Mixed metal oxide catalysts
Catalytic compositions are provided that are effective for providing increased acrylonitrile product without a significant decrease in hydrogen cyanide and/or acetonitrile production and provide an overall increase in production of acrylonitrile, hydrogen cyanide and acetonitrile. The catalytic compositions include a complex of metal oxides and include at least about 15% m-phase plus t-phase by weight and have a weight ratio of m-phase to m-phase plus t-phase of 0.45 or greater.
1. A process for production of acrylonitrile comprising contacting propylene, ammonia and oxygen in a vapor phase in the presence of a metal oxide catalyst, the metal oxide catalyst having a 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;
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;
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
x is a number of oxygen atoms required to satisfy valence requirements of other component elements,
wherein the catalytic composition includes at least about 15% m-phase plus t-phase by weight and has a weight ratio of m-phase to m-phase plus t-phase of 0.45 or greater, where amounts of m-phase and t-phase are determined using x-ray diffraction and a modified Rietveld analysis model,
wherein the catalytic composition is effective for providing an acrylonitrile yield (% AN) of 81 or greater and an acrylonitrile yield (% AN) plus acetonitrile yield (% ACN) plus hydrogen cyanide (% HCN) of 88 or more.
2. The process of claim 1 wherein the modified Rietveld analysis model includes four major phases.
3. The process of claim 1 wherein the catalyst composition includes a support selected from the group consisting of silica, alumina, zirconia, titania, or mixtures thereof.
4. The process of claim 1 wherein the catalytic composition includes at least about 18% m-phase plus t-phase by weight.
5. The process of claim 4 wherein the catalytic composition includes at least about 20% m-phase plus t-phase by weight.
6. The process of claim 5 wherein the catalytic composition includes at least about 22% m-phase plus t-phase by weight.
7. The process of claim 1 wherein the acrylonitrile yield (% AN) is 82 or greater.
8. The process of claim 7 wherein the acrylonitrile yield (% AN) is 83 or greater.