Barbara Knight Warren

Ethanol from H2 and CO via homogeneous ruthenium catalysis

Abstract Ruthenium carbonyl complexes in the presence of an iodide promoter, an acid, and a phosphine oxide provide an unusually selective catalytic system for the direct conversion of CO and H2 to ethanol. Reaction conditions studied range from 30 to 87 MPa and 180 to 250 °C (1 MPa = 9.87 atm). Other products include methanol, methane, acetaldehyde, ethylene glycol, and n-propanol. Much of the ethanol may be derived from initially formed methanol, and the acid component appears to be necessary to facilitate this homologation process. The basic phosphine oxide solvent levels the acidity of the solution, preventing a strong acid from protonating and destroying basic metal complexes involved in the CO hydrogenation process.