Rare-earth-manganese oxidation catalysts and process of producing same

The process of producing a rare earth-manganese oxidation catalyst by ion exchange reaction, consisting essentially of the steps of:

• (a) introducing finely-divided alkali metal delta manganese dioxide hydrate into an aqueous solution of rare earth metal salt ions to form a reaction suspension, said suspension having a pH of from 5.5 to 6.5, the rare earth metal ions being provided by one or more rare earths of the ceria subgroup;
• (b) reacting said manganese dioxide in said suspension with said rare earth metal ions at a temperature of from 30.degree. to 75.degree. C. and at acid pH's of not over 6.5;
• (c) continuing said reaction until the reaction product contains not over 0.03 moles of total bound potassium and sodium per mole of manganese and approximately one mole of total ceria group rare earth metal per each six moles of manganese;
• (d) separating said reaction product from said aqueous solution;
• and
• (e) preparing dried porous catalytic pellets from said reaction product by forming a paste from a mixture of said reaction product in hydrate form and water-containing particulate bentonite, extruding said paste to form pellets, and drying said pellets to a porous non-agglomerating condition.

The process of producing a rare earth-manganese oxidation catalyst by ion exchange reaction, consisting essentially of the steps of:

• (a) introducing finely-divided alkali metal delta manganese dioxide hydrate into an aqueous solution of rare earth metal salt ions to form a reaction suspension, said suspension having a pH of from 5.5 to 6.5, the rare earth metal ions being provided by one or more rare earths of the ceria subgroup;
• (b) reacting said manganese dioxide in said suspension with said rare earth metal ions at a temperature of from 30.degree. to 75.degree. C. and at acid pH's of not over 6.5;
• (c) continuing said reaction until the reaction product contains not over 0.03 moles of total bound potassium and sodium per mole of manganese and approximately one mole of total ceria group rare earth metal per each six moles of manganese;
• (d) separating said reaction product from said aqueous solution;
• and
• (e) preparing dried porous catalytic pellets from said reaction product by forming a paste from a mixture of said reaction product in hydrate form and partially peptized particulate hydrated alumina, extruding said paste to form pellets, and drying said pellets to remove water.