Design for sieving

ZEOLITES and zeolite-like molecular sieves are fascinating materials from both an intellectual and a practical standpoint. Their elegant crystal structures have voids with precise and uniform sizes, in the range of about 0.4-1.5 nn, which can be used for molecular sieving (that is, to discriminate between molecules of similar size). Zeolites are used as shape-selective catalysis they can encourage reactions that favour one particular product over another even when the difference in size between the two species is as little as 0.03 nm, as is the case for p-xylene and o-xylene. Further, zeolites are environmentally benign solids. So their use as catalysts continues to burgeon