Researches on 2, 1, 3-thia- and selenadiazole

4-Hydroxy-, 4-hydroxy-5-methyl-, 4-hydroxy-7-methylbenzo-2,1,3-thiadiazoles are polymorphous.4-Hydroxybenzo-2,1,3-thiadiazole (I), 4-hydroxy-5-methyl- and 4-hydroxy-7-methylbenzo-2, 1, 3-thiadiazoles (II and III) melt at 114–115°, 110–112°, 100–102° C, respectively, after recrystallization from water [2–4], but after recrystallization from petrol ether [5] they melt at 128–129°, 124–125°, and 119–120° C [5]. In this connection we recrystallized these phenols repeatedly from petrol ether after recrystallizing them from water, and their melting points rose as expected [5]. On the other hand, the compounds with melting points 128–129°, 124–125°, 119–120° C (ex petrol ether), after repeated crystallization from water melted at 114–115°, 110–112°, 100–102° C, respectively.For Part XXXVIII see [1].     

Surface redox polymerized SPEEK–MO2–PANI (M = Si, Zr and Ti) composite polyelectrolyte membranes impervious to methanol

We reported sulfonated poly(ether ether ketone) (SPEEK, 61% degree of sulfonation)–metal oxides (MO₂:SiO₂, TiO₂ and ZrO₂)–polyaniline composite membranes. Metal oxides were incorporated into the swelled SPEEK membrane by sol–gel method and cured by thermal treatment. SPEEK–metal oxide membranes surfaces were modified with polyaniline (PANI) by a redox polymerization process. It was observed that water retention capacity of membrane was increased and methanol permeability was reduced due to synergetic effect of metal oxides and surface modification with polyaniline. These composite membranes showed extremely low methanol permeability (1.9–1.3 × 10⁻⁷ cm² s⁻¹), which was lower than till reported values either for SPEEK–metal oxide or SPEEK/PANI membranes. Relatively high selectivity parameter (SP) values at 343 K of these membranes, especially S–SiO₂–PANI and S–TiO₂–PANI, indicated their great advantages over Nafion117 (N117) membrane for targeting on moderate temperature applications due to the synergetic effect of MO₂ and PANI in SPEEK matrix. S–TiO₂–PANI and N117 showed comparable cell performance in direct methanol fuel cell (DMFC).     

Sulfonated poly(ether ether ketone)-based silica nanocomposite membranes for direct ethanol fuel cells

This paper reports on the preparation and characterization of sulfonated poly(ether ether ketone) (sPEEK)-based mixed matrix membranes. The inorganic matrix consisted of silica: Aerosil^®380, tetraethoxysilane (TEOS) or a combination of both to obtain an interconnected silica network. The behavior of these membranes in ethanol–water systems was studied for application in a direct ethanol fuel cell (DEFC). Uptake measurements showed that the converted TEOS content had a strong influence on the hydrophilicity of the membranes. Proton conductivity was strongly related to the water content in the membrane, but the proton diffusion coefficients of membranes with various Aerosil^®380–TEOS combinations were similar. Dynamic measurements in liquid–liquid (L–L) and liquid–gas (L–G) systems were performed to study the ethanol transport through the membrane. No reduction in ethanol permeability was obtained in the L–L system, but a remarkable reduction was obtained in the L–G system when 2 M ethanol was applied. The reinforcing characteristic of the combined Aerosil^®380–TEOS-system were best observed at 40 °C with 4 M ethanol. The fuel cell performance prediction based on the selectivity of proton diffusion coefficient to ethanol permeability coefficient showed for nearly all composite membranes an improvement with respect to the polymeric reference. The presence of an inorganic phase led to relatively constant proton diffusion coefficients and lower ethanol permeability coefficients in comparison with the polymeric reference.     

