Patent ID: 9738588
Date: 2017-08-22
CPC Classifications: B01D,C07C

Claim:
1. A process for continuously preparing di-C 1-3 -alkyl succinates by reacting succinic acid with an C 1-3 -alkanol in the presence of a fixed-bed heterogeneous acidic esterification catalyst in a tubular reactor at a temperature in a range of from 60 to 100° C., wherein a mixture, comprising succinic acid, C 1-3 -alkanol, mono-C 1-3 -alkyl succinate, di-C 1-3 -alkyl succinate, and water, is formed in a mixing stage and fed to an entrance of the tubular reactor, and wherein 5 to 75% of an outlet flow rate of the tubular reactor is recycled directly to the mixing stage as a recycle stream, and a molar ratio of C 1-3 -alkanol to succinic acid added to the mixing zone, and not including the C 1-3 -alkanol and succinic acid of the recycle stream, is in the range of from 2.0 to 9.5.