Preparation of high surface area agglomerates for catalyst support and preparation of monolithic support structures containing them

DETAILED DESCRIPTION OF THE INVENTION As one aspect of the present invention, an agglomerated, high surface area material is prepared separately for subsequent incorporation into the monolithic catalyst support.
Preparation is carried out by mixing a porous oxide and a binder for the oxide to form a substantially homogeneous composition.
The composition is heated to cure and harden the binder and to drive off other volatiles, and then formed into the coarse particles which will constitute the high surface phase within the ceramic matrix of the present catalyst support.
The porous oxides suitable for use herein are those which, after calcining, have a surface area of at least 20 square meters per gram, preferably at least 60 square meters per gram, and most preferably at least 100 square meters per gram.
(As used herein, "calcining" means heating a material to a temperature below that at which the material begins to substantially lose its porosity and surface area.
) Preferably the oxide is alumina, silica, a spinel, titania, zirconia, or a zeolite.
Mixtures of the oxides can also be used.
The invention is not limited to these particular oxides, however, and as those skilled in the art will recognize, the invention contemplates the use of other materials which are commonly used as catalyst supports and which have the above-described characteristics.
The aluminas useful in the preparation of the high surface area agglomerates of this invention are those which, upon calcining, provide gamma-alumina or other transition aluminas having the specified surface area.
Colloidal gamma-alumina can be used directly, or "alumina-precursors" such as alpha-alumina monohydrate, or aluminum chlorohydrate can also be used.
When alpha-alumina monohydrate is used, the particle size, although not critical, can be from less than 1 micron up to about 100 microns.
Suitable commercially available materials of this kind are Kaiser SA substrate alumina, available from the Kaiser Chemical Division of Kaiser Aluminum Corporation, and the Catapal