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].     

Dielectric investigation of the glass relaxation in poly(vinyl acetate) and poly(vinyl chloride) under high hydrostatic pressure

Measurements of the complex relative permittivity of poly(vinyl acetate) from 35 °C to 190 °C and poly(vinyl chloride) from 90 °C to 150 °C in the frequency range 10^–2 –10⁷ Hz and the pressure range 1–5000 bar are reported. Details of the pressure generating system and of the dielectric equipment are described.     

Critical micelle concentrations for alkyltrimethylammonium bromides in water from 25 to 160°C

Critical micelle concentrations were determined by conductance measurements for decyl-, dodecyl-, tetradecyl- and hexadecyltrimethylammonium bromide in water at 25, 60, 95, 130, and 160°C. The results are discussed in terms of the equilibrium model and the nonlinear Poisson-Boltzmann model for micelle formation. The free energies of transferring a methylene group from water to the oil-like interior of the micelle are found to be –781 at 25°C, –796 at 60°C, –819 at 95°C, –815 at 130°C, and –787 at 160°C cal-mol^–1.     

The first ionization constant from 25 to 200°C and 2000 bar for orthophosphoric acid

The ionization constant of orthophosphoric acid, determined by conductivity measurements, decreased from 7.11×10^–3 at 25°C to 6.2×10^–4 mol-kg^–1 at 200°C. The pressure effect to 2000 bar was also measured and the ratio K₂₀₀₀/K₁ is 2.7 at 25°C and 3.7 at 200°C. The standard partial molar volume change for the ionization at 1 bar, , changes from –16.1 at 25°C to –33.3 cm³-mol^–1 at 200°C. The partial molar compressibility change for the ionization, , varies from –3.8×10^–3 to –8.3×10^–3 cm³-mol^–1 bar^–1 over the same temperature range.     

Potentiometric Determination of the First Hydrolysis Constant of Gallium(III) in NaCl Solution to 100°C

The hydrolysis equilibrum of gallium (III) solutions in aqueous 1 mol-kg^–1 NaCl over a range of low pH was measured potentiometrically with a hydrogen ion concentration cell at temperatures from 25 to 100°C at 25°C intervals. Potentials at temperatures above 100°C increased gradually because of further hydrolysis of the gallium(III) ion, followed by precipitation. The results were treated with a nonlinear least-squares computer program to determine the equilibrium constants for gallium(III)–hydroxo complexes using the Debye–Hückel equation. The log K (mol-kg^–1) values of the first hydrolysis constant for the reaction, Ga³⁺ + H₂O GaOH²⁺ + H⁺ were –2.85 ± 0.03 at 25°C, –2.36 ± 0.03 at 50°C, –1.98 ± 0.01 at 75°C, and –1.45 ± 0.02 at 100°C. The computed standard enthalpy and entropy changes for the hydrolysis reaction are presented over the range of experimental temperatures.     

The Effect of Preliminary Treatment on the Catalytic Activity of Cobalt–Silica Gel Catalysts in the Complete Oxidation of Methane

The effect of temperature in multiple oxidative–reductive treatments on the activity of cobalt–silica gel catalysts in the complete oxidation of methane is studied. A decrease in the temperature of oxidative–reductive treatments from 500°C to 300°C results in an irreversible decrease in the activity of samples prepared by the impregnation of SiO₂with cobalt nitrate. A sample prepared from cobalt acetate and calcined at 500°C shows a lower activity, which was close to the activity of samples prepared from nitrates and calcined at 300°C.     

Insect pheromones and their analogues. XVI. Practical synthesis of hexadec-9Z-enal — A component of the sex pheromone of the cotton bollwormHeliothis armigera

