Process of separation of glyoxylic acid from an aqueous reaction medium containing glyoxylic acid and hydrochloric acid
View Patent ↗The invention relates to a process for separating glyoxylic acid starting from an aqueous reaction medium containing glyoxylic acid and hydrochloric acid, comprising a step of countercurrent steam stripping of the reaction medium in order to obtain, on the one hand, a gas phase containing the volatile hydrochloric acid and, on the other hand, a liquid phase containing the purified glyoxylic acid.
1. A process for separating glyoxylic acid starting from an aqueous reaction medium containing glyoxylic acid and hydrochloric acid, comprising a step of countercurrent steam stripping of the reaction medium to obtain, a gas phase containing the volatile hydrochloric acid and a liquid phase containing the purified glyoxylic acid.
2. A process according to claim 1 , wherein the aqueous reaction medium contains less than 30% by weight of water.
3. A process according to claim 1 , wherein the aqueous reaction medium contains less than 25% by weight of water.
4. A process according to claim 1 , wherein the countercurrent stripping step is carried out under a pressure less than atmospheric pressure.
5. A process according to claim 4 , wherein the countercurrent stripping step is carried out under a pressure of less than 30000 Pa.
6. A process according to claim 1 , wherein the aqueous reaction medium containing glyoxylic acid and hydrochloric acid is obtained by oxidation of glyoxal in the presence of hydrochloric acid.
7. A process according to claim 1 , wherein the hydrochloric acid concentration in the aqueous reaction medium is less than or equal to 2% by weight.
8. A process according to claim 1 , wherein the hydrochloric acid concentration in the aqueous reaction medium is less than or equal to 0.5% by weight.
9. A process according to claim 1 , wherein the hydrochloric acid concentration in the liquid phase containing the purified glyoxylic acid is less than or equal to 250 ppm.
10. A process according to claim 9 , wherein the hydrochloric acid concentration in the liquid phase containing the purified glyoxylic acid is less than or equal to 50 ppm.
11. A process according to claim 1 , wherein the aqueous reaction medium contains 70% to 80% by weight of glyoxylic acid, 0 to 5% by weight of oxalic acid and 0 to 5% by weight of glyoxal.
12. A process according to claim 1 , wherein the steam to reaction medium ratio is between 0.1 and 10 by weight.
13. A process according to claim 12 , wherein the steam to reaction medium ratio is between 0.2 and 2 by weight.
14. A process according to claim 1 , wherein the aqueous reaction medium containing glyoxylic acid and hydrochloric acid is preheated.
15. A process according to claim 1 , wherein the aqueous reaction medium containing glyoxylic acid and hydrochloric acid is preheated to a temperature between 50 and 100° C.
16. A process according to claim 9 , wherein the hydrochloric acid concentration in the liquid phase containing the purified glyoxylic acid is less than or equal to 30 ppm.
17. A process according to claim 4 , wherein the countercurrent stripping step is carried out under a pressure of less than 10000 Pa.
18. A process according to claim 1 , wherein the hydrochloric acid concentration in the liquid phase containing the purified glyoxylic acid is less than or equal to 100 ppm.