11-aminoundecanoic acid

Structural formula
General
Surname	11-aminoundecanoic acid
other names	ω-aminoundecanoic acid
Molecular formula	C 11 H 23 NO 2
Brief description	white crystalline powder
External identifiers / databases
CAS number 2432-99-7 EC number 219-417-6 ECHA InfoCard 100.017.652 PubChem 17083 ChemSpider 16168 Wikidata Q15632699
properties
Molar mass	201.31 g mol −1
Physical state	firmly
density	1.1720 g cm −3 (26.1 ° C)
Melting point	188-191 ° C , 190.3-192.4 ° C at 1013hPa
Vapor pressure	2.07 · 10 −7 (1013 Pa) at 25 ° C
solubility	800–850 mg · l −1 at 25 ° C, 2 g · l −1 at 20 ° C
safety instructions
GHS labeling of hazardous substances no GHS pictograms H and P phrases H: no H-phrases P: no P-phrases
Toxicological data	> 14700 mg kg −1 ( LD 50 ,  rat ,  oral ) > 2000 mg kg −1 ( LD 50 ,  rat ,  transdermal )
As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

11-aminoundecanoic acid is a longer-chain saturated amino acid with an amino group at the end . It is accessible via several chemical reaction stages from castor oil, which is unsuitable for use as food , and is therefore a monomer component for polyamide 11 that is not in competition between renewable raw materials and food .

presentation

The synthesis of 11-aminoundecanoic acid developed by the French chemical company Arkema takes place in four separate steps:

1. Transesterification of castor oil to methyl ricinoleate

Raw castor oil consists of about 90% of the triglyceride of ricinoleic acid and, by supplying a mixture with methanol in the ratio 1: 3 in a stirred reactor in the presence of basic transesterification catalyst sodium methoxide at 80 ° C within 1 h of reaction time quantitative methyl ricinoleate - the Methylester of Ricinoleic acid - implemented. At the end of the reaction, the resulting glycerine settles , the liquid methyl ester is washed with water to remove glycerine residues.

2. Pyrolysis of methyl ricinoleate to give heptanal and methyl undecenoate

Methyl ricinoleate is evaporated at 250 ° C, mixed with 600 ° C hot steam in a ratio of 1: 1 and broken down into the cleavage products heptanal and methyl undecenoate in a cracking furnace at 400-575 ° C with a residence time of approx . In this variant of steam cracking, the aliphatic chain is cleaved selectively between the hydroxymethylene and the allyl methylene group. In addition, a mixture of methyl esters of saturated and unsaturated C ₁₈ carboxylic acids falls under the name Esterol® u. a. is used as a lubricant additive.

3. Hydrolysis of the methyl undecenoate to 10-undecenoic acid

The saponification of the methyl ester with sodium hydroxide solution takes place at 25 ° C. within 30 minutes with quantitative yield. After acidification with hydrochloric acid , solid 10-undecenoic acid (undecylenic acid) is obtained.

4. Hydrobromination of 10-undecenoic acid to 11-bromundecanoic acid

The undecenoic acid is dissolved in toluene and, in the presence of the free radical starter benzoyl peroxide (BPO), gaseous hydrogen bromide is added in a radical manner contrary to the Markovnikov rule ("anti-Markovnikov"). The rapid and strongly exothermic reaction delivers 11-bromundecanoic acid in 95% yield when cooled to 0 ° C - the Markovnikov product 10-bromundecanoic acid is formed as a small by-product. The toluene and unreacted hydrogen bromide are stripped off in vacuo and recycled.

5. Bromo exchange in 11-bromundecanoic acid to 11-aminoundecanoic acid

The 11-bromundecanoic acid is mixed with a large excess of 40% aqueous ammonia solution at 30 ° C. After the reaction has ended, water is added and the mixture is heated to 100 ° C. to drive off the excess ammonia, cooled, crystallized and centrifuged.

The acid can be recrystallized from water. For further purification, the hydrochloride of 11-aminoundecanoic acid, which can be obtained by acidification with hydrochloric acid, can be recrystallized from a methanol / ethyl acetate mixture.

properties

11-aminoundecanoic acid is a white crystalline and odorless solid with low solubility in water.

use

The chloroacetylamino-11-undecanoic acid formed by acylation of 11-aminoundecanoic acid with chloroacetyl chloride acts as a fungicide and insecticide against pests.

N- acyl derivatives of 11-aminoundecanoic acid in the form of oligomeric amides have remarkable properties as gelling agents for water and organic solvents.

Monomer component for polyamide 11

By far the most important use of 11-aminoundecanoic acid is its use as a monomer component for polyamide 11 (nylon-11, Rilsan®). Wallace Hume Carothers , the inventor of the polyamide ( nylon 66 ) is said to have polymerized 11-aminoundecanoic acid as early as 1931.

Polyamide 11 is derived from a renewable raw material, i. H. bio-based, but still not biodegradable. It has the most advantageous ecological profile of comparable thermoplastics . Because of its excellent toughness at low temperatures, polyamide 11 can be used at temperatures as low as −70 ° C. Its relatively non-polar molecular structure due to the low density of amide bonds in the molecule leads to a lower moisture absorption compared to polyamide 6 and polyamide 66. In addition, polyamide 11 has very good chemical stability, e.g. B. to hydrocarbons, a low density, good thermal stability and weather resistance and is easy to process.

Individual evidence

1. ↑ ^{a b c d} data sheet 11-amino-undecanoic acid from Sigma-Aldrich , accessed on December 29, 2013 ( PDF ).
2. ↑ ^{a b} Entry on 11-aminoundecanoic acid in the GESTIS substance database of the IFA , accessed on December 29, 2013(JavaScript required) .
3. ↑ ^{a b c} GPS Safety Report: 11-aminoundecanoic acid
4. ↑ ^{a b} OECD : Screening Information Dataset (SIDS) Initial Assessment Report (SIAR) for Undecanoic acid, 11-amino- , accessed on October 28, 2014.
5. ^ A. Chauvel, G. Lefebvre, Petrochemical Processes: Technical and Economic Characteristics , Volume 2, p. 277, Editions Technip, Paris, 1989, ISBN 2-7108-0563-4
6. ↑ M.-H. Koh et al .: Divergent process for C ₁₀ , C ₁₁ , and C ₁₂ α-amino acid and α, ω-dicarboxylic acid monomers of polyamides from castor oil as a renewable resource. In: Bull. Korean Chem. Soc., 33 (6), 1873-1878 (2012), doi : 10.5012 / bkcs.2012.33.6.1873 .
7. ↑ Patent US4055663 : Halogenated acylamino acids as fungicides. Filed on June 27, 1974 , published on Oct. 25, 1977 , inventor: Sol J. Barer et al, assigned to National Patent Development Corp ...
8. ↑ A. D'Aleo et al., 11-Aminoundecanoic acid: a versatile unit for the generation of low molecular weight gelators for water and organic solvents , Chem. Commun., 2004 , 190-191, doi : 10.1039 / B307846A .
9. ↑ Renewable Polymers: Synthesis, Processing, and Technology , edited by V. Mittal, J. Wiley & Sons, Hoboken, NJ, ISBN 978-0-470-93877-5
10. ↑ Jim Mason: Rilsan Polyamide-11 - A success story for sustainable resource based engineering thermoplastics , April 9, 2008.