Synthesis of acrylonitrile from propylene and nitric oxide mixtures on PbO₂-ZrO₂ aerogel catalysts

Abstract

A series of four PbO₂-ZrO₂ aerogel catalysts, differing by their atomic Pb/Zr ratios, were tested at 420 °C in the nitroxidation of propylene 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, TiO₂, Al₂O₃ and SiO₂ also gave interesting results though not so good as ZrO₂. A redox mechanism fits best the kinetic results which involves again a dissociative chemisorption of NO into a N and an oxygen monoatomic adspecies. N₂O and O₂ give only carbon dioxide through a total degradation reaction under the same experimental conditions.