Obtainment of Succinic Acid and Higher Alcohols (C8–С10) Diesters by Biphasic Esterification

Abstract

Biphasic esterification of model aqueous solutions of crystalline succinic acid or culture liquid obtained as a result of the growth of a succinic acid producer Yarowia lypolitica was studied. The main part of the study was performed with isooctyl (2-ethylhexyl) alcohol. Laurylsulfonic acid (another name dodecylsulfonic acid) was introduced as a catalyst. It was shown that the diester yield increases with an increase in the ratio alcohol/succinic acid solution, and it was higher than 90% when the ratio was 2 : 1. At a constant ratio of the phases described above, the product yield increased with a decrease in the concentration of succinic acid in the aqueous solution. More than 10% of the DSA catalyst passes into the alcohol phase; the compound can be extracted by Na₂CO₃ solution. The application of real culture liquid resulted in a significant decrease in the product yield as compared to the model succinic acid solutions. The process may become industrially promising with the selection of other efficient catalysts and improved microbial fermentation in order to decrease the content of related organic acid in the culture liquid.