Process for the preparation of purified dicarboxylic acids

Patent metadata

Field	Value
Publication number	US-10654786-B2
Application number	US-201716306178-A
Country	US
Kind code	B2
Filing date	Jun 5, 2017
Priority date	Jun 6, 2016
Publication date	May 19, 2020
Grant date	May 19, 2020

Abstract

This invention relates to a process for the purification of dicarboxylic acids obtained from the hydrolysis of carboxylic acid triglycerides having more than one acid functional group. The process comprises in particular the separation of at least some of the glycerine from the hydrolysis product in an aqueous phase, evaporating and/or distilling the resultant organic phase and recovering at least some of the evaporated and/or distilled dicarboxylic acids through at least one crystallisation operation.

First claim

The invention claimed is:

1. A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue; and
d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, said step comprising the operations of:
d 1 ) extracting the organic phase evaporated and/or distilled in step c) with water in the presence of an organic solvent, obtaining an aqueous phase containing said dicarboxylic acids
d 2 ) crystallising out said dicarboxylic acids from said aqueous phase obtained in step d 1 ), wherein said step d 1 ) comprises at least one counter-current extraction operation.

2. The process according to claim 1 comprising, before step a) the steps of:
1) reacting the triglycerides of unsaturated carboxylic acid with an oxidising agent and a catalyst activating an oxidation reaction of the olefin double bond to obtain an intermediate compound containing vicinal diols,
2) reacting said intermediate compound containing vicinal diols with an oxidising agent containing molecular oxygen and a catalyst activating the oxidation reaction of the vicinal diols to carboxylic groups, obtaining monocarboxylic acids and triglycerides of carboxylic acids having more than one acid functional group; and
3) separating out a fraction of said monocarboxylic acids obtaining a mixture comprising said triglycerides of carboxylic acids having more than one acid functional group.

3. The process according to claim 1 in which the hydrolysis reaction in step a) is performed using water only at a temperature of between 240-320° C. at pressures of between 40 and 110 bar.

4. The process according to claim 3 in which said reaction is carried out at a temperature of between 260 and 310° C. at pressures of between 67 and 100 bar in one or more tubular reactors (Plug Flow Reactors).

5. The process according to claim 4 in which the ratio between the quantity of water and the starting mixture is between 1:1 and 5:1 by weight.

6. The process according to claim 1 in which said step b) comprises one or more operations selected from decanting, centrifuging, degassing, addition of water or addition of one or more organic solvents immiscible with water.

7. The process according to claim 1 in which the aqueous phase separated in step b) is further purified by means of one or more crystallization operations to recover the dicarboxylic acids contained therein.

8. The process according to claim 1 in which a fraction containing monocarboxylic acids is separated out during step c).

9. The process according to claim 1 in which any dicarboxylic acids recovered from the aqueous phase separated in step b) undergo at least one of the recovery operations in step d).

10. The process according to claim 1 in which step d 1 ) comprises:
(i) a preliminary extraction operation, performed by placing a fraction of dicarboxylic acids originating from step c) in contact with a quantity of water such as to obtain an aqueous phase/organic phase ratio of between 1:1 and 10:1 at a temperature of between 75 and 90° C., and separating out a first organic phase comprising monocarboxylic acids from a first aqueous phase comprising dicarboxylic acids; and
(ii) a second extraction operation, performed by placing said first aqueous phase comprising dicarboxylic acids in contact with an organic solvent and separating out a second organic phase comprising monocarboxylic acids from a second aqueous phase comprising dicarboxylic acid.

11. The process according to claim 1 in which at least part of the crystallisation mother liquors separated out in step d 2 ) of the process are recycled to hydrolysis step a).

12. A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue; and
d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, said step comprising at least one melt crystallisation of said dicarboxylic acids.

13. The process according to claim 12 in which said recovery step d) comprises fractional suspension crystallisation.

14. A process for the preparation of purified dicarboxylic acids from a mixture containing triglycerides of carboxylic acids having more than one acid functional group comprising the steps of:
a) hydrolysing said mixture containing triglycerides in the presence of water, obtaining a reaction product comprising dicarboxylic acids and glycerine;
b) separating out an aqueous phase comprising at least a part of the glycerine from the remaining reaction product from step a) organic phase;
c) evaporating and/or distilling the organic phase obtained from step b), separating out a residue; and
d) recovering at least a part of the dicarboxylic acids from the organic phase evaporated and/or distilled in step c) by means of at least one crystallisation operation, wherein the triglycerides of carboxylic acids mainly comprise azelaic acid and higher dicarboxylic acids and said recovery step d) comprises at least one crystallisation of said dicarboxylic acids from an organic solvent selected from aliphatic hydrocarbons.

15. The process according to claim 2 in which the hydrolysis reaction in step a) is performed using water only at a temperature of between 240-320° C. at pressures of between 40 and 110 bar.

16. The process according to claim 2 in which said step b) comprises one or more operations selected from decanting, centrifuging, degassing, addition of water or addition of one or more organic solvents immiscible with water.

17. The process according to claim 3 in which said step b) comprises one or more operations selected from decanting, centrifuging, degassing, addition of water or addition of one or more organic solvents immiscible with water.

18. The process according to claim 4 in which said step b) comprises one or more operations selected from decanting, centrifuging, degassing, addition of water or addition of one or more organic solvents immiscible with water.

19. The process according to claim 5 in which said step b) comprises one or more operations selected from decanting, centrifuging, degassing, addition of water or addition of one or more organic solvents immiscible with water.

20. The process according to claim 2 in which the aqueous phase separated in step b) is further purified by means of one or more crystallization operations to recover the dicarboxylic acids contained therein.

Assignees

• Novamont Spa

Inventors

• Capuzzi Luigi
• Digioia Francesca

Classifications

• C07C55/18

  Azelaic acid · CPC title

• C07C69/48

  Azelaic acid esters · CPC title

• C11C1/04

  by hydrolysis · CPC title

• C07C51/09

  from carboxylic acid esters or lactones · CPC title

• C07C67/333

  by isomerisation; by change of size of the carbon skeleton (introduction or elimination of carboxyl groups C07C67/313, C07C67/32) · CPC title