- Kinetics of hydrolysis of aromatic mono- and disulfonyl chlorides
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A continuous polarografic method of recording instantaneous concentrations of - SO2Cl groups in an aqueous acetic acid system containing CH3CO2Na has been elaborated.Ten model monosulfonyl chlorides underwent hydrolysis according to pseudo-first order kinetics (20percent H2O, 80percent v.v.CH3CO2H, 0.5 mol/dm3 CH3CO2Na).Plots of hydrolysis for seven disulfonyl dichlorides with different number of - CH3 groups have been determined.Pseudo-first order rate constants for two consecutive reactions of hydrolysis (k1 and k2) have been computed and the influence of -SO2Cl and -SO3- groups on the reactivity of the second group - SO2Cl has been discussed.The mechanism of nucleophilic substitution has also been discussed.
- Sanecki, Przemyslaw,Rokaszewski, Edward
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p. 2263 - 2267
(2007/10/02)
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- Aromatic sulfonation 85. Halogen directing and steric effects in the sulfonation of the twelve halogenotoluenes and some related compounds
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The isomer distributions for the sulfonation of the twelve halogenotoluenes and some trisubstituted halogenomethylbenzenes, with both 98.4 percent H2SO4 at 25 deg C and sulfur trioxide in nitromethane at 0 deg C, have been determined and found to be very similar.The predominantly para-directing effect of the halogen substituent dominates over that of the methyl substituent: with the 2-halogenotoluenes, the degree of 5-substitution decreases from >/= 90 percent for the fluoro to 50 percent for the iodo compound.The 2- to 3-sulfonation ratio of the 4-halogenotoluenes strongly increases on going from fluorine (0.5) to iodine (7).The ratio of the partial rate factors for the sulfonation of a halogenobenzene ortho and meta to halogen varies from 17 +/- 1 for the fluoro to 1.5 +/- 0.4 for the iodo substituent.In competition to the sulfonation, 2- and 4-iodotoluene undergo deiodination, The latter process is more important with the 4-isomer and with the protic sulfonating reagent.With the aprotic reagent, the reaction proceeds by direct sulfodeiodination, whereas with the sulfuric acid reagent, it proceeds by initial protiodeiodination and sulfodeprotonation.
- Cerfontain, Hans,Koeberg-Telder, Ankie,Laali, Khosrow,Lambrechts, Hans J. A.,Wit, Peter de
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p. 390 - 392
(2007/10/02)
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