Cyclic process for the production of taurine from monoethanolamine

Abstract

A method is disclosed for the production of taurine in high yield by a cyclic process of reacting monoethanolamine, sulfuric acid, and ammonium sulfite in the presence of additives to inhibit the hydrolysis of 2-aminoethyl hydrogen sulfate intermediate. The cyclic process is economical and little waste is generated.

What is claimed is: 
     
       1. A cyclic process for increasing the overall production yield of taurine from monoethanolamine, comprising:
 (a) Reacting monoethanol amine with sulfuric acid to form 2-aminoethyl hydrogen sulfate ester;   (b) Carrying out the reaction of 2-aminoethylhydrogen sulfate ester with ammonium sulfite to yield taurine in a buffering system at pH 6.0 to 8.0;   (c) Suppressing the hydrolysis of 2-aminoethyl hydrogen sulfate ester during its reaction with ammonium sulfite by use of hydrolysis inhibitors;   (d) Converting the residual monoethanolamine in the crystallization mother liquor of taurine to 2-aminoethyl hydrogen sulfate ester, which is recycled to step (a) to produce taurine.   
     
     
       2. The process according to  claim 1 , wherein the buffering system is composed of ammonium bisulfite and excess ammonium sulfite. 
     
     
       3. The process according to  claim 1 , wherein hydrolysis inhibitors are monoethanolamine, diethanolamine, triethanolamine, and dimethylaminoethanol. 
     
     
       4. The process according to  claim 1 , wherein the residual monoethanolamine in the crystallization mother liquor of taurine is reacted with sulfuric acid in the presence of ammonium sulfate to regenerate 2-aminoethyl hydrogen sulfate ester intermediate. 
     
     
       5. A cyclic process for increasing the overall production yield of taurine from monoethanolamine, comprising:
 (a) reacting monoethanolamine and sulfuric acid to form 2-aminoethyl hydrogen sulfate ester;   (b) carrying out a sulfonation reaction of the 2-aminoethyl hydrogen sulfate ester with ammonium sulfite to yield taurine and ammonium sulfate in a buffering solution comprising the recycled mother liquor solution from step (c) in the presence of at least one hydrolysis inhibitor for the 2-aminoethyl hydrogen sulfate ester at pH 6.0 to 8.0;   (c) separating the taurine and the ammonium sulfate from step (b) by crystallization and solid-liquid separation to yield a mother liquor solution;   (d) recycling the mother liquor solution of step (c) to step (b), and optionally bleeding the mother liquor solution of step (c) to step (e); and   (e) adding sulfuric acid to the bleeding mother solution of step (d) to convert the residual monoethanolamine to 2-aminoethyl hydrogen sulfate ester, which is recycled to step (b).    
     
     
       6. The process according to claim 5, wherein the buffering solution is comprised of ammonium bisulfite and ammonium sulfite.  
     
     
       7. The process according to claim 5, wherein the hydrolysis inhibitor is selected from the group consisting of monoethanolamine, diethanolamine, triethanolamine, dimethylaminoethanol, and a mixture thereof.  
     
     
       8. The process according to claim 5, wherein the hydrolysis inhibitor is monoethanolamine.  
     
     
       9. The process according to claim 5, wherein the hydrolysis inhibitor is monoethanolamine in the recycled mother liquor solution.  
     
     
       10. The process according to claim 5, wherein the mother liquor solution is comprised of monoethanolamine.  
     
     
       11. The process according to claim 5, wherein the sulfonation reaction is carried out at a temperature from 90° C. to 150° C.