Abstract

Sulfonation and sulfation are chemical processes for introducing the sulfur trioxide moiety into organic entities. These processes are utilized in both batch and continuous modes to produce anionic surfactants, cyclic intermediates, dyes, pigments, medicinals, pesticides, sweeteners, lubricant additives, and polymeric specialty chemicals. Reagents for sulfonation and sulfation include sulfur trioxide, its derivatives and adducts, and sulfur dioxide and its derivatives. Liquid sulfur trioxide is the most reactive available reagent and is moderated by vaporization and dilution with inert dry gases, by use of reaction solvents, or by using adducting agents. Commercially important sulfonated and sulfated products are described. Continuous falling film gaseous sulfur trioxide sulfonation–sulfation, the method of choice for sulfonating flowable liquid feedstocks, is emphasized. Choice of reagent depends on the chemistry involved, derived product quality, as well as economic and environmental considerations.