Determination of decabromodiphenyl ether in sediments using selective pressurized liquid extraction followed by GC–NCI-MS

A method based on selective pressurized liquid extraction (SPLE) followed by gas chromatography–negative ion chemical ionization-mass spectrometry (GC–NCI-MS) has been evaluated for analysis of decabromodiphenyl ether (PBDE-209) in sediment samples. Instrumental operating conditions such as source temperature and system pressure were optimized in the NCI-MS system, giving an instrumental detection limit of 2 pg. The limit of determination of the entire SPLE–GC–NCI-MS procedure was around 50 pg g^–1 dry weight (dw), with repeatability of replicates between 4 and 21% relative standard deviation. Application of the method to 13 different river and marine sediment samples collected in Spain revealed that levels of decabromodiphenyl ether ranged between 2 and 132 ng g^–1 dry weight.     

Electroanalytical study of diethyl and dibutyl phthalate in micellar and oil-in-water emulsified media

A polarographic study was carried out of the reduction processes of diethyl and dibutyl phthalate in micellar solutions with the cationic surfactant Hyamine 1622, and in an emulsified medium from aliquots of the phthalates dissolved in a diethyl ether: ethyl acetate (1:9) mixture and Hyamine 1622 as emulsifying agent. The characteristics of the reduction processes in both media were established. The number of electrons involved was higher for the base form of the electroactive species. Using dpp at E=–50 mV, the detection limits obtained in the emulsified medium were 6.7×10^–8 and 7.4×10^–7 moll^–1 for diethyl phthalate and dibutyl phthalate, respectively. Interferences between the two phthalates were studied, and the possibility of carrying out the overall determination of both phthalates was demonstrated. Good results were obtained when applying the polarographic method developed in the emulsified medium to determine diethyl phthalate by dpp in spiked milk after extraction of the analyte with diethyl ether: ethyl acetate (1:9).     

Solvent extraction of amino acids into a room temperature ionic liquid with dicyclohexano-18-crown-6

Amino acids Trp, Gly, Ala, Leu are extracted efficiently from aqueous solution at pH 1.5–4.0 (Lys and Arg at pH 1.5–5.5) into the room temperature ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF₆) with dicyclohexano-18-crown-6 (CE). The most hydrophilic amino acids such as Gly are extracted as efficiently as the less hydrophilic (92–96%). The influence of pH, amino acid and crown ether concentration, volume ratio of aqueous and organic phases, and presence of some cations on amino acid recovery were studied. The ratio of amino acid to crown ether in the extracted species is 1:1 for cationic Trp, Leu, Ala, and Gly and to 1:2 for dicationic Arg and Lys. This ionic liquid extraction system was used successfully for the recovery of amino acids from pharmaceutical samples and fermentation broth, and was followed by fluorimetric determination.These results were published in part in Smirnova SV (2002) Ph.D. Thesis, Moscow State University.     

Formation of Ethers from Alcohols with Chloride Complexes of Platinum(II) as Catalysts

A new catalytic reaction of the etherification of alcohols in the system ROH-PtCl ₄ ²⁻ has been observed. At 70 °C in the presence of catalytic amounts of chloride complexes of platinum(II) methanol gave dimethyl ether. Methyl tert-butyl ether and di-tert-butyl ether were formed analogously from a mixture of methanol and tert-butanol. In the reaction with ethanol the products were diethyl ether and a π-ethylene complex of platinum(II). It is suggested that the step-wise mechanism includes the oxidative addition of the alcohol with the intermediate formation of an alkyl complex of platinum(IV), the decomposition of which by reductive elimination under the influence of a second molecule of alcohol or an alkoxide anion gives an ether and regenerates the catalyst, a chloride complex of platinum(II).__________Translated from Teoreticheskaya i Eksperimental’naya Khimiya, Vol. 41, No. 3, pp. 190–193, May–June, 2005.     

