Process for obtaining a pure hydrocarbon from a sump product of an

Abstract

Process for obtaining a pure hydrocarbon from a starting material containing the hydrocarbon including performing an extractive distillation of the starting material containing the hydrocarbon in an extractive distillation column using a solvent comprising an N-substituted morpholine having substituents with no more than seven carbon atoms; feeding the sump product of the extractive distillation column into a distillation separator column at an entry point in a center portion of the distillation separator column; distilling off the hydrocarbon from the top of the distillation separator column but advantageously returning a minor portion of it as a reflux; drawing off solvent from the sump of the distillation separator column; feeding the solvent drawn off from the sump of the distillation separator column into an evaporator to form a vapor in the evaporator at the pressure, p.sub.2, the pressure p.sub.2 in the evaporator being lower than the pressure p.sub.1 in the sump of the distillation separator column; condensing the vapor formed in the evaporator to form a condensate, feeding the condensate back to the distillation separator column and drawing off solvent as a liquid solvent from the sump of the evaporator and feeding back the liquid solvent to the extractive distillation column.