JPH0892163A - 3-methoxypropionic acid ester derivative - Google Patents

Abstract

PURPOSE: To obtain the new compound having an ester and an alkoxy in the molecule, having an alkyl-substituent group, particularly a bulky substituent group on carbon atom at α-position numbering from the ester and useful as an electron donating compound of a Ziegler-Natta catalyst. CONSTITUTION: A 3-methoxy-2-isopropyl-2-isopentylpropionic acid alkyl ester of formula I (R is a 1-4C lower alkyl), e.g. 3-methoxy-2-isopropyl-2- isopentylpropionic acid ethyl ester, etc. The compound of formula I is obtained by reacting, e.g. a 3-hydroxy-2-isopropyl-2-isopentylpropionic acid alkyl ester with a methyl halide or methyl paratoluenesulfonate in the presence of a dehalogenating agent. The ester of formula II or formula III is useful as an intermediate for compound of formula I.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a novel 3-methoxy-2
-Isopropyl-2-isopentylpropionic acid alkyl ester, a process for producing the same, and compounds useful as electron donors of Ziegler-Natta catalysts for producing polyolefins.

[0002]

2. Description of the Related Art A Ziegler-Natta catalyst, which is conventionally used for the production of polyolefins and mainly composed of an organoaluminum compound and a transition metal compound of Groups 3 to 5, is a group having an electron-donating group in order to improve its activity. It is used by blending a compound having The detailed reason for this improvement in activity is not known at present, but according to recent research, in order to improve the performance of the catalyst, the electron-donating compound used is (1) an ester group in the molecule. And having an alkoxy group. (2) The molecule has a large substituent that causes steric hindrance. Has been deemed necessary.

Based on the above assumptions, the present inventors previously used the general formula R ¹ —O—CH ₂ —CH (R ³ ) COOR ² (wherein R ^{1 to} R ³ are alkyl groups). Indicated 3
It was confirmed that when an -alkoxy-2-alkyl-substituted propionic acid ester is used as an electron-donating compound for a Ziegler-Natta catalyst, a certain degree of improved catalytic performance can be exhibited (JP-A-2-289604). .
However, many electron-donating compounds that have been proposed so far, including the above-mentioned electron-donating compounds, have not always satisfied high industrial requirements for high catalytic activity, high stereoregularity, and productivity. .

In order to further improve the performance of the Ziegler-Natta catalyst, the present inventors have an ester group and an alkoxy group in the molecule and have an α of the ester group.
It was estimated that the use of a compound having two bulky alkyl groups on the position carbon atom as an electron-donating compound is one of the possible solutions. These compounds have not been reported in the literature, probably because of the steric hindrance of the bulky alkyl group substituted at the α-position of the ester group, or because the use could not be imagined at all. Based on the above estimation, the present inventors have an ester group and an alkoxy group in the molecule, and an alkyl group on the carbon atom at the α-position of the ester group,
A new compound having two particularly bulky alkyl substituents was sought.

[0005]

DISCLOSURE OF THE INVENTION The present invention has an ester group and an alkoxy group in the molecule, and has an α group of the ester group.
3-methoxy-2-isopropyl-2- as a compound having two bulky substituents on the carbon atom at position
The purpose of the present invention is to develop isopentyl propionate and its manufacturing method. They are compounds useful as electron donors for Ziegler-Natta catalysts that exhibit high activity and high stereoregularity.

[0006]

The present invention is based on the general formula (1)

[Chemical 4] (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
In the presence of a dehalogenating agent, 3-methoxy-2-isopropyl-2-isopentylpropionic acid alkyl ester or 3-hydroxy-2-isopropyl-2-isopentylpropionic acid alkyl ester represented by 3-Methoxy-2-isopropyl-characterized by reacting methyl toluenesulfonate
Method for producing 2-isopentylpropionic acid alkyl ester and 3-methoxy-2-isopropyl-2, which comprises reacting a 3-methoxy-2-isopropyl-2-isopentylpropionic acid compound with an alcohol
The above objectives have been achieved by developing a process for the preparation of isopentylpropionic acid alkyl esters.

