Terminal to interior double bond isomerization process for an olefinic molecule with reduced dimerization
AssigneeShell Oil Company
InventorDavid M. Hamilton, Jr.
Life of this patent
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Abstract
The disclosure of the invention concerns a unique process for the isomerization of a double bond for movement of the same from the alpha position to an internal position of the olefinic molecule. The catalyst utilized for this migration is an 8 and 10 member ring aluminosilicate or tectosilicate having the surface treated with a silane compound.
Claims34
A double bond isomerization process for the movement of a double bond possessed by an alpha olefinic molecule from the alpha position to an interior position in said molecule, which process comprises contacting at least one of said olefin having an alpha double bond therein with a select aluminosilicate having 8 and 10 member ring channels of a size sufficient to permit said double bond isomerization and a size restrictive to prohibit aromatization or alkylation of said olefin molecule within said channels of said aluminosilicate, wherein said aluminosilicate is treated with a silylation agent prior to contact with said alpha olefin, at isomerization conditions, to thereby move said double bond from said alpha position to an interior position.
A process for the increased production of higher olefins having alpha double bonds from ethylene which comprises:
- (a) oligomerization of a feed material predominately comprising ethylene in an ethylene oligomerization zone, at oligomerization conditions, in the presence of an oligomerization catalyst, to form higher olefinic molecules having even carbon numbers of from C.sub.4 to C.sub.100 ;
- (b) separating said produced even numbered olefins in a first separation zone, at first separation zone conditions, to form a first olefin product stream having alpha double bonds and having from C.sub.12 to C.sub.18 and first separation zone effluent stream having:
- (1) unreacted ethylene, (2) light alpha olefins of from C.sub.4 to C.sub.10 and (3) heavy alpha olefins having from C.sub.20 to C.sub.100 ;
- (c) combining said light and said heavy 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 alpha olefins of step (d), at isomerization conditions, in the presence of a select aluminosilicate catalyst having 8 and 10 member ring channels of a size sufficient to permit said isomerization and a size restrictive to prohibit aromatization or alkylation of said olefin molecule within said channels of said aluminosilicate wherein said aluminosilicate is treated prior to isomerization of said alpha olefins with a silylation agent to modify the surface of the aluminosilicate and to thereby diminish the amount of dimerization during isomerization, wherein said isomerization produces 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 ;
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- (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 a light and heavy olefin fraction.
Dependencies are inferred from the claim text.