The invention relates to the field of oligomerization of olefins to produce linear α-olefins, in particular hexene-1, with the use of a catalyst system. The catalyst system comprises a chromium source compound, a nitrogen-containing ligand, alkylaluminum, and a zinc compound, wherein catalyst system is activated during its preparation by 1) heating some and SHF irradiation (microwave irradiation) of alkylaluminum or a mixture of the alkylaluminum and the zinc compound, or by 2) heating alkylaluminum or a mixture of the alkylaluminum and the zinc compound, followed by holding (aging) the prepared catalyst system for a certain period of time.

A method for preparing a homogenous catalyst for use in preparing a linear alpha olefin includes: preparing a first pre-catalyst solution by mixing a chromium source and a ligand in a first solvent, wherein the first pre-catalyst solution is stored in a first vessel; preparing a second pre-catalyst solution by mixing an organoaluminum compound and a modifier in a second solvent, wherein the second pre-catalyst solution is stored in a second vessel; and simultaneously feeding the first pre-catalyst solution and the second pre-catalyst solution directly into a reaction vessel, wherein the reaction vessel includes a third solvent.

According to one embodiment, a catalyst system that reduces polymeric fouling may include at least one chromium compound, at least one aluminum compound, and at least one antifouling agent or a derivative thereof. The antifouling agent may have a structure including a central aluminum molecule bound to an R1 group, bound to an R2 group, and bound to an R3 group. One or more of the chemical groups R1, R2, and R3 may be antifouling groups having the structure —O((CH.sub.2).sub.nO).sub.mR4, a phosphonium or phosphonium salt, a sulfonate or sulfonate salt, a sulfonium or sulfonium salt, an ester, an anhydride, a polyether, or a long-chained amine-capped compound, where n is an integer from 1 to 20, m is an integer from 1 to 100, and R4 is a hydrocarbyl group. The chemical groups R1, R2, or R3 that do not include an antifouling group, if any, may be hydrocarbyl groups.

The present disclosure relates to a process for stabilizing an antimony ammoxidation catalyst in an ammoxidation process. The process may comprise providing an antimony ammoxidation catalyst to a reactor; reacting propylene with ammonia and oxygen in the fluidized bed reactor in the presence of the antimony ammoxidation catalyst to form a crude acrylonitrile product; and adding an effective amount of an antimony-containing compound to the antimony ammoxidation catalyst to maintain catalyst conversion and selectivity; wherein the antimony-containing compound has a melting point less than 375° C. The present disclosure also relates to catalyst compositions and additional processes using the antimony ammoxidation catalyst stabilized by an antimony-containing compound.

The invention relates to a process for the oligomerization of ethylene, carried out at a pressure of between 0.1 and 10.0 MPa, at a temperature of between 30 and 200° C., in a cascade of N gas/liquid reactors in series, N being at least equal to 2, comprising a step of introducing a catalytic oligomerization system into at least the first reactor of the cascade, a step of bringing said catalytic system and an optional solvent into contact with ethylene by introducing said ethylene into the lower part of the reaction chamber of at least the first reactor of the cascade, for each reactor n, a step of withdrawing a liquid fraction in the lower part of the reaction chamber of the reactor n, the liquid fraction being separated into two streams: a first stream corresponding to a first, “main”, part of the liquid fraction, which is conveyed to a heat exchanger for cooling; a second stream corresponding to the second part of the liquid fraction which constitutes the liquid feedstock of the following reactor n+1 in the cascade, a step of introducing said second part of the liquid phase withdrawn from the reactor n towards the reaction chamber of the following reactor n+1 in the direction of flow, a step of cooling said first part of the liquid fraction withdrawn from the reactor n in step c) by passing said first part of the liquid fraction into a heat exchanger in order to obtain a cooled liquid fraction, a step of introducing said liquid fraction cooled in step e) at the top of the reaction chamber of said reactor n, the steps a) to f) being carried out, unless indicated otherwise, for each reactor n of the cascade, n being between 1 and N. The invention also relates to a device of N stirred gas/liquid reactors in a cascade, enabling the oligomerization process to be carried out.

Disclosed are a novel catalyst system which is a catalyst system for selectively oligomerizing olefin including ethylene and may trimerize and tetramerize olefin, different from the catalyst system for olefin oligomerization reported until now, and a method for preparing an olefin oligomer using same. The present invention provides a catalyst system for olefin oligomerization, including a ligand compound represented by Formula 1 or 2; a chromium compound; and a metal alkyl compound, and a method for preparing an olefin oligomer using same.

The present invention relates to a method of preparing -olefins by oligomerization of C.sub.2-C.sub.4 olefins. The method is carried out by oligomerization of C.sub.2-C.sub.4 olefins in the presence of a catalyst system comprising a transition metal source, an activator, which is an alkylaluminoxane, and a compound of formula (I), Ar.sup.1Ar.sup.2PN(R)PAr.sup.3Ar.sup.4 [formula I], wherein Ar.sup.1-4 are the same or different and are selected from substituted or unsubstituted C.sub.6-C.sub.10 aryl, R is selected from linear or branched C.sub.1-C.sub.4 alkyl, substituted or unsubstituted C.sub.6-C.sub.10 aryl, and substituted or unsubstituted C.sub.3-C.sub.10 cycloalkyl, wherein the oligomerization is carried out in a solvent, which is a bicyclic compound or a mixture of bicyclic compounds, preferably decalin. The claimed method provides a significant increase in the activity of the catalyst during the oligomerization process and, as a consequence, a reduction in the catalyst unit consumption, as well a reduction in the formation of polymer by-product.

A method for processing an oligomerization product stream includes discharging the oligomerization product stream from an oligomerization reactor through a product outlet line, and heating the oligomerization product stream, heating a wall of the product outlet line, or both. The oligomerization product stream includes solvent, linear alpha olefins, a polymer byproduct, or a combination of at least one of the foregoing. The heating is to a temperature that is greater than the melting temperature of the polymer byproduct present in the oligomerization product stream.

The present disclosure relates to a process for stabilizing an antimony ammoxidation catalyst in an ammoxidation process. The process may comprise providing an antimony ammoxidation catalyst to a reactor; reacting propylene with ammonia and oxygen in the fluidized bed reactor in the presence of the antimony ammoxidation catalyst to form a crude acrylonitrile product; and adding an effective amount of an antimony-containing compound to the antimony ammoxidation catalyst to maintain catalyst conversion and selectivity; wherein the antimony-containing compound has a melting point less than 375 C. The present disclosure also relates to catalyst compositions and additional processes using the antimony ammoxidation catalyst stabilized by an antimony-containing compound.

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.