JP3351068B2 - Method for producing α-olefin low polymer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an α-olefin low polymer, and more particularly, to a method for producing an α-olefin low polymer mainly composed of 1-hexene from ethylene in a high yield. The present invention relates to an industrially advantageous method for producing an α-olefin low polymer which can be produced at a high selectivity.

[0002]

2. Description of the Related Art Heretofore, as a method for low polymerization of an α-olefin such as ethylene, a method using a chromium catalyst comprising a combination of a specific chromium compound and a specific organic aluminum compound has been known. For example, Japanese Patent Publication No. 43-1
No. 8707 describes a method for obtaining 1-hexene from ethylene by a catalyst system represented by the general formula MXn and comprising a chromium-containing group VIA transition metal compound (M) and polyhydrocarbyl aluminum oxide (X). ing.

JP-A-3-128904 discloses that an α-olefin is trimerized using a catalyst obtained by previously reacting a chromium-containing compound having a chromium-pyrrolyl bond with a metal alkyl or Lewis acid. A method is described.

On the other hand, as a method for producing a poly-α-olefin and a method for producing an α-olefin dimer, a method using a catalyst containing a compound represented by the general formula (1) or (2) used in the present invention. It has been known.

[0005] For example, JP-A-4-328110 discloses a catalyst comprising (a) a transition metal compound, (b) an organometallic compound, and (c) a compound which reacts with the transition metal compound to form an ionic compound. It is described that a poly-α-olefin having a sufficiently large molecular weight can be produced by reacting the compound with an α-olefin.

Further, Japanese Patent Application Laid-Open No. 5-39229 discloses that
By reacting an α-olefin having a cyclic hydrocarbon group with a catalyst comprising (A) a transition metal compound, (B) an organoaluminum compound, and (C) a compound comprising a cation and an anion having a plurality of groups bonded to elements. It describes that an α-olefin dimer can be produced.

[0007]

However, in the method described in JP-B-43-18707, under the condition that the amount of polyethylene by-produced simultaneously with 1-hexene is large and the amount of polyethylene by-produced is reduced, There is a problem in that the catalytic activity is reduced, and a large amount of expensive polyhydrocarbyl aluminum oxide is required as a catalyst component. Further, the method described in JP-A-3-128904 has a problem that the by-product polymer such as polyethylene is small, but the catalytic activity is not sufficient.

The present invention has been made in view of the above-mentioned circumstances, and has as its object to provide an industrially advantageous method for producing α-hexene such as 1-hexene.
An object of the present invention is to provide a method for producing an α-olefin low polymer which can produce an olefin low polymer with high yield and high selectivity.

[0009]

The present inventors have conducted intensive studies to achieve the above object, and as a result, if a specific chromium-based catalyst is used, a low polymerization reaction of α-olefin, especially ethylene It has been found that a low polymerization reaction mainly involving trimerization of hexene proceeds with extremely high activity to produce hexene having a high purity of 1-hexene.

The present invention has been completed based on the above findings, and the gist of the present invention is to provide a method for producing an α-olefin low polymer by low-polymerizing an α-olefin in the presence of a chromium-based catalyst. , As a chromium-based catalyst, at least
Production of an α-olefin low polymer using a catalyst system comprising a combination of a chromium compound, an amine or metal amide, an alkylaluminum compound, and a compound represented by the following general formula (1) or (2) Be in the way.

Embedded image

Embedded image (Wherein M ¹ and M ² are groups IIIB and IVB of the periodic table)
R ^{1 to} R ⁷ , an element selected from group VV, group VB and group VIB;
Represents an organic group, an inorganic group or a negative atom, and [L] ⁺ represents groups IA, VIIA, VIII, IB, and IIIB of the periodic table.
And a cation containing an element selected from Group VIB. )

Hereinafter, the present invention will be described in detail. The chromium compound used in the present invention is represented by the general formula CrXn.
However, in the general formula, X represents any organic or inorganic group or a negative atom, n represents an integer of 1 to 6, and n
Is 2 or more, X may be the same or different from each other. The valence of chromium is from 0 to 6, and n in the above formula is preferably 2 or more.

Examples of the organic group include various groups having usually 1 to 30 carbon atoms. Specific examples include a hydrocarbon group, a silicon-substituted alkyl group, a carbonyl group, an alkoxy group, a carboxyl group, a β-diketonate group, a β-ketocarboxyl group, a β-ketoester group, and an amide group.

Examples of the hydrocarbon group include an alkyl group, a cycloalkyl group, an aryl group, an alkylaryl group, an aralkyl group, a cyclopentadienyl group, and an alkyl-substituted cyclopentadienyl group. Examples of the inorganic group include a chromium salt-forming group such as a nitrate group and a sulfate group.
Examples of the negative atom include oxygen and halogen.

As the chromium compound, a compound soluble in a hydrocarbon solvent is preferable, and a chromium alkoxy salt, a carboxyl salt, a carboxylate, a β-diketonate salt, a salt with an anion of β-keto ester, a halide, or
Amide complex, alkyl complex, phenyl complex, carbonyl complex, carbene complex, cyclopentadienyl complex, silicon-substituted alkyl complex, specifically, chromium (IV) te
rt-butoxide, chromium (II) acetate, chromium (III)
Acetate, chromium (III) 2-ethylhexanoate,
Chromium (III) benzoate, chromium (III) naphthenate, chromium (III) acetylacetonate, chromium (III)
Trifluoroacetylacetonate, chromium (III) hexafluoroacetylacetonate, chromium (III) (2,
2,6,6-tetramethyl-3,5-heptanedionate), Cr (PhCOCHCOPh) ₃ (where P
h represents a phenyl group. ), Cr (CH ₃ COCHCO)
OCH ₃ ) ₃ , chromium chloride, chromium chloride, chromium bromide, chromium bromide, chromium iodide, chromium iodide, chromium fluoride, chromium fluoride ,
(CH ₃ ) ₄ Cr, (CH ₃ ) ₂ CrCl, Cr (C
_{O) 6, (C 6 H} 6) Cr (CO) 3, (CO) 5 Cr
(= CCH ₃ (OCH ₃ )), (CO) ₅ Cr (= CC
₆ H ₅ (OCH ₃ )), Cp ₂ Cr, CpCrCl
₂ (where Cp represents a cyclopentadienyl group),
_{(Cp * CrClCH 3) 2,} Cp * 2 Cr ( here Cp
* Represents a pentamethylcyclopendienyl group. ), Tetrakis (trimethylsilyl) chromium and the like.

