Method for producing α-olefins

Abstract

The present invention provides a method for producing α-olefins that can efficiently deactivate catalysts in polymerization reaction products and suppress the formation of organic halogen compounds as by-products. [Solution] The method includes step 1, in which ethylene and a catalyst are continuously introduced into a reactor and polymerized to obtain a reaction mixture, and step 2, in which the reaction mixture and a base are continuously introduced into a line mixer and mixed, wherein the stirring power of the line mixer is 30 to 1000 kW·sec / m 3 A method for producing α-olefins, wherein the number of passes is 5 to 50.

Description

[Technical Field]

[0001] This invention relates to a method for producing α-olefins. [Background technology]

[0002] Alpha-olefins are useful substances widely used as monomer raw materials for olefin polymers, as comonomers for various polymeric polymers, and as raw materials for plasticizers and surfactants. Various methods have been studied for producing α-olefins, but generally, for example, ethylene (2 carbon atoms) is polymerized at a low level using a Ziegler catalyst to obtain a mixture of α-olefins with 4 to 20 carbon atoms, or 20 or more carbon atoms, such as butene (4 carbon atoms), hexene (6 carbon atoms), and octene (8 carbon atoms). Then, the mixture is distilled using multiple distillation columns, and each α-olefin is isolated in order from the component with the fewest carbon atoms, to obtain the individual α-olefin or a mixture of α-olefins required for each application.

[0003] This manufacturing process generally consists of a polymerization reaction step, an unreacted ethylene recovery step, a catalyst deactivation step, a deashification step, and a solvent and α-olefin distillation step. Ziegler-type catalysts commonly used in the aforementioned manufacturing process contain halogen atoms (halide ions), so when the catalyst is deactivated, it reacts with water to generate hydrogen halides, which then react with hydrocarbon compounds in the reaction mixture to produce organic halogen compounds as byproducts. Attempts have been made to reduce such byproducts. For example, Patent Document 1 describes polymerizing ethylene in the presence of a Ziegler-type catalyst, aiming to achieve stable operation without problems such as clogging and to suppress the by-product formation of organic halogen compounds. After the polymerization reaction is complete, the reaction product is maintained at a temperature of 90°C or higher, at a rate of 3 kg / cm³. 2 A method is disclosed in which a basic nitrogen compound is introduced as a solution at a concentration of 10% by weight or more, relative to the halogen content of the Ziegler catalyst, at a pressure of 10% by weight or more, to deactivate the catalyst, as a pressure of 10% by weight or more. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 3-220135 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In the production of α-olefins, a stirred tank is considered a viable option for deactivating the catalyst while suppressing the formation of by-products such as organic halogen compounds. To suppress side reactions, the catalyst must be rapidly deactivated and diluted in water, requiring the introduction of a reaction mixture containing the catalyst and the α-olefin product into a large volume of water and a large volume of basic substance. However, this requires large and expensive equipment compared to the α-olefin production volume, making it unsuitable for continuous production. On the other hand, if catalyst deactivation is performed without using large volumes of water and basic substance for continuous production, it becomes difficult to suppress the formation of by-products such as organic halogen compounds. Therefore, there has been a need for equipment and methods that are compact, capable of high-speed deactivation, and can suppress the formation of organic halogen compounds, making them suitable for continuous production. Therefore, the object of the present invention is to provide a method for producing α-olefins that can efficiently deactivate catalysts in polymerization reaction products and suppress the formation of organic halogen compounds as by-products. [Means for solving the problem]

[0006] In view of the above circumstances, the inventors have conducted extensive research and have found that the above problem can be solved by a manufacturing method that includes a step of deactivating the catalyst when continuously introducing and mixing the polymerization reaction mixture and a base in a line mixer, while keeping the operating conditions of the line mixer within a specific range. In other words, the present invention relates to the following [1] to [5]. [1] Step 1 of continuously introducing ethylene and a catalyst into a reactor and performing a polymerization reaction to obtain a reaction mixture, and step 2 of continuously introducing the reaction mixture and a base into a line mixer and mixing them, wherein the stirring power in the mixing is 30 to 1000 kW·seconds / m 3 and the number of passes is 5 to 50, a method for producing an α-olefin. [2] Before continuously introducing the reaction mixture and the base into the line mixer, it includes a step of contacting the reaction mixture and the base, and the distance from the confluence point where the reaction mixture and the base contact to the line mixer inlet is 1 m or less. The method for producing an α-olefin according to [1] above. [3] The method for producing an α-olefin according to [1] or [2] above, wherein the catalyst is a Ziegler catalyst. [4] The method for producing an α-olefin according to any one of [1] to [3] above, wherein the base is ammonia. [5] After step 2, it further includes a deashing step 3 of removing the deactivated catalyst and a distillation step 4 of recovering the α-olefin. The method for producing an α-olefin according to any one of [1] to [4] above. [Advantages of the Invention]

