GB1144495A - Improvements relating to the hydrogenation of benzene - Google Patents

Abstract

1,144,495. Cyclohexane. BRITISH PETROLEUM CO. Ltd. 29 June, 1966 [7 July, 1965], No. 28767/65. Heading C5E. Cyclohexane is obtained by a two-stage hydrogenation of benzene containing not more than 1 p.p.m. sulphur in the combined or uncombined form in which the first stage is cooled and operated to 90-99% by weight conversion and the second stage is uncooled and operated to substantially complete conversion. both stages employing a nickel on sepiolite catayst, particularly that prepared and activated according to Specification 899, 652. The catalyst may contain 1-50% by weight nickel, expressed as the element. Reaction conditions for the main hydrogenation reactor and the finishing reactor include a temperature of 77- 662‹ F. (25-350‹ C), pressure 25-2000 p.s.i.g., and space velocity 0.25-10.0 v./v./hr., the main reactor preferably being cooled by recycled cyclohexane product, using a product recycle ratio of 2 : 1 to 10 : 1, and being operated in mixed gas-liquid phase, and the finishing reactor operating at a lower temperature than the main reactor exit temperature, at a similar pressure, and in mixed gas/liquid phase or vapour phase. The hydrogenating gas may be commercially pure hydrogen, or a gas containing hydrogen and methane derived from steam reforming a naphtha or natural gas and comprising at least 50 mole per cent hydrogen. A preliminary desulphurization of the feedstock to 1 p.p.m. sulphur may be effected by passage over a nickel guard catalyst, particularly as disclosed in Specifications 1,144,498, 1,144,496 or 1,141,809.