Wash oil is the medium temperature fraction of coal tar at 230~300℃, which accounts for about 15% of the total coal tar. Has a strong foul smell. The price is very low. The composition of the washing oil is complex, mainly neutral components, such as methyl naphthalene, biphenyl, fluorene, indole, dimethyl naphthalene, methyl fluorene, etc., but also contains pyridine, quinoline and other basic components and acid Components. The color and smell of the wash oil is mainly derived from the unstable hydrocarbons, thiophenols, mercaptans, pyrrole, indole, quinoline, etc. in the wash oil.
