Toa Nenryo Kogyo Kabushiki Kaisha

Eiichiroh Nishikawa

Takuji Itoh

Tsugio Maeshima

Setsuo Kamiyama

Tadashi Miura

Mitsuko Nakamura

Takashi Yamahata

Nitrogen oxides are removed from gaseous mixtures comprising the same by contacting with a catalyst comprising a base metal component carried on a natural or synthetic zeolite in the presence of ammonia. The alkali metal content of the zeolite is carefully controlled through ion exchange with an alkaline earth metal compound.

Catalyst for reduction of nitrogen oxides and process for preparing same

Improved distribution of the tin component of a hydrocarbon conversion catalyst also containing a Group VIII noble metal and halogen on a carrier is obtained by impregnation of the carrier with a solution of an acid amide or derivatives thereof and a soluble tin compound.

Method for preparing hydrocarbon conversion catalyst using acid amide

Process for removing nitrogen oxides from gaseous mixtures comprising the same. Ammonia in an amount excessive over the stoichiometric amount necessary for reducing the nitrogen oxides is introduced into a reaction zone containing a catalyst. Then, ammonia in a minimum amount necessary for reduction of the nitrogen oxides is introduced into the reaction zone.

Methods for catalytic reduction of nitrogen oxides

Improved distribution of the tin component of a hydrocarbon conversion catalyst also containing a Group VIII noble metal and halogen on a refractory carrier is obtained by impregnation of the carrier with a solution comprising an organic solvent containing a hydrogen halide and a soluble compound of tin.

Method for preparing hydrocarbon conversion catalyst

Nitrogen oxides are removed from gas mixtures containing nitrogen oxides and oxygen by adding a reducing agent that is a C.sub.2 to C.sub.6 olefin or an aromatic hydrocarbon such as benzene or toluene, preferably butene-1, and contacting the mixture at 200.degree. to 450.degree. C with a catalyst comprising iridium or a compound thereof supported on a refractory carrier, preferably alumina.

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Ohi, Japan

Eiichiroh Nishikawa