| abstract |
Isobutene is extracted from 4C hyrocarbon mixts. by reaction with isobutanol in presence of an acid condensing agent, sepn. of the tert. ether formed and decomposition at elevated temp. in presence of an acid catalyst. Used for treatment of 4C fractions from ethylene plants or butane/butene dehydrogenation plants to obtain isobutene-free raffinates for prodn. of sec. butanol, MEK, butene-1, octenene or maleic anhydride. No previous extn. of butadiene from the 4C fraction is required. The isobutanol forms no azeotrope with the 4C hydocarbons (as occurs by use of methanol), so that sepn. of the ether by simple fractionation gives an almost alcohol-free 4C raffinate without water-washing, contg. 50 (20) esp. =5 ppm isobutanol. Isobutene is obtd. in high purity and yield. |