W-Aminoundecanoic acid

Cracking of the ester at about 500°C leads to the formation of the undecylenic acid ester together with such products as heptyl alcohol, heptanoic acid and heptaldehyde. Undecylenic acid may then be obtained by hydrolysis of the ester. Treatment of the acid by HBr in the presence of a peroxide leads to w-bromoundecanoic acid together with the 10-isomer, which is removed. Treatment of the w-bromo derivative with ammonia leads to w-aminoundecanoic acid, which has a melting point of 50°C (Figure 18.8). 

This polymer may be prepared by stirring the molten w-aminoundecanoic acid at about 220°C. The reaction may be followed by measurements of the electrical conductivity of the melt and the intrinsic viscosity of solutions in w-cresol. During condensation 0.4-0.6% of a 12-membered ring lactam may be formed by intramolecular condensation but this is not normally removed since its presence has little effect on the properties of the polymer. 

Nylon-11 is poly(w-aminoundecanoic acid). In the polymerization of w-aminoundec-anoic acid, H2N(CH2)ioCOOH, to produce this polymer, what weight fraction of the reaction mixture will have the structure -[-NH-(CH2)io-CO-]ioo- when 99% of the functional groups have reacted ... 

There is also an alternative numbering system for synthetic polyamides. Polymers that could be made from amino acids are called nylon-jc, where x is the number of carbon atoms in the repeating unit. Thus, polycaprolactam (1-13) is nylon-6, while the polymer from aminoundecanoic acid is nylon-11. Nylons from diamines and dibasic acids are designated by two numbers, in which the first represents the number of carbons in the diamine chain and the second the number of carbons in the dibasic acid. Structure 1-6 is thus nylon-6,6. Nylon-6,6 and nylon-6 differ in repeating unit length and symmetry and their physical properties are not identical. 

Nylon-11 is produced by the condensation polymerization of w-aminoundecanoic acid at 200-220°C with continuous removal of water. The latter stages of the reaction are conducted under reduced pressure to drive the polymerization to completion. 

Aminotris (methylphosphonic acid). See Aminotrimethylene phosphonic acid Aminoundecanoic acid. See 11-Aminoundecanoic acid 11-Aminoundecanoic acid CAS 2432-99-7 EINECS/ELINCS 219-417-6 Synonyms Aminoundecanoic acid u>-Aminoundecanoic acid 11-Aminoundecylic acid Undecanoic acid, 11-amino-Empihcal C11H23NO2 Formula H2N(CH2)ioCOOH Properties Wh. cryst. powd. sol. 10-50 mg/ml in 5% acetic acid (16 C) sol. < 1 mg/ml in DMSO, 95% ethanol, methanol, acetone, toluene sol. < 0.1 mg/ml in water m.w. 201.31 m.p. 190-192 C (dec.)... 

Methyl 10-undecenoate hydroborated with 1 M BH3-THF in THF at 0°, the stirred soln. allowed to reach room temp, over 1-3 h, trimethylsilyl azide added followed by methanol, then the mixture refluxed for 10 h - methyl 11-aminoundecanoate. Y 61 %. The method is especially suitable for preparing amines with acid- and/or base-sensitive functions (esters, methylenedioxy, and benzyl ethers remaining unaffected). F.e.s. G.W. Kabalka et al., Synth. Commun. 18, 1363-9 (1988). 

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