ALKYLATION OF CARBOXYLIC-ACIDS BY SOLID-LIQUID PHASE-TRANSFER CATALYSIS FOR DETERMINATION BY GAS-CHROMATOGRAPHY

A solid-liquid phase-transfer catalysed process has been investigated for the alkylation of carboxylic acids. With tetrabutylammonium as counter ion, the bicarbonate ion was solvated in methylene chloride. In this solution carboxylic acids could be quantitatively alkylated in the presence of alkyl iodide. Benzoic acid and acetylsalicylic acid were used as substrates. The reaction could be governed both by the type of alkyl iodide (number of carbon atoms) and by its concentration. The method was found to be especially suitable for the alkylation of compounds sensitive to hydrolysis. Acetylsalicylic acid was thus quantitatively methylated (ρ99%) within 7 min without any sign of decomposition. © 1979.