in order to decompose the chlorosulfonic acid 3 kg of ice were initially present in the mixture and an additional 9 5 kg of ice were added during the dropwise addition the solid precipitate formed was recovered by filtration dissolved in dichloromethane 1000 ml the solution dried over na 2 so 4 filtered diluted with hexane and concentrated by distillation until buff colored crystalline needles began to appear the crystalline solid was recovered by filtration washed with hexane and dried as a result of these operations the desired title compound having an m p of 158 u00b0 159 u00b0 c was recovered in a yield of about 84 analysis calc 39 d for c 14 h 8 cl 2 o 4 s c 48 99 h 2 35 cl 20 66 s 9 34 found c 49 0 h 2 59 cl 20 42 s 9 22 confirmation that the chlorosulfonation occurred at the 3 39 ring position was obtained by photolytically chlorinating and then hydrolyzing the product to 2 3 39 4 39 dichlorobenzoyl benzoic acid a known compound having an m p of 185 u00b0 187 u00b0 c the m p of the product obtained was 185 u00b0 186 u00b0 c thus confirming the chlorosulfonation in the 3 39 ring position had the chlorofulfonation occurred in the 2 39 ring position another known compound 2 2 39 4 39 dichlorobenzoyl benzoic acid having an m p of 100 u00b0 101 u00b0 c would have been obtained glass ampoules 12 34 u00d7 1 34 were charged.