Linear alkylbenzenesulfonates applications

Unsulfonated linear alkylbenzene and linear alkylbenzene sulfones are the main components of unsulfated matter in linear alkylbenzenesulfonate, an anionic surfactant. These residual products can be quantified by high-temperature capillary GC and its application to alkylbenzenesulfonate improves its synthesis process (Molever, 2005). 

The term alkylbenzenesulfonate (ABS) is generally applied to the branched-chain products, which are only biodegradable with difficulty. ABS is not used in developed countries except for specialty applications where it will not reach natural waters (e.g., as an emulsifier for agricultural chemicals). As opposed to ABS, linear alkylbenzenesulfonate (LAS) is rapidly biodegradable under aerobic conditions. The feedstocks are synthesized by Friedel-Crafts alkylation of benzene. Depending on the alkylation catalyst, phenyl substitution may be uniform on the secondary carbons, or higher in the 2 position. (The 1-phenyl isomer is not found.) Subsequent sulfonation with oleum or sulfur trioxide produces mainly the para isomers. LAS has the lowest cost of any surfactant and is used throughout the world. It is sensitive to water hardness. 

Most published work deals with the environmental determination of the dominant anionic surfactant, linear alkylbenzenesulfonate (LAS). The same methods are applicable to the less common branched-chain analog, ABS. Thorough environmental studies not only track the amount of intact LAS in various matrices, but also follow the alkyl chain distribution in order to reach an understanding of which homologs are dominant in the matrix due to the selective biodegradation of other homologs. 

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