Abstract: One-step method to produce reducing sugar by means of non-catalytic conversion of rice straw in supercritical water is a kind of new approach to produce fuel alcohol. A supercritical water batch-type system was designed in our laboratory. Rice straw samples in the reaction vessel were treated with this system in near critical or supercritical state of water at a designated treatment time by heating tin bath, and the reaction vessel was immersed in the water bath to quench the reaction at the end. It was found that the yield of reducing sugar can reach the maximum value 28.81 % in the condition of 350℃, 16 MPa, 25 s, solid liquid ratio 1:15 and non pretreatment of rice straw. In addition, using rice straw without any treatment as raw materials is more beneficial for non-catalytic conversion of rice straw in supercritical water than using rice straw treated with NaOH or NH₄OH.

Key words: supercritical water, rice straw, reducing sugar, fuel alcohol, non-catalytic conversion