Electrophilic aromatic substitution. Part IX. The kinetics of nitration of benzene and some methylbenzenes in aqueous acetic acid and in acetic anhydride, with observations on limiting rates of nitration and on M.O.-theoretical treatments of nitration rates

1971 ◽  
pp. 2447 ◽  
Author(s):  
S. R. Hartshorn ◽  
R. B. Moodie ◽  
K. Schofield ◽  
M. J. Thompson
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Electrophilic Aromatic Substitution ◽  
Aqueous Acetic Acid ◽  
Aromatic Substitution ◽  
Kinetics Of

Kinetics and Mechanism of Oxidation of Dimethyl Sulphoxide by Mono- and Di-Substituted N,N-Dichlorobenzenesulphonamides in Aqueous Acetic Acid

2003 ◽  
Vol 58 (8) ◽  
pp. 787-794 ◽  
Author(s):  
B.Thimme Gowda ◽  
K. L. Jayalakshmi ◽  
K. Jyothi
Keyword(s):  
Acetic Acid ◽  
Benzene Ring ◽  
Dimethyl Sulphoxide ◽  
Aqueous Acetic Acid ◽  
Isokinetic Temperature ◽  
Free Energies ◽  
Kinetics Of Oxidation ◽  
First Order ◽  
First Order Kinetics ◽  
Kinetics Of

In an effort to introduce N,N-dichloroarylsulphonamides of different oxidising strengths, four mono- and five di-substituted N,N-dichlorobenzenesulphonamides are prepared, characterised and employed as oxidants for studying the kinetics of oxidation of dimethyl sulphoxide (DMSO) in 50% aqueous acetic acid. The reactions show first order kinetics in [oxidant], fractional to first order in [DMSO] and nearly zero order in [H+]. Increase in ionic strength of the medium slightly increases the rates, while decrease in dielectric constant of the medium decreases the rates. The results along with those of the oxidation of DMSO by N,N-dichlorobenzenesulphonamide and N,N-dichloro-4- methylbenzenesulphonamide have been analysed. Effective oxidising species of the oxidants employed in the present oxidations is Cl+ in different forms, released from the oxidants. Therefore the introduction of different substituent groups into the benzene ring of the oxidant is expected to affect the ability of the reagent to release Cl+ and hence its capacity to oxidise the substrate. Significant changes in the kinetic and thermodynamic data are observed in the present investigations with change of substituent in the benzene ring. The electron releasing groups such as CH3 inhibit the ease with which Cl+ is released from the oxidant, while electron-withdrawing groups such as Cl enhance this ability. The Hammett equation, log kobs = −3.19 + 1.05 σ , is found to be valid for oxidations by all the p-substituted N,N-dichlorobenzenesulphonamides. The substituent effect on the energy of activation, Ea and log A for the oxidations is also analysed. The enthalpies and free energies of activation correlate with an isokinetic temperature of 320 K.

Synthesis of 5,6-Diaryl-1,2,4-triazines

1978 ◽  
Vol 33 (12) ◽  
pp. 1503-1507 ◽  
Author(s):  
Farid S. G. Soliman ◽  
Ibrahim M. Labouta ◽  
A. Ibrahim El Sebai ◽  
S. A. Shams El Dine
Keyword(s):  
Acetic Acid ◽  
Acetic Anhydride ◽  
Sodium Carbonate ◽  
Sodium Carbonate Solution ◽  
Carbonate Solution ◽  
Aqueous Acetic Acid ◽  
Semicarbazide Hydrochloride

AbstractThe synthesis of 6-(4-methoxyphenyl)-5-phenyl-3-oxo-2,3-dihydro-1,2,4-triazine (5a) from 4-methoxybenzoin, 4-methoxybenzil, or 4-methoxybenzoin semicarbazone and semi-carbazide hydrochloride is reported. The condensation of 4-methoxybenzil with thiosemi-carbazide yielded 6-(4-methoxyphenyl)-5-phenyl-3-thioxo-2,3-dihydro-I,2,4-triazine (5b) which was converted to its 3-oxo analogue 5 a with acetic anhydride. Reduction of 5 a and 5 b with zinc and aqueous acetic acid led to the corresponding 2,3,4,5-tetrahydro-1,2,4-triazines 6 a and 6b, respectively. Oxidation of 5 b with iodine in sodium carbonate solution afforded bis [6-(4-methoxyphenyl)-5-phenyl-1,2,4-triazin-3-yl]disulphide (7). Analogous triazines were prepared by condensing 3,3'-diiodobenzil with semicarbazide hydrochloride or thiosemicarbazide.

scholarly journals Kinetics of Oxidation of Some Amino Acids by N-Chlorosaccharin in Aqueous Acetic Acid Medium

2004 ◽  
Vol 1 (2) ◽  
pp. 127-131 ◽  
Author(s):  
N. A. Mohamed Farook ◽  
R. Prabaharan ◽  
S. Rahini ◽  
R. Senthil Kumar ◽  
G. Rajamahendran ◽  
...  
Keyword(s):  
Amino Acids ◽  
Acetic Acid ◽  
Acid Medium ◽  
Hypochlorous Acid ◽  
Activation Parameters ◽  
Slow Step ◽  
Aqueous Acetic Acid ◽  
Acetic Acid Medium ◽  
Kinetics Of Oxidation ◽  
Kinetics Of

The kinetics of oxidation of some amino acids namely, glycine, alanine, aspartic acid, arginine, and histidine, (AA) byN-chlorosaccharin (NCSA) in aqueous acetic acid medium in the presence of perchloric acid have been investigated. The observed rate of oxidation is first order in [AA], [NCSA] and of inverse fractional order in [H+]. The main product of the oxidation is the corresponding aldehyde. The ionic strength on the reaction rate has no significant effect. The effect of changing the dielectric constant of the medium on the rate indicates the reaction to be of dipole-dipole type. Hypochlorous acid has been postulated as the reactive oxidizing species. The reaction constants involved in the mechanism are derived. The activation parameters are computed with respect to slow step of the mechanism.

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