Also, a complex comprising the above chromium compound and an electron donor can be suitably used. The electron donor is selected from compounds containing nitrogen, oxygen, phosphorus or sulfur.

Examples of the nitrogen-containing compound include nitrile, amine, amide and the like. Specifically, acetonitrile, pyridine, dimethylpyridine, dimethylformamide, N-methylformamide, aniline, nitrobenzene, tetramethylethylenediamine, diethylamine,
Isopropylamine, hexamethyldisilazane, pyrrolidone and the like.

Examples of the oxygen-containing compound include esters, ethers, ketones, alcohols and aldehydes.
Specific examples include ethyl acetate, methyl acetate, tetrahydrofuran, dioxane, diethyl ether, dimethoxyethane, diglyme, triglyme, acetone, methyl ethyl ketone, methanol, ethanol, acetaldehyde and the like.

Examples of the phosphorus-containing compound include hexamethylphosphoramide, hexamethylphosphorustriamide, triethylphosphite, tributylphosphine oxide, and triethylphosphine. On the other hand, examples of the sulfur-containing compound include carbon disulfide, dimethyl sulfoxide, tetramethylene sulfone, thiophene, and dimethyl sulfide.

Therefore, the chromium compound and the electron donor
Examples of such complexes include ether complexes of chromium halides,
Ester complex, ketone complex, aldehyde complex, alcohol
Complexes, amine complexes, nitrile complexes, phosphine complexes,
Thioether complexes and the like. Specifically, Cr
Cl_Three・ 3THF, CrCl_Two・ 2THF, CrCl _Three
・ 3dioxane, CrCl_Three・ (CH_ThreeCO_Twon-
C_FourH₉), CrCl _Three・ (CH_ThreeCO_TwoC_TwoH_Five),
CrCl_Three・ 3 (i-C_ThreeH₇OH), CrCl_Three・ 3
[CH_Three(CH_Two)_ThreeCH (C_TwoH_Five) CH_TwoOH],
CrCl_Three・ 3pyridine, CrCl_Two・ 2py
ridine, CrCl_Three・ 2 (i-C _ThreeH₇N
H_Two), CrCl_Two・ 2 [(C_TwoH_Five)_TwoNH], [Cr
Cl_Three・ 3CH_ThreeCN] ・ CH_ThreeCN, CrCl_Two・ 2
CH_ThreeCN, CrCl_Three・ 3PPh_Three, CrCl_Two・ 2
[P (CH_Three)_TwoPh], CrCl_Three・ 3thioph
ene, CrCl_Two・ 2thiophene etc.
It is.

The chromium compound can also be used by being supported on a carrier, such as SiO ₂ , Al ₂ O ₃ , Zr
Examples include inorganic oxides such as O ₂ and MgO, inorganic phosphates such as ZrPO ₄ and AlPO ₄ , and magnesium halides such as MgCl _{2. In} the present invention, other catalysts are used without being supported on a carrier. It is preferred to use in combination with the components. That is, in the present invention, a chromium-based catalyst composed of a combination of specific catalyst components is used. If such a chromium-based catalyst is used, a high catalytic activity can be obtained without carrying a chromium compound on a carrier. . And
When the chromium compound is used without being supported on a carrier, it is not necessary to support the carrier with complicated operations, and the total amount of the catalyst used (the total amount of the carrier and the catalyst component).
The problem of an increase in the number can also be avoided.

The amine used in the present invention may be primary or secondary.
Grade amines or mixtures thereof. Examples of the primary amine include ammonia, ethylamine, isopropylamine, cyclohexylamine, benzylamine, aniline, and naphthylamine. Examples of the secondary amine include diethylamine, diisopropylamine, dicyclohexylamine, dibenzylamine, and bis (trimethylsilyl) amine. , Morpholine, imidazole, indoline, indole, pyrrole, 2,5-dimethylpyrrole, 3,4-dimethylpyrrole, 3,4-dichloropyrrole, 2,3,4,5-tetrachloropyrrole, 2-acylpyrrole, pyrazole , Pyrrolidine and the like. In the present invention, a secondary amine is preferably used,
In particular, pyrrole, 2,5-dimethylpyrrole, 3,4-
Dimethylpyrrole, 3,4-dichloropyrrole, 2,
3,4,5-Tetrachloropyrrole and 2-acylpyrrole are preferred.

The metal amide used in the present invention is a metal amide derived from a primary or secondary amine, or a mixture thereof. Specifically, a primary or secondary amine and a group IA, IIA Amides obtained by reaction with a metal selected from Group III, Group IIIB and Group IVB. Specific examples of such metal amides include lithium amide, sodium ethylamide, calcium diethylamide, lithium diisopropylamide, potassium benzylamide, sodium bis (trimethylsilyl) amide, lithium indolide, sodium pyrrolide, lithium pyrrolide, and potassium pyrrole. Ride, potassium pyrrolidide, aluminum diethylpyrrolide, ethylaluminum dipyrrolide, aluminum tripyrolide and the like. In the present invention, metal amides derived from secondary amines are preferably used. In particular, diethylaluminum pyrrolide, ethylaluminum dipyrrolide, aluminum tripyrolide, sodium pyrrolide, lithium pyrrolide, potassium pyrrolide Is preferred.