[0007] According to the method for producing an α-olefin of the present invention, the catalyst in the polymerization reaction product can be efficiently deactivated, the by-production of organic halogen compounds can be suppressed, and α-olefin free of by-products can be efficiently obtained with inexpensive and compact equipment. [Brief Description of the Drawings]

[0008] [Figure 1] It is a schematic process diagram showing an example of the process for implementing the present invention. [Embodiments for Implementing the Invention]

[0009] The present invention comprises the steps of: 1) continuously introducing ethylene and a catalyst into a reactor and performing a polymerization reaction to obtain a reaction mixture; and 2) continuously introducing the reaction mixture and a base into a line mixer and mixing them, wherein the stirring power of the line mixer is 30 to 1000 kW·sec / m 3 This is a method for producing α-olefins, wherein the number of passes is 5 to 50. The steps of the present invention will be described below.

[0010] [Process 1] Step 1 is a step in which ethylene and a catalyst are continuously introduced into a reactor and polymerized to obtain a reaction mixture. In this step, ethylene is polymerized to obtain a reaction mixture containing α-olefins. <Catalyst> In step 1, a catalyst is used to polymerize ethylene. A Ziegler catalyst is preferred as the catalyst. The effects of the present invention are exhibited when a catalyst containing halogen atoms, such as chlorine, bromine, or iodine atoms, is used. The Ziegler catalyst preferably consists of a combination of (A) a transition metal compound, (B) an organoaluminum, and (C) a third component, which may be used as desired. Of these, compounds containing halogen atoms, especially chlorides, have a simple structure, are readily available, and are inexpensive, making them suitable for industrial production. They also exhibit excellent catalytic performance. According to the manufacturing method of the present invention, even when using such catalysts, α-olefins that do not contain organic halogen compounds can be efficiently obtained with inexpensive and compact equipment. (A) Examples of transition metal compounds include those represented by general formula (I). MX x Y y O z (I) [In the formula, M represents a zirconium atom or a titanium atom, X represents a chlorine atom, a bromine atom or an iodine atom, and Y represents RO-, R2N-, -OCOR, -OSO3R, R-, -Cp, or a β-diketnate represented by formula (II). -Cp represents a cyclopentadienyl group, and R represents a linear or branched alkyl group having 1 to 20 carbon atoms.] [Chemical Formula] (In formula (II), R 1 , R 2 and R 3 each independently represent a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an alkyl group having 1 to 20 carbon atoms substituted with a halogen atom. At least one of R 1 , R 2 and R 3 is an alkyl group having 1 to 20 carbon atoms substituted with a halogen atom.). x, y, and z each independently represent an integer from 0 to 4, and x + y + z = 4.〕 Preferably, M is a zirconium atom. Preferably, X is a chlorine atom. Preferably, x is 4. Preferably, y is 0. Preferably, z is 0.

[0011] ZrCl4,ZrBr4,ZrI4,ZrBrCl3,ZrBr2Cl2,TiCl4,TiBr 4,TiI4,TiBrCl3,TiBr2Cl2,Zr(OC2H5)4,Zr(OC2H5)2Cl2,Zr(On-C3H7)4 ,Zr(On-C3H7)2Cl2,Zr(O-iso-C3H7)4,Zr(O-iso-C3H7)2Cl2,Zr(On-C4H 9)4,Zr(On-C4H9)2Cl2,Zr(O-iso-C4H9)4,Zr(O-iso-C4H9)2Cl2,Zr(O-t ert-C4H9)4,Zr(O-tert-C4H9)2Cl2,Zr((CH3)2N)4,Zr((C2H5)2N)4,Zr((n-C3H7)2N)4,Zr((iso-C3H7)2N)4,Zr((n-C4H9)t-C4H9) 2N)4,Zr(OSO3CH3)4,Zr(OSO3C2H5)4,Zr(OSO3C3H7)4,Zr(OSO3C4H9)4,ZrCp2Cl2,ZrCp2ClBr,Ti(OC2H5)4,Ti(OC2H5)2Cl2,Ti(OC2H5)4,Ti(OC2H5)2Cl2,Ti(OC2H5)4,Ti(OSO3C2-4) C3H7)2Cl2,Ti(O-iso-C3H7)4,Ti(O-iso-C3H7)2Cl2,Ti(On-C4H9)4,Ti(On-C4H9)2Cl2,Ti(O-iso-C4H9)4,Ti(O-iso-C4H9)2Clter-OH 9)4,Ti(O-tert-C4H9)2Cl2,Ti((CH3)2N)4,Ti((C2H5)2N)4,Ti((n-C3H7)2N)4,Ti((iso-C3H7)2N)4,Ti((n-C4H9)2N)4,Ti((Tit-C4H9)2N)4,Ti((Tit-C4H9)2N)4 OSO3CH3)4,Ti(OSO3C2H5)4,Ti(OSO3C3H7)4,Ti(OSO3C4H9)4,TiCp2Cl2,TiCp2ClBr,Zr(OCOC2H5)4,Zr(OCOC2H5)2Cl2,Zr(OCOC3H7)4,ZOCH 7)2Cl2,Zr(OCOC4H9)4,Zr(OCOC4H9)2Cl2,Ti(OCOC2H5)4,Ti(OCOC2H5)2Cl2,Ti(OCOC3H7)4,Ti(OCOC3H7)2Cl2,Ti(OCOC4H9)4,Ti(OCOC4H9)2,2Cl2Examples include ZrCl2(HCOCFCOF)2 and ZrCl2(CH3COCFCOCH3)2. Among these, ZrCl4, Zr(On-C3H7)4, and Zr(On-C4H9)4 are preferred, with ZrCl4 being more preferred.

