Study On The Conversion Of Biomass-derived Platform Chemical Levulinic Acid Into Diphenolic Acid

In recent years, biomass is considered to be renewable resources in nature to replace the fossil resources for the production of fuels, chemicals. And levulinic acid (LA) is just one of the most important biomass derivatives. It is a significant pathway for the utilization of biomass through converting levulinic acid into diphenolic acid (DPA). According to the current research progress, a series of studies was carried out for the synthesis process of DPA in this dissertation, including the preparation of novel catalyst and new technology for heating.Firstly, tungstophosphoric acid was used as a catalyst for the synthesis of DPA from levulinic acid and phenol, and it exhibited a good catalytic effect under the following reaction conditions:the molar ratio of LA and phenol was1:5, the molar ratio of tungstophosphoric acid and LA was1:25,100℃,24h. A DPA yield of42.47%was achieved.Secondly, a novel catalyst was prepared from tungstophosphoric acid and ionic liquids, and it was characterized by Scanning electron microscopy (SEM), Fourier transform infraredspectroscopy(FT-IR), X-ray photoelectron spectroscopy(XPS), nuclear magnetic resonance (NMR) and thermogravimetry(TG). The assembled catalyst has been employed for synthesis of DPA from LA and the reaction parameters (such as molar ratio of levulinic acid and phenol, reaction temperature, reaction time and catalyst loading dosage) have been optimized.. The optimum conditions for synthesis of DPA from LA are:the molar ratio of LA and phenol was1:4, the molar ratio of catalyst and LA was1:25,100℃,24h. the yield of DPA came up to41.67%..Eventually, microwave irradiation with the assistance of ultrasound was employed as a particular heating mean in the condensation of LA into DPA, and the influencing factor of microwave power and reaction temperature were explored. Compared with traditional heating, the reaction time could be sharply shortened via microwave irradiation with the assistance of ultrasound.Above all, tungstophosphoric acid and novel catalyst ([MIMPS]3PW12O40) were employed as green catalyst in the condensation of LA into DPA, a new heating method of microwave irradiation with the assistance of ultrasound was studied with a reaction time of15min. These findings provided some valuable information for further researches of DPA.