| 摘要 |
A process for separating a butene-1/isobutene mixture from a C4 hydrocarbon fraction is provided which comprises subjecting the C4 hydrocarbon fraction to extractive distillation using a polar solvent to separate components predominantly containing 1,3-butadiene as an extract and obtain an overhead containing butanes, butene-1, isobutene and butene-2 as main components and being substantially free from C3-C4 diolefinic and acetylenic hydrocarbons, feeding the overhead into a first distillation column, removing isobutane as an overhead component from the first distillation column, feeding high-boiling components from the bottom of the first distillation column to a second distillation column, removing n-butane and butene-2 from the bottom of the second distillation column, and obtaining highly pure butene-1 and isobutene from its top. When isobutene contained in the overhead in the above process is removed in the form of tertiary butyl alcohol or tertiary butyl ether before it is fed into the first distillation column, highly pure butene-1 alone is obtained from the top of the second distillation column.
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