JP2016155065A - Catalyst composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst for producing a low polymer of an α-olefin such as a novel ethylene, in which the catalyst has a low rate of polymer formation and a high catalytic activity.SOLUTION: There is provided a catalyst composition comprising a chromium compound, a predetermined bidentate phosphite compound and an organoaluminum compound, in which a complex compound obtained from the chromium compound and the bidentate phosphite compound is used as a main catalyst and the organoaluminum compound is used as a co-catalyst. The main catalyst complex compound has chromium as a central metal and is formed by coordinating at least one molecule of the bidentate phosphite compound serving as a ligand to the one central metal.SELECTED DRAWING: None

Description

  The present invention relates to a catalyst composition. Specifically, the present invention relates to a catalyst composition that can low-polymerize α-olefin, particularly ethylene, and selectively obtain oligomers such as trimers and tetramers in high yield.

  Conventionally, a catalyst for producing an oligomer by low polymerization of an α-olefin such as ethylene is known. For example, a catalyst using a monodentate ligand in which the coordination atom is a nitrogen atom (Patent Documents 1 to 3), a bidentate ligand in which the coordination atom is a nitrogen atom or a phosphorus atom, Is known to be a catalyst crosslinked with a nitrogen atom or a hydrocarbyl group (Patent Document 4).

JP-A-2005-105286 Special table 2008-533330 gazette JP 2000-313714 A JP 2006-511625 A

  By the way, the catalyst for the low polymerization reaction of ethylene is considered to have various catalysts other than the catalysts described in the above-mentioned documents. Depending on the catalyst, polymerization of α-olefin becomes dominant, In some cases, the production rate of the oligomer is lowered, or the polymer production rate of the α-olefin is low, but the catalytic activity itself is low.

  Therefore, an object of the present invention is to obtain a novel α-olefin low polymerization catalyst such as ethylene having a low polymer production rate and high catalytic activity.

The present inventors have solved the above-mentioned problems by finding a catalyst composition having the following [1] to [4].
That is, the present invention relates to the following. [1] A catalyst composition comprising a chromium compound, a bidentate phosphite compound having a structure of any one of the following general formulas (1) to (3), and an organoaluminum compound.

(In the above formulas (1) to (3), R ^{11 to} R ¹⁶ each independently represent an alkyl group or an aryl group, and may further have a substituent, and Z ¹ to Z ³ and ^a 1 to a ³ are each independently, may have a substituent group alkylene group, an alkylene - arylene group, an arylene group, or a ^{-Ar 1 - (Q 1) n} -Ar 2 - of A diarylene group optionally having a divalent linking group in the middle thereof (however, Ar ¹ and Ar ² are each independently an arylene group having 6 to 18 carbon atoms which may have a substituent) Represents.)

[2] The catalyst composition according to [1], wherein in the general formulas (1) to (3), the structure of A ^{1 to} A ³ is represented by the following general formula (4).

(In Formula (4), R ^{21 to} R ²⁸ are each independently a hydrogen atom, a halogen atom, a hydroxy group, an aryl group, or an aryloxy group, a chain or cyclic alkyl group, an alkoxy group, an amino group, Represents an acyl group, an acyloxy group, a carboxy group, or an ester group, which may further have a substituent, and any two substituents may form a bond to form a cyclic structure; good.)

[3] The catalyst composition according to [2], wherein in the general formula (4), at least R ²¹ and R ²⁸ are a linear or cyclic alkyl group having 1 to 8 carbon atoms.
[4] A method for oligomerizing ethylene using the catalyst composition according to any one of [1] to [3].

  According to the method of the present invention, it is possible to selectively polymerize α-olefins, particularly ethylene, to selectively obtain trimers and tetramer oligomers in high yield, and to produce high molecular weight polymers. It can be suppressed and provides great industrial benefits.

  Embodiments of the catalyst composition of the present invention will be described in detail below, but the description described below is an example (representative example) of an embodiment of the present invention, and the present invention is not limited to these contents.

The catalyst composition according to the present invention is a composition containing a chromium compound, a bidentate phosphite compound having a predetermined structure, and an organoaluminum compound.
The complex compound obtained from the chromium compound and the bidentate phosphite compound is used as a main catalyst, and the organoaluminum compound is used as a promoter. The complex compound as the main catalyst is a complex compound formed by coordinating the bidentate phosphite compound as a ligand to one atom of the central metal with chromium of the chromium compound as a central metal.

