Terminal to interior double bond isomerization process for an olefinic molecule

In a process for the increased production of higher olefins having alpha double bonds from ethylene which comprises:

• (a) oligomerizing a feed material predominately comprising ethylene in an ethylene oligomerization zone, at oligomerization conditions in the presence of an oligomerization catalyst, to form higher linear olefinic molecules having even carbon numbers of from C.sub.4 to C.sub.100 ;
• (b) separating said produced even numbered linear olefins in a first linear separation zone, at first separation zone conditions, to form a first linear olefin product stream having alpha double bonds and having from C.sub.12 to C.sub.18 carbon numbers and first separation zone effluent streams having:
• (1) unreacted ethylene, (2) light linear alpha olefins of from C.sub.4 to C.sub.10 and (3) heavy linear alpha olefins having from C.sub.20 to C.sub.100 carbon atoms;
• (c) combining said light and said heavy linear alpha olefins and passing said combined stream to purification-isomerization-disproportionation steps and balancing therewith a quantity of C.sub.4 olefins to average the carbon number in said combined stream to approximately C.sub.12 ;
• (d) purifying said combined alpha olefin stream in the presence of a purification absorbent bed, at purification conditions, to remove from said combined stream impurities comprising oxygenates, metals, water and inorganics;
• (e) double bond isomerizing, in an isomerization step, said purified linear alpha olefins of step (d), at isomerization conditions, in the presence of an aluminosilicate catalyst and to produce an isomerization effluent stream having internal double bonds and being substantially free of alpha-situated double bonds;
• (f) disproportionating said isomerization olefin stream produced in step (e) in a disproportionation step in the presence of a disproportionation catalyst maintained at disproportionation conditions, to form an effluent stream containing C.sub.12 -C.sub.18 olefins and olefins lighter and heavier than C.sub.12 and C.sub.18 ;
• and
• (g) separating said disproportionation effluent stream of step (f) in a second separation zone maintained at second separation conditions to form a second olefin product stream having from C.sub.10 -C.sub.18 carbon atoms and to form a light and heavy olefin fraction, the improvement which comprises use as said catalyst of an aluminosilicate having 8 and 10 member ring channels having a size defined as being sufficient to permit said double bond isomerization of said olefin in said channels and a size restrictive to prohibit aromatization or alkylation of said olefin molecule within said channels.