From Charge Density Mismatch to a Simplified, More Efficient Seed-Assisted Synthesis of UZM-4

摘要

The charge density mismatch (CDM) approach has been a strategy to apply multiple templates in the zeolite synthesis. In the synthesis of the UZM-4 zeolite, tetraethy-lammonium (TEA) aluminosilicate solution is used as CDM solution although the TEA cation is not incorporated in the final product. We focused on the aging process to prepare the CDM solution, and a more simplified pathway for the synthesis of UZM-4 is explored. The preparation of homogeneous aluminosilicate solution prior to the addition of crystallization-inducing templates, tetramethylammonium, and lithium cations in this work, is essential to the successful synthesis of UZM-4 crystals. We confirmed that small aluminosilicate species were formed under the preparation of CDM solution and stabilized in the liquid phase. On the basis of these results, the efficient, economical synthesis of the UZM-4 zeolite, eliminating the TEA aluminosilicate solution, was achieved for the first time by a seed-assisted approach.