Conversion of faujasites to high-silica chabazite SSZ-13 in the presence of N,N,N-trimethyl-1-adamantammonium iodide

Abstract

The hydrothermal synthetic conversion of aluminium-rich zeolites to organo-zeolites in the presence of N,N,N-trimethyl-1-adamantammonium cations is now extended to the faujasite system. Rates of conversion are seen to be dramatically affected by various treatments of the FAU (faujasite) zeolites. Rates are depressed by steaming FAU zeolites, by ion-exchanging them with unreactive organic cations, or by silylating the surface of the zeolite. Surprisingly, the inhibition is removed by calcining away the organosilyl groups. For a reactive FAU zeolite (Y-62), the extent of conversion was proportional to organo-cation content, with other variables fixed; rates of conversion were also related to hydroxide ion concentration at the start of reaction.