A comparative analysis of the solubility diagrams of iodine-water-alkanol ternary systems at 25°C

The solubilities of the components of the iodine-water-propanol (1-C₃H₇OH) ternary system at 25°C and atmospheric pressure were measured for the first time. The solubility diagram of this system is a ternary system diagram with salting out. Iodine stratifies water-propanol mixtures containing 16.2–73.0 wt % alcohol. The solubility of crystalline iodine increases as the content of alcohol in the mixed solvent grows and is maximum in a mixture containing 79.0 wt % alcohol. A comparative analysis of the phase diagrams of the iodine-water-alkanol (ethanol, propanol-1, and propanol-2) systems was performed. The differences between them can likely be explained by an increase in the electron donor ability of the alcohols, which is also in agreement with the enthalpies of solution of the alcohols in water.     

Photochemically induced reaction between perfluoroacetone and ethane

The gas-phase photolysis of perfluoroacetone in the presence of ethane has been shown to result in the production of significant amounts of 1, 1-bis(trifluoromethyl)propanol-1, (CF₃)₂(C₂H₅)COH, and 1, 1, 4, 4-tetrakis(trifluoromethyl)butane-1, 4-diol, (CF₃)₂C(OH)-CH₂CH₂C(OH)(CF₃)₂. A mechanism is presented which accounts for the relative rates of formation of these products at room temperature.     

The Quantum Yield of Singlet Oxygen in Thermal Degradation of Alcohol Hydrotrioxides

The yield of singlet oxygen (¹О₂) in the decomposition of a number of hydrotrioxides of alcohols (cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclooctanol, L-menthol, 1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol, 1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol, heptan-4-ol, propanol-2, and 1-cyclopropylethanol) has been determined using the IR chemiluminescence technique. It has been shown that cyclopentanol, 1,3,3-trimethylbicyclo[2.2.1]heptan-2-ol and 1-cyclopropylethanol hydrotrioxides are efficient sources of singlet oxygen; the yield of ¹О₂ reaches up to 58%.     

Catalytic conversion of aliphatic alcohols on carbon nanomaterials: The roles of structure and surface functional groups

Carbon nanomaterials with the structure of graphene and different compositions of the surface groups are used as catalysts for the conversion of С₂–С₄ aliphatic alcohols. The conversions of ethanol, propanol- 1, propanol-2, butanol-1, butanol-2, and tert-butanol on carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are investigated. Oxidized and nonoxidized multiwalled carbon nanotubes, nanoflakes, and nanoflakes doped with nitrogen are synthesized. X-ray diffraction analysis, X-ray photoelectron spectroscopy, scanning and transmission electronic microscopies, Brunauer–Emmett–Teller method, derivatographic analyses, and the pulsed microcatalytic method are used to characterize comprehensively the prepared catalysts. It was established that all of the investigated carbon nanomaterials (with the exception of nondoped carbon nanoflakes) are bifunctional catalysts for the conversion of aliphatic alcohols, and promote dehydration reactions with the formation of olefins and dehydrogenation reactions with the formation of aldehydes or ketones. Nanoflakes doped with nitrogen are inert with respect to secondary alcohols and tert-butanol. The role of oxygen-containing and nitrogen-containing surface groups, and of the geometrical structure of the carbon matrix of graphene nanocarbon materials in the catalytic conversion of aliphatic alcohols, is revealed. Characteristics of the conversion of aliphatic alcohols that are associated with their structure are identified.     

Effect of Substituents on Nitrobenzene Reduction in the Presence of a Platinum Catalyst

The effect of substituted nitrobenzene structure on the kinetics of their catalytic reduction in propanol-2 in the presence of a platinum catalyst is studied. The reaction order with respect to a nitro compound changes in the series of the studied substrates. A satisfactory correlation between the apparent rate constants for the reaction and the E _LUMO values of the substrates is observed for several nitro compounds.     

Phase equilibria in the iodine-potassium iodide-water-propanol-2 four-component system

Isothermal-isobaric sections of the phase diagram of the iodine-potassium iodide-water-propanol-2 (2-C₃H₇OH) four-component system were studied at 25°C and atmospheric pressure. In all sections, threephase eutonic equilibria were observed with potassium iodide and crystalline iodine as solid phases. Potassium iodide was a iodine salting in agent in sections containing 15 and 25 wt % propanol-2 and a salting out agent in the section with 50 wt % alcohol. H₂O-2-C₃H₇OH (85: 15 and 75: 25 wt %) mixed solvent compositions showed a higher ability to dissolve iodine than mixture components.     

