Deactivation factors

The influence on the rate of the diverse alkylamino groups relative to NH2 appears to vary over a rather narrow range and involves deactivating factors of 1.4 or less. It is noteworthy that both V-morpho-lino and phenylamino groups are activating and involve maximum factors of 3.1 and 12, respectively. 

AAr Average Selectivity AAr Deactivation Factor OAir Average Selectivity Air Deactivation Factor... 

Figure 3 Relationship between average selectivity, deactivation factor and number of regeneration (TS-1).

The activity in aliphatic alkylation of all the alkaline and ammonium salts of H4SiWi204o and H3PW12O40 are compared in Table 4. A deactivation factor, R %, measuring the decrease of the catalyst activity after 65 min is also reported... 

Ley showed that these relationships need not be measured for every potential combination of donors, but rather the multiphcati ve relationship between these donors held with only small discrepancies. Throughout his work, Ley reports deactivation factors, which describe the decreased reactivity of a donor in comparison with the... 

The substitutent activation (or deactivation factors Ar[79JCS(P2)381] for 8.8 and 8.9 are 30 and 20, respectively. The observed partial rate factors then follow since a larger value of Af predicts a larger substituent effect. 

Another deactivation factor is the deposited substances that hinder intraparticle diffusion of reactants. The vanadium deposition is supposed to have a significant effect on the effective diffusivity in the catalyst pores. The decline of the effective diffusivity is expressed by the following equations for sulfur Ds and vanadium Dy, respectively ... 

Equation 12.2 reflects a base case of 9 mg/mile with a 0.29 m2 surface area, ratio of airflow to vehicle speed at 40%, and conversion of base case to 80% from the UAM. The deactivation factor (DF) is DF = (aged ozone conversion/ fresh ozone conversion). To determine the deactivation factor, on-road aging of radiators coated with catalyst was run for 150,000 miles and DFs at that point were determined. Freshly coated radiators were exposed to an accelerated aging test and DFs were calculated and compared for accuracy. Figure 12.4 shows the calculation of deactivation factors for two different radiators with different core geometries. 

In eqn. 2, e a(T)t j a factor that expresses the extent of catalyst deactivation with time, and may be regarded as a time constant for catalyst activity loss. This form of catalyst deactivation factor derives from the assumption that catalyst activity decays exponentially with time, at constant temperature. A and E are, respectively, the preexponential factor and the activation energy for the rate constant. E can be determined from an Arrhenius plot for k1 under conditions where the quantity e a(T)t is essentially constant. Fig. 4 shows the results of experiments that were conducted at the end of the catalyst life tests at 498°K and 538eK shown in Fig. 3. The greater extent of deactivation at 538°K is clearly evident in Fig. 4, since the data at 538°K fall well below those at 498°K. The activation energies derived from the slopes of the two lines on Fig. 4 average t7.9 kcal/mole and agree to within 0.8 kcal/mole. 

The composition/purity of the product gas from gasification is critical for the bio-SNG synthesis for example, soot formation has been found to be the catalyst deactivation factor at ECN [7], while deactivation was due to sulfur deposition on the catalyst surface for the lOkW, , pilot-scale tests COSYMA in Gussing [25]. 

Table 1 Deactivation factors for Bz-protecting groups at each position of galactosyl donor 13 ORr...

Raw predictions can be made on the impacts of the concomitant presence of several co-pollutants in the gas stream, along with target pollutants of different natures and catalyst deactivation factors on industrial applications. However, the difficulty of obtaining a real, clear picture of the interconnected effects of these parameters should encourage researchers to perform experiments in conditions increasingly closer to the target application. 

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