Abstract: A catalyst for removing nitrogen oxides from an exhaust gas comprises a composite oxide or mixture of niobic acid or niobium oxide with iron oxide or hydrated iron oxide. The catalyst contains atoms of niobium and atoms of iron in a ratio Nb/Fe not exceeding about 1. The catalyst is useful for converting nitrogen oxides in an exhaust gas to nitrogen gas by contacting the exhaust gas with the catalyst in the presence of a reducing gas, such as ammonia. The catalyst can be prepared by impregnation or coprecipitation.
Abstract: A solid state catalyst consists essentially of hydrated niobium oxide containing a phosphoric acid on its surface in an amount sufficient to increase surface acidity, to inhibit crystallization of the niobium oxide and to retard loss in catalytic activity following exposure to high temperature. The catalyst can be prepared by treating hydrated niobium oxide (Nb.sub.2 O.sub.5.xH.sub.2 O) or an anhydride thereof with a phosphoric acid. The catalyst is useful in the hydration of ethylene to form ethanol.
Type:
Grant
Filed:
August 21, 1985
Date of Patent:
March 24, 1987
Assignee:
CBMM Internacional Ltda.
Inventors:
Susumu Okazaki, Tokio Iizuka, Satoshi Kado
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