Catalytic Ketonisation over Oxide Catalysts. Part VII. Ketonisation and Cross-Ketonisation of Aliphatic Esters over CeO2 and ZrO2 Supported on Alumina

Catalysts of general formula xwt% MO2/Al2O3, where x = 10, 20 or 30 and M = Ce or Zr have been studied in the ketonisation and cross-ketonisation of aliphatic esters under flow conditions between 548-723 K. Ketonisation of ethyl pentanoate, heptanoate and nonanoate has led to nonan-5-one, tridecan-7-one and heptadecan-9-one, respectively. The conversion of esters increased with temperature and at 698 K a quantitative conversion was observed, irrespective of the type of ester used. A maximum yield of ketone (46% for nonan-5-one, 60% for tridecan-7-one and 50% for heptadecan-9-one) was observed at 673 K. As a result of the cross-ketonisation of a mixture of ethyl pentanoate and ethyl nonanoate (3:1 molar ratio), three ketones were formed: nonan-5- one, tridecan-5-one and heptadecan-9-one. At 698 K, maximum yields of ketones were noted (37, 46 and 8%, respectively) together with a 90% conversion of esters. The catalysts were characterized by XRD, TPR and surface area measurements.