KR19980075888A - Process for preparing alpha olefin oligomer - Google Patents

Abstract

The present invention is a method of low polymerization of an alpha olefin in a reaction solvent of aliphatic saturated hydrocarbons using a catalyst composed of a Cr compound, an amide containing compound and an alkylaluminum compound, wherein the low polymerization reaction is carried out in the presence of an aromatic hydrocarbon compound containing a halogen group. It is related with the low-polymerization method of alpha olefin characterized by performing.

According to the method of the present invention, a high purity alphaolefin polymer, especially hexene-1, is maintained by a reaction proceeding to high activity while maintaining high selectivity of hexene-1 and improving the initial activity of the catalyst and the aging phenomenon over time. Obtained as a product.

Description

Process for preparing alpha olefin oligomer

The present invention relates to a method for preparing an oligomer of an alpha olefin, such as hexene-1, and more particularly, by using a catalyst having improved activity compared to the conventional method, the industrially advantageous alpha olefin low with high yield and selectivity A method for producing a polymer.

Conventionally, a low polymerization method of alpha olefins such as ethylene and the like is generally known, in which an organoaluminum compound is suitably blended with a specific Cr compound containing pyrrole and brought into contact with a specific unsaturated hydrocarbon to advance the reaction. Such a catalyst system is particularly effective in trimerization of olefins and, for example, was used as a catalyst for trimming ethylene to produce hexene-1 and the like. However, the catalyst of this method is generally low in activity and low in reaction yield, and the rate of decrease in catalyst activity over time is high, thus increasing the amount of catalyst input. Therefore, various methods have been developed to improve this.

For example, European Patent EP 668105 describes a method for improving the rate of decrease in activity over time by utilizing alkyl substituted aromatic compounds as cocatalysts. By this method, the problem of aging of the catalyst was somewhat improved, but the initial activity of the catalyst was the same as when no promoter was used, and the overall reaction yield was not sufficiently increased.

In addition, Japanese Patent Application Laid-open No. Hei 7-18013 discloses a method for reducing the amount of polymer produced and improving the activity of a catalyst by performing low polymerization in the presence of an aromatic hydrocarbon compound having three or more aliphatic hydrocarbon substituents. The low selectivity to hexene in the total product (selectivity 55.5%) was not suitable when preparing hexene-1.

EP 0 614865 A1 was intended to provide a method for improving the catalytic activity as well as improving the selectivity of hexene, but the activity of the catalyst used therein was not satisfactory.

Accordingly, it is an object of the present invention to improve the initial activity of the catalyst and to slow down the rate of decrease of activity over time while maintaining the selectivity of hexene-1 in the preparation of alpha olefins, in particular hexene-1. It is to provide a method for producing an alpha olefin oligomer which can reduce the amount of to be added and can sufficiently increase the production yield of the desired alpha olefins per hour.

In order to achieve the above object, according to the present invention, using a catalyst composed of 1) Cr compound, 2) amide containing compound, and 3) alkylaluminum compound, in the presence of an aromatic hydrocarbon compound containing a halogen group, A method of making a polymer is provided.

Hereinafter, the content of the present invention will be described in detail.

The catalyst according to the present invention may be prepared by preparing a solution containing a Cr compound and an amide-containing compound in advance, and introducing an alkylaluminum compound thereto. The starting material alpha olefin is ethylene and the main product is hexene-1. It is preferable.

The Cr catalyst is a compound represented by CrXmYn, and has 2 to 6 oxidation numbers, X represents alkyl, alkoxy, ketone, carboxyl group and halogens, and Y represents amine, phosphine, phosphine oxide, nitrosyl group and ether. M is an integer of 2-4, n is an integer of 0-4.

The alkyl here is a hydrocarbon having 1 to 20 carbon atoms. The alkoxy may be any alkoxy group having 1 to 20 carbon atoms.

