1070-71-9Relevant articles and documents
Pyrolysis of Acrylonitrile at Elevated Temperatures. Studies with a Single-Pulse Shock Tube
Lifshitz, Assa,Bidani, Menashe,Suslensky, Aya,Tamburu, Carmen
, p. 1369 - 1373 (1989)
The thermal decomposition of acrylonitrile was studied behind reflected shocks in a single-pulse shock tube over the temperature range 1150-1430 K and overall densities of ca. 3 X 10-5 mol/cm3.Under these conditions the major reaction products are (1) hydrogen cyanide and acetylene and (2) hydrogen and cyanoacetylene: CH2=CHCN -> CH*CH + HCN (reaction 1) and CH2=CHCN -> CH*C-CN + H2 (reaction 7).In the presence of toluene, at a ratio of 0/0 ca. 10/1, a twofold decrease in the production rate of these products was observed, indicating a free-radical mechanism in parallel to the four-center eliminations.After the contribution of the free radical chain was subtracted, the following rate constants for the four-center eliminations were obtained: k1 = 1012.25 exp (-68 X 103/RT) s-1, and k2 = 1013.40 exp (-77 X 103/RT) s-1, where activation energies are expressed in units cal/mol.Ethylene was found in quantities roughly equal to those of cyanoacetylene.C2N2, CH3CN, CH4, C4H6 and C2H6 were found in the postshock mixtures but at much lower concentrations.Arrhenius parameters for the formation rate of the different reaction products are given and the general pyrolysis mechanism is discussed.
The pyrolysis of 3-picoline: Ab initio quantum chemical and experimental (shock tube) kinetic studies
Jones, Jeffrey,Bacskay, George B.,Mackie, John C.
, p. 239 - 248 (1996)
The pyrolysis of 3-picoline dilute in argon was investigated using a single-pulse shock tube over the temperature range of 1400-1650 K and total pressures of 12-13 atm. The principal products observed were HCN, acetylene, benzene, cyanoacetylene, methane, and pyridine. Assuming that 3-picoline decomposes according to first-order kinetics, the rate constant for its overall disappearance was determined to be kdis = 1016.9(±0.8) exp[-99 (±6) kcal mol-1/RT] s-1. The principal initial decomposition routes were found to be via the formation of the 3-picolyl and m-pyridyl radicals whose subsequent ring-opening led to the observed products. A 68-step kinetic model was developed that successfully fits the experimental data. The dominant reactions, i.e., the formation of picolyl and pyridlyl radicals and their subsequent chain-opening reactions, were studied using ab initio quantum chemical techniques. The ab initio data were also incorporated into the kinetic model in the form of energies and A-factors for reactions for which no kinetic or thermochemical data were previously available. Optimization of the kinetic model yields a value of 64 ± (3) kcal mol-1 for the heat of formation of 3-picolyl, a value lower than that for 2-picolyl, suggesting that the decomposition of 3-picoline more closely resembles that of toluene, rather than its isomer 2-picoline.
First Direct Observation of Pyridyne: Matrix Infrared Study of the Photolysis Products of 3,4-Pyridine Dicarboxylic Anhydride
Nam, H.-H.,Leroi, G. E.
, p. 4096 - 4097 (1988)
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Kinetics of Thermal Decomposition of the Diazines: Shock-tube Pyrolysis of Pyrimidine
Doughty, Alan,Mackie, John C.
, p. 541 - 548 (1994)
The kinetics of pyrolysis of pyrimidine diluted in argon have been studied behind reflected shock waves over the temperature range 1200-1850 K, at uniform gas residence times of 850-1000 μs and pressures of 13-15 atm.The major products of pyrimidine pyrolysis were found to be acetylene, HCN, acrylonitrile, cyanoacetylene and H2.Using both end-product analysis and real-time UV spectrometry the kinetics of pyrimidine disappearance were found to be first order with respect to reactant concentration over the concentration range of 0.07-0.3 molpercent.The two techniques yielded a first-order rate constant (kdis) for the disappearance of pyrimidine given by the expression 1012.3(+/-0.4)exp-1/RT>s-1.A detailed reaction model incorporating a free-radical mechanism for the decomposition of pyrimidine has been developed, and shown to predict the reactant and product concentrations between 1250 and 1600 K.Important radicals in the mechanism were found to be o- and p-pyrimidyl, with H atoms and CN radicals being radical chain carriers.Sensitivity and flux analysis of the kinetic model has shown the most important initiation pathway to be the loss of an H atom from pyrimidine to yield o-pyrimidyl.Optimisation of the Arrhenius parameters for this initiation reaction yields an activation energy cosistent with a heat of formation of the o-pyrimidyl radical of 376(+/-10) kJ mol-1.
Photochemistry of Acetylene, Hudrogen Cyanide, and Mixtures
Becker, Ralph S.,Hong, J. H.
