MXPA06009474A

MXPA06009474A - Methods of preparation of an olefin oligomerization catalyst

Info

Publication number: MXPA06009474A
Application number: MXPA/A/2006/009474A
Authority: MX
Inventors: J Baralt Eduardo; E Kreischer Bruce; D Knudsen Ronald; G Abbott Ronald; D Bridges Steven
Original assignee: G Abbott Ronald; J Baralt Eduardo; D Bridges Steven; Chevron Phillips Chemical Company Lp; D Knudsen Ronald; E Kreischer Bruce
Priority date: 2004-02-20
Filing date: 2006-08-18
Publication date: 2007-04-10

Abstract

A method of making a catalyst for use in oligomerizing an olefin comprising a chromium-containing compound, a pyrrole-containing compound, a metal alkyl, a halide-containing compound, and optionally a solvent, the method comprising contacting a composition comprising the chromium-containing compound and a composition comprising the metal alkyl, wherein the composition comprising the chromium-containing compound is added to the composition comprising the metal alkyl.

Description

METHODS FOR THE PREPARATION OF AN OLEFIN OLIGOMERIZATION CATALYST FIELD OF THE INVENTION The present invention relates to the preparation of catalysts for use in a process for producing an olefin oligomer. More particularly, the present invention relates to the preparation of trimerization catalysts comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, and a halide-containing compound, for use in a process for producing an oligomer of alpha-olefin comprising 1-hexene from ethylene.

BACKGROUND OF THE INVENTION Olefin oligomerization catalysts are known in the art, but sometimes, they lack selectivity to a desired product and also have a low product yield. Increases in preparation methods for oligomerization catalysts to improve productivity and selectivity to the desired product can reduce catalyst costs and improve economy.

SUMMARY OF THE INVENTION There is disclosed herein, a method for making a catalyst for use in the oligomerization of an olefin comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, the method comprises contacting a composition comprising the chromium-containing compound and a composition comprising the alkyl metal, wherein the composition comprising the chromium-containing compound is added to the composition comprising the alkyl metal. In addition, a method for making a catalyst for use in the oligomerization of an olefin comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent is described herein. , the method comprises reducing the precipitate by contacting a nitrogen-containing compound with an alkyl metal before contacting the alkyl metal with the chromium-containing compound, the pyrrole-containing compound, the non-metallic halide-containing compound, the solvent , or combinations thereof. In addition, a method for making a catalyst for use in the oligomerization of an olefin, comprising, contacting the Dimeric pyrrole compound with a chromium-containing compound, an alkyl metal, a halide-containing compound, a hydrocarbon solvent, or combinations thereof. In addition, a method for making a catalyst for use in the oligomerization of an olefin comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, and a halide-containing compound, comprising in contact with the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, or combinations thereof with a previously prepared oligomerization catalyst composition. In addition, a method for making a catalyst for use in the oligomerization of an olefin, comprising contacting a chromium-containing compound, a pyrrole-containing compound, and an alkyl metal, with an oligomerization catalyst composition is described herein. previously prepared. Furthermore, a method for olefin oligomerization comprising (a) preparing a catalyst by combining a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent is described herein.; and (b) contacting the catalyst with the olefin within about 1000 hours of the catalyst preparation. In addition, an ethylene trimerization catalyst comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound and optionally a solvent, wherein the 1-hexene produced by the catalyst has a purity of at least about 98.8 at a time within about 8000 hours after catalyst preparation.

BRIEF DESCRIPTION OF THE FIGURES Figures IA to ID illustrate various embodiments of a method for preparing an oligomerization catalyst comprising volume addition of catalyst components. Figures 2A through 2D illustrate various embodiments of a method for reducing water in the preparation of an oligomerization catalyst. Figures 3A to 3B illustrate various embodiments of a method for reducing water in the preparation of an oligomerization catalyst. Figures 4A through 4E illustrate various embodiments of a method for preparing an oligomerization catalyst comprising the simultaneous addition of catalyst components.

Figure 5 is a graph of the average residence time of the catalyst (ie, aging of the catalyst), against the purity of the hexene produced.

DETAILED DESCRIPTION OF THE INVENTION As used herein, a catalyst component includes a compound containing chromium, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, a solvent, or combinations thereof. In the various embodiments described in this document, the contact of catalyst components can occur in one or more contact zones. A contact zone is an area in which the components are mixed and / or combined, and thereby put in contact. The contact zone may be arranged in a container, for example, a storage tank, cargo, container, mixing vessel, reactor, etc .; a length of tube, for example, a tube in X? T ", inlet, injection port or manifold to combine component feed lines into a common line, or any other suitable device to put the components in contact. in this document, the terms put in contact and combined, refer to any sequence of addition, order, or concentration to put in contact or combine two or more catalyst components. The term "aggregate" refers to a first catalyst component added, for example, discharged, into a second catalyst component. Where a first catalyst component is added to a second catalyst component, the initial concentration or molar ratio of the first catalyst component, compared to the second catalyst component, is typically relatively minor and increases during the duration of the addition. In some embodiments, contact of the components may occur in one or more upstream contact area (s), before contacting in addition with another catalyst component (s) in one or more zone (s). ) contact downstream. Where a plurality of contact zones are employed, contact may occur simultaneously through the contact zones, sequentially through the contact zones, or both, as is suitable for a given mode. The contact can be carried out in a batch or continuous process, as is suitable for a given modality. In embodiments that use a container to contact the components, the components can optionally be mixed by a mixer, arranged in the container and the formed mixture can then be removed for subsequent processing. In modalities that use a "T" shaped tube or other means for combination lines such as manifolds, an optional line mixer, can be placed on the mixed catalyst feed line, to ensure proper contact of the combined components, and the mixture is formed in this way, as it passes through the mixing feed line, wherein a method for making a catalyst mentions the contact or combination of catalyst components, such can be carried out by contacting or by combining all or a portion of such components in various embodiments As used herein, a composition comprising a catalyst component includes the catalyst component alone or in combination with one or more additional compounds, solvents or both. None, some, or all of the contacting steps can be carried out in the presence of a solvent (sometimes referred to as an optional solvent), which can be introduced into a contact zone, via inclusion with one or more compositions that they comprise a catalyst component, or can be introduced separately into a contact zone, for example, in a solvent line or as an initial charge in a contact zone. It is described in this document, a method for making a catalyst comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, for use in the oligomerization of an olefin, wherein a composition comprising the compound contains chromium, is contacted in a contact zone with a composition comprising the alkyl metal. In Figure 1, four embodiments are illustrated for contacting the composition comprising the chromium-containing compound with the composition comprising the alkyl metal in the contact zone. Figures IA to ID are included as illustrative representations of modalities of the present description, and not limited thereto. In an embodiment as illustrated in Figure IA, the composition comprising the alkyl metal may be disposed in contact zone 115, and the composition comprising the chromium-containing compound may be contacted with, or added to, the composition. comprising the alkyl metal present in the contact zone 115 via line 110. The final catalyst composition can be recovered as a product via line 170. The composition comprising the chromium-containing compound in line 110, can further comprise the compound containing pyrrole, a compound containing halide not metallic, the solvent or combinations thereof. The composition comprising the chromium-containing compound may also comprise an amount of non-halide alkyl metal to reduce unwanted water, acidic protons or both, as described in more detail herein. The catalyst composition can further be diluted with a solvent (which may not be identical to the solvent in the catalyst preparation), before being used in the oligomerization reaction. The composition comprising the alkyl metal present in the contact zone 115, may comprise the pyrrole-containing compound, the halide-containing compound, the solvent, or combinations thereof. The halide-containing compound can be a metal halide, non-metallic halide, or combinations thereof. The composition comprising the alkyl metal may also comprise an alkyl metal halide, an alkyl non-halide metal, a non-metallic halide, a metal halide, or combinations thereof. The alkyl metal halide in this and other embodiments may comprise diethylammonium chloride (DEAC) and the non-halide alkyl metal may comprise triethylaluminum (TEA). In one embodiment, the alkyl metal may be the halide-containing compound, for example, DEAC is the halide-containing compound and the alkyl metal.

In a embodiment as illustrated in Figure IB, a pyrrole-chrome mixture can be formed in contact zone 225 by contacting a composition comprising the pyrrole-containing compound fed to contact zone 225 via the line 220 and the composition comprising the chromium-containing compound fed to the contact zone 225 via line 210, which may occur approximately instantaneously or for a first period of time from about 1 minute to about 12 hours, alternatively, from about 1 minute to about 6 hours, alternately, from about 1 minute to about 3 hours, alternately from about 1 hour to about 2 hours. The introduction of the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound to the contact zone 225 can be sequential (eg, chromium followed by pyrrole or vice versa) or simultaneously. Once the pyrrole-chromium mixture has been brought into contact in the contact zone 225, the pyrrole-chromium mixture of the contact zone 225 can be contacted or added to the composition comprising the alkyl metal present in contact zone 215 via line 240, which may occur approximately instantaneously or during a second period of time from about 1 minute to about 12 hours, alternately from about 1 minutes to about 6 hours, alternately from about 1 minute to about 3 hours, to form the final catalyst product in contact zone 215. The catalyst product Finally, it can be further diluted with a solvent (which may not be identical to the catalyst preparation solvent), before use in the oligomerization reaction. The composition comprising the pyrrole-containing compound in line 220 and the composition comprising the chromium-containing compound in line 210, can be contacted, for example, during the first period of time, at an approximately constant molar ratio from pyrrole to chromium (Py: Cr) or alternatively, at a variable molar ratio of Py: Cr to form the chromium-pyrrole mixture in the contact zone 225. The mixture of pyrrole-chromium in the contact zone 225, can then to be contacted or added to, for example, during the second period of time, the alkyl metal present in the contact zone 215 via line 240, or alternatively, already present in the contact zone 215, at a molar ratio approximately constant of Py: Cr, for example, in the range from about 1.0: 1 to approximately 4.0: 1. Alternatively, the pyrrole-chromium mixture in the contact zone 225 can then be brought into contact or added to, for example, during the second period of time, the alkyl metal present in the contact zone 215 via line 240 to a variable molar ratio of Py: Cr. In one embodiment, the variable molar ratio of Py: Cr is decreased during the second period of time, where a decreased molar ratio of Py: Cr refers to a general decrease trend in the molar ratio from the beginning of the sequence of addition to the term, and occasional increases in the ratio within the total decrease trend are acceptable. In a modality, a decreasing tendency of Py: Cr, refers to the specific situation where the term relation Py: Cr, is smaller than the relation of beginning of Py: Cr. In one embodiment, an initial molar ratio of Py: Cr at the beginning of the addition may be greater than the final molar ratio of Py: Cr of the catalyst; and a term molar ratio of Py: Cr at the end of the addition, may be less than the final molar ratio of Py: Cr of the catalyst. In one embodiment, the final molar ratio of Py: Cr of the catalyst may be in a range from about 1.0: 1 to about 4.0: 1; The initial molar ratio of Py: Cr may be greater than about 6: 1, alternatively, greater than about 20: 1, alternatively greater than about 40: 1, alternatively greater than about 60: 1, and the molar ratio of the term of Py: Cr can be greater than or equal to about 0, alternatively greater than or equal to about 0.1: 1, alternatively greater than or equal to about 0.3: 1, and alternatively greater than or equal to about 0.6: 1. In one embodiment, the initial molar ratio of Py: Cr is approximately twice the final molar ratio of Py: Cr of the catalyst during a first approximately half of the addition and the molar ratio of Py: Cr is approximately 0, during a second approximately half of the addition, wherein the final molar ratio of Py: Cr of the catalyst is in the range from about 1.0: 1 to about 4.0: 1. The introduction of a pyrrole-containing compound and a chromium-containing compound into a contact zone (e.g., formation of a mixture Py: Cr), as described in various embodiments, can be carried out as described in the paragraph , which includes but is not limited to the embodiments shown in Figures ID, 2C, 2D, 3B and 4A-E. The compositions comprising the chromium-containing compound in line 210 may comprise a non-metallic halide-containing compound, the solvent, or combinations thereof. The composition comprising the pyrrole-containing compound in line 220 may comprise a non-metallic halide-containing compound, the solvent or combinations thereof. The composition comprising the chromium-containing compound in line 210, the composition comprising the pyrrole-containing compound in line 220, or both, may also comprise an amount of non-halide alkyl metal to reduce unwanted water, acidic protons or both, as described in this document. Alternatively, the non-halide alkyl metal can be contacted with or added to the pyrrole-chromium mixture, for example, on line 240 via line 230, in contact zone 225 (not shown), or both, for reduce unwanted water, acidic protons or both. The compositions comprising the alkyl metal present in the contact zone 215 may comprise the halide-containing compound, the solvent or combinations thereof. The composition comprising the alkyl metal may also comprise an alkyl metal halide, a non-alkyl metal halide, a metal halide, non-metallic halide, or combinations thereof. In an embodiment as shown in Figure 1C, a pyrrole-alkyl metal mixture can be formed in the contact zone 325 by contacting the composition comprising the pyrrole-containing compound fed to the contact zone 325 via line 320 with the composition comprising the alkyl metal fed to contact zone 325 via line 315, which may occur approximately instantaneously or for a first period of time. The addition of the composition comprising the pyrrole-containing compound and the composition comprising the alkyl metal to the contact zone 325 can be sequential (eg, pyrrole followed by alkyl metal or vice versa) or simultaneously. Once the pyrrole-alkyl metal mixture has been contacted in the contact zone 325, the pyrrole-alkyl metal mixture of the contact zone 325 can be disposed via the line 360 in the contact zone 335. The composition comprising the chromium-containing compound may then be contacted with or added to the contact zone 335 via line 310, which may occur approximately or for a second period of time. The composition comprising the chromium-containing compound is thus contacted with or added to the pyrrole-alkyl metal mixture, present in the contact zone 335, to form the final catalyst product in the contact zone 335. The addition of the composition comprising the pyrrole-alkyl metal mixture and the composition comprising the chromium-containing compound to the contact zone 335, can be sequential (for example, pyrrole-alkyl metal followed by the compound containing chromium or vice versa), or simultaneously. The final catalyst product can be removed from the contact zone 335 via line 370. The final catalyst composition can also be diluted with a solvent (which may not be identical to the catalyst preparation solvent), before use in the Oligomerization reaction. Although the embodiment shown in Figure 1C shows two contact zones to be used to perform the addition sequences, the addition sequences could alternatively be performed in a single contact zone, for example, in contact zone 325. In this embodiment, the composition comprising the alkyl metal, can first be placed in the contact zone. In a second step, the composition comprising the pyrrole-containing compound can be contacted with, or added to, the composition comprising the alkyl metal present in the contact zone (or vice-versa), to properly contact and form the pyrrole-alkyl metal mixture. In a third step, the composition containing the chromium-containing compound can be contacted with or added to the pyrrole-alkyl metal mixture to form the final catalyst product. The composition comprising the chromium-containing compound in line 310, may comprise a non-metallic halide-containing compound, the solvent, or combinations thereof. The composition comprising the pyrrole-containing compound in line 320, may comprise a non-metallic halide-containing compound, the solvent, or combinations thereof. The composition comprising the chromium-containing compound in line 310, the composition comprising the pyrrole-containing compound in line 320, or both, may comprise an amount of non-halide alkyl metal to reduce undesirable water, acidic protons or both, . The composition comprising the alkyl metal in line 315, may comprise the halide-containing compound, the solvent, or combinations thereof. The composition comprising the alkyl metal may also comprise an alkyl metal halide, an alkyl non-halide metal, a metal halide, non-metallic halide, or combinations thereof. In an embodiment as shown in Figure ID, a composition comprising the pyrrole-containing compound on line 420, and a composition comprising the chromium-containing compound on line 410, can be simultaneously contacted with, or aggregates a, which can occur approximately instantaneously or over a period of time, with a composition comprising the alkyl metal present in the contact zone 415, and a final catalyst product can be removed from the contact zone 415 via line 470. The final catalyst composition can be further diluted with a solvent (which may not be identical to the catalyst preparation solvent), before being used in the oligomerization reaction. The composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound can be contacted with or added to the composition comprising the alkyl metal at molar ratios of Py: Cr previously described. The composition comprising the chromium-containing compound in line 410, may comprise a non-metallic halide-containing compound, the solvent, or combinations thereof. The composition comprising the pyrrole-containing compound in line 420 may comprise a non-metallic halide-containing compound, the solvent, or combinations thereof. In the embodiment shown in Figure ID, the composition comprising the alkyl metal in the contact zone 415, may comprise the halide-containing compound, the solvent or combinations thereof, each added to the contact zone 415 through of several input lines not shown in Figure ID. The composition comprising the alkyl metal may also comprise an alkyl metal halide, a non-halide alkyl metal, a halide metal, non-metallic halide, or combinations thereof. The composition comprising the chromium-containing compound in line 410, the composition comprising the pyrrole-containing compound in line 420, or both, may comprise an amount of non-halide alkyl metal to reduce unwanted water, acidic protons or both, . In addition, a method for making a catalyst comprising reducing all or a portion of water, acidic protons or both, from a composition comprising the chromium-containing compound, a composition comprising the compound containing pyrrole, a composition comprising the non-metallic halide-containing compound, a composition comprising the solvent, or combinations thereof before contact thereof with a composition comprising the metal-halide-containing compound. The reduction of water, acidic protons or both, may include neutralizing acidic protons; physically eliminate water; physically remove acidic protons; chemically bonding or reacting free water, so that the water is no longer free, or combinations thereof. The amount of water, acidic protons or both, removed from the catalyst component, can be determined using known methods, for example, by infrared analysis to determine the water content.

