Solutions Of Quaternary Ammonium Salts Research Articles

Pretreatment of corn stover using aqueous quaternary ammonium salt solutions for improved enzymatic saccharification

Pretreatment of corn stover using aqueous quaternary ammonium salt solutions for improved enzymatic saccharification

Thermodynamic modeling of gas solubility in aqueous solutions of quaternary ammonium salts with the e-CPA equation of state

The study of gas solubility in aqueous electrolyte solutions is important, e.g. for hydrate applications, and it is also a challenging task, as metal halide salts show salting-out effects on gas in water, while some quaternary ammonium salts (QAS) show salting-in effects. This work presents a modeling study of gas solubility in aqueous solutions of several QAS (tetra-n-methyl-ammonium bromide, tetra-n-ethyl-ammonium bromide, tetra-n-propyl-ammonium bromide and tetra-n-butyl ammonium bromide) with the electrolyte Cubic-Plus-Association Equation of State (e-CPA). The ion size and ion-water interaction parameters are obtained by fitting the experimental data of mean ionic activity coefficients and osmotic coefficients of corresponding binary mixtures. The results show that e-CPA can reasonably correlate the mean ionic activity coefficients of QAS in aqueous solutions. The ion-gas interaction parameters are obtained by fitting the experimental data of gas solubility and the results show that e-CPA can correlate the gas solubilities (for nitrogen, carbon dioxide, methane and ethane) reasonably well from a quantitative point of view. For example, e-CPA gives deviations of 9.2% and 5.7% for the solubilities of carbon dioxide and methane in TBAB, respectively. The salting-in and salting-out effects and the influencing factors are also studied.

Effect of self-assembly aggregation on physical properties of non-aqueous ionogels based on LMWG

In recent years the low-molecular-weight gelators (LMWG) started to be used as a hardener for liquid electrolytes to create ionogels (OIG). The characteristic properties of gels created by LMWG, like thermal reversibility, very low critical concentration of the gelator, and huge versatility of possible compounds that can be used, were thought to give them advantage over commercial polymer gel electrolytes (PGE). However, the PGE are still dominating, mainly thanks to its superior mechanical resistance and wide temperature range when compared to OIG. The narrow temperature range of the gel phase existence in case of OIGs is the biggest disadvantage. This paper reports the interdisciplinary study on physical properties of created ionogels with nonaqueous electrolyte solutions of quaternary ammonium salts (TAMBr, TEABr, TBABr) and low-molecular-weight gelators for different molar concentrations of the electrolyte. It will be shown how the self-assembly aggregation phenomenon can be used to extend the temperature range of the ionogel phase existence. The thermal scanning conductometry (TSC) method was used to investigate the electric properties of the ionogels. To investigate the transport properties of the cations and solvent molecules in the gel and sol phase, the NMR diffusometry method was used. For identification of intermolecular interaction in studied systems, the NMR spectroscopy method was used and to study how the different salts influence on the properties of used solvent, the tuning-fork vibration viscosimetry method was used.An enhanced thermal stability effect in renewable organic ionic gels (OIGs) achieved by controlling the self-assembly process during gelation stage.

Cation-π Interactions between Quaternary Ammonium Ions and Amino Acid Aromatic Groups in Aqueous Solution.

Cation-π interactions play important roles in the stabilization of protein structures and protein-ligand complexes. They contribute to the binding of quaternary ammonium ligands (mainly RNH3+ and RN(CH3)3+) to various protein receptors and are likely involved in the blockage of potassium channels by tetramethylammonium (TMA+) and tetraethylammonium (TEA+). Polarizable molecular models are calibrated for NH4+, TMA+, and TEA+ interacting with benzene, toluene, 4-methylphenol, and 3-methylindole (representing aromatic amino acid side chains) based on the ab initio MP2(full)/6-311++G(d,p) properties of the complexes. Whereas the gas-phase affinity of the ions with a given aromatic follows the trend NH4+ > TMA+ > TEA+, molecular dynamics simulations using the polarizable models show a reverse trend in water, likely due to a contribution from the hydrophobic effect. This reversed trend follows the solubility of aromatic hydrocarbons in quaternary ammonium salt solutions, which suggests a role for cation-π interactions in the salting-in of aromatic compounds in solution. Simulations in water show that the complexes possess binding free energies ranging from -1.3 to -3.3 kcal/mol (compared to gas-phase binding energies between -8.5 and -25.0 kcal/mol). Interestingly, whereas the most stable complexes involve TEA+ (the largest ion), the most stable solvent-separated complexes involve TMA+ (the intermediate-size ion).