[Cocatalyst]
As described above, an organoaluminum compound is used as a promoter. As this organoaluminum compound, in particular, the condensed organoaluminum compound, which is a condensation product obtained by partial hydrolysis of the organoaluminum compound, efficiently activates the central metal of the main catalyst in the oligomerization of α-olefin. So it is more preferable. Examples of such condensed organoaluminum compounds include methylaluminoxane obtained by partially hydrolyzing trimethylaluminum and the like.

[Main catalyst]
[Main catalyst-Chromium compound]
Chromium is used as the central metal of the complex compound constituting the main catalyst. This chromium is trivalent chromium and forms a complex with six coordination numbers. Examples of such a chromium compound include chromium (IV) -tert-butoxide, chromium (III) acetylacetonate, chromium (III) trifluoroacetylacetonate, chromium (III) hexafluoroacetylacetonate, chromium (III) ( 2,2,6,6-tetramethyl-3,5-heptanedionate), chromium (III) acetate, chromium (III) -2-ethylhexanoate, chromium (III) benzoate, chromium (III) naphthenate, Chromium (III) heptanoate, Cr (CH ₃ COCHCOOCH ₃ ) ₃ , Cr (PhCOCHCOPh) ₃ (where Ph represents a phenyl group), chromium (II) acetate, first chromium chloride, second chromium chloride, Chromium bromide, chromic bromide, iodine iodide Chromium, chromic iodide, first chromium fluoride, chromic like fluoride and the like.

[Main catalyst-bidentate phosphite compound]
(Basic skeleton)
A bidentate phosphite compound, which is a ligand of a complex compound constituting the main catalyst, has two phosphite groups as shown in the following chemical formula (L), and connects two phosphite groups. A, a compound having a structure of terminal portions Z ₀ ^{1 to} Z ₀ ⁴ linked to each phosphite group.
(Z ₀ ¹ -O) (Z ₀ ² -O) -P-O-A-O-P- (O-Z ₀ ³ ) (O-Z ₀ ⁴ ) (L)
Below, this compound is explained in full detail.
Examples of the chemical formula (L) in the present invention include the following chemical formulas (1) to (3).

^(R 11 ~R ¹⁶⁾
In the general formulas (1) to (3), R ^{11 to} R ¹⁶ each independently represents a chain or cyclic alkyl group or an aryl group. Examples of alkyl groups include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, sec-butyl, t-butyl, hexyl, octyl, decyl Group, cyclopentyl group, cyclohexyl group, cycloheptyl group and the like. Examples of aryl groups include phenyl, tolyl, xylyl, di-t-butylphenyl, naphthyl, di-t-butylnaphthyl, pyridyl, pyrrolyl, pyrazolyl, imidazolyl, quinolyl, Examples thereof include an isoquinolyl group, an indolyl group, a furanyl group, a thiophenyl group, an oxazolyl group, and a thiazolyl group.

  Note that the above-described alkyl group and aryl group may further have a substituent. The substituent is not particularly limited as long as it does not adversely affect the reaction system. Specifically, a hydroxy group, a halogen atom, a cyano group, a nitro group, a formyl group, an alkyl group, an alkoxy group, An aryl group, aryloxy group, amino group, amide group, perfluoroalkyl group, trialkylsilyl group, ester group and the like are preferable.

The number of carbon atoms of the above ^R 11 ^{to R 16} is usually 1 to 40, preferably 1 to 30, more preferably 1 to 20. When the above-described alkyl group or aryl group further has a substituent, the total number of carbon atoms including the substituent is set in the above range.

Among the above exemplified groups, considering the stability of the bidentate phosphite compound, R ^{11 to} R ¹⁶ are preferably unsubstituted or substituted aryl groups. Specific examples of the unsubstituted or substituted aryl group include phenyl group, 2-methylphenyl group, 3-methylphenyl group, 4-methylphenyl group, 2,3-dimethylphenyl group, 2,4-dimethylphenyl group, 2,5-dimethylphenyl group, 2,6-dimethylphenyl group, 2-ethylphenyl group, 2-isopropylphenyl group, 2-t-butylphenyl group, 2,4-di-t-butylphenyl group, 2- Chlorophenyl group, 3-chlorophenyl group, 4-chlorophenyl group, 2,3-dichlorophenyl group, 2,4-dichlorophenyl group, 2,5-dichlorophenyl group, 3,4-dichlorophenyl group, 3,5-dichlorophenyl group, 4- Trifluoromethylphenyl group, 2-methoxyphenyl group, 3-methoxyphenyl group, 4-methoxyphenyl group, 3,5-di Toxiphenyl group, 4-cyanophenyl group, 4-nitrophenyl group, pentafluorophenyl group, 1-naphthyl group, 2-naphthyl group, 2-methyl-1-naphthyl group, 3-t-butyl-2-naphthyl group 3-methyloxycarbonyl-2-naphthyl group, 3,6-di-t-butyl-2-naphthyl group, 5,6,7,8-tetrahydronaphthalen-2-yl group, 5,6,7,8 -Tetrahydronaphthalen-1-yl group etc. are mentioned.

