MXPA02005399A - Processes for preventing generation of hydrogen halides in an oligomerization product recovery system. - Google Patents

Abstract

The invention is an oligomerization process. A catalyst, a lower olefin, and a process medium are provided. The lower olefin is reacted in the presence of the catalyst to produce a product stream comprising a higher olefin product and a catalyst residue dispoersed in the process medium. The resulting product stream is treated with a quenching material. The quenching material can be an aliphatic primary amine, an aliphatic secondary amine, an alcohol, or a combination of those materials. Amine quenching materials have been found to generate few or no hydrogen halides when used to quench oligomerization catalysts. Alcohol quenching materials can generate hydrogen halides in use. This problem can be alleviated by treating the product stream with a stabilizing material that forms a stable hydrogen halide salt. Exemplary stabilizing materials include aliphatic amines, aromatic amines, and metal salts of amides, butoxides, or carboxylic acids.

Description

PROCESSES TO PREVENT THE GENERATION OF HYDROGEN HALURES IN AN OLIGOMERIZATION PRODUCT RECOVERY SYSTEM BACKGROUND OF THE INVENTION This invention is generally concerned with the catalytic production of olefins. This invention is more specifically concerned with a process for quenching the catalyst in the effluent of an oligomerization reactor, such as a trimerization reactor, to avoid generation of hydrogen halides. Olefins, in particular alpha-olefins, also referred to as 1-olefins, have many uses as specific chemical compounds and as monomers or comonomers in polymerization processes. Higher olefins and other olefins can be produced by contacting the lower olefins, for example ethylene with a catalyst, to produce mono-olefin trimers, diolefin dimers and other reaction products in an addition reaction. This reaction can be referred to as * trimerization "u * oligomerization". Frequently, the catalyst system is dispersed in a process solvent and the reactants, a lower 1-olefin and optionally hydrogen, are fed as gases. The reaction product and higher olefins are dissolved in the process solvent as they are formed. Ref .: 138415 The olefins of the product and spent catalyst system are recovered by separating the process solvent that contains them, that is, the effluent from the reactor, from the reactor. Preferably a catalyst deactivating agent is added to the reaction system before separation of any of the reaction components. The effluent can be treated to deactivate or deactivate the catalyst The effluent can be separated for the waste of the catalytic system, recycled from any remaining lower 1-olefin and consumed from the process solvent and olefins from the recovery product. The quenching agent can be used to quench the aluminum alkyl portion of the catalytic system The quenching of the catalytic system is important to prevent isomerization of the 1-olefin product to undesirable internal and higher 2-olefins that decrease the purity of the product. The catalytic system can also eliminate dangers associated with air and water sensitive aluminum alkyls Previous patents teach that an alcohol can be added to the catalyst discharge in the effluent of an olefin oligomerization reactor to quench or "deactivate" the Catalyst US Pat. No. 5,689,028 discloses the addition of 2-ethylhexanol to the effluent of the trimerization reactor as a shutdown agent to shut down the catalytic system. U.S. Patent No. 5,859,303, Example 1, discloses that the addition of an alcohol can quench or deactivate the catalyst system. US Pat. No. 5,750,817 discloses the use of ethanol to quench an ethylene trimerization reaction. U.S. Patent No. 5,750,816 teaches the addition of alcohols, phenols, carboxylic acids, primary or secondary amines or ammonia to the effluent of an ethylene trimerization reactor as a "metal solubilizing agent." The patent states, "the percentage of agent used metal solubilizer can be selected from a wide range of a trace amount to one equivalent of the solvent, but is preferably in a range of 0.001 to 501 by weight, more preferably 0.01 to 10 = by weight in terms of concentration in the solvent. "For example 0.022" by weight of 1-hexanol (Examples 5 and 13), hexylamine (Examples 6 and 14) or ammonia (Examples 7 and 15) is used. The patent teaches in general that this step "maintains [s] the dispersed state of mainly the catalytic components in the reaction dispersion" "in the process line from the exit of the oligomerization reactor to the entrance of the distillation tower". U.S. Patent No. 5,750,816, column 2, lines 20-23 and 49-67.

BRIEF DESCRIPTION OF THE INVENTION It has been discovered that alcohols, used as quenching agents to quench a catalytic halogenated oligomerization system, following an oligomerization reaction, can produce hydrogen halides. For example, shutting down a chlorinated catalyst with an alcohol, particularly in the presence of water or the bottoms of a kettle reactor found in a plant (which may contain ferrous chloride), can lead to the production of hydrogen chloride gas . Hydrogen halides can be highly corrosive to process equipment. Thus, it is desirable to provide catalyst paid materials and methods that do not produce hydrogen halides. Again it is desirable to reduce or eliminate the generation of hydrogen halides when alcohols are used as quenching agents. One or more of the preceding wishes or one or more other wishes which will become reality after consideration of the present specification, are satisfied in whole or in part by the invention described herein. One aspect of the invention is an oligomerization process. In the process a catalytic system, a lower olefin reagent and a process medium are provided. The lower olefin is reacted in the presence of the catalyst system to produce a product stream. The product stream includes a superior olefin product and catholic system residue, both dispersed in the solvent or process medium. The stream of the resulting product is treated with a paid material comprising a primary aliphatic amine, a secondary aliphatic amine or a combination of those materials. Optionally, an alcohol or other quenching materials can also be combined with the selected amine to form composite quenching materials. The quenched material is provided in an amount by at least least effective to extinguish the catalyst. It has been found that amine quenching materials generate little or no hydrogen halide when used to quench oligomerization catalysts. Another aspect of the invention is an oligomerization process in which the product stream is treated with an alcohol in an at least partially effective amount to quench the catalyst. The product stream is also treated with a stabilizing material that forms a stable hydrogen halide salt. The stabilizing material is provided in an amount effective to reduce at least the generation of free hydrogen halides.

