Preparation in a condition of purity of hydrocarbons from mixtures containing them

Claim 1

A PROCESS FOR THE PREPARATION OF A PURE HYDROCARBON FROM A FEEDSTOCK CONSISTING ESSENTIALLY OF N-HEXANE, BENZENE, METHYLCYCLOPENTANE, CYCLOHEXANE AND 2,2- AND 2,4-DIMETHYLPENTANES, WHICH COMPRISES THE DISTILLATION OF THE FEEDSTOCK IN AN INITIAL DISTILLATION ZONE TO REMOVE A PRIMARY FRACTION DISTILLING AT A TEMPERATURE NOT ABOVE 81.1*C., THE PRIMARY FRACTION BEING DISTILLED IN A SECOND DISTILLATION ZONE IN THE PRESENCE OF SUFFICIENT AZEOTROPE-FORMING HYDROCARBON, SUCH AS BENZENE, TO ENSURE THE RECOVERY OF PURE CYCLOHEXANE AS A RESIDUAL FRACTION, AN OVERHEAD FRACTION ALSO BEING TAKEN COMPRISING ANY CYCLOHEXANE NOT RETAINED IN THE RESIDUE FRACTION, TOGETHER WITH AZEOTROPIC MIXTURES COMPRISING METHYLCYCLOPENTANE AND DIMETHYLPENTANES WITH BENZENE AND ANY OTHER AZEOTROPE-FORMING HYDROCARBON PRESENT, TOGETHER WITH ALL OTHER CONSTITUENTS OF THE FEEDSTOCK TO THE SECOND DISTILLATION ZONE, THE OVERHEAD FRACTION THEN BEING TREATED FOR THE RECOVERY OF SUBSTANTIALLY THE WHOLE OF THE BENZENE IN THE OVERHEAD FRACTION AND THE PRODUCTION OF A BENZENE-FREED FRACTION, THE SAID BENZENE-FREED FRACTION BEING THEN PASSED TO AN ISOMERISATION ZONE IN WHICH A SUBSTANTIAL PART OF ITS METHYLCYCLOPENTANE CONTENT IS COVERTED INTO CYCLOHEXANE, AND A SUBSTANTIAL PART OF THE 2,2-DIMETHYLPENTANE AND 2,4-DIMETHYLPENTANE CONVERTED TO HYDROCARBONS OF DIFFERENT BOILING POINT.