^{(Z 1 ~Z 3, A 1} ~A 3)
^Z 1 to Z ³ and ^A 1 to A ³ described above, each independently, represent a divalent organic group. The type is not particularly limited as long as it does not adversely affect the reaction system, but an unsubstituted or substituted alkylene group, arylene group, alkylene-arylene group, or diarylene group is preferable.

Z ¹ to Z ³ and the number of carbon atoms of each of ^A 1 to A ³ is usually 1 to 60. Among them, in the case of an unsubstituted or substituted alkylene group, an unsubstituted or substituted arylene group, or an unsubstituted or substituted alkylene-arylene group, the carbon number is usually 40 or less, preferably 30 or less, more preferably 20 or less. It is. On the other hand, in the case of an unsubstituted or substituted diarylene group, the carbon number is usually 60 or less, preferably 50 or less, and more preferably 40 or less.

  The alkylene group may be a chain or a ring. Preferred examples of the substituent that the alkylene group may have include a hydroxy group, a halogen atom, a cyano group, a nitro group, a formyl group, an alkyl group, an alkoxy group, an aryl group, an aryloxy group, an amino group, an amide group, Examples include a perfluoroalkyl group, a trialkylsilyl group, and an ester group. Specific examples of the unsubstituted or substituted alkylene group include an ethylene group, a tetramethylethylene group, a 1,3-propylene group, a 2,2-dimethyl-1,3-propylene group, and a 1,4-butylene group. It is done.

  Preferable examples of the substituent that the arylene group may have include the same groups as the preferable examples of the substituent that the alkylene group may have. Specific examples of the unsubstituted or substituted arylene group include 1,2-phenylene group, 1,3-phenylene group, 3,5-di-t-butyl-1,2-phenylene group, and 2,3-naphthylene group. 1,4-di-t-butyl-2,3-naphthylene group, 1,8-naphthylene group and the like.

(Z ^{1 to} Z ³ , A ^{1 to} A ³ : unsubstituted or substituted alkylene-arylene group)
Preferable examples of the substituent that the alkylene-arylene group may have include the same groups as the preferable examples of the substituent that the alkylene group may have. Specific examples of the unsubstituted or substituted alkylene-arylene group include substituents having structures represented by the following formulas (D-1) to (D-12).

^{(Z 1 ~Z 3, A 1} ~A 3: Jiariren group)
The diarylene group is a group in which two arylene groups are linked directly or via a divalent organic group. Specifically, -Ar ^1- (Q ¹ ) _n -Ar ^2- A group having the structure represented. Here, Ar ¹ and Ar ² each independently represent an arylene group which may have a substituent. The arylene group usually has 6 to 30 carbon atoms. Especially, the carbon number is 30 or less normally, Preferably it is 25 or less, More preferably, it is 20 or less. On the other hand, the lower limit of the carbon number is usually 6 or more, preferably 8 or more, more preferably 10 or more.

Q ¹ represents a divalent organic group. Specific examples thereof include a group represented by —O—, —S—, —CO—, or —CR ¹⁷ R ¹⁸ —. Here, R ¹⁷ and R ¹⁸ each independently represent a hydrogen atom, an alkyl group which may have a substituent, or an aryl group which may have a substituent. n represents 0 or 1. Preferable specific examples of the substituent that each of the arylene group of Ar ¹ and Ar ² and the alkyl group and aryl group of R ¹⁷ and R ¹⁸ may have may include the above-described alkylene group. Examples thereof include the same groups as the preferable examples of good substituents.

Trend in the A ¹ to A ³ described above, among the above Jiariren group, the use of Jiariren group having a structure represented by the following general formula (4), to suppress the polymerization of α- olefins, promote oligomerization Is more preferable.

In the general formula (4), R ^{21 to} R ²⁸ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, an aryl group, an aryloxy group, an alkyl group, an alkoxy group, an amino group, an acyl group, an acyloxy group, Represents a carboxy group or an ester group. Of these, an alkyl group, an alkoxy group, an amino group, an acyl group, an acyloxy group, a carboxy group, or an ester group has a chain or cyclic structure. These groups may further have a substituent, and any two substituents may form a bond to form a cyclic structure. Preferable specific examples of the substituent include the same groups as the preferable examples of the substituent which the alkylene group may have.

