TRANSFORMATION OF ACETONE OVER A 0.4PTHMF(60) CATALYST - REACTION SCHEME

The transformation of acetone was carried out over a 0.4 wt% PtHMFI ca talyst (Si/Al = 60) under the following conditions: flow reactor, 160 degrees C, pressures of acetone and hydrogen equal to 0.75 and 0.25 ba r, respectively. Methylisobutylketone, propane and traces of mesitylox ide are observed as primary products while the other main products: 2- methylpentane and diisobutylketone result from secondary transformatio n of methylisobutylketone. The reactivity of the reaction products and of probable intermediates: diacetone alcohol, isopropanol and propene was compared to that of acetone, which allows us to establish the com plete scheme of acetone transformation. Acetone is competitively trans formed through bifunctional catalysis into methylisobutylketone and in to propane. The limiting step of methylisobutylketone formation is ace tone aldolisation over the acid sites of the catalyst while that of pr opane formation is acetone hydrogenation over platinum sites. Methylis obutylketone undergoes the same competitive bifunctional transformatio ns leading to diisobutylketone (limiting step: acid coaldolisation of acetone and of methylisobutylketone) and to 2-methylpentane (limiting step: hydrogenation of methylisobutylketone). (C) 1997 Elsevier Scienc e B.V.