Synthesis and Characterization of Silicoaluminophosphate CIT-16P and Its Transformation to SAPO-17

A silicoaluminophosphate molecular sieve, CIT-16P, is synthesized using butane-1,4-bis(quinuclidinium) [(C 7 H 13 N)-(CH 2 ) 4 -(NC 7 H 13 )] 2+ dihydroxide (DiQ-C 4 -(OH) 2 ) as an organic structure-directing agent (OSDA). Upon the removal of the OSDA, either by thermal treatment in air at temperatures exceeding 490 °C or by extended ozone treatment at 150 °C, CIT-16P transforms to SAPO-17 (ERI topology). The structure solution of CIT-16P in its as-synthesized form is obtained using a Rietveld refinement of the powder X-ray diffraction pattern. The primary composite building units (CBUs) of CIT-16P are highly distorted cancrinite ( can ) CBUs that transform into stable can units of the ERI-type framework as a result of the OSDA removal. The distortion of can CBU is maintained without transformation by the presence of tightly bound DiQ-C 4 dications in the as-synthesized form of CIT-16P.…