Disclosed are processes, systems, and reaction systems for the oligomerization of ethylene to form an oligomer product in a reaction zone using a catalyst system having i) a chromium component comprising an N.sup.2-phosphinyl amidine chromium compound complex, an N.sup.2-phosphinyl formamidine chromium compound complex, an N.sup.2-phosphinyl guanidine chromium compound complex, or any combination thereof, and ii) an aluminoxane. Ethylene can be contacted with an organic reaction medium to form an ethylene feedstock mixture prior to contact with the catalyst system. The ethylene feedstock mixture can be contacted with the catalyst system inside or outside of the reaction zone.

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 N.sup.2-phosphinyl amidine chromium compound complex, an N.sup.2-phosphinyl formamidine chromium compound complex, an N.sup.2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane. A C.sub.3+ olefin can be present in the reaction zone for a period of time, where the C.sub.3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.

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 N.sup.2-phosphinyl amidine chromium compound complex, an N.sup.2-phosphinyl formamidine chromium compound complex, an N.sup.2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane. A C.sub.3+ olefin can be present in the reaction zone for a period of time, where the C.sub.3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.

The present invention relates to chiral compounds with two optically active phosphorus atoms, chiral transition metal catalysts which comprise these compounds as ligands, a process for preparing the P-chiral compounds and processes for asymmetric synthesis using the chiral transition metal catalysts. The present invention specifically relates to a process for preparing an optically active carbonyl compound by asymmetric hydrogenation of a prochiral ,-unsaturated carbonyl compound with hydrogen in the presence of an optically active transition metal catalyst according to the invention. Yet more specifically, the present invention relates to a process for the asymmetric hydrogenation of citral, and also a process for preparing optically active menthol.

The present disclosure relates to a ligand compound, a catalyst system for oligomerization, and a method for olefin oligomerization using the same. The catalyst system for oligomerization using the ligand compound according to the present disclosure has excellent catalytic activity, exhibits high selectivity to 1-hexene and 1-octene, and greatly reduces the production of the by-products, thereby enabling efficient preparation of alpha-olefin.

The present disclosure relates to a ligand compound, a catalyst system for oligomerization, and a method for olefin oligomerization using the same. The catalyst system for oligomerization using the ligand compound according to the present disclosure has excellent catalytic activity, exhibits high selectivity to 1-hexene and 1-octene, and greatly reduces the production of the by-products, thereby enabling efficient preparation of alpha-olefin.

Vanadium phosphinic complex having general formula (I) or (II):

V(X).sub.3[P(R.sub.1).sub.n(R.sub.2).sub.3-n].sub.2(I)

V(X).sub.3[(R.sub.3).sub.2P(R.sub.4)P(R.sub.3).sub.2](II) wherein: X represents an anion selected from halogens such as, for example, chlorine, bromine, iodine, preferably chlorine; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; R.sub.1, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2CHCH.sub.2); or are selected from alkyl groups C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; n is an integer ranging from 0 to 3; R.sub.2, identical or different among them, are selected from optionally substituted aryl groups; R.sub.3, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2CHCH.sub.2); or are selected from alkyl groups C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.4 represents a group NR.sub.5 wherein R.sub.5 represents a hydrogen atom, or is selected from C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, linear or branched; or R.sub.4 represents an alkylene group (CH.sub.2) p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and R.sub.1 is methyl, R.sub.2 is different from phenyl.

Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

Vanadium phosphinic complex having general formula (I) or (II):

V(X).sub.3[P(R.sub.1).sub.n(R.sub.2).sub.3-n].sub.2(I)

V(X).sub.3[(R.sub.3).sub.2P(R.sub.4)P(R.sub.3).sub.2](II) wherein: X represents an anion selected from halogens such as, for example, chlorine, bromine, iodine, preferably chlorine; or is selected from the following groups: thiocyanate, isocyanate, sulfate, acid sulfate, phosphate, acid phosphate, carboxylate, dicarboxylate; R.sub.1, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2CHCH.sub.2); or are selected from alkyl groups C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups; n is an integer ranging from 0 to 3; R.sub.2, identical or different among them, are selected from optionally substituted aryl groups; R.sub.3, identical or different among them, represent a hydrogen atom, or an allyl group (CH.sub.2CHCH.sub.2); or are selected from alkyl groups C.sub.1-C.sub.20, preferably C.sub.1-C.sub.15, linear or branched, optionally halogenated, optionally substituted cycloalkyl groups, optionally substituted aryl groups; R.sub.4 represents a group NR.sub.5 wherein R.sub.5 represents a hydrogen atom, or is selected from C.sub.1-C.sub.20 alkyl groups, preferably C.sub.1-C.sub.15, linear or branched; or R.sub.4 represents an alkylene group (CH.sub.2) p- wherein p represents an integer ranging from 1 to 5; provided that in the general formula (I), in case n is equal to 1 and R.sub.1 is methyl, R.sub.2 is different from phenyl.

Said phosphinic vanadium complex having general formula (I) or (II) can be advantageously used in a catalytic system for the (co)polymerization of conjugated dienes.

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 N.sup.2-phosphinyl amidine chromium compound complex, an N.sup.2-phosphinyl formamidine chromium compound complex, an N.sup.2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane. A C.sub.3+ olefin can be present in the reaction zone for a period of time, where the C.sub.3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.

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 N.sup.2-phosphinyl amidine chromium compound complex, an N.sup.2-phosphinyl formamidine chromium compound complex, an N.sup.2-phosphinyl guanidine chromium compound complex, or any combination thereof, and (b) an aluminoxane. A C.sub.3+ olefin can be present in the reaction zone for a period of time, where the C.sub.3+ olefin is not an ethylene oligomer formed in-situ within the reaction zone.