Patent ID: 7485761

Claim:
A process for preparing 1-butene from 1-butane, which comprises: A) providing a n-butane-containing feed gas stream a; B) introducing the n-butane-containing feed gas stream a into at least one dehydrogenation zone and nonoxidative catalytic dehydrogenation of n-butane to give a product gas stream b comprising n-butane, 1-butene, 2-butene, butadiene, hydrogen, low-boiling secondary constituents and possibly water vapor; C) removing hydrogen, the low-boiling secondary constituents and, if appropriate, water vapor to give a C 4 product gas stream c consisting essentially of n-butane, 1-butene, 2-butene and butadiene; D) separating the C 4 product gas stream c into a recycle stream d1 consisting essentially of n-butane and a stream d2 comprising 1-butene, 2-butene and butadiene by extractive distillation, and recirculating the recycle stream d1 consisting essentially of n-butane to the dehydrogenation zone; E) introducing the stream d2 comprising 1-butene, 2-butene and butadiene into a selective hydrogenation zone, and selective hydrogenating butadiene to 1-butene and/or 2-butene to give a stream e comprising 1-butene and 2-butene; F) introducing the stream e comprising 1-butene and 2-butene and a circulating stream g comprising 1-butene and 2-butene into a distillation zone, and isolating a desired product stream f1 consisting essentially of 1-butene to leave a 2-butene-containing stream f2; and G) introducing the 2-butene-containing stream f2, if appropriate after a purge gas stream has been separated off, into an isomerization zone and isomerization of 2-butene to 1-butene so as to give a circulating stream g comprising 1-butene and 2-butene, and recirculating, if appropriate after a purge gas stream has been separated off from the circulating gas stream g, the circulating gas stream g to the distillation zone.