scholarly journals Kinetics of macroradicals propagation and decay in polymeric matrix of 1,6-hexanediol diacrylate

2007 ◽  
Vol 1 (3) ◽  
pp. 161-164
Author(s):  
Yuriy Medvedevskikh ◽  
◽  
Galyna Khovanets’ ◽  
Andriy Kytsya ◽  
Iryna Yevchuk ◽  
...  
Keyword(s):  
Experimental Data ◽  
Reaction Kinetic ◽  
Order Reaction ◽  
Polymeric Matrix ◽  
Chain Propagation ◽  
Matrix Diffusion ◽  
Second Order Reaction ◽  
Chain Propagation Reaction ◽  
Kinetics Of ◽  
Bimolecular Mechanism

Dependence of acrylate macroradicals concentration in polymeric matrix of 1,6-hexanediol diacrylate on time within temperature range of 45-80С has been investigated by means of ESR-spectroscopy. It has been established that experimental data do not linearize in coordinates of equation of the second order reaction, what coordinates with bimolecular mechanism of macroradicals decay. It has been suggested, that the effect of decreasing of the rate constant of bimolecular macroradicals decay in time is related with their propagation in chain propagation reaction. Kinetic equation obtained on this basis satisfactorily describes experimental data, what allowed to estimate quantitatively such parameters as the rate constants of chain propagation an termination in polymeric matrix, diffusion coefficient of macroradicals and characteristic time of segmental movement.

scholarly journals DENITRIFICATION KINETICS OF PSEUDOMONAS STUTZERI AZ101

2019 ◽  
Vol 7 (7) ◽  
pp. 247-255
Author(s):  
Ahmad Idi
Keyword(s):  
Nitrogen Removal ◽  
Reaction Kinetic ◽  
Pseudomonas Stutzeri ◽  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
16S Rrna Analysis ◽  
Denitrification Kinetics ◽  
Aquaculture Wastewater ◽  
Kinetics Of

Nitrogen removal from environment is significant due to its effect on health and the whole ecosystems. Hence a highly nitrogen tolerant aerobic denitrifier, Pseudomonas stutzeri AZ101 was isolated from aquaculture wastewater and characterized using 16S rRNA analysis. The ability of the isolate to carry out simultaneously nitrification and denitrification (SND) was investigated. Different initial concentrations of nitrate and ammonium were used to determine the rate of SND. The denitrification data fitted well with the second order reaction kinetics with correlation coefficient between 0.923-0.9588. The nitrification data does not fit to both first and second order reaction kinetic but progressive shifts in the logarithm phase of the growth were observed at different initial concentrations. The kinetics data provide a significant insight to nitrogen removal from the wastewater.

Kinetic studies of the reactions between isocyanates and carboxylic acids

1994 ◽  
Vol 6 (3) ◽  
pp. 235-239 ◽  
Author(s):  
Hong Xiao ◽  
Han X Xiao ◽  
Kurt C Frisch ◽  
Nelson Malwitz
Keyword(s):  
Carboxylic Acids ◽  
Reaction Kinetic ◽  
Arrhenius Plot ◽  
Kinetic Studies ◽  
Isobutyric Acid ◽  
Phenyl Isocyanate ◽  
Order Reaction ◽  
Second Order Reaction ◽  
Different Temperatures ◽  
Kinetics Of

Reaction kinetic studies between isocyanates and carboxylic acids were undertaken to evaluate the kinetic parameters. Various isocyanates (phenyl isocyanate, cyclohexyl isocyanate) and carboxylic acids (acetic acid, n-butyric acid, isobutyric acid, dimethylbutyric acid and benzoic acid) were used to study the kinetics of the reactions at different temperatures and in different solvents. It was found that these reactions followed the rate law of second-order reaction. From the Arrhenius plot, the activation energies of these reactions were computed.

