14936-94-8Relevant articles and documents
Thermal Decomposition Mechanism for Ethanethiol
Vasiliou, AnGayle K.,Anderson, Daniel E.,Cowell, Thomas W.,Kong, Jessica,Melhado, William F.,Phillips, Margaret D.,Whitman, Jared C.
, p. 4953 - 4960 (2017)
The thermal decomposition of ethanethiol was studied using a 1 mm x 2 cm pulsed silicon carbide microtubular reactor, CH3CH2SH + Δ → Products. Unlike previous studies these experiments were able to identify the initial ethanethiol decomposition products. Ethanethiol was entrained in either an Ar or a He carrier gas, passed through a heated (300-1700 K) SiC microtubular reactor (roughly ≤100 μs residence time) and exited into a vacuum chamber. Within one reactor diameter the gas cools to less than 50 K rotationally, and all reactions cease. The resultant molecular beam was probed by photoionization mass spectroscopy and IR spectroscopy. Ethanethiol was found to undergo unimolecular decomposition by three pathways: CH3CH2SH → (1) CH3CH2 + SH, (2) CH3 + H2C=S, and (3) H2C=CH2 + H2S. The experimental findings are in good agreement with electronic structure calculations. (Chemical Equation Presented).
Association Reactions at Low Pressure. 2. The CH3+/CH3CN System
McEwan, Murray J.,Denison, Arthur B.,Huntress, Wesley T. Jr.,Anicich, Vincent G.,Snodgrass, J.,Bowers, M. T.
, p. 4064 - 4068 (1989)
The reaction between CH3+ and CH3CN has been examined at pressures between 8E-8 and 1E-3 Torr in an ion cyclotron resonance mass spectrometer.At low pressures the reaction is bimolecular, having a rate coefficient of 1.8E-9 cm3s-1.The major ion products are H2CN+ and C2H5+, but a bimolecular association channel also competes with these two main binary exotermic channels.At pressures above ca. 4E-5 Torr the termolecular associaton (CH3CNCH3+) reaction becomes the major reaction.The results are rationalized in terms of barriers on the potential energy surface of the binary exit channels.The rate coefficient observed for the termolecular associaton reaction CH3+ + CH3CN + M CH3CNCH3+ + M was found to be k=1.90E-22 cm6 s-1 when M=CH3CN, and when M=N2, Ne, and He, k=4.0E-23, 0.6E-23, and 1.0E-23 cm6 s-1 respectively.The lifetime of the collision complex was found to be >14 μs.
Chemical ionization using CF3+: Efficient detection of small alkanes and fluorocarbons
Dehon, Christophe,Lemaire, Jo?l,Heninger, Michel,Chaput, Aurélie,Mestdagh, Hélène
experimental part, p. 113 - 119 (2011/08/21)
The trifluoromethyl ion CF3+ is evaluated as a chemical ionization (CI) precursor in a compact Fourier Transform Ion Cyclotron Resonance (FTICR) mass spectrometer. It reacts with alkanes by hydride abstraction allowing characterization and quantification of alkanes up to C4 and cyclic. With larger alkanes fragmentation occurs. Fluorocarbons react by fluoride abstraction. Rate coefficients have been measured for reaction with alkanes, fluoroalkanes, chlorofluoroalkanes as well as several common VOCs. Use of CF3+ for trace analysis in air has been tested on an air sample containing traces of acetone, toluene, benzene and cyclohexane. The results are consistent with those obtained with H3O+ precursor and allow additional cyclohexane quantification.
Ion - Molecule Reaction Studies of Hydroxyl Cation and Ionized Water with Ethylene
Fishman, Vyacheslav N.,Grabowski, Joseph J.
, p. 4879 - 4884 (2007/10/03)
Rate coefficients and product branching ratios for the ion - molecule reactions of the hydroxyl cation, ionized water, and their deuterated analogues with ethylene have been determined using a selected ion flow tube (SIFT) at room temperature and in 0.5 Torr of helium buffer gas. In all cases, reactions proceed at or near the collision rate. The major product is always charge transfer: 79% for L2O?+and 66% for LO+ and does not depend on the isotopic form of hydrogen present (L = H or D). For the L2O?+ reactions, the remaining 21% of products are from proton or deuteron transfer, with no evidence of an isotope effect on this step even in the HOD?+ reaction. The greater exothermicity of the initial charge transfer in the LO+ reaction is revealed by the observation of additional product channels, forming the vinyl cation and protonated carbon monoxide. Multistep mechanisms that proceed through rate-determining charge-transfer, followed by a product-determining step, are postulated to explain these observations.
