An improvement is proposed for the removal of the precipitates of a phosphine oxide compound as a by-product from a mixture thereof with an olefin compound obtained by the Wittig reaction for the preparation of the olefin compound from a phosphorane compound and a carbonyl compound. Instead of the conventional procedure of filtration to remove the precipitates, the mixture in a hydrocarbon solvent, after replacement of a non-hydrocarbon solvent with a hydrocarbon solvent, if necessary, is admixed with a lower carboxylic acid such as acetic acid so that the precipitates of the phosphine oxide are dissolved forming a viscous fluid which is immiscible with the mixture of the olefin compound and the hydrocarbon solvent. The fluid containing the dissolved phosphine oxide compound can be easily removed by phase separation so that a great increase is obtained in the yield of the desired olefin compound.
本发明提出了一种改进方法,可去除作为副产品的氧化膦化合物沉淀物,该沉淀物来自氧化膦化合物与烯烃化合物的混合物,该烯烃化合物是由
磷烷化合物和羰基化合物通过威蒂希反应制备的。烃类溶剂中的混合物在必要时用烃类溶剂代替非烃类溶剂后,不采用过滤除去沉淀物的常规程序,而是加入低级
羧酸,如
醋酸,使氧化膦的沉淀物溶解,形成一种与烯烃化合物和烃类溶剂混合物不相溶的粘稠液体。含有溶解的氧化膦化合物的液体可以很容易地通过相分离去除,从而大大提高了所需烯烃化合物的产量。