Kinetics of the reaction between hexamethylenediisocyanate and 1-pentanol

1983 ◽  
Vol 48 (11) ◽  
pp. 3279-3286
Author(s):  
Slavko Hudeček ◽  
Miloslav Bohdanecký ◽  
Ivana Hudečková ◽  
Pavel Špaček ◽  
Pavel Čefelín
Keyword(s):  
Liquid Chromatography ◽  
Rate Constants ◽  
Reversed Phase ◽  
Order Reaction ◽  
Second Order ◽  
Second Order Reaction ◽  
Reversed Phase Liquid Chromatography ◽  
Consecutive Reactions ◽  
Phase Liquid ◽  
Kinetics Of

The reaction between hexamethylenediisocyanate and 1-pentanol in toluene was studied by means of reversed-phase liquid chromatography. By employing this method, it was possible to determine all components of the reaction mixture including both products, i.e. N-(6-isocyanate hexyl)pentylcarbamate and N,N'-bis(pentyloxycarbonyl)hexamethylenediamine. Relations for the calculation of kinetic constants were derived assuming a competitive consecutive second-order reaction. It was demonstrated that the reaction involved in this case is indeed a second-order reaction, and the rate constants of the first and second consecutive reactions were determined.

scholarly journals SOLVATION OF THE [Cr(NCS)4(IMIDAZOLE)2] ION IN ETHANOL-WATER MIXTURES

2002 ◽  
Vol 10 (11) ◽  
pp. 63-72
Author(s):  
lon Ganescu ◽  
George Bratulescu ◽  
Ion Papa ◽  
Anca Ganescu ◽  
Alin Barbu ◽  
...  
Keyword(s):  
Kinetic Parameters ◽  
Order Reaction ◽  
Water Molecules ◽  
Hydrogen Ions ◽  
Second Order Reaction ◽  
Acidic Solutions ◽  
The Third ◽  
Competitive Reactions ◽  
Different Temperatures ◽  
Kinetics Of

Salvation kinetics of [Cr(NCS)4(imidazole)2]- has been studied in ethanol-water mixtures at different temperatures. The first stage of the solvation consists of two competitive reactions: two NCS- ions are exchanged, presumably, by water molecules and simultaneously an imidazole molecule by ethanol, the latter in a second-order reaction, accelerated by hydrogen ions. The exchange of the amine is followed by the substitution of the first two NCS- ions. The third and fourth NCS- ions are substituted only in neutral and slightly acidic solutions. Kinetic parameters have been determined for reactions (1), (2), and (4). The influence of the solvent composition and acidity is discussed

scholarly journals The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate

2000 ◽  
Vol 65 (12) ◽  
pp. 857-866
Author(s):  
Mladjen Micevic ◽  
Slobodan Petrovic
Keyword(s):  
Kinetic Data ◽  
Reaction Rate ◽  
Frequency Factor ◽  
Reaction Rate Constant ◽  
Order Reaction ◽  
Activation Entropy ◽  
Second Order Reaction ◽  
Third Order ◽  
First Order ◽  
Kinetics Of

The alcoholysis of 1,2,2-trimethylpropyl-methylfluorophosphonate (soman) was examined with a series of alkoxides and in corresponding alcohols: methanol, ethanol, 1-propanol, 2-propanol, 2-methoxyethanol and 2-ethoxyethanol. Soman reacts with the used alkoxides in a second order reaction, first order in each reactant. The kinetics of the reaction between 1,2,2-trimethylpropyl-methylfluorophosphonate and ethanol in the presence of diethylenetriamine was also examined. A third order reaction rate constant was calculated, first order in each reactant. The activation energy, frequency factor and activation entropy were determined on the basis of the kinetic data.

scholarly journals Translocation of Cations During Sorption of Copper in the System Solution - Algae (Spirogyra sp.)/Translokacja Kationów Podczas Procesu Sorpcji Miedzi W Układzie Roztwór - Glony (Spirogyra Sp.)

