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 acids can be brominated in the alpha position with a mixture of Br2 and PBr3 in a reaction called the Hell-Volhard-Zelinskii reaction. The classical method to convert carboxylic acids into α-haloacyl halides using phosphorus(III) halide is known as the Hell-Volhard-Zelinsky.

Author: Kajira Kijinn
Country: Guadeloupe
Language: English (Spanish)
Genre: Literature
Published (Last): 9 October 2015
Pages: 296
PDF File Size: 2.86 Mb
ePub File Size: 16.36 Mb
ISBN: 258-4-57525-176-6
Downloads: 40396
Price: Free* [*Free Regsitration Required]
Uploader: Juzshura

For help asking a good homework question, see: This was a question where AJ needed to make some effort in offering a solution.

However, I hope it will serve others as well. If an aqueous solution is desirable, a full molar equivalent of PBr 3 must be used as the catalytic chain is disrupted. Reason behind conversion of acid to acid bromide in Hell-Volhard-Zelinsky reaction [closed] Ask Question.

This page was last edited on 29 Augustat The mechanism for the exchange between an alkanoyl bromide and a carboxylic acid is below. Retrieved from hell-volhsrd-zelinsky https: By using this site, you agree to the Terms of Use and Privacy Policy.


Hell-Volhard-Zelinsky reaction

Unlike reactoin halogenation reactions, this reaction takes place in the absence of a halogen carrier. The reaction is initiated by addition of a catalytic amount of PBr 3after which one molar equivalent of Br 2 is added. In other projects Wikimedia Commons. PBr 3 replaces the carboxylic OH with a bromide, resulting in a carboxylic acid bromide.

Hell-Volhard-Zelinsky Reaction – ChemistryScore

The reaction is named after three chemists, the German chemists Carl Magnus von Hell — and Jacob Volhard — hell-volhadd-zelinsky the Russian chemist Nikolay Zelinsky — Views Read Edit View history. The users who voted to close gave this specific reason: Sometimes, phosphorus tribromide is not enough to form the acyl halide but, since there is also bromine in the media, phosphorus pentabromide is formed which can form acyl halides even of solid acids.

The phosphorus halides form the acyl halides readily because phosphorus has a huge affinity for oxygen. This question appears to be off-topic. Substitution reactions Halogenation reactions Name reactions.


Acyl halides lack the carboxylic acid hydrogen. Home Questions Tags Users Unanswered. From Wikipedia, the helk-volhard-zelinsky encyclopedia.

Hell Volhard Zelinsky Reaction | [email protected]

How do you think the alpha-bromine is incorporated into the acyl bromide? How do I ask homework questions on Chemistry Stack Exchange?

Raoul Kessels 3, 2 By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. In practice a molar equivalent of PBr 3 is often used anyway to overcome the slow reaction kinetics.

Google is your friend!

Chemistry Stack Exchange works best with JavaScript enabled.

Subscribe US Now