Process for preparing ethyl tert-butyl ether from technical mixtures of C4 hydrocarbons

摘要

Production of ethyl tertiary butylether (ETBE) from 4C-hydrocarbons mixture (I), comprises: (a) reaction of parts of the isobutene with ethanol in the presence of an acid catalyst to ETBE; (b) separation of the non-converted 4C-hydrocarbons (III) under receipt of a fraction (II) exhibiting ETBE; (c) distillative separation of the 4C-hydrocarbons (III) into a fraction (IV) and an isobutene-free fraction (V) containing at least 2-butene and n-butane; and (d) renewed reaction of the isobutene in fraction (IV) with ethanol (VI) to ETBE and separating non-converted 4C-hydrocarbon. Production of ethyl tertiary butylether (ETBE) from technical mixtures of 4C-hydrocarbons (I), which contain at least 1-butene, isobutene, n-butane and 2-butene, comprises: (a) reaction of parts of the isobutene with ethanol in the presence of an acid catalyst to ETBE; (b) separation of the non-converted 4C-hydrocarbons (III) from the discharge of the step (a) by thermal separation processes under receipt of a fraction (II) exhibiting ETBE; (c) distillative separation of the 4C-hydrocarbons (III) into a fraction (IV) containing at least 1-butene and isobutene and an almost isobutene-free fraction (V) containing at least 2-butene and n-butane; (d) renewed reaction of the isobutene contained in fraction (IV) with ethanol (VI) in the presence of an acid catalyst to ETBE; and (e) separation of the non-converted 4C-hydrocarbons (VIII) from the discharge of step (d) under receipt of a fraction (VII) exhibiting ETBE. An independent claim is included for a composition comprising larger than 90 mass proportions of ETBE, 0-5 mass proportions of ethanol, 0-2.5 mass proportions of tertiary butanol, =1.5 mass proportions of hydrocarbons with 5 or more carbon atoms and =1 mass proportion of 4C-hydrocarbons.