Cetyltrimethylammonium

Kekicheff P, Christenson FI K and Ninham B W 1989 Adsorption of cetyltrimethylammonium bromide to mica surface below the critical micellar concentration Colloid Surf. 40 31-41... 

Gu Y and Fluang Z 1989 Thermodynamics of hemimicellization of cetyltrimethylammonium bromide at the silica gel/water interface Colloids Surf. 40 71-6... 

In this section the influence of micelles of cetyltrimethylammonium bromide (CTAB), sodium dodecylsulfate (SDS) and dodecyl heptaoxyethylene ether (C12E7) on the Diels-Alder reaction of 5.1a-g with 5.2 in the absence of Lewis-add catalysts is described (see Scheme 5.1). Note that the dienophiles can be divided into nonionic (5.1a-e), anionic (5.If) and cationic (5.1g) species. A comparison of the effect of nonionic (C12E7), anionic (SDS) and cationic (CTAB) micelles on the rates of their reaction with 5.2 will assess of the importance of electrostatic interactions in micellar catalysis or inhibition. 

Another standard industry method for surface area is based on the adsorption of cetyltrimethylammonium bromide (CTAB) from aqueous solution. This is ASTM method D3765-85 (2). This method measures the specific surface area of carbon black exclusive of the internal area contained in micropores that are too small to admit the large CTAB molecules. Eor mbber-grade nonporous blacks the CTAB method gives excellent agreement with nitrogen surface areas. 

The new way of quantitative determination of the ascorbic acid (AC) by means of ion-pair thin layer chromatography (TLC) in organo-aqueous mobile phases containing cetyltrimethylammonium bromide (CTAB) has been alaborated. 

It was found that the effect of solvents and various surfactants Triton X-100, Twin-80, Brij-35 sodium laurylsulfate, sodium cetylsulfate, cetylpyridinium chloride, cetyltrimethylammonium bromide on the luminescence intensity is insignificant. 

Cetyltrimethylammonium bromide (cetrimonium bromide, CTAB) [57-09-0] M 364.5, m 227-235"(dec). Crystd from EtOH, EtOH/ benzene or from wet acetone after extracting twice with pet ether. Shaken with anhydrous diethyl ether, filtered and dissolved in a little hot MeOH. After cooling in the refrigerator, the ppte was filtered at room temperature and redissolved in MeOH. Anhydrous ether was added and, after warming to obtain a clear soln, it was cooled and crystalline material was filtered. [Dearden and Wooley J Phys Chem 91 2404 7957 Hakemi et al. J Am Chem Soc 91 120 1987.]... 

Cetyltrimethylammonium chloride [112-02-7] Nl 320.0. Crystd from acetone/ether mixture, EtOH/ether, or from MeOH. [Moss et al. J Am Chem Soc 109 4363 1987.]... 

Chemical Designations - Synonyms Cetyltrimethylammonium chloride solution Chemical Formula CisH33(CH3)3NCl-HjO-(CH3)aCHOH. 

Oxidation of 9-(4-pyridylvinyl)-7-methyl-2-morphohno-4//-pyrido[l, 2-a -pyrimidin-4-one with cetyltrimethylammonium permanganate in CH2CI2 at room temperature for 5 h yielded a 9-formyl derivative (01MIP9). 

Martin [25] has also shown that ammonium salts display similar behavior. [Cetyltrimethylammonium]2[ZnCl4], for example, first melts to an Sc-type liquid crystal at 70 °C and then to an S -type mesophase at 160 °C. The broad diffraction features observed in the liquid-crystalline phases are similar to those seen in the original crystal phase and show the retention on melting of some of the order originating from the initial crystal, as shown in Figure 4.1-6. 

Cetyltrimethylammonium 4-vinylbenzoate (33) forms rod-like micelles that can be stabilized by radical polymerization. The resulting structure, was observed by small-angle neutron scattering to retain its original rod-like architecture and showed enhanced thermal stability and did not dissociate upon dilution. 

Observations on the Properties of Cetyltrimethylammonium Salts of some Acidic Polysaccharides, ... 

The cycloadditions of cyclopentadiene 1 and its spiro-derivatives 109 and 110 with quinones 52, 111 and 112 (Scheme 4.20), carried out in water at 30 °C in the presence of 0.5% mol. of cetyltrimethylammonium bromide (CTAB), gave the endo adduct in about 3 h with good yield [72b]. With respect to the thermal Diels-Alder reaction, the great reaction rate enhancement in micellar medium (Scheme 4.20) can be ascribed to the increased concentration of the reactants in the micellar pseudophase where they are also more ordered. 

Figure 5. Hexagonal array of cylindrical micelles of cetyltrimethylammonium in MCM-41 synthesis...

Cyclooctatrienyl Cyclopentadienyl Camphorsulfonic acid Cetyltrimethylammonium bromide... 

S,3R-(+)-4-dimethylamino-1,2-diphenyl-3-methylbutan-2-ol 1,5-Cyclooctadienyl 1,3 5-cyclooctatrienyl Cyclopentadienyl Camphorsulfonic acid cetyltrimethylammonium bromide... 

Peculiar DNA architecture was demonstrated in 25% aqueous ethanol when DNA was complexed with series of cationic detergents in the presence of poly(glutamic acid) [124]. Electron microscopy and x-ray scattering demonstrated that DNA can pack cetyltrimethylammonium bromide molecules into rodlike micelles, which form a hexagonal lattice. Interestingly, circular dichroism spectroscopy revealed that in these complexes DNA adopts left-handed conformation. 

Fig. 10.8 A where the R substituents are alkyl or heterocyclic radicals to give compounds such as cetyltrimethylammonium bromide (cetrimide), cetylpyridinium chloride and benzalkonium chloride. Inspection of the stmctures of these compounds (Fig. 10.8B) indicates the requirement for good antimicrobial activily of having a chain length in the range Cg to Cig in at least one of the R substituents. In the pyridinium compounds (Fig. 10.8C) three of the four covalent links may be satisfied by the nitrogen in a pyridine ring. Polymeric quaternary ammonium salts such as polyquatemium 1 are finding increasing use as preservatives.

---