25067-58-7Relevant articles and documents
Thermal decomposition of quinoline and isoquinoline. The role of 1-indene imine radical
Laskin, Alexander,Lifshitz, Assa
, p. 928 - 946 (1998)
The thermal reactions of quinoline and isoquinoline were studied behind reflected shock waves in a pressurized driver single pulse shock tube over the temperature range 1275-1700 K and densities of ～3 ×10-5 mol/ cm3. The decomposition products found in the postshock mixtures of quinoline and isoquinoline and their production rates were identical for both isomers. They were C2H2, C6H5CN, HC≡CCN, C6H6, HCN, C6H5-C≡CH and C4H2. Trace quantities of C6H4, C5H5N and C5H4N-C≡CH were also found. The total disappearance rates of quinoline and isoquinoline are the same, and in terms of a first-order rate constant they are given by ktotal = 1013.0exp(-75.5 × 103/RT) s-1 where R is expressed in units of cal/(K mol). The same product distribution in the two isomers can be accounted for if the production of 1-indene imine radical as an intermediate is assumed. A kinetic scheme containing the reactions of both quinoline and isoquinoline with 72 species and 148 elementary reactions accounts for the observed product distribution. The reaction scheme is given, and the results of computer simulation and sensitivity analysis are shown.
Reactions of tetraethoxysilane vapor on polycrystalline titanium dioxide
Jurgens,Rogers Jr.
, p. 731 - 743 (1995)
The reactions of tetraethoxysilane (TEOS) vapor on dehydroxylated and water predosed polycrystalline TiO2 were studied by Fourier transform infrared spectroscopy (FTIR) and temperature-programmed desorption (TPD). Exposure at 300 K leads to dissociative adsorption producing a monoethoxysilyl ligand and surface ethoxide species. The ethoxide ligands react and desorb in the range 450-650 K as gas phase ethanol and ethylene, while the monoethoxysilyl ligand decomposes at approximately 650 K to gas phase ethanol and ethylene and surface bound SiO2. Dissociation of TEOS on TiO2 is not affected by water predose; although, a greater amount of ethanol is produced in the gas phase at 550-650 K, and the SiO2 which is formed exhibits vibrational features characteristic of a hydroxylated species. TEOS chemistry on TiO2 was compared to the adsorption and reaction of ethanol on the same surface. Adsorption of ethanol at 300 K yielded surface ethoxide species which desorbed in two states as the parent alcohol and ethylene; desorption was also centered at 450 and 650 K. These results complement and supplement our previous study of TEOS on a TiO2(110) single crystal surface.
Excellent effect of lithium-doped sulfated zirconia catalysts for oxidative coupling of methane to give ethene and ethane
Murata, Kazuhisa,Hayakawa, Takashi,Fujita, Ken-Ichi
, p. 221 - 222 (1997)
Li-doped sulfated zirconia catalysts are found to be effective for oxidative coupling of methane; ca. 80% C2 selectivity is attained at 1073 K with 43% CH4 conversion.
The high-resolution infrared spectrum of diacetylene and structures of diacetylene, triacetylene and dicyanoacetylene
McNaughton, D.,Bruget, D. N.
, p. 11 - 26 (1992)
The ν6 and ν8 combination band of diacetylene has been remeasured at 0.0019 cm-1 resolution with a Fourier transform infrared spectrometer.Analysis and assignment of the improved data sets were carried out with an interactive Loomis-Wood fitting program.Altogether more than 1400 assignments were made and band origins, rotational and distortion constants for the main band and associated hot bands were determined.The band centre was found to be 1241.060828(37) cm-1 and the ground-state rotational and distortion constants, B0 and D0, were found to be 0.14641021(52) cm-1 and 1.6085(49)*10-8 cm-1, respectively.The experimental values of B0 for diacetylene, triacetylene and dicyanoacetylene are compared with values predicted from ab initio calculations, and with values obtained from estimates derived from the known structural parameters of HC3N and HC5N.Several very weak difference bands, 110901, 110801 and 410601, and combination bands, 510610 and 110910 in the region 3600-2600 cm-1 were also assigned.
