| 摘要 |
<p>PROBLEM TO BE SOLVED: To efficiently and selectively decompose various synthetic polymers abundantly included in an industrial or home waste material and enable to recover a reusable low-middle molecular weight compound without inducing a trouble in the conventional technique such as troublesome in the treatment by selectively heat-decomposing a synthetic polymeric compound by using water in a supercritical or a subsupercritical state as a solvent. SOLUTION: A synthetic polymeric compound is selectively heat-decomposed by using water in a supercritical or a subsupercritical state as a solvent. Preferably, the heat-decomposing reaction is performed at 200-800 deg.C and under 2-90 MPa pressure for forming the water in the supercritical or the subsupercritical state. A small amount of acid is added to the reactive system so as an acid concentration of <=0.05% to be effective for increasing the yield and is preferable because of avoiding corrosion of equipment and readily removing the acid. As the synthetic polymeric compound, e.g. polyethylene, polystyrene or polypropylene is exemplified.</p> |
