| 摘要 |
An alkylated benzene having 8-10 carbon atoms and in which the alkyl groups are methyl or ethyl is isomerised in the presence of hydrogen in a mol ratio to hydrocarbon of 1-20:1 and a catalyst comprising a physical mixture of (a) 5-75% by weight of an inert carrier on which is deposited sufficient platinum to comprise 0,1-2,5% by weight of the final catalyst and (b) a silica-alumina cracking component. Suitable conditions are 700 DEG -1000 DEG F., 50-500 p.s.i., and space velocities of 0,5-6 vol./vol./hr. The carrier for the platinum catalyst may be chi-, gamma-, or eta-alumina, alpha-alumina mono-hydrate, magnesia, calcium oxide, titania, silica gel, fullers' earth, kaolin, kieselguhr, diatomaceous earth, bauxite or an adsorbent clay. The cracking component may contain 7-30% alumina. The isomerisation of xylenes and ethylbenzene to give para-xylene (other isomers being recycled) is exemplified.ALSO:A catalyst for the isomerisation of alkyl benzenes comprises a physical mixture of (a) 5-75% by weight of an inert carrier on which is deposited sufficient platinum to comprise 0.1-2.5% by weight of the final catalyst and (b) a silica-alumina cracking component. Suitable carriers for portion (a) include chi-, gamma-, and eta-alumina, alpha-alumina monohydrate, magnesia, calcium oxide, titania, silica gel, fullers' earth, kaolin, kieselguhr, diatomaceous earth, bauxite and adsorbent clays. They are impregnated with aqueous solutions of chlorplatinic acid, platinous tetrammino chloride or hydroxide, platinic hexammino chloride or hydroxide, chlorplatinous acid, platinic chloride or ammonium chlorplatinate, dried and then calcined at 500-1100 DEG F. or treated with hydrogen at 400-1000 DEG F. either before or after mixing with the silica-alumina. The component (b) may contain 7-30% of alumina and have a surface area of 80-425 square metres per gram and may be treated with steam at 900-1400 DEG F. |
