Synthesis and properties of side chain liquid crystalline ionomers containing quaternary ammonium salt groups

New thermotropic side chain liquid crystalline ionomers (LCIs), containing 4-(4-allyloxybenzyloxy)-4'-alkoxybiphenyl (IM) as mesogenic unit and allyltriethylammonium bromide (ATAB) as non-mesogenic unit, were synthesized by graft copolymerization upon polymethylhydrosiloxane. The chemical structures of the polymers were confirmed by IR spectroscopy. Differential scanning calorimetry (DSC) was used to measure the thermal properties of these polymers; the mesogenic properties were characterized by polarizing optical micrography, DSC and X-ray diffraction. The influence of the alkoxy chain length on the clearing temperatures of the ionomers is clearly shown in an odd-even effect, similar to other side chain liquid crystal polymers. The mesomorphic behaviour of the ionomers is compared with that of isomeric ionomers synthesized in previous work. The results demonstrate that the phase behaviour of the two series of isomeric ionomers is similar, but with the difference that the melting temperature of ionomers with biphenyl located at the end of the mesogen is higher than for ionomers with biphenyl located at the middle of the mesogen. The latter are more useful for smectic orientational order than the former.     

Spectrophotometric determination of aluminium with ferron and a quaternary ammonium salt

The reproducibility of the ferron method for aluminium has been greatly improved by the addition of cetyltrimethylammonium chloride (CTMAC). The improvement is attributed to reduction of the reagent blank and increased stability of Al(ferron)(3-)(3). The aluminium-ferron complex formed in the presence of CTMAC has an absorption peak at 385 nm. The interference from iron can be eliminated by application of a correction based on measurement at two wavelengths.     

Extraction-spectrophotometric determination of aluminium in river water with pyrocatechol violet and a quaternary ammonium salt

The simple removal of excess of co-extracted reagent in the solvent extraction of anionic metal complexes with a quaternary ammonium salt greatly improves the determination of aluminium with Pyrocatechol Violet (PV) and zephiramine (tetradecyldimethylbenzylammonium chloride). The exchange equilibrium constants for PV reagent and aluminium complex with four univalent anions (halides and nitrate) were determined when chloroform and 1,2-dichloroethane were used as extracting solvents. The constants were compared with those obtained with Pyrogallol Red. The method with PV and chloroform is suitable for the determination of micro-amounts of aluminium in river water. The apparent molar absorptivity of the aluminium complex in chloroform is 8.9 x 10(4) 1 mol(-1) cm(-1) at 587 nm. The limit of detection and precision achieved with the method are 3 mug l(-1) and within 4% respectively. A large excess of reagent can be used, and the ternary complex can be completely extracted over the pH range 5.5-10. Masking agents allow most interferences to be suppressed.     

Study of the formation of dye-induced premicellar aggregates and its application to the determination of quaternary ammonium surfactants

Formation of dye-induced mixed premicellar aggregates from binary surfactant solutions is proposed for the determination of alkyltrimethylammonium surfactants at the muM level. The Coomassie Brilliant Blue G (CBBG) dye, negatively charged, induces the formation of cationic surfactant aggregates at concentrations far below the cmc. The role of CBBG in the formation of premicelles was studied by using pyrene as a fluorimetric probe. Formation of CBBG-cationic surfactant aggregates of well-defined stoichiometries that depend on the total surfactant concentration added is demonstrated. Also, the influence of analytical parameters affecting the concentration at which a given aggregate is formed was studied. Linear calibrations for alkyltrimethylammonium surfactants were obtained by using different cationic surfactants as titrants; therefore, the previously derived measurement parameter for mixed micelles is applicable to premicellar aggregates as well.     

新型二茂铁甲基季铵盐离子液体的合成与表征

以二茂铁与二甲胺为原料合成了碘化二茂铁甲基季铵盐,再经复分解反应得到乙酸二茂铁甲基季铵盐离子液体;表征了离子液体的结构,测定了其熔点和溶解性.结果表明,合成的乙酸二茂铁甲基季铵盐离子化合物熔点低于100℃,是一种新型的二茂铁甲基季铵盐离子液体.     

Synthesis and antimicrobial activity of a perfluoroalkyl-containing quaternary ammonium salt

A novel perfluoroalkyl-containing quaternary ammonium salt 5 was designed and synthesized. Consequently, the antimicrobial activities of compound 5 were measured with Escherichia coli 8099 as a Gram-negative strain and Staphylococcus aureus ATCC 6538 as a Gram-positive strain. Both the minimum inhibitory concentration (MIC, the lowest concentration of compound 5 that inhibits microbial growth) values of quaternary ammonium salt 5 against Escherichia coli 8099 and Staphylococcus aureus ATCC 6538 were 7.8 μg/ml.     

