丙烯醇催化氨化合成3-甲基吡啶催化剂的制备及性能

采用浸渍法制备了一系列H-ZSM-5分子筛负载过渡金属锌催化剂，在固定床反应器上考察了这些催化剂对丙烯醇催化氨化合成3-甲基吡啶的催化性能。通过对H-ZSM-5的硅铝比、锌负载量对催化剂催化性能影响的考察，发现硅铝比为80、锌负载量为12%时得到的催化剂Zn₁₂/H-ZSM-5（80）的催化性能最佳。在常压、反应温度420℃、氨醇摩尔比3：1、空速300 h^-1条件下，丙烯醇在该催化剂上的转化率和3-甲基吡啶的选择性分别达到97.8%和37.9%。利用X射线衍射（XRD）、X射线光电子能谱（XPS）以及吡啶吸附红外对催化剂进行了表征，结果表明，Zn₁₂/H-ZSM-5（80）上负载的Zn²⁺为L酸；在丙烯醇生成3-甲基吡啶的反应过程中催化剂的脱氢活性物种为氧化锌，而加成和环合反应则主要是由催化剂中的L酸催化实现的。

Preparation and performance of Zn/H-ZSM-5 catalyst for catalytic amination of allyl alcohol to 3-picoline

H-ZSM-5 supported zinc catalysts were prepared by impregnation method, and their catalytic performances for amination of allyl alcohol to 3-picoline were evaluated in a fixed-bed reactor. It is found that the catalyst Zn₁₂/H-ZSM-5(80) (H-ZSM-5 with 80 silicon/aluminum (Si/Al) ratio and zinc loading of 12%) shows the best performance among all the studied catalysts. 97.8% conversion of allyl alcohol and 37.9% selectivity toward 3-picoline are obtained on this catalyst using reaction conditions: atmospheric pressure, at 420℃, ammonia/allyl alcohol mole ratio 3:1 and gas hour space velocity 300 h^-1. The characterization results, obtained by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and FT-IR of absorbed pyridine, indicate that zinc on Zn₁₂/H-ZSM-5(80) is Zn²⁺, there is Lewis acid on HZSM-5. In 3-picoline formation, ZnO provides active sites of dehydrogenation reaction, and addition and cyclization reactions are mainly catalyzed by the Lewis acid.