The chromium compound and amine or metal amide used in the present invention may be used after being converted into, for example, a chromium compound having a chromium-pyrrolyl bond by performing a pretreatment described below in advance. The chromium compound having a chromium-pyrrolyl bond can be obtained by reacting the chromium compound exemplified above with pyrrole or metal pyrrolide in a solvent. The metal pyrrolide refers to a compound synthesized from pyrrole and a derivative of pyrrole. As the pyrrole derivative, 2,5-dimethylpyrrole, 3,4-dimethylpyrrole, 3,4-dichloropyrrole, 2,3,4,5 -Tetrachloropyrrole, 2-acylpyrrole, and the like;
Selected from Group IA, Group IIIB and Group IVB. Preferred metal pyrrolides include lithium pyrrolide, sodium pyrrolide, potassium pyrrolide, cesium pyrrolide and the like.

In the present invention, as the alkylaluminum compound, an alkylaluminum compound represented by the following general formula (3) is preferably used.

[Image Omitted] R ¹ _m Al (OR ² ) _{n Hp} X _q (3)

In the formula, R ¹ and R ² usually have 1 to 1 carbon atoms.
15, preferably 1 to 8 hydrocarbon groups, which may be the same or different, X represents a halogen atom, m is 0 <m ≦ 3, n is 0 ≦ n <3, p Is 0 ≦ p <
3, q is each number of 0 ≦ q <3, and
Represents a number where m + n + p + q = 3.

Examples of the above alkylaluminum compound include a trialkylaluminum compound represented by the following general formula (4), an alkylaluminum halide compound represented by the following general formula (5), and an alkoxyaluminum compound represented by the following general formula (6). Aluminum compounds, alkyl aluminum hydride compounds represented by the general formula (7), and the like can be given. The meanings of R ¹ , X and R ² in each formula are the same as described above.

[0027]

Embedded image _{^{R 1 3 Al ··· (4)}} R 1 m AlX 3-m (m is 1. 5 ≦ m <3) ··· (5) R 1 m Al (OR 2) 3-m ( m is 0 <m <3, preferably 1.5 ≦ m <3) (6) R ¹ _m AlH _3-m (7) (m is 0 <m <3, preferably 1. 5 ≦ m <3)

Specific examples of the above alkylaluminum compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, diethylaluminum monochloride, diethylaluminum ethoxide, diethylaluminum hydride and the like. Of these, trialkylaluminum is particularly preferred in that it produces less polymer by-products.

The compound represented by the general formula (1) or (2) used in the present invention means a compound containing a non-coordinating Lewis acid,

Embedded image

Embedded image And hereinafter referred to as “compound (1) or (2)”.

In the formula, M ¹ and M ² represent IIIB of the periodic table.
Group, IVB group, VB group, and VIB group. As M ¹ and M ² , B, Al, In and the like are particularly preferably used.

R ^{1 to} R ⁷ are an organic group, an inorganic group, or a negative atom, such as a hydrogen atom, a dialkylamino group,
0 alkoxy group, C6-C20 aryloxy group, C1-C20 alkyl group, C6-C20 aryl group, alkylaryl group, arylalkyl group, C1-C20 halogen-substituted carbon Hydrogen group, carbon number 1-2
0, an acyloxy group having 1 to 20 carbon atoms, an alkoxyaryl group having 1 to 20 carbon atoms, a halogen-substituted alkoxyaryl group having 1 to 20 carbon atoms, an organic metalloid group, or a halogen atom. It may form a ring.

As R ^{1 to} R ⁷ , specifically, dimethylamino, diethylamino, pyrrolyl, 2,5-dimethylpyrrolyl, methoxy, ethoxy, isopropoxy, n-butoxy, t-butoxy group, phenoxy group, 2,6-dimethylphenoxy group, 2,6-t-butylphenoxy group, naphthylphenoxy group, methyl group,
Ethyl group, n-propyl group, n-butyl group, n-octyl group, phenyl group, 3-methylphenyl group, 2,4-dimethylphenyl group, 2,6-dimethylphenyl group, 3,
5-dimethylphenyl group, 2,3-dimethylphenyl group, 2,4,6-trimethylphenyl group, 2,3,5-
Trimethylphenyl group, 2,3,4-trimethylphenyl group, 3-t-butylphenyl group, 2,6-di-t-butylphenyl group, benzyl group, p-fluorophenyl group, 3,5-difluorophenyl group Pentachlorophenyl group, 3,4,5-trifluorophenyl group, pentafluorophenyl group, 3,5-di (trifluoromethyl) phenyl group, 3-methoxyphenyl group, 2,4-dimethoxyphenyl group, 2, 6-dimethoxyphenyl group,
3,5-dimethoxyphenyl group, 2,3-dimethoxyphenyl group, 2,4,6-trimethoxyphenyl group, 2,
3,5-trimethoxyphenyl group, 2,3,4-trimethoxyphenyl group, 3,5-bis (1-methoxy-2,
2,2-trifluoro-1- (trifluoromethyl) ethyl) phenyl group, 3- (1-methoxy-2,2,2-
Trifluoro-1- (trifluoromethyl) ethyl)-
5- (trifluoromethyl) phenyl group, 3- (2,
2,2-trifluoro-1- (2,2,2-trifluoroethoxy) -1- (trifluoromethyl) ethyl)-
5- (trifluoromethyl) phenyl group, 3,5-bis (2,2,2-trifluoro-1- (2,2,2-trifluoroethoxy))-1- (trifluoromethyl) ethyl) phenyl Group, trimethylsilyl group, trimethylgermyl group, diphenylarsine group, dicyclohexylantimony group, pentafluorotelluroxy group, F, C
l, Br, I and the like.

[L] of the general formula (1)⁺Is the IA of the periodic table
, VIIA, VIII, IB and IIIB ~
Shows a cation containing an element selected from Group VIB. L
Is M ^Three, M^FourR⁸R⁹, E¹R^TenR¹¹R¹²Or E^TwoR¹³R¹⁴
R^FifteenR¹⁶And M^ThreeIs the IA of the periodic table
M, an element selected from group III, group IB and group IIIB^FourIs V
An element selected from the group IIA and the group VIII, E¹Is carbon
Atom, oxygen atom or sulfur atom, E^TwoIs a nitrogen atom or phosphorus
Indicates an atom.

