摘要:
Ethylene is selectively oligomerized in a continuously stirred tank reactor (CSTR) that is preferably operated in an isothermal manner using a chromium catalyst. The undesired formation of by-product polyethylene is mitigated by contacting the ethylene with hydrogen prior to adding the ethylene to the reactor and feeding the ethylene and hydrogen via a common feed port.
摘要:
The oligomerization of ethylene using a chromium catalyst having a heteroatomic ligand may be used to provide oligomerization products that are selective towards hexene and/or octene. However, such processes also typically produce some polymer as an undesirable by product. The present invention is directed towards improvements in the selective oligomerization of ethylene.
摘要:
The oligomerization of ethylene using a chromium catalyst and an aluminoxane activator is well known. The undesired formation of polyethylene as a by-product is also known to occur during prior oligomerization processes. We have discovered that the use of an aluminoxane that is prepared by non-hydrolytic means provides a highly productive activator (co-catalyst) for ethylene oligomerization and mitigates the undesired formation of by-product polyethylene.
摘要:
The oligomerization of ethylene using a chromium catalyst having a bridged diphosphine ligand can produce a selective product distribution (to predominantly hexene or predominantly octene/hexene) when activated with an aluminoxane. The oligomerization reaction also produces polymer by product—particularly when the aluminoxane is provided in a non-aromatic solvent. The present invention mitigates this problem.
摘要:
This invention enables the “bulk” oligomerization of ethylene (i.e. the oligomerization of ethylene in the presence of the oligomer product) using a catalyst system comprising 1) a very low concentration of a chromium catalyst and 2) a three part activator. The chromium catalyst contains a diphosphine ligand, preferably a so called P—N—P ligand. The activator includes an aluminoxane, trimethyl aluminum, and triethyl aluminum.
摘要:
The oligomerization of ethylene using a chromium catalyst having a phosphorus-nitrogen-phosphorus (“P—N—P”) ligand is typically activated with an aluminoxane. The addition of an alkyl zinc, particularly diethyl zinc, has been fund to improve the productivity of certain oligomerization reactions. In particular, the addition of diethyl zinc to an oligomerization reaction that is activated by methylaluminoxane (MAO) improves the productivity of the reaction.
摘要:
Ethylene copolymers having a relatively high melt flow ratio and a multimodal profile in a temperature rising elution fractionation (TREF) plot are disclosed. The copolymers can be made into film having good dart impact values and good stiffness properties under decreased extruder pressures.
摘要:
A new P-N-P ligand in which each phosphorus atom is bonded to two ortho-fluorine substituted phenyl groups is useful in ethylene oligomerizations. In combination with i) a source of chromium and ii) an activator such as methalumoxane; the ligand of this invention may be used to prepare an oligomer product that contains a mixture of hexenes and octenes. The hexenes and octenes produced with this ligand contain very low levels of internal olefins when produced under preferred reaction conditions.
摘要:
A new P-N-P ligand in which each phosphorus atom is bonded to two ortho-fluorine substituted phenyl groups is useful in ethylene oligomerizations. In combination with i) a source of chromium and ii) an activator such as methalumoxane; the ligand of this invention may be used to prepare an oligomer product that contains a mixture of hexenes and octenes. The hexenes and octenes produced with this ligand contain very low levels of internal olefins when produced under preferred reaction conditions.
摘要:
A new P-N-P ligand in which each phosphorus atom is bonded to two ortho-fluorine substituted phenyl groups is useful in ethylene oligomerizations. In combination with i) a source of chromium and ii) an activator such as methalumoxane; the ligand of this invention may be used to prepare an oligomer product that contains a mixture of hexenes and octenes. The hexenes and octenes produced with this ligand contain very low levels of internal olefins when produced under preferred reaction conditions.