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Barker
, p. 631 (1953)
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Main Gaseous Products of Microwave Discharge in Various Liquid Hydrocarbons
Averin,Lebedev, Yu. A.,Tatarinov
, p. 331 - 335 (2019)
Abstract: Main gaseous products (H2, C2H2, C2H4, CH4) formed by microwave discharge in a number of liquid alkanes, cycloalkanes, and aromatic hydrocarbons have been studied using gas chromatography. It has been shown that the products of the discharge in these cycloalkanes and aromatic compounds bearing no side groups almost do not contain methane or ethylene, unlike the case of alkanes.
Efficient Conversion of CO + H2 into Acetylene at Atmospheric Pressure using a Graphite-based Catalyst
Jones, William,Schloegl, Robert,Thomas, John M.
, p. 464 - 466 (1984)
A 3 : 1 mixture of H2 : CO (total pressure 1 atm) is converted with ca. 20percent efficiency and ca. 95percent selectivity into acetylene at 100 deg C over a catalyst generated by partially de-intercalating a (first stage) sandwich compound C9FeCl3 with potassium naphthalenide: the catalyst maintains its performance for several days under these conditions.
THE MATRIX PHOTOLYSIS OF PYRIDINE-2,3- AND -3,4-DICARBOXYLIC ANHYDRIDES
Dunkin, Ian R.,MacDonald, J. Gavin
, p. 4839 - 4842 (1982)
Photolysis of anhydrides (1) and (5) in low temperature matrices led to loss of CO and CO2 in each case, but pyridynes were not detected, and if formed at all, underwent immediate further bond fission.
Reactions of Carbon Atoms/Clusters with Methane, Methyl Bromide, and Water at 10 and 77 K
Jeong, Gi Ho,Klabunde, Kenneth J.,Pan, Ohm-Guo,Paul, G. C.,Shevlin, Philip B.
, p. 8784 - 8790 (1989)
The reactions of C atoms, C2, and C3 were monitored under matrix isolation conditions (10 K, argon) with methane, methyl bromide, and water.With CH4 + C, the singlet state (1D) reacted by C-H insertion followed by rearrangement to ethylene.Ground-state 3P atoms did not react, although C2 reacted but products could not be spectroscopically determined.Trimer C3 and higher clusters did not react with CH4.With CH3Br, C, C2, C3 and higher clusters all reacted.The main product with C atoms was the stabilized carbene CH3CBr formed by C-Br insertion.With H2O, a majorproduct was CO formed from 1S and/or 1D carbon atoms.Carbon clusters also reacted, but less efficiently than with CH3Br.In order to determine the nature of the isolable products when carbon vapor reacted with methane, carbon arc experiments and 5-diazotetrazole decomposition experiments were carried out at 77 K.Isotope labeling and product analyses showed that C1 reacted both by C-H insertion and hydrogen abstraction, and one mode for acetylene formation may be dimerization of CH.Vapor components C2 and C3 react with methane by hydrogen abstraction processes at 77K.
KrF Laser-induced Thermal Decomposition of 1,2-Dichloroethane
Dyer, Peter E.,Matthews, Martin,Holbrock, Kenneth A.,Oldershaw, Geoffrey A.
