Mixed metal oxide ammoxidation catalysts
View Patent ↗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 comprising a complex of metal oxides comprising bismuth, molybdenum, iron, cerium and other promoter elements, wherein the X-ray diffraction pattern of the catalytic composition has X-ray diffraction peaks at 2θ angle 28±0.3 degrees and 2θ angle 26.5±0.3 degrees, and wherein the ratio of the intensity of the most intense x-ray diffraction peak within 2θ angle 28±0.3 degrees to the intensity of most intense x-ray diffraction peak within 2θ angle 26.5±0.3 degrees is defined as X/Y, and wherein X/Y is greater than or equal to 0.7.
1. A catalytic composition comprising a complex of metal oxides wherein the relative ratios of the elements in said catalyst are represented by the following formula:
Mo 12 Bi a Fe b A c D d E e F f G g Ce h O x
wherein
A is at least one element selected from the group consisting of sodium, potassium, rubidium and cesium; and
D is at least one element selected from the group consisting of nickel, cobalt, manganese, zinc, magnesium, 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 a rare earth element, 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 and n are, respectively, the atomic ratios of bismuth (Bi), iron (Fe), A, D, E, F, cerium (Ce) and oxygen (O), relative to 12 atoms of molybdenum (Mo), wherein
a is from 0.05 to 7,
b is from 0.1 to 7,
c is from 0.01 to 5,
d is from 0.1 to 12,
e is from 0 to 5,
f is from 0 to 5,
g is from 0 to 0.2,
h is from 0.01 to 5, and
n is the number of oxygen atoms required to satisfy the valence requirements of the other component elements present;
wherein 0.15≦(a+h)/d≦1 and 0.8≦h/b≦5, and
wherein the X-ray diffraction pattern of the above identified catalytic composition has X-ray diffraction peaks at 2θ angle 28±0.3 degrees and 2θ angle 26.5±0.3 degrees, and wherein the ratio of the intensity of the most intense x-ray diffraction peak within 2θ angle 28±0.3 degrees to the intensity of most intense x-ray diffraction peak within 2θ angle 26.5±0.3 degrees is defined as X/Y, and wherein X/Y is greater than or equal to 0.7.
2. The catalytic composition of claim 1 , wherein 0.2≦(a+h)/d≦0.6.
3. The catalytic composition of claim 1 , wherein 0.3≦(a+h)/d≦0.5.
4. The catalytic composition of claim 1 , wherein 1≦h/b≦3.
5. The catalytic composition of claim 1 , wherein 1.5≦h/b≦2.
6. The catalytic composition of claim 1 , wherein X/Y is greater than or equal to 0.8.
7. The catalytic composition of claim 1 , wherein X/Y is greater than or equal to 0.90.
8. The catalytic composition of claim 1 , wherein the composition comprises a support selected from the group consisting of silica, alumina, zirconium, titania, or mixtures thereof.
9. The catalytic composition of claim 8 , wherein the support comprises between 30 and 70 weight percent of the catalyst.
10. The catalytic composition of claim 8 , wherein the support comprises silica having an average colloidal particle size in between about 8 nm and about 100 nm.