Synthesis of high silica *BEA type ferrisilicate (Fe-Beta) by dry gel conversion method using dealuminated zeolites and its catalytic performance on acetone to olefins (ATO) reaction

Abstract Zeolite Beta has been widely utilized on large molecular systems because of its three dimensional large micropores, 12-membered ring. Controlling amount of acid and its strength of zeolites depending on the composition is very crucial to improve their catalytic performance. Incorporation of heteroatoms into the framework of zeolites is one of the effective ways to control catalytic activities. However, it is difficult to synthesize high-silica zeolite Beta with heteroatoms, which has been limiting the functions of zeolite Beta. To overcome the problem, we developed a dry gel conversion method using dealuminated zeolites; we can synthesize *BEA type ferrisilicate (Fe-Beta). In this method, it is necessary to use two silica sources; dealminated Beta and colloidal silica. The dissolving process of these silica sources by NaOH plays a significant role in the crystallization to Fe-Beta. The Fe-Beta shows higher selectivity to isobutene on acetone-to-olefins (ATO) reaction compared to Al-Beta and Fe-MFI. This is due to the acid strength weakened by substituting Al by Fe and the large diffusivity of isobutene in the large micropores of *BEA structure.