SYNTHESIS OF ACRYLONITRILE FROM PROPYLENE AND NITRIC-OXIDE MIXTURES ON PBO2-ZRO2 AEROGEL CATALYSTS

A series of four PbO2-ZrO2 aerogel catalysts, differing by their atomi c Pb/Zr ratios, were tested at 420-degrees-C in the nitroxidation of p ropylene into acrylonitrile. All catalysts were active, selective and stable with time on stream. The reactant mixture compositions exerted an influence on the catalytic results; other supports such as MgO, TiO 2, Al2O3 and SiO2 also gave interesting results though not so good as ZrO2. A redox mechanism fits best the kinetic results which involves a gain a dissociative chemisorption of NO into a N and an oxygen monoato mic adspecies. N2O and O2 give only carbon dioxide through a total deg radation reaction under the same experimental conditions.