[0012] (B) Examples of organoaluminum compounds include those represented by general formula (III) and / or general formula (IV). AlY a X b O c N d (III) [In the formula, X represents a chlorine atom, a bromine atom, or an iodine atom; Y represents RO-, R2N-, -OCOR, or R-; R represents a linear or branched alkyl group with 1 to 20 carbon atoms; a, b, c, and d each independently represent an integer from 0 to 3, and a+b+c+d=3.]

[0013] Al2Y a’ X b’ O c’ N d’ (IV) [In the formula, X represents a chlorine atom, a bromine atom, or an iodine atom, and Y represents RO-, R2N-, -OCOR, -RCOCR'COR'', or R-. R, R', and R'' each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms. a', b', c', and d' each independently represent an integer from 0 to 6, and a'+b'+c'+d'=6.]

[0014] Examples of compounds represented by the general formula (III) include Al(CH3)3,Al(C2H5)3,Al(C3H7)3,Al(iso-C3H7)3,Al(C4H9)3,Al(iso-C4H9)3,Al(C5H 11 )3,Al(C6H 13 )3,Al(C8H 17)3,Al(C2H5)2Cl,Al(C2H5)2Br,Al(C2H5)2I,Al(C2H5)Cl2,Al(C2H5)Br2,Al(C2H5)I2,AlC2H5(OC2H5)2,AlC2H5(OC3H7)2,AlC2H5(OC 4H9)2,Al(OC2H5)2Cl,Al(OC3H7)2Cl,Al(OC4H9)2Cl,Al(OC2H5)Cl2,Al(OC3H7)Cl2,Al(OC4H9)Cl2,AlC2H5(OCOC2H5)2,AlC2H5(OCOC3 Examples include H7)2, AlC2H5(OCOC4H9)2, Al(OCOC2H5)2Cl, Al(OCOC3H7)2Cl, and Al(OCOC4H9)2Cl, Al(OCOC2H5)Cl2, Al(OCOC3H7)Cl2, Al(OCOC4H9)Cl2, Al(C2H5)2OC2H5, Al(C2H5)2OC3H7, Al(C2H5)2OC4H9, Al(C2H5)2(N(C2H5)2), Al(C2H5)2(N(C3H7)2), Al(C2H5)2N(C4H9)2, etc. Among these, Al(C2H5)3, Al(iso-C4H9)3, Al(C8H 17 )3 is preferred, and Al(C2H5)3 is more preferred.

[0015] Examples of compounds represented by the general formula (IV) include Al2(CH3)3Cl3, Al2(CH3)3Br3, Al2(C2H5)3Cl3, Al2(C2H5)3Br3, Al2(C2H5)3I3, Al2(C2H5)3BrCl2, Al2(C3H7)3Cl3, Al2(iso-C3H7)3Cl3, Al2(C4H9)3Cl3, Al2(iso-C4H9)3Cl3, Al2(C5H 11 )3Cl3,Al2(C8H 17 Examples include )3Cl3, Al2(C2H5)2(CH3)Cl3, Al2(OC2H5)3Cl3, Al2(OC3H7)3Cl3, Al2(OC4H9)3Cl3, Al2(OCOC2H5)3Cl3, Al2(OCOC3H7)3Cl3, and Al2(OCOC4H9)3Cl3. Among these, Al2(CH3)3Cl3, Al2(C2H5)3Cl3, and Al2(iso-C4H9)3Cl3 are preferred, and Al2(C2H5)3Cl3 is more preferred.

