Kinetics of reaction of 1-chloro-2,4,6-trinitrobenzene with enolate ions of 2,4-pentanedione and methyl 3-oxobutanoate

1983 ◽  
Vol 48 (6) ◽  
pp. 1608-1617 ◽  
Author(s):  
Vladimír Macháček ◽  
Jaroslav Andrle ◽  
Vojeslav Štěrba
Keyword(s):  
Rate Constant ◽  
Dimethyl Sulphoxide ◽  
Mechanism Of Formation ◽  
Kinetics Of Reaction ◽  
Kinetics Of

Reaction of 1-chloro-2,4,6-trinitrobenzene (I) with anions of 2,4-pentanedione (II) and methyl 3-oxobutanoate (III) produces 3-(2,4,6-trinitrophenyl)-2,4-pentanedione (IV) and methyl 2-(2,4,6-trinitrophenyl)-3-oxobutanoate (V), respectively, besides 2,4,6-trinitrophenol (VI). Amount of 2,4,6-trinitrophenol decreases with increasing amount of dimethyl sulphoxide and 2,4-pentanedione in methanol. A mechanism of formation of 2,4,6-trinitrophenol is suggested. Rate constant of formation of 3-(2,4,6-trinitrophenyl)-2,4-pentanedione in methanol-dimethyl sulphoxide mixtures increases with increasing content of dimethyl sulphoxide and decreases with increasing LiCl concentration. In methanol, 1-chloro-2,4,6-trinitrobenzene reacts with anion of 2,4-pentanedione about 20x slower than with anion of methyl 3-oxobutanoate.

Mechanism of formation of Grignard reagents. Kinetics of reaction of alkyl halides in diethyl ether with magnesium

1980 ◽  
Vol 102 (1) ◽  
pp. 217-226 ◽  
Author(s):  
Harold R. Rogers ◽  
Craig L. Hill ◽  
Yuzo Fujiwara ◽  
Randall J. Rogers ◽  
H. Lee Mitchell ◽  
...  
Keyword(s):  
Diethyl Ether ◽  
Alkyl Halides ◽  
Grignard Reagents ◽  
Mechanism Of Formation ◽  
Kinetics Of Reaction ◽  
Kinetics Of

Effects of ortho-Substituents in Protonolysis of Arylmercuric Chlorides with Hydrochloric Acid

2000 ◽  
Vol 65 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Yulan Wang ◽  
Yangjie Wu
Keyword(s):  
Hydrochloric Acid ◽  
Rate Constant ◽  
Sodium Iodide ◽  
Underlying Mechanism ◽  
Experimental Results ◽  
Fixed Temperature ◽  
First Order ◽  
Kinetics Of Reaction ◽  
Kinetics Of

The kinetics of reaction of ortho-substituted phenylmercuric chlorides, 2-R-C6H4HgCl (R = H, CH3, CH3O, C2H5O, CF3, COOC2H5, Cl, Br, F, NO2), with hydrochloric acid in absolute ethanol in the presence of sodium iodide has been studied. The reaction is of the overall second order, first order with respect to each reactant. The rate constant determined at a fixed temperature decreases in the order of R: C2H5O > CH3O > CH3 > H > COOC2H5 > F > Cl > Br > CF3 > NO2. The role of inductive, resonance and field effects of the ortho-substituents, and the relation between steric demands of the ortho-substituents and volume of attacking species are discussed. The underlying mechanism is proposed on the basis of experimental results.

Kinetics of Substitution of 4-Methoxyphenylazo Groups of 2,6-Dioxo-5(3)-(4-methoxyphenylazo)-3(5)-(4-methoxyphenylhydrazono)-1,2,3,6-tetrahydropyridine-4-carboxylic Acid by Reaction with 4-Nitrobenzenediazonium Cation

1994 ◽  
Vol 59 (7) ◽  
pp. 1665-1672 ◽  
Author(s):  
Jaroslava Horáčková ◽  
Vojeslav Štěrba
Keyword(s):  
Carboxylic Acid ◽  
Rate Constant ◽  
Kinetics Of