A synthesis of hexadec-9Z-enal — a component of the sex pheromone of the cotton boll-wormHeliothis armigera (Hübner) — based on cyclooctene (I) is proposed. Through a solution of 22 g of (I), 250 ml of cyclohexane, and 40 ml of MeOH is passed (at 5°C) 0.2 M O₃/O₂, the solution is decanted off, and the precipitated ozonide is dissolved in 200 ml of MeOH and is reduced with 19 g of NaBH₄ (40°C) with the isolation, after the usual working up, of 23.4 g of octane-1,8-diol (II). From 0.5 mole of (II) and 0.6 mole of 45% HBr 8-bromooctan-1-ol (III) is obtained and this is converted into 1-(2-THPL)oxy)-8-bromooctane (IV). The condensation of (IV) with oct-1-yne (Ar, LiNH₂, HMPTA, 10°C, 1 h, and then 55°C, 10 h) leads to 1-(2-THPL-oxy)hexadec-9-yne (V) the hydrolysis of which (MeOH, H₂O, p-TsOH, 20°C for 20 h) yields hexadec-9-yn-ol (VI). The reduction of (VI) (Et₂O, iso-BuMgBr, Cp₂TiCl₂, 0°C, 15 min, then 20°C, 1 h) yieldshexadec-9Z-en-l-ol (VII). The oxidation of (VII) (PyHCrO ₃ ⁺ Cl^–, CH₂Cl₂, 20°C, 2 h) gives hexadex-9Z-enal (VIII). Characteristics of the compounds (yield (%), n _D ^{20 (25)}: (II) – 80, mp 61–62°C; (III) – 75, 1.4807; (IV) – 99, —; (V) – 52, 1,4650; (VI) – 85, 1.4657; (VII) – 99, 1.4650; (VIII) – 98, 1.4600. Characteristics of the IR and PMR spectra of compounds (V–VII) are given.Institute of Chemistry, Bashkir Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 286–289, March–April, 1987.     

Investigation of the aqueous lithium and magnesium halide systems

The solubilities of the system LiBr–MgBr₂–H₂O have been investigated at 25°C and 50°C. It is established that the system is of a simple eutonic type. Pitzer's model is used for calculating the thermodynamic functions needed for plotting the solubility isotherms of the systems LiX–MgX₂–H₂O (X=Cl, Br) at 25°C. According to calculations made, the Gibbs energy of formation of LiCl·MgCl₂·7H₂O from simple salts is _rG°_m=–2.01 kJ-mol^–1, while the value _fG°_m=–2748 kJ-mol^–1 corresponds to formation from the elements.     

Determination of differences in free and bound water contents of beef muscle by DSC under various freezing conditions

The differences in bound water content of beef semimembranous muscle samples obtained from previously chilled (24 h at +4°C) middle-aged beef carcasses were determined by the use of DSC. Initially, samples obtained from fresh, unprocessed meat were frozen at –40, –50 or –65°C to determine their melting peaks for freezable water (free water) content with the use of DSC. The samples were then subjected to an environment with an ambient temperature of –30, –35, –40 or –45°C, with no air circulation, or with an air circulation speed of 2 m s^–1, until a thermal core temperature of –18°C was attained; this was followed by thawing the samples until a thermal core temperature of 0°C was reached. This process was followed by subjecting the samples to the ambient temperatures mentioned above, to accomplish complete freezing and thawing of the samples, with DSC, and thereby determination of the freezable water contents, which were then used to determine the peaks of melting. The calculated peak areas were divided by the latent heat of melting for pure water, to determine the freezable water contents of the samples. The percentage freezable water content of each sample was determined by dividing its freezable water content by its total water content; and the bound water content of each sample was determined by subtracting the percentage free water content from the total. In view of the fact that the free water content of a sample is completely in the frozen phase at temperatures of –40°C and below, the calculations of free and bound water contents of the samples were based on the averages of values obtained at three different temperatures.     

Analogs of D(+)-pantothenic acid. V. Synthesis and investigation of the structure of N-pantoyl derivatives of proline

The synthesis of pantothenic acid analogs is described. Boiling the Na salt of L-proline (L-I) with D-(–)-pantolactone (D-II) in MeONa Yielded 53.91% of N-D-pantoyl-L-proline (III), [] _D ² ° –52° (c 2; MeOH), and 19.18% of cyclo(N-D-pantoyl-L-proline) (IV), mp 119–121°C (ethanol), [] _D ² ° –68.9° (c 2; MeOH). The following were obtained similarly: N-L-pantoyl-L-proline, cyclo(N-L-pantoyl-L-proline), N-D-pantoyl-D-proline, cyclo(N-D-pantoyl-D-proline), N-L-pantoyl-D-proline, cyclo(N-D-pantoyl-hydroxyproline), and N--hydroxybutyryl-L-proline. By fusing D-II and DL-I at 140°C cyclo(N-D-pantoyl-DL-proline) and prolylproline anhydride (V) were obtained. Compound (V) with mp 136–138°C was synthesized from DL-1 by heating at 140°C. The PMR spectra of compounds (III-V) are given. The IR spectra of compounds (III and IV) are discussed.All-Union Scientific-Research Vitamin Institute, Moscow. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 378–383, May–June, 1979.     

