Kolbe-Schmitt Reaction-百灵威

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.

Mechanism

Synthesis of Alkyl Bromides

Synthesis of Alkyl Chlorides

Dakin-West Reaction

Related Compounds

Base

Acid Work-up

Carbon Dioxide (CAS 124-38-9)

Kolbe-Schmitt Reaction

Lab Tips

Mechanism

Original Paper

Top Citations

Related Reactions

Related Compounds