Although it has been found that alcohol quench materials generate hydrogen halides, the stabilizer material alleviates the problem, apparently to interact with any hydrogen halide to produce a stable material (although the present invention is not limited to any particular mode of action) .

DETAILED DESCRIPTION OF THE INVENTION While the invention will be described in relation to one or more embodiments, it will be understood that the invention is not limited to those embodiments. On the contrary, the invention includes all alternatives, modifications and equivalents as may be included in the spirit and scope of the joint claims. The mention of or statements of a preference for certain modalities does not indicate an attempt to exclude other modalities that are not mentioned or claimed to be preferred. The reaction contemplated herein is broadly concerned with the oligomerization of ethylene and other lower olefins to produce higher olefins. In this "inferior" and "superior" context they are relative; a lower olefin, as used in this disclosure, is any 1-olefin that can be converted to a higher 1-olefin, wherein the higher 1-olefin has a greater number of carbon atoms than the lower olefin. The reaction is carried out in the presence of one or more catalysts under conditions that encourage the reaction to proceed. The present invention will be exemplified in the context of a trimerization reaction, although it is contemplated that the invention will find use in other oligomerization reactions. "Trimerization", as used in this disclosure, is defined as any combination of two, three, or more olefins that reduce the number of olefin, that is, carbon-carbon double bonds by two. For example, the three olefin bonds in the combination of three ethylene units can be reduced by two, to an olefin bond in 1-hexane. In another example, the four olefin linkages in the combination of two 1,3-butadiene units can be reduced by two, to two olefin bonds, in 1,5-cyclooctadiene. As used herein, the term "trimerization" is intended to include the dimerization of diolefins, also as "co-trimerization", as discussed further hereinbelow. The reactants, catalysts, equipment and processing conditions useful in the present process and the reaction products and by-products formed as a result of the trimerization reaction are hereinafter further described.

Applicable reagents for use in the trimerization process of this invention include olefinic compounds that can self-react, that is, trimerize, to give useful products. For example, the self-reaction of ethylene can give 1-hexene, and the self-reaction of 1,3-butadiene can give 1,5-cyclooctadiene. Reagents applicable for use in the trimerization process of this invention also include olefinic compounds that can react with other olefinic compounds, that is, co-trimerize to give useful products. For example, the co-trimerization of ethylene plus hexene can give 1-decene or 1-tetradecene. The co-trimerization of ethylene and 1-butene can give 1-octene. The co-trimerization of 1-decene and ethylene can give 1-tetradecene or 1-docosene. Trimerizable olefin compounds are those compounds having from about 2 to about 30 carbon atoms per molecule and having at least one olefinic double bond. Exemplary olefins include, but are not limited to the following. Acyclic olefins are contemplated such as, for example, ethylene, propylene, 1-butene, 2-butene, isobutylene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 1-heptene, 2-heptene , 3-heptene, the four normal octenes, the four normal nonenes and mixtures of any two or more of those.

Exemplary diolefin compounds contemplated herein include, but are not limited to, 1,3-butadiene, 1,4-pentadiene and 1,5-hexadiene. If branched or cyclic olefins are used as reagents, while not wishing to be limited by theory, it is believed that steric hindrance could impede the trimerization process. Accordingly, the branched or cyclic portion of the olefin will generally be distant from the carbon-carbon double bond. The present invention is not limited to use with the olefins suggested by this theory as useful. Any olefin that will participate in the reaction is contemplated for use in accordance with the present invention.

Catalytic Systems A trimerization catalyst system contemplated in accordance with this invention is the three-part system comprising the combination of a chromium source, a pyrrole-containing compound and an alkyl metal. Optionally, the catalyst system may be supported on an inorganic oxide support. These catalyst systems are especially useful for the dimerization and trimerization of olefins, such as for example ethylene to 1-hexene. For the present purposes, any catalyst or catalyst system comprising an alkyl metal is contemplated more broadly. The catalyst system commonly includes a halide source, for example, a chloride, bromide, iodide or fluoride compound. The source of chromium can be one or more organic, inorganic compounds, in which the oxidation state of chromium is from 0 to 6. In general, the chromium source will have a CrXr formula, in which each X can be the same or different and can be any organic or inorganic radical and n is an integer from 1 to 6. Exemplary organic radicals should have from about 1 to about 20 carbon atoms per radical and can be alkyl, alkoxy, ester, ketone, carboxylate radicals or amido, for example. The radicals can be straight or branched chain, cyclic or acyclic, aromatic or aliphatic, they can be made from mixed aliphatic, aromatic or cycloaliphatic groups. Exemplary inorganic radicals include but are not limited to any anion or oxidizing radical, for example, halides, sulfates or oxides. Preferably, the chromium source is a compound containing chromium (II) or chromium (III) which can produce a catalytic system with enhanced oligomerization or trimerization activity. More preferably, the source of chromium is a chromium (III) compound because of its ease of use, availability and activity of the improved catalyst system.