Pheromones of insects and their analogs

Dodec-8Z-en-1-ol (VIII) and tetradec-8Z-en-1-ol (IX) and the corresponding acetates (X and IX) — components of the sex pheromones of many species of Lepidoptera — have been synthesized from cyclooctene (I) in three stages. The ozonolysis of (I) (–70°C, CH₂Cl₂-MeOH, NaHCO₃; –20°C, Ac₂O/Et₃N) led to methyl 8-oxooctanoate (II). The DNPH of (II), (III), mp 59–61°C. The coupling of (II) with n-C₃H₁₇ CH=PPh₃ (IV) or with n-C₅H₁₁ CH=PPh₃ (V) (–70°C, 2 h; 25°C, 15 h, Ar) gave the methyl esters of dodec-8Z-enoic (VI) and tetradec-8Z-enoic (VII) acids, respectively. The reduction of (VI) and (VII) [(i-Bu)₂AlH, 0°C, 2 h; 25°C, 15 h] gave the corresponding alcohols (VIII) and (IX) by the acetylation (Ac₂O-Py, 25°C, 24 h) of which, (X) and (XI), were obtained. The yields (%): (II) 80, (VI) 45, (VII) 60, (VIII) 95, (IX) 90, (X) 75, (XI) 74. The IR and PMR spectra of compounds (II) and (VI–XI) are given.Institute of Chemistry, Bashkir Scientific Center, Urals Branch, Academy of Sciences of the USSR, Ufa. Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 276–279, March–April, 1989.     

A temperature-dependent dynamic rearrangement of cis-(R,S)-[Pd(egta)]2– (egta4–=glycine,N,N′-(1,2-ethanediylbis(oxy-2,1-ethanediyl)bis[N-carboxymethyl]) in aqueous solution

The cis-(R,S)-[Pd(egta)]2– complex, egta4–=glycine, N,N-(1,2-ethanediylbis(oxy-2,1-ethanediyl)bis[N-carboxymethyl]), has been examined by 1H- and 13C-n.m.r. methods over the 18.0 to 95.0°C range in D2O. A dynamic process occurs above 65°C which makes the protons on the NCH2 functionalities of the egta tether become 1H-n.m.r. equivalent. The two states that interconvert coalesce at 81°C. Evidence from 13C-n.m.r. spectra obtained at 81°C show that the in-plane coordinated carboxylates are not lost, but rather a pendant carboxylate becomes attached with loss of the central imino donor. The resultant palladium(II)NO3 intermediate is able to reform cis-(R,S)-[Pd(egta)]2– or, presumably, give trans-(R,R)-[Pd(egta)]2–. The rate limiting step occurs with a rate constant of 178s–1 at 81°C and an activation energy of 20.5kJ/mol. However, competitive aquation of glycinato donors above 85°C prevents isolation of a stable trans-(R,R)-[Pd(egta)]2– isomer.     

Synthesis and thermal decomposition of haloalkoxy-sym-triazines

Reaction of [2-methylthio-6-dialkylamino-sym-triazin-4-yl]trimethylammonium chlorides with ethylene chlorohydrin gave 2-methylthio-4-(2-chloroethoxy)-6-dialkylamino-sym-triazines, which are converted to 2-methylthio-3-(2-chloroethyl)-4-oxo-6-dialkylamino-3,4-dihydro-symtriazines when they are heated to 115–120°C and to the corresponding tetrahydrothiazolo-symtriazine derivatives when they are heated at 180–190°C.See [1] for communication II.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1420–1423, October, 1977.     

Measurement of mutual diffusion coefficients,densities, viscosities,and osmotic coefficients for the system KSCN-H2O at 25°C

Mutual diffusion coefficients measured on the volume-fixed frame of reference are reported for KSCN-H₂O at 25°C over the concentration range 0.0 to 10.26 mol-dm^–3. The diffusion coefficient at infinite dilution was obtained from limiting ionic equivalent conductances of K⁺ and SCN^–. Low concentration conductances of KSCN-H₂O at 25°C used to obtain the limiting ionic equivalent conductance of SCN^– are reported. Values of density and viscosity for this system are reported from 0.0 to 10.30 mol-dm^–3. Osmotic coefficienss of KSCN-H₂O at 25°C were measured by the isopiestic method. These are reported over the concentration range of 0.30 to 24.94 molal (saturation). Values of thermodynamic diffusion coefficients for the concentration range 0.0 to 10.26 mol-dm^–3 are tabulated. Results are compared to other potassium salts with monovalent anions at 25°C.     

