Synthetic zeolites and other microporous oxide molecular sieves

Use of synthetic zeolites and other microporous oxides since 1950 has impro ved insulated windows, automobile air-conditioning, refrigerators, air brak es on trucks, laundry detergents, etc. Their large internal pore volumes, m olecular-size pores, regularity of crystal structures, and the diverse fram ework chemical compositions allow "tailoring" of structure and properties, Thus, highly active and selective catalysts as well as adsorbents and ion e xchangers with high capacities and selectivities were developed, In the pet roleum refining and petrochemical industries, zeolites have made possible c heaper and lead-free gasoline, higher performance and lower-cost synthetic fibers and plastics, and many improvements in process efficiency and qualit y and in performance. Zeolites also help protect the environment by improvi ng energy efficiency, reducing automobile exhaust and other emissions, clea ning up hazardous wastes (including the Three Mile Island nuclear power pla nt and other radioactive wastes), and, as specially tailored desiccants, fa cilitating the substitution of new refrigerants for the ozone-depleting chl orofluorocarbons banned by the Montreal Protocol.