Process for recovering dimethylnaphthalenes from cracked gas-oil by azeotropic distillation

A dimethylnaphthalene concentrate containing 2,6- and 2,7-isomers is obtained from a cracked gas oil containing dimethylnaphthalenes and boiling within the range 400-650 DEG F. by mixing with a polyalkylene glycol or a mixed ethylene glycol-propylene glycol ether and subjecting the mixture to azeotropic distillation and recovering dimethylnaphthalenes from the overhead. The gas oil preferably boils in the range 480-515 DEG F. and contains at least 40% aromatics. The glycol is preferably an aqueous diethylene glycol containing up to 20% by weight of water and is added in a ratio to hydrocarbon of 1-10 : 1. The mixture is distilled to remove material boiling below 450 DEG F. and from the bottoms is recovered, by further distillation, an overhead azeotrope boiling in the range 451-454 DEG F. In cooling to below 100 DEG F. the azeotrope separates into two phases; the glycol may be recycled and the dimethylnaphthalenes are recovered and separated by crystallization if desired.