Triphenylbismuth Bis(2,4,6-Tribromophenoxide): Synthesis and Structure

A reaction of triphenylbismuth with 2,4,6-tribromophenol and hydrogen peroxide (molar ratio 1 : 2 : 1) in ether affords triphenylbismuth bis(2,4,6-tribromophenoxide). The complex obtained was structurally characterized by X-ray diffraction analysis. The coordination polyhedron of the Bi atom is a trigonal bipyramid with axial aroxy groups. The Bi–C and Bi–O bond lengths are 2.202(4), 2.203(4), 2.212(4) and 2.241(3), 2.245(3) Å, respectively. The intramolecular Bi···Br(1,4) contacts are 3.629(1) and 4.077(1) Å, respectively.     

Synthesis and Structure of Triphenylantimony Bis(Acetophenoneoximate)

Triphenylantimony bis(acetophenoneoximate) was synthesized by the reaction of triphenylantimony with hydrogen peroxide in the presence of acetophenone oxime (taken in the molar ratio of 1 : 1 : 2) in ether. The structure of the obtained compound was determined by X-ray diffraction. The Sb atom has a distorted trigonal-bipyramidal coordination with the oxime groups in the axial positions. The Sb–C(Ph)_eq bond lengths are 2.110(1)–2.113(1) Å, and the Sb–O distances are 2.058(1) and 2.067(1) Å. The intramolecular Sb(1)···N(1, 2) contacts and O(1)SbO(2) axial angle are 2.990(1), 2.916(1) Å and 172.49(4)°, respectively.     

Hydrogen bond formation to cyclic and acyclic polyethers

Equilibrium constants and enthalpies of hydrogen-bond formation of mcresol to various cyclic (crown) and acyclic polyethers have been determined in benzene solvent. Equilibrium constants indicated no evidence for an operative macrocyclic effect; the relationship between the increasing size of the equilibrium constant and the number of ether oxygens was rationalized with a simple statistical thermodynamic model. Enthalpies of interactions ranged between –19 and –23 kJ-mol^–1. In agreement with PCILO calculations, enthalpies of interaction were essentially independent of the number of oxygen atoms in the ether; no significant difference in enthalpies of interaction between cyclic and acyclic ethers was found.     

Thermodynamic study of perfluorohexane + ether mixtures: VLE, LLE, and H

Vapour–liquid equilibria (VLE), liquid–liquid equilibria (LLE), and excess enthalpies (H^E) of binary mixtures of perfluoro-n-hexane plus an ether (diethyl, dipropyl, dibutyl, butyl methyl, and butyl ethyl ether), have been determined using a head-space gas-chromatographic technique, a turbidimetric apparatus, and a heat-flow calorimeter, respectively. A recently designed titration technique and calculation procedure have been used to obtain H^E from heats of solution. The observed liquid–liquid coexistence curves have been compared with those predicted by the activity coefficients γ_i and their temperature dependence. All mixtures are strongly endothermic (H^E > 0) and show large positive deviations from ideality (G^E > 0), which increase with the size of the ether. Molecular interactions have been examined by calculating and discussing solvation functions and Kirkwood–Buff (KB) integrals. Perfluorohexane proved to be an inert molecule that interacts with ethers more weakly than hexane.     

Gas Chromatography–Mass Spectrometric Determination of Traces of Ether-Type Icing Inhibitors in Free-Floating Fuels

A gas chromatographic–mass spectrometric (GC–MS) assay method has been developed for simultaneous determination of ethylene glycol monomethyl ether (EGME) and diethylene glycol monomethyl ether (DEGME) in spilled aviation fuels. Ethylene glycol monobutyl ether (EGBE) and ethylene glycol monoethyl ether (EGEE) were used as internal standard and surrogate, respectively. Sample preparation consisted of back-extraction with 7 mL dichloromethane after extraction of 50 mL of fuel with 2 mL of water. The extract was concentrated to dryness, dissolved in 100 L methanol, and analyzed by GC–MS with selected-ion monitoring (SIM). The peaks had good chromatographic properties on a semi-polar column. EGME and DEGME were extracted from fuel with high recovery of 75 and 85%, with small variations, respectively. Method detection limits were 1.3 and 1.0 ng mL^–1 for EGME and DEGME, respectively, in spilled fuel. DEGME was detected at concentrations of 22.6 and 19.7 ng mL^–1 in two samples from among five free-floating samples collected in a tunnel of a subway station located in the vicinity of an army base in Korea. The method might be useful for differentiation between the fuel-types kerosene and JP-8, which might originate from a storage tank.     