The ether may be any aliphatic and / or aromatic hydrocarbon compound having a structure of R-O-R. Wherein the R groups may be the same or different. Since aromatic ether is harmful to human body, R is preferably aliphatic hydrocarbon. Suitable examples include tetrahydrofuran, dioxin, diethyl ether, dimethoxyethane, diglyme, tri-glyme and the like.

As the ketone, di-ketone is preferable, and among these, 1,3-di-ketone having 5 to 30 carbon atoms is more preferable.

The carboxyl group is preferably a compound having 1 to 20 carbon atoms, and examples thereof include 2-ethylhexanoic acid, acetic acid, butyric acid, neopentanoic acid, lauric acid, stearic acid, acetoacetic acid, oxalic acid, cycloalkanoic acid, naphthenic acid, and the like. Can be mentioned.

As the halogen, chlorine, bromine, iodine, fluorine can be used, and chlorine is particularly preferable.

As the amine, pyrroles or pyridines are mainly used, preferably pyrrole, 2,5-dimethylpyrrole, pyridine, 4-ethylpyridine, 4-isopropylpyridine and 4-phenylpyridine. Phosphine, phosphine oxide, nitrosyl group, etc. may use any commercialized product.

Examples of the Cr compound include chromium tris (2-ethylhexanoate), chromium bis (2-ethylhexanoate), chromium tris (naphthenate), chromium bis (naphthenate), chromium tris (acetate), Chromium bis (acetate), chromium tris (acetylacetonate), chromium trichlorotripyridine, chromium trichlorotritetrahydrofuran and the like.

As the compound containing an amide, any amide containing compound capable of reacting with a Cr compound to produce a Cr-amido compound can be used. At this time, as long as an amide produces | generates the organic radical containing nitrogen, any can be sufficient, and the amide compound of C1-C20 is generally preferable. Examples of compounds containing suitable amides include lithium dimethylamide, lithium diethylamide, lithium diisopropylamide, lithium bicyclohexylamide, sodium bis (trimethylsilyl) amide, sodium indolide, lithium pyrrolide, sodium pyrrolide Potassium pyrrolide, cesium pyrrolide, diisopropylaluminum pyrrolide, diethylaluminum pyrrolide, dietary butylaluminum pyrrolide, lithium 2,5-dimethylpyrrolide, sodium 2,5-dimethylpyrrolide, potassium 2, 5-dimethylpyrrolide, cesium 2,5-dimethylpyrrolide, diisopropylaluminum 2,5-dimethylpyrrolide, diethylaluminum 2,5-dimethylpyrrolide, dietary butylaluminum 2,5-dimethylpyrrolide, etc. Can be mentioned.

Alkyl aluminum compounds may be triethylaluminum, tripropylaluminum, tributylaluminum, diethylaluminum chloride, diethylaluminum bromide, ethylaluminum sesquichloride, or a combination thereof, increasing the activity of the catalyst and the selectivity of the product. In order to do this, it is preferable to use triethyl aluminum.

As the reaction solvent of the present invention, aliphatic saturated hydrocarbons are used, and the reaction proceeds by further mixing an appropriate amount of the aromatic hydrocarbon compound containing the halogen group with a solvent and contacting the alpha olefin.

As the saturated hydrocarbons, aliphatic saturated hydrocarbons having 4 to 12 carbon atoms may be used, but an appropriate one may be selected in consideration of separation from the product.

In the present invention, the aromatic compound including a halogen group which is a solvent added further includes one or a mixture of aromatic hydrocarbons in which 1 to 6 halogen atoms are substituted on adjacent 1 to 6 carbon atoms of a benzene ring having 6 carbon atoms. desirable. In this case, the halogen group refers to chlorine, bromine, iodine and fluorine. Specific examples of the aromatic compound containing a halogen group are as follows.

One hydrogen of benzene is benzene substituted with a halogen group, and the halogen group may be any of chlorine, bromine, iodine and fluorine. Two halogen groups are compounds substituted with 1,2 or 1,3 or 1,4 positions of benzene, and the halogen group may be any one of chlorine, bromine, iodine and fluorine, and the two halogens may be different from each other. A compound in which three hydrogens of benzene are substituted with three halogens and 1,2,4 or 1,2,5 or 1,3,5, and the halogen group may be any one of chlorine, bromine, iodine and fluorine, and three halogens May be different.

