收稿日期: 2016-02-02
网络出版日期: 2016-11-15
基金资助
国家自然科学基金（21406244，21276267）资助
Effects of crystallization time on the catalysis of Cs-La/SBA-15 for aldol condensation of methyl propionate and formaldehyde
Received date: 2016-02-02
Online published: 2016-11-15
丙酸甲酯（MP）和甲醛（FA）缩合反应制备甲基丙烯酸甲酯（MMA）是一条绿色可持续的生产MMA的工艺路线，该路线的关键是开发高效的催化剂，而载体的性质直接影响着催化剂的性能.采用水热合成法制备晶化时间不同的SBA-15，用等体积浸渍法制备负载型的Cs-La/SBA-15催化剂.利用XRD、SEM、IR、BET和TPD等手段对载体和催化剂进行表征，并评价相应的催化剂活性.结果表明，当晶化时间为24 h时，由于载体具有稳定的孔结构（孔径为6 nm左右）和大的比表面积（1 000 m2/g左右），且催化剂表面的中等强度碱性活性位的数量较多，导致催化剂的活性最好.当原料配比为MP/FA=1/1时，反应转化率达到30.9%，选择性达到90.3%.
王亚男 , 闫瑞一 , 李增喜 . 晶化时间对Cs-La/SBA-15催化丙酸甲酯与甲醛缩合反应的影响[J]. 中国科学院大学学报, 2016 , 33(6) : 741 -747 . DOI: 10.7523/j.issn.2095-6134.2016.06.004
Aldol condensation of methyl propionate (MP) and formaldehyde (FA) is a green and sustainable route to synthesize methyl methacrylate (MMA). The key to the route is to develop effective catalysts, and the supports of catalysts play an important role in the catalytic performance. SBA-15 with different crystallization time was synthesized by the hydrothermal method and the Cs-La/SBA-15 catalysts were prepared by wetness impregnation method. The catalysts were characterized by XRD, SEM, IR, BET, TPD, etc. The effect of crystallization time of SBA-15 on the catalytic performance of Cs-La/SBA-15 for aldol condensation was studied. The results showed that regular mesoporous materials with 2D-hexogonal rod-like structure were obtained when the crystallization time was more than 24 h. The Cs-La/24SBA-15 (with SBA-15 crystallized 24 h) exhibited higher catalytic activity than the other catalysts because of the higher density of medium base sites as well as the great surface area of SBA-15 (around 1 000 m2/g) and uniform pore size (6 nm). When the MP/FA=1/1, the conversion of MP is 30.9% and the selectivity of MMA reachs 90.3%.
Key words： crystallization time; catalysts; aldol condensation
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