Organic catalysis over zeolites: A perspective on reaction paths within micropores

Shape-selective catalysis in zeolites

Inorganic molecular sieves: Preparation, modification and industrial application in catalytic processes

In this review, a brief survey is offered on the main nanotechnology synthetic approaches available to heterogeneous catalysis, and a few examples are provided of their usefulness for such applications. We start by discussing the use of colloidal, reverse micelle, and dendrimer chemistry in the production of active metal and metal oxide nanoparticles with well-defined sizes, shapes, and compositions, as a way to control the surface atomic ensembles available for selective catalysis. Next we introduce the use of sol–gel and atomic layer deposition chemistry for the production and modification of high-surface-area supports and active phases. Reference is then made to the more complex active sites that can be created or carved on such supports by using organic structure-directing agents. We follow with an examination of the ability to achieve multiple functionality in catalysis via the design of dumbbells, core@shell, and other complex nanostructures. Finally, we consider the mixed molecular-nanostructure approach that can be used to develop more demanding catalytic sites, by derivatizing the surface of solids or tethering or immobilizing homogeneous catalysts or other chemical functionalities. We conclude with a personal and critical perspective on the importance of fully exploiting the synergies between nanotechnology and surface science to optimize the search for new catalysts and catalytic processes.

Nanostructured materials for applications in heterogeneous catalysis

A study was made of the selectivity of zeolite catalysts due to the shape and size of their pores. Typically, their pore diameters are less than 10 angstroms, and they have pores with one or more discreet sizes. The shape and size of zeolite pores can control reactions by limiting travel of reactants or products that are larger than the pores, or by the limiting size of the cavities being smaller than a transition state of a reaction. Also included were descriptions of control and applications of shape selectivity of porous zeolite catalysts. Seven illustrations and 53 references were included.

B. Weinstein

Papers

Selective alkylation of toluene with methanol to produce para-xylene