Phase Equilibrium of Methane Hydrate in the Presence of Aqueous Solutions of Quaternary Ammonium Salts

Families of various quaternary ammonium salts (QAS) have been of great interest to gas hydrate based investigations. In this work, an attempt has been made to understand the effect of QAS of the bromide family with increasing alkyl chain length, such as tetra-methyl, tetra-ethyl, and tetra-butyl ammonium bromide (TMAB, TEAB, and TBAB) at two different concentrations (0.05 and 0.1 mass fraction) in an aqueous solution on the hydrate–liquid–vapor (H-L-V) phase equilibrium of the methane hydrate system. Various experiments were performed to capture phase equilibrium data in the equilibrium pressure range of 7.6–4.2 MPa and temperature range of 282.4–276.8 K. It has been observed that the addition of TMAB and TEAB shifts the phase equilibrium curve of methane hydrate to higher pressure and lower temperature conditions. TMAB and TEAB have shown thermodynamic inhibition unlike TBAB which has shown a promotion effect. The Clausius–Clapeyron equation is used to calculate the enthalpy of dissociation of methane hy...

Influence of Quaternary Ammonium Salts on the Structure of Polypropylene Fibers

This paper presents the results of the study of the effects that aqueous solutions of quaternary ammonium salts have on the structure of the polypropylene fiber when heated. It has been shown that lowered melting and crystallization temperature of polypropylene after treatment is caused by a change in the amorphous structure of the polymer. Transformation of the α-phase of the crystal structure of isotactic polypropylene into the β- and γ-phases was not detected.

Electrosynthesis of poly(3-methylthiophene) films: salt effect on the electrochemical and impedance properties

We studied the electrosynthesis of poly(3-methylthiophene) films in different electrolytes, i.e. 0.1 M quaternary ammonium salt solutions in acetonitrile. The analysis of the different results enabled us to explain the role of the cations and the anions of the electrolyte (doping agents) in the electrochemical synthesis and film properties. The films obtained with tetramethylammonium hexafluorophosphate (TMAPF6) are more electroactive than those prepared using tetramethylammonium tetrafluoroborate (TMABF4). This unexpected difference of behavior is due to the difference of hygroscopic properties of the two salts. We then characterized the films by electrochemical impedance spectroscopy. This technique, used to investigate the electrochemical properties, allowed us to virtually design identical electrical-equivalent circuits for the two types of film (prepared either with TMAPF6 or with TMABF4). We noted dissimilarities in the values of the components of those equivalent circuits. The different components were separately studied and their differences were explained by the salt effects.

Modeling of Activity Coefficients of Aqueous Solutions of Quaternary Ammonium Salts with the Electrolyte-NRTL Equation

Ionic liquids (ILs) have been studied recently as potential “green” solvents because of their negligible vapor pressure. Modeling the phase behavior of such liquids with water and organic solvents and their partitioning between aqueous and organic phases is vital for an evaluation of their many potential uses. Unfortunately, phase behavior data for the popular imidazolium and pyridinium salts are still somewhat limited. However, a wealth of data exists for aqueous solutions of quaternary ammonium salts, a class of compounds that includes potentially interesting ILs. Therefore, as a first step toward modeling the phase behavior of IL solutions, we show how a conventional electrolyte model, the electrolyte nonrandom two-liquid (NRTL) model proposed by Chen et al. (AIChE J. 1982, 28, 588), can be applied to model activity coefficients of quaternary ammonium salts in water. This model requires two parameters per salt that must be fit to the experimental data. Particular attention is paid to computing these bi...

Regioselective dimerization of ferulic acid in a micellar solution.

Dehydrodimers of hydroxycinnamates play an important role in the cross-linking of plant cell walls. An aqueous solution of quaternary ammonium salts with a long aliphatic chain is known to spontaneously organize itself into micelles with the ionic part at the outer sphere. It is shown that regioisomeric ferulic acid dehydrodimers can be obtained in one step from trans-ferulic acid after attachment to these micelles and using the biomimetic peroxidase-H2O2 system. The surfactant hexadecyltrimethylammonium hydroxide yielded trans-4-(4-hydroxy-3-methoxybenzylidene)-2-(4-hydroxy-3-methoxyphenyl)-5-oxotetrahydrofuran-3-carboxylic acid (25%), (E,E)-4,4'-dihydroxy-5,5'-dimethoxy-3,3'-bicinnamic acid (21%), and trans-5-[(E)-2-carboxyvinyl]-2-(4-hydroxy-3-methoxyphenyl)-7-methoxy-2,3-dihydrobenzofuran-3-carboxylic acid (14%), whereas the surfactant tetradecyltrimethylammonium bromide gave 4-cis, 8-cis-bis(4-hydroxy-3-methoxyphenyl)-3,7-dioxabicyclo[3.3.0]octane-2,6-dione (18%) as the main product. The use of micelles appears to be not only a new way to synthesize regioisomeric ferulic acid dehydrodimers but may also help to understand the regiospecificity of dimeric hydroxycinnamate formation in vivo.

