| 摘要 |
PURPOSE:To remove dihydromethylbenzothiophene formed as a by-product in desulfurizing and purifying methylnaphthalene with anhydrous aluminum chloride and improve the desulfurization ratio, by distilling away the above- mentioned by-product and obtaining a methylnaphthalene fraction. CONSTITUTION:Anhydrous aluminum chloride is added to methylnaphthalene oil containing methylbenzothiophene as an impurity and the methylnaphthalene oil is heat-treated. The aluminum chloride is then extracted and removed with water or sulfuric acid solution etc., to produce the aimed purified methylnaphthalene by distillation. In the process, >=5% metylnaphtnalene, together with respective above-mentioned by-product (hydrogenated substance of the above-mentioned impurity), is distilled by using a distillation column having >=30 number of theoretical plates at >=10 reflux ratio as a fore-running in batch distillation or using a distillation column having >=50 number of theoretical plates at >=30 reflux ratio as an overhead fraction in continuous distillation to distil away the above-mentioned by-prouct. The aimed methylnaphthalene is obtained to almost completely remove the above-mentioned by product and improve desulfurization efficiency.
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