Purification Of 2,5-furandicarboxvlic Acid

2,5-Furandicarboxylic acid(FDCA),a kind of biomass-based platform compound,can be producted by oxidation of 5-hydroxymethylfurfural(5-HMF).As an alternative monomer of terephthalic acid(PTA),FDCA can ben polycondensed with ethylene glycol(EG)to produce polyethylene furandicarboxylate(PEF),which is an ideal substitute for petroleum-based polyester PET,with better gas barrier,biocompatibility and mechanical properties.During the oxidation of 5-HMF to FDCA,some impurities can be precipitated together with FDCA products.That can further affect the subsequent polyester reaction and the quality of PEF products seriously.Therefore,the crude oxidation FDCA must be purified into high-purity FDCA product.In this work,exploratory experiments were carried out to investgate the FDCA refining methods and the basic solid-liquid equilibrium data were measured.All the results of this work included:1)The solid-liquid phase equilibrium of FDCA in acetic acid-water was determined by experiments,and the parameters of the FDCA solid-liquid equilibrium model were obtained.2)The feasibility of hydrogenation and recrystallization was verified,and the hydrofining method over Pd/C catalyst was investigated further to get higher-purity polymer grade FDCA products.The hydrogenation reaction conditions,such as the reaction time,temperature,pressure and the catalyst dosage was optimized.3)According to the characterization of the FDCA crystal structure and the oxidation reaction-crystallization,the affinity incorporation mechanism of the co-crystallization of impurities(FFCA and FCA)into FDCA solid was proposed.The basic data and alternative methods in this work may be helpful for the industrial technology development of the purification FDCA process.