Abstract: Liquefaction of coconut fiber assisted via microwave irradiation was carried out with the mixture of macrogol 400(PEG-400) and glycerol(Gl) as liquefied reagent and concentrated sulfuric acid as catalyst. The liquefaction rates were obtained at different reaction time, amount of catalyst, temperature, the mass ratio of PEG-400 and Gl and the mass ratio of liquefied reagent and coconut fiber. The results showed that the optimal conditions for the liquefaction were liquefied reagent and coconut fiber mass ratio 5:1, the amount of sulfuric acid 3%(relative to the mass of liquefied reagent), reaction temperature 160℃, reaction time 20 min, PEG-400 and Gl mass ratio 4:1, the highest liquefaction rate was 88.83% under these conditions. And the viscosity(25℃) and density(20℃) of liquefied product were 0.235 Pa·s and 1.084 g/cm³. According to the different reaction time, the molecular weight of the liquefied products were analyzed by GPC. The results showed that weight average molecular mass and dispersion coefficient increased gradually with the increase of reaction time. The infrared spectroscopy analysis showed that during the liquefaction, the cellulose, lignin and some aliphatic hydrocarbon were liquefied and the liquefied product with abundant hydroxyl was obtained and some of the cellulose and lignin in the liquefaction residue was still not liquefied.

Key words: coconut fiber, liquefaction rate, product analysis