Patent ID: 7154011
Filing Date: 2006-12-26
Classification: C07C,Y02P

Abstract:
1. A process for preparing optionally alkyl-substituted 1,4-butanediol by two-stage catalytic hydrogenation in the gas phase of C 4 -dicarboxylic acids and/or of derivatives thereof having the following steps: a) introducing a gas stream of a C b) introducing the product stream obtained in this way into a second reactor or into a second reaction zone of a reactor at a temperature of from 140° C. to 260° C. and catalytically hydrogenating it in the gas phase to optionally alkyl-substituted 1,4-butanediol; c) removing the desired product from intermediates, by-products and any unconverted reactant; d) optionally recycling unconverted intermediates into one or both hydrogenation states, said hydrogenation stages each using a catalyst which comprises ≦95% by weight of CuO, and ≧5%, of an oxidic support, and the product mixture removed from the first hydrogenation stage being introduced without further purification into the second hydrogenation stage.