In embodiments for preparing a catalyst, one or more of the catalyst components may contain water, for example, the composition comprising the chromium-containing compound. The water may be present in a catalyst compound, for example, as a contaminant or as a co-product produced during the preparation of the catalyst compound. For example, water can be co-produced during the preparation of the chromium-containing compound, and such water can form complexes with chromium. Acidic protons may also be present, for example, the carboxylic acid (for example, ethylhexanoic acid), remains from the production of the chromium-containing product (for example tri (2-ethylhexanoate)). This free water, as well as the acid present in the chromium source, can subsequently react with a metal halide present in the catalyst, for example, the alkyl metal halide such as DEAC, to form corrosive compounds, for example, hydrogen halide (for example, hydrochloric acid). Such compounds can cause corrosion in downstream equipment over time, in particular when heated, for example, in downstream fractioning facilities. Accordingly, it may be desirable to reduce water, acidic protons or both, when the catalysts are made to prevent downstream formation of potentially corrosive derivatives. In addition, in embodiments of a method for preparing a catalyst, impurities in the catalyst components can participate in unwanted side reactions that lead to the formation of precipitates. These precipitates can lead to additional undesired reactions, for example, polymer formation in the trimerization of ethylene to 1-hexene. The water can be an initiator of the precipitation reactions and therefore, it can be desirably reduced from the catalyst components to improve the selectivity to 1-hexene. The reduction of water, acidic protons or both, can also have a beneficial impact on the efficiency of the catalyst, even where the corrosive compounds are produced. For example, in one embodiment, water is reduced from one or more catalyst components by contacting them with a reduced corrosive compound such as a halide-containing compound, which reacts with, and reduces water. Reactions of water with a corrosive reduction compound such as a halide-containing compound can produce a corrosive compound, for example, HCl, and as such should be taken into account in the overall design of the system. Examples of suitable halide-containing compounds for reaction with water include a metal halide, a halide of metal alkyl, a non-halide alkyl metal and a metal halide, a non-metallic halide, or combinations thereof. The use of a halide-containing compound for reducing water may be used in place of or in addition to other water-reducing embodiments described herein, such as the use of a non-halide alkyl metal to reduce water. In one embodiment, water, acidic protons or both, can be reduced by pre-contacting, one or more catalyst components with a non-corrosive reduction component, which is a compound that does not form a corrosive compound, such as a halide compound of hydrogen after contact with water, acidic protons or both. Non-corrosive reduction compounds include, for example, a non-halide alkyl metal such as TEA. Corrosive reduction compounds are compounds that can form a corrosive compound after contact with water, acidic protons or both, such as (i) alkyl metal halide, (ii) a metal halide and an alkyl metal, and (iii) a non-metallic halide and an alkyl metal. Corrosive reduction compounds also include any other combination of compounds that form a corrosive compound after contact with water, acidic proton, or both. In one modality, one or more components catalysts such as a composition comprising the chromium-containing compound, a composition comprising the pyrrole-containing compound, a non-metallic halide-containing compound, a solvent, or combinations thereof, are contacted with a non-halide alkyl metal to reduce water, acidic protons or both,. The non-halide alkyl metal can react with free water, acidic protons or both, contained in the catalyst component (s), when they are previously contacted to reduce water, acidic protons or both. The non-halide alkyl metal can be pre-mixed in a contact zone with one or more catalyst components. The pre-mix can be made by either adding the non-halide alkyl metal to the catalyst component (s) or vice versa, and in one embodiment, the pre-mix can be made by adding the non-halide alkyl metal to the ( the) catalyst component (s). These additions can be made in various relationships as described above. In one embodiment, the non-halide alkyl metal added in, is contacted with a composition comprising the chromium-containing compound. Since chromium can react with the non-halide alkyl metal to form a gel, it may be desirable to maintain a low concentration of non-halide alkyl metal by adding in the composition comprising the chromium-containing compound, so that there may be only an amount available to react with water and acid. Conversely, with a high concentration of non-halide alkyl metal, such as may occur when the composition comprising the chromium-containing compound is added to the non-halide alkyl metal, more non-halide alkyl metal could be available to react with the chromium (and with it, form a gel), after the water and acid are removed. In each embodiment, the water or acid reducing substance (eg, a non-halide alkyl metal) can be contacted with or added to one or more catalyst components in an effective amount to substantially reduce all free / available water , acidic protons or both, of some or all of the components put in contact with the non-halide alkyl metal. In one embodiment, the amount of non-halide alkyl metal contacted with, or added to, such components is less in relation to the amount of the catalyst components which is being contacted with or added to them. In one embodiment, the portion of the non-halide alkyl metal contacted with or added to a catalyst component (s) may be less than or equal to about 30 weight percent of the component (s). s) catalyst (s) to which they are put in contact or added to these; alternatively less than about 20 weight percent of the catalyst component (s) to which they are contacted or added thereto; alternatively, less than about 10 weight percent of the catalyst component (s) to which they are contacted or added thereto; alternatively less than about 5 weight percent of the catalyst component (s) to which they are contacted or added thereto. In one embodiment, the portion of the non-halide alkyl metal contacted with or added to a catalyst component (s) may be less than or equal to about 120 mole percent of the catalyst component (s) (s). ) to which you contact or are added to it; alternatively, less than about 80 mole percent of the catalyst component (s) to which it is contacted or added thereto; alternatively less than about 40 mole percent of the catalyst component (s) to which it is contacted or added thereto; alternatively less than about 20 mole percent of the catalyzed component (s) to which it is contacted or added thereto. The non-halide alkyl metal can be contacted with or added to a catalyst component (s) in an amount such that the molar ratio of the non-halide alkyl metal to the catalyst component (s), may be less than about 1.5: 1, alternatively less than about 1.2: 1, alternatively less than about 1: 1. The non-halide alkyl metal can be contacted with or added to a catalyst component (s) in a sufficient molar ratio to reduce at least about 25% water, acidic protons or both, associated with the component (s) catalysts present in the contact prior to the contact zone; alternatively, at least about 90% water, acidic protons or both, associated with the catalyst component (s) present in the contact prior to the contact zone; alternatively at least about 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the contact prior to the contact zone; alternatively in an amount which may be at least about 10% in excess of an amount sufficient to reduce at least about 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the the contact prior to the contact area; alternatively, in an amount that can be at least about 20% in excess of an amount sufficient to reduce at least, approximately 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the contact prior to the contact zone; alternatively, in an amount which may be at least about 30% in excess of an amount sufficient to reduce at least about 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the contact prior to the contact area; alternatively, it may be at least about 100% in excess of an amount sufficient to reduce at least about 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the prior contact the contact area; or alternatively in an amount which may be at least about 200% in excess of an amount sufficient to reduce at least about 100% of the water, acidic protons or both, associated with the catalyst component (s) present in the the contact prior to the contact area. After the reduction of water, acidic protons or both, from one or more catalyst components, such reduced catalyst components, can be stored until they are needed for the preparation of a catalyst composition. Such storage may or may not be in the presence of a solvent. The pre-mix comprises a portion of a non-halide alkyl metal, and one or more reduced catalyst component (s) can be contacted with the remaining catalyst components including the alkyl metal halide, to form the catalyst product final. The remaining catalyst components may also comprise additional non-halide alkyl metal to comprise the non-halide alkyl metal composition in the final catalyst. In one embodiment, the additional non-halide alkyl metal may be the same as that used in the pre-mix. Alternatively, the additional non-halide alkyl metal may be different from that used in the premix. Figures 2A-2D represent various embodiments for reducing water, acidic protons or both, in the composition comprising the chromium-containing compound, the composition comprising the pyrrole-containing compound, or both, before contact with the composition comprising a compound that contains metal halide. Figures 2A to 2D are included as illustrative representations of modalities of the present description and do not limit thereto. In addition, several modalities to reduce water, acidic protons or both, can be combined to increase the total effectiveness. The composition comprising a compound that containing chromium, it can be contacted with the non-halide alkyl metal to form a premix prior to contacting the mixture with the remaining catalyst components. In a modality shown in Figure 2A, a composition comprising the chromium-containing compound, can be disposed in the contact zone 510, the placement of which can take place via the entry line 505. The composition in the zone of contact 510 may optionally contain solvent, other catalyst components, or combinations thereof, provided that the contact zone 510 does not comprise (i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal. A non-halide alkyl metal, optionally in a solvent, can be added to the composition containing a chromium-containing compound in the contact zone 510 via line 530. The non-halide alkyl metal can be added in an amount less than or equal to to about 30 weight percent of the composition containing the chromium-containing compound, to which it is added or in other amounts as described herein. The resulting mixture in the contact zone 510 can then be passed from the contact zone 510 via the line 511 and optionally fed in a filter 512, comprising dry filter medium (free of some water), to filter any precipitate that may have formed from the mixture. The precipitate can be filtered and the filtrate can be passed via line 513 in contact zone 515 for contact with the remaining catalyst components which include a composition comprising the alkyl metal, the pyrrole-containing compound, the halide-containing compound (for example, a metal halide, or non-metallic halide), the solvent, any remaining non-halide alkyl metal, alkyl metal halide, or combinations thereof, which may be placed in the contact zone 515 via several lines of input not shown in Figure 2A. A catalyst product can then be removed from the contact zone 515 via line 570. Where the filtration is omitted, the remaining catalyst components can be alternately contacted, in the contact zone 510. The composition comprising a compound that it contains pyrrole, it can be contacted with the non-halide alkyl metal to form a mixture, before contacting the mixture with the remaining catalyst components. In a embodiment shown in Figure 2B, a composition comprising a pyrrole-containing compound can be disposed in the contact zone 620 via the entry line 607. The composition in the contact zone 620 it may optionally contain solvent, other catalyst components, or combinations thereof, provided that the contact zone 620 does not comprise (i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal. Metal non-halide alkyl, which may be in solvent, may be added to the composition containing a pyrrole-containing compound in the contact zone 620 via line 630. The non-halide alkyl metal may be added in a lesser amount than or equal to about 10 weight percent of the composition containing the pyrrole-containing compound to which it is added or in other amounts as described herein. The resulting mixture in contact zone 620 may then be passed from contact zone 620 via line 621 and optionally filtered (not shown), to remove any precipitate that may have formed in the mixture. The resulting mixture can then be fed into the contact zone 615 to contact the remaining catalyst components which include a composition comprising the alkyl metal, the chromium-containing compound, the halide-containing compound (eg, a halide metal). or non-metallic halide), the solvent, any remaining non-halide alkyl metal, alkyl metal halide, or combinations thereof, the which can be placed in the contact zone 615 via several input lines not shown in Figure 2B. A catalyst product can then be removed from the contact zone 615 via line 670. Where the filtration is omitted, the remaining catalyst components can alternatively be brought into contact in the contact zone 620 via several input lines not shown in the Figure 2B. The composition comprising the chromium-containing compound can be contacted with the composition comprising the pyrrole-containing compound to form a mixture before contacting the mixture with the non-halide alkyl metal. In an embodiment as illustrated in Figure 2C, a pyrrole-chrome mixture can be formed in the contact zone 724, by contacting a composition comprising the pyrrole-containing compound, fed to the contact zone 725 via the line 720 and the composition comprising the chromium-containing compound fed to the contact zone 725 via line 710, which may occur approximately instantaneously or for a first period of time. The feed of the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound to the contact zone 725 can be sequential (for example, chromium followed by pyrrole). or vice versa), or ltaneously, to constant or variant relations of Py: Cr as previously described. Once the pyrrole-chromium mixture has been brought into contact in the contact zone 725, the pyrrole-chromium mixture of the contact zone 725 can be placed in the contact zone 731 via line 740. The mixture of pyrrole-chromium may optionally contain solvent, other catalyst components, or combinations thereof, but does not comprise (i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a halide non-metallic and an alkyl metal. The non-halide alkyl metal, which may be in a solvent, may be added to the pyrrole-chromium mixture in the contact zone 731 via line 730. The non-halide alkyl metal may be added in an amount less than or equal to a, about 10 weight percent of the pyrrole-chromium mixture, to which it is added or in other amounts as described herein. Although not shown in Figure 2C, the contact area 725 and the contact area 731 may be the same contact area, provided that the addition sequence as described above remains the same. The resulting mixture in the contact zone 731 can then be passed out of the contact zone 731 via line 732 and optionally filtered (not shown), to remove any precipitate that may have formed in mix. The mixture can be fed into the contact zone 715 to contact the remaining catalyst components which include a composition comprising the alkyl metal, the halide-containing compound (eg, a metal halide or non-metallic halide), the solvent, any remaining non-halide alkyl metal, alkyl metal halide, or combinations thereof, which may be placed in the contact zone 715 via several input lines not shown in Figure 2C. A catalyst product can then be removed from the contact zone 715, via line 770 and can optionally be filtered on a filter (not shown). Where the filtration is omitted, the remaining catalyst components may alternatively be contacted in the contact zone 725 or 731. The composition comprising a chromium-containing compound may be contacted with a non-halide alkyl metal to form a first mix; The composition comprising a pyrrole-containing compound can be contacted with the non-halide alkyl metal to form a second mixture, and the first and second mixtures can be contacted with the remaining catalyst components. In a modality shown in Figure 2D, a composition containing a chromium-containing compound can be disposed in the contact zone 810, the placement of which takes place via the input lines 805. The composition in the contact zone 810 may optionally contain solvent, other catalyst components, or combinations thereof, but the contact zone 810 does not comprise (i ) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (ii) a metal halide and an alkyl metal. The non-halide alkyl metal, which may be in a solvent, may be added to the composition containing a chromium-containing compound in the contact zone 810 via line 830, forming a first mixture. The non-halide alkyl metal may be added in an amount of less than or equal to about 10 weight percent of the composition containing the chromium-containing compound, to which it is added or in other amounts as described herein. A second mixture can be formed in the contact zone 820. The composition comprising a pyrrole-containing compound can be disposed in the contact zone 820, the placement of which takes place via the line of entry 807. The composition that comprises a pyrrole-containing compound in the contact zone 820, may optionally contain a solvent, other catalyst components, or combinations thereof, but does not comprise (i) an alkyl metal halide, (ii) a metal and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal. The non-halide alkyl metal, which may be in a solvent, may be added to the composition containing a pyrrole-containing compound in the contact zone 820 via line 831, forming the second mixture. The non-halide alkyl metal may be added in an amount less than or equal to about 10 weight percent of the composition containing the pyrrole-containing compound to which it is added or in other amounts as described herein. The first mixture, second mixture or both, which can optionally be filtered (not shown), to remove any precipitate that may have formed in the mixtures. Optionally, they can be stored either the first, second or both mixtures. The first and second blends can then be fed into the contact zone 815 via lines 811 and 821, respectively, to contact the remaining catalyst components which include the composition comprising the metal halide. Alternatively, although not shown in Figure 2D, the first and second mixes can be contacted separately in another contact area prior to being fed via a mix feed line into the contact zone 815, and such a feed line mixed can be optionally filtered to remove any precipitate that may have formed. The contact zone 815 may initially be comprised of a composition comprising the alkyl metal, a halide-containing compound (e.g., a halide metal, or non-metallic halide), a solvent, the remaining non-halide alkyl metal, metal halide alkyl, or combinations thereof, all of which have been placed in contact zone 815 via several input lines not shown in Figure 2D. A catalyst product can then be removed from the contact zone 815 via line 870 and optionally filtered (filter not shown). In alternative embodiments, the remaining catalyst components can be contacted in the contact zone 810 or 820. The addition of the composition comprising the pyrrole-containing compound and the composition comprising the chromium-containing compound as shown in the Figures 2C and 2D, can be elaborated in constant ratios or variants of Py: Cr as previously described. Water can be removed from the chromium-containing compound before contact with the metal-halide-containing compound, in accordance with various water-reduction modalities described herein. In one embodiment, the catalyst feed pile that contains chromium, can be contacted with an azeotropic solvent such as an aromatic compound, paraffin solvent, chlorinated solvent, another solvent, or mixture of solvents capable of forming an azeotrope with water. The azeotropic solvent, the chromium-containing compound, and any water present, form a solution and the solution may be subjected to an azeotropic distillation to remove the water, where the solvent-water azeotrope is a low-boiling component. Optionally, the solvent used to remove water by azeotropic distillation can be recovered after azeotropic distillation. In one embodiment, the azeotropic solvent used to remove water using azeotropic distillation, may comprise ethylbenzene, benzene, meta-xylene, ortho-xylene, para-xylene, mixed xylenes, toluene, octane, nonane, heptane, hexane, mixed hexanes, cyclohexane , carbon tetrachloride, chloroform, dichloromethane, 1,1,2-trichloroethane or combinations thereof. The amount of water removed from a catalyst component by various reduction methods can be monitored using known analytical methods such as infrared analysis. In a modality shown in Figure 3A, a composition containing a chromium-containing compound, can be disposed in the contact zone 910, the placement of which takes place via an entry line. 905. The composition in the contact zone 910 may optionally contain solvent, other catalyst components, or combinations thereof, but the contact zone 910 does not comprise (i) an alkyl metal halide, (ii) a metal halide and a metal alkyl, or (iii) a non-metallic halide and an alkyl metal. An azeotropic solvent, for example, a composition comprising an aromatic compound, such as ethylbenzene, can be added to the composition containing a chromium-containing compound in contact zone 910, via line 902 or directly added to a separate 900 The azeotropic solvent can be added in an effective amount to form an azeotropic solution with the chromium-containing compound. In one embodiment, the azeotropic solvent can be added in an amount from about 0.5 to about 1000 times the weight of the composition containing the chromium-containing compound to which it is added, alternatively from about 0.5 to about 500 times the weight, alternatively from about 0.5 to about 100 times the weight, alternately from about 0.5 to about 50 times the weight, alternately from about 0.5 to about 25 times the weight, alternately from about 0.5 to about 15 times the weight.

