| 摘要 |
<p>The invention relates to a method for producing phthalic anhydride according to specifications by the distillative purification of crude phthalic anhydride. According to said method, crude phthalic anhydride is fed to a distillation column which is operated at a reduced pressure, then the lowboiling constituents at the head or in the vicinity of the head of the distillation column are removed and the phthalic anhydride which conforms to specifications is recovered from the column through a lateral vent.</p> |
