Process for making 3-pentenenitrile by hydrocyanation of butadiene
View Patent ↗The invention provides a continuous process for the production of 3-pentenenitrile comprising: (a) contacting, in a reaction zone, a hydrogen cyanide-containing feed, a butadiene-containing feed, and a catalyst precursor composition, wherein the catalyst precursor composition comprises a zero-valent nickel and at least one bidentate phosphite ligand selected from a member of the group represented by Structures I and II, in which all like reference characters have the same meaning, except as further explicitly limited: wherein R 1 and R 5 are independently selected from the group consisting of C 1 to C 5 hydrocarbyl, and R 2 , R 3 , R 4 , R 6 , R 7 and R 8 are independently selected from the group consisting of H and C 1 to C 4 hydrocarbyl; and (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.
1. A process for the continuous production of 3-pentenenitrile, comprising:
(a) continuously introducing feed comprising hydrogen cyanide, 1,3-butadiene, and a catalyst precursor composition in a reaction zone, 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, wherein the catalyst precursor composition comprises a zero-valent nickel and at least one bidentate phosphite selected from a member of the group represented by Structures I and II:
wherein R 1 and R 5 are independently selected from the group consisting of C 1 to C 5 hydrocarbyl, and R 2 , R 3 , R 4 , R 6 , R 7 and R 8 are independently selected from the group consisting of H and C 1 to C 4 hydrocarbyl;
(b) displacing a product mixture from the reaction zone by the feed which is continuously introduced into the reaction zone; and
(c) maintaining a residence time in the reaction zone sufficient to convert about 95% or more of the hydrogen cyanide and to produce the product mixture, wherein the product mixture comprises 3-pentenenitrile and 2-methyl-3-butenenitrile, and wherein the 2-methyl-3-butenenitrile concentration is maintained below about 15 weight percent of the total mass of the product mixture.
2. The process according to claim 1 , wherein 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.
3. The process according to claim 1 , wherein the temperature is maintained within a range of about 80° C. to about 140° C.
4. The process according to claim 1 , wherein the bidentate phosphite ligand is selected from a member of the group represented by Structures I and II, wherein
R 1 is methyl, ethyl, isopropyl or cyclopentyl;
R 2 is H or methyl;
R 3 is H or a C 1 to C 4 hydrocarbyl;
R 4 is H or methyl;
R 5 is methyl, ethyl or isopropyl; and
R 6 , R 7 and R 8 are independently selected from the group consisting of H and C 1 to C 4 hydrocarbyl.
5. The process according to claim 1 , wherein the bidentate phosphite ligand is selected from a member of the group represented by Structure I, wherein
R 1 , R 4 , and R 5 are methyl;
R 2 , R 6 , R 7 and R 8 are H; and
R 3 is a C 1 to C 4 hydrocarbyl.
6. The process according to claim 1 , wherein the bidentate phosphite ligand is selected from a member of the group represented by Structure I, wherein
R 1 is isopropyl;
R 2 is H;
R 3 is a C 1 to C 4 hydrocarbyl;
R 4 is H or methyl;
R 5 is methyl or ethyl;
R 6 and R 8 are H or methyl; and
R 7 is H, methyl or tertiary-butyl.
7. The process according to claim 1 , wherein the bidentate phosphite ligand is selected from a member of the group represented by Structure II, wherein
R 1 is isopropyl or cyclopentyl;
R 5 is methyl or isopropyl; and
R 6 , R 7 , and R 8 are H.
8. The process according to claim 1 , wherein the bidentate phosphite ligand is represented by Structure I, wherein
R 1 is isopropyl;
R 2 , R 6 , and R 8 are H; and
R 3 , R 4 , R 5 , and R 7 are methyl.
9. The process according to claim 1 , wherein the temperature is maintained within the range of about 100° C. to about 130° C.
10. The process according to claim 1 , wherein the molar ratio of the hydrogen cyanide in the feed to the butadiene in the feed is in the range of about 0.92:1.00 to about 0.98:1.00.
11. The process according to claim 1 , wherein the molar ratio of the zero-valent nickel in the feed to the butadiene in the feed is in the range of about 0.0001:1.00 to about 0.0010:1.00.
12. The process according to claim 1 , wherein the residence time in the reaction zone is sufficient to maintain the 2-methyl-3-butenenitrile concentration at or below about 10 weight percent of the total mass of the product mixture.
13. The process according to claim 1 , wherein said feed comprises 2-methyl-3-butenenitrile.
14. The process according to claim 1 , wherein the catalyst precursor composition further comprises at least one monodentate phosphite ligand.