This invention relates to a self cleaning reactor and to a process for the oligomerization of ethylene that employs a self-cleaning reactor. The reactor includes a mass of inert, particulate cleaning bodies that are entrained by the liquid in the reactor and scour the internal surfaces of the reactor during normal operation. This scouring action reduces the level of fouling on the reactor surfaces. Foulant material (polyethylene) is removed from the process on a continuous basis but the cleaning bodies remain within the reactor.

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feedstock of the following reactor n+1 in the cascade, a step of introducing said second part of the liquid phase withdrawn from the reactor n towards the reaction chamber of the following reactor n+1 in the direction of flow, a step of cooling said first part of the liquid fraction withdrawn from the reactor n in step c) by passing said first part of the liquid fraction into a heat exchanger in order to obtain a cooled liquid fraction, a step of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.

A process for the dehydrogenation of alkyl-containing compounds comprises reacting an alkyl-containing compound and a Group VI nitrosyl complex characterized as a transition metal complex having the composition Cp′M(NO)(R1)(R2), wherein Cp′ is selected from certain substituted and unsubstituted η.sup.5-cyclopentadienyl groups; M is W or Mo; and R1 and R2 are independently selected from CH.sub.2C(CH.sub.3).sub.3; CH.sub.2Si(CH.sub.3).sub.3; CH.sub.2(C.sub.6H.sub.5); CH.sub.3; hydrogen; and η.sup.3-allyl; provided that if R1 is hydrogen, R2 is η.sup.3-allyl; under conditions such that the alkyl-containing compound is converted to an olefin, and in particular embodiments, a terminal olefin. The dehydrogenation can be carried out using a neat and/or undried alkyl-containing compound and/or may be conducted under air, and does not require a sacrificial olefin to drive the reaction, thereby increasing convenience and decreasing cost in comparison with some other dehydrogenation processes.

Methods of preparing oligomers of an olefin are provided. The methods can include providing a composition that includes an alkylaluminum compound, a chromium compound, and a hydrocarbon solvent. The hydrocarbon solvent can include n-undecane, a C8-C11 alkane compound having one branch, or a mixture thereof. The methods can further include contacting an olefin with the composition to form oligomers of the olefin. The olefin can include ethylene, and the oligomers of the olefin can include 1-hexene.

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 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.

Catalyst compositions and processes for the oligomerization of ethylene to 1-hexene are described. The catalyst composition includes a triamino bisphospino (NPNPN) ligand system with specific phosphorous and nitrogen ligands. The terminal nitrogen atoms include linear alkyl hydrocarbons that differ in the number of carbon atoms by 3.

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.

Catalyst compositions and processes for the oligomerization of ethylene to 1-hexene are described. The catalyst composition includes a triamino bisphospino (NPNPN) ligand system with specific phosphorous and nitrogen ligands. The terminal nitrogen atoms include linear alkyl hydrocarbons that differ in the number of carbon atoms by 3.

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.