The resulting azeotropic solution in the contact zone 910 can then be passed from the contact zone 910 via line 911 and fed in a separator 900 for the azeotropic distillation of the solution to remove the water. The operating temperature of the separator 900 will depend on the azeotropic solvent used and the pressure maintained in the separator. Water can be removed from separator 900 through airline 912, optionally the recovered compound, and the remaining reduced components, can be fed via line 913 into contact zone 915 to contact the remaining catalyst components include the composition comprising the alkyl metal, the pyrrole-containing compound, the halide-containing compound (e.g., a metal halide or non-metallic halide), the catalyst solvent, any remaining non-halide alkyl metal, alkyl metal halide, or combinations thereof, which can be placed in the contact zone 915 via several input lines not shown in Figure 3A. A catalyst product can then be removed from the contact zone 915 via line 970 and optionally filtered (not shown). Alternatively, the reduced water material comprising the chromium-containing compound can be stored prior to contact with the remaining catalyst components. Optionally, Reduced components of line 913 can be subjected to further water reduction as described herein, for example, by contact with a non-halide alkyl metal, adsorbent or both, prior to contact with the remaining catalyst components. In one embodiment, one or more catalyst components other than (i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal, for example, the composition comprising the chromium-containing compound, the composition comprising the pyrrole-containing compound, the compound containing non-metallic halide, the solvent, or combinations thereof, are contacted with an adsorbent to reduce water. The contact may occur before contacting (i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal. In some embodiments, contacting the chromium-containing compound with the pyrrole-containing compound can improve the solubility of the chromium-containing compound in a solvent (eg, ethylbenzene), as well as reducing the viscosity of the solution. In this way, the reduced viscosity and the more soluble solution can improve the suitability of the solution to the reduction of water by passing it through an adsorbent such like molecular sieves, to remove all or a portion of some water present. In one embodiment, the added pyrrole may constitute substantially all or only a portion of the pyrrole required to make the catalyst composition. Other known means for reducing viscosity, improving solubility, or both, may be employed, such that a catalyst component becomes suitable for contact with an adsorbent to remove water. Adsorption as used herein, refers to the separation operation in which, a gas component or liquid mixture is selectively retained in the pores of a microcrystalline or resinous solid. A liquid or gas mixture contacts a solid (the adsorbent) and a mixing component (the adsorbate, which is typically water), adheres to the surface of the solid. In one embodiment, an adsorbent can be used to reduce water, by adding the adsorbent to the catalyst component (s) in a container, and mixing it vigorously for suitable contact of the adsorbent with the catalyst component (s) (is) . The mixture can then be allowed to stand and after a period of time, the adsorbent settles to the bottom of the container. The separation can be completed by decanting or filtration (eg filtration through suction). Alternatively, the water can be reduced by passing the catalyst component (s) through a fixed adsorption bed comprised of an adsorbent, allowing the mixture the appropriate contact time for the adsorbate to adhere sufficiently to the adsorbent. adsorbent, and then remove the reduced catalyst component (s) from the adsorption bed. The adsorbent can then be replaced or regenerated for later use. The original adsorption capacity of the saturated bed can be recovered by any suitable method of regeneration, for example, thermal regeneration, regeneration by pressure oscillation or purging regeneration. In the embodiments, any suitable adsorbent can be used. Examples of suitable adsorbents include 3-Angstrom molecular sieves, 5-Angstrom molecular sieves, 13X molecular sieves, alumina, silica, or combinations thereof. 3-Angstrom (3A) and 5-Angstrom (5A), refers to the size of the molecule that the material can adsorb, for example, the 3A molecular sieve, can adsorb molecules of less than 3 angstroms and the molecular sieve of 5A , it can adsorb molecules of less than 5 angstroms. Molecular sieves are crystalline structures not unlike sponges on a molecular scale. They have a solid structure that defines large internal cavities, where the molecules can be adsorbed. These cavities are interconnected by pore openings through which molecules can pass. Due to its crystalline nature, pores and cavities are the same size, and depending on the size of the apertures, molecules can be adsorbed quickly, slowly or not all, thus, functioning as molecular sieves - adsorbing molecules of certain sizes while they reject the biggest ones. In an embodiment as illustrated in Figure 3B, the pyrrole-chromium mixture can be formed in the contact zone 1025 by contacting a composition comprising the pyrrole-containing compound fed to the contact zone 1025 via the line 1020 and the composition comprising the chromium-containing compound fed to the contact zone 1025 via line 1010, which may occur approximately instantaneously or for a first period of time. The feed of the chromium-containing composition and the pyrrole-containing composition to the contact zone 1025 can be sequential (for example, chromium followed by pyrrole or vice versa), or simultaneously and to constant ratios or variants of Py: Cr as described previously. Once the pyrrole-chromium mixture has been brought into contact in the contact zone 1025, the pyrrole-chrome mixture in the zone of contact 1025, may be passed to contact zone 1000 via line 1040. The pyrrole-chromium mixture may optionally contain solvent, other catalyst components, for example, a non-metallic halide, or combinations thereof, but do not comprise ( i) an alkyl metal halide, (ii) a metal halide and an alkyl metal, or (iii) a non-metallic halide and an alkyl metal. The pyrrole chromium mixture is brought into contact with an adsorbent disposed in the contact zone 1000. The contact zone 1000 can be a fixed adsorption bed as described in a previous embodiment, classified in accordance with the volumes of the materials be adsorbed. The pyrrole-chromium mixture can be passed through the adsorption bed comprised of an adsorbent, for example, 3A molecular sieve, allowed for the adsorption process to occur during a second period of time to adsorb essentially all the free water of the pyrrole-chromium mixture. The contact with the adsorbent in the contact zone 1000 can be carried out according to various known methods. The reduced mixture of water in the contact zone 1000 can then be passed from the contact zone 1000 via the line 1018 and brought into contact with the remaining catalyst components in the contact zone 1015 which includes the composition comprising the metal alkyl, a halide-containing compound (eg, a metal halide or non-metallic halide), the solvent, any remaining non-halide alkyl metal, alkyl metal halide, or combinations thereof, which may be placed in the contact zone 1015 via several input lines not shown in Figure 3B. A catalyst product can then be removed from the contact zone 1015 via line 1070 and optionally filtered (not shown). Alternatively, the reduced water material comprising the chromium-containing compound can be stored prior to contact with the remaining catalyst components. Optionally, the reduced water components of the contact zone 1000 may be subjected to further water reduction as described herein, for example, by contact with a non-halide alkyl metal, azeotropic distillation, or both, prior to contacting. with the remaining catalyst components. Modalities for reducing water, acidic protons or both, as described herein, for example, in the embodiments shown in Figures 2A-2D and 3A-3D, can be applied alone or in combination with other known catalyst processes and compositions in The technique, for example, water, acidic protons or both, can be reduced from the catalyst compositions or components described in the reference documents of U.S. Patent No. 6,133,495, U.S. Application No. 2002/0035029, WO 01/83447, WO 03/053890 and WO 03/053891, each of which is incorporated herein in its entirety. Similarly, embodiments for preparing catalysts, for example, modalities shown in Figures 1A-1D and 4A-4E, can be applied alone or in combination with other catalyst processes and compositions known in the art, for example, those set forth in 6,133,495, 2002/0035029, WO 01/83447, WO 03/053890 and WO 03/053891. When the methods of catalyst preparation and water reduction are applied to these catalyst compositions or components, described in reference documents US Pat. No. 6,133,495, Sol. U.S. No. 2002/0035029, WO 01/83447, WO 03/053890 and WO 03/053891, appropriate substitutions and adjustments should be made, for the components having a similar function; for example, replacement of multidentate ligands of WO 03/053890 and WO 03/053891 for the pyrrole compound used herein, and adjustments of the molar ratios of the ligand: Cr (pyrrole: chromium) are counted for the number of equivalents of ligand (s) per mole of the ligand. In addition, the catalyst compositions or components described in the reference documents U.S. Pat. No. 6,133,495, Sol. U.S. N. 2002/0035029, WO 01/83447, WO 03/053890 and WO 03/053891, may be combined with other catalyst compositions or components as set forth herein, to make various final catalysts in accordance with various embodiments described herein, and water may be reduced from any one or more of such compositions or components by any one or more reduction methods described herein. In one embodiment, water, acidic protons or both, can be reduced from the catalyst composition to produce an alpha-olefin oligomer described in US Pat. No. 6,133,495. A chromium-based catalyst is prepared, carrying a pyrrole ring-containing compound, an aluminum alkyl compound, and a halogen-containing compound, in contact with each other in a hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof, and then bringing the resulting mixed solution into contact with the chromium compound, wherein water, acidic protons or both, are reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, the chromium-based catalyst is prepared by carrying the chromium compound, the pyrrole ring-containing compound, the alkyl aluminum compound, and the halogen-containing compound, in contact with each other in a hydrocarbon solvent, a solvent of halogenated hydrocarbon or mixture thereof, in the absence of an alpha-olefin under such conditions, such that the concentration of the chromium compound in the resulting mixed solution is approximately lxlO-7 to 1 mol / liter, alternatively, approximately 1-xlO-5. up to 3 × 10 -2 mol / liter, alternatively adjusted to no more than about 8 × 10-3 mol / liter, alternatively, no more than about 0.416 mg Cr / ml, wherein water, acidic protons or both, are reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, water, acidic protons or both, are reduced from a catalyst component comprising a pyrrole derivative represented by the general formula (I): wherein R1 to R4 are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms, in which R3 and R4 can integrally form a ring; X is a halogen atom; M is an element selected from the group consisting of those belonging to Group 3, Group 4, Group 6 (exclusive of chrome), Group 13, Group 14 and Group 15 of the Periodic Table; m and n are numbers that satisfy the relationships of 1 <; m < 6, 0 < n < 5 and 2 < m + n = 6, with the proviso that the sum of m and n is identical to the valence of the element M; n represents the number of Rs; and R is a hydrogen atom or a straight or branched hydrocarbon group having 1 to 20 carbon atoms and when n is not less than 2, and Rs may be the same or different. In one embodiment, water, acidic protons or both, can be reduced from the catalyst composition described in US Patent No. 2002/0035029. In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A can be a ligand neutral multidentate having a tripoid structure, M can be a transition metal atom of group 3 to group 10 of the periodic table, each Q can be independently selected from the group consisting of a hydrogen atom, a halogen atom , a straight or branched chain alkyl group having from 1 to 10 carbon atoms, which may have a substituent, an aryl group which has 6 to 10 carbon atoms, which may have a substituent, and n is an integer equal to a formal oxidation valence of M, and (ii) an alkylaluminioxane; said neutralized multidentate ligand A in formula (1) is a tridentate ligand represented by the following formula (2) or of formula (3): (2) where j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L1 are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group which has 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) Da2-L2 where a, b and c independently represent an integer from 0 to -6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A is a multidentate ligand neutral that has a tripoid structure, M is a transition metal atom of group 3 to group 10 of the periodic table, each Q is independently selected from the group consisting of a hydrogen atom, a halogen atom, a chain alkyl group linear or branched having 1 to 10 carbon atoms, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent, and n is an integer equal to an oxidation valence formal of M, and (ii) an alkylaluminioxane, and (iii) a halogenated organic compound; said neutralized multidentate ligand A in the formula (1) is a tridentate ligand represented by the following formula (2) or formula (3): (2) where j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the provided that the three L1s are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) D2-L2 wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst.

In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A is a multidentate ligand neutral having a tripoid structure, M is a transition metal atom of group 3 to group 10 of the periodic table, each Q is independently selected from the group consisting of a hydrogen atom, a halogen atom, an alkyl group straight or branched chain having 1 to 10 carbon atoms, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent, and n is an integer equal to a valence of formal oxidation M, (ii) an alkylaluminioxane, (iii) a halogenated organic compound, and (iv) a compound containing an alkyl group, represented by the following formula (4): RpEJq (4) wherein p and q are numbers satisfying the formulas : 0 < p = 3 and 0 = q < 3, provided that (P + q) is in the range of 1 to 3, E represents an atom, other than a hydrogen atom of group 1, 2, 3, 11, 12 or 13 of the periodic table, each R independently represents an alkyl group having 1 to 10 carbon atoms, and each J independently represents a hydrogen atom, a group alkoxide having 1 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or a halogen atom; said neutralized multidentate ligand A in the formula (1), is a tridentate ligand represented by the following formula (2) or formula (3): (2) D! -L1 where j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L1 are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group which has 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) Da2-L2 wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A is a neutral multidentate ligand having a tripoid structure, M is a transition metal atom of group 3 to group 10 of the periodic table, each Q is independently selected from the group consisting of one atom of hydrogen, a halogen atom, a straight or branched chain alkyl group having from 1 to 10 carbon atoms, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent, and n is an integer equal to a valence of formal oxidation of M, (ii) an alkylaluminioxane, and (iii) a compound containing an alkyl group, represented by the following formula (4): RpEJq (4) wherein p and q are numbers satisfying the formulas: 0 <p = 3 and 0 = q < 3, provided that (P + q) is in the range of 1 to 3, E represents an atom, other than a hydrogen atom of group 1, 2, 3, 11, 12 or 13 of the periodic table, each R represents independently an alkyl group having 1 to 10 carbon atoms, and each J independently represents a hydrogen atom, an alkoxide group having 1 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or a halogen atom; said neutralized multidentate ligand A in the formula (1), is a tridentate ligand represented by the following formula (2) or formula (3): (2) Di wherein j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently representing a substituent which contains an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L1 are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group which has 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or an atom of • phosphorus when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A is a multidentate ligand neutral having a tripoid structure, M is a transition metal atom of group 3 to group 10 of the periodic table, each Q is independently selected from the group consisting of a hydrogen atom, an atom of halogen, a straight or branched chain alkyl group having from 1 to 10 carbon atoms, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent, and n is a number integer equal to a formal oxidation valence of M, (ii) an alkylaluminioxane, and (iii) at least one compound selected from the group consisting of an amine compound and an amide compound; said neutralized multidentate ligand A in the formula (1), is a tridentate ligand represented by the following formula (2) or formula (3): (2) where j, ky, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L's are not concurrently a substituent that contains an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, a catalyst for ethylene trimerization comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A is a neutral multidentate ligand having a tripoid structure, M is an atom of transition metal from group 3 to group 10 of the periodic table, each Q is independently selected from the group consisting of a hydrogen atom, a halogen atom, a straight or branched chain alkyl group having from 1 to 10 atoms carbon, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent, and n is an integer equal to a formal oxidation valence of M, (ii) an alkylaluminioxane, (iii) at least one compound selected from the group consisting of an amine compound and an amide compound, and (iv) a compound containing an alkyl group represented by the following formula (4): RpEJq (4) wherein p and q are numbers that satisfy the formulas: 0 < p = 3 and 0 = q < 3, provided that (P + q) is in the range of 1 to 3, E represents an atom, other than a hydrogen atom of group 1, 2, 3, 11, 12 or 13 of the periodic table, each R independently represents an alkyl group having 1 to 10 carbon atoms, and each J independently represents a hydrogen atom, a group alkoxide having 1 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or a halogen atom; said neutralized multidentate ligand A in the formula (1), is a tridentate ligand represented by the following formula (2) or formula (3): (2) D, -1 where j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L1 are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group which has 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen atom or phosphorus, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst. In one embodiment, an olefin oligomerization catalyst system, which incorporates a halogen source in a pyrrole ligand as described in WO 01/83447, and water, acidic protons or both, can be reduced from the catalyst system or a component of it, before or during the preparation of the catalyst. In one embodiment, water, acidic protons or both, are reduced from a catalyst component comprising a pyrrole ligand. The catalyst system can comprise a source of chromium, an alkyl metal, and the ligand halopyrrole can be used to produce 1-hexene by trimerization of ethylene. In one embodiment, an olefin oligomerization catalyst system, incorporating a heteroatom ligand blended with at least three heteroatoms, of which at least one heteroatom is sulfur and at least 2 heteroatoms, is not the same, as dibed in WO 03/053890, and water, acidic protons or both, can be reduced from the catalyst system or a component * thereof, before or during the preparation of the catalyst. In one embodiment, water, acidic protons or both, are reduced from the catalyst system or a catalyst component comprising a multidentate heteroatomic mixed ligand, which includes at least three heteroatoms of which at least one is a sulfur atom. The catalyst system can comprise a source of chromium, an alkyl metal, an aluminaxane and the mixed heteroatomic ligand multidentate, and can be used to produce 1-hexene by trimerization of ethylene.

