Process for the distillation of a mixture comprising a cyclic N-vinylamide

Patent metadata

Field	Value
Publication number	US-9556136-B2
Application number	US-201514662890-A
Country	US
Kind code	B2
Filing date	Mar 19, 2015
Priority date	Apr 29, 2014
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A process for the distillation of a mixture which consists to at least 90% by weight of a cyclic N-vinylamide and which comprises a stabilizer, wherein
a polyether is added to the mixture before or during distillation and a product is obtained which consists to at least 99.5% by weight of the cyclic N-vinylamide.

First claim

The invention claimed is:

1. A process for the distillation of a mixture comprising a stabilizer and at least 90% by weight of a cyclic N-vinylamide based on the total weight of said mixture, the process comprising:
adding a polyether to the mixture before or during distillation to obtain a product comprising at least 99.5% by weight of the cyclic N-vinylamide and at most 10 ppm stabilizer based on the total weight of said product.

2. The process according to claim 1 , wherein the cyclic N-vinylamide is N-vinylpyrrolidone (NVP).

3. The process according to claim 1 , wherein the mixture comprises at least 98% by weight of the cyclic N-vinylamide based on the total weight of said mixture.

4. The process according to claim 1 , wherein the stabilizer is a phenol or amine type polymerization inhibitor.

5. The process according to claim 1 , wherein the stabilizer is a N, N′-di-alkyl-p-phenylendiamine.

6. The process according to claim 1 , wherein the mixture comprises from 3 to 500 ppm of the stabilizer based on the total weight of said mixture.

7. The process according to claim 1 , wherein the polyether is a polyether of formula I
R 1 O—(X—O—) n R 2

wherein R 1 and R 2 are each independently hydrogen or a hydrocarbon group with 1 to 10 C atoms, X is a straight-chain or branched C 2 -C 6 alkylene group and n is an integer of from 2 to 100.

8. The process according to claim 7 , wherein X is an ethylene or propylene group or a mixture thereof.

9. The process according to claim 7 , wherein R 1 and R 2 in formula I are each independently hydrogen or an alkyl group with 1 to 3 C atoms.

10. The process according to claim 7 , wherein R 1 and R 2 in formula I are each hydrogen.

11. The process according to claim 7 , wherein n is an integer of from 2 to 50.

12. The process according to claim 1 , wherein the process is performed in a distillation device comprising a distillation column or an evaporator and the mixture is continuously fed to the distillation device.

13. The process according to claim 12 , wherein the polyether is also fed continuously to the distillation device.

14. The process according to claim 1 , wherein 0.01 to 20 parts by weight of the polyether per 100 parts by weight of the mixture are continuously fed.

15. The process according to claim 12 , wherein a sump of the continuously operated distillation column or evaporator comprises 1 to 90% by weight of the polyether based on the total weight of the sump.

16. The process according to claim 15 , wherein a temperature of the sump is from 70 to 180° C. and a temperature of the product which is withdrawn from the distillation column is from 70 to 180° C.

17. The process according to claim 1 , wherein the distillation is performed at a pressure below 1 bar.

18. The process according to claim 1 , wherein the product comprises at least 99.9% by weight of the cyclic N-vinylamide based on the total weight of said product.

19. The process according to claim 1 , wherein the product comprises less than 5 ppm of the stabilizer based on the total weight of said product.

20. The process according to claim 1 , wherein the product comprises from 0.00001 to 0.1% by weight of acetic acid based on the total weight of said product.

21. A process for making a homo- or copolymer of a cyclic N-vinylamide, wherein said process comprises:
producing a cyclic N-vinylamide by the process according to claim 1 , and
radical polymerizing said cyclic N-vinylamide.

Assignees

• Basf Se

Inventors

• Rittinger Stefan
• Vogelsang Regina
• Fournier Pierre
• Acharya Anirudh
• Judat Sonja

Classifications

• C08F226/10

  N-Vinyl-pyrrolidone · CPC title

• C08F26/10

  N-Vinyl-pyrrolidone · CPC title

• C07D295/023 Primary

  Preparation; Separation; Stabilisation; Use of additives · CPC title