Synthesis and Structure of Organoantimony Peroxides

Organoantimony peroxides (Ar₂SbO)₄(O₂)₂ (Ar = Ph, p-Tol) were synthesized by oxidation of triarylantimony with hydrogen peroxide in the presence of nitrosophenol or 4-chlorophenol in an ether solution. X-ray diffraction analysis of peroxides obtained revealed that four antimony atoms have octahedral coordination and are connected via bridging oxygen atoms and two peroxide groups. The C–Sb, Sb–O_br, Sb–OO, and O–O distances are equal to 2.106–2.127, 1.958–1.974, 2.202–2.246, 1.471, 1.470 Å (Ar = Ph) and 2.086–2.139, 1.932–1.983, 2.215–2.289, 1.445–1.466 Å (Ar = p-Tol).     

Products of the ozonolysis of epitorulosol

The structure of the products of the ozonization of epitorulosol [13S-labda-8(20),14-diene-13,19-diol] (I) has been established. Compound (I) (1 g) was ozonized at –30°C in 100 ml of absolute CH₃OH until saturation. The O₃ was driven off by nitrogen, 1 ml of (CH₃)₂S was added at –10°C, and the mixture was stirred for 1 h each at –10, 0, and 20°C and was worked up, and the product (1.13 g) was chromatographed on a column containing 45 g of silica gel. The following were eluted in the order of increasing polarity: 420 mg of 19-hydroxy-8,13;8,14-diepoxy-13S-15,20-bisnorlabdan-14-one (II), mp 141.5–142.5°C (from petroleum ether), [] _D ²³ –63° (c 3.1); 255 mg of 8,13;8,14-diepoxy-13S-15,20-bisnorlabdane-14,19-diol (III), characterized in the form of the diacetate (IV) with mp 100–107°C (from petroleum ether); and 117 mg of 19-hydroxy-14,15,20-trisnorlabdane-8,13-dione (V), mp 82–83°C [from petroleum ether-diethyl ether (1:1)], [] _D ²⁶ –40° (c 1.7). The same products but in different ratios were formed on the ozonization of (I) in CH₂Cl₂-Py or in hexane followed by decomposition of the ozonide by heating with H₂O. The []_D values were measured in CHCl₃. Details of the IR and PMR spectra are given.Institute of Chemistry, Academy of Sciences of the Moldavian SSR, Kishinev. Institute of Organic Chemistry, Siberian Branch of the USSR Academy of Sciences, Novosibirsk. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 524–527, July–August, 1987.     

Äther als Katalysatoren für die Reaktion von Diboran mitLewis-Basen; vereinfachte Darstellung von Carbonylboran und Phosphinboran

Zusammenfassung Die Reaktionen von B₂H₆ mit CO zu H₃BCO und mit PH₃ zu H₃BPH₃ werden in Lösung durch Äther katalytisch beschleunigt. Die Bildungsgeschwindigkeit von H₃BCO nimmt in der Reihenfolge Diäthyläther < Diglyme < Monoglyme < < Dimethyläther (mit der Basenstärke der Äther) zu. Unter optimalen Bedingungen werden die beiden Addukte mit fast quantitat. Ausb. gebildet (für H₃BCO: – 45° in Monoglyme, 1 Atm. CO; für H₃BPH₃: – 60° in Diäthyläther). In Dimethyläther und Tetrahydrofuran werden durch eine Konkurrenzreaktion zunehmend Äther—Boran-Komplexe gebildet.

