Carboxylation of phenol and its derivatives with sodium ethyl carbonate

Abstract

A comparison activity of phenol and its derivatives in carboxylation reaction with sodium ethyl carbonate was carried out (the ratio between substrate and sodium ethyl carbonate was 2:1, T=185°С, Pco2=10 atm, τ=7 h). p-Cresol, p-chlorophenol, phenol, m-cresol, p-fluorophenol, p-bromophenol, and m-chlorophenol showed the highest activity in this reaction. o-Cresol and o-chlorophenol showed moderate activity but 2,4-dichlorophenol did not enter into the reaction. The optimum conditions for the carboxylation reaction of phenol with sodium ethyl carbonate under microwave irradiation was determined (microwave irradiation power 450 W, duration 9 min; the ratio of the initial reagents, phenol, and sodium ethylcarbonate was 1.5:1). A comparison activity of phenol and its methyl- and halogen substituted derivatives in the carboxylation reaction with sodium ethyl carbonate under microwave irradiation was conducted. The reaction proceeded in accordance with the rule of electrophilic substitution reaction of aromatic compounds and, in all cases, went selectively into the o-position to form corresponding phenol carbonic acid derivatives with yields ranging from 6.8%–39.5%.

Keywords

• carboxylation
• hydroxybenzoic acids
• phenols
• sodium ethyl carbonate