Electrochemical polymerization of N‐vinylcarbazole

AbstractThe electrolysis of N‐vinylcarbazole in the solution of quaternary ammonium salts in dichloroethane leads to polymer formation in the anolyte. The effect of monomer concentrations, current levels, and nature of supporting electrolytes on the polymerization has been investigated. The polymerization is free radical with bromide salt and cationic with perchlorate or hexachloroantimonate salt. The poly(N‐vinylcarbazole) gets oxidized at the anode and can be cycled between the oxidized and neutral states. The oxidized polymers at the electrode may exhibit electrical conductivity.

Analytical application of high-molecular quaternary ammonium salts

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.

Formation and stabilization of anionic metal complexes in concentrated aqueous quaternary ammonium salt solutions

Anionic complexes of transition metals were stabilized in aqueous solutions containing high concentrations of various short-chain quaternary ammonium salts. Compounds with longer paraffin chains were effective in much less concentrated solution. Complex ions were detected spectrophotometrically. FeCl/sub 4//sup -/, which is usually formed in concentrated HCl, was the predominant Fe(III) complex in 30 m choline chloride containing only 0.12 M HCl. A yellow transitory Tc(VII) chloro-addition intermediate, formed in the reduction of TcO/sub 4//sup -/ by concentrated HCl, was stabilized when the solution also contained 25 m choline chloride. Its spectrum, as well as the isolation of an already known Tc(VII) bipyridyl complex, is reported. Concentrated organic electrolytes also stabilized Tc(V) oxide halides against disproportionation and Tc(IV) hexahalides against hydrolysis. Halochromates of Cr(VI) were formed and stabilized in dilute acid containing quaternary ammonium salts. Their UV spectra showed the well-resolved vibronic fine structure associated with the symmetric chromium-to-oxygen charge-transfer band. It is known that these progressions are resolved in aprotic solvents, but not in aqueous acidic solution alone, and that the loss of fine structure in aqueous media is due to hydrogen bonding. The stabilization of anionic metal complexes and the resolution of vibronic structure in halochromates are probably consequencesmore » of water-structure-enforced ion paring. The present work suggests that the water molecules in immediate contact with the complex anions are more strongly hydrogen bonded to each other than to the complex. 21 references, 4 figures.« less

Viscous flow in aqueous solution of quaternary ammonium salts: high concentration range

By introducing the condition that the viscosity of solutions η → η 0, the viscosity of the solvent as the concentration of the salt N → 0, we have recast Angell's equation in the following form, ln η rel = kN/[ N o( N o  N)]. This equation has been found to represent satisfactorily the viscosity behaviour of quaternary ammonium halides in aqueous solution up to high concentration and the values of N 0, the hypothetical concentration at which the solution becomes a glass, agree with those obtained from Angell's equation. The relationship with Vand's equation of fluidity is also discussed.

Effects of microscopic and macroscopic viscosity on the rate of renaturation of DNA.

AbstractThe effect of solvent viscosity on DNA renaturation rates has been investigated as a function of temperature for a number of solvent systems. The results are all consistent with a microscopic viscosity limitation of the rate determining step. Rates of renaturation in perchlorate and quaternary ammonium salt solutions are also discussed. Increasing the macroscopic viscosity with dissolved neutral or anionic polymers increases, rather than decreases, renaturation rates due to the excluded volume of the dissolved polymers.

Reduction of α-ω dibromoalkanes on aluminium and mercury cathodes

1,3-Dibromopropane and 1,4-dibromobutane have each been reduced from non-aqueous solutions of quaternary ammonium salts on cathodes of mercury and aluminium. Product analysis and kinetic measurements have shown that reduction on mercury proceeds through adsorbed radicals whereas on aluminium products are explained in terms of free radical reactions initiated by solvated electrons. Products on mercury include solid organomercury polymer and dibutylmercury from dibromobutane and by contrast cyclopropane and propane from dibromopropane. The difference is explained in terms of the kinetic facility of formation of cyclopropane and the greater stability of the adsorbed butyl diradical relative to its propyl analogue. Products on aluminium cathodes include higher bromides and dibromides.

