31533-72-9Relevant articles and documents
Atmospheric Chemistry of Dimethyl Sulfide: UV Spectra and Self-Reaction Kinetics of CH3SCH2 + O2 -> CH3SCH2O2 and CH3SCH2O2 + NO -> CH3SCH2O + NO2
Wallington, Timothy J.,Ellermann, Thomas,Nielsen, Ole J.
, p. 8442 - 8449 (1993)
A pulse radiolysis technique has been used to measure the UV spectra of CH3SCH2 and CH3SCH2O2 radicals over the range 225-350 nm.At 285 nm, ?(CH3SCH2) = (9.8 +/- 1.7) X 10-18; at 250 nm, ?(CH3SCH2O2) = (4.3 +/- 0.7) X 10-18 cm2 molecule-1.Observed self-reaction rate constants, defined as -d/dt = 2k62 and -d/dt = 2k7obs2, were k6 = (3.0 +/- 0.6) X 10-11 and k7obs = (7.9 +/- 1.4) X 10-12 cm3 molecule-1 s-1.Errors are statistical (2 standard deviations) plus our estimate of potential systematic uncertainty (15percent).A rate constant, k2 = (5.7 +/- 0.4) X 10-12 cm-3 molecule-1 s-1, was derived for the addition reaction CH3SCH2 + O2 -> CH3SCH2O2.A rate constant, k3 = (1.9 +/- 0.6) X 10-11 cm3 molecule-1 s-1, is reported for the reaction of CH3SCH2O2 radicals with NO, producing NO2.Errors for k2 and k3 are 2 standard deviations.Results are discussed with respect to the atnospheric chemistry of dimethyl sulfide.
Temperature-Dependent Kinetics Studies of the Reactions Br(2P3/2) + CH3SCH3 CH3SCH2 + HBr. Heat of Formation of the CH3SCH2 Radical
Jefferson, A.,Nicovich, J. M.,Wine, P. H.
, p. 7128 - 7135 (1994)
Time-resolved resonance fluorescence detection of Br(2P3/2) atom disappearence or appearance following 266-nm laser flash photolysis CF2Br2/CH3SCH3/H2/N2 and Cl2CO/CH3SCH3/HBr/H2/N2 mixtures has been employed to study the kinetics of the reactions Br((2)P3/2) + CH3SCH3 HBr + CH3SCH2 (1,-1) as a function of temperature over the range 386 604 K.Arrhenius expressions in units of cm3 molecule-1 s-1 which describe the results are k1 = (9.0 +/- 2.9) x 1E-11 > and k-1 = (8.6 +/- 2.5) x 1E-13 >; errors are 2? and represent precision only.To our knowledge, these are the first kinetic data reported for each of the two reactions studied.Second and third law analyses of the equilibrium data for reactions 1 and -1 have been employed to obtain the following enthalpies of reaction in units of kcal mol-1; ΔH298 = 6.11 +/- 1.37 and ΔH0 = 5.37 +/- 1.38.Combining the above enthalpies of reaction with the well-known heats of formation of Br, HBr, and CH3SCH3 gives the following heats of formation of the CH3SCH2 radical in units of kcal mol-1: ΔHf,298 = 32.7 +/- 1.4 and ΔHf,0 = 35.3 +/- 1.4; errors are 2? and represent estimates of absolute accuracy.The C-H bond dissociation energy in CH3SCH3 obtained from our data, 93.7 +/- 1.4 kcal mol-1 at 298 K and 92.0 +/- 1.4 kcal mol-1 at 0 K, agrees well with a recent molecular beam photofragmentation study but is 3 kcal mol-1 lower than the value obtained from an iodination kinetics study.
THERMODYNAMICS OF S THEREFORE S2 sigma /1 sigma * THREE-ELECTRON BONDS AND DEPROTONATION KINETICS OF THIOETHER RADICAL CATIONS IN AQUEOUS SOLUTION.
Moenig,Goslich,Asmus
, p. 115 - 121 (2007/10/02)
These experiments on the determination of K//1 and the associated rate constants were conducted at various temperatures and thus provided for the first time experimentally determined thermodynamic parameters ( DELTA H** does not equal and DELTA S** does not equal ) for the unimolecular dissociation of the three-electron bond. This in turn will allow an experimental estimate for the sulfur-sulfur bond strength in (R//2S therefore SR//2)** plus . Up to now only a theoretical ab-initio value has been published, namely 130 kJ mol** minus **1 for the simplest congeneric species with all R equals H. The kinetic and thermodynamic results substantiate previous conclusions on the electronic structure and relative stability of S therefore S bonded radicals and corroborate some theoretical calculations.
