Relative Rates of Reaction of Hydrogen Atoms with Olefins

A new technique has been developed and used to redetermine the rates of H atom reactions at room temperature with a number of simple olefins. Hydrogen atoms are generated by the mercury photosensitized decomposition of H2 in the presence of small amounts of ethylene or its mixtures with an added olefin. The relative rate constants are determined from a comparison of the yields of n-butane in the two cases. The values obtained are compared with the earlier determinations and with another independent recent redetermination in this laboratory. The values obtained by the three independent techniques are in very good agreement.