A PROCESS FOR PREPARING SUCCINIC ACID AND SUCCINATE ESTER
This invention relates to a process for preparing succinic acid and succinate ester from a succinic acid salt in fermentation broth. In the first stage of this invention, renewable carbon resources are utilized to produce succinic acid through biological fermentation. The succinic acid salt in the fermentation process is subjected to double displacement reaction with a strong acid leading to release of succinic acid. Succinic acid is recovered by fractional crystallization integrated with simulated moving bed chromatography to produce succinic acid and succinate ester.
1 . A process for preparing succinic acid comprising the steps of:
a. fermentation of carbohydrate substrates using a biocatalyst to produce a succinate salt;
b. clarification of fermentation broth to remove biocatalyst, proteins, and insolubles;
c. concentration of said clarified fermentation broth from step (b);
d. acidification of concentrated fermentation broth from step (c);
e. controlled crystallization of succinic acid in the acidified and concentrated fermentation broth from step (d);
f. separating crystalline succinic acid from mother liquor; and
g. subjecting said mother liquor to simulated moving bed chromatography to recover remaining succinic acid; and
h. crystallizing said succinic acid recovered in step (g).
2 . A process for preparing succinic acid as in claim 1 wherein said acidification of concentrated fermentation broth is carried out using sulfuric acid.
3 . A process for preparing succinate ester comprising the steps of:
a. fermentation of carbohydrate substrates using a biocatalyst to produce a succinate salt;
b. clarification of fermentation broth to remove biocatalyst, proteins, and insolubles;
c. concentration of said clarified fermentation broth from step (b);
d. acidification of concentrated fermentation broth from step (c);
e. controlled crystallization of succinic acid in the acidified and concentrated fermentation broth from step (d);
f. separating crystalline succinic acid from mother liquor;
g. dissolving said crystalline succinic acid from step (f) in methanol;
h. esterification of said succinic acid dissolved in methanol in step (g);
i. subjecting said mother liquor from step (f) to simulated moving bed chromatography to recover remaining succinic acid;
j. crystallizing said succinic acid recovered in step (i);
k. dissolving crystalline succinic acid from step (j) in methanol;
l. esterifying said succinic acid dissolved in methanol in step (k); and
m. recovering succinate ester from steps (h) and (l) through fractional distillation.
4 . A process for preparing succinic acid as in claim 3 wherein said acidification of concentrated fermentation broth is carried out using sulfuric acid.
5 . A process for preparing succinate ester as in claim 3 wherein sulfur content of said succinate ester is below 50 ppm level.
6 . A process for preparing succinate ester as in claim 3 wherein sulfur content of said succinate ester is below 10 ppm level.
7 . A process for preparing succinic acid and succinate ester comprising the steps of:
a. fermentation of carbohydrate substrates using a biocatalyst to produce a succinate salt;
b. clarification of fermentation broth to remove biocatalyst, proteins, and insolubles;
c. concentration of said clarified fermentation broth from step (b);
d. acidification of concentrated fermentation broth from step (c);
e. controlled crystallization of succinic acid in the acidified and concentrated fermentation broth from step (d);
f. separating crystalline succinic acid from mother liquor;
g. dissolving said crystalline succinic acid crystal form step (f) in methanol;
h. esterification of said succinic acid dissolved in methanol in step (g);
i. recovering succinate ester from step (h) through fractional distillation;
j. subjecting said mother liquor from step (f) to simulated moving bed chromatography to recover remaining succinic acid; and
k. crystallizing said succinic acid from step (j).
8 . A process for preparing succinic acid as in claim 7 wherein said acidification of concentrated fermentation broth is carried out using sulfuric acid.