Hell-Volhard-Zelinsky reaction

What is Hell-Volhard-Zelinsky reaction?

The Hell-Volhard-Zelinsky reaction involves the α-halogenation of carboxylic acids in the presence of catalytic phosphorus. The reaction likely proceeds through the enol form of the intermediate acyl halide.

Hell-Volhard-Zelinsky halogenation
Hell-Volhard-Zelinsky reaction

The discovery of this reaction is attributed to Carl M. von Hell (1849-1926), who first reported it in 1881. Jacob Volhard (1849-1909) and Nikolai D. Zelinsky (1861-1953) later made modifications and improvements to the reaction.


  • Hell, C. (1881), Ueber eine neue Bromirungsmethode organischer Säuren. [On a new bromination method of organic acids.] Ber. Dtsch. Chem. Ges., 14: 891-893. https://doi.org/10.1002/cber.188101401187
  • Volhard, J. (1887), 4) Ueber Darstellung α-bromirter Säuren. [4) On the preparation of α-brominated acids.] Justus Liebigs Ann. Chem., 242: 141-163. https://doi.org/10.1002/jlac.18872420107
  • Zelinsky, N. (1887), Ueber eine bequeme Darstellungsweise von α-Brompropionsäureester. [On a convenient mode of presentation of α-bromopropionic acid ester.] Ber. Dtsch. Chem. Ges., 20: 2026-2026. https://doi.org/10.1002/cber.188702001452