Determination of the ratios of the rate constants of elementary reactions of chain propagation during pyrolysis of various saturated hydrocarbons

A study was made of the pyrolysis of mixtures of cyclopentane with ethane and pentane and of cyclohexane with ethane and hexane at 710 to 880/sup 0/C. It is shown that the ratios of the overall rate constants of the decomposition of saturated hydrocarbons in a mixture are equal to: k/sub C/sub 5/H/sub 10// : k/sub C/sub 2/H/sub 6// = 5.3 +- 1.2(855 to 878/sup 0/), k/sub C/sub 5/H/sub 10// : k/sub C/sub 5/H/sub 12// = 0.67 +- 0.18(750 to 830/sup 0/C), k/sub C/sub 6/H/sub 12// : k/sub C/sub 2/H/sub 6// = 8.4 +- 1.3(760 to 850/sup 0/C), and k/sub C/sub 6/H/sub 12// : k/sub C/sub 6/H/sub 14// = 0.97 +- 0.22(710 to 860/sup 0/C). These values are close to the ratio of the rate constants of the elementary reactions of chain propagation R' + RH ..-->.. R'H + R. The relative reactivities of the secondary C-H bonds in these reactions are determined. 3 tables.