An efficient Cu-CeO₂ citrate catalyst for higher aliphatic ketone synthesis via alkali-free alkylation of acetone with butanol

Abstract

A remarkable effect of Cu-CeO2 citrate catalyst was examined for the alkylation of acetone with butanol for making jet-fuel range precursors under elevated reaction conditions, in which 2-heptanone and 6-undecanone were produced as major products with 3-heptene-2-one, 2-heptanol, and butyl butyrate in minor quantities. The catalytic performance was measured over 10 wt% Cu-CeO2 catalysts prepared by calcination at 400-800 degrees C with an interval of 100 degrees C followed by identical H-2 activation. Interestingly, the alkylation activity exhibited a volcano-shaped trend with respect to the calcination temperature as copper particle size and basicity played a vital role. The activity results revealed the optimum calcination temperature of 600 degrees C (namely, Cu-CeO2-600). When the catalysts prepared by two classical methods such as impregnation and co-precipitation were tested under an identical condition, the citrate method turned out to yield a highly stable nanocatalyst with the following features: the copper particles protected by CeO2, a high amount of surface copper species, and the basicity. These are responsible for sturdiness of Cu-CeO2-600 citrate catalyst in the production of higher aliphatic ketone.