As M ³ , Li, Na, K, Ag
Etc., in particular Mn, Fe, Co, Ni or the like is preferably used as M ^4.

R ⁸ and R ⁹ are substituents selected from a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl group and a fluorenyl group, and may be bonded to each other to form a ring. The substituent of the substituted cyclopentadienyl group of R ⁸ and R ⁹ is usually an alkyl group having 1 to 6 carbon atoms, and the number of the substituent is an integer of 1 to 5. Specific examples include a methylcyclopentadienyl group, an n-butylcyclopentadienyl group, and a pentamethylcyclopentadienyl group.

R ^{10 to} R ¹⁶ are selected from a hydrogen atom, a halogen atom, an alkyl group having 1 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, an alkylaryl group, an arylalkyl group, and an organic metalloid group. Yes, specifically, hydrogen, methyl, ethyl, n-propyl, n-
Methyl group, n-octyl group, cyclohexyl group, phenyl group, benzyl group, 3-methylphenyl group, 2,4-dimethylphenyl group, 2,6-dimethylphenyl group, 3,
5-dimethylphenyl group, 2,3-dimethylphenyl group, 2,4,6-trimethylphenyl group, 2,3,5-
Trimethylphenyl group, 2,3,4-trimethylphenyl group, 3-t-butylphenyl group, 2,6-di-t-butylphenyl group, F, Cl, Br, I and the like.

Among the compounds (1) and (2), those in which M ¹ or M ² is boron are particularly preferred, and among the compounds (1), the following are particularly preferred.

Compounds wherein L is M ³ include silver tetraphenylborate, sodium tetraphenylborate, silver tetrakis (pentafluorophenyl) borate, lithium tetrakis (pentafluorophenyl) borate,
Silver tetrakis (pentafluorotelluryloxy) borate, silver tetrafluoroborate, silver tetrafluoroarsenate, silver tetrafluoroantimonate and the like can be mentioned.

Compounds wherein L is M ⁴ R ⁸ R ⁹ include tetraphenylborate ferrocenium, tetraphenylborate manganese (tetraphenylporphyrin), tetrakis (petafluorophenyl) borate ferrocenium, tetrakis (pentafluorophenyl) Examples include borate decamethylferrocenium, tetrakis (pentafluorophenyl) borate acetylferrocenium, tetrakis (pentafluorophenyl) borate formylferrocenium, and tetrakis (pentafluorophenyl) borate cyanoferrocenium.

Compounds in which L is E ¹ R ¹⁰ R ¹¹ R ¹² include:
Examples include tetraphenylborate trityl, tetrakis (pentafluorophenyl) borate trityl, tetraphenylborate methylsulfonium, tetraphenylboratebenzyldimethylsulfonium, and tetrakis (pentafluorophenyl) boratebenzyldimethylsulfonium.

Compounds wherein L is E ² R ¹³ R ¹⁴ R ¹⁵ R ¹⁶ include tetraphenylborate ammonium, tetraphenylborate triethylammonium, tetraphenylborate tri (n-butyl) ammonium, tetraphenylborate trimethylammonium, tetraphenylborate Borate pyrrolium, tetraphenylborate 2,5
-Dimethylpyrrolinium, tetrakis (pentafluorophenyl) borate ammonium, tetrakis (pentafluorophenyl) borate triethylammonium,
Tetrakis (pentafluorophenyl) borate tri (n-butyl) ammonium, tetrakis (pentafluorophenyl) boratetrimethylammonium, tetrakis (penfluorophenyl) borateanilinium, tetrakis (pentafluorophenyl) borate monomethylanilinium, tetrakis (pentafluorophenyl) ) Borate dimethylanilinium, tetrakis (pentafluorophenyl) borate tetraphenylphosphonium, tetrakis (pentafluorophenyl) borate tetrabutylammonium, tetrakis (pentafluorophenyl) borate methyldiphenylammonium, tetrakis (pentafluorophenyl) borate triphenylammonium, Tetrakis (pentafluorophenyl) borate Jiniumu, tetrakis (pentafluorophenyl) borate dimethyl (m-nitro anilinium), tetrakis (pentafluorophenyl)
Borate dimethyl (p-bromoanilinium), tetrakis (pentafluorophenyl) borate (p-cyanopyridinium), tetrakis (pentafluorophenyl) borate trimethylanilinium, tetrakis (pentafluorophenyl) borate (N-methylpyridinium), tetrakis (Pentafluorophenyl) borate trimethylsulfonium, tetrakis (pentafluorophenyl) borate (o-cyano-N-methylpyridinium), tetrakis (pentafluorophenyl) borate dimethyldiphenylammonium, tetrakis

(Pentafluorophenyl) borate (p
-Cyano-N-benzylpyridinium), tetrakis (pentafluorophenyl) borate methyltriphenylammonium, tetrakis (pentafluorophenyl) boratepyrrolinium, tetrakis (pentafluorophenyl) borate 2,5-dimethylpyrrolinium,
Tetrakis (3,5-di (trifluoromethyl) phenyl) borate dimethylanilinium, triethylammonium hexafluoroarsenate, tetrakis (3,5-bis (1-methoxy-2,2,2-trifluoro-1-)
(Trifluoromethyl) ethyl)) phenylborate dimethylanilinium, tetrakis (3- (1-methoxy-2,2,2-trifluoro-1- (trifluoromethyl) ethyl) -5- (trifluoromethyl)) Phenylborate dimethylanilinium, tetrakis (3-
(2,2,2-trifluoro-1- (2,2,2-trifluoroethoxy) -1- (trifluoromethyl) ethyl) -5- (trifluoromethyl)) phenylborate dimethylanilinium, tetrakis ( 3,5-bis (2,2,2-trifluoro-1- (2,2,2-trifluoroethoxy) -1- (trifluoromethyl) ethyl) phenylborate dimethylanilinium, tetraphenylborate tetraethylammonium, Tetraphenylborate methyltri (n-butyl) ammonium,
Tetraphenylborate benzyl tri (n-butyl) ammonium, tetraphenylborate trimethylanilinium, tetraphenylborate dimethyldiphenylammonium, tetraphenylborate methyltriphenylammonium, tetraphenylborate methylpyridinium, tetraphenylborate benzylpyridinium, tetraphenylboratemethyl (2-cyanopyridinium), tetrakis (pentafluorophenyl) borate (tetraethylammonium), tetrakis (pentafluorophenyl) borate (methyltri (n-butyl) ammonium), tetrakis (pentafluorophenyl) borate (benzyltri (n-butyl) Ammonium), tetrakis (pentafluorophenyl) borate methyl (4-sia Pyridinium), tetrakis (pentafluorophenyl) borate benzyl pyridinium, and the like.

