methods for the extraction of isoprene using aqueous n formylmorfoline and / or morfoline.

摘要

A multi-stage method is disclosed whereby isoprene of high purity is recovered from mixtures of C5 hydrocarbons containing it, wherein the mixture is subjected to a first extractive distillation stage in the presence of a solvent, such as morpholine and N-formyl-morpholine, containing water and in which olefinic and saturated hydrocarbons are withdrawn as a top product; a second extractive distillation stage effects the withdrawal of the major part of the cyclopentadiene and acetylene compounds present in the bottom product of the first stage as a sidestream and said solvent constitutes a bottom product for recycling to said first and second stage; in a third extractive distillation stage the top product of the second stage is treated with solvent containing water, fed to the third stage from a stripper and then recycled as bottom product to said stripper; and, in a rectification stage, isoprene of desired purity is recovered from the overhead product of the third extractive distillation stage.