Efficient, selective and sustainable catalysis of carbon dioxide
Performing CO2 conversion in a cost-effective and environmentally benign manner would be promising and remains challenging due to its thermodynamic stability and kinetic inertness. Herein, we would like to summarise significant advances in organic synthesis using CO2 with high catalytic efficiency and excellent selectivity towards the target product mainly during the last five years (2012–2016). Achieving an efficient and selective CO2 conversion depends on the development of metal catalysts (especially functional metal complex catalysis) including main-group metal, typical transition metal and lanthanide series metal as well as organocatalysts e.g. N-heterocyclic carbenes, N-heterocyclic olefins, task-specific ionic liquids, superbases and frustrated Lewis pairs that are able to effectively activate CO2 and/or the substrate on the basis of the mechanistic understanding at the molecular level. This review just covers typical catalytic transformation of CO2, for instance, carboxylation, amidation, hydrogenation, and representative green processes like solvent-less, halogen-free that use CO2 as an ideal carbon-neutral source to prepare valuable compounds with improved atom economy and enhanced sustainability of chemical processes through green catalysis. In particular, in situ catalytic CO2 conversion, i.e. the combination of carbon capture and subsequent conversion, a recent breakthrough in the CO2 chemistry field, is also discussed.