Electrochemical recognition of analytes using quaternary ammonium binaphthyl salts

The electrooxidation of quaternary ammonium binaphthyl salts is shown to proceed by a quasi-reversible one-electron process. The oxidation of an aza-crown ether substituted binaphthyl salt is affected by the presence of lithium and sodium ions in solution and there is shown to be a linear relationship between the limiting current for the process and the concentration of Li+ and Na+. The electrochemistry of the binaphthyl salt is also shown to be affected by the addition of organic cations to the solution, showing that these receptors could form the basis of analytical devices which could be made specific to a range of analytes.     

The adsorption of quaternary ammonium salts at a mercury solution interface: Part II. Non-symmetrical quaternary ammonium salts

The adsorption of triethyl alkyl (and allyl) ammonium bromides on a mercury electrode has been investigated. The isotherms and values of the free energy of adsorption yield information on the mode of adsorption of the cations. The formation of partial bimolecular films on the surface of mercury by the cations studied has been described and a simple explanation put forward concerning the mechanism of destruction of these films.     

Microwave synthesis of quaternary ammonium salts

The microwave synthesis of several quaternary ammonium salts is described. The synthesis provides comparable or better yields than published methods with reduced reaction times and in the absence of solvent.     

The synthesis of quaternary ammonium salts from ammonium salts and dialkyl carbonate

Quaternary ammonium salts were synthesized from ammonium salts and dialkyl carbonates over an ionic liquid catalyst 1-ethyl-3-methylimidazolium bromide.     

Analytical application of high-molecular quaternary ammonium salts

Summary The anion-exchange extraction of a great number of mineral, organic and metal complex anions by solutions of quaternary ammonium-salts (QAS) in different solvents, including intermediate exchange with acidic dye anions, has been investigated. Extraction-photometric methods and ion-selective electrodes for the determination of organic and metal complex anions have been developed. Simple methods for synthesis and purification of QAS are described and their self-association has been investigated by electroconductivity and interphase distribution.

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Analytische Anwendung von hochmolekularen quaternären Ammoniumsalzen

     

Photopolymerization of vinyl monomers with quaternary ammonium salts

Photopolymerization of vinyl monomers with a series of quaternary ammonium salts has been investigated. However, quaternary ammonium salts used are not photosensitizers but rather photoinitiators. The salts photoinitiation activity was observed to vary widely with the counteranion in quaternary salts used and also with the alkyl group in their amine components. In general, the halide salts were more effective than tetrafluoroborate salts. It was also found that the overall activation energy for the photopolymerization of methyl methacrylate with dimethylbenzylanilinium tetrafluoroborate was 5.9 kcal/mole, and its rate was proportional to the 0.32 and 1.0 order of the concentration of the salt and the monomer used, respectively. An endgroup similar to dimethylaniline was found to be present in the methyl methacrylate polymer obtained by above system; this is probably a methylanilinomethyl group, from the characteristics of its ultraviolet spectrum.     

Analysis of organic quaternary ammonium salts by LAMMA

Summary The application of the laser microprobe mass analyser (LAMMA) to several acyclic quaternary ammonium salts with aliphatic and aromatic substituents was investigated. The LAMMA spectra share some typical features with the ones, obtained by mass spectrometric (MS) analysis using soft ionisation techniques, e. g. the intact cations are detected as well as the iminium ions, issued from their decomposition. However, as a result of the abundant fragmentation and because of the presence of additional characteristic peaks, LAMMA spectra become largely comparable to the ones, recorded on a conventional MS with electron impact-ionisation and sample introduction by direct probe, though it is well known that the latter method induces thermal degradation of these salts and consequently only allows for the detection of the corresponding decomposition products.

