Parametric sensitivity analysis showed that for nonreactive systems, the adsorption equilibrium assumption can be safely invoked for transient CO adsorption and desorption, and that intrapellet diffusion resistances have a strong influence on the time scale of the transients (they tend to slow down the responses). The latter observation has important implications in the analysis of transient adsorption and desorption over supported catalysts that is, the results of transient chemisorption studies should be viewed with caution, if the effects of intrapellet diffusion resistances are not properly accounted for. [Pg.99]

Let us first consider mixtures of pure CO and C02, all points of which lie on the X axis. The equilibrium in this system is fully described by Equation 3. As the temperature increases, the equilibrium constant decreases, and CO becomes stable. It is apparent (Figure 4) that, as the temperature increases, the intersections of the curves for different temperatures move close to pure CO, thus increasing the region of no graphite deposition. [Pg.47]

Numerical values of k and K, the equilibrium constant for Co(CN)5X 3 formation, have been assembled in Table IV. In the three cases where temperature coefficient data is available, it can be seen that the relative values of k4 are determined by the differences in both AH and AS. A comparison of k and K indicates that an increase in K is accompanied by a decrease in k. For any given nucleophile 4 and K may be related by the expression K = k kz/kzki. This latter expression has been used to calculate the numerical values of K for the SCN fcnd N3" systems where equilibrium data is not available. [Pg.41]

When systems are pushed together, nonbonded electrons, on the other hand, tend to retreat toward the system that has the more diffuse orbitals. In this case that is C, B, or Be. Since the nonbonded electrons are generally in orbitals less far out, this effect occurs at closer distances and, according to our calculations, wins out at equilibrium distances for CO and BF. This is the only effect for BeNe, and the moment is in the same direction at all of the distances we show. This retreat of electrons is definitely a result of the Pauli exclusion principle. [Pg.175]

The above applications show that computational chemistry has provided the answers to a number of questions. Much work still needs to be done, however. Despite the severe approximations involved in using model systems, a first step has now been taken. From the structure of intermediates and TS s determined for model systems, we have described the main features of the catalytic cycle and laid the ground for the development of more elaborate models. Topics such as ee ea equilibrium and the infrared spectra of HRh(CO)2(diphosphine) have been satisfactorily interpreted. [Pg.184]

The number of beds in series is an independent variable in the process design of such a system. It can be shown by analysis that the volume of recycle gas decreases almost in proportion to the increase in number of beds. Offsetting the reduction in recycle volume is the pressure drop across the system. Theoretical recycle power requirements then decrease somewhat as the number of beds increases. This is plotted in Figure 13 where it is assumed that (a) the make-up gas contains three moles H2 to one mole CO (b) the outlet gas composition corresponds to the equilibrium for Reactions 1, 2, and 3 (c) the recycle gas has the same composition as the outlet gas (d) inlet and outlet gas temperatures are 260° [Pg.30]

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