- Kolbe-Schmitt reaction
The Kolbe-Schmitt reaction/Kolbe process (named after
Adolph Wilhelm Hermann Kolbe andRudolf Schmitt ) is acarboxyl ationchemical reaction that proceeds by heating sodium phenolate (thesodium salt ofphenol ) withcarbon dioxide under pressure (100 atm, 125°C), then treating the product withsulfuric acid . The final product is anaromatic hydroxyacid which is also known assalicylic acid (the precursor toaspirin ). [cite journal
title = Ueber Synthese der Salicylsäure
author = Hermann Kolbe
journal =Annalen der Chemie und Pharmacie
year = 1860
volume = 113
issue = 1
pages = 125–127
doi = 10.1002/jlac.18601130120] [cite journal
title = Beitrag zur Kenntniss der Kolbe'schen Salicylsäure Synthese
author = R. Schmitt
journal =Journal für Praktische Chemie
year = 1885
volume = 31
issue = 1
pages = 397–411
doi = 10.1002/prac.18850310130] [cite journal
author = A. S. Lindsey and H. Jeskey
title = The Kolbe-Schmitt Reaction
year = 1957
journal =Chem. Rev.
volume = 57
issue = 4
pages = 583–620
doi = 10.1021/cr50016a001 (Review)]By using the
potassium salt 4-hydroxybenzoic acid is accessible, an important precursor for the versatileparaben class ofbiocides used e.g. in personal care products.Reaction mechanism
The Kolbe-Schmitt reaction proceeds via the nucleophilic addition of a phenolate to carbon dioxide to give the salicylate. The final step is reaction of the salicylate with acid to form the desired salicylic acid.
References
Wikimedia Foundation. 2010.