[0016] (C) The third component, which can be used as desired, may be at least one compound selected from the group consisting of sulfur compounds, phosphorus compounds, and nitrogen compounds. This third component contributes to improving the purity of the resulting α-olefin. The sulfur compound can be any organic sulfur compound and is not particularly limited, but for example, thioethers such as dimethyl sulfide, diethyl sulfide, dipropyl sulfide, dihexyl sulfide, dicyclohexyl sulfide, and diphenylthioether; dialkyl disulfide compounds such as dimethyl disulfide, diethyl disulfide, dipropyl disulfide, dibutyl disulfide, dihexyl disulfide, dicyclohexyl disulfide, and ethylmethyl disulfide; thiophenes such as thiophene, 2-methylthiophene, 3-methylthiophene, 2,3-dimethylthiophene, 2-ethylthiophene, and benzothiophene, heterocyclic sulfur compounds such as tetrahydrothiophene and thiopyran; aromatic sulfur compounds such as diphenyl sulfur, diphenyl disulfide, methylphenyl disulfide, and methylphenyl sulfur; thiourea; and sulfides such as methyl sulfide, ethyl sulfide, and butyl sulfide are preferably used.

[0017] As the phosphorus compound, any organophosphorus compound is acceptable and there are no particular restrictions, but phosphines such as triphenylphosphine, triethylphosphine, tributylphosphine, tripropylphosphine, trioctylphosphine, and tricyclohexylphosphine are preferably used. As the nitrogen compound, any organonitrogen compound is acceptable and there are no particular restrictions, but organic amines such as methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, cyclohexylamine, octylamine, decylamine, aniline, benzylamine, naphthylamine, dimethylamine, diethylamine, dibutylamine, diphenylamine, methylphenylamine, trimethylamine, triethylamine, tributylamine, triphenylamine, pyridine, and picoline are preferably used.

[0018] Among the sulfur compound, the phosphorus compound, and the nitrogen compound, one or more compounds selected from the group consisting of, for example, dimethyl disulfide, thiophene, thiourea, triphenylphosphine, tributylphosphine, trioctylphosphine, and aniline can be suitably used.

[0019] <Conditions for polymerization reaction, etc.> The polymerization reaction of ethylene is preferably carried out in an organic solvent. The amount of organic solvent used in the polymerization reaction of ethylene is preferably 0.5 to 5 times (by mass ratio) the amount of α-olefin produced. As the organic solvent, alicyclic compounds such as cyclohexane and decalin; aromatic hydrocarbons such as benzene, toluene, xylene, chlorobenzene, ethylbenzene, dichlorobenzene, and chlorotoluene, and their halides; aliphatic hydrocarbons such as pentane, hexane, heptane, octane, nonane, and decane; and halides of aliphatic hydrocarbons such as dichloroethane and dichlorobutane can be used. Among these, alicyclic compounds are preferred, and cyclohexane is more preferred.

[0020] In this process, the blending ratio of the transition metal compound (A) in the catalyst to the organic solvent is preferably 0.01 to 5 mmol, more preferably 0.03 to 1 mmol, of the transition metal compound (A) per 250 ml of organic solvent. The blending ratio of the organoaluminum (B) in the catalyst to the organic solvent is preferably 0.05 to 15 mmol, more preferably 0.06 to 3 mmol, of the organoaluminum (B) per 250 ml of organic solvent. The blending ratio of the third component (C) in the catalyst to the organic solvent is preferably 0.05 to 20 mmol, of the third component (C) per 250 ml of organic solvent, preferably 0.1 to 10 mmol when the sulfur compound is used as the third component (C), and preferably 0.05 to 5 mmol when a nitrogen compound or phosphorus compound is used as the component (C). Furthermore, the blending ratio of the transition metal compound (A) to the organoaluminum (B) is preferably set to an Al / Zr or Ti (molar ratio) in the range of 1 to 15. The mixing ratio [Al / Zr or Ti (molar ratio)] of (A) the transition metal compound and (B) the organoaluminum is more preferably 2 to 10, and even more preferably 4 to 9.

[0021] The polymerization reaction in this process is preferably carried out at a temperature of 100 to 150°C at a rate of 30 to 90 kg / cm³. 2 The process is carried out under pressure of G (2.94~8.82 MPa). The ethylene gas pressure is 30~90 kg / cm². 2 A pressure of G (2.94~8.82 MPa) is preferred, and the pressure is 50~80 kg / cm². 2 A pressure of 4.90 to 7.84 MPa is more preferable. The reaction time is affected by temperature and pressure and cannot be determined uniformly, but it is preferably 10 minutes or more, more preferably 30 minutes or more, more preferably 60 minutes or less, and more preferably 50 minutes or less. When using a continuous reactor, the residence time in the reactor is preferably 10 minutes or more, more preferably 30 minutes or more, more preferably 60 minutes or less, and more preferably 50 minutes or less. A fully mixed reactor type is preferred.

