Pulverized coal plasma gasification

A number of experiments on the plasma-vapor gasification of brown coals of three types have been carried out using an experimental plant with an electric-arc reactor of the combined type. On the basis of the material and heat balances, process parameters have been obtained: the degree of carbon gasification (_c), the level of sulfur conversion into the gas phase (_s), the synthesis gas concentration (CO+Hz) in the gaseous products, and the specific power consumption for the gasification process. The degree of gasification was 90.5-95.0%, the concentration of the synthesis gas amounted to 84.7–85.7%, and the level of sulfur conversion into the gas phase was 94.3–96.7%. Numerical study of the process of plasma gasification of coals was carried out using a mathematical model of motion, heating, and gasification of polydisperse coal particles in an electric-arc reactor of the combined type with an internal heat source (arc). The initial conditions for a conjugate system of nonlinear differential equations of the gas dynamics and kinetics of a pulverized coal stream interacting with the electric arc and oxidizer (water vapor) agree with the initial conditions of the experiments. The computation results satisfactorily correlate with the experimental data. The mathematical model can be used for the determination of reagent residence time and geometrical dimensions of the plasma reactor for the gasification of coals.Nomenclature c _i volume concentration of components (kmol m^–3) - x longitudinal coordinate (m) - f _i source members, determined by variation of the ith component due to chemical reactions in unit volume in unit time (kmol m^–3s^–1) - velocity (m s^–1) - M _s ash mass in one particle (kg) - C _D particle drag coefficient - 3.14 - r _s particle radius (m) - d particle diameter (m) - density (kg m^–3) - C _p heat capacity of components (J mol^t– K^–1) - Q _j thermal effect of reaction (J kmol^–1) - E_j activation energy of reaction - N _l volume concentration of particles of thelth fraction (m^–3) - T temperature (K) - emissivity factor of coal particles - 5.67 × 10^–8, blackbody emissivity coefficient (W m^–2 K^–4) - P pressure (Pa) - S reactor cross section (m²) - D reactor diameter (m) - V reactor volume (m³) - L _R reactor length (m) - F _W friction force on the wall (N) - f _g friction coefficient - residence time (s) - Nu Nusselt number - Re Reynolds number - Pr Prandtl number - thermal conductivity of gas (J m^– s^–1 K^–1) - R 8.3 × 10³, universal gas constant (J kmol K^–1) - µ _i molecular mass of component (kg kmol^–1) - dynamic viscosity coefficient of gas (kg m^–1 s^–1) - thermal efficiency of plasma reactor - q_arc specific heat flow from arc (W m^–3) - P ₁ heat supplied in vapor at T = 405 K (W) - P ₂ heat loss to wall (W) - P ₃ heat loss in the gas and slag separator chamber (W) - P ₄ heat loss in the synthesis gas oxidation chamber (W) - P ₅ heat loss in the slag catcher (W) - P ₆ heat carried away in the off-gas (W) - P heat input of arc (W) - P _arc electric power of arc (W) - Q_sp specific power consumption (kw Hr kg^–1) - d _w specific heat flow to wall (W m^–2) - _c degree of carbon gasification (%) - _s level of sulfur conversion into gas phase (%)     

Das amphotere Verhalten von Titan(IV)-chlorid in Phosphoroxychlorid

Zusammenfassung Konduktometrische und potentiometrische Titrationen zeigen, daß TiCl₄ in POCl₃ sowohl 2 Chloridionen aufnehmen als auch ein Chloridion abgeben kann. Die Existenz der Koordinationsformen [TiCl₆]^2–, [TiCl₅]^– _solv, (TiCl₄)_solv und [TiCl₃]⁺ _solv läßt sich nachweisen. Das Verhältnis von Donor-und Akzeptorstärke ist von der Konzentration abhängig; in verd. Lösungen ist TiCl₄ vor allem Donor, in konz. Lösungen Akzeptor.Mit 6 AbbildungenZugleich 21. Mitt. der Reihe: Das Solvosystem Phosphoroxychlorid.20. Mitt.:M. Baaz, V. Gutmann undL. Hübner, J. Inorg. Nucl. Chem., im Druck.     

