The detergent action of surfactants is a fundamental property that gives surfactants their greatest practical utility. It is involved in the daily lives of thousands of households. Moreover, it is being increasingly applied in various industries and all kinds of industrial production.
Surfactants are the main active ingredients in detergents; without surfactants, there would be no synthetic detergents. Among all types of SAA, anionic surfactants are the earliest used and most widely applied type of surfactants, with current demand accounting for more than 50%. Anionic surfactants will continue to occupy a dominant position for a period of time in the future.
1 Anionic Surfactants
The types of anionic surfactants used as detergents mainly include fatty acid salts (soaps), alkylbenzene sulfonates (ABS), fatty alcohol sulfates (AS), fatty alcohol polyoxyethylene sulfates (AES), α-olefin sulfates (AOS), fatty alcohol polyoxyethylene carboxylates (AEC), and fatty acid methyl ester sulfonates (MES), etc.
1.1 Soap
The surface-active part of soap molecules carries a negative charge, among which long carbon chain fatty acid sodium and potassium salts account for about 25%. This most widely used soap has the advantages of abundant raw materials, convenient preparation, and low price. Industrially, it is generally made from fats such as beef tallow and mutton tallow through saponification with strong alkali, followed by salting out and separation of glycerol. Its biggest drawback is that when it encounters divalent and trivalent metal ions such as Ca²⁺, Mg²⁺, Fe²⁺, etc., in aqueous solution, it will form calcium soap or magnesium soap with very low solubility, thus losing the due cleaning properties of soap.
1.2 Alkylbenzene sulfonate (ABS)
Sodium alkylbenzenesulfonate (R-C6H6-SO3Na) is a very important anionic surfactant. It has good solubility in water and is almost completely ionized. Its calcium and magnesium salts have relatively high solubility in water, so it has good hard water resistance. Among alkylbenzenesulfonates, linear alkylbenzene (LAS) is low in price, has strong detergency, is easily biodegradable, and is environmentally friendly. Therefore, so far, no other surfactant used as a detergent active ingredient can match LAS in terms of technical performance and economic benefits. It is praised by the global synthetic detergent industry as the main force of synthetic detergents. It is mainly used as an industrial and household detergent. Representative products: Sodium dodecylbenzenesulfonate has excellent washing effect, and sodium octadecylbenzenesulfonate has the strongest detergency among the sodium alkylbenzenesulfonate series.
1.3 α-Olefin Sulfonate (AOS)
AOS is an excellent-performing detergent active substance. It is mainly used in hand sanitizers, shampoos, bubble baths, dishwashing detergents, industrial cleaning agents, and laundry detergents.
1.4 Methyl Ester Sulfonate (MES)
R is an alkyl group, and R’ is a methyl group. The detergency is better when R is C16 and C18, and the hard water resistance is the best when R is C14. MES is a surfactant made from natural oils and fats, with good washing performance and strong soap-calcium dispersing power. It has excellent compatibility with zeolite and is suitable for manufacturing phosphate-free laundry detergent. Its calcium soap dispersing power is much higher than that of LAS, so it is beneficial to the production and application of compound soap and soap-based laundry detergent.
1.5 Fatty Alcohol Sulfate (AS) and Fatty Alcohol Ether Sulfate (AES)
AS has the general formula ROSO3Na, where R is C14~C16, and it has good detergency; AES has the general formula RO(C2H4O)nSO3Na, where R is C14~C15 and n=1—2, and it also has good detergency. Both AS and AES have good biodegradability, strong detergency, and good foaming properties. They are suitable for formulating high-foam detergents. They are suitable for easy-care or wool detergents and are widely used in bubble baths, shampoos, cosmetics, hand dishwashing detergents, vegetable detergents, household detergents, etc.
Non-ionic surfactants have good detergency against oily soils and strong ability to prevent recontamination of synthetic fibers. They have relatively strong resistance to hard water and high concentrations of electrolytes. The greatest advantage of polyoxyethylene non-ionic surfactants is the adjustability of the hydrophobic and hydrophilic moieties. The number of EO can be adjusted to adapt to various substrates, achieving the best detergency.
