The Preparation Of FDCA From HMF By Dendrimer-like Silica Nanoparticles With Hierarchical Pores And Zirconium Framework

In this paper,modified nanoparticles of amino was prepared as the carrier for loading Pt,in case of Pt nanoparticles were reunited to affect the catalytic activity.Amino modified dendrimer-like silica nanoparticles with hierarchical pores(HPSNs-NH2)has the characteristics of homogeneous particle size,good morphology and large surface area.The condition of removing the template agent by extraction is also spent.It was found that the optimum concentration of HCL was 15ml,the template is removed completely and the structure of silica ball is good.After successfully preparing the HPSNs-NH2 material with large surface area and suitable load,we prepare Pt by two ways:sodium citrate method and sodium borohydride method.In order to enhance the ability to generate FDCA for oxidation of HMF we coated Zr framework on the surface of HPSNs-NH2.In order to further increase the surface area of the catalyst and the effective composition proportion,we use NaOH washing off silica nanoparticles structure and get the hollow structure Zr-HPSNs-NH2@Pt(KX_Zr-HPSNs-NH2@Pt)catalyst.The influence of KX_Zr-HPSNs-NH2@Pt catalyst on the preparation of FDCA byHMF under different conditions was explored.It was found that the conversion rate of HMF reached 100%and the yield of FDCA reached 98.3%at 70 C,mole ratio NaOH/HMF=2,10ml H2O,HMF=0.5mmol,25mg Zr@2.46nmPt reaction 12h.When the catalyst was used 5 times,the conversion rate and the FDCA yield of HMF were basically unchanged,which showed good stability.Through the study of the 12h conversion rate of the reactions and productions,it is found that the mechanism of aerobic oxidation of HMF to FDCA under the alkanline condition.First the HMF is oxidized to HMFCA.Second HMFCA is oxidized to FFCA.Finally,FFCA is oxidized to FDCA.