SEMI-INDUSTRIAL TECHNOLOGY FOR SYNTHESIS OF 2-(1,3-DITHIOLAN-2-YLIDENE) MALONONITRILE

Abstract

This article analyzes the developments of the scientific team of the Chemical and Pharmaceutical Faculty of Chuvash State University I.N. Ulyanov in the field of synthesis of 1,3-dithioheterocycles and based on them a method of synthesis of 2-(1,3-dithiolane-2-ylidene) malononitrile suitable for scaling was developed. The basis was chosen for the well-known three-component synthesis method, which has several disadvantages: the use of toxic and inaccessible reagents, multi-stage. During laboratory testing, this method of synthesis was improved. The developed method for producing 2-(1,3-dithiolane-2-ylidene)malononitrile consists of reacting malononitrile with carbon disulfide in the presence of potassium carbonate, adding dichloroethane to the resulting mixture, and boiling the mixture for 10-15 min. The final compound is isolated by diluting the reaction mass with water. Based on the developed method, a technological scheme for the synthesis of 2- (1,3-dithiolane-2-ylidene)malononitrile was compiled. The selected production method consists of four technological operations: mixing the starting components in the reactor, heating and boiling the reaction mixture, diluting the reaction mass with water and crystallizing the product, filtering 2-(1,3-dithiolane-2-ylidene)malononitrile. The first three stages can be carried out in one technological equipment - a reactor equipped with a stirrer and a jacket. For filtering it is necessary to use a nutsche filter. Based on the developed methodology, a technological scheme has been created, its description has been compiled. The design process capacity is 5 kg/h of 2-(1,3-dithiolane-2-ylidene)malononitrile. The necessary equipment is calculated. A standard mixing reactor with a volume of 0.1 m3 and a nutsche filter NFP-0.25-630 PP were selected. To mix the reaction mass, the reactor should be equipped with an anchor type mixer. The developed technology compares favorably with the use of simple and cheap raw materials common in the chemical industry, the short synthesis time and the use of standard technological equipment.