eng, Wayne W. Y.; Sinclair, Iain; Lodgson, Jeffery S.

    2008-10-21

    A process for the recovery and purification of ethylene and optionally propylene from a stream containing lighter and heavier components that employs an ethylene distributor column and a partially thermally coupled distributed distillation system.

  2. Turbine Engine Exhaust Hydrocarbon Analysis. Task 1 and 2

    DTIC Science & Technology

    1983-06-01

    outlet) Ethane , Ethylene Cryogenic/g.c. 2995 2860 Acety1en Propene 369 359 Propane 516 503 i-Butane 402 390 n-Butane 1900 1850 t-2-Butene 637 607... Ethylene 91 101 93 (d) Acetylene 93 100 94 d) Provene 104 108 98 102 Propane 104 110 109 102 I-Butane 102 100 109 100 n-Butane 100 100 100 100 t-2...Analytical of Found Compound Method Determinations ppbC Z RSD Ethane Cryogenic/g.c. 4 700 2.1 Ethylene 4 1220 3.0 Propene 4 508 1.6 Acetylene 4 980 2.7 i

  3. The Synthesis and Isothermal Aging Behavior of Oxygen-Free Acetylene Terminated Quinoxalines

    DTIC Science & Technology

    1981-05-01

    AFWAL-TR-81-4004 THE SYNTHESIS AND ISOTHERMAL AGING BEHAVIOR OF OXYGEN-FREE ACETYLENE TERMINATED QUINOXALINES Polymer Branch Nonmetallic Materials...TYPE OF REPORT & PERIOD COVERED THE SYNTHESIS AND ISOTHERMAL AGING BEHAVIOR Final Technical Report OF OXYGEN-FREE ACETYLENE TERMINATED January 1979...Quinoxaline Acetylene Terminated Acetylene Cure Thermooxidative Stability Isothermal Aging 20. ABSTRACT (Continue on reverse side if necessary and identify by

  4. Acetylene hydratase: a non-redox enzyme with tungsten and iron-sulfur centers at the active site.

    PubMed

    Kroneck, Peter M H

    2016-03-01

    In living systems, tungsten is exclusively found in microbial enzymes coordinated by the pyranopterin cofactor, with additional metal coordination provided by oxygen and/or sulfur, and/or selenium atoms in diverse arrangements. Prominent examples are formate dehydrogenase, formylmethanofuran dehydrogenase, and aldehyde oxidoreductase all of which catalyze redox reactions. The bacterial enzyme acetylene hydratase (AH) stands out of its class as it catalyzes the conversion of acetylene to acetaldehyde, clearly a non-redox reaction and a reaction distinct from the reduction of acetylene to ethylene by nitrogenase. AH harbors two pyranopterins bound to W, and a [4Fe-4S] cluster. W is coordinated by four dithiolene sulfur atoms, one cysteine sulfur, and one oxygen ligand. AH activity requires a strong reductant suggesting W(IV) as the active oxidation state. Two different types of reaction pathways have been proposed. The 1.26 Å structure reveals a water molecule coordinated to W which could gain a partially positive net charge by the adjacent protonated Asp-13, enabling a direct attack of C2H2. To access the W-Asp site, a substrate channel was evolved distant from where it is found in other members of the DMSOR family. Computational studies of this second shell mechanism led to unrealistically high energy barriers, and alternative pathways were proposed where C2H2 binds directly to W. The architecture of the catalytic cavity, the specificity for C2H2 and the results from site-directed mutagenesis do not support this first shell mechanism. More investigations including structural information on the binding of C2H2 are needed to present a conclusive answer.

  5. Current Toxicology of Ethylene Oxide,

    DTIC Science & Technology

    1982-12-01

    carcinogenicity are presented. The overall toxicological implications and a recommendation on the use of ethylene oxide are briefly discussed. (U...wer exposed to ethylene oxide vapour. A single exposure of the male rats to vapour at 100 ppm for 4 hours resulted in reproduction A abnormalities...oxide causes leukemia. It should be noted also that ethylene oxide in the presence of water produces ethylene glycol. Subchronic and chronic exposures

  6. Identification of Acetylene on Titan's Surface

    NASA Astrophysics Data System (ADS)

    Singh, S.; McCord, T. B.; Rodriguez, S.; Combe, J. P.; Cornet, T.; Le Mouelic, S.; Maltagliati, L.; Chevrier, V.; Clark, R. N.

    2015-12-01

    Titan's atmosphere is opaque in the near infrared due to gaseous absorptions, mainly by methane, and scattering by aerosols, except in a few "transparency windows" (e.g., Sotin et al., 2005). Thus, the composition of Titan surface remains difficult to access from space and is still poorly constrained, limited to ethane in the polar lakes (Brown et al., 2008) and a few possible organic molecules on the surface (Clark et al., 2010). Photochemical models suggest that most of the organic compounds formed in the atmosphere are heavy enough to condense and build up at the surface in liquid and solid states over geological timescale (Cordier et al., 2009, 2011). Acetylene (C2H2) is one of the most abundant organic molecules in the atmosphere and thus thought to present on the surface as well. Here we report direct evidence of solid C2H2 on Titan's surface using Cassini Visual and Infrared Mapping Spectrometer (VIMS) data. By comparing VIMS observations and laboratory measurements of solid and liquid C2H2, we identify a specific absorption at 1.55 µm that is widespread over Titan but is particularly strong in the brightest terrains. This surface variability suggests that C2H2 is mobilized by surface processes, such as surface weathering, topography, and dissolution/evaporation. The detection of C2H2 on the surface of Titan opens new paths to understand and constrain Titan's surface activity. Since C2H2 is highly soluble in Titan liquids (Singh et al. 2015), it can easily dissolve in methane/ethane and may play an important role in carving of fluvial channels and existence of karstic lakes at higher latitudes on Titan. These processes imply the existence of a dynamic surface with a continued history of erosion and deposition of C2H2 on Titan.

  7. Chemistry and properties of blends of acetylene terminated materials

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.

    1991-01-01

    As part of a NASA program to develop new high temperature/high performance structural materials, the chemistry and properties of acetylene-containing materials and their cured resins are under investigation. The objective of this work is to develop materials that are readily processable (i.e., 200-300 C and about 1.4 MPa or less) and possess usable mechanical properties at temperatures as high as 177 C. An acetylene-terminated aspartimide (ATA) was blended with an equal weight of an acetylene-terminated arylene ether (ATAE) oligomer. The blend was subsequently thermally cured to yield a resin which was evaluated in the form of neat resin moldings, adhesive specimens, and laminates. Adhesive specimens and laminates gave good mechanical properties to temperatures as high as 177 C. In addition, preliminary laminate work is presented on the resin from a blend of a new N-methyl substituted ATA and an ATAE.

  8. La-Activated Bicyclo-oligomerization of Acetylene to Naphthalene.

    PubMed

    Hewage, Dilrukshi; Silva, W Ruchira; Cao, Wenjin; Yang, Dong-Sheng

    2016-03-02

    We report the first example of metal-mediated acetylene bicyclopentamerization to form naphthalene in the gas phase. The bicyclic aromatic compound was observed in a complex with La. The La(naphthalene) complex was formed by the reaction of laser-ablated La atoms with acetylene molecules in a molecular beam source and was characterized by mass-analyzed threshold ionization spectroscopy. The bicyclo-oligomerization reaction occurs through sequential acetylene additions coupled with dehydrogenation. Three intermediates in the reaction have been identified: lanthanacyclopropene [La(C2H2)], La(cyclobut-1-en-3-yne) [La(C4H2)], and La(benzyne) [(La(C6H4)]. The metal-ligand bonding in the three intermediates is considerably different from that in the La(naphthalene) complex, as suggested by accurately measured adiabatic ionization energies.

  9. 46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping...

  10. 46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping...

  11. 46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping...

  12. 46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping...

  13. 46 CFR 56.50-103 - Fixed oxygen-acetylene distribution piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Fixed oxygen-acetylene distribution piping. 56.50-103... oxygen-acetylene distribution piping. (a) This section applies to fixed piping installed for the distribution of oxygen and acetylene carried in cylinders as vessels stores. (b) The distribution piping...

  14. Ethylene thiourea (ETU)

    Integrated Risk Information System (IRIS)

    Ethylene thiourea ( ETU ) ; CASRN 96 - 45 - 7 Human health assessment information on a chemical substance is included in the IRIS database only after a comprehensive review of toxicity data , as outlined in the IRIS assessment development process . Sections I ( Health Hazard Assessments for Noncarci

  15. The Application of Gas Dwell Time Control for Rapid Single Wall Carbon Nanotube Forest Synthesis to Acetylene Feedstock

    PubMed Central

    Matsumoto, Naoyuki; Oshima, Azusa; Sakurai, Shunsuke; Yamada, Takeo; Yumura, Motoo; Hata, Kenji; Futaba, Don N.

    2015-01-01

    One aspect of carbon nanotube (CNT) synthesis that remains an obstacle to realize industrial mass production is the growth efficiency. Many approaches have been reported to improve the efficiency, either by lengthening the catalyst lifetime or by increasing the growth rate. We investigated the applicability of dwell time and carbon flux control to optimize yield, growth rate, and catalyst lifetime of water-assisted chemical vapor deposition of single-walled carbon nanotube (SWCNT) forests using acetylene as a carbon feedstock. Our results show that although acetylene is a precursor to CNT synthesis and possesses a high reactivity, the SWCNT forest growth efficiency is highly sensitive to dwell time and carbon flux similar to ethylene. Through a systematic study spanning a wide range of dwell time and carbon flux levels, the relationship of the height, growth rate, and catalyst lifetime is found. Further, for the optimum conditions for 10 min growth, SWCNT forests with ~2500 μm height, ~350 μm/min initial growth rates and extended lifetimes could be achieved by increasing the dwell time to ~5 s, demonstrating the generality of dwell time control to highly reactive gases.

  16. Coke formation and its effect on internal mass transfer and selectivity in Pd-catalysed acetylene hydrogenation

    SciTech Connect

    Asplund, S.

    1996-01-01

    Catalyst aging by coke formation has been studied for the selective hydrogenation of acetylene in the presence of excess ethylene on supported palladium catalysts. Deposited coke was found to have a substantial influence on the effective diffusivity, which decreased about one order of magnitude during 100 h of operation. As has been observed previously the selectivity for the undesired ethane was higher on aged catalysts, while the activity for acetylene hydrogenation was almost constant. These effects, however, were strongly dependent on the catalyst particle size, although the behaviour of fresh catalysts was unaffected by mass transfer limitations. When the catalyst used was Pd/{alpha}-Al{sub 2}O{sub 3} the change in selectivity with aging could be explained solely as a consequence of the increased diffusion resistance. The mass transfer effects were important also on Pd/{gamma}-Al{sub 2}O{sub 3}, but on this catalyst there was an additional increase in ethane selectivity that could not be attributed to diffusion limitations. Calculations and experimental tests showed that the observed phenomena are relevant also for the shell-type catalysts normally used industrially. The coke formation itself was about four to five times faster on Pd/{gamma}-Al{sub 2}O{sub 3} compared to the {alpha}-Al{sub 2}O{sub 3}-supported catalyst. The coke was generally concentrated towards the pellet periphery showing the influence of diffusion resistance also on the coke-forming reactions. 27 refs., 10 figs., 5 tabs.

  17. How plants sense ethylene gas--the ethylene receptors.

    PubMed

    Lacey, Randy F; Binder, Brad M

    2014-04-01

    Ethylene is a hormone that affects many processes important for plant growth, development, and responses to stresses. The first step in ethylene signal transduction is when ethylene binds to its receptors. Numerous studies have examined how these receptors function. In this review we summarize many of these studies and present our current understanding about how ethylene binds to the receptors. The biochemical output of the receptors is not known but current models predict that when ethylene binds to the receptors, the activity of the associated protein kinase, CTR1 (constitutive triple response1), is reduced. This results in downstream transcriptional changes leading to ethylene responses. We present a model where a copper cofactor is required and the binding of ethylene causes the receptor to pass through a transition state to become non-signaling leading to lower CTR1 activity.

  18. Siloxane containing addition polyimides. II - Acetylene terminated polyimides

    NASA Technical Reports Server (NTRS)

    Maudgal, S.; St. Clair, T. L.

    1984-01-01

    Acetylene terminated polyimide oligomers having a range of molecular weights have been synthesized by reacting bis (gamma-aminopropyl) tetramethyldisiloxane, aminophenylacetylene and 3, 3', 4, 4' benzophenonetetracarboxylic dianhydride in different molar ratios. The prepolymers were isolated and characterized for melt flow and cure properties. They show promise as adhesives for bonding titanium to titanium and as matrix resins for graphite cloth reinforced composites. The most promising system has been blended in varying proportions with Thermid 600, a commercially available acetylene terminated polyimide oligomer, and the mixtures have been tested for application as composite matrix resins.

  19. Synthesis of functional acetylene derivatives from calcium carbide.

    PubMed

    Lin, Zhewang; Yu, Dingyi; Sum, Yin Ngai; Zhang, Yugen

    2012-04-01

    AHA Erlebnis: CaC(2), used to produce acetylene until several decades ago, is re-emerging as a cheap, sustainable resource synthesized from coal and lignocellulosic biomass. We report efficient catalytic protocols for the synthesis of functional acetylene derivatives from CaC(2) through aldehyde, alkyne, and amine (AAA) as well as alkyne, haloalkane, and amine (AHA) couplings, and in addition demonstrate its use in click and Sonogashira chemistry, showing that calcium carbide is a sustainable and cost-efficient carbon source.

  20. Ethylene Glycol Metabolism in the Acetogen Acetobacterium woodii

    PubMed Central

    Trifunović, Dragan; Schuchmann, Kai

    2016-01-01

    ABSTRACT The acetogenic bacterium Acetobacterium woodii is able to grow by the oxidation of diols, such as 1,2-propanediol, 2,3-butanediol, or ethylene glycol. Recent analyses demonstrated fundamentally different ways for oxidation of 1,2-propanediol and 2,3-butanediol. Here, we analyzed the metabolism of ethylene glycol. Our data demonstrate that ethylene glycol is dehydrated to acetaldehyde, which is then disproportionated to ethanol and acetyl coenzyme A (acetyl-CoA). The latter is further converted to acetate, and this pathway is coupled to ATP formation by substrate-level phosphorylation. Apparently, the product ethanol is in part further oxidized and the reducing equivalents are recycled by reduction of CO2 to acetate in the Wood-Ljungdahl pathway. Biochemical data as well as the results of protein synthesis analysis are consistent with the hypothesis that the propane diol dehydratase (PduCDE) and CoA-dependent propionaldehyde dehydrogenase (PduP) proteins, encoded by the pdu gene cluster, also catalyze ethylene glycol dehydration to acetaldehyde and its CoA-dependent oxidation to acetyl-CoA. Moreover, genes encoding bacterial microcompartments as part of the pdu gene cluster are also expressed during growth on ethylene glycol, arguing for a dual function of the Pdu microcompartment system. IMPORTANCE Acetogenic bacteria are characterized by their ability to use CO2 as a terminal electron acceptor by a specific pathway, the Wood-Ljungdahl pathway, enabling in most acetogens chemolithoautotrophic growth with H2 and CO2. However, acetogens are very versatile and can use a wide variety of different substrates for growth. Here we report on the elucidation of the pathway for utilization of ethylene glycol by the model acetogen Acetobacterium woodii. This diol is degraded by dehydration to acetaldehyde followed by a disproportionation to acetate and ethanol. We present evidence that this pathway is catalyzed by the same enzyme system recently described for the

  1. Microgravity Superagglomerates Produced By Silane And Acetylene

    NASA Technical Reports Server (NTRS)

    Gokoglu, Suleyman (Technical Monitor); Bundy, Matthew; Mulholland, George W.; Manzello, Samuel; Yang, Jiann; Scott, John Henry; Sivathanu, Yudaya

    2003-01-01

    The size of the agglomerates produced in the upper portion of a flame is important for a variety of applications. Soot particle size and density effect the amount of radiative heat transfer from a fire to its surroundings. Particle size determines the lifetime of smoke in a building or in the atmosphere, and exposure hazard for smoke inhaled and deposited in the lungs. The visibility through a smoke layer and dectectability of the smoke are also greatly affected by agglomerate size. Currently there is limited understanding of soot growth with an overall dimension of 10 m and larger. In the case of polystyrene, smoke agglomerates in excess of 1 mm have been observed raining out from large fires. Unlike hydrocarbon fuels, silane has the advantage that silica particles are the major combustion product resulting in a particle volume fraction a factor of ten greater than that for a carbonaceous smoke. There are two very desirable properties of silica aero-gels that are important for both space and earth based applications. The first important property is its inertness to most oxidizing and reducing atmospheres. Therefore, silica aero-gels make excellent fire ablatives and can be used in very demanding applications. The second important property is that silica aero-gels are expected to have very high porosity (greater than 0.999), making them lightweight and ideal for aerospace applications. The added benefit of the high porosity is that they can be used as extremely efficient filters for many earth based applications as well. Evidence of the formation of superagglomerates in a laminar acetylene/air diffusion flame was found by Sorensen et al. [1]. An interconnecting web of super-agglomerates was observed to span the width of the soot plume in the region just above the flame tip and described as a gel state. It was observed that this gel state immediately breaks up into agglomerates as larges as 100 m due to buoyancy induced turbulence. Large soot agglomerates were

  2. Ethylene Glycol Adsorption and Reaction over CeOX(111) Thin Films

    SciTech Connect

    T Chen; D Mullins

    2011-12-31

    This study reports the interaction of ethylene glycol with well-ordered CeO{sub x}(111) thin film surfaces. Ethylene glycol initially adsorbs on fully oxidized CeO{sub 2}(111) and reduced CeO{sub 2-x}(111) through the formation of one C-O-Ce bond and then forms a second alkoxy bond after annealing. On fully oxidized CeO{sub 2}(111) both recombination of ethylene glycol and water desorption occur at low temperature leaving stable -OCH{sub 2}CH{sub 2}O- (ethylenedioxy) intermediates and oxygen vacancies on the surface. This ethylenedioxy intermediate goes through C-C bond scission to produce formate species which then react to produce CO and CO{sub 2}. The formation of water results in the reduction of the ceria. On a reduced CeO{sub 2-x}(111) surface the reaction selectivity shifts toward a dehydration process. The ethylenedioxy intermediate decomposes by breaking a C-O bond and converts into an enolate species. Similar to the reaction of acetaldehyde on reduced CeO{sub 2-x}(111), the enolate reacts to produce acetaldehyde, acetylene, and ethylene. The loss of O from ethylene glycol leads to a small amount of oxidation of the reduced ceria.

  3. Ethylene Glycol Adsorption and Reaction over CeOX(111) Thin Films

    SciTech Connect

    Mullins, David R; Chen, Tsung-Liang

    2011-01-01

    This study reports the interaction of ethylene glycol with well-ordered CeO{sub x}(111) thin film surfaces. Ethylene glycol initially adsorbs on fully oxidized CeO{sub 2}(111) and reduced CeO{sub 2-x}(111) through the formation of one C-O-Ce bond and then forms a second alkoxy bond after annealing. On fully oxidized CeO{sub 2}(111) both recombination of ethylene glycol and water desorption occur at low temperature leaving stable -OCH{sub 2}CH{sub 2}O- (ethylenedioxy) intermediates and oxygen vacancies on the surface. This ethylenedioxy intermediate goes through C-C bond scission to produce formate species which then react to produce CO and CO{sub 2}. The formation of water results in the reduction of the ceria. On a reduced CeO{sub 2-x}(111) surface the reaction selectivity shifts toward a dehydration process. The ethylenedioxy intermediate decomposes by breaking a C-O bond and converts into an enolate species. Similar to the reaction of acetaldehyde on reduced CeO{sub 2-x}(111), the enolate reacts to produce acetaldehyde, acetylene, and ethylene. The loss of O from ethylene glycol leads to a small amount of oxidation of the reduced ceria.

  4. Anthropogenic and biogenic sources of Ethylene and the potential for human exposure: A literature review.

    PubMed

    Morgott, David A

    2015-11-05

    This review examines available published information on ethylene emission sources, emission magnitudes, and inhalation exposures in order to assess those factors and circumstances that can affect human contact with this omnipresent gas. The results reveal that airborne ethylene concentrations at the ppb levels are commonplace and can arise in the vicinity of traffic corridors, forest fires, indoor kitchens, horticultural areas, oil fields, house fires, and petrochemical sites. The primary biogenic sources of ethylene derive from microbial activity in most soil and marine environments as well as its biological formation in wide variety of plant species. Sizable amounts of ethylene can also result from the burning of fossil fuels, forest and savanna fires, and crop residue combustion. Motor vehicle exhaust is the largest contributor to urban ethylene levels under most circumstances, but industrial flare releases and fugitive emissions may also be of relevance. Occupational exposures generally range up to about 50-100 ppm and have been documented for those working in the horticultural, petrochemical, and fire and rescue industries. Continuous personal monitoring at the community level has documented exposures of 3-4 ppb. These levels are more closely associated with the ethylene concentrations found indoors rather than outdoors indicating the importance of exposure sources found within the home. Indoor air sources of ethylene are associated with environmental tobacco smoke, wood or propane fuel use, fruit and vegetable storage, and cooking. Ethylene is not found in any consumer or commercial products and does not off-gas from building products to any appreciable extent. The review indicates that outdoor sources located some distance from the home do not make an appreciable contribution to personal exposures given the strength and variety of sources found in the immediate living environment.

  5. Reactions of acetylenes in superbasic media. Recent advances

    NASA Astrophysics Data System (ADS)

    Trofimov, B. A.; Schmidt, E. Yu

    2014-07-01

    The main advances in the chemistry of acetylene in superbasic media achieved over the last five years are analyzed. Particular emphasis is placed on the ethynylation of aldehydes and ketones and C-, N- and O-vinylation. The cascade assembly of complex molecules in which ethynylation and vinylation are consecutive steps is considered. The bibliography includes 369 references.

  6. Acetylenic Coupling: A Powerful Tool in Molecular Construction.

    PubMed

    Siemsen; Livingston; Diederich

    2000-08-04

    Acetylenic coupling is currently experiencing some of the most intensive study of its long history. Rigid and sterically undemanding di- and oligoacetylene moieties, which are frequently encountered in natural products, are finding increasing application as key structural elements in synthetic receptors for molecular recognition. Interesting electronic and optical properties of extensively pi-conjugated systems have spurred research into new linear oligoalkynes and acetylenic carbon allotropes. The synthetic challenges associated with these efforts have in turn spawned new methods. While classical Glaser conditions are still frequently used for homocoupling, the demand for increasingly selective heterocoupling conditions has provided the focus of research over the past decades. These efforts have undoubtedly been hampered by a relatively poor mechanistic understanding of these processes. More recently, palladium-catalyzed coupling methods have led to improvements in both the selectivity and reliability of acetylenic homo- and heterocouplings and paved the way for their application to ever more complicated systems. The variety of acetylenic coupling protocols, the current mechanistic understanding, and their application in natural product and targeted synthesis are discussed comprehensively for the first time in this review, with an emphasis on the most recently developed methods, and their application to the synthesis of complex macromolecular structures.

  7. Acetylene soot reaction with NO in the presence of CO.

    PubMed

    Mendiara, T; Alzueta, M U; Millera, A; Bilbao, R

    2009-07-30

    The heterogeneous reaction of soot with NO can be considered as a means of reduction of the emissions of both pollutants from combustion systems. In this paper, the influence of the presence of CO in the soot-NO reaction is studied. Soot was obtained by pyrolysis at 1373 K of 5000 ppmv acetylene in nitrogen. The study of the influence of CO on the soot-NO reaction was performed in experiments fixing NO concentration at 900 ppmv and introducing different CO concentrations among 0 and 9900 ppmv. An increase in both the carbon consumption rate and NO reduction by acetylene soot was observed as the concentration of CO increases. These results can be explained by the oxide-stripping reaction, CO+C(f)(O)-->CO(2)+C(f). The direct reaction of CO with NO catalyzed by the carbon surface, CO+NO-->CO(2)+1/2N(2) may not be considered in this case the dominant process due to the absence of mineral impurities in the acetylene soot. The influence of CO in the acetylene soot-NO reaction was also tested in the presence of oxygen (250-5000 ppmv). In these conditions and for relatively high CO/O(2) ratios, CO seems to also contribute to NO reduction by the previous oxide-stripping reaction.

  8. Interstitial pneumonitis after acetylene welding: a case report.

    PubMed

    Brvar, Miran

    2014-01-01

    Acetylene is a colorless gas commonly used for welding. It acts mainly as a simple asphyxiant. In this paper, however, we present a patient who developed a severe interstitial pneumonitis after acetylene exposure during aluminum welding. A 44-year old man was welding with acetylene, argon and aluminum electrode sticks in a non-ventilated aluminum tank for 2 h. Four hours after welding dyspnea appeared and 22 h later he was admitted at the Emergency Department due to severe respiratory insufficiency with pO2 = 6.7 kPa. Chest X-ray showed diffuse interstitial infiltration. Pulmonary function and gas diffusion tests revealed a severe restriction (55% of predictive volume) and impaired diffusion capacity (47% of predicted capacity). Toxic interstitial pneumonitis was diagnosed and high-dose systemic corticosteroid methylprednisolone and inhalatory corticosteroid fluticasone therapy was started. Computed Tomography (CT) of the lungs showed a diffuse patchy ground-glass opacity with no signs of small airway disease associated with interstitial pneumonitis. Corticosteroid therapy was continued for the next 8 weeks gradually reducing the doses. The patient's follow-up did not show any deterioration of respiratory function. In conclusion, acetylene welding might result in severe toxic interstitial pneumonitis that improves after an early systemic and inhalatory corticosteroid therapy.

  9. Fatal carbon monoxide intoxication after acetylene gas welding of pipes.

    PubMed

    Antonsson, Ann-Beth; Christensson, Bengt; Berge, Johan; Sjögren, Bengt

    2013-06-01

    Acetylene gas welding of district heating pipes can result in exposure to high concentrations of carbon monoxide. A fatal case due to intoxication is described. Measurements of carbon monoxide revealed high levels when gas welding a pipe with closed ends. This fatality and these measurements highlight a new hazard, which must be promptly prevented.

  10. Nitrogen Fixation (Acetylene Reduction) Associated with Duckweed (Lemnaceae) Mats

    PubMed Central

    Zuberer, D. A.

    1982-01-01

    Duckweed (Lemnaceae) mats in Texas and Florida were investigated, using the acetylene reduction assay, to determine whether nitrogen fixation occurred in these floating aquatic macrophyte communities. N2-fixing microorganisms were enumerated by plating or most-probable-number techniques, using appropriate N-free media. Results of the investigations indicated that substantial N2-fixation (C2H2) was associated with duckweed mats in Texas and Florida. Acetylene reduction values ranged from 1 to 18 μmol of C2H4 g (dry weight)−1 day−1 for samples incubated aerobically in light. Dark N2 fixation was always two- to fivefold lower. 3-(3,4-Dichlorophenyl)-1,1-dimethylurea (7 to 10 μM) reduced acetylene reduction to levels intermediate between light and dark incubation. Acetylene reduction was generally greatest for samples incubated anaerobically in the light. It was estimated that 15 to 20% of the N requirement of the duckweed could be supplied through biological nitrogen fixation. N2-fixing heterotrophic bacteria (105 cells g [wet weight]−1 and cyanobacteria (105 propagules g [wet weight]−1 were associated with the duckweed mats. Azotobacter sp. was not detected in these investigations. One diazotrophic isolate was classified as Klebsiella. PMID:16345992

  11. Acetylene absorption and binding in nonporous crystal lattice

    SciTech Connect

    Thallapally, Praveen K.; Dobrzanska, Liliana B.; Gingrich, Todd R.; Wirsig, Trevor B.; Barbour, Leonard J.; Atwood, Jerry L.

    2006-09-01

    Unusual storage: An organic nonporous material, p-tert-butylcalix[4]arene, sorbs acetylene with high storage density under ambient conditions. It is presumed that gas molecules diffuse through the seemingly nonporous lattice without disrupting the arrangement of the host molecules (see picture; red O, blue C, gray H, yellow void space).

  12. Gas Phase UTE MRI of Propane and Propene

    PubMed Central

    Kovtunov, Kirill V.; Romanov, Alexey S.; Salnikov, Oleg G.; Barskiy, Danila A.; Chekmenev, Eduard Y.; Koptyug, Igor V.

    2016-01-01

    1H MRI of gases can potentially enable functional lung imaging to probe gas ventilation and other functions. In this work, 1H MR images of hyperpolarized and thermally polarized propane gas were obtained using UTE (ultrashort echo time) pulse sequence. A 2D image of thermally polarized propane gas with ~0.9×0.9 mm2 spatial resolution was obtained in less than 2 seconds, demonstrating that even non-hyperpolarized hydrocarbon gases can be successfully utilized for conventional proton MRI. The experiments were also performed with hyperpolarized propane gas and demonstrated acquisition of high-resolution multi-slice FLASH 2D images in ca. 510 s and non slice-selective 2D UTE MRI images in ca. 2 s. The UTE approach adopted in this study can be potentially used for medical lung imaging. Furthermore, the possibility to combine UTE with selective suppression of 1H signals from one of the two gases in a mixture is demonstrated in this MRI study. The latter can be useful for visualizing industrially important processes where several gases may be present, e.g., gas-solid catalytic reactions. PMID:27478870

  13. Differential microbial transformation of nitrosamines by an inducible propane monooxygenase.

    PubMed

    Homme, Carissa L; Sharp, Jonathan O

    2013-07-02

    The toxicity of N-nitrosamines, their presence in drinking and environmental water supplies, and poorly understood recalcitrance collectively necessitate a better understanding of their potential for bioattenuation. Here, we show that the bacterial strain Rhodococcus jostii RHA1 can biotransform N-nitrosodiethylamine (NDEA), N-nitrosodi-n-propylamine (NDPA), N-nitrosopyrrolidine (NPYR), and possibly N-nitrosomorpholine (NMOR) in addition to N-nitrosodimethylamine (NDMA). Growth of cells on propane as the sole carbon source greatly enhanced degradation rates when contrasted with cells grown on complex organics. Propane-induced rates in order of fastest to slowest were NDMA > NDEA > NDPA > NPYR > NMOR at concentrations <2000 μg/L. Removal rates for linear functional groups scaled inversely with mass and cyclic nitrosamines were more recalcitrant than linear nitrosamines. Controls demonstrated significant NDEA and NDPA losses independent of biomass, suggesting abiotic processes may play a role in attenuation of these two compounds under experimental conditions tested here. In contrast to NDMA, a transition from first to zero order kinetics was not observed for the other nitrosamines included in this study over a concentration range of 20-2000 μg/L. A genetic knockout for the propane monooxygenase enzyme (PrMO) confirmed the role of this enzyme in the biotransformation of NDEA and NPYR. This study furthers our understanding of environmental nitrosamine attenuation by revealing an enzymatic mechanism for the biotransformation of multiple nitrosamines, their relative recalcitrance to transformation, and potential for abiotic loss.

  14. Lipase-catalyzed hydrolysis of TG containing acetylenic FA.

    PubMed

    Jie, Marcel S F Lie Ken; Fua, Xun; Lau, Maureen M L; Chye, M L

    2002-10-01

    Hydrolysis of symmetrical acetylenic TG of type AAA [viz., glycerol tri-(4-decynoate), glycerol tri-(6-octadecynoate), glycerol tri-(9-octadecynoate), glycerol tri-(10-undecynoate), and glycerol tri-(13-docosynoate)] in the presence of eight microbial lipases was studied. Novozyme 435 (Candida antarctica), an efficient enzyme for esterification, showed a significant resistance in the hydrolysis of glycerol tri-(9-octadecynoate) and glycerol tri-(13-docosynoate). Hydrolysis of acetylenic TG with Lipolase 100T (Humicola lanuginosa) was rapidly accomplished. Lipase PS-D (Pseudomonas cepacia) showed a fair resistance toward the hydrolysis of glycerol tri-(6-octadecynoate) only, which reflected its ability to recognize the delta6 positional isomer of 18:1. Lipase CCL (Candida cylindracea, syn. C. rugosa) and AY-30 (C. rugosa) were able to catalyze the release of 10-undecynoic acid and 9-octadecynoic acid from the corresponding TG, but less readily the 13-docosynoic acid in the case of glycerol tri-(13-docosynoate). The two lipases CCL and AY-30 were able to distinguish the small difference in structure of fatty acyl moieties in the TG substrate. To confirm this trend, three regioisomers of mixed acetylenic TG of type ABC (containing one each of delta6, delta9, and delta13 acetylenic FA in various positions) were prepared and hydrolyzed with CCL and AY-40. The results reconfirmed the observation that AY-30 and CCL were able to distinguish the slight differences in the molecular structure (position of the acetylenic bond and chain length) of the acyl groups in the TG during the hydrolysis of such TG substrates.

  15. Towards Structural-Functional Mimics of Acetylene Hydratase: Reversible Activation of Acetylene using a Biomimetic Tungsten Complex.

