Infrared spectra of some alkylfurans

The possibility of using the region of the C=C and C-H vibrations of the furan ring for the analysis of the structure of substituted furans and the possibility of determining the structure of the side chain in alkylfurans and alkylbenzofurans have been shown.     

Catalytic performance of zinc-supported copper and nickel catalysts in the glycerol hydrogenolysis

Gas-phase catalytic conversion of glycerol to value added chemicals was investigated over zinc-supported copper and nickel catalysts.The addition of aluminum in the support was also investigated in glycerol conversion and the results indicate an increase in the acidity and adsorption capacity for both copper and nickel catalysts.HRTEM and XRD analysis revealed Ni Zn alloy formation in the Ni/ZnO catalyst.The XRD patterns of the prepared Zn Al mixed oxide catalysts show the presence of Gahanite phase(ZnAl_2O_4).In addition,H_2 chemisorption and TPR results suggest a strong metal-support interactions(SMSI)effect between Ni and Zn O particles.Bare supports Zn O and ZnAl(Zn/Al=0.5) were investigated in the glycerol conversion and they did not present activity.Copper supported on ZnO and ZnAl mixed oxide(Zn/Al=0.5)was active towards hydroxyacetone formation.Nickel was active in the hydrogenolysis of glycerol both for C–C and C–O bonds cleavage of glycerol producing CH_4.Strong metal-support interactions(SMSI)between Ni and ZnO has a remarkable suppression effect on the methanation activity during the glycerol conversion.     

落叶松多聚原花色素的Pd/C催化氢解反应研究

以落叶松（IAlrix gmelini）树皮中提取的多聚原花色素为原料,通过Pd／C催化氢解反应制备低聚原花素。研究了反应温度、时间、压力和催化剂用量对低聚原花色素生成率和多聚原花色素转化率的影响。结果表明,采用催化氢解反应可使落叶松多聚原花色素降解为低聚原花色素。以70％乙醇水溶液为介质时的较优反应条件是：反应温度为80℃、反应时间为200min、氢气压力为3MPa、Pd／C催化剂用量为0．2％。在此条件下多聚原花色素的转化速率≥90％,低聚原花色素的生成率≥75％。HPLC分析表明,落叶松多聚原花色素降解产物与葡萄籽低聚原花色素的典型成分一致。     

Catalytic hydrogenolysis of alkyl halides by sulfido-bridged molybdenum clusters: A density functional study

Density functional theory has been used to explore the mechanism of cleavage of H₂ at a sulfido-bridged molybdenum cluster, CpMo(μ-SH)(μ-S)(μ-S₂CH₂)MoCp. The addition occurs across a single Mo-S bond, and the disruption of the strong Mo-S π bonding in the ground state leads to a very high-lying transition state (+43 kcal mol⁻¹). Once formed, the adsorbed hydrogen migrates over the cluster via a series of hops from metal to sulphur, formally corresponding to a switch from hydridic to protic character. The low barrier (+15 kcal mol⁻¹) for migration leads to facile hydrogenolysis of coordinated substrates.     

Catalytic properties of Ni/WS2 samples in thiophene hydrogenolysis

The interaction of diallylnickel with WS₂ produces catalysts whose activity is 10–50 times higher than that of the parent sulfide. The atomic catalytic activity referred to supported nickel is independent of the catalyst type and the sulfur removed in temperature programmed reduction.

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, WS₂ , 10–50 . , , .

     

Highly chemoselective hydrogenolysis of iodoarenes

The catalytic hydrodehalogenation reaction using molecular hydrogen and Pd/C has been revisited. It is shown that the speed of removal of halogen increases with increasing electronegativity I < Br < Cl. Nevertheless, selective dehydrohalogenation in compounds containing other reducible functions can be achieved only with iodine and not with bromine or chlorine. Selective deiodination of iodobenzophenone could be accomplished without reducing the carbonyl group. Hydrogenolysis of azidoiodoaromatic compounds to the corresponding azido compounds is high yielding. This selectivity was exploited for the labeling of benzophenone- and azido-containing compounds by deuterium and tritium.     

The catalytic hydrogenolysis of benzylamine derivatives

The hydrogenolysis of optically active ethyl 2-amino-2-phenylpropionate (I), its N-methyl (II), and N,N-dimethyl (III) derivatives was studied using Raney Ni and Pd as the catalysts. The Raney Ni catalysed hydrogenolysis of II and III, as well as the reaction catalysed by Pd, occurred predominantly with inversion of configuration; this is not in accord with the hydrogenolysis of corresponding benzyl alcohols. This difference can be ascribed to the difference of the affinity for Ni between N and O atoms. The “SN_Ni” process may be inhibited in the Raney Ni catalysed hydrogenolysis of II and III since the amino group acts as a self-catalyst poison, and the “S_N2” process appears to be preferable to the “S_Ni” one. The predominance of the configurationally inversion was also observed in the Pd catalysed hydrogenolysis of I. These results over Pd are reasonable in reflecting that the N atom has not so high affinity for Pd. The hydrogenolysis of a quarternary ammonium bromide of I was also reported.     

Hydrocarbon hydrogenolysis on nickel-tin catalysts

Hydrogenolysis of ethane, n-hexane and cyclohexane has been studied on nickel-kieselguhr catalysts modified by organic and inorganic compounds of tin. Tin additives decrease nickel reactivity with respect to C–C dissociation, which is ascribed to the formation of surface intermetallides on the catalyst.

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, - - , . . C–C .

     

Glycerol hydrogenolysis to propylene glycol

A nickel catalyst showed a considerable selectivity to propylene glycol (up to 98%) at 30% glycerol conversion, under moderate hydrogenation conditions: 200 °C reaction temperature, 20–25 bar hydrogen pressure, 5 wt% catalyst and unprecedented low reaction time of 8 h.     

n-Hexane hydrogenolysis on bimetallic platinum-palladium catalysts

Alumina supported platinum, palladium and bimetallic platinum-palladium catalysts have been investigated in the hydrogenolysis of n-hexane. Results show that, compared with platinum, the activity of bimetallic catalysts is several times lower while the selectivity to hydrogenolytic products increases from 72 to 100%.

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, , , -. , , , 72 100%.