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.

Kinetics and mechanism of oxidation of the chromium(III)-DL-aspartic acid complex/periodate reaction. Evidence for iron(II) catalysis

The kinetics of oxidation of the chromium(III)-DL- aspartic acid complex, [CrIIIHL]+ by periodate have been investigated in aqueous medium. In the presence of Fe^II as a catalyst, the following rate law is obeyed:

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

The Second Dissociation Constant of Carbonic Acid in Ethanol–Water Mixtures from 5 to 45°C

The determination of the second dissociation constant of carbonic acid K ₂ in 5, 15, and 25 mass% ethanol—water mixed solvents has been made using cell of the type:

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

Solubility of Rhodochrosite (MnCO3) in NaCl Solutions

The solubility of rhodochrosite (MnCO₃) at 25°C under constant carbon dioxide partial pressure p(CO₂) was determined in NaCl solutions as a function of ionic strength I. The dissolution of MnCO₃(s) for the reaction

The thermal decomposition of zirconium oxyhydroxide

The thermal decomposition of zirconium oxyhydroxides prepared by the mixture of aqueous zirconium oxychloride solutions and aqueous solutions of sodium hydroxide or ammonium hydroxide under various conditions has been examined by thermogravimetry, differential thermal analysis, X-ray diffraction study and infrared spectrophotometry. As a result, it is seen that the thermal decomposition of zirconium oxyhydroxide, in which the composition is ZrO_2-x(OH)_2xyH₂O where x2 and 1y<2, proceeds according to the following process:

Kinetics and mechanism of osmium(VIII)-catalyzed oxidation of hypophosphite by hexacyanoferrate(III) in aqueous alkali

The kinetics of osmium(VIII)-catalyzed oxidation of hypophosphite with hexacyanoferrate(III) in alkaline medium has been studied. The rate is independent of the concentration of the oxidant. The order with respect to hydroxide ion is variable. Rate law (1) conforms with the experimental observations.

Kinetics and mechanism of oxidation of chromium(III)-tetraoxalylurea complex by periodate

A novel chromium(III) complex of tetraoxalylurea was prepared. In aqueous solutions, [Cr^III(H₂L)(H₂O)]⁺ (H₂L = diprotonated tetraoxalylurea) is oxidized by IO ₄ ^– according to the rate law

Vanadium(V) oxidation of thallium(I) in hydrochloric acid

The reaction between V^V and Tl^I was studied in 4.0 mol dm^–3 HCl at an ionic strength of 4.1 mol dm^–3 at 25° C. The main active species under the reaction conditions were found to be VO _inf2 ^sup+ and TlCl _inf3 ^sup2– for the oxidant and reductant, respectively. A probable mechanism in terms of these species is given, and follows the rate law:

Atranes

Complexes of ferratrane-3,7,10-trione (I) of the composition I · H₂O, I · H₂O₂, I · OS(CH₃)₂, and I · 2OS(CH₃)₂ were synthesized. The IR spectra and derivatograms of these compounds were studied.See [1] for communication XXXI.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 164–170, February, 1973.     

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.     

Alkaline hydrolysis of Co(Asn)2 (Asn = l-asparagine)

The kinetics of alkaline hydrolysis of Co(Asn)2, yielding Co(OH)2, NH3 and aspartic acid, have been studied spectrophotometrically, and the effects of CoII and NaOH concentrations on the reaction rate determined. The rate increases with increasing [NaOH], whereas variation of [CoII] has no significant effect. The kinetics of NH3 evolution conform to the rate law:

Thermal properties of Na2TeO4(s) and TiTe3O8(s)

Molar heat capacity measurement on Na₂TeO₄(s) and TiTe₃O₈(s) were carried out using differential scanning calorimeter. The molar heat capacity values were least squares analyzed and the dependence of molar heat capacity with temperature for Na₂TeO₄(s) and TiTe₃O₈(s) can be given as, $$ \begin{gathered} {\text{C}}^{\text{o}}_{{{\text{p}},{\text{m}}}} \left\{ {{\text{Na}}_{ 2} {\text{TeO}}_{ 4} \left( {\text{s}} \right)} \right\} \,={159}.17 { } + 1.2\,\times\,10^{-4}T-{55}.34\,\times\,10^{5}/T^{2};\hfill \\ C^{\text{o}}_{{{\text{p}},{\text{m}}}} \left\{ {{\text{TiTe}}_{ 3} {\text{O}}_{ 8} \left( {\text{s}} \right)} \right\}\,=\,{ 275}.22{ }+{4}.0\,\times\, 10^{-5}T-{58}.28\,\times\,10^{5}/T^{2};\hfill \\ \end{gathered} $$ From this data, other thermodynamic functions were evaluated.     