---

Ether catalyzed reaction of diborane with lewis bases; simplified preparation of carbonyl borane and phosphine borane

The reactions of B₂H₆ with CO to H₃BCO and with PH₃ to H₃BPH₃ in solution are accelerated catalytically by ethers. In the series diethyl ether < diglyme < monoglyme < dimethyl ether the rate of formation of H₃BCO increases with the base strength of the ethers. Using optimized conditions both adducts are obtained with nearly quantitative yields (for H₃BCO: – 45° in monoglyme, 1 atm. CO; for H₃BPH₃: – 60° in diethyl ether). In dimethyl ether and tetrahydrofurane ether—borane complexes are formed increasingly via a competitive reaction.

     

The Solvent Effect on the Rate of Reaction between Propanethiol and Chlorine Dioxide

The products and kinetics of the liquid-phase oxidation of propanethiol by chlorine dioxide in organic media (n-heptane, 1,4-dioxane, carbon tetrachloride, benzene, diethyl ether, ethyl acetate, acetone, and acetonitrile) at temperatures from –10 to 70°C were examined. The reaction rate constants and activation parameters were measured in the above solvents. A strong solvent effect on the reaction kinetics was found (k= 1.67 × 10^–3or 52.7 l mol^–1s^–1(25°C) in heptane or acetonitrile, respectively). The data were analyzed in terms of the Leydler–Eyring and Koppel–Palm equations. The formation of high-polarity intermediates in the test reaction was suggested.     

Acyl Iodides in Organic Synthesis: VI. Reactions with Vinyl Ethers

Reactions of acetyl iodide with butyl vinyl ether, 1,2-divinyloxyethane, phenyl vinyl ether, 1,4-di-vinyloxybenzene, and divinyl ether were studied. Vinyl ethers derived from aliphatic alcohols (butyl vinyl ether and 1,2-divinyloxyethane) react with acetyl iodide in a way similar to ethyl vinyl ether, i.e., with cleavage of both O–Csp2 and Alk–O ether bonds. From butyl vinyl ether, a mixture of vinyl iodide, butyl acetate, vinyl acetate, and butyl iodide is formed, while 1,2-divinyloxyethane gives rise to vinyl iodide, vinyl acetate, and 2-iodoethyl acetate. The reaction of acetyl iodide with divinyl ether involves cleavage of only one O–Csp2 bond, yielding vinyl acetate and vinyl iodide. In the reactions of acetyl iodide with phenyl vinyl ether and 1,4-divinyloxybenzene, only the O–CVin bond is cleaved, whereas the O–CAr bond remains intact.     

Synthesis and Structure of Bis(2,4,6-Tribromophenoxy)triphenylantimony

Bis(2,4,6-tribromophenoxy)triphenylantimony was synthesized by reacting triphenylstibine with 2,4,6-tribromophenol in ether in the presence of hydrogen peroxide. Its structure was determined by X-ray diffraction analysis. The coordination polyhedron of the Sb atom is a distorted trigonal bipyramid with the aroxy groups in the axial positions. The bond lengths are Sb(1)–C(Ph) 2.095(4)–2.106(4) Å and Sb(1)–O(1,2) 2.099(3) and 2.092(3) Å. The value of the O(1)SbO(2) axial angle is 177.3(1)°.     

Potassium and cesium thiocyanate complexes with diphenyloxa-21-crown-7: Synthesis and vibration spectra. Selective properties of dipnehyloxa-21-crown-7

Novel K and Cs complexes with diphenyloxa-21-crown-7 (2,3,5,6-dibenzo-1,4,7,10,13,16,19-heptaoxacyclo-heneicosadiene-2,5; DPO21C7) are synthesized and isolated in a solid state, and their IR spectra (4000–400 cm^–1) are studied. Only four ether O atoms of crown ether are involved in coordination. Conformation of a macrocycle in the complexes depends on the cation size. The potentiometric selectivity of diphenyloxa-21-crown-7 toward Cs⁺ ions was found to be the greatest.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 163–167.Original Russian Text Copyright © 2005 by Ivanova, Dorokhov, Pyatova, Galkina, Yakshin, Tsivadze.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date.