Further, 2-formyl-2-isopropyl- represented by the general formula (2), which is an intermediate of 3-methoxy-2-isopropyl-2-isopentylpropionic acid alkyl ester represented by the general formula (1). 5-Methyl-hexanoic acid alkyl ester.

[Chemical 5] (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
And 3-hydroxy-2-isopropyl-2-isopentylpropionic acid alkyl ester represented by the general formula (3).

[Chemical 6] (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
Are both new compounds.

The present invention will be described below by taking 3-methoxy-2-isopropyl-2-isopentylpropionic acid ethyl ester as a representative. The ethyl ester is, for example, 3
- hydroxy-2-isopropyl-2-isopentyl propionate in a solvent in the presence a dehydrohalogenation agent, (wherein, X is chlorine, bromine, iodine, p-toluenesulfonic acid) CH ₃ X is reacted with Thus, a crude product can be obtained. As the solvent, a protic solvent such as alcohol and a polar solvent such as ether are effective. As the dehydrohalogenating agent coexisting at this time, sodium, potassium, sodium hydride, potassium hydride, or the like can be used. CH ₃ X is preferably methyl iodide, methyl bromide or methyl chloride. Usually, after adding methyl halide, the reaction may be performed at a temperature of 20 to 200 ° C. for 1 to 24 hours.

In the above, 3-to be used as a raw material
Ethyl hydroxy-2-isopropyl-2-isopentylpropionate can be synthesized by the reduction reaction of the corresponding aldehyde compound. For example, the desired product can be obtained by reacting ethyl 2-formyl-2-isopropyl-5-methyl-hexanoate with an organometallic compound in a solvent. Alcohol or the like is effective as the solvent. As the organometallic compound, a compound having a weak reducing power is generally preferable, and sodium boron hydride or the like is effective. Usually 1-2 at a temperature of -78 ° C to 200 ° C
Allow to react for 4 hours. The ethyl 2-formyl-2-isopropyl-5-methyl-hexanoate can be produced by utilizing the Cannitzro reaction between 2-isopropyl-2-isopentyl-ethyl acetate and alkaline formaldehyde.

2-formyl-2-isopropyl-5
As an alternative method for synthesizing -methyl-ethyl hexanoate, it can be synthesized by a selective partial reduction reaction of the corresponding diester compound. As a specific method, it is possible to produce the target product by reacting diethyl 2-isopropyl-2-isopentylmalonate with an organometallic compound in a solvent. As the solvent, a polar solvent such as ether, a hydrocarbon solvent such as hexane, or an aromatic hydrocarbon solvent such as toluene can be used. As the organometallic compound, sodium aluminum hydride, lithium aluminum alkoxide, diisobutylaluminum, hydrosilane, hydrotin or the like can be used, but a diisobutylaluminum compound or the like is preferable. The temperature at which the organometallic compound is contacted is -100 ° C to 50 ° C,
The temperature is preferably −78 ° C. to 0 ° C. The reaction time varies depending on the type of organometallic hydride used, but is usually 1
Hours to 24 hours.

2-formyl-2-isopropyl-5-
Methyl-hexanoate alkyl has the general formula (4)

[Chemical 7] Depending on the general synthetic method for partial reduction of the diester compound shown in, when the alkyl group of R ₁ and R ₂ is small (for example, when both R ₁ and R ₂ are isobutyl groups), partial reduction is performed. It has been extremely difficult to produce 2,2-dialkyl substituted 2-formyl-acetic acid ester. However, when R ₁ and R ₂ were a combination of an isopropyl group and an isopentyl group, reduction with an organometallic compound could selectively reduce one of the dicarboxylic acids and stop at the aldehyde stage. It can also be synthesized by an esterification reaction of 3-methoxy-2-isopropyl-2-isopentylpropionic acid or its acid chloride instead of methoxylation of the 3-position hydroxyl group. For example, 3-methoxy-2-isopropyl-
A crude product can be obtained by reacting 2-isopentylpropionic acid with ethanol in the presence of a catalyst.

