Synthesis of higher carboxylic acids from ethers, CO 2 and H 2

Synthesis of higher carboxylic acids using CO 2 and H 2 is of great importance, because CO 2 is an attractive renewable C1 resource and H 2 is a cheap and clean reductant. Herein we report a route to produce higher carboxylic acids via reaction of ethers with CO 2 and H 2 . We show that the reaction can be efficiently catalyzed by an IrI 4 catalyst with LiI as promoter at 170 °C, 5 MPa of CO 2 and 2 MPa of H 2 . The catalytic system applies to various ether substrates. The mechanistic study indicates that the ethers are converted to olefins, which are further transformed into alkyl iodides. The higher carboxylic acids are produced by carbonylation of alkyl iodides with CO generated in situ via RWGS reaction. This report offers an alternative strategy of higher carboxylic acid synthesis and CO 2 transformation.