In one embodiment, water, acidic protons or both, can be reduced from the ligand and the ligand can be comprised of the following types of ligands: (a) RXA (R2BR3) (R4CR5) wherein R1, R3 and R5 can be hydrogen or independently be selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R4 may be the same or different and are hydrocarbyls of Ci up to about C5; A is nitrogen or phosphorus; and B and C are sulfur; and (b) RaA (R2BR3R4) (R5CR5) wherein R1, R31, R4 and R6 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl , carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R5 may be the same or different and are hydrocarbyls of Ci up to about C5; A and B are individually nitrogen or phosphorus; and C is sulfur; and (c) AÍR ^ R ^ 3) (R4CR5) wherein R2, R3 and R5 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R1 and R4 may be the same or different and are hydrocarbyls of Ci up to about C5; B is nitrogen or phosphorus; and A and C are sulfur; and (d) AÍR ^ R ^ 3) (R4CR5R6) wherein R2, R3, R5 and R6 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy , aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R1 and R4 may be the same or different and are hydrocarbyls of Ci up to about C5; B and C are individually nitrogen or phosphorus; and A is sulfur. In one embodiment, the ligand may comprise bis (2-ethylsulfanyl-ethyl) -amine, bis- (2-methylsulfanyl-ethyl) -amine, bis- (2-butylsulfanyl-ethyl) -amine, bis- (2-decylsulfanyl- ethyl) -amine, bis- (2-butylsulfanyl-ethyl) -amine, bis- (2-decylsulfanyl-ethyl) -amine, bis- (ethylsulfanylmethyl) -amine, bis- (2-ethyl-sulphanyl-phenyl) -amine, bis - (2-ethylsulfanyl-ethyl) phosphine, bis- (2-ethylsulfanylethyl) -ethylphosphine, bis- (2-ethylsulfanylethyl) -phenylphosphine, N-methylbis- (2-ethylsulfanyl-ethyl) -amine, (2-ethylsulfanyl-ethyl) (3-ethylsulfanyl-propyl) -amine, (2-ethylsulfanyl-ethyl) (2-diethylphosphino-ethyl) -amine, (2-ethylsulfanyl-ethyl) (2- diethylphosphinoethyl) -sulfide, (2-ethylsulfanyl-ethyl) (2-diethylethoxyethyl) -amine and (ethylsulfanyl-ethyl) (2-diethylamino-ethyl) -sulfide, (2-ethylsulfanyl-ethyl) (2-diethylphosphino- ethyl) -phosphine, (2-ethylsulfanyl-ethyl) (2-diethylaminoethyl) -ethylphosphine, bis- (2-diethylphosphino-ethyl) -sulfide, bis- (2-diethylamino-ethyl) -sulfide, (2-diethylphosphino-ethyl) ) (2-diethylamino-ethyl) sulfide and derivatives thereof, wherein water, acidic protons or both, can be reduced from the ligand. In one embodiment, an olefin oligomerization catalyst system incorporates a heteroatom ligand blended with at least three heteroatoms, of which at least one hetero atom is nitrogen and at least two heteroatoms are not the same, as described in WO 03 / 053891, and water, acidic protons or both, can be reduced from the catalyst system or a component thereof before or during catalyst preparation. In one embodiment, the ligand may be a mixed multidentate heteroatomic ligand for an olefin catalyst oligomerization, said ligand includes at least three heteroatoms. At least one heteroatom can be nitrogen and at least two heteroatoms can not be the same. The ligand may contain, in addition to nitrogen, at least one phosphorus heteroatom. In one embodiment, the ligand can be selected in such a way as none of the non-carbon-based heteroatoms are directly linked by any of the other non-carbon-based heteroatoms. In one embodiment, the ligand can not include a sulfur hetero atom. In one embodiment, water, acidic protons or both, can be reduced from a ligand having the structure R ^ A ^ BR ^ 4) (R5CR6R7) where R1, R3, R4, R6 and R7 can be hydrogen or independently selected of the group consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R5 are the same or different and are hydrocarbyls of Ci up to about C5; and at least A, B or C is nitrogen with the remainder of A, B and C being individually nitrogen or phosphorus. In one embodiment, the ligand may comprise bis- (2-diethylphosphino-ethyl) -amine, bis- (diethylphosphino-methyl) -amine, bis- (2-diethylphosphino-phenyl) -amine, N-methylbis- (2-diethylphosphine) -ethyl) -amine, bis- (2-diphenylphosphino-ethyl) -amine, (2-diethylphosphino-ethyl) (3-diethylphosphino-propyl) -amine, bis- (2-dicyclohexylphosphino-ethyl) -amine, N-benzylbis - (2-Diethylphosphino-ethyl) -amine, N-methyl- (2-diethylphosphino-ethyl) (3-diethylphosphino-propyl) -amine, (2-diethylphosphinoethyl) (2-diethylamino-ethyl) -amine, N-methyl - (2-diethylphosphino-ethyl) (2-diethylamino-ethyl) -amine and bis- (2-diethylamino-ethyl) -ethylphosphine. A suitable mixed multidentate heteroatomic ligand is bis- (2-diethylphosphino-ethyl) -amine and derivatives thereof, wherein water, acidic protons or both, can be reduced from the ligand. In one embodiment, a nitrogen-containing compound can be contacted with the alkyl metal, before contacting the alkyl metal with the chromium-containing compound, the pyrrole-containing compound, the halide-containing compound, the solvent or combinations thereof, to make a catalyst for use in oligomerization of an olefin. Typically, the catalyst preparation can result in undesirable reaction products of alkyl metal, for example aluminum alkyls, with water impurities. The water present in the catalyst components over time, which is added to the alkyl metal compound can be a source of precipitates that can lead to polymer formation in the oligomerization reaction. Such precipitates can be reduced by the addition of an alkyl metal nitrogen compound, thereby improving the solubility of the undesired reaction products and preventing precipitation, and further minimizing the production of the polymer in the oligomerization reaction. The nitrogen compound can be comprised of amines, pyrroles, pyridines, substituted pyrroles such as Índoles, di and tri-heterocycles of nitrogens, or combinations thereof. In one embodiment, the nitrogen compound can be 2, 5-dimethylpyrrole, which in this case, the nitrogen compound can serve two different functions: one, in the formation of the active site in the catalyst system; and two, in preventing precipitation of the product of the water and alkyl metal reaction (as an improved solubility). In one embodiment, the nitrogen-containing compound is tributyl amine. In one embodiment, the final catalyst product is comprised of from about 0.01 to about 10 moles of nitrogen per mole of metal; alternatively the final catalyst product is comprised of from about 0.05 to about 5 moles of nitrogen per metal mold; or alternatively the final catalyst product is comprised of from about 0.1 to about 0.5 moles of nitrogen to mol of metal. In an embodiment for making a catalyst comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent for use in oligomerization of an olefin, the chromium-containing compound, the compound containing pyrrole and the alkyl metal They can be simultaneously contacted. In one embodiment, the simultaneous contact of the catalyst components occurs via the addition of a single contact zone. Simultaneous contact may occur for a period of time from about 1 minute to about 12 hours; alternatively from about 1 minute to about 6 hours; or alternatively from about 1 minute to about 3 hours. In one embodiment, the simultaneous 0 contact may occur for a period of less than or equal to about 120 minutes to form a catalyst product. In one embodiment, one or more of the catalyst components may be fed to the contact zone at mass flow rates of about 5 0.1 Kg / hr to about 500 Kg / hr, alternatively from about 5 Kg / hr to about 250 Kg. / hr; alternatively from about 10 Kg / hr to about 150 Kg / hr; alternatively from about 0.1 Kg / hr to about 100 Kg / hr; 0 alternatively from approximately 0.1 Kg / hr to 50 Kg / hr; alternatively from approximately 0.5 Kg / hr to 25 Kg / hr; or alternatively from approximately 1.0 Kg / hr to 10 Kg / hr. Such mass flow rates can also be employed with other embodiments described in this document. In one modality, the simultaneous contact is performed in a continuous process (where the period of time can be a prolonged period of time), or alternatively in a batch process. In one embodiment, the alkyl metal can be a solution comprising a non-metallic halide and an alkyl metal, an alkyl metal halide, a metal halide and an alkyl metal, or combinations thereof. In one embodiment, the halide-containing compound can also be simultaneously contacted with the chromium-containing compound, the pyrrole-containing compound and the alkyl metal, for example, by simultaneous addition to the hydrocarbon solvent. In an embodiment as shown in Fig. 4A, the composition comprising the chromium-containing compound can be fed into the contact zone 1100 via line 1110, the composition comprising the pyrrole-containing compound can be fed into the zone of contact 110 via line 1120, the composition comprising the alkyl metal can be fed into the contact zone 1100 via line 1115, and the composition comprising the halide-containing compound can be fed into the contact zone 1100 via line 1180, all the compositions are fed into the contact zone 1100 simultaneously for a period of time. In an embodiment as shown in Fig. 4B, the composition comprises the Chromium-containing compound, can be fed into the contact zone 1100 via line 1110, the composition comprising the pyrrole-containing compound can be fed into the contact zone 1100 via line 1120, the compositions comprising the alkyl metal and the compound containing halide, can be previously contacted and fed into the contact zone 1100 via line 117, the final compositions are fed into the contact zone 1100 simultaneously for a period of time. In an embodiment as shown in Fig. 4C, the compositions comprising the chromium-containing compound and the pyrrole-containing compound can be pre-contacted and fed into the contact zone 1100 via line 1122, the composition comprising the alkyl metal can be fed into the contact zone 1100 via line 1115, and the compositions comprising the halide-containing compound can be fed into the contact zone 1100 via line 1180, the final compositions are fed into the contact zone 1100 simultaneously during a period of time. In an embodiment as shown in Fig. 4D, the compositions comprising the chromium-containing compound and the pyrrole-containing compound can be pre-contacted and fed into the contact zone 1100 via line 1122 and the compositions comprising the metal alkyl and the Halide-containing compound, can be previously contacted and fed into the contact zone 1100 via line 1117, the final compositions are fed into the contact zone 1100 simultaneously over a period of time. In the embodiments shown in Figs. 4A-4D, a hydrocarbon solvent can be placed in the contact zone 1100 before, after or at the same time with the addition of various catalyst components. The contact area 1100 can comprise a simple container, for example a storage tank, box, container, mixing container, etc. A product of the catalyst can be separated from the contact zone 1100 via line 1170 and optionally filtered (filter not shown). In the embodiments shown in Figs. 4A-4D, the addition of the composition comprising the pyrrole-containing compound and the composition comprising the chromium-containing compound, can be made in constant ratios or variants of Py: Cr, as previously described. Additionally, embodiments for reducing water, acidic protons or both, shown in Figs. 2A-2D and 3A-3B, can be combined with the simultaneous addition modalities of Figs. 4A-4D. In an embodiment for making a catalyst comprising a compound containing chromium, a compound containing pyrrole, an alkyl metal, a compound which contains halide and optionally a solvent for use in or oligomerization of an olefin, compositions comprising the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, optionally the halide-containing compound or combinations thereof, may be in contact with a previously prepared oligomerization catalyst composition. The previously prepared oligomerization catalyst solution may comprise the same or different chromium-containing compound, pyrrole-containing compound, alkyl metal and halide-containing compound. The halide-containing compound may comprise a metal halide, an alkyl metal halide or combinations thereof. Any of the embodiments described herein can be carried out to make catalysts, wherein the new catalyst can be prepared in one or more contact zones comprising the existence of the previously prepared active catalyst. For example, in the embodiments shown in Figs. 4A-D, contact zone 1100, can be a holding tank for the active catalyst to be fed to an oligomerization reactor and be comprised of the previously prepared oligomerization catalyst. The various catalyst compounds in lines 1110, 1115, 1117, 1120, 1122 and 1180 can be combined simultaneously with the composition of the oligomerization catalyst previously prepared in the contact zone 1100. In an embodiment as shown in Fig. 4E, the contact zone can be a holding tank for the active catalyst to be fed to a reactor. oligomerization and comprise the oligomerization catalyst previously prepared. The chromium-containing compound in line 1210 may be combined with a hydrocarbon solvent in line 1250 forming a first solution in contact zone 1225. The pyrrole-containing compound in line 1220, the alkyl metal in line 1215 and the optional halide containing compound on line 1280 can be combined with the hydrocarbon solvent on line 1251 formed a second solution in contact zone 1235. The hydrocarbon solvent on line 1250 can be the same or different solvent of hydrocarbon at line 1251. The first solution in contact zone 1225 and the second solution in contact zone 1235 can then be contacted (eg, simultaneously or sequentially, including a plurality of repetitive addition sequences) with the composition of the oligomerization catalyst previously prepared in the contact zone 1200 via lines 1216 and 1218, respectively, to make r the new composition of the catalyst. Optionally, a mixer can be arranged in the contact zone 1200 until completely mixing the new and the existing components of the catalyst. Again, the contact of the composition comprises the pyrrole-containing compound and the composition comprising the chromium-containing compound can be made at constant ratios or variants of Py: Cr, as previously described. Additionally, the modes for reducing water, acidic protons or both, shown in Figs. 2A-2D and 3A-3B, can be combined with the simultaneous addition mode of Fig. 4E. The contacting of the catalyst components can be done under sufficient conditions until the components are completely contacted. Typically, the contacting is carried out in an inert atmosphere, such as, for example, nitrogen and / or argon. The reaction temperature for the described methods of making a catalyst for use in olefin oligomerization can be any temperature. To facilitate the operation, the room temperature can be used. To effect a more efficient reaction, temperatures which keep the reaction mixture in a liquid state are desirable. In one embodiment, the reaction temperature is maintained at least about 120 ° C; alternatively less than approximately 100 ° C; alternatively less than about 75 ° C; alternatively less than about 50 ° C; or alternatively less than 25 ° C when the compositions comprising the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, the halide-containing compound or combinations thereof are contacted to make the catalyst. The preparation of the catalyst system at a low temperature can increase the activity of the catalyst and reduce levels of the polymer of undesirable co-products. The reaction pressure for the methods described to make a catalyst for use in oligomerization of an olefin can be any pressure which does not adversely affect the reaction. Generally, pressures within the range of about atmospheric pressure to about three atmospheres are acceptable. Atmospheric pressure can be used to facilitate the operation. The reaction time for the methods described for making a catalyst for use in the oligomerization of an olefin, can be any amount of time that can substantially react all the reactants (ie, catalyst components). Depending on the reagents, as well as the temperature and reaction pressure, the reaction time may vary. Usually, the times less than about 1 day may be sufficient, for example from about 1 minute to about 12 hours. In one embodiment, the reaction times are from about 1 minute to about 6 hours, alternately from about 1 minute to about 3 hours. Longer times usually do not provide additional benefits and shorter times may not allow enough time to complete the reaction. The resulting olefin oligomerization catalyst system prepared as described above in any of the embodiments, can be collected and recovered under an inert, dry atmosphere, to maintain stability and chemical reactivity. In one embodiment, it may be desired to contact the catalyst with the olefin within about 1000 hours of catalyst preparation; alternatively the catalyst may be in contact with the olefin within about 800 hours of catalyst preparation; alternatively, the catalyst may be in contact with the olefin within about 600 hours of catalyst preparation; alternatively the catalyst may be in contact with the olefin within about 400 hours of catalyst preparation; or alternatively the catalyst can be in contact with the olefin within about 200 hours of the catalyst preparation. In one embodiment, the olefin oligomerization catalyst comprising the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, the halide-containing compound and optionally the solvent, can product to product (eg, hexane) have a purity of minus 99.4 at a time within approximately 200 hours after catalyst preparation; alternatively the product may have a purity of at least about 99.3 at a time within about 400 hours after catalyst preparation; alternatively the product may have a purity of at least about 99.1 at a time within about 600 hours after the preparation of the catalyst; alternatively the product may have a purity of at least about 98.8 at a time within about 800 hours after the preparation of the catalyst; or alternatively the product may have a purity of less than about 98.8 at a time greater than about 900 hours after the preparation of the catalyst. The chromium-containing compound can be one or more chromium compounds, organic or inorganic, with a chromium oxidation state of from about 0 to about 6. As used in this description, You can include the chromium metal in this definition of a chromium compound. Generally, the chromium-containing compound will have a CrXn formula, wherein X may be the same or different and may be any organic or inorganic radical, and n may be an integer from 0 to 6. Suitable organic radicals may have about 1 to about 20 carbon atoms per radical, and selected from alkyl, alkoxy, ester, ketone, amino radicals or combinations thereof. The organic radicals can be cyclic or acyclic with straight or branched chain, aromatic or aliphatic; and can be made from mixed, aromatic and / or cycloaliphatic aliphatic groups. Suitable inorganic radicals include, but are not limited to halides, sulfates, oxides or combinations thereof. The compound having chromium can be a compound of chromium (II), composed of chromium (III) or combinations thereof. Suitable chromium (III) compounds include, but are not limited to, chromium carboxylates, chromium naphthenates, chromium halides, chromium pyrrolides, chromium benzoate, chromium dionates or combinations thereof. Specific chromium (II) compounds include, but are not limited to, chromium (III) isooctanoate, chromium (III) 2,2,6,6-tetramethylheptanedithion, chromium (III) naphthenate, chromium (III) chloride , tris (2- ethylhexanoate) of chromium (III), chromic bromide, chromic chloride, chromic fluoride, chromium oxy-2-ethylhexanoate (III), chromium (III) dichloroethylhexanoate, chromium (III) acetylacetonate, chromium (III) acetate, chromium (III) butyrate, chromium (III) neopentanoate, chromium laurate (III), chromium (III) stearate, chromium (III) oxalate, chromium (III) benzoate, chromium (III) pyrrolide (s) or combinations thereof. Suitable chromium (II) compounds include, but are not limited to, chromium fluoride, chromium chloride, chromium bromide, chromium iodide, chromium (II) bis (2-ethylhexanoate), chromium (II) acetate, chromium (II) butyrate, chromium (II) neopentanoate, chromium (II) laurate, chromium (II) stearate, chromium (II) oxalate, chromium (II) benzoate, chromium pyrrolide (s) (II) ) or combinations thereof. In one embodiment, the chromium-containing compound can be chromium (III) 2-ethylhexanoate. In one embodiment, the content of monomeric chromium and the residual radicals (excess) are optimized. This value is designated by the mole ratios of Cr: ((moles of ligand x number of coordination equivalents of ligand / mole of ligand) / oxidation number of Cr). In one embodiment, the mole ratio of Cr: ((moles of ligand x number of ligand coordination equivalents / mole of ligand) / Cr oxidation number) is approximately 0. 9: 1 to about 1.1: 1, alternately from about 0.94: 1 to about 1.08: 1, alternately from about 0.97: 1 to about 1.05: 1. In one embodiment the chromium compound is chromium (III) 2-ethylhexanoate. The weight percent of chromium is in the range of about 10.3% by weight to 12.8% by weight; alternatively from 10.4% by weight to 11.8% by weight; alternatively from 10.5% by weight to 11.2% by weight. The amount of chromium oligomers is low such as the chromium compound demonstrates solubility in methanol. The amount of free acid is below 50 weight percent; alternatively below 30 weight percent; alternatively below 20 weight percent. Insoluble particles in hexane, are below 1 weight percent; alternatively below 0.5 percent by weight; alternatively below 0.2 percent by weight. The water content is below 1 weight percent; alternatively, below 0.5 percent by weight; alternatively, below 0.2 percent by weight. The pyrrole-containing compound can be any pyrrole-containing compound that will react with a chromium salt to form a pyrrole chromium complex. The pyrrole-containing compound includes pyrrolid hydrogenated, for example, pyrrole (C4H5N), pyrrole derivatives, as well as metal pyrrolide complexes, alkali metal pyrro lides, alkali metal pyrro lide salts or combinations thereof. A pyrrolid (or a pyrrole) can be any compound comprising a 5-element nitrogen containing heterocycle, such as pyrrole, pyrrole derivatives, substituted pyrrole and mixtures thereof. Broadly, the pyrrole-containing compound may be pyrrole, any heteroleptic or homologous metal complex or salt containing a pyrrole or ligand radical, or combinations thereof. Generally, the pyrrole-containing compound will have from about 4 to about 20 carbon atoms per molecule. Pyrroles (or pyrroles) include hydrogen pyrrolide (pyrrole), pyrrole derivatives, substituted pyrrolides (or pyrroles), lithium pyrrolide, sodium pyrrolide, potassium pyrrolide, cesium pyrrolide, substituted pyrrolide salts or combinations thereof . Examples of substituted pyrrolides (or pyrroles) include, but are not limited to, pyrrole-2-carboxylic acid, 2-acetylpyrrole, pyrrole-2-carboxaldehyde, tetrahydroindole, 2,5-dimethylpyrrole, 2,4-dimethyl-3-ethylpyrrole , 3-acetyl-2,4-dimethylpyrrole, ethyl-2,4-dimethyl-5- (ethoxycarbonyl) -3-pyrrole-propionate, ethyl-3,5-dimethyl-2-pyrrole-carboxylate.

In one embodiment, the pyrrole-containing compound is 2,5-dimethylpyrrole. The content of 2,5-dimethylpyrrole is greater than 98 weight percent; alternatively greater than 99.0 weight percent; alternatively greater than 99.5 weight percent. The water content of the pyrrole-containing compound is below 1 weight percent; alternatively below 0.5 percent by weight; alternatively below 0.01 weight percent. The color of the pyrrole-containing compound (Platinum-Cobalt Number) is below 200; alternatively below 120; alternatively below 80. In one embodiment, the pyrrole-containing compound used in an oligomerization catalyst system, comprises a di-pyrrolidone compound, for example one or more compounds represented by the following general structures: Structure II DI Stretch wherein, each R1-R6 can independently be H, or an aromatic group C? -C20, or any of the two adjacent to each other, taken together with the carbon atom to which they are attached can form an aromatic or non-aromatic ring. Y is a structural bridge having 1 to 20 carbon atoms and may include linear, branched or paraffinic cyclic or aromatic or cyclic paraffinic or aromatic containing structures and may include heteroatoms such as oxygen or sulfur in the form of linear, branched or cyclic ether, silyl, sulfur, sulfone, sulfoxide. In one embodiment shown as Structure (I), R1, R3, R4 and R6 are a methyl group, R2 and R5 are hydrogens, and Y = (CH2) n where n = l-10. In one embodiment shown as Structure (II), R1 and R6 are methyl groups, R2-R5 are hydrogens, and Y = (CH2) n where n = l-10. In a modality shown as Structure (III), R1, R3 and R5 are methyl groups, R2, R4 and R6 are hydrogen, and Y = (CH2) n where n = l-10.