When R ^{21 to} R ²⁸ of the general formula (4), at least R ²¹ and R ²⁸ , use a linear or cyclic alkyl group having 1 to 8 carbon atoms, the stability of the bidentate phosphite compound is improved. Since it increases, it is more preferable. The lower limit of the carbon number is more preferably 3, and the upper limit thereof is more preferably 5.

  Specific examples of the diarylene group including the diarylene group represented by the general formula (4) include groups having a structure represented by the following formulas (A-1) to (A-18).

(Specific examples of bidentate phosphite compounds)
As described above, as the bidentate phosphite compounds represented by the above general formulas (1) to (3), bidentate phosphite compounds having various structures can be mentioned depending on the combination of constituent substituents. . Among them, preferred specific examples include bidentate phosphites having structures represented by the following formulas (L-6) to (L-69).

In order to improve the stability of the phosphite compound, R ^{11 to} R ¹⁶ are each independently an unsubstituted or substituted aryl group, and Z ^{1 to} Z ³ and A ^{1 to} A ³ are each independently unsubstituted or substituted. A substituted diarylene group is preferred, and specific examples of such a bidentate phosphite are the above formulas (L-18) to (L-20), (L-24) to (L-30). ), (L-39), (L-45), (L-46), (L-52) to (L-62), and (L-66) to (L-69). . Among them, more preferred are bidentate phosphite compounds using diarylene groups represented by the above general formula (4) as A ^{1 to} A ³ , and specific examples thereof include the above formulas (L-24) to (L— 30), (L-45), (L-46), (L-52) to (L-62). Furthermore, among these, the most preferred structure is a bidentate phosphite compound having a structure in which the terminal groups represented by the general formula (1) do not have a bond to each other. And compounds of L-24) to (L-30), (L-57), and (L-59) to (L-62).

[Combination ratio]
The mixing ratio of the bidentate phosphite compound to 1 equivalent of the chromium compound is preferably 0.1 equivalent or more, and preferably 0.5 equivalent or more. If the amount is less than 0.1 equivalent, the activity of the oligomerization reaction may hardly be exhibited, or only polymer formation may proceed. On the other hand, the upper limit of the blending ratio is preferably 5 equivalents or less, and preferably 2 equivalents or less. If it is more than 2 equivalents, the catalytic activity may be reduced.

  Moreover, the compounding ratio of the organoaluminum compound (co-catalyst) with respect to the number of moles of chromium of the complex compound (main catalyst) composed of the chromium compound and the bidentate phosphite compound is as follows: 10 mol or more is good and 50 mol or more is preferable. If it is less than 50 mol, the catalytic activity may be reduced. On the other hand, the upper limit of the mixing ratio is preferably 1000 mol or less, and preferably 500 mol or less. When the amount is more than 500 moles, the amount of the cocatalyst used is excessively high, which is not efficient, and the cost of the cocatalyst may become very high.

[Method for oligomerizing α-olefin]
Using the above catalyst composition, α-olefin such as ethylene is subjected to a polymerization reaction under conditions such as temperature and pressure during general polymerization, thereby α-olefin trimer, tetramer, etc. Can be obtained in high yield.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention further in detail, this invention is not limited to a following example, unless the summary is exceeded.

<Raw materials>
Bidentate phosphites: with reference to JP-A-62-116587, JP-A-08-259578, JP-A-09-087292, JP-A-10-045776, JP-A-11-130720, etc. A small amount was synthesized for the examples. In addition, for bidentate phosphites not described in these publications, using the methods described in these publications, the corresponding crosslinking part raw materials (diols and biphenols) and terminal raw materials (alcohols and phenols) ) Was synthesized.

・ Cr (acac) ₃ toluene solution: Chromium (III) acetylacetonate manufactured by Wako Pure Chemical Industries, Ltd. is dissolved in toluene (for organic synthesis, ultra-dehydrated product) manufactured by Wako Pure Chemical Industries, Ltd. To prepare a Cr (acac) ₃ toluene solution.
N-Undecane: Wako Pure Chemical Industries, Ltd .: Used as an internal standard substance for gas chromatography analysis.
Methylaluminoxane: A toluene solution of 10 wt% methylaluminoxane (= aluene solution of methylaluminoxane having a concentration of 1500 mmol / l as an aluminum atom) manufactured by Aldrich Co., Ltd. was used.

