Uses of Chlorosulfonic Acid

Other direct methods for the sulfonation of the higher fatty acids are by the use of sulfur trioxide vapor or by the use of chlorosulfonic acid. Indirect methods are also available for the preparation of a-sulfo fatty acids and their salts from an a-bromo fatty acid made by the Hell-Volhard-Zelinsky reaction. The bromo compound may be converted directly to the sodium salt of a sulfonic acid through the Strecker reaction or may be converted to the mercaptan and oxidized to the sulfonate. Sulfonation of the lower fatty acids has been studied by Backer and co-workers. ... 

The use of chlorosulfonic acid illustrates one method by which the direction of sulfonation is altered. It will be recalled (page 289) that the usual method of sulfonation gives a preponderance of the para isomer. 

The use of chlorosulfonic acid with pyridine for alcohol sulfation is often m( titioned in the literature, and this mixture has been used commercially. riu actual reagent in this case is pyridine—SO3 formed by the reaction... 

As the demand for lauryl sulfate steadily increased because of its excellent detergent and foaming properties, serious consideration was given to continuous processes. Several of those proposed are based on the use of chlorosulfonic acid, and this type of continuous operation, employing a reaction solvent, is used commercially. 

The use of chlorosulfonic acid for the synthesis of organic sulfonyl chlorides has been reviewed. The work before 1943 is described with extensive references... 

The use of chlorosulfonic acid for preparation of several important arylsulfonyl chlorides has been described.However, depending on the nature of the substrate and the experimental conditions, reaction with chlorosulfonic acid may also yield diaryl sulfones" or chlorinated products."... 

Silicon compounds containing reactive aryl groups may be chlorosulfonated without loss of the silicon atom by the use of chlorosulfonic acid. Thus, tetraphenoxysilane 451 reacted with excess chlorosulfonic acid at 75-85 C (2j hours) to give the sulfonyl chloride 452. Subsequent reduction of 452 with zinc afforded 4-hydroxyphenylthiol 453 (72% yield, 99.6% purity) this provides an excellent synthetic route to this compound (Equation 140). ... 

C.M. Suter, The Organic Chemistry of Sulfur, Wiley, New York, 1944 Reprinted edition by Intra-Science Research Foundation, Santa Monica, California, 1969, Chapter 3, 195 (this page gives the details of aromatic systems covered and includes the use of chlorosulfonic acid). Chapter 5, p 458 deals with the preparation of aromatic sulfonyl chlorides some of which were made by chlorosulfonic acid, see Tables 2 to 13 (p 463-491). 

The early work on the sulfonation of aliphatic compounds is described in Suter s book there are also several general references " which include the use of chlorosulfonic acid in the sulfonation of aliphatic compounds. Aliphatic compounds are generally less reactive towards sulfonating reagents than aromatic species, because they are less nucleophilic in character and so are less susceptible to attack by an electrophilic reagent like chlorosulfonic acid. 

The chlorosulfonic acid-ether complex is a milder reagent than free chlorosulfonic acid for the sulfation of alcohols and is outstanding in respect of yield and purity of the alkyl hydrogen sulfates 45 produced. The use of chlorosulfonic acid in diethyl ether at low temperature (-50 °C) is a standard method for sulfation of higher (Cg-C28) primary and secondary alcohols. The latter have also been successfully sulfated using a mixture of chlorosulfonic acid in acetic acid the active entity here is probably acetyl sulfate. This method has been adapted for the synthesis of very pure sodium alkyl sulfates for use as detergents thus chlorosulfonic acid and 1-dodecanol were successively added to acetic acid at low temperature (—10 to -15 °C), the solid product was neutralized with sodium carbonate and unreacted alcohols extracted with solvents to give 98.6% pure dodecanyl sodium sulfate. ... 

In the sulfonation of unsaturated alcohols, powerful sulfonating reagents tend to attack the double or triple bond as well as the hydroxyl group consequently, milder reagents are preferred for selective O-sulfation. Studies of the sulfation of oleyl and elaidyl alcohols showed that the purest product (97% purity) was obtained using chlorosulfonic acid-urea, followed by sulfur trioxide-pyridine (96%), sulfamic acid (93%), sulfur trioxide-dioxan (90%) and chlorosulfonic acid-sodium chloride (60%). With sperm oil, the use of chlorosulfonic acid-urea afforded 99% sulfation with 90% retention of the double bond. ... 

The use of chlorosulfonic acid (1.5-1.6 equivalents) converted petroleum-derived unsaturated alcohols (one equivalent) into alkyl sulfates (92% conversion) with good surfactant properties. ... 

In the synthesis of 15, the chlorosulfonation step was achieved by the use of chlorosulfonic acid containing phosphorus pentachloride. Sulfadiazine 5 also has antimalarial properties and other sulfonamides are used as anticonvulsant and antipsycotic drugs. ... 

A specific example is sodium lauryl sulfate (32, = 11) obtained by sulfation of lauryl alcohol (33, n = 11) and extensively used in handwashing of fabrics, shampoos and dentrifices. The sulfation of alcohols has been described in detail in Chapter 5. In this reaction, chlorosulfonic acid is often the preferred reagent and the use of chlorosulfonic acid in ether is the standard procedure for sulfation of higher primary and secondary alkanols (see Chapter 5, p 155). However, in the modem large scale manufacture of detergents by sulfation of alcohols, sulfur trioxide is often the reagent of choice. 

The continuous sulfation of higher alcohols has been achieved by the use of chlorosulfonic acid or sulfur trioxide gas in which the flow of the alcohol and the sulfonating agent is automatically controlled. ... 

Both the sulfone 52 and the disulfonyl chloride 55 may be made by reactions involving the use of chlorosulfonic acid (see Chapter 3, p 29 and Chapter 4, p 74 respectively). A polyarylether sulfone 53 can be efficiently sulfonated by treatment with sulfuric acid followed by chlorosulfonic acid. The reaction mixture was left at 25 °C for 12 hours to yield a sulfonated resin of ion-exchange capacity 0.2 mequiv. Sulfonated polysulfones, useful in reverse osmosis desalination membranes, may be prepared by sulfonation of a commercial polysulfone with chlorosulfonic acid. The polysulfone Udel PI700 can be sulfonated by chlorosulfonic acid or trimethylsilylchlorosulfonate to form proton-conducting membranes for fuel cells and supercapacitors. ... 

Several other heterocyclic compounds can be prepared by cyclizations involving the use of chlorosulfonic acid. For instance, benzylaminoacetals 14, on treatment with the reagent, cyclize to the corresponding isoquinolines 15 (Equation 5). ... 

A recent article claimed that the average annual production of chlorosulfonic acid in Western Europe is 120000 tons, while the comparable figures for the USA and Japan are 67000 and 50 000 tons respectively. Indian annual capacity for chlorosulfonic acid production totals 88 800 tons by seven companies. The largest producer is DMC, followed by Grasim Industries with 16 500 tons Indian production in 1993-94 was estimated to be 73 000 tons. On a global scale, the uses of chlorosulfonic acid are as already reported (see Introduction, p 5). - ... 

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