Dimethyldodecylamine, oxidation

Amine oxides show either nonionic or cationic behavior in aqueous solution depending on pH. In acid solution the cationic form (R2N" OH) is observed (2) while in neutral and alkaline solution the nonionic form predorninates as the hydrate R NO H2O. The formation of an ionic species in the acidic pH range stabilizes the form generated by the most studied commercial amine oxide, dimethyldodecylamine oxide (6). 

The silicon precursor and N, N-dimethyldodecylamine oxide exhibit different electronic properties under different pH conditions, thus the driving forces and the corresponding sample structure may be different in various pH values. We performed the synthesis process at pH<0, pH=2, pH=7, and pH>10, respectively. The silicon precursor did not condense when pH<0. Figure 2 illustrates the Figure 1. TEM image of calcined LZC... 

To provide a specific example, Imae and Ikeda (ref. 479) state that amine oxide is very hydrophilic and can constitute a good polar head group for nonionic surfactants at neutral pH. Dimethyl-dodecylamine oxide was first prepared by Hoh et al. (ref. 494), and its surface-active properties in aqueous solutions were investigated by measurements of surface tension (ref. 495), light scattering (ref. 496-498), and hydrodynamic properties (ref. 499). It was found that dimethyldodecylamine oxide can form only spherical micelles in water and aqueous NaCl solutions, when the micelle concentration is dilute (ref. 496,498). Similarly, the homolog dimethyltetradecylamine oxide forms only spherical micelles in water (ref. 496). 

S. Ikeda, M. Tsunoda and H. Maeda, Effects of ionization on micelle size of dimethyldodecylamine oxide, J. Colloid Interface Sci. 70 (1979) 448-455. 

Figure 2. IR spectrum of solid dimethyldodecylamine oxide (C12AO) at 25 C.

The most effective additives for increasing the stability of the foam produced by surfactant solutions appear to be long-chain, often water-insoluble, polar compounds with straight-chain hydrocarbon groups of approximately the same length as the hydrophobic group of the surfactant. Examples are lauryl alcohol for use with sodium dodecyl sulfate, Af,/V-bis(hydroxyethyl) lauramide for use with dodecylbenzenesulfonate, lauric acid for use with potassium laurate, and N,N-dimethyldodecylamine oxide for use with dodecylbenzenesulfonate and other anionics. 

N.N-Dimethyldodecylamine oxide, 456 16a,17a-(DimethyIenedioxy)-A1-, i-pregna-triene-3,20-dione, 172 Dimethylethynylcarbinyl chloride, 465... 

K.W. Herrmann, Non-ionic-cationic micellar properties of dimethyldodecylamine oxide, J. Am. Chem. Soc., 1962, 66, 2895-300 P. Holt and B. Tamami, Relation between pH and viscosity of some poly(alkylvinylpyridine N-oxides) in aqueous solution, Die Makromol. Chem., 1972, 155, 55-60 L. Chmurzynski, A. Liwo and P. Barczynski, A potentiometric study of acid-base equilibria of substituted TV-oxides in nitrobenzene, Anal. Chim. Acta, 1996, 335, 147. 

Table IV except in the dimethyldodecylamine oxide (DC12AO) system. The line widths of this system are shown in Figure 14. Around 60°C. the middle phase width becomes greater than the neat phase width. The abrupt changes in the two widths occur at the mesomorphic-isotropic tran-...

Dimethyl disulfide (2,(9-Dimethyl dithiophosphate A/,A/-Dimethyldodecylamine oxide... 

The effect of added inoiganic salts on the micellar properties of the nonionic and cationic forms of dimethyldodecylamine oxide has been determined (2). 

The fundamental property of a surface active agent, as mentioned before, is that it contains both polar and nonpolar moieties in its structure. This property is termed amphiphilicity or amphipathicity, and the substances that possess it are called amphiphiles. An amphiphile can be anionic or cationic, depending on whether its hydrophobic moiety is an anion or a cation. A zwitterion is an ion that possesses both anionic and cationic groups on the hydrophobic moiety and can behave either as an anionic, cationic or neutral species. An example of an ionic type is sodium dodecyl sulfate a cationic dodecyltrimethylammonium bromide a zwitterionic A-dodecyl-3-aminopropionic acid and a nonionic N, AT-dimethyldodecylamine oxide. 

Dimethyidiphenyl siloxanes and silicones. See Phenylmethyl polysiloxane Dimethyidithiocarbamate zinc salt. See Zinc dimethyidithiocarbamate N,N-Dimethyl-1-dodecanamine-N-oxide Dimethyldodecylamine-N-oxide N,N-Dimethyldodecylamine oxide N,N-Dimethyldodecylamine-N-ox-ide. See Lauramine oxide... 

The zwitterionic surfactant IVA -dimethyldodecylamine oxide (C12DMAO) form lyotropic mesophases with La(N03)3-6H20 in water-decanol mixtures (Selivanova et al., 2010b). Different mesophases (hexagonal, lamellar, nematic) are formed depending on the molar ratio between the surfactant... 

DimethyIdodecylamine-N-oxide N,N-Dimethyldodecylamine oxide N,N-Dimethyldodecylamine-N-oxide. See Lauramine oxide... 

---