Search

US-12624000-B2 - Process for sulfonation of 2-aminoethanol hydrogen sulfate ester to produce taurine

US12624000B2US 12624000 B2US12624000 B2US 12624000B2US-12624000-B2

Abstract

A process comprises continuously adding a first stream and a second stream to a sulfonation vessel, wherein the first stream comprises aminoethanol sulfate ester (AES) and the second stream comprises an aqueous solution of sodium sulfite (Na 2 SO 3 ). The process comprises continuously mixing the AES and the aqueous solution of Na 2 SO 3 in the sulfonation vessel, thus producing a mixture. The process comprises continuously subjecting the mixture to heat in the presence of an inert gas, thus converting the AES to the taurine via sulfonation. In an aspect, the AES has a residence time of no more than four hours in the sulfonation vessel. In an aspect the heating step is conducted at a temperature of at least 115° C. and a pressure of at least 200 psi.

Inventors

  • Chi Cheng Ma
  • James Brazdil
  • Hao Luo

Assignees

  • ARCHER DANIELS MIDLAND COMPANY

Dates

Publication Date
20260512
Application Date
20210604

Claims (19)

  1. 1 . A process for continuously forming 2-aminoethanol hydrogen sulfate ester, comprising: continuously reacting monoethanolamine with sulfuric acid with at least some concurrent water removal, to provide an 2-aminoethanol hydrogen sulfate ester product; wherein the concurrent water removal is accomplished by contacting an inert particulate material with the monoethanolamine and the sulfuric acid; wherein the inert particulate material possesses the capability of receiving and removing water from the process.
  2. 2 . The process of claim 1 , further comprising removing the inert particulate material including its associated water from the process.
  3. 3 . The process of claim 1 , wherein the concurrent water removal further comprises removing water from the process by spray drying or thin film evaporation.
  4. 4 . The process of claim 3 , wherein the spray drying, or thin film evaporation follows some reaction of monoethanolamine with sulfuric acid in the presence of the inert particulate material to form 2-aminoethanol hydrogen sulfate ester.
  5. 5 . The process of claim 3 , wherein the reaction of monoethanolamine with sulfuric acid in the presence of the inert particulate material is carried out substantially in the spray dryer or thin film evaporator and water is concurrently removed by means both of the inert particulate material and the spray drying or thin film evaporation.
  6. 6 . A process for continuously producing taurine, comprising continuously forming 2-aminoethanol hydrogen sulfate ester by the process of claim 5 and continuously sulfonating the 2-aminoethanol hydrogen sulfate ester so produced to provide taurine.
  7. 7 . A process for continuously producing taurine, comprising: a) continuously adding a first stream and a second stream to a sulfonation vessel, wherein the first stream comprises an aminoethanol hydrogen sulfate ester (AES) feed and the second stream comprises an aqueous solution of sodium sulfite (Na 2 SO 3 ); b) continuously mixing the aminoethanol hydrogen sulfate ester (AES) feed and the aqueous solution of sodium sulfite (Na 2 SO 3 ) in the sulfonation vessel, thus producing a mixture; and c) continuously subjecting the mixture to heat in the presence of an inert gas, thus converting aminoethanol hydrogen sulfate ester (AES) in the feed to provide a crude taurine product via sulfonation.
  8. 8 . The process of claim 7 , wherein the aminoethanol hydrogen sulfate ester (AES) has a residence time of no more than four hours in the sulfonation vessel.
  9. 9 . The process of claim 7 , wherein the inert gas is selected from the group consisting of nitrogen, argon, helium, and combinations thereof.
  10. 10 . The process of claim 7 , further comprising subjecting the mixture to a pressure greater than autogenous pressure.
  11. 11 . The process of claim 7 , wherein the presence of the inert gas subjects the mixture to the pressure greater than autogenous pressure.
  12. 12 . The process of claim 7 , further comprising subjecting the mixture to a pressure to at least 50 psi.
  13. 13 . The process of claim 7 , wherein the heat is a temperature of at least 115° C.
  14. 14 . The process of claim 7 , wherein the aminoethanol hydrogen sulfate ester feed is continuously generated upstream of the sulfonation vessel.
  15. 15 . The process of claim 14 , further comprising separating Na 2 SO 4 and Na 2 SO 3 from the crude taurine product to provide a refined taurine product.
  16. 16 . The process of claim 15 , wherein the separating of Na 2 SO 4 and Na 2 SO 3 from the crude taurine product is performed at least in part by chromatography.
  17. 17 . The process of claim 15 , wherein the separating of Na 2 SO 4 and Na 2 SO 3 from the crude taurine product is performed at least in part by crystallization.
  18. 18 . The process of claim 7 , wherein the first stream comprising aminoethanol hydrogen sulfate ester (AES) and the second stream comprising an aqueous solution of sodium sulfite (Na 2 SO 3 ) are each degassed with an inert gas prior to being continuously added to the sulfonation vessel.
