Abstract: Malonic acid dinitrile is prepared by reacting acetonitrile and cyanogen chloride in the gaseous phase at temperatures from 740.degree. to 780.degree. C. Temperatures from 750.degree. to 760.degree. C. with molar ratios of 1:1 to 1:5 of cyanogen chloride to acetonitrile are preferred. The crude mixture containing malonic acid dinitrile may be purified by conversion of the principal impurities to easily separable compounds by a Diels-Alder or selective hydrogenation reaction.

Abstract: The process for the production of malonic acid dinitrile which includes quickly preheating acetonitrile to a temperature between 110.degree. and 700.degree.C. Cyanogen chloride and the preheated acetonitrile, both in the gaseous state, are reacted at a temperature between 700.degree. and 1200.degree.C. Malonic acid dinitrile, in the gaseous state, results. The reaction product mixture of gaseous malonic acid dinitrile, gaseous cyanogen chloride, gaseous acetonitrile and HCl, a reaction byproduct, is chilled with liquid reaction product mixture to a temperature between 40.degree.C. and the boiling point of the reaction product mixture. A liquid reaction product results. Simultaneously with the chilling step, the exhaust gas resulting from the chilling of the reaction product mixture is distilled or refined to separate the cyanogen chloride and acetonitrile from the HCl component in the exhaust gas. The malonic acid dinitrile is isolated from the liquid reaction product mixture and purified.