A study of chromic oxide decomposition in an RF argon plasma

Vapor-phase thermal decomposition of chromic oxide in an rf argon plasma was studied using a new experimental system. Homogeneous and heterogeneous modes of reaction were compared, the overall process efficiency being substantially higher for the process carried out entirely in the vapor phase. Reaction products were collected along the reactor wall and studied by chemical methods as well as SEM, X-ray, and IR absorption. The collected powder was highly reactive, fine-grained, and of semiamorphous nature, the average particle size being well below 100 nm. Temperature profiles recorded below the coupling coil by spectroscopic methods were typical of an rf plasma, showing maxima slightly exceeding 5000 K, with the presence of off-axis peaks. Local Cr contents and concentration ratio (Cr)/(Cr₂O₃) in the plasma were determined from the deposition data obtained. A diffusion process was assumed for the wall-deposit buildup. The results obtained confirmed the advantages of using plasma vapor-phase systems, these being higher-efficiency processes and more reliable models than those obtained in the case of gas-solid plasma reactors, where solid particles are injected into the plasma. The thermal decomposition conversion of Cr₂O₃ into Cr was about 8 times higher in the homogeneous gas phase than in the plasma solid phase, all other conditions being equal.Nomenclature c velocity of light, cm × s^–1 - C _Cr ^m metallic Cr content, % by wt. - C _Cr ^t total Cr content, % by wt. - D species diffusivity, cm² · s^–1 - E energy of excited level, eV - f oscillator strength - F rate of species deposition, mol · cm^–2 · s^–1 - g statistical weight - h Planck's constant, J · s^–1 - I radial emission intensity for a given spectral line at a given radius in the plasma, W · sr^–1 · cm^–3 - k Boltzmann's constant, J · K^–1 - l length of collected deposit, cm - m mass of collected deposit, g - M molar weight of Cr - M _Ar ^a molar flow of axial argon, mmol · s^–1 - M _Ar ^p molar flow of peripheral argon, mmol · s^–1 - M _{Cr 2}O₃ molar flow of evaporated Cr₂O₃, mmol · s^–1 - Cr(I) concentration, cm^–3 - Q _T partition function at temperatureT - r reaction radius, cm - R radius of quartz tube, cm - t duration of deposition, s - T temperature, K - total extent of Cr₂O₃ decomposition into Cr, % - Z position of a plane normal to the plasma axis downward the lower turn of rf coil, cm Greek Letters molar ratio of Cr and Cr₂O₃ in deposit - wavelength, nm - species concentration, mol · cm^–3     

Influence of chloride anions on the electrodeposition and electroactivity of the polymer matrix in polypyrrole,poly(<Emphasis Type="Italic">N</Emphasis>-methylpyrrole) and polypyrrole derivatives functionalized by titanocene centers,in dry non-aqueous solutions

We report electrochemical studies on the influence of a small concentration of chloride ions on the electroactivity of the polymer matrix of polypyrrole (PPy), poly(N-methylpyrrole) [p(N-MePy)] and a poly(titanocene-propyl-pyrrole) derivative, p(Tc3Py) [Tc(CH₂)₃NC₄H₄; Tc=CpCpTiCl₂; Cp=C₅H₅; Cp=C₅H₄] in acetonitrile (AN), tetrahydrofuran (THF) and N,N-dimethylformamide (DMF). The polymer films were obtained on Pt disc electrodes from AN solutions of the monomers containing 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF₆) as the supporting electrolyte and then transferred to the corresponding monomer-free solution. Studies in Cl^–-containing solutions have shown that the p(Tc3Py) matrix is very sensitive to the presence of Cl^– ions in all the above solvents, namely that it was subjected to electrochemical degradation at potentials above 0.1 V vs. a Ag/0.01 M Ag⁺ in AN reference electrode. Degradation of the p(Tc3Py) matrix was also observed in chloride-free DMF+TBAPF₆ solutions. Addition of chloride ions to the AN solution containing pyrrole, N-methylpyrrole or Tc3Py inhibits the deposition of the polymer films. On the other hand, we have found that PPy and p(N-MePy) matrices after their deposition in chloride-free AN solutions show much more stable redox responses in contact with chloride and/or DMF solutions. Possible mechanisms of these effects are discussed.Abbreviations AN acetonitrile - Cp cyclopentadienyl - DMF N,N-dimethylformamide - N-MePy N-methylpyrrole - p(N-MePy) poly(N-methylpyrrole) - PPy polypyrrole - p(Tc3Py) poly[Tc(CH₂)₃NC₄H₄] - Py pyrrole - Tc titanocene=bis(cyclopentadienyl)titanium dichloride, Cp₂TiCl₂, or its radical CpCpTiCl₂ (Cp=C₅H₄) - Tc3Py titanocene-propyl-pyrrole, Tc(CH₂)₃NC₄H₄ - THF tetrahydrofuran Contribution to the 3rd Baltic Conference on Electrochemistry, Gdansk-Sobieszewo, Poland, 23–26 April 2003Dedicated to the memory of Harry B. Mark, Jr. (28 February 1934–3 March 2003)     

