Effect of irradiation and of replacement of hydrogen by deuterium on the kinetics of hydrogenation of maleic acid on a nickel catalyst

1980 ◽  
Vol 45 (6) ◽  
pp. 1632-1638 ◽  
Author(s):  
Rostislav Kudláček ◽  
Růžena Jelínková
Keyword(s):  
Reaction Rate ◽  
Catalyst Surface ◽  
Catalyst Activity ◽  
Hydrogenation Reaction ◽  
Gamma Dose ◽  
Model Reaction ◽  
Solid Catalyst ◽  
Liquid Phase Hydrogenation ◽  
Kinetics Of ◽  
Preliminary Irradiation

Liquid phase hydrogenation reaction was studied on modifying the solid catalyst by preliminary irradiation and replacing the reacting hydrogen by deuterium; the changes in the reaction rate were measured and the phenomena on the catalyst surface, particularly the change in the catalyst activity, were investigated. For the model reaction, the dependences of the reaction rate on the temperature of reduction and of the successive activation of the catalyst on the absorbed gamma dose were followed, and the dependences of the reaction rate on the reaction temperature were compared for the hydrogenation and deuteration. Isotope effect was found in the influence of the reacting medium on the catalyst property. The activity of the nickel carrier catalyst is governed by its interaction with hydrogen after the reduction, particularly by the temperature of this process.

Kinetics of carbon monoxide methanation on a Ni/SiO2 catalyst

1990 ◽  
Vol 55 (7) ◽  
pp. 1678-1685
Author(s):  
Vladimír Stuchlý ◽  
Karel Klusáček
Keyword(s):  
Carbon Monoxide ◽  
Reaction Rate ◽  
Catalyst Activity ◽  
Adsorbed Hydrogen ◽  
Reaction Products ◽  
Co Methanation ◽  
Molar Ratios ◽  
Rate Determining Step ◽  
Higher Temperature ◽  
Kinetics Of

Kinetics of CO methanation on a commercial Ni/SiO2 catalyst was evaluated at atmospheric pressure, between 528 and 550 K and for hydrogen to carbon monoxide molar ratios ranging from 3 : 1 to 200 : 1. The effect of reaction products on the reaction rate was also examined. Below 550 K, only methane was selectively formed. Above this temperature, the formation of carbon dioxide was also observed. The experimental data could be described by two modified Langmuir-Hinshelwood kinetic models, based on hydrogenation of surface CO by molecularly or by dissociatively adsorbed hydrogen in the rate-determining step. Water reversibly lowered catalyst activity and its effect was more pronounced at higher temperature.

scholarly journals KINETICS OF HYDROGENATION OF NITROBENZENE, 4-NITROTOLUENE, 4-NITROANILINE AND 2-CHLORO-4-NITROANILINE ON SUPPORTED PALLADIUM CATALYST

2018 ◽  
Vol 59 (4) ◽  
pp. 68
Author(s):  
Alexander A. Krasnov ◽  
Adele R. Latypova ◽  
Olga V. Lefedova ◽  
Nikolaiy Yu. Sharonov ◽  
Evgeniy V. Efremov ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Aqueous Solutions ◽  
Nitro Compound ◽  
Palladium Catalyst ◽  
Reaction Rate ◽  
Supported Palladium Catalyst ◽  
Liquid Phase Hydrogenation ◽  
Donor Acceptor ◽  
Supported Palladium ◽  
Kinetics Of

A study of the kinetics of liquid phase hydrogenation of nitrobenzene, 4-nitrotoluene, 4-nitroaniline and 2-chloro-4-nitroaniline on supported palladium catalyst in aqueous solutions of 2-propanol of different composition was carried out. The influence of the substituent on the value of the total amount of hydrogen absorbed during the reaction and the kinetics of the hydrogenation of substituted nitrobenzenes was discussed. It was found out that the reaction selectivity to 2-chloro-1,4-phenylenediamine decreases due to by-reaction dehalogenation. The degree of dehalogenation depends on the composition of solvent and may be approximately estimated by the values of the absorbed hydrogen volume during the reaction. Also, the presence of the donor-acceptor substituents is capable of exerting influence on the reaction rate of hydrogenation of the nitro compound.

scholarly journals Kinetics of heterogeneous methanolysis of sunflower oil with CaO∙ZnO catalyst: Influence of different hydrodynamic conditions

2014 ◽  
Vol 20 (3) ◽  
pp. 425-439 ◽  
Author(s):  
Ivana Lukic ◽  
Zeljka Kesic ◽  
Svetolik Maksimovic ◽  
Miodrag Zdujic ◽  
Jugoslav Krstic ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Rate Constant ◽  
Sunflower Oil ◽  
Reaction Rate ◽  
Catalyst Surface ◽  
Reaction Rate Constant ◽  
Molar Ratio ◽  
Model Parameters ◽  
Pseudo First Order Reaction ◽  
Kinetics Of

