GB752925A - A process for the isomerisation of waxy hydrocarbons - Google Patents

Abstract

Hydrocarbon mixtures containing at least 20 per cent by weight of waxy hydrocarbons are catalytically isomerized by passing a thin layer of the mixture in the liquid phase at an elevated temperature and in the presence of hydrogen, over a fixed bed of a solid catalyst which has dehydrogenating properties and an acid character. The catalyst may be platinum on a carrier such as alumina; or a metal of the sixth group, left-hand column, or platinum on aluminasilica+fluorine; platinum-molybdenum oxide on alumina+fluorine; nickel sulphide-tungsten sulphide on alumina+fluorine; or molybdenum oxide on boron oxide-alumina. The hydrogen, which may be in the form of a hydrogen containing gas is preferably passed in parallel flow with the liquid hydrocarbon from the top of the catalyst bed downwards. Preferred reaction conditions are temperature 400 DEG to 440 DEG C., pressure 25-40 atmospheres, contact time 0.5 to 10 minutes, throughput rate 1 to 5 kilograms per litre of catalyst per hour, molar ratio of hydrogen to hydrocarbon mixture 10 : 1 to 50 : 1. The product consists of paraffin waxes of an average molecular weight greater than 350 and a boiling-point above 300 DEG C. The hydrocarbon mixture may be purified before processing by a treatment with sulphuric acid, an extraction with a lower alkane such as propane, or a refining hydrogenation treatment. Specifications 634,602 and 713,910, [Group III], are referred to.ALSO:Hydrocarbon mixtures containing at least 20 per cent by weight of waxy hydrocarbons are catalytically isomerized by passing a thin layer of the mixture in the liquid phase at an elevated temperature and in the presence of hydrogen, over a fixed bed of a solid catalyst which has dehydrogenating properties and an acid character. The catalyst may be platinum on a carrier such as alumina; or a metal of the sixth group, left hand column, or platinum on alumina - silica + fluorine; platinum - molybdenum oxide on alumina + fluorine; nickel sulphide - tungsten sulphide on alumina + fluorine; or molybdenum oxide on boron oxide - alumina. The hydrogen, which may be in the form of a hydrogen containing gas is preferably passed in parallel flow with the liquid hydrocarbon from the top of the catalyst bed downwards. Preferred reaction conditions are temperature 400 DEG to 440 DEG C., pressure 25-40 atmospheres, contact time 0.5 to 10 minutes, throughput rate 1 to 5 Kilograms per litre of catalyst per hour, molar ratio of hydrogen to hydrocarbon mixture 10 : 1 to 50 : 1. The hydrocarbon mixtures may be paraffin waxes or fractions containing wax and oil. The hydrocarbon mixture may be purified before processing by a treatment with sulphuric acid, an extraction with a lower alkane such as propane, or a refining hydrogenation treatment. Specifications 634,602 and 713,910 are referred to.