Tetraethylammonium Halides Research Articles

From a eutectic mixture to a deep eutectic system via anion selection: Glutaric acid + tetraethylammonium halides.

In pursuit of understanding structure-property relationships for the melting point depression of binary eutectic mixtures, the influence of the anion on the solid-liquid (S-L) phase behavior was explored for mixtures of glutaric acid + tetraethylammonium chloride, bromide, and iodide. A detailed experimental evaluation of the S-L phase behavior revealed that the eutectic point is shifted toward lower temperatures and higher salt contents upon decreasing the ionic radius. The salt fusion properties were experimentally inaccessible owing to thermal decomposition. The data were inter- and extrapolated using various models for the Gibbs energy of mixing fitted to the glutaric-acid rich side only, which allowed for the assessment of the eutectic point. Fitting the experimental data to a two-parameter Redlich-Kister expansion with Flory entropy, the eutectic depth could be related to the ionic radius of the anion. The anion type, and in particular its size, can therefore be viewed as an important design parameter for the liquid window of other acid and salt-based deep eutectic solvents/systems.

EFFECT OF THE QUATERNARY AMMONIUM SALTS, TETRAETHYLAMMONIUM HALIDE ON RUMEX ACETOSA L., CHENOPODIUM ALBUM L. AND GALINSOGA PARVIFLORA CAV.: INHIBITION OF GROWTH AND CHANGES IN ASSIMILATION PIGMENTS CONTENT IN PLANTS

EFFECT OF THE QUATERNARY AMMONIUM SALTS, TETRAETHYLAMMONIUM HALIDE ON RUMEX ACETOSA L., CHENOPODIUM ALBUM L. AND GALINSOGA PARVIFLORA CAV.: INHIBITION OF GROWTH AND CHANGES IN ASSIMILATION PIGMENTS CONTENT IN PLANTS

A Convenient Procedure for the Formation of Per(6-deoxy-6-halo)cyclodextrins Using the Combination of Tetraethylammonium Halide with [Et2NSF2]BF4

A convenient and efficient procedure for the regioselective halogenation of the primary alcohols of cyclodextrins using the reagent combination of tetraethylammonium halide with [Et2NSF2]BF4 is described.

Halogenation of Primary Alcohols Using a Tetraethylammonium Halide/[Et2NSF2]BF4 Combination

The halogenation of primary alcohols is presented. The use of a combination of tetraethylammonium halide and [Et(2)NSF(2)]BF(4) (XtalFluor-E) allows for chlorination and bromination reactions to proceed efficiently (up to 92% yield) with a wide range of alcohols. Iodination reactions are also possible albeit in lower yields.

Solid-Phase Halogenation of a Conducting Polymer Film via Electrochemical Polymer Reaction

The solid-phase halogenation for a conducting polymer, poly(thiophene-alt-dioctylfluorene) (PTF), was carried out by constant current electrolysis in an acetonitrile solution containing tetraethylammonium halide using the polymer film on the anode. A cyclic voltammetric analysis for PTF and potentiostatic studies disclosed the reaction mechanism for the electrochemical polymer reaction. An electrolysis of the PTF film on a transparent electrode such as indium tin oxide (ITO) was also carried out.

Spectrophotometric Study of the Interaction between Tetraethylammonium Halides and Aza-15-crown-5 with I2 and ICl in Acetonitrile Solution

The interaction between tetraethylammonium chloride (TEACl) with ICl and tetraethylammonium iodide (TEAI) and aza-15-crown-5 (A15C5) with <TEX>$I_2$</TEX> and ICl have been examined spectrophotometrically in acetonitrile solution. The results of TEACl-ICl indicate the formation of <TEX>$ICl_2$</TEX> - through equilibrium reaction. In the case of TEAI-<TEX>$I_2$</TEX> and A15C5-<TEX>$I_2$</TEX>, the equilibrium formation of <TEX>$I_3$</TEX> - is confirmed. The interaction of TEAI-ICl begins with the simultaneous production of <TEX>$I_2$</TEX> and IC<TEX>$I_2$</TEX> - (at TEAI/ICl < 0.5) as well as continues with the simultaneous consumption of <TEX>$I_2$</TEX> and formation of I<TEX>$I_3$</TEX> - (at TEAI/ICl > 0.5). Similar behavior is also observed for A15C5-ICl system. However, the changes are seen at A15C5/ICl mole ratios less and more than 0.66. Several equations have been suggested for the formation of detected species. The formation constants of various reactions were evaluated from the computer fitting of the absorbance-mole ratio data. IR spectra of A15C5 and 1:1 A15C5:ICl or A15C5:<TEX>$I_2$</TEX> complexes are compared and the effect of complexation on absorption bands is discussed.