[0022] The reaction mixture after polymerization typically contains unreacted ethylene in addition to the reaction product, α-olefin. Before step 2, the ethylene and α-olefin may be separated from the reaction mixture to recover the unreacted ethylene. That is, a separation step may be provided to separate the reaction mixture containing the unreacted ethylene and α-olefin from the reaction mixture after polymerization to recover the unreacted ethylene. If such a separation step is provided, step 2 is provided with the reaction mixture containing the separated α-olefin. A flusher is preferably used for this separation step. Figure 1 shows a flusher 15 as an example of a device for recovering unreacted ethylene. In the flusher 15, the unreacted ethylene 16 is recovered from the top of the flusher. Furthermore, the separated and recovered unreacted ethylene may be recycled and used in the polymerization reaction of step 1. The unreacted ethylene recycled and used in the polymerization reaction of step 1 contains α-olefins that were not completely separated in the separation step. When such α-olefins are reused in the polymerization reaction, they induce side reactions in the polymerization reaction, producing by-products such as α-olefins with a branched structure. Therefore, it is preferable that the α-olefin content in the unreacted ethylene that is purified in a distillation column or the like and recycled in the polymerization reaction be 2% by mass or less. In step 2, the reaction mixture after the polymerization reaction may be used as is, or the reaction mixture obtained by removing unreacted ethylene from the reaction mixture after the polymerization reaction using the method described above may be used.

[0023] [Process 2] Step 2 is a step in which the reaction mixture obtained in Step 1 and the base are continuously introduced into a line mixer and mixed, with a stirring power of 30 to 1000 kW·sec / m 3 The number of passes is between 5 and 50. The catalyst is deactivated by mixing the reaction mixture with the base. Specifically, step 2 is a step in which the catalyst is deactivated by continuously introducing the reaction mixture obtained in step 1 and the base into a line mixer and mixing them, with a stirring power of 30 to 1000 kW·sec / m². 3 The number of passes is between 5 and 50.

[0024] In Figure 1, the reaction mixture obtained in reactor 1, containing the catalyst, solvent, and α-olefin, is continuously introduced into line mixer 5 via control valve 2, and further through confluence point 6 and line mixer inlet 7. A device such as a flusher 15 may be provided to recover unreacted ethylene contained in the reaction mixture before it is supplied to line mixer 5. Furthermore, a deactivating base (preferably ammonia) is continuously introduced into line mixer 5 as an aqueous solution from deactivating tank (ammonia water tank) 3 via pump 4, and further through confluence point 6 and line mixer inlet 7. The reaction mixture and base introduced into the line mixer 5 are mixed, deactivating the catalyst contained in the reaction mixture. The aforementioned line mixer is preferably equipped with a turbine (rotor) and a stator, and more preferably mixes by shear force in the gap between the turbine (rotor) and the stator. By using such a line mixer, the base and catalyst can be mixed and brought into contact in a small size and at high speed. A commercially available line mixer can be used. An example of a commercially available line mixer is the pipeline homomixer manufactured by Primix Corporation.

[0025] In this process, the stirring power of the line mixer is preferably 30 to 1000 kW·sec / m 3 It is more comfortable at 50-500 kW·s / m 3 And more preferably 100-300 kW·s / m 3 Therefore, 30 kW·s / m is recommended for sufficient mixing. 3 The above is preferable. 1000 kW·s / m is preferable from the viewpoint of suppressing mechanical load and heat generation. 3 The following is preferable. More preferably, from the viewpoint of thorough mixing, 150-300 kW·s / m 3 On the other hand, from the viewpoint of suppressing mechanical load and heat generation, a more preferable value is 100-150 kW·sec / m². 3Furthermore, if the reaction mixture and base being mixed contain an organic solvent and water, the stirring power should be 1000 kW·sec / m 3 The following steps can facilitate the separation of oil and water after mixing. Furthermore, the number of passes is preferably 5 to 50, more preferably 5 to 30, and even more preferably 5 to 20. 5 or more is preferable from the viewpoint of providing sufficient shear and mixing. 50 or less is preferable from the viewpoint of suppressing mechanical load and heat generation. By using the above-mentioned stirring power and number of passes, it is possible to sufficiently deactivate the catalyst while also shortening the time required for catalyst deactivation. In other words, by using a line mixer and mixing the reaction mixture and base with the above-mentioned stirring power and number of passes, catalyst deactivation can be performed efficiently, and side reactions can be suppressed, thereby reducing the formation of organic halogen compounds.

