Process for making and refining 3-pentenenitrile, and for refining 2-methyl-3-butenenitrile

1. An integrated, continuous process for the production of 3-pentenenitrile, the refining of 3-pentenenitrile, and the refining of 2-methyl-3-butenenitrile, the process comprising:

(a) contacting, in a reaction zone, a hydrogen cyanide-containing feed, a 1,3-butadiene-containing feed, and a catalyst composition, wherein the catalyst composition comprises a zero-valent nickel and at least one bidentate phosphorus-containing ligand selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, a mixed phosphorus-containing ligand, and combinations thereof;

(b) maintaining a residence time in the reaction zone sufficient to convert about 95% or more of the hydrogen cyanide and to produce a reaction mixture comprising 3-pentenenitrile and 2-methyl-3-butenenitrile, wherein the 2-methyl-3-butenenitrile concentration is maintained below about 15 weight percent of the total mass of the reaction mixture;

(c) distilling the reaction mixture to obtain a first stream comprising 1,3-butadiene, a second stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a third stream comprising the catalyst composition;

(d) distilling the second stream to obtain a fourth stream comprising 1,3-butadiene, a fifth stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a sixth stream comprising 3-pentenenitrile; and

(e) distilling the fifth stream to obtain a seventh stream comprising 1,3-butadiene, an eighth stream comprising (Z)-2-methyl-2-butenenitrile, and a ninth stream comprising 2-methyl-3-butenenitrile.

2. The process of claim 1 , wherein at least one distilling process separately obtains a combination stream and an additional stream; wherein

the distilling process is selected from the group consisting of (c) distilling the reaction mixture, (d) distilling the second stream, (e) distilling the fifth stream, and combinations thereof;

the combination stream is introduced into at least one partial condenser to obtain a vapor stream and a liquid stream;

when the distilling process is (c) distilling the reaction mixture, the combination stream is stream A, the vapor stream obtained from stream A is the first stream comprising 1,3-butadiene, the liquid stream obtained from stream A is the second stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and the additional stream is the third stream;

when the distilling process is (d) distilling the second stream, the combination stream is stream B, the vapor stream obtained from stream B is the fourth stream comprising 1,3-butadiene, the liquid stream obtained from stream B is the fifth stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and the additional stream is the sixth stream; and

when the distilling process is (e) distilling the fifth stream, the combination stream is stream C, the vapor stream obtained from stream C is the seventh stream comprising 1,3-butadiene, the liquid stream obtained from stream C is the eighth stream comprising (Z)-2-methyl-2-butenenitrile, and the additional stream is the ninth stream.

3. The process of claim 1 , wherein (c) distilling the reaction mixture obtains a stream A and the third stream; and stream A is introduced into at least one partial condenser to obtain the first stream as a vapor stream comprising 1,3-butadiene and the second stream as a liquid stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene.

4. The process of claim 1 , wherein (d) distilling the second stream obtains a stream B and the sixth stream; and stream B is introduced into at least one partial condenser to obtain the fourth stream as a vapor stream comprising 1,3-butadiene and the fifth stream as a liquid stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene.

5. The process of claim 1 , wherein (e) distilling the fifth stream obtains a stream C and the ninth stream; and stream C is introduced into at least one partial condenser to obtain the seventh stream as a vapor stream comprising 1,3-butadiene and the eighth stream as a liquid stream comprising (Z)-2-methyl-2-butenenitrile.

6. The process of claim 1 , wherein

distilling the reaction mixture obtains a stream A and the third stream;

stream A is introduced into at least one partial condenser to obtain the first stream as a vapor stream comprising 1,3-butadiene and the second stream as a liquid stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene;

distilling the second stream obtains a stream B and the sixth stream;

stream B is introduced into at least one partial condenser to obtain the fourth stream as a vapor stream comprising 1,3-butadiene and the fifth stream as a liquid stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene;

distilling the fifth stream obtains a stream C and the ninth stream; and

stream C is introduced into at least one partial condenser to obtain the seventh stream as a vapor stream comprising 1,3-butadiene and the eighth stream as a liquid stream comprising (Z)-2-methyl-2-butenenitrile.

7. The process of claim 1 or claim 2 , wherein at least a portion of the ninth stream comprising 2-methyl-3-butenenitrile is returned to the reaction zone.

8. The process of claim 1 or claim 2 , wherein at least a portion of the first stream, the fourth stream, the seventh stream, or combinations thereof is returned to the reaction zone.

9. The process of claim 1 or claim 2 , wherein at least one of the first stream, the fourth stream, or the seventh stream further comprises butene, and at least a portion of the first stream, the fourth stream, the seventh stream, or combinations thereof is withdrawn to purge at least a portion of the butene prior to returning the stream to the reaction zone.