2.1 Polyoxyethylene alkyl alcohol ether
General formula: RO(C₂H₄O)ₙH, where R = C₁₂~C₁₈ and n is adjustable. This type of compound has high detergency, which is manifested in the following aspects: a low critical micelle concentration (cmc), meaning it still has high cleaning power at low concentrations, strong detergency, and anti-soil redeposition properties when washing synthetic fibers. In addition, it has good low-temperature detergency. It is a white to pale yellow paste at room temperature. When dissolved in water, it has emulsifying, cleaning, and wetting properties. It is mainly used in household and industrial detergents as well as metal cleaning agents.
2.2 Polyoxyethylene alkylphenol ether
In the formula, R is mainly octyl, nonyl, and dodecyl groups; n is adjustable. They are characterized by strong ability to remove oil stains and fats. Representative products include the OP series, OPE series, and SOPE series. Their main properties are strong resistance to acids, alkalis, and hard water, and they function as detergents, wetting agents, emulsifiers for metal processing, and industrial cleaning agents.
2.3 Alkyl Polyglycoside (APG)
Alkyl glycoside is praised as a new type of world-class non-ionic surfactant.
Advantages of APG: 1. High surface activity and very low surface tension; 2. No cloud point and high-temperature stability; 3. Excellent detergency, strong foaming power, wetting and emulsifying properties, and dispersion stability; 4. Superior to any existing type of surfactant in terms of non-toxicity, low skin irritation, and biodegradability. (Outstanding advantages and characteristics).
Therefore, it is particularly favored by many fields such as the washing industry, cosmetics industry, food processing industry, and pharmaceutical industry. Moreover, due to its characteristics of being easy to rinse and leaving no stains, it is especially suitable for use as tableware detergent, bottle cleaner, etc.
APG is used as a detergent in roughly the following aspects:
Bath and hair detergents: Products made using APG are mild and non-irritating to the skin, with rich and fine foam. They can also play an antistatic role when used for shampooing. Most of these products are liquid, but they can also be made into soap bars. Dishwashing detergents: Dishwashing detergents made from APG have good foaming properties, are mild to the skin, leave a good hand feel after use, are easy to rinse, and leave no traces.
Laundry detergent: APG is used in laundry detergents and has excellent detergency. It can be used for cleaning various fabrics (such as cotton, wool, polyester, etc.). It can effectively remove dirt and oil stains. At the same time, it has softening properties, antistatic properties, and anti-shrinking properties. And it can be made into laundry detergents that still have excellent detergency when used in hard water.
Hard surface cleaning: In addition to being used for dishwashing, APG can also be used for cleaning other types of hard surfaces. Detergents under strong acid conditions can be formulated using APG as the active component. The APG therein also has the function of preventing ferrous metals from being oxidized and corroded by acids.
Its molecular structure contains both positive and negative charges. Due to the particularity of its molecular structure, it has the following characteristics during use: low toxicity and low irritation to the skin and eyes; good biodegradability and compatibility; good wettability, detergency, and foaming properties. There are the following types when used as a detergent.
3.1 N-acyl amino acid type
They are mainly used as the base material for shampoos and cleaning agents. They can resist weak acids and hard water.It has low irritation and low toxicity, and can be used in cosmetics.It has strong calcium soap dispersing power, detergency, and emulsifying power. In the textile industry, it is used as a detergent and emulsifier, and is suitable for washing silk and wool due to its poor degreasing power.
3.2 Betaine type
Betaine-type zwitterionic surfactants have good detergency on cotton fabrics and polyester/cotton blended fabrics, especially hydroxyl sulfobetaine, which has more advantages in the washing process. For example: dodecyl dimethyl betaine is a colorless or light yellow transparent liquid. It is cationic in acidic media and anionic in alkaline media. It is easily biodegradable. This product has excellent foaming properties, can make hair soft, and is suitable for manufacturing non-irritating shampoos with conditioning effects on hair, baby shampoos, etc. Due to its good hard water resistance, it is used in the preparation of hard water detergents. It can also be used as a fungicide.
Post time: Mar-17-2026