Reduction using metals

Sodium-naphthalene reduction of organotrineopentoxyphosphonium salts led to the instantaneous loss of phosphonium ion phosphonates and phosphites were obtained748 (reaction 224). Alkali metal amalgams are efficient reagents for the reductive cleavage of both achiral and optically active phosphonium salts configuration is retained750 (Table 23). 

In the reductive cleavage of salts containing both benzyl and tm-butyl substituents, cleavage of the latter predominates (85% versus 15%). That solvents are influential in 

TABLE 23. Reductive cleavage of benzylmethylphenyl-n-propylphosphonium bromide to methyl-phenyl-n-propylphosphine 

Studies using a differential-pulse polarographic technique, which is recommended in place of classical direct current polarography, yielded the following results. For 

Ar3PCH2PhBr, the observed order in the ease of reduction, in aqueous solution at pH 7.00, correlates with the electron-withdrawing ability of the aryl groups (Ar = 2-furyl 2-thienyl phenyl 1-methylpyrrolyl) the first reduction wave would correspond 

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SL Selected Reductions Using Metal Redactor Columns... 

Usually improvement combustion processing or after combustion treatment are used nowadays for NO reduction. However, they are some problems as like a complex, expensive setup, harmness gas emission, and corrosion metal. In recent years, to overcome these problems, some researchers have reported that NO is reduced more effectively use of the adsorption characteristics of activated carbons (ACs) and activated carbon fibers (ACFs) [6-8]. Also, some researchers are studying for NO reduction using metal supported ACs and ACFs by impregnation, metal plating, deposition, and so on [9-13]. However, metal supporting methods on ACs and ACFs in a second and their NO removal efficiency are not studied yet systematically. 

Hydrogenolysis of epoxides to yield alcohols has been much reported in the patent literature, because of its importance as an industrial process, but studies on reactivity and selectivity have not been done systematically. The selectivity is highly dependent on the substituents, as in the case of reduction using metal hydrides. As a metal catalyst, Raney Ni was intensively examined in the early stage. It usually requires high pressures (ca. 100 atm) and temperatures (100 C), as shown in Table 10. Alcohols, benzene, THF and even water have been used as solvents. Accordingly, a hydroxy group in the epoxides remains intact, and hydrocarbons are formed only as by-products. In some cases by-product formation can... 

Chemical methods of degradation include 1) reduction using metals, hydrogen, or metal hydrides 2) oxidation using copper oxide, permanganate, or chlorine and 3) alkaline... 

Stereoselective hydrosiiyiation of terpene ketones such as camphor and menthone catalyzed by Rh(PPh3)3Cl followed by hydrolysis produces different stereochemistry from reductions using metal hydrides . Bulky hydrosilanes favor the production of the more stable alcohols ... 

C. F. Lane, Selective Reductions Using Metal Hydrides , in Aspects of Mechanism and organometallic Chemistry , ed. J. H. Brewster, Plenum Press, New York, 1978, p. 181. 

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