| 摘要 |
Hydrocarbons are isomerized in the presence of a catalyst comprising a platinum-group metal supported on a refractory metal oxide and containing 2-5% by weight of combined fluorine and less than 0.075% of combined chlorine. The metal which may be palladium, ruthenium, rhodium, osmium, iridium or, preferably, platinum, may be present in amounts of 0.1-2%. The refractory oxide can be alumina, titania, zirconia, chromia, zinc oxide, silica-alumina, chromia-alumina, alumina-boria, silica-zirconia, bauxite, kaolin or bentonite clay which may have been acid-treated, kieselguhr, montmorillonite, magnesia-alumina spinel or zinc oxide spinels; synthetic gamma-alumina is preferred. The hydrocarbon to be treated can be a straight-chain or mildly branched paraffin of more than four carbon atoms including n-pentane, 2- or 3-methylpentane, n-hexane, 2- or 3-methyl hexane, n-heptane and n-octane, cycloparaffins containing at least five carbon atoms in the ring including mono- or dimethylcyclopentane, cyclohexane, mono- or dimethylcyclohexane and ethylcyclohexane, and alkyl aromatic hydrocarbons including ethylbenzene, and propylbenzene. Mixtures of paraffins and/or naphthenes can also be used. Preferred conditions are 250-475 DEG C. and 6.8-102 atmospheres at liquid hourly space velocities of 0.5-100 in the presence of 0.5-10 moles. of hydrogen per mole. of hydrocarbon. |
