Synthesis of carboxylic acids via the hydrocarboxylation of alcohols with CO₂ and H₂

Production of higher carboxylic acids from CO₂ and H₂ is a novel and very attractive topic. Herein we present a protocol of synthesizing C₃₊ carboxylic acids via the reaction of alcohols with CO₂ and H₂. A catalytic system consisting of iridium(III) acetate and LiI could effectively accelerate this reaction. The reaction could occur at above 120 °C and the best result was obtained at 170 °C. The catalytic system could be applied to various alcohols (primary, secondary, and tertiary alcohols and polyols). The reaction mechanism was proposed based on systematic control experiments.