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以正十二胺(DDA)为模板剂、正硅酸四乙酯(TEOS)为硅源、硝酸铈铵((NH_4)_2Ce(NO_3)_6)为金属活性组分,采用原位合成法,在45℃下,制备不同含量的金属铈改性的HMS介孔材料(Ce-HMS),对其结构进行X射线衍射(XRD)、傅里叶变换红外光谱(FT-IR)、扫描电镜(SEM)、N_2吸附-脱附(BET)等一系列表征。以Ce-HMS为催化剂,30%H_2O_2为氧源,冰乙酸为溶剂,催化乙苯氧化合成苯乙酮,探讨了催化剂用量、30%H_2O_2用量、反应时间、反应温度和溶剂种类及用量对乙苯的转化率、苯乙酮的产率及选择性的影响,考查了催化剂的重复使用性。实验结果表明,乙苯催化氧化主要生成苯乙酮,同时产生少量的苯甲酸等副产物。当硝酸铈铵与正硅酸四乙酯摩尔比为0.04,催化剂质量0.1 g,反应温度为100℃,反应6 h,双氧水3 mL,溶剂乙酸为4 mL时,乙苯的转化率达88.8%,苯乙酮产率达到84.6%,选择性为95.3%。催化剂重复使用效果良好。
Using DDA as templating agent, tetraethyl orthosilicate (TEOS) as silicon source and ceric ammonium nitrate ((NH 4) 2 Ce (NO 3) 6) as the metal active component, The Ce-HMS mesoporous materials (Ce-HMS) with different content of cerium were prepared at 45 ℃, and their structures were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) SEM), N 2 adsorption-desorption (BET) and a series of characterization. Using Ce-HMS as catalyst, 30% H 2 O 2 as oxygen source and glacial acetic acid as solvent, the synthesis of acetophenone by catalytic oxidation of ethylbenzene was discussed. The effects of catalyst amount, amount of 30% H 2 O 2, reaction time, reaction temperature, The conversion of benzene, the yield and selectivity of acetophenone, the reusability of the catalyst was examined. The experimental results show that ethylbenzene mainly produces acetophenone by catalytic oxidation and produces a small amount of by-products such as benzoic acid. When the molar ratio of ceric ammonium nitrate and tetraethyl orthosilicate is 0.04, the mass of catalyst is 0.1 g, the reaction temperature is 100 ℃, the reaction time is 6 h, the amount of hydrogen peroxide solution is 3 mL and the solvent acetic acid is 4 mL, the conversion of ethylbenzene reaches 88.8% , Acetophenone yield of 84.6%, selectivity of 95.3%. Reuse of catalyst works well.