    PubMed

    Peschel, Lydia M; Belaj, Ferdinand; Mösch-Zanetti, Nadia C

    2015-10-26

    The synthesis and characterization of a biomimetic system that can reversibly bind acetylene (ethyne) is reported. The system has been designed to mimic catalytic intermediates of the tungstoenzyme acetylene hydratase. The thiophenyloxazoline ligand S-Phoz (2-(4',4'-dimethyloxazolin-2'-yl)thiophenolate) is used to generate a bioinspired donor environment around the W center, facilitating the stabilization of W-acetylene adducts. The featured complexes [W(C2 H2 )(CO)(S-Phoz)2 ] (2) and [WO(C2 H2 )(S-Phoz)2 ] (3) are extremely rare from a synthetic and structural point of view as very little is known about W-C2 H2 adducts. Upon exposure to visible light, 3 can release C2 H2 from its coordination sphere to yield the 14-electron species [WO(S-Phoz)2 ] (4). Under light-exclusion 4 re-activates C2 H2 making this the first fully characterized system for the reversible activation of acetylene.

  16. Experimental study on transmission of an overdriven detonation wave from propane/oxygen to propane/air

    SciTech Connect

    Li, J.; Lai, W.H.; Chung, K.; Lu, F.K.

    2008-08-15

    Two sets of experiments were performed to achieve a strong overdriven state in a weaker mixture by propagating an overdriven detonation wave via a deflagration-to-detonation transition (DDT) process. First, preliminary experiments with a propane/oxygen mixture were used to evaluate the attenuation of the overdriven detonation wave in the DDT process. Next, experiments were performed wherein a propane/oxygen mixture was separated from a propane/air mixture by a thin diaphragm to observe the transmission of an overdriven detonation wave. Based on the characteristic relations, a simple wave intersection model was used to calculate the state of the transmitted detonation wave. The results showed that a rarefaction effect must be included to ensure that there is no overestimate of the post-transmission wave properties when the incident detonation wave is overdriven. The strength of the incident overdriven detonation wave plays an important role in the wave transmission process. The experimental results showed that a transmitted overdriven detonation wave occurs instantaneously with a strong incident overdriven detonation wave. The near-CJ state of the incident wave leads to a transmitted shock wave, and then the transition to the overdriven detonation wave occurs downstream. The attenuation process for the overdriven detonation wave decaying to a near-CJ state occurs in all tests. After the attenuation process, an unstable detonation wave was observed in most tests. This may be attributed to the increase in the cell width in the attenuation process that exceeds the detonability cell width limit. (author)

  17. Synthese de noir de carbone a partir de propane, utilisant un plasma thermique

    NASA Astrophysics Data System (ADS)

    Lavoie, Martin

    Ce projet de maitrise consiste principalement en une etude experimentale de la production de noir de carbone a haute valeur a partir des fractions lourdes du gaz naturel et a l'aide d'une plasma genere par induction electromagnetique. Cette etude comprend les aspects thermodynamiques de la decomposition des hydrocarbures comme le propane et le n-butane, la filtration en continu du noir de carbone et sa caracterisation. L'etude experimentale est realisee en deux phases distinctes: une phase exploratoire et une phase de mise a l'echelle. A l'issue de la phase exploratoire, un parametre se demarque des autres, le mode d'injection du gaz de procede. En effet, la morphologie du noir de carbone est completement differente selon le type d'injection choisi. Une injection radiale donne un noir de carbone en forme de plaquettes ayant une surface specifique elevee alors qu'une injection axiale donne un noir de carbone en forme de spheres ayant une surface specifique plus faible. Le design du systeme pour la phase de mise a l'echelle a tenu compte majoritairement du parametre qu'est l'injection. De plus, la deuxieme phase a permis une instrumentation adequate, une augmentation de la puissance et du debit du gaz de procede et une frequence differente (3 MHz a 400 kHz). Les resultats de la deuxieme phase se sont averes differents du point de vue morphologique. Plusieurs types d'injection ont ete testes et le noir de carbone obtenu contenait tres peu de plaquettes. L'injection joue un role important pour le taux de decomposition et du noir de carbone produit. Un debit de noir de carbone allant jusqu'a 21 grammes par minute a ete obtenu pour une injection radiale. En fait, les injections radiales testees etaient concues pour perturber l'ecoulement laminaire du plasma et ainsi obtenir de meilleurs echanges que l'injection axiale. Par contre, a faible debit, l'injection axiale est favorisee. Certains aspects demeurent encore a etudier et a approfondir. D'abord, l'effet de la

  18. Kinetic modeling of propane aromatization reaction over HZSM-5 and GaHZSM-5

    SciTech Connect

    Lukyanov, D.B.; Gnep, N.S.; Guisnet, M.R. . Catalyse en Chimie Organique)

    1995-02-01

    A detailed kinetic model for a propane aromatization reaction over HZSM-5 and GaHZSM-5 is developed. Kinetic modeling results show that propane transformation over HZSM-5 occurs via protolytic cracking and hydrogen transfer routes. The contributions of both routes in propane conversion are established. Rate constants of propane transformation steps are found to be at least 1,000 times lower than the rate constants of diene formation steps, which, in turn, are the slowest among the acid-catalyzed olefin aromatization steps. Gallium introduced into ZSM-5 catalyst is active in dehydrogenation of propane into propene, of olefins into dienes, and of naphthenes into aromatics. At the same time, gallium species catalyze propane transformation into methane and ethene hydrogenation into ethane. Both latter reactions appear to be the main reasons for the limit to aromatics selectivity over GaHZSM-5 catalysts.

  19. Ethylene in mutualistic symbioses

    PubMed Central

    Khatabi, Behnam; Schäfer, Patrick

    2012-01-01

    Ethylene (ET) is a gaseous phytohormone that participates in various plant physiological processes and essentially contributes to plant immunity. ET conducts its functions by regulating the expression of ET-responsive genes or in crosstalk with other hormones. Several recent studies have shown the significance of ET in the establishment and development of plant-microbe interactions. Therefore, it is not surprising that pathogens and mutualistic symbionts target ET synthesis or signaling to colonize plants. This review introduces the significance of ET metabolism in plant-microbe interactions, with an emphasis on its role in mutualistic symbioses. PMID:23072986

  20. Interstellar Antifreeze: Ethylene Glycol

    NASA Technical Reports Server (NTRS)

    Hollis, J. M.; Lovas, F. J.; Jewell, P. R.; Coudert, L. H.

    2002-01-01

    Interstellar ethylene glycol (HOCH2CH2,OH) has been detected in emission toward the Galactic center source Sagittarius B2(N-LMH) by means of several millimeter-wave rotational torsional transitions of its lowest energy conformer. The types and kinds of molecules found to date in interstellar clouds suggest a chemistry that favors aldehydes and their corresponding reduced alcohols-e.g., formaldehyde (H2CO)/methanol (CH3OH), acetaldehyde (CH3CHO)/ethanol (CH3CH2OH). Similarly, ethylene glycol is the reduced alcohol of glycolaldehyde (CH2OHCHO), which has also been detected toward Sgr B2(N-LMH). While there is no consensus as to how any such large complex molecules are formed in the interstellar clouds, atomic hydrogen (H) and carbon monoxide (CO) could form formaldehyde on grain surfaces, but such surface chemistry beyond that point is uncertain. However, laboratory experiments have shown that the gas-phase reaction of atomic hydrogen (H) and solid-phase CO at 10-20 K can produce formaldehyde and methanol and that alcohols and other complex molecules can be synthesized from cometary ice analogs when subject to ionizing radiation at 15 K. Thus, the presence of aldehyde/ reduced alcohol pairs in interstellar clouds implies that such molecules are a product of a low-temperature chemistry on grain surfaces or in grain ice mantles. This work suggests that aldehydes and their corresponding reduced alcohols provide unique observational constraints on the formation of complex interstellar molecules.

  1. Actuator based on sulfonated comb copolymer of poly (ethylene-co-vinyl alcohol) grafted by poly (ethylene glycol)

    NASA Astrophysics Data System (ADS)

    Gong, Guifen; Li, Lei; Zhang, Yujun

    2007-07-01

    Comb copolymer consisting of poly (ethylene-co-vinyl alcohol) (EVAL) as backbone and poly (ethylene glycol) (PEG) as side chains (EVAL-g-PEG) has been synthesized, then it was sulfonated by 1,3-propane sultone to get the final ionomer (EVAL-g-SPEG), and ionic polymer-metal composite (IPMC) based on EVAL-g-SPEG was prepared through electroless deposition of platinum onto the surfaces of EVAL-g-SPEG membrane. The graft copolymers were characterized with respect to molecular weight using gel permeation chromatography (GPC) and composition using 1H-NMR. The results showed that the No. of PEG graft of the side chains is n=1, 2 and others. Thermal properties were examined by DSC and TG. The melt temperature (T m) and glass transition temperature (T g) of the comb copolymer increase with the increasing length and the number of the side chains. Moreover, the deformation performance of IPMC material was tested and its results show that the starting response voltage of IPMC actuator decreases with the increasing IEC value. On the other hand, the starting response voltage increases with the decreased side chain length. The IPMC with n=2 side chain length of PEG has the maximum tip displacement, and the maximum tip displacement of IPMC membrane generally decreases with the side chain length of EVAL-g-SPEG. This feature may be the reflection of two opposite effects, namely the decreasing ion densities and increasing water sorption of the membrane.

  2. Computational modeling of a direct propane fuel cell

    NASA Astrophysics Data System (ADS)

    Khakdaman, H.; Bourgault, Y.; Ternan, M.

    2011-03-01

    The first two dimensional mathematical model of a complete direct propane fuel cell (DPFC) is described. The governing equations were solved using FreeFem software that uses finite element methods. Robin boundary conditions were used to couple the anode, membrane, and cathode sub-domains successfully. The model showed that a polytetrafluoroethylene membrane having its pores filled with zirconium phosphate (ZrP-PTFE), in a DPFC at 150 °C performed much the same as other electrolytes; Nafion, aqueous H3PO4, and H2SO4 doped polybenzimidazole, when they were used in DPFCs. One advantage of a ZrP-PTFE at 150 °C is that it operates without liquid phase water. As a result corrosion will be much less severe and it may be possible for non-precious metal catalysts to be used. Computational results showed that the thickness of the catalyst layer could be increased sufficiently so that the pressure drop between the reactant and product channels of the interdigitated flow fields is small. By increasing the width of the land and therefore the reactant's contact time with the catalyst it was possible to approach 100% propane conversion. Therefore fuel cell operation with a minimum concentration of propane in the product stream should be possible. Finally computations of the electrical potential in the ZrP phase, the electron flux in the Pt/C phase, and the overpotential in both the anode and cathode catalyst layers showed that serious errors in the model occurred because proton diffusion, caused by the proton concentration gradient, was neglected in the equation for the conservation of protons.

  3. Communication: Observation of local-bender eigenstates in acetylene.

    PubMed

    Steeves, Adam H; Park, G Barratt; Bechtel, Hans A; Baraban, Joshua H; Field, Robert W

    2015-08-21

    We report the observation of eigenstates that embody large-amplitude, local-bending vibrational motion in acetylene by stimulated emission pumping spectroscopy via vibrational levels of the S1 state involving excitation in the non-totally symmetric bending modes. The N(b) = 14 level, lying at 8971.69 cm(-1) (J = 0), is assigned on the basis of degeneracy due to dynamical symmetry breaking in the local-mode limit. The level pattern for the N(b) = 16 level, lying at 10 218.9 cm(-1), is consistent with expectations for increased separation of ℓ = 0 and 2 vibrational angular momentum components. Increasingly poor agreement between our observations and the predicted positions of these levels highlights the failure of currently available normal mode effective Hamiltonian models to extrapolate to regions of the potential energy surface involving large-amplitude displacement along the acetylene ⇌ vinylidene isomerization coordinate.

  4. Enhanced Photoluminescence in Acetylene-Treated ZnO Nanorods.

    PubMed

    Jäppinen, Luke; Jalkanen, Tero; Sieber, Brigitte; Addad, Ahmed; Heinonen, Markku; Kukk, Edwin; Radevici, Ivan; Paturi, Petriina; Peurla, Markus; Shahbazi, Mohammad-Ali; Santos, Hélder A; Boukherroub, Rabah; Santos, Hellen; Lastusaari, Mika; Salonen, Jarno

    2016-12-01

    Zinc oxide (ZnO) nanorods were manufactured using the aqueous chemical growth (ACG) method, and the effect of thermal acetylene treatment on their morphology, chemical composition, and optical properties was investigated. Changes in the elemental content of the treated rods were found to be different than in previous reports, possibly due to the different defect concentrations in the samples, highlighting the importance of synthesis method selection for the process. Acetylene treatment resulted in a significant improvement of the ultraviolet photoluminescence of the rods. The greatest increase in emission intensity was recorded on ZnO rods treated at the temperature of 825 °C. The findings imply that the changes brought on by the treatment are limited to the surface of the ZnO rods.

  5. Enhanced acetylene emission near the north pole of Jupiter

    NASA Technical Reports Server (NTRS)

    Drossart, Pierre; Bezard, Bruno; Encrenaz, Therese; Atreya, Sushil; Lacy, John; Serabyn, Eugene; Tokunaga, Alan

    1986-01-01

    The present paper is concerned with observations of acetylene fundamental and hot band vibrational emission lines from the planet Jupiter. It is pointed out that the observation of a polar bright spot in the atmosphere of Jupiter is characterized by an enhancement in the individual lines of C2H2 which can be interpreted as an enhancement in the acetylene abundance. However, a purely thermal effect, on non-LTE phenomena cannot be excluded. The intensity of the observed hot band lines is also consistent with either hypothesis. The reported observations were performed with a cooled Fabry-Perot Grating Spectrometer (FPGS). Observations and instrumentation are considered in detail along with the calculation of synthetic spectra on the basis of a line-by-line computation, and the interpretation of the obtained data.

  6. Enhanced acetylene emission near the north pole of Jupiter

    NASA Technical Reports Server (NTRS)

    Drossart, P.; Bezard, B.; Atreya, S.; Lacy, J.; Serabyn, E.

    1986-01-01

    The present paper is concerned with observations of acetylene fundamental and hot band vibrational emission lines from the planet Jupiter. It is pointed out that the observation of a polar bright spot in the atmosphere of Jupiter is characterized by an enhancement in the individual lines of C2H2 which can be interpreted as an enhancement in the acetylene abundance. However, a purely thermal effect, or non-LTE phenomena cannot be excluded. The intensity of the observed hot band lines is also consistent with either hypothesis. The reported observations were performed with a cooled Fabry-Perot Grating Spectrometer (FPGS). Observations and instrumentation are considered in detail along with the calculation of synthetic spectra on the basis of a line-by-line computation, and the interpretation of the obtained data.

  7. Supercritical convection, critical heat flux, and coking characteristics of propane

    NASA Technical Reports Server (NTRS)

    Rousar, D. C.; Gross, R. S.; Boyd, W. C.

    1984-01-01

    The heat transfer characteristics of propane at subcritical and supercritical pressure were experimentally evaluated using electrically heated Monel K-500 tubes. A design correlation for supercritical heat transfer coefficient was established using the approach previously applied to supercritical oxygen. Flow oscillations were observed and the onset of these oscillations at supercritical pressures was correlated with wall-to-bulk temperature ratio and velocity. The critical heat flux measured at subcritical pressure was correlated with the product of velocity and subcooling. Long duration tests at fixed heat flux conditions were conducted to evaluate coking on the coolant side tube wall and coking rates comparable to RP-1 were observed.

  8. Thermodynamic study on the formation of acetylene during coal pyrolysis in the arc plasma jet

    SciTech Connect

    Bao, W.; Li, F.; Cai, G.; Lu, Y.; Chang, L.

    2009-07-01

    Based on the principle of minimizing the Gibbs free energy, the composition of C-H-O-N-S equilibrium system about acetylene formation during the pyrolysis in arc plasma jet for four kinds of different rank-ordered coals such as Datong, Xianfeng, Yangcheng, and Luan was analyzed and calculated. The results indicated that hydrogen, as the reactive atmosphere, was beneficial to the acetylene formation. The coal ranks and the hydrogen, oxygen, nitrogen, and sulfur in coal all could obviously affect the acetylene yield. The mole fraction of acetylene is the maximum when the ratio value of atom H/C was 2. The content of oxygen was related to the acetylene yield, but it does not compete with CO formation. These agreed with the experimental results, and they could help to select the coal type for the production of acetylene through plasma pyrolysis process.

  9. Acetylene bubble-powered autonomous capsules: towards in situ fuel.

    PubMed

    Moo, James Guo Sheng; Wang, Hong; Pumera, Martin

    2014-12-28

    A fuel-free autonomous self-propelled motor is illustrated. The motor is powered by the chemistry of calcium carbide and utilising water as a co-reactant, through a polymer encapsulation strategy. Expulsion of acetylene bubbles powers the capsule motor. This is an important step, going beyond the toxic hydrogen peroxide fuel used normally, to find alternative propellants for self-propelled machines.

  10. High-Resolution Tunable Diode Laser Spectroscopy of Methane

    DTIC Science & Technology

    1986-03-01

    quantitative data from test 14. This table shows that ethylene is by far the most abundant species, with propane and acetylene also being major species. The...Test 14 1. Ethane 2.21 2. Ethylene 77.80 3. Propane 0.75 4. Acetylene 18.61 5. Propene 26.52 6. Acetaldehyde 1.83 7. 1-Butene 5.83 8. 1,3...21. Benzene 9.07 22. l-Heptene 3.16 23. N-Heptane 0.44 24. Toluene 3.33 25. Hexanal 1.09 26. 1- Octene 2.13 27. N-Octane 0.63 28. Ethylbenzene

  11. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 2. Green rust.

    PubMed

    Lee, Woojin; Batchelor, Bill

    2002-12-15

    Abiotic reductive dechlorination of chlorinated ethylenes by the sulfate form of green rust (GR(SO4)) was examined in batch reactors. Dechlorination kinetics were described by a modified Langmuir-Hinshelwood model. The rate constant for reductive dechlorination of chlorinated ethylenes at reactive GR(SO4) surfaces was in the range of 0.592 (+/-4.4%) to 1.59 (+/-6.3%) day(-1). The specific reductive capacity of GR(SO4) for target organics was in the range of 9.86 (+/-10.1%) to 18.0 (+/-4.3%) microM/g and sorption coefficient was in the range of 0.53 (+/-2.4%) to 1.22 (+/-4.3%) mM(-1). Surface area-normalized pseudo-first-order initial rate constants for chlorinated ethylenes by GR(SO4) were 3.4 to 8.2 times greater than those by pyrite. Chlorinated ethylenes were mainly transformed to acetylene, and no detectable amounts of chlorinated intermediates were observed. The rate constants for the reductive dechlorination of trichloroethylene (TCE) increased as pH increased (6.8 to 10.1) but were independent of solid concentration and initial TCE concentration. Magnetite and/or maghemite were produced by the oxidation of GR(SO4) by TCE. These findings are relevant to the understanding of the role of abiotic reductive dechlorination during natural attenuation in environments that contain GR(SO4).

  12. Microwave Enhanced Direct Cracking of Hydrocarbon Feedstock for Energy Efficient Production of Ethylene and Propylene.

    SciTech Connect

    Shulman, Holly; Fall, Morgana; Wagner, Eric; Bowlin, Ricardo

    2012-02-13

    This project demonstrated microwave cracking of ethane with good product conversion and ethylene selectivity, with a short residence time ({approx}0.001 sec). The laboratory scale equipment was designed and built, along with concept designs for larger scale implementation. The system was operated below atmospheric pressures, in the range of 15-55 torr, with argon as a carrier gas. The measured products included hydrogen, methane, acetylene, and ethylene. The results followed similar trends to those predicted by the modeling software SPYRO{reg_sign}, with the exception that the microwave appeared to produce slightly lower amounts of ethylene and methane, although enhanced analytical analysis should reduce the difference. Continued testing will be required to verify these results and quantify the energy consumption of microwave vs. conventional. The microwave cracking process is an attractive option due to the possibility of selectively heating the reaction volume rather than the reactor walls, which may allow novel reactor designs that result in more efficient production of ethylene. Supplemental studies are needed to continue the laboratory testing and refine processing parameters.

  13. Modeling encapsulation of acetylene molecules into carbon nanotubes.

    PubMed

    Tran-Duc, Thien; Thamwattana, Ngamta

    2011-06-08

    Polyacetylene is a well-known conductive polymer and when doped its conductivity can be altered by up to 12 orders of magnitude. However, due to entropy effects a polyacetylene chain usually suffers from distortions and interchain couplings which lead to unpredictable changes in its conducting property. Encapsulating a polyacetylene chain into a carbon nanotube can resolve these issues. Furthermore, since the carbon nanotube itself possesses excellent electrical conductivity, the combination of the carbon nanotube and polyacetylene may give rise to a new material with superior transport behavior. In this paper, we model mathematically the molecular interaction between an acetylene molecule and a carbon nanotube in order to determine conditions at which configurations of the acetylene molecule are accepted into the carbon nanotube as well as its equilibrium configurations inside various sizes of carbon nanotubes. For special cases of the acetylene molecule lying on the tube axis, standing vertically with its center on the tube axis and staying far inside the tube, explicit analytical expressions for the interaction energy are obtained.

  14. Quantifying Momentum Transfer Due to Blast Waves from Oxy-Acetylene Driven Shock Tubes

    DTIC Science & Technology

    2012-05-30

    Transfer Due to Blast Waves from Oxy - Acetylene Driven Shock Tubes 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d...and the response of materiel to blast loading. Recently, laboratory-scale shock tubes driven by oxy - acetylene were described. It was estimated that...later. In each case, most of the momentum transfer was due to the shock wave itself. The results support previous estimates that the oxy - acetylene

  15. Acetylene as a substrate in the development of primordial bacterial communities

    NASA Astrophysics Data System (ADS)

    Culbertson, Charles W.; Strohmaier, Francis E.; Oremland, Ronald S.

    1988-12-01

    The fermentation of atmospheric acetylene by anaerobic bacteria is proposed as the basis of a primordial heterotrophic food chain. The accumulation of fermentation products (acetaldehyde, ethanol, acetate and hydrogen) would create niches for sulfate-respiring bacteria as well as methanogens. Formation of acetylene-free environments in soils and sediments would also alter the function of nitrogenase from detoxification to nitrogen-fixation. The possibility of an acetylene-based anaerobic food chain in Jovian-type atmospheres is discussed.

  16. Thermodynamical Study on Production of Acetylene from Coal Pyrolysis in Hydrogen Plasma

    NASA Astrophysics Data System (ADS)

    Wang, Fei; Guo, Wenkang; Yuan, Xingqiu; Zhao, Taize

    2006-05-01

    The chemical thermodynamic equilibrium of acetylene production by coal pyrolysis in hydrogen plasma was studied. The thermodynamic equilibrium is obtained by using the method of free energy. Calculated results show that the hydrogen concentration in the equilibrium system is very important for the acetylene production by coal conversion and the energy consumption for the production of acetylene per-kilogram strongly depends on the hydrogen concentration and the temperature.

  17. Initial stages of soot formation in thermal pyrolysis of acetylene. I. Mechanism for homogeneous pyrolysis of acetylene

    SciTech Connect

    Merkulov, A.A.; Ovsyannikov, A.A.; Polak, L.S.; Popov, V.T.; Pustilnikov, V.Yu. )

    1989-03-01

    A probable mechanism for the homogeneous pyrolysis of acetylene, using carbene reactions, is considered. Analysis of the energetics for the probable mechanism of the initiation reactions shows the rearrangement C{sub 2}H{sub 2} {yields}:CCH{sub 2} to be the most probable. Using the energetic barriers for simple carbene reactions and formation enthalpies for more complicated carbenes, the authors evaluated the activation energies for the reactions mechanism. The vibrational excitation of the products of carbene reactions is taken into account. Calculations of the acetylene conversion kinetics and yields of the main gas-phase pyrolysis products, based on the carbene molecular mechanism, show significantly better agreement with available experimental data as compared to those based on traditional radical mechanisms. The calculated time for the appearance of aromatic products is close to the measured induction times for the appearance of soot particles.

  18. Interaction of the mechanism-based inactivator acetylene with ammonia monooxygenase of Nitrosomonas europaea.

    PubMed

    Gilch, Stefan; Vogel, Manja; Lorenz, Matthias W; Meyer, Ortwin; Schmidt, Ingo

    2009-01-01

    The ammonia monooxygenase (AMO) of Nitrosomonas europaea is a metalloenzyme that catalyses the oxidation of ammonia to hydroxylamine. We have identified histidine 191 of AmoA as the binding site for the oxidized mechanism-based inactivator acetylene. Binding of acetylene changed the molecular mass of His-191 from 155.15 to 197.2 Da (+42.05), providing evidence that acetylene was oxidized to ketene (CH2CO; 42.04 Da) which binds specifically to His-191. It must be assumed that His-191 is part of the acetylene-activating site in AMO or at least directly neighbours this site.

  19. Kinetics and Structure of Superagglomerates Produced by Silane and Acetylene

    NASA Technical Reports Server (NTRS)

    Mulholland, G. W.; Hamins, A.; Sivathanu, Y.

    1999-01-01

    The evolution of smoke in a laminar diffusion flame involves several steps. The first step is particle inception/nucleation in the high-temperature fuel-rich region of the flame followed by surface growth and coagulation/coalescence of the small particles. As the primary spheres grow in size and lose hydrogen, the colliding particles no longer coalesce but retain their identity as a cluster of primary spheres, termed an agglomerate. Finally, in the upper portion of the flame, the particles enter an oxidizing environment which may lead to partial or complete burnout of the agglomerates. Currently there is no quantitative model for describing the growth of smoke agglomerates up to superagglomerates with an overall dimension of 10 microns and greater. Such particles are produced during the burning of acetylene and fuels containing benzene rings such as toluene and polystyrene. In the case of polystyrene, smoke agglomerates in excess of 1 mm have been observed "raining" out from large fires. Evidence of the formation of superagglomerates in a laminar acetylene/air diffusion flame has been recently reported. Acetylene was chosen as the fuel since the particulate loading in acetylene/air diffusion flames is very high. Photographs were obtained by Sorensen using a microsecond xenon lamp of the "stream" of soot just above the flame. For low flow rates of acetylene, only submicrometer soot clusters are produced and they give rise to the homogeneous appearance of the soot stream. When the flow rate is increased to 1.7 cu cm/s, soot clusters up to 10 microns are formed and they are responsible for the graininess and at a flow rate of 3.4 cu cm/s, a web of interconnected clusters as large as the width of the flame is seen. This interconnecting web of superagglomerates is described as a gel state by Sorensen et al (1998). This is the first observation of a gel for a gas phase system. It was observed that this gel state immediately breaks up into agglomerates due to buoyancy

  20. Documentation for propane fleet conversion cost-effectiveness model

    NASA Astrophysics Data System (ADS)

    Taylor, D.; Euritt, M.; Mahmassani, H.

    1992-10-01

    Increased emphasis on energy efficiency and air quality has resulted in a number of state and federal initiatives examining the use of alternative fuels for motor vehicles. Texas instituted an alternative fuels program for public fleet operations beginning in the 1991-92 fiscal year. Life-cycle cost/benefit models for evaluating the economic implications of the action have been developed at the University of Texas at Austin Center for Transportation Research for both compressed natural gas (CNG) and propane. The report documents the various input data, calculations, and assumptions of the Propane Net Present Value (NPV) model. A similar report (number 983-1) documents the same for the CNG model. Input data with constant values across different fleets and locations are discussed first and include basic parameters for on-board storage capacity, vehicle conversion costs, equipment salvage values, etc. Variable input data, reflecting a given fleet size, composition, and location, include the number and types of vehicles, fuel consumption, etc. The next section presents the formulas for the internal model calculations. The final section discusses the basic assumptions underlying the model.

  1. Monofunctional hyperbranched ethylene oligomers.

    PubMed

    Wiedemann, Thomas; Voit, Gregor; Tchernook, Alexandra; Roesle, Philipp; Göttker-Schnetmann, Inigo; Mecking, Stefan

    2014-02-05

    The neutral κ(2)N,O-salicylaldiminato Ni(II) complexes [κ(2)N,O-{(2,6-(3',5'-R2C6H3)2C6H3-N═C(H)-(3,5-I2-2-O-C6H2)}]NiCH3(pyridine)] (1a-pyr, R = Me; 1b-pyr, R = Et; 1c-pyr, R = iPr) convert ethylene to hyperbranched low-molecular-weight oligomers (Mn ca. 1000 g mol(-1)) with high productivities. While all three catalysts are capable of generating hyperbranched structures, branching densities decrease significantly with the nature of the remote substituent along Me > Et > iPr and oligomer molecular weights increase. Consequently, only 1a-pyr forms hyperbranched structures over a wide range of reaction conditions (ethylene pressure 5-30 atm and 20-70 °C). An in situ catalyst system achieves similar activities and identical highly branched oligomer microstructures, eliminating the bottleneck given by the preparation and isolation of Ni-Me catalyst precursor species. Selective introduction of one primary carboxylic acid ester functional group per highly branched oligoethylene molecule was achieved by isomerizing ethoxycarbonylation and alternatively cross metathesis with ethyl acrylate followed by hydrogenation. The latter approach results in complete functionalization and no essential loss of branched oligomer material and molecular weight, as the reacting double bonds are close to a chain end. Reduction yielded a monoalcohol-functionalized oligomer. Introduction of one reactive epoxide group per branched oligomer occurs completely and selectively under mild conditions. All reaction steps involved in oligomerization and monofunctionalization are efficient and readily scalable.

  2. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  3. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  4. 46 CFR 154.1725 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e)...

  5. Quantification and Removal of Some Contaminating Gases from Acetylene Used to Study Gas-Utilizing Enzymes and Microorganisms

    PubMed Central

    Hyman, Michael R.; Arp, Daniel J.

    1987-01-01

    Acetylene generated from various grades of calcium carbide and obtained from commercial- and purified-grade acetylene cylinders was shown to contain high concentrations of various contaminants. Dependent on the source of acetylene, these included, at maximal values, H2 (0.023%), O2 (0.779%), N2 (3.78%), PH3 (0.06%), CH4 (0.073%), and acetone (1 to 10%). The concentration of the contaminants in cylinder acetylene was highly dependent on the extent of cylinder discharge. Several conventional methods used to partially purify cylinder acetylene were compared. A small-scale method for extensively purifying acetylene is described. An effect of acetylene quality on acetylene reduction assays conducted with purified nitrogenase from Azotobacter vinelandii was demonstrated. PMID:16347278

  6. 49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 2 2014-10-01 2014-10-01 false Charging of cylinders with compressed gas in solution (acetylene). 173.303 Section 173.303 Transportation Other Regulations Relating to Transportation....303 Charging of cylinders with compressed gas in solution (acetylene). (a) Cylinder, filler...

  7. 49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 2 2013-10-01 2013-10-01 false Charging of cylinders with compressed gas in solution (acetylene). 173.303 Section 173.303 Transportation Other Regulations Relating to Transportation....303 Charging of cylinders with compressed gas in solution (acetylene). (a) Cylinder, filler...

  8. 49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 2 2011-10-01 2011-10-01 false Charging of cylinders with compressed gas in solution (acetylene). 173.303 Section 173.303 Transportation Other Regulations Relating to Transportation....303 Charging of cylinders with compressed gas in solution (acetylene). (a) Cylinder, filler...

  9. 49 CFR 173.303 - Charging of cylinders with compressed gas in solution (acetylene).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 2 2012-10-01 2012-10-01 false Charging of cylinders with compressed gas in solution (acetylene). 173.303 Section 173.303 Transportation Other Regulations Relating to Transportation....303 Charging of cylinders with compressed gas in solution (acetylene). (a) Cylinder, filler...

  10. Complete genome sequences of two acetylene-fermenting Pelobacter acetylenicus strains

    USGS Publications Warehouse

    Sutton, John M.; Baesman, Shaun; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.; Akob, Denise M.

    2017-01-01

    Acetylene fermentation is a rare metabolism that was serendipitously discovered during C2H2-block assays of N2O reductase. Here, we report the genome sequences of two type strains of acetylene-fermenting Pelobacter acetylenicus, the freshwater bacterium DSM 3246 and the estuarine bacterium DSM 3247.

  11. Complete Genome Sequence of the Acetylene-Fermenting Pelobacter sp. Strain SFB93

    PubMed Central

    Baesman, Shaun M.; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.

    2017-01-01

    ABSTRACT Acetylene fermentation is a rare metabolism that was previously reported as being unique to Pelobacter acetylenicus. Here, we report the genome sequence of Pelobacter sp. strain SFB93, an acetylene-fermenting bacterium isolated from sediments collected in San Francisco Bay, CA. PMID:28183760

  12. Complete Genome Sequences of Two Acetylene-Fermenting Pelobacter acetylenicus Strains

    PubMed Central

    Baesman, Shaun M.; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.

