Layered inorganic compounds pillaring

Layered crystalline titanates (CT) [Anthony and Dosch, U.S. Patent 5 177 045 (1993)] are pillared with tetraethyl orthosilicate, 3-aminopropyltrimethoxysilane, and aluminum(III) acetylacetonate to prepare porous and high surface area supports for sulfided NiMo catalyst. Tetraethyl orthosilicate or aluminum(III) acetylacetonate intercalated CT are prepared by stepwise intercalation. First, the basal distance is increased by n-alkylammonium ions prior to intercalation with inorganic compounds. However, an aqueous solution of 3-aminopropyltrimethoxysilane can directly pillar CT without first swelling the titanate with n-alkylamine. The catalytic activities for hydrogenation of pyrene of sulfided NiMo supported silica or alumina pillared CT are higher than those of commercial catalysts (Shell324 and AmocatlC). The silicon and aluminum contents of the pillared CT, used as supports, have considerable effects on the catalytic activities and physical properties of the supports. 

Layered metal oxides(e.g. layered titanates, titanoniobates and niobates) intercalated with organic compounds have been extensively studied because of their potential applications in sorption, catalysis and conduction[1-3]. However, there are few studies on the preparation of inorganic oxide-pillared layered metal oxides, which have higher thermal stability than those layered metal oxides prepared by the intercalation of organic compounds[4-6]. He have reported that layered niobate and titanoniobate can react with NH2(CH2)3Si(OC2H3) 3 (abbreviated hereafter as APS) aqueous solution to obtain porous, thermostable silica-pillared layered metal oxides[7,8]. APS is a trialkoxysilane compound, its trialkoxy groups quickly undergo... 

Pillaring is the process by which an inorganic layered compound is transformed into a thermally stable micro- and mesoporous material with retention of the layer structure. The pillared material is a pillared layered solid, or PLS. In the case of clay minerals, one obtains a pillared clay mineral. A PLS is a subgroup of the group of intercalation compounds, which meet the following criteria (1) ... 

A particularly interesting and important development in recent years has been the use of organic compounds as templates when forming porous inorganic phosphate structures, for example, 2D pillared layer or 3D cavity structures. These organic templates dictate the shape and size of the pores which are formed, and they can usually be removed from the inorganic framework afterwards. If their removal results in lattice collapse, the lattice should not be regarded as truly microporous [3]. 

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