Über die Gewinnung und Thermostabilität der Chalkogenate von Antimon und Wismut, 2. Mitt.: Gewinnung und Untersuchung der Thermostabilität von Wismuttellurit

Zusammenfassung Wismuttellurit-Trihydrat Bi₂(TeO₃)₃·3H₂O wurde hergestellt und sein Verhalten thermisch, thermogravimetrisch, chemisch sowie phasen-röntgenographisch studiert. Es wurde festgestellt, daß bei 175–192°C das Trihydrat in das Dihydrat übergeht, das bei 275–300°C eine monotrope Umwandlung erfährt. Bei weiterem Erhitzen erfolgt eine partielle Oxidation des Te(IV) zu Te(VI), begleitet von einem exothermen Effekt, der bei 348–366°C auftritt. Die vollkommene Entwässerung der Substanz tritt bei 480–500°C ein. Bei 525–600°C wird Te⁶⁺ wieder zu Te⁴⁺ reduziert und schmilzt das Wismuttellurit.

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Preparation and thermostability of the chalkogenates of antimon and bismuth, II: Preparation and thermostability of bismuth tellurite

Bismuth tellurite—the tri-hydrate—has been prepared. By thermal, thermo-gravimetric, chemical, as well as phaseroentgenographic analysis, the behaviour of Bi₂(TeO₃)₃·3H₂O upon heating has been studied. It was found that at 175–192°C the tri-hydrate passes into the di-hydrate, which at 275–300°C undergoes a monotropic transformation. On further heating, a partial oxidation of Te(IV) to Te(VI) takes place, accompanied by an exothermal effect at 348–366°C. The complete desiccation of the substance takes place presumably at 480–500°C. At 525–600°C Te⁶⁺ is again reduced to Te⁴⁺ and the bismuth tellurite melts.

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Mit 2 Abbildungen     

Beitrag zur Kenntnis der Systeme Titan—Chrom—Stickstoff,Zirkonium—Chrom—Stickstoff und Hafnium—Chrom—Stickstoff

Zusammenfassung Das ternäre System Ti–Cr–N wurde bei 1000° C und 1200° C mit Hilfe von metallographischen und röntgenographischen Methoden untersucht. Die Mononitride TiN und CrN bilden eine lückenlose Reihe von Mischkristallen; dieVegardsche Kurve weicht schwach negativ von der Geraden ab. Es konnte keine ternäre Verbindung gefunden werden. Für 1000° C wird ein Vorschlag für einen isothermen Schnitt durch das System Ti–Cr–N entworfen.Die Untersuchungen in den Systemen Zr–Cr–N und Hf–Cr–N beschränkten sich auf den Bereich der pseudobinären Schnitte ZrN/CrN und HfN/CrN. Um die Stabilität des weniger stabilen CrN sicherzustellen, wurden bei den Versuchstemperaturen folgende Stickstoffdruck-Bedingungen gewählt: 1 at N₂ bei 1000° C, 30 at N₂ bei 1200° C und 250 at N₂ bei 1400° C.Die isotypen Phasen ZrN und CrN zeigen eine Mischungslücke; aus dem Temperaturverlauf der Mischungslücke kann angenommen werden, daß sie sich bei 1440° C und 50 Mol% ZrN schließt.Im pseudobinären System HfN–CrN konnte im untersuchten Temperaturbereich lückenlose Mischbarkeit zwischen den Komponenten festgestellt werden. Eine Entmischung tritt, wenn überhaupt, nur bei Temperaturen unterhalb 1000° C auf. DieVegardkurve der Gitterparameter der Mischkristalle zeigt eine schwach positive Abweichung von der Geraden.

