The present invention relates to a method for olefin oligomerization and comprising i) injecting an olefin monomer and a solvent into a continuous stirred tank reactor (CSTR); ii) injecting an oligomerization catalyst system comprising a ligand compound, a transition metal compound, and a co-catalyst into the continuous stirred tank reactor; and iii) performing a multimerization reaction of the olefin monomer, wherein a ratio of the flowing rates of the olefin monomer and the solvent is from 1:1 to 2:1. In the method for olefin oligomerization according to the present invention, high linear alpha-olefin selectivity may be attained even with a small amount of a solvent used by controlling reaction conditions during the multimerization reaction of olefin by a continuous reaction using a continuous stirred tank reactor.

Provided in this disclosure are zirconium and hafnium complexes that contain 1) a cyclopentadienyl ligand; 2) an adamantyl-phosphinimine ligand; and 3) at least one other ligand. The use of such a complex, in combination with an activator, as an olefin polymerization catalyst is demonstrated. The catalysts are effective for the copolymerization of ethylene with an alpha olefin (such as 1-butene, 1-hexene, or 1-octene).

Ethylene oligomerization catalysts include a solid support having surface hydroxyl groups on a surface of the solid support. Functional groups attached to the solid support through at least one covalent bond and coordinated with at least one catalytically active transition metal. Individual functional groups are attached to the solid support as products of condensation reactions of at least one hydrolysable group of precursor ligands with a corresponding surface group of the solid support. The precursor ligands have a general formula (Ph.sub.2P).sub.2N—R.sup.1-A, where R.sup.1 is C.sub.1-C.sub.40 hydrocarbylene or C.sub.1-C.sub.40 heterohydrocarbylene; and A is a hydrolysable group selected from trialkoxysilyl, halosilyl, carboxylates, esters, phosphonates, amines, imines, thiols, thiocarboxylates, or halides.

Provided are a chromium catalyst precursor, an ethylene oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same. More particularly, a chromium catalyst precursor which may oligomerize ethylene with high activity and high selectivity in spite of not using methylaluminoxane (MAO) or modified-methylaluminoxane (MMAO), an oligomerization catalyst including the same, and a method of preparing an ethylene oligomer using the same are provided.

Catalyst systems suitable for tetramerizing ethylene to form 1-octene may include a catalyst comprising a chromium compound coordinated with a ligand and a co-catalyst comprising an organoaluminum compound. The ligand may include have a chemical structure according to formula (I), wherein at least one of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11, and R.sub.12 have the structure according to formula (II) wherein R.sub.A, R.sub.B, R.sub.C, and R.sub.D and the remainder of R.sub.1, R.sub.2, R.sub.3, R.sub.4, R.sub.5, R.sub.6, R.sub.7, R.sub.8, R.sub.9, R.sub.10, R.sub.11, and R.sub.12 are independently chosen from a hydrogen or a (C.sub.1-C.sub.50) hydrocarbyl group.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The invention relates to oligomerization of olefins, such as ethylene, to higher olefins, such as a mixture of 1-hexene and 1-octene, using a catalyst system that comprises a) a source of chromium b) one or more activators and c) a phosphacycle-containing ligating compound. Additionally, the invention relates to a phosphacycle-containing ligating compound and a process for making said compound.

The selective oligomerization of ethylene to produce a mixture comprising octene and hexene is conducted in the presence of a catalyst system comprising a source of chromium; two different P—N—P ligands and an activator. The phosphorus atoms of both ligands have ortho-fluoro phenyl substituents. The nitrogen atom of the first ligand has an isopropyl substituent. The nitrogen of the second ligand has a larger/bulkier hydrocarbyl substituent on the N atom. The hexene produced by the process of this invention has very high alpha selectivity.

The present invention relates to a ligand compound, a catalyst system for oligomerization of olefins including the ligand compound and the organic chromium compound, and a method for oligomerizing olefins using the same. The catalyst system for olefin oligomerization according to the present invention invention exhibits high selectivity to 1-hexene or 1-octene while having excellent catalytic activity, thereby enabling more efficient production of alpha-olefins.