WO1994015940A1

WO1994015940A1 - Process for producing olefin oligomer

Info

Publication number: WO1994015940A1
Application number: PCT/JP1994/000033
Authority: WO
Inventors: Haruhito Satou; Harumi Nakashima
Original assignee: Idemitsu Kosan Co., Ltd.
Priority date: 1993-01-13
Filing date: 1994-01-13
Publication date: 1994-07-21

Abstract

A process for producing a reduced chromium complex by reducing at least one compound selected from among chromium (III) and chromium (IV) compounds each having an oxygen anion as the ligand with a reducing agent in the presence of an electron donor into a chromium (II) compound; a process for producing a reduced chromium complex catalyst by mixing an electron donor, at least one compound selected from among chromium (III) to chromium (VI) compounds each having an oxygen anion as the ligand, a reducing agent, and an aluminumoxy compound; and a process for producing an olefin oligomer by the reaction of an olefin in the presence of the obtained reduced chromium complex catalyst. This process enables hexene-1 and octene-1 useful as comonomers of linear low-density polyethylene (L-LDPE) to be produced selectively and efficiently.

Description

Specification

Method for producing oligomer

Technical field

The present invention relates to a method for producing an oligomer, a method for producing a reduced chromium complex catalyst and a method for producing a reduced chromium complex used in the production method, and more particularly to a comonomer of linear low density polyethylene (L-LDPE). The present invention relates to a method for producing a olefin oligomer capable of selectively and efficiently producing hexene-11 and octene-11, which is useful as a catalyst, a method for producing a reduced chromium complex catalyst used in the production method, and a method for producing a reduced chromium complex. is there.

Background art

In recent years, one-year-old olefins having 4 to 12 carbon atoms, especially hexene-1 and octene-1, have been known to be useful compounds as comonomers for linear low-density polyethylene (L-LDPE). It is also known that these oligomers can be produced by oligomerization of ethylene or the like.

Ethylene oligomerization technologies include, as industrialized products, oligomer production technology according to Schultz's Flory rule and oligomer production technology represented by Poisson distribution. In the former technique, the molecular weight distribution of the oligomer is indicated by α value, but when the α value is 0.5, the amount of butene-1 generated is large, and when the α value is 0.7, the number of carbon atoms is 10 or more. The amount of high-molecular-weight α-refin produced is too high to selectively produce a comonomer for L-LDPE.

On the other hand, the latter technique can produce α-olefins having 6 or 8 carbon atoms relatively selectively. However, a detailed explanation of the Etoli's oligomer production technology, which employs this technology, the so-called improved Ethil method, was made in detail. After the analysis, the generated C4 olefin is recycled, the reaction process is divided into two stages, an alkyl process and a substitution process, and a complex process is required, such as using a catalyst for stoichiometry. Has become. In other words, the technology for the oligomerization of ethylene mentioned here is a technology that has been known for a long time.However, oligomer production cannot be achieved unless a solid acid catalyst is used in combination and the activity cannot be increased. The technology has many challenges.

In the oligomer production technology as described above, conventionally, an ethylene oligomer trimerization catalyst using chromium element has been known as an oligomer oligomerization catalyst. However, for example, in the case of the chromium carbo'xylate-based catalyst disclosed in Japanese Patent Publication No. 4-666457, the formation of oligomer is only hexene-11 and the catalytic activity is low. Was. In addition, in the case of the chrome pyrrolide catalyst disclosed in Japanese Patent Application Laid-Open No. 3-115406, although the amount of produced polymer can be reduced to several percent or less, there is a problem that the reaction rate is slow. . In order to increase the reaction rate, it is necessary to use a solid acid.In this case, when a solid acid insoluble in a hydrocarbon solvent is used for the reaction, a filtration step is used as post-treatment of the reaction. In addition, it was difficult to build a process such as preparation of solid acid and addition of powder.

Disclosure of the invention

Under such circumstances, hexene-1 and octene-11, which are particularly useful as comonomers of linear low-density polyethylene (L-LDPE), are converted to olefins, especially ethylene Method for producing industrially advantageous oligomers of oligomers which can be selectively and efficiently produced by means of gomarization, reduced chromium complex catalyst used in the production method and reduction thereof Because in has been made for the purpose of providing a method for producing a chromium complex Q ₀

The present invention provides a complex obtained by reducing at least one of trivalent to hexavalent chromium compounds having an oxygen anion as a ligand in the coexistence of an electron donor with a reducing agent to reduce the valence of chromium to divalent. A method for producing a reduced chromium complex for obtaining a compound, characterized in that at least one selected from a trivalent to hexavalent chromium compound having an oxygen anion as a ligand is mixed with a reducing agent and an aluminum oxy compound. And a method for producing an olefin oligomer characterized by reacting an olefin in the presence of a reduced chromium complex catalyst obtained by using the above-described production method. Is what you do.

