Hydrothermal processing of metal based compounds and carbon dioxide for the synthesis of organic compounds

Reservation of carbon-based resources including fossil fuel is an important issue for futuristic development. As a possible carbon resource, we had proposed a process for the reduction of CO₂ by hydrothermal method. In the process, CO₂, aqueous solvent, and reductant are to react under hydrothermal condition, to generate organic compounds. In this report, the extension of the process to continuous-type process has been focused. For the experiments, newly developed continuous-type equipment was used. Metallic materials such as carbon steel cutting chaff was treated at 200 °C, 2.0 MPa under the constant flow of CO₂ gas and solvent, with or without the hydrogenation catalyst, Ni. During the experimental period, reaction gas and liquid are collected successively. The samples are analyzed with GC and TOC. In treatment without Ni powder, organic compound was detected in neither reaction gas nor solution, while the occurrence of CO was confirmed. On the other hand, in the experiment with Ni powder additionally, formic acid was generated. It has been confirmed that the reaction process proceeds even in the continuous-type treatment including the catalytic effect of Ni.