    2017-01-01

    ABSTRACT Acetylene fermentation is a rare metabolism that was serendipitously discovered during C2H2-block assays of N2O reductase. Here, we report the genome sequences of two type strains of acetylene-fermenting Pelobacter acetylenicus, the freshwater bacterium DSM 3246 and the estuarine bacterium DSM 3247. PMID:28183759

  13. 46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... suction line. (c) The piping system, including the cargo refrigeration system, for tanks to be loaded with methyl acetylene-propadiene mixture must be completely separate from piping and refrigeration systems for other tanks. If the piping system for the tanks to be loaded with methyl acetylene-propadiene mixture...

  14. 46 CFR 151.50-79 - Methyl acetylene-propadiene mixture.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... suction line. (c) The piping system, including the cargo refrigeration system, for tanks to be loaded with methyl acetylene-propadiene mixture must be completely separate from piping and refrigeration systems for other tanks. If the piping system for the tanks to be loaded with methyl acetylene-propadiene mixture...

  15. Acetylene Fermentation: Relevance to Primordial Biogeochemistry and the Search for Life in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.

    2014-02-01

    Acetylene supports the growth of some terrestrial anaerobes. The reaction is highly exothermic. The abundance of acetylene in the methane-rich planet(oid)s of the outer solar system could represent a means of nourishment for resident alien microbes.

  16. Complete genome sequence of the acetylene-fermenting Pelobacter sp. strain SFB93

    USGS Publications Warehouse

    Sutton, John M.; Baesman, Shaun; Fierst, Janna L.; Poret-Peterson, Amisha T.; Oremland, Ronald S.; Dunlap, Darren S.; Akob, Denise M.

    2017-01-01

    Acetylene fermentation is a rare metabolism that was previously reported as being unique to Pelobacter acetylenicus. Here, we report the genome sequence of Pelobacter sp. strain SFB93, an acetylene-fermenting bacterium isolated from sediments collected in San Francisco Bay, CA.

  17. Effects of acido-basic support properties on the catalytic hydrogenation of acetylene on gold nano-particles

    NASA Astrophysics Data System (ADS)

    Manda, Abdullah Ahmed

    Metallic gold nanoparticles supported on gamma-Al2O 3 and magnesia-alumina mixed oxide, with different magnesia content have been prepared by sol-gel method and characterized by different techniques (inductive coupled plasma-mass spectroscopy (ICP-MS), XRD, BET surface area analysis, transmission electron microscopy (TEM), CO2 and NH 3 temperature programmed desorption (TPD), H2 temperature programmed reduction (TPR) and FTIR of adsorbed CO2). Such systems were found to produce catalysts with controllable acidity, varying from catalyst possessing large density of acidic and low density of basic sites, others with acidic and basic sites of equal strength and density, and others with large basic and low acid sites densities, respectively. The catalytic assessment of the generated acidity was carried out using 2-propanol decomposition as a test reaction. The results obtained indicate that the presence of magnesia and reduced gold nanopartilces has imparted the catalysts, 1%Au/4%Mg-Al 2O3 and 1%Au/8%Mg-Al2O3, with significant base-catalytic properties. Acetylene hydrogenation and formation of coke deposits were investigated on a gold catalyst supported on gamma-Al2O3 and gold supported on alumina-magnisia mixed oxide with different gold content; 1%Au/gamma-Al 2O3, 1%Au/15%Mg-Al2O3, 2%Au/15%Mg-Al 2O3 and 4%Au/15%Mg-Al2O3. The effect of the H2/C2H2 ratio was studied over a range of values. The catalytic activity and selectivity towards ethylene and other products were investigated at different reaction temperatures. Acetylene hydrogenation was investigated in the presence and absence of ethylene in stream. It is investigated that the adsorption of the triple bond is preferred over the double bond and during selective catalytic (SCR) of C2H2 the two hydrocarbons do not compete for the same adsorption sites. The deactivation of catalysts was studied by temperature programmed oxidation (TPO). Higher content of coke over 1%Au/Al2O3 catalyst was investigated in contrast to

  18. Propane spectral resolution enhancement by the maximum entropy method

    NASA Technical Reports Server (NTRS)

    Bonavito, N. L.; Stewart, K. P.; Hurley, E. J.; Yeh, K. C.; Inguva, R.

    1990-01-01

    The Burg algorithm for maximum entropy power spectral density estimation is applied to a time series of data obtained from a Michelson interferometer and compared with a standard FFT estimate for resolution capability. The propane transmittance spectrum was estimated by use of the FFT with a 2 to the 18th data sample interferogram, giving a maximum unapodized resolution of 0.06/cm. This estimate was then interpolated by zero filling an additional 2 to the 18th points, and the final resolution was taken to be 0.06/cm. Comparison of the maximum entropy method (MEM) estimate with the FFT was made over a 45/cm region of the spectrum for several increasing record lengths of interferogram data beginning at 2 to the 10th. It is found that over this region the MEM estimate with 2 to the 16th data samples is in close agreement with the FFT estimate using 2 to the 18th samples.

  19. Exhaust gas measurements in a propane fueled swirl stabilized combustor

    NASA Technical Reports Server (NTRS)

    Aanad, M. S.

    1982-01-01

    Exhaust gas temperature, velocity, and composition are measured and combustor efficiencies are calculated in a lean premixed swirl stabilized laboratory combustor. The radial profiles of the data between the co- and the counter swirl cases show significant differences. Co-swirl cases show evidence of poor turbulent mixing across the combustor in comparison to the counter-swirl cases. NO sub x levels are low in the combustor but substantial amounts of CO are present. Combustion efficiencies are low and surprisingly constant with varying outer swirl in contradiction to previous results under a slightly different inner swirl condition. This difference in the efficiency trends is expected to be a result of the high sensitivity of the combustor to changes in the inner swirl. Combustor operation is found to be the same for propane and methane fuels. A mechanism is proposed to explain the combustor operation and a few important characteristics determining combustor efficiency are identified.

  20. Chemical kinetic reaction mechanism for the combustion of propane

    NASA Technical Reports Server (NTRS)

    Jachimowski, C. J.

    1984-01-01

    A detailed chemical kinetic reaction mechanism for the combustion of propane is presented and discussed. The mechanism consists of 27 chemical species and 83 elementary chemical reactions. Ignition and combustion data as determined in shock tube studies were used to evaluate the mechanism. Numerical simulation of the shock tube experiments showed that the kinetic behavior predicted by the mechanism for stoichiometric mixtures is in good agrement with the experimental results over the entire temperature range examined (1150-2600K). Sensitivity and theoretical studies carried out using the mechanism revealed that hydrocarbon reactions which are involved in the formation of the HO2 radical and the H2O2 molecule are very important in the mechanism and that the observed nonlinear behavior of ignition delay time with decreasing temperature can be interpreted in terms of the increased importance of the HO2 and H2O2 reactions at the lower temperatures.

  1. [1,3-Bis(diphenylphosphino)propane]trichlorooxorhenium(V).

    PubMed

    Suescun, L; Mombrú, A W; Mariezcurrena, R A; Pardo, H; Russi, S; Kremer, C; Rivero, M; Kremer, E

    2000-08-01

    Trichlorooxo[1,3-propanediylbis(diphenylphosphine)-P,P ']rhenium(V), [ReCl(3)O(C(27)H(26)P(2))], crystallizes with four formula units per unit cell. The crystal structure consists of neutral complexes of [ReOCl(3)(dppp)] [dppp is 1,3-bis(diphenylphosphino)propane] packed by H.pi-ring interactions. The Re atom is octahedrally coordinated to the oxo anion, three Cl atoms and two P atoms from the dppp ligand. The six-membered ring formed by the bidentate dppp ligand and the rhenium metal centre is in a chair conformation. The title compound is an intermediate in the synthesis of bis(dppp) complexes of rhenium.

  2. Propane-1,3-diammonium dichromate(VI).

    PubMed

    Trabelsi, Sonia; Marouani, Houda; Al-Deyab, Salem S; Rzaigui, Mohamed

    2012-08-01

    The title compound, (C(3)H(12)N(2))[Cr(2)O(7)], consists of a discrete dichromate anion with an eclipsed conformation and a propane-1,3-diammonium cation. Both kinds of ions have a mirror plane passing through the bridging O atom and the central methyl-ene C atom of the Cr(2)O(7) (2-) and C(3)H(12)N(2) (2+) moieties, respectively. Anions and cations are alternately stacked to form columns parallel to the b axis. Ions are linked by intra- and inter-column hydrogen bonds of types N-H⋯O and C-H⋯O, involving O atoms of the dichromate anions as acceptors, and ammonium or methyl-ene groups as donors.

  3. An infrared study of the bending region of acetylene

    NASA Astrophysics Data System (ADS)

    Hillman, J. J.; Jennings, D. E.; Halsey, G. W.; Nadler, Shachar; Blass, W. E.

    1991-04-01

    Acetylene spectra observed with instrumental resolutions of 0.0025 and 0.005 cm-1 were obtained at The National Optical Astronomy Observatory, Tucson, Arizona using the FTS spectrometer at the National Solar Observatory McMath telescope facility. These resolutions are factors of 6 and 3 times, respectively, that of the best prior study in the literature. The higher resolution allowed the assignment of many more low-J Q-branch transitions. The range of optical densities available in this study also allowed the extension of observed and assigned transitions to significantly higher J-values than reported in prior studies. Availability of improved standard lines resulted in high quality transition wavenumbers which are accurate to approximately +/-0.0001 cm-1. Using proven combination difference techniques and analysis software, this study produces the best available molecular parameters for the ν4 and ν5 states of acetylene. In addition, because acetylene has no permanent dipole moment, this study extends the precision of available ground state parameters B0 and D0 and produces for the first time an estimator of H0. In addition to H0 values for both isotopic species treated, we have obtained for the first time a value for H5 for the dominant isotopmer. The value of H5 for the 13C12CH2 was not determined and thus thought to be significantly smaller than H5 for 12C2H2. This study also obtains l-doubling parameters for both degenerate fundamental states in the lesser isotopmer for the first time as well as H4 for both isotopmers and B4 and D4 for the lesser isotopmer. NASA/ASEE Summer Faculty Fellow, NASA/Goddard Space Flight Center, 1986, 1987 (during which periods a portion of this work was completed).

  4. Participation of ethylene in gravitropism

    NASA Technical Reports Server (NTRS)

    Harrison, M.; Pickard, B. G.

    1984-01-01

    In shoots of many plants, of which tomato (Lycopersicon esculentum Mill.) is an example, ethylene production is substantially increased during gravitropism. As a first step toward elucidating the role of ethylene in gravitropism, detailed time courses of ethylene production in isolated hypocotyl segments and whole plants were measured for gravistimulated and upright tomato seedlings. In the first experiment, seedlings were set upright or laid horizontal and then, at 15 min intervals, sets of hypocotyls were excised and sealed into gas tight vials. A steady long term rise in ethylene production begins after 15 min gravistimulation. It is possible that this increase is a consequence of the accumulation of indoleacetic acid (IAA) in the lower tissue of the hypocotyle. In a second kind of experiment, whole seedlings were enclosed in sealed chambers and air samples were withdrawn at 5 min intervals. Stimulated seedlings produced more ethylene than controls during the first 5 min interval, but not appreciably more during the second. This suggests the possibility that the ethylene production induced during the first 5 min occurs immediately rather than after a lag, and thus much too soon to be controlled by redistribution of IAA.

  5. Counterflow diffusion flames of hydrogen, and hydrogen plus methane, ethylene, propane, and silane vs. air - Strain rates at extinction

    NASA Technical Reports Server (NTRS)

    Pellett, G. L.; Northam, G. Burton; Wilson, L. G.

    1991-01-01

    Five coaxial tubular opposed jet burners (OJBs) with tube diameter D(T) of 1.8-10 mm and 5 mm conical nozzles were used to form dish-shaped counterflow diffusion flames centered by opposing laminar jets of nitrogen and hydrocarbon-diluted H2 versus air in an argon-purged chamber at 1 atm. Area-averaged air jet velocities at blowoff of the central flame, U(air), characterized extinction of the airside flame as functions of input H2 concentration on the fuelside. A master plot of extensive U(air) data at blowoff versus D(T) shows that U(air) varies linearly with D(T). This and other data sets are used to find that nozzle OJB results for U(air)/diameter average 4.24 + or - 0.28 times larger than tubular OJB results for the same fuel compositions. Critical radial velocity gradients consistent with one-dimensional stagnation point boundary theory and with plug flow inputs are estimated. The results compare favorably with published numerical results based only on potential flow.

  6. Protonated acetylene - An important circumstellar and interstellar ion

    NASA Technical Reports Server (NTRS)

    Glassgold, A. E.; Omont, A.; Guelin, M.

    1992-01-01

    In a circumstellar envelope, a substantial amount of acetylene is transported in a wind to the outer envelope, where it can be photoionized by interstellar radiation and then converted into C2H3(+) by a low-temperature reaction with H2. New chemical modeling calculations indicate that sufficient C2H3(+) may be produced in the outer envelope of IRC + 10216 to be observable. Similar considerations suggest that C2H3(+) should also be detectable in interstellar clouds, provided its rotational spectrum has been measured accurately in the laboratory.

  7. Magnetic coupling in a hybrid Mn(ii) acetylene dicarboxylate.

    PubMed

    Hendon, Christopher H; Pradaux-Caggiano, Fabienne; Hatcher, Lauren E; Gee, William J; Wilson, Chick C; Butler, Keith T; Carbery, David R; Walsh, Aron; Melot, Brent C

    2016-12-07

    The design of ligands that mediate through-bond long range super-exchange in metal-organic hybrid materials would expand chemical space beyond the commonly observed short range, low temperature magnetic ordering. Here we examine acetylene dicarboxylate as a potential ligand that could install long range magnetic ordering due to its spatially continuous frontier orbitals. Using a known Mn(ii)-containing coordination polymer we compute and measure the electronic structure and magnetic ordering. In this case, the latter is weak owing to the sub-optimal ligand coordination geometry, with a critical temperature of 2.5 K.

  8. Ultrafast hydrogen migration in acetylene cation driven by non-adiabatic effects.

    PubMed

    Madjet, Mohamed El-Amine; Li, Zheng; Vendrell, Oriol

    2013-03-07

    Non-adiabatic dynamics of the acetylene cation is investigated using mixed quantum-classical dynamics based on trajectory surface hopping. To describe the non-adiabatic effects, two surface hopping methods are used, namely, Tully's fewest switches and Landau-Zener surface hopping. Similarities and differences between the results based on those two methods are discussed. We find that the photoionization of acetylene into the first excited state A(2)Σg(+) drives the molecule from the linear structure to a trans-bent structure. Through a conical intersection the acetylene cation can relax back to either the ground state of acetylene or vinylidene. We conclude that hydrogen migration always takes place after non-radiative electronic relaxation to the ground state of the monocation. Based on the analysis of correlation functions we identify coherent oscillations between acetylene and vinylidene with a period of about 70 fs after the electronic relaxation.

  9. Suicidal inactivation and labelling of ammonia mono-oxygenase by acetylene.

    PubMed Central

    Hyman, M R; Wood, P M

    1985-01-01

    Acetylene brings about a progressive inactivation of ammonia mono-oxygenase, the ammonia-oxidizing enzyme in Nitrosomonas europaea. High NH4+ ion concentrations were protective. The inactivation followed first-order kinetics, with a rate constant of 1.5 min-1 at saturating concentrations of acetylene. If acetylene was added in the absence of O2, the cells remained active until O2 was re-introduced. A protective effect was also demonstrated with thiourea, a reversible non-competitive inhibitor of ammonia oxidation. Incubation of cells with [14C]acetylene was found to cause labelling of a single membrane polypeptide. This ran on dodecyl sulphate/polyacrylamide-gel electrophoresis with an Mr value of 28 000. It is concluded that acetylene is a suicide substrate for the mono-oxygenase. The labelling experiment provides the first identification of a constituent polypeptide of ammonia mono-oxygenase. Images Fig. 4. PMID:4004794

  10. Vibrational characterization of ethylene adsorption and its thermal evolution on Si(001)-(2 x 1): identification of majority and minority species.

    PubMed

    Kostov, Krassimir L; Nathaniel, Rachel; Mineva, Tzonka; Widdra, Wolf

    2010-08-07

    The vibrational and structural properties of a single-domain Si(001)-(2 x 1) surface upon ethylene adsorption have been studied by density functional cluster calculations and high-resolution electron energy loss spectroscopy. The detailed analysis of the theoretically and the experimentally determined vibrational frequencies reveals two coexisting adsorbate configurations. The majority species consist of ethylene molecules which are di-sigma bonded to the two Si atoms of a single Si-Si dimer. The local symmetry of this adsorption complex is reduced to C(2) for ethylene saturation coverage as determined by surface selection rules for the vibrational excitation process. The symmetry reduction includes the rotation of the C-C bond around the surface normal and the twist of the methylene groups around the C-C axis. Experimentally, 17 ethylene-derived modes are found and assigned for the majority and the minority species based on a comparison with calculated vibrational frequencies. The minority species which can account up to 14% of the total ethylene coverage is spectroscopically identified for the first time. It is assigned to ethylene molecules di-sigma bonded to two adjacent Si-Si dimers (in an end-bridge configuration). One part of the minority species desorbs molecularly at 665 K, about 50 K higher than the majority species, whereas the remaining part dissociates to adsorbed acetylene at temperatures around 630 K. For the latter, a di-sigma end-bridge like bonding configuration is proposed based on a comparison with vibrational data for adsorbed acetylene on Si(100)-(2 x 1).

  11. Performance of an Experimental Annular Turbojet Combustor with Methane and Propane

    NASA Technical Reports Server (NTRS)

    Norgren, Carl T

    1957-01-01

    Combustion efficiencies obtained with gaseous methane were compared with reported data obtained with gaseous propane for the same experimental combustor configuration. The combustion efficiencies obtained with methane were 98, 91, and 77 percent at simulated flight altitudes of 56,000, 70,000 and 80,000 feet, corresponding to combustor inlet-air pressures from 15 to 5 inches of mercury absolute. Combustion efficiencies with propane were equivalent to those with methane up to a simulated altitude of 70,000 feet. At the most severe conditions investigated propane operated with a higher efficiency and over a wider range of fuel-air ratio than methane.

  12. Variation of the pressure limits of flame propagation with tube diameter for propane-air mixtures

    NASA Technical Reports Server (NTRS)

    Belles, Frank E; Simon, Dorothy M

    1951-01-01

    An investigation was made of the variation of the pressure limits of flame propagation with tube diameter for quiescent propane with tube diameter for quiescent propane-air mixtures. Pressure limits were measured in glass tubes of six different inside diameters, with a precise apparatus. Critical diameters for flame propagation were calculated and the effect of pressure was determined. The critical diameters depended on the pressure to the -0.97 power for stoichiometric mixtures. The pressure dependence decreased with decreasing propane concentration. Critical diameters were related to quenching distance, flame speeds, and minimum ignition energy.

  13. On the Radiolysis of Ethylene Ices by Energetic Electrons and Implications to the Extraterrestrial Hydrocarbon Chemistry

    NASA Astrophysics Data System (ADS)

    Zhou, Li; Maity, Surajit; Abplanalp, Matt; Turner, Andrew; Kaiser, Ralf I.

    2014-07-01

    The chemical processing of ethylene ices (C2H4) by energetic electrons was investigated at 11 K to simulate the energy transfer processes and synthesis of new molecules induced by secondary electrons generated in the track of galactic cosmic ray particles. A combination of Fourier transform infrared spectrometry (solid state) and quadrupole mass spectrometry (gas phase) resulted in the identification of six hydrocarbon molecules: methane (CH4), the C2 species acetylene (C2H2), ethane (C2H6), the ethyl radical (C2H5), and—for the very first time in ethylene irradiation experiments—the C4 hydrocarbons 1-butene (C4H8) and n-butane (C4H10). By tracing the temporal evolution of the newly formed molecules spectroscopically online and in situ, we were also able to fit the kinetic profiles with a system of coupled differential equations, eventually providing mechanistic information, reaction pathways, and rate constants on the radiolysis of ethylene ices and the inherent formation of smaller (C1) and more complex (C2, C4) hydrocarbons involving carbon-hydrogen bond ruptures, atomic hydrogen addition processes, and radical-radical recombination pathways. We also discuss the implications of these results on the hydrocarbon chemistry on Titan's surface and on ice-coated, methane-bearing interstellar grains as present in cold molecular clouds such as TMC-1.

  14. Ethylene monitoring and control system

    NASA Technical Reports Server (NTRS)

    Nelson, Bruce N. (Inventor); Richard, II, Roy V. (Inventor); Kane, James A. (Inventor)

    2001-01-01

    A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

  15. Ethylene monitoring and control system

    NASA Technical Reports Server (NTRS)

    Nelson, Bruce N. (Inventor); Richard, II, Roy V. (Inventor); Kanc, James A. (Inventor)

    2000-01-01

    A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

  16. Ethylene-producing bacteria that ripen fruit.

    PubMed

    Digiacomo, Fabio; Girelli, Gabriele; Aor, Bruno; Marchioretti, Caterina; Pedrotti, Michele; Perli, Thomas; Tonon, Emil; Valentini, Viola; Avi, Damiano; Ferrentino, Giovanna; Dorigato, Andrea; Torre, Paola; Jousson, Olivier; Mansy, Sheref S; Del Bianco, Cristina

    2014-12-19

    Ethylene is a plant hormone widely used to ripen fruit. However, the synthesis, handling, and storage of ethylene are environmentally harmful and dangerous. We engineered E. coli to produce ethylene through the activity of the ethylene-forming enzyme (EFE) from Pseudomonas syringae. EFE converts a citric acid cycle intermediate, 2-oxoglutarate, to ethylene in a single step. The production of ethylene was placed under the control of arabinose and blue light responsive regulatory systems. The resulting bacteria were capable of accelerating the ripening of tomatoes, kiwifruit, and apples.

  17. State heating oil and propane program: Final report. Survey of No.2 heating oil and propane prices at the retail level, October 1997 through March 1998

    SciTech Connect

    1998-11-01

    The Energy Efficiency Division of the Vermont Department of Public Service (DPS) monitored the price and inventory of residential heating oil and propane during the 1997--98 heating season under a grant from the US Department of Energy`s Energy Information Administration (EIA). DPS staff collected data biweekly between October 5, 1997 and March 16, 1998 on the retail price of {number_sign}2 home heating oil and propane by telephone survey. Propane price quoted was based on the rate for a residential home heating customer using 1,000+ per year. The survey included a sample of fuel dealers selected by the EIA, plus additional dealers and fuels selected by the DPS. The EIA weighted, analyzed, and reported the data collected from their sample.

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

    USGS Publications Warehouse

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

    2008-01-01

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

  19. Acetylene as Fast Food: Implications for Development of Life on Anoxic Primordial Earth and in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Oremland, Ronald S.; Voytek, Mary A.

    2008-02-01

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

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

    PubMed

    Oremland, Ronald S; Voytek, Mary A

    2008-02-01

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

  1. Burning of the Supersonic Propane-Air Mixture in the Aerodynamic Channel With the Stagnant Zone

    DTIC Science & Technology

    2007-11-02

    V.Chernikov, V.Shibkov, O.Surkont. Mechanisms of transversal electric discharge sustention in supersonic air and propane-air flows. -American Institute of Aeronautics and Astronautics, AIAA Paper, 2003, No.03-0872, p. 1 -6 .

  2. Short-Term Energy Outlook Model Documentation: Regional Residential Propane Price Model

    EIA Publications

    2009-01-01

    The regional residential propane price module of the Short-Term Energy Outlook (STEO) model is designed to provide residential retail price forecasts for the 4 Census regions: Northeast, South, Midwest, and West.

  3. PHYSICAL PROPERTIES OF FLUORINATED PROPANE AND BUTANE DERIVATIVES AS ALTERNATIVE REFRIGERANTS

    EPA Science Inventory

    Physical property measurements are presented for 24 fluorinated propane and butane derivatives and one fluorinated ether. These measurements include melting point, boiling point, vapor pressure below the boiling point, heat of vaporization at the boiling point, critical propertie...

  4. School Districts Move to the Head of the Class with Propane

    SciTech Connect

    2016-01-01

    Propane has been a proven fuel for buses for decades. For the first time in 2007, Blue Bird rolled out a propane school bus using direct liquid injection, which was later followed by Thomas Built Buses and Navistar. Because this new technology is much more reliable than previous designs, it is essentially reintroducing propane buses to many school districts. During this same time period, vehicle emissions standards have tightened. To meet them, diesel engine manufacturers have added diesel particulate filters (DPF) and, more recently, selective catalytic reduction (SCR) systems. As an alternative to diesel buses with these systems, many school districts have looked to other affordable, clean alternatives, and they've found that propane fits the bill.

  5. Effect of preprocessing and compressed propane extraction on quality of cilantro (Coriandrum sativum L.).

    PubMed

    Sekhon, Jasreen K; Maness, Niels O; Jones, Carol L

    2015-05-15

    Dehydration leads to quality defects in cilantro such as loss in structure, color, aroma and flavor. Solvent extraction with compressed propane may improve the dehydrated quality. In the present study, effect of drying temperature, particle size, and propane extraction on color, volatile composition, and fatty acid composition of cilantro was evaluated. Cilantro was dehydrated (40°C or 60°C), size reduced and separated into three particles sizes, and extracted with compressed propane at 21-27°C. Major volatile compounds found in dried cilantro were E-2-tetradecenal, dodecanal, E-2-dodecenal, and tetradecanal. Major fatty acids were linoleic acid and α-linolenic acid. Drying at 60°C compared to 40°C resulted in better preservation of color (decrease in browning index values) and volatile compounds. Propane extraction led to a positive change in color values and a decrease in volatile composition, oil content, and fatty acid composition.

  6. Deposit formation in hydrocarbon rocket fuels with an evaluation of a propane heat transfer correlation

    NASA Technical Reports Server (NTRS)

    Masters, P. A.; Aukerman, C. A.

    1982-01-01

    A high pressure fuel coking testing apparatus was designed and developed and was used to evaluate thermal decomposition limits and carbon decomposition rates in heated copper tubes for hydrocarbon fuels. A commercial propane (90% grade) and chemically pure (CP) propane were tested. Heat transfer to supercritical propane was evaluated at 136 atm, bulk fluid velocities of 6 to 30 m/s, and tube wall temperatures in the range of 422 to 811 K. A forced convection heat transfer correlation developed in a previous test effort verified a prediction of most of the experimental data within a + or - 30% range, with good agreement for the CP propane data. No significant differences were apparent in the predictions derived from the correlation when the carbon resistance was included with the film resistance. A post-test scanning electron microprobe analysis indicated occurrences of migration and interdiffusion of copper into the carbon deposit.

  7. [The development of acetylene on-line monitoring technology based on laser absorption spectrum].

    PubMed

    He, Ying; Zhang, Yu-jun; Kan, Rui-feng; Xia, Hui; Wang, Min; Cui, Xiao-juan; Chen, Jiu-ying; Chen, Dong; Liu, Wen-qing; Liu, Jian-guo

    2008-10-01

    As one of the materials in organic chemical industry, acetylene has been used in many aspects of chemical industry. But acetylene is a very dangerous inflammable and explosive gas, so it needs in-situ monitoring during industrial storage and production. Tunable diode laser absorption spectroscopy (TDLAS) technology has been widely used in atmospheric trace gases detection, because it has a lot of advantageous characteristics, such as high sensitivity, good selectivity, and rapid time response. The distribution characteristics of absorption lines of acetylene in near infrared band were studied, and then the system designing scheme of acetylene on-line monitoring based on near infrared tunable diode laser absorption spectroscopy technology was discussed in detail. Moreover, the system of experiment measurement was set up and the method of signal detection and the algorithm of concentration inversion were studied. In addition, the sample cell with a path length of 10 cm, and the acetylene of different known concentrations were measured. As a result, the detection limit obtained reached 1.46 cm3 x m(-3). Finally the dynamic detection experiment was carried out, and the measurement result is stable and reliable, so the design of the system is practicable through experiment analysis. On-line acetylene leakage monitoring system was developed based on the experiment, and it is suitable for giving a leakage alarm of acetylene during its storage, transportation and use.

  8. Real-time monitoring of nucleation-growth cycle of carbon nanoparticles in acetylene plasmas

    NASA Astrophysics Data System (ADS)

    Hundt, Morten; Sadler, Patrick; Levchenko, Igor; Wolter, Matthias; Kersten, Holger; Ostrikov, Kostya (Ken)

    2011-06-01

    Quantum cascade laser absorption spectroscopy was used to measure the absolute concentration of acetylene in situ during the nanoparticle growth in Ar + C2H2 RF plasmas. It is demonstrated that the nanoparticle growth exhibits a periodical behavior, with the growth cycle period strongly dependent on the initial acetylene concentration in the chamber. Being 300 s at 7.5% of acetylene in the gas mixture, the growth cycle period decreases with the acetylene concentration increasing; the growth eventually disappears when the acetylene concentration exceeds 32%. During the nanoparticle growth, the acetylene concentration is small and does not exceed 4.2% at radio frequency (RF) power of 4 W, and 0.5% at RF power of 20 W. An injection of a single acetylene pulse into the discharge also results in the nanoparticle nucleation and growth. The absorption spectroscopy technique was found to be very effective for the time-resolved measurement of the hydrocarbon content in nanoparticle-generating plasmas.

  9. School Districts Move to the Head of the Class with Propane

    SciTech Connect

    2016-01-12

    School districts across the country are under pressure to reduce their cost of operations and ensure their budgets are spent wisely. School bus fleets operate more than 675,000 buses in the United States, and many school districts have found the answer to their budget woes in the form of propane, or liquefied petroleum gas (LPG). Propane is a reliable, domestic fuel, and it's used in approximately 2% of school buses nationwide.

  10. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: cluster ion polymerization.

    PubMed

    Kočišek, J; Lengyel, J; Fárník, M

    2013-03-28

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of ≈8%, while mixed species are produced at low concentrations (≈0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C2H2)n(+). At the electron energies ≥21.5 eV above the CH+CH(+) dissociative ionization limit of acetylene the fragment ions nominally labelled as (C2H2)nCH(+), n ≥ 2, are observed. For n ≤ 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C2H2)n - k × H](+) and [(C2H2)nCH - k × H](+). The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C3H3(+) ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of ≈13.7 eV indicates that a less rigid covalently bound structure of C6H6(+) ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Arn(C2H2)(+) fragments above ≈15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Arn≥2(C2H2)m≥2(+) at ≈13.7 eV is discussed in terms of an exciton transfer mechanism.

  11. Analysis of acetylene in blood and urine using cryogenic gas chromatography-mass spectrometry.

    PubMed

    Kashiwagi, Masayuki; Hara, Kenji; Fujii, Hiroshi; Kageura, Mitsuyoshi; Takamoto, Mutsuo; Matsusue, Aya; Sugimura, Tomoko; Kubo, Shin-ichi

    2009-09-01

    A method for quantitative analysis of acetylene in blood and urine samples was investigated. Using cryogenic gas chromatography-mass spectrometry (GC-MS), acetylene was measured with isobutane as the internal standard in the headspace method, which revealed a linear response over the entire composite range with an excellent correlation coefficient, both in blood (R = 0.9968, range = 5.39-43.1 microg/ml) and urine (R = 0.9972, range = 2.16-10.8 microg/ml). The coefficients of variation (CV) for blood ranged from 2.62 to 11.6% for intra-day and 4.55 to 10.4% for inter-day. The CV for urine ranged from 2.38 to 3.10% for intra-day and 4.83 to 11.0% for inter-day. The recovery rate as an index of accuracy ranged from 83 to 111%. The present method showed good reliability, and is also simple and rapid. In actual samples from a charred cadaver due to acetylene explosion, the measured concentrations of acetylene by this method were 21.5 microg/ml for femoral vein blood, 17.9 microg/ml for right atrial blood, 25.5 microg/ml for left atrial blood and 7.49 microg/ml for urine. Quantification of acetylene provides important information, because the acetylene concentration is a vital reaction or sign. For example, when acetylene is filled in a closed space and then explodes, in antemortem explosion, the blood acetylene concentration of the cadaver might be significant. On the other hand, in postmortem explosion, acetylene is not detected in blood. Furthermore, when several victims are involved in one explosion, comparison of the sample concentrations can also provide useful information to establish the conditions at the accident scene; therefore, the present method is useful in forensics.

  12. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: Cluster ion polymerization

    NASA Astrophysics Data System (ADS)

    Kočišek, J.; Lengyel, J.; Fárník, M.

    2013-03-01

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of ≈8%, while mixed species are produced at low concentrations (≈0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C_2H_2)_n^+. At the electron energies ⩾21.5 eV above the CH+CH+ dissociative ionization limit of acetylene the fragment ions nominally labelled as (C2H2)nCH+, n ⩾ 2, are observed. For n ⩽ 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C2H2)n - k × H]+ and [(C2H2)nCH - k × H]+. The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C3 H_3^+ ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of ≈13.7 eV indicates that a less rigid covalently bound structure of C6 H_6^+ ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Arn(C2H2)+ fragments above ≈15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Ar_{n ≥ 2}(C2 H2)_{m≥ 2}^+ at ≈13.7 eV is discussed in terms of an exciton transfer mechanism.

