TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The facilitated transport membrane is promoted with Cu and/or Ag.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: In process (P1), the feed to the metathesis reactor is primarily 1-butene, and the second stream from the reactor contains ethylene and hexane. (P1) involves adding ethylene to the metathesis reactor, which reacts with 2-butene to form propylene; and further involves isomerizing the C4 feed stream in an isomerization reactor upstream from the metathesis reactor in order to increase the quantity of 1-butene in the C4 feed stream; and fractionating the isomerized C4 feed stream to form a 1-butene rich C4 feed stream and a 2-butene rich bottoms stream; which is then recycled to the isomerization reactor; and passing the 2-butene rich bottoms stream through a facilitated transport membrane to remove butanes. The product stream(s) of process (P1) include a hexene product stream, and (P1) further involves sending the hexene product stream to a hexene isomerization section to maximize 1-hexene production; fractionating the hexene stream to form a 1-hexene stream and a mixed 2- and 3-hexene stream; and recycling the 2- and 3-hexene stream to the hexene isomerization section. In process (P2), the first stream is a product stream, the first butene is 1-butene, and the second butene is 2-butene or isobutylene. The splitting in step (b2) takes place in a catalytic distillation column containing a selective hydrogenation catalyst in which a portion of the 1-butene is converted to 2-butene. The second butene is converted to the first butene in step (c2) by double bond isomerization or skeletal isomerization. The recycled portion of the second stream is passed through the facilitated transport membrane prior to isomerization. The C4 feed stream of process (P1) and (P2) contains poisons, and the method further involves removing poisons from the C4 feed stream before splitting. The isobutylene, acetylenics and/or dienes present in the C4 feed stream of process (P1) and (P2) is removed from the C4 feed stream before the splitting in step (b2). EXAMPLE - No relevant example given.