This invention concerns a process of preparing alcohols and aldehydes which comprises the steps of contacting a mixture of terminal and/or internal olefins and synthesis gas with a catalyst system comprising a ruthenium-containing compound dispersed in a low melting quaternary phosphonium or ammonium base or salt and heating said resultant reaction mixture under a pressure of 100 psi or greater at a temperature of at least 50.degree. C. for a sufficient time to produce said alcohols and aldehydes.