Cyclisation in the Gas Phase Photolysis of Neopentyl Bromide

Abstract

Gas phase photolysis of neopentyl bromide was studied over the temperature range 478-564 K. The major products were hydrogen bromide, 1,1-dimethylcyclopropane, with smaller amounts of methylbutenes and neopentane. Above initial reactant pressures of 50 kPa the overall rate expression is given by: -d[npb]/dr = A-[npb] I°-\ where Io is the incident light intensity. The overall activation energy is 58.5 kJ mol-1. The principal propagation step is the cyclisation of the 3-bromo-2,2-dimethylpropyl radical to 1 1- dimethylcyclopropane and a bromine atom.