Geminal systems. 15. Chemical properties of N-chloro-N-alkoxy-N-tert-alkylamines

Conclusions N-chloro-N-alkoxy-N-tert-alkylamines react exclusively with CN^– and SCN^– and partially with Et^– and AcO^– to give nucleophilic substitution products at the nitrogen atom. These compounds react with AcO^– and water to give nitroso compounds, with EtS^– and Ph₃ P to give azoxy compounds, and with AgF and AgNO₃ to give products of more complex transformations.For communication 14, see ref. [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2320–2326, October, 1981.     

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).     

Infrared diode laser spectroscopy of the ν = 2 band of AlF

A vibrational–rotational spectrum of the ν = 2 transitions of a high-temperature molecule AlF was observed between 1490 and 1586 cm⁻¹ with a diode laser spectrometer. Measurements were made on the ν = 3–1, 4–2, 5–3 and 8–6 bands at a temperature of 900 °C. Measured spectral lines were fitted to effective band constants ν₀, B_ν and D_ν for each band. Present measurements were made with only one Pb-salt laser diode. Physical significance of the effective band constants is discussed.     

Aqueous uranyl complexes. 3. Potentiometric measurements of the hydrolysis of uranyl(VI) ion at 25°C

Potentiometric titrations of uranyl(VI) solutions were conducted using a standard glasslcalomel electrode combination over the pH range 3 to 12 at 0.1 molkg^–1 ionic strength with tetramethylammonium trifluoromethanesulfonate as the supporting electrolyte. The electrodes were calibrated directly on the hydrogen ion concentration scale during the initial stage of each titration. The species, UO ₂ ²⁺ , (UO₂)₂(OH) ₂ ²⁺ , (UO₂)₃(OH) ₅ ⁺ , (UO₂)₃(OH) ₇ ^– , (UO₂)₃(OH) ₈ ^2– , and (UO₂)₃(OH) ₁₀ ^4– identified in an earlier Raman study were compatible with the analysis of the titration data. Based on this analysis and application of the extended Debye-Hückel treatment, the polynuclear species indicated above were assigned overall formation constants at 25°C and at infinite dilution of –5.51±0.04, –15.3±0.1, –27.77±0.09, –37.65±0.14, and –62.4±0.3, respectively. The results are discussed in reference to hydrolysis quotients reported in the literature for the first three species. Formation quotients for the last two species have not been reported previously.     

Volumetric properties of dilute aqueous solutions of cobalt-amine-type salts. Part I. Densities at 25°C

The densities of dilute aqueous solutions of [CoL₃]X₃ [L=1,2-diaminoethane(en), 1,2-diaminopropane(pn), 1,3-diaminopropane(tn) X=Cl^–, Br^– and (ClO₄)^–] have been measured at 25°C from 0 to 5×10^–2m. The apparent molar volumes were calculated and extrapolated to infinite dilution. Ion-solvent interactions were detected from the change of the ionic partial molar volumes with concentration. These interactions depend both on the properties of the ion (polarization charge density at the surface, hydrophobic groups, etc.) and the characteristics and structure of the solvent.     

On the role of solvent in complexation equilibiria. II. The acid-base chemistry of some sulfhydryl and ammonium-containing amino acids in water—acetonitrile mixed solvents

The macroscopic and microscopic acid-base chemistry of a series of sulfhydryl and ammonium-containing amino acids HS–R–NH₃ [R=–CH₂CH(COOH)–, cysteine (CYS); R=–C(CH₃)₂CH(COOH)–, penicillamine (PEN); R=–CH(COOH)CH₂CH₂CONHCH(–CH₂)CONHCH₂COOH, glutathione (GSH)] was characterized in water and its binary mixtures with acetonitrile (16.3, 34.2, and 53.9 mass % acetonitrile). Macroscopic acid dissociation constants were obtained by potentiometric titration using the glass-calomel electrode pair. Microscopic acid dissociation constants were calculated from ultraviolet absorption measurements at ca. 232 nm where the deprotonated sulfhydryl group absorbs. The macroscopic constants decrease uniformly as the solvent becomes enriched in acetonitrile. The microscopic constants, which characterize the relative concentrations of the two monoprotonated tautomers of the molecules (I and II) reveal that as the solvent becomes enriched in acetonitrile, the fraction of molecules existing as highly charged tautomer I decreases for CYS (0.68–0.40), PEN (0.85–0.34), and GSH (0.61–0.30). These results are related to the decreasing concentration of water as the solvent becomes enriched in acetonitrile.     