Among the compounds (2), specifically, tris (pentafluorophenyl) boron, tris (3,5
-Bis (1-methoxy-2,2,2-trifluoro-1
-(Trifluoromethyl) ethyl)) phenylboron,
Tris 3- (1-methoxy--2,2,2-trifluoro-1- (trifluoromethyl) ethyl) -5- (trifluoromethyl)) phenylboron, tris (3-
(2,2,2-trifluoro-1- (2,2,2-trifluoroethoxy) -1- (trifluoromethyl) ethyl) -5- (trifluoromethyl)) phenylboron,
Tris (3,5-bis (2,2,2-trifluoro-1
-(2,2,2-trifluoroethoxy) -1- (trifluoromethyl) ethyl) phenylboron, triphenylboron, tris (pentafluorotelluroxy) boron and the like are particularly preferred.

In the present invention, the chromium-based catalyst comprising these chromium compound, amine or metal amide, alkylaluminum compound and compound (1) or (2) becomes an active species to cause low polymerization of α-olefin. Although the action of the compound (1) or (2) in the present invention is not clear at present, as described above, the compound (1) or (2) has been known to be highly active with α-olefins. There are facts that have been used for the purpose of obtaining polymers or dimers of α-olefins with high selectivity. On the other hand, despite the use of the compound (1) or (2) in the present invention, poly-α-olefin and α-olefin having a sufficiently large molecular weight are used.
Considering the experimental fact that the amount of olefin dimer formed is small and the α-olefin trimerization reaction is selectively proceeding, the compound (1) or (2) is activated by the catalytically active species or its precursor. It is considered to be contributing

In the present invention, the low polymerization of the α-olefin is carried out in a solvent using a catalyst system comprising the above-mentioned catalyst components, but the α-olefin is so contacted that the chromium compound and the alkylaluminum compound do not come into contact in advance. And a chromium-based catalyst to cause low polymerization of the α-olefin. By using such a specific contact mode,
By selectively performing a trimerization reaction, 1-hexene can be obtained in high yield from the raw material ethylene.

The specific contact mode described above is, specifically,
When an “amine or metal amide” is represented by an amine, a method of introducing an α-olefin and a chromium compound into a solution containing an amine, an alkylaluminum compound and the compound (1) or (2); A method for introducing an α-olefin and an alkylaluminum compound into a solution containing 1) or (2) and an amine, an α-olefin, an amine, a solution containing a chromium compound and a compound (1) or (2). And a method of introducing an alkylaluminum compound, a method of introducing an α-olefin, an amine, and a chromium compound into a solution containing the alkylaluminum compound and the compound (1) or (2); , Α-olefin, alkylaluminum compound, and compound (1)
Or a method of introducing (2), in a solution containing an alkylaluminum compound and an amine, an α-olefin, a chromium compound, and a compound (1).
Or a method of introducing (2), a method of introducing an α-olefin, a chromium compound, an amine, and a compound (1) or (2) in a solution containing an alkylaluminum compound, and a method of introducing a compound in a solution containing a chromium compound (1) or (2), a method of introducing an α-olefin, an amine, and an alkylaluminum compound, a chromium compound, an amine, an alkylaluminum compound, a compound (1) or (2), and an α-olefin simultaneously and independently; A method of introducing the compound into the reaction system is conceivable.

Even when a solution containing a chromium compound, an alkylaluminum compound, and the compound (1) or (2) is prepared before starting the low polymerization reaction, either one of the chromium compound and the alkylaluminum compound is prepared. Is contacted with the compound (1) or (2) in advance, and then the chromium compound is contacted with the alkylaluminum compound, whereby the above-mentioned contact mode is maintained.

In the present invention, "an embodiment in which the chromium compound and the alkylaluminum compound do not come into contact in advance"
Means not only at the beginning of the reaction, but additional α-
This means that such an aspect is maintained even when the olefin and the catalyst component are supplied to the reactor.

The reason why the activity of the low polymerization reaction of the α-olefin is reduced when a chromium-based catalyst is used in such a manner that the chromium compound and the alkylaluminum compound are brought into contact in advance is not clear, but is presumed as follows. Is done.

That is, when the chromium compound is brought into contact with the alkyl aluminum, it is considered that a ligand exchange reaction proceeds between the ligand coordinated to the chromium compound and the alkyl group in the alkyl aluminum compound. The alkyl-chromium compound produced by such a reaction is unstable in itself, unlike the alkyl-chromium compound obtained by a usual method. Therefore, alkyl-
The decomposition-reduction reaction of the chromium compound proceeds preferentially, and as a result, unsuitable demetalation occurs in the low polymerization reaction of the α-olefin, and the activity of the low polymerization reaction of the α-olefin decreases.

In the present invention, a substituted or unsubstituted α-olefin having 2 to 30 carbon atoms is used as the starting α-olefin. Specific examples include ethylene, propylene, 1-butene, 1-hexene, 1-octene, 3-methyl-1-butene, 4-methyl-1-pentene, and the like. In particular, ethylene is preferable as the raw material α-olefin, and 1-hexene, a trimer thereof, can be obtained from ethylene with high yield and high selectivity.