In the method of the present invention, the trivalent or hexavalent chromium compound having an oxygen anion as a ligand and preferably a trivalent or tetravalent chromium compound used for the production of the reduced chromium complex is not particularly limited. For example, carboxylate such as chromium (3) tris (2-ethylhexanoate), chromium (3) tris (cyclohexyl carboxylate), trisacetyl acetate chromium, tris ( 2,2,6,6—Tetramethyl-3,5—Hebutanedionato) Chelate salts of diketones such as chromium, alcohols such as chromium (4) tetraethoxide and chromium (4) tetra-t-butoxide And the like. One of these chromium compounds may be used, or two or more of them may be used in combination.

In producing the reduced chromium complex of the present invention, an electron donor is used. Such an electron donor may be any substance capable of donating an electron to the center of chromium, for example, cyclic ethers such as tetrahydrofuran, pyran, and dioxane, dimethoxetane, diethylene glycol, and the like. Chain ethers such as methyl dimethyl ether and triethylene glycol dimethyl ether, cyclic vinyl ethers such as 2,3-dihydrofuran, 3,4-dihydro-2H-pyran, methyl vinyl ether, Chain vinyl ethers such as ethylbutyl ether, and cyclic aryl ethers such as 2,5-dihydrofuran, 5, 6-dihydro-1 2H-pyran, methylaryl ether, and ethylaryl ether Aryl ethers, aliphatic amines such as triethylamine and triethylenediamine, aromatic amines such as pyridine and picolin, 2-oxazoline, 6H-1, Heterocyclic compounds such as 2,4-oxazineazine and the like can be mentioned. Of these, tetrahydrofuran, dimethoxetane, 2,3-dihydrofuran, 3,4-dihydro2H-pyran and the like are preferably used. One of these electron donors may be used, or two or more thereof may be used in combination.

The reducing agent used in the present invention may be a substance capable of reducing a trivalent or hexavalent chromium compound having the oxygen anion as a ligand, and is preferably, for example, trimethyl. Organic aluminum such as aluminum, triethylaluminum, triisobutylaluminum, organic zinc such as dimethylzinc, getylzinc, dibutylzinc, lithium aluminum hydride, sodium polo hydride, getylaluminum hydride Such as hydride, dibutylaluminum hydride, sodium hydride, lithium hydride, and other metals such as lithium, sodium, potassium, magnesium, aluminum, and other trivalent or hexavalent metals. Has the effect of reducing trivalent chromium compounds, Inorganic or organic compounds are used. Particularly preferred are trimethyl aluminum and triethyl aluminum. Organic aluminum such as aluminum and triisobutylaluminum is used.

The method for producing a reduced chromium complex according to the present invention is characterized in that the method comprises the steps of: Another object of the present invention is to provide a highly efficient divalent chromium complex.

The amount of each component in the method for producing the reduced chromium complex is not particularly limited, but the electron donor is preferably at least 20 in molar ratio, preferably 20 to 100, based on the chromium compound. 00, more preferably 30 to 500. If this electron donor is used in a molar ratio of 10 or less, the obtained reduced chromium complex is not preferable because it tends to aggregate.

The reducing agent is used in a molar ratio of 1 to 1000, preferably 1 to 2000, with respect to the chromium compound. Here, the amount of the reducing agent used is an amount sufficient to reduce the trivalent or hexavalent chromium compound of the raw material to divalent, and is appropriately determined depending on the type of the reducing agent. Since this reduction step is performed in the coexistence of an electron donor, the reduced chromium complex is prevented from agglomerating and can be obtained with excellent uniformity. In this case, the uniformity can be further improved by adopting the multi-stage reduction method.

Next, in the production of the reduced chromium complex catalyst of the present invention, an aluminum oxy compound is used as a promoter together with the above-mentioned chromium compound, electron donor and reducing agent. As the aluminumoxy compound, those having 1 to 3 oxygen atoms bonded to an aluminum atom are preferably used. For example, trialkyl aluminum such as trimethyl aluminum, triethyl aluminum, and triisobutyl aluminum are used. In hydrolyzing aluminum with water, the amount of water to be added is less than equimolar to the aluminum compound, preferably 0.2 to 0.95, more preferably 0.3 to 0.9 in molar ratio. 0.8 Aluminoxane obtained by hydrolyzing a low-hydrolyzed aluminoxane, trimethylaluminum, triethylaluminum, triisobutylaluminum and other trialkylaluminum with 0.8 moles of water. And the like. That is, as the aluminumoxy compound, an aluminumoxy compound reacted at a ratio of aqueous alkylamine = 0.2 to 1.1 (molar ratio) is preferable. These aluminum oxy compounds may be used alone or in combination of two or more.

