GB793215A - Hydrocarbon conversion process - Google Patents

Abstract

Aliphatic hydrocarbons containing at least six carbon atoms, at least one of which is a quaternary carbon atom, are heated with iodine or a compound which yields iodine under reaction conditions at an elevated temperature to give a different hydrocarbon by effecting bond cleavage and converting at least one quaternary carbon atom to a non-quaternary carbon atom. Reactions which may occur are isomerization, cyclization, dehydrogenation, aromatization, and dealkylation. The aliphatic hydrocarbon may be an alkane or alkene and preferably contains one quaternary carbon atom in a chain of at least five carbon atoms. The reaction may be carried out in the liquid or vapour phase in the presence of inert solids or catalysts or with a diluent. Temperatures of 300-600 DEG C. are preferred at atmospheric pressure with reaction times of 0.01 second to 5 minutes. The amount of iodine varies according to the desired reaction and particularly on the extent of dehydrogenation, and is preferably in the range 0.05 to 4 equivalents of iodine for each equivalent of hydrogen to be removed. Alkyl iodides such as ethyl, propyl or hexyl iodides may replace iodine as the reactant. In a typical example, 2,2,4-trimethyl pentane and iodine in an iodine/hydrocarbon ratio of 0.31 were heated in the vapour phase at 444 DEG C. and atmospheric pressure for 26 seconds. Xylenes, isobutane and isobutene were recovered as the principal products.