SYNTHESIS OF ZEOLITE AND ZEOTYPES ISOMORPHOUS WITH ZEOLITE BETA

摘要

The present invention provides a process for the preparation of a crystalline material which comprises the steps of (i) forming a reaction mixture comprising water (H2O), a source of silicon dioxide (SiO2), a source of fluoride ions (F-), a source of tetraethylammonium cations (TEA+) and, optionally, a source of an oxide of a trivalent element (X¿2?O3), the reaction mixture having a composition expressed in terms of mole ratios in the following ranges: H2O/SiO2, of from 4 to 50; SiO2/X2O3, of at least 10; TEA?+/SiO¿2, of from 0.125 to 0.80; F-/SiO2, of from 0.1 to 2; (ii) crystallising the reaction mixture; and (iii) recovering the crystalline material formed, wherein the pH after completion of crystallization is in the range from 6 to 12, preferably from 8 to 9.5.