The mechanism of formation of acid chloride is similar to the reaction of alcohols with thionyl chloride. :0-H CI :δ-HC O-HCI R-C=O、 036二R0s上的 CI +HCI OH可 R-C-0-S-CI R-C-0-S-CI a chlorosulfite anhydride The lone pair of the acid carbonyl oxygen attacks the electrophilic sulfur(sulfur analogue of an acid chloride),and chloride is expelled from the tetrahedral intermediate. Deprotonation yields a chlorosulfite anhydride. Ch20 Carboxylic Acids (landscape) Page 23Ch20 Carboxylic Acids (landscape) Page 23 The mechanism of formation of acid chloride is similar to the reaction of alcohols with thionyl chloride. The lone pair of the acid carbonyl oxygen attacks the electrophilic sulfur (sulfur analogue of an acid chloride), and chloride is expelled from the tetrahedral intermediate. Deprotonation yields a chlorosulfite anhydride