Determination of Phenol in Surface Waters by High-Performance Liquid Chromatography with Sorption Preconcentration

The retention of phenol and its derivatives on Silasorb C₈ and PepRPC ^TMHR 5/5 was studied. Both columns are suitable for the separation of pyrocatechol–phenol–o-cresol(p-cresol)–2,6-xylenol mixtures using mobile phases containing 10–20 vol % of isopropanol and 1% glacial acetic acid in water. A procedure was developed for determining phenol with a detection limit of 4 mg/L (acetonitrile; signal-to-noise ratio, 2; loop volume, 25 L). With preconcentration from 1-L samples in a Diapak-phenol/P cartridge, the procedure allows phenol to be determined in water samples with a detection limit of 4 g/L. The procedure was used in analyses of samples of river and tap water.     

An Ab Initio Molecular Orbital Theory and Density Functional Theory (DFT) Study of Conformers and Rotamers of 4-Substituted (Methyl, Hydroxymethyl, Methanoyl, Ethanoyl, Cyano, Fluoro, Chloro, Bromo, Acetoxy) Tetrahydro-2H-thiopyran-1,1-dioxides

The structures and energies of axial and equatorial conformers and rotamers of 4-substituted tetrahydro-2H-thiopyran-1,1-dioxides (tetrahydrothiopyran-1,1-dioxides, thiacyclohexane-1,1-dioxides, thiane-1,1-dioxides, and 1,1-dioxothianes; CH₃, CH₂OH, CHO, COCH₃, CN, F, Cl, Br, and OCOCH₃) were calculated using the hybrid density functionals B3LYP, B3P86, and B3PW91, as well as MP2 and the 6-31G(d), 6-31G(2d), 6-31G(3d), 6-31G(d,p), and 6-31+G(d) basis sets. MP2/6-31+G(d)/ /HF/6-31+G(d) [–G° = 1.73 kcal/mol], B3P86/6-31G(d) [–G° = 1.75 kcal/mol], and B3PW91/6-31G(d) [–G° = 1.85 kcal/mol] gave conformational free energy (G°) values at 180 K for 4-methyltetrahydro-2H-thiopyran-1,1-dioxide which were similar to the reported experimental values for methylcyclohexane (–G° = 1.80 kcal/mol), 4-methyltetrahydro-2H-thiopyran (–G° = 1.80 kcal/mol), and other 4-methyl-substituted heterocycles. All levels of theory showed that the conformational preferences of the 4-methanoyl (4-formyl), 4-ethanoyl (4-acetyl), and 4-cyano substituents were small. The HF calculations gave conformational free energy (G°) values for 4-chlorotetrahydro-2H-thiopyran-1,1dioxide which were closer to the experimental value than the MP2 and density functional methods. The best agreement with available experimental data for 4-bromotetrahydro-2H-thiopyran-1,1-dioxide was obtained from the HF/6-31G(2d), HF/6-31G(3d), and B3LYP/6-31G(2d) calculations, and, for 4-acetoxytetrahydro-2H-thiopyran-1,1-dioxide, from the HF/6–31G(3d) calculations. The conformational free energies (G°) and relative energies (E) of the conformers and rotamers have been compared with the correspondingly substituted cyclohexanes and tetrahydro-2H-thiopyrans and are discussed in terms of dipole–dipole (electrostatic) interactions and repulsive nonbonded interactions (steric) in the most stable axial and equatorial conformers. The axial S=O bond lengths are shorter than the equatorial S=O bond lengths and the C2–C3 bond lengths in the substituents with carbon-bonded to the ring are shorter than the C3–C4 and C4–C-5 bond lengths. In contrast, the C2–C3 bond lengths in the 4-halogen and 4-acetoxy substituents are longer than the C3–C4 and C4–C-5 bond lengths.     