The amount of each component in the method for producing the reduced chromium complex catalyst according to the present invention is not particularly limited, but the amounts of the electron donor, the reducing agent and the chromium compound are determined according to the production of the reduced chromium complex. It is not substantially different from the method described. That is, the electron donor is at least 20 in molar ratio, preferably 20 to 100,000, more preferably 30 to 500, and the reducing agent is chromium with respect to the chromium compound. The compound is used in a molar ratio of 1 to 100, preferably 1 to 2000 with respect to the compound. The aluminoxy compound used as a cocatalyst is used in a molar ratio of 1 to 100, preferably 5 to 500, in terms of a molar ratio of the chromium compound to the aluminum.

The catalyst can be produced by various methods, and specifically, the following four methods are mentioned.

(1) An organic aluminum compound hydrolyzed with water in a mixed solution of a trivalent or hexavalent chromium compound having an oxygen anion as a ligand and an electron donor: low hydrolyzed aluminoxane (water Aluminum mole ratio: 0.8 or less, unreacted organic aluminum compound remains) The chromium valence is divalently reduced to obtain a reduced chromium complex catalyst.

(2) An organic aluminum compound hydrolyzed with water in a mixed solution of a trivalent or hexavalent chromium compound having an oxygen anion as a ligand and an electron donor: aluminoxane (mol of aluminum hydroxide) Ratio: 0.8 to 1.1, with few unreacted organoaluminum compounds) and an organoaluminum compound having a reducing power is further added to obtain a reduced chromium complex catalyst in which the chromium valence is divalently reduced. .

(3) An organic aluminum compound having a reducing power is added in advance to a mixed solution of a trivalent or hexavalent chromium compound having an oxygen anion as a ligand and an electron donor to make the chromium valence divalent. As a reduced reduced chromium complex, an aluminum oxide compound: aluminoxane (molar aluminum molar ratio: 0.8 to 1.1, with few unreacted organic aluminum compounds) is added to obtain a reduced chromium complex catalyst .

(4) An organic aluminum compound having a reducing power was previously added to a mixed solution of a trivalent or hexavalent chromium compound having an oxygen anion as a ligand and an electron donor to reduce the valence of chromium to divalent. Then, an organic aluminum compound hydrolyzed with water: a low-hydrolyzed aluminoxane (molar ratio of water / Z aluminum: 0.8 or less and an unreacted organic aluminum compound remaining) is added, and a chromium complex catalyst is added. Get.

Among these production methods, the method using the low hydrolyzed aluminoxane (1) or (4) is preferred.

When vinyl ethers are used as the electron donor, the reduction proceeds relatively easily.When low hydrolyzed aluminoxane is used as the aluminum dimethyl compound, the reduction depends on the remaining organic aluminum compound. Since sufficient reduction of trivalent or hexavalent chromium compounds occurs, it may not be necessary to add a new reducing agent. Also, in the production of this reduced chromium complex catalyst, the electron donor has an important role in the reduction of the chromium compound. It can be adjusted to the optimal amount of electron donor.

Examples of the olefin used in the method for producing an olefin oligomer of the present invention include ethylene, propylene, butene-11, butene-12, isobutylene, pentene-11, pentene-12, hexene-1 and hexene. And hexene-13, heptene-11, heptene-12, heptene-13, various octenes, and mixtures thereof. Of these, α-olefins, especially ethylene, are preferred.

Ό ο

In the polymerization of the above-mentioned olefin, an inert solvent is usually used. Examples of such inert solvents include aliphatic hydrocarbons such as pentane, hexane, heptane and octane; alicyclic hydrocarbons such as cyclopentane, cyclohexane and methylcyclohexane; benzene, toluene, xylene, and the like. And aromatic hydrocarbons such as ethyl benzene. These solvents may be used singly or as a mixture of two or more.