  13. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    EPA Pesticide Factsheets

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

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

    SciTech Connect

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

    2000-04-08

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

  15. Effects of Air/Nitrogen Cure on An Acetylene Terminated Quinoxaline Thermoset System

    DTIC Science & Technology

    1981-06-01

    AFWAL-TR-81-401 2 FILE Copy EFFECTS OF AIR/NITROGEN CURE ON AN ACETYLENE TERMINATED QUINOXALINE THERMOSET SYSTEM Polymer Branch Nonmetallic Materials...RECIPIENT’S CATALOG NUMBER AFWAL-TR- 81-4012 4. TITLE (and Subtitle) 5. TYPE OF REPORT & PERIOD COVERED Effects of Air/Nitrogen Cure on an Acetylene ...81-4012 SECTION I INTRODUCTION The Air Force has an interest in the development of acetylene - terminated (AT) resins as a new technology to form high

  16. Acetylene in breath: background levels and real-time elimination kinetics after smoking.

    PubMed

    Metsälä, M; Schmidt, F M; Skyttä, M; Vaittinen, O; Halonen, L

    2010-12-01

    We have measured the acetylene concentration in the exhaled breath of 40 volunteers (31 non-smokers, nine smokers) using near-infrared cavity ring-down spectroscopy. The acetylene levels were found to be the same as in ambient air for non-smokers, whereas elevated levels were observed for smokers. Real-time measurements with sub-second time resolution have been applied to measure the elimination kinetics of acetylene in breath after exposure to tobacco smoke. Three exponential time constants can be distinguished from the data and these can be used to define the residence times for different compartments, according to the multi-compartment model of the human body.

  17. Acetylene as a substrate in the development of primordial bacterial communities

    USGS Publications Warehouse

    Culbertson, C.W.; Strohmaier, F.E.; Oremland, R.S.

    1988-01-01

    The fermentation of atmospheric acetylene by anaerobic bacteria is proposed as the basis of a primordial heterotrophic food chain. The accumulation of fermentation products (acetaldehyde, ethanol, acetate and hydrogen) would create niches for sulfate-respiring bacteria as well as methanogens. Formation of acetylene-free environments in soils and sediments would also alter the function of nitrogenase from detoxification to nitrogen-fixation. The possibility of an acetylene-based anaerobic food chain in Jovian-type atmospheres is discussed. ?? 1988 Kluwer Academic Publishers.

  18. Ethylene binding site affinity in ripening apples

    SciTech Connect

    Blankenship, S.M. . Dept. of Horticultural Science); Sisler, E.C. )

    1993-09-01

    Scatchard plots for ethylene binding in apples (Malus domestica Borkh.), which were harvested weekly for 5 weeks to include the ethylene climacteric rise, showed C[sub 50] values (concentration of ethylene needed to occupy 50% of the ethylene binding sites) of 0.10, 0.11, 0.34, 0.40, and 0.57 [mu]l ethylene/liter[sup [minus]1], respectively, for each of the 5 weeks. Higher ethylene concentrations were required to saturate the binding sites during the climacteric rise than at other times. Diffusion of [sup 14]C-ethylene from the binding sites was curvilinear and did not show any indication of multiple binding sites. Ethylene was not metabolized by apple tissue.

  19. Colorometric detection of ethylene glycol vapor

    NASA Technical Reports Server (NTRS)

    Helm, C.; Mosier, B.; Verostko, C. E.

    1970-01-01

    Very low concentrations of ethylene glycol in air or other gases are detected by passing a sample through a glass tube with three partitioned compartments containing reagents which successively convert the ethylene glycol vapor into a colored compound.

  20. Spectroscopic studies of cryogenic fluids: Benzene in propane

    NASA Astrophysics Data System (ADS)

    Nowak, R.; Bernstein, E. R.

    1987-03-01

    Energy shifts and bandwidths for the 1B2u↔1A1g optical absorption and emission transitions of benzene dissolved in propane are presented as a function of pressure, temperature, and density. Both absorption and emission spectra exhibit shifts to lower energy as a function of density, whereas no shifts are observed if density is kept constant and temperature and pressure are varied simultaneously. Density is thus the fundamental microscopic parameter for energy shifts of optical transitions. The emission half-width is a linear function of both temperature and pressure but the absorption half-width is dependent only upon pressure. These results are interpreted qualitatively in terms of changes occurring in the intermolecular potentials of the ground and excited states. Both changes in shape of and separation between the ground and excited state potentials are considered as a function of density. Classical dielectric (Onsager-Böttcher), microscopic dielectric (Wertheim) and microscopic quantum statistical mechanical (Schweizer-Chandler) theories of solvent effects on solute electronic spectra are compared with the experimental results. Calculations suggest limited applicability of dielectric theories but good agreement between experiment and microscopic theory. The results demonstrate the usefulness of cryogenic solutions for high pressure, low temperature spectroscopic studies of liquids.

  1. Infrared Spectra and Optical Constants of Astronomical Ices: II. Ethane and Ethylene

    NASA Technical Reports Server (NTRS)

    Hudson, Reggie L.; Gerakines, Perry A.; Moore, M. H.

    2014-01-01

    Infrared spectroscopic observations have established the presence of hydrocarbon ices on Pluto and other TNOs, but the abundances of such molecules cannot be deduced without accurate optical constants (n, k) and reference spectra. In this paper we present our recent measurements of near- and mid-infrared optical constants for ethane (C2H6) and ethylene (C2H4) in multiple ice phases and at multiple temperatures. As in our recent work on acetylene (C2H2), we also report new measurements of the index of refraction of each ice at 670 nm. Comparisons are made to earlier work where possible, and electronic versions of our new results are made available.

  2. Volatilization of ethylene dibromide from water

    USGS Publications Warehouse

    Rathbun, R.E.; Tai, D.Y.

    1987-01-01

    Overall mass-transfer coefficients for the volatilization of ethylene dibromide from water were measured simultaneously with the oxygen absorption coefficient in a laboratory stirred tank. Coefficients were measured as a function of mixing conditions in the water for two windspeeds. The ethylene dibromide mass-transfer coefficient depended on windspeed; the ethylene dibromide liquid-film coefficient did not, in agreement with theory. A constant relation existed between the liquid-film coefficients for ethylene dibromide and oxygen.

  3. Investigation on Novel Methods to Increase Specific Thrust in Pulse Detonation Engines via Imploding Detonations

    DTIC Science & Technology

    2009-12-01

    to-Detonation Transition, Specific Thrust 16. PRICE CODE 17. SECURITY CLASSIFICATION OF REPORT Unclassified 18. SECURITY CLASSIFICATION OF THIS...hydrocarbon fuel-air mixtures such as acetylene -air, ethylene-air, propane-air and even JP10-air mixtures based on the required length of the induction zone

  4. Ultrafast Extreme Ultraviolet Induced Isomerization of Acetylene Cations

    SciTech Connect

    Jiang, Y. H.; Kurka, M.; Kuehnel, K. U.; Schroeter, C. D.; Moshammer, R.; Rudenko, A.; Foucar, L.; Herrwerth, O.; Lezius, M.; Kling, M. F.; Tilborg, J. van; Belkacem, A.; Ueda, K.; Duesterer, S.; Treusch, R.; Ullrich, J.

    2010-12-31

    Ultrafast isomerization of acetylene cations ([HC=CH]{sup +}) in the low-lying excited A{sup 2}{Sigma}{sub g}{sup +} state, populated by the absorption of extreme ultraviolet (XUV) photons (38 eV), has been observed at the Free Electron Laser in Hamburg, (FLASH). Recording coincident fragments C{sup +}+CH{sub 2}{sup +} as a function of time between XUV-pump and -probe pulses, generated by a split-mirror device, we find an isomerization time of 52{+-}15 fs in a kinetic energy release (KER) window of 5.8

  5. Decoupling in the line mixing of acetylene infrared Q branches

    NASA Technical Reports Server (NTRS)

    Pine, A. S.; Looney, J. P.

    1990-01-01

    A difference-frequency laser spectrometer was used to record the Q-branch profiles of the nu1 + nu5, nu3 + nu4, and nu2 + 2nu4 + nu5 Pi(u)-Sigma(g) combination bands in the 2.5 micron C-H stretch-bend region of acetylene. The experiment was carried out at pressures in the range of 1 to 500 Torr. It is shown that line mixing causes substantial deviation of collisionally overlapped Q-branch profiles from the independently additive superposition of Lorentzian line shapes. It is also found that the degree of line mixing is greatly reduced from that assuming all the broadening arises from rotationally inelastic collisions coupling Q-branch lines only to one another.

  6. Acetylene fuel from atmospheric CO2 on Mars

    NASA Technical Reports Server (NTRS)

    Landis, Geoffrey A.; Linne, Diane L.

    1992-01-01

    The Mars mission scenario proposed by Baker and Zubrin (1990) intended for an unmanned preliminary mission is extended to maximize the total impulse of fuel produced with a minimum mass of hydrogen from Earth. The hydrogen along with atmospheric carbon dioxide is processed into methane and oxygen by the exothermic reaction in an atmospheric processing module. Use of simple chemical reactions to produce acetylene/oxygen rocket fuel on Mars from hydrogen makes it possible to produce an amount of fuel that is nearly 100 times the mass of hydrogen brought from earth. If such a process produces the return propellant for a manned Mars mission, the required mission mass in LEO is significantly reduced over a system using all earth-derived propellants.

  7. Detection of acetylene in the infrared spectrum of comet Hyakutake

    NASA Technical Reports Server (NTRS)

    Brooke, T. Y.; Tokunaga, A. T.; Weaver, H. A.; Crovisier, J.; Bockelee-Morvan, D.; Crisp, D.

    1996-01-01

    Comets are rich in volatile materials, of which roughly 80% (by number) are water molecules. Considerable progress is being made in identifying the other volatile species, the abundances of which should enable us to determine whether comets formed primarily from ice-covered interstellar grains, or from material that was chemically processed in the early solar nebula. Here we report the detection of acetylene (C2H2) in the infrared spectrum of comet C/1996 B2 (Hyakutake). The estimated abundance is 0.3-0.9%, relative to water, which is comparable to the predicted solid-phase abundance in cold interstellar clouds. This suggests that the volatiles in comet Hyakotake may have come from ice-covered interstellar grains, rather than material processed in the accretion disk out of which the Solar System formed.

  8. Adhesive and composite evaluation of acetylene-terminated phenylquinoxaline resins

    NASA Technical Reports Server (NTRS)

    Hergenrother, P. M.

    1981-01-01

    A series of acetylene-terminated phenylquinoxaline (ATPQ) oligomers of various molecular weights were prepared and subsequently chain extended by the thermally induced reaction of the ethynyl groups. The processability and thermal properties of these oligomers and their cured resins were compared with that of a relatively high molecular weight linear polyphenylquinoxaline (PPQ) with the same chemical backbone. The ATPQ oligomers exhibited significantly better processability than the linear PPQ but the PPQ displayed substantially better thermooxidative stability. Adhesive (Ti/Ti) and composite (graphite filament reinforcement) work was performed to evaluate the potential of these materials for structural applications. The PPQ exhibited better retention of adhesive and laminate properties than the ATPQ resins at 260 C after aging for 500 hr at 260 C in circulating air.

  9. Ultrafast Extreme Ultraviolet Induced Isomerization of Acetylene Cations

    SciTech Connect

    Jiang, Y.; Rudenko, Artem; Herrwerth, O.; Foucar, L.; Kurka, M.; Kuhnel, K.; Lezius, M.; Kling, Matthias; van Tilborg, Jeroen; Belkacem, Ali; Ueda, K.; Dusterer, S.; Treusch, R.; Schroter, Claus-Dieter; Moshammer, Robbert; Ullrich, Joachim

    2011-06-17

    Ultrafast isomerization of acetylene cations ([HC = CH]{sup +}) in the low-lying excited A{sup 2}{Sigma}{sub g}{sup +} state, populated by the absorption of extreme ultraviolet (XUV) photons (38 eV), has been observed at the Free Electron Laser in Hamburg, (FLASH). Recording coincident fragments C{sup +} + CH{sub 2}{sup +} as a function of time between XUV-pump and -probe pulses, generated by a split-mirror device, we find an isomerization time of 52 {+-} 15 fs in a kinetic energy release (KER) window of 5.8 < KER < 8 eV, providing clear evidence for the existence of a fast, nonradiative decay channel.

  10. Organogermanium Chemistry: Germacyclobutanes and digermane Additions to Acetylenes

    SciTech Connect

    Chubb, Andrew Michael

    2003-01-01

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

  11. 49 CFR 173.323 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.323 Ethylene oxide. (a) For packaging ethylene oxide in non-bulk packagings, silver mercury or any of its alloys or copper may not be used in any... 49 Transportation 2 2012-10-01 2012-10-01 false Ethylene oxide. 173.323 Section...

  12. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used...

  13. 21 CFR 173.230 - Ethylene dichloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene dichloride. 173.230 Section 173.230 Food... Solvents, Lubricants, Release Agents and Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present...

  14. 21 CFR 173.230 - Ethylene dichloride.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene dichloride. 173.230 Section 173.230 Food... Solvents, Lubricants, Release Agents and Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present...

  15. 21 CFR 173.230 - Ethylene dichloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene dichloride. 173.230 Section 173.230 Food... Solvents, Lubricants, Release Agents and Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present...

  16. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used...

  17. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used...

  18. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used...

  19. 21 CFR 173.230 - Ethylene dichloride.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene dichloride. 173.230 Section 173.230 Food... Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present therein as a residue from the extraction of...

  20. 21 CFR 173.230 - Ethylene dichloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene dichloride. 173.230 Section 173.230 Food... Solvents, Lubricants, Release Agents and Related Substances § 173.230 Ethylene dichloride. A tolerance of 30 parts per million is established for ethylene dichloride in spice oleoresins when present...

  1. 21 CFR 573.440 - Ethylene dichloride.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Ethylene dichloride. 573.440 Section 573.440 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL... Additive Listing § 573.440 Ethylene dichloride. The food additive ethylene dichloride may be safely used...

  2. Liquid ethylene-propylene copolymers

    NASA Technical Reports Server (NTRS)

    Rhein, R. A.; Ingham, J. D.; Humphrey, M. F.

    1975-01-01

    Oligomers are prepared by heating solid ethylene-propylene rubber in container that retains solid and permits liquid product to flow out as it is formed. Molecular weight and viscosity of liquids can be predetermined by process temperature. Copolymers have low viscosity for given molecular weight.

  3. Silyl-acetylene polymers for use as precursors to silicon carbide fibers

    SciTech Connect

    Meyer, M.K.

    1991-12-20

    The steps involved in production of silicon carbide fiber using silyl acetylene polymer precursors can be separated into four processing steps: polymer synthesis, fiber spinning, fiber crosslinking, and pyrolysis. Practical experimental considerations in each step are discussed.

  4. KISS: Kinetics and Structure of Superagglomerates Produced by Silane and Acetylene

    NASA Technical Reports Server (NTRS)

    Mulholland, G. W.; Yang, J. C.; Scott, J. H.; Sivithanu, Y.

    2001-01-01

    The objective of this study is to understand the process of gas phase agglomeration leading to superagglomerates and a gel-like structure for microgravity (0-g) silane and acetylene flames. Ultimately one would apply this understanding to predicting flame conditions that could lead to the gas phase production of an aero-gel. The approach is to burn acetylene and silane and to analyze the evolution of the soot and silica agglomerates. Acetylene is chosen because it has one of the highest soot volume fractions and there is evidence of super agglomerates being formed in laminar acetylene flames. Silane has the advantage that silica particles are the major combustion product resulting in a particle volume fraction a factor of ten greater than that for a carbonaceous smoke.

  5. Fluorinated 5- and 7-membered carbacycle motifs by reaction of difluorocarbene with acetylene ethers.

    PubMed

    Chia, Poh Wai; Bello, Davide; Slawin, Alexandra M Z; O'Hagan, David

    2013-03-18

    The reaction of acetylene ethers with difluorocarbene (CF(2)), generated from the Ruppert-Prakash reagent, unexpectedly gave rise to co-produced fluorinated bicyclic [2.1.1]-hex-2-ene and cyclohepta-1,4-diene ring products.

  6. INHIBITION OF ALKYLBENZENE BIODEGRADATION UNDER DENITRIFYING CONDITIONS BY USING THE ACETYLENE BLOCK TECHNIQUE

    EPA Science Inventory

    Addition of acetylene to microcosms simultaneously amended with nitrate and alkylbenzenes resulted in inhibition of the rate of alkylbenzene biodegradation under denitrifying conditions. Toluene, xylenes, and 1,2,4-trimethylbenzene were recalcitrant, whereas ethylbenzene was degr...

  7. Tunable mid-infrared emission from acetylene-filled hollow-core fiber

    NASA Astrophysics Data System (ADS)

    Wang, Zefeng; Zhou, Zhiyue; Li, Zhixian; Zhang, Naiqian; Chen, Yubin

    2016-11-01

    We report here a step tunable mid-infrared laser emission from acetylene-filled hollow-core fiber. Two kinds of anti-resonant hollow-core fibers are filled with mbar level of acetylene gas, and pumped with a modulated, amplified, narrow linewidth, fine tunable, 1.5 μm diode laser, then 3 μm laser emissions are generated by the intrinsic absorption of acetylene molecules. The laser wavelength is step-tunable in the range of 3.1 3.2 μm when the pump laser is precisely tuned to different absorption lines of P-branch of acetylene. By properly designing the fiber's transmission bands, and carefully selecting active gases and pump lasers, this paper provides a novel method for efficient, compact and tunable mid-infrared fiber lasers over a broad spectrum range.

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

    NASA Technical Reports Server (NTRS)

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

    2011-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2012-01-01

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

  10. Characterization of the Minimum Energy Paths and Energetics for the Reaction of Vinylidene with Acetylene

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Taylor, Peter R.

    1995-01-01

    The reaction of vinylidene (CH2C) with acetylene may be an initiating reaction in soot formation. We report minimum energy paths and accurate energetics for a pathway leading to vinyl-acetylene and for a number of isomers of C4H4. The calculations use complete active space self-consistent field (CASSCF) derivative methods to characterize the stationary points and internally contacted configuration interaction (ICCI) and/or coupled cluster singles and doubles with a perturbational estimate of triple excitations (CCSD(T)) to determine the energetics. We find an entrance channel barrier of about 5 kcal/mol for the addition of vinylidene to acetylene, but no barriers above reactants for the reaction pathway leading to vinyl-acetylene.

  11. Ethylene effects in pea stem tissue

    SciTech Connect

    Steen, D.A.; Chadwick, A.V.

    1981-01-01

    The marked effects of ethylene on pea stem growth have been investigated. Low temperatures and colchicine, both known microtubule depolymerization agents, reverse the effects of ethylene in straight growth tests. Low temperature (6 C) also profoundly reduces the effects of gas in terms of swelling, hook curvature, and horizontal mutation. Deuterium oxide, an agent capable of rigidifying microtubular structure, mimics the effects of ethylene. Electron microscopy shows that microtubule orientation is strikingly altered by ethylene. These findings indicate that some of the ethylene responses may be due to a stabilizing effect on microtubules in plant cells.

  12. Assessment of the risk of transporting propane by truck and train

    SciTech Connect

    Geffen, C.A.

    1980-03-01

    The risk of shipping propane is discussed and the risk assessment methodology is summarized. The risk assessment model has been constructed as a series of separate analysis steps to allow the risk to be readily reevaluated as additional data becomes available or as postulated system characteristics change. The transportation system and accident environment, the responses of the shipping system to forces in transportation accidents, and release sequences are evaluated to determine both the likelihood and possible consequences of a release. Supportive data and analyses are given in the appendices. The risk assessment results are related to the year 1985 to allow a comparison with other reports in this series. Based on the information presented, accidents involving tank truck shipments of propane will be expected to occur at a rate of 320 every year; accidents involving bobtails would be expected at a rate of 250 every year. Train accidents involving propane shipments would be expected to occur at a rate of about 60 every year. A release of any amount of material from propane trucks, under both normal transportation and transport accident conditions, is to be expected at a rate of about 110 per year. Releases from propane rail tank cars would occur about 40 times a year. However, only those releases that occur during a transportation accident or involve a major tank defect will include sufficient propane to present the potential for danger to the public. These significant releases can be expected at the lower rate of about fourteen events per year for truck transport and about one event every two years for rail tank car transport. The estimated number of public fatalities resulting from these significant releases in 1985 is fifteen. About eleven fatalities per year result from tank truck operation, and approximately half a death per year stems from the movement of propane in rail tank cars.

  13. Lean and ultralean stretched propane-air counterflow flames

    SciTech Connect

    Cheng, Zhongxian; Pitz, Robert W.; Wehrmeyer, Joseph A.

    2006-06-15

    Stretched laminar flame structures for a wide range of C{sub 3}H{sub 8}-air mixtures vs hot products are investigated by laser-based diagnostics and numerical simulation. The hot products are produced by a lean H{sub 2}-air premixed flame. The effect of stretch rate and equivalence ratio on four groups of C{sub 3}H{sub 8}-air flame structures is studied in detail by Raman scattering measurements and by numerical calculations of the major species concentration and temperature profiles. The equivalence ratio, f, is varied from a near-stoichiometric condition (f=0.86) to the sublean limit (f=0.44) and the stretch rate varies from 90 s{sup -1} to near extinction. For most of these C{sub 3}H{sub 8}-air lean mixtures, hot products are needed to maintain the flame. The significant feature of these flames is the relatively low flame temperatures (1200-1800 K). For this temperature range, the predicted C{sub 3}H{sub 8}-air flame structure is sensitive to the specific chemical kinetic mechanism. Two types of flame structures (a lean self-propagating flame and a lean diffusion-controlled flame) are obtained based on the combined effect of stretch and equivalence ratio. Three different mechanisms, the M5 mechanism, the Optimized mechanism, and the San Diego mechanism, are chosen for the numerical simulations. None of the propane chemical mechanisms give good agreement with the data over the entire range of flame conditions. (author)

  14. Enhanced ethylene and ethane production with free-radical cracking catalysts.

    PubMed

    Kolts, J H; Delzer, G A

    1986-05-09

    A series of free-radical catalysts have been discovered that increase the yield of highly valuable olefins from the cracking of low molecular weight paraffins. For example, catalytic cracking of n-butane, isobutane, and propane over manganese or iron supported on magnesium oxide (MgO) gave product distributions different from those given by thermal (free-radical) cracking or cracking over traditional acid catalysts. With n-butane and propane feeds, the products from catalytic cracking included large amounts of ethylene and ethane; with isobutane feed, propylene was the major product. Physical characterization of the MgO-supported catalyst showed the manganese to be in a 2+ oxidation state in the reduced catalyst and a 4+ oxidation state in the fully oxidized catalyst. Manganese was also shown to be uniformly distributed in the support material with very little enrichment at the surface. Matrix isolation of the gasphase radicals from n-butane feed showed that ethyl and methyl radicals were produced over the active catalysts. In the thermal process, only methyl radicals were produced. The mechanism of the catalytic reaction appears to be selective formation of primary carbanions at the catalyst surface followed by electron transfer and release of primary hydrocarbon radicals to the gas phase.

  15. The adsorption of acetylene on rhodium-modified colloidal silver, a surface-enhanced Raman study

    NASA Astrophysics Data System (ADS)

    Feilchenfeld, Hannah; Luckier, Miguel; Efron, Leah; Willner, Bilha

    Surface-enhanced Raman scattering (SERS) from molecules adsorbed on rhodium-modified colloidal silver particles is reported for the first time. Deposition of thin layers of metallic rhodium on the silver surface led to fast aggregation of the sol and to modifications of its SERS spectrum. An intense new band, assigned to the RhO stretching vibration of citrate ions bound to rhodium sites, appeared at 530 cm -1 in the Raman spectrum after rhodium addition to the suspension. The spectra of acetylene adsorbed on both unmodified silver particles and silver modified by an overlayer of rhodium indicated that acetylene displaced the citrate ions from their adsorption sites. All acetylene spectra were characterized by weak bands at 1990, 2050 and 2150 cm -1 assigned to σ π-complexes between acetylene and silver, by a silver acetylide peak at 1800 cm -1 and by an intense band at 1550 cm -1 due to C=C containing species formed on the surface. However, on the rhodium-modified colloid an additional band, attributed to acetylene σ π-bound to rhodium sites, was observed at 1910-1920 cm -1. The intensity of the new band was a direct function of the amount of rhodium deposited on the silver. It increased immediately after acetylene adsorption, and later slowly diminished, while simultaneously the 1550 cm -1 peak became more important. This time evolution was ascribed to a reaction taking place on the surface.

  16. A porous metal-organic framework with ultrahigh acetylene uptake capacity under ambient conditions

    PubMed Central

    Pang, Jiandong; Jiang, Feilong; Wu, Mingyan; Liu, Caiping; Su, Kongzhao; Lu, Weigang; Yuan, Daqiang; Hong, Maochun

    2015-01-01

    Acetylene, an important petrochemical raw material, is very difficult to store safely under compression because of its highly explosive nature. Here we present a porous metal-organic framework named FJI-H8, with both suitable pore space and rich open metal sites, for efficient storage of acetylene under ambient conditions. Compared with existing reports, FJI-H8 shows a record-high gravimetric acetylene uptake of 224 cm3 (STP) g−1 and the second-highest volumetric uptake of 196 cm3 (STP) cm−3 at 295 K and 1 atm. Increasing the storage temperature to 308 K has only a small effect on its acetylene storage capacity (∼200 cm3 (STP) g−1). Furthermore, FJI-H8 exhibits an excellent repeatability with only 3.8% loss of its acetylene storage capacity after five cycles of adsorption–desorption tests. Grand canonical Monte Carlo simulation reveals that not only open metal sites but also the suitable pore space and geometry play key roles in its remarkable acetylene uptake. PMID:26123775

  17. Mechanism-based inactivation of benzo(a)pyrene hydroxylase by aryl acetylenes and aryl olefins

    SciTech Connect

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

    1986-05-01

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

  18. Divergent Metabolic Pathways for Propane and Propionate Utilization by a Soil Isolate1

    PubMed Central

    Vestal, J. R.; Perry, Jerome J.

    1969-01-01

    The metabolism of propane and propionate by a soil isolate (Brevibacterium sp. strain JOB5) was investigated. The presence of isocitrate lyase in cells grown on isopropanol, acetate, or propane and the absence of this inducible enzyme in n-propanol- and propionate-grown cells suggested that propane is not metabolized via C-terminal oxidation. Methylmalonyl coenzyme A mutase and malate synthase are constitutive in this organism. The incorporation of 14CO2 into pyruvate accumulated during propionate utilization suggests that propionate is metabolized via the methyl-malonyl-succinate pathway. These results were further substantiated by radiorespirometric studies with propionate-1-14C, -2-14C, and -3-14C as substrate. Propane -2-14C was shown, by unlabeled competitor experiments, to be oxidized to acetone; acetone and isopropanol are oxidized in this organism to acetol. Cleavage of acetol to acetate and CO2 would yield the inducer for the isocitrate lyase present in propane-grown cells. PMID:5802607

  19. State Heating Oil & Propane Program. Final report 1997/98 heating season

    SciTech Connect

    Hunton, G.

    1998-06-01

    The following is a summary report of the New Hampshire Governor`s Office of Energy and Community Services (ECS) participation in the State Heating Oil and Propane Program (SHOPP) for the 1997/98 heating season. SHOPP is a cooperative effort, linking energy offices in East Coast and Midwest states, with the Department of Energy (DOE), Energy Information Administration (EIA) for the purpose of collecting retail price data for heating oil and propane. The program is funded by the participating state with a matching grant from DOE. SHOPP was initiated in response to congressional inquires into supply difficulties and price spikes of heating oil and propane associated with the winter of 1989/90. This is important to New Hampshire because heating oil controls over 55% of the residential heating market statewide. Propane controls 10% of the heating market statewide and is widely used for water heating and cooking in areas of the state where natural gas is not available. Lower installation cost, convenience, lower operating costs compared to electricity, and its perception as a clean heating fuel have all worked to increase the popularity of propane in New Hampshire and should continue to do so in the future. Any disruption in supply of these heating fuels to New Hampshire could cause prices to skyrocket and leave many residents in the cold.

  20. Epoxidation of Short-Chain Alkenes by Resting-Cell Suspensions of Propane-Grown Bacteria

    PubMed Central

    Hou, Ching T.; Patel, Ramesh; Laskin, Allen I.; Barnabe, Nancy; Barist, Irene

    1983-01-01

    Sixteen new cultures of propane-utilizing bacteria were isolated from lake water from Warinanco Park, Linden, N.J. and from lake and soil samples from Bayway Refinery, Linden, N.J. In addition, 19 known cultures obtained from culture collections were also found to be able to grow on propane as the sole carbon and energy source. In addition to their ability to oxidize n-alkanes, resting-cell suspensions of both new cultures and known cultures grown on propane oxidize short-chain alkenes to their corresponding 1,2-epoxides. Among the substrate alkenes, propylene was oxidized at the highest rate. In contrast to the case with methylotrophic bacteria, the product epoxides are further metabolized. Propane and other gaseous n-alkanes inhibit the epoxidation of propylene. The optimum conditions for in vivo epoxidation are described. Results from inhibition studies indicate that a propane monooxygenase system catalyzes both the epoxidation and hydroxylation reactions. Experiments with cell-free extracts show that both hydroxylation and epoxidation activities are located in the soluble fraction obtained after 80,000 × g centrifugation. PMID:16346338

  1. Heteroepitaxially grown zeolitic imidazolate framework membranes with unprecedented propylene/propane separation performances.

    PubMed

    Kwon, Hyuk Taek; Jeong, Hae-Kwon; Lee, Albert S; An, He Seong; Lee, Jong Suk

    2015-09-30

    Propylene/propane separation is one of the most challenging separations, currently achieved by energy-intensive cryogenic distillation. Despite the great potential for energy-efficient membrane-based separations, no commercial membranes are currently available due to the limitations of current polymeric materials. Zeolitic imidazolate framework, ZIF-8, with the effective aperture size of ∼4.0 Å, has been shown to be very promising for propylene/propane separation. Despite the extensive research on ZIF-8 membranes, only a few reported ZIF-8 membranes have displayed good propylene/propane separation performances presumably due to the challenges of controlling the microstructures of polycrystalline membranes. Here we report the first well-intergrown membranes of ZIF-67 (Co-substituted ZIF-8) by heteroepitaxially growing ZIF-67 on ZIF-8 seed layers. The ZIF-67 membranes exhibited impressively high propylene/propane separation capabilities. Furthermore, when a tertiary growth of ZIF-8 layers was applied to heteroepitaxially grown ZIF-67 membranes, the membranes exhibited unprecedentedly high propylene/propane separation factors of ∼200 possibly due to enhanced grain boundary structure.

  2. No. 2 heating oil/propane program 1994--1995. Final report

    SciTech Connect

    McBrien, J.

    1995-05-01

    During the 1994--95 heating season, the Massachusetts Division of Energy Resources (DOER) participated in a joint data collection program between several state energy offices and the federal Department of Energy`s (DOE) Energy Information Administration (EIA). The purpose of the program was to collect and monitor retail and wholesale heating oil and propane prices and inventories from October 1994 through March 1995. This program augmented the existing Massachusetts data collection system and served several important functions. The information helped the federal and state governments respond to consumer, congressional and media inquiries regarding No. 2 oil and propane. The information also provided policy decision-makers with timely, accurate and consistent data to monitor current heating oil and propane markets and develop appropriate state responses when necessary. In addition, the communication network between states and the DOE was strengthened through this program. This final report begins with an overview of the unique events that had an impact on the petroleum markets prior to and during the reporting period. Next, the report summarizes the results from residential heating oil and propane price surveys conducted by DOER over the 1994--95 heating season. The report also incorporates the wholesale heating oil and propane prices and inventories collected by EIA and distributed to the states. Finally, the report outlines DOER`s use of the data.

  3. Acetylene fermentation: An Earth-based analog of biological carbon cycling on Titan

    NASA Astrophysics Data System (ADS)

    Miller, L. G.; Baesman, S. M.; Hoeft, S. E.; Kirshtein, J.; Wolf, K.; Voytek, M. A.; Oremland, R. S.