The solvents used in the present invention include:
Linear or alicyclic saturated hydrocarbons such as butane, pentane, hexane, heptane, octane, cyclohexane, methylcyclohexane, and decalin; aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene, mesitylene, and tetralin; chloroform; Chain chlorinated hydrocarbons such as carbon tetrachloride, methylene chloride, dichloroethane, trichloroethane, and tetrachloroethane, and chlorinated aromatic hydrocarbons such as chlorobenzene and dichlorobenzene are used. These can be used alone or as a mixed solvent.

As the solvent, α-olefin itself as a reaction raw material or α-olefin other than the main raw material can be used. For a solvent, the carbon number is 4-30.
Α-olefins are used, and α-olefins which are liquid at room temperature are particularly preferred. Particularly, a linear saturated hydrocarbon is preferable as the solvent.

In the present invention, the amount of the chromium compound to be used is usually 1.0 × 10 ^{−7 to} 0.
5 mol, preferably 1.0 × 10 ^{−6 to} 0.2 mol,
More preferably, it is in the range of 1.0 × 10 ^{−5 to} 0.05 mol. On the other hand, the amount of the alkylaluminum compound used is usually 50 mmol per 1 mol of the chromium compound.
As described above, from the viewpoints of catalytic activity and trimer selectivity, the amount is preferably 0.1 mol or more. And the upper limit is usually 1.0 × 10 ⁴ mol. The amount of the amine or metal amide used is usually 0.001 mol or more, preferably 0.1 mol / mol of the chromium compound.
005 to 1000 mol, more preferably 0.01 to 1
The range is 00 mol. The amount of the compound represented by the general formula (1) or (2) is usually 0.001 mol or more per 1 mol of the chromium compound,
Preferably it is in the range of 0.005 to 1000 mol, more preferably 0.01 to 100 mol.

The reaction temperature in the present invention is usually from 0 to 25.
0 ° C., preferably 0 to 150 ° C. The reaction pressure can be selected from the range of normal pressure to 250 kg / cm ² , but a pressure of 100 kg / cm ² is usually sufficient. The residence time is usually in the range of 1 minute to 20 hours, preferably 0.1 to 6 hours. The reaction system may be any of a batch system, a semi-batch system, and a continuous system, and it is preferable to coexist with hydrogen during the reaction, since the improvement in the catalytic activity is observed.

In the present invention, since the by-product polymer has a powdery form, it can be separated and removed much more easily than the conventional separation of a molten polymer. In addition, since the by-product polymer can be prevented from adhering to the inner wall of the process pipe, problems such as blockage of the pipe and a decrease in heat transfer coefficient can be avoided. Recovered α-
The olefin low polymer is purified as necessary, and the purification is usually carried out by distillation, and the target component can be recovered with high purity. In the present invention, in particular, hexene having a high purity of 1-hexene can be industrially advantageously produced from ethylene.

[0057]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist.

Example 1 A 300 ml autoclave heated and dried in a drier at 150 ° C. was assembled while hot, and then replaced with vacuum nitrogen. The autoclave was equipped with a catalyst feed tube equipped with a rupture disk. n-heptane (45 ml), a solution of triethylaluminum (0.400 mmol) in n-heptane, and a solution of pyrrole (0.060 mmol) in n-heptane were charged in this order on the barrel side of the autoclave, while the catalyst feed tube was charged with n-heptane. (III) solution
2-ethylhexanoate (10 mg, 0.021 mm
ol) and trispentafluorophenylboron B (C ₆
F ₅ ) ₃ (10 mg, 0.020 mmol) was charged.
The total amount of n-heptane was 50 ml.

First, the autoclave was heated to 100 ° C., and then ethylene was introduced at 100 ° C. from the catalyst feed tube. The rupture disk ruptured due to ethylene pressure, and a chromium compound was introduced into the autoclave barrel side to initiate low polymerization of ethylene. Ethylene was introduced until the total pressure reached 35 Kg / cm ² , after which the total pressure was maintained at 35 Kg / cm ² and the temperature was maintained at 100 ° C. After 15 minutes, ethanol was injected into the autoclave to stop the reaction.

After degassing by releasing the pressure of the autoclave, a by-product polymer (mainly polyethylene) in the reaction solution was separated and removed by filtration to recover an α-olefin low polymer. Table 1 shows the results of composition analysis of the α-olefin low polymer by gas chromatography.

Examples 2 and 3 In order to change the method of contacting ethylene with a chromium-based catalyst,
n-heptane, trispentafluorophenylboron,
An n-heptane solution of triethylaluminum and an n-heptane solution of pyrrole were charged into the autoclave barrel side, and n
-Reaction was carried out in the same manner as in Example 1 except that chromium (III) (2-ethylhexanoate) solutionized with heptane was charged into the catalyst feed tube, and the amount of the boron compound added was changed as shown in Table 1. Was done. The total amount of n-heptane is 50
ml. Table 1 shows the results.

Example 4 In order to change the method of contacting ethylene with a chromium-based catalyst,
n-heptane, trispentafluorophenylboron,
A triethylaluminum n-heptane solution, pyrrole n-heptane solution, chromium (III) 2-ethylhexanoate solutionized with n-heptane are charged into an autoclave in this order, and then ethylene is reduced by introducing ethylene. The reaction was carried out in the same manner as in Example 1, except that the polymerization was started. The total amount of n-heptane was 50 ml. Table 1 shows the results.

Example 5 In order to change the method of contacting ethylene with a chromium-based catalyst,
n-Heptane, n-heptane solution of triethylaluminum, and trispentafluorophenylboron were charged into the body of an autoclave, and chromium (III) (2-ethylhexanoate) and n of pyrrole solutionized with n-heptane
Reaction was carried out in the same manner as in Example 1 except that the heptane solution was charged into the catalyst feed tube. The total amount of n-heptane was 50 ml. Table 2 shows the results.

Examples 6 to 11 Reactions were carried out in the same manner as in Example 4 except that the reaction conditions were changed as shown in Tables 2 and 3. The results are shown in Tables 2 and 3.