The reaction temperature is usually in the range of 110 to 200, preferably in the range of 20 to 150 ° C. In the present invention, the optimal temperature depends on the type of electron donor used. Reaction temperatures are different. For example, when ethers such as dimethoxetane, tetrahydrofuran, and dioxane are used as the electron donor, the reaction temperature is preferably from 50 to 150, preferably from 80 to 130, and electron donation is preferably performed. When the cyclic or chain-like vinyl ether is used as an agent, the reaction temperature is preferably from 10 to 100, preferably from 20 to 80. Reaction pressure is usually atmospheric pressure Or ²⁰⁰ k / cm ² , preferably in the range of 5 to 10 O kg Z cm ² . Further, the charged amount of catalyst the chromium concentration of 1 0 _ ^3-5 0 Mi Rimoru Li Tsu Torr, preferably 1 0 - selected ^2-5 Mi Rimoru / "be in the range of Li tool bets Le.

The method of the present invention is preferably applied for simultaneously producing hexene-1 and octene-1 using ethylene as a raw material. That is, hexene-11 and octene-11 useful as a comonomer of linear low-density polyethylene can be selectively and efficiently produced by appropriately selecting catalyst production conditions and reaction conditions.

BEST MODE FOR CARRYING OUT THE INVENTION

Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

Preparation Example 1

Preparation of low hydrolysis aluminoxane (promoter A)

After replacing the inside of a separable three-neck flask with a volume of 500 milliliters equipped with a stirrer with nitrogen gas, 150 milliliters of toluene were added, and the contents of the flask were cooled in an ice-water bath. did. Next, 75 milliliters of triisobutylaluminum (TIBA) (58.95 g) was placed in a syringe, poured into a flask, and maintained for 10 minutes while continuing to stir in an ice-water bath. Thereafter, 9.32 g of aluminum sulfate '15 hydrate was added over 10 minutes.

Then, after stirring for 1 hour in an ice-water bath, the temperature was raised to 40 over 5 hours while changing to a water bath at 20 and adjusting the amount of generated gas. After the gas generation ceased from the liquid, the toluene was distilled off under a vacuum of 0.1 t0 rr. Thus, a low hydrolysis aluminoxane 34.7 was obtained. The hydrolysis rate was calculated according to the following equation.

1 0 0 R ₃ A 1 + 7 5 H 2 0 → 25 R _e A l ₄ 0 ₃ + 1 5 0 RH

Under the above hydrolysis conditions, a low hydrolyzed aluminoxane composed of an aluminum tetramer (average) is obtained on average.

This low-hydrolyzed aluminoxane was diluted with silk hexane to prepare a 1.2 mol liter solution.

Preparation Example 2

Preparation of triisobutylaluminoxane (promoter B)

Triisobutylaluminoxane was prepared in exactly the same manner as in Preparation Example 1, except that the amount of aluminum sulfate '15 hydrate used was changed from 9.32 g to 12.43 g. .0 g were obtained.

The hydrolysis rate was calculated according to the following equation.

1 0 0 R ₃ A l + 1 0 0 H ₂ O → 1 0 0 [RA l O] + 2 0 0 RH

Under the above hydrolysis conditions, an aluminoxane having a molecular weight of 100,000 or more is theoretically obtained.

This aluminoxane was diluted with a hexahedral hexane to prepare a 1.2 molar liter solution.

Preparation Example 3

Preparation of low hydrolyzed aluminoxane (dimer)

After replacing the inside of a separable three-neck flask with a 500-milliliter inner volume equipped with a stirrer with nitrogen gas, toluene 150 milliliters was added, and the contents of the flask were cooled with an ice-water bath. Cool. Next, take 75 milliliters of triisobutyl aluminum (TIBA) (58.95 g) into a syringe, pour into a flask, and continue stirring under an ice-water bath. After holding for 10 minutes, 6.8.4 g of aluminum sulfate '15 hydrate was added over 10 minutes.

Then, after stirring for 1 hour in an ice water bath, the temperature was raised to 40 ° C. over 5 hours while controlling the amount of generated gas by changing to a water bath of 20 cc. After the generation of gas ceased from the liquid, toluene was distilled off under vacuum. In this way, 44.7 g of a low hydrolysis aluminoxane was obtained.

The hydrolysis rate was calculated according to the following equation.

100 R ₃ A l + 55 H ₂ O → Main product R ₂ A 10 A 1 R _{2 Under the} above hydrolysis conditions, low hydrolysis aluminoxane consisting of aluminum dimer (average) on average Is obtained.

This low hydrolyzed aluminoxane 'is diluted with cyclohexane, and 1.3

A 3 molar liter solution was prepared.