Solid-Solute Phase Equilibria in Aqueous Solution. XI. Aqueous Solubility and Standard Gibbs Energy of Cadmium Carbonate

The solubilities of CdCO₃ (otavite) in aqueous NaClO₄ solutions have been investigated as a function of ionic strength (0.15 I/mol-kg^–1 5.35, 25°C) and temperature (25°C T 75°C, I = 1.00 mol-kg^–1). A new Chemsage optimization routine was employed to simultaneously evaluate solubility data from this work and other sources, as well as standard electrode potentials determined at different ionic strengths. With the Pitzer equations the solubility constants, , were extrapolated to infinite dilution resulting in log and the ternary ion-interaction parameters ^S_Na,Cd = 0.19 and at 25°C. In addition, the following set of thermodynamic quantities can be derived from the present solubility data for otavite: _f G = –674.2±0.6 kJ-mol^–1; _f H = –755.3±3.4 kJ-mol^–1; S = 93±10 J-mol^–1K^–1. However, the present solubility data are also consistent with a recent determination of the standard entropy of otavite which leads to a recommended set of thermodynamic quantities [_f G (CdCO₃) = –674.2±0.6; _f H (CdCO₃) = –752.1±0.6; S (CdCO₃) = 103.9±0.2].     

LC-APCI-MS-MS methodology for determination of glybenclamide in human plasma

A liquid chromatographic/atmospheric pressure chemical ionization tandem mass spectrometric method (LC-APCI-MS-MS) for the determination of glybenclamide in human plasma is described. Glypizide, an analogue of glybenclamide, was used as internal standard. The analyte was extracted from plasma with diethyl ether/dichloromethane (70:30 v/v). The chromatography uses C₁₈ and 0.01 mol L^–1 acetic acid/acetonitrile (20:80 v/v) as stationary and mobile phase, respectively. Quantitation was preformed by using multiple reaction monitoring (MRM) of the precursor ion (m/z 494.2368.8) and the related product ion (m/z 446.0347.3) using the internal standard method. The analytical curve was linear in the range 1–300 ng mL^–1, and for a 400-L sample of human plasma, the limit of determination of the method was 1 ng mL^–1. The coefficients of variation of the method for intra-assay (within-run precision) and inter-assay (between-run precision) were less than 10%. The method was shown to be suitable for pharmacokinetic studies.An erratum to this article can be found at     

Thermodynamics of the Second Dissociation Constant of N-tris[Hydroxymethyl]-4-amino-butanesulfonic Acid (TABS) from 5 to 55°C

N-tris[Hydroxymethyl]-4-aminobutanesulfonic acid (TABS) has been investigated for the determination of the values of the second dissociation constant, pK ₂, in water at 12 temperatures in the range 5–55°C, including 37°C. This zwitterionic compound is useful as a secondary pH standard in the range of pH (7–9) for physiological applications. The electromotive force (emf) measurements have been carried out using a hydrogen gas electrode and a silver–silver chloride electrode. The values of pK ₂ are fitted as a function of temperature with the following results: pK ₂ = 1671.305/T+14.8737–2.04383 ln T, where T is the thermodynamic temperature in Kelvins. The experimental values of pK ₂ are 8.834 ± 0.0005 and 8.539 ± 0.0004 at 25 and 37°C, respectively. The related thermodynamic quantities, G°, H°, S°, and C _p ° characterizing the dissociation process have been derived from the pK ₂ and its temperature coefficients.     

