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Abstract

Three aspects of the isomerization reaction of cyclopropane to propylene were explored, in order to evaluate the suitability of this rearrangement for use as a model reaction in studying the effects of pore diffusion on the rates of chemical change in porous solids. First, kinetic data for this reaction were extended from 555°C to 620°C, with good agreement being obtained with data of others at temperatures below 555°C For the results of this work, as well as for all other published results, the first order homogeneous rate constant at infinite pressure can be represented by log₁₀ k =15.38 [formula omitted] (T in degrees Kelvin) with an accuracy of ± 15% over the temperature range 470°- 620°C. Second, the isomerization was shown to proceed homogeneously in the presence of Pyrex surfaces, even with 60-fold changes in-the surface to volume ratio. Third, the only side reaction of any importance was the decomposition of propylene, which was found to be about 20-50 times slower than the cyclopropane isomerization. These results indicate that the cyclopropane reaction is a satisfactory one for the purposes of studying diffusion controlled processes, but the propylene pyrolysis may restrict the range of desirable experimental conditions.