Cyclic process for the production of taurine from ethylene oxide
View Patent ↗The present invention discloses a cyclic process for the production of taurine from ethylene oxide in a high yield of greater than 95% by continuously converting the byproducts of the ammonolysis reaction, sodium ditaurinate and sodium tritaurinate, to sodium taurinate. The cyclic process is completed by using sulfur dioxide or sulfurous acid to neutralize sodium taurinates to recover taurine and to regenerate sodium bisulfite, which is then reacted with ethylene oxide.
1. A cyclic process for the production of taurine from ethylene oxide in high yield, comprising,
(a) Reacting ethylene oxide with sodium bisulfite in the presence of taurine, sodium ditaurinate, and sodium tritaurinate, to yield a mixture of sodium isethionate and sodium taurinates;
(b) Adding sodium hydroxide to (a) to convert excess sodium bisulfite to sodium sulfite, taurines to sodium taurinates;
(c) Adding ammonia to (b) and subjecting the solution to the ammonolysis reaction to yield a mixture of sodium taurinates in the presence of catalysts;
(d) Removing excess ammonia from (c) and neutralizing sodium taurinates with sulfur dioxide or sulfurous acid to form a crystalline suspension of taurine in a solution of sodium ditaurinate, sodium tritaurinate, and sodium bisulfite;
(e) Recovering taurine from (d), and returning most of the mother liquor to (a) to react with ethylene oxide.
2. The process according to claim 1 wherein the overall yield is from greater than 90%.
3. The process according to claim 1 (b) wherein the amount of sodium hydroxide is from 1 to 25% of sodium isethionate.
4. The process according to claim 1 (c) wherein the molar ratio of ammonia to sodium isethionate is from 5 to 15.
5. The process according to claim 1 (c) wherein the catalysts are alkali hydroxide and alkali carbonate.
6. The process according to claim 1 (e) wherein part of the mother liquor is taken out from the cyclic process and adjusted to pH 9 to 12 with sodium hydroxide to form sodium sulfite and sodium taurinates.
7. The process according to claim 6 wherein sodium sulfite is separated from sodium taurinates by evaporative crystallization and cooling crystallization.
8. The process according to claim 7 wherein the mother liquor after filtration of sodium sulfite is saturated with ammonia and returned to the ammonolysis step or subjected to the ammonolysis reaction to yield a mixture of sodium taurinates.
9. The process according to claim 2 , wherein the overall yield is greater than 95%, to nearly quantitative.
10. The process according to claim 5 , wherein the catalysts are a combination of sodium sulfite and sodium hydroxide.