46506-54-1Relevant academic research and scientific papers
Sulfonation and sulfation in reactions of C-methylated phenols and anisoles with sulfur trioxide. 4-Substituted phenyl hydrogen sulfates: effective reagents for transsulfonation
Goossens, Hans D.,Lambrechts, Hans J. A.,Cerfontain, Hans,Wit, Peter de
, p. 426 - 430 (2007/10/02)
The sulfation and sulfonation of the methyl- and dimethylphenols with 0.9 and 4.0 equiv. of SO3 in nitromethane at 0 deg C have been studied.On using 0.9 equiv. of SO3, the sulfonic acid product distributions are determined by the ortho- and para-directing effect of the activating hydroxy substituent.In the reactions with 4.0 equiv. of SO3, the sulfonic acid product distributions are affected by the predominant initial formation and the subsequent sulfonation of the corresponding phenyl hydrogen sulfates, of which the bulky OSO3H substituent is electronically deactivating and (mainly) para-directing.For comparison, the sulfonation of the methylanisoles, phenyl methanesulfonate and 2,3-dihydrobenzofuran was also studied.The sulfonation of 1,3-dimethoxybenzene in (2H8)dioxane at 17.0 deg C has been studied using 4-substituted phenyl hydrogen sulfates as transsulfonating agents.The transsulfonation was found to be first order with respect to the phenyl hydrogen sulfates and independent of the 1,3-dimethoxybenzene concentration.The reaction constant of the transsulfonation reaction was determined to be ρ=2.0+/-0.2.
Aromatic Sulfonation. Part 94. Sulphonation and Sulphation of the Three 2- and 4-Hydroxy- and 2- and 4-Methoxy-benzenesulphonic Acids in Concentrated Sulphuric Acid
Koeberg-Telder, Ankie,Lambrechts, Hans J. A.,Cerfontain, Hans
, p. 1241 - 1246 (2007/10/02)
The sulphonation of 2-methoxy- (1) and 4-methoxy-benzene sulphonate (2) and 1- (3), 3- (4), and 4-hydroxybenzenesulphonate (5) in 86.9-98.5percent H2SO4 at 25 deg C has been studied.Substrates (1)-(3) and (5) all yield the corresponding 2,4-disulphonic acid as the exclusive product, whereas (4) yields a mixture of 2-hydroxybenzene-1,4- and 4-hydroxybenzene-1,2disulphonic acid. 3- and 4-Hydroxy-benzenesulphonic acids in sulphuric acid (>87percent H2SO4) are present in part as their hydrogen sulphates and the sulphuric acid concentration of 50percent sulphation is 97.5 and 100.5 +/- 0.2percent H2SO4.The sulphonation is first order in the aromatic substrate.From the rate dependence on the sulphuric acid concentration it is concluded that the substrate species undergoing ring sulphonation is the -O3SC6H4OR (R = H; Me) species with H2S2O7 as the sulphonating entity.From the observed proportionality between -O3SC6H4OSO3H>/-O3SC6H4OH> and aSO3 it is concluded that the aromatic species undergoing sulphation is again -O3SC6H4OH.
Aromatic Sulphonation. Part 91. The Sulphonation of Anisole, Phenol, Phenyl Methanesulphonate, Potassium Phenyl Sulphate, and a Series of Methyl-, Bromo-, and Chloro-substituted Anisoles and Phenols in Concentrated Aqueous Sulphuric Acid
Cerfontain, Hans,Lambrechts, Hans J. A.,Schaasberg-Nienhuis, Zwaan R. H.,Coombes, Robert G.,Hadjigeorgiou, Panicos,Tucker, Geoffrey
, p. 659 - 668 (2007/10/02)
The (homogeneous) sulphonation of a number of aromatic ethers and alcohols, viz. anisole (1), 3-methyl- (2), 4-methyl- (3), 2-bromo- (4), 4-bromo- (5), 2-chloro- (6), and 4-chloro-anisole (7), phenol (8), 2-methyl- (9), 3-methyl- (10), 4-methyl- (11), 4-bromo- (12), 2-chloro- (13), and 4-chloro-phenol (14), phenyl methanesulphonate (15), and potassium phenyl sulphate (16) in concentrated aqueous sulphuric acid at 25.0 deg C has been studied, and rates and isomer distributions have been determined.The sulphonation is first-order in the aromatic substrate, and from the rate measurements it is concluded that the species undergoing sulphonation in the phenyl ring is an unprotonated substrate species.In the lower acid concentrations the sulphonating entity is H3SO4(1+).With increasing sulphuric acid concentration there is a gradual change-over in the sulphonating entity from H3SO4(1+) to H2S2O7.The acid concentrations of equal rate contribution by the two entities for anisole and phenol are 87 and 90 +/- 1percent, respectively.Sulphonation on the oxygen atom (i.e., sulphation) does not occur.The o/p-ratios for (1) and (8) do not vary over the studied sulphuric acid range of 75-90percent H2SO4.Partial rate factors for the 2- and 4-position of (1) and (8) are reported.The very low partial rate factors for the 4-substitution of (1) and (8) and the observed extreme suppression and compression of the reactivities of the substrates (1)-(14) are ascribed to hydrogen bonding of the substrates with the acidic solvent species present.It is tentatively suggested that the relatively high contents of sulphonation ortho to -OR with anisole (36percent) and phenol (48percent) are due to specific complexation of the substrates with the sulphonating electrophile.
