Compound Precursors to Mixed Metal Oxides

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Reactions of one solid with another that occur at room temperature are not common in solid state chemistry. The reaction of metal hydroxides with salts is a particularly unusual example. This reaction they have called salt imbibition and it provides a new synthetic method for the preparation of high surface area (HSA) mixed metal oxides. Such compound precursors can be decomposed to give mixed oxides. Because all reactions can be carried out at low temperature, the products will not sinter and will retain their porous character and relatively high surface area. Compared to commercially available HSA oxides (e.g. aluminas, silicas and zeolites) mixed metal oxides offer an entirely new range of materials for applications in ceramics, catalysis and emerging materials science applications. Because HSA mixed oxides have not been widely available their surface chemistry is unknown. Ion-exchange, a diffusion dependent reaction, occurs not only near the surace but can be an important reaction in the interior of a mixed metal oxide crystallite. A related intrinsic characteristic of a HSA oxide is its solid-acid chemistry. To distinguish the type of surface chemistry that can be expected from these novel materials well known reactions such as the isomerization of 3,3-dimethylbutene to 2,3- dimethylbutenes, 2- and 3-methylpentenes, and n-hexenes will be investigated.