US 4,812,300 A · Selective perovskite catalysts to oxidize ammonia to nitric oxide

Abstract

The present invention relates to perovskite mixed metal catalysts useful for the selective oxidation of ammonia to nitric oxide. In one aspect, the invention relates to a perovskite mixed metal catalyst of the general formula: ABO.sub.3 wherein: A is selected from alkali, alkaline earth, rare earth, lanthanide activide metals or mixtures thereof; and B is selected from an element or a combination of elements selected from Groups IB, IVB, VB, VIB, VIIB or VIII of the Periodic Table. Preferably, the perovskite phase for each catalyst has an equilibrium oxygen partial pressure at 1000.degree. C. of at least (about) 10.sup.-15 bar. A preferred embodiment is a catalyst wherein A is selected from lanthanum, strontium or mixtures thereof, and B is selected from cobalt, nickel, copper manganese or mixtures thereof. A method of preparing the selective perovskite catalyst is disclosed as are details of the process for the oxidation of ammonia to nitric oxide.

Claims11

Dependent claims

A process for the selective oxidation of ammonia to nitric oxide in about 90% or greater yield with a minimum of nitrogen or dinitrogen oxide (N.sub.2 O) as by-products, which process comprises:

(1) contacting gaseous ammonia in an oxygen containing gas optionally with an inert gaseous diluent with a mixed metal perovskite catalyst of the general formula:
ABO.sub.3, wherein:
A is selected from the alkali, alkaline earth, lanthanide, or actinide metals or a mixture of these metals having a relatively large ionic radius, and
B is selected from an element or a combination of elements selected from Groups IB, IVB, VB, VIB, VIIB or VIII of the Periodic Table, wherein the perovskite phase of the catalyst has an equilibrium partial pressure of oxygen at 1000.degree. C. of greater than about 10.sup.-15 bar;
and
(2) heating the reactants of step (1) at greater than about 500.degree. C. under conditions of 10 to 100,000 hr.sup.-1 gas hourly space velocity.

3 more elements

Dependencies are inferred from the claim text.

Selective perovskite catalysts to oxidize ammonia to nitric oxide

Life of this patent

Selective perovskite catalysts to oxidize ammonia to nitric oxide

Life of this patent

Abstract

Claims11