Bi-MSU-4介孔分子筛催化过氧化氢氧化苯乙烯  

Oxidation of styrene to benzaldehyde with H_2O_2 catalyzed by Bi-MSU-4 mesoporous molecular sieves

作　　者：官金明 陈晓晖[1] 魏可镁[1] 

机构地区：[1]化肥催化剂国家工程研究中心福州大学化学化工学院,福建福州350002

出　　处：《工业催化》2011年第8期40-45,共6页Industrial Catalysis

基　　金：国家自然科学基金资助项目(20976030);福建省高等学校新世纪优秀人才支持计划(HX2006-100)

摘　　要：采用Tween-40为模板剂,正硅酸乙酯为硅源,硝酸铋为铋源,在常温、常压条件下合成Bi-MSU-4介孔分子筛,并用于苯乙烯催化氧化反应。热力学计算表明,苯乙烯催化氧化反应为不可逆反应。在半间歇反应釜进行单因素及正交实验,结果表明,反应最佳温度(80～90)℃,过氧化氢与苯乙烯物质的量比为3.37∶1,甲醇40 mL,催化剂用量0.15 g。对反应机理进一步分析推测,骨架Bi、过氧化氢及甲醇之间由于存在氢键而形成稳定的五元环过渡态,该五元环能释放出一个质子,使反应过程产生B酸中心,具有更强的氧化性,能够更好地解释碳碳双键断裂生成醛的实验现象。Mesoporous molecular sieves Bi-MSU-4 were synthesized using Tween-40 as the template, TEOS as silicon source and Bi（ NO3 ）3 · 5H2O as bismuth source under the condition of normal tempera- ture and pressure, and was used to catalyze the oxidation of styrene to benzaldehyde. The results of thermodynamic calculation showed that the catalytic oxidation of styrene was irreversible reaction. The experimental results indicated that the optimum reaction condition was obtained as follows：reaction temperature （80 -90） ℃ ,molar ratio of H2O2（30wt% ） to styrene 3.37：1 ,the dosage of methanol and the catalyst 40 mL and 0.15 g respectively. With the formation of the five member ring intermediate among Bi active sites, H2O2 and methanol,the energy of the system decreased and the five member ring intermediate produced a Bronsted acid centre, which had stronger oxidizability and could break the double bond of styrene. That account for better activity of Bi-MSU-4 for styrene oxidation to benzaldehyde with H2O2.

关 键 词：催化化学 Bi—MSU-4介孔分子筛 苯乙烯 苯甲醛 反应机理 催化氧化 

分 类 号：TQ424.25[化学工程] TQ241.21