Factors Affecting the Selectivity of Air Oxidation Of 2-Ethyhexanal, an α-Branched Aliphatic Aldehyde

Various solvents and metal catalysts were tested in air oxidation of 2-ethylhexanal to elucidate the effects of different variables on the reaction path of the substrate. The primary goal was to determine the optimal conditions for maximising the yield of carboxylic acid and minimising the formation of other products. Solvents and catalysts both had a significant impact on the product distribution. The best selectivity of 2-ethylhexanal to 2-ethylhexanoic acid, 84%, was obtained with octanoic acid as solvent and manganese(II) acetate as catalyst. Addition of an aromatic aldehyde, benzaldehyde, or p -methoxybenzaldehyde retarded the oxidation rate of both 2-ethylhexanal and aromatic aldehyde dramatically.