    2009-12-01

    Acetylene (C2H2) is present in part per million quantities in the atmosphere of Titan; conceivably as an intermediate product of methane photolysis. Currently, Earth’s atmosphere contains only trace amounts of C2H2 (~40 pptv), however higher concentrations likely prevailed during the Hadean and early Archean eons (4.5 - 3.5 Ga). We isolated C2H2-fermenting microbes from various aquatic and sedimentary environments. Acetylene fermentation proceeds via acetylene hydratase (AH) through acetaldehyde, which dismutates to ethanol and acetate, and if oxidants are present (e.g., sulfate) eventually to CO2. Thus, the remnants of a C2H2 cycle exists today on Earth but may also occur on Titan and/or Enceladus, both being planetary bodies hypothesized to have liquid water underlying their frozen surfaces. We developed a molecular method for AH by designing PCR primers to target the functional gene in Pelobacter acetylenicus. We used this method to scan new environments for the presence of AH and we employed DNA sequencing of the 16S rRNA gene in order to positively identify pelobacters in environmental samples. Acetylene fermentation was documented in five diverse salt-, fresh-, and ground-water sites. Pelobacter was identified as the genus responsible for acetylene fermentation in some, but not all, of these sites. Successful probing for AH preceded the discovery of acetylene consumption in a contaminated groundwater site, demonstrating the utility of functional gene probing. A pure culture of a C2H2-fermenting pelobacter was obtained from an intertidal mudflat. We also obtained an enrichment culture (co-cultured with a sulfate reducer) from freshwater lake sediments, but neither was pelobacter nor AH detected in this sample, suggesting that an alternative pathway may be involved here. Slurry experiments using these lake sediments either with or without added C2H2 or sulfate showed that sulfate reduction and acetylene fermentation were independent processes. In general, the

  4. Enthalpies and entropies of vaporization of propan-2-ol-2-methylpropan-1-ol solutions

    NASA Astrophysics Data System (ADS)

    Baev, A. A.; Baev, A. K.

    2014-03-01

    P-T-x dependences are measured for the solutions of a propan-2-ol-2-methylpropan-1-ol binary system and the enthalpies and entropies of vaporization are determined. Dimerization in propan-2-ol and 2-methylpropan-1-ol is rationalized and the contribution from energy introduced by isostructural methyl groups to the enthalpy of vaporization is determined. Structural and energy analyses of solutions with networks of specific interactions are performed. The formation of heterodimers in solutions and vapors with reduced hydrogen bond energies and specific interactions with the 2 s 2(C) unshared electron pairs of the carbon atoms of terminal methyl groups in ethyl and propyl fragments of propan-2-ol and 2-methylpropan-1-ol, respectively, is substantiated. The hydrogen bond energy of heterodimers is estimated.

  5. Concentration of mechanical pulp mill effluents and NaCl solutions through propane hydrate formation

    SciTech Connect

    Ngan, Y.T.; Englezos, P.

    1996-06-01

    In this work, recovery of water from mechanical pulp mill effluents and 2.5 wt% NaCl solutions through propane hydrate formation was investigated. A new apparatus in which hydrate nucleation, growth, separation, and melting occur in one vessel was designed and built. The emphasis of the work was on crystal separation. The average reduction in the salt content of the recovered water from the NaCl solutions was found to be 31%. Displacement with propane could increase the amount of recovered water at the same purity level. Further improvement in the purity could be accomplished with washing with water. The results with the effluents showed that the total organic carbon and the salt content of the recovered water were lower by 23 and 26%, respectively, from the levels in the effluent. Improved separation could be achieved by displacement with liquid propane.

  6. Explosive-driven shock wave and vortex ring interaction with a propane flame

    NASA Astrophysics Data System (ADS)

    Giannuzzi, P. M.; Hargather, M. J.; Doig, G. C.

    2016-11-01

    Experiments were performed to analyze the interaction of an explosively driven shock wave and a propane flame. A 30 g explosive charge was detonated at one end of a 3-m-long, 0.6-m-diameter shock tube to produce a shock wave which propagated into the atmosphere. A propane flame source was positioned at various locations outside of the shock tube to investigate the effect of different strength shock waves. High-speed retroreflective shadowgraph imaging visualized the shock wave motion and flame response, while a synchronized color camera imaged the flame directly. The explosively driven shock tube was shown to produce a repeatable shock wave and vortex ring. Digital streak images show the shock wave and vortex ring propagation and expansion. The shadowgrams show that the shock wave extinguishes the propane flame by pushing it off of the fuel source. Even a weak shock wave was found to be capable of extinguishing the flame.

  7. Design and Operation of the Synthesis Gas Generator System for Reformed Propane and Glycerin Combustion

    NASA Astrophysics Data System (ADS)

    Pickett, Derek Kyle

    Due to an increased interest in sustainable energy, biodiesel has become much more widely used in the last several years. Glycerin, one major waste component in biodiesel production, can be converted into a hydrogen rich synthesis gas to be used in an engine generator to recover energy from the biodiesel production process. This thesis contains information detailing the production, testing, and analysis of a unique synthesis generator rig at the University of Kansas. Chapter 2 gives a complete background of all major components, as well as how they are operated. In addition to component descriptions, methods for operating the system on pure propane, reformed propane, reformed glycerin along with the methodology of data acquisition is described. This chapter will serve as a complete operating manual for future students to continue research on the project. Chapter 3 details the literature review that was completed to better understand fuel reforming of propane and glycerin. This chapter also describes the numerical model produced to estimate the species produced during reformation activities. The model was applied to propane reformation in a proof of concept and calibration test before moving to glycerin reformation and its subsequent combustion. Chapter 4 first describes the efforts to apply the numerical model to glycerin using the calibration tools from propane reformation. It then discusses catalytic material preparation and glycerin reformation tests. Gas chromatography analysis of the reformer effluent was completed to compare to theoretical values from the numerical model. Finally, combustion of reformed glycerin was completed for power generation. Tests were completed to compare emissions from syngas combustion and propane combustion.

  8. Toxicological investigation of liquid petroleum gas explosion: human model for propane/ethyl mercaptan exposures.

    PubMed

    Lowry, W T; Gamse, B; Armstrong, A T; Corn, J M; Juarez, L; McDowell, J L; Owens, R

    1991-03-01

    Four individuals died as the result of a propane explosion. As with many propane explosions, the question was raised as to the adequacy of the product's odorization after the autopsy studies had been conducted. In most cases, this question leads to litigation. Ethyl mercaptan is a widely used odorant for propane and was used in this instance. Three of the four victims had blood available at autopsy for study. Quantitative analyses of the victims' blood, obtained during autopsy, were performed using gas chromatography/mass spectrometry, without subjecting the samples to hydrolysis. These analyses determined the relative amounts of propane and ethyl mercaptan in the blood to be 90, 63, and 175 mL/m3 headspace, and 0.36, 0.34, and 0.77 microgram/L blood, respectively. Since mercaptans have been reported in human blood as products of metabolism, modeling studies were conducted to establish the validity of the autopsy data and to develop an autopsy toxicology protocol for investigating explosion deaths. When subjects were not exposed to an atmosphere containing ethyl mercaptan, dimethylsulfide was the only mercaptan detectable in their blood without severe hydrolysis prior to analysis. Metabolic ethyl mercaptan is sufficiently bound to be undetectable by the methods used without hydrolysis. Human subjects were exposed to a flammable mixture of air and propane odorized with ethyl mercaptan. The analyses of the blood from these subjects produced results which were comparable with those for the explosion victims, establishing that the question of odorant adequacy can be addressed at the autopsy of propane explosion victims. It is extremely important that the pathologist and toxicologist investigating gas explosion deaths recognize the valuable evidence existing in the victim's blood.

  9. An improved processible acetylene-terminated polyimide for composites

    NASA Technical Reports Server (NTRS)

    Landis, A. L.; Naselow, A. B.

    1985-01-01

    The newest member of a family of thermosetting acetylene-substituted polyimide oligomers is HR600P. This oligomer is the isoimide version of the oligomer known as HR600P and Thermid 600. Although both types of material yield the same heat resistant end products after cure, HR600P has much superior processing characteristics. This attributed to its lower melting temperature (160 + or - 10 C, 320 + or - 20 F) in contrast to 202 C (396 F) for Thermid MC-600, its longer gel time at its processing temperature (16 to 30 minutes bvs 3 minutes), and its excellent solubility in low boiling solvents such as tetrahydrofuran, glymes, or 4:1 methyl ethyl ketone/toluene mixtures. These advantages provide more acceptable coating and impregnation procedures, allow for more complete removal at lower temperatures, provide a longer pot life or working time, and allow composite structure fabrication in conventional autoclaves used for epoxy composite curing. The excellent processing characteristics of HR600P allow its use in large area laminated structures, structural composites, and molding compositions.

  10. Acetylene-chromene terminated resins as high temperature thermosets

    NASA Technical Reports Server (NTRS)

    Godschalx, J. P.; Inbasekaran, M. N.; Bartos, B. R.; Scheck, D. M.; Laman, S. A.

    1990-01-01

    A novel phase transfer catalyzed process for the preparation of propargyl ethers has been developed. The propargyl ethers serve as precursors to a new class of thermosetting resins called acetylene-chromene terminated (ACT) resins. Heat treatment of a solution of propargyl ethers with various catalysts, followed by removal of solvent leads to the ACT resins via partial conversion of the propargyl ether groups to chromenes. This process reduces the energy content of the resin systems and reduces the amount of shrinkage found during cure. Due to the presence of the solvent the process is safe and gives rise to low viscosity products suitable for resin transfer molding and filament winding type applications. Due to the high glass transition temperature, high modulus, and low moisture uptake the cured resins display better than 232 C/wet performance. The thermal stability of the ACT resins in air at 204 C is superior to that of conventional bismaleimide resins. The resins also display excellent electrical properties.

  11. 41 CFR 102-74.280 - Are privately owned vehicles converted for propane carburetion permitted in underground parking...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... vehicles converted for propane carburetion permitted in underground parking facilities? 102-74.280 Section... underground parking facilities? Federal agencies must not permit privately owned vehicles converted for propane carburetion to enter underground parking facilities unless the owner provides to the...

  12. 41 CFR 102-74.280 - Are privately owned vehicles converted for propane carburetion permitted in underground parking...

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... vehicles converted for propane carburetion permitted in underground parking facilities? 102-74.280 Section... underground parking facilities? Federal agencies must not permit privately owned vehicles converted for propane carburetion to enter underground parking facilities unless the owner provides to the...

  13. Ionization of large homogeneous and heterogeneous clusters generated in acetylene-Ar expansions: Cluster ion polymerization

    SciTech Connect

    Kocisek, J.; Lengyel, J.; Farnik, M.

    2013-03-28

    Pure acetylene and mixed Ar-acetylene clusters are formed in supersonic expansions of acetylene/argon mixtures and analysed using reflectron time-of-flight mass spectrometer with variable electron energy ionization source. Acetylene clusters composed of more than a hundred acetylene molecules are generated at the acetylene concentration of Almost-Equal-To 8%, while mixed species are produced at low concentrations ( Almost-Equal-To 0.7%). The electron energy dependence of the mass spectra revealed the ionization process mechanisms in clusters. The ionization above the threshold for acetylene molecule of 11.5 eV results in the main ionic fragment progression (C{sub 2}H{sub 2}){sub n}{sup +}. At the electron energies Greater-Than-Or-Slanted-Equal-To 21.5 eV above the CH+CH{sup +} dissociative ionization limit of acetylene the fragment ions nominally labelled as (C{sub 2}H{sub 2}){sub n}CH{sup +}, n Greater-Than-Or-Slanted-Equal-To 2, are observed. For n Less-Than-Or-Slanted-Equal-To 7 these fragments correspond to covalently bound ionic structures as suggested by the observed strong dehydrogenation [(C{sub 2}H{sub 2}){sub n}-k Multiplication-Sign H]{sup +} and [(C{sub 2}H{sub 2}){sub n}CH -k Multiplication-Sign H]{sup +}. The dehydrogenation is significantly reduced in the mixed clusters where evaporation of Ar instead of hydrogen can stabilize the nascent molecular ion. The C{sub 3}H{sub 3}{sup +} ion was previously assigned to originate from the benzene molecular ion; however, the low appearance energy of Almost-Equal-To 13.7 eV indicates that a less rigid covalently bound structure of C{sub 6}H{sub 6}{sup +} ion must also be formed upon the acetylene cluster electron ionization. The appearance energy of Ar{sub n}(C{sub 2}H{sub 2}){sup +} fragments above Almost-Equal-To 15.1 eV indicates that the argon ionization is the first step in the fragment ion production, and the appearance energy of Ar{sub n{>=}2}(C{sub 2}H{sub 2}){sub m{>=}2}{sup +} at Almost-Equal-To 13

  14. Acetylene Fermentation: Relevance to Primordial Biogeochemistry and the Search for Life in the Outer Solar System

    NASA Astrophysics Data System (ADS)

    Oremland, R. S.; Baesman, S. M.; Miller, L. G.

    2013-12-01

    Acetylene is a highly reactive component of planet(oid)s with anoxic, methane-rich atmospheres, such as Jupiter, Saturn, Titan, and perhaps the primordial Earth. Included in this group is Enceladus, although it is not clear if the acetylene detected within its jets by Cassini was formed by photolysis of methane, from thermo-catalysis of organic matter in the orb's interior, or a fragmentation artifact of the mass spectrum of a larger hydrocarbon. Acetylene inhibits many microbial processes (e.g., methanogenesis, methane oxidation, hydrogen metabolism, denitrification) yet a number of anaerobes can use it as a carbon and energy source to support growth. The best studied is Pelobacter acetylenicus, which carries out a two-step reaction involving the enzymes acetylene hydratase and acetaldehyde dismutase. The former, a low potential W-containing enzyme, forms acetaldehyde while the latter produces ethanol and acetate. Metabolism of acetylene by mixed microbial communities (sediments and/or enrichment cultures) produces these intermediates, and when coupled with sulfate-reduction or methanogenesis respectively forms CO2 or an equal mixtures of CO2 plus CH4. It is not inconceivable that such an anaerobic, microbial food chain could exist in the waters beneath the ice cap of Enceladus, Titan, or even in the mesothermal atmospheric regions of the gas giants. Detection of the identified intermediate products of acetylene fermentation, namely acetaldehyde, ethanol, acetate and formate in the atmospheres of these planet(oid)s would constitute evidence for a microbial life signature. This evidence would be strongly reinforced if a stable carbon isotope fractionation was identified as well, whereby the products of acetylene fermentation were enriched in 12C relative to 13C (i.e., had a lighter δ13C signal) when compared to that of the starting acetylene. The most practical target to test this hypothesis would be Enceladus (if the detected acetylene is shown to be a real

  15. Acetylene fuels reductive dechlorination of TCE by Dehalococcoides/Pelobacter-containing microbial consortia

    NASA Astrophysics Data System (ADS)

    Oremland, R. S.; Mao, X.; Mahandra, C.; Baesman, S. M.; Gushgari, S.; Alvarez-Cohen, L.; Liu, T.

    2015-12-01

    Groundwater contamination by trichloroethene (TCE) poses a threat to health and leads to the generation of vinyl chloride (VC), a carcinogen. Dehalococcoides mccartyi is the only bacterium that can completely dechlorinate TCE to ethene (C2H4). Acetylene (C2H2) occurs in TCE-contaminated sites as a consequence of chemical degradation of TCE. Yet acetylene inhibits a variety of microbial processes including methanogesis and reductive dechlorination. Pelobacter acetylenicus and related species can metabolize acetylene via acetylene hydratase and acetaldehyde dismutatse thereby generating acetate and H2 as endproducts, which could serve as electron donor and carbon source for growth of D. mccartyi. We found that 1mM acetylene (aqueous) inhibits growth of D. mccartyi strain 195 on 0.3 mM TCE, but that the inhibition was removed after 12 days with the addition of an acetylene-utilizing isolate from San Francisco Bay, Pelobacter strain SFB93. TCE did not inhibit the growth of this Pelobacter at the concentrations tested (0.1-0.5 mM) and TCE was not consumed by strain SFB93. Co-cultures of strain 195 with strain SFB93 at 5% inoculation were established in 120 mL serum bottles containing 40 mL defined medium. TCE was supplied at a liquid concentration of 0.1 mM, with 0.1 mM acetylene and N2/CO2 (90:10 v/v) headspace at 34 °C. Co-cultures were subsequently transferred (5% vol/vol inoculation) to generate subcultures after 20 μmol TCE was reduced to VC and 36 μmol acetylene was depleted. Aqueous H2 ranged from 114 to 217 nM during TCE-dechlorination, and the cell yield of strain 195 was 3.7 ±0.3 × 107 cells μmol-1 Cl- released. In a D. mccartyi-containing enrichment culture (ANAS) under the same conditions as above, it was found that inhibition of dechlorination by acetylene was reversed after 19 days by adding SFB93. Thus we showed that a co-culture of Pelobacter SFB93 and D. mccartyi 195 could be maintained with C2H2 as the electron donor and carbon source while TCE

  16. Ethylene capacity tops 77 million mty

    SciTech Connect

    Rhodes, A.K.; Knott, D.

    1995-04-17

    World ethylene production capacity is 77.8 million metric tons/year (mty). This total represents an increase of more than 6 million mty, or almost 9%, over last year`s survey. The biggest reason for the large change is more information about plants in the CIS. Also responsible for the increase in capacity is the start-up of several large ethylene plants during the past year. The paper discusses construction of ethylene plants, feedstocks, prices, new capacity, price outlook, and problems in Europe`s ethylene market.

  17. [Photodissociation of Acetylene and Acetone using Step-Scan Time-Resolved FTIR Emission Spectroscopy

    NASA Technical Reports Server (NTRS)

    McLaren, Ian A.; Wrobel, Jacek D.

    1997-01-01

    The photodissociation of acetylene and acetone was investigated as a function of added quenching gas pressures using step-scan time-resolved FTIR emission spectroscopy. Its main components consist of Bruker IFS88, step-scan Fourier Transform Infrared (FTIR) spectrometer coupled to a flow cell equipped with Welsh collection optics. Vibrationally excited C2H radicals were produced from the photodissociation of acetylene in the unfocused experiments. The infrared (IR) emission from these excited C2H radicals was investigated as a function of added argon pressure. Argon quenching rate constants for all C2H emission bands are of the order of 10(exp -13)cc/molecule.sec. Quenching of these radicals by acetylene is efficient, with a rate constant in the range of 10(exp -11) cc/molecule.sec. The relative intensity of the different C2H emission bands did not change with the increasing argon or acetylene pressure. However, the overall IR emission intensity decreased, for example, by more than 50% when the argon partial pressure was raised from 0.2 to 2 Torr at fixed precursor pressure of 160mTorr. These observations provide evidence for the formation of a metastable C2H2 species, which are collisionally quenched by argon or acetylene. Problems encountered in the course of the experimental work are also described.

  18. Acetylene reaction with the Si(111) surface: A semiempirical quantum chemical study

    NASA Astrophysics Data System (ADS)

    Weiner, B.; Carmer, C. S.; Frenklach, M.

    1991-01-01

    The interaction between the acetylene molecule and the Si(111) surface was modeled using the geometry optimization pathway of the Zerner intermediate neglect of differential overlap semiempirical quantum chemical program. The surface was represented by a 49-atom cluster containing four layers of silicon atoms. To determine the effect of the interaction upon the silicon surface, 12 central atoms from the top two layers were allowed to move to stable positions. The geometry of the silicon surface was initially optimized without acetylene, resulting in a significant rearrangement of the mobile atoms. Nine separate calculations were then performed, differing in the initial position and orientation of the acetylene molecule above the surface. The geometry of the resulting surface structures was found to be highly dependent upon the initial placement and orientation of the acetylene. In each case, the acetylene was found to react with the silicon surface by the formation of Si-C bonds. An analysis of the Wiberg bond indices revealed that the initial triple bond between carbon atoms was reduced to approximately a single bond, the exact bond order varying slightly from case to case. It was also found that Si-Si bonds surrounding the reaction site were weakened, and in some cases broken, due to the strain induced by the Si-C bond formation. The degree to which the surfaces were rearranged was found to correlate with the final energies, indicating that the most distorted surfaces were the most energetically favorable.

  19. Adsorption of binary mixtures of ethane and acetylene on activated carbon

    SciTech Connect

    Lee, T.V.; Huang, J.C.; Rothstein, D.; Madey, R.

    1984-01-01

    Dynamic measurement of the adsorption of binary mixtures of ethane and acetylene (and also of each gas alone) in a helium carrier gas were made on an (Columbia 4LXC 12/28) activated carbon adsorber bed at 25/sup 0/C. The adsorption capacities of the activated carbon for the pure gases and for each component in the mixtures are extracted from the transmission curves by the use of a mass balance equation. Transmission is the ratio of the concentration at the outlet of the adsorber bed to that at the inlet. The adsorption isotherms for pure ethane and acetylene can be presented by a modified Langmuir isotherm known as the Chakravarti-Dhar isotherm at gas concentrations up to at least 4.2 X 19/sup -7/ mol/cm/sup 3/ (viz., 7.8 mmHg). The gas-adsorbate equilibrium composition and the adsorption capacity of each component in the binary mixture of ethane and acetylene are estimated from the corresponding single-component isotherms by applying ideal adsorbed solution theory (IAST). The fact that the estimated values of the adsorption capacities and the gas-adsorbate equilibrium compositions are in good agreement with those extracted from the measurements for the binary mixtures of ethane and acetylene confirms that the ethane-acetylene system forms an ideal adsorbed phase on activated carbon at a pressure of about 7.3 mmHg and a temperature of 25/sup 0/C. 20 references, 4 figures, 4 tables.

  20. Time dependence of ethylene decomposition and byproducts formation in a continuous flow dielectric-packed plasma reactor.

    PubMed

    Gandhi, M Sanjeeva; Ananth, Antony; Mok, Young Sun; Song, Jun-Ik; Park, Kyu-Hyun

    2013-04-01

    This work investigated the decomposition of ethylene in a continuous flow dielectric-packed bed plasma reactor filled with various packing materials at atmospheric pressure and room temperature. When compared to the case without any packing material, the reactor filled with packing materials remarkably facilitated the plasma-induced decomposition of ethylene in the order of α-alumina>silica>zirconia>glass wool (GW). Under identical condition, the increase in the decomposition efficiency (DE) with increasing the specific energy input was more rapid in the plasma reactor filled with the packing materials than in the blank plasma reactor. In the early stage, almost complete decomposition of ethylene was observed with the α-alumina, but after a certain period of time, the DE decreased with time. Unlike the α-alumina, the other packing materials examined did not show any significant deterioration in the decomposition over time during 10-h operation. After the regeneration of the used packing materials by using the plasma in the presence of oxygen, the original decomposition performance was nearly recovered. The decrease in the BET surface area due to the formation of polymer deposits was observed in the used α-alumina and silica; however the surface area was almost regained by the regeneration. While no other byproducts except carbon oxides and N2O were detected with the α-alumina and silica, methane, acetylene, formaldehyde and N2O were identified in the effluent gas with the zirconia and GW packing materials.

  1. Ethylene Regulates Levels of Ethylene Receptor/CTR1 Signaling Complexes in Arabidopsis thaliana

    DOE PAGES

    Shakeel, Samina N.; Gao, Zhiyong; Amir, Madiha; ...

    2015-03-26

    The plant hormone ethylene is perceived by a five-member family of receptors in Arabidopsis thaliana. The receptors function in conjunction with the Raf-like kinase CTR1 to negatively regulate ethylene signal transduction. CTR1 interacts with multiple members of the receptor family based on co-purification analysis, interacting more strongly with receptors containing a receiver domain. Levels of membrane-associated CTR1 vary in response to ethylene, doing so in a post-transcriptional manner that correlates with ethylene-mediated changes in levels of the ethylene receptors ERS1, ERS2, EIN4, and ETR2. Interactions between CTR1 and the receptor ETR1 protect ETR1 from ethylene-induced turnover. Kinetic and dose-response analysesmore » support a model in which two opposing factors control levels of the ethylene receptor/CTR1 complexes. Ethylene stimulates the production of new complexes largely through transcriptional induction of the receptors. However, ethylene also induces turnover of receptors, such that levels of ethylene receptor/CTR1 complexes decrease at higher ethylene concentrations. Lastly, we discuss implications of this model for ethylene signaling.« less

  2. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase

    SciTech Connect

    Carlin, DA; Bertolani, SJ; Siegel, JB

    2015-01-01

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  3. Ethylene and pollination decrease transcript abundance of an ethylene receptor gene in Dendrobium petals.

    PubMed

    Thongkum, Monthathip; Burns, Parichart; Bhunchoth, Anjana; Warin, Nuchnard; Chatchawankanphanich, Orawan; van Doorn, Wouter G

    2015-03-15

    We studied the expression of a gene encoding an ethylene receptor, called Ethylene Response Sensor 1 (Den-ERS1), in the petals of Dendrobium orchid flowers. Transcripts accumulated during the young floral bud stage and declined by the time the flowers had been open for several days. Pollination or exposure to exogenous ethylene resulted in earlier flower senescence, an increase in ethylene production and a lower Den-ERS1 transcript abundance. Treatment with 1-methylcyclopropene (1-MCP), an inhibitor of the ethylene receptor, decreased ethylene production and resulted in high transcript abundance. The literature indicates two kinds of ethylene receptor genes with regard to the effects of ethylene. One group shows ethylene-induced down-regulated transcription, while the other has ethylene-induced up-regulation. The present gene is an example of the first group. The 5' flanking region showed binding sites for Myb and myb-like, homeodomain, MADS domain, NAC, TCP, bHLH and EIN3-like transcription factors. The binding site for the EIN3-like factor might explain the ethylene effect on transcription. A few other transcription factors (RAV1 and NAC) seem also related to ethylene effects.

  4. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase.

    PubMed

    Carlin, D A; Bertolani, S J; Siegel, J B

    2015-02-11

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  5. Ethylene Regulates Levels of Ethylene Receptor/CTR1 Signaling Complexes in Arabidopsis thaliana.

    PubMed

    Shakeel, Samina N; Gao, Zhiyong; Amir, Madiha; Chen, Yi-Feng; Rai, Muneeza Iqbal; Haq, Noor Ul; Schaller, G Eric

    2015-05-08

    The plant hormone ethylene is perceived by a five-member family of receptors in Arabidopsis thaliana. The receptors function in conjunction with the Raf-like kinase CTR1 to negatively regulate ethylene signal transduction. CTR1 interacts with multiple members of the receptor family based on co-purification analysis, interacting more strongly with receptors containing a receiver domain. Levels of membrane-associated CTR1 vary in response to ethylene, doing so in a post-transcriptional manner that correlates with ethylene-mediated changes in levels of the ethylene receptors ERS1, ERS2, EIN4, and ETR2. Interactions between CTR1 and the receptor ETR1 protect ETR1 from ethylene-induced turnover. Kinetic and dose-response analyses support a model in which two opposing factors control levels of the ethylene receptor/CTR1 complexes. Ethylene stimulates the production of new complexes largely through transcriptional induction of the receptors. However, ethylene also induces turnover of receptors, such that levels of ethylene receptor/CTR1 complexes decrease at higher ethylene concentrations. Implications of this model for ethylene signaling are discussed.

  6. Poly(ethylene oxide) functionalization

    DOEpatents

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  7. Thermodynamic analysis of hydrocarbon refrigerants-based ethylene BOG re-liquefaction system

    NASA Astrophysics Data System (ADS)

    Beladjine, Boumedienne M.; Ouadha, Ahmed; Addad, Yacine

    2016-09-01

    The present study aims to make a thermodynamic analysis of an ethylene cascade re-liquefaction system that consists of the following two subsystems: a liquefaction cycle using ethylene as the working fluid and a refrigeration cycle operating with a hydrocarbon refrigerant. The hydrocarbon refrigerants considered are propane (R290), butane (R600), isobutane (R600a), and propylene (R1270). A computer program written in FORTRAN is developed to compute parameters for characteristic points of the cycles and the system's performance, which is determined and analyzed using numerical solutions for the refrigerant condensation temperature, temperature in tank, and temperature difference in the cascade condenser. Results show that R600a gives the best performance, followed by (in order) R600, R290, and R1270. Furthermore, it is found that an increase in tank temperature improves system performance but that an increase in refrigerant condensation temperature causes deterioration. In addition, it is found that running the system at a low temperature difference in the cascade condenser is advantageous.

  8. Gas Chromatographic Separation of an Acetylene Vinyl Fluoride-Difluoroethane Mixture on Triethylene Glycol and Silicone Oil,

    DTIC Science & Technology

    The purpose of the research was to study gas-chromatographic separation of impurities of acetylene and difluoroethane in vinyl fluoride obtained by...and difluoroethane . All the components are separated, and the criteria of separation of acetylene-vinyl fluoride and vinyl fluoride- difluoroethane

  9. Metabolism of Propane, n-Propylamine, and Propionate by Hydrocarbon-Utilizing Bacteria1

    PubMed Central

    Blevins, W. T.; Perry, J. J.

    1972-01-01

    Studies were conducted on the oxidation and assimilation of various three-carbon compounds by a gram-positive rod isolated from soil and designated strain R-22. This organism can utilize propane, propionate, or n-propylamine as sole source of carbon and energy. Respiration rates, enzyme assays, and 14CO2 incorporation experiments suggest that propane is metabolized via methyl ketone formation; propionate and n-propylamine are metabolized via the methylmalonyl-succinate pathway. Isocitrate lyase activity was found in cells grown on acetate and was not present in cells grown on propionate or n-propylamine. 14CO2 was incorporated into pyruvate when propionate and n-propylamine were oxidized in the presence of NaAsO2, but insignificant radioactivity was found in pyruvate produced during the oxidation of propane and acetone. The n-propylamine dissimilatory mechanism was inducible in strain R-22, and amine dehydrogenase activity was detected in cells grown on n-propylamine. Radiorespirometer and 14CO2 incorporation studies with several propane-utilizing organisms indicate that the methylmalonyl-succinate pathway is the predominant one for the metabolism of propionate. PMID:16559164

  10. Performance and emissions of a catalytic reactor with propane, diesel, and Jet A fuels

    NASA Technical Reports Server (NTRS)

    Anderson, D. N.

    1977-01-01

    Tests were made to determine the performance and emissions of a catalytic reactor operated with propane, No. 2 diesel, and Jet A fuels. A 12-cm diameter and 16-cm long catalytic reactor using a proprietary noble metal catalyst was operated at an inlet temperature of 800 K, a pressure of 300,000 Pa and reference velocities of 10 to 15 m/s. No significant differences between the performance of the three fuels were observed when 98.5 percent purity propane was used. The combustion efficiency for 99.8-percent purity propane tested later was significantly lower, however. The diesel fuel contained 135 ppm of bound nitrogen and consequently produced the highest NOx emissions of the three fuels. As much as 85 percent of the bound nitrogen was converted to NOx. Steady-state emissions goals based on half the most stringent proposed automotive standards were met when the reactor was operated at an adiabatic combustion temperature higher than 1350 K with all fuels except the 99.8-percent purity propane. With that fuel, a minimum temperature of 1480 K was required.

  11. Synthesis and characterization of energetic salts based on the new propan-2-ylidene methanetriamium cations

    NASA Astrophysics Data System (ADS)

    Zhang, Tao; Liu, Long; Li, Chunshan; Zhang, Yanqiang; Li, Zengxi; Zhang, Suojiang

    2014-06-01

    Development of new hypergolic ionic liquids is the key in replacing toxic N,N-dimethylhydrazine as green liquids propellants. Three salts based on the new propan-2-ylidene methanetriamium cations and dicyanamide anion were synthesized and characterized by 1H and 13C NMR, IR and Raman spectroscopy, elemental analysis, and TG/DTA. In addition, their crystal structures were determined by X-ray single crystal diffraction. N-(propan-2-ylidene) methanetriamium dicyanamide (1) crystallizes in the monoclinic space group P21/n, N,N‧-bi(propan-2-ylidene) methanetriamium dicyanamide (2) in triclinic P - 1, and N,N‧,N″-tri(propan-2-ylidene) methanetriamium dicyanamide (3) in monoclinic C2/c. With heats of formation (from 1.56 to 1.80 kJ g-1) and densities (from 1.19 to 1.31 g cm-3) in hand, the detonation pressure (P) and velocity (D), and specific impulse (Isp) values of salts were calculated as 8.94 GPa, 4989 m s-1 and 174.3 s (1), 7.91 GPa, 4815 m s-1 and 179.0 s (2), and 7.33 GPa, 4693 m s-1 and 180.6 s (3), respectively. Impact sensitivities of 1, 2 and 3 were measured to be no less than 40 J by hammer tests, which places these salts in the insensitive class. Moreover, the resulting salts are hypergolic with white fuming nitric acid and exhibit potential as bipropellants.

  12. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  13. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  14. 40 CFR 721.10360 - 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol mono...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...-(triethoxysilyl)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (generic). 721.10360... Substances § 721.10360 1-Substituted propane, 3-(triethoxysilyl)-, reaction products with polyethylene glycol...)-, reaction products with polyethylene glycol mono-(branched tridecyl) ether (PMN P-09-628) is subject...

  15. A Theoretical Study of the Methyl and Aldehyde Torsion FIR Spectra in Symmetric Propanal Isotopomers

    NASA Astrophysics Data System (ADS)

    Smeyers, Y. G.; Villa, M.; Uc, V. H.; Vivier-Bunge, A.

