Study On Preparation And Catalytic Performance In Michael Addition Reaction Of Nano KF/Al₂O₃

Common KF/Al2O3 as a kind of solid base catalyst has been employed in a variety of organic reactions types with high yields. With many merits involving, e.g., easier preparation, cheapness, easier storage, mild catalytic conditions, easier postwork, and high stereoselectivity, it becomes a new environmental protection catalyst, so it has been studied by scholars gradually. But so far it has been obscure of KF/Al2O3s surface morphology, catalytic mechanisms, optimum conditions of catalyses, and so on. Moreover, we further study how to improving the catalytic performance by itself, broadening the range of application and renewing the manner of application. The nano KF/AbOa catalyst in this paper is a studying route under this thought. It increase the surface area, improve the adsorptive capacity, make KF dispersed better, so it is a kind of solid strong base owning strong basicity and nucleophilicity.In this paper , nano solid base KF/Al2O3 has been prepared by immersing nano Y -AhOa powder into KF solution. The effects of supports, immersing solvent, immersing temperature, and surface-active agent to particles size were studied. It should be concluded that the nano y -AbOa support, the ethanol solvent, the 65 immersing, PEG6000 and PEG400(1:1) as surface active agent give the best result, and obtain the 20~40nm particle.This paper selects the preparation of (2-cyanoethyl) malonic acid diethyl ester as characterization of catalytic performance. In the Michael additions, the above preparation conditions and the loadings of KF, quantities of catalysts, calcining temperature, reactions times, reactants ratios affect reactions. By some studies, it can be concluded that the Z-5 loading, the O.OSmol equivalent catalyst, the 400 癈 calcining, 1.5 hours' reaction, malonic ester: acrylon=3:l get the best result, and obtain the yield of 93.3%. In addition, the inorganicsupport- A^Os can be reused 5 times with high activity at least, so it lowers the cost of catalyst.Employing nano- KF/AhOs, I prepare ?-subsstitutedamino( azoticheterocycle )- propionate. Because of increasing the surface area, improving the adsorptive capacity, making KF dispersed better, adding the basic capacity, nano-KF/AbOa has higher yield more than common KF/AbOs. In addition, by several series experiments I have done, I can say that the Z-5 loading gives the best catalytic results in Michael addition.This paper associates the characterization of nano- KF/A^Oa to study the catalyst's activity mechanism in Michael addition. By a series of techniques of characterization, e.g., transmission electron microscope (TEM) analyses, Infrared spectrum (I.R) analyses, powder X-ray diffraction (XRD) analyses,, X-ray photoelection spectrometry (XPS) analyses, temperature programmer desorption (TPD) analyses, It can be confirmed that nano KF/AlaOs catalyst is a kind solid strong base owning three basic sites, two of which are key functions. One could be the KsAlFn, the other could be the [A1-OH---F"] species.Researching results from this article establish a new route to improve the catalyst activity by itself, give powerful evidences to define basic sites of nano- KF/AfeOs, and provide important information about the mechanisms and the optimum conditions of catalyzing Michael additions, and put forward a rational improvement of the syntheses of P -subsstitutedamino( azotic heterocycle )- propionate.