|Budget Amount *help
¥2,500,000 (Direct Cost : ¥2,500,000)
Fiscal Year 1997 : ¥900,000 (Direct Cost : ¥900,000)
Fiscal Year 1996 : ¥1,600,000 (Direct Cost : ¥1,600,000)
The present project has been aimed at developing anodic conversion of coal as a commercial process producing starting materials for C_1 chemical industries. To clarify fundamental properties of the anodic coal conversion, it is studied how kinds of supporting-electolyte, of coal and of mediator affect rate of coal conversion and of C_1 gas formation. In the course of the study, the property of generation and decomposition of humic acids, principal and intermediary products of the coal conversion, was noticed affecting severely both rate of the coal conversion and efficiency of C_1 gas formation. Thus both the above property of humic acids and the fundamental property of the coal conversion were analyzed and the following were obtained :
i) The coal conversion was rate-controlled by a step of the dissolving of humic acids into supporting-electrolyte, thus proceeding anodically faster at basic supporting-electrolyte than at acidic one because of the faster dissolving of the humic acids in
basic one and at a younger coal than at an older one.
ii) The coal decomposition proceeded at a series mechanism in which the humic acids generated at first, then decomposing to lower molecular weight humic acids and finally degraded to C_1 gases.
iii) Owing to the series mechanism, amounts of generated C_1 gases were affected severely by kinds of supporting-electrolyte, being greater at acidic one and under the influence of mediator with a higher redoxpotential. Yields of the C_1 gases were about 10% during a run time of 50 h when Mn^<31>/Mn^<21>, the most active in acidic supporting-electrolyte among the mediators investigated, was used.
iv) The principal humic acids generated far more in basic supporting-electrolyte than in acidic one. Their yields were about 70% during a run time of 50 h. Their molecular weights distributed widely, but was able to be concentrated at 1.0*10^4 - 5.0*10^4 when the electrolytic conditions were chosen suitably.
v) Interfacial activity of the principal humic acids depended on their molecular weight, being higher than humic acids extracted from coals with basic aqueous solutions or commercial ones. Thus the principal humic acids have a bright prospect as a agent, e.g.agent stabilizing Coal-Water-Mixture. Less