Alkyltrimethylammonium halides

As an example, take the manufacture of mesoporous silica (amorphous Si02) with uniformly sized pores. Rod-like micelles of alkyltrimethylammonium ions form in an aqueous solution of an alkyltrimethylammonium halide. The micelles have a positive electric... 

Formation of the Sic Phase in Binary Aqueous Alkyltrimethylam-monium Halide Solutions. These considerations are well illustrated by the formation of the Slc phase in aqueous alkyltrimethylammonium halide solutions (17) (Figure 7). This phase is apparently composed of Si micelles—probably on balance prolate—arranged in a primitive, cubic lattice and rotating fairly freely at the lattice points. The lattice is formed by dodecyl- and tetradecyltrimethylammonium chlorides but not by the hexadecyl or octadecyl chlorides nor by any of the corresponding bromides. This may be expressed as follows. 

A series of n-alkyltrimethylammonium halides that shows a well-resolved condis state has been described recently The results of thermal analyses on these com-... 

Iwamoto K, Ohuki Y, Sawada K, Seno N (1981) Solid-solid phase transitions of long-chain n-alkyltrimethylammonium halids. Md. CrysL liq. Cryst., 73 95... 

The produced quinone makes black complexes within the original hydroquinone very easily. As shown in Figure 4.48, when the crystals of hydroquinone and quinone are placed separately, the dark-violet crystals of the complex, which are called quinhydron, appear between the two crystalline samples. We tried to stabilize hydroquinone by making complexes with various surfactant molecules containing quaternary ammonium salts, such as alkyltrimethylammonium halides, benzyl(alkyl)dimethyl-ammonium chloride, and ethyl(hexadecyl)dimethylammonium bromide (ECDAB). After many trials, complex crystals suitable for X-ray analysis were formed with benzyl(hexadecyl)dimethylammonium chloride (BCDAC) and ECDAB, as shown in Figure 4.49. 

Graphite (hydrophobic cleavage plane) Alkyltrimethylammonium halides Ci2H25N+(CH3)3Br- Ci4H29N+(CH3)3Br- CisH33N+(CH3)3Cr, Br- Vertical monolayer [28] Parallel half-cylinders [21, 22]... 

Bion et al [122] showed that the pore diameter of periodic mesoporous phenylene-silicas could be varied from 3.2 to 3.9 nm by changing the length of the hydrocarbon chain of the alkyltrimethylammonium halide surfactant (C TMAC1/Br) with n ranging from 14 to 18, respectively. 

---