COMPLEX OF NICKEL (II) ION WITH TRYPTOPHAN AS A HOMOGENEOUS CATALYST IN THE DECOMPOSITION REACTION OF CUMENE HYDROPEROXIDE IN AQUEOUS SOLUTION

2021 ◽  
Vol 55 (2 (255)) ◽  
pp. 118-124
Author(s):  
Gevorg S. Grigoryan
Keyword(s):  
Aqueous Solution ◽  
Kinetic Study ◽  
Arrhenius Equation ◽  
Cumene Hydroperoxide ◽  
Effective Rate Constant ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Effective Rate ◽  
Homogeneous Catalyst ◽  
Kinetic Expression

The formation of Ni2+:Tryptophan (Trp) 1:1 complex, which acts as a model catalyst for decomposition of cumene hydroperoxide (ROOH) in Ni2++Trp+ROOH+H2O system, has been confirmed via kinetic study in aqueous solution at pH>7. The kinetic expression of a single catalytic decomposition reaction of ROOH under the influence of [NiTrp]+ complex was brought out. The temperature dependence of the effective rate constant of ROOH decay (Keff=Kcat[Ni2+]0[Trp]0=const) in the temperature range from 323 to 343 K can be expressed by Arrhenius equation (Eeff is in kJ/mol):  Keff=(1.87±0.02)·106exp[–(49.8±0.3)/RT], min –1.

CATALYTIC ACTIVITY OF THE COBALT(II) ION WITH PHENYLALANINE COMPLEX IN THE DECOMPOSITION REACTION OF CUMENE HYDROPEROXIDE IN AQUEOUS SOLUTION

2020 ◽  
Vol 54 (2 (252)) ◽  
pp. 105-111
Author(s):  
G.S. Grigoryan
Keyword(s):  
Aqueous Solution ◽  
Catalytic Activity ◽  
Kinetic Study ◽  
Decay Rate ◽  
Arrhenius Equation ◽  
Cumene Hydroperoxide ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Effective Constant ◽  
Kinetic Expression

The formation of Cօ2+ : phenylalanine (Phe) 1:1 complex has been confirmed via kinetic study in aqueous solution at pH>7, which acts as a model catalyst for the decomposition of cumene hydroperoxide (ROOH) in Co2++Phe+ROOH+H2O system. The kinetic expression of a single catalytic decomposition reaction of ROOH under the influence of [CoPhe]+ complex, as well as the Arrhenius equation describing the temperature dependence of the effective constant Keff (=Kcat[Co2+]0[Phe]0) of ROOH decay rate in the temperature range from 323 to 343 K are brought out.

KINETICS OF THE CUPRIC ACETATE CATALYZED HYDROGENATION OF DICHROMATE IN AQUEOUS SOLUTION

1955 ◽  
Vol 33 (2) ◽  
pp. 356-364 ◽  
Author(s):  
E. Peters ◽  
J. Halpern
Keyword(s):  
Activation Energy ◽  
Aqueous Solution ◽  
Partial Pressure ◽  
Kinetic Study ◽  
Reaction Rates ◽  
Homogeneous Catalyst ◽  
Cupric Acetate ◽  
Partial Pressures ◽  
Kinetics Of

In aqueous solution, cupric acetate was found to act as a homogeneous catalyst for the reduction of dichromate by hydrogen, i.e.[Formula: see text] The paper describes a kinetic study of this reaction. Rates were determined at temperatures between 80° and 140 °C. and hydrogen partial pressures up to 27 atmospheres. The rate is independent of the dichromate concentration but varies directly with the partial pressure of hydrogen and is nearly proportional to the concentration of cupric acetate. The activation energy is 24,600 calories per mole. Cupric acetate, apparently acting as a true catalyst, activates the hydrogen through formation of a complex with it. An extension of the mechanism proposed earlier for the reaction of cupric acetate itself with hydrogen also accounts for the kinetics of the dichromate reaction.

