Question

what is hell vord reaction​

Answer 1

Answer:

Mechanism of the Hell-Volhard-Zelinsky Reaction

Phosphorus reacts with bromine to give phosphorus tribromide, and in the first step this converts the carboxylic acid into an acyl bromide. An acyl bromide can readily exist in the enol form, and this tautomer is rapidly brominated at the α-carbon.

Answer 2

Answer:

The Hell Volhard Zelinsky reaction demonstrates a method for alpha addition with a carboxylic acid. The gist of the method is to convert the carboxylic acid into a derivative that does undergo tautomerization and then to carry out alpha addition upon that form.

In the Hell Volhard Zelinsky reaction PBr3 is used to replace the carboxylic OH with a bromide, resulting in a carboxylic acid bromide