Example 12 In the same manner as in Example 4, triethylaluminum and trispentafluorophenylboron (50 mg, 0.100
mmol), chromium (III) (2-ethylhexanoate) and pyrrole were charged into an autoclave. 3.5 kg / cm ^{2 of} hydrogen was introduced, and the autoclave was heated to 100 ° C.
Heated. When ethylene was introduced from the catalyst feed tube at 100 ° C., polymerization of ethylene started. Ethylene is introduced up to a total pressure of 40 kg / cm ^{2 and} then a total pressure of 40 kg
/ Cm ² and a reaction temperature of 100 ° C. Table 3 shows the results.

Example 13 <Production of Chromium Compound-2> Powdery lithium pyrrolide (1.3) prepared separately in a toluene (15 ml) solution of chromium (III) acetylacetonate (2.55 g, 7.3 mmol). (60 g, 21.9 mmol) in toluene (5 ml) was added at room temperature under a nitrogen atmosphere. The reaction mixture was slowly heated to 100 ° C., and stirring was continued for 25 hours while maintaining the temperature. After cooling the reaction mixture to room temperature, the solvent was distilled off under reduced pressure to obtain 4.15 g of a red-brown powder. The results of elemental analysis of this powder were as follows. Cr: 9.1%; C: 57.0%; H: 5.9%;
N: 7.4% A 300 ml autoclave heated and dried in a dryer at 150 ° C. was assembled while hot, and then replaced with vacuum nitrogen. n-
A solution of n-heptane of heptane and triethylaluminum was charged into the autoclave barrel side, and trispentafluorophenylboron (50 mg, 0.100 mmol)
l) The reaction was carried out in the same manner as in Example 1 except that the chromium compound-2 slurried with n-heptane was charged into the catalyst feed tube. Table 4 shows the results.

Example 14 Trispentafluorophenylboron (50 mg, 0.1 mg
100 mmol) instead of tetrakis (pentafluorophenyl) borate dimethylanilinium (80 m
g, 0.100 mmol), an n-heptane solution of n-heptane and triethylaluminum was charged into the autoclave barrel side, and a chromium compound slurried with tetrakis (pentafluorophenyl) borate dimethylanilinium and n-heptane Reaction was carried out in the same manner as in Example 1 except that -2 was charged in the catalyst feed tube. Table 4 shows the results.

Comparative Example 1 A reaction was carried out in the same manner as in Example 1 except that the boron compound was not added and the reaction time was 1 hour. Table 5 shows the results.

Comparative Example 2 A reaction was conducted in the same manner as in Example 13 except that the boron compound was not added and the reaction time was 1 hour. Table 5 shows the results
Shown in

In each of the tables, the solvent type “HP” represents n-heptane, and the Cr compound type “Cr-1” represents chromium (II).
I) 2-ethylhexanoate, "Cr-2" represents the chromium compound synthesized in Example 13. In addition, "B-1" of the boron compound type represents trispentafluorophenylboron, and "B-2" represents tetrakis (pentafluorophenyl) borate dimethylanilinium.

In each table, "contact method A" refers to a method of introducing a chromium compound, a boron compound and an α-olefin into a solution containing an alkyl aluminum compound and pyrrole, and "contact method B" refers to an alkyl aluminum compound. A method of introducing a chromium compound and an α-olefin into a solution containing pyrrole and a boron compound, “contact method C” includes a boron compound, an alkylaluminum compound,
Pyrrole, a method of introducing an α-olefin into a solution charged in the order of the chromium compound, `` contact method D '' is a method of introducing a chromium compound, pyrrole and an α-olefin into a solution containing an alkyl aluminum compound and a boron compound, "Contact method E" represents a method of introducing a chromium compound, a pyrrole, a boron compound, and an α-olefin into a solution containing an alkylaluminum compound, and the unit of the catalyst efficiency is g-α-olefin / 1g-chromium compound, The unit of catalytic activity is g-α-olefin / 1g-chromium.H
r.

[0072]

[Table 1] ──────────────────────────────────── Example 1 2 3 4 Solvent type ( HP (50) HP (50) HP (50) HP (50) Cr compound type Cr-1 Cr-1 Cr-1 Cr-1 Cr compound amount (mg) 10 10 10 10 Cr compound (mmol) 0.021 0.021 0.021 0.021 Pyrrole (mmol) 0.060 0.060 0.060 0.060 Et ₃ Al (mmol) 0.400 0.400 0.400 0.400 Boron compound type B-1 B-1 B-1 B-1 Amount of boron compound (mmol) 0.020 0.020 0.100 0.020 Reaction temperature ( ℃) 100 100 100 100 Ethylene pressure (Kg / cm ² ) 35 35 35 35 Reaction time (Hr) 0.25 0.25 0.25 0.25 Contact method ABBC <Product amount (g)> 14.4 14.4 38.0 13.7 <Composition distribution (wt% )> C ₄ 1.7 1.9 0.2 1.4 C ₆ 79.5 74.5 83.2 80.3 1-hexene content in C ₆ (wt%) 94.6 94.6 94.4 94.9 C ₈ 2.7 3.0 0.5 2.1 C _10-20 13.9 17.9 15.2 14.0 C _22-30 1.4 2.0 0.5 1.3 Wax 0.0 0.0 0.0 0.0 By-product PE 0.5 0.3 0.3 0.7 <catalytic efficiency> 1439 1439 3799 1367 <catalytic activity > 53313 53328 140699 50616

[0073]

