Carbonylation in microflow: close encounters of CO and reactive species

Microreactors have brought significant improvements to chemical synthesis and production because of their advantageous characteristics over batch reactors, which include highly efficient mixing, efficient heat and mass transfer ability, precise control of the residence time, large surface area-to-volume ratio and high operational safety. Microreactor technology has been found to be beneficial for gas–liquid biphasic reactions, for which the large interfacial area between the two phases is ensured. Carbonylation reactions with carbon monoxide, by which a wide range of carbonyl compounds can be prepared, deal with a variety of reactive species, such as organo transition metals, radicals, cations and anions. These reactions have long been carried out using a glass batch flask or a stainless-steel made autoclave, however, carbonylation reactions using a flow microreactor are now rapidly increasing in popularity. This review focuses on a new greener wave of carbonylation reactions using a flow microreactor.