Suitable aromatic compounds containing such halogen groups are chlorobenzene, fluorobenzene, 1,2-dichlorobenzene, 1,2-difluorobenzene, 1,4-dichlorobenzene, 1,4-difluorobenzene, 1 , 2,4-trichlorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trichlorobenzene, 1,3,5-trifluorobenzene, and the like, among which chlorobenzene , 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene are particularly preferred.

In general, the aromatic hydrocarbon compound or a mixture thereof including a halogen group to be added to the reactor is preferably 50% by volume or less based on the total amount of the solvent. More preferably, the aromatic hydrocarbon compound containing a halogen group or a mixture thereof in contact with the catalyst system is in the range of about 20 to 35% by volume based on the total amount of solvent introduced. In more detail, the amount of the aromatic hydrocarbon compound containing a halogen group or a mixture thereof is preferably about 6000 mol or less, expressed in terms of the number of moles of the aromatic hydrocarbon compound containing a halogen group per unit mole of Cr compound included in the catalyst system. 2000 to 3500 moles are more preferred, and 2100 to 3400 moles are even more preferred.

If the aromatic hydrocarbon containing the halogen group is too much or too small, not only the initial activity of the catalyst is lowered, but also the rate of decrease of the catalyst activity over time can be increased.

The present invention is explained in more detail by the following examples. However, these examples are provided to aid the understanding of the present invention, and the scope of the present invention in any form is not limited by these examples.

Example 1

CrCl ₃ [N ₁ C ₅ H ₅ ] ₃ 0.0594 g / 10 ml n-heptane solution (0.15 mmol) with distilled-butyl aluminum 2,5-dimethylpyrrolide (hereinafter referred to as DIBAMP) 0.1420 g / 10 ml n-heptane A solution (0.60 mmol) was added in an ice bath at about 0 to 5 ° C., and after reacting for about 2 hours, 1.05 ml (1.05 mmol) of 1M triethylaluminum solution dissolved in n-heptane was added thereto. Then, after reacting for about 0.5 hours, the prepared catalyst solution was introduced into a 1 L reactor in which water and oxygen were completely removed in the presence of ethylene. Then, 145 ml of n-heptane was injected into the solvent, and 35 ml of chlorobenzene was injected to fix the total amount of solvent to 180 ml. After the temperature was raised to 100 degrees Celsius, the reaction pressure of ethylene was raised to 600 psi, and the reaction was started. The pressure of ethylene was maintained at 600 psi during the reaction, and the consumption of ethylene was measured during the reaction. Based on the amount of alpha olefins produced after the reaction was completed, activity was calculated relative to ethylene consumption at 30, 60, or 90 minutes. The product was analyzed by GC.

Example 2

The same procedure as in Example 1 was conducted except that 128 ml of n-heptane and 55 ml of chlorobenzene were used as a solvent.

Example 3

The same procedure as in Example 1 was conducted except that 151 ml of n-heptane and 35 ml of 1,2,4-trichlorobenzene were used as the solvent.

Example 4

The same procedure as in Example 1 was conducted except that 137 ml of n-heptane and 45 ml of 1,2-dichlorobenzene were used as the solvent.

Comparative Example 1

The same procedure as in Example 1 was carried out except that 162 ml of n-heptane was used as the solvent.

Comparative Example 2

The same procedure as in Example 1 was conducted except that 114 ml of n-heptane and 45 ml of toluene were used as the solvent.

Comparative Example 3

The same procedure as in Example 1 was conducted except that 123 ml of n-heptane and 45 ml of mesitylene were used as a solvent.

Comparative Example 4

The same procedure as in Example 1 was conducted except that 168 ml of n-heptane and 15 ml of chlorobenzene were used as a solvent.