Thermodynamics of aqueous gallium chloride. Apparent molar volumes and heat capacities at 25°C

Apparent molar volumes and heat capacities of aqueous GaCl₃ have been measured at 25°C in binary GaCl₃ solutions up to 3 mol-kg^–1, and in ternary GaCl₃-HCl solutions, containing 0.1345 mol-kg^–1 HCl to suppress hydrolysis, up to a concentration of 1 mol-kg^–1 GaCl₃. Using the Pitzer interaction model for the excess properties, and using ridge regression for the derivation of physically meaningful regression parameters, the measurements yield the following results for the standard molar properties and Pitzer parameters at 25°C: V⁰(GaCl₃)=12.85 cm³-mol^–1; ₀ ^v (GaCl₃)=1.10×10^–4 kg-mol^–1–J^–1–cm^–3; _v ¹ (GaCl₃)=2.12×10^–3 kg–mol^–1–J^–1–cm³; Cv(GaCl₃)=1.34×10^–5 kg²–J^–1–cm³; V^o(GaOHCl₂)=13.84 cm³–mol^–1; C _o ^p (GaCl₃)=–480.8 J–K^–1–mol^–1; _J ⁰ (GaCl₃)=–8.02×10^–6 kg–mol^–1–K^–2; _J ¹ (GaCl₃)=0.73×10^–4 kg–mol^–1–K^–2; C_J(GaCl₃)=–2.52×10^–6 kg²-mol^–2-K^–2; C _p ⁰ (GaOHCl₂)=20.4 J-K^–1-mol^–1. The latter parameter has only mathematical significance, its physical meaning is unclear. Comparison of the present experimental results for the standard molar properties of Ga³⁺ with semi-empirical correlations casts doubt upon the general validity of these correlation methods for trivalent cations.     

Taylor dispersion measurements at low electrolyte concentrations. I. Tetraalkylammonium perchlorate aqueous solutions

An equipment for the determination of mutual diffusion coefficients using the Taylor's dispersion technique is described. The radius of the capillary was determined with the help of various calibration methods. Diffusion coefficients of aqueous tetraalkylammonium perchlorates, Me₄NClO₄, and Et₄NClO₄, were measured at 25°C in the concentration range 10^–3 to 5×10^–2 mol-dm^–3, and the slightly soluble Pr₄NClO₄ up to 1×10^–2 mol-dm^–3. The slope of linear plots ofD vs. is in agreement with theory, in contrast to the limiting valuesD ₀, which all deviate by about –5% from the Nernst-Hartley values.     

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     

Synthetic analogues of Peganum alkaloids. III. Pentamethylenequinazolones

Monosubstituted 5-, 6-, and 8-methoxy-3,4-dihydro-2,3-pentamethylenequinazolones (1–3) have been syntehsized by the condensation of monosubstituted methoxyanthranilic acids with caprolactam. Demethylation with hydrobromic acid gave the corresponding hydroxy compounds [4–6]. When the 6- and 8-methoxy- and 6- and 8-hydroxy-3,4-dihydro-2,3-pentamethylenequinazolones (2, 3, 5, and 6) were reduced with zinc in hydrochloric acid, the corresponding quinazoline derivatives (7–10) were obtained. The melting points of the basis and their hydrochlorides are given. Some features of their UV, mass, and PMR spectra are reported.Institute of the Chemistry of Plant Substances, Academy of Sciences of the Uzbek SSR, Tashkent. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 465–469, July–August, 1986.     

