摘要
沉淀-浸渍法制备了固体超强酸SO_4^(2-)/TiO_2催化剂,利用该催化剂合成了甲基丙烯酸甲氧基乙酯。考察了浸渍酸Hp_2SO_4浓度和焙烧温度对催化剂活性的影响,X射线衍射(XRD)分析确定催化剂为锐钛矿晶型结构。采用电子自旋共振(ESR)对催化剂进行了分析与表征,ESR波谱能够检测出催化剂空位或缺陷数量即催化剂活性的强弱,结合相关催化反应的转化率,最终确定了浸渍酸的较佳浓度为0.75 mol/L,最佳焙烧温度为450℃。研究了催化剂的重复使用性能,发现催化剂循环使用2次后活性下降明显,ESR初步分析表明其主要原因是由于催化剂表面积碳和吸附了有机物而导致的。
The solid super-acid catalyst SO4^2-/TiO2 was prepared by precipitation-impregnation method, to catalyze synthesis of 2-methoxyethyl methaerylate （MAA） from methacrylic acid and glycol. Effects of calcination temperature and H2SO4 concentration on the catalyst activity were also investigated. The anatase structure of solid super-acid catalyst was confirmed by X ray diffraction （XRD）. Electron spin resonance （ESR） technology was used to characterize the catalyst performance. The catalytic activity could be reflected from the ESR signal intensity and the spectrum shape, combining with the results of reaction conversion of MAA. The optimal H2SO4 concentration and calcination temperature were 0.75 mol/L and 450 ℃, respectively. The reusability of the catalyst was also discussed, the catalytic activity was obviously lost after being used for 2 times, which might be due to the active sites covering by carbon and organic substances based on analysis of ESR results.
出处
《化学反应工程与工艺》
CAS
CSCD
北大核心
2010年第1期19-23,共5页
Chemical Reaction Engineering and Technology
基金
国家自然科学基金(20771097)
