Proton transfer in the tetrahedral intermediate converts the hydroxyl group
into –
+OH2 group, which, being a better leaving group, is eliminated as neutral water
molecule The protonated ester so formed finally loses a proton to give the ester 3 Reactions with PCl5, PCl3 and SOCl2
The hydroxyl group of carboxylic acids, behaves like that of alcohols
and is easily replaced by chlorine atom on treating with PCl5, PCl3 or
SOCl2