The target product can be obtained by distilling and purifying the crude product thus obtained. Purified 3
Ethyl -methoxy-2-isopropyl-2-isopentylpropionate has a boiling point of 126.5-127 ° C / 13.
mmHg colorless liquid, ¹ H-NMR, ¹³ C-N
It can be confirmed by MR, GC-MS or the like. For example, when analyzed using ¹ H-NMR, (1) a signal of a hydrogen atom bonded to a carbon atom directly bonded to an oxygen atom in the ethyl group of the ester group at δ = 4.096 ppm (2 ) At δ = 3.472 ppm, the signal of the hydrogen atom located at the 3-position of the propane skeleton (3) δ = 3.273 ppm At the signal of the hydrogen atom bonded to the carbon atom of the methoxy group (4) At δ = 1.948 ppm Signal of hydrogen atom bonded to carbon atom on methine group of isopropyl group (5) Signal of hydrogen atom bonded to carbon atom on methylene group of isopentyl group at δ = 1.663-1.570 ppm (6) δ = Signal of hydrogen atom bonded to carbon atom on methine group of isopentyl group at 1.446 ppm (7) Methyl carbon of ethyl group of ester group at δ = 1.214 ppm Signal of hydrogen atom bonded to atom (8) Signal of hydrogen atom bonded to carbon atom on methylene group of isopentyl group at δ = 1.149-1.087 ppm (9) δ = 0.96-0 Signal of hydrogen atom bonded to carbon atom on methylene group of isopentyl group at 927 ppm (10) δ = 0.8 Signal of hydrogen atom bonded to carbon atom on methyl group of isopropyl group at 9898 ppm (11) δ = 0 A signal of a hydrogen atom bonded to a carbon atom on the methyl group of the isopentyl group was observed at 0.842 ppm. Moreover, in the analysis using ¹³ C-NMR, 174.91, 72.34, 59.88, 5
2.96, 33.59, 32.22, 29.44, 2
Signals were observed at 8.62, 22.57, (18.24, 18.08) and 14.28 ppm, and it was confirmed that this compound was a racemic mixture of D and L integrated.

[0013]

【Example】

(Example 1) Synthesis of ethyl 3-methoxy-2-isopropyl-2-isopentylpropionate (1) Synthesis of ethyl 2-isopentylmalonate A 2 L flask equipped with a stirrer, a Dimroth and a dropping funnel was charged with a nitrogen stream. Below, 300 ml of dry ethanol and 200 ml of sodium ethoxide (Aldrich) were filled. Diethyl malonate 128g (0.8mo
1) was added, and the mixture was stirred at room temperature for 30 minutes. Then, 92 g (0.61 mol) of isopentyl bromide and 50 ml of ethanol were added, and the mixture was heated under reflux while the reaction was monitored by gas chromatography. After the reaction was completed, the reaction mixture was poured into 500 ml of dilute hydrochloric acid. It was extracted with 200 ml of pentane × 3. The organic phase was neutralized with saturated sodium hydrogen carbonate solution, washed with saturated ammonium chloride solution and water and then dried under sodium sulfate. The solvent was distilled off with a rotary evaporator, and the product was dried under reduced pressure to obtain the desired product. bp 127-133 ° C / 11mmHg, yield
116 g (63%), GC> 98.5% ¹ H-NMR (400 MH, CDCl ₃ , TMS) 4.105 (m, 4H), 3.19 (t, 1H), 1.
798 (q, 1H), 1.483 (p, 1H), 1.1
83 (t, 6H), 1.144-1.086 (m, t
2H), 0.798 (d, 6H) ¹³ C-NMR (100 MH, CDCl ₃ ) 169.40, 61.05, 52.09, 36.22,
27.69, 26.56, 22.21, 13.91 pp
m

