The influence of bromine compounds on combustion processes

Abstract

Studies of the effect of small additions of hydrogen bromide and of four bromomethanes on the slow combustion and spontaneous ignition of seven organic fuels show that the organic bromine compounds have a pronounced influence on the reactions only under conditions where they are themselves converted to hydrogen bromide or bromine. With all the fuels studied hydrogen bromide appears to have a promoting effect on at least certain stages of combustion. Only the oxidation of methane (and possibly formaldehyde) is retarded, the effect here being confined to the later stages of the reaction and to very small amounts of additive. Promotion by hydrogen bromide appears to be ascribable either to its direct reaction with oxygen providing an extra and more effective mode of chain-initiation or to its interaction with intermediate peroxides giving rise to enhanced chain-branching. Hydrogen bromide probably exerts its somewhat complex retarding influence on the later stages of the oxidation of methane by decreasing the rate of reaction of hydroxyl radicals with formaldehyde as a result of its preferential reaction with these chain-carriers.