摘要
本文采用水热晶化法,从SiO_2-WO_3-(TPA)_2O-NH_4_F-H_2O体系中合成出W-ZSM-5型分子筛。X射线多晶衍射验证其物相为ZSM-5型分子筛,并测定了晶胞参数。结果证明W-ZSM-5分子筛的单位晶胞体积随杂原子W含量的增加而膨胀。红外光谱研究表明,T-O-T反对称伸缩振动吸收峰和环振动吸收峰均随产物中W含量的增加而向低波数方向移动,这与分子筛骨架中W对Si的取代相一致。X射线电子探针分析及X射线光电子能谱测定均表明杂原子W存在于分子筛骨架中。甲醇转化反应表明W-ZSM-5分子筛具有一定的催化活性。
The heteroatom type molecular sieves W-ZSM-5 were synthesized from SiO2-WO3-(TPA)2O-NH4F-H2O system by hydrothermal crystallization method. The phase and unit cell parameters were verified by X-ray diffraction analysis. The results show that the unit cell volume of W-ZSM-5 molecular sieves swells as the W content increases. IR spectra reveal that T-O-T antisymmetric stretch and ring stretch shift to lower wavenumber side with increasing the W content, this fact coincides with that the Si-O bond is substituted by longer W-O bond in the zeolite framework. Both X-ray probe micrograph analysis and XPS study demonstrate that heteroatom W is located in the framework of molecular sieves. W-ZSM-5 molecular sieves show catalytic activity to a certain extent in methanol conversion reaction.
基金
国家自然科学基金
