- What is fatty alcohol
Fatty alcohols are aliphatic alcohols with carbon chains of 8 to 22 carbon atoms. Fatty alcohols usually have an even number of carbon atoms and a hydroxyl group attached to the end of the carbon chain.
They are one of the raw materials for surfactants used in detergents, with the general formula ROH. For detergent-grade alcohols, R is generally a hydrocarbon group of C12 to C18. Such high-carbon fatty alcohols inherently possess amphiphilic properties, meaning their molecules contain both hydrophobic groups such as hydrocarbon chains and hydrophilic groups such as hydroxyl groups. However, due to their very low solubility in water, it is necessary to add hydrophilic groups or convert the hydroxyl group into a sulfate group. Only when the hydrophilic-lipophilic balance value reaches the required level, so that the fatty alcohol derivative gains sufficient hydrophilic groups to dissolve in water and form aggregates (micelles, does the fatty alcohol derivative act as a surfactant. For example, dodecanol is insoluble in water, but when it is converted into sodium dodecyl sulfate, its water solubility improves due to the introduction of a sulfate group (-SO₃⁻), enabling it to form micelles in water. At a certain concentration, it exhibits excellent surface activity. Leveraging this property, people have produced a variety of surfactants with outstanding performance using fatty alcohols as raw materials.
2.The development process of fatty alcohols
Fatty alcohols were initially produced from spermaceti. The resulting mixed fatty alcohols, after sulfonation and neutralization, formed sulfates, which were one of the earliest anionic detergents. Later, coconut oil, palm oil, and beef tallow, which are relatively abundant sources, were developed and used as raw materials. The fatty acids obtained through hydrolysis were then reduced to alcohols, collectively referred to as natural fatty alcohols. Following the development of the petrochemical industry, fatty alcohols produced using petroleum products as raw materials became known as synthetic fatty alcohols. Relatively important methods for producing fatty alcohols include high-pressure hydrogenation, the Ziegler process, and the oxo synthesis process. If a hair mask contains unsaturated fatty alcohols, it can repair and nourish hair; adding fatty alcohols to lip gloss enhances the smoothness of the product during application.
3.Production method of fatty alcohols
3.1High-Pressure Hydrogenation Method
Fatty alcohols are obtained through high-pressure hydrogenation using animal and vegetable oils as raw materials. Industrially, the raw oil is first pretreated and subjected to alcoholysis (i.e., transesterification) to convert it into fatty acids before hydrogenation. Fatty alcohols can also be produced by direct hydrogenation of fatty acids or hydrogenation after esterification. Direct hydrogenation of fatty acids to produce fatty alcohols imposes high material requirements on equipment.
Chemical reaction equation for hydrogenation of fatty acids to fatty alcohols:
RCOOH + 2H₂ → RCH₂OH + H₂O
Chemical reaction equation for hydrogenation of fatty acid esters to fatty alcohols:
RCOOR′ + 2H₂ → RCH₂OH + R′OH
The high-pressure hydrogenation method includes fixed-bed process and suspended-bed process, but their basic technological processes are identical.
3.2. Ziegler Method
Using ethylene as a raw material to react with trialkylaluminum, aluminum alkoxide compounds are produced through chain growth and oxidation, and then fatty alcohols are obtained via hydrolysis, neutralization and fractional distillation.
Invented by K. Ziegler in 1954, this method was first commercially applied by Continental Oil Company of the United States in 1962, producing straight-chain even-carbon alcohols. The main reactions of this production method include the following steps:
Preparation of triethylaluminum (hydrogenation and addition reaction):
Al + H₂ + 2Al(C₂H₅)₃ → 3Al(C₂H₅)₂H
3Al(C₂H₅)₂H + 3C₂H₄ → 3Al(C₂H₅)₃
Preparation of alkylaluminum (chain growth reaction):
Al(C₂H₅)₃ + 3nC₂H₄ → R₃Al
Preparation of aluminum alkoxide (oxidation reaction):
R₃Al + O₂ → Al(OR)₃
Preparation of fatty alcohols (hydrolysis reaction):
Al(OR)₃ + H₂SO₄ → Al₂(SO₄)₃ + 3ROH
or
Al(OR)₃ + H₂O → Al₂O₃ + 3ROH
3.3. Oxo Synthesis Method
Olefins, carbon monoxide and hydrogen are synthesized into aldehydes under catalyst and pressurized conditions. The aldehyde has one more carbon atom than the raw olefin. Fatty alcohols are obtained by hydrogenation of the aldehydes.
This olefin hydroformylation reaction (OXO reaction) was discovered by German chemist O. Roelen in 1938.
The OXO reaction is as follows:
Hydroformylation reaction
4.Applications and Market Development of Fatty Alcohol Products
Natural high-grade fatty alcohols serve as basic raw materials for fine chemical products such as detergents, surfactants and plastic plasticizers. Thousands of fine chemical products are manufactured from them, which are widely used in sectors including chemical industry, petroleum, metallurgy, textiles, machinery, mining, construction, plastics, rubber, leather, papermaking, transportation, food, medicine and health, daily chemical industry and agriculture.
Fatty alcohols can be used to produce numerous derivatives. Alcohol-based surfactants have been the fastest-growing category among all types of surfactants since the 1980s. As active detergent ingredients, they feature excellent properties including strong detergency, good compatibility, low foaming, ready biodegradability, hard water resistance and good washing performance in low-temperature water. They are gradually replacing linear alkylbenzene sulfonates (LAS) and dodecylbenzenesulfonic acid to become the third-generation detergent raw materials. The most representative products here include AEO3 to AEO9 synthesized from fatty alcohols and ethylene oxide, which can be further sulfonated to produce AES. These alcohol-based surfactants have a wide range of applications and large market demand, are closely related to daily life and the improvement of living quality, and boast broad actual and potential markets. Therefore, they provide a relatively vast development space for the production of fatty alcohols, especially natural fatty alcohols.
Plastic additives are auxiliary raw materials for the plastics industry, and the additive industry develops in tandem with the plastics industry. The rapid development of China’s plastics industry is well known. In 1985, the global consumption of various plastic additives reached 13 million tons, and plasticizers are among the most widely used plastic additives. At present, the foreign production capacity of plasticizers has exceeded 4.5 million tons, while China’s capacity has surpassed 500,000 tons. Among plasticizers, dibutyl phthalate (DBP) and dioctyl phthalate (DOP) account for a major share of output. Besides phthalic anhydride, butanol and octanol are also key raw materials in their production. At present, China consumes more than 300,000 tons of butanol and octanol annually to produce these two plasticizers. However, butanol and octanol have relatively short carbon chains, and plasticizers produced from them can no longer meet the development needs of the plastics processing industry in terms of heat resistance, weather resistance and electrical insulation. Currently, long-chain fatty alcohols such as C10, C12, C14, C16 and C18 alcohols are being tested to replace butanol and octanol, which can produce plastic products with excellent heat resistance, weather resistance and electrical insulation, thus expanding the applications of plastics. Therefore, the application prospects of long-chain fatty alcohols in the plastic plasticizer industry are quite promising.
Natural fatty alcohols have more advantages than synthetic alcohols in daily chemical applications. Even if their physical and chemical quality indicators are identical, consumers still prefer natural alcohols, which has become a prevailing “green” trend. Hence, natural fatty alcohols are ideal raw materials in the cosmetics industry for the production of products such as liquid and ointment soaps, toothpastes and cosmetic emulsions.
Post time: Apr-02-2026