Example 1

In a 200-Milliliter Erlenmeyer flask that has been dehydrated and deoxygenated, Cyclo (3) tris (2-ethylhexanoate (manufactured by STR EMC HEM ICALS, INC)) is placed under a nitrogen stream. Hexane solution (o. 0

0.45 milliliters of (11 Cr mole liter) (solution C) was added. Next, 0.07 g of 2,3-dihydrofuran was placed in a 100-milliliter Erlenmeyer flask prepared separately, and 42.5-milliliter of cyclohexane was added thereto ( This is D solution).

Next, while stirring the solution C, the solution D was dropped into the solution C. With stirring, 6.7 milliliters of the solution of cocatalyst A obtained in Preparation Example 1 was added to the mixture of the C and D solutions to prepare a catalyst solution. The total liquid volume at this time is 5

At 0 milliliters, the chromium concentration is 0.1 milliliters. Next, after the above-mentioned catalyst solution was poured into a 200-milliliter autoclave, which had been sufficiently degassed and dried, the content was stirred at 200 rpm, and the mixture was stirred at 40 rpm. Temperature. While maintaining the reaction temperature at 40, ethylene gas was fed in to maintain a pressure of 35 kgZcm ² · G. After reacting for 1 hour, it was cooled and depressurized. After filtering off the polymer from the reaction solution, the product was analyzed by gas chromatography, and it was found that hexene-11, octene-11 and oligomers having 10 to 20 carbon atoms were 1.94 g and 0.14 g, respectively. 54 g and 0.13 g were obtained. The selectivity of the oligomer product was 74.3% for hexene-1 and 20.3% for octene-11. Example 2

In Example 1, 2.25 milliliters of the chromium solution (solution C), 0.14 g of 2,3-dihydrofuran, and 10.0 milliliters of the solution of cocatalyst A were used. The procedure was performed exactly as in Example 1, except that the reaction time was 1.5 hours.

After filtering off the polymer from the reaction solution, the product was analyzed, and it was found that hexene-1, octene-1 and an oligomer having 10 to 20 carbon atoms were 0.71 g and 0.33, respectively. g and 0.01 g were obtained. The selectivity of oligomeric products was 67.6% for hexene-1 and 31.4% for octene-11.

Example 3

In Example 1, 3,4-dihydro-2H-pyran was used in place of 2,3-dihydrofuran, and 0.336 g of parenthesis was used, and 2.25 g of chrome solution (solution C) was used. The procedure was performed in exactly the same manner as in Example 1 except that the solution of the milliliter and cocatalyst A was changed to 6.7 milliliter and the reaction time was set to 45 minutes. After filtering off the polymer from the reaction mixture, the product was analyzed. As a result, hexene-1, octene-11 and an oligomer having 10 to 20 carbon atoms were 1.97 g and 0.28 g, respectively. g and 0.07 g were obtained. The selectivity of the oligomer product was 84.9% for hexene-1 and 12.1% for octene-11.

Example 4

In Example 1, 2,3-dihydrofuran was replaced by ethylvinyl ether, and 0.288 g of the parenthesis, 2.25 milliliters of chromium solution (solution C), and cocatalyst A The reaction was carried out in the same manner as in Example 1 except that the solution was changed to 6.7 milliliters and the reaction time was changed to 3.5 hours.

After filtering the polymer from the reaction mixture, the product was analyzed.Hexen-1, octene-11 and oligomers having 10 to 20 carbon atoms were 0.58 g and 0.17 g, respectively. And 0.02 g. The selectivity of the oligomer product was 75.3 octene-11 for hexene-1 and 22.0% for selectivity.

Example 5

In Example 1, 2,5-dihydrofuran was used instead of 2,3-dihydrofuran, 0.07 g of parenthesis was used, and 2.25 milliliters of chromium solution (solution C) was used. The reaction was carried out in exactly the same manner as in Example 1 except that the solution of the cocatalyst A was 5.0 milliliters and the reaction time was 1.5 hours.

After filtering off the polymer from the reaction mixture, the product was analyzed, and it was found that hexene-1, octene-1 and oligomers having 10 to 20 carbon atoms were 1.76 g and 0.2, respectively. 2 g and 0.02 g were obtained. The selectivities of the oligomer products were 88.0% for hexene-1 and 11.0% for octene-1. I got it.

