| 摘要 |
1,236,170. Two-step conversion of toluene. UNION CARBIDE CORP. 24 Dec., 1969 [27 Dec., 1968], No. 62936/69. Heading C5E. Toluene is converted to benzene and ethylbenzene by (1) heating in the liquid phase in the presence of elemental sulphur to a temperature below the critical temperature of toluene to produce inter alia bibenzyl and stilbene, and (2) hydrodearalkylating and hydrodesulphurizing the product at 300-550‹ C. in the presence of a catalyst comprising at least one oxide of Cr, V or W together with an active, acidic component, e.g. silica-alumina, alumina-boria, magnesia-silica, boron phosphate, metal-exchanged and/or decationized molecular sieves, or acidtreated bentonite or kaolinite clays. The product of step (1) is preferably diluted before step (2), suitably with up to 10 times its weight of benzene. During step (2) stilbene is hydrogenated to bibenzyl, which splits to give benzene and ethylbenzene. |
