10373. Dodecylbetaine

Nomenclature

CAS number: 683-10-3
N-(Carboxymethyl)-N,N-dimethyl-1-dodecanaminium inner salt; n-dodecyl-N,N-dimethylglycine; N,N-dimethyldodecylbetaine; (dodecyldimethylammonio)acetate; lauryl betaine; Amphitol 20BS (Kao Chem.); Amphitol 24B (Kao Chem.).
C16H33NO2; mol wt 271.44.
C 70.80%, H 12.25%, N 5.16%, O 11.79%.

Description and references

Amphoteric surfactant. Prepn from dodecyldimethylamine and sodium chloracetate: K. Daimler, C. Platz, US 2082275 (1937 to GAF); A. H. Beckett, R. J. Woodward, J. Pharm. Pharmacol. 15, 422 (1963); from α-bromomyristic acid and trimethylamine: K. Tori, T. Nakagawa, Kolloid Z. 187, 44 (1963) DOI. Physical properties: A. Amin-Alami et al., Thermochim. Acta 122, 171 (1987) DOI; Y. Chevalier et al., Langmuir 7, 848 (1991) DOI; J. G. Weers et al., Langmuir 7, 854 (1991) DOI. Skin penetration and toxicity: G. Ridout et al., Fundam. Appl. Toxicol. 16, 41 (1991) DOI PubMed. Solubilization of phosphatidylcholine liposomes: A. de la Maza et al., Chem. Phys. Lipids 94, 71 (1998) DOI PubMed.

Chemical structure

Properties

Crystals from ethanol:ether (1:20) as monohydrate, mp 183° (Beckett, Woodward); also reported as colorless needles from acetone, mp 185° (dec). Strongly hygroscopic; characteristic bitter taste. Easily sol in water, methanol, ethanol; moderately sol in acetone; sol in benzene. Zwitterionic in slightly acid to strongly alk solns, pI ≈6.65. pKa ≈1.8. Critical micelle concentration (CMC) at 25°: 2.0 mM/kg. Surface tension (at CMC): 36.7 mN/m. Krafft point: < 0°. LD50 in male rats (mg/kg): 53 i.p.; 71 orally; 1300 dermally (Ridout).

Use

High foaming surfactant for industrial and personal care formulations; as shampoo base; as antistatic agent.