Ethanol, olefin hydrogenation

The Reduction of 2. Complex 2 (32.0 mg, 0.0457 mmole) was placed either with or without an equivalent (12 mg) of triphenylphosphine in a round-bottom flask under an inert atmosphere. A 1 1 benzene—ethanol mixture (20 ml) was added, and the resultant mixture stirred under hydrogen or nitrogen until complete solution was effected (2-48 hrs). Aliquots of these solutions were used directly for olefin hydrogenation. 

From a charge of RhCljjSHjO, NaBH4, and MClj (M = Ni or Co) in ethanol, (CojBlioRhH and (NijBlioRhHxs have been isolated. These materials catalyse olefin hydrogenation, hydrogenolysis of alkenes, and CO methanation. 

For evaluation of catalytic efficiency, the specific reaction employed was the hydrogenation of a-octene-1 in ethanol solution. The reference material chosen was Harshaw 0104 P (a nickel catalyst on kieselguhr manufactured for olefin hydrogenations). For both catalysts, the conversion of octene-1 to octane was measured by gas-liquid chromatography (GLC). The results of the catalytic activity measurements indicated that the PEO-protected nickel catalyst is comparable to the commercial Harshaw product. In addition, it could have several advantages, including convenience and greatly increased shelf life. 

The cocatalyst catalyzes the hydrogenation of acetaldehyde to ethanol (see the mechanism of olefin hydrogenation but replace the olefin C=C bond by the C=0 aldehyde bond). Same ref as 16.5. 

Normally, the hydrogenation of a readily hydrogenated double bond occurs over palladium-on-charcoal in ethanol at room temperature and atmospheric pressure. The more difficultly reduced olefins require elevated reaction temperatures and/or pressures for the reaction to proceed at a reasonable rate. The saturation of an 8(14)-double bond is virtually impossible under normal hydrogenation conditions. In order to remove unsaturation at this position it is necessary to first isomerize the double bond to the readily hydrogenated 14 position by treatment with dry hydrogen chloride in chloro-form. ° ... 

Highly stereospecific hydrogenations of acetylenes to cis olefins have been achieved also with nickel (P 2) catalysts in the presence of ethylenediamine as prorrtoter (37 8 55 58,72). The catalyst is prepared by reduction of nickel acetate in ethanol with sodium borohydridefi ). Despite successes (44), the use of nickel is relatively infrequent (51). 

With the excephon of methanol and ethanol, most alcohols are produced from olefins, either through hydration [10] or via a hydroformylation-hydrogenation sequence (Scheme 4-1) [11]. 

Sodium hydrogen telluride, (NaTeH), prepared in situ from the reaction of tellurium powder with an aqueous ethanol solution of sodium borohydride, is an effective reducing reagent for many functionalities, such as azide, sulfoxide, disulfide, activated C=C bonds, nitroxide, and so forth. Water is a convenient solvent for these transformations.28 A variety of functional groups including aldehydes, ketones, olefins, nitroxides, and azides are also reduced by sodium hypophosphite buffer solution.29... 

Pentanone 3- Pentanone Perchlorates Bromine trifluoride Hydrogen peroxide, nitric acid Carbonaceous materials, finely divided metals particularly magnesium and aluminum, sulfur, benzene, olefins, ethanol, sulfur, sulfuric acid... 

Hj Dj exchange on, 26 39-43 heteropolyanion-supported, 41 230-231 high MiUer index, 26 12-15,35,36 -H-USY zeoUte, 39 186-187 hydrocarbons adsorption, 38 229-230 reactions of cyclopropane, cyclohexane, and n-heptane, 26 51-53 structural effects, 30 25-26 hydrogen adsorption on, 23 15 hydrogenation, 30 281-282 olefins, in ethanol, 30 352-353 in hydrogenation reaction, 33 101 -iron alloys, 26 75 isomerization, 30 2-3 isotope, NMR properties, 33 213,274 kinetic oscillations, 37 220-228 ball models of densely packed surfaces, 37 221-222... 

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