Method for treating ethylene oligomerization waste catalyst mixture

Abstract

The invention provides a method for treating an ethylene oligomerization waste catalyst mixture, and relates to the technical field of catalyst inactivation treatment. The method for treating the ethylene oligomerization waste catalyst mixture mainly comprises the following steps: mixing the waste catalyst mixture containing a metal catalyst, an aluminum-based activating agent and an ethylene oligomerization product with a solvent, and carrying out inactivation treatment by adopting an ether alcohol inactivating agent. According to the method, the tradition that high-price, harmful and non-biodegradable long-chain amine and long-chain alcohol inactivators and low-boiling-point inactivators which can influence the product quality are used for treating the waste catalyst is abandoned, and a biodegradable ether alcohol inactivator which is low in price and high in boiling point is adopted; by adopting the inactivator, the pollution of ethylene polymerization products, recovered solvents and recovered ethylene cannot be caused.

Description

Technical Field

[0001] The invention relates to the technical field of catalyst deactivation treatment, and in particular to a method for treating an ethylene oligomerization waste catalyst mixture. Background Art

[0002] At present, homogeneous catalysts of transition metals combined with aluminum-based co-catalysts are commonly used in the industry for the preparation of 1-butene by ethylene dimerization, 1-hexene by trimerization, 1-octene by tetramerization, and alpha-olefins by oligomerization. Amines and alcohol compounds are often used as deactivators of ethylene oligomerization catalysts. In the case of using homogeneous catalytic technology, in addition to the reaction itself, there are also problems of separating and separating the desired product from the crude reaction mixture including the spent catalyst mixture, such as how to deactivate the catalyst and separate it, and the biggest challenge is to make the presence of catalyst residues not impair the purity of the initial product by uncontrolled reaction. In particular, it must be noted that the purification process downstream of the reactor will not reduce the purity of the desired product, thereby reducing its value.

[0003] Patent CN111434668 describes an ethylene polymerization method, an ethylene trimerization method and an ethylene tetramerization method based on a chromium-based and aluminum-based catalyst system, and discloses a fluorine-containing polymer as a ligand for an ethylene polymerization catalyst, which can effectively improve the catalytic performance of the catalyst system, improve the activity and selectivity, and use ethanol as a reaction terminator.

[0004] Patent CN1137509 provides an improved method for producing 1-butene by ethylene dimerization reaction, which includes a very effective catalyst removal part. The reactor effluent is contacted with a sufficient amount of oxygen-polar or nitrogen-polar compound catalyst inhibitor to fully deactivate all catalysts present in the effluent, and the first, second and third gas phases are obtained through a flash tower and an evaporation tower to form a gas phase reactor effluent that is substantially free of spent catalyst.

[0005] Patent FR2581381 describes a method for terminating a titanium-based catalyst system in which the crude effluent from the dimerization step is contacted with an amine containing 5 to 22 carbon atoms. In particular, the amine can be used within a specific range of molar ratios between the amine and the titanium compound. Despite the robustness of the method in which the neutralization step is carried out with an amine, the use of amines has limitations, particularly at the industrial level, due to their toxicity.

[0006] Patent EP0221206 discloses a method for dimerizing ethylene to but-1-ene with improved yield and selectivity without the formation of by-products by using a catalyst system based on titanium and alkylaluminum in the presence of optional additives in a specific mass ratio. It is pointed out that the dimerization reaction can be terminated by adding an alcohol containing 1 to 4 carbon atoms to the reaction mixture.

[0007] IFP patent CN109942362 terminates the catalytic system by adding alcohols such as 2-ethylhexanol and 1-dodecanol to the reaction mixture. One advantage of the process of the present invention is that the yield of butene-1-ene in the ethylene dimerization reaction is improved by significantly reducing side reactions such as the isomerization of butene-1-ene to butene-2-ene or uncontrolled addition reactions that can occur during contact between the reaction effluent and the catalyst in the reboiler of the flash column or distillation column necessary for separating butene-1-ene.

[0008] Those skilled in the art are constantly searching for new methods to improve ethylene oligomerization while maintaining alpha-olefin selectivity in post-reaction workup steps. Summary of the invention

[0009] In view of the shortcomings of the prior art, the present invention provides a method for treating a mixture of spent catalysts from ethylene polymerization, using a biodegradable ether alcohol deactivator that is inexpensive and has a high boiling point. This type of deactivator has a high boiling point and will not enter the product during distillation to affect the purity of the product. In addition, it is inexpensive and can achieve the purpose of deactivating the catalyst while saving production costs and improving production efficiency.

