(90a) Synthesis of Aluminoborosilicate Isomorphous to Zeolite Tun and Its Acidic and Catalytic Properties

The TUN-type aluminoborosilicate zeolite (denoted as [Al, B]-TUN), which consist of a three-dimensional pore system with 10-ring, has been hydrothermally synthesized for the first time. The mother gel composition including aluminum, boron, organic structure-directing agent and sodium were intensively studied and optimized. The incorporation of boron as well as aluminum into the TUN framework and the resultant acidic properties were investigated by ICP-AES, structural refinement by X-ray diffraction, MAS NMR, NH₃-TPD and pyridine-adsorbed FT-IR. Furthermore, we first found that , and it exhibited a better catalytic performance in the n-hexane cracking reaction in terms of propylene selectivity than the MFI and ^*BEA-type aluminosilicate zeolites. The advanced performance could be due to the unique pore structure and suitable acid properties of [Al, B]-TUN. These features were clarified by constrain index (CI) value.