| 摘要 |
<p>PURPOSE:To separate indoles in good selectivity and high yield, by adding an extracting agent to coal based tar or liquefied oil containing indole and extracting components other than the indoles into a gas by a supercritical gas extraction method. CONSTITUTION:An extracting agent, e.g. amines, glycols, sulfoxides, particularly preferably monoethanolamine or ethylene glycol is added to a coal based tar or liquefied oil containing indole and a gas, e.g. gaseous carbon dioxide, 1-4C hydrocarbon gas, etc., is used to extract components other than indoles into the gas by using a supercritical gas extraction method to extract and separate the indoles. According to this method, purity and recovery ratio can be improved to shorten extraction time and a low cost is sufficient without corrosion of containers.</p> |
