Production of alkylsalicyl acids by carboxylation of alkylphenols

An important stage in the industrial process for obtaining salicylate additives for oils and fuels is the synthesis of alkylsalicylic acids from alkylphenols, which is based on the addition reaction of carbon dioxide CO2 to organic substances with the formation of a carboxyl group - COOH (Kolbe-Schmitt reac-tion). This work is devoted to optimizing this stage of the process in terms of increasing the rate of the main reaction while achieving the maximum equilibrium yield of alkylsalicylic acid. As a result of the ex-perimental studies carried out, the process conditions appropriate in this respect for alkyl (C16-C18) phenols were determined. At present, the parameters established in this way have been proposed to produce alkyl salicylate additives at LLC Novokuibyshevsk Plant of Oils and Additives of Rosneft Oil Company, where they form the basis of the current technological regulations.