ABSTRACT
The petroleum processing catalysts that have aroused the greatest interest and that constituted a major advancement when they were first introduced in the 1960s are the molecular sieves or zeolites. It was once thought that the research in zeolites had reached a mature state, but the synthesis of a continuous series of high silica/alumina materials has greatly expanded the potential of these materials. In 1756, Cronstedt coined the term zeolite to describe a class of naturally occurring minerals composed of silica and alumina. In 1949, Robert Milton, of Union Carbide, discovered methods to produce synthetic zeolites by a low-temperature hydrothermal process. Application of synthetic zeolites in heterogeneous catalysis has had a major impact in both the petroleum and chemical industries. A mixture is prepared by adding a solution of 1.4 g of NaOH in 10 mL of water to 44 g of aqueous colloidal silica (30 wt % SiO2, Ludox) with stirring.
