Thermodynamic quantities for the interaction of SO 4 2− with H+ and Na+ in aqueous solution from 150 to 320°C

The aqueous reactions,

Calibration of conductance cells at various temperatures

Precise conductance measurements on aqueous potassium chloride solutions at 0, 10, 18, and 25°C have been made under various conditions over a concentration range 10^?4?2 mole-dm^?3, yielding the conductance equations $$\begin{gathered} 25^\circ C:\Lambda = 149.873 - 95.01\sqrt c + 38.48c log c + 183.1c - 176.4c^{3/2} \hfill \\ 18^\circ C:\Lambda = 129.497 - 80.38\sqrt c + 32.87c log c + 154.3c - 143.0c^{3/2} \hfill \\ 10^\circ C:\Lambda = 107.359 - 64.98\sqrt c + 27.07c log c + 125.4c - 110.3c^{3/2} \hfill \\ 0^\circ C:\Lambda = 81.700 - 47.80\sqrt c + 20.60c log c + 93.8c - 79.3c^{3/2} \hfill \\ \end{gathered} $$ which are proposed for calibration of conductance cells.     

Kinetics of substitution of aquo ligands fromcis-diaquo-bis-(biguanide) cobalt(III) and chromium(III) ions by aspartic acid in ethanol—water mixtures

The kinetics of substitution of aqua ligands fromcis-diaqua-bis(biguanide)cobalt(III) and chromium(III) ions by aspartic acid in EtOH–H₂O media have been studied spectrophotometrically in the 30 to 45°C range. We propose the following rate law for the anation

Die Kristallstruktur des Chromarsenids Cr4As3

The crystal structure of Cr₄As₃ has been determined by single crystal photographs: $$\begin{gathered} space group Cm - C_s ^3 \hfill \\ \alpha = 13.16_8 {\AA} \hfill \\ b = 3.54_2 {\AA} \hfill \\ c = 9.30_2 {\AA} \hfill \\ \beta = 102.1_9 \circ \hfill \\ \end{gathered}$$ Cr₄As₃ crystallizes with a novel structure type, which can be derived from the MnP-structure type.     

Enzymatic mechanisms and electron transfer mediation in chronoamperometric biosensors

Electron transfer mediation to an anode, whose potential is judiciously controlled, provides the conceptual basis for the development of novel chronoamperometric biosensors. The mediators are appropriately selected redox couples (Ox/Red) which are amenable to recycling in the following type of enzyme E catalyzed reaction sequence

Structure of products of the addition of methane- and ethane-sulfenyl chlorides to acrylic acid derivatives

Conclusions When alkanesulfenyl chlorides are added to acrylic derivatives CH₂=CHR (R=COOH, COOCH₃, COOCH₃ CN, CONH₂ a mixture of the isomers and is formed and the proportions of these depend on the nature of the substituent R.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1069–1075, June, 1966.     

Interpolation of parameters of solutions expressed as functions of composition

The number of parameters in the polynomial is discussed for N components and a polynomial extending up to power n. This number is found to be but may be N less for relative thermodynamic functions. The equation of degree n for an N-component system requires the use of data for each of the i-component systems. Data on the n-component systems suffice if n相似文献   

Substitution of aqua ligands fromcis-diaqua-bis(bipyridyl) ruthenium(II) by 1, 10-phenanthroline in aqueous medium

The kinetics of aqua ligand substitution fromcis-[Ru(bipy)₂(H₂O)₂]²⁺ by 1, 10-phenanthroline (phen) have been studied spectrophotometrically in the 35 to 50°C temperature range. We propose the following rate law for the reaction within the 3.65 to 5.5 pH range:

Investigations of the distribution of elements in phases present in G-AlMg5Si cast alloy with EDX/WDX spectrometers and AES

Summary The mechanical properties of the most aluminium alloys depend strongly on their chemical composition, casting methods and the heat treatment. Alloys of the type G-AlMg₅Si are known for good corrosion resistance and mechanical properties at elevated temperatures. Under the trade mark Hydronalium (Hy 511) they are used for the production of cylinder heads for air-cooled Diesel engines. To obtain better chemical characteristics, titanium is added to the alloy. This paper deals with the results obtained during investigations about the distribution of elements in the binary eutectic Mg₂Si and the ternary eutectic as well as with the distribution of titanium in samples of Hy 511, obtained during casting of cylinder heads. Studies of the distribution of the elements were performed using EDX/WDX spectrometers, and the distribution of titanium was studied also with Auger electron spectroscopy.     

