Synthesis, characterization and structure analysis of UZM-22, a MEI-type zeolite framework structure

ZSM-18 related zeolite UZM-22, framework type MEI, was synthesized with choline as structure directing agent (SDA). Sr2+ and Li+ are additional essential components in the synthesis. Rietveld structure analysis of the as synthesized sample confirmed the proposed crystal structure in space group P63/m with a = 13.1544(7) and c = 15.7409(3) and composition (Sr1.17Li0.05)[Si27.92Al6.08O68]∗3.69SDA∗23.85H2O. Calcination showed that the material is stable up to at least 600 °C. Solid state NMR experiments revealed that the framework de-aluminated upon calcination and that Li is part of the as-made material as cation. N2 adsorption experiments confirmed the low framework density with a high surface area of 592 m2/g. The 12R pore has a diameter of 6.9 Å. Ammonium TPD revealed a high number of acid sites.