The reaction of hydrogen atoms with isobutene

Abstract

A detailed study has been made of the products of the reaction of hydrogen atoms with isobutene in a discharge flow reaction system at 290±3 K. Total pressures in the range 4 to 12 Torr (550 to 1650 N m -2 ) of argon were used and flow rates of hydrogen atoms and isobutene ranged individually up to about 10 μ mol s -1 . The main products were methane, ethane, ethylene, propane, propylene, isobutane and neopentane. A detailed mechanism accounting adequately for the observed product distributions and their dependence upon pressure and reactant mixture composition is proposed. The formation of the vibrationally excited species t-C 4 H 9 * is shown to be the predominant primary process. A number of rate constant ratios have been evaluated and absolute rate constants for some individual reactions have been estimated from the data. Some of the details of an earlier analogous study of the reaction of hydrogen atoms with propylene have been confirmed and some interesting correlations are indicated.