, p. 2151 - 2156 (1991)
The thermal decomposition of 1,2-dichloroethane to give vinyl chloride and hydrogen chloride has been reinvestigated at 703 K and the major features of this free-radical chain reaction found previously have been confirmed.A direct comparison of the pulsed KrF laser-induced process (248 nm) in the same static reactor at this temperature showed that a substantial increase in rate occurs even at low pulse-repetition rates (2 Hz).In an extended study of the laser-induced reaction at temperature where thermal reaction is negligible (476-577 K), quantum yields of vinyl chloride formation have been measured to be between 3000 and 13 000.Quantum yields decreased slighthly with increasing pressure and showed an inverse square-root dependence on initial chlorine atom concentration.The major by-products were identified as ethene, ethyne, 1,2,3,4-tetrachlorobutane and 1,1,2-trichloroethane.At 577 K and 150 Torr, the quantum yield of ethene production is close to unity, indicating that under these conditions reaction (2) is essentially complete. C2H4Cl2 + hν (248 nm) --> CH2ClCH2* + Cl (1) CH2ClCH2* --> C2H4 + Cl (2) Computer modelling of a complete reaction mechanism involving the propagation steps (3) and (4) Cl + C2H4Cl2 --> C2H3Cl2 + HCl (3) C2H3Cl2 --> C2H3Cl + Cl (4) was used to predict quantum yields of both vinyl chloride and the minor products.
Wilkinson, J. A.
, p. 237 - 237 (1931)
Surface Coversion of Benzene to Acetylene
Parker, W. L.,Hexter, R. M.,Siedle, A. R.
, p. 4584 - 4585 (1985)
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Selective hydrogenation of acetylene in the presence of ethylene on zeolite-supported bimetallic catalysts
Huang, Wei,McCormick, John R.,Lobo, Raul F.,Chen, Jingguang G.
, p. 40 - 51 (2007)
Novel catalysts were synthesized by supporting Pd-based bimetallic catalysts on Na+-exchanged β-zeolites to achieve higher selectivity for the hydrogenation of acetylene in the presence of ethylene at room temperature. Batch reactor studies carried out using infrared spectroscopy show that Pd-Ag bimetallic catalysts have higher selectivity for acetylene hydrogenation in the presence of ethylene than either Pd or Ag monometallic catalysts. Kinetic modeling of the reaction data reveals significant differences in the hydrogenation rate constants and adsorption equilibrium constants. The influence of the Na+-β-zeolite support is compared with traditional γ-Al2O3-supported catalysts. The Na+-β-zeolite-supported catalysts exhibit higher selectivity than their γ-Al2O3 counterparts. Overall, zeolite-supported Pd-Ag bimetallic catalyst was found to have the highest selectivity of the catalysts studied.
Kinetics of the Reactions of C2H with C2H2, H2, and D2
Koshi, Mitsuo,Nishida, Nobuhiro,Matsui, Hiroyuki
, p. 5875 - 5880 (1992)
Kinetics of the reactions C2H + C2H2 --> C4H2 + H (1), C2H + H2 --> C2H2 + H (2), and C2H + D2 --> C2HD + D (3) have been studied at T = 293 K with two time-resolved diagnostics, laser-induced fluorescence (LIF) detection of H (or D) atoms at the Lyman-α wavelength and mass spectrometric detection of C4H2.The C2H radical was prepared by the ArF (193 nm) laser photolysis of C2H2.Measurements of the yield of H (or D) atom indicated that the C2H radicals produced by the photolysis were converted effectively to H (or D) atoms; i.e. formation of the stable intermediatessuch as C4H3, C2H3, or C2HD2 was negligible under the present experimental conditions (p = 30 Torr).Rate constants of k1 = (1.6 +/- 0.1) * 10-10, k2 = (7.1 +/- 1.1) * 10-13, and k3 = (2.0 +/- 0.3) * 10-13 cm3 molecule-1 s-1 were derived from the pseudo-first-order rise rates of the H (or D) atom.Rate constant of k1 = (1.4 +/- 0.3) * 10-10 cm3 molecule-1 s-1 was also obtained at p = 5 Torr by measuring the appearance rate of C4H2.The ratios of the rate constants k2/k1 = (3.4 +/- 0.2) * 10-3 and k3/k1 = (1.4 +/- 0.5) * 10-3 were deduced by measuring the dependence of the C4H2 production on the partial pressure of added H2 or D2.Transition state theory calculations on the basis of ab initio transition-state properties demonstrated the importance of the tunnel effect for reaction 2 at room temperature.