Occurrence and distribution of metals and porphyrins in Nigerian coal minerals

The metal contents of Nigerian coal minerals were analyzed using an atomic absorption spectrophotometer. Calcium, Na, and Fe occurred as the major elements with concentrations ranging from 9 782 μg/g for Ca to 432 μg/g for Na whereas K, Mg, Mn, Ni, Cr, Zn, Pb, and Cu, which occurred at trace levels ranged from 673.73 μg/g for Mg to 2.97 μg/g for Mn. The results of the quantitative analysis of porphyrins extracted from the coal minerals showed that Onyeama coal has the highest amount of porphyrins (ca～0.96 μg/g) while Okpara has the lowest (ca～0.30 μg/g). The porphyrins were qualitatively characterized by a combination of thin layer chromatography (TLC), infrared, and ultraviolet-visible spectrophotometers. The results of the mid infrared analysis (MIR) showed the presence of absorption bands at 3 440 cm～1～3 450 cm-1 and 1 640 cm-1～1 680 cm-1 , which are owing to the stretching vibrations of N - H and C = C of aromatics, with C- H out of plane (oop) bending vibrations at wavenumbers less than 900 cm-1, all of which are characteristic absorptions of porphyrin free base. The ultraviolet-visible data showed prominent peaks at ～400 nm(Soret band) and at wavelength ranges of 535 nm～550 nm(β-band) and 565 nm～ 600 nm (α-band) for the coal porphyrins analyzed. The geochemical significance of the metals and porphyrins in coal minerals are discussed.     

ZnO nanorods decorated calcined Mg–Al layered double hydroxides as photocatalysts with a high adsorptive capacity

The nanocomposites of magnesium–aluminium–carbonate–layered double hydroxides (Mg–Al–CO₃–LDHs) and ZnO nanorods were prepared via a homogeneous precipitation process. The presence of ZnO nanorods made the calcined Mg–Al–CO₃–LDHs, the strong adsorptive adsorbents for anions, have a photocatalytic activity. Both Mg–Al–CO₃–LDHs and the nanocomposites with various ZnO/Mg–Al–CO₃–LDHs mass ratios from 0.5:1 to 3:1 were characterized by X-ray diffraction, transmission electron microscope and UV–vis diffuse reflectance spectra. The nanocomposites quickly adsorbed the anionic dyes such as acid red G (ARG) without the light illumination, and the adsorbed dyes on the recovered nanocomposites were then degraded in a separated photocatalytic reactor. The adsorption ability of the nanocomposites and their photocatalytic activities for the removal of ARG were evaluated by the Fourier transform infrared spectra and UV–vis extinction spectra. The sample at 3:1 ZnO/Mg–Al–CO₃–LDHs mass ratio was shown to have higher photocatalytic efficiencies.     

Kinetics and mechanism of metal ion catalysis. Part III. Osmium(VIII) catalysed oxidation of m-hydroxybenzaldehyde by Fe(CN)6 3− in alkaline medium

Os^VIII-catalysed oxidation of m-hydroxybenzaldehyde by alkaline Fe(CN)₆ ^3– has been studied in the 0.01–0.05 M [OH^–] range. Higher [OH^–] concentrations were not possible as the substrate turned yellow at [OH^–] > 0.05 M. The very low solubility of the substrate in H₂O restricted the kinetic study to [OH^–] < 0.01 M. A mechanism, consistent with the results is proposed.     

E.p.r. evidence for the formation of the six-coordinate pentafluoronitridotechnetate(VI) anion in solution

The reaction of AsPh4[TcNX4] (X=Cl or Br) with naked F– in MeCN solution has been shown by e.p.r. spectroscopy to result in the facile substitution of the halo ligands by fluoride. Addition of six equivalents of NBu4F·3H2O has provided, for the first time, direct evidence for the formation of the six-coordinate [TcNF5]2– in solution. An e.p.r. study of ligand exchange of Cs2[TcNCl5] (4 × 10–2 – 5 × 10–4 mol dm–3) in 28.6 mol dm–3 aqueous HF has shown that the distribution of the five [TcNFnCl4–n]– (n = ;0–4) species is concentration dependent, with the formation of [TcNF4]– being favoured by dilution.     

Photo- and thermochromic spirans. 16. 2-Oxo-3-phenyl-5,5-dimethylspiro(1,3-oxazolidine-4,2′-[2h]chromenes)

New spirans of the 5,5-dimethyl-3-phenyl-2-oxazolidone series that display photo-chromic properties in alcohol solutions at -80 °C were synthesized. The photoinduced forms are characterized by the presence of two long-wave absorption bands at 350–420 nm and 500–650 nm. The ¹H and ¹³C NMR spectra were studied. Anisochronicity of the diastereotopic methyl groups of the oxazolidone ring shows up only in the ¹³C NMR spectra.See [1] for communication 15.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 8, pp. 1031–1035, August, 1985.     