Exemplary chromium (III) compounds include, but are not limited to, chromium carboxylates, chromium naphthanates, chromium halides, chromium pyrrolides and dichromate dionates. Specific exemplary chromium (III) compounds (followed in some instances subsequently by their respective abbreviations) include, but are not limited to, chromium (III) - Cr (TMHD) 2, 2, 6,6-tetramethylheptadionate; 2-ethylhexanoate of Chromium (III) - Cr (EH); tris-2-ethylhexanoate) of chromium (III); Exponential naphthenate (III) -Cr (Np) 3; chromium chloride (III); chromic bromide; chromic fluoride; chromium acetylacetonate (III); chrome acetate (III); Chromium butyrate (III); chrome neopentanoate (III); chromium laurate (III); chromium stearate (III); chromium pyrrolide (III); chromium oxalate (III) or combinations of two or more. Specific exemplary chromium (II) compounds include, for example, but are not limited to chromium bromide; Chloride fluoride; chromium chloride; bis- (2-ethylhexanoate) of chromium (II); chromium acetate (HJ, chromium (II) butyrate, chrome (II) neopentanoate, chromium (II) laurate, chromium (II) stearate, chromium (II) oxalate, chromium (II) pyrrolide or combinations of two or more The chromium (II) and chromium (III) compounds can also be combined.

The pyrrole-containing compound of the catalyst system may be any one, two or more of those that will react with the chromium source to form a chromium pyrrolide complex. As used in this disclosure, the term "pyrrole-containing compound" refers to hydrogen pyrrolide (ie, pyrrole C "HN), derivatives of hydrogen pyrrolide and substituted pyrrolide, also as metal pyrrolide complexes and mixtures of the same. A "pyrrolide" is defined as a compound that contains a heterocycle containing 5-membered nitrogen. Broadly, the pyrrole-containing compound may be pyrrole or any heteroleptic or homolytic metal complex or salt containing a pyrrolide radical or ligand. The pyrrole-containing compound can be added either affirmatively to the reaction or generated in situ. In general, the pyrrole-containing compound will have from about 4 about 20 carbon atoms per molecule. Exemplary pyrrolides, mentioned due to their high reactivity and activity with other reagents, include pyrrole, lithium pyrrolide; sodium pyrrolide; potassium pyrrolide; cesium pyrrolide; the salts of substituted pyrrolides or combinations thereof. Useful substituted pyrrolides include, but are not limited to, pyrrole-carboxylic acid; 2-acetylpyrrole; pyrrole-2-carboxaldehyde; tetrahydroindole; 2,5-dimethylpyrrole; 2,4-dimethyl-3-ethylpyrrole; 3-acetyl-2, -dimethylpyrrole; ethyl-2,4-dimethyl-5- (ethoxycarbonyl) -3-pyrrole-propionate; ethyl-3, 5-dimethyl-2-pyrrolcarboxylate or combinations thereof. When the pyrrole-containing compound contains chromium, the resulting chromium compound can be called a chromium pyrrolide. The most preferred pyrrole-containing compounds useful in a trimerization catalyst system can be selected from the group consisting of hydrogen pyrrolide, 2,5-dimethylpyrrole or chromium pyrrolide because of the improved trimerization activity. Occasionally, for ease of use, a chromium pyrrolide can provide both the chromium source and the pyrrole-containing compound. As used in this disclosure, when a chromium pyrrolide is used to form a catalyst system, a chromium pyrrolide is considered to provide both the chromium source and the pyrrole-containing compound. While all pyrrole-containing compounds can produce catalyst systems with high activity and productivity, the use of pyrrole or 2,5-dimethylpyrrole can produce a catalyst system with improved activity and selectivity to a desired product.

The alkyl metal of the catalyst system may be any heteroleptic or homoleptic alkyl metal compound. One or more alkyl metals can be used. The alkyl ligands on the metal can be aliphatic, aromatic or both (if more than one ligand is present). Preferably, the alkyl levels can be any saturated or unsaturated aliphatic radical. The metal alkyl can have any number of carbon atoms. However, due to commercial availability and ease of use, the metal alkyl will usually comprise less than about 70 carbon atoms per alkyl metal molecule and preferably less than about 20 carbon atoms per molecule. Exemplary alkyl metals include, but are not limited to, aluminum alkyl compounds, alkyl boron compounds, alkylmagnesium compounds, alkylzinc compounds or "alkyl lithium compounds." Exemplary alkyl metals include, but are not limited to, n-butyl lithium.; s-butyllithium; t-butyllithium; diethylmagnesium; diethylzinc; triethylaluminium; trimethylaluminum, triisobutylaluminum or combinations thereof. Preferably, the metal alkyl is selected from the group consisting of non-hydrolyzed alkyl aluminum compounds, that is, not pre-contacted with water, derivatives of alkylaluminium compounds, halogenated alkylaluminium compounds and mixtures thereof. The mixed alkyl metals can provide selectivity to the improved product, also as improved catalytic system reactivity, or productivity. The use of hydrolyzed alkyl metals can result in decreased olefin production (ie, liquid) and increased polymer production (ie, solid). More preferably, the metal alkyl is a non-hydrolyzed aluminum alkyl compound expressed by the general formulas AIR3, AIR2X, AIRX ^, AIR2OR, AIRXOR or AI2R3X3, in which Al is an aluminum atom, each R is an alkyl group, O is an oxygen atom and X is a halogen atom. Exemplary compounds include, but are not limited to, triethylaluminum; tripropylaluminum; tributyl aluminum; diethylaluminum chloride; diethylaluminum bromide, diethylaluminum ethoxide; diethylaluminum phenoxide; ethylaluminum dichloride; ethylaluminum sesquichloride and mixtures thereof for a better activity of the catalyst system and product selectivity. The most preferred single aluminum alkyl compound is triethylaluminum, for the best activity of the catalyst system and selectivity of the product. The most pertinent catalyst systems with the present invention comprise alkylaluminiums containing a halide, such as a chloride or a bromide.