Example 6

Erlenmeyer flask dehydrated and deoxygenated, chromium (3) bets Squirrel - hexane solution (0.1 0 cyclohexane (2 Kisanoe one preparative to E Chill) (: 1 "mol / ^/ l) (E solution) 8 milliliters were added, and 0.144 g of 2,3-dihydrofuran was added thereto (the resulting solution was referred to as solution F). Hexane hexane solution of isobutylaluminoxane (solution of co-catalyst B) 13.3 Milliliter and hexane solution of triisobutylaluminum (1.0 mol liter) 4.0 Milliliter Toluene was dropped into the above solution F. Cyclohexane was added to the catalyst solution thus obtained, and the total amount of the solution was adjusted to 50 milliliters.

Next, the above catalyst solution was charged into an autoclave having a sufficiently degassed and dried internal volume of 200 milliliters, and the content was stirred at 200 rpm, and then heated at 40 ° C. Temperature. While maintaining the reaction temperature 4 0 ^e C, forced in the E Chirengasu was maintained pressure of 9 kg / cm ² · G. 5. After reacting for 5 hours, it was cooled and depressurized. After filtering the polymer from the reaction solution and analyzing the product by gas chromatography, it was found that hexene-11, octene-11 and an oligomer having 10 to 20 carbon atoms were 0.68 g and 0.23 g, respectively. g and 0.04 g were obtained. The selectivity of the oligomer product was 71.6 octene-11 for hexene-1 and 24.296 for hexene-1. Example 7

In Example 6, the catalyst B solution was 6.7 milliliters, the hexane solution of triisobutylaluminum was 8 milliliters, and the autoclave was immersed in an ice water bath. The procedure was carried out in exactly the same manner as in Example 6, except that it was set to 10. After reacting for 2 hours, the reaction was stopped and the contents were analyzed. As a result of the analysis, 0.16 g, 0.10 g, and 0.14 g of hexene-1, octene-11, and an oligomer having 1.0 to 20 carbon atoms were obtained, respectively. The selectivity of the oligomer product was 40.0 octene-1 and 25.0% for hexene-1.

Example 8

In Example 6, chromium (3) tris (acetyl acetonato) was used in place of chromium (3) tris (2-ethylhexanoate), and 2,3-dihydrofuran was replaced with 0.28. The operation was carried out in exactly the same manner as in Example 6 except that the amount was changed to 8 g. After reacting for 2 hours, the reaction mixture was analyzed to find that hexene-1, octene-11 and oligomers having 10 to 20 carbon atoms were 0.56 g, 0.17 g and 0.2 g, respectively. 1 g was obtained. The selectivity of the oligomer product was 19.6% for hexene-1 and 18.1% for octene-11.

Example 9

To a dehydrated and deoxygenated 100-milliliter Schlenk tube, 0.24 g (0.5 mol) of chromium 2-ethylhexanoate (valence 3) was added under nitrogen flow. 46 g (360 millimoles) of toxetane were injected. Next, the Schlenk tube was immersed in a silicon oil bath at 80 ° C, and the solution in the tube was stirred under a stream of nitrogen under a stream of nitrogen for one milliliter of a solution of TIBA in cyclohexane. ) Was slowly added dropwise. After a lapse of 10 minutes from the dropping, the oil bath was lowered to 60 ° C, and dimethoxine in the Schlenk tube was distilled off under reduced pressure. When the internal solution reached about 5 milliliters, additional dimethoxetane was added to the internal solution, and the concentration was repeated. Finally, the content was reduced to about 5 milliliters (dimethoxetane 50%). (Millimol).

Next, the complex solution obtained by partially reducing the chromium complex in this manner is Diluted with hexane, the total complex fluid volume 5 0 ml and the _p Then, the Erlenmeyer flask 2 0 0 millimeter Li Tsu torr was dehydrated and deoxygenated, nitrogen gas flow, the chromium complex 3 Mi Lithium, partially hydrolyzed aluminoxane prepared in Preparation Example 3, mixed with 3.0 milliliters (aluminum: 4 millimoles) and cyclohexane 43.7 milliliters each As a result, a catalyst solution (total aluminum content: 4.3 mmol) was obtained. The catalyst solution eventually changed color from green (chromium valence 3) to yellow-brown (chromium valence 2).

In the production example of the present reduced chromium complex catalyst, aggregation of the divalent chromium complex is further suppressed by performing a two-step reduction treatment before and after the addition of the aluminumoxy compound.

