Succinic Acid → Butanedioic acid;butane-1,4-diol

Participants

Reaction Steps

A solution of 590.5 g (5 mol) of succinic acid in 504.7 g (5.6 mol) of 1,4-butanediol was placed in the first reactor of the same reactor cascade as in Example 1, the solution was heated with stirring to a reaction temperature of 130°-140° C., and the water of reaction which formed was distilled off under atmospheric pressure. After a residence time of 2 hours, the reaction mixture was run into the adjacent second reactor, where a further portion of the water of reaction was distilled off under atmospheric pressure at a reaction temperature of 140°-160° C. Finally, after a residence time of 1 hour, the reaction mixture was run into the third reactor and the remainder of the water of reaction was removed under a pressure of 800 mbar and at a reaction temperature of 160° C. After a reaction time of 2 hours more (5 hours in all), the desired degree of esterification had been reached. The oligomeric butane-1,4-diol succinate obtained (1,005 g) had an average degree of oligoesterification of n=5 (molecular mass distribution measured by gel permeability chromatography) and an acid number of 46 mg of KOH/g of reaction mixture. Following the partial or complete emptying of the first and/or second reactor, it was possible to continue the esterification process continuously by adding new quantifies of reaction mixture.

Provenance & Evidence