N-Alkylammonium chloride

Similarly, N-alkylammonium [28] and alkylphosphonium [29] salts form lamellar phases with smectic bilayer structures. In both cases. X-ray scattering also showed the isotropic liquid not to be completely disordered and still displaying similar features to the mesophase. Buscio et al. [28] showed that in N-alkylammonium chlorides the feature was not only much broader than that observed in the mesophase but increased in width with decreasing chain length. 

Figure 10-2. Long spacings of n-alkylammonium chlorides in all five polymorphic forms observed at room temperature...

Table 5.7. Transition temperatures and entropies for n-alkylammonium chlorides jNHj Cl"...

Busico V, Cemkxia P, Corradini P, Vacatello M (1983) Polymorphism in anhydrous and amphilic systems. Long-chain primary n-alkylammonium chlorides. J. Phys. Chem., 87 1631... 

Three-component formation was observed for pyrene- and naphtha-lene-/9-CD complexes in the presence of surfactants such as n-alkyl sulfates (chain length C4-C12), n-alkylammonium chlorides (Cj-Cg), and n-al-kyltrimethylammonium bromides (CiQ-Cig) [118]. The two complexes exhibit different behavior in the presence of surfactants. With respect to the value of the two-component system, increased association constants were found for pyrene (short-chain surfactants gave higher constants than long-chain). Lower association constants were found for / -CD-naph-thalene in the presence of surfactants. By following the time course of T-T absorption of the two aromatics in the presence of nitrite, it was found that their different behaviors were due to surfactant influence on the rate constants of formation (k+) and dissociation (k ) of the inclusion compound. For naphthalene, a reduction of k+ was observed in the presence of surfactants while k was unaffected. For pyrene, short-alkyl-... 

Surfactants n-alkylammonium-chloride, n-aUtylpyridi-nium-chloride, sodium-dodecylsulphate (Flu AG, FRG, purum). 

Investigation of the mechanism of these reactions has suggested ways in which the yields can be improved. Acidic conditions (pH 2) will prevent Cannizzaro rearrangement of any glyoxal-type species and also serve to hydrolyse any Schiff bases which result from side reactions of aldehyde and amine. Conditions should be adjusted so that the rate of hydrolysis of linear products is equal to the rate of cyclocondensation, allowing accumulation of the imidazole products. From glyoxal, formaldehyde and ammonium chloride the yield of imidazole can be inereased to 85% by careful control of the conditions. With an appropriate alkylammonium chloride, 1-substituted imidazoles are also accessible (e.g. 1-methyl (56%), 1-isopropyl (46%), 1-cyclohexyl (49%), 1-n-butyl (55%), 1-t-butyl (25%)). The process may have some applications, but yields drop off with branched alkyl compounds [22 j. Imidazolium salts are also available under similar conditions when two molar equivalents of a primary alkylamine are used [23]. 

Alkylammonium chloride n=2,4,6. Recrystallise them from EtOH or an EtOH/Et20 mixture. 

Empirical Equations Many investigators have developed empirical equations relating the CMC to the various structural units in surface-active agents. Thus, for homologous straight-chain ionic surfactants (soaps, alkanesulfonates, alkyl sulfates, alkylammonium chlorides, alkyltrimethylammonium bromides) in aqueous medium, a relation between the CMC and the number of carbon atoms N in the hydrophobic chain was found (Klevens, 1953) in the form... 

Many empirical equations have been developed relating CMC of surfactants to structural units in them. For homologous straight-chain ionic surfactants (soaps, alkylsul-fonates, alkylsulfates, alkylammonium chlorides and alkyltrimethyl-ammonium bromides) in aqueous medium, the following relationship between CMC and the number of carbon atoms (n) in the hydrophobic chain has been obtained (Somasundaran, 1964 Lin, 1971 Somasundaran and Fuerstenau, 1968 Bolden et al., 1983) ... 

A study of the structural properties of primary n-alkylammonium haUdes enabled us to evaluate the relative importance of intermolecular forces of the two types as the polar ends of the layers form strong hydrogen-bonded networks that dominate the packing on crystallization. Here we illustrate trends in the crystal chemistry of the n-alkylammonium halides, and the investigative methods, using as examples n-octadecylammonium chloride, CigH37NH Cl , and their related bromides and iodides... 

Materials. The methylammonium Y-zeolites (Table I) were prepared by ion-exchanging NaY (5 grams) with 4 100-ml portions of 1 N alkylammonium salt solution at 80 °C. Monomethylammonium (MMA) chloride, dimethylammonium (DMA) chloride, and tetramethylammonium (TTMA) bromide (Matheson, Coleman, and Bell) and the trimethyl-ammonium (TMA) chloride (Eastman Organic Chemicals) were used as received. 

Na (K) -alkyl 1-sulfates or -sulfonates Na -alkane-1-sulfonates Na -alkane-l-sulfonates Na -alkane-l-sulfonates Na n-alkyl-1-sulfates Na -alkyl-l-sulfates Na n-alkyl-2-sulfates Na p- -alkylbenzene sulfonates Na p- -alkylbenzene sulfonates /i-Alkylammonium chlorides /i-Alkylammonium chlorides /i-Alkytrimethylammonium bromides /i-Alkyltrimethylammonium chlorides (in 0.1 M NaCl)... 

Retention of solutes and selectivity can be controlled by adjusting the type and concentration of the ion-pair reagent added and by selection of the type and concentration of the organic solvent in the mobile phase (135,168). The ion pair reagents most commonly used are tetra-alkylammonium salts such as cetrimide (155,156,177) and tetra-n-butylammonium (TBA). The TBA reagent can be used as TBA phosphate (159,184), TBA chloride (221), TBA hydrogen sulfate (188,189), or TBA hydroxide (168,175,183). 

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