介孔分子筛MCM-41固载多氮杂环席夫碱与偏钒酸钠共催化氧化苯一步制备苯酚

One-step Oxidation of Benzene to Phenol Catalyzed by Sodium Metavanadate-Multinitrogen Heterocyclic Schiff Base Complex Immobilized on Mesoporous Molecular Sieve MCM-41

2-苯基-1,2,3-三唑醛和喹喔啉醛通过亚胺键固载到介孔分子筛MCM-41上,得到6种MCM-41固载多氮杂环席夫碱（L1~L6）,用FT-IR、XRD和SEM等技术手段对所制得的固载席夫碱进行表征。研究了以MCM-41固载多氮杂环席夫碱和金属盐偏钒酸钠为共同催化剂,过氧化氢为氧源,直接催化氧化苯合成苯酚,用气相色谱快速检测苯酚产率。系统地考察了配体、金属盐、温度、溶剂、催化剂用量、反应时间、氧化剂等因素对反应的影响,产率最佳可达23.9%,选择性大于90%。对催化剂扩大5倍量进行试验,得到23%的产率和93%的选择性,并且催化剂重复使用3次仍能达到19%的产率和90%以上的选择性。

2-Phenyl-1,2,3-triazoledehyde and quinoxalin-2-carboxaldehyde immobilized on mesoporous MCM-41 by imine bond respectively. Six multinitrogen heterocyclic Schiff bases（ L1 ~ L6） modified MCM-41 were synthesized. These catalysts were characterized by Fourier transform infrared spectroscopy（ FT-IR）,X-ray diffraction（ XRD）,thermogravimetric analysis（ TG） and scanning electron microscopy（ SEM）. Na VO3 and Schiff Base complex immobilized on MCM-41 was used for catalytic oxidation of benzene to phenol. The yield of phenol was determined by gas chromatography. Reaction conditions,such as ligand,metal salt,temperature,solvent,the catalyst amount,reaction time and oxidants were systematically investigated. Under optimized conditions,the yield of phenol is up to 23. 9%（ more than 90% selectivity）. Scaled-up（ 5 times）reaction test using the current catalyst system gives a good yield（ 23%） and selectivity（ up to 90%）,while catalyst shows no significant decrease of catalytic activity after 3 times recycles.