<Examples 1-15>
0.018 mmol of bidentate phosphite described in Table 1 or 2 was put into a glass Schlenk tube, and after nitrogen substitution, 1.8 ml of a toluene solution containing 8.4 mmol / l of Cr (acac) ₃ was added ( About 0.15 mmol as Cr) was added and stirred with a magnetic stir bar to dissolve the bidentate phosphite at room temperature. Subsequently, 10.2 ml of toluene and 1.0 ml of n-undecane (internal standard substance for gas chromatography analysis) were added, and 2.0 ml of a toluene solution of methylaluminoxane having a concentration of 1500 mmol / l as aluminum atoms (Al As a catalyst solution was prepared.
The above catalyst solution was completely introduced into a magnetic induction stirring type stainless steel autoclave having a dry volume of 50 ml under a nitrogen gas atmosphere, and after sealing, the internal solution of the autoclave was heated to 40 ° C. while stirring, Ethylene was fed into the solution so that the internal pressure (gauge pressure) was 3.0 MPa, and reacted for about 15 minutes while controlling the temperature at 40 ° C. as it was. During the reaction, ethylene was continuously supplied so that the ethylene pressure in the system was maintained at 3.0 MPa.
After completion of the reaction, the reaction vessel was cooled with ice water and cooled to 10 ° C., purged with ethylene gas, the autoclave was opened, and the entire reaction solution was collected in a glass vessel. 1 ml of ethanol was added to the collected reaction liquid and stirred, and 5 ml of 2 mol / l hydrochloric acid was further added and stirred, and then allowed to stand to collect the upper toluene phase in another glass container. Subsequently, the toluene phase was washed with 15 ml of water, and a reaction product (trimer or tetramer oligomer) was quantified by analyzing a part of the toluene phase by gas chromatography. . Then, the production rate of oligomers (the amount of oligomer production (g) per 1 g of chromium content and per hour) was calculated. In addition, when the polymer was produced | generated when the autoclave was open | released, after collect | recovering separately and making it dry under reduced pressure, the weight was measured and the production rate was calculated. The results are shown in Table 3.

  The selectivity of 1-hexene among the C6 (hexene) produced was in the range of 97 to 98% in Examples 1 to 15. Moreover, the selectivity of 1-octene among C8 (oxene) to produce | generate was also in the range of 97 to 98% in Examples 1-15.

[Discussion]
Among the bidentate phosphite compounds exemplified above, the phosphite compounds of the above formulas (L-6) to (L-69) are preferable. Furthermore, in order to improve the stability of the phosphite compound, R ^{11 to} R ¹⁶ are each independently an unsubstituted or substituted aryl group, and Z ^{1 to} Z ³ and A ^{1 to} A ³ are each independently A substituted or substituted diarylene group is preferable, and specific examples of such a bidentate phosphite are the above formulas (L-18) to (L-20) and (L-24) to (L-24). -30), (L-39), (L-45), (L-46), (L-52) to (L-62), (L-66) to (L-69). Can do. Among them, more preferred are bidentate phosphite compounds using diarylene groups represented by the above general formula (4) as A ^{1 to} A ³ , and specific examples thereof include the above formulas (L-24) to (L— 30), (L-45), (L-46), (L-52) to (L-62). Furthermore, among these, the most preferred structure is a bidentate phosphite compound having a structure in which the terminal groups represented by the general formula (1) do not have a bond to each other. And compounds of L-24) to (L-30), (L-57), and (L-59) to (L-62).

Claims (4)

A catalyst composition comprising a chromium compound, a bidentate phosphite compound having a structure of any one of the following general formulas (1) to (3), and an organoaluminum compound.

(In the formulas (1) to (3), R ^{11 to} R ¹⁶ each independently represents a chain or cyclic alkyl group or an aryl group, and may further have a substituent, Z ^{1 to} Z ³ and A ^{1 to} A ³ are each independently an optionally substituted alkylene group, alkylene-arylene group, arylene group, or -Ar ^1- (Q ¹ ) n-Ar ^2. A diarylene group optionally having a divalent linking group in the middle thereof (wherein Ar ¹ and Ar ² are each independently an optionally substituted substituent having 6 to 18 carbon atoms) Represents an arylene group.) In formula (1) to (3), the structure of A ¹ to A ³ is A catalyst composition according to claim 1, characterized by being represented by the following general formula (4).

(In Formula (4), R ^{21 to} R ²⁸ are each independently a hydrogen atom, a halogen atom, a hydroxy group, an aryl group, or an aryloxy group, a chain or cyclic alkyl group, an alkoxy group, an amino group, Represents an acyl group, an acyloxy group, a carboxy group, or an ester group, which may further have a substituent, and any two substituents may form a bond to form a cyclic structure; good.) In the general formula (4), at least R ²¹ and catalyst composition of claim 2 in which R ²⁸ is characterized in that it is a chain or cyclic alkyl group having 1 to 8 carbon atoms.   The ethylene oligomerization method using the catalyst composition of any one of Claims 1-3.