done to avoid the hydrolysis of the thionocarbonates to carbonates which occurs in strongly basic solutions again r is bis 2 fluro 2 2 dinitroethyl thionocarbonate can be prepared from 2 fluoro 2 2 dinitroethanol and thiophosgene using the method disclosed in u s pat no 4 172 088 entitled 34 bis 2 fluoro 2 2 dinitroethyl thionocarbonate and a method of preparation 34 which issued to isaac a angres et al on oct 23 1979 herein incorporated by reference the remaining thionocarbonates can be synthesized from thiophosgene and the appropriate alcohol using the method disclosed in u s pat no 4 323 518 entitled 34 polynitroethylthionocarbonates and method of preparation 34 which issued to willian h gilligan on apr 6 1982 herein incorporated by reference note that the alcohol may be chosen so that either r r 39 or r u2260 r 39 the thionocarbonate alcohol and perchloromethyl mercaptan are dissolved in a suitable solvent such as dichloromethane 1 2 dichloroethane or 1 1 2 trichloroethane the reaction occurs as a strong hydroxyl ion source preferably an alkali metal hydroxide and more preferably naoh or koh is slowly added so that the ph of the reaction mixture does not exceed 8 the reaction temperature is preferably kept at from about 0 u00b0 c to about 5 u00b0 c by external cooling agitation e g stirring and controlled addition of the hydroxyl ion source examples 1 through 5 further illustrate this procedure a phase transfer catalyst e g tetrabutyl ammonium chloride is preferably used to speed up the reactions forming the disulfides phase transfer catalysts such as benzyltriethylammonium chloride tetrabutylammonium chloride didodecyldimethylammonium bromide or cetyltrimethylammonium chloride may be used the phase transfer catalyst is not consumed by the reaction therefore only a small amount a few mole percent of the.