Catalysed synthesis of 4-heptanone from 1-butanol

While investigating the reaction of 1-butanol over base catalysts, such as MgO, we observed the formation of small amounts of 4-heptanone. Further studies revealed that a CeO2/MgO catalyst gave good selectivity to this product. To optimise the reaction and determine the reaction mechanism a series of studies were undertaken in which a range of variables were modified viz. cerium loading, temperature, reagent composition and water addition. The optimum conditions for 4-heptanone yield (25.5%) and selectivity (42.5%) were found to be: 450 degrees C, 1:6 oxygen to butanol reagent mixture and a total gas flow rate of 6.74 ml/min. A reaction mechanism in which butanol is oxidised to butanal and then butanoic acid followed by the coupling of two equivalents of butanoic acid to give the symmetrical ketone 4-heptanone and CO2 is proposed. (C) 1999 Elsevier Science B.V. All rights reserved.