Linear Alkylbenzene Sulfonic Acid (LABSA)

About This Product

Linear alkylbenzene sulfonic acid, LABSA or LAS acid, CAS number 27176-87-0, is made by sulfonating linear alkylbenzene, normally with sulfur trioxide. It is a dark brown, viscous, strongly acidic liquid; the commercial grade is quoted at 96 percent active matter and is described by the alkyl chain length of its feedstock, typically C10 to C13. LABSA is sold as the acid rather than the salt because the acid is the concentrated, transportable form. At 96 percent active it carries almost no water, whereas the sodium salt it becomes is normally handled as a 30 to 50 percent slurry or paste. The formulator neutralises it in their own plant, with caustic soda for the sodium salt used in powders and most liquids, or with potassium hydroxide or triethanolamine where a more soluble salt is wanted, and that step is strongly exothermic and has to be cooled and pH-controlled. Two figures decide quality in practice: free oil, the unsulfonated residue that dulls foam and darkens the finished product, and colour on the Klett scale. Because the alkyl chain is linear rather than branched, the material is readily biodegradable, which is the reason branched dodecylbenzene sulfonate was abandoned for it. It is used to make the sodium salt that is the workhorse anionic surfactant of laundry powders, detergent bars, dishwashing liquids and hard-surface cleaners, and as an emulsifier and acid catalyst in industrial formulations. Bio Green Chem supplies LABSA at 96 percent minimum active matter in 215 kg drums or IBC tanks, with free oil, colour and sulfuric acid content confirmed on the batch certificate of analysis. It is corrosive to skin and eyes; handle to the safety data sheet.