chemistry Chemistry is the scientific study of the properties and behavior of matter. It is a natural science that covers the elements that make up matter to the compounds made of atoms, molecules and ions: their composition, structure, proper ...

, a fatty amine is loosely defined as any

amine In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent ...

possessing a mostly linear

hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...

chain of eight or more carbon atoms. They are typically prepared from the more abundant

fatty acid In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated or unsaturated. Most naturally occurring fatty acids have an unbranched chain of an even number of carbon atoms, f ...

s, with vegetable or seed-oils being the ultimate starting material. As such they are often mixtures of chain lengths, ranging up to about C22. They can be classified as

oleochemical Oleochemistry is the study of vegetable oils and animal oils and fats, and oleochemicals derived from these fats and oils. The resulting product can be called oleochemicals (from Latin: oleum "olive oil"). The major product of this industry is soa ...

s. Commercially important members include coco amine, oleylamine, tallow amine, and soya amine. These compounds and their derivatives are used as fabric softeners,

froth flotation Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in mineral processing, paper recycling and waste-water treatment industries. Historically this was first used in the mining industry, wher ...

agents (purification of ores),

corrosion inhibitor In chemistry, a corrosion inhibitor or anti-corrosive is a chemical compound that, when added to a liquid or gas, decreases the corrosion rate of a material, typically a metal or an alloy, that comes into contact with the fluid. The effectiveness ...

s, lubricants and friction modifiers. They are also the basis for a variety of cosmetic formulations.

Production and reactions

Fatty amines are commonly prepared from

fatty acids In chemistry, particularly in biochemistry, a fatty acid is a carboxylic acid with an aliphatic chain, which is either saturated and unsaturated compounds#Organic chemistry, saturated or unsaturated. Most naturally occurring fatty acids have an B ...

; which are themselves obtained from natural sources, typically seed-oils. The overall reaction is sometimes referred to as the Nitrile Process and begins with a reaction between the fatty acid and

ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous ...

at high temperature (>250 °C) and in the presence of a metal oxide catalyst (e.g., alumina or zinc oxide) to give the fatty

nitrile In organic chemistry, a nitrile is any organic compound that has a functional group. The prefix '' cyano-'' is used interchangeably with the term ''nitrile'' in industrial literature. Nitriles are found in many useful compounds, including me ...

. : RCOOH + NH₃ → RC≡N + 2 H₂O The fatty amine is obtained from this by

hydrogenation Hydrogenation is a chemical reaction between molecular hydrogen (H2) and another compound or element, usually in the presence of a catalyst such as nickel, palladium or platinum. The process is commonly employed to reduce or saturate organic ...

with any of a number of reagents, including Raney nickel or cobalt, and

copper chromite Copper chromite is an inorganic compound with the formula Cu2Cr2O5. It is a black solid that is used to catalyze reactions in organic synthesis. History The material was first described in 1908. The catalyst was developed in North America by Home ...

catalysts. When conducted in the presence of excess ammonia the hydrogenation affords the primary amines. : RCN + 2 H₂ → RCH₂NH₂ In the absence of ammonia, secondary and tertiary amines are produced. :2 RCN + 4 H₂ → (RCH₂)₂NH + NH₃ :3 RCN + 6 H₂ → (RCH₂)₃N + 2 NH₃

Fatty secondary and tertiary amines

Alternatively, secondary and tertiary fatty amines can be generated by the reaction of

fatty alcohol Fatty alcohols (or long-chain alcohols) are usually high-molecular-weight, straight-chain primary alcohols, but can also range from as few as 4–6 carbons to as many as 22–26, derived from natural fats and oils. The precise chain length varies ...

s and fatty alkyl bromides with (di)alkylamines. For example 1-bromododecane reacts with dimethyl amine: :RBr + HNMe₂ → RNMe₂ + HBr By reaction with tertiary amines, long-chain alkyl bromides give quaternary ammonium salts, which are used as phase transfer catalysts. Secondary and tertiary amines may also be produced by the Leuckart reaction. This reaction effects N-methylation using

formaldehyde Formaldehyde ( , ) ( systematic name methanal) is a naturally occurring organic compound with the formula and structure . The pure compound is a pungent, colourless gas that polymerises spontaneously into paraformaldehyde (refer to section ...

with

formic acid Formic acid (), systematically named methanoic acid, is the simplest carboxylic acid, and has the chemical formula HCOOH and structure . It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. Est ...

as the reductant. These tertiary amines are precursors to

quaternary ammonium salt In chemistry, quaternary ammonium cations, also known as quats, are positively charged polyatomic ions of the structure , R being an alkyl group or an aryl group. Unlike the ammonium ion () and the primary, secondary, or tertiary ammonium cation ...

s used for a variety of applications.

Applications and derivatives

The main application of fatty amines is for the production of the corresponding

s, which are used as fabric softeners and

hair conditioner Hair conditioner is a hair care cosmetic product used to improve the feel, texture, appearance, and manageability of hair. Its main purpose is to reduce friction between strands of hair to allow smoother brushing or combing, which might otherwise ...

s (e.g. Behentrimonium chloride). Fatty amines are also used in

, for the beneficiation of various ores. The amines bind to the surfaces of certain minerals allowing them to be readily separated from those lacking the bound amine. They are also additives in the production of

asphalt Asphalt, also known as bitumen (, ), is a sticky, black, highly viscous liquid or semi-solid form of petroleum. It may be found in natural deposits or may be a refined product, and is classed as a pitch. Before the 20th century, the term ...

References

{{Reflist Amines