Patent GB-585958-A (GB)
Title: Improvements in and relating to the dehydrogenation of naphthenes to aromatic hydrocarbons
IPC: C07C5/367
Filed: 1944-07-21
Abstract: Hexamethylene naphthenes, in mixtures also containing pentamethylene naphthenes, paraffins, unsaturated hydrocarbons, sulphur, and/or sulphur compounds, are dehydrogenated to aromatic hydrocarbons in the presence of added hydrogen, and a catalyst consisting of platinum and/or palladium supported on active carbon, at not more than 450 DEG C. and at 3-10 atmospheres absolute hydrogen partial pressure. Petrols containing hexamethylene naphthenes may be treated to improve their anti-knock quality. They may first be fractionated as described in Specification 577,813, [Group IV], and the fraction or fractions richer in these naphthenes treated, the product being blended with untreated fractions.  Thus, a cut may be made at 80-120, e.g., 95 DEG C., and the bottom fraction treated.  The initial materials may be pretreated to remove sulphur, unsaturated compounds, carbon monoxide or substances capable of giving it, and nitrogen compounds.  The catalysts are preferably prepared as described in Specification 577,862.  In an example, a petrol containing 11 per cent. aromatics, 48 per cent. naphthenes, and 41 per cent. paraffins is separated into fractions of B.R. up to 95, and 95-130 DEG C.  The latter is passed with hydrogen through a preheater, through active carbon and zinc oxide for sulphur removal, and then through platinum on active carbon at 365 DEG C., and 5 atmospheres. The products, at 3.5 atmospheres, are cooled to separate hydrogen, which is recycled, and a petrol containing 38.4 per cent. aromatics, which is blended with the original fraction boiling up to 95 DEG C.ALSO:Hexamethylene naphthenes, in mixtures also containing pentamethylene naphthenes, paraffins, unsaturated hydrocarbons, sulphur and/or sulphur compounds, are dehydrogenated to aromatic hydrocarbons in the presence of added hydrogen, and a catalyst consisting of platinum and/or palladium supported on active carbon, at not more than 450 DEG C. and at 3-10 atmospheres absolute hydrogen partial pressure. Petrols containing hexamethylene naphthenes may be treated to improve their anti-knock quality.  They may first be fractionated as described in Specification 577,813, and the fraction or fractions richer in these naphthenes treated, the product being blended with untreated fractions.  Thus, a cut may be made at 80-120 DEG , e.g. 95 DEG  C., and the bottom fraction treated.  The initial materials may be pre-treated to remove sulphur, unsaturated compounds, carbon monoxide or substances capable of giving it, and nitrogen compounds. The catalysts are preferably prepared as described in Specification 577,862, [Group III].  In an example, a petrol containing 11 per cent aromatics, 48 per cent naphthenes, and 41 per cent paraffins is separated into fractions of B.R. up to 95 DEG  and 95-130 DEG  C. The latter is passed with hydrogen through a preheater, through active carbon and zinc oxide for sulphur removal, and then through platinum on active carbon at 365 DEG  C. and 5 atmos.  The products, at 3.5 atmos., are cooled to separate hydrogen, which is recycled, and a petrol containing 38.4 per cent aromatics, which is blended with the original fraction boiling up to 95 DEG  C.