Selective conversion of rice straw to xylose, glucose, and other products in H2O-SO2 system by two-step treatment

Rice straw is a renewable, cheap, and abundant resource in agriculture. Due to its controllable and recoverable properties, H2O-SO2 system was studied as a reaction medium to hydrolyze rice straw to produce chemicals by a two-step treatment. The first-step treatment converted hemicellulose to xylose (17.1%), glucose (3.1%) and arabinose (3.5%) at 140 °C. The second-step treatment converted cellulose to glucose (10.9%) at 190 °C. The total yield of products by the two-step treatment of rice straw was 41.1%, which is more than that in the one-step treatment (21.0% at 190 °C). The apparent activation energies for hemicellulose conversion and xylose dehydration were 76.7 and 66.9 kJ/mol, respectively. The degradation products obtained from the two-step treatment are less than that from the one-step treatment.