SEARCHING FOR NEW HIGH-SILICA ZEOLITES THROUGH A SYNERGY OF ORGANIC TEMPLATES AND NOVEL INORGANIC CONDITIONS

The synergy of template molecule size and hydrophobicity and the sourc es of inorganic reagents affecting zeolite nucleation are described, i n particular, the discovery of high silica zeolites SSZ-26, 41, 42 and UTD-1 is considered in this light. Of particular value is the use of zeolites themselves as reactants; three different examples are given. Some general rules for lattice substitution and zeolite product type a re given. An unexpected use of the template used in the discovery of z eolite SSZ-42 is described now that the structure of the zeolite has b een resolved, largely from single crystal data. Finally some new synth etic conditions with considerable economic advantage are described for zeolite SSZ-25. Some new questions about the effect of organic cation s on solution instability are raised. (C) 1998 Elsevier Science B.V. A ll rights reserved.