Cyclopropyl cyanide isomerizes in the gas phase at 660"-760"K and 2-89 torr to give mainly cis-and trans-crotonitrile and ally1 cyanide, with traces of methacrylonitrile. The reactions are first order, homogeneous, and unaffected by the presence of radical-chain inhibitors. Overall:The rate constants are given by log,ok/sec-l = (14.59 f 0.13) -(252.5 + 1.8) kJ mole-'/2.303 R T where the error limits afe standard deviations. On the basis of a biradical mechanism, it is deduced that the -CH-CN radical center is resonance stabilized by ca. 30 kJ mole-'. Approximate equilibrium data are given for interconversion of the 1-and 3-cyanopropenes.

Abstract'The high-pressure isotopic rate ratio k~/ k~ for isomerisation of cyclopropylamine and cyclopropylamine-N-d2 is 1.06 at 649-678 K, supporting a mechanism which does not involve migration of hydrogen from the amine group in the rate-determining step.

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