Porous clay heterostructures (PCH) as acid catalysts
Galarneau, Anne,Barodawalla, Anis,Pinnavaia, Thomas J.
, p. 1661 - 1662 (1997)
Porous clay heterostructures formed by surfactant assembly of open framework silica in the galleries of a smectite clay represent a new family of solid acid catalysts, as evidenced by the selective dehydration of 2-methylbut-3-yn-2-ol to 2-methylbut-3-yn-1-ene.
Isotope Effects in Plasmonic Photosynthesis
Jain, Prashant K.,Yu, Sungju
, p. 22480 - 22483 (2020)
The photoexcitation of plasmonic nanoparticles has been shown to drive multistep, multicarrier transformations, such as the conversion of CO2 into hydrocarbons. But for such plasmon-driven chemistry to be precisely understood and modeled, the critical photoinitiation step in the reaction cascade must be identified. We meet this goal by measuring H/D and 12C/13C kinetic isotope effects (KIEs) in plasmonic photosynthesis. In particular, we found that the substitution of H2O with D2O slows hydrocarbon production by a factor of 5–8. This primary H/D KIE leads to the inference that hole-driven scission of the O?H bond in H2O is a critical, limiting step in plasmonic photosynthesis. This study advances mechanistic understanding of light-driven chemical reactions on plasmonic nanoparticles.
H-atom yields from the photolysis of acetylene and from the reaction of C2H with H2, C2H2, and C 2H4
Kovacs, Tamas,Blitz, Mark A.,Seakins, Paul W.
, p. 4735 - 4741 (2010)
The photolysis of acetylene at 193 nm has been investigated as a source of the ethynyl radical, C2H, for product branching ratio studies, particularly the formation of H atom product as the photolysis, producing a 1:1 ratio of C2H and H, provides an internal calibration. Previous literature had suggested that C2H and H may only be a minor component of acetylene photolysis at 193 nm. Acetylene was photolyzed at low laser energy densities (-2), with H atoms being observed as a function of time by VUV laser induced fluorescence. When C2H was reacted with C2H 2, a reaction that is known to produce H atoms with unit yield, the ratio of photolytic H atom production to chemical production was 0.96 (0.03. The rate coefficient for the reaction of C2H with C2H 2 could accurately be retrieved from the time evolution of the H atom signal. The results suggest that acetylene photolysis at low laser energies is a good source of C2H for product branching studies, and the technique has been applied to the reactions of C2H with ethene and propene. For the reaction with ethene between 23 and 81 Torr, the yield of H is 0.94 (0.06, suggesting that an addition eliminationmechanism dominates with the formation of vinylacetylene and H atoms. For the reaction of C2H with propene, no H atom product was observed, putting a lower limit of 5% for H atom production. Possible explanations for the low H atom yield are discussed. The implications of these results in combustion and planetary atmospheres are briefly considered. Copyright
Direct synthesis of acetylene from methane by direct current pulse discharge
Kado, Shigeru,Sekine, Yasushi,Fujimoto, Kaoru
, p. 2485 - 2486 (1999)
In non-catalytic direct conversion of methane to acetylene by using direct current pulse discharge under conditions of ambient temperature and atmospheric pressure, the selectivity of acetylene from methane was >95% at methane conversion ranging from 16 to 52%; coexisting oxygen was very effective in removing deposited carbon and stabilized the state of discharge.
Direct conversion of methane over oxide-type catalysts supported on mesoporous silica under electric discharge
Kim, Taegyu,Park, Daeil
, p. 2567 - 2570 (2017)
Direct conversion of methane over oxide-type catalysts supported on mesoporous material under the dielectric barrier discharge plasma was investigated in the present study. The oxide catalysts (MgO and NiO) supported on SBA-15 was prepared by a hydrothermal and wet-impregnation method. The low-angle XRD patterns and TEM indicate that the ordered mesoporous structure was well maintained during the catalyst preparation and reaction processes. We also conducted direct conversion of methane using the catalysts under the plasma. As a result, the specific surface area of bare SBA-15 was much higher than that of the NiO/SBA-15, followed by MgO/SBA-15. Overall, the CH4 conversion increased with increasing the specific surface area. And C2 selectivity decreased with increasing the specific surface area.
