Deactivation function coefficient

The influence of the coke on the kinetics of the main reaction can be accounted empirically by multiplying the kinetic coefficient of eq. (4) by a deactivation function coke content of the catalyst, Cc ... 

Each rate coefficient in the above equations contains the corresponding deactivation function. This was shown, by experiments on a thermobalance, to be of the exponential type. Furthermore, it was shown that coking and hydrocracking occurred on the same sites so that... 

The preceding discussion emphasizes the applicability of Eq. (6-6) for adsorption onto polar adsorbents, particularly adsorbent samples deactivated by varying amounts of water. However, the derivation of Eq. (6-6) does not preclude its application to nonpolar adsorbents. Claesson has in fact observed 14) the existence of a similar relationship for adsorption onto various charcoals. For the homologous carboxylic acids as samples and ethanol as solvent, the Langmuir isotherm [Eq. (3.6-)] was found to describe the adsorption of each acid. The derived values of the Langmuir coefficient k [or K° in Eq. (3-6)] could be expressed as a function of the number n of carbon atoms in the sample molecule ... 

Figure 4 Profiles of deactivation coefficient, b, as a function of S C ratio for various temperatures...

The rate constants, the adsorption equilibrium constants, and the deactivation parameters a, and oto were determined from the measurement of Pa and pj, as a function of time and position (i.e., W/F o) in the bed, through a special sampling device. In addition, the coke profile was measured at the end of the run. The parameters were found to be statistically significant, and the rate coefficients obeyed the Arrhenius temperature dependence. 

Fluorescent molecules are subject to intensity variations as a function of temperature. In general, the frequency of collisional deactivation with solvent molecules increases as the temperature increases. These collisions bleed energy from the excited state and a fluorescence intensity decrease results. Temperature coefficients are typically 1-2% per °C. A thermostated sample cell is recommended to ensure temperature control both in samples and in standards. 

To account for deactivation of the catalyst by basic nitrogen compounds, the rate coefficients are multiplied by the function... 

The development of metal complexes, particularly those based on nickel, resulted in compounds which exhibited relatively low extinction coefficients in the near ultraviolet region and yet in many instances were found to be superior in performance to the currently available ortho-hydroxyaromatic compounds [3,5]. This finding resulted in a search for some other feasible mechanistic function. As carbonyl photolysis was considered to be an important initiation process which gives rise to both free radicals and backbone cleavage, then deactivation or quenching of the excited-state precursor should prove an effective means of photoprotection. Effective structures in this respect were tris(dibenzoylmethanato) chelates of Fe and Cr (Structure 5), nickel oxime chelates (Structure 6), and the nickel complex of Structure 7, nick-el(ii) 2,2 -thiobis(4-f-octylphenolato)- -butylamine. 

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