Theoretical Kinetic Study of the Ring Opening of Cyclic Alkanes

TL;DR

This paper presents a comprehensive theoretical analysis of the gas phase decomposition pathways of cyclobutane, cyclopentane, and cyclohexane, using quantum chemical calculations to elucidate mechanisms and rate constants.

Contribution

It introduces a biradical mechanism model for cyclic alkane decomposition and provides thermochemical data and rate constants at various temperatures, validated against existing literature.

Findings

Good agreement with literature rate data

Identified main decomposition pathways for each cycloalkane

Provided thermochemical data for involved species

Abstract

This work reports a theoretical study of the gas phase unimolecular decomposition of cyclobutane, cyclopentane and cyclohexane by means of quantum chemical calculations. A biradical mechanism has been envisaged for each cycloalkane, and the main routes for the decomposition of the biradicals formed have been investigated at the CBS-QB3 level of theory. Thermochemical data (?H\degree f, S\degree, C\degree p) for all the involved species have been obtained by means of isodesmic reactions. Rate constants have been derived for all elementary reactions using transition state theory at 1 atm and temperatures ranging from 600 to 2000 K. These values have been compared with the few data available in the literature and showed a rather good agreement.