Anionic Wormlike Micellar Fluids that Display Cloud Points: Rheology and Phase Behavior

We report our investigations into the self-assembly of sodium oleate (NaOA) in the presence of a binding salt (triethylammonium chloride, Et(3)NHCl) simple salt (potassium chloride, KCl). Both salts promote the growth of long, wormlike micelles in NaOA solutions, thereby increasing the fluid viscosity. The significant difference with the Et(3)NHCl salt is that it also modifies the phase behavior of NaOA solutions. Specifically, NaOA/Et(3)NHCl solutions display cloud points upon heating, followed by phase separation into two liquid phases. Such cloud point behavior is rarely observed in ionic surfactant systems, although it is common in nonionic surfactant solutions. Interestingly, while cloud points are not observed with KCl, the addition of KCl to NaOA/Et(3)NHCl solutions further lowers the cloud point temperature. Also, in the case of tetraethylammonium halide salt, neither a cloud point nor an increase in viscosity is observed. The clouding in the case of Et(3)NHCl is attributed to the temperature-induced aggregation of anionic micelles whose surface is covered by bound counterions.

Dialkyl Peroxides Decomposition in the Presence of Quaternary Ammonium Halides

Decomposition of dicumyl peroxide and cumyl tert-butyl peroxide was studied in the presence of tetraethylammonium halides in acetonitrile, dimethylformamide, 2-propanol, and acetic acid. The tetraethylammonium halides accelerate the decomposition of dialkyl peroxides in 2-propanol and acetic acid, but do not affect the reaction velocity in dimethylformamide and acetonitrile. The decomposition products character depends on the solvent nature.

Method for selective removal of supported platinum particles from external zeolite surfaces: characterisation of and application to a catalyst for the selective reduction of nitrogen oxide by hydrocarbons

A method for selectively removing Pt particles supported on H–ZSM-5 (Pt/H–ZSM-5) from the external surfaces of zeolite crystals was investigated, using a reagent system composed of halogen–tetraethylammonium halide–organic solvent. The influence of the nature of the halogen and the treatment time on the quantity of Pt removed was studied. After treatment of the Pt/H–ZSM-5, the characterisation by hydrogen chemisorption, XPS and TEM indicated that the method is suitable for preparing a zeolite material that contains exclusively Pt particles confined in the grain boundaries of zeolite crystals (enveloped Pt). As an example of its application, the catalytic activity for the reduction of nitrogen oxides (NO x ) with n-dodecane in the presence of oxygen was studied. The results indicate a beneficial effect of removing Pt from the outermost surface of Pt/H–ZSM-5, with an increase in the selectivity of NO x reduction to N 2 from 25 to 45% at the maximum of NO x conversion. This effect was mainly attributed to the hindered access of the bulky hydrocarbon molecules to the enveloped Pt, thus favouring the reaction of the hydrocarbon with NO 2 formed by the oxidation of NO on the Pt sites.

Synthesis and Nucleophilic Dealkylation of Poly[alkyl-(4-(phenylthio)phenyl)sulfonium trifluoromethanesulfonate

The dealkylation of sulfonium salts with nucleophiles such as halide ions takes place effectively to yield poly(phenylene sulfide). The kinetic analysis by means of UV−vis spectroscopy reveals that the dealkylation proceeds quantitatively to convert the sulfonium bond to a thioether bond. The reaction rate constants of the dealkylation by the halide ions are in the order I- > Br- > Cl-. A propyl substituent on the sulfonium salt results in a lower dealkylation rate than that with methyl substituents, because of the steric hindrance of the propyl group. The demethylation of poly[methyl-(4-(phenylthio)phenyl)sulfonium trifluoromethanesulfonate] also proceeds efficiently on soaking thin films in dichloromethane solution containing tetraethylammonium halide for 20 h and results in the formation of a transparent and amorphous poly(p-phenylene sulfide) (PPS) film, because the synthetic procedure occurs under the glass transition temperature of PPS (90 °C), although PPS is well-known to be a highly crystalline p...