Critical evaluation and experimental determination of the nuclear activation and decay parameters for the reactions:50Cr(n, ψ)51Cr,58Fe(n, ψ)59Fe,109Ag(n, ψ)110mAg

Isotopic abundance values for⁵⁰Cr,⁵⁸Fe and¹⁰⁹Ag and the absolute gamma-intensities for⁵¹Cr,⁵⁹Fe and^110mAg were evaluated. These evaluated data, together with experimental k₀-determinations (i.e. from the “activation method”), made it possible to calculate the following 2200 m.s^?1 cross-sections, which considerably deviate from the hitherto generally published ones [between brackets]: $$\begin{gathered} {}^{5 0}Cr(n,\gamma )^{5 1} Cr; \sigma _0 = (15.2 \pm 0.2) barn [cf.:15.8 - 16.0] \hfill \\ {}^{5 8}Fe(n,\gamma )^{5 9} Fe; \sigma _0 = (1.31 \pm 0.03) barn [cf.:1.14 - 1.16] \hfill \\ {}^{1 0 9}Ag(n,\gamma )^{1 1 0 m} Ag;\sigma _0 = (3.89 \pm 0.05) barn [cf.:4.4 - 5.0] \hfill \\ \end{gathered} $$      

Kinetic study of hydrogen peroxide reaction with hydroxonitrilotri(methylenephosphonato)iron(III) complex

The decomposition of hydrogen peroxide in the presence of hydroxonitrilotri(methylenephosphonato)iron(III), [Fe(NTMP)(OH)^4–], was studied in nitrate media (=0.10–0.26 M) over the 0.2–0.5 mM concentration range for the iron complex and the temperature range 26–40°C. The rate law;

Vacuum ultraviolet absorption spectra of simple amides

Vacuum ultraviolet absorption spectra of six simple amides were measured. It was found that the positions of the firstπ→π ^* transition bands shift appreciably by the substitutions of methyl groups for hydrogen atoms of the NH₂ and\(\begin{gathered} | \hfill \\ H - C = O \hfill \\ \end{gathered} \) groups. A general tendency is that the substitution in the NH₂ group shifts the band toward longer wavelengths, in the\(\begin{gathered} | \hfill \\ H - C = O \hfill \\ \end{gathered} \) group however towards shorter wavelengths. This was explained satisfactorily by considering the nature of the band (intramolecular charge-transfer band) and the hyperconjugation effect of the methyl group.     

Temperature dependence of europium carbonate complexation

The temperature dependencies of europium carbonate stability constants were examined at 15, 25, and 35°C in 0.68 molal Na⁺(ClO ₄ ^? , HCO ₃ ^? ) using a tributyl phosphate solvent extration technique. Our distribution data can be explained by the equilibria $$\begin{gathered} Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuCO_3^ + + 2H^ + \hfill \\ - log\beta _{12} = 9.607 + 496(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + 2H_2 O + 2CO_2 (g)_ \leftarrow ^ \to Eu(CO_3 )_2^ - + 4H^ + \hfill \\ - log\beta _{24} = 21.951 + 670(t + 273.16)^{ - 1} \hfill \\ Eu^{3 + } + H_2 O + CO_2 (g)_ \leftarrow ^ \to EuHCO_3^{2 + } + H^ + \hfill \\ - log\beta _{11} = 1.688 + 1397(t + 273.16)^{ - 1} \hfill \\ \end{gathered}$$      

Parametric analysis of kinetic models. I. The simplest autocatalytic oscillator

A series of mechanisms allowing oscillations and differring in the form of their buffer steps (step 3)

Kinetics and mechanism of oxidation of malonic acid by chromium(VI) in aqueous perchlorate medium

The kinetics of oxidation of malonic acid, studied in aqueous acid perchlorate, conform to the rate law

Thermische Umlagerung von Acetoxy-cyclohexadienonen, 2. Mitt.

Zusammenfassung Es wird die Frage untersucht, ob bei der thermischen Umlagerung von entsprechend allyl-substituierten o-Benzochinol-acetaten der Allyl- oder der Acetoxylrest rascher wandert. Das 2-Allyl-2-acetoxy-cyclohexadienon liefert bei der genannten Reaktion (es sind schon Temperaturen um 100° ausreichend) überwiegend ein Monoacetat des 4-Allylbrenzcatechins. Damit ist bewiesen, daß der Rest rascher als der Rest in die p-Stellung zur Carbonylgruppe des Chinolacetates wandert. Eine Wanderung des Acetoxylrestes in die o- oder in die p-Stellung zur Carbonylgruppe, welche zur Bildung von 3-Allyl-brenzcatechin bzw. 2-Allylhydrochinon führen müßte, konnte nicht beobachtet werden. Entsprechend liefert das 2,6-Diallyl-2-acetoxy-cyclohexadienon bei der thermischen Umlagerung überwiegend ein Monoacetat des 3,5-Diallyl-brenzcatechins. Nach einem anderen Mechanismus verläuft die Umlagerung des 2-Methyl-6-allyl-2-acetoxy-cyclohexadienons. Es entsteht neben wenig 2-Methyl-6-allyl-hydrochinon in der Hauptmenge ein Monoacetat des 3-Methyl-5-allyl-brenzcatechins. Es wird also die Allylgruppe durch den in die o-Stellung wandernden Acetoxylrest verdrängt. Auf diese Reaktion wird näher eingegangen, weil sie in engem Zusammenhang mit der Frage steht, ob ganz allgemein eine Umlagerung von o-Chinolacetaten vom Typ in die Isomeren möglich ist.Mit 2 AbbildungenHerrn Prof. Dr.F. Feigl zum 70. Geburtstag in alter Freundschaft!F. W. E. Zbiral, F. Wessely undE. Lahrmann, (gilt als 1. Mitt. dieser Reihe), Mh. Chem.91, 331 (1960).     

