Kinetic shift intrinsic

Figure 2. RRKM calculations of the kinetic shift for model hydrocarbon ion dissociations as a function of ion size. Calculations are shown both for a fairly weakly bonded ion (1.86 eV) and a fairly strongly bonded one (3.10 eV), and in each case both the conventional and the intrinsic kinetic shifts are plotted.

Xu, Z. and Froment, G., Methane steam reforming, methanation and water-gas shift I. Intrinsic kinetics, AIChE., 35, 88,1989. 

Jin F, Balasubramaniam R, Stebe KJ (2004) Surfactant adsorption to spherical particles the intrinsic length-scale governing the shift from diffusion to kinetic-controlled mass transfer. J Adhes 80 773-796... 

Detailed information on the intrinsic kinetic expression for this catalyst will be available elsewhere (3). The water-gas-shift reaction proceeds essentially to equilibrium (and hence completion) under our conditions, and based on the observed product composition, the stoichiometry for the reaction becomes ... 

Another contribution to variations of intrinsic activity is the different number of defects and amount of disorder in the metallic Cu phase. This disorder can manifest itself in the form of lattice strain detectable, for example, by line profile analysis of X-ray diffraction (XRD) peaks [73], 63Cu nuclear magnetic resonance lines [74], or as an increased disorder parameter (Debye-Waller factor) derived from extended X-ray absorption fine structure spectroscopy [75], Strained copper has been shown theoretically [76] and experimentally [77] to have different adsorptive properties compared to unstrained surfaces. Strain (i.e. local variation in the lattice parameter) is known to shift the center of the d-band and alter the interactions of metal surface and absorbate [78]. The origin of strain and defects in Cu/ZnO is probably related to the crystallization of kinetically trapped nonideal Cu in close interfacial contact to the oxide during catalyst activation at mild conditions. A correlation of the concentration of planar defects in the Cu particles with the catalytic activity in methanol synthesis was observed in a series of industrial Cu/Zn0/Al203 catalysts by Kasatkin et al. [57]. Planar defects like stacking faults and twin boundaries can also be observed by HRTEM and are marked with arrows in Figure 5.3.8C [58],... 

An increased kinetic isotope effect at a higher temperature is not compatible with a simple reaction but only with a mechanism in which a pre-equilibrium is shifted at higher temperatures to reacting species, whose intrinsic isotope effect is higher. The inconstancy of the kinetic order n and of the thermodynamic parameters as functions of [HA] and T, leads to analogous conclusions. The evaluation of all experimental results is compatible with mechanism (68). Formation of the diazoamino compound (N-coupling) takes place throu two intermediates, a 1 1 addition complex (HAArNj )n and the N-[Pg.50]

Xu J, Proment GF (1989). Methane Steam Reforming, methanation and Water-Gas Shift I. Intrinsic Kinetics. AIChE J 35(l) 88-96... 

The analysis of critical phenomena, such as hysteresis and self-oscillations, gives valuable information about the intrinsic mechanism of catalytic reactions [1,2], Recently we have observed a synergistic behavior and kinetic oscillations during methane oxidation in a binary catalytic bed containing oxide and metal components [3]. Whereas the oxide component (10% Nd/MgO) itself is very efficient as a catalyst for oxidative coupling of methane (OCM) to higher hydrocarbons, in the presence of an inactive low-surface area metal filament (Ni-based alloy) a sharp increase in the rate of reaction accompanied by a selectivity shift towards CO and H2 takes place and the oscillatory behavior arises. In the present work the following aspects of these phenomena have been studied ... 

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