双组元Y／MCM-41中微孔复合分子筛的合成和表征

通过原位处理分步晶化、水热合成的方法，首次从NaY凝胶出发制备了含有Y和 MCM-41两种分子筛成分的Y/MCM-41中微孔复合分子筛新材料，考察了合成条件对复 合分子筛晶化的影响。利用层厚法和相对结晶度工作曲线法确定了复合材料中两种 分子筛的相对含量。通过XRD，MAS NMR，SEM，XPS，IR，N_2吸附脱附、热处理等 手段对复合材料进行了表征，并与MCM-41和Y型分子筛的有关性能进行了对比研究 。结果表明，复合分子筛材料的热和水热稳定性高于相同分子筛比例的机械混合样 品。与机械混合物样品相比，其中孔表现出孔径缩小、也道规整性变差、孔壁增厚 和部发结晶化的特点，复合材料中两种分子筛之间存在界面效应，推测Y/MCM-41复 合分子筛材具有“包覆式”结构特征。以模型化合物理学，3，5-三异丙基为进料 考察了其催化裂化活性，中微孔复合分子筛的催化裂化活性优于机械混合样品。

Synthesis and Characterization of Y/MCM-41 Composite Molecular Sieve

A novel binary molecular sieve composite, namely Y/MCM 41, was synthesized from NaY gel by an in situ two step hydrothermal crystallization process, and the crystallization parameters were optimized. V a t curve and relative crystallinity methods were employed to determine the amounts of the constituent parts of Y and MCM 41 in the composite. The product was characterized by XRD, MAS NMR, SEM, XPS, IR, N 2 adsorption/desorption and thermal treatment methods. It indicated that Y/MCM 41 was different from the mechanical mixture of MCM 41 and Y. The composite has a narrow, relatively disordered pore structure, a thicker and partially crystalline wall, and a higher stability. And it showed that the Y zeolite was enwrapped by the MCM 41. 1,3,5 triisopropylbenzene was employed as a model compound to detect the cracking activity of the composite molecular sieve, and a higher conversion was observed by using Y/MCM 41 catalyst than that of the mechanical mixture catalyst.