SEPARATING A SOLVENT FROM A NICKEL CATALYST BY DISTILLATION

摘要

A solvent is at least partially separated from a catalyst. The catalyst comprises nickel and a bidentate phosphorus-containing ligand. The method for separation involves distilling a catalyst solution. The ratio of 2-pentenenitrile to 3-pentenenitrile in distillation column bottoms is controlled to reduce the amount of 3-pentenenitrile which is isomerized to form 2-methyl-3-butenenitrile. Isomerization of 3-pentenenitrile to 2-methyl-3-butenenitrile and subsequent isomerization of 2-methyl-3-butenenitrile to 2-methyl-2-butenenitrile, and/or hydrocyanation of 2-methyl-3-butenenitrile to methylglutaronitrile represents a loss in adiponitrile yield in a process for making adiponitrile.

主权项

1. A method for evaporation of solvent from a catalyst solution comprising solvent and a catalyst, wherein said solvent comprises 2-pentenenitrile and 3-pentenenitrile, wherein said catalyst comprises nickel and a bidentate phosphorus-containing ligand, and wherein said method comprises the steps of:
(a) introducing said catalyst solution into a distillation zone; and (b) evaporating solvent in the distillation zone to form a solvent-depleted catalyst solution comprising said catalyst, 2-pentenenitrile and 3-pentenenitrile, while maintaining the ratio of 3-pentenenitrile to 2-pentenenitrile in said solvent-depleted catalyst solution is 14 or less.