A process comprising reacting hydrogen and a reaction composition comprising a carboxylic acid and/or derivative thereof in a reactor to produce a reaction composition comprising one or more C.sub.1 compounds selected from one or more of carbon monoxide (CO), carbon dioxide (CO.sub.2) and methane (CH.sub.4), and one or more product hydrocarbons derived from the carboxylic acid and/or derivative thereof, wherein the molar ratio of C.sub.1 compounds produced by the reaction to the carboxylate groups present in the carboxylic acid and/or derivative thereof in the reaction composition is maintained above a value of 0.37:1.