摘要
运用度角旋转（MAS）和交叉极化（CP）等核磁共振波谱和红外光谱技术，分别对采用不同模板剂制备的高硅ZSM－5分子筛和以此为母体，经气固同晶取代法得到Ti－ZSM－5分子筛的结构特性进行了研究．结果表明：在水热法合成高硅ZSM-5分子筛过程中，模板剂明显制约着所制得的分子筛的结构特性．通过选用合适的模板剂，可直接获得具有正交晶系结构的高硅ZSM－5分子筛．在随后的气固相同晶取代过程中，钛原子通过占据分子筛骨架中的缺陷位进入骨架，形成具有一定Ti／Si比例的钛硅分子筛（Ti－ZSM－5）。骨架结构中缺陷位的含量直接影响分子筛的载钛量。
Solid state NMR with magic angle spmning (MAS) and cross polarization(CP) tech-niques, and IR spectroscopy have been used to investigate the structural Characterizations of thehighly siliceous ZSM-5(S-1) zeolites synthesized using various organic ammoniums or ammes astemplates and the Ti-ZSM-5 zeolites prepared by the solid reaction of ZSM-5 zeolites with titaniumtetrachloride vapor at 873K . It has been shown that the strneture of the ZSM-5 zeolite isstrongly governed by the variety of the templates used in the synthesis, and the zeolites templatedby TEABr and HDA present the orthorhombic symmetry, while those prepared using TPABr andTPAOH as templates exhibit only monoclmic symmetry . Furthermore, thedistribution of thestructural defects in the obtained zeolites was found to be also dependent on the templates used.These T-atom defect sites in the framework, defined as Si(OSi)3O-,are available for the insertionof Ti atoms in the subsequent reaction with titaniuintetrachloride vapor at elevated temperaturesand the concentration of defects was proved to be correlative to the amounts of Ti atoms beingderived into the framework of zeolite.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
1998年第4期320-326,共7页
Acta Physico-Chimica Sinica
