Kinetic Study Of The Gas Phase Pyrolysis Of Cis-1-Chloro-2-Butene

Lee, Yok-Chin (1980). Kinetic Study Of The Gas Phase Pyrolysis Of Cis-1-Chloro-2-Butene. MPhil thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000fc90

Abstract

The pyrolysis of cis-l-chloro-2-butene has been studied in temperature range 564 - 617 K, The predominant reaction is the elimination of HC1 by a pathway that is believed to be homogeneous and unimolecular. The Arrhenius parameters suggests a six-centred activated complex: $\text{log}\frac{k_1}{s^-1} = \text{12.81}\pm{0.77}- \frac {181800\pm8700 J mol^-1}{2.303 RT}$

This reaction is accompanied by a relatively slow isomerisation, cis-trans, which is shown to be heterogeneous. Subsequent polymerisation of the product, butadiene also occurs.

Comparisons of the rate data for the elimination reaction with that of structurally similar compounds and with alkyl halides can be made. It appears that in the six-centred mechanism the hydrogen plays a more important role in the formation of the incipient hydrogen halide molecule than it is generally thought to do in the more usual four-centred mechanism. Nevertheless, electron-releasing groups have a large effect on the rate, similar to that observed in ester pyrolysis, and hence it is inferred that there is substantial development of polarity in the six-centred mechanism.