, p. 163 - 166 (1983)
Photoluses of HCN, C2H2, and mixtures were accomplished including various ratios of HCN/C2H2 and time periods.The photolysis of HCN yielded (CN)2, CH4, NH3, CH3NH2, (NH)2, and a brown polymer.The products from C2H2 were diacetylene (C4H2), C2H4, C6H6, vinylacetylene, phenylacetylene, and a polymer.Products from a relatively low HCN/C2H2 ratio (5:1) where 90percent of the light is absorbed by C2H2 were similar to those of C2H2 except for the additional formation of acrylonitrile (C2H3CN).At relatively higher ratios of HCN/C2H2 where 37-56percent of the light is absorbed by HCN, cyanoacetylene (C2HCN) was formed in addition to the foregoing products and the C4H2 substantially reduced.The proposed principal path for formation of C4H2 is attack of C2H. on C2H2, while for C2H3CN the principal path is attack of C2H3. on HCN.The proposed principal path for production of C2HCN is via CN. attack on C2H2.Several products from HCN are proposed to be the result of progressive H atom addition.Other products from C2H2 and HCN are the result of radical-radical recombination.We believe these results could have relevance to Jovian atmosphere chemistry and formation of several molecules found in interstellar space.
Kinetics of Pyrolysis of a Coal Model Compound, 2-Picoline, the Nitrogen Heteroaromatic Analogue of Toluene. 1. Product Distributions
Terentis, Andrew,Doughty, Alan,Mackie, John C.
, p. 10334 - 10339 (1992)
The pyrolysis of 2-picoline in dilute mixtures with argon has been investigated using the single-pulse shock tube and was found to decompose over the temperature range 1300-1550 K, at an average residence time of 800 μs and uniform pressure of 14-16 atm.The major products observed were acetylene, methane, hydrogen, HCN, and cyanoacetylene.Over the studied range of mixture compositions (0.06-0.20 molpercent of 2-picoline) the overall rate of disappearance of 2-picoline obeyed first-order kinetics.Arrhenius parameters for disappearance of picoline were found to be Adis=1017.4+/-1.1 s-1 and Ea,dis=98+/-7 kcal mol-1.From the distribution of observed products it is concluded that the principal initiation reactions were analogous to those known to occur in toluene, the hydrocarbon analogue of 2-picoline, and were found to be C-C bond fission to yield o-pyridyl and methyl radicals and C-H fission to yield H atoms and 2-picolyl, the N-containing analogue of benzyl.Major products were observed from decomposition of both the o-pyridyl and the 2-picolyl radicals.Cyanoacetylene arises principally from the secondary reactions of o-pyridyl.A product with m/z 91 was observed at the lowest temperatures at which 2-picoline decomposition could be detected.It has been identified as 1-cyanocyclopentadiene and arises from loss of H from the 2-picolyl radical.Other products arising from secondary decomposition of 2-picolyl at higher temperatures include HCN and cyclopentadienyl radicals.
Microwave spectra and molecular structures of (Z)-pent-2-en-4-ynenitrile and maleonitrile
Halter,Fimmen,McMahon,Peebles,Kuczkowski,Stanton
, p. 12353 - 12363 (2001)
Accurate equilibrium structures have been determined for (Z)-pent-2-en-4-ynenitrile (8) and maleonitrile (9) by combining microwave spectroscopy data and ab initio quantum chemistry calculations. The microwave spectra of 10 isotopomers of 8 and 5 isotopomers of 9 were obtained using a pulsed nozzle Fourier transform microwave spectrometer. The ground-state rotational constants were adjusted for vibration-rotation interaction effects calculated from force fields obtained from ab initio calculations. The resultant equilibrium rotational constants were used to determine structures that are in very good agreement with those obtained from high-level ab initio calculations (CCSD(T)/cc-pVTZ). The geometric parameters in 8 and 9 are very similar; they also do not differ significantly from the all-carbon analogue, (Z)-hex-3-ene-1,5-diyne (7), the parent molecule for the Bergman cyclization. A small deviation from linearity about the alkyne and cyano linkages is observed for 7-9 and several related species where accurate equilibrium parameters are available. The data on 7-9 should be of interest to radioastronomy and may provide insights on the formation and interstellar chemistry of unsaturated species such as the cyanopolyynes.
Synthesis and characterization of 2,4-pentadiynenitrile - A key compound in space science
Trolez, Yann,Guillemin, Jean-Claude
, p. 7224 - 7226 (2005)
(Chemical Equation Presented) Spaced out: Cyanobutadiyne (3) was synthesized in pure form from 1,3-butadiynyltributylstannane (1) and p-toluene-sulfonyl cyanide (2). Diyne 3 might be formed in the atmosphere of Titan or in the interstellar medium by photolysis of mixtures of acetylene and cyanoacetylene or dicyanoacetylene or of butadiyne and dicyanoacetylene. Only 1,6-addition is observed with nucleophiles.
Crossed beam reaction of cyano radicals with hydrocarbon molecules. IV. Chemical dynamics of cyanoacetylene (HCCCN;X 1Σ+) formation from reaction of CN(X 2Σ+) with acetylene, C2H2(X 1Σg+)
Huang, L. C. L.,Asvany, O.,Chang, A. H. H.,Balucani, N.,Lin, S. H.,Lee, Y. T.,Kaiser, R. I.,Osamura, Y.