(2) Synthesis of ethyl 2-isopropyl-2-isopentylmalonate A 2 L flask equipped with a stirrer, Dimroth and dropping funnel was charged with 500 ml of dry ethanol and 250 ml of sodium ethoxide (Aldrich) under a nitrogen stream. Filled. Ethyl 2-isopentyl malonate 69 g
(0.3 mol) was added, and the mixture was stirred at room temperature for 30 minutes. Then, 73 g (0.6 mol) of isopentyl bromide and 50 ml of ethanol were added, and the mixture was heated under reflux for 24 hours while tracking the reaction by gas chromatography. 300 ml of sodium ethoxide (Aldric
h) and isopentyl bromide 80g (0.7mo
1) was added, and the mixture was heated under reflux for 48 hours. After the reaction was completed, the reaction mixture was poured into 500 ml of dilute hydrochloric acid. After extracting with 200 ml of pentane × 3, it was dried under sodium sulfate. The solvent was distilled off with a rotary evaporator, and the product was dried under reduced pressure to obtain the desired product. bp 141-150 ° C / 7mmHg, yield
9.3 g (32%), GC> 98.3% ¹ H-NMR (400 MH, CDCl ₃ , TMS) 4.127 (q, 4H), 2.257 (p, 1H),
1.844-1.802 (m, 2H), 1.438
(P, 1H), 1.999 (t, 6H), 1.049-
0.990 (m, 2H), 0.926 (d, 6H),
0.797 (d, 6H) ¹³ C-NMR (100 MH, CDCl ₃ ) 171.19, 61.489, 60.466, 33.2
62, 31.490, 31.362, 28.366, 2
2.272, 18.482, 14.079 ppm

(3) 2-formyl-2-isopropyl-
Synthesis of ethyl 5-methyl-hexanoate In a 300-ml three-necked flask equipped with a magnetic stirrer and a dropping funnel, 100 ml of dry toluene under a nitrogen stream and ethyl 2-isopropyl-2-isopropenylmalonate 6.
1 g (0.0224 mol) was charged. The contents of the flask were cooled to −78 ° C. and 30 ml of diisobutylaluminum hydride (1.5 M / 1 in toluene).
After e) was added dropwise with stirring over 30 minutes, the mixture was further stirred at the same temperature for 1 hour. 50 ml of methyl alcohol was added to quench unreacted diisobutylaluminum hydride. The reaction mixture was poured into 100 ml of diluted hydrochloric acid. After extracting with 50 ml of pentane × 3, the extract was dried under sodium sulfate. The solvent was distilled off with a rotary evaporator, and the product was dried under reduced pressure to obtain the desired product. bp 129-135 ° C / 22mmHg, yield
5.91 g (-100%), GC> 99% ¹ H-NMR (400 MH, CDCl ₃ , TMS) 10.16 (s, 1 H), 4.331 (q, 2 H),
2.323 (m, 1H), 1.971-1.699
(M, 1H), 1.676-1.580 (m, 1H),
1.563-1.514 (m, 1H), 1.355
(T, 3H), 1.62 (d, 2H), 0.0084-
0.915 (m, 12H) ¹³ C-NMR (100 MH, CDCl ₃ ) 202.094, 172.405, 63.718, 6
0.786, (33.518, 33.244), 28.
493, 28.293, (22.355, 22.17)
2), 18.427, 17.495, 14.170 pp
m

(4) Synthesis of ethyl 3-hydroxy-2-isopropyl-2-isopentylpropionate In a 300 ml three-necked flask equipped with a magnetic stirrer and a dropping funnel, 100 ml of dry ethanol and 0.85 g of sodium boron hydride under a nitrogen stream. (0.0224m
ol). 2-formyl-2-isopropyl-
6.1 g of ethyl 5-methyl-hexanoate (0.0224
(mol) was added dropwise with stirring over 30 minutes at room temperature.
Then, the flask contents were heated to reflux while tracking the reaction by gas chromatography. After the reaction was completed, the contents of the flask were poured into 100 ml of diluted hydrochloric acid. 50 ml of pentane
After extracting with × 3, it was dried under sodium sulfate. The solvent was distilled off with a rotary evaporator, and the product was dried under reduced pressure to obtain the desired product. bp 125-133 ° C / 7mmHg, m / z = 23
1, yield 6.5 g (59%), GC> 98% ¹ H-NMR (400 MH, CDCl ₃ , TMS) 4.125 (d, 2H), 3.660 (q, 2H),
2.505 (s, 1H), 1.981 (p, 1H),
1.620-1.555 (m, 1H), 1.499-
1.377 (m, 2H), 1.227 (t, 3H),
1.160-1.114 (m, 1H), 0.985-
0.970 (m, 1H), 0.885 (dd, 6)
H), 0.826 (d, 6H) ¹³ C-NMR (100 MH, CDCl ₃ ) 176.94, 63.81, 60.19, 53.27,
33.50, 32.09, 30.0, 28.69, (2
2.48, 22.37), (18.57, 17.3).
1), 14.17 ppm

