Gas-Phase Kinetic Study of the Prototype Silylene Addition Reaction SiH2 + C2H4 over the Temperature Range 298-595 K. An Example of a Third-Body Mediated Association

1994 ◽  
Vol 98 (20) ◽  
pp. 5303-5309 ◽  
Author(s):  
N. Al-Rubaiey ◽  
R. Walsh
Keyword(s):  
Kinetic Study ◽  
Gas Phase ◽  
Addition Reaction ◽  
Third Body ◽  
Temperature Range

A Kinetic Study of the Reaction between the 2-Ċ3H7 Radical and i-C4H8: Enthalpy of Formation of the (CH3)2CHCH2Ċ(CH3)2 Radical

2004 ◽  
Vol 218 (4) ◽  
pp. 469-478
Author(s):  
László Seres ◽  
Martin Dinse ◽  
Miklós Görgényi
Keyword(s):  
Thermal Decomposition ◽  
Kinetic Study ◽  
Enthalpy Of Formation ◽  
Rate Constant ◽  
Addition Reaction ◽  
Product Analysis ◽  
Temperature Range ◽  
Reversible Addition ◽  
First Time ◽  
The Enthalpy Of Formation

AbstractThe reversible addition reaction2-Ċ3H7 + i-C4H8 ⇔ (CH3)2CHCH2Ċ(CH3)2was studied in the temperature range 491–543K by product analysis in experiments in which 2-Ċ3H7 radicals were generated by the thermal decomposition of azoisopropane. The enthalpy of formation of the radical (CH3)2CHCH2Ċ(CH3)2 was determined, the value obtained being ΔfH° = -21.8 ± 5.2kJ mol-1. From this result, the following group value was deduced: ΔfH°[Ċ–(C)3] = 177.1kJ mol-1. From the latter, ΔfH°(t-Ċ4H9) = 51.6kJ mol-1 was estimated. The rate constant of self-combination of the radical (CH3)2CHCH2Ċ(CH3)2 was determined for the first time: log(k12/(dm3mol-1s-1)) = 7.3.

Interaction of H2O, O2 and H2 with Proton Conducting Oxides Based on Lanthanum Scandates

2019 ◽  
pp. 88-100
Author(s):  
A. S. Farlenkov ◽  
N. A. Zhuravlev ◽  
Т. A. Denisova ◽  
М. V. Ananyev
Keyword(s):  
Water Vapor ◽  
Partial Pressure ◽  
Gas Phase ◽  
Molecular Hydrogen ◽  
Proton Magnetic Resonance ◽  
Partial Pressure Of Oxygen ◽  
Proton Conducting ◽  
Conducting Oxides ◽  
Temperature Range ◽  
Apparent Level

The research uses the method of high-temperature thermogravimetric analysis to study the processes of interaction of the gas phase in the temperature range 300–950 °C in the partial pressure ranges of oxygen 8.1–50.7 kPa, water 6.1–24.3 kPa and hydrogen 4.1 kPa with La1–xSrxScO3–α oxides (x = 0; 0.04; 0.09). In the case of an increase in the partial pressure of water vapor at a constant partial pressure of oxygen (or hydrogen) in the gas phase, the apparent level of saturation of protons is shown to increase. An increase in the apparent level of saturation of protons of the sample also occurs with an increase in the partial pressure of oxygen at a constant partial pressure of water vapor in the gas phase. The paper discusses the causes of the observed processes. The research uses the hydrogen isotope exchange method with the equilibration of the isotope composition of the gas phase to study the incorporation of hydrogen into the structure of proton-conducting oxides based on strontium-doped lanthanum scandates. The concentrations of protons and deuterons were determined in the temperature range of 300–800 °C and a hydrogen pressure of 0.2 kPa for La0.91Sr0.09ScO3–α oxide. The paper discusses the role of oxygen vacancies in the process of incorporation of protons and deuterons from the atmosphere of molecular hydrogen into the structure of the proton conducting oxides La1–xSrxScO3–α (x = 0; 0.04; 0.09). The proton magnetic resonance method was used to study the local structure in the temperature range 23–110 °C at a rotation speed of 10 kHz (MAS) for La0.96Sr0.04ScO3–α oxide after thermogravimetric measurements in an atmosphere containing water vapor, and after exposures in molecular hydrogen atmosphere. The existence of proton defects incorporated into the volume of the investigated proton oxide from both the atmosphere containing water and the atmosphere containing molecular hydrogen is unambiguously shown. The paper considers the effect of the contributions of the volume and surface of La0.96Sr0.04ScO3–α oxide on the shape of the proton magnetic resonance spectra.

Reesterification of ethyl acetate by propanol catalysed by glycidyl methacrylate copolymers containing sulphonic acid groups

1981 ◽  
Vol 46 (8) ◽  
pp. 1941-1946 ◽  
Author(s):  
Karel Setínek
Keyword(s):  
Liquid Phase ◽  
Ethyl Acetate ◽  
Kinetic Study ◽  
Gas Phase ◽  
Nonlinear Regression ◽  
Kinetic Data ◽  
Glycidyl Methacrylate ◽  
Kinetic Equations ◽  
Methacrylate Copolymers ◽  
Styrene Divinylbenzene

A series of differently crosslinked macroporous 2,3-epoxypropyl methacrylate-ethylenedimethacrylate copolymers with chemically bonded propylsulphonic acid groups were used as catalysts for the kinetic study of reesterification of ethyl acetate by n-propanol in the liquid phase at 52 °C and in the gas phase at 90 °C. Analysis of kinetic data by the method of nonlinear regression for a series of equations of the Langmuir-Hinshelwood type showed that kinetic equations which describe best the course of the reaction are the same as for the earlier studied sulphonated macroporous styrene-divinylbenzene copolymers. Compared types of catalysts differ, however, in the dependence of their activity on the degree of crosslinking of the copolymer used.

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