Reduced polymer formation for selective ethylene oligomerizations
AssigneeChevron Phillips Chemical Company LP
InventorsJared T. Fern, Orson L. Sydora, Uriah J. Kilgore, Steven M. Bischof, Eric R. Fernandez
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Abstract
Disclosed are processes, systems, and reaction systems for the oligomerization of ethylene to form an ethylene oligomer product in a reaction zone using a catalyst system comprising (a) a chromium component comprising an N2-phosphinyl amidine chromium compound complex, an N2-phosphinyl formamidine chromium compound complex, an N2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane. A C3+ olefin can be present in the reaction zone for a period of time, where the C3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.
Claims15
A process comprising:
- a) contacting i) ethylene, ii) a catalyst system comprising (a) a chromium component comprising an N2-phosphinyl amidine chromium compound complex, an N2-phosphinyl formamidine chromium compound complex, an N2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane, iii) an organic reaction medium, and iv) optionally hydrogen in a reaction zone;
- b) forming an ethylene oligomer product in the reaction zone;
- wherein ethylene, the catalyst system, and the organic reaction medium are introduced into the reaction zone, and for a C3+ olefin/ethylene feed period of time a C3+ olefin is introduced into the reaction zone,
- wherein over a reaction zone period of time the reaction zone has a C3+ olefin:ethylene weight ratio that decreases from a value of at least 0.5:1 to a value less than 0.2:1, wherein the C3+ olefin in the reaction zone that is used to determine the C3+ olefin:ethylene weight ratio in the reaction zone is not an ethylene oligomer formed in-situ within the reaction zone.
A process comprising:
- a) introducing into a reaction zone containing a C3+ olefin and optionally an organic reaction medium wherein the reaction zone is substantially devoid of ethylene;
- i) ethylene
- ii) a catalyst system comprising (a) a chromium component comprising an N2-phosphinyl amidine chromium compound complex, an N2-phosphinyl formamidine chromium compound complex, an N2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane,
- iii) the organic reaction medium, and
- iv) optionally hydrogen;
- and
- b) forming an ethylene oligomer product in the reaction zone;
- wherein over a period of time the reaction zone has a C3+ olefin:ethylene weight ratio which decreases from a value of at least 0.5:1 to a value less than 0.2:1, wherein the C3+ olefin in the reaction zone that is used to determine the C3+ olefin:ethylene weight ratio in the reaction zone is not an ethylene oligomer formed in-situ within the reaction zone.
Dependencies are inferred from the claim text.