Silica compounds intercalation

Immobilized cobalt(II) and zinc(II)phthalocyanine anchored on silica or intercalated in the galleries and cavities of layered double hydroxides (hydrotalcite) and NaX zeoMte catalyze or photocatalyze the oxidation of 2-mercaptoethanol and sodium thiosulfate. The activity of the immobilized catalysts for oxidation and photooxidation is lower than that of the complexes in homogeneous phase. This is due to the hindered diffusion of dioxygen and sulfur-containing compounds to the active catalyst sites. 

X-Ray studies confirm that platinum crystallites exist on carbon supports at least down to a metal content of about 0.03% (2). On the other hand, it has been claimed that nickel crystallites do not exist in nickel/carbon catalysts (50). This requires verification, but it does draw attention to the fact that carbon is not inert toward many metals which can form carbides or intercalation compounds with graphite. In general, it is only with the noble group VIII metals that one can feel reasonably confident that a substantial amount of the metal will be retained on the carbon surface in its elemental form. Judging from Moss s (35) electron micrographs of a reduced 5% platinum charcoal catalyst, the platinum crystallites appear to be at least as finely dispersed on charcoal as on silica or alumina, or possibly more so, but both platinum and palladium (51) supported on carbon appear to be very sensitive to sintering. 

Certain manganese porphyrins adsorbed on silica or alumina, or intercalated in different mineral matrices such as montmorillonite, are also very efficient in alkane hydroxylation.150 151 Alcohol yields and alcohol ketone ratios are remarkably higher than those obtained with the corresponding soluble manganese porphyrins. Manganese tetra(4-Al-methylpyridiniumyl)porphyrin supported on montmorillonite, for instance, is efficient in the hydroxylation of compounds of low reactivity such as n-pentane and n-heptane.151... 

Layered silica clays are recognized for their ability to form a variety of pillared intercalated derivatives with properties for occluding organic compounds and metal complexes, including organometallic clusters (158). These materials consist of positive charged Mg(OH)2-like layers separated by hydrated gallery anions. 

The intercalation compound FeOCl(apy) 4, 80 mg, is soaked in 2 mL of methanol (previously dried over 3A molecular sieves for 3 days) in a sealed Pyrex glass tube, which is typically 10 cm long and 0.8 cm in diameter, with a wall thickness of 2.0 mm.3 The tube is maintained at 100° and shaken twice daily for 10 days. (If difficulty is encountered in obtaining intercalation, it may be helpful to add a small amount of APy.) The resulting brown solid is collected by filtration, washed with several volumes of dry methanol, then stored in a desiccator with silica gel. 

Zirconium phosphate, besides the traditional intercalation processes, has been used to produce pillared compounds, such as those involving mixed Fe-Cr oxides [3]. Furthermore, it has been shown [4] that the protonic conductivity of a-zirconium phosphate can be enhanced by the formation of a composite with alumina or silica, an example of synergic cooperation between the oxides and phosphates which are the main classes of compounds highhghted in the book. 

The effectiveness of organoclay in NR was observed and reported by Carli et They evaluated the technical feasibility of NR nanocomposites with Cloisite 15A, a commercial organoclay to substitute conventional silica (Si02) filler. TEM analysis indicated that the OMt was homogeneously dispersed in the rubber matrix. A shift of the characteristic peaks to lower angles was observed in XRD, attributed to the intercalation of the OMt by macromolecular rubber chains. Based on the mechanical properties of the compounds they concluded that 50 phr of silica can be replaced by 4 phr of OMt with a reduction in the filler content by 12.5 times, without adversely affecting the tensile properties of the final material even after ageing. 

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... 

Free or supported alkali metals readily dimerize propene to a mixture of 2-methylpentenes at 420 — 470 K and 7.0 MPa. As support materitds, silica, a-alumina, oxides or carbonates of alkali and alkaline earth metals are used. The compounds of graphite intercalated by the alkali metals are also used. ... 

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