Diffusion in Zeolites . Transport phenomena often play dominant roles to determine the speed and selectivity of catalytic reactions. One of the most intriguing is shape selectivity in zeolites, containing channels with diameters comparable to those of reactant and product molecules. This rich spectrum of unexpected and exciting properties is waiting for further experimental and theoretical research.
Greater understanding can lead to technological advances.
Solid Alkylation Catalysis. Environmental considerations have ruled out traditional methods to increase octane number, including tetraethyl lead, aromatics, and olefins. The only environmentally benign species left for gasoline are iso-paraffins and oxygenates. Currently, alkylation takes place by liquid phase catalysis with HF and H2SO4, which is being phased out for environmental reasons. Solid alkylation catalysts do not have environmental problems, and are being considered for replacement.