Printer Friendly
Dictionary, Encyclopedia and Thesaurus - The Free Dictionary
3,899,053,785 visitors served.
forum Join the Word of the Day Mailing List For webmasters
?
Dictionary/
thesaurus
Medical
dictionary
Legal
dictionary
Financial
dictionary
Acronyms
 
Idioms
Encyclopedia
Wikipedia
encyclopedia
?

Ullmann Reaction

   Also found in: Wikipedia 0.01 sec.
Ullmann reaction [′əl·mən rē‚ak·shən]
(organic chemistry)
A variation of the Fittig synthesis, using copper powder instead of sodium.

Ullmann Reaction 

a method of obtaining binuclear and polynuclear aromatic compounds by heating aryl halides (ArX, where X = CI, Br, I) at 100°-360°C with powdered copper. One example of the Ullmann reaction is the synthesis of diphenyl from iodobenzene:

2C6H5I + Cu → C6H5 - C6H5 + Cul2

Iodine derivatives enter into the Ullmann reaction more readily. An increased yield is made possible by the activation of copper, for example, with iodine in acetone, and by the application of a solvent—dimethylformamide. It is assumed that the Ullmann reaction proceeds according to a free-radical mechanism. Discovered by F. Ullmann in 1896, the reaction is used, for example, in the manufacture of vat dyes.



Want to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit the webmaster's page for free fun content.
?Page tools
Printer friendly
Cite / link
Feedback
Mentioned in?   Encyclopedia browser?   Full browser?
No references found
 
 
 
Encyclopedia
?

Terms of Use | Privacy policy | Feedback | Advertise with Us | Copyright © 2012 Farlex, Inc.
Disclaimer
All content on this website, including dictionary, thesaurus, literature, geography, and other reference data is for informational purposes only. This information should not be considered complete, up to date, and is not intended to be used in place of a visit, consultation, or advice of a legal, medical, or any other professional.