Surface Properties of Nickel Electrodes in an Alkaline Electrolyte: An Ellipsometry Study

Adsorption of oxygen-containing species (OCS) on a polycrystalline nickel electrode in an alkaline electrolyte is studied by electrochemical and ellipsometric methods in the potential region from hydrogen evolution to oxygen evolution. It is concluded that OCS have stoichiometric composition Ni(OH)₂ up to 1.35 V. The potential of the OCS formation onset, the oxide monolayer thickness, and the surface coverage by OCS in the interval 0 1 are determined. The oxidation and reduction of a nickel oxide layer, repeatedly cycled at 1.35–1.5 V, suggests that this process is chemically reversible and the thickness of the oxide formed at 1.35 V is constant. It is shown that keeping the electrode under open-circuit conditions at 0.7–0.9 V for 10–20 h leads to the formation of nonelectroconducting oxide NiO _z .     

Ramanspektroskopische Untersuchungen an PCl5 II. Das System PCl5—ZrCl4

Raman spectra of some solid and molten PCl₅–ZrCl₄ mixtures have been recorded. ZrCl₆ ^2– complex ions accompanied by at least one more chlorozirconate species are present in the solid as well as in the melt. The newRaman frequencies are attributed to ZrCl₅ ^–, which fundamentals are given and assignment is proposed to be analogous to TiCl₅ ^–. The presence of ZrCl₆ ^2– and ZrCl₅ ^– can be explained by the equilibrium ZrCl₆ ^2–+PCl₄ ⁺ZrCl₅ ^–+PCl₅.

     

Synthesis,crystal structure and reaction of differentially ring-substituted titanocene dichlorides

Summary A new class of differentially ring-substituted titanocene dichlorides of the type CpCpTiCl₂ has been prepared by reacting CpM (M=Li, K; Cp=RC₅H₄) with CpTiCl₃ (Cp=MeOCH₂CH₂C₅H₄). The crystal structure of Cp(PhCEt₂C₅H₄)TiCl₂, the first example, has been determined by x-ray diffraction and refined to a final R factor of 0.0532 for 2304 reflections. The crystal belongs to the monoclinic space group C _2h ⁵ –P2₁/c with unit cell parameters:a 10.205(6),b 13.003(5),c 17.591(9) Å, 101.91(4)°, V=2284 ų, Z=4 and Dc=1.32 g/cm^–3. Replacement of one neomenthyl in bis(neomenthyl-cyclopentadienyl)titanium dichloride by one MeOCH₂CH₂ — raises the e.e. value from 5.8% to 11.2% in the catalytic asymmetric hydrogenation of 2-phenyl-1-butene.     

Quantitative chemical analysis on paper. I

Summary A method has been proposed for the determination of small quantities of Cl^–, SCN^– and I^– in mixtures. The method is based on the use of filter paper evenly impregnated with Ag₂CrO₄. The method permits the determination of 5 to 50g of Cl^–; 15 to 100g of I^– and 10 to 150g of SCN^– with an accuracy of 1.5%.The method may also be used for determination of SCN^– alone.

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Zusammenfassung Ein Verfahren für die Bestimmung kleiner Mengen Chlorid, Rhodanid und Jodid in deren Gemischen wird vorgeschlagen. Es beruht auf der Verwendung eines mit Silberchromat gleichmäßig imprägnierten Filtrierpapierstreifens und ermöglicht die Bestimmung von 5 bis 50g Chlorid,15 bis 100g Jodid und 10 bis 150g Rhodanid mit einer Genauigkeit von 1,5%. Das Verfahren kann auch für die Bestimmung von Rhodanid allein verwendet werden.

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Résumé On a proposé une méthode pour le dosage de petites quantités de Cl^–, SCN^–, et I^– en mélanges. La méthode est fondée sur l'emploi d'un papierfiltre uniformément imprégné d'Ag₂CrO₄. Elle permet le dosage de 5 à 50g de Cl^–, 15 à 100g d'I^– et de 10 à 150g de SON^–, à la précision de 1,5%. On peut aussi utiliser la méthode pour le dosage de SCN^– seul.