[0026] In this specification, stirring power refers to the power applied per unit volume of the processing liquid (a mixture of the reaction mixture and the base), and is expressed as power (P) [kW] in the stirring space and volumetric flow rate (Q) [m³]. 3 It is calculated from formula (1) based on [ / second]. Equation (1): Stirring power = P / Q [kW sec / m 3 ]

[0027] Furthermore, in this specification, the number of passes refers to the average number of shear cycles the processed fluid (a mixture of the reaction mixture and the base) undergoes while passing through the line mixer, and is defined by the rotational speed (n) [1 / sec] and blade diameter (d) [m] of the line mixer, and the volumetric flow rate Q [m³]. 3 It is calculated from equation (2) based on [ / second]. Equation (2): Number of passes = n·d 3 / Q

[0028] When multiple line mixers are installed in series, or when one line mixer has multiple stirring units in series, the stirring power in this embodiment shall be the sum of the stirring powers of each of those multiple configurations, and the number of passes shall be the sum of the number of passes of each of those multiple configurations. The number of configurations (the product of the number of line mixers installed in series and the number of stirring units in one line mixer) is preferably 4 or less, more preferably 3 or less, more preferably 2 or less, and even more preferably 1. When the above configurations are provided in parallel, the stirring power and number of passes in this embodiment shall be the values ​​for each individual unit.

[0029] In the production of α-olefins, using a line mixer as a mixer for deactivating the catalyst allows for high-speed mixing of the base and the catalyst. This suppresses side reactions that occur when water and the catalyst come into contact, and thus suppresses the formation of organic halogen compounds generated by these side reactions. Furthermore, in this invention, it is believed that the reaction can be controlled while the fluid is continuously passed through by adjusting not only the power but also the number of shear cycles when using the line mixer. Thus, by using a line mixer as a mixer for deactivating the catalyst, and further setting the stirring power and number of passes within the aforementioned range, it is believed that the catalyst can be continuously and sufficiently deactivated, suppressing the formation of organic halogen compounds, and efficiently producing α-olefins.

[0030] In this process, the reaction mixture and the base are continuously introduced into a line mixer and mixed, but they are brought into contact before being introduced into the line mixer. That is, this manufacturing method preferably includes a step of bringing the reaction mixture and the base into contact before continuously introducing the reaction mixture and the base into the line mixer. Furthermore, it is preferable that the distance from the confluence point where the reaction mixture and the base come into contact to the inlet of the line mixer is 1 m or less. This will be explained in detail below with reference to Figure 1. In Figure 1, the reaction mixture and the base come into contact at the confluence point 6, pass through the line mixer inlet 7, and are introduced into the line mixer 5. Here, the distance from the confluence point 6 where the reaction mixture and the base come into contact to the line mixer inlet 7 is preferably 1 m or less, more preferably 50 cm or less, and even more preferably 20 cm or less. When the distance from the confluence point where the reaction mixture and the base come into contact to the line mixer inlet is within the above range, the mixing of the base and the reaction mixture is carried out quickly and the catalyst in the reaction mixture can be deactivated, thereby suppressing side reactions that occur when moisture that may be contained in the base comes into contact with the catalyst, and thereby suppressing the by-product formation of organic halogen compounds generated by these side reactions. The mixture mixed in the line mixer 5 is discharged from the line mixer and then sent to the deasher 8 for the deashing process.

[0031] The base used in this process is preferably at least one selected from the group consisting of ammonia, amines, and alkali metal hydroxides, more preferably at least one selected from the group consisting of ammonia and amines, and even more preferably ammonia. Examples of amines include methylamine, ethylamine, propylamine, butylamine, pentylamine, hexylamine, cyclohexylamine, octylamine, decylamine, aniline, benzylamine, naphthylamine, dimethylamine, diethylamine, dibutylamine, diphenylamine, methylphenylamine, trimethylamine, triethylamine, tributylamine, triphenylamine, pyridine, and picoline. Examples of alkali metal hydroxides include sodium hydroxide and potassium hydroxide. Ammonia and amines are readily soluble in organic phases and can quickly come into contact with catalysts to deactivate them. In particular, ammonia has a small molecular weight, so it can efficiently deactivate catalysts even in small amounts. Furthermore, it is even more preferable to use ammonia or amines in combination with alkali metal hydroxides. Alkali metal hydroxides are strong bases and have the effect of raising the pH of the aqueous phase, which makes it easier to dissolve the aluminum salt produced by catalyst deactivation in the aqueous phase. The amount of base used is preferably 30 molar times or more relative to the halogen content in the catalyst, and more preferably 50 molar times or more. There is no upper limit, but it is preferably 150 molar times or less. These bases are preferably used as aqueous solutions. The base concentration of the aqueous solution is preferably 1 to 30% by mass, and more preferably 10 to 30% by mass. When the concentration of the aqueous solution is within this range, the by-product formation of organic halogen compounds can be further reduced.