The use of the dimeric pyrroles can produce a catalyst system with activity and selectivity for a desired oligomerized product, such as, for example, trimerization of ethylene to 1-hexene, as well as low polymer production. The alkyl metal, sometimes referred to as an activating compound, can be a heteroleptic or homologous alkyl metal compound of any of the aluminum, boron, lithium, magnesium or zinc metals. The alkyl metal can be any metal halide such as DEAC; a non-halide alkyl metal such as TEA; or combinations thereof. One or more alkyl metals can be used. The ligand (s) in the metal can be aliphatic, aromatic or combinations thereof. For example, the ligand (s) can be any saturated or unsaturated aliphatic radical. The alkyl metal can be a compound that can be considered both a Lewis acid and an alkyl metal. As used in this description, a Lewis acid can be defined as any compound that can be an electron acceptor. Activating compounds which are both an alkyl metal and a Lewis acid include alkylaluminum, alkylmagnesium, alkylzinc, alkyllithium compounds combinations thereof. The alkyl metal can have any number of carbon atoms. However, due to commercial availability and ease of use, the alkyl metal will usually comprise less than about 70 carbon atoms per alkyl metal molecule and alternatively less than about 20 carbon atoms per molecule. In one embodiment, the alkyl metals are not hydrolyzed, ie they are not pre-connected with water, such as alkylaluminum compounds, derivatives of alkylaluminium compounds, halogenated alkylaluminium compounds and mixtures thereof to improve the selectivity of the product, as well as improving the reactivity, activity, productivity of the catalyst system or combinations thereof. In one embodiment the alkyl metal can be a non-halide alkyl metal, an alkyl metal halide, a non-hydrolyzed alkylaluminum compound, a hydrolyzed alkylaluminum compound or combinations thereof. Suitable non-halide alkyl metals include, but are not limited to, alkyl aluminum compounds, alkyl boron compounds, alkylmagnesium compounds, alkyl zinc compounds, alkyllithium compounds or combinations thereof. Suitable non-halide alkyl metals include, but are not limited to, n-butyllithium, s-butyllithium, t-butyllithium, diethylmagnesium, dibutylmagnesium, diethylzinc, triethylaluminum, trimethylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum ethoxide, diethylaluminum phenoxide and mixtures thereof. Suitable alkyl metal halide compounds include, but are not limited to, ethylaluminum dichloride, diethylaluminum chloride, diethylaluminum bromide, diethylaluminum sesquichloride, diisobutylalumium chloride, ethylaluminum sesquichloride, diethylaluminum bromide, diethylaluminum iodide, ethylaluminummethoxychloride, and mixtures thereof. In one embodiment, the alkylaluminum compound can be triethylaluminum. When a trimerization catalyst system can be the desired product, the alkyl metal can be at least one non-hydrolyzed alkylaluminum compound, expressed by the general formulas A1R3, A1R2X, A1RX2, A1R20R, A1RXOR, Al2R3X3, or combinations thereof, in where R can be an alkyl group and X can be a halogen atom. Suitable compounds include, but are not limited to, triethylaluminum, triethylaluminum, tripropylaluminum, tri-n-butylaluminum, tri-isobutylaluminum, tri-n-hexylaluminum, tri-n-octylaluminum, diethylaluminum chloride, diethylaluminum bromide, methoxide diethylaluminum, diethylaluminum phenoxide, ethylaluminum methoxychloride, ethylaluminum dichloride, diethylaluminum chloride, diethylaluminum bromide, atilaluminum sesquichloride, or combinations thereof. In one embodiment, the activating compound for an oligomerization catalyst system may be a trialkylaluminum compound, A1R3, for example, triethylaluminum. Additionally, hydrolyzed alkylaluminum compounds, aluminum alkanes can be used. Aluminaxanes can be prepared as is known in the art by reacting water or water containing materials with alkylaluminium compounds. Suitable aluminaxanes are prepared from trialkylaluminum compounds such as trimethylaluminum, triethylaluminum, tripropylaluminum, tributylaluminum, triisobutylaluminum, trihexylaluminum or the like, and mixtures thereof. Mixtures of different aluminaxanes can also be used. Suitable hydrolyzed alkylaluminum compounds include, but are not limited to, methylaluminioxane, modified methylaluminumxane and ethylaluminumxanes and mixtures thereof. The olefin oligomerization catalyst systems may also comprise a catalyst support. A supported chromium catalyst system can be prepared with any support useful for supporting a chromium catalyst. Suitable catalyst supports include, but are not limited to, zeolites, inorganic oxides, either alone or in combination, phosphated inorganic oxides and mixtures thereof, for example silica, silica-alumina, alumina, fluorinated alumina, alumina silatada, toria, aluminiofosfato, aluminum phosphate, phosphatized silica, phosphatized alumina, silica-titanium, silica / coprecipitated titanium, fluorinated / silated alumina and mixtures thereof. In one embodiment, the catalyst support is aluminophosphate. The solvent may be a hydrocarbon solvent, a halogenated hydrocarbon solvent, or combinations thereof, usually having no more than 30 carbon atoms. Specific examples of the solvents may include saturated aliphatic and alicyclic hydrocarbons such as isobutane, pentane, n-hexane, hexanes, cyclohexane, n-heptane or n-octane, aliphatic and alicyclic unsaturated hydrocarbons such as 2-hexene, cyclohexene or cyclo-octene , aromatic hydrocarbons such as toluene, benzene or xylenes, ortho-xylene, meta-xylene, paraxylene, chlorobenzene, halogenated hydrocarbons such as carbon tetrachloride, chloroform, methylene chloride or chlorobenzene or dichlorobenzene or the like. In one embodiment, the hydrocarbon solvent may be a halogenated aromatic or aromatic compound having between about 6 to about 20 carbon atoms, a saturated or unsaturated hydrocarbon having from about 3 to about 14 carbon atoms; a halogenated saturated hydrocarbon that has about 1 to about 9 carbon atoms; or combinations thereof. The solvent may be a hydrocarbon such as cyclohexane, isobutane, n-hexane, hexanes, n-heptane, heptanes, pentane or mixtures thereof. In one embodiment, the solvent is ethylbenzene. In one embodiment, the solvent is tetradecane. In one embodiment, alpha olefins can be used as the solvent, for example, 1-hexene. In one embodiment, the solvent may comprise normal and / or isomeric mixtures of butane, hexene, decene, dodecene, tetradecene or combinations thereof. In one embodiment, the hydrocarbon compound is used as a solvent which can be any combination of one or more aromatic or aliphatic unsaturated hydrocarbon compounds. While not wishing to be bound by theory, it can be believed that an unsaturated hydrocarbon compound acts as more than a solvent, and can be a reagent, a stabilizing component, or both, either during, subsequently or both, to the formation of a inventive catalyst system. Suitable unsaturated hydrocarbon compounds can be any of the unsaturated hydrocarbon compounds that can solubilize the catalyst system. In one embodiment, aromatic compounds having from about 6 to 20 carbon atoms per molecule, can be used as a solvent in combination with any unsaturated aliphatic hydrocarbon comprising less than about 20 carbon atoms per molecule. Specific unsaturated aliphatic compounds include ethylene, 1-hexene, 1,3-butadiene and mixtures thereof. In one embodiment, the unsaturated aliphatic hydrocarbon compound can be ethylene, which can be either a solvent or a reagent. Specific unsaturated aromatic hydrocarbon compounds include, but are not limited to, toluene, benzene, ortho-xylene, metaxylene, para-xylene, ethylbenzene, xylene, mesitylene, hexamethylbenzene, and mixtures thereof. The halide-containing compound may be any compound containing a halogen, for example organohalides (including those listed as suitable solvents); no organohalides; metal halides (which include alkyl metal halides such as those previously described and non-alkyl metal halides such as tin tetrachloride and magnesium chloride); non-metallic halides; or combinations thereof. Suitable compounds include, but are not limited to, compounds with a general formula RmXn, wherein R can be any radical, inorganic radical or both, X can be a halide, selected from fluoride, chloride, iodide or combinations thereof, and m and n each are numbers greater than 0.

Where R is an organic radical, R can have from about 1 to about 70 carbon atoms per radical, alternatively from 1 to 20 carbon atoms per radical, for better compatibility and catalyst system activity. Where R is an inorganic radical, R can be selected from aluminum, silicon, germanium, hydrogen, boron, lithium, tin, gallium, indium, lead and mixtures thereof. In one embodiment, the halide-containing compound is a chloride-containing compound such as DEAC or organochlorides. Specific organohalide compounds include, but are not limited to, methylene chloride, chloroform, benzylchloride chlorobenzene, carbon tetrachloride, chloroethane, 1,1-dichloroethane, 1,2-dichloroethane, tetrachloroethane, hexachloroethane, 1,4-diol. bromobutane, 1-bromobutane, aryl, chloride, carbon tetrabromide, bromoform, bromobenzene, iodomethane, di-iodomethane, hexafluorobenzene, trichloro-acetone, hexachloro-acetone, hexachloro-cyclohexane, 1,3,5-trichloro-benzene, hexachloro- benzene, triethyl chloride or mixtures thereof. Specific non-alkyl metal halides include but are not limited to silicon tetrachloride, tin (II) chloride, tin (IV) chloride, germanium tetrachloride, boron trichloride, scandium chloride, yttrium chloride, lanthanum chloride, titanium tetrachloride, zirconium tetrachloride, hafnium tetrachloride, aluminum chloride, gallium chloride, silicon tetrachloride, tin tetrachloride, phosphorus trichloride, antimony trichloride, trityl-hexachloro-antimonate, antimony pentachloride, bismuth trichloride, boron tribromide, silicon tetrabromide, aluminum fluoride, molybdenum pentachloride, tungsten hexachloride, aluminum trichloride, aluminum trichloride or combinations thereof. Specific metal halide compounds include diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, mixtures of non-halide metal halides and metal halides, trimethylchlorosilane, tributyl tin chloride, dibutyl tin dichloride or combinations thereof. In addition, the chromium-containing compound, the alkyl metal or solvent may contain and provide a halide to the reaction mixture. For example, the halide source can be an alkylaluminum halide and can be used in conjunction with alkylaluminum compounds. Suitable alkylaluminium halides include, but are not limited to, diisobutylaluminum chloride, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum bromide, diethylaluminum iodide, and mixtures thereof. The amount of each reagent used to prepare An oligomerization catalyst system can be any amount sufficient that, when combined to form the catalyst system, the oligomerization occurs in contact with one or more olefins. Generally, a molar excess of the alkyl metal is used. In one embodiment, it is expressed as a molar ratio, in terms of moles of nitrogen (N) in the pyrrole compound to moles of metal (M) in the alkyl metal, usually at least a molar ratio of 1: 150 is used. In one embodiment, the metal (M) is aluminum. In one embodiment, the N: M molar ratio is from about 1: 1 to about 1:50, alternately from about 1: 1 to about 1:20, or alternatively from about 1: 1 to about 1:10. Generally, the amount of alkyl metal / pyrrole solution used is determined based on the moles of chromium. In one embodiment, it is expressed as a molar ratio, in terms of moles of chromium (Cr) to moles of nitrogen (N) in the pyrrole compound to moles of metal (M) in the alkyl metal, ie Cr: N: M, the ratio of the chromium-containing compound to the pyrrole-containing compound is at least about 1:15 and the ratio of the chromium-containing compound to the alkyl metal is at least about 1: 150, such as Cr: NM is at least about 1. : 15: 150. In one embodiment, the molar ratio of Cr: N: M is within the range of about 3: 3: 3 (also expressed as about 1: 1: 1) to about 1: 3: 100; alternatively, the molar ratio of Cr: N: M is within the range of 1: 3: 9 to 1: 3: 21. In one embodiment, to prepare an oligomerization catalyst system, about one mole of chromium, such as the chromium element (Cr), can be contacted with about 1 to about 50 moles of the pyrrole-containing compound and about 1 to about 75 moles. of aluminum, as the element, optionally in an excess of unsaturated hydrocarbon. The halide source may be present in an amount of about 1 to about 75 moles of halide, as the element. In one embodiment, about 1 mole of chromium, calculated as the chromium element (Cr), can be contacted with about 15 moles of the pyrrole-containing compound; about 5 to about 40 moles of aluminum, calculated as the aluminum (Al) element; and about 1 to about 30 moles of the halide-containing compound, calculated as the halide element (X); in an excess of unsaturated hydrocarbon. In one embodiment, about one mole of chromium, such as the element (Cr), can be contacted with two to four moles of the pyrrole-containing compound; 10 to 2 moles of aluminum, as the element (Al); and 2 to 15 moles of halide, as an element (X); in an excess of unsaturated hydrocarbon. The ratio of pyrrole to chromium (Py.Cr) in the final catalyst composition recovered as the product of various embodiments described herein, is referred to as the final molar ratio of Py: Cr. The final molar ratio of Py: Cr of the catalyst may be in the range of from about 1.0: 1 to about 4.0: 1; alternatively from about 1.5: 1 to about 3.7: 1; alternatively from about 1.5: 1 to about 2.5: 1; alternatively from about 2.0: 1 to about 3.7: 1; alternatively from about 2.5: 1 to about 3.5: 1; or alternatively from about 2.9: 1 to about 3.1: 1. The synthesis of the catalyst prepared in a hydrocarbon solvent can be referred to as a solution of the catalyst system. The resulting catalyst system, prior to introduction to any of the reagents, can have a chromium concentration of approximately less than about 50 mg Cr / ml of catalyst system solution, for example, of about 0.005 g Cr / ml of the solution from the catalyst system to approximately 25 mg Cr / ml of the catalyst system solution, alternatively of approximately 0.1 g Cr / ml of the catalyst system solution up to approximately 25 mg Cr / ml of the catalyst system solution, alternatively from approximately 0.5 mg Cr / ml of the catalyst system solution to approximately 15 mg Cr / ml of the catalyst system solution , or alternatively from about 1 mg Cr / ml of the catalyst system solution to about 15 mg Cr / ml of the catalyst system solution. Catalysts prepared in accordance with the present disclosure can be used for the oligomerization of olefins, for example, alpha olefins. Oligomerization of the olefins can be conducted by any of the suitable oligomerization methods. In one embodiment, an oligomerization catalyst is contacted with one or more olefins in a reaction zone under suitable reaction conditions (e.g., temperature, pressure, etc.) to oligomerize the olefins. Linear or branched alpha olefins having from 2 to 30 carbon atoms can be used as the raw material of olefins. Specific examples of alpha olefins may include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 3-methyl-1-butene, 4-methyl-1-pentene or the like. When ethylene is used as the alpha olefin, it is possible to produce 1-hexene as an ethylene trimer with a high yield and a high selectivity. In the above description, similar parts are marked through the specification and the drawings with the same numerical reference, respectively. The figures of drawings are not necessarily to scale. Certain characteristics of the invention can be shown exaggeratedly in scale or in a little schematic form and some details of the conventional elements can not be shown with the interest of clarity and consistency. The present description is susceptible to modalities of different forms. Shown in the drawings, and in this document, specific embodiments of the present description are described in detail with the understanding that the present description is considered an exemplification of the principles of the invention, and is not intended to limit the illustrated invention. and described in this document. It will be widely recognized that the different teachings of the modalities discussed above can be employed separately or in any suitable combination to produce the desired results. Specifically, the present disclosure for a method for making a catalyst by contacting catalyst components will not be limited by any of several described embodiments. Various modalities shown in the figures can be combined. For example, ways to reduce water, acidic protons or both, shown in Figs. 2A-2D and 3A-3B can be combined with the volume addition modalities of Figs. 1A-1D or the simultaneous addition modes of Figs. 4A-4E. Additionally, various modes for reducing water can be combined in any desired number and sequence, for example azeotropic distillation followed by contact with a non-halide alkyl metal (e.g., TEA), contact with an adsorbent, or both in any order; contact with a non-metallic halide followed by contact with an adsorbent (or vice versa); azeotropic distillation before, after or between contact with a non-metallic halide, followed by contact with an adsorbent; etc. Modes can be integrated to reduce water, acidic protons or both, addition of volume and simultaneous addition in any number and sequence desirable and operable in other modalities. The method described herein is to make an oligomerization catalyst that can be useful in any suitable reaction such as the reaction is an oligomerization reaction. In one embodiment, the method of the present disclosure is for a trimerization catalyst for use in a trimerization reaction that produces 1-hexene from ethylene and the above detailed description can be focused on this embodiment but with the understanding that the present invention can have wide applications.

