The second type of anionic surfactant is a sulfonate. The most important species is sodium dodecylbenzene sulfonate (LAS) synthesized from the petroleum raw material linear alkylbenzene by sulfur trioxide or its analog. It is the most used surfactant in the world, with good comprehensive performance and high cost performance. Although sodium dodecylbenzene sulfonate is derived from benzene but does not contain free benzene, it is a biodegradable surfactant and there is currently no evidence to prove harmful to humans. Therefore, sodium dodecylbenzene sulfonate is the main surfactant in detergents and dishwashing detergents, and is also widely used in other cleaning products such as hard surface detergents, toilet blocks or laundry tablets. Since sodium dodecylbenzenesulfonate is generally resistant to hard water, it is required to be used in combination with zeolite and polycarboxylate in a phosphorus-free detergent. The α-olefin sulfonate (AOS) is a product obtained by sulfonating another petroleum raw material α-olefin, and can be used in place of sodium dodecylbenzenesulfonate for applications requiring hard water resistance and high foaming.
In order to cater to the trend of biomass chemistry, it also uses natural long-chain raw materials to synthesize sulfonate products. One is sulfonated palm oil methyl ester to obtain fatty acid methyl ester sulfonate (MES), which has strong resistance to hard water and Net washing power, there are already commercially available products that replace sodium dodecylbenzene sulfonate to produce non-phosphorus washing powder. There is also a relatively small fatty alcohol succinic acid monoester sulfonate, which is obtained by esterification of natural fatty alcohol with maleic anhydride and sulfination with sulfite. The irritancy is extremely low and the comprehensive performance is good due to the high price. Only used in some personal care products formulations.
The third type of anionic surfactant is a phosphate salt, which is the smallest variety among the domestic anionic surfactants, and a potassium salt of lauryl phosphate monoester is commonly used. Phosphorus and its products have good human synergy, rich in dense foam, but slightly resistant to hard water. It is used in facial cleanser products in combination with a strong sulfobetaine amphoteric surfactant which is resistant to hard water and water. It combines the advantages of both and has excellent performance, becoming a mainstream facial cleanser formula.