Abstract: The yield of hexanitrostilbene from the reaction of 2,4,6-trinitrotoluene and an alkali metal or alkaline earth metal hypochlorite, in an aqueous organic solvent, is improved by adjusting the pH of the reaction mixture to within the range 9.5 to 11.0 and then maintaining the pH within that range by the addition of an inorganic buffer. The pH is preferably kept above 9.75, especially from 10 to 10.5.In a preferred embodiment, 2,4,6-trinitrotoluene is contacted with aqueous sodium hypochlorite (containing from 4 to 10% (w/v chlorine) in tetrahydrofuran-methanol. After an initial reaction period of between 0.5 to 3 minutes, an inorganic acid, especially sulphuric or hydrochloric acid is added to the reaction mixture to bring its pH within the required range, and then an inorganic buffer, especially sodium carbonate-sodium bicarbonate, is added to maintain the pH within that range. The controlled reaction proceeds for 1 to 2 hours at -5.degree. to 25.degree. C., preferably 10.degree. to 16.degree. C.

Abstract: The yield of hexanitrostilbene from the reaction of 2,4,6-trinitrotoluene and an alkali metal or alkaline earth metal hypochlorite, in an aqueous organic solvent, is improved by adjusting the pH of the reaction mixture to within the range 9.5 to 11.0 and then maintaining the pH within that range by the progressive addition of an alkali metal hydroxide. The pH is preferably kept above 9.75, especially from 10 to 10.5.In a preferred embodiment, 2,4,6-trinitrotoluene is contacted with aqueous sodium hypochlorite (containing from 4 to 10% (w/v) chlorine) in tetrahydrofuran-methanol. After an initial reaction period of between 0.5 to 3 minutes, an inorganic acid, especially sulphuric or hydrochloric acid, is added to the reaction mixture to bring its pH within the required range, and then an alkali metal hydroxide, especially sodium or potassium hydroxide, is added continuously to maintain the pH within that range. The controlled reaction proceeds for 1 to 2 hours at -5.degree. to 25.degree. C., preferably 10.