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The rate constants were determined at four different temperatures (35.0–50.0 °C) as indicated earlier, the values of different thermodynamic parameters such as activation energy ( ∆E ), entropy of activation ( ∆S # ), Arrhenius frequency factor ( A

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-Zn/ZSM-5 and Fe-Zn/ZSM-5 after H 2 pretreatment. The activation energies are higher after H 2 pretreatment than after He pretreatment and the tendency of the E a for Me-Zn/ZSM-5 follows the activity of the samples. The results are presented in Table 1

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multiplied by 4 conditions). In order to select appropriate kinetic parameters for the estimation of activation energies, some of kinetic parameters provided in Table 1 were selected in a combinatorial manner and considered temperature dependent. In such a

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: Here, n = 2 for the LHHW model, n = 1 for the ER model and n = 0 for the PH model. k f is the Arrhenius pre-exponential factor for the forward reaction, K eq is the equilibrium constant of the reaction, E 0 is the activation energy of the

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found to follow the Arrhenius equation ( Fig. 9 ). Pre-exponential factors, activation energies and enthalpies for adsorption to desorption ratio ( ) in comparison to previous findings are reported in Table 4 . Table 4

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where With these expressions, the rate of SCR of NO is given by In reality, the adsorption and activation energies are expected to depend strongly on the state of the site, the rate

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. Hydrodesulfurization activity The activity was measured at three temperatures and the activation energy E was calculated. It varied not only in set A (29–91 kJ/mol) but surprisingly also in set B (35–54 kJ/mol). We have not found any correlation of

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mentioned above, the catalytic cycle of the hydrosilylation reaction is composed of two transition states. The first one corresponds to the insertion of the ketone into the Rh–Si bond, which is the rate-determining step with relatively high activation energy

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the divided value between products yield and oxygenate conversion, namely product selectivity. The parallel mechanism [ 5 ] also indicated the selectivity is affected by the activation energy for each product, but has little relationship with the feed

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–O bond and increases the basicity of the catalyst surface. Besides, the addition of cerium decreases the activation energy for styrene formation and the catalyst activity is increased by higher concentrations of cerium oxide [ 3 , 5 , 6 ]. Despite the

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