EXAMPLES Having generally described the preparation of an oligomerization catalyst, the following examples are given as particular embodiments of the catalyst described and to demonstrate the practice and advantages thereof. It will be understood that the examples are given by way of illustration and are not intended to limit the following specification or claims in any way. Various embodiments are shown for preparing the oligomerization catalyst in Examples 1 to 14. In Example 1, the selective 1-hexene catalyst is prepared at various temperatures and concentrations of chromium. In example 2, the selective 1-hexene catalyst is prepared by the simultaneous addition of chromium / ethylbenzene and TEA / DEAC / pyrrole / ethylbenzene for the rest of the catalyst previously prepared. In Example 3, the selective 1-hexene catalyst is prepared using a ratio of pyrrole: chromium of 6: 1 for the first half of the addition of chromium / pyrrole and a ratio of pyrrole: chromium of 0 during the second half of the addition of chromium / pyrrole. In Example 4, the selective 1-hexene catalyst is prepared by the simultaneous addition of all the catalyst components. At Example 5, chromium compounds containing various amounts of water and chromium oligomers are used in the preparation of the selective 1-hexene catalyst. In Example 6, the selective 1-hexene catalyst is prepared by separating the simultaneous addition of the pyrrole and chromium components to a solution of TEA and DEAC. In example 7, the selective 1-hexene catalyst is enhanced when a small amount of TEA is added to the chromium component and water, acidic protons or both are reduced. In Example 8, water, acidic protons or both are reduced in the preparation of the selective 1-hexene catalyst by contacting a small amount of TEA with the chromium / pyrrole solution. In Example 9, the preparation of the selective 1-hexene catalyst is made by varying the pyrrole: chromium ratio during the addition to TEA / DEAC. In Example 10, the preparation of the selective 1-hexene catalyst is made using high initial contact ratios pyrrole: chromium when contacted with TEA / DEAC. In example 11, the preparation of the selective 1-hexene catalyst is made using simultaneous separate addition of catalyst components to the rest of the catalyst previously prepared. In Example 12, preparation of the selective 1-hexene catalyst is made with the addition of a nitrogen compound to the alkylaluminum compound to solubilize products resulting from the reaction of water and aluminum alkyls. In Example 13, water is reduced when the pyrrole and the chromium components are contacted to reduce the viscosity of the chromium components, facilitating the removal of water using molecular sieves. In Example 14, water is reduced by azeotropic distillation to remove water from the chromium catalyst component. In example 15, the impact of catalyst time on the purity of 1-hexene is described. Several of the above examples also include the mode for the addition of chromium and / or pyrrole to alkylaluminums. In the following examples, the catalyst was prepared using one of two established apparatuses. An established apparatus is a laboratory at an established scale to prepare the catalyst in small amounts, for example 100 ml, which is typically used for research purposes. The other established device is an established scale pilot plant, typically designed to prepare large quantities of the catalyst, for example 13.24 liters (3.5 gallons), which will be suitable for use in a pilot plant. The laboratory at a set scale prepares the catalyst in a dry box in which the atmosphere inside the box is controlled with a helium blanket that is kept free of oxygen and moisture, which can be determinant for catalyst components, prepared catalysts or both. All the laboratory scale catalyst preparation processes described in the examples below are carried out in glassware in a dry box. Once the catalyst is prepared, it is diluted with cyclohexane to the desired concentration for oligomerization reactor tests. The diluted catalyst solution is then transferred into a 300 cc metal cylinder to provide the means for transporting the catalyst an oligomerization reactor under a protected atmosphere. It is noted that any transfer of components via syringe described in the examples below is done in the dry box. The established scale pilot plant prepares the catalyst under a blanket of nitrogen to control the atmosphere, keeping it free of oxygen and moisture. All the catalyst preparation processes in the pilot scale plant, described in the following examples, are carried out in a 18.927 liter (5 gallon) reactor comprising a steel alloy autoclave. Once the catalyst is prepared it is filtered in a metal cylinder of 18,927-37,854 liters (5-10 gallons). Approximately 150 grams of the prepared catalyst are then transferred from the large cylinder to a smaller one, 300 cc, from the metal cylinder and are transported to a dry box with helium blanket as described above. The prepared catalyst is transferred into glassware and diluted with cyclohexane to the desired concentration to be tested in the oligomerization reactor. The diluted catalyst solution is then transferred to a 300 cc metal cylinder and transported to an oligomerization reactor. In a previous example, the prepared catalyst is tested in either a batch or a continuous oligomerization reactor. The batch oligomerization reactor is a 1 liter autoclave that is sealed and under a blanket of nitrogen. It has a magnetic stirring device to stir the contents of the sealed container. The solution of the prepared catalyst is transported to the oligomerization reactor in the 75 c metal cylinder. The solvent is charged, for example, cyclohexane to the oligomerization reactor, and the catalyst is transferred to the reactor by connecting the cylinder to the reactor and pressurizing the cylinder with ethylene, which carries the catalyst into the reactor. The oligomerization reactor is pressurized with 650 psi of ethylene and 50 psi of hydrogen, and is operated at a temperature of approximately 115 ° C. In some of the above examples, a continuous oligomerization reactor is used to test the prepared catalyst. The oligomerization continues performs by controlling all feeds to the reactor using separate controllers for each feed component. The hydrogen is fed to the reactor at a rate of about 0.5 1 / h, and the ethylene is fed to the reactor at a rate of about 497 g / h. The reactor is either a 1 liter or 1 gallon autoclave, depending on the desired residence time in the reactor. The reaction temperature is approximately 115 ° C, and the pressure is approximately 800 psig. The samples in the production line of the continuous oligomerization reactor are collected via liquid sampling valves (manufactured by Valco) and fed to gas chromatography in the line (GC), Hewlett Packard 6890, for analysis. The production samples were analyzed by the GC for the amount of ethylene present, hexane present and C isomers and larger oligomers present. From this information, the selectivity, purity and conversion are calculated. Selectivity (1-C6 =) refers to the weight percentage of ethylene converted to 1-hexene. Purity (1-C6 = / C6) refers to the weight percentage of 1-hexene in the total of all Ce-Conversion isomers (C2 =) refers to the weight percentage of ethylene has been converted to oligomer product (per example, hexene or tens, etc.). Productivity refers to how much of the 1-hexene in the catalyst is produced, and refers to the amount of the catalyst used. The productivity is quantified in grams of 1-hexene per gram of chromium (g, l-C6 = / g Cr). In the batch process, the productivity is evaluated during 30 minutes of time frame. Other evaluations made in the examples of the processed oligomerization catalyst include the reactor polymer (polymer Rx) and total polymer. At the end of each day, the reactor was opened and cleaned. Any polymer formed within the reactor was collected, allowed to dry and then weighed. This quantity was then reduced to a commercial size processing unit of 453600000 kilograms / year (100 000 000 pounds / year) and reported as reactor polymer, quantified in kilograms per hour expected at a 453600000 kilogram plant per year (Plant Kg / h lOOMN / year). A filter comprising a stainless steel pad placed downstream of the reactor was also removed, dried and weighed at the end of each day for amounts of polymer. This amount of polymer was then reduced to a plant of 45,300,000 Kg / year (1,000,000,000 lbs / year) and added to the amount of polymer from the reactor by reporting the total polymer, quantified in kilograms per hour expected a plant of 4,536,000,000 Kg. year (Plant Kg / h lOOMN / year). To determine the presence of hydration water in some of the samples, a infrared analysis using a standard IR device. The IR band for water that forms complexes, for example, of about 1450 cirf1 of hydration, is almost the band of chromium oligomers, making it difficult to distinguish the two. Therefore, in some cases a methanol solution test is performed for precipitation of chromium oligomers to help evaluate the samples in the line to determine the presence of water of hydration.

Example 1 Catalysts 1-8: The catalyst was prepared by adding 6.3957 kg (14.1 Ib) of dry purged toluene with nitrogen to a 18.927 liter (5 gallon) reactor. 630.9 g of chromium (III) 2-ethylhexanoate dissolved in 750 ml of toluene was added to toluene, followed by 300 ml of rinsed toluene. 2,5-Dimethylpyrrole (388.9 ml) was added to the chromium solution in the reactor. The reactor was purged with nitrogen and brought to a temperature of 25 ° C. Then a mixture of 1600 g of pure triethylaluminum (TEA) and 1229 g of pure diethylaluminum chloride (DEAC) was added to the reactor followed by 0.0907 kg (0.2 Ib) of rinsed toluene. The temperature was increased 18 ° C and returned to 25 ° C with cooling. The contents of the reactor were left overnight and then filtered, using a filter comprising a combination of a metal screen, paper filter, fiberglass, diatomaceous earth and another layer of fiberglass. Additional catalysts were prepared in which the temperature and chromium concentration of the catalyst preparations are varied. The catalysts were tested for productivity in a continuous reactor of 3.7854 liters (1 gallon) and the results are shown in Table 1.

Table 1 The examples show that the catalyst productivity increases with a reduction in catalyst preparation temperature. Additionally, the examples show the best catalyst productivity observed in catalyst 3 and catalyst 7 with 45.769 g 1-C6 = / g Cr and 43.373 g l-C6 = / g Cr, respectively, when prepared at low temperature (25 ° C ) and high concentration of chromium (5 mg Cr / ml). Polymer was also observed lower reactor, under the best conditions of productivity.

Example 2 Catalysts 9-10: An ethylbenzene solution containing 2.3 g of chromium 2-ethylhexanoate was prepared (III) and 8.13 g of ethylbenzene. A separate solution containing 6.05 g of pure triethylaluminum (TEA), 4.63 g of pure diethylaluminum chloride was also prepared (DEAC), 1.37 g of 2,5-dimethylpyrrole and 22.6 g of ethylbenzene. These two solutions were added to 30.98 g of the active catalyst over a period of 40 minutes such that the addition time for both solutions start and end at the same time. The catalyst was tested in a continuous reactor of 1 1 and the average results of the two tests performed in Table 2 are shown as Catalyst 10. The average of the two tests performed of a standard catalyst preparation is shown in Table 2 as Catalyst 9 Table 2 The examples show that an acceptable catalyst can be prepared. The examples further indicate that a smaller number of tanks may be required to prepare the catalyst.

Example 3 Catalyst 11: A mixing solution was prepared 12. 10 g of pure triethylaluminum (TEA), 9.38 g of pure diethylaluminum chloride (DEAC) and 20.02 g of ethylbenzene. Two aliquots were added to this solution. The first contains 2.3 g of chromium (III) 2-ethylhexanoate, 1.14 g of ethylbenzene and 2.74 g of 2,5-dimethylpyrrole. The second contains 2.3 g of chromium (III) 2-ethylhexanoate and 1.14 g of ethylbenzene. Ethylbenzene was added to obtain a total volume of 100 ml. The catalyst prepared by this method was tested in a continuous reactor of 1 1. The average results of three tests performed are shown in Table 3.

Table 3 The examples show high selectivity (91.2%), high purity (99.2%) and good catalyst productivity (80,759, 1-C6 = g Cr) for the preparation of the catalyst.

Example 4 Catalyst 12: Ethylbenzene (10.67 g) was added to a dry 100 ml volumetric flask. Individual chemicals were added to each of four separate 20 ml syringes. The added chemicals are 4.76 g of chromium (III) 2-ethylhexanoate dissolved in 2.38 g of ethylbenzene, 12.06 g of pure triethylaluminum (TEA), 9.26 g of pure diethylaluminum chloride (DEAC) and 2.74 g of 2,5-dimethylpyrrole . Sufficient ethylbenzene was added to each of these syringes to provide a total volume of 19-20 ml. The needles of the syringes were added to the 100 ml volumetric flask and the syringes were emptied into the flask simultaneously at the same ratio for 30 minutes. After the addition was complete, ethylbenzene was added to the flask to obtain a total volume of 100 ml. The catalyst (1 ml) prepared by this method was tested in a batch reactor of 1 1 at 116 ° C and 680 psig. The results of this test are shown in Table 4.

Table 4 Example 5 Catalysts 13-15: The catalyst was prepared by adding 15.85 g of ethylbenzene to a dry 100 ml volumetric flask. To this flask was added 12.09 g of pure triethylaluminum (TEA), 9.26 g of pure diethylaluminum chloride (DEAC) and 2.74 g of 2, 5-dimethylpyrrole. To this mixture was added 4.76 g of chromium (III) 2-ethylhexanoate dissolved in 2.38 g of ethylbenzene. The volume was brought to 100 ml with ethylbenzene. The different preparations of chromium (III) 2-ethylhexanoate were used to prepare the catalysts 13-15. In catalyst 13, the chromium content of chromium (III) 2-ethylhexanoate is 10.5%. Infrared analysis and a methanol solubility test indicate that some water of hydration is present but not chromium oligomers. In the catalyst 14, the chromium content is 10.9% and the infrared analysis and the solubility of methanol indicates that neither water of hydration nor chromium oligomers are present. In the catalyst 15, the analysis indicates the presence of chromium oligomers. The prepared catalyst was tested for activity in the continuous reactor (11) and the average results for two tests performed for each preparation are shown in Table 5.

Table 5 The examples show that the best combination of purity and productivity is obtained when the water of hydration and chromium oligomers are not contained in chromium (III) 2-ethylhexanoate in significant amounts.

Example 6 Catalyst 16: Ethylbenzene (20.01 g) was added to a 125 ml Erlenmeyer flask equipped with a magnetic stirrer. Ethylbenzene was added, 12.07 g of pure tributylammonium and 9.27 g of diethylaluminum chloride. In a 10 ml syringe, 4.61 g of chromium (III) 2-ethylhexanoate dissolved in 2.28 g of ethylbenzene was added. In a separate 10 ml syringe, 2.73 g of 2,5-dimethylpyrrole and 3.38 g of ethylbenzene were added. Both syringes have an approximate volume of 7.5 ml. The needles of the syringes were placed on opposite sides of the Erlenmeyer flask containing the diluted aluminum alkyls and the contents were added simultaneously for 30 minutes. After the addition was complete, the contents were transferred into a 100 ml volumetric flask and diluted to approximately 103 ml with ethylbenzene. This catalyst was tested in a continuous 1 1 reactor and the results (average of three tests performed) are shown in Table 6.

Table 6 Example 7 Catalyst 17: Pure triethylaluminum was added (TEA, 0.27 g) to 30.01 g of ethylbenzene. This solution was slowly added to 4.62 g of chromium 2-ethylhexanoate (III) dissolved in 2.27 g of ethylbenzene. This is a sufficient amount of TEA to react with water and excess acid present in chromium 2-ethylhexanoate (III). The chromium solution, after the reaction with TEAS, was added for 50 minutes to a solution containing TEA (11.81 g), diethylaluminum chloride (DEAC, 9.27 g), 2,5-dimethylpyrrole (2.75 g) and ethylbenzene ( 25.01 g). Subsequently, ethylbenzene was added to provide a total volume of 100 ml. Catalyst 18: A comparison catalyst was prepared by adding 30.02 g of ethylbenzene to 4.62 g of 2- Chromium (III) ethylhexanoate dissolved in 2.27 g of ethylbenzene. The chromium solution was added over 50 minutes to a solution containing TEA (12.08 g), diethylaluminum chloride (DEAC, 9.28 g), 2,5-dimethylpyrrole (2.74 g) and ethylbenzene (25.00 g). Ethylbenzene was subsequently added to provide a total volume of 100 ml. These catalysts were tested for productivity in a continuous reactor of 1 1. The average of two separate runs of each catalyst is shown in Table 7.

Table 7 The addition of TEA to a solution of chromium (III) 2-ethylhexanoate provides a catalyst with increased activity. Corrosion in the equipment will also be reduced after the catalyst has been inactivated. The example also provides an example of adding TEA to chromium to reduce water, acidic protons or both.

Example 8 Catalyst 19: Pure triethylaluminum was added (TEA, 0.43 g) to 2.01 g of ethylbenzene. This solution was slowly added to 4.62 g of chromium 2-ethylhexanoate (III) in 27.27 g of ethylbenzene. This is a small excess of the amount of TEA sufficient to react with water and excess acid present in chromium 2-ethylhexanoate (III). To this chrome / TEA solution was added 2.73 g of 2,5-dimethylpyrrole. The solution chromium / TEA / dimethylpyrrole was added for 30-40 minutes, to a solution containing TEA (11.62 g), diethylaluminum chloride (DEAC, 9.25 g) and ethylbenzene (15.00 g). Then ethylbenzene was added to provide a total volume of 100 ml. Catalyst 20: A comparison catalyst was prepared by adding 2.74 g of 2,5-dimethylpyrrole to 4.61 g of chromium (III) 2-ethylhexanoate dissolved in 2.27 g of ethylbenzene. An immediate reduction in the viscosity of the chromium solution was observed. This chromium solution was added for 30-40 minutes, to a solution containing TEA (12.08 g), diethylaluminum chloride (DEAC, 9.27 g) and ethylbenzene (20.00 g). Then ethylbenzene was added to provide a total volume of 100 ml. These catalysts were tested for productivity in a continuous 1 1 reactor. The average of three separate run tests for each catalyst are shown in Table 8.

Table 8 The addition of TEA provides a catalyst with increased activity. The corrosion of downstream equipment can be reduced after the catalyst is inactivated.

Example 9 Several catalysts 21-23 were prepared in which the molar ratio of 2,5-dimethylpyrrole / chromium is varied during the addition to the solution of aluminum alkyls. Catalyst 21: A chromium solution of 4.61 of chromium (III) 2-ethylhexanoate dissolved in 2.27 g of ethylbenzene was divided into four equal portions of 1.72 g each. To each of these portions a different amount of 2,5-dimethylpyrrole was added. To the first one, 1.52 g of 2,5-dimethylpyrrole was added, to the second 0.84 g, to the third 0.27 g and to the fourth 0.12 g. The chromium / 2, 5-dimethylpyrrole portions were then sequentially added to a solution containing 12.07 g of pure triethylaluminum (TEA), 9.29 g of pure diethylaluminum chloride (DEAC) and . 01 g of ethylbenzene. The total addition time is approximately 50 minutes. The resulting catalyst solution is diluted to 100 ml with ethylbenzene. The test results of this catalyst, in a continuous reactor of 1 1, are shown as Catalyst 21 in Table 9 below. The results shown are the average of four separate tests run. Catalyst 22: A chromium solution of 4.61 g of chromium (III) 2-ethylhexanoate dissolved in 2.27 g of ethylbenzene was divided into four portions. To each of these portions was added a different amount of 2,5-dimethylpyrrole and a similar amount of ethylbenzene. The first portion contains 0.69 g of chromium solution, 1.50 g of 2,5-dimethylpyrrole and 7.51 g of ethylbenzene. The second contains 1.38 g of chromium solution, 0.81 g of 2,5-dimethylpyrrole and 7.52 g of ethylbenzene. The third portion contains 2.06 g of chromium solution, 0.27 g of 2,5-dimethylpyrrole and 7.50 g of ethylbenzene. The fourth portion contains 2.75 g of chromium solution, 0.16 g of 2,5-dimethylpyrrole and 7.51 g of ethylbenzene. The chromium / 2, 5-dimethyl chromium / 2, 5-dimethylpyrrole / ethylbenzene portions were then added sequentially to a solution containing 12.07 g of pure triethylaluminum (TEA), 9.27 g of pure diethylaluminum chloride (DEAC) and 25.01 g of ethylbenzene. The total addition time is approximately 60 minutes. The resulting catalyst solution was then diluted to 100 ml with ethylbenzene. The test results of this catalyst, in a continuous reactor of 1 1, are shown as Catalyst 22 in Table 9 below. The results shown are the average of two tests run separately. Catalyst 23: A chromium solution of 4.61 g of chromium (III) 2-ethylhexanoate dissolved in 2.27 g of ethylbenzene was divided into four portions. To each of these portions was added a different amount of 2,5-dimethylpyrrole and a similar amount of ethylbenzene. The first portion contains 0.35 g of chromium solution, 1.53 g of 2,5-dimethylpyrrole and 7.51 g of ethylbenzene. The second contains 0.69 g of chromium solution, 0.81 g of 2,5-dimethylpyrrole and 7.49 g of ethylbenzene. The third portion contains 2.06 g of chromium solution, 0.27 g of 2,5-dimethylpyrrole and 7.51 g of ethylbenzene. The fourth portion contains 3.77 g of chromium solution, 0.15 g of 2,5-dimethylpyrrole and 7.50 g of ethylbenzene. The chromium / 2, 5-dimethylpyrrole / ethylbenzene portions were sequentially added to a solution containing 12.09 g of pure triethylaluminum (TEA), 9.26 g of pure diethylaluminum chloride (DEAC) and 25.02 g of ethylbenzene. The total addition time is approximately 60 minutes. The resulting catalyst solution was then diluted to 100 ml with ethylbenzene. The test results of this catalyst, in the continuous 1 1 reactor, are shown as Catalyst 23 in Table 9 below. The results shown are the average of two tests run separately.

