High catalytic activity of the PdCl₂(PPh₃)₂–PPh₃–AlCl₃ system containing AlCl3 as promotor has been demonstrated in the reaction of hydroethoxycarbonylation of hexene-1 and octene-1 at low pressure of carbon(II) oxide (≤25 atm). The reaction yields linear and branched products. The optimal conditions of the process have been elaborated. The target products yield is 84.6–93.8%.

The objective of this work was to investigate the possibility of using alkali metal salts of ethylcarbonic acid as a carboxylating reagent in phenol (naphthols) carboxylation and developing a new and simple method for the synthesis of hydroxybenzoic and hydroxynaphthoic acids having broad practical application. It was found that sodium ethyl carbonate and potassium ethyl carbonate can be successfully used as carboxylating agents in carboxylation of phenol and naphthols. For the first time, the effects of the gaseous medium (air, carbon dioxide, argon), pressure, temperature and reaction time on the proceedings of the carboxylation reactions were examined. Simple and convenient procedures for the syntheses of o- and p-hydroxybenzoic, p-aminosalicylic, 1-hydroxy-2-naphthoic, 1-hydroxy-4-naphthoic and 2-hydroxy-3-naphthoic acids were developed. New efficient technologies for preparation of drugs salicylic acid (antiseptic activity), p-aminosalicylic acid (antituberculous activity) and p-hydroxybenzoic acid (bactericide activity) based on carboxylation reactions of phenol and m-aminophenol with sodium and potassium salts of ethyl carbonic acid were worked out.

Carboxylation of -cresol, -cresol, and -cresol with sodium ethyl carbonate (SEC) proceeds regioselectively with the formation of cresotic acids: 2-hydroxy-3-methylbenzoic acid, 2-hydroxy-4-methylbenzoic acid, and 2-hydroxy-5-methylbenzoic acid, respectively. Optimal conditions for conducting the process have been found to be as follows: the reactants ratio of [cresol]: [sodium ethyl carbonate] = (1.5–2): 1, = 180–185°C, = 10 atm, and = 6–7 h. Simple and convenient methods for the synthesis of cresotic acids, which can be used for their industrial manufacturing, have been developed.