Atranes

A method of synthesizing hitherto unknown 1-aroxysilatranes (R=aryl) is worked out. It is based on transesterification of lower tetraalkoxysilanes with an equimolecular mixture of triethanolamine and the appropriate phenol (naphthol). Using the method, 12 compounds of the indicated type have been prepared and characterized, the yields in the main exceeding 90%.For Part VII see [1].     

Dissociation Constants for Citric Acid in NaCl and KCl Solutions and their Mixtures at 25 °C

The constants for the dissociation of citric acid (H₃C) have been determined from potentiometric titrations in aqueous NaCl and KCl solutions and their mixtures as a function of ionic strength (0.05–4.5 mol-dm^–3) at 25 °C. The stoichiometric dissociation constants (K_i^*)

Paradigms and Paradoxes: Diazomethane and Ethyl Diazoacetate: The Role of Substituent Effects on Stability

Diazomethane and ethyl diazoacetate are highly reactive and highly versatile synthetic reagents that undergo numerous related reactions. However, while the former is highly dangerous because of its toxicity and explosive behavior; the latter is much more benign. This is usually ascribed to resonance stabilization in ethyl diazoacetate involving an extra carbonyl group that is absent in diazomethane, cf. $$\begin{gathered} {\text{EtOOC}}---{\text{CH}} = {\rm N}^ + = {\rm N}^ - \leftrightarrow {\rm E}{\text{tOOC}}---{\text{CH}}^ - ---{\text{N}}^{\text{ + }} \equiv {\text{N}} \leftrightarrow {\text{EtOC(O}}^ - {\text{)}} = {\text{CH}}---{\text{N}}^{\text{ + }} \equiv {\rm N} \hfill \\ {\text{CH}}_{\text{2}} = {\rm N}^ + = {\rm N}^ - \leftrightarrow {\text{CH}}_{\text{2}}^ - ---{\text{N}}^{\text{ + }} \equiv {\rm N} \hfill \\ \end{gathered}$$ The additional resonance stabilization is derived using a recent literature measurement of the enthalpy of an ethyl diazoacetate/aldehyde reaction, key enthalpies of formation, also from the literature, and some simplifying assumptions. The resonance stabilization is deduced to be but 16 kJ/mol, merely 4 kcal/mol. But, oh how grateful we are for this!     

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:

An investigation of the critical liquid-vapor properties of dilute KCl solutions

The three parameters that define the critical point, temperature, pressure, and volume have been experimentally determined by means of filling studies in a platinum-lined system for five KCl solutions ranging from 0.006 to 0.568m. The platinum-lined vessels were used to overcome the problems with corrosion experienced by earlier workers. The critical temperature (t _c), pressure (P _c), and volume (V _c) were found to fit the equations $\begin{gathered} {\text{t}}_c = 374.14{\text{ }} + {\text{ }}16.602\sqrt {\text{m}} {\text{ }} + {\text{ }}41.740{\text{m }} \pm 0.5^ \circ C \hfill \\ {\text{P}}_c = 220.9 {\text{ }} + {\text{ }}135.164{\text{m }} + {\text{ }}41.173{\text{m}}^{\text{2}} {\text{ }} \pm {\text{ }}0.5 bars \hfill \\ {\text{V}}_c = 3.155{\text{ }} - {\text{ }}1.373\sqrt m {\text{ }} + {\text{ }}0.507{\text{m }} \pm {\text{ }}0.008cm^3 - g^{ - 1} \hfill \\ \end{gathered} $ from infinite dilution to 1.0m.     

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;