Example 10 Catalyst 24: 6.6225 kilograms were added (14.6 lbs) of ethylbenzene purged with nitrogen to a dry 18.927 liter (5 gallon) reactor purged with nitrogen. The reactor was purged with nitrogen and a mixture consisting of 1592 g of pure triethylaluminum (TEA) and 1238 g of pure diethylaluminum chloride was added to the reactor. The aluminum alkyl mixing vessel was rinsed with 1397 g (0.2 lbs) of ethylbenzene and this rinse was added to the reactor. A chromium solution was prepared by adding 700 ml of ethylbenzene to 630.9 g of chromium 2-ethylhexanoate (III). The solution was stirred until the solution was obtained and transferred to a cylinder of 3.7854 1 (1 gallon) followed by a rinse of 75 ml of ethylbenzene. The cylinder, containing the chromium solution, was subjected to pressure and decompression several times with nitrogen. The mixture of chromium / 2,5-dimethylpyrrole (DMP) was added to the reactor in four batches of a chrome / DMP mixing tank. For the first batch, 65 g of chromium and 233 ml of DMP were added to the tank of mixing and then this mixture was added to the reactor in increments of 31-52 g with stirring and cooling so that the temperature does not exceed 22 ° C. For the second batch, 130 g of chromium and 97 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 48-58 g with stirring and cooling so that the temperature did not exceed 22 ° C. For the third batch, 326 g of chromium and 39 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 48-54 g with stirring and cooling so that the temperature did not exceed 22 ° C. For the whole batch, 789 g of chromium and 20 g of DMP were added to the mixing tank and then this mixture was added to the reactor in 100-130 g increments with stirring and cooling so that the temperature did not exceed 24 ° C. Ethylbenzene 453.6 g (1 Ib) was added to the chromium solution cylinder and used to rinse the chrome / DMP mixing tank. The ethylbenzene rinse was added to the reactor. The reactor was stirred for an additional 30 minutes. After standing overnight, the catalyst solution was filtered, using a filter as described above. The catalyst solution was tested for activity in a continuous 1 1 reactor. The results are shown as Catalyst 24 in Table 9 below. The results shown are the average of two tests run separately.

Example 11 Catalyst 25: To a dry 18.927 liter (5 gallon) reactor purged with nitrogen, 6.3504 kg (14.0 Ib) dry nitrogen purged ethylbenzene was added. The reactor was purged with nitrogen and a mixture consisting of 1283 g of pure triethylaluminum (TEA) and 990 g of pure diethylaluminum chloride (DEAC) was added to the reactor. The aluminum alkyl mixing vessel was rinsed with 90.72 g (0.2 Ib) of ethylbenzene and this rinse was added to the reactor. A chromium solution was prepared by adding 700 ml of ethylbenzene to 630.9 g of chromium (III) 2-ethylhexanoate. The mixture was stirred until the mixture was obtained and transferred to a 3,754 liter (1 gallon) cylinder followed by 75 ml of an ethylbenzene rinse. The cylinder, containing the chromium solution, was subjected to pressure and decompression several times with nitrogen. Chromium / 2, 5-dimethylpyrrole (DMP) mixtures were added to the reactor in four batches of a chrome / DMP mixing tank. For the first batch, 52 g of chromium and 187 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 20.52 g with stirring and cooling so that the temperature did not exceed 21 ° C. For the second batch, 104 g of chromium and 78 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 40-50 g with stirring and cooling so that the temperature does not exceed 22 ° C. For the third batch, 261 g of chromium and 31 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 90-101 g with stirring and cooling so that the temperature did not exceed 23 ° C. For the fourth batch, 526 g of chromium and 16 ml of DMP were added to the mixing tank and then this mixture was added to the reactor in increments of 30-108 g with stirring and cooling so that the temperature did not exceed 23 ° C. To the mixing vessel TEA / DEAC, 327 g of pure TEA and 256 g of pure DEAC were added. 261 g of the chromium solution was added to the chrome / DMP mixing tank. 78 ml of DMP was added to a separate cylinder connected to the reactor. The pressure of the reactor it is increased with nitrogen and the valves that connect each one of the cylinders before the reactor open. Reducing the pressure of the reactor to transfer the contents of each of these containers simultaneously to the reactor while the reactor is stirred and cooled. An increase of 1 ° C (20 ° C to 21 ° C) was observed in the reactor temperature in the addition of catalyst components. Ethylbenzene 181.44 g (0.4 Ib) was added to the chromium solution cylinder and used to rinse the chrome / DMP mixing tank. The ethylbenzene rinse was then added to the reactor. Ethylbenzene 226.8 g was added (0.5 Ib) the DMP cylinder. This rinse of the DMP cylinder was added to the reactor. Ethylbenzene 90.72 g (0.2 Ib) was added to the aluminum alkyl mixing vessel and then pressure in the reactor. The reactor was stirred for an additional 30 minutes. After standing overnight, it was filtered to the catalyst solution, using a filter as described above. The catalyst solution was tested for activity in a continuous 1 1 reactor. The results are shown as Catalyst 25 in Table 9. The results shown are the average of three separate tests run.

Table 9 Catalysts 21-24 show that varying the ratio of chromium to pyrrole in a disinventive manner, produces a catalyst which has increased selectivity, product purity and productivity. The catalyst 25 demonstrates that the separate simultaneous addition of the catalyst components to an active catalyst residue.

Example 12 Two catalysts, catalyst 26 and catalyst 27, were prepared with the addition of a nitrogen compound to the alkylaluminum compound to solubilize products resulting from the reaction of water and aluminum alkyls. Catalyst 26: To a dry 100 ml volumetric flask were added 25.01 g of ethylbenzene, 12.07 g of pure triethylaluminum (TEA) and 9.27 g of pure diethylaluminum chloride (DEAC) and 0.34 g of tributylamine. To this was added a solution containing 4.61 g of chromium (III) 2-ethylhexanoate, 2.27 g of ethylbenzene and 2.74 g of 2,5-dimethylpyrrole. Ethylbenzene was then added to provide a total volume of 100 ml. After standing overnight, no film was observed in the neck of the flask and no precipitate was observed. When the amine was not added to the catalyst preparation, a film was observed after standing overnight. A film was observed in the neck of the flask after standing for an additional 24 hours. This catalyst was tested to determine the activity in a 1 1 continuous reactor. The results of the two separate runs performed are shown in Table 10 below, as the catalyst 26. Catalyst 27: To a dry 100 ml volumetric flask, the They added 25.01 g of ethylbenzene, 12.07 g of pure triethylaluminum (TEA) and 9.27 g of pure diethylaluminum (DEAC) and 0.34 g of tributylamine. To this was added a solution containing 4.61 g of chromium (III) 2-ethylhexanoate, 2.27 g of ethylbenzene, 2.74 g of 2,5-dimethylpyrrole and 1.06 g of tributylamine. Ethylbenzene was then added to provide a total volume of 100 ml. After standing overnight, no film was observed in the neck of the flask and no precipitate was observed. When the amine was not added to the catalyst preparation, a film was observed after standing overnight. A film was observed in the neck of the flask after standing for an additional 24 hours. This catalyst was tested to determine the activity in a 1 1 continuous reactor. The results of the two separate tests performed are shown in Table 10 below, as catalyst 27.

Table 10 The example shows that the addition of an amine to the alkylaluminum compounds inhibits the formation of harmful precipitation from the catalyst solution.

Example 13 Catalyst 28: 2-ethylhexanoate chromium (III) (18.44 g) dissolved in 9.1 g of ethylbenzene, produces a viscous solution. When 2, 5-dimethylpyrrole (10.96 g) is added to this viscous solution, a much thinner solution results. This thinner solution is much more acceptable for water removal by molecular sieves. The activated 3A molecular sieves (15.05 g) are added to the chromium / pyrrole / ethylbenzene solution and allowed to stand with periodic shaking for 22 days before the catalyst is prepared. A solution was prepared in a 100 ml volumetric flask consisting of ethylbenzene (25.00 g), pure triethylaluminum (12.07 g) and pure diethylaluminum chloride (9.26 g). To this aluminum alkyl solution, 9.62 g of the dry chromium / pyrrole / ethylbenzene solution are added, and the resulting catalyst is diluted to 100 ml with additional ethylbenzene. After standing overnight, a film was observed in the neck of the flask, but no precipitate was observed in the flask. This catalyst was tested in a continuous 1 liter reactor and an average of two separate runs performed are shown in Table 11 as Catalyst 28. A control using a non-dried chromium / pyrrole / ethylbenzene solution was made at the same time. After resting overnight, a film was observed in the neck of the flask and a precipitate was also observed. This catalyst was tested in a continuous 1 liter reactor and an average of two separate runs performed are shown in Table 11 as Catalyst 29.

Table 11 In addition to the improved catalyst productivity as shown, reduced downstream corrosion could be obtained using the dry catalyst components.

Example 14 Catalysts 30-31: Chromium (III) 2-ethylhexanoate (222.10 g) was added to a ball flask equipped with a Dean-Stark tube. Ethylbenzene (147.39 g) was added and the flask heated to reflux the contents. Reflux was continued until no more water accumulated in the Dean-Stark tube. Ethylbenzene and water (27.13 g) were discharged from the Dean-Stark tube. This chromium solution was used to make the catalyst by adding it to a 100 ml volumetric flask containing ethylbenzene (16.73 g), pure triethylaluminum (12.28 g), pure diethylaluminum chloride (9.26 g) and 2,5-dimethylpyrrole (2.74 g). Ethylbenzene was subsequently added to dilute the catalyst to a volume of 100 ml. This catalyst was tested in a 1 1 continuous reactor. The results of the test (two catalyst preparations and three separate tests performed) are shown in Table 12 as Catalyst 30. A control catalyst was prepared in a similar manner, but used with chromium (III) 2-ethylhexanoate that has not been azeotropically dried. The results of the non-dry preparation tests are shown as Catalysts 31 in Table 12.

Table 12 The example shows that drying the chromium component by azeotropic distillation, preparing an effective catalyst and also reducing the corrosion of the equipment.

Example 15 An ethylene trimerization catalyst composition was prepared, using methods known per se. those skilled in the art, placed in a catalyst feed tank (under inert conditions) of a continuous production process of 1-hexene, and aged for approximately 900 hours. The continuous production process of 1-hexene was then started using the aged catalyst in the feed tank for the trimerization of ethylene to 1-hexene. Periodically, additional, fresh ethylene trimerization catalyst was prepared and added to the catalyst used in the continuous production process of 1-hexene. The average age of the ethylene oligomerization catalyst composition was periodically calculated to determine the average time that the catalyst has resided in the catalyst feed tank, based on the average catalyst composition in the catalyst feed tank. Through the continuous production process of 1-hexene, the product samples from the continuous production process of 1-hexene were removed and analyzed to determine the content of 1-hexene. Figure 5 shows the impact of the average residence time of the catalyst (i.e. age of the catalyst) on the purity of the hexene production produced by the continuous 1-hexene production process. Figure 5 indicates that the purity of the 1-hexene product is negatively impacted by increasing the age of the ethylene trimerization catalyst.

Claims

NOVELTY OF THE INVENTION Having described the present is considered as a novelty, and therefore, it is claimed as property contained in the following: CLAIMS

1. A method for making a catalyst for use in an oligomerization of an olefin, comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, characterized in that the method comprises in contact is a composition comprising the chromium-containing compound and a composition comprising the alkyl metal, wherein the composition comprising the chromium-containing compound is added to the composition comprising the alkyl metal.

The method according to claim 1, characterized in that the composition comprising the chromium-containing compound, comprises the pyrrole-containing compound, a non-metallic halide-containing compound, the solvent, or combinations thereof.

3. The method according to claim 2, characterized in that the composition comprising the Chromium-containing compound, comprises a non-halide alkyl metal in an amount of less than about 30 weight percent of the total weight of the chromium-containing compound in the catalyst.

4. The method of compliance with the claim 3, characterized in that the non-halide alkyl metal comprises trialkylaluminium.

5. The method of compliance with the claim 4, characterized in that the trialkylaluminum is triethylaluminum.

6. The method of compliance with the claim 1, characterized in that the composition comprising the alkyl metal, comprises the pyrrole-containing compound, the halide-containing compound, the solvent, or combinations thereof.

7. The method of compliance with the claim 2, characterized in that the composition comprising the alkyl metal, comprises the pyrrole-containing compound, the halide-containing compound, the solvent, or combinations thereof.

The method according to claim 1, characterized in that the composition comprises alkyl metal, an alkyl metal halide, a non-halide alkyl metal, a metal halide, or combinations thereof.

9. The method of compliance with the claim 1, characterized in that the composition comprising alkyl metal comprises diethylaluminum chloride (DEAC) and triethylaluminum (TEA).

The method according to claim 1, characterized in that the alkyl metal is the halide-containing compound.

The method "according to claim 10, characterized in that the halide-containing compound and the alkyl metal is diethylaluminum chloride (DEAC) 12.

The method according to claim 1, characterized in that it also comprises forming a mixture. of pyrrole-chromium, contacting the composition comprising a pyrrole-containing compound and the composition comprising the chromium-containing compound 13.

The method according to claim 12, characterized in that the composition comprising the pyrrole-containing compound. and the composition comprising the chromium-containing compound are contacted at an approximate molar ratio of pyrrole: Cr to form the pyrrole-chrome mixture 14.

The method according to claim 12, characterized in that the composition comprising the pyrrole-containing compound and the composition which comprises the chromium-containing compound, are contacted at a variable molar ratio of pyrrole: Cr, to form the pyrrole-chromium mixture.

The method according to claim 13, characterized in that the pyrrole-chromium mixture is added to the alkyl metal at an approximately constant molar ratio of pyrrole: Cr.

The method according to claim 14, characterized in that the pyrrole-chromium mixture is added to the alkyl metal at an approximately constant molar ratio of pyrrole: Cr.

17. The method according to claim 14, characterized in that the pyrrole-chromium mixture is added to the alkyl metal at an approximately variable molar ratio of pyrrole: Cr.

18. The method according to claim 1, further comprising forming a pyrrole-alkyl metal mixture comprising contacting the composition comprising the pyrrole-containing compound with the composition comprising the alkyl metal.

19. The method according to claim 1, characterized in that it further comprises, contacting simultaneously for a period of time, a composition comprising the compound that contains pyrrole and the composition comprising the chromium-containing compound, with the composition comprising the alkyl metal.

The method according to claim 1, characterized in that the final molar ratio of pyrrole: Cr of the catalyst is in a range from about 1.0: 1 to about 4.0: 1.

The method according to claim 1, characterized in that the final molar ratio of pyrrole: Cr of the catalyst is in a range from about 1.5: 1 to about 2.5: 1.

22. The method according to claim 1, characterized in that the final molar ratio of pyrrole: Cr of the catalyst is in a range from about 2.9: 1 to about 3.1: 1.

The method according to claim 19, characterized in that the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound are added to the composition comprising the alkyl metal at a molar ratio of pyrrole: Cr which is approximately constant during the period of time.

24. The method according to claim 23, characterized in that the molar ratio of pyrrole: Cr, is in the range from about

1. 0: 1 to approximately 4.0: 1. The method according to claim 19, characterized in that the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound are added to the composition comprising the alkyl metal at a molar ratio of pyrrole: Cr, which is approximately variable during the period of time.

26. The method according to claim 17, characterized in that the variable ratio of pyrrole: Cr, is approximately decreasing.

The method according to claim 25, characterized in that the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound are added to the alkyl metal at a molar ratio of pyrrole: Cr, which is approximately decreasing during the period of time.

The method according to claim 26, characterized in that: (i) an initial molar ratio of pyrrole: Cr at the start of the addition, is greater than the final molar ratio of pyrrole: Cr of the catalyst; and (ii) a final molar ratio of pyrrole: Cr at the end of the addition is less than the final molar ratio of pyrrole: Cr of the catalyst.

29. The method according to claim 27, characterized in that: (i) an initial molar ratio of pyrrole: Cr at the start of the addition is greater than the final molar ratio of pyrrole: Cr of the catalyst; and (ii) a final molar ratio of pyrrole: Cr at the end of the addition is less than the final molar ratio of pyrrole: Cr of the catalyst.

30. The method according to claim 28, characterized in that the final molar ratio of pyrrole: Cr of the catalyst is in the range from about 1.0: 1 to about 4.0: 1.

The method according to claim 28, characterized in that the initial molar ratio of pyrrole: Cr, is greater than about 6: 1 and the final molar ratio of pyrrole: Cr is greater than or equal to about 0.

32. The method according to claim 29, characterized in that the final molar ratio of pyrrole: Cr of the catalyst is in the range from about 1.0: 1 to about 4.0: 1.

The method according to claim 29, characterized in that the initial molar ratio of pyrrole: Cr, is greater than about 6: 1 and the final molar ratio of pyrrole: Cr is greater than or equal to about 0.

34. The method according to claim 28, characterized in that: (i) the initial molar ratio of pyrrole: Cr is about twice the final ratio of pyrrole: Cr of the catalyst for about a first half of the addition; and (ii) the final molar ratio of pyrrole: Cr is about 0 for about a second half of the addition.

35. The method according to claim 29, characterized in that: (i) the initial molar ratio of pyrrole: Cr is approximately twice the final ratio of pyrrole: Cr of the catalyst for about a first half of the addition; and (ii) the final molar ratio of pyrrole: Cr is about 0 for about a second half of the addition.

36. A method for making a catalyst for use in an oligomerization of an olefin, comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, characterized in that the includes reducing the precipitate by contacting a compound containing nitrogen with an alkyl metal before contacting the alkyl metal with a chromium-containing compound, the pyrrole-containing compound, the non-metallic halide-containing compound, the solvent, or combinations thereof.

37. The method according to claim 36, characterized in that the composition comprising nitrogen, is selected from the group consisting of amines, pyrroles, pyridines, substituted pyrroles such as indoles, di and tri-heterocyclic nitrogens, or combinations thereof .

38. The method according to claim 36, characterized in that the nitrogen-containing compound comprises 2,5-dimethylpyrrole.

39. The method according to claim 38, characterized in that the nitrogen-containing compound comprises tributylamine.

40. The method according to claim 36, characterized in that the final catalyst product is comprised of a molar ratio of from about 0.001 to about 10 moles of nitrogen to metal.

41. A method for making a catalyst for use in the oligomerization of an olefin, characterized in that it comprises contacting the pyrrolid compound dimeric, with a chromium-containing compound, an alkyl metal, a halide-containing compound, a hydrocarbon solvent, or combinations thereof.

