Method for producing 2-acrylamido-2-methylpropane sulphonic acid

Patent metadata

Field	Value
Publication number	US-10669231-B2
Application number	US-201816495207-A
Country	US
Kind code	B2
Filing date	Mar 19, 2018
Priority date	Mar 20, 2017
Publication date	Jun 2, 2020
Grant date	Jun 2, 2020

Abstract

The present invention relates to a production process for 2-acrylamido-2-methylpropane sulfonic acid including at least the following successive steps:
1) mixing of acrylonitrile with at least one compound contributing SO 3 at a temperature included between −80 and 30° C.; 2) placing in contact and mixing isobutylene and the sulfonating mixture with a molar ratio of SO 3 to isobutylene included between 0.2:1 and 2:1 and a molar ratio of acrylonitrile to isobutylene included between 3:1 and 60:1 at a temperature included between −40 and 100° C.; 3) solid/liquid separation of the reaction mixture and isolation of the solid particles in the form of a composition 1; 4) mixing composition 1 at the end of step 3) with an aqueous solution A included at a temperature comprised between −20 and 70° C. in order to obtain a suspension 1 of 2-acrylamido-2-methylpropane sulfonic acid crystals; 5) solid/liquid separation of the suspension 1 and isolation of the crystals in form of composition 2.

First claim

The invention claimed is:

1. A production process for 2-acrylamido-2-methylpropane sulfonic acid including at least the following successive steps:
1) mixing of acrylonitrile with at least one compound contributing SO 3 at a temperature included between −80 and 30° C. for at least one second in order to obtain a sulfonating mixture;
2) placing in contact and mixing isobutylene and the sulfonating mixture with a molar ratio of SO 3 to isobutylene included between 0.2:1 and 2:1 and a molar ratio of acrylonitrile to isobutylene included between 3:1 and 60:1 at a temperature included between −40 and 100° C. for a time included between 10 seconds and 300 minutes in order to obtain a reaction mixture;
3) solid/liquid separation of the reaction mixture and isolation of the solid particles contained in the reaction mixture in the form of a composition 1 in which the solid particles represent 50 to 99% by weight of the composition 1;
4) mixing composition 1 at the end of step 3) with an aqueous solution A for at least 10 minutes at a temperature included between −20 and 70° C. in order to obtain a suspension 1 of 2-acrylamido-2-methylpropane sulfonic acid crystals;
5) solid/liquid separation of the suspension 1 and isolation of the crystals in the form of a composition 2 in which the crystals represent between 40 and 99% by weight of the composition 2.

2. The process according to claim 1 , wherein the compound contributing SO 3 is fuming sulfuric acid, used at a concentration included between 100% and 113.5%.

3. The process according to claim 1 , wherein step 1) includes mixing acrylonitrile with at least one compound contributing SO 3 in a solvent 1.

4. The process according to claim 3 , wherein the solvent 1 is acrylonitrile.

5. The process according to claim 1 , wherein isobutylene is added, during step 2), dissolved in a solvent 2.

6. The process according to claim 1 , wherein the molar ratio of SO 3 to isobutylene from step 2) is included between 0.4:1 and 1.5:1.

7. The process according to claim 5 , wherein 2-acrylamido-2-methylpropane sulfonic acid particles are concentrated in the reaction mixture by evaporation of solvents 1 and 2 before the solid/liquid separation step.

8. The process according to claim 1 , wherein the ratio by weight of aqueous solution A mixed, during step 4), with the composition 1 from step 3) is included between 0.05:1 and 1:1.

9. The process according to claim 1 , wherein composition 1 is washed with a solvent 3.

10. The process according to claim 1 , wherein the aqueous solution A of step 4) includes up to 20% of organic solvent 4.

11. The process according to claim 10 , wherein the organic solvent 4 is acrylonitrile.

12. The process according to claim 1 , wherein the aqueous solution A from step 4) includes at least 80% by weight of water and up to 20% by weight of inorganic acid.

13. The process according to claim 12 , wherein the inorganic acid is sulfuric acid.

14. The process according to claim 1 , wherein the liquid phase resulting at the end of the solid/liquid separation of the suspension 1 in step 5) serves wholly or partially as aqueous solution A in step 4).

15. The process according to claim 1 , wherein the composition 2 of step 5) is washed using a washing solution.

16. The process according to claim 3 , wherein the solvent 1 is chosen from the group including acetic anhydride, carboxylic acids, acetic acid, nitriles, alcohols, amines, alkanes, amides, ethers, aromatics, alkylsulfonic acids and the liquid phase resulting from the liquid/solid separation from step 3).

17. The process according to claim 5 , wherein the solvent 2 is selected from acrylonitrile and the liquid phase resulting from the liquid/solid separation from step 3).

18. The process according to claim 6 , wherein the molar ratio of SO 3 to isobutylene from step 2) is included between 0.7:1 and 1.2:1.

19. The process according to claim 8 , wherein the ratio by weight of aqueous solution A mixed, during step 4), with the composition 1 from step 3) is included between 0.15:1 and 0.9:1.

20. The process according to claim 1 wherein:
composition 1 is washed with a solvent 3, which is an acrylonitrile solution;
the aqueous solution A of step 4) includes: from 2 to 10% of organic solvent 4, wherein the organic solvent 4 is acrylonitrile; between 85% and 98% by weight of water; and 2% to 15% by weight of inorganic acid, wherein the organic acid is sulfuric acid; and
the composition 2 of step 5) is washed using a washing solution, which is an aqueous solution including up to 20% by weight of organic solvent 4.

Assignees

• Spcm Sa

Inventors

• Favero Cédrick
• Kieffer Johann

Classifications

• C07C303/20 Primary

  by addition of sulfurous acid or salts thereof to compounds having carbon-to-carbon multiple bonds · CPC title

• C07C309/15

  the nitrogen atom of at least one of the amino groups being part of any of the groups [IMAGE cpc-sch-C07C-0975.gif], X being a hetero atom, Y being any atom · CPC title

• C07C303/44

  Separation; Purification · CPC title

• C07C303/02 Primary

  of sulfonic acids or halides thereof · CPC title

• C07C309/21

  containing nitrogen atoms, not being part of nitro or nitroso groups, bound to the carbon skeleton · CPC title