| 2,5-Furandicarboxylic acid(FDCA)is a biomass monomer with high added value,which can be used as a substitute for terephthalic acid to produce packaging materials,beverage bottles,films,fibers and other products.At present,the research on the synthesis of FDCA is mainly focused on the development of catalyst,while the research on the optimization of reactor is scarce.Most scholars used batch tank reactors for catalytic oxidation to synthesize FDCA.Although the reaction can proceed quickly in some catalytic systems,the reaction still costs a couple of hours due to the limitation of mass transfer in batch tank reactors.Therefore,it is particularly important to explore an efficient synthesis method of FDCA.In recent years,micro-chemical technology has developed rapidly.Its excellent mass and heat transfer characteristics,continuous and efficient production performance,safe and reliable production characteristics provide new ideas and methods for the synthesis of FDCA.In this paper,aiming at the reaction process of synthesis of FDCA by catalytic oxidation of 5-hydroxymethylfurfural(HMF),two microstructure equipments,slurry microfluidic reactor and micro-packed bed reactor,were designed and used to optimize the reaction process.In this paper,a slurry microfluidic reactor was designed and made,that is,solid catalyst particles and liquid participate in the reaction in the form of slurry,and then form a gas-liquid-solid three-phase reaction system with oxygen.In this system,the catalyst was screened,and influence of reaction liquid concentration,type and amount of alkali,residence time and gas-liquid ratio on the reaction was determined.In the slurry microfluidic system,we used Au/CeO2 as catalyst,a gas-liquid ratio of 10,and a HMF/NaOH molar ratio of 4,the reaction time is 10 min,0.025 mol/L HMF was converted 100%,and FDCA selectivity is 77.4%.In this paper,a micro-packed bed reactor was designed and fabricated.Through pulse tracer method and MATLAB software,it was determined that the fluid in the system was close to plug flow.By optimizing the reaction conditions,it was found that when gas-liquid ratio was 70,gas flow rate was 14 mL/min,liquid flow rate 0.2 mL/min,residence time 72 s,90℃ and 0.3 MPa conditions,the conversion of HMF can be 100%,and the selectivity of FDCA was 82%.At the same time,comparison showed that reaction performance of the micro-packed bed reactor was 45 times of the batch tank reactor.In addition,after eliminating the influence of internal and external mass transfer,kinetic parameters were determined,and it was concluded that the process of oxidation of 5-hydroxymethyl-2-furancarboxylic acid(HMFCA)to 5-formyl-2-furoic acid(FFCA)was the speed control step of the reaction. |
