An investigation of heterogeneous base catalysed acetone conversion

A series of materials have been compared for their activity in the base catalysed condensation of acetone. Activities have been compared after extended times on stream (18 h) and under a H2 containing atmosphere at elevated pressure which is designed to mimic conditions applicable for the single stage transformation of acetone to MIBK. In general, catalysts without a strong hydrogenation function have been screened and so mesityl oxide is the dominant reaction product. However, 1%Pd5%MgO/SiO2 does exhibit high selectivity towards MIBK, demonstrating that single-stage conversion is possible under the conditions investigated. Catalytic activity is found to be a strong function of the material tested. However, when the influence of surface area is taken into account, a spectrum of area normalised conversion rates is evident. These rates were found to vary in the order 36.5% KNO3/Al2O3 > Li/MgO > 36.5% KNO3/ZrO2 > 36.5% KNO3/Zr(OH)4 > MgO derived from Mg(OH)2.MgCO3 > 14% KNO3/Al2O3 > MgO derived from Mg(OH)2 > 14% KNO3/Zr(OH)4 > ZrO2 > 14% KNO3/ZrO2 > Y-Zr(OH)4. When comparing materials produced from different precursors, differences in catalytic behaviour are apparent implying structure-sensitivity and/or the influence of different impurity contents. The role of dopant, additional phase level and precursor phase has also been examined demonstrating that all these parameters are important