(5) 3-methoxy-2-isopropyl-
Synthesis of ethyl 2-isopentylpropionate In a 500 ml three-necked flask equipped with a magnetic stirrer and a dropping funnel, 200 ml of dioxane and 2.75 g (0.0224 mol) of potassium tertiary butoxide under a nitrogen stream.
And ethyl 3-hydroxy-2-isopropyl-2-isopentylpropionate (5.91 g, 0.0224 mo)
l) was charged. Stir methyl iodide at room temperature for 3
It was added dropwise over 0 minutes. Then, the flask contents were heated to reflux while tracking the reaction by gas chromatography.
After the reaction was completed, the contents of the flask were poured into 100 ml of diluted hydrochloric acid. After extracting with 50 ml of pentane × 3, the extract was dried under sodium sulfate. The solvent was distilled off with a rotary evaporator, and the product was dried under reduced pressure to obtain the desired product. bp 126.5-127 ° C./13 mmHg, m / z =
244, yield 1.3 g (59%), GC> 99% ¹ H-NMR (400 MH, CDCl ₃ , TMS) 4.096 (q, 2H), 3.472 (s, 2H),
3.273 (s, 3H), 1.948 (h, 1H),
1.663-1.570 (m, 2H), 1.446
(H, 1H), 1.214 (t, 3H), 1.149-
1.087 (m, 1H), 0.962-0.927
(M, 1H), 0.898 (m, 6H), 0.842
(D, 6H) ¹³ C-NMR (100 MH, CDCl ₃ ) 174.91, 72.34, 59.88, 52.96,
33.59, 32.22, 29.44, 28.62, 2
2.57, (18.24, 18.08), 14.28p
pm

(Comparative Example 1) In a 500 ml three-necked flask equipped with a magnetic stirrer, a dropping funnel and a Dimroth under a nitrogen stream, 21 g (0.21 mo of diisopropylamine) was added.
1) and 60 ml of dehydrated tetrahydrofuran were charged, and the contents were cooled with ice. 132 ml of n-butyllithium (0.
21 mol) (1.7 mol / L hexane solution)
It dripped over minutes. After completion of dropping, the reaction solution was heated to 30 ° C. and stirred for 30 minutes. Then, the content of the flask is -78.
Cooled to ° C. Separately synthesized 20 g (0.20 mol) of ethyl 2-isopropyl-2-isopentyl acetate and 30 ml of dehydrated tetrahydrofuran were added dropwise over 30 minutes, followed by stirring for 30 minutes. Then, 21 g (0.265 mol) of chloromethyl methyl ether and 30 ml of dehydrated tetrahydrofuran were added dropwise over 15 minutes. The contents of the flask were sampled and analyzed by gas chromatography, but the desired product was not obtained.

[Reference Examples and Reference Comparative Examples] In the reference examples and the reference comparative examples, the meter flow rate (abbreviated as MFR) is JIS K-7210-1976: Table 1. Test condition 14 (test temperature 230 ° C., test load 2.16 kg
It was measured according to f). Heptane index (H.
R. Abbreviated. ) Represents the remaining amount in% after the obtained polymer was extracted with boiling n-heptane for 6 hours. In Reference Examples and Reference Comparative Examples, each raw material (organic solvent, olefin,
Hydrogen, titanium compounds, magnesium compounds, etc.) are all substantially free of water. The production and polymerization of the solid catalyst component were carried out in the presence of substantially no water and in an inert atmosphere such as nitrogen.

