Preparation Of Ag-Cu/hydrotalcite Catalyst And Its Application In The Transesterification Of β-ketoesters

β-keto ester is an important organic intermediate during the organic synthesis with physiological and pharmacological, such as a significant pharmaceutical intermediates product cinnamyl acetoacetate, which can prevent arteriosclerosis and other functions. β-keto ester can be achieved through the transesterification of esters and alcohols. Therefore, it is the significance to design an efficient heterogeneous catalyst for the synthesis of β-keto ester. The Ag, Cu metal nanoparticles were loaded on different supports, including the activated carbon (AC), γ-Al2O3, MgO, Mg-Al hydrotalcite (HTs) (Mg:Al= 1:1-10:1), to obtain the supported catalyst using the sol-gel immobilization method. The obtained catalysts were characterized via the techniques of XRD, BET, TEM, STEM (EDS), SEM (EDS), XRD, ICP-MS, AAS to study the particle size, morphology, composition structure of catalysts.The catalytic performance of catalyst was discussed by the transesterification of cinnamic alcohol and ethylacetoacetate.The effect of supports for the catalytic properties of catalyst shows that the acid and basic of supports can affect the yield of product. When the support is a strong acid support (γ-Al2O3) or basic support (MgO), the yield of products is much lower compared with other supports. The molar ratio of Mg, Al can also influence the yield. When the Mg:Al molar ratio was 5:1, the highest catalytic activity was achieved. And then, the molar ratio of Ag, Cu also studied that the catalyst has the highest activity when the Ag, Cu molar ratio was 1.2:1. At same time, the preparation methods of catalyst were also studied that the method of sol-gel immobilization is much better than other methods, which can obtain smaller catalyst particle size (about 4 nm) with evenly distributed.The study of reaction conditions, such as the amount of catalyst, time, temperature and solvent, was studied. The optimal conditions can be obtained when the amount of catalyst, time, temperature and solvent were 0.05 g,6 h,110 ℃ and DMF separately, which Ag-Cu/HTs catalyst have best catalytic activity.As for the stability of the catalyst, the structure and activity of Ag-Cu/HTs catalyst did not change a lot after 40 days, especially the valence of Cu, which indicted that Ag- Cu/HTs catalyst has high stability. After 6 times using, the catalytic activity did not decrease apparently.Finally, the Ag-Cu/HTs catalyst was used in the transesterification of a series of alcohols and various esters. High yields were obtained, which show the high activity of Ag-Cu/HTs catalyst.