Continuous wine making by γ-alumina-supported biocatalyst

The main objective of the present work was the removal of aluminum from wines produced by γ-alumina-supported yeast cells. Reagents such as Na₂CO₃, NH₄OH, albumin, and Ca(OH)₂ were used. Calcium in the presence of albumin was effective, whereas other reagents were not so effective. Because of the improved aroma and taste of distillates produced by γ-alumina-supported biocatalyst, volatile byproducts of distillates were analyzed. They were also assessed by sensory tests. Methanol, acetaldehyde, ethyl acetate, propanol-1, isobutyl alcohol, and amyl alcohols were determined in distillates. It was noted that the amounts of higher alcohols and amyl alcohols decreased as the temperature of fermentation dropped, leading to a product of improved quality and reduced toxicity.     

Thermodynamic properties of aqueous-alcoholic solutions of sodium chloride. H<Subscript>2</Subscript>O-2-C<Subscript>3</Subscript>H<Subscript>7</Subscript>OH-NaCl

The temperature-concentration dependences of the NaCl activity coefficient in aqueous solutions of isopropanol (propanol-2) at temperatures of 298.15 and 323.15 K (solution ionic force, 0.01 to 3m; alcohol content, 10–60 wt %) were determined through the electromotive force method with an ion-selective electrode. A Pitzer model was used to mathematically describe the thermodynamic properties. The integral Gibbs energy of the solution formation of the H₂O-2-C₃H₇OH-NaCl ternary system was performed according to Darken’s method. The dissociation degree of salt in the investigated solutions was estimated using the literature data on the association constant of NaCl in aqueous-isopropanol solution.     

Carbazole derivatives as photosensitizers in cationic photopolymerization of clear and pigmented coatings

The synthesis of some carbazole compounds containing vinyl ether, epoxy or hydroxy groups is reported. They are used as photosensitizers in cationic photopolymerization of vinyl ether and epoxy systems. In clear coatings an increase of the rate of photopolymerization was observed, the most active compound being 1,3-di(carbazol-9-yl)propanol-2. The same behaviour was observed in photosensitized pigmented coatings containing TiO₂. An increase of T_g of cured films was observed in the presence of the photosensitizer; also an increase of hardness and solvent resistance was evidenced.     

Direct determination of enthalpies of vaporization of liquid compounds by a miniaturized effusion cell adapted to a commercial microcalorimeter

A miniaturized effusion cell adapted to a Sorption LKB microcalorimeter has been designed, built and tested. Vaporization is performed isothermally into a vacuum through a small orifice permitting a vapour pressure very close to the equilibrium values. The cell has been tested by measuring the enthalpies of vaporization at 298.15 K of reference liquid compounds (water, benzene, propanol-1, propanol-2) with a reproducibility better than 1%. Enthalpies of vaporization of butanol-1 and deuterated water have also been determined.     

Catalytic dehydrogenation of propanol-2 on Na-Zr phosphates containing Cu,Co, and Ni

The dehydrogenation of propanol-2 on sodium-zirconium phosphates (NZP) with the composition Na_{1 − 2x} M _x Zr₂(PO₄)₃ (x = 0.125 and 0.25) in which Na⁺ ions were replaced by M²⁺ = Co²⁺, Ni²⁺, and Cu²⁺ ions was studied. The experimental reaction activation energy E _a decreased while transition through the T* = 310−340°C temperature; above this temperature, the electrophysical and crystallographic properties of the material changed. These changes were explained by the reversible transfer of Me²⁺ ions from position M1 to M2 in the NZP lattice. Me²⁺ centers with different alcohol adsorption forms at T < T* (one-point) and T > T* (two-point) participated in the dehydrogenation reaction. For the first form, E _a and the logarithm of the preexponential factor linearly correlated with the ionic radius of M²⁺. The activity of M-NZP catalysts altered in repeated experiments and in cases when the direction of temperature variations changed.     