[0010] To achieve the above objectives, the technical solution of the present invention is implemented through the following technical solutions:

[0011] A method for treating a spent ethylene oligomerization catalyst mixture, the method comprising the following steps:

[0012] S1. A spent catalyst mixture containing 0.001%-10% of a metal catalyst, 0.002%-20% of an aluminum-based activator, and 0.1%-99.9% of an ethylene oligomerization product is mixed with a solvent according to mass percentage and added into a reactor, wherein the metal catalyst is selected from any one of a titanium compound, a chromium compound, a nickel compound, and a zirconium compound;

[0013] S2, select any one of R5O(CR6R7)nOH and R5O(CR6R7CR8R9)nOH as the inactivator, where R 5～9 Any one of H and C1-C20 hydrocarbon groups;

[0014] S3. Add a deactivator into the reactor at a ratio of Al / OH=1:0.5-10, stir and react, and complete the deactivation treatment of the spent catalyst mixture.

[0015] Preferably, the titanium compound in step S1 is Ti(OR1)(OR2)(OR3)(OR4), R 1～4 is a C1-C20 hydrocarbon group, aliphatic or aromatic, cyclic or linear, and may contain heteroatoms such as O, N, S, etc.; and R 1～4It is any one or a mixture of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, n-hexyl, 2-ethylhexyl, phenyl, 2-methylphenyl, 4-methylphenyl, 2,6-dimethylphenyl, acid / ester / carboxyl / acyl / amide.

[0016] Preferably, in step S1, the chromium compound is selected from organic or inorganic salts, coordination complexes and metal organic complexes of chromium, and the chromium compound is any one of chromium acetylacetonate, chromium chloride tetrahydrofuran complex, chromium octoate, chromium hexacarbonyl, and chromium 2-ethylhexanoate, or a mixture of several thereof.

[0017] Preferably, the zirconium compound in step S1 is selected from organic or inorganic salts, coordination complexes and metal organic complexes of zirconium; and the zirconium compound is any one or a mixture of chromium acetylacetonate-chromium chloride-tetrahydrofuran complex (1:3), chromium octoate, chromium hexacarbonyl, and chromium 2-ethylhexanoate.

[0018] Preferably, the solvent in step S1 is any one or a mixture of several C5-C20 hydrocarbon solvents.

[0019] Preferably, the aluminum-based activator in step S1 is any one of trimethylaluminum, triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, diisobutylaluminum hydride, diethylaluminum chloride, ethylaluminum dichloride, sesquiethylaluminum chloride, sesquimethylaluminum chloride, and aluminoxane compounds, or a mixture of several of them.

[0020] Preferably, the aluminoxane compound is any compound containing an -Al(R)-O- structural unit, which is any one of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, and modified methylaluminoxane, or a mixture of several thereof; and the modified methylaluminoxane is obtained by modifying methylaluminoxane with different modifiers, including but not limited to butyl, isobutyl, tert-butyl, alkoxy, and alkylamino modifications.

[0021] Preferably, the inactivator is any one of tripropylene glycol methyl ether, tripropylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, tetraethylene glycol monododecyl ether, trimerethylene glycol monododecyl ether, ethylene glycol monododecyl ether, ethylene glycol butyl ether, dipropylene glycol, and a mixture of any one of fatty alcohol polyoxyethylene ether or several thereof.

[0022] Preferably, in step S3, the reaction temperature is 20-150° C., the reaction pressure is 1-10 atm, the reaction time is 0.1-10 h, and the stirring speed is 10-1000 rpm.

[0023] The present invention provides a method for treating a mixture of spent ethylene oligomerization catalysts, which has the following advantages over the prior art:

[0024] The present invention abandons the traditional method of using expensive, harmful and non-biodegradable long-chain amine and long-chain alcohol deactivators and low-boiling point deactivators that affect product quality to treat waste catalysts, and adopts low-cost high-boiling point biodegradable ether deactivators to treat ethylene polymerization waste catalysts; it avoids product changes that may occur during product separation, such as isomerization, and eliminates the potential pollution of the deactivator to the recovered ethylene, recovered solvent and products. The use of such deactivators is cheaper than traditional deactivators, can reduce industrial production costs, and improve production efficiency. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention is clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Example:

[0027] Method for treating spent ethylene oligomerization catalyst mixture:

[0028] (1) placing a spent catalyst mixture (including a metal catalyst, an aluminum-based activator, an ethylene polymerization product and a solvent) into a reactor;

[0029] (2) Add the inactivator to the reactor and start stirring at 10 rpm;

[0030] (3) Adjusting the reaction temperature and reaction pressure, controlling the reaction time to obtain a mixed product, and completing the deactivation of the catalyst.

