Hell Volhard – Zelinsky reaction: When a carboxylic acid that contains α-hydrogen is treated with Cl2 or Br2 in the presence of red phosphorus, the α-hydrogen atom are replaced by chlorine or bromine atoms. This reaction is known as the Hell Volhard – Zelinsky reaction.
The reaction is named after three chemists, the German chemists Carl Magnus von Hell (1849–1926), Jacob Volhard (1834–1910) and the Russian chemist Nikolay Zelinsky (1861–1953).
The Hell-Volhard-Zelinsky reaction is an organic reaction used to convert a carboxylic acid with an α-hydrogen and a halogen, to an α-halo carboxylic acid, using a phosphorous catalyst and water.
