Rhone-poulenc Chimie

Rhodia Chimie

Philippe Barthe

Thierry Seguelong

Pierre Macaudiere

Catherine Hedouin

Jacques Lemaire

Dennis Petta

The invention relates to a process for the treatment of gases with high oxygen content, with a view to controlling nitrogen oxide emissions, characterized in that use is made of a catalytic composition comprising manganese oxide and at least one oxide chosen from cerium oxide and zirconium oxide. This composition may furthermore comprise at least one other element chosen from those in groups VIII, IB, IVB and VB. The process of the invention applies in particular to the treatment of exhaust gases of internal-combustion engines, more particularly diesel engines or lean-burn engines.

Process for the treatment of gases with high oxygen content, with a view to controlling nitrogen oxide emissions, using a catalytic composition comprising cerium oxide and/or zirconium oxide

Oxygen-rich exhaust gases, for example those emanating from internal combustion engines, e.g., diesel engines, are catalytically treated/converted to reduce emissions of NO.sub.x, in the presence of a catalytically effective amount of a spinel mass oxide essentially having the formula ZnAl.sub.2 O.sub.4 which was prepared by forming a solution or suspension of the salts of the constituent elements of the mass oxide, drying by atomizing the solution or suspension and calcining the salts of the constituent elements of the mass oxide so as to result in the spinel mass oxide.

Spinel-based catalysts for reducing exhaust emissions of NO.sub.x

Process for the filtration and combustion of carbonaceous matter

Oxygen-rich exhaust gases, for example those emanating from internal combustion engines, e.g., diesel engines, are catalytically treated/converted to reduce emissions of NO.sub.x, in the presence of a catalytically effective amount of either (a) a spinel mass oxide essentially having the formula ZnAl.sub.2 O.sub.4, or (b) a normal or inverse spinel oxide other than ZnAl.sub.2 O.sub.4, for example ZnGa.sub.2 O.sub.4, SnZnGa.sub.2 O.sub.4 or MgAl.sub.2 O.sub.4.

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Saint Martin du Tertre, France

Philippe Barthe