| After decades of continuous development,biomass chemicals,as an important renewable resource,are gradually entering people’s daily life from the laboratory.Researchers turn their attention from the study of chemical behavior of biomass to the development of more efficient preparation process and detection methods to ensure its safety.Ferrite magnetic nanocomposites are widely used in many fields,such as catalysis,adsorption,and separation.In this paper,a series of ferrite magnetic nano materials were designed and prepared,and their applications in the catalytic preparation,separation and detection of high value-added biomass chemicals were studied,mainly including the following contents:Part Ⅰ:The preparation process of magnetic ferrite supported copper nanoparticles was introduced,and the composition of the catalyst was characterized.The catalytic conversion of furfural to cyclopentanone（CPO）and Cyclopentanol（CPL）in water was studied systematically.The effects of copper loading,reaction time and hydrogen pressure on the product distribution of CPO and CPL were studied.Then the reaction process and mechanism were discussed.The highest yield of CPO was 91%at 3 MPa H2,10%Cu/Fe3O4 443 k and 4 h.The highest yield of CPL was 82%at 3MPa H2,50%Cu/Fe3O4 443 k and 3 h.The catalyst can be reused for 5 times without obvious activity loss.The catalyst is easy to use,simple to prepare,and has obvious application prospects.PartⅡ:Study on Fe3O4@Si O2@m Si O2-Ta OPO4 magnetic nano catalyst and its catalytic hydrolysis of fructose to 5-HMF.Tantalum tartrate was used as tantalum source to react with diammonium hydrogen phosphate,so that tantalum was loaded into the pores of the outer layer of the nanocomposite,and the catalyst was obtained by calcination at high temperature.The structure of the catalyst was characterized by FT-IR,TEM,EDS,SEM,XRD and VSM.It is determined that the composite is spherical and has a uniformly ordered core-shell mesoporous structure and high saturation magnetization,amorphous tantalum phosphate is evenly distributed in the outer mesoporous channels.The catalytic activity of the catalyst for the hydrolysis of fructose to HMF was systematically studied.The effects of solvent type,catalyst type,reaction time,reaction temperature and amount of catalyst on the yield of HMF were determined.The results showed that using 20 wt%catalysts,fructose was hydrolyzed in a two-phase system composed of 2-pentanol and water.After reaction at 120°C for 2 h,the yield of HMF was up to 85.4%.The catalytic system has stable structure and no significant decrease in catalytic activity after seven cycles.The scale-up experiment of15 g fructose was carried out,and the total yield of 51.3%HMF was obtained,which showed the industrial application potential of the catalytic system.PartⅢ:Study on Fe3O4@Si O2@m Si O2-NH2-Cu（Ⅱ）magnetic nano catalyst and its synergistic TEMPO catalytic oxidation of 5-HMF to DFF.Magnetic core-shell mesoporous nanocomposites were constructed by improved St（?）ber method,grafted with amino groups to form N,N-bidentate coordination structure,impregnated with copper salt and dried to obtain Fe3O4@Si O2@m Si O2-NH2-Cu（Ⅱ）.The structure of the catalyst was characterized by FT-IR,TEM,EDS,SEM,XRD,BET and VSM.It is determined that the composite is spherical and has a uniformly ordered core-shell mesoporous structure and high saturation magnetization,and amino groups and Cu are evenly distributed in the mesoporous channels.The synergistic catalytic system composed of the composite and TEMPO was systematically studied to catalyze the oxidation of HMF to DFF in oxygen or air.The effects of solvent type,reaction time,reaction temperature and amount of catalyst on HMF conversion and product selectivity were determined.The results showed that when the oxygen pressure was 1atm and 50°C for 18 h the conversion of HMF was 93.4%and the highest yield of DFF was 92.4%.The catalyst was reused for 5 times and still maintained good activity,showing good reusability.The study of oxidation reaction mechanism shows that the reaction may be carried out through free radical reaction mechanism.The results of substrate expansion test show that the system has good substrate adaptability.PartⅣ:The preparation and characterization of magnetic core-shell mesoporous surface molecularly imprinted polymer nanocomposite（Fe3O4@Si O2@m Si O2-MIPs）are introduced.Based on this nanocomposite as magnetic solid phase extraction materials,a rapid,efficient and sensitive matrix dispersion magnetic solid-phase extraction mass spectrometry method（MSPE-MS）was developed for the determination of phthalate esters（PAEs）and furanedicarboxylate esters（FDCEs）.The results show that the composite has obvious core-shell structure,spherical distribution,large specific surface area and high magnetic saturation strength,and has excellent recognition performance for molecularly imprinted target compounds,and the material has good reusability.The samples were extracted by magnetic composite solid phase extraction and separated by external magnetic field,and then determined by GC-MS/LC-MS.The method has low detection limit and high precision,and is suitable for the determination of trace PAEs and FDCEs in liquid packaging materials.Part Ⅴ:Aqueous two-phase extraction of egg yolk lecithin and its application in the preparation of Fe3O4 nanoparticles.High purity egg yolk lecithin was prepared from egg yolk powder by aqueous two-phase extraction.The phase equilibrium and the factors affecting the extraction effect were investigated to determine the optimal extraction conditions.The obtained high-purity egg yolk phospholipids were tested according to the quality standards specified in the Chinese Pharmacopoeia.The results showed that the content of phosphatidylcholine was more than 80%,and the peroxide value,acid value and other physical and chemical indexes met the requirements specified.Compared with the prior art,the extraction method has the advantages of mild conditions,simple operation,high product purity,more friendlily to the environment,and meets the requirements of green chemistry.It provides a feasible new choice for the industrialized preparation of pharmaceutical grade egg yolk lecithin.The obtained high-purity egg yolk lecithin was used as surfactant in the preparation of Fe3O4nanoparticles.The results showed that the effect of high-purity phospholipids was much better than egg yolk powder and crude phospholipids with low content of phosphatidylcholine,and the morphology of Fe3O4 nanoparticles prepared with PVP as dispersant was similar,indicating that high-purity egg yolk phospholipids have the potential to be used in the preparation of Fe3O4 nanoparticles,which is worthy of further study. |
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