While not wishing to be bound by theory, it is believed that a chloride-containing compound can improve the purity and selectivity of the product. Any chloride-containing compound can be used, for example DEAC and organic chlorides. Exemplary organic organochlorides include, but are not limited to, carbon tetrachloride, methylene chloride, chloroform, benzyl chloride, 1-hexachloroethane, and mixtures thereof. A particular composite catalyst contemplated herein is the combination of chromium (III) ethylhexanoate, 2,5-dimethylpyrrole, triethylaluminum and diethylaluminum chloride. This composite catalyst system can be used to trimerize ethylene, forming 1-hexene. U.S. Patent No. 5,198,563 teach the use of an appropriate trimerization catalyst for the present invention. The entire patent is incorporated herein by its disclosure of trimerization catalysts.

Means Usually, the chromium source, pyrrole-containing compound and the metal alkyl are combined in an olefinic or aromatically unsaturated hydrocarbon reaction medium. The hydrocarbon can be any aromatic or aliphatic hydrocarbon, in the gaseous, liquid or solid state. Preferably, to fully contact the source of chromium, the compound containing pyrrole and alkyl metal, the hydrocarbon is in a liquid state. The hydrocarbon can have any number of carbon atoms per molecule. Usually, the hydrocarbon will comprise less than about 70 carbon atoms per molecule and preferably less than about 20 carbon atoms per molecule, due to the commercial availability and ease of use of low molecular weight compounds. The most-referred hydrocarbon compound is a reaction product formed by the use of the catalyst system. For example, if 1-hexene is a reaction product, some of the 1-hexene product can be recycled for use as a reaction medium. Exemplary unsaturated aliphatic hydrocarbon compounds contemplated for use as catalytic reaction media include, but are not limited to, ethylene, 1-hexene, 1,3-butadiene and mixtures thereof. Exemplary unsaturated aromatic hydrocarbons useful as reaction media include, but are not limited to, benzene, toluene, ethylbenzene, xylene, mesitylene, hexamethylbenzene and mixtures thereof. Unsaturated aromatic hydrocarbons are preferred to improve the stability of the catalyst system and to produce a highly active and selective catalyst system. The most preferred unsaturated aromatic hydrocarbon is ethylbenzene because of its improved catalytic system activity and product selectivity. The trimerization process is generally carried out in a slurry or suspension of the catalytic components in a medium or diluent or inert. Broadly, the common trimerization reaction diluents can be liquid paraffins, cycloparaffins, olefins or aromatic hydrocarbons. Exemplary reactor diluents include, but are not limited to, isobutane, cyclohexane and methylcyclohexane. Isobutane can be used for improved compatibility with the polymerization processes of known olefins. However, a homogeneous trimerization catalyst system is more easily dispersed in cyclohexane. Accordingly, a preferred diluent for a homogeneous catalyzed trimerization process is cyclohexane. According to another embodiment of this invention, a slurry process can be carried out in a diluent (medium) which is a product of the olefin oligomerization process. For this, the choice of reactor or medium diluent is based on the selection of the initial olefin reagent. For example, if the oligomerization catalyst is used to trimerize ethylene to 1-hexene, the solvent for the oligomerization reaction would be 1-hexene. If ethylene and hexene will be trimerized to produce 1-decene, the oligomerization reaction solvent would be 1-decene. If 1, 3-butadiene were trimerized at 1, 5-cyclooctadiene, the solvent in the trimerization reactor would be 1.5-cyclooctadiene. The catalyst system comprising a chromium source, a pyrrole, alkyl metal-containing compound and reaction means may contain additional components which do not adversely affect and which improve the resulting catalyst system, such as, for example, halides.

Equipment The trimerization reaction can be conveniently carried out in a suitable reactor, preferably a continuous feed autoclave reactor with a fluid jacket or internal heat transfer coil and any suitable application mechanisms, such as for example mechanical agitation a gas inert, commonly nitrogen, purge, pipe and valves. Any other appropriate reaction equipment can also be used. For example, a circuit reactor with mechanical agitation, such as, for example, a stirring pump, can be used.

