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Supported Metal Halides

Both of the above processes have normally been carried out over supported metal halide catalysts at elevated temperature and pressure. One of the most diflBcult problems has been removing the large quantity of heat generated at the surface of the catalyst by the reaction. If temperature is not adequately controlled in oxychlorination, a serious loss in selectivity will result, and catalyst volatilization will occur. In some cases fluidized solids or moving-bed techniques have been used, but these have generally met with difficulties owing to the volatile nature of the more active metal halide catalysts, such as copper chloride and the corrosive nature of the system. [Pg.169]

Other Friedel-Crafts catalysts are also being developed these include clay-supported metal halides [32] and mesoporous silica supported systems [33], Even enzymes can be used to perform Friedel-Crafts reactions [34]. [Pg.159]

Although the structure of [SsN] has not been established by X-ray crystallography, the vibrational spectra of 30% N-enriched [SsN] suggest an unbranched [SNSS] (5.22) arrangement of atoms in contrast to the branched structure (Dsh) of the isoelectronic [CSs] and the isovalent [NOs] ion (Section 1.2). Mass spectrometric experiments also support the SNSS connectivity in the gas phase.Many metal complexes are known in which the [SsN] ion is chelated to the metal by two sulfur atoms (Section 7.3.3). Indeed the first such complex, Ni(S3N)2, was reported more than twenty years before the discovery of the anion. It was isolated as a very minor product from the reaction of NiCl2 and S4N4 in methanol. However, some of these complexes, e.g., Cu and Ag complexes, may be obtained by metathetical reactions between the [S3N] ion and metal halides. [Pg.100]

The structure of the metal particles dispersed on a silica powder support ( Aerosil 380, 70 A average silica particle diameter) has been studied by Avery and Sanders (47) using electron microscopy in both bright and dark field, to determine the extent to which the metal particles were multiply twinned or of ideal structure. Platinum, palladium, and gold were examined. These catalysts were prepared by impregnation using an aqueous solution of metal halide derivatives, were dried at 100°-150°C, and were hydrogen... [Pg.11]

The use of EM (except in the special case of SEM) demands that the catalyst, whether mono-or multi-phasic, be thin enough to be electron transparent. But, as we show below, this seemingly severe condition by no means restricts its applicability to the study of metals, alloys, oxides, sulfides, halides, carbons, and a wide variety of other materials. Most catalyst powder preparations and supported metallic catalysts, provided that representative thin regions are selected for characterization, are found to be electron transparent and thus amenable to study by EM without the need for further sample preparation. [Pg.198]

A similar type of catalyst including a supported noble metal for regeneration was described extensively in a series of patents assigned to UOP (209-214). The catalysts were prepared by the sublimation of metal halides, especially aluminum chloride and boron trifluoride, onto an alumina carrier modified with alkali or rare earth-alkali metal ions. The noble metal was preferably deposited in an eggshell concentration profile. An earlier patent assigned to Texaco (215) describes the use of chlorinated alumina in the isobutane alkylation with higher alkenes, especially hexenes. TMPs were supposed to form via self-alkylation. Fluorinated alumina and silica samples were also tested in isobutane alkylation,... [Pg.292]

Recent work (Brown and Pearsall, 15) has indicated that while hydrogen aluminum tetrachloride is nonexistent, interaction of aluminum chloride and hydrogen chloride does occur in the presence of substances (such as benzene and presumably, olefins) to which basic properties may be ascribed. It may be concluded that while hydrogen aluminum tetrachloride is an unstable acid, its esters are fairly stable. Further evidence in support of the hypothesis that metal halides cause the ionization of alkyl halides (the products of the addition of the hydrogen halide promoters to the olefins) is found in the fact that exchange of radioactive chlorine atoms for ordinary chlorine atoms occurs when ferf-butyl chloride is treated with aluminum chloride containing radioactive chlorine atoms the hydrogen chloride which is evolved is radioactive (Fair-brother, 16). [Pg.28]

Cuello, J. D., Yang, Y, Ono, E., Jordan, K. A. Nakamura, T. (2000). Hybrid solar and xenon-metal halide lighting for lunar and Martian bioregenerative life support. Soc. Automotive Eng. Tech. Paper 2000-01-2426. [Pg.491]

Direct Reaction of Metal Halide with Support... [Pg.202]

The direct reaction of a metal halide has been used to introduce cobalt(II) and nickel(II) onto polymeric phosphine supports (3),... [Pg.202]

More VEELS or RAIRS investigations of the decomposition of methylene halides on metal single-crystal surfaces and infrared work on alumina-supported metals would be welcome. [Pg.220]

The first general comment relates to the solvent system. In those cases where the electrolysis substrate does not exist in an aqueous-ethanolic or methanolic solution in a suitable ionic form, it is necessary to provide a solvent system of low electrical resistance which will dissolve the substrate, and also a supporting electrolyte whose function is to carry the current between the electrodes. Examples of such solvents are dioxane, glyme, acetonitrile, dimethylformamide and dimethyl sulphoxide supporting electrolytes include the alkali metal halides and perchlorates, and the alkylammonium salts (e.g. perchlorates, tetrafluoro-borates, toluene-p-sulphonates). With these electrolysis substrates, mass transfer to the electrode surface is effected by efficient stirring. [Pg.116]


See other pages where Supported Metal Halides is mentioned: [Pg.251]    [Pg.292]    [Pg.292]    [Pg.292]    [Pg.292]    [Pg.178]    [Pg.108]    [Pg.557]    [Pg.102]    [Pg.62]    [Pg.227]    [Pg.251]    [Pg.292]    [Pg.292]    [Pg.292]    [Pg.292]    [Pg.178]    [Pg.108]    [Pg.557]    [Pg.102]    [Pg.62]    [Pg.227]    [Pg.317]    [Pg.431]    [Pg.18]    [Pg.106]    [Pg.218]    [Pg.222]    [Pg.87]    [Pg.358]    [Pg.323]    [Pg.238]    [Pg.317]    [Pg.196]    [Pg.237]    [Pg.239]    [Pg.78]    [Pg.148]    [Pg.325]    [Pg.119]    [Pg.14]    [Pg.303]    [Pg.225]    [Pg.236]   


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