Study On Catalytic Oxidation Of Glycerol With Supported Gold Catalysts Synthesized By Mechanochemical Method

Biodiesel is considered to be a promising renewable energy because of its advantages of easy availability of raw materials,environmentally friendly and renewable,and high safety performance.With the large-scale production of global biodiesel,the output of glycerol has also increased on a large scale.If the by-product glycerin is not effectively treated,it will cause new pressure on the environment and reduce the economic benefits of biodiesel.Therefore,the glycerol is converted Downstream products with high added value have become a hot spot of common concern in academia and social production departments.Among the many ways of deep processing of glycerol,the selective oxidation of glycerol to prepare 1,3-dihydroxyacetone（DHA）is considered to be an important direction,which has attracted more and more researchers’attention in recent years.However,in the current research on the preparation of DHA by glycerol heterogeneous catalysis,whether it is the preparation and loading of active centers and the preparation of carriers,a large number of chemical reagents will inevitably be introduced,which causes environmental problems and also seriously affects the use of DHA in drugs.And food applications.Therefore,in order to solve this problem,this study successfully prepared Cu O and Cu O-Co₃O₄ carriers by mechanochemical methods with the assistance of SBA-15,and successfully prepared gold nanoparticles through the green synthesis method-plant reduction method.It was supported on the prepared Cu O,Cu O-Co₃O₄ carrier,and the influence of the preparation conditions of the catalyst on its catalytic oxidation performance of glycerol was investigated,and the optimal process conditions for the glycerol oxidation reaction were obtained.In addition,through XRD,TEM,TG,XPS,BET and other characterization methods,the pros and cons of the catalyst’s catalytic performance and the different internal mechanisms during the preparation process were explored.The main conclusions are as follows:（1）The CuO carrier was successfully prepared by mechanochemical method,and the optimal preparation conditions were determined.The spherical mass ratio was 1:15,the milling time was0.5 h,and the calcination temperature was 500℃.With the aid of SBA-15,Au/Cu O catalyst was prepared by plant reduction method and used in the catalytic oxidation of glycerol.It was finally determined that the addition amount of SBA-15 was 0.4 g,and the active center Au loading amount was 1%.The catalyst has the best catalytic performance.The conversion rate of glycerol is 97.65%and the selectivity of DHA is 90.37%at 100℃and the molar ratio of glycerol to active center is100:1.The introduction of SBA-15 changed the morphology and physical properties of Cu O.The supported gold nanoparticles are small,and the strong interaction between the active center and the carrier is an important reason why the catalytic performance of the catalyst prepared by the mechanochemical method is better than the catalytic performance of the catalyst prepared by the traditional chemical method,and it is speculated that the agglomeration of active centers may be an important reason for the deactivation of the catalyst.（2）In the process of preparing Au/CuO-Co₃O₄,it was determined that the final loading method was AR method,and the optimal plant matter concentration required was 2 mg/ml.During the preparation of the carrier,it was determined that the optimal heat treatment temperature was 500℃,the mass ratio of Cu O and Co₃O₄ was 90-10,and the optimal addition amount of SBA-15 was 1 g.The optimal reaction temperature is 100℃,the optimal reaction time is 2 h,and the optimal reaction pressure is 1 MPa.Under these conditions,the conversion rate of glycerol was 57.89%,and the selectivity of DHA was 80.29%.