BATCHING-OFF OF NAPHTHALENE AND METHYLNAPHTHALENE FROM CRUDE METHYLNAPHTHALENE OIL

摘要

PURPOSE:To batch off efficiently a naphthalene component useful for vermin expellant, etc. and a methylnaphthalene component useful as solvent, etc., by adding a gamma-lactone and a polyalkylene glycol to a crude methylnaphthalene oil to be subjected to fractional distillation. CONSTITUTION:A gamma-lactones (e.g. gamma-butyrolactone) and a polyalkylene glycol (e.g. diethylene glycol) are added to a crude methylnaphthalene oil in an amt. of 20-500wt%. In the 1st-step distillation, an azeotrope of gamma-lactone and naphthalene is batched off and water is added to it to recover naphthalene that crystallizes out, by centrifugal separation, etc. Bottom of the 1st-step distillation is subjected to 2nd-step distillation to batch off an azeotrope of polyalkylene glycol and naphthalene. The azetrope is left at rest for separation into two layers and the upper methylnaphthalene layer is taken out for recovery, while the lower polyalkylene glycol layer is circulated for reuse.