Process for the preparation of succinic acid ester

Patent metadata

Field	Value
Publication number	US-9776948-B2
Application number	US-201414785794-A
Country	US
Kind code	B2
Filing date	Dec 2, 2014
Priority date	Dec 6, 2013
Publication date	Oct 3, 2017
Grant date	Oct 3, 2017

Abstract

A process for production of dialkyl succinate from bio-succinic acid feedstock where solid bio-succinic acid is fed to a reactor to react with alkanol by autocatalytic esterification. Products from the reactor including unreacted succinic acid, mono alkyl ester, dialkyl ester, alkanol, water and impurities are sent to a reaction distillation column for esterification of succinic acid and further esterification of mono alkyl ester with upflowing alkanol. The bottoms products from the reaction distillation column including residual succinic acid, mono alkyl ester, dialkyl ester, impurities and alkanol are sent to a bottoms stream separation zone where di-alkyl ester is separated from alkanol, succinic acid, mono alkyl ester and impurities. The tops products from the reaction distillation column including alkanol, water and organic components are sent to a top stream distillation zone where alkanol is separated from water and organic components. The organic components are recycled to the reaction zone column.

First claim

The invention claimed is:

1. A process for the production of dialkyl succinate from a bio-succinic acid feedstock comprising the steps of:
(a) feeding solid bio-succinic acid to a first reactor where it is contacted with alkanol, said first reactor being operated at a suitable temperature and pressure to enable autocatalytic esterification to occur;
(b) passing a stream removed from the first reactor comprising unreacted succinic acid, mono alkyl ester, dialkyl ester, alkanol, water and impurities to a point at or near the top of a reaction zone column operated at temperatures and pressures to enable esterification of the succinic acid and further esterification of the mono alkyl ester, and passing said stream in counter-current reaction to upflowing additional alkanol;
(c) removing a stream from at or near the bottom of the reaction zone column comprising components selected from residual succinic acid, mono alkyl ester, dialkyl ester, impurities and alkanol and passing said stream to a bottoms stream separation zone where said di-alkyl ester is separated from alkanol, and from the succinic acid, mono alkyl ester and impurities;
(d) recycling the succinic acid and mono alkyl ester to the reaction zone column;
(e) removing at least some of the impurities as a purge; and
(f) removing a stream comprising alkanol, water and organic components from at or near the top of the reaction zone column and passing said stream to a top stream distillation zone where the alkanol is separated, from the water and from the organic components and recycling the organic components to the reaction zone column.

2. The process according to claim 1 wherein said first reactor is a stirred tank reactor.

3. The process according to claim 2 , wherein the stirred tank reactor is operated at a temperature in the region of from about 120° C. to about 140° C.

4. The process according to claim 2 wherein the pressure within the stirred tank reactor is in the region of from about 5 bara to about 10 bara.

5. The process according to claim 1 wherein the stream from the first reactor comprising unreacted succinic acid, mono alkyl ester, dialkyl ester, alkanol, water and impurities is passed via a subsequent reaction vessel.

6. The process according to claim 5 wherein the subsequent reaction vessel is a plug flow reaction vessel.

7. The process according to claim 1 wherein the stream is passed through a distillation column before being fed to the reaction zone column.

8. The process according to claim 1 wherein the reaction zone column is operated at an overhead pressure of about 1.3 bara to about 10 bara.

9. The process according to claim 1 wherein the reaction zone column is operated at a temperature of about 100° C. to about 300° C.

10. The process according to claim 1 wherein an alkanol wash is applied at or near the top of the reaction zone column.

11. The process according to claim 1 wherein the bottoms stream separation zone is a hydrogen stripping zone.

12. The process according to claim 1 wherein the bottoms stream separation zone is a bottom stream distillation zone.

13. The process according to claim 12 wherein the bottoms stream separation zone is operated at an overhead pressure of from about 0.1 bara to about 1 bara.

14. The process according to claim 12 wherein the dialkyl succinate is removed as a liquid side draw.

15. The process according to claim 14 wherein the liquid side draw is removed from a point above the feed point to the bottoms stream distillation zone.

16. The process according to claim 1 wherein the recovered alkanol from the bottoms stream separation zone is recycled to one or both of the first reactor and the reaction zone column.

17. The process according to claim 1 wherein the residual succinic acid and any mono-ester are recycled to the reaction zone column.

18. The process according to claim 17 wherein the recycled residual succinic acid any mono-ester are recycled to the reaction zone column at a point below the point at which the feed from the first reactor is added.

19. The process according to claim 1 wherein the impurities are removed as a purge from the bottoms stream separation zone.

20. The process according to claim 1 wherein the overhead from the reaction column zone comprising alkanol, water and organic components is passed to a condenser before being passed to a top stream distillation column.

21. The process according to claim 1 wherein the top stream distillation column is operated at an overhead pressure of about 1.3 bara to about 2 bara.

22. The process according to claim 1 wherein a liquid side draw is taken from the top stream distillation column.

23. The process according to claim 22 wherein the side draw is passed to a separator to separate an aqueous phase form an organic phase.

24. The process according to claim 23 wherein the organic phase is recycled to the reaction zone column.

25. The process according to claim 23 wherein the aqueous phase is returned to the top stream distillation column.

26. The process according to claim 25 wherein the aqueous phase is returned to the column at a point below the draw point for the liquid side draw.

27. The process according to claim 1 wherein the esterification in the reaction zone column and one or both of the distillation zones can be located in separate columns.

28. The process according to claim 1 wherein the alkanol is methanol.

Assignees

• Johnson Matthey Davy Technologies Ltd

Inventors

• Smidt Martin Lucas
• Campbell Ian
• Reed Graham
• Gordon Paul
• Ferguson Christopher

Classifications

• C07C69/40

  Succinic acid esters · CPC title

• B01D3/009

  in combination with chemical reactions · CPC title

• C07C67/08 Primary

  by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds · CPC title