Quaternary alkylammonium

Quaternary alkylammonium salts are generally water-soluble surfactants. The sol-gel-derived anion-sensing membranes encapsulating a quaternary alkylammonium salt, especially with high contents, are easy to deteriorate due to the exudation of the cationic site from the membrane to aqueous sample phases. Moreover, another issue concerning the dispersibility of ammonium salts in sol-gel-derived membranes may happen when high... 

In many other situations of donor-acceptor solutes in aprotic solvents, such as quaternary alkylammonium salts (R4NX), a UV absorption shift to higher wavelength has proved the occurrence of simple cation-anion ion... 

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.

Physical Properties. Sulfuryl chloride [7791 -25-5], S02C12> is a colodess to light yellow liquid with a pungent odor. Physical and thermodynamic properties are listed in Table 7. Sulfuryl chloride dissolves sulfur dioxide, bromine, iodine, and ferric chloride. Various quaternary alkylammonium salts dissolve in sulfuryl chloride to produce highly conductive solutions. Sulfuryl chloride is miscible with acetic acid and ether but not with hexane (193,194). 

Long-chain quaternary alkyl-ammonium phosphates (27) Quaternary alkylammonium and alkylpyridinium mercury amido-sulfonates (28)... 

SURFACTANTS Quaternary alkylammonium halides Primary amines Non-ionic surfactants... 

Two classifications of the chemical nature of the guest molecule have been proposed. The first scheme by von Stackelberg (1956) was a combination of both size and chemical nature as discussed in Section 1.2.3. The second scheme by Jeffrey and McMullan (1967) characterized the guest molecules in one of the following four groups (1) hydrophobic compounds, (2) water-soluble acid gases, (3) water-soluble polar compounds, and (4) water-soluble ternary or quaternary alkylammonium salts. 

The most widely used sensor for chloride ions in clinical analyzers is based on an ion-exchanger, a quaternary alkylammonium chloride, dispersed in a plastic membrane. It is not an ideal sensor due to the interference of lipophilic anions (e.g., salicylates, bromides) and lip-ophylic cations (e.g., bacteriostatic agents, anesthetics) and a relatively poor selectivity towards hydrogen carbonates (bicarbonates). However, compared to charged anion- and neutral carrier-based membranes that have been tested, it is still the best-suited for automated analyzers. 

Included in this category are the high-molecular weight primary amines (Primene JMT) secondary amines (Amberhte LA-2) tertiary amines (TOA, TNOA, Alamine 336) and quaternary alkylammonium salts (Aliquat 336). 

The compound class of quaternary alkylammonium salts includes alkyltrimethyl-ammonium and dialkyldimethylammonium compounds,... 

Figure 15 Determination of the rate constants kj and kj of the transport of homologous quaternary alkylammonium bromides in a three-compartment model system. Water/n-octanol/water system (upper diagram) and time dependence of substance concentrations in the different compartments after different times t (lower diagram) (reproduced from Figures 1 and 4 of ref. [443] with permission from Editio Cantor Verlag GmbH, Aulendorf, Germany).

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. 

Quaternary alkylammonium salts, used as flow reverser additives in the separation of small anions, will fall technically into the EKC definition, since the surfactant micellization is anticipated due to the electrolyte ionic strength in which the separation is conducted vide section on small ions analysis). 

The alternative use of cationic surfactants (quaternary alkylammonium salts) is recommended to increase retention of highly hydrophilic compounds. Cationic surfactants reverses the EOF. As the cationic micelles migrate electrophoretically against the anodic EOF, an extended migration window results. An example of MEKC separation using cationic surfactants is the analysis... 

Examples of true template effects nevertheless exist and can be found, for instance, in the preparation of fault-free gmelinite and mordenite zeolites [33] by the use of quaternary alkylammonium polymers prepared by reacting l,4-diazobicyclo[2.2.2]octane (Dabco) with Br(CH2)/iBr (n = 3, 4, 5, 6 and 10), hereinafter referred to as Di -n. 

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