| 摘要 |
A process for purifying an unsaturated nitrile containing hydrogen cyanide in the form of a cyanhydrin which normally tends to decompose during the distillation of the unsaturated nitrile and contaminate the distilled product with hydrogen cyanide comprises adding to the unsaturated nitrile 0.001 to 0.1 pound of oxalic acid per 100 pounds of unsaturated nitrile, and distilling the nitrile in the presence of the oxalic acid. A preferred procedure for the purification of acrylonitrile comprises feeding to a fractional distillation column, near the bottom of said column, a liquid stream of acrylonitrile containing hydrogen cyanide in the form of a cyanhydrin and from 0.001 to 0.1 pound of oxalic acid per 100 pounds of acrylonitrile, vapourising a portion of the liquid from the bottom of the column and condensing the overhead vapours, retaining at least a portion of the condensate of the column and withdrawing near the top of the column a side stream of purified acrylonitrile. |
