Preparation Of2,5-furandicarboxylic Acid And Its Polyesters

2,5-Furandicarboxylic acid(FDCA) as a new bio-based raw material was synthesized with5-hydroxymethylfurfural(HMF) in the presence of potassium permanganate under alkalosiscondition.2,5-Furandicarboxylic acid(FDCA) and terephthalic Acid (PTA) in differentproportions with ethylene glycol(EG) as the raw material and tetrabutyl titanate as the catalystwere used to prepare the poly(ethylene terephthalate-co-ethylene2,5-furandicarboxylate)(PEFT)through the direct esterification and melt-state polycondensation.2,5-Furandicarboxylicacid(FDCA) and terephthalic Acid(PTA) in different proportions with1,4-butylene glycol(BDO)as the raw and tetrabutyl titanate as the catalyst were used to prepare the poly(1,4-butyleneterephthalate-co-ethylene2,5-furandicarboxylate)(PBFT) through the direct esterification andmelt-state polycondensation. The structure and purity of FDCA and the structure, thermalbehaviour and intrinsic viscosity of PEFT and PBFT have been studied. The results obtainedwere as follows:FDCA was analysed via IR,1H NMR, HPLC. And the factors during the synthesis of FDCA,such as the reaction time, the concentration of NaOH solution, the molar ratio, were studied.After systematical experiments, the optimized reaction conditions were: the concentration ofNaOH solution was1.7mol/L, n(potassium permanganate): n(5-hydroxymethylfurfural)=2.4:1,the reaction time was40min, the reaction temperature was25℃, the2,5-furandicarboxylic acidyield was54.65%, the purity was99.5%.The peak of several functional groups, such as the carbon-carbon double bond of the furanring and the benzene ring, the ester group, the furan ring could be recognized in the IR. Thebehaviour of PEFT was studied about the intrinsic viscosity, DSC, TG and so on. With thecontent of FDCA in PEFT increased, the intrinsic viscosity of PEFT decreased gradually; theglass-transition temperature(Tg) increased apparently, but the crystallization temperature couldn’tbe recognized easily. The peak of several functional groups, such as the carbon-carbon double bond of the furanring and the benzene ring, the ester group, the furan ring could be recognized in the IR. Thebehaviour of PBFT was studied about the intrinsic viscosity, DSC, TG and so on. With thecontent of FDCA in PBFT increased, the intrinsic viscosity of PBFT decreased gradually; thecold crystallization temperature(Tcc) increased apparently, the thermal crystallizationtemperature(Tmc) and the melting point(Tm) reduced noticeably; the thermal decompositiontemperature shows a decline trend.Finally, the technological parameters and properties of PEFT and PBFT in the sameFDCA/PTA molar ratio were compared, and the anticipated and reasonable results have beengained.