Reactions of Chlorosulfonic Acid

Intermediate formation of formyl chloride is not necessary since the actual alkylating agent, HCO", can be produced by protonation of carbon monoxide or its complexes. However, it is difficult to obtain an equimolar mixture of anhydrous hydrogen chloride and carbon monoxide. Suitable laboratory preparations involve the reaction of chlorosulfonic acid with formic acid or the reaction of ben2oyl chloride with formic acid ... 

A novel, mild system for the direct nitration of calixarenes has been developed using potassium nitrate and aluminum chloride at low temperature. The side products of decomposition formed under conventional conditions are not observed in this system, and the p-nitro-calixarenes are isolated in 75-89% yields.17 Such Friedel-Crafts-type nitration using nitryl chloride and aluminum chloride affords a convenient system for aromatic nitration.18 Nitryl chloride was previously prepared either by the oxidation of nitrosyl chloride or by the reaction of chlorosulfonic acid with nitric acid. However, these procedures are inconvenient and dangerous. Recently, a mixture of sodium nitrate and trimethysilyl chloride (TMSC1) has been developed as a convenient method for the in situ generation of nitryl chloride (Eq. 2.6). 

Reaction of chlorosulfonic acid with mono- [141] or disazo dyes [142] yields sulfonyl chlorides, which can then be transformed into cationically substituted sulfonamides by reaction with dialkylaminoalkylamines. The coupling product of diazotized 2-anisidine with 2-hydroxynaphthoic acid arylide upon such treatment dyes paper red, and the azo dye from tetrazotized dianisidine and l-phenyl-3-methyl-5 -pyrazolone gives yellowish orange shades. 

Critical surveys have shown that the older methods for the preparation of nitryl chloride are inefficient and yield impure products.1-7 Reasonably pure nitryl chloride was first prepared by Schumacher and Sprenger1-3 in 1929 by the reaction of nitrosyl chloride with ozone the preparation from chlorosulfonic acid and nitric acid was reported later.4 Recently, Schmeisser has obtained nitryl chloride from nitrogen(Y) oxide and phosphorus(V) chloride.5 The reaction of chlorosulfonic acid with nitric acid8-10 is probably the most convenient method for preparing large quantities of nitryl chloride of satisfactory purity. 

Derivation Reaction of chlorosulfonic acid with nitric acid. 

The reaction of chlorosulfonic acid with bromochloromethane was known, but provided low yields and poor conversions. In reviewing this example, we considered that chloroiodomethane could offer both improved yields and a better opportunity for further reaction development. 

Chlorosulfonic acid reacts violently w Ah water. Open containers of chlorosulfonic acid will fume upon exposure to atmospheric moisture owing to the reaction of chlorosulfonic acid with water to give HCI and SO3, both of which are noxious and corrosive gases. Measure and transfer this acid only in the hood. Several graduated cylinders should be kept in the hood for all students to use for measuring the volume of chlorosulfonic acid needed. 

Form Supplied in crystalline white solid widely available. Preparative Methods reaction of chlorosulfonic acid and pyridine in CHCls or reaction of sulfur trioxide and pyridine. Handling, Storage, and Precautions corrosive reacts quantitatively with hot H2O to give pyridine and sulfuric acid. Use in a fume hood. 

Aromatic hydrocarbons also react smoothly with an equimolar amount of chlorosulfonic acid or an excess of the reagent to yield either the sulfonic acid or the sulfonyl chloride (Equations 6 and 7). The direct conversion of aromatic compounds into their sulfonyl chlorides (chlorosulfonation or chlorosulfonylation) is probably the most important reaction of chlorosulfonic acid because sulfonyl chlorides are intermediates in the synthesis of a wide range of sulfonyl derivatives. The process is of wide application because many substituents on the aromatic ring, e.g. alkyl, alkoxy, amide, carboxy, cyano, hydroxy, nitro and multiple bonds are unaffected by the reagent. 

Reaction of Chlorosulfonic Acid with Miscellaneous Compounds... 

The reaction of chlorosulfonic acid with alkenes may be affected by attached groups, e.g. electron-withdrawing halogen and carboxylic acid moieties. 

Methyl chlorosulfonate 74 may be prepared by reaction of chlorosulfonic acid with either methyl sulfate or methyl chloroformate (Equations 28 and 29). ... 

Substituted and unsubstituted aliphatic aldehydes react with the sulfur triox-ide-p5nidine complex (obtained by reaction of chlorosulfonic acid with pyridine) in boiling 1,2-dichloroethane to give good yields of the betaine salts 81 (Equation... 

Extensive studies of the reaction of chlorosulfonic acid and other formaldehyde-generating chemicals, have been carried out by Fuchs Mid Katscher. The results have been reviewed in detail by Jackson, and they demonstrate that formaldehyde can react with chlorosulfonic acid to give a variety of different products 82-85 depending on the reaction conditions. When the reaction is carried out below 70 °C, followed by distillation of the mixture under reduced pressure (14 mmHg), the products were chloromethyl chlorosulfonate 84 and methylene sulfate 82. The initial step of the reaction probably involves protonation of the carbonyl group of the aldehyde by chlorosulfonic acid and addition of the chlorosulfonate anion giving hydroxymethyl chlorosulfonate which, by chlorination, yields chloromethyl chlorosulfonate 84 (Scheme 7). 

The reaction of chlorosulfonic acid with the first three alkanoyl chlorides was extensively investigated by Krajcinovic and afforded some interesting results which were reviewed by Jackson. ... 

Reactions of Chlorosulfonic Acid with Heterocyclic Compounds 187... 

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