Journal of Physical Chemistry A, Vol.115, No.13, 2727-2734, 2011
H Atom Attack on Propene
The reaction of propene (CH3CH=CH2) with hydrogen atoms has been investigated in a heated single-pulsed shock tube at temperatures between 902 and 1200 K and pressures of 1.5-3.4 bar. Stable products from H atom addition and H abstraction have been identified and quantified by gas chromatography/flame ionization/mass spectrometry. The reaction for the H addition channel involving methyl displacement from propene has been determined relative to methyl displacement from 1,3,5-trimethylbenzene (135TMB), leading to a reaction rate, k(H + propene) -> H2C=CH2 + CH3) = 4.8 x 10(13) exp(-2081/T) cm(3)/(mol s). The rate constant for the abstraction of the allylic hydrogen atom is determined to be k(H + propene -> CH2CH=CH2 + H-2) = 6.4 x 10(13) exp(-4168/T) cm(3)/(mol s). The reaction of H + propene has also been directly studied relative to the reaction of H + propyne, and the relationship is found to be log[k(H + propyne -> acetylene + CH3)/k(H + propene -> ethylene + CH3)] = (-0.461 +/- 0.041)(1000/T) + (0.44 +/-0.04). The results showed that the rate constant for the methyl displacement reaction with propene is a factor of 1.05 +/- 0.1 larger than that for propyne near 1000 K. The present results are compared with relevant earlier data on related compounds.