Reaction Conditions The trimerization reaction products, as defined in this specification, can be prepared from catalyst systems of this invention by dispersion reaction, slurry reaction or gas phase reaction techniques using contact equipment and processes. conventional The contact of the monomer or monomers with a catalyst system can be effected by any manner known in the art. A convenient process for suspending the catalytic system in the reaction medium and stirring the mixture to maintain the catalytic system in dispersion throughout the trimerization process. Other known contact processes can also be employed. Commonly, the catalyst system and reaction media are introduced to the reactor either continuously or in one or more fillers and the olefin reagent is introduced continuously or intermittently throughout the reaction as a gas under pressure. The pressure in the reactor is usually maintained by adding a gaseous olefin reagent at an appropriate rate to replace the olefin consumed by the reaction. Hydrogen can be charged to the reactor during the reaction to improve the reaction rate and improve the activity of the catalyst system and selectivity of the trimer product. The presence of hydrogen may be advantageous for reducing the by-product polymers in a powdery, non-sticky form, which is easily separated from the reactor and easily separated from the effluent, such as by filtration and / or evaporation. The hydrogen partial pressure present is usually from about 0.1 to about 100 Kg / cmz (about 1 to 1000 N / cirr), preferably from about 0.1 to about 80 Kg / cm (about 1 to 800 N / cmn). The reaction temperature employed can be any temperature that can trimerize the olefin reagents. In general, the reaction temperatures are within a range of about 0 ° C to about 150 ° C. Preferably, reaction temperatures in a range of about 60 ° C to about 200 ° C and more preferably within a range of about 80 ° C to about 150 ° C are employed. When the reagent is predominantly ethylene, a temperature in the range of about 0 ° C to about 300 ° C can generally be used. Preferably, when the reagent is predominantly ethylene, a temperature in ranges of about 60 ° C to about 11 ° C is employed. If the reaction temperature is too low, the polymer tends to adhere to the surface of the reactor. If the reaction temperature is too high, the catalyst system and the reaction products can decompose. The overall reaction pressure employed can be any pressure that can trimerize the olefin reagents. In general, pressures are in a range of about atmospheric pressure (0 N / cpr or 0 pounds / square inch of monometric pressure) to about 1700 N / cm2 gauge pressure (2500 pounds / square inch gauge). Preferably, the reaction pressures in a range of about atmospheric pressure to about 690 N / cm "gauge pressure (1000 pounds / square inches gauge) and more preferably in a range of about 200 to about 620 N / cm2 Gauge pressure (300 to 900 pounds / square inch gauge) are employed If the reaction pressure is too low, the activity of the catalytic system may be too low. The maximum pressure in general is determined by safety concerns and the desire for containers that have walls no thicker than necessary. The content of the reactor can be stirred or shaken by a purge of inert gas (eg, nitrogen) by introducing the reagent, hydrogen, fluid medium or catalyst or effluent exhaust in a manner that causes stirring, by mechanical or magnetic stirring or in any other appropriate way. The reaction is usually put into operation continuously by easily loading the lower 1-olefin reagent (s) and process media and separating the liquid reactor content. For example, a continuous stirred tank reactor system can be employed that includes feed systems for the catalytic, reactive and medium system and a discharge system for the effluent. You can also use a batch process, however. The effluent from the reactor is treated to deactivate the rest of the catalytic system, separate the products, recycle the residual reagents, medium and other appropriate components for recycling and dispose of any components that are not recycled. The trimerization reaction is exothermic, so that the reaction temperature can usually be regulated by circulating incremental water through a jacket or heat transfer coil, thereby transferring heat away from the reactor. It is important to have the ability to transfer heat efficiently out of the reactor, such that the reactor can be effectively maintained at the desired reaction temperature and the heat can be removed using a minimum amount of the cooling medium. Another advantage of the most effective heat transfer is that the trimerization reaction can be put into operation at a higher yield for a new temperature, which can improve the production efficiency. After the catalyst system has been used to prepare one with more olefin products, the reactor effluent stream comprising olefin trimer product (s), catalyst system and some higher polymer or oligomer byproducts is contacted with a catalyst deactivating agent to "deactivate", inactivate or extinguish the catalyst. Exemplary catalyst deactivating agents contemplated herein are alcohols, primary or secondary amines or alkanolamines. Any alcohol that can be easily dispersed in the stream of the reactor effluent can be used as a catalyst deactivating agent. For example, lower alcohols such as methanol, ethanol, propanol, isopropanol, etc., can deactivate the catalyst system. Preferably, however, an alcohol is selected that has a boiling point or molecular weight such that the alcohol will not form an azeotrope with the olefin monomer product. In general, materials with similar boiling points and similar molecular weights are more likely to form azeotropes. In an exemplary process, in which the catalyst system is used to trimerize ethylene to 1-hexene, a monofunctional alcohol with six or more carbon atoms per molecule is preferred as the catalyst deactivating agent. More preferably, a monofunctional alcohol having six to twelve carbon atoms per molecule is used for a better shutdown of the catalyst system. Such alcohols are easily separable from the 1-hexene olefin product. Exemplary monofunctional alcohols include, but are not limited to, 1-hexanol; 2-hexanol; 3-hexanol; 2-ethyl-1-hexanol; 3-octanol; 1-heptanol; 2-heptanol; 3-heptanol; 4-heptanol; 2-methyl-3-heptanol; 1-octanol; 2-octanol; 3-octanol; 4-octanol; 7-methyl-2-decanol; 1-decanol; 2-decanol; 3-decanol; 4-decanol; 5-decanol; 2-ethyl-1-decanol and mixtures thereof. Alternatively, a low molecular weight diol or polyol, for example, ethylene glycol, can be used as a catalyst deactivating agent. Diols and polyols commonly have higher boiling points than monoalcohols of comparable molecular weight and thus can be separated more easily from 1-hexane. The alcohol is used in an amount that is at least partially effective in quenching the catalyst. For example, alcohol may be added in a molar ratio of from about 0.01 to about 100, preferably from about 0.01 to about 10, more preferably from about 0.05 to about 2, relative to the metal content of the catalyst to be deactivated. If an alcohol is used as the catalyst deactivating agent for a halogenated catalyst system, halides that hydrogen can be generated, as previously described. Those who manufacture higher olefins will commonly choose to avoid or reduce the production of hydrogen halides. The problem of the hydrogen halide can be treated by treating the product stream with a stabilizing material that forms a stable halide or hydrogen halide salt. The stabilizing material contemplated herein may be an aliphatic amine, an aromatic amine, a metal salt of an amide, a metal salt of a butoxide, a metal salt of a carboxylic acid or a combination of these materials. More specifically, the stabilizing material in the present invention can be selected from cyclic and acyclic, aromatic and aliphatic amines, nitriles, amides, etc. The primary amines contemplated as stabilizing materials include ethylamine, isopropylamine; cyclohexylamine; benzylamine; naphthylamine and others. Secondary amines include diethylamine; diisopropylamine, dibutylamine; dicyclohexylamine; dibenzylamine and bis (trimerylsilyl) amine. The stabilizing material can be a tertiary amine such as tributylamine. The cyclic and aromatic amines and related compounds contemplated herein as stabilizing materials include aniline, pyridine, dimethylpyridine; morpholine; imidazole; indoline; indole; pyrrole; 2,5-dimethylpyrrole; 3, -dimethylpyrrole; 3, 4-dichloropyrrole; 2, 3, 4, 5-tetrachloropyrrole; 2-acetylpyrrole; pyrazole; pyrrolidine; pyrrolidone and dipyrrilmethane. The stabilizing materials contemplated herein may be alkanolamines. A particular advantage of alkanolamines is that the same molecule possesses both alcohol functionality and amine functionality, which can both contribute to deactivating both deactivating the catalyst system and stabilizing against the generation of corrosive hydrogen halides. Exemplary alkanolamines include isopropanolamine, monoethanolamine, diethanolamine and triethanolamine. The stabilizer materials contemplated herein also include polyamines. Exemplary poiyamines are ethylenediamine, diethylene triamine and tetramethylethylenediamine.