Comparative Example 5

The same procedure as in Example 1 was conducted except that 85 ml of n-heptane and 90 ml of chlorobenzene were used as a solvent.

Comparative Example 6

The procedure was the same as in Example 1 except that 158 ml of n-heptane and 25 ml of 1,2,4-trichlorobenzene were used as the solvent.

Comparative Example 7

The same procedure as in Example 1 was carried out except that 111 ml of n-heptane and 65 ml of 1,2,4-trichlorobenzene were used as the solvent.

Comparative Example 8

The same procedure as in Example 1 was conducted except that 146 ml of n-heptane and 35 ml of 1,2-dichlorobenzene were used as the solvent.

Comparative Example 9

The procedure was the same as in Example 1, except that 105 ml of n-heptane and 75 ml of 1,2-dichlorobenzene were used as the solvent.

Test results for the above Examples and Comparative Examples are shown in Table 1 and Table 2.

TABLE 1

Example 1 Example 2 Example 3 Example 4 Solvent used Type of input solvent (A) n-heptane n-heptane n-heptane n-heptane Input amount of solvent (A) (ml) 145 128 151 137 Type of input solvent (B) CB CB TCB DCB Input amount of solvent (B) (ml) 35 55 35 45 Response time (hours) 0.5 C ₆ production amount / g 88.7 97.74 107.9 120.5 Catalytic Efficiency (g / g-Cr) 11363 12458 13707 15437 Activity (g / g-Cr.HR) 22726 24916 27414 30874 1.0 C ₆ production amount / g 188.25 207.1 192.5 214.1 Catalytic Efficiency (g / g-Cr) 24115 26397 24454 27427 Activity (g / g-Cr.HR) 24115 26397 24454 27427 1.5 C ₆ production amount / g 277.3 305.9 248.9 279 Catalytic Efficiency (g / g-Cr) 35523 38990 31619 35741 Activity (g / g-Cr.HR) 23682 25993 21079 23827 High polymer yield (% by weight) 0.10 0.21 0.21 0.14 Hexene-1 purity (% by weight) 99.2 99.3 98.9 98.97 C ₆ selectivity (% by weight) after completion of reaction 85.7 87.6 84.8 94 CB: chlorobenzene, TCB: 1,2,4-trichlorobenzene, DCB: 1,2-dichlorobenzene

TABLE 2a

Comparative Example 1 Comparative Example 2 Comparative Example 3 Solvent Type of input solvent (A) n-heptane n-heptane n-heptane Input amount of solvent (A) (ml) 162 114 123 Type of input solvent (B) none toluene Mesitylene Input amount of solvent (B) (ml) 0 45 45 Response time (hours) 0.5 C ₆ production amount / g 51.17 15.1 17 Catalytic Efficiency (g / g-Cr) 6544 1934 2153 Activity (g / g-Cr.HR) 13088 3868 4306 1.0 C ₆ production amount / g 93.01 23.2 37 Catalytic Efficiency (g / g-Cr) 11895 2972 4685 Activity (g / g-Cr.HR) 11895 2972 4685 1.5 C ₆ production amount / g 129.1 Stop the reaction Stop the reaction Catalytic Efficiency (g / g-Cr) 16510 Activity (g / g-Cr.HR) 11007 High polymer yield (% by weight) 0.63 7.98 2.09 Hexene-1 purity (% by weight) 98.5 99 99.4 C ₆ selectivity (%) after completion of reaction 82.9 57 73.5