[0031] Referring to the above method, select different catalyst mixtures and inactivators according to the table below, and record the inactivation rate of each group;

[0032]

[0033]

[0034] From the above tests, it can be seen that the deactivation rates of the spent catalysts in the experimental groups 1-10 are all above 98.5%, that is, the catalysts are effectively deactivated.

[0035] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for treating a spent catalyst mixture of ethylene oligomerization, characterized in that: The method comprises the following steps: S1. A spent catalyst mixture containing 0.001%-10% of a metal catalyst, 0.002%-20% of an aluminum-based activator, and 0.1%-99.9% of an ethylene oligomerization product is mixed with a solvent according to mass percentage and added into a reactor, wherein the metal catalyst is selected from any one of a titanium compound, a chromium compound, a nickel compound, and a zirconium compound; S2, select any one of R5O(CR6R7)nOH and R5O(CR6R7CR8R9)nOH as the inactivator, where R 5～9 Any one of H and C1-C20 hydrocarbon groups; S3. Add a deactivator into the reactor at a ratio of Al / OH=1:0.5-10, stir and react, and complete the deactivation treatment of the spent catalyst mixture.

2. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: The titanium compound in step S1 is Ti(OR1)(OR2)(OR3)(OR4), R 1～4 It is any one or a mixture of methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, pentyl, isopentyl, n-hexyl, 2-ethylhexyl, phenyl, 2-methylphenyl, 4-methylphenyl, 2,6-dimethylphenyl, acid / ester / carboxyl / acyl / amide.

3. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: In step S1, the chromium compound is selected from any one of chromium acetylacetonate, chromium chloride tetrahydrofuran complex, chromium octoate, chromium hexacarbonyl, and chromium 2-ethylhexanoate, or a mixture of the two or more thereof.

4. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: In the step S1, the zirconium compound is selected from any one of chromium acetylacetonate, chromium chloride tetrahydrofuran complex, chromium octoate, chromium hexacarbonyl, and chromium 2-ethylhexanoate, or a mixture of several of them.

5. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: The solvent in step S1 is any one or a mixture of several C5-C20 hydrocarbon solvents.

6. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: The aluminum-based activator in step S1 is any one of trimethylaluminum, triethylaluminum, tripropylaluminum, tri-n-butylaluminum, triisopropylaluminum, triisobutylaluminum, diisobutylaluminum hydride, diethylaluminum chloride, ethylaluminum dichloride, sesquiethylaluminum chloride, sesquimethylaluminum chloride, and aluminoxane compounds, or a mixture of several of them.

7. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 6, characterized in that: The aluminoxane compound is any one of methylaluminoxane, ethylaluminoxane, isobutylaluminoxane, and modified methylaluminoxane, or a mixture of several thereof; and the modified methylaluminoxane is obtained by modifying methylaluminoxane with different modifiers, including but not limited to butyl, isobutyl, tert-butyl, alkoxy, and alkylamino modifications.

8. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: The inactivator is any one of tripropylene glycol methyl ether, tripropylene glycol monobutyl ether, triethylene glycol monomethyl ether, triethylene glycol monobutyl ether, dipropylene glycol monomethyl ether, dipropylene glycol monobutyl ether, diethylene glycol monobutyl ether, ethylene glycol monomethyl ether, tetraethylene glycol monododecyl ether, trimethylene glycol monododecyl ether, ethylene glycol monododecyl ether, ethylene glycol butyl ether, dipropylene glycol, and a fatty alcohol polyoxyethylene ether, or a mixture of several of them.

9. The method for treating a spent ethylene oligomerization catalyst mixture according to claim 1, characterized in that: In step S3, the reaction temperature is 20-150° C., the reaction pressure is 1-10 atm, the reaction time is 0.1-10 h, and the stirring speed is 10-1000 rpm.

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