Laurolactam

Synthesis

Although a derivative of 12-aminododecanoic acid, it is made from cyclododecatriene. The triene is hydrogenated to the saturated alkane, cyclododecane. For the production of laurolactam, cyclododecane is oxidized with air or oxygen in the presence of boric acid and transition metal salts (e.g. cobalt(II) acetate), obtaining a mixture of cyclododecanol and cyclododecanone. This mixture is quantitatively dehydrogenated on a copper contact catalyst to cyclododecanone and this reacted with hydroxylamine to cyclododecanone oxime. The oxime is rearranged to laurolactam in a Beckmann rearrangement in the presence of a strong acid.{{citation|surname1=Douglass F. Taber, Patrick J. Straney|periodical=Journal of Chemical Education|title=The Synthesis of Laurolactam from Cyclododecanone via a Beckmann Rearrangement|volume=87|issue=12|pages=1392|date= December 2010|language=German|doi=10.1021/ed100599q|url=PDF

An alternative process is the photonitrosation of cyclododecane with nitrosyl chloride 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, benzene or cyclohexane. 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 of the monomer laurinlactam initially proceeds upon the addition of water in a pre-polymerization at about 300 °C under pressure to a prepolymer. 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 ( PA 12: -[NH-(CH2)11-CO]n-).

As a comonomer, laurolactam is used together with ε-caprolactam for the preparation of copolyamide 6/12.

Drug Use

Laurolactam is used in the synthesis of MDL-12330A [40297-09-4]. Although at first glance it appears as though Laurolactam is condensed with cypenamine, the authors stated that cis stereochemistry is chosen. The molecule is said to act as a Calcium Channel Blocker.

References

References

1. T. Schiffer, G. Oenbrink: ''Cyclododecanol, Cyclododecanone, and Laurolactam.'' In: ''Ullmann's Encyclopedia of Industrial Chemistry.'' Wiley-VCH, Weinheim 2002, {{doi. 10.1002/14356007.a08_201.
2. H.-J. Arpe: ''Industrielle Organische Chemie.'' 6., vollst. überarb. Aufl., Wiley-VCH Verlag, Weinheim, 2007, {{ISBN. 978-3-527-31540-6.
3. Patent [https://www.google.de/patents/US8309714 US8309714]: ''Process for producing laurolactam.'' invent1: J. Kugimoto et al., assign1: Ube Industries, Ltd., erteilt am 13. Nov. 2012.
4. Y. Furuya et al.: ''Cyanuric Chloride as a Mild and Active Beckmann Rearrangement Catalyst.'' In: ''J.Am.Chem.Soc.'' 127, Nr. 32, 2005, S. 11240–11241, {{doi. 10.1021/ja053441x
5. {{Cite patent. ""
6. "Method for isolation of laurolactam from a laurolactam synthesis process stream".
7. "OECD: Screening Information Dataset (SIDS) Initial Assessment Report (SIAR)".
8. Stevens, M. P. Polymer Chemistry: An Introduction, Oxford University Press: New York, 1999.
9. "Continuous polymerization method of laurolactam and apparatus therefor".
10. "Copolyamides containing caprolactam and laurolactam, process for the preparation thereof and use thereof for heat-sealing textiles".
11. Castaer, J.; Hillier, K.; RMI-12,330A. Drugs Fut 1979, 4, 12, 893.
12. Johann M. Grisar, Thomas R. Blohm, & Edward M. Roberts, {{US patent. 4126611 (to Richardson Vicks Inc).