[0032] When mixing the reaction mixture and the base in a line mixer, the mixing ratio of the solvent in the reaction mixture to the aqueous solution containing the base [solvent:aqueous solution containing the base] is preferably 1:10 to 100:1 (mass ratio), more preferably 1:1 to 100:1 (mass ratio), and even more preferably 5:1 to 20:1 (mass ratio).

[0033] The temperature during mixing (the temperature of the liquid in the line mixer) is preferably 90 to 150°C, and more preferably 100 to 130°C. Furthermore, it is preferable that the mixing pressure be such that no gas is generated in the line mixer. The mixing pressure is preferably 0.5 to 2.0 MPa (G), and more preferably 0.9 to 1.5 MPa (G).

[0034] [Steps 3 and 4] The manufacturing method of the present invention preferably further includes a deashification step 3 to remove the deactivated catalyst and a distillation step 4 to recover the α-olefin after step 2.

[0035] This will be explained in detail below with reference to Figure 1. The mixture mixed in step 2 is discharged from the line mixer 5 and then sent to the deasher 8 for the deashing process. In the deashing process, water 9 is added to the mixture and stirred to dissolve the deactivated catalyst in the water, thereby removing the catalyst from the mixture. Subsequently, the water containing the deactivated catalyst is separated in the oil-water separator 10, and the water containing the deactivated catalyst is discarded from the system as wastewater 11. The amount of water added in the deashification process is preferably 1 / 10 to 1 / 3 (by mass) of the oil phase (the mixture). The temperature during stirring is preferably 90°C to 150°C. The mixture, after undergoing the deashification process, is sent to the distillation system and subjected to distillation step 4. In the distillation system, if the mixture contains an organic solvent, the solvent is removed, and the target product, α-olefin, is recovered. Figure 1 shows an example of a distillation column. The mixture after the deashification process is introduced into the distillation column 12. From the top of the column, a liquid 13 mainly composed of low molecular weight α-olefins is obtained, and from the bottom of the column, a liquid 14 mainly composed of high molecular weight α-olefins and solvents is obtained. Each liquid can be fractionally distilled as needed to obtain α-olefins with a suitable number of carbon atoms (degree of polymerization) for the application.

[0036] The halogen content of the resulting α-olefin is preferably 2 ppm by mass or less, more preferably 1 ppm by mass or less, and even more preferably 0.5 ppm by mass or less. A halogen content of 2 ppm by mass or less is preferable because, when the α-olefin is used as a monomer or comonomer of various polyolefins, it does not adversely affect the catalyst used in the reaction when the α-olefin is reacted with other raw materials. Furthermore, the halogen content of α-olefins reflects the amount of organic halogen compounds contained in them; therefore, if the halogen content of an α-olefin is low, it can be said that the amount of organic halogen compounds contained in the α-olefin is also low. [Examples]

[0037] The present invention will be described in more detail below with reference to examples, but the present invention is not limited in any way by these examples.

[0038] Example 1 [Preparation of catalyst] The catalyst was prepared using the following procedure. Internal volume: 6.5 m³ 3 Dry cyclohexane was introduced into the stirred tank under a nitrogen atmosphere. Next, triethylaluminum [(C2H5)3Al] was introduced. Then, anhydrous zirconium tetrachloride [ZrCl4] was introduced. Next, ethylaluminum sesquichloride [(C2H5)3Al2Cl3] was introduced. The amounts of the raw materials and solvents were introduced as follows, based on anhydrous zirconium tetrachloride. Triethylaluminum and ethylaluminum sesquichloride were introduced so that (C2H5)3Al2Cl3 / (C2H5)3Al = 3.5 (molar ratio) and [(C2H5)3Al2Cl3+(C2H5)3Al] / ZrCl4 = 7 (molar ratio), and cyclohexane was introduced so that the concentration of anhydrous zirconium tetrachloride was 80 mmol per 1 L of cyclohexane. After adding all the components, the mixture was heated and stirred at 70°C for 2 hours under a nitrogen atmosphere to form a complex and prepare the catalyst solution.

