Reaction of Alcohols with Thionyl Chloride

Reaction of alcohols with thionyl chloride followed by hydrochloric acid results in the replacement of the hydroxyl group of the alcohol with a chloride substituent, forming an alkyl chloride product. This mechanism does not, like dehydrohalogenation, pass through a carbocation intermediate. Therefore, rearrangement cannot occur in reaction with thionyl chloride. Note that thionyl chloride can also convert a carboxylic acid into an acid chloride.