Catalytic system, theoretical design

It has been our goal to design a catalytic system theoretically. To the end of this goal, we have so far analyzed the organometallic reactions by using the ab initio MO calculations. Recently, we have completed the theoretical study of the catalytic cycle of hydrogenation by the Wilkinson catalyst (2), of which mechanism has been proposed by Halpern (3). This catalytic cycle shown in Scheme 1 consists of oxidative addition of H, coordination of olefin, olefin insertion, isomerization, and reductive elimina-... 

The innate complexity of practical catalytic systems has lead to trial and error procedures as the common approach for the design of new and more proficient catalysts. Unfortunately, this approach is far from being efficient and does not permit to reach a deep insight into the chemical nature of the catalytic processes. The consequence of this difficulty is a rather limited knowledge about the molecular mechanisms of heterogeneous catalysis. To provide information about catalysis on a molecular scale, surface science experiments on extremely well controlled conditions have been designed and resulted in a new research field in its own. However, even under these extremely controlled conditions it is still very difficult, almost impossible, to obtain precise information about the molecular mechanisms that underlie catalytic processes without an unbiased theoretical guide. The development of new and sophisticated experimental techniques that enable resolution at... 

It is important to determine the experimental space, since the prediction ability of the presented technique is limited to the space. If some factors are not included in the space, their eflFects will not exist in the relationsMp models. For a catalytic system, essential influential factors can be selected based on the theoretical and enq)irical knowledge as well as the results of literature. Then the experimental space can be determined reasonably. In order to have the NN model in the first iteration be capable of describing the catalytic relationship approximately, the original points must be distributed evenly in the experimental space. For this purpose, the orthogonal design or other method should be used to schedule the original points. At these experimental points the catalysts are prepared and evaluated. 

From both academic and industrial perspectives, the critical deficiency of ZN catalysts remains an inability to produce fundamentally different polyolefin materials of unique structure or composition, at will, by applying a set of experimentally derived and theoretically validated first principles for the de novo design of new generations of ZN catalysts. As is often the case with heterogeneous catalysts, such advances have first required the development of homogeneous, solution-phase catalytic systems which, in the present case, are based on molecularly well-characterized... 

In this book we have provided an overview of the physical chemistry of catalytic systems with a focus on molecular mechanistic aspects. Theories, concepts and techniques to describe the relevant chemistry have advanced to a state that the reaction mechanism in heterogeneous catalysis is becoming well understood. Clearly, similar advances relevant to the practice of catalyst synthesis and design are now on the near horizon. The foundation of theoretical molecular heterogeneous catalysis provides a firm basis towards these future endeavors. 

Phase-transfer catalysis (PTC) is the most widely synthesized method for solving the problem of the mutual insolubility of nonpolar and ionic compounds. The liquid-solid-liquid phase-transfer catalysis (LSLPTC) can overcome the purification of product and the separation of reactant and catalyst in the liquid-liquid phase-transfer catalytic reaction. The main structure of LSLPTC discussed in this study was focused the quaternary ammonium poly(mcthylstyrene-resin system. The reaction mechanism, catalytic activity, characterization of catalyst, theoretical modeling, mass transfers of reactant and pnxluct. and reactor design of LSLPTC were investigated. 

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