Enhanced extraction of impurities from mixture comprising nitriles

Patent metadata

Field	Value
Publication number	US-9914700-B2
Application number	US-201515320898-A
Country	US
Kind code	B2
Filing date	Jun 25, 2015
Priority date	Jun 27, 2014
Publication date	Mar 13, 2018
Grant date	Mar 13, 2018

Abstract

Disclosed herein are methods for recovering phosphorus-containing ligand from mixtures comprising organic mononitriles and organic dinitriles, using liquid-liquid extraction. Also disclosed are treatments to enhance extractability of the phosphorus-containing ligand.

First claim

What is claimed is:

1. A process for recovering a catalyst and adiponitrile (ADN) from a mixture comprising adiponitrile, 3-pentenenitrile (3PN), a Lewis acid and a catalyst, said process comprising the steps of:
(a) providing a countercurrent multistage extraction zone comprising at least three mixer-settlers connected in series;
(b) introducing said mixture comprising ADN, 3PN, Lewis acid and a catalyst to a first terminal mixer-settler in the series;
(c) introducing an extraction solvent into the second terminal mixer-settler in the series;
(d) forming a light phase comprising extraction solvent and a heavy phase comprising ADN and 3PN in the settling sections of each of the mixer-settlers;
(e) flowing the heavy phase progressively from the first terminal mixer-settler through each of the mixer-settlers and into the second terminal mixer-settler;
(f) flowing the light phase progressively from the second terminal mixer-settler through each of the mixer-settlers and into the first terminal mixer-settler;
(g) withdrawing the light phase comprising extraction solvent and extracted catalyst from the first terminal mixer-settler;
(h) withdrawing the heavy phase comprising ADN and 3PN from the second terminal mixer-settler;
(i) distilling the withdrawn light phase from step (g) to separate extraction solvent from catalyst; and
(j) distilling the withdrawn heavy phase from step (h) to separate ADN from 3PN,
wherein the catalyst comprises zero valent nickel and a phosphorus-containing ligand,
wherein a polyamine is added to the mixing section of the first terminal mixer-settler to form a precipitate comprising a complex of the Lewis acid with the polyamine,
wherein the precipitate is dispersed in the heavy phase in the settling section of the first mixer-settler,
wherein the precipitate is entrained in the flow of heavy phase through the series of mixer-settlers, and
wherein the precipitate is withdrawn from the second terminal mixer-settler, along with the heavy phase.

2. The process of claim 1 , wherein the complex of Lewis acid and polyamine formed in the mixing section of the first terminal mixer-settler is capable of catalyzing the cyclization reaction of ADN to form 2-cyanocyclopentylideneimine (CPI).

3. The process of claim 1 , further comprising the steps of:
(k) removing precipitate comprising a complex of the Lewis acid with the polyamine from the heavy phase withdrawn in step (h), followed by
(l) separating ADN from 3PN.

4. The process of claim 1 , wherein the catalyst comprises a bidentate phosphite ligand or a bidentate phosphonite ligand.

5. The process of claim 1 , wherein the Lewis acid is ZnCl 2 .

6. The process of claim 1 , wherein the catalyst comprises a diphosphite ligand of the formula:

wherein in I, II and Ill, R 1 is phenyl, unsubstituted or substituted with one or more C 1 to C 12 alkyl or C 1 to C 12 alkoxy groups; or naphthyl, unsubstituted or substituted with one or more C 1 to C 12 alkyl or C 1 to C 12 alkoxy groups; and wherein Z and Z 1 are independently selected from the group consisting of structural formulae IV, V, VI, VII, and VIII:

and wherein
R 2 , R 3 , R 4 , R 5 , R 6 , R 7 , R 8 , and R 9 are independently selected from the group consisting of H, C 1 to C 12 alkyl, and C 1 to C 12 alkoxy;
X is O, S, or CH(R 10 );
R 10 is H or C 1 to C 12 alkyl;

and wherein
R 11 and R 12 are independently selected from the group consisting of H, C 1 to C 12 alkyl, and C 1 to C 12 alkoxy and CO 2 R 13 ,
R 13 is C 1 to C 12 alkyl, or C 6 to C 10 aryl unsubstituted or substituted with C 1 to C 4 alkyl;
Y is O, S, or CH(R 14 );
R 14 is H or C 1 to C 12 alkyl;

wherein
R 15 is selected from the group consisting of H, C 1 to C 12 alkyl, and C 1 to C 12 alkoxy and CO 2 R 16 ,
R 16 is C 1 to C 12 alkyl, or C 6 to C 10 aryl, unsubstituted or substituted with C 1 to C 4 alkyl,
and wherein

for structural formulae I through VIII, the C 1 to C 12 alkyl, and C 1 to C 12 alkoxy groups may be straight chain or branched.

7. The process of claim 1 , wherein the catalyst comprises a diphosphonite ligand of the formula:
(R 1 )(R 2 —O)P—O—Y—O—P(O—R 3 )(R 4 )   L

where R 1 and R 2 are each independently identical or different, separate or bridged organic radicals; R 3 and R 4 are each independently identical or different, separate or bridged organic radicals; and Y is a bridging group.

8. The process of claim 1 , wherein the extraction solvent feed from the second stage comprises at least 1000 ppm of diphosphite-containing ligand or diphosphonite-containing ligand.

9. The process of claim 1 , wherein at least one stage of the extraction is carried out above 40° C.

10. The process of claim 1 , wherein the extraction solvent is cyclohexane.

11. The process of claim 1 wherein the feed mixture is an effluent stream from a hydrocyanation process.

12. The process of claim 11 wherein the hydrocyanation process includes a 3-pentenenitrile hydrocyanation process.

13. The process of claim 11 wherein the hydrocyanation process includes a 1,3-butadiene hydrocyanation process.

14. The process of claim 1 , wherein the polyamine is selected from the group consisting of hexamethylene diamine, bis-hexamethylene triamine and 1,2-diaminocyclohexane.

15. The process of claim 1 , wherein bis-hexamethylene triamine is added to the mixing section of the first terminal mixer-settler.

Assignees

• Invista North America Sarl

Inventors

• Tenn Iii William J

Classifications

• B01J31/185

  Phosphites ((RO)3P) , their isomeric phosphonates (R(RO)2P=O) and RO-substitution derivatives thereof · CPC title

• B01J2531/002

  Materials · CPC title

• B01D3/12

  Molecular distillation · CPC title

• B01J38/04

  Gas or vapour treating; Treating by using liquids vaporisable upon contacting spent catalyst · CPC title

• C07C253/34 Primary

  Separation; Purification · CPC title