[0039] [Step 1: Polymerization reaction] The reaction takes place in a fully mixed reactor (internal volume: approximately 20 m³). 3 The reaction was carried out continuously using reactor 1 (Figure 1). The reaction solvent (cyclohexane) was fed at a rate of 30 ton / hour, and the catalyst solution was fed at a rate of 25 kg / hour. The average residence time was approximately 45 minutes based on the solvent. The reaction was carried out at 130°C and 70 kg / cm³. 2 The reaction was carried out at G (6.9 MPa) with a stirring speed of 70 rpm. High-purity ethylene gas was also added at a reaction pressure of 70 kg / cm². 2 • Continuous supply was provided to maintain G. The reaction solution containing the polymerization reaction product (α-olefin) obtained from the polymerization reaction was introduced into a flusher (Figure 1: flusher 15), and gas-liquid separation was performed to obtain a reaction mixture consisting of a gaseous component containing unreacted ethylene and a liquid component containing the reaction product. This reaction mixture was used in step 2.

[0040] [Step 2: Deactivation step] The reaction mixture obtained in step 1 and 20% by mass aqueous ammonia are continuously supplied to a line mixer (product name: pipeline homomixer, manufactured by Primix Corporation) (Figure 1: line mixer 5) so that the mass ratio of reaction solvent to aqueous ammonia in the reaction mixture is 10:1, and the stirring power is 201 kW·sec / m 3 The catalyst was deactivated under the conditions of 6.9 passes and a temperature of 110°C. The flow velocity in the piping from the point where the reaction mixture and the ammonia water come into contact until they are introduced into the line mixer was approximately 1.2 m / s, and the distance until they are introduced into the line mixer (the distance from the confluence point 6 to the line mixer inlet 7 in Figure 1) was 15 cm.

[0041] [Process 3: Decalcification Process] The mixture discharged from the line mixer was transferred to a deasher (orifice mixer) (Figure 1: deasher 8) with water added in a mass ratio of reaction solvent:water = 3:1, and deashing was carried out at 110°C. The resulting mixture was sent to an oil-water separator (Figure 1: oil-water separator 10), and the oil phase was sent to the distillation system.

[0042] [Process 4: Distillation Process] In a distillation apparatus (Figure 1: distillation column 12, etc.), α-olefins with 4 to 24 carbon atoms were recovered by adjusting the distillation conditions as appropriate. The average halogen content of each α-olefin obtained was 0.5 ppm by mass or less.

[0043] Example 2 The stirring power is 141 kW·sec / m 3 α-olefins with various carbon number configurations were produced in the same manner as in Example 1, except that the number of passes was set to 6.1. The average halogen content of each α-olefin obtained was 0.5 ppm by mass or less.

[0044] Comparative Example 1 The stirring power is 46 kW·sec / m 3α-olefins of various carbon number configurations are produced in the same manner as in Example 1, except that the number of passes is set to 4.2. Due to insufficient mixing of the reaction mixture and the base, the average halogen content of each resulting α-olefin is 3 ppm by mass or more.

[0045] Comparative Example 2 Stirring power of 3 kW·sec / m 3 Except for setting the number of passes to 1.7, α-olefins with various carbon number configurations are produced in the same manner as in Example 1. Due to insufficient mixing of the reaction mixture and the base, the average halogen content of each resulting α-olefin is 3 ppm by mass or more. [Explanation of symbols]

[0046] 1: Reactor 2: Control valve 3: Inactivator tank (ammonia water tank) 4: Pump 5: Line Mixer 6: Confluence 7: Line mixer inlet 8: Deasher 10: Oil-water separation tank 12: Distillation column 15: Flasher

Claims

1. Step 1 involves continuously introducing ethylene and a catalyst into a reactor and carrying out a polymerization reaction to obtain a reaction mixture, and The process includes step 2 of continuously introducing the reaction mixture and the base into a line mixer and mixing them. The stirring power in the aforementioned line mixer is 30 to 1000 kW·s / m ３ A method for producing α-olefins, wherein the number of passes is 5 to 50.

2. A method for producing α-olefin according to claim 1, comprising the step of bringing the reaction mixture and the base into contact before continuously introducing the reaction mixture and the base into a line mixer, wherein the distance from the confluence point where the reaction mixture and the base come into contact to the inlet of the line mixer is 1 m or less.

3. The method for producing an α-olefin according to claim 1 or 2, wherein the catalyst is a Ziegler-type catalyst.

4. A method for producing an α-olefin according to any one of claims 1 to 3, wherein the base is ammonia.

5. A method for producing α-olefin according to any one of claims 1 to 4, further comprising a deashification step 3 for removing the deactivated catalyst and a distillation step 4 for recovering the α-olefin after step 2.

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