Shape-selective catalysis is important for synthesis of organic chemicals and for processing of petroleum fractions and fuels.
The catalytic reaction that depends upon the structure of pores of the catalyst and the size of the reactant and product molecules is called shape/selective catalysis.
Zeolites are good shape/selective catalysts because of their honeycomb-like structures. Zeolites are aluminosilicates i.e., three dimensional network silicates in which some silicon atoms are replaced by aluminium atoms.