Abstract: Carboxylic acid mixtures form unsymmetrical ketones in yields approaching statistical using zirconia catalysts promoted with Group IA and IIA elements. Active catalysts exist in their monoclinic or tetragonal but not cubic form. And the level of promoter loading is generally less than ten percent. The advantages of this catalyst over other ketonization catalysts include its high selectivity to ketones, its low formation of dehydrogenated byproducts, and its stability. The catalyst stability permits its regeneration to remove carbon accumulations by air oxidation. This regeneration restores full catalytic activity.