| 摘要 |
The invention relates to a process for purifying crude cyanohydrins having 3 to 6 C atoms, in particular crude acetone cyanohydrin, by distilling off the unconverted reactants hydrogen cyanide and carbonyl compound. The purification system is very simple, and the unconverted reactants can be fed directly to the cyanohydrin synthesis, if the vacuum is generated by a liquid-jet pump which passes the vapours formed during the distillation or desorption to the propulsion jet of the pump, the liquid-jet pump is operated with crude cyanohydrin containing basic catalyst, and the vapours absorbed in the crude cyanohydrin are allowed fully to react to form the cyanohydrin in a cooled reaction circulation, into which the liquid-jet pump is tied. |
