Sb-containing catalysts by Sb-oxide impregnation

An improved antimony-based oxidation catalyst comprising a used antimony-based oxide complex defined by the formula:

• A.sub.a B.sub.b C.sub.c M.sub.d Sb.sub.e O.sub.x
• wherein
• M is U, Fe, Mn, Ce, Th, Sn, Ti or mixtures thereof;
• A is Mo, W or mixtures thereof;
• B is V, Te, Cr, Cu, Bi or mixtures thereof;
• and
• C is Ni, Co, alkali metal, alkaline earth metal or mixtures thereof;
• and
• wherein
• 0.ltoreq.a.ltoreq.10;
• 0.ltoreq.b.ltoreq.10;
• .ltoreq. c.ltoreq.10;
• 0.1.ltoreq.d.ltoreq.10;
• 5.ltoreq.e.ltoreq.100;
• and
• x is a number sufficient to satisfy the valence requirements of the other elements present.
• impregnated with 0.1 to 25% of an antimony-containing compound impregnant, the percents being based on the atoms of antimony in the impregnant and the atoms of antimony in said oxide complex, said improved antimony-based oxidation catalyst capable of producing acrylonitrile in the ammoxidation of propylene in greater yields than said used oxide complex.

A process for improving the catalytic performance of an antimony-containing oxide complex catalyst defined by the formula:

• A.sub.a B.sub.b C.sub.c M.sub.d Sb.sub.e O.sub.x
• wherein
• M is Fe, Mn, Ce, Th, Sn, Ti or mixtures thereof;
• A is Mo, W or mixtures thereof;
• B is V, Te, Cr, Cu, Bi or mixtures thereof;
• and
• C is Ni, Co, alkali metal, alkaline earth metal or mixtures thereof;
• and
• wherein
• 0.ltoreq.a.ltoreq.10;
• 0.ltoreq.b.ltoreq.10;
• 0.ltoreq.c.ltoreq.10;
• 0.1.ltoreq.d.ltoreq.10;
• 5.ltoreq.e.ltoreq.100;
• and
• x is a number sufficient to satisfy the valence requirements of the other elements present,
• said process comprising adding to said catalyst an antimony-containing compound in an amount such that the amount of antimony added to said catalyst is 0.1 to 25% based on the antimony in said catalyst.