A closed cycle for esterifying aromatic hydrocarbons with CO 2 and alcohol

The ability to functionalize hydrocarbons with CO could create opportunities for high-volume CO utilization. However, current methods to form carbon-carbon bonds between hydrocarbons and CO require stoichiometric consumption of very resource-intensive reagents to overcome the low reactivity of these substrates. Here, we report a simple semi-continuous cycle that converts aromatic hydrocarbons, CO and alcohol into aromatic esters without consumption of stoichiometric reagents. Our strategy centres on the use of solid bases composed of an alkali carbonate (M CO , where M = K or Cs ) dispersed over a mesoporous support. Nanoscale confinement disrupts the crystallinity of M CO and engenders strong base reactivity at intermediate temperatures. The overall cycle involves two distinct steps: (1) CO -promoted C-H carboxylation, in which the hydrocarbon substrate is deprotonated by the supported M CO and reacts with CO to form a supported carboxylate (RCO M); and (2) methylation, in which RCO M reacts with methanol and CO to form an isolable methyl ester with concomitant regeneration of M CO .