The pK 2 * for the dissociation of H2SO3 in NaCl solutions with added Ni2+, Co2+, Mn2+, and Cd2+ at 25°C

The pK ₂ ^* for the dissociation of sulfurous acid from I=0.5 to 6.0 molal at 25°C has been determined from emf measurements in NaCl solutions with added concentrations of NiCl₂, CoCl₂, McCl₂ and CdCl₂ (m=0.1). These experimental results have been treated using both the ion pairing and Pitzer's specific ion-interaction models. The Pitzer parameters for the interaction of M²⁺ with SO ₃ ^2? yielded $$\begin{gathered} \beta _{NiSO_3 }^{(0)} = - 5.5, \beta _{NiSO_3 }^{(1)} = 5.8, and \beta _{NiSO_3 }^{(2)} = - 138 \hfill \\ \beta _{CoSO_3 }^{(0)} = - 12.3, \beta _{CoSO_3 }^{(1)} = 31.6, and \beta _{CoSO_3 }^{(2)} = - 562 \hfill \\ \beta _{MnSO_3 }^{(0)} = - 8.9, \beta _{MnSO_3 }^{(1)} = 18.7, and \beta _{MnSO_3 }^{(2)} = - 353 \hfill \\ \beta _{CdSO_3 }^{(0)} = - 7.2, \beta _{CdSO_3 }^{(1)} = 13.8, and \beta _{CdSO_3 }^{(2)} = - 489 \hfill \\ \end{gathered} $$ The calculated values of pK ₂ ^* using Pitzer's equations reproduce the measured values to within ±0.01 pK units. The ion pairing model yielded $$\begin{gathered} logK_{NiSO_3 } = 2.88 and log\gamma _{NiSO_3 } = 0.111 \hfill \\ logK_{CoSO_3 } = 3.08 and log\gamma _{CoSO_3 } = 0.051 \hfill \\ logK_{MnSO_3 } = 3.00 and log\gamma _{MnSO_3 } = 0.041 \hfill \\ logK_{CdSO_3 } = 3.29 and log\gamma _{CdSO_3 } = 0.171 \hfill \\ \end{gathered} $$ for the formation of the complex MSO₃. The stability constants for the formation of MSO₃ complexes were found to correlate with the literature values for the formation of MSO₄ complexes.     

Kinetics and mechanism of oxidation of hydroxylamine by tetrachloroaurate(III) ion

The oxidation of H₂NOH is first-order both in [NH₃OH⁺] and [AuCl₄ ^–]. The rate is increased by the increase in [Cl^–] and decreased with increase in [H⁺]. The stoichiometry ratio, [NH₃OH⁺]/[AuCl₄ ^–], is 1. The mechanism consists of the following reactions.

Cross-sections of 14 MeV neutron reactions on phosphorus and calcium

Cross-section values for 14.7 MeV neutrons are measured for the following reactions: $$\begin{gathered} ^{31} P(n,\alpha )^{28} Al,(132 \pm 10)mb;^{42} Ca(n,p)^{42} K,(173 \pm 19)mb; \hfill \\ ^{43} Ca(n,p)^{43} K,(111 \pm 9)mb;^{44} Ca(n,p)^{44} K,(42 \pm 2)mb; \hfill \\ ^{44} Ca(n,\alpha )^{41} Ar,(27 \pm 2)mb;^{48} Ca(n,2n)^{47} Ca,(616 \pm 54)mb. \hfill \\ \end{gathered}$$ An analysis of available cross-section data for these reactions is performed and preferred mean values for each reaction are given.     

Kinetics and mechanism of anation of hexaaquochromium(III) by 2-aminopyridine

The kinetics of substitution of aqua ligands from the hexaaquochromium(III) ion by 2-aminopyridine (2-ampyH⁺) in aqueous medium has been studied spectrophotometrically in the 40–55° C range. The rate law involving the outer sphere complex formation has been established at pH 2.7 as