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Effect of solvent on the selectivity of double bond displacement in olefins under conditions of catalytic hydrogenation
Abstract 1. A study was made of the effect of solvent polarity of: n-heptane, ethanol and dimethylformamide on the selectivity of double bond displacement in hex-1-ene, 2-methylpent-1-ene, 3-methylpent-1-ene and 2,3-dimethylbut-1-ene in the presence of palladium black and skeletal nickel at atmospheric pressure and 40°C. 2. α-Hexenes, which differ only in the number of alkyl substituents at the double bond, behave differently in all the solvents examined in hydrogenation and isomerization according to the type of catalyst. In the presence of palladium disubstituted hexenes are isomerized with a higher selectivity than mono-substituted hexenes, while the relationship is the reverse in the presence of nickel. 3. The selectivity of isomerization of α-hexenes in the presence of palladium in polar solvents is higher, while on nickel it is lower than in polar heptane. 4. The varying behaviour of catalysts is, apparently, caused by the varying state of hydrogen absorbed; palladium hydride has positive charge, while nickel hydride—a negative charge. 5. All the regularities observed may be explained by the Horiuti-Polanyi mechanism assuming the formation of two intermediate semi-hydrated forms.
Effect of solvent on the selectivity of double bond displacement in olefins under conditions of catalytic hydrogenation
Abstract 1. A study was made of the effect of solvent polarity of: n-heptane, ethanol and dimethylformamide on the selectivity of double bond displacement in hex-1-ene, 2-methylpent-1-ene, 3-methylpent-1-ene and 2,3-dimethylbut-1-ene in the presence of palladium black and skeletal nickel at atmospheric pressure and 40°C. 2. α-Hexenes, which differ only in the number of alkyl substituents at the double bond, behave differently in all the solvents examined in hydrogenation and isomerization according to the type of catalyst. In the presence of palladium disubstituted hexenes are isomerized with a higher selectivity than mono-substituted hexenes, while the relationship is the reverse in the presence of nickel. 3. The selectivity of isomerization of α-hexenes in the presence of palladium in polar solvents is higher, while on nickel it is lower than in polar heptane. 4. The varying behaviour of catalysts is, apparently, caused by the varying state of hydrogen absorbed; palladium hydride has positive charge, while nickel hydride—a negative charge. 5. All the regularities observed may be explained by the Horiuti-Polanyi mechanism assuming the formation of two intermediate semi-hydrated forms.
Effect of solvent on the selectivity of double bond displacement in olefins under conditions of catalytic hydrogenation
Gostunskaya, I.V. (Autor:in) / Fishbein, V.Yu. (Autor:in) / Dobroserdova, N.B. (Autor:in) / Leonova, A.I. (Autor:in)
19.07.1976
7 pages
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
Hydrogenation of Alkynes and Olefins Catalyzed by Quaternary Ammonium Salts
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