Micro/mesoporous aluminosilicate composites from zeolite MCM-22 precursor

Micro/mesoporous aluminosilicate composites were prepared applying a two-step hydrothermal synthesis procedure. In the first step a zeolitic component, i.e., the precursor of zeolite MCM-22 was synthesized and its swollen and partially delaminated derivatives were prepared. In the second step mesoporous MCM-41 silicate was synthesized in a slurry of the above MCM-22 type precursor from additional silicate source and using hexadecyltrimethylammonium bromide (CTMABr) template. The structure, morphology and the acidic properties of the obtained composite materials were characterized by X-ray diffraction, infrared spectroscopy, N2 adsorption isotherms, and electron microscopy (SEM and TEM). The results suggest that the composite materials were built from nanosize, randomly orientated stacks of thin layers of MCM-22 type zeolite and of mesoporous silicate MCM-41 material. The catalytic activity of the composite material was compared to that of the zeolite MCM-22 in the hydroconversion of heptane.