Reaction kinetics
 | Main requirements to the kinetics evaluation methodology |  |
Creation of kinetic model of a reaction (kinetics evaluation) is one of the most complicated stages of the chemical investigation. It involves knowledge in chemical kinetics theory, mathematical and numerical methods, programming, etc. Apparently it is impossible for the researcher to be an expert in such various fields. Therefore, one of the important aims of the methodology and corresponding software is to help on the researcher with efficient application of all these comprehensive methods. Another feature of the problem is that there is a lot of procedures that cannot be completely formalized. Therefore, the methodology should incorporate the mathematical methods and knowledge and intuition of the researcher into unified strategy. Besides, the following special requirements had been raised: - use of complex multi stage kinetic models;
- application of the most relevant up-to-date mathematical methods, specifically methods for numerical integration of stiff systems of ordinary differential equations and efficient non-linear optimization methods for parameters' estimation;
- possibility of simultaneous processing of experimental data obtained using different experimental methods and under different temperature modes.
| Software for kinetics evaluation | |
Methodology of kinetics evaluation is the same for various classes of reactions. But from practical point of view there are many distinctions dealing with the peculiarities of models applied, data management, and final aim of a study. Therefore ChemInform Saint-Petersburg (CISP) Ltd. offers a set of applications precisely adjusted for solving certain problems instead of one universal program that inevitably turns out to be very complicated, clumsy and inconvenient. ForK, DesK, and ReactOp, are intended for evaluation of homogeneous kinetics. The CatKin program is unique tool for evaluating heterogeneous catalytic kinetics. ForK provides creation of formal models based on conversions as state variables. These models are useful when the detailed mechanism of a reaction is unknown and some overall data are only available (heat, gas generation, mass loss, etc.). Multi stage complex formal models can be constructed without any programming. Main limitation of such models is that they can be used only in combination with BATCH reactor for the same reaction mixture as was studied. DesK allows applying more habitual concentration-based models that obey the generalized law of mass action. These models are applicable for BATCH, semi-BATCH, CSTR, Plug Flow reactors functioning in various thermal modes. No programming is required for creation of a model. ReactOp has the same features as DesK. Very important capability of the ReactOp program is that nonstandard (user's defined) kinetic models and reactor schemes can be added by preparing a piece of Fortran code. The CatKin program is unique tool for evaluating heterogeneous catalytic kinetics. CatKin supports a wide range of known heterogeneous catalytic models that can be applied without programming. The possibility is also foreseen to add user-defined models.
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