Mixed ternary ion associate formation between xanthene dye, cinchona-alkaloid and quaternary ammonium ion and its application to the determination of trace amounts of quaternary ammonium salts in pharmaceuticals

Xanthene dyes such as eosin and tetraiodofluorescein form 1:2 ion associates with quaternary ammonium ions at pH 7-9; however, the development of color in the organic solvent is poor. When a quaternary ammonium salt is added in the extractable 1:2 associate formed between a xanthene dye and a cinchona-alkaloid in the neutral media, a mixed ternary ion associate (xanthene dye:cinchona-alkaloid:quaternary ammonium ion=1:1:1) is formed. Its extractability is enhanced due to the more bulky associate formation. The ion association caused by addition of cinchona-alkaloids is unique. Of the cinchona-alkaloids, quinidine and cinchonidine with tetraiodofluorescein show excellent effects on sensitivity and extractability. Eosin and tetraiodofluorescein are useful as ion association reagents in the ion associate formation. The apparent molar absorptivities are about 1×10⁵ l mol⁻¹ cm⁻¹ and the calibration range for quaternary ammonium salt is from 2.5×10⁻⁷ to 1.5×10⁻⁶ M. The proposed method is applicable to the selective and sensitive determination of cetylpyridinium chloride, berberine chloride and benzethonium chloride in pharmaceuticals.     

季铵盐插层MXene复合材料的制备及其电容脱盐性能

以MXene(Ti3C2Tx)为前驱体,采用季铵盐(TTAB、CTAB、STAB)为插层剂,制备季铵盐插层MXene复合材料.研究表明,随着季铵盐烷基碳链原子数的增加,MXene的层间距逐渐增大,复合材料的电容脱盐性能随层间距的增加而逐步提高.NaCl溶液浓度为1000 mg·L-1,工作电压为1.2V时,MXene、...     

Effect of the structure of quaternary ammonium salt radicals on the nitrite-chloride exchange

It has been shown that the NO₃⁻ and Cl⁻ ions in methylpyperidine, cetylmorpholine, quinuclidine, and triethyl quaternary ammonium salts (QAS) are characterized by approximately equal exchange constants K _Cl−^NO3− despite a significant difference in the structure of QAS. For methylpyperidine, cetylmorpholine, and triethyl salts, K _Cl−^NO3− are almost equal, which can be attributed to the special features of ethyl radicals fixed into the cycles, which occupy a smaller volume and thus reduce the effect of the length of the third substituent, so that the parameters of the closest approach become nearer.     

High-performance liquid chromatographic determination of prifinium quaternary ammonium ion in human serum and urine

A simple, sensitive method for the determination of the prifinium ion, a quaternary ammonium ion, in human serum and urine is described. The method is based on extraction of the test solution with chloroform in the presence of saturated potassium bromide solution and normal-phase high-performance liquid chromatography using aqueous methanol as the mobile phase at pH 10. To prevent the dissolution of silica from the analytical column, the mobile phase is pre-saturated with silica by using a silica saturation column. Quantitation is possible down to 0.5 ng/ml of prifinium ion using 2 ml of serum and down to 5 ng/ml using a 1 ml of urine. The coefficients of variation of the method are less than 1.3% in both serum and urine. Serum levels and urinary excretion data obtained with this method are given for three healthy volunteers who had received a 60-mg oral dose of prifinium bromide.     

Antibacterial cotton treated with N-halamine and quaternary ammonium salt

Quaternary ammonium salts and N-halamines are widely used as biocides in antimicrobial coatings, and have been extensively studied over the past two decades. In this work, 5,5-dimethyl-3-(3′-triethoxysilylpropyl)hydantoin (SPH), and 3-(trimethoxysilylpropyl) octadecyl dimethyl ammonium chloride (SPODA) were synthesized and coated onto cotton fibers using a pad-dry process (PD) and the traditional pad-dry-cure process (PDC). The coated cotton swatches were characterized by FT-IR and SEM. The quaternary ammonium salt showed a relatively lower inactivating bacteria efficacy than did the N-halamine compounds. The chlorinated swatches coated with both SPH and SPODA using the PD process could inactivate about 7 logs of the Staphylococci aureus within 5–10 min and 7 logs of Escherichia coli O157:H7 within 10–30 min, respectively. The addition of quats in N-halamine coatings improved antimicrobial activity against Gram-negative bacteria E. coli O157:H7. However, this result was not observed when the PDC process was applied in coatings because of the increasing hydrophobicity of the coated samples under high coating temperature.     