Next, after charging the above catalyst solution (50 milliliters) into an autoclave with a sufficiently degassed and dried internal volume of 200 milliliters, the content was rotated at 200 rpm. The mixture was stirred and heated to 100. While maintaining the reaction temperature at 100, ethylene gas was fed in to maintain a pressure of 35 kg Z cm ² -G. After reacting for 23 minutes, it was cooled and depressurized. At this time, the amount of chromium in the reaction solution was 30 micromol, and the amount of dimethoxetane was 3 millimol. After filtering the polymer from the reaction solution, the product was analyzed by gas chromatography. The total reaction amount of ethylene was 4.07 g, and hexene-1, octene-11 and polymer were 3.13 g and 0, respectively. 1.2 g and 0.82 g were obtained. The selectivity of each product was 77% by weight of hexene-1, 3% by weight of octene-11 and 19% by weight of polymer. Comparative Example 1

Chromium 2-ethylhexanoate (valence 3) 0.25 g (0.5 mmol) and 6.3 g (50 mmol) of dimethoxetane are converted to cyclohexane. Dissolve to bring the total volume to 50 milliliters. This chromium complex solution was subjected to 3 milliliters (chromium: 30 micromoles, dimethyloxetane: 3 millimoles) without reduction treatment with an organic aluminum compound, and was subjected to dehydration and deoxygenation. Added to Milliliter Erlenmeyer flask. Next, the molar ratio of TIBA and water was set to 1, and a solution of an aluminum oxy compound obtained by hydrolyzing an organoaluminum compound in cyclohexane 3.2 milliliters (aluminum: 4.3 milliliters) Rimol) and cyclohexane (43.7 milliliters) were mixed to obtain 50 milliliters of a blue catalyst solution. Then, in the same manner as in Example 1, the above catalyst solution was injected into the autoclave, and ethylene was reacted. However, no reaction occurred.

Example 10

A catalyst solution was prepared in exactly the same manner as in Example 9 except that the mixed amount of the dilute solution of the reduced chromium complex was changed from 3 milliliters to 2 milliliters in Example 9. The reaction of ethylene was performed. 86 minutes after the start of the reaction, the reaction was stopped and the contents were analyzed.The total reaction amount of ethylene was 3,95 g, and hexene-1, octene-1 and bolimer were 2.81 and 0. 15 g and 0.999 g were obtained. The selectivity of each product was 71% by weight for hexene-1, 4% for octene-11, and 25% by weight for polymer.

Example 1 1

In Example 10, the amount of the partially hydrolyzed organic aluminum prepared in Preparation Example 3 was changed from 3.0 milliliters (aluminum: 4 millimoles) to 4.5 milliliters (aluminum: 6 millimoles). ) Was prepared in exactly the same manner as in Example 10 except that) was used, and the ethylene was reacted. 13 minutes after the start of the reaction, the reaction was stopped and the contents were analyzed. The total reaction amount of ethylene was 3.94 g, and hexene-11, octene-11 and bolimer were obtained in 2.21, 0.15 g and 1.58 g, respectively. The selectivity of each product was hexene-1 (56% by weight), octene-11 (3% by weight), and polymer (40% by weight).

Reference example 1

In Example 10, the amount of the partially hydrolyzed aluminum prepared in Preparation Example 3 was changed from 3.0 milliliters (aluminum: 4 millimoles) to 2.3 milliliters (aluminum: 3 milliliters). A catalyst solution was prepared in exactly the same manner as in Example 10 except that the reaction was carried out with the reaction of ethylene. The temperature was lowered 120 minutes after the start of the reaction, and the contents were analyzed, but only the amount of the trace of the polymer was detected. The color of the adjusted catalyst was a color peculiar to the trivalent chromium carboxylate complex, and the liquid after the reaction was also a color vitreous, which was not reduced.

Example 1 2

To a dehydrated and deoxygenated 200-milliliter Erlenmeyer flask was placed 0.45 ml of a cyclohexane solution (solution A) of chromium 2-ethylhexanoate (valence 3) in a nitrogen stream. Little (chromium content 5 micromol) was injected. Next, 0.14 g (2 mmol) of 2,3-dihydrofuran was weighed into a separately prepared Erlenmeyer flask. To this was added 42.8 milliliters of cyclohexane (Solution B). Then, while stirring the solution A, the solution B was dropped into the solution A. While the stirring was continued, the partially hydrolyzed organoaluminum obtained in Preparation Example 3 was further added to the mixed solution of the solution A and the solution B in an amount of 6 milliliters (aluminum: 8 millimoles). The catalyst solution obtained in this way turned from a peculiar color of chromium carboxylate (chromium valence 3) to an ocher color (chromium valence 2) (partially hydrolyzed to an organic aluminum compound; Not unreacted TIBA Included, which reduced the chromium compound).