Sulfur-Induced cis-trans Isomerization of Polybutadiene

1962 ◽  
Vol 35 (2) ◽  
pp. 536-545 ◽  
Author(s):  
William A. Bishop
Keyword(s):  
Double Bond ◽  
Effective Rate Constant ◽  
Effective Rate ◽  
Order Kinetic ◽  
Sulfur Concentration ◽  
Π Complex ◽  
Wide Range ◽  
Kinetic Expression ◽  
Initial Interaction ◽  
Kinetics Of

Abstract Both high cis-1,4-polybutadiene and high trans-1,4-polybutadiene were found to isomerize when heated in the presence of elemental sulfur. The kinetics of the sulfur induced isomerization of high cis-1,4-polybutadiene were studied over a wide range of temperature and sulfur concentration and found to obey a first-order kinetic expression having an effective rate constant directly proportional to the initial sulfur concentration. The apparent activation energy was found to be 30.1 ± 0.4 kcal/mole. Isomerization was also found to be induced by dicumyl peroxide. A comparison of the mechanisms involved in the sulfur and peroxide induced isomerization indicate a basic difference in the nature of the initial interaction of the double bond with the sensitizing species. The initial interaction of the sulfur and the double bond is pictured as a π-complex that decomposes to a freely rotating radical, whereas the peroxide induced isomerization is presumed to involve direct radical addition to the double bond.

scholarly journals Water Splitting and Transport of Ions in Electromembrane System with Bilayer Ion-Exchange Membrane

Membranes ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 346 ◽  
Author(s):  
Stanislav Melnikov ◽  
Denis Bondarev ◽  
Elena Nosova ◽  
Ekaterina Melnikova ◽  
Victor Zabolotskiy
Keyword(s):  
Ion Exchange ◽  
Water Splitting ◽  
Surface Film ◽  
Effective Rate Constant ◽  
Effective Rate ◽  
Limiting Current ◽  
Ion Exchange Membranes ◽  
Bipolar Membranes ◽  
The Matrix ◽  
Exchange Membrane

Bilayer ion-exchange membranes are mainly used for separating single and multiply charged ions. It is well known that in membranes in which the layers have different charges of the ionogenic groups of the matrix, the limiting current decreases, and the water splitting reaction accelerates in comparison with monolayer (isotropic) ion-exchange membranes. We study samples of bilayer ion-exchange membranes with very thin cation-exchange layers deposited on an anion-exchange membrane-substrate in this work. It was revealed that in bilayer membranes, the limiting current’s value is determined by the properties of a thin surface film (modifying layer). A linear regularity of the dependence of the non-equilibrium effective rate constant of the water-splitting reaction on the resistance of the bipolar region, which is valid for both bilayer and bipolar membranes, has been revealed. It is shown that the introduction of the catalyst significantly reduces the water-splitting voltage, but reduces the selectivity of the membrane. It is possible to regulate the fluxes of salt ions and water splitting products (hydrogen and hydroxyl ions) by changing the current density. Such an ability makes it possible to conduct a controlled process of desalting electrolytes with simultaneous pH adjustment.

Thermo-catalytic decomposition of polystyrene waste: Comparative analysis using different kinetic models

2019 ◽  
Vol 38 (2) ◽  
pp. 202-212 ◽  
Author(s):  
Ghulam Ali ◽  
Jan Nisar ◽  
Munawar Iqbal ◽  
Afzal Shah ◽  
Mazhar Abbas ◽  
...  
Keyword(s):  
Activation Energy ◽  
Copper Oxide ◽  
Solid Waste ◽  
Thermodynamic Parameters ◽  
Model Fitting ◽  
Catalytic Decomposition ◽  
Decomposition Reaction ◽  
Inert Atmosphere ◽  
Heating Rates ◽  
Model Free

Due to a huge increase in polymer production, a tremendous increase in municipal solid waste is observed. Every year the existing landfills for disposal of waste polymers decrease and the effective recycling techniques for waste polymers are getting more and more important. In this work pyrolysis of waste polystyrene was performed in the presence of a laboratory synthesized copper oxide. The samples were pyrolyzed at different heating rates that is, 5°Cmin−1, 10°Cmin−1, 15°Cmin−1 and 20°Cmin−1 in a thermogravimetric analyzer in inert atmosphere using nitrogen. Thermogravimetric data were interpreted using various model fitting (Coats–Redfern) and model free methods (Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman). Thermodynamic parameters for the reaction were also determined. The activation energy calculated applying Coats–Redfern, Ozawa–Flynn–Wall, Kissinger–Akahira–Sunose and Friedman models were found in the ranges 105–148.48 kJmol−1, 99.41–140.52 kJmol−1, 103.67–149.15 kJmol−1 and 99.93–141.25 kJmol−1, respectively. The lowest activation energy for polystyrene degradation in the presence of copper oxide indicates the suitability of catalyst for the decomposition reaction to take place at lower temperature. Moreover, the obtained kinetics and thermodynamic parameters would be very helpful in determining the reaction mechanism of the solid waste in a real system.

