The Kolbe-Schmitt reaction uses a base, carbon dioxide, and an acid work-up to convert a phenol to an ortho- or para- hydroxy benzoic acid. First the base deprotonates the phenol, forming phenoxide, which attacks carbon dioxide. Tautomerization and an acid work-up yields the final product. A large counterion such as cesium hinders attack of the carbon dioxide at the ortho position, favoring the para-substituted product. Small counterions such as sodium or potassium ion favor the ortho product.

  • Reagents: Base [Alkali or Alkaline Earth Hydroxides (e.g. NaOH, CsOH, Ca(OH)2), K2CO3, KHCO3], Carbon Dioxide (5-100 atm), Acid Work-Up
  • Reactant: Phenol, Substituted Phenol, Naphthol or Electron-Rich Heteroaromatic Compound (e.g. Hydroxypyridine, Carbazole, etc.)
  • Product: Ortho- or Para-Substituted Aromatic Hydroxy Acid
  • Type of Reaction: Electrophilic Aromatic Substitution

Lab Tips

  • Reactants, reagents, and solvents should be thoroughly dried before use as the presence of water decreases the yield of product.
  • Phenols with more than two hydroxyl groups can be carboxylated with carbon dioxide at atmospheric pressure.
Kürti, L., Czakó, B. (2005). Strategic Applications of Named Reactions in Organic Synthesis; Background and Detailed Mechanisms. Burlington, MA: Elsevier Academic Press.


Top Citations

Original Paper

Related Reactions

  • Mitsunobu Reaction
  • Staudinger Reaction
  • Synthesis of Alkyl Bromides
  • Synthesis of Alkyl Chlorides
  • Dakin-West Reaction

Related Compounds

  • Base
  • Acid Work-up
By shuhan yang


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