The metal salts of amides which can be used in the present invention as stabilizers include salts of, for example, dimethylformamide; N-methylformamide; acetamide, N-methylhexanamide; succinimide; maleamide; N-methylbenzamide; imidazole-2-carboxamide; di-2-tenolamin; beta-lactam; delta-lactam or epsilon-lactam with metals of group IA, IIA or IIB of the periodic table of the elements. Examples of such metal amides are lithium amides, sodium ethylamide, calcium tethylethylamide; lithium diisopropylamide; potassium benzylamide; sodium bis (trimethylsilyl) amide; lithium indole; sodium pyrrolide; lithium pyrrolide; potassium pyrrolide; potassium pyrrolidide; diethylaluminum pyrrolide, ethylaluminum dipyrrolide; aluminum tripyrrolide; 2, 5-dimethylpyrrolide sodium; Lithium 2,5-dimethylpyrrolide; 2, 5-dimethylpyrrolide potassium; 2, 5-d? Potassium methylpyrrolidide; diethyl aluminum; 2,5-dimethylpyrrolide; ethylaluminum; di (2,5-dimethylpyrrolide); tri (2, 5-dimethylpyrrolide) aluminum and combinations thereof. The imides usable in the present invention as stabilizers include 1,2-cyclohexanedicarboxymid, succinimide, phthalimide, maleimide, 2,, 6-piperidintone and perhydroazesine-2, 10-dione. The metal salts of butoxides usable herein are the butoxide salts of alkali metals (described further). An exemplary butoxide salt is potassium tert-butoxide. The metal salts of carboxylic acids useful herein as stabilizers include the metal salts, more in particular, the lithium, sodium, potassium and / or rubidic salts of carboxylic acids. Examples of the carboxylic acids include acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, heptanoic acid, octanoic acid, nonanoic acid, decanoic acid, benzoic acid, phenylacetic acid, phthalic acid, malonic acid, succinic acid, glutaric acid , adipic acid, acrylic acid, maieic acid, fumaric acid and salicylic acid. An exemplary carboxylic acid salt contemplated herein is silver acetate, lithium acetate, sodium acetate, potassium acetate and mixtures thereof. Exemplary phosphines useful herein as stabilizers include tributyl phosphine oxide and triethylphosphine. The stabilizing material must be provided in an effective amount to reduce at least the generation of hydrogen halide gas. For example, from about 0.01 to about 100 moles, preferably from about 0.01 to about 10 moles, more preferably from 0.05 to 2 moles of stabilizing material can be added per mole of halogen in the catalysts. The use of an alcohol is not essential to turn off or deactivate the catalyst. Other materials, for example primary or secondary amines, can be used to deactivate a catalyst, either alone or in combination with one or more alcohols. In general, a first aliphatic amine, a secondary aliphatic amine or a combination of those materials are contemplated for use as a catalyst deactivating agent. More specifically, the amines can be acyclic aliphatic amines or cyclic aliphatic amines, within the scope of the invention. As with alcohol, the amine quench material can be provided in an effective amount to at least substantially quench the catalyst, either alone or when combined with an alcohol or other quenching agent.

* Sufficient of the deactivating agent the catalyst is added to the reactor effluent stream to at least substantially quench, deactivate or "inactivate" the olefin production catalyst system and reduce or eliminate the production of undesirable solids, particularly polymer or catalyst solids. If an insufficient amount of catalyst deactivating agent is used, any metals in the catalyst system, such as chromium or aluminum can precipitate and interfere with the future effluent process. In general, up to about five equivalents of catalyst deactivating agent can be added per mole of metals in the effluent stream. Preferably, the amount of the catalyst deactivating agent is added from about one to about four molar equivalents and more preferably the amount of deactivating agent of the added catalyst is from about two to about three molar equivalents of catalyst deactivating agent. mol of metals in the reactor effluent stream. Too much catalyst deactivation agent can cause reactor corrosion. After the catalyst system has been turned off and treated to stabilize any halides, the olefin products, such as for example 1-hexene can be separated. Any separation process can be used, although distillation is preferred for ease of use. In a simple distillation, the ethylene is separated from the reaction product, then the 1-hexene and the medium are distilled from the reaction dispersion while the catalyst components are concentrated and recovered together with the polyethylene byproduct. The critical distillation temperatures in the distillation kettles are maintained at about 190 ° C to about 210 ° C. It is believed that these distillation temperatures are sufficient to promote the decomposition of the aluminum halides present in the spent catalyst to produce hydrogen halides, unless steps are undertaken as described herein to prevent generation of hydrogen halide. The concentrated dispersion containing by-product polymer and catalyst components can be discarded and can be further treated as described hereinafter. The product stream produced by the ethylene trimerization process commonly contains one or more of the following compounds, butene; 1-hexene; internal hexenes (that is, 2-hexene or 3-hexene); octene; tens; reaction medium and "heavy". The waste product stream formed by separating the desired olefin monomer products can be further processed by contacting an aqueous base to remove the metals. Organic bases are not preferred at this point because the organic bases may be too weak to precipitate heavy metals, such as chromium. The preferred aqueous inorganic bases are sodium hydroxide and potassium hydroxide because of their ease of use, availability, low cost and beneficial effects on future processing. The amount of added aqueous inorganic base can be any amount sufficient to precipitate most or substantially all of the chromium. The most important goal of this stage is to prepare the chromium there were other heavy metals, since any remaining dispersed aluminum does not raise the same environmental issues. The addition of too much or too little of the aqueous inorganic base can prevent the precipitation of chromium. In general, up to about 4 molar equivalents of aqueous inorganic base should be used per mole of chromium and aluminum. Preferably, from about 0.2 to about 3 molar equivalents and more preferably from about 1 to 2 molar equivalents of the aqueous inorganic base can be used per mole of chromium and aluminum. Then, the solid precipitate containing chromium can be separated and disposed of properly. After removal of the solid precipitate containing chromium, the inorganic aqueous layers or portions are separated. The organic layer can be discarded.