NOVEL CYCLIC PENTACOORDINATE AND PSEUDOPENTACOORDINATE LEAD COMPOUNDS

Abstract The new bicyclic lead(II) phosphinate [(t-Bu)2PO2]2Pb (1) was synthesized by the reaction of p-tolyllead triacetate with di-t-butylphosphinic acid and water. An X-ray study showed that it had a pseudo-trigonal bipyramidal geometry (p-TBP) with a stereochemically active lone pair of electrons occupying an equatorial site. Infrared data ruled out the possible presence of a Pb[sbnd]H bond. A series of new monocyclic Pb(IV) compounds, [Et4N][(MeC6H3S2)PbPh2X] where X = Br (2), CI (3), and F (4), was synthesized from the addition reaction of tetraethylammonium halide to 2,2-diphenyl-1,3,2-toluene dithiolato plumbole(IV), (MeC6H3S2)PbPh2 (5). An X-ray study of 3 revealed a monocyclic anionic TBP geometry which was compared with related dithiolato cyclic structures formed earlier by lighter elements of Group IVA. The lead(II) compound 1 crystallizes in the monoclinic space group C2/c with a = 15.594(4) A, b = 16.889(3) A, c = 12.642(2) A, β = 136.85(1)°, and Z = 4. The lead(IV) compound 3 crystallizes i...

Densities in the Liquid Hydrogen Chloride Solvent System

Densities were measured in the hydrogen chloride solvent system over the normal liquid range of the solvent. In addition to pure hydrogen chloride, solutions of tetramethylammonium chloride, tetramethylammonium bromide, tetramethylammonium iodide, and trimethylsulfonium iodide in hydrogen chloride were measured at compositions up to about 2 M. Attempts to measure densities of tetraethylammonium halide solutions failed, as the salts were found to be insoluble in liquid hydrogen chloride. Solutions were prepared by condensing hydrogen chloride over solute in a graduated borosilicate glass cell. The densities were measured by a direct Archimedean technique using a fused quartz helix to indicate the weight of a submerged sinker. The accuracy of the method is 0.0006 g/cm3 with a precision of 0.0005 g/cm3. The measured densities of pure hydrogen chloride are consistent with values reported in other recent studies. The molar volume and the thermal expansion coefficient of the pure liquid are calculated. The molar volume indicates a void space of roughly 50% in the pure liquid; this finding is consistent with the view that liquid hydrogen chloride does not self-associate to any appreciable extent. The thermal expansion coefficient is on the same order of those of other room-temperature molecular liquids but is 1 order of magnitude larger than that of water. The measured densities of the electrolyte solutions are found to obey Root's equation.

Hydrogen bonding Part 54. NMR study of the effects of anesthetics on hydration of choline, acetylcholine and tetraethylammonium halides in aqueous solution

Abstract The onset and development of 14 N to CH coupling on sequential dilution of saturated solutions of the chloride and bromide salts of choline, acetylcholine and tetraethylammonium cations were used to determine the effect of the anesthetic substances chloroform, methane, argon and diethyl ether on the formation of primary and secondary hydration structures. The addition of anesthetics tends to reduce the number of H 2 O molecules required to form the primary structure. Anesthetics reduce the number of H 2 O molecules in the secondary structures of salts that form secondary structures in the absence of anesthetics, and promote the formation of secondary structures for salts that do not form secondary structures in the absence of anesthetics. These phenomena are discussed in terms of competition between salt and anesthetic substance as structure formers. Anesthetics appear to disrupt the “iceberg” water of hydration of acetylcholine; this effect might play some role in their action in anesthesia.

β Hydrogen bonding: Part 28. NMR study of β-CH to 14N coupling as a function of hydration of tetraethylammonium halides

Tetraethylammonium ion in dilute aqueous solution shows clearly resolved coupling between 14N and the β-CH of the methyl groups; this coupling is absent in the lowest liquid hydrates of the halide salts. Observation of the development of coupling as the lowest liquid hydrates are diluted suggests that the cation forms an initial clathrate with the first 6–7 mol of water, and that formation of this clathrate is independent of anion. Additional water may result in a larger, looser hydration shell; however, the formation of this second structure is anion dependent.

