In this work, we describe a catalytic material based on a zirconium-tungsten oxide with ruthenium for the hydrogenolysis of microcrystalline cellulose under hydrothermal conditions. With these catalysts, polyols can be produced with high yields. High and stable polyol yields were also achieved in recycling tests. A catalyst with 4.5 wt% ruthenium in total achieved a carbon efficiency of almost 100%. The prepared Zr-W oxide is mesoporous and largely stable under hydrothermal conditions (493 K and 65 bar hydrogen). Decomposition into the components ZrO2 and WO3 could be observed at temperatures of 1050 K in air.

Um die Wettbewerbsfahigkeit aufrecht zu erhalten gilt es Prozesse stetig zu optimieren. Polyamide gehoren zu den verbreitetsten Kunststoffen weltweit und finden vor allem als Synthesefasern ihre Anwendung. Untersucht wird eine alternative Teilreaktion in der Produktion von Adipinsaure, die Flussigphasenhydratisierung von Cyclohexen zu Cyclohexanol, unter Verwendung des Zeolithen H-ZSM5 als Katalysator. Mit einem Si/Al-Verhaltnis von 28 weist er im optimalen Reaktionsfenster die beste Performance hinsichtlich der Selektivitat und Aktivitat zu Cyclohexanol auf, wodurch eine maximale Ausbeute von 13% erreicht wird.Abstract In order to maintain competitiveness, it is important to constantly optimize processes. Polyamides are among the most widely used synthetics in the world and are used mainly as synthetic fibres in the textile industry. An alternative partial reaction is investigated in the production of adipic acid, the liquid phase hydrationn of cyclohexene to cyclohexanol, using the zeolite H-ZSM5 as a catalyst. With a Si/Al ratio of 28 it was found to offer the best performance regarding selectivity and activity under optimized reaction conditions resulting in cyclohexanol yields of 13%.

The successful application of solid catalyst with ionic liquid layer (SCILL) concept in the selective hydrogenation of propyne is presented in this work. A Pd-based SCILL catalyst was prepared by spray impregnation of commercial available Pd/Al2O3 egg-shell catalyst and characterized by nitrogen sorption. Catalytic testing showed that even small amounts of ionic liquid were sufficient to suppress the consecutive reaction of propane formation, while propene selectivity was increased up to 97%. C6 oligomer formation, which is known to induce deactivation of the catalyst, could be prevented by excess hydrogen in the feed.

Metal borides are unconventional heterogeneous catalysts. Now, two compounds - the new phase Ni7B3 and well-known Co2B - were synthesized as well-defined, nanoscale material. After characterization (X-ray diffraction, scanning electron microscopy, nitrogen physisorption) they were tested for the liquid phase hydrogenation of citral (3,7-dimethyl-2,6-octadienal) in n-hexane at different temperatures. Hydrogenation products such as geraniol, nerol, citronellal and citronellol were analyzed. The Ni-free catalyst Co2B results in the formation of nerol and geraniol or citronellol selectively, depending on the reaction time. The new compound Ni7B3 yields citronellal or citronellol, depending on the temperature. Thus, the hydrogenation potential of borides - obtained as well-characterized, unsupported heterogeneous catalysts by a one-pot synthesis procedure and post-synthetic annealing - is demonstrated. The cobalt boride preferentially hydrogenates C=O bonds, while the nickel boride is selective for C=C double bonds. (C) 2017 Elsevier Inc. All rights reserved.

In the context of sustainable production processes based on bio-derivable feedstocks, the hydrogenolysis of furfuryl alcohol gives access to two important diols. This work evaluates the performance of commercial copper catalysts in the aqueous phase hydrogenolysis reaching a selectivity towards 1,2-pentanediol of up to 34%. In contrast to noble metal catalysts such as supported ruthenium, the selectivity of the hydrogenation product, tetrahydrofurfuryl alcohol, is significantly lower, so the desired diols are now the main products of this reaction. Catalysis experiments show that the performance is correlated to the catalyst composition rather than the free copper surface, indicating a strong influence of the supporting material. Although the formation of oligomeric and polymeric side products is still perturbing, copper catalysts represent promising candidates for this reaction due to their low cost and wide availability.

The article contains sections titled: 1. Cyclopentadiene and Dicyclopentadiene 1.1. Physical Properties 1.2. Chemical Properties 1.3. Production 1.4. Uses 2. Cyclopentene 2.1. Physical Properties 2.2. Chemical Properties 2.3. Production 2.4. Uses 3. Toxicology

We report an advanced experimental setup for the reliable determination of diffusion and solubility, especially for slightly soluble gases in ionic liquids. We were able to improve resolution and reproducibility of an isochoric saturation method by using differential pressure measurements. It was also possible to reduce the influence of wall adsorption, too. For the first time we present diffusion coefficients of hydrogen gas (H2) in the ionic liquids [EMIM][NTf2], [BMIM][NTf2], [HMIM][NTf2], and [OMIM][NTf2] at temperatures between 293.15 and 343.15 K. Henry's Law constants were determined simultaneously by fitting the experimental pressure decay to a one-dimensional diffusion model. With rising temperature, diffusion coefficients and solubility of H2 were increased. Increasing the length of the alkyl side chain of the cation decreased diffusion, whereas solubility of H2 was increased. An empirical correlation equation for H2 diffusion in [CnMIM][NTf2] ionic liquids is presented. Limitations are also pointed out. Furthermore, diffusion and solubility of carbon monoxide and carbon dioxide were investigated in [BMIM][NTf2] and compared to that of H2.

