The Kolbe-Schmidt reaction or Kolbe reaction is a carboxylation chemical reaction that proceeds by heating sodium phenolate (the sodium salt of phenol) with carbon dioxide under pressure (100 atm, 125∘C ), then treating the product with sulphuric acid. The final product is salicylic acid, which is the precursor of aspirin (analgesic)
The Kolbe-Schmidt reaction proceeds via the nucleophile addition of a phenolate to carbon dioxide to give the salicylate. In this reaction, CO2 act as an electrophile. The final step is reaction of salicylate with acid to form desired salicylic acid.