    2000-05-01

    This paper is an extension of the techniques developed by us [A. Vivier-Bunge, V. H. Uc, and Y. G. Smeyers, J. Chem. Phys. 109, 2279 (1998)] for standard propanal. In that paper the potential energy surface for the simultaneous methyl and asymmetric aldehydic torsions was calculated at RHF/MP2 level using the 6-311(3df,p) basis set for propanal. The fit of the energy values to symmetry-adapted functional forms was carried out by using the 28 energy values which retain the C3 dynamical symmetry of the methyl group in the optimization procedure. With this potential, as well as with the kinetic parameters and the electric dipole moment variations, the FIR frequencies and intensities for the methyl and aldehyde torsions of seven symmetric isotopomers of propanal were determined theoretically using two-dimensional calculations. The calculated spectra of propanal and three of its isotopomers were compared with the available experimental data. It is found that the calculations for the cis conformer satisfactorily reproduce the aldehyde and methyl torsion spectra and furnish also methyl torsionally excited progressions for the aldehyde torsion modes. The methyl torsion frequencies agree especially well whenever the methyl group is nondeuterated. The small deviations encountered for the deuterated compound are probably due to some mass effect, such as the zero-point vibrational energy correction, which is not taken into account in the present calculations. Finally, the influence of the deuteration on the intensities is discussed.

  16. Surface Termination of M1 Phase and Rational Design of Propane Ammoxidation Catalysts

    SciTech Connect

    Guliants, Vadim

    2015-02-16

    This final report describes major accomplishments in this research project which has demonstrated that the M1 phase is the only crystalline phase required for propane ammoxidation to acrylonitrile and that a surface monolayer terminating the ab planes of the M1 phase is responsible for their activity and selectivity in this reaction. Fundamental studies of the topmost surface chemistry and mechanism of propane ammoxidation over the Mo-V-(Te,Sb)-(Nb,Ta)-O M1 and M2 phases resulted in the development of quantitative understanding of the surface molecular structure – reactivity relationships for this unique catalytic system. These oxides possess unique catalytic properties among mixed metal oxides, because they selectively catalyze three alkane transformation reactions, namely propane ammoxidation to acrylonitrile, propane oxidation to acrylic acid and ethane oxidative dehydrogenation, all of considerable economic significance. Therefore, the larger goal of this research was to expand this catalysis to other alkanes of commercial interest, and more broadly, demonstrate successful approaches to rational design of improved catalysts that can be applied to other selective (amm)oxidation processes.

  17. RETENTION OF HALOCARBONS ON A HEXAFLUOROPROPYLENE EPOXIDE-MODIFIED GRAPHITIZED CARBON BLACK - IV. PROPANE- BASED COMPOUNDS

    EPA Science Inventory

    The retention characteristics of 25 propane-based bromofluorocarbon, chlorocarbon, chlorofluorocarbon, and fluorocarbon fluids have been studied as a function of temperature on a stationary phase consisting of a 5% (m/m) coating of a low-molecular-mass polymer of hexafluoropropyl...

  18. Analysis of U.S. Propane Markets Winter 1996-97, An

    EIA Publications

    1997-01-01

    This study constitutes an examination of propane supply, demand, and price developments and trends. The Energy Information Administration's approach focused on identifying the underlying reasons for the tight supply/demand balance in the fall of 1996, and on examining the potential for a recurrence of these events next year.

  19. Zinc-substituted ZIF-67 nanocrystals and polycrystalline membranes for propylene/propane separation.

    PubMed

    Wang, Chongqing; Yang, Fan; Sheng, Luqian; Yu, Jian; Yao, Kexin; Zhang, Lixiong; Pan, Yichang

    2016-10-18

    Continuous ZIF-67 polycrystalline membranes with effective propylene/propane separation performances were successfully fabricated through the incorporation of zinc ions into the ZIF-67 framework. The separation factor increases from 1.4 for the pure ZIF-67 membrane to 50.5 for the 90% zinc-substituted ZIF-67 membrane.

  20. 16 CFR Figure 7 to Part 1633 - Elements of Propane Flow Control for Each Burner

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 16 Commercial Practices 2 2013-01-01 2013-01-01 false Elements of Propane Flow Control for Each Burner 7 Figure 7 to Part 1633 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS SETS Pt. 1633, Fig. 7 Figure...

  1. 16 CFR Figure 7 to Part 1633 - Elements of Propane Flow Control for Each Burner

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 16 Commercial Practices 2 2011-01-01 2011-01-01 false Elements of Propane Flow Control for Each Burner 7 Figure 7 to Part 1633 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS SETS Pt.1633, Fig. 7 Figure...

  2. 16 CFR Figure 7 to Part 1633 - Elements of Propane Flow Control for Each Burner

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 16 Commercial Practices 2 2010-01-01 2010-01-01 false Elements of Propane Flow Control for Each Burner 7 Figure 7 to Part 1633 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS SETS Pt.1633, Fig. 7 Figure...

  3. 16 CFR Figure 7 to Part 1633 - Elements of Propane Flow Control for Each Burner

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 16 Commercial Practices 2 2014-01-01 2014-01-01 false Elements of Propane Flow Control for Each Burner 7 Figure 7 to Part 1633 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS SETS Pt. 1633, Fig. 7 Figure...

  4. 16 CFR Figure 7 to Part 1633 - Elements of Propane Flow Control for Each Burner

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 16 Commercial Practices 2 2012-01-01 2012-01-01 false Elements of Propane Flow Control for Each Burner 7 Figure 7 to Part 1633 Commercial Practices CONSUMER PRODUCT SAFETY COMMISSION FLAMMABLE FABRICS ACT REGULATIONS STANDARD FOR THE FLAMMABILITY (OPEN FLAME) OF MATTRESS SETS Pt.1633, Fig. 7 Figure...

  5. 40 CFR 1065.341 - CVS and batch sampler verification (propane check).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow-Related... from the piping configuration upstream of the flow meter adversely affect the flow measurement. (7... measurements and CVS flow rate measurements with the reference value. (c) Prepare for the propane check...

  6. 40 CFR 1065.341 - CVS, PFD, and batch sampler verification (propane check).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... AGENCY (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow... from the piping configuration upstream of the flow meter adversely affect the flow measurement. (7... measurements and CVS flow rate measurements with the reference value. (c) Prepare for the propane check...

  7. 40 CFR 1065.341 - CVS and batch sampler verification (propane check).

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... (CONTINUED) AIR POLLUTION CONTROLS ENGINE-TESTING PROCEDURES Calibrations and Verifications Flow-Related... from the piping configuration upstream of the flow meter adversely affect the flow measurement. (7... measurements and CVS flow rate measurements with the reference value. (c) Prepare for the propane check...

  8. THE HEAT CAPACITY OF FLUORINATED PROPANE AND BUTANE DERIVATIVES BY DIFFERENTIAL SCANNING CALORIMETRY

    EPA Science Inventory

    The paper gives results of the measurement (to 3% accuracy) of the constant-pressure liquid-phase heat capacities of 21 hydrogen-containing fluorinated propane and butane derivatives and one fluorinated ether (CF3OCF2H) with boiling points ranging from -34.6 to 76.7 C, using diff...

  9. Abiotic reductive dechlorination of chlorinated ethylenes by iron-bearing soil minerals. 1. Pyrite and magnetite.

    PubMed

    Lee, Woojin; Batchelor, Bill

    2002-12-01

    Abiotic reductive dechlorination of chlorinated ethylenes (tetrachloroethylene (PCE), trichloroethylene (TCE), cis-dichloroethylene (cis-DCE), and vinyl chloride (VC)) by pyrite and magnetite was characterized in a batch reactor system. Dechlorination kinetics was adequately described by a modified Langmuir-Hinshelwood model that includes the effect of a decreasing reductive capacity of soil mineral. The kinetic rate constant for the reductive dechlorination of target organics at reactive sites of soil minerals was in the range of 0.185 (+/- 0.023) to 1.71 (+/- 0.06) day(-1). The calculated specific reductive capacity of soil minerals for target organics was in the range of 0.33 (+/- 0.02) to 2.26 (+/- 0.06) microM/g and sorption coefficient was in the range of 0.181 (+/- 0.006) to 0.7 (+/- 0.022) mM(-1). Surface area-normalized pseudo-first-order initial rate constants for target organics by pyrite were found to be 23.5 to 40.3 times greater than those by magnetite. Target organics were mainly transformed to acetylene and small amount of chlorinated intermediates, which suggests that beta-elimination was the main dechlorination pathway. The dechlorination of VC followed a hydrogenolysis pathway to produce ethylene and ethane. The addition of Fe(II) increased the dechlorination rate of cis-DCE and VC in magnetite suspension by nearly a factor of 10. The results obtained in this research provide basic knowledge to better predict the fate of chlorinated ethylenes and to understand the potential of abiotic processes in natural attenuation.

  10. On the radiolysis of ethylene ices by energetic electrons and implications to the extraterrestrial hydrocarbon chemistry

    SciTech Connect

    Zhou, Li; Maity, Surajit; Abplanalp, Matt; Turner, Andrew; Kaiser, Ralf I.

    2014-07-20

    The chemical processing of ethylene ices (C{sub 2}H{sub 4}) by energetic electrons was investigated at 11 K to simulate the energy transfer processes and synthesis of new molecules induced by secondary electrons generated in the track of galactic cosmic ray particles. A combination of Fourier transform infrared spectrometry (solid state) and quadrupole mass spectrometry (gas phase) resulted in the identification of six hydrocarbon molecules: methane (CH{sub 4}), the C2 species acetylene (C{sub 2}H{sub 2}), ethane (C{sub 2}H{sub 6}), the ethyl radical (C{sub 2}H{sub 5}), and—for the very first time in ethylene irradiation experiments—the C4 hydrocarbons 1-butene (C{sub 4}H{sub 8}) and n-butane (C{sub 4}H{sub 10}). By tracing the temporal evolution of the newly formed molecules spectroscopically online and in situ, we were also able to fit the kinetic profiles with a system of coupled differential equations, eventually providing mechanistic information, reaction pathways, and rate constants on the radiolysis of ethylene ices and the inherent formation of smaller (C1) and more complex (C2, C4) hydrocarbons involving carbon-hydrogen bond ruptures, atomic hydrogen addition processes, and radical-radical recombination pathways. We also discuss the implications of these results on the hydrocarbon chemistry on Titan's surface and on ice-coated, methane-bearing interstellar grains as present in cold molecular clouds such as TMC-1.

  11. Quantum Dynamics of Vinylidene Photodetachment on an Accurate Global Acetylene-Vinylidene Potential Energy Surface.

    PubMed

    Guo, Lifen; Han, Huixian; Ma, Jianyi; Guo, Hua

    2015-08-06

    Vinylidene is a high-energy isomer of acetylene, and the rearrangement of bonds in the two species serves as a prototype for isomerization reactions. Here, a full-dimensional quantum mechanical study of the vinylidene vibration is carried out on a recently developed global acetylene-vinylidene potential energy surface by simulating the photodetachment dynamics of the vinylidene anion. Several low-lying vibrational levels of the anion were first determined on a new ab initio based potential energy surface, and their photoelectron spectra were obtained within the Condon approximation. The vibrational features of the vinylidene isomer are found to agree well with the experiment in both positions and intensities, validating the global acetylene-vinylidene potential energy surface.

  12. Examining the impact of acetylene on N-fixation and the active sediment microbial community

    PubMed Central

    Fulweiler, Robinson W.; Heiss, Elise M.; Rogener, Mary Kate; Newell, Silvia E.; LeCleir, Gary R.; Kortebein, Sarah M.; Wilhelm, Steven W.

    2015-01-01

    Here we examined the impact of a commonly employed method used to measure nitrogen fixation, the acetylene reduction assay (ARA), on a marine sediment community. Historically, the ARA technique has been broadly employed for its ease of use, in spite of numerous known artifacts. To gauge the severity of these effects in a natural environment, we employed high-throughput 16S rRNA gene sequencing to detect differences in acetylene-treated sediments vs. non-treated control sediments after a 7 h incubation. Within this short time period, significant differences were seen across all activity of microbes identified in the sediment, implying that the changes induced by acetylene occur quickly. The results have important implications for our understanding of marine nitrogen budgets. Moreover, because the ARA technique has been widely used in terrestrial and freshwater habitats, these results may be applicable to other ecosystems. PMID:26029177

  13. Developing synthesis techniques for zeolitic-imidazolate framework membranes for high resolution propylene/propane separation

    NASA Astrophysics Data System (ADS)

    Kwon, Hyuk Taek

    Propylene/propane separation is one of the most challenging separations, currently achieved by energy-intensive cryogenic distillation. Despite the great potentials for energy-efficient membrane-based propylene/propane separation processes, no commercial membranes are available due to the limitations (i.e., low selectivity) of current polymeric materials. Zeolitic imidazolate frameworks (ZIFs) are promising membrane materials primarily due to their well-defined ultra-micropores with controllable surface chemistry along with their relatively high thermal/chemical stabilities. In particular, ZIF-8 with the effective aperture size of ~ 4.0 A has been shown very promising for propylene/propane separation. Despite the extensive research on ZIF-8 membranes, only a few of ZIF-8 membranes have displayed good propylene/propane separation performances presumably due to the challenges of controlling the microstructures of polycrystalline membranes. Since the membrane microstructures are greatly influenced by processing techniques, it is critically important to develop new techniques. In this dissertation, three state-of-the-art ZIF membrane synthesis techniques are developed. The first is a one-step in-situ synthesis technique based on the concept of counter diffusion. The technique enabled us to obtain highly propylene selective ZIF-8 membranes in less than a couple of hours with exceptional mechanical strength. Most importantly, due to the nature of the counter-diffusion concept, the new method offered unique opportunities such as healing defective membranes (i.e., poorly-intergrown) as well as significantly reducing the consumption of costly ligands and organic solvents. The second is a microwave-assisted seeding technique. Using this new seeding technique, we were able to prepare seeded supports with a high packing density in a couple of minutes, which subsequently grown into highly propylene-selective ZIF-8 membranes with an average propylene/propane selectivity of ~40

  14. Methods and compositions to modulate ethylene sensitivity

    DOEpatents

    Stepanova, Anna N.; Ecker, Joseph R.

    2007-01-30

    The field of the invention relates to plants and plant genes, including both plant mutants and transgenic plants containing a gene that confers an ethylene insensitive phenotype. Also encompassed by the invention are methods of using the disclosed plant gene to confer an ethylene insensitive phenotype.

  15. 29 CFR 1910.1047 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 6 2012-07-01 2012-07-01 false Ethylene oxide. 1910.1047 Section 1910.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR (CONTINUED) OCCUPATIONAL SAFETY AND HEALTH STANDARDS (CONTINUED) Toxic and Hazardous Substances § 1910.1047 Ethylene oxide. (a) Scope and...

  16. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 7 2011-07-01 2011-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  17. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 8 2014-07-01 2014-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  18. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  19. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  20. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 7 2013-07-01 2013-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  1. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 8 2012-07-01 2012-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  2. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 29 Labor 7 2012-07-01 2012-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  3. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 29 Labor 8 2013-07-01 2013-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  4. 29 CFR 1926.1147 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 8 2011-07-01 2011-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical...

  5. 29 CFR 1915.1047 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 29 Labor 7 2014-07-01 2014-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this...

  6. Targeting Plant Ethylene Responses by Controlling Essential Protein-Protein Interactions in the Ethylene Pathway.

    PubMed

    Bisson, Melanie M A; Groth, Georg

    2015-08-01

    The gaseous plant hormone ethylene regulates many processes of high agronomic relevance throughout the life span of plants. A central element in ethylene signaling is the endoplasmic reticulum (ER)-localized membrane protein ethylene insensitive2 (EIN2). Recent studies indicate that in response to ethylene, the extra-membranous C-terminal end of EIN2 is proteolytically processed and translocated from the ER to the nucleus. Here, we report that the conserved nuclear localization signal (NLS) mediating nuclear import of the EIN2 C-terminus provides an important domain for complex formation with ethylene receptor ethylene response1 (ETR1). EIN2 lacking the NLS domain shows strongly reduced affinity for the receptor. Interaction of EIN2 and ETR1 is also blocked by a synthetic peptide of the NLS motif. The corresponding peptide substantially reduces ethylene responses in planta. Our results uncover a novel mechanism and type of inhibitor interfering with ethylene signal transduction and ethylene responses in plants. Disruption of essential protein-protein interactions in the ethylene signaling pathway as shown in our study for the EIN2-ETR1 complex has the potential to guide the development of innovative ethylene antagonists for modern agriculture and horticulture.

  7. Novel Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation

    SciTech Connect

    Sun, Pingping; Siddiqi, Georges; Vining, William C.; Chi, Miaofang; Bell, Alexis T.

    2011-10-28

    Catalysts for the dehydrogenation of light alkanes were prepared by dispersing Pt on the surface of a calcined hydrotalcite-like support containing indium, Mg(In)(Al)O. Upon reduction in H{sub 2} at temperatures above 673 K, bimetallic particles of PtIn are observed by TEM, which have an average diameter of 1 nm. Analysis of Pt LIII-edge extended X-ray absorption fine structure (EXAFS) data shows that the In content of the bimetallic particles increases with increasing bulk In/Pt ratio and reduction temperature. Pt LIII-edge X-ray absorption near edge structure (XANES) indicates that an increasing donation of electronic charge from In to Pt occurs with increasing In content in the PtIn particles. The activity and selectivity of the Pt/Mg(In)(Al)O catalysts for ethane and propane dehydrogenation reactions are strongly dependent on the bulk In/Pt ratio. For both reactants, maximum activity was achieved for a bulk In/Pt ratio of 0.48, and at this In/Pt ratio, the selectivity to alkene was nearly 100%. Coke deposition was observed after catalyst use for either ethane or propane dehydrogenation, and it was observed that the alloying of Pt with In greatly reduced the amount of coke deposited. Characterization of the deposit by Raman spectroscopy indicates that the coke is present as highly disordered graphite particles <30 nm in diameter. While the amount of coke deposited during ethane and propane dehydrogenation are comparable, the effects on activity are dependent on reactant composition. Coke deposition had no effect on ethane dehydrogenation activity, but caused a loss in propane dehydrogenation activity. This difference is attributed to the greater ease with which coke produced on the surface of PtIn nanoparticles migrates to the support during ethane dehydrogenation versus propane dehydrogenation.

  8. The interaction between soot and NO formation in a laminar axisymmetric coflow ethylene/air diffusion flame

    SciTech Connect

    Guo, Hongsheng; Smallwood, Gregory J.

    2007-04-15

    The interaction between soot and NO formation in a laminar axisymmetric coflow ethylene/air diffusion flame was investigated by numerical simulation. A detailed gas-phase reaction scheme and a simplified soot model were employed. The results show that the formation of NO has little effect on that of soot. However, the formation of soot in the flame significantly suppresses the formation of NO. The peak NO concentration and NO emission index are reduced by 28 and 46%, respectively, due to the formation of soot. The influence of soot on NO formation is caused by not only the radiation-induced thermal effect, but also the reaction-induced chemical effect. Relatively the thermal effect is more significant, causing 25 and 38% reduction, respectively, in peak NO concentration and NO emission index. The chemical effect is caused by the competition for acetylene (C{sub 2}H{sub 2}) between soot and NO formation. The formation of soot consumes acetylene in the flame and thus lowers the formation rate of radical CH. This reduces the reaction rate of CH + N{sub 2} = HCN + N, which is the rate-limiting step of the prompt NO formation route, the dominant route in the studied flame. (author)

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

    NASA Astrophysics Data System (ADS)

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

    2016-08-01

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

  10. Oxygen transport through polyethylene terephthalate (PET) coated with plasma-polymerized acetylene at atmospheric pressure

    NASA Astrophysics Data System (ADS)

    Wemlinger, Erik; Pedrow, Patrick; Garcia-Pérez, Manuel; Sablani, Shyam

    2011-10-01

    Moser et al. have shown that oxygen transport through polyethyleneterephthalate (PET) is reduced by a factor of up to 120 when, at reduced pressure, hydrogenated amorphous carbon film with thickness less than 100 nm is applied to the PET substrate. Our work includes using atmospheric pressure cold plasma to grow a plasma-polymerized acetylene film on PET substrate and measuring reductions in oxygen transport. The reactor utilizes corona discharges and is operated at 60 Hz with a maximum voltage of 10 kV RMS. Corona streamers emanate from an array of needles with an average radius of curvature of 50 μm. The reactor utilizes a cylindrical reaction chamber with a vertical orientation such that argon carrier gas and acetylene precursor gas are introduced at the top then pass through the cold plasma activation zone and then through a grounded stainless steel mesh. Acetylene radicals are incident on the PET substrate and form plasma-polymerized acetylene film. Moser et al. have shown that oxygen transport through polyethyleneterephthalate (PET) is reduced by a factor of up to 120 when, at reduced pressure, hydrogenated amorphous carbon film with thickness less than 100 nm is applied to the PET substrate. Our work includes using atmospheric pressure cold plasma to grow a plasma-polymerized acetylene film on PET substrate and measuring reductions in oxygen transport. The reactor utilizes corona discharges and is operated at 60 Hz with a maximum voltage of 10 kV RMS. Corona streamers emanate from an array of needles with an average radius of curvature of 50 μm. The reactor utilizes a cylindrical reaction chamber with a vertical orientation such that argon carrier gas and acetylene precursor gas are introduced at the top then pass through the cold plasma activation zone and then through a grounded stainless steel mesh. Acetylene radicals are incident on the PET substrate and form plasma-polymerized acetylene film. E.M. Moser, R. Urech, E. Hack, H. Künzli, E. Müller, Thin

  11. Acetylene- and Phenylacetylene-Terminated Poly(Arylene Ether Benzimidazole)s (PAEBI's)

    NASA Technical Reports Server (NTRS)

    Connell, John W.; Hergenrother, Paul M.; Smith, Joseph G., Jr.

    1994-01-01

    Polymers prepared by first synthesizing polymers terminated with hydroxy groups, then reacting them with either 4-ethynylbenzoyl chloride or 4-fluoro-4'-phenylethynylbenzophenone. Endcapped polymers thermally cured to yield materials with attractive combination of properties. Cured acetylene-and phenylacetylene-terminated PAEBI's exhibit higher glass-transition temperatures and better retention of mechanical properties at high temperatures. Cured acetylene- and phenylacetylene-terminated polymers exhibit excellent adhesion to copper foil and polyimide film. Potentially useful as adhesives, coatings, composite matrices, fibers, films, membranes, and moldings.

  12. Efficient synthesis of β-chlorovinylketones from acetylene in chloroaluminate ionic liquids.

    PubMed

    Snelders, Dennis J M; Dyson, Paul J

    2011-08-05

    A method for the Friedel-Crafts-type insertion reaction of acetylene with acid chlorides in chloroaluminate ionic liquids is presented. The use of ionic liquids not only serves to avoid the use of carbon tetrachloride or 1,2-dichloroethane but also suppresses side reactions, notably the polymerization of acetylene, which occurs in these chlorinated solvents. Consequently, the products can be isolated using a simpler purification procedure, giving a range of aromatic and aliphatic β-chlorovinyl ketones in high yield and purity.

  13. Simulations of shock-induced mixing& combustion of an acetylene cloud in a chamber

    SciTech Connect

    Bell, J B; Day, M S; Beckner, V E; Kuhl, A L; Neuwald, P; Reichenbach, H

    2001-02-06

    In this paper we present numerical simulations of the interaction of a blast wave with an acetylene bubble in a closed chamber. We model the system using the inviscid Euler equations for a mixture of ideal gases. The formulation specifies the thermodynamic behavior of the system using a Chemkin interface and includes the capability to model combustion as the ambient air mixes with the acetylene. The simulations are performed using a three-dimensional adaptive mesh refinement algorithm based on a second-order Godunov integration scheme. Simulations are compared with experimental measurements for the same configuration.

  14. Ethylene synthesis and sensitivity in crop plants

    NASA Technical Reports Server (NTRS)

    Klassen, Stephen P.; Bugbee, Bruce

    2004-01-01

    Closed and semi-closed plant growth chambers have long been used in studies of plant and crop physiology. These studies include the measurement of photosynthesis and transpiration via photosynthetic gas exchange. Unfortunately, other gaseous products of plant metabolism can accumulate in these chambers and cause artifacts in the measurements. The most important of these gaseous byproducts is the plant hormone ethylene (C2H4). In spite of hundreds of manuscripts on ethylene, we still have a limited understanding of the synthesis rates throughout the plant life cycle. We also have a poor understanding of the sensitivity of intact, rapidly growing plants to ethylene. We know ethylene synthesis and sensitivity are influenced by both biotic and abiotic stresses, but such whole plant responses have not been accurately quantified. Here we present an overview of basic studies on ethylene synthesis and sensitivity.

  15. The ethylene signal transduction pathway in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1997-01-01

    The gaseous hormone ethylene is an important regulator of plant growth and development. Using a simple response of etiolated seedlings to ethylene as a genetic screen, genes involved in ethylene signal transduction have been identified in Arabidopsis. Analysis of two of these genes that have been cloned reveals that ethylene signalling involves a combination of a protein (ETR1) with similarity to bacterial histidine kinases and a protein (CTR1) with similarity to Raf-1, a protein kinase involved in multiple signalling cascades in eukaryotic cells. Several lines of investigation provide compelling evidence that ETR1 encodes an ethylene receptor. For the first time there is a glimpse of the molecular circuitry underlying the signal transduction pathway for a plant hormone.

  16. The ethylene response pathway in Arabidopsis

    NASA Technical Reports Server (NTRS)

    Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1997-01-01

    The simple gas ethylene influences a diverse array of plant growth and developmental processes including germination, senescence, cell elongation, and fruit ripening. This review focuses on recent molecular genetic studies, principally in Arabidopsis, in which components of the ethylene response pathway have been identified. The isolation and characterization of two of these genes has revealed that ethylene sensing involves a protein kinase cascade. One of these genes encodes a protein with similarity to the ubiquitous Raf family of Ser/Thr protein kinases. A second gene shows similarity to the prokaryotic two-component histidine kinases and most likely encodes an ethylene receptor. Additional elements involved in ethylene signaling have only been identified genetically. The characterization of these genes and mutants will be discussed.

  17. Near-infrared spectra of liquid/solid acetylene under Titan relevant conditions and implications for Cassini/VIMS detections

    NASA Astrophysics Data System (ADS)

    Singh, S.; Cornet, T.; Chevrier, V. F.; Combe, J.-Ph.; McCord, T. B.; Roe, L. A.; Le Mouélic, S.; Le Menn, E.; Wasiak, F. C.

    2016-05-01

    Acetylene is thought to be abundant on Titan according to most photochemical models. While detected in the atmosphere, its likely presence at the surface still lacks physical evidence. It is thought that solid acetylene could be a major component of Titan's lakes shorelines and dry lakebed, detected as the 5 μm-bright deposits with the Cassini/VIMS instrument. Acetylene could also be present under its liquid form as dissolved solids in Titan's methane-ethane lakes, as emphasized by thermodynamics studies. This paper is devoted to the near-infrared spectroscopy study of acetylene under solid and liquid phases between 1 and 2.2 μm, synthesized in a Titan simulation chamber that is able to reproduce extreme temperature conditions. From experiments, we observed a ∼10% albedo increase between liquid acetylene at 193-188 K and solid acetylene at 93 K. Using the NIR spectroscopy technique we successfully calculated the reflectivity ratio of solid/liquid acetylene as 1.13. The second difference we observed between liquid and solid acetylene is a shift in the major absorption band detected at 1.54 μm, the shift of ∼0.01 μm occurring toward higher wavelength. In order to assess the detectability of acetylene on Titan using the Cassini/VIMS instrument, we adapted our spectra to the VIMS spectral resolution. The spectral band at 1.55 μm and a negative slope at 2.0 μm falls in the Cassini/VIMS atmospheric windows over several VIMS infrared spectels, thus Cassini/VIMS should be able to detect acetylene.

  18. Comparison of combustion characteristics of ASTM A-1, propane, and natural-gas fuels in an annular turbojet combustor

    NASA Technical Reports Server (NTRS)

    Wear, J. D.; Jones, R. E.

    1973-01-01

    The performance of an annular turbojet combustor using natural-gas fuel is compared with that obtained using ASTM A-1 and propane fuels. Propane gas was used to simulate operation with vaporized kerosene fuels. The results obtained at severe operating conditions and altitude relight conditions show that natural gas is inferior to both ASTM A-1 and propane fuels. Combustion efficiencies were significantly lower and combustor pressures for relight were higher with natural-gas fuel than with the other fuels. The inferior performance of natural gas is shown to be caused by the chemical stability of the methane molecule.

  19. Computational study on C-H...π interactions of acetylene with benzene, 1,3,5-trifluorobenzene and coronene.

    PubMed

    Dinadayalane, Tandabany C; Paytakov, Guvanchmyrat; Leszczynski, Jerzy

    2013-07-01

    Meta-hybrid density functional theory calculations using M06-2X/6-31+G(d,p) and M06-2X/6-311+G(d,p) levels of theory have been performed to understand the strength of C-H(…)π interactions of two possible types for benzene-acetylene, 1,3,5-trifluorobenzene-acetylene and coronene-acetylene complexes. Our study reveals that the C-H(...)π interaction complex where acetylene located above to the center of benzene ring (classical T-shaped) is the lowest energy structure. This structure is twice more stable than the configuration characterized by H atom of benzene interacting with the π-cloud of acetylene. The binding energy of 2.91 kcal/mol calculated at the M06-2X/6-311+G(d,p) level for the lowest energy configuration (1A) is in very good agreement with the experimental binding energy of 2.7 ± 0.2 kcal/mol for benzene-acetylene complex. Interestingly, the C-H(...)π interaction of acetylene above to the center of the aromatic ring is not the lowest energy configuration for 1,3,5-trifluorobenzene-acetylene and coronene-acetylene complexes. The lowest energy configuration (2A) for the former complex possesses both C-H(...)π interaction and C-H(...)F hydrogen bond, while the lowest energy structure for the coronene-acetylene complex involves both π-π and C-H(...)π interactions. C-H stretching vibrational frequencies and the frequency shifts are reported and analyzed for all of the configurations. We observed red-shift of the vibrational frequency for the stretching mode of the C-H bond that interacts with the π-cloud. Acetylene in the lowest-energy structures of the complexes exhibits significant red-shift of the C-H stretching frequency and change in intensity of the corresponding vibrational frequency, compared to bare acetylene. We have examined the molecular electrostatic potential on the surfaces of benzene, 1,3,5-trifluorobenzene, coronene and acetylene to explain the binding strengths of various complexes studied here.

  20. Ethylene-dependent/ethylene-independent ABA regulation of tomato plants colonized by arbuscular mycorrhiza fungi.

    PubMed

    Martín-Rodríguez, José Ángel; León-Morcillo, Rafael; Vierheilig, Horst; Ocampo, Juan Antonio; Ludwig-Müller, Jutta; García-Garrido, José Manuel

    2011-04-01

    We investigated the relationship between ABA and ethylene regulating the formation of the arbuscular mycorrhiza (AM) symbiosis in tomato (Solanum lycopersicum) plants and tried to define the specific roles played by each of these phytohormones in the mycorrhization process. We analysed the impact of ABA biosynthesis inhibition on mycorrhization by Glomus intraradices in transgenic tomato plants with an altered ethylene pathway. We also studied the effects on mycorrhization in sitiens plants treated with the aminoethoxyvinyl glycine hydrochloride (AVG) ethylene biosynthesis inhibitor and supplemented with ABA. In addition, the expression of plant and fungal genes involved in the mycorrhization process was studied. ABA biosynthesis inhibition qualitatively altered the parameters of mycorrhization in accordance with the plant's ethylene perception and ethylene biosynthesis abilities. Inhibition of ABA biosynthesis in wild-type plants negatively affected all the mycorrhization parameters studied, while tomato mutants impaired in ethylene synthesis only showed a reduced arbuscular abundance in mycorrhizal roots. Inhibition of ethylene synthesis in ABA-deficient sitiens plants increased the intensity of mycorrhiza development, while ABA application rescued arbuscule abundance in the root's mycorrhizal zones. The results of our study show an antagonistic interaction between ABA and ethylene, and different roles of each of the two hormones during AM formation. This suggests that a dual ethylene-dependent/ethylene-independent mechanism is involved in ABA regulation of AM formation.

  1. Ethylene and flower longevity in Alstroemeria: relationship between tepal senescence, abscission and ethylene biosynthesis.