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About the ternary systems titanium—chromium—nitrogen, zirconium—chromium—nitrogen and hafnium—chromium—nitrogen

The ternary system Ti–Cr–N has been investigated by X-ray powder technique and by metallographic methods in two isothermic sections at 1000° C and 1200° C. The isotypic mononitrides TiN and CrN form a complete series of solid solutions, theVegard's curve shows a slight negative deviation from linearity. No ternary compound could be observed. A tentative phase diagram for an isothermic section at 1000° C is given.Investigation of the systems Zr–Cr–N and Hf–Cr–N was restricted to the pseudobinary sections ZrN–CrN and HfN–CrN. To ensure the stability of the less stable component (CrN) the following pressure conditions were chosen: 1 atm N₂ at 1000° C, 30 atm N₂ at 1200° C, 250 atm N₂ at 1400° C. The isotypic compounds ZrN and CrN exhibit a miscibility gap, which diminishes with increasing temperature. The cirtical point can be estimated to be at 1440° C and 50 mol% ZrN. In the pseudobinary system HfN–CrN a complete series of solid solutions could be observed. A miscibility gap should occur, if ever, at temperatures below 1000° C.Vegard's curve for the lattice parameters of the solid solutions (Hf, Cr)N shows a slight positive deviation from linearity.

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Herrn Prof. Dr.H. Nowotny gewidmet.

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Auszug aus der von der Fakultät für Naturwissenschaften der T. H. Wien approbierten Doktor-Dissertation des Herrn Dipl.-Ing.F. Petter.     

Kinetik der Diazotierung des Anilins in methanolischer Bromwasserstoff- und Chlorwasserstofflösung, 2. Mitt.

The kinetics of the diazotization of aniline in 0.003n to 0.4n methanolic HBr-and HCl-solution, resp., were determined (HBr at 25 and 15°C, HCl at 25, 15, –10, –20, and –30°C).It was found that the nitrosation reaction is a preceeding advance-back-reaction.The velocity coefficients of the nitrosation from bromide (at 15 and 25°C) and from chloride (at 25, 15, –10, –20, and –30°C) were determined. The decomposition of I (splitting off a proton) is the rate determining reaction. The free enthalpies of activation for the nitrosation reaction above bromide and chloride at the said temperatures are calculated (table 3).     

Quantitative determination of phases present in oxidised chalcocite

A sample of chalcocite (Cu₂S) of particle size 45–75 m was heated in air at 10°C min^–1 in a simultaneous TG-DTA apparatus. The phase compositions of the products at various temperatures were quantitatively determined by X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and wet chemical analyses. Copper(II) sulfate, of amount 1.7% by mass, was observed at 435°C and increased rapidly in concentration to 56% at 570°C. From 570–670°C, there was a rapid decrease in CuSO₄ content to 9.8% as the phase converted to CuSO₄·CuO, with the CuSO₄ not being detected at 775°C. From 435–570°C, Cu₂O formed, but at a rather slower rate, reaching 47% at 570°C. The Cu₂O level then decreased to 38% over the range 570–670°C. CuSO₄·CuO was first detected at 570°C by FTIR, although it was not detected by XRD at this temperature. The content of this species reached 41% at 670°C, decreased to 24% at 775°C, and was not detected at 840°C. CuO first appeared at 670°C and rose steadily in concentration until at 840°C it was the only compound present.Dedicated to Prof. Menachem Steinberg on the occasion of his 65th birthday     

Ionization constants of benzoic acid from 25 to 250°C and to 2000 bar

The ionization constant of benzoic acid has been determined by conductivity measurements of dilute aqueous solutions and found to vary from 6.27×10^–5 at 25°C to 0.39×10^–5 at 250°C. The pressure effect to 2000 bar has been measured, and the ratio of ionization constants K₂₀₀₀/K₁ is 2.26 at 25°C and 7.3 at 250°C. V°₁, the standard partial molar volume change for the ionization at 1 bar, varies from –11.7 cm³-mol^–1 at 25°C to –60 cm³-mol^–1 at 250°C. The volume changes are smaller at higher pressures.     

Ionization constants of aqueous ammonia from 25 to 250°C and to 2000 bar

The ionization constant of ammonia has been determined by conductivity measurements and found to vary from 1.77×10^–5 at 25°C to 1.3×10^–6mol-kg^–1 at 250°C. The pressure effect to 2000 bar has been measured and the ratio K₂₀₀₀/K₁ is 6.8 at 25°C and 11 at 250°C. The standard molar volume change for the ionization at 1 bar, V ₁ ^o , changes from –28.8 at 25°C to –67 cm³-mol^–1 at 250°C.