SULFONATION AND SULFATION

Sulfonation and sulfation, chemical methods for iatroduciag the SO group iato organic entities, are related and usually treated joiatiy. It is estimated that these methods were utilized ia approximately 1000 operational plants throughout the world, including about 170 U.S. plants as of the mid-1990s (1,2). 

Sulfation is defined as any process of introducing an SO group into an organic compound to produce the characteristic C—OSO configuration. Typically, sulfation of alcohols utilizes chlorosulfuric acid or sulfur trioxide reagents. Unlike the sulfonates, which show remarkable stability even after prolonged heat, sulfated products are unstable toward acid hydrolysis. Hence, alcohol sulfuric esters are immediately neutralized after sulfation in order to preserve a high sulfation yield. 

In sulfamation, also termed A/-sulfonation, compounds of the general stmcture R2NSO2H are formed as well as their corresponding salts, acid hahdes, and esters. The reagents are sulfamic acid (amido—sulfuric acid), SO —pyridine complex, SO —tertiary amine complexes, ahphatic amine—SO. adducts, and chlorine isocyanate—SO complexes (3). 

Apphcation chemists are most interested in physical and functional properties contributed by the sulfonate moiety, such as solubility, emulsification, wetting, foaming, and detersive properties. Products can be designed to meet various criteria including water solubility, water dispersibility, and oil solubility. The polar SO moiety contributes detersive properties to lube oil sulfonates and dry-cleaning sulfonates. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

Product class Value, /kg Volume Value Change from 1982—1991, %  

It is convenient to classify sulfonates into four main chemical types (1) aliphatic and alicyclic, (2) aromatic, (3) heterocyclic, and (4) N-sulfo-nates or sulfamates. The first three types have the —SO2OH group on carbon, the chemical nature of which determines the classification. Thus, CeH60CH2S020Na (sodium phenoxymethanesulfonate) would be considered an aliphatic sulfonate. 

For practical reasons, it is also useful to refer to three other types of sulfonates, namely, those derived from petroleum fractions, from lignin, and from fatty oils. These materials are mixtures of indeterminate or variable composition, probably comprising one or more of the main chemical types of sulfonates together with sulfates and other sulfur compounds, and are made largely by empirical procedures. All three types are commercially important. 

Sulfates may be classified as sulfated alkenes, alcohol sulfates cyclic sulfatesy sulfated carbohydrates and sulfated nitrogenous polysaccharides. 

Sulfonating and sulfating agents are of two types— inorganic and organic. The latter type is employed in the condensation procedures. 

Sulfamates include a herbicide, a sweetening agent, and a blood anticoagulant. 

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