2014 ◽  
Vol 21 (3) ◽  
pp. 425-433
Author(s):  
Małgorzata Rajfur ◽  
Andrzej Kłos ◽  
Jan Kříž
Keyword(s):  
Order Reaction ◽  
Static System ◽  
Second Order Reaction ◽  
System Solution ◽  
Fixed Proportion ◽  
Pseudo Second Order ◽  
The Difference ◽  
Kinetics Of ◽  
Copper Cations ◽  
Solution Volume

Abstract Kinetics of the sorption of copper cations in Spirogyra sp. algae was analysed, together with the accompanying processes of hydrogen cations sorption and releasing to the solution the cations bonded in the algae: Na+, Mg2+, K+ and Ca2+. It was established that, in a static system, at the fixed proportion of algae mass to the solution volume, these processes occur simultaneously, however presumably the quantity of the released salts influences the parameters of heterophase equilibrium of ion exchange. In the experiment conditions, the quantity of the released cations was nearly 10 times larger than the quantity of the sorbed cations. The equilibrium parameters, determined from the model of pseudo second order reaction, were compared with the parameters obtained after 30 min of the process duration, ie at relatively stable indications of measuring equipment. On the example of the sorbed copper, the difference is approximately 8%. It was confirmed that the solution conductivity is a good parameter for the estimation of the state close to equilibrium.

Studies in the Vulcanization of Rubber. III—Kinetics of Vulcanization of Rubber with Sulfur and Selenium

1930 ◽  
Vol 3 (4) ◽  
pp. 650-659
Author(s):  
John T. Blake
Keyword(s):  
Molecular Weight ◽  
Order Reaction ◽  
Order Equation ◽  
Second Order Reaction ◽  
Experimental Conditions ◽  
Mathematical Basis ◽  
First Order ◽  
Kinetics Of ◽  
Kinetics Of Vulcanization

Abstract A procedure for the determination of combined selenium in rubber has been evolved. The rate of combination of selenium and rubber has been ascertained under certain conditions and shown to follow a first-order equation. A minimum value for the molecular weight of rubber has been estimated. The formation of hard rubber under chosen experimental conditions has been put on a mathematical basis and has been shown to follow a second-order reaction. The soft- and hard-rubber reactions have been shown qualitatively to be successive reactions and the function of accelerators has been discussed. The theory explains the anomalous results obtained by previous investigators.

Pseudo-Homogenous Kinetics Model for the Synthesis of Dimethyl Carbonate from Urea and Methanol with Heterogeneous Catalyst

2011 ◽  
Vol 233-235 ◽  
pp. 481-486
Author(s):  
Wen Bo Zhao ◽  
Ning Zhao ◽  
Fu Kui Xiao ◽  
Wei Wei
Keyword(s):  
Experimental Data ◽  
Activation Energy ◽  
Dimethyl Carbonate ◽  
Side Reaction ◽  
Order Reaction ◽  
Zero Order ◽  
Kinetics Model ◽  
First Order ◽  
Zero Order Reaction ◽  
Kinetics Of

The synthesis of dimethyl carbonate (DMC) from urea and methanol includes two main reactions: one amino of urea is substituted by methoxy to produce the intermediate methyl carbamate (MC) which further converts to DMC via reaction with methanol again. In a stainless steel autoclave, the kinetics of these reactions was separately investigated without catalyst and with Zn-containing catalyst. Without catalyst, for the first reaction, the reaction kinetics can be described as first order with respect to the concentrations of methanol and methyl carbamate (MC), respectively. For the second reaction, the results exhibit characteristics of zero-order reaction. Over Zn-containing catalyst, the first reaction is neglected in the kinetics model since its rate is much faster than second reaction. After the optimization of reaction condition, the macro-kinetic parameters of the second reaction are obtained by fitting the experimental data to a pseudo-homogenous model, in which a side reaction of DMC synthesis is incorporated since it decreases the yield of DMC drastically at high temperature. The activation energy of the reaction from MC to DMC is 104 KJ/mol while that of the side reaction of DMC is 135 KJ/mol.

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