Kinetics have been studied of gradual replacement of 4-methoxyphenylazo groups in 2,6-dioxo-5(3)-(4-methoxyphenylazo)-3(5)-(4-methoxyphenylhydrazono)-1,2,3,6-tetrahydropyridine-4-carboxylic acid (IIIa) by 4-nitrophenylazo groups using the reaction with 4-nitrobenzenediazonium cation (IIc) in acetate and phosphate buffers. The rate constant of replacement of the second methoxyphenylazo group is lower by a factor of ca 60. From the experimentally found pKa values of the corresponding azohydrazone compounds with methoxy, chloro, or nitro substituent at 4-position (IIIa - IIIf) it has been concluded that the 5(3)-(4-methoxyphenylazo)-3(5)-(4-nitrophenylhydrazono) derivative is formed in the first step.

scholarly journals Simultaneous Kinetics of Selenite Oxidation and Sorption on δ-MnO2 in Stirred-Flow Reactors

2021 ◽  
Vol 18 (6) ◽  
pp. 2902
Author(s):  
Zheyong Li ◽  
Yajun Yuan ◽  
Lin Ma ◽  
Yihui Zhang ◽  
Hongwei Jiang ◽  
...  
Keyword(s):  
Rate Constant ◽  
Photoelectron Spectroscopy ◽  
Oxide Surfaces ◽  
Kinetic Rate Constant ◽  
Flow Reactors ◽  
Mn Oxide ◽  
Remediation Strategies ◽  
Process Of Se ◽  
Kinetics Of

Selenium (Se) is an essential and crucial micronutrient for humans and animals, but excessive Se brings negativity and toxicity. The adsorption and oxidation of Se(IV) on Mn-oxide surfaces are important processes for understanding the geochemical fate of Se and developing engineered remediation strategies. In this study, the characterization of simultaneous adsorption, oxidation, and desorption of Se(IV) on δ-MnO2 mineral was carried out using stirred-flow reactors. About 9.5% to 25.3% of Se(IV) was oxidized to Se(VI) in the stirred-flow system in a continuous and slow process, with the kinetic rate constant k of 0.032 h−1, which was significantly higher than the apparent rate constant of 0.0014 h−1 obtained by the quasi-level kinetic fit of the batch method. The oxidation reaction was driven by proton concentration, and its rate also depended on the Se(IV) influent concentration, flow rate, and δ-MnO2 dosage. During the reaction of Se(IV) and δ-MnO2, Mn(II) was produced and adsorbed strongly on Mn oxide surfaces, which was evidenced by the total reflectance Fourier transform infrared (ATR-FTIR) results. The X-ray photoelectron spectroscopy (XPS) data indicated that the reaction of Se(VI) on δ-MnO2 produced Mn(III) as the main product. These results contribute to a deeper understanding of the interface chemical process of Se(IV) with δ-MnO2 in the environment.

scholarly journals Physical properties and water absorption kinetics of three varieties of Mucuna beans

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ajibola B. Oyedeji ◽  
Olajide P. Sobukola ◽  
Ezekiel Green ◽  
Oluwafemi A. Adebo
Keyword(s):  
Physical Properties ◽  
Water Absorption ◽  
Rate Constant ◽  
Geometric Mean ◽  
Seed Mass ◽  
Activation Energies ◽  
Mucuna Pruriens ◽  
Absorption Kinetics ◽  
Kinetics Of ◽  
Soaking Temperature

AbstractThe physical properties and water absorption kinetics of three varieties of Mucuna beans (Mucuna pruriens, Mucuna rajada and Mucuna veracruz) were determined in this study. Physical properties including length, width, thickness, geometric mean diameter, sphericity, porosity, bulk density, area, volume and one thousand seed mass were calculated while hydration kinetics was studied by soaking Mucuna beans in water at 30 °C, 40 °C and 50 °C and measuring water uptake at 9 h interval. Peleg’s equation was used to model the hydration characteristics and Arrhenius equation was used to describe the effect of temperature on Peleg’s rate constant k1 and to obtain the activation energies for soaking. Significant variations were observed in almost all the physical properties of the different varieties, however, there were no significant differences (p < 0.05) in their thicknesses and bulk densities. The effectiveness of fit of Peleg’s model (R2) increased with increase in soaking temperature. Peleg’s rate constant k1 decreased with increase in soaking temperature while k2 increased with temperature increase. Activation energies of Mucuna pruriens, Mucuna rajada and Mucuna veracruz were 1613.24 kJ/mol, 747.95 kJ/mol and 2743.64 kJ/mol, respectively. This study provides useful information about the properties of three varieties of Mucuna beans that could be of importance to processors and engineers for process design and optimization.

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