| abstract |
The invention provides a hydrocyanation process for the production of adiponitrile and other dinitriles having six carbon atoms, the process comprising:n a) forming a reaction mixture in the presence of at least one Lewis acid, said reaction mixture comprising ethylenically unsaturated nitrites having five carbon atoms, hydrogen cyanide, and a catalyst precursor composition, by continuously feeding ethylenically unsaturated nitrites, hydrogen cyanide, and a catalyst precursor composition; b) controlling X and Z, wherein X is the overall feed molar ratio of 2-pentenenitriles to all unsaturated nitriles and Z is the overall feed molar ratio of hydrogen cyanide to all unsaturated nitrites, by selecting a value for X in the range from about 0.001 to about 0.5, and a value for Z in the range from about 0.5/1 to about 0.99/1, such that the value of quotient Q, wherein nn n n n n Q n = n n X n n n [ n n n ( n n n moles n n n n n n 3 n n PN n n + n n 4 n n PN n n n n n n in n n n n n n the n n n n n n feed n n n ) n n n ( n n moles n n n n n n all n n n n n n unsaturated n n n n n n nitriles n n n n n n in n n n n n n the n n n n n n feed n n ) n n n ] n n - n Z n n n n n n n is in the range from about 0.2 to about 10, wherein 3PN is 3-pentenenitriles and 4PN is 4-pentenenitrile; andn c) withdrawing a reaction product mixture comprising adiponitrile; wherein the ratio of the concentration of 2-pentenenitriles to the concentration of 3-pentenenitriles in the reaction mixture is from about 0.2/1 to about 10/1; wherein the catalyst precursor composition comprises a zero-valent nickel and at least one bidentate phosphite ligand; andn nwherein the bidentate phosphite ligand is selected from a member of the group represented by Formulas I and 11 as described herein. |