Kinetic data from a pulse microcatalytic reactor-hydrogenation of benzene on a nickel catalyst

Facile Access to Polar-Functionalized Ultrahigh Molecular Weight Polyethylene at Ambient Conditions

1. The curves of the temperature dependence of the degree of exchange and hydrogenation of benzene during the simultaneous occurrence of these reactions on a nickel catalyst are of different types. 2. The introduction of a substantial amount of cyclohexane into the initial mixture has no effect upon the degree of hydrogenation of benzene, but it appreciably lowers the degree of exchange at temperatures above 150°. 3. The curves of the isotopic distribution of cyclohexane, formed during the process of hydrogenation (deuteration) of benzene, differ from the curves of the isotopic distribution of the products of exchange both of benzene and of cyclohexane, introduced separately. 4. The observed experimental facts can be explained on the assumption that the reactions of deuterohydrogen exchange and hydrogenation of benzene proceed through different intermediate surface compounds.

Catalytic performance and kinetic modeling of ethylene glycol steam reforming over surfactant-modified Pd–Ni/KIT-6

In this study, kinetics data was obtained for steam reforming reaction of ethane over the nickel catalyst. The variables of steam reforming reaction were reaction temperature, partial pressure of ethane, and mole ratio of steam and ethane. Parameters for the power rate law kinetic model and the Langmuir-Hinshelwood model were obtained from the kinetic data. Also, sizing of steam reforming reactor was performed by using PRO/II simulator. For the steam reforming reaction of ethane, Langmuir- Hinshelwood model determining the reaction rate by the surface reaction was better suited than a simple power rate law kinetic model. On water-gas-shift reaction, power rate law kinetic model was well fitted to the kinetic data. Reactor size can be calculated for production of hydrogen through PRO/II simulation.

The kinetics of the catalytic hydrogenation of benzene on a commercial nickel catalyst (dp=2.65mm) was studied by a differential type of flow reactor.The conversion of benzene is 5-8% for ordinary runs, and the maximum deviation of the catalyst temperature in the bed is less than 8°C.Initial rates of reaction without cyclohexane and the rate for reactants containing some cyclohexane were measured at atmospheric pressure over the following range of conditions.Temperature: 140, 160, 180, 200 and 220 [°C]Partial pressure: pH=0.4-0.9, pB=0.1-0.6 pO=0-0.5 [atm.]Flow rate: 26-31 [gr/cm2hr.]Twelve different mechanisms were presented, and checked by comparing experimental data of initial rates with the characteristic curve of the modified rate equationAs a result, the most plausible rate-controlling step was found to be in the surface reaction between one adsorbed benzene molecule and three adsorbed hydrogen molecules on the same type of active sites.The final equation recommended for the vapor-phase hydrogenation of benzene on a nickel catalyst is as follows;

Bayerite-promoted caustic leaching of single phase NiAl 3 and Co 2Al 9 alloys to produce highly active Raney nickel and Raney cobalt catalysts

Factors influencing the thioresistance of nickel catalysts in aromatics hydrogenation

Incremental Kinetic Identification based on Experimental data From Steady-state Plug Flow Reactors

The effects of solvents on the hydrogenation of benzene and pyridine have been studied with nickel catalysts supported by active carbon, alumina, and silica. In the case of benzene, the effects of solvents were almost independent of the nature of the carriers. The reaction proceeded most rapidly when benezene was hydrogenated in hydrocarbons or without solvents. The reaction was retarded by the solvents having oxygen atoms. In the case of pyridine, the effects of solvents were much different from those observed in the case of benzene. Many of the solvents having oxygen atoms accelerated the reaction. The extent of acceleration varied a little with the nature of supports. Methanol and water were exceptions; in the case of nickel-active carbon catalyst, the accelerating effects were hardly noticed, but in the cases of nickel-alumina and nickel-silica, the solvents strongly retarded the reaction.

Two silica pillared phosphate materials containing different amounts of silica have been used as supports to prepare, by impregnation, two series of metallic nickel catalysts (8, 10 and 15% loading). Thermal programmed reduction curves of nickel show two peaks at ca. 690 and 838 K denoting two different sites for Ni 2+ ions assigned to the external and inner surface, respectively. These high reduction temperatures indicate high dispersion and strong interactions with the supports. XPS analyses show that the reduction degree at 873 K (2 h) ranges between 22.5 and 30%. The metal dispersion and particle size were calculated from hydrogen adsorption isotherms at 298 K. These nickel catalysts are active in the hydrogenation of benzene (at 443 K). In both series of catalysts no correlation between activities and metal dispersion was found, and turnover frequencies indicate an apparent structure sensitivity of the reaction, likely to be due to the presence of superficial unreduced nickel ions. TEM micrographs reveal that deactivation of catalyst occurs by formation of coke and filaments of carbon separating the nickel particles from the pillared materials.

In the development of a pilot unit for studying reactions involving heterogeneous catalysis a nickel catalyst was selected for the initial study, and the hydrogenation of benzene in a fluidized reactor using nickel and nickel oxide supported on silica gel was investigated for the reaction C6H6+ 3 H2→ C6H12at temperatures of 150—220° for the nickel oxide study and 220–275° for nickel, pressures being 25–100 p.s.i.g. and molal ratios of hydrogen to benzene ranging from 0·5 to 3·9. The data were correlated with an equation of the form\documentclass{article}\pagestyle{empty}\begin{document}$ \[r = \frac{{k_e K_{H_2 }^3 K_B p_{H_2 }^3 p_B }}{{\left({1 + K_{H_2 } p_{H_2 } + K_B p_B } \right)^4 }} \] $\end{document}By observing how the history of the catalyst affects its activity some of the known erratic behaviour of nickel catalysts is now better understood. The reported rate equation and constants for various activity levels for nickel catalyst enable a more intelligent design of chemical reactors employing this catalyst.

Catalytic decomposition of hydrocarbons on cobalt, nickel and iron catalysts to obtain carbon nanomaterials

On the mechanism of CH 3OH oxidation to CH 2O over MoO 3Fe 2(MoO 4) 3 catalyst

Surface and Chemisorption Properties of Small Nickel Particles as Studied by High Field Magnetic Methods, and Catalytic Activity with Respect to Ethane Hydrogenolysis and Benzene Hydrogenation.

Benzene hydrogenation over nickel catalysts at low and high temperatures: Structure-sensitivity and copper alloying effects