Reaction of hydrogen atoms with cyclopropane in the temperature range from 628 to 779 K

Abstract

The reaction between cyclopropane and hydrogen atoms has been investigated in the temperature range from 628 to 779 K at a total argon pressure between 5.3 and 13.2 Torr using a discharge-flow system with gas-chromatographic product analysis. The measured products, methane, ethane, ethene, propane and propene, are shown to be consistent with a mechanism [graphic omitted] Measurement of k_w permits evaluation of the rate constant for the abstraction process log(k₁/cm³ mol^–1 s^–1)=(13.6 ± 1.0)–(48.5 ± 13.0 kJ mol^–1/2.3RT) which is similar to that for the corresponding reaction of methane on account of the almost identical C—H bond strengths in the molecules.

A composite function of the rate constants for addition to the two positions in propene is evaluated. It is shown that the flow rate of hydrogen atoms as measured by our previously described ethene titration technique gives values which are consistently only 80% of those evaluated by summation of the products of reaction with cyclopropane.