SEPARATION OF HIGH PURITY BUTENE-1 OR BUTENE-1/ISOBUTENE MIXTURE FROM 4C HYDROCARBON FRACTION

摘要

PURPOSE:To obtain the titled compound useful as a comonomer for polyethylene polymerization, from a 4C hydrocarbon fraction, in high purity, in large quantities, at a low cost, by using a combined process comprising an extractive distillation step using a polar solvent and two distillation steps. CONSTITUTION:The 4C hydrocarbon fraction 1 is subjected to the extractive distillation A-1 using a polar solvent to separate a component composed mainly of 1,3-butadiene as the extract 4 leaving the raffinate 3 composed mainly of butanes, butene-1, isobutene, and butene-2 and free from 3-4C diene and acetylene hydrocarbons. If necessary, after removing (D, E) isobutene in the form of t-butyl alcohol, the raffinate is distilled in the first distillation column B to separate n-butane and butene-2 as the bottom component 8. The low boiling component 7 obtained from the top of the column is sent to the second distillation column C to remove isobutane 9 from the top and obtain the high-purity titled compound 10 from the bottom.