| abstract |
The isomerisation of an olefinic acyclic hydrocarbon by skeletal rearrangement and/or double bond shift is effected in the presence of an anhydrous sulphate of manganese, a rare earth element (having an atomic number of 57-71 inclusive) or a metal of Group II, IV, V, VI or VIII. The sulphate may be of the formula X2(SO4)n in which X is a metal of valency n or it may be an acidic sulphate containing a hydrogen atom replaceable by a metal; nickel, magnesium and zinc sulphates are preferred. The sulphate is preferably obtained by dehydration of the hydrated salt and is then activated by heating, e.g. to 300 DEG C. for 1 hour in nitrogen. The process is effected in the vapour phase at 50-500 DEG C. and 0.1-10 v./v./hr. in the presence of nitrogen or other diluent in a mol. ratio to hydrocarbon of 0.1-10 : 1. Specified feedstocks are 3,3-dimethylbutene - 1, 4 - methylpentene - 1 (which forms 2-methylpentene-2) hexene-1 and cyclohexene (forming methylcyclopentenes). |