К 85-ЛЕТИЮ ЛЮДМИЛЫ ИВАНОВНЫ ВОРОНЧИХИНОЙ О.Е.Журавлев

This article presents the results of studying non-conducting biological, crystalline objects, powders, and glass composite samples using an ionic liquid by scanning electron microscopy. Ionic liquids based on alkylpyridinium dicyanamides studied in the work were obtained by a metathesis reaction. A solution of ionic liquid in acetone was used as a conductive coating for dielectrics. It was found that the use of ionic liquid is an alternative to the methods of metal and carbon sputtering on dielectric samples. Scanning electron microscopy images of samples obtained by such microscopy methods as low vacuum mode, the use of metal sputtering (Pt) on samples, and a study of samples without a conductive coating are presented. A comparative analysis of the results obtained by traditional methods and the method of applying ionic liquid to samples is carried out. It is shown that the use of electrically conductive ionic liquids with the thermal and chemical stability makes it possible to obtain high-resolution electron microscopic images and also allows visualization of the topographic and compositional contrast of the studied dielectric samples.

New ammonium ionic liquids with a ferrocenylmethyl radical in the cation with different long hydrophobic chains (C7H15, C12H25, and C16H33) were prepared. The thermal stability of the compounds in air in the temperature range 20–500°C was studied in comparison with an ionic liquid with the benzyl radical in the cation. A higher thermal stability of dimethylferrocenylmethylalkylammonium chlorides was shown in comparison with benzalkonium.

Синтезированы ионные жидкости ± соединения четвертичного аммония с органическими анионами (CHCOO,ClCHCOO,CClCOO) и изучены их свойства. Установлено, что ионные жидкости с органическим анионом обладают пониженной термостабильностью по сравнению с ионными жидкостями с неорганическим анионом. Ионные жидкости с длинноцепочечным радикалом принадлежат к классу катионных поверхностно-активных веществ и снижают поверхностное натяжение воды в пределах (50-32 мН/м) Ionic liquids ± compounds of quaternary ammonium with organic anions (CHCOO,ClCHCOO ,CClCOO) were synthesized and their properties were studied. It is established that ionic liquids with an organic anion have reduced thermal stability compared to ionic liquids with an inorganic anion. Ionic liquids with a long-chain radical belong to the class of cationic surfactants and reduce the surface tension of water within (50-32 mN/m).

The electrical conductivity of a number of tetraalkylammonium ionic liquids with tetrafluoroborate anion has been studied in acetone in the temperature range 298–313 K. Based on the obtained conductometric data for the compounds under study, the Lee–Wheaton method has been used to calculate the ion association constants ( K a ), limiting molar electrical conductivities (λ 0 ), and Gibbs association energy (Δ G 0 ) in solutions. From the temperature dependence of equivalent electrical conductivity, the values of association enthalpy (Δ H 0 ) and entropy (Δ S 0 ) have been calculated. For all studied compounds, the Walden–Pisarzhevsky product has been calculated. Conclusions are drawn about the influence of the structure of the studied ionic liquids on the thermodynamic parameters of association in acetone solutions.

A study is performed of the electrical conductivity (EC) of ionic liquids based on quaternary triethylalkylammonium salts with tetrafluoroborate and hexafluorophosphate anions in acetonitrile. Conductometric data on these compounds are analyzed. Constants Ka of the ionic association of the limiting molar electrical conductivity (λ0) and the standard Gibbs energy of association (ΔG0) in solutions are calculated using the Lee–Wheaton formula. The Stokes radii, limiting mobility, and limiting coefficients of diffusion are found for tetraalkylammonium cations.

