Benzenesulfonic acid reagent

It has been found that triamcinolone [101] and the 21-phosphate esters [102] do not under go the Porter-Silber reaction. It was also shown that an increased sensitivity for this procedure can be obtained using the p-hydrazino-benzenesulfonic acid-phosphoric acid reagent [103],... 

Maximum reaction rate is attainable with the strongest reagent, namely, SO3, and its use is increasing. As a consequence of the increased production of sulfonates, there is a compelling interest in more efficient and more rapid and especially continuous processes. The use of SO is subject to limitations, however, as noted in Table 7-3. It reacts virtually instantaneously with many compounds, for example, hydrocarbons or alcohols, even at low temperatures. In other cases, however, it first forms a complex with the compound being sulfonated, and rearrangement to the desired sulfonic acid requires time and heat, as with benzoic acid, benzenesulfonic acid, and pyridine. 

Because it is aromatic, benzene does not react directly with reagents such as HBr or HCl, or even with diatomic bromine or chlorine. Benzene reacts with cationic species to ve a resonance-stabilized carbocation intermediate, which loses a hydrogen to give a substitution product. This reaction is called electrophilic aromatic substitution. The most common method for generating reactive cations in the presence of benzene is to treat certain reagents with strong Lewis acids. Lewis acids or mixtures of strong acids can be used to convert benzene to chlorobenzene, bromobenzene, nitrobenzene, or benzenesulfonic acid. 

Use of 2,6-Dinitro-4-trifluoromethyl-benzenesulfonic Acid as a Novel Derivatizing Reagent for the Analysis of Catecholamines, Histamines and Related Amines by Gas Chromatography with Electron Capture Detection... 

Benzene (Table I, p. 165). Some of the factors involved in the industrial sulfonation of benzene have been discussed. In the small-scale, laboratory preparation, where the difference in cost between sulfuric acid and oleum is negligible, oleum is the preferred reagent. Benzene is added gradually to ice-cold sulfuric acid containing 5-8% of the anhydride the reaction is complete after ten to fifteen minutes. Benzensul-fonic acid is isolated readily as the sodium salt by the addition of the reaction mixture to a saturated sodium chloride solution. The reaction of benzene with chlorosulfonic acid is not used for the preparation of benzenesulfonic acid because, under conditions that limit the formation of the sulfonyl chloride, the acid is always accompanied by phenyl sulfone. Benzenesulfonyl chloride can be obtained in a yield of 75-77% by the addition of benzene to an excess of chlorosulfonic acid (room temperature). Fluorosulfonic acid reacts less vigorously the addi-... 

S)-N,N-Diethyl-p-toluenesulfinamide allowed to react with allyl alcohol in the presence of benzenesulfonic acid (-)-(S)-allyl p-toluenesulfinate. Y 95% inversion 92%. F. e. and reagents s. M. Mikolajczyk, J. Drabowicz, and B. Bujnicki, Chem. Commun. 1976, 568. 

Bassin, Cremlyn and Swinboume. Details of kinetic and mechanistic studies on sulfonation and chlorosulfonation of aromatic hydrocarbons and other derivatives have been described in Chapter 2. Chlorosulfonic acid is a very active sulfonating agent and when benzene is added to an excess of the reagent at room temperature, benzenesulfonyl chloride is formed (> 70%) with only a trace of diphenyl sulfone. " On the other hand, when an excess of benzene is present, the major products are diphenyl sulfone and benzenesulfonic acid. " ... 

Diphenyl sulfide 210 by reaction with an equimolar quantity of chlorosulfonic acid afforded 4-(phenylthio) benzenesulfonic acid 211, while the use of an excess of the reagent gave the 4,4 -disulfonic acid 212 - (Equation 67). The same two products 211 and 212 were obtained by reaction of diphenyl sulfide with concentrated sulfuric acid. ... 

One of the characteristic properties of BBB, BBL, and many other similar heterocyclic polymers is their limited solubility. As far as is now known, BBB is soluble only in strong acids such as concentrated sulfuric, benzenesulfonic, methanesulfonic, and concentrated phosphoric acid and in certain aqueous reagents discussed below, in which a chemical reaction modifies the polymer. The vat dyestuffs below ... 

Sulfonic acids are converted to the corresponding acid halides in much the same way as carboxylic acids. Thionyl chloride is the best reagent for the preparation of methanesulfonyl chloride (83%). By heating with a large excess of thionyl chloride, however, p-toluenesulfonic acid is converted into its anhydride (87%). Benzenesulfonyl chloride is made in 80% yield by the action of either phosphorus pentachloride or phosphorus oxychloride at 180° on sodium benzenesulfonate. Chlorosulfonic and fluorosulfonic acids are used in the conversion of sodium p-chloro-benzenesulfonate to the corresponding sulfonyl halides (85 8S>%). ... 

---