Temperature, pressure, and concentration variation experiments were conducted in the one-pot-transformation of citronellal to menthol with 1%Ru/H-BEA-25 as bifunctional catalyst. This reaction requires a combination of a cyclization and hydrogenation step, therefore the product distribution strongly depends on reaction conditions, especially on the reaction temperature. At lower temperatures the consecutive hydrogenation of citronellal prevails, whereas at high temperatures defunctionalization of menthols is favored leading to a maximum menthol yield at 373 K. A kinetic model was proposed based on a Langmuir–Hinshelwood mechanism and different active sites for cyclization and hydrogenation reactions. Kinetic parameters (reaction constants, activation energies, and adsorption coefficients) were estimated by using nonlinear regression.

In the hydrogenation of carbon dioxide to formic acid, the analysis is a challenge due to the unfavorable position of equilibrium and the complex reaction medium. Low yields, despite the use of a Ru/gamma-Al2O3 catalyst, the formation of formic acid-amine adducts, and subsequent reactions with the solvent complicate the analytics. The coupling of the reactor to the ATR-IR spectroscopy allows precise in situ monitoring of the reaction. Another advantage is the easy accessibility of the initial kinetics. That way, a deviation from the Arrhenius behavior was found.

Selective benzene (BEN) hydrogenation to cyclohexene (CHE) has been studied in a complex four-phase system by using 2Ru/La2O3-ZnO as the catalyst. The catalyst is highly efficient (yield of desired cyclohexene=28%) and stable for about five cycles. Characterizations reveal formation of La(OH)(3) on the catalyst surface and formation of Zn(OH)(3)(-) during the reaction, which play a key role in the formation of CHE. For the first time, the reaction mixture can be observed in situ, showing the emulsion of this complicated four-phase system. The droplet size of the organic compound and the rate of hydrogenation are correlated with different stirring rates excluding mass transfer limitations.

Organosolv fractionation of barley straw followed by a hydrogenolysis reaction of the resulting organosolv pulp over a heterogeneous catalyst containing ruthenium and tungsten on activated carbon (Ru-W/AC) is a potential pathway to produce valuable chemicals from lignocellulose-based feedstock in a future biorefinery. Polyols, such as ethylene glycol, propylene glycol, or 1,2-butanediol, can be obtained with a very high yield of 70 % using organosolv barley pulp pretreated in a 50:50 wt % ethanol/water solution at 200 °C and a processing time of one hour. Moreover, we investigated the influence of several pretreatment parameters (e.g., solvent/water ratio, reaction temperature, and reaction time) on the pulp composition and product distribution obtained during the hydrogenolysis reaction to reduce the production of undesired side molecules. Finally, the optimal organosolv pretreatment conditions for straw were successfully transferred to other lignocellulose-based feedstock, namely bamboo foliage and hemp shives.

The hydrogenation of CO2 to formic acid, heterogeneously catalysed by Ru/g-Al2O3 shows a correlation with the permittivity of the solvent and the solvatochromic parameters a and beta. The effect of different alkyl amines on the activity were evaluated and the outstanding activity of the combination of ethanol and NEt3 was explained by strong interactions, proved by ATR-IR spectroscopy. Furthermore we demonstrated that the hydrogenation of CO2 into ethyl formiate - in the presence of ethanol - doesn't need any amine.

Heterogeneous Ru/H-BEA catalysts are suitable catalysts for the one-pot transformation of citronellal to menthols, which requires a combined cyclization-hydrogenation step. Here, we report the role of different preparation conditions-namely the choice of the Ru-precursor (Ru(NO)(NO3)(3)), Ru(acac)(3), RuCl3 and Ru-3(CO)(12)) as well as the reduction temperature (523-923 K) of the catalyst. Using Ru(NO)(NO3)(3) as precursor the highest activity was obtained, while the product distribution was not strongly affected by the choice of the precursor.On the contrary the reduction temperature leads to very different product distributions: Increasing it from 623 K to 923 K for a 1%Ru/H-BEA-25 catalyst the competitive hydrogenation of citronellal was diminished, which leads to an increased selectivity to menthols from 77% to 87% and additional the activity increases with a factor of 3.4. This behaviour might be due to a dealumination of the zeolite during reduction at higher temperatures. Moreover, in combination with appropriate reaction conditions a yield to menthols of 92% can be reached. (C) 2016 Elsevier B.V. All rights reserved.