    PubMed

    Wagstaff, Carol; Chanasut, Usawadee; Harren, Frans J M; Laarhoven, Luc-Jan; Thomas, Brian; Rogers, Hilary J; Stead, Anthony D

    2005-03-01

    Senescence of floral organs is broadly divided into two groups: those that exhibit sensitivity to exogenous ethylene and those that do not. Endogenous ethylene production from the former group is via a well-characterized biochemical pathway and is either due to developmental or pollination-induced senescence. Many flowers from the order Liliales are characterized as ethylene-insensitive since they do not appear to produce endogenous ethylene, or respond to exogenous ethylene treatments, however, the majority of cases studied are wilting flowers, rather than those where life is terminated by perianth abscission. The role of ethylene in the senescence and abscission of Alstroemeria peruviana cv. Rebecca and cv. Samora tepals was previously unclear, with silver treatments recommended for delaying leaf rather than flower senescence. In the present paper the effects of exogenous ethylene, 2-chloroethylphosphonic acid (CEPA) and silver thiosulphate (STS) treatments on tepal senescence and abscission have been investigated. Results indicate that sensitivity to ethylene develops several days after flower opening such that STS only has a limited ability to delay tepal abscission. Detachment force measurements indicate that cell separation events are initiated after anthesis. Endogenous ethylene production was measured using laser photoacoustics and showed that Alstroemeria senesce independently of ethylene production, but that an extremely small amount of ethylene (0.15 nl flower(-1) h(-1)) is produced immediately prior to abscission. Investigation of the expression of genes involved in ethylene biosysnthesis by semi-quantitative RT-PCR indicated that transcriptional regulation is likely to be at the level of ACC oxidase, and that the timing of ACC oxidase gene expression is coincident with development of sensitivity to exogenous ethylene.

  2. Ethylene Glycol Metabolism by Pseudomonas putida

    PubMed Central

    Mückschel, Björn; Simon, Oliver; Klebensberger, Janosch; Graf, Nadja; Rosche, Bettina; Altenbuchner, Josef; Pfannstiel, Jens; Huber, Armin

    2012-01-01

    In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the temporal accumulation of glycolic acid and glyoxylic acid for strain KT2440. This accumulation was further increased by targeted mutagenesis. The key enzymes and specific differences between the two strains were identified by comparative proteomics. In P. putida JM37, tartronate semialdehyde synthase (Gcl), malate synthase (GlcB), and isocitrate lyase (AceA) were found to be induced in the presence of ethylene glycol or glyoxylic acid. Under the same conditions, strain KT2440 showed induction of AceA only. Despite this difference, the two strains were found to use similar periplasmic dehydrogenases for the initial oxidation step of ethylene glycol, namely, the two redundant pyrroloquinoline quinone (PQQ)-dependent enzymes PedE and PedH. From these results we constructed a new pathway for the metabolism of ethylene glycol in P. putida. Furthermore, we conclude that Pseudomonas putida might serve as a useful platform from which to establish a whole-cell biocatalyst for the production of glyoxylic acid from ethylene glycol. PMID:23023748

  3. Ethylene-forming enzyme and bioethylene production

    PubMed Central

    2014-01-01

    Worldwide, ethylene is the most produced organic compound. It serves as a building block for a wide variety of plastics, textiles, and chemicals, and a process has been developed for its conversion into liquid transportation fuels. Currently, commercial ethylene production involves steam cracking of fossil fuels, and is the highest CO2-emitting process in the chemical industry. Therefore, there is great interest in developing technology for ethylene production from renewable resources including CO2 and biomass. Ethylene is produced naturally by plants and some microbes that live with plants. One of the metabolic pathways used by microbes is via an ethylene-forming enzyme (EFE), which uses α-ketoglutarate and arginine as substrates. EFE is a promising biotechnology target because the expression of a single gene is sufficient for ethylene production in the absence of toxic intermediates. Here we present the first comprehensive review and analysis of EFE, including its discovery, sequence diversity, reaction mechanism, predicted involvement in diverse metabolic modes, heterologous expression, and requirements for harvesting of bioethylene. A number of knowledge gaps and factors that limit ethylene productivity are identified, as well as strategies that could guide future research directions. PMID:24589138

  4. Current methods for detecting ethylene in plants

    PubMed Central

    Cristescu, Simona M.; Mandon, Julien; Arslanov, Denis; De Pessemier, Jérôme; Hermans, Christian; Harren, Frans J. M.

    2013-01-01

    Background In view of ethylene's critical developmental and physiological roles the gaseous hormone remains an active research topic for plant biologists. Progress has been made to understand the ethylene biosynthesis pathway and the mechanisms of perception and action. Still numerous questions need to be answered and findings to be validated. Monitoring gas production will very often complete the picture of any ethylene research topic. Therefore the search for suitable ethylene measuring methods for various plant samples either in the field, greenhouses, laboratories or storage facilities is strongly motivated. Scope This review presents an update of the current methods for ethylene monitoring in plants. It focuses on the three most-used methods – gas chromatography detection, electrochemical sensing and optical detection – and compares them in terms of sensitivity, selectivity, time response and price. Guidelines are provided for proper selection and application of the described sensor methodologies and some specific applications are illustrated of laser-based detector for monitoring ethylene given off by Arabidopsis thaliana upon various nutritional treatments. Conclusions Each method has its advantages and limitations. The choice for the suitable ethylene sensor needs careful consideration and is driven by the requirements for a specific application. PMID:23243188

  5. Internal acetylene unit as a cross-link site for polyimides

    SciTech Connect

    Takeichi, T.; Tanikawa, M.

    1995-12-01

    We have been studying on the cross-linking behavior of internal acetylenes linked meta-meta to aromatic connecting units which were introduced into the polyimide backbone utilizing 3,3`-diaminodiphenylacetylene (m-intA). In this study, we studied on the cross-linking behavior of internal acetylenes linked para-para to aromatic connecting units. The internal acetylene units were introduced into the polyimide backbone by the reaction of 4,4`-diaminodiphenylacetylene (p-intA) with such acid anhydrides as biphenyltetracarboxylic dianhydride (BPDA), pyromellitic dianhydride (PMDA), and 2,2-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride (6FDA). The polyimides showed exotherm on DSC: The onset of the exotherm of p-intA appeared at around 330-390{degrees}C, which is 10-50{degrees}C higher than that of m-intA. The exotherm disappeared after thermal treatment at 400{degrees}C, suggesting the progress of crosslinking between acetylene units. The polyimides cured at 350{degrees}C or 400{degrees}C showed increased Tg and improved physical properties at high temperatures as confirmed by viscoelastic analyses. It was also made clear that polyimides containing p-intA showed higher modulus compared with polyimides containing m-intA, especially when coupled with BPDA and PMDA.

  6. Methane emissions measured at two California landfills by OTM-10 and an acetylene tracer method

    EPA Science Inventory

    Methane emissions were measured at two municipal solid waste landfills in California using static flux chambers, an optical remote sensing approach known as vertical radial plume mapping (VRPM) using a tunable diode laser (TDL) and a novel acetylene tracer method. The tracer meth...

  7. An upper limit to the acetylene abundance toward BN in the orion molecular cloud

    NASA Technical Reports Server (NTRS)

    Knacke, R. F.; Kim, Y. H.; Irvine, W. M.

    1989-01-01

    A search for the acetylene (C2H2) nu3 infrared vibration-rotation absorption near 3 microns toward the Becklin-Neugebauer source in the Orion molecular cloud is reported. The relative abundance of C2H2/CO in the quiescent gas is less than 0.003.

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

    PubMed

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

    2009-02-12

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

  9. A Safe and Easy Classroom Demonstration of the Generation of Acetylene Gas.

    ERIC Educational Resources Information Center

    Cox, Marilyn Blagg; Krause, Paul

    1994-01-01

    In this demonstration of the generation and combustion of acetylene, calcium carbide and water are allowed to react in a latex examination glove. Two student volunteers perform the demonstration with instructor guidance. This safe, popular demonstration, originally intended to illustrate the alkyne family of compounds, can be used with a variety…

  10. Specific surface modification of the acetylene-linked glycolipid vesicle by click chemistry.

    PubMed

    Ito, Hidehiro; Kamachi, Toshiaki; Yashima, Eiji

    2012-06-07

    A novel glycolipid with a terminal acetylene was synthesized and used to prepare unilamellar vesicles. Using these vesicles, a convenient method was developed for the specific modification of the vesicle surface using the photoresponsive copper complex [Cu(OH(2))(cage)] as the catalyst for a click reaction.

  11. Reaction of β-enaminones and acetylene dicarboxylates: synthesis of substituted 1,2-dihydropyridinones.

    PubMed

    Nagaraju, Vemu; Purnachander, Dalovai; Mangina, N S V M Rao; Suresh, Surisetti; Sridhar, Balasubramanian; Karunakar, Galla V

    2015-03-14

    Synthesis of substituted 1,2-dihydropyridinones is described in a one pot reaction of β-enaminones and acetylene dicarboxylates where new C-C and C-N bonds were formed. The title compounds were obtained in moderate to good yields.

  12. Mechanism of tungsten-dependent acetylene hydratase from quantum chemical calculations.

    PubMed

    Liao, Rong-Zhen; Yu, Jian-Guo; Himo, Fahmi

    2010-12-28

    Acetylene hydratase is a tungsten-dependent enzyme that catalyzes the nonredox hydration of acetylene to acetaldehyde. Density functional theory calculations are used to elucidate the reaction mechanism of this enzyme with a large model of the active site devised on the basis of the native X-ray crystal structure. Based on the calculations, we propose a new mechanism in which the acetylene substrate first displaces the W-coordinated water molecule, and then undergoes a nucleophilic attack by the water molecule assisted by an ionized Asp13 residue at the active site. This is followed by proton transfer from Asp13 to the newly formed vinyl anion intermediate. In the subsequent isomerization, Asp13 shuttles a proton from the hydroxyl group of the vinyl alcohol to the α-carbon. Asp13 is thus a key player in the mechanism, but also W is directly involved in the reaction by binding and activating acetylene and providing electrostatic stabilization to the transition states and intermediates. Several other mechanisms are also considered but the energetic barriers are found to be very high, ruling out these possibilities.

  13. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Specification 8AL steel cylinders with porous...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.60 Specification 8AL steel cylinders with porous fillings for acetylene. (a) Type and service pressure. A DOT 8AL cylinder is a seamless steel cylinder...

  14. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Specification 8AL steel cylinders with porous...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.60 Specification 8AL steel cylinders with porous fillings for acetylene. (a) Type and service pressure. A DOT 8AL cylinder is a seamless steel cylinder...

  15. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Specification 8AL steel cylinders with porous...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.60 Specification 8AL steel cylinders with porous fillings for acetylene. (a) Type and service pressure. A DOT 8AL cylinder is a seamless steel cylinder...

  16. 49 CFR 178.60 - Specification 8AL steel cylinders with porous fillings for acetylene.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Specification 8AL steel cylinders with porous...) SPECIFICATIONS FOR PACKAGINGS Specifications for Cylinders § 178.60 Specification 8AL steel cylinders with porous fillings for acetylene. (a) Type and service pressure. A DOT 8AL cylinder is a seamless steel cylinder...

  17. Directional deprotonation ionization of acetylene in asymmetric two-color laser fields

    NASA Astrophysics Data System (ADS)

    Song, Qiying; Gong, Xiaochun; Ji, Qinying; Lin, Kang; Pan, Haifeng; Ding, Jingxin; Zeng, Heping; Wu, Jian

    2015-05-01

    We experimentally investigate the deprotonation dissociative double ionization of an acetylene molecule by an asymmetric two-color laser pulse. We find that the ejection direction of the proton, and hence the directional C-H bond breaking of a polyatomic hydrocarbon molecule, can be controlled by finely tuning the phase of a two-color laser pulse.

  18. [4 + 2] Annulation of Donor-Acceptor Cyclopropanes with Acetylenes Using 1,2-Zwitterionic Reactivity.

    PubMed

    Novikov, Roman A; Tarasova, Anna V; Denisov, Dmitry A; Borisov, Denis D; Korolev, Victor A; Timofeev, Vladimir P; Tomilov, Yury V

    2017-02-23

    A new process for the [4 + 2] annulation of donor-acceptor cyclopropanes with acetylenes under the effect of anhydrous GaCl3 using 1,2-zwitterion reactivity was elaborated. The reaction opens access to substituted dihydronaphthalenes, naphthalenes, and other fused carbocycles. The direction of the reaction can be efficiently controlled by temperature.

  19. Mechanism of tungsten-dependent acetylene hydratase from quantum chemical calculations

    PubMed Central

    Liao, Rong-Zhen; Yu, Jian-Guo; Himo, Fahmi

    2010-01-01

    Acetylene hydratase is a tungsten-dependent enzyme that catalyzes the nonredox hydration of acetylene to acetaldehyde. Density functional theory calculations are used to elucidate the reaction mechanism of this enzyme with a large model of the active site devised on the basis of the native X-ray crystal structure. Based on the calculations, we propose a new mechanism in which the acetylene substrate first displaces the W-coordinated water molecule, and then undergoes a nucleophilic attack by the water molecule assisted by an ionized Asp13 residue at the active site. This is followed by proton transfer from Asp13 to the newly formed vinyl anion intermediate. In the subsequent isomerization, Asp13 shuttles a proton from the hydroxyl group of the vinyl alcohol to the α-carbon. Asp13 is thus a key player in the mechanism, but also W is directly involved in the reaction by binding and activating acetylene and providing electrostatic stabilization to the transition states and intermediates. Several other mechanisms are also considered but the energetic barriers are found to be very high, ruling out these possibilities. PMID:21149684

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

    PubMed

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

    2016-11-09

    Herein we report an enhanced triboelectric nanogenerator (TENG) based on the contact-separation mode between a patterned film of polydimethylsiloxane (PDMS) with a semimetallic elastomer of poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) and a nylon fiber film. The addition of ethylene glycol to the PEDOT:PSS film improves the functionality of the TENG significantly, yielding promising applicability in both indoor and outdoor (i.e., under sunlight) environments, with the maximum instantaneous power of 0.09 mW (indoors) and 0.2 mW (outdoors) for the load resistance of 3.8 MΩ. The device can also generate 11.2 V and 0.08 μA cm(-2) in response to the forearm movement of a human. Additionally, by replacing the bare nylon fiber in the TENG design with a Ag@ZnO/nylon fiber film, a self-powered active sensor (triboelectric nanogenerator-based sensor; TENS) has been realized to detect acetylene (C2H2) gas. The TENS exhibits excellent sensitivity of 70.9% (indoors) and 89% (outdoors) to C2H2 gas of 1000 ppm concentration. The proposed approach for harvesting energy and sensing can be advantageous in practical applications and may stimulate new research that will enhance nanogenerators as well as wearable, self-powered active sensors.

  1. 21 CFR 177.1312 - Ethylene-carbon monoxide copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-carbon monoxide copolymers. 177.1312... Use Food Contact Surfaces § 177.1312 Ethylene-carbon monoxide copolymers. The ethylene-carbon monoxide... of this section, ethylene-carbon monoxide copolymers (CAS Reg. No. 25052-62-4) consist of the...

  2. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  3. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  4. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  5. 21 CFR 172.770 - Ethylene oxide polymer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a...

  6. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  7. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  8. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  9. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  10. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  11. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  12. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  13. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO)...

  14. 46 CFR 151.50-12 - Ethylene oxide.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at...

  15. 21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-vinyl acetate copolymers. 177.1350... Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate... with the following prescribed conditions: (a)(1) Ethylene-vinyl acetate copolymers consist of...

  16. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Ethylene-acrylic acid copolymers. 177.1310 Section... Use Food Contact Surfaces § 177.1310 Ethylene-acrylic acid copolymers. The ethylene-acrylic acid... for use in contact with food subject to the provisions of this section. (a) The ethylene-acrylic...

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

    PubMed Central

    Rosner, B M; Schink, B

    1995-01-01

    Acetylene hydratase of the mesophilic fermenting bacterium Pelobacter acetylenicus catalyzes the hydration of acetylene to acetaldehyde. Growth of P. acetylenicus with acetylene and specific acetylene hydratase activity depended on tungstate or, to a lower degree, molybdate supply in the medium. The specific enzyme activity in cell extract was highest after growth in the presence of tungstate. Enzyme activity was stable even after prolonged storage of the cell extract or of the purified protein under air. However, enzyme activity could be measured only in the presence of a strong reducing agent such as titanium(III) citrate or dithionite. The enzyme was purified 240-fold by ammonium sulfate precipitation, anion-exchange chromatography, size exclusion chromatography, and a second anion-exchange chromatography step, with a yield of 36%. The protein was a monomer with an apparent molecular mass of 73 kDa, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The isoelectric point was at pH 4.2. Per mol of enzyme, 4.8 mol of iron, 3.9 mol of acid-labile sulfur, and 0.4 mol of tungsten, but no molybdenum, were detected. The Km for acetylene as assayed in a coupled photometric test with yeast alcohol dehydrogenase and NADH was 14 microM, and the Vmax was 69 mumol.min-1.mg of protein-1. The optimum temperature for activity was 50 degrees C, and the apparent pH optimum was 6.0 to 6.5. The N-terminal amino acid sequence gave no indication of resemblance to any enzyme protein described so far. PMID:7592321

  18. Examining Contributions to Line Shapes in the ν_1 + ν_3 Band of Acetylene

    NASA Astrophysics Data System (ADS)

    Cich, Matthew J.; Caiola, Salvatore M.; Lee, Stephen W.; Lopez, Gary V.; Sears, Trevor J.; Forthomme, Damien; McRaven, C. P.; Hall, Gregory E.; Mantz, A. W.

    2013-06-01

    Using an extended cavity diode laser locked to a frequency comb, line shapes in the ν_1 + ν_3 combination band of acetylene have been studied. The frequency stability of this experiment produces high accuracy measurements that provide rigorous tests of line shape theories. Measurements of the P(11) line shape were made for pure acetylene and acetylene-nitrogen gas mixtures at a series of temperatures between 125 K and 296 K. Using the speed-dependent Voigt line shape model, parameters were determined by fitting data for all temperatures and pressures in a single multispectrum analysis. The resulting parameters successfully reproduce the measured line shapes and are valid for the acetylene-nitrogen system over the range of temperatures studied and combined pressures of up to 1 atmosphere. P(11) is isolated with respect to hot band transitions and neighboring transitions of the same band, but this is an unusual case. To explore the effects of overlapping lines, the P(1) transition was measured in a series of pure acetylene measurements in a congested spectral region. Overlapping hot band lines of measurable intensities were modeled and line shape paramters were simultaneously determined for these along with the P(1) line. Additionally, the effects of line mixing between overlapping ν_1 + ν_3 lines were explored using an appropriate line mixing model. Acknowledgments: Work at Brookhaven National Laboratory was carried out under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and supported by its Office of Basic Energy Sciences, Division of Chemical Sciences, Geosciences and Biosciences.

  19. Propane respiration jump-starts microbial response to a deep oil spill.

    PubMed

    Valentine, David L; Kessler, John D; Redmond, Molly C; Mendes, Stephanie D; Heintz, Monica B; Farwell, Christopher; Hu, Lei; Kinnaman, Franklin S; Yvon-Lewis, Shari; Du, Mengran; Chan, Eric W; Garcia Tigreros, Fenix; Villanueva, Christie J

    2010-10-08

    The Deepwater Horizon event resulted in suspension of oil in the Gulf of Mexico water column because the leakage occurred at great depth. The distribution and fate of other abundant hydrocarbon constituents, such as natural gases, are also important in determining the impact of the leakage but are not yet well understood. From 11 to 21 June 2010, we investigated dissolved hydrocarbon gases at depth using chemical and isotopic surveys and on-site biodegradation studies. Propane and ethane were the primary drivers of microbial respiration, accounting for up to 70% of the observed oxygen depletion in fresh plumes. Propane and ethane trapped in the deep water may therefore promote rapid hydrocarbon respiration by low-diversity bacterial blooms, priming bacterial populations for degradation of other hydrocarbons in the aging plume.

  20. [Fire disaster due to deflagration of a propane gas-air mixture].

    PubMed

    Nadjem, Hadi; Vogt, Susanne; Simon, Karl-Heinz; Pollak, Stefan; Geisenberger, Dorothee; Kramer, Lena; Pircher, Rebecca; Perdekampl, Markus Große; Thierauf-Emberger, Annette

    2015-01-01

    On 26 Nov 2012, a serious fire occurred at Neustadt/Black Forest in which 14 persons in a sheltered workshop died and 10 other individuals were injured. The fire was caused by the unbridled escape of propane gas due to accidental disconnection of the screw fixing between a gas bottle and a catalytic heater. Deflagration of the propane gas-air mixture set the workshop facilities on fire. In spite of partly extensive burns the fatally injured victims could be rapidly identified. The results of the fire investigations at the scene and the autopsy findings are presented. Carboxyhemoglobin concentrations ranged between 8 and 56 % and signs of fire fume inhalation were present in all cases. Three victims had eardrum ruptures due to the sudden increase in air pressure during the deflagration.

  1. Observation of propane cluster size distributions during nucleation and growth in a Laval expansion

    NASA Astrophysics Data System (ADS)

    Ferreiro, Jorge J.; Chakrabarty, Satrajit; Schläppi, Bernhard; Signorell, Ruth

    2016-12-01

    We report on molecular-level studies of the condensation of propane gas and propane/ethane gas mixtures in the uniform (constant pressure and temperature) postnozzle flow of Laval expansions using soft single-photon ionization by vacuum ultraviolet light and mass spectrometric detection. The whole process, from the nucleation to the growth to molecular aggregates of sizes of several nanometers (˜5 nm), can be monitored at the molecular level with high time-resolution (˜3 μs) for a broad range of pressures and temperatures. For each time, pressure, and temperature, a whole mass spectrum is recorded, which allows one to determine the critical cluster size range for nucleation as well as the kinetics and mechanisms of cluster-size specific growth. The detailed information about the size, composition, and population of individual molecular clusters upon condensation provides unique experimental data for comparison with future molecular-level simulations.

  2. Hydrogen Safety Issues Compared to Safety Issues with Methane andPropane

    SciTech Connect

    Green, Michael A.

    2005-08-20

    The hydrogen economy is not possible if the safety standards currently applied to liquid hydrogen and hydrogen gas by many laboratories are applied to devices that use either liquid or gaseous hydrogen. Methane and propane are commonly used by ordinary people without the special training. This report asks, 'How is hydrogen different from flammable gasses that are commonly being used all over the world?' This report compares the properties of hydrogen, methane and propane and how these properties may relate to safety when they are used in both the liquid and gaseous state. Through such an analysis, sensible safety standards for the large-scale (or even small-scale) use of liquid and gaseous hydrogen systems can be developed. This paper is meant to promote discussion of issues related to hydrogen safety so that engineers designing equipment can factor sensible safety standards into their designs.

  3. Thermophysical properties of propane from 85 to 700/sup 0/K at pressures to 70 MPa

    SciTech Connect

    Goodwin, R.D.; Haynes, W.M.

    1982-04-01

    Thermophysical properties of propane are tabulated at integral temperatures over the entire range of fluid states from 85 to 700/sup 0/K along isobars to 70 MPa by using a modified form of the nonanalytic equation of state. These tables, along with a table for the saturated liquid, include values for density, compressibility factor, internal energy, enthalpy, entropy, heat capacities, fugacity, sound velocity, dielectric constant, and isochore and isotherm derivatives. In addition to the equation of state, equations are presented for vapor pressures, orthobaric vapor and liquid densities, ideal gas properties, virial coefficients, dielectric constants, heats of vaporization, melting C, and orthobaric liquid specific heats, enthalpies, and entropies. Coefficients were determined by a least squares fit of selected experimental data, including several new sets of data not included in previous propane correlations. Comparisons between experimental and calculated values are given, including those for sound velocities, heat capacities, P-rho-T data, etc.

  4. Electrochemical promotion of propane oxidation on Pt deposited on a dense β"-Al2O3 ceramic Ag+ conductor

    NASA Astrophysics Data System (ADS)

    Tsampas, Michail; Kambolis, Anastasios; Obeid, Emil; Lizarraga, Leonardo; Sapountzi, Foteini; Vernoux, Philippe

    2013-08-01

    A new kind of electrochemical catalyst based on a Pt porous catalyst film deposited on a β"-Al2O3 ceramic Ag+ conductor was developed and evaluated during propane oxidation. It was observed that upon anodic polarization, the rate of propane combustion was significantly electropromoted up to 400%. Moreover, for the first time, exponential increase of the catalytic rate was evidenced during galvanostatic transient experiment in excellent agreement with EPOC equation.

  5. Analysis of the site-specific carbon isotope composition of propane by gas source isotope ratio mass spectrometer

    NASA Astrophysics Data System (ADS)

    Piasecki, Alison; Sessions, Alex; Lawson, Michael; Ferreira, A. A.; Neto, E. V. Santos; Eiler, John M.

    2016-09-01

    Site-specific isotope ratio measurements potentially provide valuable information about the formation and degradation of complex molecules-information that is lost in conventional bulk isotopic measurements. Here we discuss the background and possible applications of such measurements, and present a technique for studying the site-specific carbon isotope composition of propane at natural abundance based on mass spectrometric analysis of the intact propane molecule and its fragment ions. We demonstrate the feasibility of this approach through measurements of mixtures of natural propane and propane synthesized with site-specific 13C enrichment, and we document the limits of precision of our technique. We show that mass balance calculations of the bulk δ13C of propane based on our site-specific measurements is generally consistent with independent constraints on bulk δ13C. We further demonstrate the accuracy of the technique, and illustrate one of its simpler applications by documenting the site-specific carbon isotope signature associated with gas phase diffusion of propane, confirming that our measurements conform to the predictions of the kinetic theory of gases. This method can be applied to propane samples of moderate size (tens of micromoles) isolated from natural gases. Thus, it provides a means of studying the site-specific stable isotope systematics of propane at natural isotope abundances on sample sizes that are readily recovered from many natural environments. This method may also serve as a model for future techniques that apply high-resolution mass spectrometry to study the site-specific isotopic distributions of larger organic molecules, with potential applications to biosynthesis, forensics and other geochemical subjects.

  6. Catalytic ozonation of propanal using wood fly ash and metal oxide nanoparticle impregnated carbon.

    PubMed

    Kastner, James R; Ganagavaram, Rangan; Kolar, Praveen; Teja, Amyn; Xu, Chunbao

    2008-01-15

    Catalytic ozonation of propanal at ambient temperatures (23-25 degrees C) was investigated by varying propanal and ozone concentrations and catalyst type. The catalysts tested included wood fly ash (WFA), magnetically separated ash, synthetic hematite and magnetite, and metal oxide nanoparticle impregnated activated carbon and peanut hull char. A power law model independent of ozone concentration for WFA (r(w), moles g(-1) s(-1)) and magnetite (r(m)) were, respectively, r(w) = k'(w) C(R(0.89)) and r(m) = k'(m)C(R(1.55)), where kw, and k'(m) were 2.36 x 10(-6) g(-1) s(-1) (moles)(-0.11) (m3)(0.89) and 6.5 x 10(-4) g(-1) s(-1) (moles)(-0.55) (m3)(1.55), respectively (5-15 ppmv). Magnetite and hematite present in the WFA were theorized to be the primary active sites, since magnetically separated WFA had a significantly higher reaction rate (approximately 12x, mol m(-2) s(-1)) than that of WFA. X-ray diffraction analysis demonstrated a qualitative increase in magnetite and hematite in the magnetically separated ash, and synthetic magnetite and hematite had reaction rates >80x and 200x that of WFA or activated carbon (surface area basis). Supercritical deposition of hematite on/in peanut hull char successfully generated a porous, pelleted catalystfrom an agricultural residue capable of oxidizing propanal at rates 12x activated carbon and similar to commercially available catalysts (per mass basis). Water vapor significantly increased the propanal reaction rate when using wood fly ash and activated carbon.

  7. Numerical and experimental analysis of propane-hydrogen mixture ignition in air

    NASA Astrophysics Data System (ADS)

    Sevrouk, K. L.; Krivosheyev, P. N.; Penyazkov, O. G.; Torohov, S. A.; Titova, N. S.; Starik, A. M.

    2016-11-01

    The addition of hydrogen to the various hydrocarbon fuels being examined as a promising method for increasing the efficiency of the engine while improving their emission characteristics. This work is dedicated to experimental investigation of the ignition delay time C3H8-H2 mixture in the air and analysis of the mechanisms responsible for the acceleration of chain reactions with the addition of hydrogen in propane, based on numerical simulation.

  8. Update from the Analysis of High Resolution Propane Spectra and the Interpretation of Titan's Infrared Spectra

    NASA Astrophysics Data System (ADS)

    Klavans, V.; Nixon, C.; Hewagama, T.; Jennings, D. E.

    2012-04-01

    Titan has an extremely thick atmosphere dominated by nitrogen, but includes a range of trace species such as hydrocarbons and nitriles. One such hydrocarbon is propane (C3H8). Propane has 21 active IR bands covering broad regions of the mid-infrared. Therefore, its ubiquitous signature may potentially mask weaker signatures of other undetected species with important roles in Titan's chemistry. Cassini's Composite Infrared Spectrometer (CIRS) observations of Titan's atmosphere hint at the presence of such molecules. Unfortunately, C3H8 line atlases for the vibration bands ν8, ν21, ν20, and ν7 (869, 922, 1054, and 1157 cm-1, respectively) are not currently available for subtracting the C3H8 signal to reveal, or constrain, the signature of underlying chemical species. Using spectra previously obtained by Jennings, D. E., et al. at the McMath-Pierce FTIR at Kitt Peak, AZ, as the source and automated analysis utilities developed for this application, we are compiling an atlas of spectroscopic parameters for propane that characterize the ro-vibrational transitions in the above bands. In this paper, we will discuss our efforts for inspecting and fitting the aforementioned bands, present updated results for spectroscopic parameters including absolute line intensities and transition frequencies in HITRAN and GEISA formats, and show how these optical constants will be used in searching for other trace chemical species in Titan's atmosphere. Our line atlas for the ν21 band contains a total number of 2971 lines. The band integrated strength calculated for the ν21 band is 1.003 cm-1/(cm-atm). Fig. 1: Demonstration of Gaussian fit for sample spectral region 927.25 to 927.50 cm-1 (ν21). References: Jennings, D. E., et al.: "Foreign-gas pressure broadening parameters of propane near 748 cm-1". JQSRT, Vol. 42, pp. 399-403, 1989.

  9. Analysis of Ignition Behavior in a Turbocharged Direct Injection Dual Fuel Engine Using Propane and Methane as Primary Fuels

    SciTech Connect

    Polk, A. C.; Gibson, C. M.; Shoemaker, N. T.; Srinivasan, K. K.; Krishnan, S. R.

    2013-05-24

    This paper presents experimental analyses of the ignition delay (ID) behavior for diesel-ignited propane and diesel-ignited methane dual fuel combustion. Two sets of experiments were performed at a constant speed (1800 rev/min) using a 4-cylinder direct injection diesel engine with the stock ECU and a wastegated turbocharger. First, the effects of fuel-air equivalence ratios (© pilot ¼ 0.2-0.6 and © overall ¼ 0.2-0.9) on IDs were quantified. Second, the effects of gaseous fuel percent energy substitution (PES) and brake mean effective pressure (BMEP) (from 2.5 to 10 bar) on IDs were investigated. With constant © pilot (> 0.5), increasing © overall with propane initially decreased ID but eventually led to premature propane autoignition; however, the corresponding effects with methane were relatively minor. Cyclic variations in the start of combustion (SOC) increased with increasing © overall (at constant © pilot), more significantly for propane than for methane. With increasing PES at constant BMEP, the ID showed a nonlinear (initially increasing and later decreasing) trend at low BMEPs for propane but a linearly decreasing trend at high BMEPs. For methane, increasing PES only increased IDs at all BMEPs. At low BMEPs, increasing PES led to significantly higher cyclic SOC variations and SOC advancement for both propane and methane. Finally, the engine ignition delay (EID) was also shown to be a useful metric to understand the influence of ID on dual fuel combustion.

  10. Michigan residential heating oil and propane price survey: 1995--1996 heating season. Final report

    SciTech Connect

    Moriarty, C.

    1996-05-01

    This report summarizes the results of a survey of residential No. 2 distillate fuel (home heating oil) and liquefied petroleum gas (propane) prices over the 1995--1996 heating season in Michigan. The Michigan`s Public Service Commission (MPSC) conducted the survey under a cooperative agreement with the US Department of Energy`s (DOE) Energy Information Administration (EIA). This survey was funded in part by a grant from the DOE. From October 1995 through March 1996, the MPSC surveyed participating distributors by telephone for current residential retail home heating oil and propane prices. The MPSC transmitted the data via a computer modem to the EIA using the Petroleum Electronic Data Reporting Option (PEDRO). Survey results were published in aggregate on the MPSC World Wide Web site at http://ermisweb.state.mi.us/shopp. The page was updated with both residential and wholesale prices immediately following the transmission of the data to the EIA. The EIA constructed the survey using a sample of Michigan home heating oil and propane retailers. The sample accounts for different sales volumes, geographic location, and sources of primary supply.

