Laurolactam is an

organic compound In chemistry, organic compounds are generally any chemical compounds that contain carbon- hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. Th ...

from the group of

macrocyclic Macrocycles are often described as molecules and ions containing a ring of twelve or more atoms. Classical examples include the crown ethers, calixarenes, porphyrins, and cyclodextrins. Macrocycles describe a large, mature area of chemistry. ...

lactam A lactam is a cyclic amide, formally derived from an amino alkanoic acid. The term is a portmanteau of the words ''lactone'' + ''amide''. Nomenclature Greek prefixes in alphabetical order indicate ring size: * α-Lactam (3-atom rings) * β-Lact ...

s. Laurolactam is mainly used as a monomer in

engineering plastic Engineering plastics are a group of plastic materials that have better mechanical and/or thermal properties than the more widely used commodity plastics (such as polystyrene, PVC, polypropylene and polyethylene). Being more expensive than st ...

s, such as nylon-12 and copolyamides.T. Schiffer, G. Oenbrink: ''Cyclododecanol, Cyclododecanone, and Laurolactam.'' In: ''Ullmann's Encyclopedia of Industrial Chemistry.'' Wiley-VCH, Weinheim 2002, .

Synthesis

Although a derivative of 12-amino dodecanoic acid, it is made from cyclododecatriene. The triene is hydrogenated to the saturated alkane,

cyclododecane Cyclododecane is an organic compound with the chemical formula (CH2)12. It is a waxy white solid at room temperature, and is soluble in nonpolar organic solvents. It is an intermediate of Nylon 12, polyesters, and synthetic lubricating oils. ...

. For the production of laurolactam, cyclododecane is oxidized with air or oxygen in the presence of

boric acid Boric acid, more specifically orthoboric acid, is a compound of boron, oxygen, and hydrogen with formula . It may also be called hydrogen borate or boracic acid. It is usually encountered as colorless crystals or a white powder, that dissolve ...

and transition metal salts (e.g.

cobalt(II) acetate Cobalt(II) acetate is the cobalt salt of acetic acid. It is commonly found as the tetrahydrate Co(CH3CO2)2·4 H2O, abbreviated Co(OAc)2·4 H2O. It is used as a catalyst. Synthesis and structure Like many other transition metal acetates, cobalt( ...

), obtaining a mixtureH.-J. Arpe: ''Industrielle Organische Chemie.'' 6., vollst. überarb. Aufl., Wiley-VCH Verlag, Weinheim, 2007, . of cyclododecanol and cyclododecanone. This mixture is quantitatively

dehydrogenated In chemistry, dehydrogenation is a chemical reaction that involves the removal of hydrogen, usually from an organic molecule. It is the reverse of hydrogenation. Dehydrogenation is important, both as a useful reaction and a serious problem. At ...

on a copper contact catalyst to cyclododecanone and this reacted with

hydroxylamine Hydroxylamine is an inorganic compound with the formula . The material is a white crystalline, hygroscopic compound.Greenwood and Earnshaw. ''Chemistry of the Elements.'' 2nd Edition. Reed Educational and Professional Publishing Ltd. pp. 431–43 ...

to cyclododecanone oxime. The

oxime In organic chemistry, an oxime is a organic compound belonging to the imines, with the general formula , where R is an organic side-chain and R’ may be hydrogen, forming an aldoxime, or another organic group, forming a ketoxime. O-substitu ...

is rearranged to laurolactam in a

Beckmann rearrangement The Beckmann rearrangement, named after the German chemist Ernst Otto Beckmann (1853–1923), is a rearrangement of an oxime functional group to substituted amides. The rearrangement has also been successfully performed on haloimines and nitrones ...

in the presence of a strong acid. Laurolactam formation 2

An alternative process is the photonitrosation of cyclododecane with

nitrosyl chloride Nitrosyl chloride is the chemical compound with the formula NOCl. It is a yellow gas that is commonly encountered as a component of aqua regia, a mixture of 3 parts concentrated hydrochloric acid and 1 part of concentrated nitric acid. It is a st ...

in the presence of anhydrous hydrogen chloride. The resulting cyclododecanone oxime is extracted with concentrated sulfuric acid and rearranged to laurolactam by heating to 160 °C. The overall yield (photonitrogenation + Beckmann rearrangement) is up to 93%.

Properties

Laurolactam is a water-insoluble, crystalline solid; in technical quality usually beige colored and in pure state (99.9% purity) white. It is soluble in many organic solvents, e. g.

1,4-dioxane 1,4-Dioxane () is a heterocyclic organic compound, classified as an ether. It is a colorless liquid with a faint sweet odor similar to that of diethyl ether. The compound is often called simply dioxane because the other dioxane isomers ( 1,2 ...

benzene Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen ato ...

cyclohexane Cyclohexane is a cycloalkane with the molecular formula . Cyclohexane is non-polar. Cyclohexane is a colorless, flammable liquid with a distinctive detergent-like odor, reminiscent of cleaning products (in which it is sometimes used). Cyclohex ...

. The purification process is carried out conventionally by multistage distillation under reduced pressure. The combination of distillation and crystallization from solution or melt yields very pure laurolactam (> 99%). The risk posed by laurolactam is considered to be low.

Uses

Ring opening polymerization is used to polymerize the monomer to nylon-12. The reaction can be brought about with cationic or anionic initiators or with water. Cationic polymerization with acid is believed to involve the initial O-protonation. Nucleophilic attack by the monomer on the reactive protonated nitrogen, followed by successive ring-opening acylation of the primary amine results in the formation of the polyamide. The

ring-opening polymerization In polymer chemistry, ring-opening polymerization (ROP) is a form of chain-growth polymerization, in which the terminus of a polymer chain attacks cyclic monomers to form a longer polymer (see figure). The reactive center can be radical, anioni ...

of the monomer laurinlactam initially proceeds upon addition of water in a pre-polymerization at about 300 °C under pressure to a

prepolymer In polymer chemistry, the term prepolymer or pre-polymer, refers to a monomer or system of monomers that have been reacted to an intermediate-molecular mass state. This material is capable of further polymerization by reactive groups to a fully c ...

. This prepolymer is reacted in a subsequent polycondensation at ambient or reduced pressure and temperatures of about 250 °C to higher molecular weight

polyamide 12 Nylon 12 is a nylon polymer with the formula CH2)11C(O)NHsub>n. It is made from ω-aminolauric acid or laurolactam monomers that each have 12 carbons, hence the name ‘Nylon 12’. It is one of several nylon polymers. Synthesis Nylon 12 can b ...

( PA 12: - H-(CH₂)₁₁-COsub>n-). Polyamid12

As a comonomer, laurolactam is used together with

ε-caprolactam Caprolactam (CPL) is an organic compound with the formula (CH2)5C(O)NH. This colourless solid is a lactam (a cyclic amide) of caproic acid. Global demand for this compound is approximately five million tons per year, and the vast majority is used ...

for the preparation of copolyamide 6/12.

References

{{Reflist Lactams