2.2 Fatty alcohol and its alkoxylate sulfate
Fatty alcohol and its alkoxylate sulfate are a class of sulfate ester surfactants prepared by the sulfation reaction of alcohol hydroxyl group with sulfur trioxide. Typical products are fatty alcohol sulfate and fatty alcohol polyoxygen Vinyl ether sulfate and fatty alcohol polyoxypropylene polyoxyethylene ether sulfate, etc.

2.2.1 Fatty alcohol sulfate
Fatty Alcohol Sulfate (AS) is a kind of product obtained from fatty alcohol through SO3 sulfation and neutralization reaction. The commonly used fatty alcohol is coco C12-14. The product is often called K12. The main active substances on the market are 28 %~30% liquid products and active substances are more than 90% powder products. As an anionic surfactant with excellent performance, K12 has applications in toothpaste, detergents, gypsum building materials and biomedicine.

2.2.2 Fatty alcohol polyoxyethylene ether sulfate
Fatty alcohol polyoxyethylene ether sulfate (AES ) is a type of surfactant obtained from fatty alcohol polyoxyethylene ether (EO is usually 1~3) through SO3 sulfation and neutralization. At present, the product on the domestic market has two forms: a paste with a content of about 70% and a liquid with a content of about 28%.
Compared with AS, the introduction of EO group in the molecule makes AES greatly improved in terms of resistance to hard water and irritation. AES has good decontamination, emulsification, wetting and foaming properties, and is easily biodegradable. It is widely used in household washing and personal care. AES ammonium salt has little skin irritation, and is mainly used in some high-end shampoos and body washes.

2.2.3 Fatty alcohol polyoxypropylene polyoxyethylene ether sulfate
Fatty alcohol polyoxypropylene polyoxyethylene ether sulfate, also known as Extended acid salt surfactant, is a type of surfactant that has been studied abroad for more than ten years. Extended surfactant refers to a type of surfactant that introduces PO or PO-EO groups between the hydrophobic tail chain and the hydrophilic head group of the ionic surfactant. The concept of “Extended” was proposed by Venezuelan Dr. Salager in 1995. It aims to extend the hydrophobic chain of surfactants, thereby enhancing the interaction of surfactants with oil and water. This type of surfactant has the following features: extremely strong solubilization ability, ultra-low interfacial tension with various oils (<10-2mN/m), and low critical microemulsion concentration. Such surfactants have good application prospects in tertiary oil recovery, microemulsion vegetable oil, vegetable oil extraction, microemulsion detergent, foam separation, etc.