     

Glycosides of marine invertebrates. XXVI. Holothurin A from the Pacific Ocean holothurianHolothvria squamifera. Isolation of the native aglycone

The known triterpene tetraoside holothurin A has been isolated from the Pacific Ocean holothurianHolothuria squamifera. By using two independent methods — enzymatic cleavage and two-stage Smith degradation — 22,25-epoxyholost-9(11)-ene-3,12,17-triol, C₃₀H₄₆O₆, which is the native aglycone of holothurin A, was obtained. The structure of the native aglycone has been established on the basis of the results of IR, mass, and PMR spectroscopy.Pacific Ocean Institute of Bioorganic Chemistry, Far Eastern Scientific Center, Academy of Sciences of the USSR, Vladivostok. Translated from Khimiya Prirodnykh Soedinenii, No. 4, pp. 448–451, July–August, 1984.     

Electrostriction of polymethylmethacrylates

Electrostriction of tactic polymethylmethacrylates in response to step-on and step-offdc-fields was investigated in the field strength range from 1 to 5 MV m^–1 at room temperature; one example of electrostriction under sinusoidal field is given.Three principal retardation time regions were found: ₁=1.5 s, ₂=30 s, and ₃=140 s, each field strength independent. The retardation strengths belonging to these electrostrictive processes depend on tacticity.The low frequency limit of the electrostrictive volume compliance for the investigated PMMA is _a =–1.2×10^–15 m² V ^–2 for atactic, _S =–2.3×10^–14 m² V ^–2 for syndiotactic, and _i=–4.5 × 10^–14 m² V ^–2 for isotactic PMMA.Herrn Prof. Dr. F. H. Müller gewidmet.     

Structure,vibrational spectra,and energetic stability of LnX<Stack><Subscript>4</Subscript><Superscript>−</Superscript></Stack> ions (Ln=La,Lu; X=F,Cl, Br,I)

Molecular structure and properties of La and Lu tetrahalide ions LnX ₄ ^– ) are studied by the configuration interaction singles-and-doubles method augmented with quadruple excitation correction (CISD+Q) and by the fourth-order Möller-Plesset perturbation theory with account for single, double, triple, and quadruple excitations (SDTQ-MP4). The atomic inner shells are described by Stevens relativistic effective core potentials. Valence basis sets are augmented with diffuse s-, p-, and polarization d-, f-, and g-functions. The equilibrium configuration of nuclei in LnX ₄ ^– ions was found to be tetrahedral. The equilibrium internuclear distances, quadratic force constants, vibrational frequencies, and IR intensities of LnX ₄ ^– ions are compared with the corresponding parameters of La and Lu trihalide molecules (LnX₃), calculated within the same approximations. Regularities in the behavior of molecular parameters on going along the LnF ₄ ^– LnCl ₄ ^– LnBr ₄ ^– LnI ₄ ^– series and from La compounds to Lu compounds are revealed. Heights of the energy barriers to the LnX ₄ ^– inversion through the square planar structures (T _d D _4h T _d ) are evaluated: 100–110 and 130–150 kJ/mol for LaX ₄ ^– and LuX ₄ ^– , respectively. Enthalpies of dissociation reactions LnX ₄ ^– LnX₃+X^– are calculated and the results obtained are compared with the available experimental data.Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 3, 2005, pp. 218–228.Original Russian Text Copyright © 2005 by Solomonik, Smirnov, Mileyev.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.     

Studies on transition-metal nitrido and oxo complexes. Part VII(1). Substituted nitrido complexes of osmium and ruthenium

Summary Addition reactions of [MNCl₄]^– (M = Os or Ru) with ligands L or L to give [MNCl₄ · L]^– or [(MNCl₄)₂L]^2– (L = pyridine, pyridine-N-oxide,iso-quinoline or DMSO; L = hexamethylenetetramine, pyrazine or dioxan) are described. With NCO^–, [OsNCl₅]^– gives [OsN(NCO)₅]^2– but NCS^– gives a thionitrosyl complex, [Os(NS)(NCS)₅]^2–. Reactions of OsNCl₃(AsPh₃)₂ with pyridine, 1,10-phenanthroline and tertiary phosphites and phosphinites have been studied, as have reactions of triphenylphosphine with OsOCl₄ andtrans- [MO₂Cl₄]^2– (M = Os or Ru). The nitrido-iodo complexes [OsNI₄]^– and OsNI₃, (SbPh₃)₂ are also reported.     

