| abstract |
Gamma-butyrolactone is produced by vapour phase hydrogenolysis of an alkyl ester of a C4 dicarboxylic acid, e.g. diethyl maleate, over a reduced Cu-Cr or Cu-Zn mixed oxide catalyst. Two adiabatic hydrogenolysis zones are used. The mixture exiting the first of these zones is heated (by, for example 5oC) and the resulting heated mixture is fed to the second zone in which it reequilibriates at a higher temperature to increase the butane-1,4-diol yield at the expense of butane-1,4-diol. Typical reaction conditions include use of temperatures of 190oC to 260oC, pressures of 3 to 30 bar, and an H2:ester molar ratio of 50:1 to 1000:1. |