Abstract: The rice straw was liquefied by microwave heating in the mixture of phenol and glycerol as the liquefying reagents with sulfuric acid catalytic. This paper discussed the effects of different factors on residue rate. The result showed that 7.17% of residue rate remained under the optimum conditions, i.e., microwave power of 500 W, the liquid-solid ratio of 7:1, the mass ratio of phenol and glycerol of 4:1, sulfuric acid amount of 5%, the temperature of 150 ℃ and reaction time 22.5 minutes. The results of GPC showed that with the extension of liquefied time, the relative molecular weight appears decreasing, but of the distributions, increased a bit. From the IR spectrum, it was concluded that the cellulose and hemicellulose are easier to be dissolved and the main ingredients of liquefaction residues are lignin and its derivatives.

Key words: rice straw, liquefaction, microwave-assisted