Oxidative cyclizations. III. Kinetic studies of the oxidation of 2,4-dinitroaniline and 2-benzoylaniline with (diacetoxyiodo)benzene

1973 ◽  
Vol 26 (9) ◽  
pp. 1969 ◽  
Author(s):  
LK Dyall ◽  
JE Kemp
Keyword(s):  
Acetic Acid ◽  
Equilibrium Constants ◽  
Kinetic Studies ◽  
Reaction Rates ◽  
Oxidative Cyclization ◽  
Toluene Solution ◽  
Common Mechanism ◽  
Substituted Anilines ◽  
Oxidative Cyclizations ◽  
Cyclic Product

For the oxidative cyclization of 2,4-dinitroaniline and 2- benzoylaniline with (diacetoxyiodo)benzene in toluene solution, the kinetic orders are unity in amine and oxidant, zero in iodobenzene and cyclic product, and -1 in monomeric acetic acid. These characteristic orders are also those observed for 2-nitroaniline and, together with evidence for a specific solvation effect by acetic acid on the reaction rates of all three amines, indicate that a common mechanism of oxidative cyclization applies to a range of ortho-substituted anilines. For 2-benzoylaniline, there is infrared evidence of an N-H bond in an iodoso intermediate. ��� Equilibrium constants for the monomer ↔ dimer equilibrium of acetic acid in toluene solution have been determined at four temperatures between 25� and 46�.

Oxidative cyclizations. II. Kinetic studies of the reaction of 2-nitroaniline with phenyliodoso acetate in toluene solution

1968 ◽  
Vol 21 (2) ◽  
pp. 409 ◽  
Author(s):  
LK Dyall ◽  
JOM Evans ◽  
JE Kemp
Keyword(s):  
Acetic Acid ◽  
Kinetic Study ◽  
Oxidation Rate ◽  
Kinetic Studies ◽  
Toluene Solution ◽  
Mass Action ◽  
Action Effect ◽  
First Order ◽  
Oxidative Cyclizations ◽  
Two Stages

A kinetic study of the oxidation of 2-nitroaniline by phenyliodoso acetate in toluene solution reveals that the reaction is first order in both amine and oxidant. The mass action effects of products on oxidation rate demonstrate that at least two stages are involved in the reaction, and that the mass action effect of acetic acid is exerted only by its monomer. Evidence is obtained for the formation of an intermediate containing trivalent iodine. All these facts are consistent with the mechanism previously proposed by us for this reaction.

Oxidative cyclizations. IV. Isokinetic relationship in the oxidation of orthosubstituted anilines with (diacetoxyiodo)benzene

1973 ◽  
Vol 26 (12) ◽  
pp. 2665 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Acetic Acid ◽  
Reaction Mechanism ◽  
Acid Solution ◽  
Acetic Acid Solution ◽  
Activation Parameters ◽  
Oxidative Cyclization ◽  
Substituted Anilines ◽  
Isokinetic Relationship ◽  
Oxidative Cyclizations

The rates of oxidative cyclization of 11 ortho-substituted anilines by (diacetoxyiodo)benzene have been measured in toluene-acetic acid solution. The activation parameters give a precise fit to an isokinetic relationship, which indicates that a common reaction mechanism is followed. This mechanism applies to amines from the benzene, naphthalene, and anthraquinone families, with nitro and various carbonyl and arylazo groups as the ortho substituents.

Oxidative cyclizations. VII. Cyclization of 2-substituted anilines with alkaline hypohalite

1984 ◽  
Vol 37 (10) ◽  
pp. 2013 ◽  
Author(s):  
LK Dyall
Keyword(s):  
Oxidative Cyclization ◽  
Azo Compounds ◽  
Substituted Anilines ◽  
Oxidative Cyclizations ◽  
Visible Spectra ◽  
Transient Intermediates ◽  
Ortho Substituent

The Green-Rowe oxidation of 2-nitroanilines with alkaline hypochlorite, to yield benzofuroxans, is demonstrated by studies of the visible spectra of transient intermediates to proceed through N-chlorination and a singlet nitrene. Two variations on the route to the nitrene are possible. The cyclization step is represented as an internal capture of the nitrene by the ortho substituent, and on this basis the Green-Rowe oxidative cyclization is now extended to anilines whose ortho substituent is benzoyl or phenylazo. It is not however successful for ortho phenyl. Azo compounds were observed as byproducts in some of these reactions, and are shown to arise via N,N-dichloroanilines.

