Pb-ZSM-5分子筛的表征及其催化活性的研究

Characterization and Catalytic Activity of Pb-ZSM-5 Zeolite

Pb ZSM 5分子筛催化剂是一种具有较强催化活性的醛氨缩合催化剂 ,其主要特点是反应条件温和、择形选择性高、副产物较少等优点。醛氨缩合反应是制备烷基吡啶最具代表性的反应路线之一。用BET、SEM、XRD和IR等技术考察了Pb ZSM 5分子筛的物理化学特性 ,并将Pb ZSM 5分子筛用于醛氨缩合反应。研究表明 ,含Pb浸渍液浓度范围在 2 %～3% (m )内可起到很好的改性作用 ,其中在 2 2 5 %～ 2 75 % (m )范围内烷基吡啶的选择性最佳。通过浸渍法使得Pb2 + 进入了ZSM 5分子筛骨架中 ,对醛氨缩合反应有较高的催化活性和选择性。采用Pb ZSM 5分子筛 ,烷基吡啶的产率可以达 75

Pb ZSM 5 zeolite has high catalytic activity in aldehyde ammonia condensation reaction. Pb ZSM 5 zeolite catalyst has the features of temperate reaction condition, high shape selectivity, and little byproduct.The aldehyde ammonia condensation reaction is one of the typical routes to manufacture alkylpyridine. The state of Pb on ZSM 5 zeolite was studied by BET,SEM,XRD and, IR methods. The Pb ZSM 5 zeolite had been used synthesizing alkylpyridine from aldehydes and ammonia. The results showed that the Pb metal content of Pb ZSM 5 zedite catalysts is about 2% to 3%, and preferably about 2.25% to 2.75% by weight of the catalyst. The results also showed that dipping method could make Pb enter the frame work of the ZSM 5 zedite. The Pb ZSM 5 zeolite showes relatively high activity and shape selectivity in the conversion of aldehydes to alkylpyridine. Using Pb ZSM 5 zeolite, the yields of alkylpyridine are more than 75.