CATALYSIS UNDER TRANSIENT CONDITIONS Catalyst

Jain, A.K., Hudgins, R.R. and Silveston, P.L., "Adsorption/ Desorption Models How Useful to Predict Catalyst Behavior under Transient Conditions", paper submitted to Seventh North American Meeting, The Catalysis Society, Boston, 1981. 

An effective approach to help address the issues involved in controlling catalyst performance is to formulate and analyze reaction schemes that describe the essential chemistry taking place on the catalyst surface. This approach has been used successfully in catalysis research for many years. We suggest that this approach will see increased use in catalysis research. Specifically, continuing improvements in computer capabilities allow rapid analysis of complex reaction schemes for all common reactor configurations (e.g., reactors operating at steady state as well as under transient reaction conditions and nonisothermal reactors). Moreover, recent advances in quantum... 

Figure 8.31. Comparison between experimental and calculated according to eq. 8.117 data for three-phase catalytic hydrogenation in a fixed bed reactor (E. Toukoniitty, P. MSki-Arvela, A. Kalantar Neyestanaki, T. Salmi, D. Yu. Murzin, Continuous hydrogenation of l-phenyl-1,2 - propanedione under transient and steady-state conditions, regioselectivity, enantioselectivity and catalyst deactivation, Applied Catalysis A General, 235 (2002) 125).

With the inclusion of more sophisticated techniques such as those mentioned above and others, NMR is an excellent quantitative tool for structural catalyst characterization. On the other hand, the question of how this information can be used to understand catalytic mechanisms and to design more potent catalysts often remains unresolved by these studies. Perhaps this is so because to date most NMR applications have sought to correlate catalytic activities with specific structural features present either in the catalyst or on its surface under room temperature conditions. In future studies there should be increasing emphasis on catalyst characterization under operation conditions in situ, including the search for transient adsorbates and reactive intermediates. In fact, such studies are now emerging in other fields of catalysis [90-92]. 

Burch, R. Loader, P. K. Investigation of methane oxidation on Pt/Al203 catalysts under transient reaction conditions. Applied Catalysis A General 122, 169-190 (1995). 

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