A significant product in the oleochemical industry—fatty amine

Fatty amines refer to a large class of organic amine compounds with carbon chain lengths in the range of C8-C22. Similar to general amines, they are categorized into primary amines, secondary amines, tertiary amines, and polyamines. The classification into primary, secondary, and tertiary amines depends on the number of hydrogen atoms in ammonia replaced by alkyl groups.

Fatty amine is one of the three major intermediates in the chemistry of fats (fatty alcohols, fatty acids, and fatty amines). Currently, the industrial production of fatty amines mostly involves reacting natural fatty acids with ammonia to produce fatty nitriles, and then using fatty nitriles as raw materials to generate fatty amines with the catalytic action.

Higher fatty amines can be produced from natural fats or synthetic raw materials, mainly using fatty acids or higher fatty alcohols as raw materials. The industrial production of higher fatty amines and their derivatives, using fatty acids derived from fat sources, began in the 1940s. The fatty amine industry started in the 1950s, experienced significant development in the 1970s, during which a new process for the one-step production of dimethylalkylamines from alcohols and amines was developed. New routes and technologies for synthesizing fatty amines, such as the production of fatty amines from α-olefins by U.S. Ethyl Corporation and hydroxyamines from α-olefins by Japan's Daisero Corporation, have been introduced. In recent years, there have been some improvements in the production of higher fatty amines from fatty acids through nitriles, focusing on energy efficiency, enhanced catalyst activity, suppression of side reactions, and continuous process integration.

With the continuous improvement of people's living standards, the per capita consumption of fatty amine surfactants will greatly increase. The raw materials for fatty amine surfactant products mainly come from animal and vegetable oils and fats, which are renewable resources and biodegradable. Fatty amines and their derivatives are mainly used as cationic surfactants. The raw materials for fatty amine surfactant products can also come from synthetic sources. Currently, cationic surfactants account for 8-9% of the global production of all synthetic surfactants, and the growth rate of fatty amine production (average 4%) is higher than the overall average growth rate of surfactants (2%-4%). The per capita consumption of fatty amine surfactants in China is less than one-tenth of that in the United States, indicating significant market potential. Therefore, researching the development and application of fatty amines is of great significance.

Properties of Fatty Amines

Fatty amines are organic derivatives of ammonia. Short-chain fatty amines (C8-10) have some solubility in water, while long-chain fatty amines are generally insoluble in water. They exist in liquid or solid form at room temperature and exhibit alkalinity. As organic bases, they can have irritating and corrosive effects on the skin and mucous membranes.

Fatty amines undergo specific reactions characteristic of their nature. These reactions include salt formation, quaternization, ethoxylation, nitrile ethylation, hydrogenation, alkylation, amide formation, synthesis of amphoteric amines, oxidation, Mannich reaction, and others. These chemical properties determine the extensive applications of fatty amines and their derivatives.

Applications of Fatty Amines and Their Derivatives

Fabric Softeners: Over 50% of quaternary ammonium salt production is used in fabric softeners. Double long-chain fatty alkyl tertiary amines, after quaternization, serve as fabric softeners. The most significant variety is didecyl dimethyl ammonium chloride used as a fiber conditioner in the final rinse of household laundry, providing softness and antistatic properties to fabrics.

Antistatic Agents: Fatty primary amines, in combination with 2 moles of ethylene oxide, are primarily used as antistatic agents in the plastic industry. Ethoxylated amines, being insoluble in plastics, migrate to the surface, absorbing atmospheric moisture and rendering the plastic surface antistatic.

Bactericides and Algicides: Some tertiary amines, after quaternization, serve as bactericides. Quaternary ammonium salts with a benzyl group are commonly used for various purposes such as domestic, medical, and industrial disinfection, cleaning, and mold prevention, as well as algae control in swimming pools and disinfection during laundry processes. They are also employed in oil fields to control microorganisms.

Bentonite Modification: Preparation of fatty amine-modified bentonite.

Anticaking Agents: Primary amines and their salts can be effective anticaking agents for fertilizers or explosives. Fatty amines used for anticaking agents in explosives require a higher solidification point.

Pigment Ink Dispersants: Tertiary amines are used as dispersants for pigments, reducing milling time and increasing production yields. Fatty diamines and polyamines are crucial dispersants for inks and pigments.

Oilfield Chemicals: Lignosulfonates or sulfonated alkali lignins react with dodecylamine to form lignosulfonate amines, which, when combined with petroleum sulfonates, act as surfactants. They effectively reduce surface tension, facilitating emulsification and viscosity reduction, enhancing crude oil recovery.

Corrosion Inhibitors: Alkylpropylenediamines are commonly used corrosion inhibitors, playing a crucial role in the regeneration process in oilfields.

Emulsifiers: Primary amines are used in the production of quaternary ammonium salt-type asphalt emulsifiers. These emulsifiers find widespread use in the construction and maintenance of high-grade roads, reducing labor and improving the lifespan of road surfaces.

Personal Care Industry Applications: Oxidized amines derived from primary amines are primarily used in the formulation of daily cleaning products, including conditioning shampoos, bath lotions, facial cleansers, foaming agents, and mild scouring agents. In cosmetics, they serve as moisturizers, emulsifiers, thickeners, and antimicrobial preservatives. Betaines, a type of amphoteric surfactant, are synthesized from dimethyl tertiary amines and chloroacetic acid and find applications in shampoos, premium detergents, and baby cosmetics.

There are many more applications of fatty amines beyond those listed here. The demand for high-quality fatty amine products is increasing, and the application of fatty amines is evolving from general-purpose to specialized formulations.