Mixed metal oxide ammoxidation catalysts
A catalytic composition useful for the conversion of an olefin selected from the group consisting of propylene, isobutylene or mixtures thereof, to acrylonitrile, methacrylonitrile, and mixtures thereof. The catalytic composition comprises a complex of metal oxides comprising rubidium, bismuth, cerium, molybdenum, iron and other promoters, with a desirable composition.
1. A catalytic composition comprising a complex of metal oxides wherein the relative ratios of the listed elements in said catalyst are represented by the following formula:
Mo m Bi a Fe b A c D d E e F f G g Ce h Ni i Co j Mn k Mg l Rb n O x
wherein
A is at least one element selected from the group consisting of lithium, sodium, potassium, and cesium; and
D is at least one element selected from the group consisting of zinc, calcium, strontium, cadmium and barium;
E is at least one element selected from the group consisting of chromium, tungsten, boron, aluminum, gallium, indium, phosphorus, arsenic, antimony, vanadium and tellurium;
F is at least one element selected from the group consisting of lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium thulium, ytterbium, lutetium, scandium, yttrium, titanium, zirconium, hafnium, niobium, tantalum, aluminum, gallium, indium, thallium, silicon, germanium and lead;
G is at least one element selected from the group consisting of silver, gold, ruthenium, rhodium, palladium, osmium, iridium, platinum and mercury; and
a, b, c, d, e, f, g, h, i, j, k, l, m, n and x are, respectively, the atomic ratios of bismuth (Bi), iron (Fe), A, D, E, F, G, cerium (Ce), nickel (Ni), cobalt (Co), manganese (Mn), magnesium (Mg), rubidium (Rb) and oxygen (O), relative to “m” atoms of molybdenum (Mo),
wherein
a is greater than 0, but less than or equal to 7,
b is 0.1 to 7,
c is greater than 0, but less than or equal to 5,
d is 0.1 to 12,
e is 0 to 5,
f is 0 to 5,
g is 0 to 0.2,
h is 0.01 to 5,
i is 0.1 to 12,
j is 0.1 to 12,
k is 0.1 to 12,
l is 0.1 to 12,
m is 10 to 15,
n is greater than 0, but less than or equal to 5,
x is the number of oxygen atoms required to satisfy the valence requirements of the other component elements present; and
wherein
z=d+i+j+k+l;
0.3≦( a+h )/ z;
1.2≦ h/b≦ 5;
0< a/h< 1.5;
0.2< i /( i+j+k+ 1); and
0<( n+c )/( a+h )≦0.2.
2. The catalyst composition of claim 1 , wherein 0.02<(n+c)/(a+h)≦0.2.
3. The catalyst composition of claim 1 , wherein 0.04<(n+c)/(a+h)≦0.15.
4. The catalyst composition of claim 1 , wherein 0.06≦(n+c)/(a+h)≦0.12.
5. The catalyst composition of claim 1 , wherein 0.45<a/h<1.5.
6. The catalyst composition of claim 1 , wherein 0.8≦a/h≦1.2.