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1.
The equilibrium constant for the hydrolytic disproportionation of I2
has been determined at 25°C and at ionic strength 0.2 M(NaClO4) in buffered solution. The reaction was followed in the pH range where the equilibrium concentration of I2, I–, and IO3
–are commensurable, i.e., the fast equilibrium
is also established. The equilibrium concentrations of I2and I3
–were determined spectrophotometrically, and the concentrations of all the other species participating in process (1) were calculated from the stoichiometric constraints. The constants determined are \log K_1 = -47.61\pm 0.07 and \log K_2 = 2.86 \pm 0.01. 相似文献
2.
Jia-Zhen Yang Dian-Zhen Lu Hong-Chang Li Chao-Jun Hou 《Journal of solution chemistry》2003,32(6):559-567
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:
at 5 to 45°C. From these data, thermodynamic quantities, dissociation enthalpy, and dissociation entropy were determined. The dependence of pK
2 on dielectric constant of the mixed solvents is discussed in term of the Beveridge model. 相似文献
3.
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.
The rate law deduced from the reactions (i)–(iv) is given by Equation (v) considering that [H+] K
a.
The reaction (iii) is a combination of the following reactions:
The activation parameters for the reactions (ii) and (iii) are consistent with an outer-sphere electron transfer mechanism. 相似文献
4.
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]. 相似文献
5.
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
相似文献
6.
S. S. Nikol'skii 《Theoretical and Experimental Chemistry》1967,1(4):305-308
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
7.
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 ZrO2-x(OH)2xyH2O where x2 and 1y<2, proceeds according to the following process:
8.
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. 相似文献
9.
Hemlata V. Khadilkar S. M. Bhojane Jayanthi Kulkarni S. G. Kulkarni 《Journal of Thermal Analysis and Calorimetry》2013,111(1):939-942
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. 相似文献
10.
Molecular routes to metal oxides has become an area of intensescientific interest due to the technological relevance of thesematerials. Molecular routes are proving important as a result ofthe possibility to control the physical and chemical propertiesof the final materials.We have chosen to study non-hydrolytic methods, namely esterelimination reactions between two prototypical molecularprecursors metal alkoxides, M(OR)n, and metal carboxylates, M(O2CR)n, to synthesize metal oxides:
This method allows for the synthesis of pure metal oxides bycomplete elimination of the organic supporting ligands withconcomitant formation of M-O-M bridges.Furthermore, incomplete esterelimination can lead to isolation of molecular clusters asintermediates which can also be used as building blocks for theformation of metal oxides with controlled microstructure.Here we report a series of reactions between Sn and Si alkoxidesand carboxylates designed to gain further insight into thefactors governing ester elimination reactions. By choosingcompounds with varying coordination environments and stericaccessibility we have devised a set of criteria which shouldallow for successful ester elimination between metal alkoxide andcarboxylate compounds. Furthermore we have also shown theability of ester elimination derived molecular clusters withspecific microstructure to be used in the synthesis of bulkmaterials retaining the structural attributes of the precursor cluster. 相似文献
11.
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. 相似文献
12.
Abdel-Khalek Ahmed A. Mohamed Adel A. Ewais Hassan A. 《Transition Metal Chemistry》1999,24(2):233-238
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 FeII as a catalyst, the following rate law is obeyed:
13.
M. G. Voronkov S. V. Mikhailova V. A. Pestunovich D. É. Zaruma I. V. Zuika 《Chemistry of Heterocyclic Compounds》1972,8(5):548-556
Methods were developed for the preparation of the previously unknown heterocyclic, chelate, mixed anhydride of molybdic and aminotriacetic acids [HOOCCH2
oO2 and its salts. The structures of these compounds in the crystalline state and in aqueous solution were established by IR and PMR spectroscopy, thermography, and potentiometric titration.See [1] for communication XXVII.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 606–615, May, 1972. 相似文献
14.
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
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