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Synthesis of MgO and MgO–CeO 2 by co-precipitation for the catalytic conversion of acetone by aldol condensation
Reaction Kinetics, Mechanisms and Catalysis ( IF 1.8 ) Pub Date : 2020-09-10 , DOI: 10.1007/s11144-020-01868-8
Ma. Elena Manríquez-Ramírez , Ignacio Elizalde , Emma Ortiz-Islas

This study deals with the synthesis of catalytic samples containing MgO and 10, 15 and 25 wt% of CeO2 by co-precipitation method for aldol condensation of acetone. The obtained powders were characterized by X-ray diffraction (XRD), Raman spectroscopy, temperature programmed desorption of CO2, X-ray photoelectron spectroscopy, nitrogen physisorption, and atomic force microscopy. The materials exhibited XRD patterns corresponding with cubic MgO and fluorite phase of ceria, medium and weak strength basic sites, characteristic electronic properties and distinctive trends regarding textural properties. The aldol condensation of acetone was carried out using the prepared catalyst samples; a decrease in acetone conversion as function of time-on-stream was noted for all catalyst, being the best performance exhibited by the sample containing 10 wt% ceria. The selectivity toward the different products of aldol condensation of acetone was dependent on catalytic sample, which was related to the unique properties of those solids. Diacetone alcohol was best produced by MgO-25 wt% ceria; for mesityl oxide yield, an increase in selectivity as time-on-stream was observed being the best material the sample MgO-10wt% ceria; whereas for phorone, the profiles indicate almost yield reduction as time-on-stream function, indicating the best performance the sample containing 15 wt% of CeO2. Isophorone was optimally produced by using pure MgO which was attributed to the presence of medium strength basic sites and adequate textural properties.



中文翻译:

共沉淀法合成MgO和MgO-CeO 2,通过醛醇缩合催化丙酮的催化转化

本研究涉及通过共沉淀法合成丙酮,羟醛缩合反应制备的含MgO和10、15和25 wt%的CeO 2的催化样品。通过X射线衍射(XRD),拉曼光谱,程序升温脱附的CO 2表征所获得的粉末。,X射线光电子能谱,氮物理吸附和原子力显微镜。该材料表现出的XRD图谱与二氧化铈的立方MgO和萤石相,中等强度和弱强度的基本位点,典型的电子性能以及有关结构性能的明显趋势相对应。使用制得的催化剂样品进行丙酮的醛醇缩合反应。对于所有催化剂,丙酮转化率随时间的流逝而降低,这是含有10wt%二氧化铈的样品表现出的最佳性能。丙酮与醛醇缩合的不同产物的选择性取决于催化样品,这与这些固体的独特性质有关。MgO-25 wt%的二氧化铈最好生产双丙酮醇。对于异丁烯氧化物产量 由于观察到运行时间是样品MgO-10wt%的二氧化铈的最佳材料,因此选择性增加。而对于佛尔酮,该曲线表明随着时间流逝函数几乎降低了收率,表明含有15 wt%CeO的样品具​​有最佳性能2。通过使用纯MgO可以最佳地生产异佛尔酮,这归因于存在中等强度的碱性位点和足够的质地。

更新日期:2020-09-11
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