日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

The catalytic properties of aluminosilicate zeolites depend on many factors such as the pore structure, acid strength, and acid amounts. Among them, the acidic properties originate from the presence of protons balancing the negative charge induced by the framework Al atoms in tetrahedral sites (T sites). Recently, the distribution of Al atoms in the zeolite framework has been recognized as an important factor for activity and selectivity. Here, we have focused on the control of the distribution of Al atoms in the CHA-type aluminosilicate zeolite, which has been widely used as a solid acid catalyst in petrochemical catalytic processes and also in the methanol conversion process. We have found that the Al distribution is affected by the raw materials, especially Al and silica sources, for preparation of CHA-type aluminosilicate zeolite; the Al distribution was tuned by changing the ratio of aluminum hydroxide and FAU-type zeolite. We have successfully demonstrated that the Al distribution affected the hydrothermal stability of the zeolite and also catalytic performance.