Preparation and characterization of Ni-CaO catalyst for one step synthesis of MIBK (methyl isobutyl ketone) from acetone

One step synthesis of MIBK (methyl isobutyl ketone) from acetone over co-impregnated Ni-CaO catalyst and Ni effect on the thermal decomposition of CaCO3 into CaO were studied. Bulk calcium acetate, one of catalyst precursors, decomposed into CaCO3 and kacetone at 400-450 degrees C, and CaCO3 into CaO and CO2 at 700 degrees C. But, when nickel acetate for 2 wt% Ni was added into calcium acetate, the decomposition temperature of CaCO3 was decreased to 500 degrees C in H-2/N-2 stream but not in O-2/N-2 stream or air, and in case of 20 wt% Ni, this phenomenon was more drastic. From TPD-MS experiment, we found out that Ni-added CaCo3 did not decompose directly into CaO and CO;? but via the route of CaCO3 + 4H(2) --> CaO + CH4 + 2H(2)O, supposed to have a relatively low activation barrier. CaO can be formed even at 500 degrees C with the aid of Ni and H-2. When 2 wt% Ni-CaO reduced at 500 degrees C for one step synthesis of MIBK was used, 60-80% of acetone overall conversion and 50-60% of MIBK selectivity were obtained.