The kinetics of heterogeneous methanolysis of sunflower oil was studied at 60?C using mechanochemically synthesized CaO?ZnO as catalyst. Influence of agitation speed, catalyst amount and methanol to oil molar ratio on the rate of reaction was analyzed. The rate of the process depends on the two resistances - mass transfer of triglycerides to the catalyst surface and chemical reaction on the catalyst surface, which are defined as the values of the overall triglyceride volumetric mass transfer coefficient, kmt,TG, and the effective pseudo first-order reaction rate constant, k, respectively. These kinetic parameters actually determine the value of the apparent reaction rate constant, kapp, whose change with time is defined with the change of triglyceride (TG) conversion. The kinetic model was proposed and the model parameters determined.

Numerical Simulation of an Industrial Fluid Catalytic Cracking Regenerator

2013 ◽  
Author(s):  
Guangwu Tang ◽  
Armin Silaen ◽  
Bin Wu ◽  
Chenn Q. Zhou ◽  
Dwight Agnello-Dean ◽  
...  
Keyword(s):  
Chemical Reactions ◽  
Catalytic Cracking ◽  
Catalyst Surface ◽  
Solid Phase ◽  
Catalyst Activity ◽  
Cylindrical Vessel ◽  
Fluid Catalytic Cracking ◽  
Solid Catalyst ◽  
Momentum Exchange ◽  
Two Phases

Fluid catalytic cracking (FCC) is one of the most important conversion processes in petroleum refineries, and FCC regenerator is a key part of an FCC unit to recover the solid catalyst activity by burning off the deposited coke on the catalyst surface. In modern FCC units, regenerator is a cylindrical vessel. Carrier gas transports the solid catalyst from the stripper and feeds the catalyst into the regenerator through catalyst distributors. The catalyst is fluidized by the air that is injected into the regenerator through air rings in the bottom part of the cylindrical vessel. A three-dimensional multi-phase, multi-species reacting flow computational fluid dynamics (CFD) model was established to simulate the flow inside an FCC regenerator. The two phases involved in the flow are gas phase and solid phase. The Euler-Euler approach, where the two phases are considered to be continuous and fully inter-penetrating, is employed. The model includes gas-solid momentum exchange, gas-solid heat exchange, gas-solid mass exchange, and chemical reactions. Chemical reactions incorporated into the model simulate the combustion of coke which is present on the catalyst surface. The simulation results show a good agreement with plant data.

Hydrogenation Kinetics of N-Ethylcarbaozle as a Heteroaromatic Liquid Organic Hydrogen Carrier

2014 ◽  
Vol 953-954 ◽  
pp. 981-984 ◽  
Author(s):  
Ming Yang ◽  
Yuan Dong ◽  
Han Song Cheng
Keyword(s):  
Activation Energy ◽  
High Temperature ◽  
Hydrogen Pressure ◽  
Reaction Rate ◽  
Hydrogenation Reaction ◽  
First Order ◽  
First Order Kinetics ◽  
Hydrogenation Kinetics ◽  
Hydrogen Carrier ◽  
Kinetics Of

The catalytic hydrogenation kinetics of N-ethylcarbazole over 5 wt% Ru/Al2O3 was investigated at various temperatures. The results shows that the hydrogenation reaction was exothermic and high temperature is unfavorable for the reaction rate. Fully hydrogenation was achieved within 1 hour under the best reaction temperature of 170 °C. The kinetics of N-ethylcarbazole follows the first-order kinetics in terms of the reactant concentration but independent of hydrogen pressure, which was maintained as a constant in the reaction process. The apparent activation energy of N-ethylcarbazole hydrogenation reaction at 150-180 °C was found to be 71.2 kJ/mol.

scholarly journals Highly Efficient Liquid-Phase Hydrogenation of Naringin Using a Recyclable Pd/C Catalyst

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 46
Author(s):  
Jiamin Zhao ◽  
Ying Yuan ◽  
Xiuhong Meng ◽  
Linhai Duan ◽  
Rujin Zhou
Keyword(s):  
Catalytic Activity ◽  
Liquid Phase ◽  
Sodium Hydroxide ◽  
Catalyst Surface ◽  
Hydrogenation Reaction ◽  
Hydrogenation Process ◽  
Highly Efficient ◽  
Liquid Phase Hydrogenation ◽  
Palladium On Carbon

A highly efficient liquid-phase hydrogenation reaction using a recyclable palladium on carbon (Pd/C) catalyst has been used for the transformation of naringin to its corresponding dihydrochalcone. The effects of various solvents on the hydrogenation process were studied, with water being identified as the optimal solvent. The analysis also revealed that sodium hydroxide (NaOH) can accumulate on the surface of the Pd/C catalyst in alcoholic solvents, leading to its inactivation. The higher solubility of NaOH in water implies that it remains in solution and does not accumulate on the Pd/C catalyst surface, ensuring the catalytic activity and stability.

