A new two-step oxidative degradation method for producing valuable chemicals from low rank coals under mild conditions

Brown coal and lignite are abundant fossil resources,but they have several disadvantages such as low calorific value and high water content.: Consider ing that the coals consist of small aromatic ring structures with-many func tional groups, utilization methods reflecting the structure should be explo red. From this viewpoint we l;ave presented; a new method to produce chemic als: from brown coal and lignite under mild conditions. That is the oxidati on using 30%-H2O2 aqueous solution at 60 degreesC under atmospheric pressur e. When an Australian brown coal (Morwell)was oxidized for 24 h at 60 degre esC, the yield of water-soluble organics was as large as 0.60 kg/kg-coal, 0 .28 kg/kg-coal of which; were chemicals such as oxalic acid and acetic acid , On the basis of the examination of the structure of the water-soluble org anics, we also presented two methods for upgrading the water-soluble organi cs. One is the Fenton oxidation of the water-soluble organics by which the yield of Small-molecule components reached more than 0.50 kg/kg-coal: The o ther is the decomposition of the water-soluble organics in a sub-critical w ater by which 0.12 kg/kg-coal of benzene or 0.236 kg/kg-coal of methanol wa s produced, depending on the conditions employed;for preparing the water-so luble organics. Thus:it was clarified that the proposed methods' are effect ive to produce chemicals from brown coals with low energy supply.