Thermochemical study of tetramethyl- and tetraethylammonium halides: nonionic cohesive energies in the crystals and hydration enthalpies of the cations [Erratum to document cited in CA109(18):157508p

ADVERTISEMENT RETURN TO ISSUEPREVArticleThermochemical study of tetramethyl- and tetraethylammonium halides: nonionic cohesive energies in the crystals and hydration enthalpies of the cations [Erratum to document cited in CA109(18):157508p]Yatsuhisa Nagano, Minoru Sakiyama, Tadayuki Fujiwara, and Yasuhiko KondoCite this: J. Phys. Chem. 1989, 93, 18, 6882Publication Date (Print):September 1, 1989Publication History Published online1 May 2002Published inissue 1 September 1989https://doi.org/10.1021/j100355a063RIGHTS & PERMISSIONSArticle Views27Altmetric-Citations1LEARN 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 (61 KB) Get e-Alerts

Thermochemical study of tetramethyl- and tetraethylammonium halides: nonionic cohesive energies in the crystals and hydration enthalpies of the cations

Thermochemical study of tetramethyl- and tetraethylammonium halides: nonionic cohesive energies in the crystals and hydration enthalpies of the cations

ChemInform Abstract: MOLECULAR MOTION IN SOLID TETRAETHYLAMMONIUM HALIDES

Abstract The second moments of the proton NMR lines as well as spin-lattice relaxation times, T1, for polycrystalline tetraethylammonium halides [(C2H5)4]NX, X=F−, Cl−, Br− or I− were measured from 77 to 473 K. A stepwise decrease in the temperature dependences of the second moments and minimum values of the relaxation times have been observed for all the compounds studied. The experimental results are discussed in terms of a theoretical model with consecutive onset of reorientations of the methyl and ethyl groups and cationic tumbling. The appropriate activation parameters have been determined. Reorientations of the ethyl groups around NC bonds are found to be highly correlated. The motional behaviour appears signaficantly affected by phase transitions and anion-cation interaction. The occurrence of the solid-solid phase transitions was verified by DTA.

Molecular motion in solid tetraethylammonium halides

The second moments of the proton NMR lines as well as spin-lattice relaxation times, T 1, for polycrystalline tetraethylammonium halides [(C 2H 5) 4]NX, X=F −, Cl −, Br − or I − were measured from 77 to 473 K. A stepwise decrease in the temperature dependences of the second moments and minimum values of the relaxation times have been observed for all the compounds studied. The experimental results are discussed in terms of a theoretical model with consecutive onset of reorientations of the methyl and ethyl groups and cationic tumbling. The appropriate activation parameters have been determined. Reorientations of the ethyl groups around NC bonds are found to be highly correlated. The motional behaviour appears signaficantly affected by phase transitions and anion-cation interaction. The occurrence of the solid-solid phase transitions was verified by DTA.

The conductance of tetraethylammonium salts in water-methanol mixtures

Conductance measurements are reported for tetraethylammonium halide and perchlorate salts in water-methanol mixtures over the complete composition range at 25° C. Limiting conductances and association constants are evaluated together with the distance parameters. The maxima in the limiting ionic Walden products are considered in some detail. Ionic association is generally weak, and the lack of reliable correlation betweenK A and the solvent dielectric properties supports the assumption of specific ion-solvent interaction.

Synthetic studies with carbonates. Part 6. Syntheses of 2-hydroxyethyl derivatives by reactions of ethylene carbonate with carboxylic acids or heterocycles in the presence of tetraethylammonium halides or under autocatalytic conditions

Reactions of ethylene carbonate (1a) with a variety of carboxylic acids catalysed by tetraethylammonium halides gave the corresponding 2-hydroxyethyl esters along with the diesters arising from disproportionation of the former products induced by the quaternary ammonium halides. Formation of the disproportionation products could be minimized by use of a short reaction time. The autocatalytic reactions of (1a) with strongly acidic carboxylic acids at elevated temperature gave ethylene glycol diesters selectively. Reaction mechanisms are discussed. Reactions of cyclic carbonates such as (1a) and propylene carbonate(1b) with acid anhydrides or active acyl compounds such as p-nitrophenyl acetate in the presence of tetraethylammonium iodide gave alkylene glycol diesters or 2-acyloxyalkyl aryl ethers in high yields. An attempt to extend this reaction to cyclohexane-1,2-diyl carbonate was unsuccessful, but a reaction with 1,2-epoxycyclohexane succeeded; this enabled us to examine the stereochemistry of the reaction. Finally, N-2-hydroxyethylation of a series of heterocyclic compounds having acidic imino hydrogen atoms was performed, both with tetraethylammonium iodide as catalyst and without a catalyst.