Monolithic catalysts for conversion of sulfur dioxide to sulfur trioxide

A monolithic catalyst for the conversion of sulfur dioxide to sulfur trioxide comprising a foraminous monolithic ceramic support, said support having at the foraminal wall surfaces thereof a high surface area substrate for an active catalyst phase, and a platinum active phase on said substrate, said substrate comprising high surface area silica and a promoter selected from the group consisting of a compound of zirconium, a compound of titanium or a compound of hafnium.

A monolithic catalyst as set forth in claim 7 wherein said sol comprises a silica sol.

A monolithic catalyst for the conversion of sulfur dioxide to sulfur trioxide comprising a foraminous monolithic ceramic support, said support having at the foraminal wall surfaces thereof a porous silica substrate for an active catalyst phase, and an alkali metal-vanadium active catalyst in the pores of said porous silica.

A process for the preparation of a monolithic catalyst for the oxidation of sulfur dioxide to sulfur trioxide comprising the steps of:

• impregnating a foraminous composite silica substrate with a solution of vanadium compounds and alkali metal salts activable to provide a catalyst for the conversion of sulfur dioxide to sulfur trioxide, said foraminous support having been produced by co-extrusion of a microporous high surface area and a low surface area silica, said support being permeable to high velocity flow of a gas containing sulfur dioxide and oxygen;
• drying the impregnated support, thereby depositing an active catalyst mixture of alkali metal and vanadium compounds in the micropores of said microporous silica;
• contacting the surfaces of said active catalyst mixture with a stream of air containing an oxide of sulfur selected from the group consisting of sulfur dioxide and sulfur trioxide at temperature above about 400.degree. C. to activate the catalyst.

A monolithic catalyst for the conversion of sulfur dioxide to sulfur trioxide comprising a foraminous monolithic ceramic support, a silica washcoat on the foraminal wall surfaces of said support and bound to said walls by a calcined silica sol, and a platinum active phase on said washcoat.

A monolithic catalyst for the conversion of sulfur dioxide to sulfur trioxide comprising a foraminous monolithic ceramic support, said support having at the foraminal wall surfaces thereof a high surface area substrate for an active catalyst phase, and a highly dispersed platinum active phase on said substrate, said platinum active phase having been deposited on said substrate from a solution containing a precursor complex selected from the group consisting of Pt(NH.sub.3).sub.4.sup.++ and Pt(SO.sub.3).sub.2 OH.sup.3-.