Acid Chlorides

| Home | | Organic Chemistry |

Chapter: Organic Chemistry : Functional Group Synthesis

The traditional methods utilize sulfur or phosphorous halides to convert the acid to the acid chloride.


ACID CHLORIDES

Traditional textbook preparations of acid chlorides from carboxylic acids include


The traditional methods utilize sulfur or phosphorous halides to convert the acid to the acid chloride. Of these methods, thionyl chloride [often with a catalytic amount of dimethyl formamide (DMF)] is the most useful since the by-products of the reaction are gases (SO2, HCl) which can be easily purged from the reaction mixture with a stream of nitrogen. The acid chloride product can then be purified on a small scale by bulb-to-bulb distillation or crystallization. Because an excess of thionyl chloride is usually used, there must be a purification step to remove the excess reagent.

Another superior reagent for the preparation of acid chlorides is oxallyl chlo-ride in methylene chloride. Addition of a carboxylic acid leads to the smooth evolution of gas (CO2, CO, HCl) which can be used as a crude monitor of the reaction progress. The acid chloride is very easily purified since oxallyl chloride boils at 62 C and is easily evaporated from the product. In many instances, the crude product is sufficiently pure to be used directly.


Contact Us, Privacy Policy, Terms and Compliant, DMCA Policy and Compliant

TH 2019 - 2023 pharmacy180.com; Developed by Therithal info.