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  • Electronic Resource  (12)
Material
  • Electronic Resource  (12)
  • 1
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. The existing empirical and theoretical works on the electronic theory of chemisorption and catalysis do not indicate what type of changes might occur in the catalytic properties of those semiconductors which do not possess d-electrons, if the metalloid anion is varied. 2. The catalytic activity of a binary MeX compound with respect to alcohol dehydration was found to change side by side with the change in bond polarity, which change also shows up in several electrical properties. When the atomic weight of the metalloid in a MeX compound is increased, the alcohol-dehydration activation energy decreases, the dielectric constant increases, the width of the forbidden band and the electronegativity difference decreases. The dependence is complicated by changes in E with the degree of surface covering. 3. On the basis of the literature data, we proposed that the catalytic action of ZnS, ZnSe, and ZnTe (possibly also ZnO) takes place in the range of predominantly intrinsic conduction. A final conclusion will only be reached after the measurements of electrical properties of semiconductors under catalytic conditions have been conducted. We assume that the position of extrinsic (impurity) conduction levels may also depend on the position of the elements constituting the semiconductor in the periodic table.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. A linear relationship was established between the thoron emanation coefficient of magnesium hydroxide and oxide and the specific surface. 2. This relation appears to be valid also for some other systems, and its existence points to the possibility of replacing sorption measurements by the determination of emanation coefficients.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Russian chemical bulletin 8 (1959), S. 561-570 
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. The existence of physical and physicochemical catalysis, along with the usual or chemical catalysis was demonstrated. 2. The main classes and groups of physical and physicochemical catalysis, their peculiarities and significance were discussed.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Russian chemical bulletin 10 (1961), S. 1110-1116 
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. An explanation has been given of some general stastico-kinetic causes, leading to a strong dependence of the preexponential factor in formulas for the rate of activation processes on the activation energy, and the corresponding formulas have been derived. 2. It has been shown that because of the localization of the overwhelming majority of elementary acts of the activation processes in macroscopically small regions possessing “instantaneous” temperature considerably in excess of the mean temperature of the system, and depending on the activation energy, in the expressions for the rate constant a strong relationship is revealed between the preexponential factor and the activation energy. Conditions typical for condensed systems have been established, which favor the appearance of a considerable preexponential factor.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. The production of especially pure substances using new variations of gas Chromatography-thermal displacement, quasi-displacement, and others- was described. 2. The results of the use of the “chromatographic system” for the solution of preparative problems are set forth. The essence of the method consists of the combination of Chromatographic partitioning with a chemical reaction in one apparatus and in one unified process. 3. New chromatographic methods have been developed for the study of the equilibrium system of solid and mixture of gases and vapors and the system of liquid and mixture of gases and vapors. 4. The promising nature of the isotopic chromatography (radiochromatography) developed, as applied to monitoring of the purity of substances produced by chromatographic separation, has been demonstrated.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The tetracyanoquinodimethane complexes of the alkali metals and quinoline do not exhibit catalytic activity in the reactions of propylene hydrogenation and carbon oxidation. 2. The catalytic decomposition of formic acid on the complexes of tetracyanoquinodimethane with alkali metals, which proceeds in both possible directions, namely dehydrogenation and dehydration, is accompanied by a partial destruction of the complexes.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The influence of treatment of a Bi-Mo catalyst with quinoline on the oxidative dehydrogenation and isomerization of isoamylenes was studied by a pulsed chromatographic method. 2. The measured activation energies on poisoned and unpoisoned catalysts indicate an inhomogeneity of the catalytic surface. The logarithm of the relative rate constant of oxidative dehydrogenation drops as a linear function of the amount of poison introduced. 3. Quinoline most strongly suppresses profound oxidation, then oxidative dehydrogenation, and has the least effect on isomerization.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Russian chemical bulletin 10 (1961), S. 713-721 
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. Analysis of the experimental data provides a basis for the supposition that general causes exist which give rise to the profound relationship between the pre-exponential factor and the activation energy. This relationship does not emerge from the theory of absolute reaction rates and the assumptions of Frenkel', which do not take into account the collective character of the movement of interacting particles in a condensed system. 2. Taking account of the collective character of the movement of the particles in a condensed system during the consideration of the elementary act, leads to an exponential relationship between the pre-exponential factor and the activation energy. Analysis of the premises lying at the basis of the relationships obtained, reveals certain possibilities for further communications.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary 1. The reaction between nitrous oxide and cobalt-manganese spinels containing admixed lithium, titanium, and copper oxide has been studied. 2. When the decomposition takes place on a spinel of nearly normal structure, the over-all kinetics are found to be first order, whereas zero order is observed on spinels of reverse or strongly distorted structure. 3. N2O decomposition on spinels is retarded by oxygen present in the gas phase and also by oxygen sorbed by, or penetrated into, the spinel in the course of the reaction. 4. It has been established that the activity of spinels varies symbatically with their capacity to chemisorb oxygen. 5. Decomposition of chemisorbed N2O, or regeneration of active centers, will be the rate-determining step in the catalytic decomposition of nitrous oxide.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Springer
    Russian chemical bulletin 14 (1965), S. 1293-1300 
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. A theoretical analysis shows that under the conditions of Chromatographie separation, chemical reactions of various phase types acquire certain general characteristics-a shift of the equilibria, downward expansion of the temperature region, elimination of a number of side processes. 2. An experimental verification of the conclusions of the theory, with the catalytic dehydrogenation of cyclohexane and butane as an example, using pulsed and radiochromatography, confirmed the correctness of these conclusions.
    Type of Medium: Electronic Resource
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