Intrinsic kinetic constants

TABLE 13.5. Intrinsic kinetic constant (mol/s molsutface Pd ) and kinetic selectivity rfor different catalysts after reduction at 200°C. 

In the results presented in Table 13.5, the addition of tin affects the kinetic selectivity r differently, depending on the catalyst preparation method. When compared to the monometallic PdO catalyst, r slightly decreases for the coimpregnated PdSn catalyst, but it sharply increases for the PdOSn catalyst prepared via the colloidal oxide synthesis. As the intrinsic kinetic constant rates k do not show significant discrepancies between the different catalysts, the main contribution of the variation of the kinetic selectivity is ascribed to the adsorption constant ratio fBo/ Butenes- In the case of the PdOSn catalyst, formation of but-l-ene is favored compared to its consumption because the X Bo/ Butenes ratio increases, indicating that olefin adsorption is much more destabilized than diene adsorption. Thus, the olefin easily desorbs before being hydrogenated into butane. 

In the case of isolated particles, the kinetic selectivity increases with the reduction temperature (Fig. 13.35). In this case, the TfBD. K Butenes ratio remains almost constant, but the intrinsic kinetic constants relative to the hydrogenation and double bond... 

Figure 13.2 Dependence of the intrinsic kinetic constant kc ofde-NO, and SO2 oxidation reactions (full squares and circles, respectively) on the V content of the catalyst. T = 350 °C, fede-NO, (Nmh ) fesOi-SOi (s )- Adapted from ref. [28]...

Intrinsic kinetic constants Vj j =10 mmol.mg proC min and Kj =200 mM Enzyme concentration=24 mg prot./g support Effective diffusivity, Dgg. 3.10 m2.s ... 

The heterogeneous model of this section is used to extract the intrinsic kinetic constants from the industrial data. The iteration scheme to find these constants is as follows. 

Rodriguez M, Malato S, Pulgarin C, et al. Optimizing the solar photo-Fenton process in the treatment of contaminated water. Determination of intrinsic kinetic constants for scale-up. Solar Energy 2005 79 360-8. 

All rate constants in Equation (11) represent apparent constants. The intrinsic kinetic constant can be calculated using the following relationship (Salaices et al., 2004 Wolfrum and Turchi, 1992) ... 

Stefuca et al. (1990) proposed an ET method offering a rapid, convenient, and general approach to determine kinetic constants of immobilized biocatalysts. Here, a differential reactor (DR) was used for the measurement of the initial reaction rate of sucrose hydrolysis (Vallat et al. 1986). The enzyme column of the ET has been considered as a differential packed-bed reactor, and with a mathematical model, intrinsic kinetic constants of immobilized invertase were calculated from experimental DR and ET data. 

Either as a model composed of single-events number and intrinsic kinetic constants (see above). 

The estimated model parameters are given in table 1. Note that the estimated model parameters cannot be considered to represent intrinsic kinetic constants. They represent lumped parameters which can be disguised by possible heat and mass transfer effects which are not accounted for in the model. 

Tables 5.2 and 5.3 report the values of the regressed parameters, the standard deviations and the individual 95% confidence intervals for the 300 /rmole and 155 /trmole L initial concentrations of phenol. The values of the intrinsic kinetic constants are reported in the last column of these tables.

Numerical solution of the set of equations (7-1) and (7-2) enables the evaluation of intrinsic kinetic constants and subsequently, the calculation of P7 Fand quantum yield... 

Benaiges MD, Sola C, de Mas C (1986) Intrinsic kinetic constants of an immobilized glucose-isomerase. J Chem Tech Biotechnol 36 480-486... 

In these equations ji is the intrinsic kinetic constant and IQ are the adsorption constant of component i. Considering that the hydrogen is present in large excess and its partial pressure is almost constant in all the experiments (0.43 MPa), equations [1] and [2] can be rearranged ... 

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