Waste Removal The trization process commonly produces two residues that can accumulate on the internal surfaces of the reactor. A residue, for a long trecognized to accumulate on the walls of the reactor, is an oligomer or a polymer having a chain length higher than the desired product, formed as a by-product. This residue of allgomer or higher polymer is referred to herein, for the sake of simplicity, only as "polymer residue". For example, in the case of an ethylene reaction, the polyethylene residue or paraffin wax can be formed and accumulated on the internal surfaces of the reactor. This polymer waste reduces the efficiency of the thermal transfer of the internal surface of the reactor. The polymeric residue can be separated from the apparent reactor by washing the reactor with a solvent for the residue. The trization reactor is commonly fed with a solvent by sub-product polymers - such as cyclohexane or methylcyclohexane - as the process medium. When a polymeric solvent is used as the process medium, the same process medium can be used to periodically wash the reactor. The washing conditions can be more severe than the usual process conditions, to separate the waste from the polymer that is not separated under the usual process conditions. For example, the washing step may be a "hot wash" performed by circulating the process medium from usual to the temperature higher than the process temperature to melt, dissolve more quickly or otherwise dislodge the polymer waste. In a continuous ethylene trization process, the hot wash may be as follows. The reaction can be stopped by interrupting the feeding of catalyst and reagents while continuing to inject and drain the reaction medium, which can be, but is not limited to, cyclohexane and / or methylcyanohexane and increase the temperature of the medium to approximately 60 ° C to 70 ° C. The hot wash is continued for several hours, or as necessary to remove all of substantially all the polymer residue. It has been found that this hot washing separates the accumulation of polymer residue. A second residue, which also substantially impairs the thermal transfer efficiency of the reactor, is referred to herein as a catalytic waste. The exact chemical constitution of this catalytic residue is not known. A precipitate may be a deposit of the entire catalyst or one or more of the catalytic ingredients, the product of a reaction between the catalyst ingredients, the catalyst and the reactor wall, depleted constituents of the catalyst, a combination of these residues or some another thing. It is believed that the residue is associated with the catalyst, although the present invention is not limited by the accuracy of that theory. A further understanding of how to make and use the present invention and its advantages will be provided by reference to the following examples.

EXAMPLES Example 1 To a one liter three neck flask purged with inert gas equipped with nitrogen purge, magnetic stirrer, glass column, Dean-Stark tube and condenser is added 250 ml of anhydrous dodecane and 260 ml of 2-ethyl -2-hexanol. The system was purged again for 20 minutes and 50 ml of the selective 1-hexene catalyst (5 mg Cr / l) was added. Water (2 ml) is added and the system was heated to reflux. Nine samples were taken for 5 hours. The acidity was determined by extraction in water of the samples taken from the Dean Stark tube and water test with pH paper. A first sample was moderately acidic and all other samples were very acidic. It was observed that water was present in the last sample. Example 2 Example 1 was repeated but in addition to the 2 ml of water, 4 ml of tri-n-butylamine are also added. None of the nine subsequent samples of the Dean-Stark tube were acidic demonstrating the effectiveness of adding an amine to the process. Water was observed in the ninth sample, as it was observed in Example 1. The presence of the amine separates all the signs of acidity.

Experimental Apparatus for Examples 3 and 4 The apparatus used for Examples 3 and 4 was a one-liter three neck necked round flask equipped with a glass cavity for a thermocouple to check the temperature of the kettle, an additional funnel and a Dean-Stark tube. A condenser was placed on top of the Dean-Stark tube, also as a thermocouple to measure the upper temperature and a wire that retained a piece of pH paper at the top of the Dean-Stark tube. The flask was also equipped with a stirring-magnetic bar and a stirrer and a heating blanket. A stream of nitrogen constantly swept material through the apparatus and a bubbler containing water.

General Procedure for Examples 3 and 4 In a typical experiment, 200 g of dodecane are added to the flask and the system is purged with nitrogen. Diethylaluminum chloride (DEAC) (1.9 M) in dodecane was then charged to the flask from a metal cylinder. Then the desired amount of 2-ethyl-1-hexanol was slowly added and allowed to react. The temperature would rise to approximately 50-70 ° C and the gas evolution is observed. The contents for 30 minutes to allow the complete reaction and samples are taken from the kettle. Then the contents were heated to reflux. The exit vapors were separated as necessary to obtain the desired temperature of the boiler. Samples of the exit vapors (approximately 2 ml) were periodically taken from the Dean-Stark tube.

Example 3 The following materials were added to the apparatus described above: 200 g of anhydrous dodecane, 80.8 ml of a 1.9 M solution of DEAC in dodecane and 96 ml of 2-ethyl-1-hexanol were slowly added. This mixture was heated to a boiler temperature of 170 ° C to 209 ° C for 2.75 hours. They made the. following observations. Immediately after the addition of the alcohol there was no change in color of the pH paper at or high of the Dean-Stark tube and the pH of the water sparger was neutral. After heating, the pH paper in the Dean-Stark tube became reddish-purple (strongly acidic). The samples from the bottom of the Dean-Stark tube moistened the pH paper to indicate acidity and the chloride test with silver acetate was positive. It was clear that acid hydrochloric acid was present.

