Direct synthesis of the aluminosilicate form of the small pore CDO zeolite with novel OSDAs and the expanded polymorphs

Abstract

A general procedure to synthesize the Al-containing layered CDO precursor (PreCDO) is presented, allowing its preparation under broad Si/Al molar ratios by using novel pyrrole-derived organic molecules as organic structure directing agents (OSDAs). The direct calcination of the PreCDO materials results in crystalline Al-containing small-pore CDO zeolites with controlled Al species in tetrahedral coordination. In contrast, mild acid treatments on the PreCDO materials allow achieving medium-pore interlayer expanded CDO zeolites (IEZ-CDO). These expanded zeolites show high crystallinity, high porosity and controlled Si/Al molar ratios. Finally, preliminary catalytic results indicate that the Al-containing CDO and IEZ-CDO samples show good activity and selectivity for the selective catalytic reduction (SCR) of NOx, and methanol-to-olefins (MTO) processes, respectively.