Structure and catalytic activity of metal complexes fixed on carriers. Hydrodehalogenation of p-bromotoluene with chemically bonded hydrogen,catalyzed by immobilized rhodium(II) complexes

The structure of Rh(II) complexes with vigorous ligands immobilized on -aminopropyl-containing silicagel (-AMPS) and polymers containing 3(5)-methyl-pyrazole and imidazole groups, was investigated. It was shown by IR spectroscopy that the ligand surroundings are maintained after application only for the Rh(II) acetate complex. For the acetonitrile and hexafluoroacetylacetonate complexes there is a replacement of the ligands by amino groups of the carrier. [Rh₂(O₂CCH₃)₄] is significantly more active than other metal complexes immobilized on -AMPS in the hydrodehalogenation of p-bromotoluene by transfer of hydrogen from NaBH₄ and propanol-2.N. D. Zelinskii Institute of Organic Chemistry, Russian Academy of Sciences, 117913 Moscow. Translated from Izvestiya Akademii Nauk, Seriya Khimicheskaya, No. 1, pp. 65–70, January, 1992.     

Planar ZrO2 Waveguides Prepared by the Sol-Gel Process: Structural and Optical Properties

ZrO₂ waveguides are prepared by the sol-gel process from a solution containing zirconiumn-propoxide and acetylacetone in propanol-2. Structural characterizations are investigated for different annealing temperatures using suitable techniques including Waveguide Raman Spectroscopy, Electron Microscopy and Atomic Force Microscopy. Films are amorphous at 300°C and the pure ZrO₂ tetragonal crystalline phase appears beyond 400°C. Crystallized films present a dense, uniform and polycrystalline structure made up by randomly oriented nanocrystallites, the diameter of which increases from 38 Å at 400°C to 53 Å at 600°C. Waveguides are at least monomode TE₀ at 632.8 nm. At this wavelength, optical losses are about, 0.8±0.2dB/cm for amorphous layers and increase up to 2.5±0.4 dB/cm for 600°C heat-treated waveguides.     

Mechanism of olefin epoxidation in the presence of a titanium-containing zeolite

The effect of the nature of a solvent on the liquid-phase epoxidation of olefins with an aqueous solution of hydrogen peroxide over a titanium-containing zeolite is studied. Butanol-1, butanol-2, propanol-1, isopropanol, methanol, ethanol, water, acetone, methyl ethyl ketone, isobutanol, and tert-butanol are examined as solvents. A mechanism of olefin epoxidation with hydrogen peroxide in an alcohol medium over a titanium-containing zeolite is proposed. Epoxidation reactions involving hydrogen peroxide and different olefins are studied experimentally.     

Dünnschichtchromatographie von Platinmetallen auf Zellulose

Zusammenfassung Die Dünnschichtchromatographie der Platinmetalle auf Zellulose in Mischungen von Salzsäure oder Bromwasserstoffsäure mit Alkoholen bzw. Ketonen wurde untersucht. Als Alkohole wurden Methanol, Äthanol, Propanol-(1), Butanol-(1) und Pentanol-(1), als Ketone Aceton, Dioxan, Äthylmethylketon und Isobutylmethylketon verwendet. Zum Teil ergaben sich beträchtliche Unterschiede zwischen denR _f-Werten der Chloro- und der Bromokomplexe dieser Metalle. Osmium wird mittels zweidimensionaler Chromatographie von den übrigen Platinmetallen getrennt. Durch Laufmittelwechsel können Pt, Pd, Ru und Rh voneinander getrennt werden.

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Thin layer chromatography of platinum metals on cellulose

Summary A study was made of the thin layer chromatography of the platinum metals on cellulose in mixtures of hydrochloric or hydrobromic acids with alcohols or ketones. The alcohols included methanol, ethanol, propanol-(1), butanol-(1) and pentanol-(1); the ketones used were acetone, dioxane, ethylmethylketone and isobutylmethylketone. In part considerable differences were observed between theR _f-values of the chloro- and the bromocomplexes of these metals. Osmium was separated from the other platinum metals by means of twodimensional chromatography. Platinum, ruthenium, palladium and rhodium can be separated from each other by change of the mobile phases.

     

The Photochemistry of Diazomethane the Reactions of Methylene with Methanol and Ethanol

In the photolysis of diazomethane-methanol. mixture, the reaction of methylene with methanol gives dimethyl ether and ethanol as products. The ratio of dimethyl ether to ethanol is found to be independent to pressure and to. the composition of diazomethane-methanol mixture. Methylene insertion into O—H bond is about 11 times faster than that into C—H bonds of methanol. The ratio decreases with increase of temperature. In the diazomethane-ethanol system, ethylmethyl ether, propanol-1 and propanol-2 are found as the products of insertion reaction of methylene into ethanol. The ratios of ethylmethyl ether to propanol-1 and to propanol-2 are both found to be almost constant and independent to pressure and to the composition of diazomethane-ethanol mixture. A small temperature effect on the ratios are observed. The rate of insertion of methylene into O—H bond is about 7.3 and 14.2 times faster than those into primary and secondary C—H bonds of ethanol, respectively.     

