摘要:
采用"机械混合-焙烧"方法制备了负载型固体碱催化剂MgO/NaY,研究了糠醛与丙酮在水-乙醇体系中的羟醛缩合反应,考察了催化剂负载量、原料配比、反应温度、反应时间等因素对催化剂性能的影响。结果表明,20%MgO/NaY催化剂表现出最佳的催化性能,在85℃条件下反应8 h后,糠醛转化率达到99.6%,亚糠基丙酮(FA)和二亚糠基丙酮(F2A)选择性分别达到42.2%和57.1%,缩合产物的总收率为98.6%。高温促进反应中间体向产物的转化,有利于提高产物的总选择性。改变糠醛/丙酮的摩尔比可调控两种缩合产物的选择性,较高的糠醛/丙酮摩尔比有利于提高F2A的选择性,但会降低整体反应速率。重复性评价表明,催化剂具有较好的再生性能。
Abstract:
MgO/NaY catalyst was prepared by a simple and green procedure and used in the aldol condensation of furfural and acetone to produce jet fuel intermediates in a water-ethanol solvent; the effects of MgO loading, feedstock composition, reaction temperature and time on the product distribution were investigated. The results indicated that the 20%MgO/NaY catalyst performs best in the aldol reaction; the conversion of furfural reaches 99.6% after reaction at 85℃ for 8 h, while the selectivities to furfural-acetone (FA) and di-furfural-acetone (F2A) are 42.2% and 57.1%, respectively, with a yield of condensation products of 98.6%. High temperature may enhance the degradation of F3A2 intermediate and therefore improves the selectivity to aldol products. The product distribution can be adjusted by changing the feedstock composition; the selectivity to F2A increases with the increase of the ratio of furfural to acetone, at the expense of a slight decrease of the reaction rate. The spent catalyst shows a good regeneration capability; its catalytic activity is well recovered after calcination treatment.
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