42. The method according to claim 41, characterized in that the dimeric pyrrole comprises: Structure 1 Structure I Structure III or combinations thereof, wherein, each R1-R6 can independently be H, or an aromatic group C? ~ C2o, or any of the two adjacent to each other, taken together with the carbon atom to which they are attached, can form an aromatic or non-aromatic ring. Y is a structural bridge having 1 to 20 carbon atoms and includes linear, branched or paraffinic cyclic or aromatic structures or contains cyclic or aromatic paraffinic and includes heteroatoms such as oxygen or sulfur in the form of linear, branched functionalities or cyclic ether, Silyl, sulfur, sulfone, sulfoxide.

43. The method according to claim 41, characterized in that in the structure (I) R1, R3, R4 and R6 are a methyl group, R2 and R5 are hydrogens, and Y = (CH2) n where n = l-10.

44. The method according to claim 41, characterized in that in the structure (II), R1 and R6 are methyl groups, R2-R5 are hydrogens, and Y = (CH2) n where n = l-10.

45. The method according to claim 41, characterized in that in the structure (III), R1, R3 and R5 are methyl groups, R2, R4 and R6 are hydrogen, and Y = (CH2) n where n = l- 10

46. A method for making a catalyst for use in the oligomerization of an olefin, characterized in that it comprises a compound containing chromium, a compound containing pyrrole, an alkyl metal, and a halide-containing compound, comprising contacting the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, or combinations thereof with an oligomerization catalyst composition previously prepared.

47. The method according to claim 46, characterized in that the chromium-containing compound, the pyrrole-containing compound, the alkyl metal, and the halide-containing compound are simultaneously contacted with a previously prepared oligomerization catalyst composition.

48. The method according to claim 46, characterized in that the oligomerization catalyst prepared previously comprises the same or different chromium-containing compound, pyrrole-containing compound, alkyl metal and halide-containing compound.

49. A method for making a catalyst for use in the oligomerization of an olefin, characterized in that it comprises contacting a chromium-containing compound, a pyrrole-containing compound, and an alkyl metal, with a previously prepared oligomerization catalyst composition.

50. The method according to claim 49, characterized in that it also comprises contacting a halide-containing compound with the previously prepared oligomerization catalyst composition.

51. The method according to claim 50, characterized in that the halide-containing compound comprises a metal halide, an alkyl metal halide, or combinations thereof.

52. The method according to claim 49, characterized in that said contacting is carried out in a holding tank to feed the catalyst to a reactor.

53. The method according to claim 46, characterized in that said method for making the catalyst is carried out at a temperature of less than about 120 ° C.

54. The method according to claim 49, characterized in that said method for making the catalyst is carried out at a temperature of less than about 120 ° C.

55. A method for olefin oligomerization characterized in that it comprises: (a) preparing a catalyst by combining a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent; Y (b) contacting the catalyst with the olefin within about 1000 hours of catalyst preparation.

56. An ethylene trimerization catalyst, characterized in that it comprises a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, wherein the 1-hexene produced by the catalyst, it has a purity of at least about 98.8 at a time within about 800 hours after catalyst preparation.

57. A method for making a catalyst for use in an oligomerization of an olefin, comprising a chromium-containing compound, a pyrrole-containing compound, an alkyl metal, a halide-containing compound, and optionally a solvent, characterized in that the comprises reducing all or a portion of water, acidic protons or both, from a composition comprising the chromium-containing compound, a composition comprising the pyrrole-containing compound, a composition comprising a non-metallic halide-containing compound, a composition comprising the solvent, or combinations thereof, prior to contact thereof with a composition comprising a metal halide-containing compound.

58. The method according to claim 57, characterized in that the composition comprising a metal halide-containing compound, comprises (i) an alkyl metal halide, (ii) a metal halide and a metal alkyl, (iii) a non-metallic halide and an alkyl metal, or (iv) combinations thereof.

59. The method according to claim 57, characterized in that it further comprises the use of a catalyst comprising reduced components that provide less than one or more corrosive compounds than the use of the same catalyst without reduced components.

60. The method according to claim 57, characterized in that the reduction of all or a portion of water, acidic protons or both, further comprises contacting one or more compositions comprising water, acidic protons or both, and an alkyl metal not halide prior to contact thereof with the composition comprising the metal halide containing compound.

61. The method according to claim 60, characterized in that the non-halide alkyl metal comprises triethylaluminum (TEA).

62. The method according to claim 60, characterized in that the portion of the non-halide alkyl metal is an effective amount for substantially reducing all available water, acidic protons or both, from the compositions put in contact with the non-halide alkyl metal.

63. The method according to claim 60, characterized in that the acidic protons are provided by 2-ethylhexanoic acid.

64. The method according to claim 60, characterized in that the non-halide alkyl metal is added in an amount of less than or equal to about 30 weight percent of the total weight of the compositions contacted.

65. The method according to claim 60, characterized in that the reduction of all or a portion of water, acidic protons or both, further comprises forming a mixture by contacting the composition comprising the chromium-containing compound and the non-alkyl metal. halide prior to contacting the mixture with the remaining compositions.

66. The method according to claim 65, characterized in that the non-halide alkyl metal is added to the composition comprising the chromium-containing compound, to form the mixture.

67. The method according to claim 65, characterized in that the non-halide alkyl metal is added in an amount such that the molar ratio of non-halide alkyl metal to chromium-containing compound in the mixture is less than about 1: 1.

68. The method according to claim 65, characterized in that the non-halide alkyl metal is added in an amount sufficient to reduce at least about 25 percent of the water, acidic protons or both.

69. The method according to claim 65, characterized in that the non-halide alkyl metal is added in an amount which is approximately an excess of 200 percent of an amount sufficient to reduce at least about 100 percent of the water, acidic protons. or both.

70. The method according to claim 65, characterized in that it further comprises filtering a precipitate to form the mixture before combining the mixture with the composition comprising the pyrrole-containing compound, the composition comprising the halide-containing compound, the composition comprising the solvent, any remaining non-halide alkyl metal, or combinations thereof.

71. The method according to claim 65, characterized in that it further comprises contacting the composition comprising the compound containing pyrrole with the composition comprising the chromium-containing compound, before contacting said composition comprising the chromium-containing compound, with the non-halide alkyl metal.

72. The method according to claim 71, characterized in that the non-halide alkyl metal is added to the combination of the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound.

73. The method according to claim 60, characterized in that the reduction of all or a portion of water, acidic protons or both, further comprises contacting the composition comprising the pyrrole-containing compound with all or a portion of metal non-halide alkyl to form a mixture, before contacting the mixture with the remaining compositions.

74. The method according to claim 65, characterized in that the reduction of all or a portion of water, acidic protons or both, further comprises contacting the composition comprising the pyrrole-containing compound with all or a portion of metal alkyl non-halide to form a second mixture, before contacting the second mixture with the remaining compositions.

75. The method according to claim 60, characterized in that the contact further comprises: (a) contacting the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound; (b) contacting the resulting contacted compounds, from step (a) and the non-halide alkyl metal; and (c) contacting the resulting contacted compounds of step (b) and the composition comprising the metal halide-containing compound.

76. The method according to claim 75, characterized in that it further comprises contacting the non-metallic halide with (i) the composition comprising the chromium-containing compound before step (a), (ii) the composition comprising the pyrrole-containing compound before step (a), (iii) both the composition comprising the chromium-containing compound and the composition comprising the pyrrole-containing compound before step (a); or (iv) the compounds contacted resulting from step (a).

77. The method according to claim 60, characterized in that: (a) the composition comprising the chromium-containing compound and a portion of the non-halide alkyl metal are contacted to form a first mixture; (b) the composition comprising the pyrrole-containing compound and a portion of the non-halide alkyl metal are contacted to form a second mixture; and (c) the first mixture and the second mixture are contacted with the composition comprising the metal halide containing compound.

78. The method according to claim 77, characterized in that step (c) is carried out over a period of time, an initial molar ratio of pyrrole: Cr at the beginning of the time period is greater than the final molar ratio of pyrrole: Cr of the catalyst, and a final molar ratio of pyrrole: Cr at the end of the time period is less than the final molar ratio of pyrrole: Cr of the catalyst.

79. A process for preparing a chromium-based catalyst, characterized in that it comprises carrying a pyrrole ring-containing compound, an aluminum alkyl compound, and a halogen-containing compound, in contact with each other in a hydrocarbon solvent, halogenated hydrocarbon solvent or mixture thereof, and then bringing the resulting mixed solution into contact with the chromium compound, wherein water, acidic protons or both are reduced from the catalyst or a component thereof, before or during the preparation of the catalyst.

80. A process for preparing a chromium-based catalyst, characterized in that it comprises carrying a chromium compound, a pyrrole ring-containing compound, an aluminum alkyl compound, and a halogen-containing compound, in contact with each other in a hydrocarbon solvent , halogenated hydrocarbon solvent or mixture thereof, in the absence of an alpha-olefin under such conditions, such that the concentration of the chromium compound in the resulting mixed solution is approximately lxlO-7 to 1 mol / liter, where water, acidic protons or both, are reduced from the catalyst or a component thereof, before or during the preparation of the catalyst.

81. A process for treating a catalyst component, characterized in that it comprises reducing water, acidic protons or both, of a catalyst component comprising a pyrrole derivative represented by the general formula (I): 0) wherein R1 to R4 are a hydrogen atom or a linear or branched hydrocarbon group having 1 to 20 carbon atoms, in which R3 and R4 can integrally form a ring; X is a halogen atom; M is an element selected from the group consisting of those belonging to Group 3, Group 4, Group 6 (exclusive of chromium), Group 13, Group 14 and Group 15 of the Periodic Table; and n are numbers that satisfy the relations of l = m = d, 0 = n = 5 and 2 = m + n < 6, with the proviso that the sum of m and n is identical to the valence of the element M; n represents the number of Rs; and R is a hydrogen atom or a straight or branched hydrocarbon group having 1 to 20 carbon atoms and when n is not less than 2, and Rs may be the same or different.

82. A catalyst for ethylene trimerization, characterized in that it comprises: (i) an organometallic complex having a neutral multidentate ligand having a tripoid structure, represented by the following formula (1): AMQn (1) wherein A can be a neutralized multidentate ligand having a tripoid structure, M can be a transition metal atom of group 3 to group 10 of the periodic table, each Q can be independently selected from the group consisting of one atom of hydrogen, a halogen atom, a straight or branched chain alkyl group having from 1 to 10 carbon atoms, which may have a substituent, an aryl group having 6 to 10 carbon atoms, which may have a substituent , and n is an integer equal to a valence of formal oxidation of M, and (iv) an alkylaluminioxane; said neutralized multidentate ligand A in the formula (1) is a tridentate ligand represented by the following formula (2) or of the formula (3): (2) D1- - J- OI1- 1 OmL-L1 where j, k and m, independently represent an integer from 0 to 6, each D1 independently represents a divalent hydrocarbon group, which may have a substituent, each L1 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L1 are not concurrently a substituent containing an element of group 14 or 17, G1 represents a carbon or silicon atom, and R1 represents a hydrogen atom, an alkyl group which has 1 to 10 carbon atoms, which may have a substituent, or an aryl group having 6 to 10 carbon atoms, which may have a substituent; (3) wherein a, b and c independently represent an integer from 0 to 6; u represents an integer of 0 or 1; each D2 independently represents a divalent hydrocarbon group, which may have a substituent; each L2 independently represents a substituent containing an element of group 14, 15, 16 or 17 of the periodic table, with the proviso that the three L2 are not concurrently a substituent containing an element of group 14 or 17, G2 represents a nitrogen or phosphorus atom, when u is 0, or a phosphorus atom when u is 1, and R2 represents an oxygen or sulfur atom. Water, acidic protons or both, can be reduced from the catalyst or a component thereof, before or during the preparation of the catalyst.

83. The catalyst according to claim 82, characterized in that it also comprises a halogenated inorganic compound.

84. The catalyst according to claim 83, characterized in that it also comprises a compound containing an alkyl group, represented by the following formula (4): RpEJq (4) where p and q are numbers that satisfy the formulas: 0 < p = 3 and 0 = q < 3, provided that (P + q) is in the range of 1 to 3, E represents an atom, other than a hydrogen atom of group 1, 2, 3, 11, 12 or 13 of the periodic table, each R represents independently an alkyl group having 1 to 10 carbon atoms, and each J independently represents a hydrogen atom, an alkoxide group having 1 to 10 carbon atoms, an aryloxy group having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or a halogen atom.

85. The catalyst according to claim 82, characterized in that it further comprises a compound containing an alkyl group, represented by the following formula (4): RpEJq (4) wherein p and q are numbers satisfying the formulas: 0 <p = 3 and 0 = q < 3, provided that (P + q) is in the range of 1 to 3, E represents an atom, other than a hydrogen atom of group 1, 2, 3, 11, 12 or 13 of the periodic table, each R represents independently an alkyl group having 1 to 10 carbon atoms, and each J independently represents a hydrogen atom, an alkoxide group having 1 to 10 carbon atoms, a group aryloxy having 6 to 10 carbon atoms, an aryl group having 6 to 10 carbon atoms or a halogen atom.

86. The catalyst according to claim 82, characterized in that it also comprises at least one compound selected from the group consisting of an amine compound and an amide compound.

87. A catalyst system for oligomerization of olefins, characterized in that the system includes: a source of chromium metal alkyl; and a halopyrrole ligand, wherein water, acidic protons or both, are reduced from the catalyst system or a component thereof, before or during catalyst formation.

88. A method for producing 1-hexene, characterized in that it includes at least the step of trimerizing ethylene using a catalyst system, comprising a combination of at least one source of chromium, an alkyl metal and a halopyrrole ligand, wherein water , acidic protons or both, are reduced from the catalyst system or a component thereof, before or during the formation of the catalyst.

89. A multidentate mixed heteroatomic ligand for an oligomerization of olefin catalysts, characterized in that the ligand includes at least three heteroatoms of which at least one is a sulfur atom, wherein water or acidic protons or both, are reduced from the catalyst system or a catalyst component.

90. A ligand as claimed in claim 89, characterized in that water or acidic protons or both, are reduced in the ligand and the ligand is selected from the following types: (a) R <R> R3) (R4CRS) in where R1, R3 and R5 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R4 may be the same or different and are hydrocarbyls of Ci up to about C5; A is nitrogen or phosphorus; and B and C are sulfur; and (b) R ^ A ^ BR) (R5CR6) wherein R1, R31, R4 and R6 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy , aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R5 may be the same or different and are hydrocarbyls of Ci up to about L5; A and B are individually nitrogen or phosphorus; and C is sulfur; and (c) A (RXBR2R3) (RCR5) wherein R2, R3 and R5 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino , dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R1 and R4 may be the same or different and are hydrocarbyls of Cz up to about C5; B is nitrogen or phosphorus; and A and C are sulfur; and (d) A ^ BR ^ 3) (R4CR5R6) wherein R2, R3, R5 and R6 can be hydrogen or independently selected from the groups consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy , aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R1 and R4 may be the same or different and are hydrocarbyls of Ci up to about C5; B and C are individually nitrogen or phosphorus; and A is sulfur.

91. A mixed heteroatomic ligand for oligomerization of olefin catalysts, characterized in that the ligand includes at least three heteroatoms, of which at least one hetero atom is nitrogen and at least two heteroatoms are not the same, wherein water, acidic protons or both are reduced from the catalyst system or a catalyst component.

92. A ligand as claimed in claim 91, characterized in that water or acidic protons or both are reduced in the ligand and the ligand has the structure R ^^ BR ^ 4) (R5CR6R7) wherein R1, R3, R4 , R6 and R7 can be hydrogen or independently selected from the group consisting of alkyl, aryl, aryloxy, halogen, nitro, alkoxycarbonyl, carbonyloxy, alkoxy, aminocarbonyl, carbonylamino, dialkylamino or derivatives thereof, or aryl substituted with any of these substituents; R2 and R5 are the same or different and are hydrocarbyls of Ci up to about C15; and at least A, B or C is nitrogen with the remainder of A, B and C being individually nitrogen or phosphorus.

93. The method according to claim 57, characterized in that all or a portion of water is removed from the chromium-containing compound before contact with the metallic halide-containing compound.

94. The method according to claim 57, characterized in that all or a portion of the water is removed from the chromium-containing compound, before contact with the alkyl metal-containing compound.

95. The method according to claim 93, characterized in that the compound that contains chromium is contacted with a solvent to form a solution and the solution is subjected to azeotropic distillation.

96. The method according to claim 95, characterized in that the solvent comprises an aromatic compound, halogenated compound, a paraffin, or combinations thereof.

97. The method according to claim 96, characterized in that the aromatic compound comprises benzene, toluene, ethylbenzene, mixed xylenes, ortho-xylene, meta-xylene, para-xylene or combinations thereof.

98. The method according to claim 95, characterized in that the amount of water removed is monitored by infrared analysis or other known methods used to determine the water content.

99. The method according to claim 57, characterized in that one or more catalyst components other than (i) a composition comprising an alkyl metal halide, (ii) a composition comprising a metal halide and an alkyl metal, ( iii) a composition comprising a non-metallic halide and an alkyl metal, or (iv) combinations thereof, are contacted with an adsorbent for remove water

100. The method according to claim 57, characterized in that the chromium-containing compound, the pyrrole-containing compound, and the non-metallic halide-containing compound, the solvent, or combinations thereof, are contacted with an adsorbent to remove water.

101. The method according to claim 100, characterized in that the adsorbent comprises a 3-Angstrom molecular sieve, a 5-Angstrom molecular sieve, alumina, silica or combinations thereof.

102. A method for making a catalyst composition for use in the oligomerization of an olefin, comprising a chromium-containing compound, characterized in that the method comprises reducing all or a portion of water, acidic protons or both, of a composition comprising the compound that contains chromium.

103. The method according to claim 102, characterized in that the chromium-containing compound is contacted with a non-halide alkyl metal.

104. The method according to claim 103, characterized in that the non-halide alkyl metal is triethylaluminum.

105. The method according to claim 102, characterized in that the chromium-containing compound is contacted with a solvent, to form a solution and the solution is subjected to azeotropic distillation.

106. The method according to claim 105, characterized in that the solvent comprises an aromatic compound, a halogenated compound, a paraffin, or combinations thereof.

107. The method according to claim 105, characterized in that the solvent is an aromatic compound comprising benzene, toluene, ethylbenzene, mixed xylenes, ortho-xylene, meta-xylene, para-xylene or combinations thereof.

108. The method according to claim 102, characterized in that the chromium-containing compound is contacted with an adsorbent to remove water.

109. The method according to claim 108, characterized in that the adsorbent comprises 3-Angstrom molecular sieves, 5-Angstrom molecular sieves, alumina, silica, or combinations thereof.