46060-27-9Relevant articles and documents
Structure-reactivity correlations in the dissociative hydrolysis of 2′,4′-dinitrophenyl 4-hydroxy-X-benzenesulfonates
Cevasco, Giorgio,Thea, Sergio
, p. 6814 - 6817 (2007/10/03)
The hydrolysis reactions of several title esters in water at 60°C follow the rate law kobs = (ka + kb[OH-])/(1 + αH/Ka), where Ka is the ionization constant of the hydroxy group of the ester and kb is the second-order rate constant for the SN2(S) attack of hydroxide ion on the ionized ester. Hammett and Br?nsted correlations are consistent with a previous proposal that the mechanism related to ka is dissociative. An unusual relationship between ka values and redox equilibrium constants for substituted quinones is found to hold: this finding further supports the dissociative nature of the pathway related to ka.
Sulfonation of chloro- and dichloroanisoles with concentrated aqueous sulfuric acid and sulfur trioxide. Demethylation of chloroanisolesulfonic acids in sulfuric acid systems
Wit, Peter de,Cerfontain, Hans
, p. 418 - 425 (2007/10/02)
The nine chloro- and dichloroanisoles have been sulfonated with sulfuric acid.The observed sulfonic acid isomer distributions are determined mainly by the ortho- and para-directing effect of the methoxy substituent.In the reaction with sulfuric acid, the initially formed chloro- and dichloroanisolesulfonic acids are demethylated to give the corresponding phenolsulfonic acids.Demethylation occurs only in those cases where the methoxy substituent is sterically hindered by an o-chloro and/or o-sulfo substituent.Reaction of 2,3- and 3,5-dichloroanisole with fuming sulfuric acid yields initially the 4,6- and 2,4-disulfonic acids, respectively.The disulfonic acids are converted to the corresponding hydrogen sulfates either by direct sulfodemethylation or by protodemethylation followed by subsequent sulfation.The 2,3-dichloro-4,6-disulfophenyl hydrogen sulfate cyclizes to the 1,3,2,4-benzodioxadithiin 2,2,4,4-tetraoxide 4.The sulfonation of the chloro- and dichloroanisoles with SO3 in the solvents nitromethane or CCl3F leads only to sulfodeprotonation.
On the intermediacy of phenyl hydrogen sulfates in the sulfonation of phenols. Sulfonation of phenol, anisole, methyl phenyl sulfate, the 2-halogenophenols, a series of phenyl methanesulfonates together with 2,6-dimethylaniline and its N-methylsulfonyl derivative
de Wit, Peter,Woldhuis, Alex F.,Cerfontain, Hans
, p. 668 - 675 (2007/10/02)
The sulfonation of methyl phenyl sulfate (4) with concentrated aqueous sulfuric acid at 25 deg C yields the 4-sulfonic acid.This initial product then decomposes to give phenol-4-sulfonic acid, which is subsequently sulfonated to phenol-2,4-disulfonic acid.From the first-order-rate coefficients obtained for sulfonation of phenyl methanesulfonate (3) and (4) in 93,2percent H2SO4, for which acid concentration the sulfonating entity is H2S2O7, the ?p+ values of the OSO2Me and OSO2OMe substituents have been determined to be 0.40 and 0.46, respectively.The sulfonation of both 2-chlorophenyl (10) and 2-methylphenyl methanesulfonate (14) with 2.0 equiv of SO3 in nitromethane at 0.0 deg C yields the 4-sulfonic acid as the exclusive product, whereas 2-methoxyphenyl methanesulfonate (13), under the same conditions, forms exclusively the 5-sulfonic acid. 2-Chloro- (6), 2-bromo- (7) and 2-iodophenol (8) with 1.0 and 4.0 equiv of SO3 in nitromethane yield exclusively the 4-sulfonic acid, while 2-fluorophenol (5) with 2.0 and 5.0 equiv of SO3 yields in addition the 5-sulfonic acid to the extent of 4 and 30percent, respectively.In the reactions of 2,6-dimethylphenol (15) and 2,6-dimethylaniline (17) with at least 1 equiv of SO3 in nitromethane, the 3-SO3H/4-SO3H ratio was found to increase on increasing the relative amount of SO3.For both 15 and 17, the limiting 3-SO3H/4-SO3H ratio at high SO3/ArOH ratios is 86/14 and this value is considered to be the ratio for the sulfonation of both 2,6-dimethylphenyl hydrogen sulfate and 2,6-dimethylaniline-N-sulfonic acid.This assumption is supported by the observation that the sulfonation of 2,6-dimethylphenyl methanesulfonate (16) and N-(methylsulfonyl)-2,6-dimethylaniline (18) with SO3 leads to a similar 3-SO3H/4-SO3H ratio.
