HYDROCYANATION PROCESS WITH REDUCED YIELD LOSSES

摘要

The invention provides a hydrocyanation process for the production of adiponitrile and other dinitriles having six carbon atoms, the process comprising: a) forming a reaction mixture in the presence of at least one Lewis acid, said reaction mixture comprising ethylenically unsaturated nitriles having five carbon atoms, hydrogen cyanide, and a catalyst precursor composition, by continuously feeding ethylenically unsaturated nitriles, 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 nitriles, 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 $Q=\frac{X}{\begin{array}{c}[\left(\mathrm{moles}3\mathrm{PN}+4\mathrm{PN}\mathrm{in}\mathrm{the}\mathrm{feed}\right)/\\ \left(\mathrm{moles}\mathrm{all}\mathrm{unsaturated}\mathrm{nitriles}\mathrm{in}\mathrm{the}\mathrm{feed}\right)]-Z\end{array}}$ is in the range from about 0.2 to about 10, wherein 3PN is 3-pentenenitriles and 4PN is 4-pentenenitrile; and 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 multidentate phosphorus-containing ligand; wherein the multidentate phosphorus-containing ligand is selected from the group consisting of a phosphite, a phosphonite, a phosphinite, a phosphine, and a mixed phosphorus-containing ligand or a combination of such members; and wherein the multidentate phosphorus-containing ligand gives acceptable results according to at least one protocol of the 2-Pentenenitrile Hydrocyanation Test Method.