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Zechmeister,Magoon
, p. 2149 (1956)
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INTEGRAL CARBON MASS BALANCE IN PREMIXED SOOTING FLAMES.
Brei,Jander,Wagner
, p. 30 - 36 (1987)
In sooting C//2H//4-air, C//6H//6-air and C//2H//2-air flames the burned gases have been analyzed for different fuel-air ratios and the fractions of carbon which end up as CO and CO//2, as soot and as hydrocarbons have been determined. The amount of soot formed increases strongly with increasing fuel content beyond the threshold of soot formation, following approximately the same formal relation for the different fuels. At a given fuel concentration above the soot threshold the soot mass per cm**3 rises from C//2H//2 to C//2H//4 and to C//6H//6-air flames. The concentrations of hydrocarbons in the burned gases increase also with increasing fuel concentrations but in different ways for the different fuels. For benzene-air flames the carbon present as soot exceeds that present as hydrocarbon already at fuel concentrations slightly above the soot threshold.
Reaction of a stable digermyne with acetylenes: Synthesis of a 1,2-digermabenzene and a 1,4-digermabarrelene#
Sugahara, Tomohiro,Guo, Jing-Dong,Sasamori, Takahiro,Karatsu, Yusaku,Furukawa, Yukio,Ferao, Arturo Espinosa,Nagase, Shigeru,Tokitoh, Norihiro
, p. 1375 - 1384 (2016)
Reactions between acetylenes and a stable digermyne bearing 4-t-Bu-2,6-[CH(SiMe3)2]2-C6H2 (Tbb) groups afforded the corresponding stable 1,2-digermabenzenes together with the respective 1,4-digermabarrelenes. The properties of the obtained products and the reaction mechanism are discussed on the basis of experimental and theoretical results. Especially, the aromaticity of the newly obtained 1,2-digermabenzene has been discussed on the detailed calculations, revealing its aromatic character to some degree.
Dynamics of ethylene photodissociation from rovibrational and translational energy distributions of H2 products
Cromwell, Evan F.,Stolow, Albert,Vrakking, Marcus J. J.,Lee, Yuan T.
, p. 4029 - 4040 (1992)
The dynamics of H2 elimination from ethylene was studied via a pump and probe technique utilizing an ultrahigh resolution vacuum ultraviolet laser system.H2 product internal and translational energy distributions were obtained for the photodissociation at 193 nm.The distribution of energy in H2 product from the dissociation of (1,1)-dideuteroethylene is also presented.Two separate H2 elimination channels are inferred: a 1,1 elimination producing the vinylidene radical and a 1,2 elimination producing the acetylene molecule.Differences between the vibrational, rotational, and translational energy distributions for these two channels are discussed and correlations between product internal and translational energy are presented.A comparison with ab initio calculations of the transition state configurations for these process is made.We suggest that the H2 elimination process may be nonstatistical in nature.The D atom elimination from C2D4 was examined and kinetic energy distribution for this product measured.
KINETICS OF THE REACTION Cl+C2H4C2H3+HCl. HEAT OF FORMATION OF THE VINYL RADICAL
Parmar, Sucha S.,Benson, Sidney W.
