The effect of the synthesis procedure and variables on the resulting chemical and structural properties of molecular sieves of the MWW family was investigated in detail. In addition, dealumination procedure was optimized to decrease the concentration of framework aluminum, which might lead to the connectivity of both originally independent channel systems. MCM-22 was successfully synthesized with Si/Al ratios higher than 12, while at lower ratios MCM-56 was obtained. The molar ratio of organic templates to inorganic cations forwarded the synthesis towards MCM-22 or MCM-49. Much higher stability of MCM-22 was found against steam treatment compared to alkali treatment.
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