Abstract <p>A method for producing tetraalkylammonium bromide with one long aliphatic radical in a polar organic solvent medium is described. Isopropyl alcohol is recommended as the solvent for the alkylation reaction of triethylamine with octadecyl bromide, proceeding via a bimolecular nucleophilic substitution mechanism. The influence of the synthesis temperature of triethyloctadecylammonium bromide in isopropyl alcohol on the yield of the target reaction product was studied.</p>