Solid-state 13C NMR spectroscopic examination of lower alcohol vapor sorption by cross-linked poly(methyl methacrylate) particles

The sensitivity and selectivity of methyl methacrylate-ethylene glycol dimethacrylate copolymers with respect to lower alcohol (methanol, ethanol, and propanol-2) vapors were examined by solid-state ¹³C NMR spectroscopy. A comparative analysis was carried out for the capabilities of various spectral techniques for studying sorption processes in cross-linked polymer particles.     

Fehlerm?glichkeiten bei der quantitativen Analyse polycyclischer aromatischer Kohlenwasserstoffe aus Luftstaubextrakten mit der Capillar-Gas-Chromatographie

Zusammenfassung Ein vielfach angewandtes capillargas-chromatographisches Verfahren zur Bestimmung von polycyclischen aromatischen Kohlenwasserstoffen (PAH) in der Atmosphäre wurde auf seine Zuverlässigkeit bei der Gewinnung von quantitativen Analysendaten hin geprüft. Eine PAH-Fraktion, die in unserem Labor routinemäßig durch Extraktion von atmosphärischem Schwebstaub mit Methanol, Flüssig-Flüssig-Verteilung (Cyclohexan/Methanol-Wasser) und zwei säulenchromatographischen Trennungen (SiO₂/Cyclohexan und Sephadex LH-20/Propanol-2) gewonnen wird, wurde bei dem letzten chromatographischen Schritt (Sephadex LH-20/Propanol-2) weiter fraktioniert. Durch Untersuchung der so erhaltenen Fraktionen mit Hilfe der Capillar-Gas-Chromatographie und der GC-MS-Kopplung wurden für 14 ausgewählte PAH Überlagerungen durch Störsubstanzen qualitativ und quantitativ ermittelt. Dabei zeigte sich, daß ein Teil der Fehler vermieden werden kann, wenn die PAH mit zwei und drei Ringen exakt von den interessierenden PAH mit vier und mehr Ringen abgetrennt werden. Für einige PAH sind die quantitativen Ergebnisse jedoch auch bei richtiger Schnittpunktwahl mit Vorsicht zu bewerten; zu diesen Verbindungen gehört auch das oftmals als Maß für die cancerogene Potenz einer PAH-Fraktion angesehene Benzo(a)pyren.

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Pitfalls of quantitative analysis of polycyclic aromatic hydrocarbons in airborne particulate matter by capillary gas chromatography

Summary Glass capillary gas chromatography was checked with regard to the authenticity of quantitative results for the analysis of polycyclic aromatic hydrocarbons (PAHs) in airborne particulate matter. A PAH fraction, which was routinely separated from particulate matter by solvent extraction (methanol), liquid-liquid partition (cyclohexane/methanol-water) and two steps of column chromatography (SiO₂/cyclohexane and Sephadex LH-20/propanol-2), was further fractionated with the above mentioned Chromatographic system Sephadex LH-20/propanol-2. By analyzing the fractions obtained so far with glass capillary chromatography and g.c.-m.s. coupling, the interfering substances were determined qualitatively and quantitatively concerning 14 selected PAHs. It was shown that some errors in determining PAH values may be avoided, if PAHs with less than four rings are exactly separated from those with four and more rings in the last Chromatographic step; but quantitative data for some PAHs may be biased even in case of a well separated PAH fraction. One of these PAHs is the well known benzo(a)pyrene, which has often been considered as an indicator for the carcinogenic potency of the PAHs in general.

     

Liquid–vapor phase equilibria of three-component systems of propanol-2–propanoic acid esters

The boiling points of solutions of three-component systems formed by propanol-2 and propanoic acid esters are measured at different pressures by means of ebulliometry. The coefficients of the activity of the solutions’ components are measured using Wilson and nonrandom two-liquid (NRTL) equations. The results from calculations are in line with the experimental data.

     

Catalytic properties of a copper-carbon system formed by explosive decomposition of copper acetylide

The catalytic properties of a copper-carbon system formed by the explosive decomposition of copper acetylide in the propanol-2 dehydrogenation and dehydration reaction were studied by the pulse microcatalytic method over the temperature range 60–350°C. The extent of conversion was as high as 85%. It was established that the ratio between the catalytic conversion channels of propanol-2 depended on the method of acetylide decomposition (explosion in air or in vacuum).