ТЕРМИЧЕСКАЯ СТАБИЛЬНОСТЬ АММОНИЕВЫХ ИОННЫХ ЖИДКОСТЕЙ С ФЕРРОЦЕНИЛМЕТИЛЬНЫМ РАДИКАЛОМВ КАТИОНЕ Л

ЭЛЕКТРОПРОВОДНОСТЬ РАСТВОРОВ АММОНИЕВЫХ ИОННЫХ ЖИДКОСТЕЙ С МЕТАЛЛАТНЫМИ АНИОНАМИ В АЦЕТОНЕ

Thermal stability of N-alkylpyridinium tetrachloroferrates(III) [C5H5NR]FeCl4 [R = C4H9, (CH2)3CN, CH2C6H5, C8H17, and C10H21] in air in the range of 25–600°C has been studied, as well as the thermal stability of N-alkylpyridinium chlorides. The equivalent electrical conductivity of N-alkylpyridinium tetrachloroferrates(III) in acetonitrile solution at 25°C has been investigated. The ionic association constants Ka, the limiting molar electrical conductivity (λ0), and the standard Gibbs energy of the association (ΔG°) in the acetonitrile solutions have been calculated based on conductometric data via the Lee–Wheaton method.

Zinc sulfide nanoparticles (quantum dots) were synthesized from aqueous solutions of sodium sulfide and zinc sulfate using pyridinium ionic liquids. The average size of zinc sulfide nanoparticles was determined by UV spectroscopy, X-ray diffraction, and scanning electron microscopy. The influence of the structure and concentration of pyridinium ionic liquids with the tetrafluoroborate anions on the size of zinc sulfide nanoparticles was studied. The effect of the precursor concentration on the size of the nanoparticles formed in the ash was established.

Bis-Quaternary ammonium ionic liquids―triethylamine derivatives with hexafluorophosphate, tetrafluoroborate, and dicyanamide anions―were synthesized in the study. All compounds were characterized by IR and NMR spectroscopy. Studies of their thermal stability in air in the temperature range of 25–500°C were performed. A mechanism of thermal destruction was proposed.

В работе синтезированы ионные жидкости с катионом 2-(алкилдиметиламино)этанола и неорганическими анионами. Проведены исследования электропроводности их растворов в ацетонитриле. Методом Ли-Уитона рассчитаны константы ионной ассоциации Ka, предельная молярная электрическая проводимости (λ0) и энергия Гиббса ассоциации (ΔG) в растворах. In this work obtained ionic liquids with 2-(alkyldimethylamino)ethanol cation and inorganic anions. Studies of the electrical conductivity of their solutions in acetonitrile have been carried out. The Li-Wheaton method was used to calculate the ion association constants Ka, the limiting molar electrical conductivity (λ0), and the Gibbs association energy (ΔG) in solutions.

New ionic liquids quaternary ammonium [(CH3)2N(CH2CH2OH)R]FeCl4 and pyridinium [C5H5NR]FeCl4 [R = CH2CH=CH2, C4H9, (CH2)3CN, CH2C6H5, C10H21] tetrachloroferrates were synthesized. Their thermal stability was studied in air in the range of 25–600°C. The thermal stability of quaternary ammonium and 1-alkylpyridinium tetrachloroferrates was compared, and the mechanism of thermal destruction was proposed.

Авторами работы получены ионные жидкости с катионом тетраалкиламмония и неорганическими анионами. Проведены исследования электропроводности их растворов в ацетонитриле. The authors of the work obtained ionic liquids with tetraalkylammonium cation and inorganic anions. Studies of the electrical conductivity of their solutions in acetonitrile have been carried out.

An investigation is performed of the electrical conductivity of a number of dicationic ionic liquids based on 3‑methylpyridinium and inorganic anions in acetonitrile. The Lee–Wheaton procedure is used to calculate constants Ka of ion association, the limiting molar electrical conductivity (λ0), and the Gibbs energy of association (ΔG) in solutions. It is shown that the nature and size of the anion are a key influence on the association of the studied ionic liquids. It is established that dicationic 3-methylpyridinium salts with bromide anions are more associated in solution than corresponding hexafluorophosphates or tetrafluoroborates.