Method for purifying isobutene from a c4 stream and process system therefor

A process for the purification of isobutene from a C4 stream which comprises at least 1-butene, 2-butene, isobutane and isobutene, comprising the following steps:

• supplying a stream of material which is concentrated in isobutane and isobutene obtained from the C4 stream and a stream of hydrogen to an isomerization reactor, wherein the isomerization reactor comprises a catalyst which comprises at least one metal which is active in hydrogenation on a first support;
• bringing the stream of material which is concentrated in isobutane and isobutene and the stream of hydrogen into contact with the catalyst in the isomerization reactor, whereupon 1-butene present in the stream of material which is concentrated in isobutane and isobutene is isomerized to 2-butene;
• supplying a product stream which comprises less 1-butene in relation to the stream of material which is concentrated in isobutane and isobutene from the isomerization reactor to a rectification column;
• and
• providing a stream of material which is concentrated in isobutene:
• by separating the stream of material which is concentrated in isobutane:
• via a side stream from the rectification column, or
• via a side stream and as a bottom product from the rectification column, or
• as the bottom product from the rectification column,
• wherein furthermore, a stream of material which is concentrated in isobutane is separated from the rectification column as an overhead product, or
• in which an overhead product from the rectification column that, is concentrated in isobutane, which contains isobutene in addition to the isobutane, is supplied to a second rectification column in order to separate the isobutane from the isobutene and to obtain the stream of material which is concentrated in isobutene in a bottom product from the second rectification column.