Studies on the Conversion of FAU Zeolites to SSZ-13: The Rate Advantage of Having Both Si and Al in the FAU Reagent

Use of FAU zeolite to form other zeolites (IZC) withthe use ofan organic structure directing agent (OSDA) has gained great traction.Here we show that the use of a reagent (CBV-720, a high silica dealuminatedFAU from Zeolyst) with both the Al and Si atoms in a lattice, andat an ideal Si/Al ratio, greatly enhances the rate of conversion toSSZ-13 (CHA structure). In the course of the studies, we exploredthe comparison of static, tumbling, and stirred reactors. We alsosaw that there was a temperature dependence where the best reactioncondition, OSDA I and CBV-720, works at 95 & DEG;C but a number ofother OSDA and reagents do not. The degradation of CBV-720 to an amorphousphase also still transforms just as rapidly as the intact structure.Because ion exchange was thought to be potentially a key nucleationfactor, seeing that the degraded (amorphous) material had lower ionexchange was just as effective reduced the importance of this step.Experiments with an inhibiting OSDA (VI) showed that conversion couldbe slowed in the best reaction systems and completely stopped in someothers. The inhibition appears to function at the nucleation stage. Crystallization of SSZ-13 is faster andcan be at a lowertemperature when a high silica form of FAU is used in the synthesis.Why?