摘要 |
A catalyst (I) containing vanadium, antimony and tin in the oxide state is prepared by making an aqueous slurry of a mixture (II) of compounds of the desired elements followed by drying and calcining the mixture to form active catalyst (I). (II) is a solution comprising SnO2.xH2O (where x >= 0) dispersed in a tetraalkyl ammonium hydroxide of formula (CnH2n+14NOH (1). Also claimed is a process for making an alpha , beta -unsaturated mononitrile, preferably acrylonitrile or methacrylonitrile by the catalytic reaction in the vapour phase of propane or isobutane with oxygen and ammonia in the presence of a catalyst (I) of formula VSbmAaDdOx (2). The mole ratio of paraffin to NH3 is 2.5-16 and the mole ratio of paraffin to O2 is 1-10. n = 1-5; A = Ti and/or Sn where Sn is always present D = Li, Mg, Ca, Sr, Ba, Co, Fe, Cr, Ga, Ni, Zn, Ge, Nb, Zr, Mo, W, Cu, Te, Ta, Se, Bi, Ce, In, As, B, Al and/or Mn. m = 0.5 - 10; a = 0 - 10; d = 0-10; and x is determined by the oxidation state of the cations present. |