  11. Theoretical Investigation of the Gas-Phase Reaction of CrO(+) with Propane.

    PubMed

    Beck, Jennifer E; Dudley, Timothy J

    2017-03-02

    Transition metal oxide cations (e.g., MO(+)) have been shown to oxidize small alkanes in the gas phase. The chromium oxide cation is of particular interest because it is more reactive than oxides of earlier transition metals but is more selective than oxides of later transition metals. The reaction of CrO(+) with propane has been shown to produce a number of products: propanol, propene, ethene, and hydrogen. Few theoretical studies exist for reactions of simple transition metal oxide cations with larger alkanes. We have analyzed the potential energy surfaces associated with the reaction of CrO(+) with propane using two DFT methods, B3LYP and M06-L. Energetically viable reaction paths leading to each experimentally observed product have been characterized. Each reaction path begins with formation of a reactive intermediate in which either an α- or β-hydrogen from propane is extracted by the oxygen atom of CrO(+). While pathways leading to formation of hydrogen and ethene were found to occur on a single spin surface, energetically viable pathways to forming propanol and propene require a transition from the quartet spin surface to the sextet surface. The minimum-energy crossing points between the quartet and sextet surfaces were found to be well below the energy level of the reactants and structurally resemble the initial reactive intermediates.

  12. Thermocatalytic Destruction of Gas-Phase Perchloroethylene Using Propane as a Hydrogen Source

    PubMed Central

    Willinger, Marty; Rupp, Erik; Barbaris, Brian; Gao, Song; Arnolda, Robert; Betterton, Eric; Sáez, A. Eduardo

    2009-01-01

    The use of propane in combination with oxygen to promote the destruction of perchloroethylene (PCE) over a platinum (Pt)/rhodium (Rh) catalyst on a cerium/zirconium oxide washcoat supported on an alumina monolith was explored. Conversions of PCE were measured in a continuous flow reactor with residence times less than 0.5 s and temperatures ranging from 200 to 600°C. The presence of propane was shown to increase significantly the conversion of PCE over oxygen-only conditions. Conversions close to 100% were observed at temperatures lower than 450°C with 20% oxygen and 2% propane in the feed, which makes this process attractive from a practical standpoint. In the absence of oxygen, PCE conversion is even higher, but the catalyst suffers significant deactivation in less than an hour. Even though results show that oxygen competes with reactants for active sites on the catalyst, the long-term stability that oxygen confers to the catalyst makes the process an efficient alternative to PCE oxidation. A Langmuir-Hinshelwood competitive adsorption model is proposed to quantify PCE conversion. PMID:19217713

  13. Kinetics of Hydrogen Oxidation Downstream of Lean Propane and Hydrogen Flames

    NASA Technical Reports Server (NTRS)

    Fine, Burton

    1961-01-01

    The decay of hydrogen was measured downstream of lean, flat, premixed hydrogen and propane-air flames seated on cooled porous burners. Experimental variables included temperature, pressure, initial equivalence ratio and diluent. Sampling of burned gas was done through uncooled quartz orifice probes, and the analysis was based on gas chromatography. An approximate treatment of the data in which diffusion was neglected led to the following rate expression for the zone downstream of hydrogen flames d[H (sub 2)] divided by (d times t) equals 1.7 times 10 (sup 10) [H (sub 2)] (sup 3) divided by (sub 2) [O (sub 2)]e (sup (-8100 divided by RT)) moles per liters per second. On the basis of a rate expression of this form, the specific rate constant for the reaction downstream of hydrogen flames was about three times as great as that determined downstream of propane flames. This result was explained on the basis of the existence of a steady state between hydrogen and carbon monoxide in the burned gas downstream of propane flames.

  14. Propanal synthesis from aqueous propylene glycol/hydrogen peroxide on a Ru/alumina catalyst

    SciTech Connect

    Disselkamp, Robert S.; Harris, Benjamin D.; Patel, Jayshribe N.; Hart, Todd R.; Peden, Charles HF

    2008-05-01

    The conversion of polyol materials, including 1,2-diols, into higher commodity chemicals is actively being pursued by many researchers. Here we report the production of propanal from propylene glycol and hydrogen peroxide using a Ru/alumina catalyst. Experiments were conducted by adding up to four peroxide equivalents under steady-state reflux conditions at 371 K. The product propanal and its subsequent reaction product with substrate, 1,3-dioxolane-2-ethyl-4-methyl, was observed to be an intermediate achieving a maximum concentration of 3% of substrate. Buffering using Mg(OH)2 at pH~10 resulted in propanal formation, whereas buffering at similar pH using Na2HSO4 did not, from which we propose that magnesium acts as a promoter in the reaction. The mechanism appears to be a dehydration to enol, followed by rearrangement to product. Experiments utilizing Ru/carbon did not yield any propanol suggesting that the acidic sites of alumina aid the dehydration reaction. To our knowledge, this represents the first time hydrogen peroxide has been used in an alcohol dehydration reaction.

  15. Sorption of methane, ethane, propane, butane, carbon dioxide, and nitrogen on kerogen

    NASA Astrophysics Data System (ADS)

    Pribylov, A. A.; Skibitskaya, N. A.; Zekel', L. A.

    2014-06-01

    Sorption isotherms of nitrogen, methane (in the pressure range of 0.1-40 MPa), ethane (0.1-3.7MPa), propane (0.01-1 MPa), butane (0.01-0.2 MPa), and carbon dioxide (0.1-6 MPa) are measured on two adsorbents with kerogen contents of 16 and 75% at temperatures of 303, 323, 343 K. Adsorption volumes are calculated for all adsorption systems using two independent methods. The BET technique is used to determine the surface area values of the two adsorbents on the basis of sorption data for ethane, propane, butane, and carbon dioxide. The initial and isosteric adheat of sorption values are calculated on the basis of sorption isotherms of ethane, propane, butane, carbon dioxide measured at three temperatures. It is found from comparing the dependences of isosteric heat of sorption on the two adsorbents that molecules of the above gases diffuse into its bulk (adsorbent 2) in addition to sorbing on the outside surface formed by kerogen molecules, while sorption of the same gases on the rock (adsorbent 1) is similar to sorption on a smooth hard adsorbent surface.

  16. Ethylene preparation and its application to physiological experiments.

    PubMed

    Zhang, Wei; Hu, Wenli; Wen, Chi-Kuang

    2010-04-01

    Ethylene is the first identified gaseous hormone regulating many aspects of plant growth and development. ACC and ethephon are two widely used chemicals replacing ethylene treatment when ethylene is not available. However, the amount of ethylene converted by ACC and ethephon is not controllable, leaving it questionable whether either treatment can mimic the effects of ethylene for experiments that are sensitive to ethylene concentration, response window, and treatment durations. Ethylene can be chemically made by ethanol dehydration; however, further purification from the dehydration products is needed. We previously reported that the ethylene gas can be easily prepared by decomposing ethephon in a buffered condition and the resulting ethylene can be used directly. Ethylene responses can be estimated by the measurement of the hypocotyl length of etiolated seedlings, or by ERF1 (Ethylene Response Factor1) expression. Although ACC of low concentrations is insufficient to induce ERF1 expression, ACC of high concentrations can replace ethylene for experiments where ethylene treatment is not feasible. However, ACC may undergo early consumption. Versatile approaches were developed so that laboratories lacking ethylene and techniques for gas handling can easily perform necessary ethylene treatments.

  17. A potential plant-derived antifungal acetylenic acid mediates its activity by interfering with fatty acid homeostasis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    6-Nonadecynoic acid (6-NDA), a plant-derived acetylenic acid, exhibits strong inhibitory activity against the human fungal pathogens Candida albicans, Aspergillus fumigatus, and Trichophyton mentagrophytes. In the present study, transcriptional profiling coupled with mutant and biochemical analyses...

  18. Numerical Study on the Acetylene Concentration in the Hydrogen-Carbon System in a Hydrogen Plasma Torch

    NASA Astrophysics Data System (ADS)

    Chen, Longwei; Shen, Jie; Shu, Xingsheng; Fang, Shidong; Zhang, Lipeng; Meng, Yuedong

    2009-06-01

    Effects of the hydrogen/carbon mole ratio and pyrolysis gas pressure on the acetylene concentration in the hydrogen-carbon system in a plasma torch were numerically calculated by using the chemical thermodynamic equilibrium method of Gibbs free energy. The calculated results indicate that the hydrogen concentration and the pyrolysis gas pressure play crucial roles in acetylene formation. Appropriately abundant hydrogen, with a mole ratio of hydrogen to carbon about 1 or 2, and a relatively high pyrolysis gas pressure can enhance the acetylene concentration. In the experiment, a compromised project consisting of an appropriate hydrogen flow rate and a feasible high pyrolysis gas pressure needs to be carried out to increase the acetylene concentration from coal pyrolysis in the hydrogen plasma torch.

  19. Tuning the C-H···π Interaction by Different Substitutions in Benzene-Acetylene Complexes.

    PubMed

    Mishra, Brijesh Kumar; Karthikeyan, S; Ramanathan, V

    2012-06-12

    The influence of substitutions in aromatic moieties on the binding strength of their complexes is a subject of broad importance. Using a set of various substituted benzenes, Sherrill and co-workers ( J. Am. Chem. Soc. 2011 , 133 , 13244 ; J. Phys. Chem. A 2003 , 107 , 8377 ) recently showed that the strength of a stacking interaction (π···π interaction) is enhanced by adding substituents regardless of their nature. Although the binding strength of an activated C-H···π interaction is comparable to that of a stacking interaction, a similar systematic study is hitherto unknown in the literature. We have computed the stabilization energies of the C-H···π complex of acetylene and multiple fluoro-/methyl-substituted benzenes at the coupled-cluster single and double (triple) excitation [CCSD(T)]/complete basis set (CBS) limit. The trend for interaction energies was found to be hexafluorobenzene-acetylene < sym-tetrafluorobenzene-acetylene < sym-trifluorobenzene-acetylene < sym-difluorobenzene-acetylene < benzene-acetylene < sym-dimethylbenzene-acetylene < sym-trimethylbenzene-acetylene < sym-tetramethylbenzene-acetylene < hexamethylbenzene-acetylene. Therefore, contrary to the case of stacking interaction ( Hohenstein et al. J. Am. Chem. Soc. 2011 , 133 , 13244 ), we show here that electron-withdrawing groups weaken the dimer while electron-donating groups strengthen the interaction energy of the dimer. Various recently developed density functional theoretic (DFT) methods were assessed for their performance and the M05-2X, M06-2X, and ωB97X-D methods were found to be the best performers. These best DFT performers were employed in determining the influence of other representative substituents (-NO2, -CN, -COOH, -Br, -Cl, -OH, and -NH2) as an extension to the above work. The results for the complex of acetylene and various para-disubstituted benzenes revealed a trend in binding energies that is in accordance with the ring-activating/deactivating capacity of

  20. The photolysis of NH3 in the presence of substituted acetylenes - A possible source of oligomers and HCN on Jupiter

    NASA Technical Reports Server (NTRS)

    Ferris, James P.; Jacobson, Richard R.; Guillemin, Jean C.

    1992-01-01

    An NMR spectral study is presently conducted of NH3 photolysis in the presence of substituted acetylenes with NMR spectra and gas chromatography. Quantum yields and percentage conversions to products are reported. It is shown that acetylenic hydrocarbons generated during methane photolysis in Jupiter's stratosphere can react with radicals formed by NH3 photolysis to yield nonvolatile, yellow-brown polymers, alkylnitriles, and in due course, HCN, as observed on Jupiter.

  1. Ethylene signaling and regulation in plant growth and stress responses.

    PubMed

    Wang, Feifei; Cui, Xiankui; Sun, Yue; Dong, Chun-Hai

    2013-07-01

    Gaseous phytohormone ethylene affects many aspects of plant growth and development. The ethylene signaling pathway starts when ethylene binds to its receptors. Since the cloning of the first ethylene receptor ETR1 from Arabidopsis, a large number of studies have steadily improved our understanding of the receptors and downstream components in ethylene signal transduction pathway. This article reviews the regulation of ethylene receptors, signal transduction, and the posttranscriptional modulation of downstream components. Functional roles and importance of the ethylene signaling components in plant growth and stress responses are also discussed. Cross-reactions of ethylene with auxin and other phytohormones in plant organ growth will be analyzed. The studies of ethylene signaling in plant growth, development, and stress responses in the past decade greatly advanced our knowledge of how plants respond to endogenous signals and environmental factors.

  2. Novel membrane technology for green ethylene production.

    SciTech Connect

    Balachandran, U.; Lee, T. H.; Dorris, S. E.; Udovich, C. A.; Scouten, C. G.; Marshall, C. L.

    2008-01-01

    Ethylene is currently produced by pyrolysis of ethane in the presence of steam. This reaction requires substantial energy input, and the equilibrium conversion is thermodynamically limited. The reaction also produces significant amounts of greenhouse gases (CO and CO{sub 2}) because of the direct contact between carbon and steam. Argonne has demonstrated a new way to make ethylene via ethane dehydrogenation using a dense hydrogen transport membrane (HTM) to drive the unfavorable equilibrium conversion. Preliminary experiments show that the new approach can produce ethylene yields well above existing pyrolysis technology and also significantly above the thermodynamic equilibrium limit, while completely eliminating the production of greenhouse gases. With Argonne's approach, a disk-type dense ceramic/metal composite (cermet) membrane is used to produce ethylene by dehydrogenation of ethane at 850 C. The gas-transport membrane reactor combines a reversible chemical reaction with selective separation of one product species and leads to increased reactant conversion to the desired product. In an experiment ethane was passed over one side of the HTM membrane and air over the other side. The hydrogen produced by the dehydrogenation of ethane was removed and transported through the HTM to the air side. The air provided the driving force required for the transport of hydrogen through the HTM. The reaction between transported hydrogen and oxygen in air can provide the energy needed for the dehydrogenation reaction. At 850 C and 1-atm pressure, equilibrium conversion of ethane normally limits the ethylene yield to 64%, but Argonne has shown that an ethylene yield of 69% with a selectivity of 88% can be obtained under the same conditions. Coking was not a problem in runs extending over several weeks. Further improved HTM materials will lower the temperature required for high conversion at a reasonable residence time, while the lower temperature will suppress unwanted side

  3. Portable Apparatus for Electrochemical Sensing of Ethylene

    NASA Technical Reports Server (NTRS)

    Manoukian, Mourad; Tempelman, Linda A.; Forchione, John; Krebs, W. Michael; Schmitt, Edwin W.

    2007-01-01

    A small, lightweight, portable apparatus based on an electrochemical sensing principle has been developed for monitoring low concentrations of ethylene in air. Ethylene has long been known to be produced by plants and to stimulate the growth and other aspects of the development of plants (including, notably, ripening of fruits and vegetables), even at concentrations as low as tens of parts per billion (ppb). The effects are magnified in plant-growth and -storage chambers wherein ethylene can accumulate. There is increasing recognition in agriculture and related industries that it is desirable to monitor and control ethylene concentrations in order to optimize the growth, storage, and ripening of plant products. Hence, there are numerous potential uses for the present apparatus in conjunction with equipment for controlling ethylene concentrations. The ethylene sensor is of a thick-film type with a design optimized for a low detection limit. The sensor includes a noble metal sensing electrode on a chip and a hydrated solid-electrolyte membrane that is held in contact with the chip. Also located on the sensor chip are a counter electrode and a reference electrode. The sensing electrode is held at a fixed potential versus the reference electrode. Detection takes place at active-triple-point areas where the sensing electrode, electrolyte, and sample gas meet. These areas are formed by cutting openings in the electrolyte membrane. The electrode current generated from electrochemical oxidation of ethylene at the active triple points is proportional to the concentration of ethylene. An additional film of the solid-electrolyte membrane material is deposited on the sensing electrode to increase the effective triple-point areas and thereby enhance the detection signal. The sensor chip is placed in a holder that is part of a polycarbonate housing. When fully assembled, the housing holds the solid-electrolyte membrane in contact with the chip (see figure). The housing includes

  4. Unexpected hydrodeiodo Sonogashira-Heck-Casser coupling reaction of 2,2'-diiodobiphenyls with acetylenes.

    PubMed

    Chou, Meng-Yen; Mandal, Ashis Baran; Leung, Man-kit

    2002-03-08

    2,2'-Diiodobiphenyl-4,4'-dicarboxylic acid dimethyl ester (3) undergoes either a ring-closure reaction with phenylacetylene to give 4 or hydrodeiodo phenylethynylation to give 5 under the catalytic conditions of Pd(OAc)(2)/CuI/phosphine in amines. In these reactions, the amine and the phosphine ligands play important roles in controlling the reactivity. Among the ligands we used, tris(o-tolyl)phosphine is the best ligand for hydrodeiodo phenylethynylation, while the bidentate phosphine ligand retards both of the reactions. On the basis of our results, we propose that 5 is formed through a fast hydrodeiodination, followed by a Sonogashira phenylethynylation. The results of the deuterium labeling experiments show that proton exchange between the acetylenic proton and the alkyl protons of amine occurs effectively under the reaction conditions. In addition, the hydrogen that replaces the iodide in the hydrodeiodination process arises mainly from the acetylenic proton.

  5. Acetylene/Vinylidene Isomerization after Carbon K-shell Photo-Ionization

    NASA Astrophysics Data System (ADS)

    Osipov, Timut; Weber, T.; Jahnke, T.; Alnaser, A.; Landers, A.; Hertlein, M.; Jagutzki, O.; Schmidt, L.; Schöffler, M.; Prior, M.; Feinberg, B.; Cocke, C. L.; Dörner, R.; Belkacem, A.

    2006-05-01

    Comprehensive study of the acetylene/vinylidene isomerization dynamics after the carbon k-shell photoionization followed by the Auger decay was performed by means of the COLTRIMS (COLd Target Recoil Ion Momentum Spectroscopy) technique. The Auger electrons, produced in this reaction, were detected in coincidence with the products of the Coulomb explosion of the dication C2H2^2+. Measurement of the 3d vector momenta for all detected particles inferred the Auger electron energies and directions in the body fixed molecular frame along with the KER (Kinetic Energy Release) for different break up channels. This highly differential reaction cross-section study provided very unique information about the fragmentation pathways of the doubly charged acetylene molecule.

  6. Isotope effect in normal-to-local transition of acetylene bending modes

    SciTech Connect

    Ma, Jianyi; Xu, Dingguo; Guo, Hua; Tyng, Vivian; Kellman, Michael E.

    2012-01-01

    The normal-to-local transition for the bending modes of acetylene is considered a prelude to its isomerization to vinylidene. Here, such a transition in fully deuterated acetylene is investigated using a full-dimensional quantum model. It is found that the local benders emerge at much lower energies and bending quantum numbers than in the hydrogen isotopomer HCCH. This is accompanied by a transition to a second kind of bending mode called counter-rotator, again at lower energies and quantum numbers than in HCCH. These transitions are also investigated using bifurcation analysis of two empirical spectroscopic fitting Hamiltonians for pure bending modes, which helps to understand the origin of the transitions semiclassically as branchings or bifurcations out of the trans and normal bend modes when the latter become dynamically unstable. The results of the quantum model and the empirical bifurcation analysis are in very good agreement.

  7. Unexpected chemistry from the reaction of naphthyl and acetylene at combustion-like temperatures.

    PubMed

    Parker, Dorian S N; Kaiser, Ralf I; Bandyopadhyay, Biswajit; Kostko, Oleg; Troy, Tyler P; Ahmed, Musahid

    2015-04-27

    The hydrogen abstraction/acetylene addition (HACA) mechanism has long been viewed as a key route to aromatic ring growth of polycyclic aromatic hydrocarbons (PAHs) in combustion systems. However, doubt has been drawn on the ubiquity of the mechanism by recent electronic structure calculations which predict that the HACA mechanism starting from the naphthyl radical preferentially forms acenaphthylene, thereby blocking cyclization to a third six-membered ring. Here, by probing the products formed in the reaction of 1- and 2-naphthyl radicals in excess acetylene under combustion-like conditions with the help of photoionization mass spectrometry, we provide experimental evidence that this reaction produces 1- and 2-ethynylnaphthalenes (C12 H8 ), acenaphthylene (C12 H8 ) and diethynylnaphthalenes (C14 H8 ). Importantly, neither phenanthrene nor anthracene (C14 H10 ) was found, which indicates that the HACA mechanism does not lead to cyclization of the third aromatic ring as expected but rather undergoes ethynyl substitution reactions instead.

  8. Isotope effect in normal-to-local transition of acetylene bending modes

    DOE PAGES

    Ma, Jianyi; Xu, Dingguo; Guo, Hua; ...

    2012-01-01

    The normal-to-local transition for the bending modes of acetylene is considered a prelude to its isomerization to vinylidene. Here, such a transition in fully deuterated acetylene is investigated using a full-dimensional quantum model. It is found that the local benders emerge at much lower energies and bending quantum numbers than in the hydrogen isotopomer HCCH. This is accompanied by a transition to a second kind of bending mode called counter-rotator, again at lower energies and quantum numbers than in HCCH. These transitions are also investigated using bifurcation analysis of two empirical spectroscopic fitting Hamiltonians for pure bending modes, which helpsmore » to understand the origin of the transitions semiclassically as branchings or bifurcations out of the trans and normal bend modes when the latter become dynamically unstable. The results of the quantum model and the empirical bifurcation analysis are in very good agreement.« less

  9. Modeling of acetylene pyrolysis under steel vacuum carburizing conditions in a tubular flow reactor.

    PubMed

    Khan, Rafi Ullah; Bajohr, Siegfried; Graf, Frank; Reimert, Rainer

    2007-03-02

    In the present work, the pyrolysis of acetylene was studied under steel vacuum carburizing conditions in a tubular flow reactor. The pyrolysis temperature ranged from 650 degrees C to 1050 degrees C. The partial pressure of acetylene in the feed mixture was 10 and 20 mbar, respectively, while the rest of the mixture consisted of nitrogen. The total pressure of the mixture was 1.6 bar. A kinetic mechanism which consists of seven species and nine reactions has been used in the commercial computational fluid dynamics (CFD) software Fluent. The species transport and reaction model of Fluent was used in the simulations. A comparison of simulated and experimental results is presented in this paper.

  10. Line intensity measurements for acetylene between 8980 and 9420 cm-1

    NASA Astrophysics Data System (ADS)

    Béguier, S.; Lyulin, O. M.; Hu, S.-M.; Campargue, A.

    2017-03-01

    The absorption spectrum of acetylene is studied by high-resolution Fourier-transform spectroscopy (FTS) between 8980 and 9420 cm-1. Positions and intensities of 432 12C2H2 absorption lines are retrieved from a spectrum recorded at room temperature (298.5 K) with a pressure of 87.6 hPa and a 105 m path length. The measured lines belong to 11 bands including three bands observed for the first time. The obtained intensity dataset constitutes the first intensity information in the region. The Herman-Wallis coefficients are derived from a fit of the measured intensity values. The reported results will be valuable to complete the spectroscopic databases of acetylene.

  11. Isotope effect in normal-to-local transition of acetylene bending modes.

    PubMed

    Ma, Jianyi; Xu, Dingguo; Guo, Hua; Tyng, Vivian; Kellman, Michael E

    2012-01-07

    The normal-to-local transition for the bending modes of acetylene is considered a prelude to its isomerization to vinylidene. Here, such a transition in fully deuterated acetylene is investigated using a full-dimensional quantum model. It is found that the local benders emerge at much lower energies and bending quantum numbers than in the hydrogen isotopomer HCCH. This is accompanied by a transition to a second kind of bending mode called counter-rotator, again at lower energies and quantum numbers than in HCCH. These transitions are also investigated using bifurcation analysis of two empirical spectroscopic fitting Hamiltonians for pure bending modes, which helps to understand the origin of the transitions semiclassically as branchings or bifurcations out of the trans- and cis-normal bend modes when the latter become dynamically unstable. The results of the quantum model and the empirical bifurcation analysis are in very good agreement.

  12. Characterization of the Minimum Energy Paths and Energetics for the reaction of Vinylidene with Acetylene

    NASA Technical Reports Server (NTRS)

    Walch, Stephen P.; Taylor, Peter R.

    1995-01-01

    The reaction of vinylidene (CH2C) with acetylene may be an initiating reaction in soot formation. We report minimum energy paths and accurate energetics for a pathway leading to vinylacetylene and for a number of isomers Of C4H4. The calculations use complete active space self-consistent field (CASSCF) derivative methods to characterize the stationary points and internally contacted configuration interaction (ICCI) and/or coupled cluster singles and doubles with a perturbational estimate of triple excitations (CCSD(T)) to determine the energetics. We find an entrance channel barrier of about 5 kcal/mol for the addition of vinylidene to acetylene, but no barriers above reactants for the reaction pathway leading to vinylacetylene.

  13. A study of the xenon effect in type-II clathrate hydrate synthesis; Commencing with hydrogen, argon and xenon uptake into a propane clathrate hydrate

    NASA Astrophysics Data System (ADS)

    Abbondondola, Joanne Angela

    It has been proposed that clathrate hydrates can be a possible storage medium for alternative fuels, such as hydrogen. The type-II propane gas hydrate is a viable choice because there are twice as many small cages as large cages and the small cavities are available for hydrogen storage. However, propane hydrate formation is a kinetically slow process which makes it commercially unattractive. Our objectives were twofold; (1) to quantify hydrogen, argon and xenon sorption into a preformed type-II propane hydrate at near-ambient conditions and (2) to investigate the effect of xenon on the rate of type-II propane hydrate formation. The propane hydrate is synthesized from 250 mum ice grains, and is estimated to have a porosity of 65 %. Hydrogen is rapidly absorbed by the hydrate sample and approaches the equilibrium vapor pressure in an hour before a very slow residual absorption process ensues. For an initial hydrogen pressure of 1.5 MPa, about 4.5 % of the available 512 cages are occupied by hydrogen after one hour, and 4.9 % after 18 hours. In contrast, for both argon and xenon significantly more gas is absorbed by the hydrate, but at a much slower rate: about 5% as fast for xenon and 1% as fast for argon. We conclude that hydrogen readily diffuses through the propane hydrate microcrystal structure, while argon and xenon are probably absorbed by growing new double hydrate while consuming the propane hydrate. Thus, although considerably higher pressures would be required to store significant quantities of hydrogen in propane hydrate, it appears that the crystal can be loaded and emptied in relatively short amounts of time. Experimental results show that propane is incorporated into clathrate hydrate cages more rapidly using propane-xenon mixtures than for pure propane gas. For a 0.92 xenon: propane mix, 60% of the theoretical yield of propane enclathration is achieved in 20 minutes, versus several days for pure propane. It appears that xenon serves to nucleate the

  14. Molecular mechanisms of ethylene signaling in Arabidopsis.

    PubMed

    Benavente, Larissa M; Alonso, Jose M

    2006-03-01

    Ethylene is a gaseous plant hormone involved in several important physiological processes throughout a plant's life cycle. Decades of scientific research devoted to deciphering how plants are able to sense and respond to this key molecule have culminated in the establishment of one of the best characterized signal transduction pathways in plants. The ethylene signaling pathway starts with the perception of this gaseous hormone by a family of membrane-anchored receptors followed by a Raf-like kinase CTR1 that is physically associated with the receptors and actively inhibits downstream components of the pathway. A major gap is represented by the mysterious plant protein EIN2 that genetically works downstream of CTR1 and upstream of the key transcription factor EIN3. Transcriptional regulation by EIN3 and EIN3-family members has emerged as a key aspect of ethylene responses. The major components of this transcriptional cascade have been characterized and the involvement of post-transcriptional control by ubiquitination has been determined. Nevertheless, many aspects of this pathway still remain unknown. Recent genomic studies aiming to provide a more comprehensive view of modulation of gene expression have further emphasized the ample role of ethylene in a myriad of cellular processes and particularly in its crosstalk with other important plant hormones. This review aims to serve as a guide to the main scientific discoveries that have shaped the field of ethylene biology in the recent years.

  15. Ethylene detection in fruit supply chains

    PubMed Central

    Janssen, S.; Schmitt, K.; Blanke, M.; Bauersfeld, M. L.; Wöllenstein, J.; Lang, W.

    2014-01-01

    Ethylene is a gaseous ripening phytohormone of fruits and plants. Presently, ethylene is primarily measured with stationary equipment in laboratories. Applying in situ measurement at the point of natural ethylene generation has been hampered by the lack of portable units designed to detect ethylene at necessary resolutions of a few parts per billion. Moreover, high humidity inside controlled atmosphere stores or containers complicates the realization of gas sensing systems that are sufficiently sensitive, reliable, robust and cost efficient. In particular, three measurement principles have shown promising potential for fruit supply chains and were used to develop independent mobile devices: non-dispersive infrared spectroscopy, miniaturized gas chromatography and electrochemical measurement. In this paper, the measurement systems for ethylene are compared with regard to the needs in fruit logistics; i.e. sensitivity, selectivity, long-term stability, facilitation of automated measurement and suitability for mobile application. Resolutions of 20–10 ppb can be achieved in mobile applications with state-of-the-art equipment, operating with the three methods described in the following. The prices of these systems are in a range below €10 000. PMID:24797138

  16. Ethylene and Metal Stress: Small Molecule, Big Impact

    PubMed Central

    Keunen, Els; Schellingen, Kerim; Vangronsveld, Jaco; Cuypers, Ann

    2016-01-01

    The phytohormone ethylene is known to mediate a diverse array of signaling processes during abiotic stress in plants. Whereas many reports have demonstrated enhanced ethylene production in metal-exposed plants, the underlying molecular mechanisms are only recently investigated. Increasing evidence supports a role for ethylene in the regulation of plant metal stress responses. Moreover, crosstalk appears to exist between ethylene and the cellular redox balance, nutrients and other phytohormones. This review highlights our current understanding of the key role ethylene plays during responses to metal exposure. Moreover, particular attention is paid to the integration of ethylene within the broad network of plant responses to metal stress. PMID:26870052

  17. Ozone-induced ethylene release from leaf surfaces

    SciTech Connect

    Rodecap, K.D.; Tingey, D.T.

    1986-01-01

    Ozone-induced stress-ethylene emissions from the adaxial and abaxial leaf surfaces of four plant species (Glycine max (L) Merr. cv. Dare, Lycopersicon esculentum Mill cv. Roma VF, Eucalyptus globulus Labill. and Hedera helix L.) were studied to determine if the stress ethylene diffused through the stomata or cuticle. In plants not exposed to ozone, basal ethylene was detected above both the adaxial and abaxial leaf surfaces of all the plant species examined, indicating that some ethylene can diffuse across the leaf cuticle. Oxone-induced stress ethylene production in all species examined. These data indicate that ozone-induced stress ethylene primarily diffuses from the leaf via the stomata.

  18. Laser-induced fluorescence study of the S1 state of doubly-substituted 13C acetylene and harmonic force field determination.

    PubMed

    Jiang, Jun; Baraban, Joshua H; Park, G Barratt; Clark, Michelle L; Field, Robert W

    2013-12-19

    In the first half of this study, rotational and vibrational constants of six Franck-Condon bright vibrational levels of S1 doubly-substituted (13)C acetylene are determined from laser-induced fluorescence spectra and an updated geometry of the trans conformer of S1 acetylene is obtained. In the second half, we determine the quadratic force field of S1 acetylene on the basis of the harmonic frequencies of four isotopologues of acetylene. The effects of both diagonal and off-diagonal x(ij) anharmonicities are removed from the input harmonic frequencies. Results from both experimental and theoretical studies of various isotopologues of acetylene (including those from the first half of this paper) are used to obtain a set of force constants that agrees well with ab initio calculations. Our set of force constants for S1 acetylene is an improvement over previous work by Tobiason et al., which did not include off-diagonal anharmonicities.

  19. Theoretical study of the C-H bond dissociation energy of acetylene

    NASA Technical Reports Server (NTRS)

    Taylor, Peter R.; Bauschlicher, Charles W., Jr.; Langhoff, Stephen R.

    1990-01-01

    The authors present a theoretical study of the convergence of the C-H bond dissociation energy (D sub o) of acetylene with respect to both the one- and n-particle spaces. Their best estimate for D sub o of 130.1 plus or minus 1.0 kcal/mole is slightly below previous theoretical estimates, but substantially above the value determined using Stark anticrossing spectroscopy that is asserted to be an upper bound.

  20. FAST TRACK COMMUNICATION: Fragmentation pathways for selected electronic states of the acetylene dication

    NASA Astrophysics Data System (ADS)

    Osipov, T.; Rescigno, T. N.; Weber, T.; Miyabe, S.; Jahnke, T.; Alnaser, A. S.; Hertlein, M. P.; Jagutzki, O.; Schmidt, L. Ph H.; Schöffler, M.; Foucar, L.; Schössler, S.; Havermeier, T.; Odenweller, M.; Voss, S.; Feinberg, B.; Landers, A. L.; Prior, M. H.; Dörner, R.; Cocke, C. L.; Belkacem, A.

    2008-05-01

    Coincident measurement of the Auger electron and fragment ion momenta emitted after carbon core-level photoionization of acetylene has yielded new understanding of how the dication fragments. Ab initio calculations and experimental data, including body-frame Auger angular distributions, are used to identify the parent electronic states and together yield a comprehensive map of the dissociation pathways which include surface crossings and barriers to direct dissociation. The Auger angular distributions for certain breakup channels show evidence of core-hole localization.