10. The process of claim 1 or claim 2 , wherein the total butene content of at least one of the first stream, the fourth stream, or the seventh stream is greater than about 20 percent by weight.

11. The process of claim 1 or claim 2 , wherein at least a portion of the ninth stream comprising 2-methyl-3-butenenitrile is contacted with at least a portion of the first stream comprising 1,3-butadiene to produce a recycle stream comprising 2-methyl-3-butenenitrile and 1,3-butadiene, and the recycle stream is returned to the reaction zone.

12. The process of claim 1 or claim 2 , wherein at least a portion of the third stream comprising the catalyst composition is returned to the reaction zone.

13. The process of claim 1 or claim 2 , wherein at least a portion of the sixth stream comprising 3-pentenenitrile is hydrocyanated to produce a dinitrile product comprising adiponitrile.

14. The process of claim 1 or claim 2 , wherein the 1,3-butadiene-containing feed comprises 1,3-butadiene which has been distilled to remove an impurity selected from the group consisting of 4-tert-butylcatechol, 4-vinyl-1-cyclohexene, and combinations thereof.

15. The process of claim 1 or claim 2 , wherein the reaction mixture is distilled in at least one distillation column at less than one atmosphere pressure and with a base temperature of about 120° C. or less.

16. The process of claim 1 or claim 2 , wherein the second stream is distilled in at least one distillation column at or above one atmosphere pressure and wherein the sixth stream contains less than about 1.0 percent by weight 2-methyl-3-butenenitrile.

17. The process of claim 1 or claim 2 , wherein the fifth stream is distilled in at least one distillation column and wherein the fifth stream is introduced to the rectifying section of the column.

18. The process of claim 1 or claim 2 , wherein the temperature is maintained within a range of about 80° C. to about 140° C.

19. The process of claim 1 or claim 2 , wherein the molar ratio of the hydrogen cyanide in the feed to the 1,3-butadiene in the feed is in the range of about 0.90:1.00 to about 1.04:1.00,and the molar ratio of the zero-valent nickel in the feed to the 1,3-butadiene in the feed is in the range of about 0.00005:1.00 to about 0.0050:1.00.

20. The process of claim 1 or claim 2 , wherein the bidentate phosphorus-containing ligand is a phosphite ligand selected from a member of the group represented by Formula XXXIII and Formula XXXIV:

wherein R 41 and R 45 are independently selected from the group consisting of C 1 to C 5 hydrocarbyl, and each of R 42 , R 43 , R 44 , R 46 , R 47 and R 48 is independently selected from the group consisting of H and C 1 to C 4 hydrocarbyl.

21. The process of claim 1 or claim 2 or claim 20 , wherein the catalyst composition further comprises at least one monodentate phosphite ligand.

22. An integrated, continuous process for the production of 3-pentenenitrile, the refining of 3-pentenenitrile, and the refining of 2-methyl-3-butenenitrile, the process comprising:

(a) contacting, in a reaction zone, a hydrogen cyanide-containing feed, a 1,3-butadiene-containing feed, and a catalyst composition, wherein the catalyst composition comprises a zero-valent nickel and at least one bidentate phosphite ligand selected from a member of the group represented by Formulas XXXIII and XXXIV:

wherein R 41 and R 45 are independently selected from the group consisting of C 1 to C 5 hydrocarbyl, and each of R 42 , R 43 , R 44 , R 46 , R 47 and R 48 is independently selected from the group consisting of H and C 1 to C 4 hydrocarbyl;

(b) maintaining a residence time in the reaction zone sufficient to convert about 95% or more of the hydrogen cyanide and to produce a reaction mixture comprising 3-pentenenitrile and 2-methyl-3-butenenitrile, wherein the 2-methyl-3-butenenitrile concentration is maintained below about 15 weight percent of the total mass of the reaction mixture;

(c) distilling the reaction mixture to obtain a first overhead stream comprising 1,3-butadiene, a first side-draw stream comprising 3-pentenenitrile, 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a first bottom stream comprising the catalyst composition;

(d) distilling the first side-draw stream to obtain a second overhead stream comprising 1,3-butadiene, a second side-draw stream comprising 2-methyl-3-butenenitrile, (Z)-2-methyl-2-butenenitrile, and optionally 1,3-butadiene, and a second bottom stream comprising 3-pentenenitrile;

(e) distilling the second side-draw stream to obtain a third overhead stream comprising 1,3-butadiene, a third side-draw stream comprising (Z)-2-methyl-2-butenenitrile, and a third bottom stream comprising 2-methyl-3-butenenitrile;

(f) returning at least a portion of the first overhead stream, the second overhead stream, the third overhead stream, or combinations thereof to the reaction zone; and

(g) returning at least a portion of the third bottom stream to the reaction zone.

23. The process of claim 22 , wherein the catalyst composition further comprises at least one monodentate phosphite ligand.