scholarly journals Understanding the reaction mechanism of the regioselective piperidinolysis of aryl 1-(2,4-dinitronaphthyl) ethers in DMSO: Kinetic and DFT studies

2021 ◽  
Vol 46 ◽  
pp. 146867832110274
Author(s):  
Yasmen M Moghazy ◽  
Nagwa MM Hamada ◽  
Magda F Fathalla ◽  
Yasser R Elmarassi ◽  
Ezzat A Hamed ◽  
...  
Keyword(s):  
Carbon Atom ◽  
Density Functional ◽  
Function Analysis ◽  
Density Functional Theory Method ◽  
Activation Parameters ◽  
Kinetic Studies ◽  
Nucleophilic Attack ◽  
Common Mechanism ◽  
Slow Step ◽  
Rate Determining Step

Reactions of aryl 1-(2,4-dinitronaphthyl) ethers with piperidine in dimethyl sulfoxide at 25oC resulted in substitution of the aryloxy group at the ipso carbon atom. The reaction was measured spectrophotochemically and the kinetic studies suggested that the titled reaction is accurately third order. The mechanism is began by fast nucleophilic attack of piperidine on C1 to form zwitterion intermediate (I) followed by deprotonation of zwitterion intermediate (I) to the Meisenheimer ion (II) in a slow step, that is, SB catalysis. The regular variation of activation parameters suggested that the reaction proceeded through a common mechanism. The Hammett equation using reaction constant σo values and Brønsted coefficient value showed that the reaction is poorly dependent on aryloxy substituent and the reaction was significantly associative and Meisenheimer intermediate-like. The mechanism of piperidinolysis has been theoretically investigated using density functional theory method using B3LYP/6-311G(d,p) computational level. The combination between experimental and computational studies predicts what mechanism is followed either through uncatalyzed or catalyzed reaction pathways, that is, SB and SB-GA. The global parameters of the reactants, the proposed activated complexes, and the local Fukui function analysis explained that C1 carbon atom is the most electrophilic center of ether. Also, kinetics and theoretical calculation of activation energies indicated that the mechanism of the piperidinolysis passed through a two-step mechanism and the proton transfer process was the rate determining step.

scholarly journals Perborate Oxidation of Substituted 5-Oxoacids in Aqueous Acetic Acid Medium: A Kinetic and Mechanistic Study

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
S. Shree Devi ◽  
B. Muthukumaran ◽  
P. Krishnamoorthy
Keyword(s):  
Acetic Acid ◽  
Acid Medium ◽  
Reaction Rate ◽  
Reaction Medium ◽  
Activation Parameters ◽  
Reaction Rates ◽  
Mechanistic Study ◽  
Aqueous Acetic Acid ◽  
Sodium Perborate ◽  
Acetic Acid Medium

Kinetics and mechanism of oxidation of substituted 5-oxoacids by sodium perborate in aqueous acetic acid medium have been studied. The reaction exhibits first order both in [perborate] and [5-oxoacid] and second order in [H+]. Variation in ionic strength has no effect on the reaction rate, while the reaction rates are enhanced on lowering the dielectric constant of the reaction medium. Electron releasing substituents in the aromatic ring accelerate the reaction rate and electron withdrawing substituents retard the reaction. The order of reactivity among the studied 5-oxoacids is p-methoxy ≫ p-methyl > p-phenyl > –H > p-chloro > p-bromo > m-nitro. The oxidation is faster than H2O2 oxidation. The formation of H2BO3+ is the reactive species of perborate in the acid medium. Activation parameters have been evaluated using Arrhenius and Eyring’s plots. A mechanism consistent with the observed kinetic data has been proposed and discussed. Based on the mechanism a suitable rate law is derived.

scholarly journals A Study on the Kinetics and Mechanism of the One-Pot Formation of 3,4,5-Substituted Furan-2(5H)-Ones in the Presence of Lactic Acid: Effect of Different Substituents

2018 ◽  
Vol 43 (3-4) ◽  
pp. 286-299 ◽  
Author(s):  
Osman Asheri ◽  
Sayyed Mostafa Habibi-Khorassani ◽  
Mehdi Shahraki
Keyword(s):  
Lactic Acid ◽  
Activation Parameters ◽  
General Mechanism ◽  
Common Mechanism ◽  
Substituted Anilines ◽  
One Pot ◽  
Isokinetic Relationship ◽  
Zero Order Kinetics ◽  
Different Temperatures ◽  
The One