STUDYING THE KINETIC CHARACTERISTICS OF THE EXTRACTION OF ANTHOCYANINS FROM THE SQUEEZE OF KRASNOSTOP ZOLOTOVSKY

2020 ◽  
Author(s):  
M.A. Egyan ◽  
Keyword(s):  
Reaction Rate ◽  
Sugar Content ◽  
Extraction Process ◽  
Efficiency Coefficient ◽  
Kinetic Characteristics ◽  
Reaction Rate Constants ◽  
Solids Content ◽  
Kinetics Of ◽  
Process Speed

The article shows studies characterizing the quality of the squeeze: the mechanical composition of the squeeze is determined, the structural moisture of each component is determined, the sugar content in the formed process of sedimentation of the juice and its acidity are determined refractometrically. The kinetics of anthocyanins extraction was determined in two ways, the solids content in the extract was calculated, and the reaction rate constants of the extraction process and the efficiency coefficient of ultrasonic amplification of the extraction process speed were calculated.

Thermal Decomposition Kinetics of Glyphosate (GP) and its Metabolite Aminomethylphosphonic Acid (AMPA)

2019 ◽  
Author(s):  
Milad Narimani ◽  
Gabriel da Silva
Keyword(s):  
Thermal Decomposition ◽  
Reaction Rate ◽  
Decomposition Kinetics ◽  
Rate Theory ◽  
Thermal Decomposition Mechanism ◽  
Treatment Processes ◽  
Aminomethylphosphonic Acid ◽  
Reaction Rate Theory ◽  
Decomposition Chemistry ◽  
Kinetics Of

Glyphosate (GP) is a widely used herbicide worldwide, yet accumulation of GP and its main byproduct, aminomethylphosphonic acid (AMPA), in soil and water has raised concerns about its potential effects to human health. Thermal treatment processes are one option for decontaminating material containing GP and AMPA, yet the thermal decomposition chemistry of these compounds remains poorly understood. Here, we have revealed the thermal decomposition mechanism of GP and AMPA by applying computational chemistry and reaction rate theory methods. <br>

Particle Destabilization in Turbulent Pipe Flow

1989 ◽  
Vol 21 (6-7) ◽  
pp. 435-442 ◽  
Author(s):  
B. Döll
Keyword(s):  
Pipe Flow ◽  
Reaction Rate ◽  
Turbulent Pipe Flow ◽  
Cationic Polymers ◽  
Flow Conditions ◽  
Polyelectrolyte Adsorption ◽  
Charge Neutralization ◽  
Silica Suspensions ◽  
Kinetics Of ◽  
Turbulent Flow Conditions

Silica suspensions (pH = 6.8) and three different cationic polymers were used to study the kinetics of charge neutralization by polyelectrolyte adsorption. The experiments were performed in a continuous flow pipe reactor under steady state turbulent flow conditions. The charge neutralization was monitored by electrophoretic mobility (EPM) measurements of the suspended particles as a function of time after polyelectrolyte audition. The results show the dependency of the destabilization reaction rate on flow and polymer characteristics.

Cyclization and acid-catalyzed hydrolysis of O-benzoylbenzamidoximes

1986 ◽  
Vol 51 (12) ◽  
pp. 2786-2797
Author(s):  
František Grambal ◽  
Jan Lasovský
Keyword(s):  
Reaction Rate ◽  
Kinetic Isotope ◽  
Acid Base Equilibrium ◽  
Mineral Acids ◽  
Kinetics Of Formation ◽  
Acid Catalyzed ◽  
Ph Scale ◽  
Kinetics Of ◽  
Hydrolysis Of ◽  
Derivatives Of

Kinetics of formation of 1,2,4-oxadiazoles from 24 substitution derivatives of O-benzoylbenzamidoxime have been studied in sulphuric acid and aqueous ethanol media. It has been found that this medium requires introduction of the Hammett H0 function instead of the pH scale beginning as low as from 0.1% solutions of mineral acids. Effects of the acid concentration, ionic strength, and temperature on the reaction rate and on the kinetic isotope effect have been followed. From these dependences and from polar effects of substituents it was concluded that along with the cyclization to 1,2,4-oxadiazoles there proceeds hydrolysis to benzamidoxime and benzoic acid. The reaction is thermodynamically controlled by the acid-base equilibrium of the O-benzylated benzamidoximes.

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