An innovative light assisted production of acetic acid from CO2 and methanol: a first photocatalytic approach using a reusable cobalt(ii) molecular hybrid at atmospheric pressure

Abstract

Acetic acid is an important commodity chemical which is produced either by fermentation processes, or more commonly, from chemical routes such as methanol carbonylation with CO and H2, acetaldehyde oxidation, or hydrocarbon oxidation. More recently, methanol hydrocarboxylation with CO2 and H2 under thermal catalytic conditions has attracted interest. The synthesis of acetic acid from easily available CO2 is of great significance yet rarely reported. The present paper describes the first photocatalytic approach for the synthesis of acetic acid from methanol and CO2 under ambient reaction conditions without using molecular hydrogen. The maximum conversion of methanol achieved is 60% with selectivity towards acetic acid of 81% using octa-sulfur bound cobalt phthalocyanine (CoPc/S8) photocatalyst without additional sacrificial electron donor. Product analysis and controlled experiments suggest the formation of carbene as a reactive intermediate. The developed methodology represents a potentially exciting approach for synthesizing acetic acid utilizing CO2 in a sustainable manner.