Quantitative kinetic modeling

Small amounts of cyclized products are obtained after the preparation of Grignard reagents from 5-hexenyl bromide.9 This indicates that cyclization of the intermediate radical competes to a small extent with combination of the radical with the metal. Quantitative kinetic models that compare competing processes are consistent with diffusion of the radicals from the surface.10 Alkyl radicals can be trapped with high efficiency by the nitroxide radical TMPO.11 Nevertheless, there remains disagreement about the extent to which the radicals diffuse away from the metal surface.12... 

In most wastes and wastewater, polychlorinated biphenyls (PCBs) and particulate matter are found in the aqueous phase. The fraction of PCBs associated with each phase depends on the hydrophobicity. The congeners containing more chlorine substituents have a stronger tendency to associate with particulate. PCBs sorbed to surfaces such as diatomaceous earth are not oxidized by aqueous OH at an appreciable rate relative to the reaction rate of OH with solution-phase PCBs. Sedlak and Andren (1994) performed a quantitative evaluation of the effect of sorption to particulate matter on the rate of PCB oxidation by OH. The transformations of three PCB congeners — 2-monochlorobiphenyl (MClBp) 2,2, 5-trichlorobiphe-nyl (TrCIBp) and 2,2, 4,5,5 -pentachlorobiphenyl (PeCIBp) — were studied at an initial concentration of 1 pM of PCB solution. Data from the experiments were compared with predictions from quantitative kinetic models that used independently determined data on reaction rates and OH concentrations. 

A quantitative kinetic model of the polymerization of a-pyrrolidine and cyclo(ethyl urea) showed,43 that two effects occur the existence of two stages in the initiation reaction and the absence of an induction period and self-acceleration in a-pyrrolidine polymerization. It was also apparent that to construct a satisfactory kinetic model of polymerization, it was necessary to introduce a proton exchange reaction and to take into consideration the ratio of direct and reverse reactions. As a result of these complications, a complete mathematical model appears to be rather difficult and the final relationships can be obtained only by computer methods. Therefore, in contrast to the kinetic equations for polymerization of e-caprolactam and o-dodecalactam discussed above, an expression... 

Hydrophobic adsorption to sediment particles appears to retard reduction of organic contaminants in anaerobic sediment slurries, so a quantitative kinetic model has been proposed that involves two types of "sites"(168-170),... 

A., et al. BioModels database a free, centralized database of curated, published, quantitative kinetic models of biochemical and cellular systems. Nucleic Acids Res. 2006, 34 D689-D691. 

The previous two cases illustrate situations in which a specific reactant proceeds to a single specific product. More commonly, many products are formed. Accordingly, it is desired to develop quantitative kinetic models that incorporate the necessary elementary reaction pathways to account for the observed products. Furthermore, it is desired to parameterize the elementary steps so that these steps may be applied to related reaction systems under similar conditions. 

In general, a reaction kinetics following a LHHW model is suitable, but the identification of parameters remains demanding. For some catalysts power-law models may be appropriate, for others not. For example, reaction orders identical with stoichiometric coefficients were suitable for Pd/Al203 doped with different metals. On the contrary, for Pd/MgO reaction orders with respect to phenol ranging from -0.5 to 0.5 were observed [17]. However, the bibliographic search was not able to find a quantitative kinetic model for Pd-type catalysts suitable for reactor design. 

Alexander C. M. O D. (2001) Exploration of quantitative kinetic models for the evaporation of silicate melts in vacuum and in hydrogen. Meteorit. Planet. Sci. 36, 255-283. 

A quantitative kinetic model, denominated TC4, for the catalytic conversion of n-butane is proposed. The model considers 56 elementary reactions, six of them were chosen to occur in heterogeneous phase. The TC4 model can be used to predict the product distribution and the heterogeneous rate constants for a wide range of conditions and on different catalyst types. The model can fit also the experimental data from the isobutane dehydrogenation reaction. A plot, that we have denominated "the graphic s performance of a catalyst", is proposed for the evaluation of the maximum yield of a catalyst with a minimum of experimental data. 

In this study, the quantitatively kinetic model for linear block polymerisation up to a high degree of conversion is proposed on the basis of experimental material concerns to kinetics of photoinitiated polymerisation of glycidyl methacrylate (GMA) obtained over a wide range of variation of the available parameters. 

Such idealised conception of two reactionary zones (liquid monomer phase and interphase layer on the boundary liquid monomer-solid polymer ) allowed ns to obtain the quantitative kinetic model of stationary and non-stationary processes for three-dimensional polymerisation and to explain their special peculiarities [23-25]. 

Photo-oxidation of some aaylic-urethane thermoset networks was induced by chromophoric impurities that absorb UV light and produce radicals, initiating a radical oxidation of the polymer [145]. The authors introduced a quantitative kinetic model based on the identified mechanisms and a multi-scale approach from the molecular to the macroscopic level. 

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