The kinetics of the reaction between para-substituted anilines and dimethyl acetylenedicarboxylate (DMAD) with derivatives of benzaldehyde for the one-pot formation of 3,4,5-substituted furan-2(5 H)-ones in the presence of lactic acid as a catalyst have been studied spectrophotometrically at different temperatures. A mechanism involving four steps was proposed for the reactions, all of which followed second-order kinetics. The partial orders with respect to substituted aniline and DMAD were one and one and the reactions revealed zero-order kinetics for benzaldehyde and its derivatives. Changing of substituents on benzaldehyde left rates of reaction unaffected. However, various substituents on aniline showed that para electron-withdrawing groups decreased the rate of reaction. According to investigation of an isokinetic relationship, a common mechanism exists for all studied substituents and a general mechanism can be formulated. Kinetic values ( k and Ea) and associated activation parameters (Δ G‡, Δ S‡ and Δ H‡) of the reactions were determined.

scholarly journals Comparative Extraction of Aluminum Group Metals Using Acetic Acid Derivatives with Three Different-Sized Frameworks for Coordination

Separations ◽  
2021 ◽  
Vol 8 (11) ◽  
pp. 211
Author(s):  
Keisuke Ohto ◽  
Nako Fuchiwaki ◽  
Hiroaki Furugou ◽  
Shintaro Morisada ◽  
Hidetaka Kawakita ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Metal Ions ◽  
Spectroscopic Data ◽  
Equilibrium Constants ◽  
Structural Effects ◽  
Extraction Equilibrium ◽  
Ph Values ◽  
Slope Analysis ◽  
Coordination Sites ◽  
Extraction Properties

We prepared acetic acid derivatives using three different frameworks, calix[4]arene, alkenyltrimethylol, and trihydroxytriphenylmethane, which differ in the number and size of their coordination sites. We further investigated the extraction properties for aluminum group metal ions. All three extraction reagents exhibited increased extraction compared with the corresponding monomeric compounds, owing to structural effects. The extraction reaction and extraction equilibrium constants were determined using a slope analysis. Their extraction abilities, separation efficiencies, and potential coordination modes are discussed using the extraction equilibrium constants, half-pH values, and spectroscopic data. The calix[4]arene and trihydroxytriphenylmethane derivatives demonstrated allosteric co-extraction of indium ions (In3+) with an unexpected stoichiometry of 1:2.

scholarly journals Synthesis of Mn(II)-containing paratungstate B from aqueous solutions acidified by acetic acid

2021 ◽  
pp. 39-48
Keyword(s):  
Thermal Analysis ◽  
Acetic Acid ◽  
Aqueous Solutions ◽  
Equilibrium Constants ◽  
Background Electrolyte ◽  
Equilibrium Processes ◽  
Transformation Processes ◽  
Paratungstate B ◽  
Solution Acidity ◽  
Tungstate Anion

The method of pH-potentiometric titration and mathematical simulation were used to study the equilibrium processes in aqueous solutions of the WO42––CH3COOH–H2O system in the acidity range Z=(CH3COOH)/(Na2WO4)=0.8–1.7 at СW=0.01 mol L–1 and T=2980.1 K, a constant ionic strength being maintained by sodium nitrate as a background electrolyte ((NaNO3)=0.10 mol L–1). We developed the models of polyoxotungstate anions formation and the equilibrium transformation processes, which adequately describe experimental pH vs. Z dependences. It was found that acetic acid using to create the solution acidity that is necessary for the formation of isopoly tungstate anion contributes only to the formation of protonated paratungstate B anions Нх[W12O40(ОН)2](10–х)– (where x=0–4). We calculated the logarithms of the concentration equilibrium constants of the polyanion formation and plotted the distribution diagrams. Double sodium-manganese(II) paratungstate B Na8(H2O)28Mn(H2O)2[H2W12O42]4H2O was synthesized at Z=1.00 to confirm the results of the mathematical modeling. The chemical composition of the prepared salt was established by chemical elemental analysis, thermal analysis, FTIR spectroscopy, and single crystal X-ray analysis. The stepwise process of salt dehydration was studied by means of differential thermal analysis.

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