Cu-superconductors in organic catalysis, II. The conversion of benzyl alcohol on various Cu-catalysts

The catalytic conversion of benzyl alcohol to toluene and benzaldehyde was performed on YBa₂Cu₃O_7–x (Y–Ba–Cu–O) in the presence of hydrogen at 250–400°C. The catalytic characteristics of Y–Ba–Cu–O were compared with those of CuO, Cu/SiO₂ and Y₂BaCuO₅. The structural changes in the catalysts during the reaction were measured by means of XRD and SEM. It was found that the oxidation state of the copper in Y–Ba–Cu–O was a considerable factor in the conversion of benzyl alcohol.Part I:React. Kinet. Catal. Lett. 51, 61 (1993).     

Zur Kenntnis der Reaktionsfähigkeit des unsubstituierten Thiomorpholins und alkylsubstituierter Thiomorpholine. 3. Mitt

A new synthesis of thiomorpholine by ring closure of -chloro--aminodiethylene-sulfide with potassium hydroxide is reported. Numerous reactions of thiomorpholine (1) and, especially, 2-methyl-3-ethyl-thiomorpholine (2) are described such as acylation, diacylation (3–43), reactions with sulfonic acid chlorides (44–52), isocyanates (53–61, 70–75), diisocyanates (62–66, 76–78) and isothiocyanates (67–69, 79–82), alkylation reactions (83–111) and the synthesis of thiomorpholino-dithiocarbamates (112–121).

Teil der Dissertation,E. Wilms, Techn. Hochschule Aachen, 1971.     

Effect of preparation pH on pore structure of silica gels

Surface characterization of silica gels prepared at different gelation pH from water glass and sulphuric acid were made by argon adsorption at 77 K using continuous volumetric method. While microporous silica gels prepared in the pH range of 1–3 had BET surface areas of 504–571 m² g^–1, total pore volumes of 0.26–0.31 cm³ g^–1 and micropore volumes of 0.16–0.23 cm³ g^–1, mesoporous silica gels prepared in the pH range of 3.36–0.65 had BET surface areas of 374–530 m² g^–1 and pore volumes of 0.61–0.79 cm³ g^–1.     

The seed oil of Catalpa. I

Summary 1. The fatty-acid compositions of the seed oils of catalpas cultivated in the Soviet Union have been studied.2. The oil content of the seeds is 21.2–36.7%, the refractive index 1.4905–1.5400, and the iodine number 184.8–201.7.3. The following fatty acids have been found in catalpa oil (%): palmitic — 1.3–4.3; stearic — 1.1–2.5; heneicosanoic — 0.5–5.2; oleic — 5.5–9.8; linoleic — 39.6–50.3; linolenic — 0.4–1.8; and eleostearic — 32.8–46.2.4. The most accurate results for characterizing the degree of unsaturation of the fatty acids of the catalpa seed oils are given by Woburn's method of determining iodine numbers. The iodine numbers obtained experimentally agree with those calculated and consequently the addition of halogen to the system of double bonds takes place at all the double bonds.5. The degree of unsaturation of the fatty acids of catalpa oil characterized by the iodine numbers and refractive indices increases in the sequence of species southern, northern, teas, Chinese and has a tendency to rise on passing to more northerly zones, which is one more piece of evidence confirming the correctness of S. L. Ivanov's climatic theory of the structure of fats.Kalinin Polytechnic Institute. Moscow Branch of the All-Union Scientific-Research Institute of Fats. Translated from Khimiya Prirodnykh Soedinenii, No. 3, pp. 331–337, May–June, 1977.     

The determination of losses in the fire assay of gold : Part II. Losses in the complete assay and application of optimal procedures

Losses in the complete fire assay for gold were found to be less than 1% under ideal conditions. The use of polythene bags for mixing each sample was shown to improve both the accuracy and the precision of the assay. Fusion temperatures of 1900°–2300°F and times from 0.5–3.5 h showed only small variations in gold recovery. The optimal conditions were fusion for 1.5–2 h at 2100°F, with a button weight of 18 g, and cupellation at 1800°F. However, the overall assay proved remarkably insensitive to variation in conditions. The need to determine the silver retained in the parted gold beads is emphasized. Gold losses in the procedural stages were established with tracers; the loss to the crucible was most significant. The use of lead foil as a simulated button gives misleading results. For synthetic samples containing 24.5–490 μg of gold, average recoveries were 100% (s=0.6–1.8). Application to two gold ores is discussed.