Process for recovering processing liquids

A process for recovering a processing liquid from a feed mixture comprising water, a processing liquid having a higher boiling point than water, and at least one component that is less volatile than said processing liquid, comprising:

• providing a stream of said feed mixture;
• introducing said stream of said feed mixture into a first heating zone and initially heating said feed mixture to a temperature sufficient to volatilize at least some of said water and at least a portion of said processing liquid, said temperature in said first heating zone being below the decomposition temperature of said processing liquid, to produce a vapor stream comprising said volatilized water and said volatilized portion of said processing liquid, and a residuum comprising said processing liquid and at least some of said at least one less volatile component;
• separating said vapor stream from said residuum in a first separation zone;
• passing at least a portion of said residuum through a second heating zone at a temperature below the decomposition temperature of said processing liquid to produce a heated, first recycle stream;
• reducing the concentration of said less volatile component in said residuum;
• admixing said heated recycle stream with said stream of said feed mixture to effect said initial heating of said feed mixture;
• treating said vapor stream to recover a water stream and a purified processing liquid stream;
• separating said purified processing liquid stream into a low boiling liquid fraction and a high boiling fraction;
• and
• admixing, by recycle, at least a portion of at least one of said water stream, said high boiling fraction, and said low boiling fraction with said stream of said feed mixture.