Reduction of α-ω dibromoalkanes on aluminium and mercury cathodes

Summary 1,3-Dibromopropane and 1,4-dibromobutane have each been reduced from non-aqueous solutions of quaternary ammonium salts on cathodes of mercury and aluminium. Product analysis and kinetic measurements have shown that reduction on mercury proceeds through adsorbed radicals whereas on aluminium products are explained in terms of free radical reactions initiated by solvated electrons. Products on mercury include solid organomercury polymer and dibutylmercury from dibromobutane and by contrast cyclopropane and propane from dibromopropane. The difference is explained in terms of the kinetic facility of formation of cyclopropane and the greater stability of the adsorbed butyl diradical relative to its propyl analogue. Products on aluminium cathodes include higher bromides and dibromides.

Thin layer direct current conductivity of benzene solutions of quaternary ammonium salts

Thin layer direct current conductivity of benzene solutions of quaternary ammonium salts

STUDY OF ANION EXCHANGE EXTRACTION OF SOME ANIONIC COMPLEXES OF IRON (III) BY ORGANIC SOLUTIONS OF QUADERIC AMMONIUM SALTS

The anion-exchange extraction of salicylate, thiosulphate and thiocyanate iron (III) complexes by solutions of quaternary ammonium salts (QAS) chlorides in organic solvents (toluene, carbon tetrachloride, ethyl acetate, isobutyl alcohol, nitrobenzene) was studied. The composition of the iron (III) anionic complexes was established by the analysis of the calibration curves E = f (pCFe (III)) constructed from iron (III) solutions against the background of various contents of thiocyanate, thiosulphate and salicylate ions and the steepness of the electrode function. As an indicator electrode was used the ion-selective electrode with a membrane, which based on a nitrobenzene solution of tetradecylammonium bromide. The solution containing of alkyldimethylbenzylammonium chloride and alkyldimethylethylbenzylammonium chloride and the corresponding organic solvent were mixed in a ratio 1: 1. An organic layer containing the QAS was selected. The anion-exchange extraction was provided in contact with aqueoses solutions of Fe(III) anionic complexes. The extraction process is estimated quantitatively using a distribution coefficient (D), the value of D is calculated taking into account the iron (III) concentration in the aqueous phase before and after extraction. The content of iron (III) in solutions is determined spectrophotometrically (λ = 440 nm). It is established that the value of the distribution coefficient depends on the permittivity (ε) of the organic solvent. In the row toluene - carbon tetrachloride - ethyl acetate - isobutyl alcohol - nitrobenzene, the permittivity increases. In the same sequence, D increases for all studied complex iron(III) ions. Moreover, a decrease in the concentration of the extracted particle leads to an insignificant decrease the value of the distribution coefficient. The composition and stability of the complex iron (III) ion have a significant effect on the extraction activity.

Acid-base reactions in concentrated aqueous quaternary ammonium salt solutions. III. Dicarboxylic acids

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAcid-base reactions in concentrated aqueous quaternary ammonium salt solutions. III. Dicarboxylic acidsJoseph Steigman, Richard De Iasi, Harvey Lilenfeld, and Donald SussmanCite this: J. Phys. Chem. 1968, 72, 4, 1132–1137Publication Date (Print):April 1, 1968Publication History Published online1 May 2002Published inissue 1 April 1968https://doi.org/10.1021/j100850a008RIGHTS & PERMISSIONSArticle Views186Altmetric-Citations9LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (696 KB) Get e-Alerts

Acid-base reactions in concentrated aqueous quaternary ammonium salt solutions. I. Strong acids and bases, carboxylic acids, amines, and phenol

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTAcid-base reactions in concentrated aqueous quaternary ammonium salt solutions. I. Strong acids and bases, carboxylic acids, amines, and phenolJoseph. Steigman and Donald. SussmanCite this: J. Am. Chem. Soc. 1967, 89, 25, 6400–6406Publication Date (Print):December 1, 1967Publication History Published online1 May 2002Published inissue 1 December 1967https://doi.org/10.1021/ja01001a002RIGHTS & PERMISSIONSArticle Views682Altmetric-Citations11LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (869 KB) Get e-Alerts Get e-Alerts