Alireza Salabat - Chemistry Department, Arak University, P.O. Box ۳۸۱۵۶-۸۷۹, Arak, Iran
Mohammadreza Nemati

Extractive distillation is the method of separating close boiling compounds or azeotropes, by carrying out the distillation in a multi-plate rectification column in the presence of an added liquid or liquid mixture, which liquid(s) having a boiling point higher than the compounds being separated. The extractive agent alters the relative volatility of the close boiling compounds to make possible a greater degree of separation. The extractive agent should boil higher than any of the close boiling liquids being separated and not form minimum azeotropes with them. This usually requires that the extractive agent boil twenty Centigrade degrees or more than the lowest boiling component [1].