632-25-7Relevant articles and documents
Kinetics and Mechanism of the Reaction between Thymol Blue and Bromate in Acidic Medium
Jonnalagadda, S. B.,Chinake, C.,Simoyi, R. H.
, p. 1635 - 1640 (1995)
The reaction between Thymol Blue (TB) and bromate in the presence of sulfuric acid has been studied by monitoring the depletion kinetics of TB.The reaction exhibits complex kinetic behaviour.Under excess bromate and acid conditions, the reaction was initially fast and was followed by a kinetically controlled slow reaction.After an induction period, the reductant again underwent a rapid depletion.The kinetic data were analysed by determining the reaction rates under the two rapid depletion conditions and by estimating the induction time between the two rapid depletion stages.Under the initial conditions the rate-limiting step was found to be first order with respect to H(1+), bromate and TB.The overall potential of the reaction increased continuously with the progress of the reaction.The concentration of bromide dropped initially and built up slowly reaching a maximum before decreasing rapidly with corresponding fast depletion of Thymol Blue.At low bromate concentration TB reacted with bromate with stoichiometric ratio of 3:2, but with excess bromate the ratio increased to 4:5.The kinetics of the reaction between Thymol Blue and aqueous bromine were monitored by a stopped-flow technique.The probable reaction mechanism with bromide acting as an autocatalyst is discussed.
Correlation of the rates of Solvolysis of 2,1-benzoxathiol-3-one-1, 1-dioxide (2-sulfobenzoic acid cyclic anhydride)
Kevill, Dennis N.,Ryu, Zoon Ha
, p. 561 - 566 (2015/11/27)
Solvolysis of acyclic mixed carboxylic-sulfonic anhydrides in hydroxylic solvents is known to involve displacement at the carbonyl carbon to produce a carboxylic acid (water as the nucleophile) and/or an ester (alcohol as the nucleophile) plus the anion of the sulfonic acid. Parallel solvolyses of the cyclic mixed anhydride 2-sulfobenzoic anhydride (structurally similar to phthalic anhydride but with one carbonyl group replaced by a sulfonyl group) involve expulsion from the carbonyl carbon of a sulfonate anion that remains attached as an orthosubstituent in the benzoic acid and/or benzoate ester produced. This complicates the choice of a solvent-ionising-power scale for use in an extended Grunwald-Winstein equation treatment. The YOTs scale, previously recommended as a good general purpose scale, is chosen and used in conjunction with the NT solvent nucleophilicity scale. An acceptable correlation is obtained, which is improved when the two solvents rich in the highly ionising 1,1,1,3,3,3-hexafluoro-2-propanol are excluded. As the solvent is varied, the sensitivities to the changes induced in the two scales are low, consistent with an early transition state, but their ratio has a value which is typical for a pathway involving addition-elimination, with addition rate-determining. Earlier reports, supporting aspects of the proposed mechanism, are reviewed.
Synthesis of a few cyclothiadiazanones and aminosulfonyl benzamides from saccharin
Ramana, P. Venkata,Reddy, A. Ram
body text, p. 71 - 81 (2010/10/04)
Saccharin is hydrolyzed with two different acids to yield 1,2-di-acid. The di-acid, on chlorination with phosphorous pentachloride, gave 2-chlorosulfonylbenzoyl chloride. The 2-chlorosulfonylbenzoyl chloride on hydrazinolysis gave benzothiadiazinetrione, while with phenyl hydrazine it selectively yielded 2-phenylbenzothiadiazinetrione. 2-chlorosulfonoylbenzoyl chloride with different aromatic 1,2- diamines resulted in dibenzothiadiazocine derivatives. Electron-donating groups in the diamine facilitate while the electron-withdrawing groups retard the cyclization. However, aliphatic diamines, aniline and substituted anilines readily gave acyclic aminosulfonyl carboxybenzamides on condensation with 2- chlorosulfonylbenzoyl chloride. The di-acid and anhydride did not react with either hydrazine/phenyl hydrazine or amines to give the above products. However, when its ester derivative, isopropyl-2- chlorosulfonylbenzoate, condensed with hydrazine, it gave benzothiadiazinetrione. But the ester failed to react with phenyl hydrazine. All the condensation reactions were carried out at room temperature.