Rf plasma processing of silica

The processing of silica in an rf plasma was studied with a new experimental system, the process being carried out entirely in the vapor phase. SiO and Si were obtained by either thermal decomposition of SiO₂ or reduction by H₂. No other reducing material (which, like C, may become a contaminant) was used. The products were collected along the reactor length and analyzed afterward. Temperatures in the reaction zone were measured spectroscopically. The high reaction rates occurring in the gas phase did compensate for the low residence times. A diffusional model for the buildup of solid reaction products is discussed. Vapor phase plasma reduction of silica with hydrogen proved to be more effective than thermal decomposition and nuch more effective than heterogeneous processing. The efficiency evaluation was made on the laboratory-scale level.Nomenclature c _SiO ^d SiO content, % by wt - c _Si ^t Total Si content, % by wt - cSiO ₂ ^e Experimental SiO₂ content, % by wt - cSiO ₂ ^t Theoretical SiO₂ content, % by wt - D Species diffusivity, cm² · sec^–1 - F Rate of species deposition, mol · cm^–2 · sec^–1 - MSiO₂ Molar flow of SiO₂, mmol · sec^–1 - n Species concentration, cm^–3 - P Anode power, kW - r Reaction radius, cm - R ^* Radius of quartz tube, cm - T Temperature, K - T _av Average temperature, K - USiO ₂ ^t Total extent of SiO₂ decomposition, % - V _Ar ^a Molar flow of axial Ar, mmol · sec^–1 - V _Ar ^p Molar flow of peripheral Ar, mmol · sec^–1 - VH₂ Molar flow of H₂, mmol · sec^–1 - y Molar fraction - Z Position of a plane normal to the plasma axis down the lower turn of rf coil, cm Greek Letters Molar ratio of SiO over SiO₂ in deposit     

Structure of Electrical Double Layer on Liquid Pb–Ga Alloy in Aqueous Electrolytes

A new electrode, which is a liquid Pb–Ga alloy (0.06 at. % Pb), is developed and studied. It is shown that the alloy's double-layer characteristics dramatically differ from characteristics of a Ga electrode and are practically identical to characteristics of a Pb electrode. Hence, the Pb–Ga electrode in fact models electrochemical properties of a liquid Pb electrode. It is established that the metallic capacitance of the Pb–Ga electrode occupies an intermediate position between values of metallic capacitance of Ga and Hg electrodes, provided the metal–water chemisorption interaction is absent and the electrode charge is fixed. Hydrophilicity of the Pb–Ga electrode is substantially lower than hydrophilicity of a Ga electrode and coincides with hydrophilicity of an Hg electrode. It is shown that In–Ga, Cd–Ga, and Pb–Ga electrodes have close values of the electrochemical work function, and the chemisorption potential drop of the solvent in them increases in the series Pb–Ga < In–Ga < Cd–Ga with decreasing distance of closest approach of water molecules to the ionic core of the metal. The absorbability of anions at the Pb–Ga electrode increases in the series BF^– ₄= SO^2– ₄< Cl^–< Br^–< I^–.     

Das Solvosystem Benzoylchlorid, 4. Mitt.: Spektrophotometrische Untersuchungen

Zusammenfassung Das Ausmaß des Chloridionenüberganges von Triphenylchlormethan zu Metallchlorid wurde in Benzoylchlorid spektrophotometrisch ermittelt und ergab folgende Reihung der Cl^–-Akzeptorstärken: SbCl₅FeCl₃>GaCl₃>SnCl₄>BCl₃> ZnCl₂>TiCl₄>SbCl₃>AlCl₃>PCl₅. Die Cl^–-Donorstärken wurden spektrophotometrisch gegenüber Eisen (III)-chlorid untersucht: Et₄NCl>AlCl₃>TiCl₄>SnCl₄>PCl₅>ZnCl₂> SbCl₃>BCl₃>GaCl₃>SbCl₅FeCl₃. Die Unterschiede gegenüber dem Verhalten in Phenylphosphoroxychlorid werden auf die relativ schwächeren O-Donoreigenschaften des Benzoylchlorids zurückgeführt.Mit 4 Abbildungen3. Mitt.:V. Gutmann undG. Schöber, Mh. Chem.88, 404 (1957).