INHIBITING CPI FORMATION FROM ADIPONITRILE

• US 20180244607A1
• Filed: 08/31/2016
• Published: 08/30/2018
• Est. Priority Date: 09/03/2015
• Status: Active Grant

• Current Assignee: INV Nylon Chemicals Americas LLC
• Original Assignee: Invista North America Sarl (Invista)
• Inventors: TENN, III, WILLIAM J.
• Granted Patent: US 10,640,459 B2
• Time in Patent Office: Days
• CPC Class Codes: B01D 3/143 by two or more of a fractionation, separation or rectification step
• CPC Class Codes: B01D 3/34 with one or more auxiliary substances
• CPC Class Codes: C07C 253/34 Separation; Purification
• CPC Class Codes: C07C 255/04 containing two cyano groups bound to the carbon skeleton

Abstract

Disclosed is a method for inhibiting the formation of by-products from dinitriles, such as the formation of cyclopentylideneimine (CPI) from Adiponitrile (ADN), comprising adding an effective amount of a Brønsted acid to the ADN. Also disclosed is a method of refining a dinitrile compound by distillation the method comprising the steps of: (a) supplying (i) a feedstream comprising the dinitrile compound and (ii) a Brønsted acid to a distillation apparatus; and (b) withdrawing from the distillation apparatus an overhead distillate stream comprising the dinitrile compound.

Claims

1. A method of refining a dinitrile compound by distillation the method comprising the steps of:

(a) supplying (i) a feedstream comprising the dinitrile compound and (ii) a Brø

nsted acid to a distillation apparatus; and

(b) withdrawing from the distillation apparatus an overhead distillate stream comprising the dinitrile compound.

2. A method according to claim 1, wherein the dinitrile compound is selected from dinitrile compounds of the formula (I):

NC—

R¹—

CN 

 

(I)

wherein R¹ represents a C₁ to C₁₀ straight chain or branched alkylene group, optionally wherein R¹ represents a C₂ to C₈ straight chain or branched alkylene group, or a C₂ to C₆ straight chain or branched alkylene group, or a C₂ to C₄ straight chain or branched alkylene group.

3. A method according to claim 2, wherein the dinitrile compound is ADN.

4. A method according to claim 3, wherein the dinitrile-containing feedstream comprises a Lewis acid.

5. A method according to claim 4, wherein the Lewis acid is selected from ZnX₂, BX₃ and AlX₃, wherein X represents a halogen, trifluoromethanesulfonate, methanesulfonate or toluenesulfonate, preferably wherein the Lewis acid is selected from ZnCl₂, BCl₃ or AlCl₃.

6. A method according to claim 4, wherein the amount of Lewis acid present in the dinitrile-containing feedstream is in the range of from 50 to 10,000 ppm by weight based on the total weight of the dinitrile-containing feedstream.

7. A method according to claim 6, wherein the feedstream to the distillation apparatus in step (a) comprises a reaction effluent from a process for the production of dinitriles via the hydrocyanation of unsaturated mononitriles.

8. A method according to claim 7, wherein the feedstream to the distillation apparatus in step (a) comprises a reaction effluent from a process for the production of ADN via the hydrocyanation of 3PN.

9. A method according to claim 8 wherein the reaction effluent comprises a nickel (0) catalyst stabilized with phosphorus-containing ligands and/or excess phosphorus-containing ligands.

10. A method according to claim 9, wherein the Brø

nsted acid is selected from phosphoric acids, sulfuric acid, C₄ to C₁₂ alkanesulfonic acids and C₇ to C₁₈ alkylbenzenesulfonic acids.

11. A method according to claim 10, wherein the Brø

nsted acid is selected from phosphoric acid, polyphosphoric acid, pyrophosphoric acid, octanesulfonic acid, decanesulfonic acid, dodecanesulfonic acid, 4-toluenesulfonic acid, 4-ethylbenzenesulfonic acid, 4-butylbenzenesulfonic acid and 4-dodecylbenzenesulfonic acid.

12. A method according to claim 11, wherein the Brø

nsted acid is supplied to the distillation apparatus in an amount of from 5 to 5,000 ppm by weight, based on the total weight of the dinitrile-containing feedstream and the Brø

nsted acid.

13. A method according to claim 12, wherein the Brø

nsted acid is withdrawn from the distillation apparatus in a bottoms stream.

14. A method according to claim 13, wherein the distillation apparatus is operated with a bottoms temperature in the range of from 20 to 300°

C., more preferably in the range of from 50 to 250°

C., more preferably from 80 to 200°

C.

15. A method according to claim 14, wherein the distillation apparatus comprises a plurality of distillation columns and wherein the Brø

nsted acid is supplied to at least one of the distillation columns, optionally wherein the Brø

nsted acid is supplied to each of the distillation columns.

16. A method for inhibiting the formation of by-products from a dinitrile compound, the method comprising adding an effective amount of a Brø

nsted acid to the dinitrile compound.

17. A method according to claim 16, wherein the dinitrile compound selected from the dinitrile compounds of the formula (I):

NC—

R¹—

CN 

 

(I)

wherein R¹ represents a C₁ to C₁₀ straight chain or branched alkylene group, optionally wherein R¹ represents a C₂ to C₈ straight chain or branched alkylene group, or a C₂ to C₆ straight chain or branched alkylene group, or a C₂ to C₄ straight chain or branched alkylene group.

18. A method according to claim 17, for inhibiting the formation of CPI from ADN.

19. A method according to claim 16, comprising refining the dinitrile compound by distillation, wherein (i) a feedstream comprising the dinitrile compound and (ii) the Brø

nsted acid are supplied to a distillation apparatus; and

an overhead distillate stream comprising the dinitrile compound is withdrawn from the distillation apparatus.

20. A method according to claim 19, wherein the dinitrile compound is separated from the Brø

nsted acid by distillation.

22. A method according to claim 16, wherein an effective amount of the Brø

nsted acid is defined as from 5 to 5,000 ppm by weight, optionally from 5 to 1,000 ppm by weight, optionally from 10 to 500 ppm by weight, based on the total weight of the composition comprising the dinitrile and the Brø

nsted acid.

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