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]/dt=k[npb]I^0.5₀, where I₀ 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.