Kinetic Study of the Diels-Alder Reaction of Cyclopentadiene with Bis(2-Ethylhexyl) Maleate

2013 ◽  
Vol 634-638 ◽  
pp. 541-545 ◽  
Author(s):  
Jun Seong Park ◽  
Dae Hee Yun ◽  
Tae Won Ko ◽  
Yong Sung Park ◽  
Je Wan Woo
Keyword(s):  
Kinetic Study ◽  
Reaction Temperature ◽  
Atmospheric Pressure ◽  
Arrhenius Equation ◽  
Alder Reaction ◽  
Diels Alder ◽  
Influence Of Temperature ◽  
Diels Alder Reaction ◽  
Influence Of Temperature On ◽  
Kinetics Of

The kinetics of the Diels-Alder reaction of cyclopentadiene with bis(2-ethylhexyl) maleate has been studied at temperatures between 25 and 100 °C and at atmospheric pressure. The influence of temperature on the kinetic constants was determined by fitting the results to the Arrhenius equation. As a result, fitting line similar with the linear curve of the Arrhenius equation at 25, 30 and 40 °C. However, the fitting curve, at 60, 80 and 100 °C, tended towards the outside of the curve in the form of Arrhenius equation. The ratio of endo/exo was a slight change from increase of the reaction temperature.

Ferricyanide Oxidation of Butanol Homogeneously Catalysed by Chlororuthenium Complexes

1979 ◽  
Vol 32 (9) ◽  
pp. 1905 ◽  
Author(s):  
AF Godfrey ◽  
JK Beattie
Keyword(s):  
Aqueous Solution ◽  
Complex Formation ◽  
Linear Dependence ◽  
Rate Constants ◽  
Homogeneous Catalyst ◽  
Basic Solution ◽  
Rate Law ◽  
Kinetics Of ◽  
Solution Estimates ◽  
Butanol Concentration

The oxidation of butan-1-ol by ferricyanide ion in alkaline aqueous solution is catalysed by solutions of ruthenium trichloride hydrate. The kinetics of the reaction has been reinvestigated and the data are consistent with the rate law -d[FeIII]/dt = [Ru](2k1k2 [BuOH] [FeIII])/(2k1 [BuOH]+k2 [FeIII]) This rate law is interpreted by a mechanism involving oxidation of butanol by the catalyst (k1) followed by reoxidation of the catalyst by ferricyanide (k2). The non-linear dependence of the rate on the butanol concentration is ascribed to the rate-determining, butanol-independent reoxidation of the catalyst, rather than to the saturation of complex formation between butanol and the catalyst as previously claimed. Absolute values of the rate constants could not be determined, because some of the ruthenium precipitates from basic solution. With K3RuCl6 as the source of a homogeneous catalyst solution, estimates were obtained at 30�0�C of k1 = 191. mol-1 s-1 and k2 = 1�4 × 103 l. mol-1 s-1.

Photolysis of methylcobalamin in aqueous solution: A kinetic study

2018 ◽  
Vol 362 ◽  
pp. 40-48 ◽  
Author(s):  
Faiyaz H.M. Vaid ◽  
Saima Zahid ◽  
Ambreen Faiyaz ◽  
Kiran Qadeer ◽  
Wajiha Gul ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Kinetic Study

Kinetic study of hydrate formation for argon + TBAB + SDS aqueous solution system

2018 ◽  
Vol 116 ◽  
pp. 121-129 ◽  
Author(s):  
Saeideh Babaee ◽  
Hamed Hashemi ◽  
Amir H. Mohammadi ◽  
Paramespri Naidoo ◽  
Deresh Ramjugernath
Keyword(s):  
Aqueous Solution ◽  
Kinetic Study ◽  
Hydrate Formation ◽  
Solution System
Sign in / Sign up

Export Citation Format

Share Document