, p. 2652 - 2657 (1988)
The bimolecular rate constant for the title reaction has been measured by using the very low pressure reactor technique at 2631=(5.66+/-0.7)*1E-13 cm3/(molecule s) and from the range of temperature measurements log k1(cm3/(molecule s))=-(10.50+/-0.2)-(2.8+/-0.4)/θ where θ=2.303RT (kcal/mol).In addition, the ratio k1/k-1 was also measured over this temperature range.The value of K1 at room temperature was found to be 1.10+/-0.16.From the Van't Hoff plot of ln K1 versus 1/T the values of heat of formation of the vinyl radical and C-H bond strength in ethylene are 66.7+/-0.5 and 106.3+/-0.4 kcal/mol, respectively.From more reliable third-law calculations at 293 K, ΔHfo(C2H3)=66.2+/-0.4 kcal/mol and DHo(C2H3-H)=105.8+/-0.4 kcal/mol.Transition-state (TS) models of the reaction rule out a linear TS in favor a bent TS.The TS A factor was estimated to be 1010.60L/(mol s), in fair agreement with the experimental value of 1010.50L/(mol s).
Influence of low-voltage discharge energy on the morphology of carbon nanostructures in induced benzene transformation
Bodrikov, Ivan Vasilievich,Ivanova, Anna Gennadevna,Serov, Anton Igorevich,Titov, Dmitry Yurievich,Titov, Evgeny Yurievich,Vasiliev, Alexander Leonidovich
, p. 39428 - 39437 (2021/12/24)
The directions of the transformation of benzene induced by low-voltage discharges at various energies of pulsed discharges were revealed. This paper shows the dependencies of the morphology and other characteristics of nanostructures obtained in the induced transformation of benzene on the energy of pulsed discharges. Nanostructures with different morphologies are formed when the energy of the low-voltage discharges changes during the induced transformation of benzene in the liquid phase. Two types of carbon nanostructures were formed in the induced destruction of benzene with a 90 μF capacitor. The first type of structure includes graphite fibers, two- and three-layer graphene sheets, as well as two- and three-layer hollow spheres and microstructures in the form of CNHs. The microstructures of the second type were onion-like spheroids. An increase in the capacitance up to 20?090 μF led to the formation of two types of nanostructures: onion-like spheroids and carbon fibers. A further increase in the capacitance to 40?090 μF caused the formation of onion-like spheroids.
Direct Evidence on the Mechanism of Methane Conversion under Non-oxidative Conditions over Iron-modified Silica: The Role of Propargyl Radicals Unveiled
?ot, Petr,Hemberger, Patrick,Pan, Zeyou,Paunovi?, Vladimir,Puente-Urbina, Allen,van Bokhoven, Jeroen Anton
supporting information, p. 24002 - 24007 (2021/10/01)
Radical-mediated gas-phase reactions play an important role in the conversion of methane under non-oxidative conditions into olefins and aromatics over iron-modified silica catalysts. Herein, we use operando photoelectron photoion coincidence spectroscopy to disentangle the elusive C2+ radical intermediates participating in the complex gas-phase reaction network. Our experiments pinpoint different C2-C5 radical species that allow for a stepwise growth of the hydrocarbon chains. Propargyl radicals (H2C?C≡C?H) are identified as essential precursors for the formation of aromatics, which then contribute to the formation of heavier hydrocarbon products via hydrogen abstraction–acetylene addition routes (HACA mechanism). These results provide comprehensive mechanistic insights that are relevant for the development of methane valorization processes.
SYSTEMS AND METHODS FOR PROCESSING GASES
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Paragraph 00107-00111; 00118-00121, (2020/03/15)
The invention includes a gas processing system for transforming a hydrocarbon- containing inflow gas into outflow gas products, where the system includes a gas delivery subsystem, a plasma reaction chamber, and a microwave subsystem, with the gas delivery subsystem in fluid communication with the plasma reaction chamber, so that the gas delivery subsystem directs the hydrocarbon-containing inflow gas into the plasma reaction chamber, and the microwave subsystem directs microwave energy into the plasma reaction chamber to energize the hydrocarbon-containing inflow gas, thereby forming a plasma in the plasma reaction chamber, which plasma effects the transformation of a hydrocarbon in the hydrocarbon-containing inflow gas into the outflow gas products, which comprise acetylene and hydrogen. The invention also includes methods for the use of the gas processing system.
