Alkylammonium compounds

Fig. 2.3.3. Chromatogram of quaternary alkylammonium compounds. Columna, Shodex Asahipak GF-310 HQ (100 X 4.6 mm2) mobile-phase, 0.4 mM 4,4 bipyridyl, 0.8 mM HC1, 27% (m/v) acetonitrile flow rate 0.6 ml min-1 analyte concentration 1.0 p.M injection loop, 50 p.L. Reprinted with permission from Ref. [56] 1999 Elsevier.

In connection with this mechanism, it has been reported that the reaction between elemental S and Sn in alkylammonium compounds or amines under hydrothermal conditions gives various organic tin-suphide species and even, under some conditions (low pH), SnSi [105], A possible mechanism for this process was proposed based on nucleophilic attack of the basic amine or hydroxide on the Ss chain ... 

The dichalcogenides of group VI do not readily form intercalates with organic molecules. But n-alkylammonium compounds can be prepared by ion-exchange reactions of the hydrated sodium intercalation compounds such as Na j(H20)o g M0S2. Alkylammonium compounds prepared by this route show lattice expansions that depend on the alkyl chain length, very similar to the MX2-n-alkylamine systems described above. This raises the fundamental question whether protonated amines are the actual intercalated species in both the cases, involving reduction of the host. In fact, this constitutes the basis of the new model for the intercalation reaction in MX2 proposed by Schollhorn (1980). 

Linfield, W.M. 1970. Straight chain alkylammonium compounds. In E. Jungermann, ed., Cationic Surfactants, Surfactant Science Series, Vol. 4, pp 9-70. Marcel Dekker, New York. 

Currently, the most promising biocides for potential new wood preservatives are the alkylammonium compounds (AAC). These compounds have been subjected to extensive studies (5, 6) and the di-alkyldimethylammonium compounds are suggested to be the best (7). Didecyldimethylammonium chloride 5 appears to be particularly effective. 

Cyclic alkylammonium compounds resemble the linear products in their properties. They are widely found in antiseptic solutions, cremes, shampoos, and mouthwashes. As an example for this class of compounds, Fig. 5-48 displays the chromatogram of a dodecylpyridinium chloride. Its individual components, with the exception of the main component, exhibit a similar retention behavior to that of Benzalkon A. The minor components of this sample are presumably tetradecyl- and hexadecylpyridinium chloride. 

In the same way l-decyl-3-methyHmidazolium chloride (2, [DMIM] [Cl]) and a patented plant growth regulator 4 are depicted side by side. A third example showing the structural similarity of some ILs to already existing chemicals are the quaternary alkylammonium compounds (quats) (3 versus 6). Some crystalline quats like dodecyltrimethylammonium bromide are commonly being used for disinfection or as preservatives, while tetrabutylammonium salts are easily accessible ILs. 

Crown ethers, especially 18-crown-6 ethers, can complex not only inorganic cations but also alkylammonium compounds. The primary interactions occur between the hydrogens of the ammonium group and the oxygens of the crown ether. The introduction of bulky groups such as binaphtyl onto the exterior of the crown ether provides steric barriers and induces enantioselective interactions with the guest molecule. 

Basic extractants normally consist of alkylammonium species, although for analytical applications organophosphonium or organoarsonium compounds may be used. Quaternary ammonium species as shown in Equation 1.2 or uncharged alkylammonium compounds may be used as extractants. In the latter case the presence of excess anions in the systan allows the formation of charged species as, for example. Equation 1.6 ... 

Much higher amounts of organic solvents are required for the elution of tetra-alkylammonium compounds, which are used as reagents in ion-pair chromatography of anions. If the analysis times are kept constant, an amount of 60 mL/ L acetonitrile suffices to elute tetramethylammonium hydroxide at a hexanesulfonic acid concentration of c = 1 mmol/L (Fig. 6-29), 280 mL/L is needed for the elution of tetrapropylammonium ions, and 480 mL/L for the even more... 

The presence of metal species in the montmorillonite structure may catalytically enable the oxidative cleavage of alkene substituents in alkylammonium compounds to produce aldehydes at elevated temperatures [15, 18]. 

On the other hand, clays modified with salts of aromatic amines, in which the N atom is directly linked to aromatic ring, exhibited higher thermal stability then those modified with alkylammonium compounds [117, 118]. The use of a combination of aromatic and aliphatic ammonium compounds was an effective strategy for synthesis of clays with sufficient thermal stability for thermoset polyimide resin (PI) [117]. In that case, the aromatic component of OLS provided higher thermal stability and the aliphatic component promoted intercalation. The benefits of combining aromatic and aliphatic surfactants to treat clay are also reported by other authors [ 119]. It was shown that clay treated with a 1 1 molar mixture of methylene dianihne (MDA) and dodecylamine resulted in an improvement in thermooxidative stability of Pl-based nanocomposites. 

Among the alkylammonium compounds, the tertiary amines are by far the most important actinide extractants, as has already been mentioned (Section 21.5.1). Extraction depends upon the nature and concentration of the anion in much the same manner as for neutral extractants (Section 21.5.2). A good example is the extraction of neptunyl(vi) by methyldioctylamine in chloroform from solutions containing increasing concentrations of sulfuric, hydrochloric, or nitric adds (Fig. 21.9) [178]. The value of D increases rapidly at low concentrations, and most rapidly for sulfuric add, as the complexes formed by the sulfate ion are much stronger than those formed by chloride or nitrate. Consequently, extractable... 

Average molecular weight Distribution of mono-, di-, and tri-alkylammonium compounds Alkyl chain length distribution Acid value Amine value pH... 

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