Next, in the same manner as in Example 9 except that the reaction temperature was changed from 100 to 40, 50 milliliters of the catalyst solution was injected into the autoclave, and ethylene was reacted. . At this time, the amount of chromium in the catalyst solution was 5 micromol and the amount of dihydrofuran was 2 millimol. The reaction was stopped 102 minutes after the start of the reaction, and cooled. As a result, hexene-1, octene-1 and a polymer were obtained in 2.9 g, 0.25 g, and 1.85 g, respectively, of the total reaction product of ethylene in 5.0 g. The selectivity of each product was 58% by weight for hexene-1, 5% by weight for octene-11, and 37% by weight for polymer.

Example 13

In Example 9, 0.24 g (0.5 millimol) of 2-ethylhexanoic acid (valence 3) and 0.66 of dimethoxetane were placed in a Schlenk tube of 100 milliliters. g (5.0 millimoles) was injected. Next, the Schlenk tube was immersed in a silicon oil bath at 80 ° C, and 5 milliliters (5 millimoles) of a 1-milliliter solution of TiBA in the mouth of TiBA was gradually added dropwise. After the dropwise addition, it kept for 10 minutes 8 0 ^e C, then cooled to room temperature.

Next, the complex solution obtained by partially reducing the chromium complex in this manner was diluted with xylene to make a total amount of 50 milliliters. The subsequent experimental operation was performed in the same manner as in Example 9.

The reaction took 4.5 hours. At this time, the amount of chromium in the reaction solution was 30 micromoles and the amount of dimethoxetane was 0.3 millimoles. The total reaction amount of ethylene was 3.87 g, and 1.74 g, 0.10 g, and 2.03 g of hexene-1, octene-11, and polymer were obtained, respectively. The selectivity of each product was 45% by weight for hexene-1, 3% by weight for octene-1, The polymer was 52% by weight.

In this example, the amount of dimethoxetane used was small, the reaction time was slower than in Example 9, and the oligomer yield tended to be low.

Industrial applicability

By the method for producing the oligomer of the present invention, and the reduced chromium complex catalyst and the method for producing the reduced chromium complex used in the method, hexene-11 and octene useful as a comonomer of linear low-density polyethylene (L-LDPE) are obtained. Can be selectively and efficiently manufactured

Claims

The scope of the claims

1. In the coexistence of an electron donor, the trivalent compound having an oxygen anion as a ligand reduces at least one of hexavalent chromium compounds with a reducing agent and reduces the valence of chromium to divalent. Method for producing reduced chromium complex to obtain complex o

2. The method for producing a reduced chromium complex according to claim 1, wherein the electron donor is used in a molar ratio of 20 or more to the chromium compound.

3. Manufacture of a reduced chromium complex catalyst characterized by mixing at least one of a trivalent or hexavalent chromium compound having an electron donor and an oxygen anion as a ligand, and a reducing agent and an aluminum oxy compound. Method.

4. A method for producing a reduced chromium complex catalyst, comprising adding an aluminoxy compound after producing the reduced chromium complex according to claim 1 or 2.

5. A process for producing an olefin oligomer, which comprises reacting an olefin in the presence of a reduced chromium complex catalyst obtained by using the production method according to claim 3 or 4. .

6. The method for producing an oligomer of claim 5, wherein the oligomer is ethylene.

7. The electron donor is a cyclic ether, a chain chain ether, a cyclic vinyl ether, a chain vinyl ether, a cyclic aryl ether, a chain aryl ether, an aliphatic amine, or an aromatic amine. 7. The method for producing an oligomer according to claim 5 or 6, wherein the method is at least one selected from the group consisting of a compound and a heterocyclic compound.

8. The method according to claim 5, wherein the electron donor is selected from the group consisting of tetrahydrofuran, dimethoxetane, 2,3-dihydrofuran and 3,4-dihydro-1 2H-pyran. Item 8. The method for producing an oligomer according to any one of Item 7.

9. The method according to any one of claims 5 to 8, wherein the electron donor is used in a molar ratio of 20 to 1000 with respect to the chromium compound. A method for producing the above-mentioned oligomer.

1 0. The aluminum Niumuokishi compound, water / ^/ aluminum compound = 0.2 to 1.1 Claim 5 which is a reaction product of Aruminiumu compound and water is (molar ratio) to the 10. The method for producing an oligomer according to any one of items 9 to 10.

11. The method according to claim 5, wherein the aluminumoxy compound is used in a molar ratio of 1 to 1000 with respect to the chromium compound. The method for producing the oligomer described in (1).

12. The method for producing an olefin oligomer according to any one of claims 5 to 11, wherein the reducing agent is an organic aluminum.