Upgrading Ethanol Into Butanol and Higher Alcohols via PN ³ P Iridium Complexes

The production of biofuels from renewable feedstocks to supply energy and alternative fuels has attracted significant attention. In particular, ethanol generated from renewable biomass is recognized as one of the greenest alternatives to gasoline. Herein we accomplished the upgrading of ethanol into butanol, as well as higher branched and linear chain alcohols up to C 10 ─OH, in a single reactor under neat conditions catalyzed by an air‐ and moisture‐stable PN 3 P pincer iridium catalyst. The addition of potassium tert ‐butoxide (KO t Bu, 5.0 mol%) as a base, resulted in the highest turnover number (TON) up to 580, yielding 39% n ‐butanol with up to 95% selectivity. Under similar reaction conditions with a prolonged reaction time of 48 h, we achieved up to 60% ethanol conversion, resulting in a 37% yield of a mixture of linear and branched chain alcohols (C 4+ OH) along with 23% n ‐butanol.