An investigation of Cu–Re–ZnO catalysts for the hydrogenolysis of glycerol under continuous flow conditions

Shozi, Mzamo; Dasireddy, Venkata D.B.C.; Singh, Sooboo; Mohlala, Pheladi; Morgan, David; Iqbal, Sarwat; Friedrich, Holger B.

doi:10.1039/c7se00199a

Cited by 17 publications

(16 citation statements)

References 64 publications

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“…This fact is accordance with the XRD results, suggesting that the copper is present in the tungstate structure, and not in a secondary copper oxide phase. Similar results were observed for NiWO4 and ZnWO4 [42][43][44][45]. Table 3 shows the adjusted peaks and hydrogen consumption for the three MWO4…”

Section: Resultssupporting

confidence: 80%

Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

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The oxidation of sulfides to sulfoxides and sulfones provides valuable sulfur-containing chemical compounds that are used in the pharmaceutical agrochemical industry. Although some tungsten catalytic systems have been applied to sulfide oxidation, the most desirable heterogeneous catalytic protocols have not been described. The copper, nickel and zinc tungstates powders obtained by the polymeric precursor method and the evaluation of their catalytic activity in thioanisole oxidation were investigated. Thioanisole was oxidized by hydrogen peroxide to sulfoxides and sulfones and the presence of catalyst accelerates the conversion. Of the three catalysts, copper tungstate was the most efficient in the conversion process followed by nickel tungstate and finally zinc tungstate. The copper tungstate has higher hydrogen consumption, indicating a higher oxygen content on the surface and the ability to increase surface mobility, which increases the conversion and selectivity of the process. The addition of 0.1 mL of hydrogen peroxide enhanced the conversion and increased the amount of sulfone produced. The ideal reaction time was 12 hours and the optimum temperature was 75 °C.

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Section: Resultssupporting

confidence: 80%

Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

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Alencar

Mendonça

et al. 2020

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“…Comparisons of profile (a) and profile (d) indicate that Re addition retards the reduction of ruthenium oxide because peak reduction temperature (T max ) increases from 170 °C in profile (a) to 193 °C in profile (d). This implies an interaction effect between the Ru and Re particles which shifted the reduction peak to the higher temperature [ 22 ]. Shozi et al [ 22 ] also found that the presence of rhenium increased the reduction temperature of Cu-ZnO catalyst.…”

Section: Resultsmentioning

confidence: 99%

“…This implies an interaction effect between the Ru and Re particles which shifted the reduction peak to the higher temperature [ 22 ]. Shozi et al [ 22 ] also found that the presence of rhenium increased the reduction temperature of Cu-ZnO catalyst.…”

Section: Resultsmentioning

confidence: 99%

Aqueous-Phase Hydrogenolysis of Glycerol over Re Promoted Ru Catalysts Encapuslated in Porous Silica Nanoparticles

Yen

2018

Nanomaterials

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Activity improvement of Ru-based catalysts is needed for efficient production of valuable chemicals from glycerol hydrogenolysis. In this work, a series of Re promoted Ru catalysts encapuslated in porous silica nanoparticles (denoted as Re-Ru@SiO2) were prepared by coating silica onto the surface of chemically reduced Ru-polyvinylpyrrolidone colloids, and were used to catalyze the conversion of glycerol to diols and alcohols in water. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), nitrogen adsorption, X-ray photoelectron spectroscopy (XPS) and temperature-programmed reduction (TPR) were used to characterize these nanoparticles. Effects of Ru/Si atomic ratio, Re addition, glycerol and catalyst concentrations, reaction time, temperature, and hydrogen pressure were investigated. Re addition retarded the reduction of ruthenium oxide, but increased the catalyst reactivity for glycerol hydrogenolysis. Due to its greater Ru content, Re-Ru@ SiO2 showed much better activity (reacted at much lower temperature) and more yields of 1,2-propanediol and overall liquid-phase products than Re-Ru/SiO2 (prepared by conventional impregnation method) reported before. The rate of glycerol disappearance exhibited first-order dependence on glycerol concentration and hydrogen pressure, with an activation energy of 107.8 kJ/mol. The rate constant increased linearly with increasing Ru/Si atomic ratio and catalyst amount. The yield of overall liquid-phase products correlated well with glycerol conversion.

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“…In this section we discuss the chemical problem in terms of its reaction mechanism and the experimental results, then formulate the mathematical model using ordinary differential equations. We use a scheme by Shozi et al [14] to formulate the model since we have the experimental data that accompanies the scheme, making it possible to compare the model simulations with experimental results as well as estimate the reaction parameters.…”

Section: The Chemical Problem Mathematical Model and Its Basic Proper...mentioning

confidence: 99%

“…As steps towards this goal, we consider a reaction model in a report by Shozi et al [14] for the hydrogenolysis of glycerol using Cu-Re/ZnO catalyst, from which we derive a system of ODEs that governs the reaction. From the mathematical model we;…”

Section: Introductionmentioning

confidence: 99%

Mathematical Investigations of a Kinetic Model for Glycerol Hydrogenolysis Via Heterogeneous Catalysis

Ndlovu¹,

Shozi²,

Costa³

2022

MATCH

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In this paper we report on some mathematical investigations of the chemical process for the hydrogenolysis of glycerol over a heterogeneous metal catalyst. The main interest of this process is related to the fact that glycerol is produced as a by-product in the production of biodiesel in huge amounts that are expected to exceed the projected demands. This makes the sustainability of biodiesel production depend on the conversion of the glycerol into useful products hence it is a desirable goal to have effective conversion methods. A reaction model from literature is used to derive a system of ordinary differential equations (ODE) which is then analysed using methods from qualitative analysis of ODEs. Numerical solutions of the system are simulated to try and find out the solution’s behaviour in the chemistry point of view. It was found that all solutions of the model converge to some stable limit point in a 2-dimensional plane in the positive cone of the phase space, and the limit point depends on the values of rate constants as well as on the hydrogen to glycerol initial ratios. Even though the results are based on a specific kinetic model, it is hoped that they may help in providing tools for better understanding and description of the reaction.

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An investigation of Cu–Re–ZnO catalysts for the hydrogenolysis of glycerol under continuous flow conditions

Abstract: Rhenium is an effective promoter for ZnO catalysts in glycerol hydrogenolysis by enhancing catalytic activity and producing lower alcohols in good yields.

Cited by 17 publications

References 64 publications

Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

Heterogeneous catalysis for thioanisole oxidation using hydrogen peroxide and Copper, Nickel and Zinc tungstates prepared by the polymeric precursor method

Aqueous-Phase Hydrogenolysis of Glycerol over Re Promoted Ru Catalysts Encapuslated in Porous Silica Nanoparticles

Mathematical Investigations of a Kinetic Model for Glycerol Hydrogenolysis Via Heterogeneous Catalysis

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