Recovery of acetaminophen from aqueous solutions using a supported liquid membrane based on a quaternary ammonium salt as ionophore

A flat sheet-supported liquid membrane (FSSLM) system, consisting of an ionic liquid, tricapryl-methylammonium chloride (Aliquat 336®) in octan-2-ol, is proposed as a means of recovering acetaminophen (Ac) from aqueous solutions; Ac is an active ingredient widely used in many pharmaceutical preparations. Several parameters which could affect the transport efficiency were examined, i.e., the strippant nature and concentration in the receiving solution, the diluent nature, carrier concentration, initial acetaminophen concentration in the feed solution, and the polymeric support type. A facilitated transport was obtained by impregnating the polymeric support with 10 vol. % of Aliquat 336® in octan-2-ol, 1 M NaOH as a receiving solution, and a feed solution of Ac dissolved in ultrapure water. The study was completed by using the FSSLM thus developed for extracting Ac from some drugs in frequent use in Tunisia (Analgan®, Doliprane®, and Fervex®).     

Chromatographic retention behaviour, modelling and separation optimisation of the quaternary ammonium salt isometamidium chloride and related compounds on a range of reversed-phase liquid chromatographic stationary phases

This paper describes the reversed-phase liquid chromatographic behaviour of the trypanocidal quaternary ammonium salt isometamidium chloride and its related compounds on a range of liquid chromatographic phases possessing alkyl and phenyl ligands on the same inert silica. In a parallel study with various extended polar selectivity phases which possessed different hydrophobic/silanophilic (hydrogen bonding) activity ratios, the chromatographic retention/selectivities of the quaternary ammonium salts was shown to be due to a co-operative mechanism between hydrophobic and silanophilic interactions. The highly aromatic and planar isometamidium compounds were found to be substantially retained on stationary phases containing aromatic functionality via strong π-π interactions. The chemometric approach of principal component analysis was used to characterise the chromatographic behaviour of the isometamidium compounds on the differing phases and to help identify the dominant retention mechanism(s). Two-dimensional (temperature/gradient) retention modelling was employed to develop and optimise a rapid liquid chromatography method for the separation of the six quaternary ammonium salts within 2.5 min which would be suitable for bioanalysis using liquid chromatography-mass spectrometry. This is the first reported systematic study of the relationship between stationary phase chemistries and retention/selectivity for a group of quaternary ammonium salts.     

三烷基季铵盐阳离子表面活性剂的合成与性能测定

用柠檬酸、十二烷基二甲基叔胺与环氧氯丙烷反应合成了柠檬酸三酯三烷基季铵盐阳离子表面活性剂。实验结果表明,在异丙醇溶剂中,反应体系在80℃,反应时间12h,产物的收率为91.5%。用红外光谱、元素分析、高效液相色谱对其结构进行了表征,通过测定其临界胶束浓度、Krafft点及泡沫性能,对产物表面活性进行了分析。     

The influence of the structure of the higher quaternary ammonium salt cation on chloride-nitrate exchange

It was found that the size of quaternary ammonium salt cations strongly influenced the log$ K_{Cl^ - }^{NO_3^ - } $ K_{Cl^ - }^{NO_3^ - } value, which was explained by the special features of ionic association in the organic phase. The use of 3,4,5-tridodecyloxybenzyltridodecylammonium nitrate as an electrode active substance could increase the selectivity of the NO₃⁻-selective electrode with respect to Cl⁻ ions.     

Ion-pair liquid chromatography--atmospheric pressure ionization mass spectrometry for the determination of quaternary ammonium herbicides

High-performance liquid chromatography coupled with atmospheric pressure ionization mass spectrometry (electrospray and atmospheric pressure chemical ionization) has been used to characterize some quaternary ammonium herbicides (quats). The separation of these compounds was carried out using ion-pair chromatography with heptafluorobutyric acid (15 mM, pH 3.3) and acetonitrile gradient elution for successful coupling to mass spectrometry. Detection limits down to 0.1-4 micrograms l-1 were obtained for spiked tap water following a preconcentration step. Good reproducibilities (day-to-day and run-to-run) were also obtained.     

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

     

Extraction-spectrophotometric determination of zinc(ii) with 4-(2-pyridylazo)-resorcinol and a quaternary ammonium salt

A simple and sélective extraction spectrophotometric determination of zinc is described. The complex [Zn(PAR)(2)](CDBA)(2), where PAR is the 4-(2-pyridylazo)resorcinol anion and CDBA is cetyldimethylbenzylammonium ion, is extracted from a solution buffered at pH 9.7 with carbonate/bicarbonate. Beer's law is obeyed over the range 0.2-1.2 ppm zinc, the molar absorptivity being 9.2 x 10(4) 1 .mole(-1).cm(-1). The precision in this range is 0.0056 ppm. Cadmium in up to a 50-fold w w ratio may be masked with diethyldithiocarbamate.