(Preparation of solid catalyst component 1) 20 g (0.21 mol) of anhydrous magnesium chloride (obtained by calcining and drying commercially available anhydrous magnesium chloride in a dry hydrogen chloride gas stream at about 500 ° C. for 15 hours) ,
2. Ethyl 3-methoxy-2-propyl-2-isopentylpropionate 12.2 g (0.05 mol), titanium trichloride 1.5 g and silicon oil as a grinding aid (TSS-451, 20 cs manufactured by Shin-Etsu Chemical Co., Ltd.) 3. Under a dry nitrogen flow, 0 mol was placed in a container for a vibrating ball mill (stainless steel cylindrical type, circular volume 1 L, porcelain balls having a diameter of 10 mm and apparent volume of about 50% filled). This was attached to a vibrating ball mill with an amplitude of 6 mm and co-pulverized for 15 hours to obtain a co-pulverized solid material. 15 g of the obtained co-ground product was suspended in 150 m of 1,2-dichloroethane and stirred at 80 ° C. for 2 hours, and then a solid part was collected by filtration and washed with hexane to give 1,2-dichloroethane free in the washing solution. Washed thoroughly until no more was detected. This was dried under reduced pressure at 30 ° C to 40 ° C and hexane was removed to obtain a solid catalyst component. When the obtained solid catalyst component was analyzed, the content of titanium atoms in this solid catalyst component was 2.4% by weight.

(Physical properties of polymerized and produced polymer) Internal volume 3 L
Into a stainless steel autoclave, 17 mg of the solid catalyst component prepared above and diethylaluminum chloride were placed, and then 760 g of propylene and 0.1
After charging g of hydrogen, the temperature of the autoclave was raised and the internal temperature was kept at 70 ° C. After 1 hour, the unreacted gas was released to collect the polymerization. The polymerization results are shown in Table 1.

[Comparative Example] As an electron-donating compound, 3-
Instead of ethyl methoxy-2-isopropyl-2-isopentylpropionate, 13.9 g of dibutyl phthalate
A solid catalyst component was prepared in the same manner as in Example 1 except that (0.05 mol) was used, and the polymerization was evaluated under the same conditions. The results are shown in Table 1.

[0023]

[Table 1]

[0024]

The present invention has an ester group and an alkoxy group in the molecule, and has two alkyl substituents, especially bulky substituents, on the carbon atom at the α-position counted from the ester group. It has become possible to provide a novel ester compound effective as an electron donating compound.

[Brief description of drawings]

FIG. 1 ¹ H- of ethyl 3-methoxy-2-isopropyl-2-isopentylpropionate prepared in Example 1.
NMR chart.

[Figure 2] of 3-methoxy-2-isopropyl-2-isopentyl propionate prepared in Example 1 ¹³ C-
NMR chart.

FIG. 3 is the GC-value of ethyl 3-methoxy-2-isopropyl-2-isopentylpropionate prepared in Example 1.
MS chart.

Claims (5)

[Claims] 1. A compound represented by the general formula (1): (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
3-methoxy-2-isopropyl-2-isopentylpropionic acid alkyl ester represented by: 2. 3-hydroxy-2-isopropyl-2
Of 3-methoxy-2-isopropyl-2-isopentylpropionic acid alkyl ester, characterized in that isopentylpropionic acid alkyl ester is reacted with methyl halide or methyl paratoluenesulfonate in the presence of a dehalogenating agent. Production method. 3. 3-methoxy-2-isopropyl-2-
A method for producing an alkyl ester of 3-methoxy-2-isopropyl-2-isopentylpropionic acid, which comprises reacting an isopentylpropionic acid compound with an alcohol. 4. A general formula (2): (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
2-formyl-2-isopropyl-5-methyl-hexanoic acid alkyl ester represented by 5. A compound represented by the general formula (3): (In the formula, R represents a lower alkyl group having 1 to 4 carbon atoms.)
3-hydroxy-2-isopropyl-2-isopentylpropionic acid alkyl ester represented by: