Adsorbable organic halogen-containing

Direct evidence for a combination of catalytic fluorination and chlorination [4] was obtained from radiotracer studies in which fluorinated chromia catalysts were labelled with the short-lived (t /2 = 110 min) / + emitting isotope fluorine-18 [11]. Using this isotope it was possible to probe the interactions between HF and various fluorinated chromia catalysts more directly than had been possible hitherto. Three types of surface F-containing species were differentiated, weakly adsorbed HF which was easily removed by an inert gas flow, non-labile F, believed to be bound directly to surface Crin, and catalytically active F which could be incorporated into the organic products [12]. The controversy between dismutation (concerted F-for-Cl and Cl-for-F transfers) and non-concerted halogen exchange processes has been resolved more recently and the evidence is described later in the chapter. What is clear from this early work however, is the importance of aluminium and chromium(III) oxides as catalyst precursors. Fluorination of the surfaces of these oxides is slow (cf [12]) and although there are many references to alu-... 

Some papers have appeared that deal with the use of electrodes whose surfaces are modified with materials suitable for the catalytic reduction of halogenated organic compounds. Kerr and coworkers [408] employed a platinum electrode coated with poly-/7-nitrostyrene for the catalytic reduction of l,2-dibromo-l,2-diphenylethane. Catalytic reduction of 1,2-dibromo-l,2-diphenylethane, 1,2-dibromophenylethane, and 1,2-dibromopropane has been achieved with an electrode coated with covalently immobilized cobalt(II) or copper(II) tetraphenylporphyrin [409]. Carbon electrodes modified with /nc50-tetra(/7-aminophenyl)porphyrinatoiron(III) can be used for the catalytic reduction of benzyl bromide, triphenylmethyl bromide, and hexachloroethane when the surface-bound porphyrin is in the Fe(T) state [410]. Metal phthalocyanine-containing films on pyrolytic graphite have been utilized for the catalytic reduction of P anj -1,2-dibromocyclohexane and trichloroacetic acid [411], and copper and nickel phthalocyanines adsorbed onto carbon promote the catalytic reduction of 1,2-dibromobutane, n-<7/ 5-l,2-dibromocyclohexane, and trichloroacetic acid in bicontinuous microemulsions [412]. When carbon electrodes coated with anodically polymerized films of nickel(Il) salen are cathodically polarized to generate nickel(I) sites, it is possible to carry out the catalytic reduction of iodoethane and 2-iodopropane [29] and the reductive intramolecular cyclizations of 1,3-dibromopropane and of 1,4-dibromo- and 1,4-diiodobutane [413]. A volume edited by Murray [414] contains a valuable set of review chapters by experts in the field of chemically modified electrodes. 

Place recovered petroleum ether in the container for nonhalogenated organic liquids, but pour the recovered dichloromethane into a container for halogenated organic liquids. Spread out the alumina adsorbent, which is wet with organic solvent, in a hood to dry and then place it in the nonhazardous solid waste container. 

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