Linear Alkylbenzene Sulfonic Acid (LABSA)

About This Product

Linear alkylbenzene sulfonic acid (LABSA, or LAS acid; CAS 27176-87-0; HS 3402.11) is produced by sulfonating linear alkylbenzene, usually with sulfur trioxide, giving a strongly acidic, dark brown, viscous liquid. Commercial material is quoted at 96% active matter and identified by the chain length of its alkylbenzene feed, normally C10 to C13.

Detergent makers buy the acid rather than the salt because it is the concentrated, economical form to ship: at 96% active it contains almost no water, whereas the sodium salt is normally handled as a 30 to 50% slurry or paste. The formulator neutralises it on site, with caustic soda for the sodium salt used in powders and most liquids, or with potassium hydroxide or triethanolamine when a more soluble salt is wanted; the reaction releases a lot of heat and needs cooling and pH control. Batch quality comes down to two results: free oil, the unsulfonated alkylbenzene that weakens foam and darkens the finished product, and colour on the Klett scale. The linear chain is also why LAS displaced branched dodecylbenzene sulfonate: the linear molecule biodegrades far more readily.

Its main use is as the precursor of sodium LAS, the anionic surfactant behind laundry powders, detergent bars, dishwashing liquids and hard-surface cleaners. It also works as an emulsifier and acid catalyst in industrial formulations.

BG Petro Chemicals supplies LABSA at 96% minimum active matter in 215 kg drums or IBC tanks, with free oil, colour and sulfuric acid content reported on each batch certificate of analysis; current specifications and safety data are available on request. The acid is corrosive to skin and eyes, so handle it according to the safety data sheet.