, p. 8656 - 8666 (2000)
The chemical reaction dynamics to form cyanoacetylene, HCCCN (X 1Σ+), via the radical-neutral reaction of cyano radicals, CN(X 2Σ+; ν = 0), with acetylene, C2H2(X 1Σg+), are unraveled in crossed molecular beam experiments at two collision energies of 21.1 and 27.0 kJ mol-1. Laboratory angular distributions and time-of-flight spectra of the HCCCN product are recorded at m/e = 51 and 50. Experiments were supplemented by electronic structure calculations on the doublet C3H2N potential energy surface and RRKM investigations. Forward-convolution fitting of the crossed beam data combined with our theoretical investigations shows that the reaction has no entrance barrier and is initiated by an attack of the CN radical to the ? electron density of the acetylene molecule to form a doublet cis/trans HCCHCN collision complex on the 2A' surface via indirect reactive scattering dynamics. Here 85 percent of the collision complexes undergo C-H bond rupture through a tight transition state located 22 kJ mol-1 above the cyanoacetylene, HCCCN (X 1Σ+) and H(2S1/2) products (microchannel 1). To a minor amount (15 percent) trans HCCHCN shows a 1.2-H shift via a 177 kJ mol-1 barrier to form a doublet H2CCCN radical, which is 46 kJ mol-1 more stable than the initial reaction intermediate (microchannel 2). The H2CCCN complex decomposes via a rather loose exit transition state situated only 7 kJ mol-1 above the reaction products HCCCN (X 1Σ+) and H(2S1/2). In both cases the geometry of the exit transition states is reflected in the observed center-of-mass angular distributions showing a mild forward/sideways peaking. The explicit identification of the cyanoacetylene as the only reaction product represents a solid background for the title reaction to be included in reaction networks modeling the chemistry in dark, molecular clouds, outflow of dying carbon stars, hot molecular cores, as well as the atmosphere of hydrocarbon rich planets and satellites such as the Saturnian moon Titan.
The 193-nm excimer laser photofragmentation of alkane and alkene nitriles in argon matrices
Machara, Nicholas P.,Ault, Bruce S.
, p. 6241 - 6245 (1988)
Excimer laser irradiation at 193 nm has been coupled with the matrix isolation technique for the study of fragmentation and rearrangement processes for acrylonitrile, crotononitrile, and 2-methyl-2-butenenitrile. For each of these systems, multiple fragmentation pathways were implicated, and the products for each system were characterized by infrared spectroscopy. For example, laser irradiation of acrylonitrile led to the formation of acetylene, hydrogen cyanide, and 2-propynenitrile. Irradiation was carried out both during the deposition process and after the matrix was rigidly frozen in place; differences were attributed to cage restrictions on recombination processes. Several simple alkyl nitriles were also subjected to laser irradiation, but for these systems no photoproducts were detected.
UV laser photodeposition of nanomagnetic soot from gaseous benzene and acetonitrile-benzene mixture
Pola, Josef,Ouchi, Akihiko,Mary?ko,Vorlí?ek,?ubrt, Jan,Bakardjieva,Bastl, Zdeněk
experimental part, p. 188 - 194 (2012/02/02)
Megawatt KrF laser gas-phase photolysis of benzene and acetonitrile-benzene mixture was studied by using mass spectroscopy-gas-chromatography and Fourier transform infrared spectroscopy for analyses of volatile products, and by Fourier transform infrared, Raman and X-ray photoelectron spectroscopy, electron microscopy and magnetization measurements for analyses of solid products deposited from the gas-phase. The results are consistent with carbonization of benzene and decomposition of non-absorbing acetonitrile in carbonizing benzene through collisions with excited benzene and/or its fragments. The solid products from benzene and acetonitrile-benzene mixture have large surface area and are characterized as nanomagnetic amorphous carbonaceous soot containing unsaturated C centers prone to oxidation. The nanosoot from acetonitrile-benzene mixture incorporates CN groups, confirms reactions of benzene fragments with CN radical and has a potential for modification by reactions at the CN bonds.
AMIDE COMPOUND
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Page/Page column 88, (2008/06/13)
There is provided a FAAH inhibitor and a prophylactic or therapeutic agent for cerebrovascular disorders or sleep disorders comprising it. The prophylactic or therapeutic agent comprises a compound of the formula (I0): wherein Z is oxygen or sulfur; R1 is aryl which may be substituted, or a heterocyclic group which may be substituted; R1a is a hydrogen atom, a hydrocarbon group which may be substituted, hydroxyl, etc.; R2 is piperidin-1,4-diyl which may be substituted, or piperazin-1,4-diyl which may be substituted; R3 is a group formed by eliminating two hydrogen atoms from a 5-membered aromatic heterocyclic group having 1 to 3 heteroatoms selected from nitrogen, oxygen and sulfur, which may be further substituted, -CO-, etc.; and R4 is a hydrocarbon group which may be substituted, or a heterocyclic group which may be substituted; or a salt thereof.