TABLE 2b

Comparative Example 4 Comparative Example 5 Comparative Example 6 Comparative Example 7 Comparative Example 8 Comparative Example 9 Solvent Type of input solvent (A) n-heptane n-heptane n-heptane n-heptane n-heptane n-heptane Input amount of solvent (A) (ml) 168 85 158 111 146 105 Type of input solvent (B) CB CB TCB TCB DCB DCB Input amount of solvent (B) (ml) 15 90 25 65 35 75 Response time (hours) 0.5 C ₆ production amount / g 51 no response 85.6 47 74.6 74.1 Catalytic Efficiency (g / g-Cr) 6489 10812 6021 9557 9509 Activity (g / g-Cr.HR) 12979 21604 12042 19114 19018 1.0 C ₆ production amount / g 92.5 91.9 Interruption of reaction (extinction of catalyst activity) 100.94 94.4 Catalytic Efficiency (g / g-Cr) 11770 11597 12931 12114 Activity (g / g-Cr.HR) 11770 11597 12931 12114 1.5 C ₆ production amount / g 115 Interruption of reaction (catalyst activity disappears) 114.6 Interruption of reaction (catalyst deactivation) Catalytic Efficiency (g / g-Cr) 14633 14681 Activity (g / g-Cr.HR) 9755 9787 High polymer yield (% by weight) 0.35 - 0.32 2.53 0.73 0.51 Hexene-1 purity (% by weight) 97.3 - 97.6 98.3 98.7 98 C ₆ selectivity (%) after completion of reaction 81.9 - 91.9 88.8 83 86.3

In the above table, each comparison item was obtained through the following equation.

Catalytic efficiency =

Active =

High polymer yield x 100 (%)

Hexene-1 purity = x 100 (%)

C ₆ selectivity = x 100 (%)

According to the method of the present invention, a high purity alphaolefin polymer, especially hexene-1, is maintained by a reaction proceeding to high activity while maintaining high selectivity of hexene-1 and improving the initial activity of the catalyst and the aging phenomenon over time. Obtained as a product.

Claims (10)

A method for low polymerization of an alpha olefin in a reaction solvent of aliphatic saturated hydrocarbons using a catalyst composed of a Cr compound, an amide containing compound, and an alkylaluminum compound, characterized by performing a low polymerization reaction in the presence of an aromatic hydrocarbon compound containing a halogen group. Low polymerization method of alpha olefin to be used. According to claim 1, wherein the aromatic hydrocarbon compound containing a halogen group is one of aromatic hydrocarbon compounds in which 1 to 6 halogen atoms are substituted in adjacent 1 to 6 carbon atoms of the benzene ring having 6 carbon atoms, or a mixture thereof Low polymerization method of alpha olefin, characterized in that. The compound according to claim 1 or 2, wherein the aromatic hydrocarbon compound is chlorobenzene, fluorobenzene, 1,2-dichlorobenzene, 1,2-difluorobenzene, 1,4-dichlorobenzene, 1,4-di Characterized in that selected from fluorobenzene, 1,2,4-trichlorobenzene, 1,2,4-trifluorobenzene, 1,3,5-trichlorobenzene, 1,3,5-trifluorobenzene Low polymerization method of alpha olefin to be. According to claim 3, wherein the aromatic hydrocarbon compound is selected from chlorobenzene, 1,2-dichlorobenzene, 1,4-dichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene Low polymerization method of alpha olefin characterized by the above-mentioned. The method according to any one of claims 1 to 4, wherein the amount of the aromatic hydrocarbon compound or a mixture thereof is 50% by volume or less based on the total solvent amount. 6. The method of claim 5, wherein the amount of the aromatic hydrocarbon compound or mixture thereof is 20 to 35% by volume based on the total solvent amount. The method according to any one of claims 1 to 4, wherein the amount of the aromatic hydrocarbon compound or a mixture thereof is 6000 mol or less per unit mole of Cr compound included in the catalyst. 8. The method of claim 7, wherein the amount of the aromatic hydrocarbon compound or a mixture thereof is in the range of 2000 to 3500 moles per mole of Cr compound included in the catalyst. 9. The method of claim 8, wherein the amount of the aromatic hydrocarbon compound or mixture thereof is in the range of 2100 to 3400 moles per mole of Cr compound contained in the catalyst. 10. The method according to any one of claims 1 to 9, wherein the starting material alpha olefin is ethylene and hexene-1 is obtained as the main product.