  19. 19 . The process of claim 18 , wherein the inert gas is selected from the group consisting of nitrogen, argon, helium, and combinations thereof.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry of International Application No. PCT/US21/036018, filed Jun. 4, 2021, which itself claims priority to U.S. Provisional Patent Application No. 63/035,598, filed Jun. 5, 2020, each of the contents of the entirety of which are incorporated by this reference. FIELD OF INVENTION This invention relates to a continuous process for producing taurine from aminoethanol sulfate ester, also called 2-aminoethyl hydrogen sulfate ester (AES). BACKGROUND OF THE INVENTION Taurine, also known as 2-aminoethanesulfonic acid, is an amino acid that is found in natural dietary sources, biosynthesized in the body and is also produced by chemical synthesis for commercial purposes. Taurine is sometimes referred to as a conditional amino acid because it is derived from cysteine like other amino acids but lacks a carboxyl group that usually belongs to amino acids. Instead, it contains a sulfide group and can be called an amino sulfonic acid. The world's annual consumption of taurine has been more than 50,000 tons, of which more than 80% are used as food and nutrition additives. Two methods have been used commercially to produce taurine, one method having ethylene oxide (EO) as starting material, and the other method having monoethanolamine (MEA) as starting material. In the EO method, EO is reacted with sodium bisulfite to produce sodium isethionate, which is then converted via ammonolysis to sodium taurinate. Sodium taurinate is then neutralized to produce taurine. When sodium taurinate is neutralized with sulfuric acid, then a mixture of taurine and sodium sulfate is obtained. As disclosed in U.S. Pat. No. 8,609,890, sodium taurinate may be neutralized with sulfur dioxide to obtain taurine and to regenerate sodium bisulfite. As disclosed in U.S. Pat. No. 9,145,359, one disadvantage of the EO method lies in the problematic quality of the product. More specifically, taurine produced via the EO method is a powder, and tends to form a hard cake over a short period of time during storage (in a matter of weeks), possibly due to the presence of unknown impurities. The process also involves some serious hazards from the viewpoint of safety since it uses ethylene oxide as a raw material, and ethylene oxide has extremely strong toxicity and carcinogenicity as well as posing considerable safety risks in its transport and handling. Moreover, the reaction from EO is carried out at very high temperatures (220-280° C.) and pressures (>100 bars). In a conventional method using MEA as the starting material, taurine can be prepared by reacting MEA with sulfuric acid to obtain the intermediate 2-aminoethyl hydrogen sulfate ester (AES) and then sulfonating this ester intermediate. The MEA method uses a much safer starting material and produces a needle-shaped crystalline taurine product with excellent stability during transportation and storage as compared to the taurine powder produced in the EO method. A further advantage is the mild processing conditions as compared to the high temperature and pressures as required in the EO method. A disadvantage of the MEA method on the other hand has been its higher cost of manufacture and higher capital expenditures, as compared to the EO method. A further disadvantage of the MEA method is the lengthy time required for the sulfonation stage, typically from 35-40 hours, due to the slow reaction of AES and sodium sulfite. The MEA method also typically has a low product yield in the sulfonation step. U.S. Pat. No. 9,145,359 discloses a method for the production of taurine 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 ester (AES) intermediate. The patent states that the hydrolysis of AES is accelerated under both acidic and basic conditions, and contends that the yield of taurine can be drastically increased by strictly maintaining the pH of the reaction mixture from 6.0 to 8.0 and carrying out the sulfonation reaction at a temperature of 80 to 150° C. The patent discloses examples wherein starting materials were reacted in an autoclave equipped with a stirrer for 24 hours at 110° C. under autogenous pressure for 24 hours, and examples wherein starting materials were reacted in the same autoclave for 18 hours at 120° C. U.S. Pat. No. 10,131,621 has the same named inventor as U.S. Pat. No. 9,145,359. U.S. Pat. No. 10,131,621 discloses an extraction process for recovering aminoalcohols and glycols from aqueous streams of taurine production. The aqueous streams which contain aminoalcohols and/or glycols are first mixed with a base to increase pH and then extracted with C3-C6 alcohols, ketones, and ethers. The aqueous streams are then returned to their respective cyclic process for the production of taurine. The patent states that according to the MEA process disclosed in U.S. Pat. No. 9,145,359, (i) monoethanola