Authors:Zhong-Suo Liu, Qi Wang, Zong-Shu Zou, and Guang-Lei Tan
(O) is formed, while CO 2 is reduced to CO. Then, C f (O) is broken into CO. This is the slowest step of the reaction. Chen et al. [ 3 ] also proposed a reactionmechanism for carbon gasification. They considered that, in addition to C f , CO 2 is
Authors:Tugba Davran-Candan, Mehtap Demir, and Ramazan Yildirim
activity and selectivity at temperatures near the operating temperature of proton exchange membrane (PEM) fuel cells [ 1 – 5 ]. Despite the extensive research carried out in the field, controversies still remain related to the reactionmechanism and the
Two kinds of compensation mechanism are suggested: a genuine one due to thermodynamic factors and a pseudo one arising from
experimental or data-processing artifacts. It is computationally demonstrated that the choice of reaction mechanism strongly
influences the kinetic parameters determined in thermal analytical studies. It is further shown that the kinetic parameters
determined at different heating rates by using a pseudo reaction mechanism exhibit kinetic compensation that gives the temperature
of the experiment as the so-called isokinetic temperature. A rule of thumb relating to the magnitude of the isokinetic temperature
is suggested to differentiate genuine compensation from pseudo compensation.
Thermogravimetry is often used to study polymer degradation. Most often the information obtained may have some practical application
but is of limited value for the determination of fundamental processes which may be occurring. A kinetic expression or activation
parameters for a complex process which may involve consecutive or parallel reactions provides almost no information about
any of the reactions that might be occurring. However, for single, well-defined processes, thermogravimetry, in conjugation
with other analytical methods, can be effectively utilized in the determination of reaction mechanism. The thermal degradation
of vinylidene chloride barrier polymers corresponds to the elimination of hydrogen chloride initiated at an allylic dichloromethylene
unit in the mainchain. This process is uncomplicated by competing reactions.
Thermogravimetry may be utilized to obtain meaningful rate constants and activation parameters for the degradation. This in
conjunction with mass spectral analysis of evolved gas, characterization of both the polymer and degradation residue by ultraviolet,
infrared and 1H and 13C NMR spectroscopy, and the study of model compounds has permitted a detailed description of the degradation process. General
purpose poly(styrene) is a commodity polymer widely used in the food packaging industry as well as many others. If processed
at excessively high temperature, it undergoes thermal degradation to expel styrene monomer which can impart negative flavor
and aroma characteristics to packaged food items. The degradation reaction has been fully detailed using thermogravimetry
in conjugation with evolved gas analysis, size exclusion chromatography and NMR spectroscopy.
Authors:F. J. Lona-Ramírez, R. Herrera-Muñoz, V. Rico-Ramírez, F. Louvier Hernández, G. Luna-Bárcenas, and G. González-Alatorre
work presents the results obtained from a kinetic study of the nitrosation of 1,1,3-nitrosotrimethylurea, including both the validity of the Arrhenius equation and the reactionmechanism.
The solutions were
Authors:J. Walczak, I. Rychlowska-Himmel, and P. Tabero
The reaction mechanism of the synthesis of Fe8V10W16O85 was studied by means of XRD, IR spectroscopy and DTA techniques. It was found that the intermediate in the reaction may be
either FeVO4 or FeVO4 admixed with an unidentified phase X, depending on the reaction temperature. The IR spectrum of the phase Fe8V10W16O85 is reported for the first time.
Authors:András Németh, Krisztián Stadler, Judit Jakus, and Tamás Vidóczy
formation of • NO 2 by modeling based on a detailed reactionmechanism.
Most of the experimental data are from our already reported work [ 8 ]. Three-week-old male Wistar rats were kept under standard conditions
An established DTA/T/EGD/GC on-line coupled simultaneous technique and relevant equipment were applied to identify the micro
impurity minerals—pyrite and siderite in two kinds of dolomite in air and N2. The proportional five-component mixed minerals (siderite, kaolinite, dolomite, calcite and quartz) and the proportional
six-component mixed minerals (pyrite and the above five minerals) were detected in N2 and in air/CO2 (1∶1) separately by applying DTA/EGD/GC and DTA/GC. The experimental results provide the basis for demonstration of the reaction
mechanism of thermal decomposition of various gas—solid-phase minerals in N2 and air/CO2. The compositions of six-component mixed minerals can be distinguished individually from the DTA/GC curves; reliable results