A new route for preparing 2,4-dinitrophenylhydrazones by treating aromic aldehydes or alkane ketones and 2,4-dinitrophenylhydrazines with anhydrous calcium chloride as a catalyst.

• 研究了以无水氯化钙为催化剂在中性条件下合成2,4-二硝基苯腙的新方法。