Activity of 20 wt.% MO2/Al2O3 catalysts, where M = Mn, Ce and Zr has been studied in cross-ketonization of ethyl esters of aliphatic and aromatic acids in a flow system. Pentan-3-one and tridecan-7-one were formed in ketonization of pure aliphatic esters, ethyl propanoate and ethyl heptanoate. Benzene was obtained instead of diphenylmethanone as the product of ethyl benzoate transformations. Only two ketones, dialkyl and aralkyl, were obtained from the cross-ketonization of a mixture of aliphatic and aromatic esters. The highest yield of 1-phenyl-1-heptanone (70%) from ethyl heptanoate and ethyl benzoate was reached at 698 K in the presence of MnO2/Al2O3 catalyst. Under similar conditions cross-ketonization of a mixture of ethyl propanoate and ethyl benzoate led to 1-phenyl-1-propanone (60% at 673 K).