A two-stage process for the production of butane diol with between the separation of succinic anhydride

摘要

The present invention relates to a process for the production of optionally alkyl-substituted 1,4 - butanediol by means of two-stage catalytic hydrogenation in the gas phase, of c φ 4 φ - dicarboxylic acids and / or derivatives thereof, with the steps of: dollars a a) introducing a gas stream to a c φ 4 φ - dicarboxylic acid or a derivative thereof in the case of 200 to 300 deg c. and 2 to 60 bar in a first reactor and catalytic gas phase hydrogenation to a mainly optionally alkyl-substituted gamma - butyrolactone product containing; dollars a b) separation of succinic anhydride of the product obtained in step a), preferably to a residual content of about 0,3 to 0,2 w -%; dollars a is c) introduction of the product stream obtained in step b) in a second reactor at a temperature of 150 deg c. to 240 deg c and a pressure of 15 to 100 bar and catalytic gas phase hydrogenation to optionally alkyl-substituted 1,4 - butanediol; dollars a d) separating the desired product of intermediate products, by-products and possibly unreacted starting material; dollars a e), if appropriate, recycling of unreacted intermediates in one or both hydrogenation steps, dollar a wherein in both hydrogenation steps in each case a catalyst is used, of the 95 w -%, preferably 5 to 95 w -%, in particular 10 to 80 w -% cuo and & = 5 w -%, preferably 5 to 95 w -%, in particular 20 to 90 w -% of an oxidic support, and in the second reactor, a higher pressure prevails than in the first reactor.