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Analyse organischer quarternärer Ammoniumsalze mittels LAMMA

Zusammenfassung Die Anwendung des Laser-Mikrosonden-Massen-Analysators (LAMMA) zur Charakterisierung verschiedener acyklischer quarternärer Ammonium-salze mit aliphatischen und aromatischen Substituenten wurde untersucht. Die LAMMA-Spektren zeigen charakteristische Merkmale jener Spektren, die durch weiche Ionisierungstechniken in der Massenspektrometrie erhalten werden: z. B. werden intakte Kationen sowie Imin-Ionen detektiert. Als Folge der weitgehenden Fragmentierung und wegen zahlreicher zusätzlicher Peaks sind LAMMA-Spektren jenen Spektren sehr ähnlich, die durch Elektronenstoß-Ionisation und Direkteinführung der Probe erzeugt werden. Allerdings ist bekannt, daß die letztere Methode einen starken Abbau von Salzen bewirkt und daher nur den Nachweis von Zerfallsprodukten zuläßt.

     

离子对分离和抑制电导检测法测定四乙基铵和四丁基铵根离子

建立了季铵盐的离子色谱分析方法.采用Dionex DX-500 型离子色谱仪,C18柱,电导检测器,以30%乙腈和10 mmol/L甲烷磺酸混合溶液为流动相,流量为1.00 mL/min.四乙基溴化铵和四丁基溴化铵的质量浓度和峰面积的相关系数分别为0.9996和0.9994;线性范围分别为10～80 mg/L和20～120 mg/L;检出限分别为0.28和0.76 mg/L;RSD分别为1.3%、 2.5%.该方法可用于分析水溶液中季铵盐的含量.     

Liquid-membrane dicyanoargentate-sensitive electrodes based on quaternary ammonium salts

Several quaternary ammonium salts have been synthesized and comparisons made of their efficiency as exchange substrates in dicyanoargentate-sensitive electrodes. The electrode prepared from hexadecyltrioctylammonium dicyanoargentate shows the best performance characteristics and has been studied in more detail. Its Nernstian response range is 10(-1)-10(-4)M, the optimum pH range is 10.6-12.6, and the detection limit is 3 x 10(-5)M. It is suggested that the detection limit of the electrode is controlled by interference from cyanide ions, and the difference between detection limits obtained with the various electrodes is discussed in the light of this. Selectivity coefficients for various interfering ions have been determined and related to the extractability of the ions. The electrode has been applied to determination of silver in cyanide-containing plating solutions.     

Enantioselective alkylation of beta-keto esters by phase-transfer catalysis using chiral quaternary ammonium salts

Catalytic enantioselective alkylation promoted by a quaternary ammonium salt from cinchonine as a phase transfer catalyst is described. Treatment of cyclo beta-keto esters with alkyl halide under mild reaction conditions afforded the corresponding alpha-alkylated beta-keto esters in moderate to excellent yields with high enantiomeric excesses     

Synthesis of quaternary ammonium salts containing a polyprenyl substituent

Quaternization of triethylamine, 4-dimethylaminopyridine, and N-methylimidazole with moraprenyl bromide gives the corresponding quaternary ammonium salts.     

Catalytic enantioselective fluorination of beta-keto esters by phase-transfer catalysis using chiral quaternary ammonium salts

[reaction: see text] The catalytic enantioselective electrophilic fluorination promoted by quaternary ammonium salt from cinchonine as a phase-transfer catalyst is described. Treatment of beta-keto esters with N-fluorobenzenesulfonimide as the fluorine source under mild reaction conditions afforded the corresponding alpha-fluoro beta-keto esters in exellent yields with good to moderate enantiomeric excesses     

Simultaneous determination of bromide and iodide ions by capillary isotachophoresis using quaternary ammonium salts

Bromide and iodide ions were determined simultaneously by capillary isotachophoresis using an aqueous electrolyte system; the separation principle was based on the ion-pairing equilibria between tetradecyldimethylbenzylammonium ion and these anions in the leading electrolyte. The interaction between iodide ion and tetradecyldimethylbenzylammonium ion was stronger than that for bromide ion. Thus complete separation of bromide and iodide ions could be obtained by using a leading electrolyte containing 1.5 mM tetradecyldimethylbenzylammonium ion. The pH of the leading electrolyte was adjusted to 5.0. The relative standard deviations of the zone length for bromide and iodide ions were 1.1 and 1.2%, respectively, when mixture of 3.0 mM of these ions was analysed. A 150-μl volume could be injected for the simultaneous determination of low concentrations of bromide and iodide ions.