Example 4 The following materials were added to the apparatus described above: 200 g of anhydrous dodecane, 81 ml of a 1.9 M solution of DEAC in dodecane and 96 ml of 2-ethyl-1-hexanol were slowly added. Tri-n-butylamine (40.25 g) is added. This mixture was heated to a boiler temperature of 208 ° C for four hours. The following observations were made. There was no change in pH paper color at the top of the Dean-Stark tube throughout the experiment. The pH of the water sparger was neutral at the end of the experiment. The samples from the bottom of the Dean-Stark tube were neutral or slightly basic as indicated by the moist pH paper. It was clear that any separated acid was removed from the system by the addition of the amine. While this invention has been described in detail for the purpose of illustration, it is not to be construed as limited by it, but rather to cover all changes and modifications within the spirit and scope thereof. It is noted that, in relation to this date, the best method known to the applicant to carry out the invention citation is that which is clear from the present description of the invention.

Claims (35)

1. CLAIMS Having described the invention as above, the content of the following claims is claimed as property: 1. An oligomerization process characterized in that it comprises: (a) providing at least one catalyst system, at least one lower olefin and at least one a means of process; (b) reacting said lower olefin in the presence of the catalyst system to produce a product stream comprising a higher olefin product and a catalyst system residue dispersed in such a process medium; (c) treating such product stream with a quenching material comprising a primary aliphatic amine, a secondary aliphatic amine, an aliphatic tertiary amine or a combination of those materials, such quenching material is provided in an effective amount to quench at less substantially such a catalyst system.
2. 2. The process according to claim 1, characterized in that said quenching material comprises an acyclic aliphatic amine.
3. 3. The process according to claim 1, characterized in that said quenching material comprises a cyclic aliphatic amine.
4. 4. The process according to claim 1, characterized in that said quenching material comprises a primary amine.
5. 5. The process according to claim 1, characterized in that said quenching material comprises a secondary amine.
6. 6. The process in accordance with the claim 1, characterized in that said quenching material comprises cyclohexylamine.
7. The process according to claim 1, characterized in that said quenching material comprises dibutylamine.
8. 8. The process according to claim 1, characterized in that said quenching material comprises an alkanolamine.
9. 9. The process according to claim 1, characterized in that said quenching material comprises isopropylamine.
10. 10. The process according to claim 1 characterized in that said quenching material comprises monoethanolamine.
11. 11. The process according to claim 1, characterized in that said quenching material comprises diethanolamine.
12. 12. The process according to claim 1, characterized in that said quenching material is separable from the higher olefin by distillation.
13. 13. The process according to claim 1, characterized in that said quenching material further comprises an alcohol.
14. 14. The process according to claim 1, characterized in that said quenching material is added in a molar ratio of about 1 to about 5, relative to the metal content of such a catalyst.
15. 15. An oligomerization process, characterized in that it comprises: (a) providing a halogenated catalyst system, a lower olefin and a process medium; (b) reacting such lower olefin in the presence of the catalyst system to produce a product stream comprising a higher olefin product and a catalyst system residue dispersed in such a process medium; (c) treating such product stream with an alcohol in an amount effective to quench at least partially the catalyst system and (d) treating such product stream with a stabilizing material that forms a stable hydrogen halide salt, such a stabilizing material is provided in an effective amount to reduce the generation of hydrogen halide gas.
16. 16. The process according to claim 15, characterized in that said stabilizing material is selected from an aliphatic amine, an aromatic amine, a metal salt of an amine, a metal salt of a butoxide, a metal salt of an acid carboxylic or a combination of those materials.
17. 17. The process according to claim 15, characterized in that said stabilizing material comprises an acyclic aliphatic amine.
18. 18. The process according to claim 15, characterized in that said stabilizing material comprises a cyclic aliphatic amine.
19. 19. The process according to claim 15, characterized in that said stabilizing material comprises an aromatic amine.
20. 20. The process according to claim 15, characterized in that said stabilizing material comprises a primary amine.
21. 21. The process according to claim 15, characterized in that said stabilizer material comprises a secondary amine.
22. 22. The process according to claim 15, characterized in that said stabilizing material comprises a tertiary amine.
23. 23. The process according to claim 15, characterized in that said stabilizing material comprises an alkanolamine.
24. 24. The process according to claim 15, characterized in that said stabilizing material comprises isopropylamine.
25. 25. The process according to claim 15, characterized in that said stabilizing material comprises monoethanolamine.
26. 26. The process according to claim 15, characterized in that said stabilizing material comprises diethanolamine.
27. 27. The process according to claim 15, characterized in that said stabilizing material comprises cyclohexylamine.
28. 28. The process according to claim 15, characterized in that said stabilizing material comprises dibutylamine.
29. 29. The process according to claim 15, characterized in that said stabilizing material comprises tributylamine.
30. 30. The process according to claim 15, characterized in that said stabilizing material comprises ethylene diamine.
31. 31. The process according to claim 15, characterized in that said alcohol has at least six carbon atoms per molecule.
32. 32. The process according to claim 15, characterized in that such alcohol and such stabilizing material are separated from the higher olefin by distillation.
33. 33. The process according to claim 15, characterized in that said alcohol is 2-ethylhexanol.
34. 34. The process according to claim 15, characterized in that said alcohol is added in a molar ratio of about 0.01 to about 100, relative to the metal content of such a catalyst.
35. 35. The process according to claim 15, characterized in that such stabilizer material is added in a molar ratio of about 0.01 to about 100, relative to the metal content of such a catalyst.