Method For Producing Propene From 2-Butene And Isobutene-Rich Feeding Flows

摘要

Process for preparing a stream consisting essentially of ethene (stream C₂⁼), a stream consisting essentially of propene (stream C₃⁼), a stream consisting essentially of isobutene and possibly other olefins having 4 carbon atoms (stream C₄⁼) and a stream consisting essentially of 2-methyl-2-butene and possibly 2-butene (stream C₅⁼), and, if appropriate, a stream which comprises other hydrocarbons (stream C_x) and may consist of a plurality of separate substreams, which comprises a metathesis step in which a C₄-hydrocarbon stream comprising at least 15% by weight of 2-butenes, at least 5% by weight of isobutene and not more than 5% by weight of 1-butene (feed stream) is brought into contact with ethene in the presence of a customary metathesis catalyst and the resulting hydrocarbon stream is fractionated to give the streams C₂⁼, C₃⁼, C₄⁼ and, if appropriate, C_x and all or part of the stream C₅⁼ is recirculated to the metathesis step.