[Table 2] ──────────────────────────────────── Example 5 6 7 8 Solvent type ( HP (50) HP (50) HP (50) HP (50) Cr compound type Cr-1 Cr-1 Cr-1 Cr-1 Cr compound amount (mg) 10 10 10 10 Cr compound (mmol) 0.021 0.021 0.021 0.021 Pyrrole (mmol) 0.060 0.060 0.060 0.060 Et ₃ Al (mmol) 0.400 0.400 0.400 0.400 Boron compound type B-1 B-1 B-1 B-1 Amount of boron compound (mmol) 0.020 0.100 0.100 0.060 Reaction temperature ( ° C) 100 60 45 100 Ethylene pressure (Kg / cm ² ) 35 35 35 35 Reaction time (Hr) 0.25 0.25 0.25 0.25 Contact method D DD D <Amount of product (g)> 19.1 23.0 24.7 33.2 <Composition distribution (wt% )> C ₄ 1.2 0.3 0.7 0.3 C ₆ whole 79.1 85.5 81.8 82.8 1-hexene content in C ₆ (wt%) 94.4 95.3 94.8 94.2 C ₈ 1.9 0.7 0.9 0.6 C _10-20 15.7 11.3 14.3 15.2 C _22-30 1.1 0.3 0.4 0.5 Wax 0.0 0.1 0.2 0.1 byproduct PE 0.7 1.8 1.8 0.5 <catalytic efficiency> 1910 2302 2476 3318 <catalytic activity 70729 85272 91720 122885

[0074]

Table 3 ──────────────────────────────────── Example 9 10 11 12 Solvent type ( HP (50) HP (50) HP (50) HP (50) Cr compound type Cr-1 Cr-1 Cr-1 Cr-1 Cr compound amount (mg) 10 10 10 10 Cr compound (mmol) 0.021 0.021 0.021 0.021 Pyrrole (mmol) 0.060 0.060 0.060 0.060 Et ₃ Al (mmol) 0.400 0.400 0.200 0.400 Boron compound type B-1 B-1 B-1 B-1 Boron compound amount (mmol) 0.004 0.004 0.004 0.004 Reaction temperature ( ℃) 100 100 100 100 Ethylene pressure (Kg / cm ² ) 35 70 35 35 (H ₂ 3.5KG)) Reaction time (Hr) 0.25 0.25 0.25 0.25 Contact method D DD D <Product amount (g)> 6.7 15.9 3.9 14.9 <composition distribution _{(wt%)> C 4 2.4} 3.5 3.6 1.9 C 6 total 78.7 78.2 79.4 78.8 1-hexene content in _{C 6 (wt%) 94.5 95.0} 94.3 92.0 C 8 3.5 3.9 3.6 2.2 C 10-20 14.2 13.9 12.2 16.7 C _22-30 1.1 0.5 0.8 0.4 Wax 0.1 0.0 0.1 0.0 By-product PE 0.1 0.1 0.3 0.1 <Catalytic efficiency> 667 1588 386 148 8 <Catalytic activity> 24711 58797 14303 55111

[0075]

[Table 4]

[0076]

[Table 5]

[0077]

According to the method of the present invention, α-olefin,
In particular, a low-polymerization of ethylene can selectively produce a product mainly composed of a trimer, particularly a hexene having a high purity of 1-hexene in a high yield, and suppress the production of a high-molecular-weight polymer. Can provide significant industrial benefits.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-239920 (JP, A) JP-A-3-128904 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 4/69

Claims (6)

(57) [Claims] 1. A method for producing an α-olefin low polymer by low polymerization of an α-olefin in the presence of a chromium catalyst, wherein the chromium catalyst comprises at least a chromium compound, an amine or a metal amide, and an alkylaluminum compound. And a catalyst system comprising a combination of compounds represented by the following general formulas (1) and (2). Embedded image Embedded image (Wherein, M ¹ and M ² are elements selected from B, Al, and In , and R ^{1 to} R ⁷ are a hydrogen atom, a dialkylamino group, and a carbon number.
1 to 20 alkoxy groups, 6 to 20 carbon atoms arylo
Xy group, alkyl group having 1 to 20 carbon atoms, 6 to 20 carbon atoms
Aryl group, alkylaryl group, arylalkyl
Group, halogen-substituted hydrocarbon group having 1 to 20 carbon atoms, carbon number
1-20 acyloxy groups, alkoxy having 1-20 carbon atoms
Cyaryl group, halogen-substituted alkoxy having 1 to 20 carbon atoms
From cyaryl groups, organic metalloid groups or halogen atoms
R ^{1 to} R ⁷ are two or more of each other
[L] ⁺ , which may combine with each other to form a ring, is selected from groups 1, 7, 8, 10, 11, and 13 to 16 of the periodic table.
Shows a cation containing an element selected from the group . ) 2. The compound represented by the general formula (1) wherein L is M
^{3, M 4 R 8 R 9} , E 1 R 10 R 11 R 12 or ^{E 2 R 13 R 14 R 15} R
Are those represented by ^16, 1 Group M ³ represents the periodic table, 11
M ⁴ is an element selected from Group 13 and Group 13 ;
An element selected from Group 10 ; E ¹ represents a carbon atom, an oxygen atom or a sulfur atom, E ² represents a nitrogen atom or a phosphorus atom, and R ⁸ and R ⁹ are a cyclopentadienyl group, a substituted cyclopentadienyl group, an indenyl Or a substituent selected from a fluorenyl group, which may combine with each other to form a ring, and R ^{10 to} R ^{16 each} represent a hydrogen atom, a halogen atom,
2. The method for producing an α-olefin low polymer according to claim 1, which is selected from 20 alkyl groups, 6 to 20 carbon aryl groups, alkylaryl groups, arylalkyl groups, and organic metalloid groups. 3. The α-olefin or chromium compound according to claim 1, wherein an α-olefin or a chromium compound is introduced into a solution containing an amine, an alkylaluminum compound, and a compound represented by the general formula (1) or (2). -A method for producing an olefin low polymer. 4. A solution containing an alkylaluminum compound and a compound represented by the general formula (1) or (2),
The method for producing an α-olefin low polymer according to claim 1 or 2, wherein an olefin, a chromium compound, and an amine or a metal amide are introduced. 5. A chromium compound, an amine or a metal amide,
The method for producing an α-olefin low polymer according to claim 1 or 2, wherein the α-olefin and the alkylaluminum compound are introduced into a solution containing the compound represented by the general formula (1) or (2). 6. The α-olefin is ethylene;
The method for producing an α-olefin low polymer according to any one of claims 1 to 5, wherein the olefin low polymer is mainly 1-hexene.