JP2000256222A - Production of alkyl-substituted cyclopentadiene compounds - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the endo isomer of an alkyl-substituted cyclopentadiene compound in a high yield by adding an acidic slurrying agent-containing aqueous solution to the reaction mixture of an alkylcyclopentenone compound with an alkyl Grignard reagent and adding an acid catalyst to the obtained slurry liquid to remove the water. SOLUTION: This method for producing an alkyl-substituted cyclopentadiene compound of formula IV (for example, 1-methyl-3-butylcyclopentane-1,3-diene) comprises subjecting (A) a compound of formula I [R1 is a 1-4C alkyl; (m) is 1-3] (for example, 3-methyl-2-cyclopentenone) and (B) a compound of the formula: R2CH2MgX (R2 is a 1-7C alkyl; X is a halogen) (for example, ethyl magnesium chloride) to an alkylation reaction, mixing the obtained reaction mixture containing the compound of formula II with (C) an acidic slurrying agent (for example, orthphosphoric acid)-containing aqueous solution to form a slurry liquid, and then adding an acid catalyst (for example, hydrochloric acid) to the slurry liquid to remove the OH group from the compound of formula III in the slurry liquid, thus obtaining the compound of formula III.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing an alkyl-substituted cyclopentadiene.

[0002]

BACKGROUND OF THE INVENTION Alkyl-substituted cyclopentadienes are used as monomers and are widely used in the production of metallocene compounds of transition metals such as titanium, zirconium and hafnium. This metallocene compound is
It is widely used as an effective component of olefin polymerization catalysts.

[0003] Conventional production methods, for example, using 3-methylcyclopentenone and 3-n-propylmagnesium chloride
In the case of producing 1-methyl-3-n-propyl-1,3-cyclopentadiene, 1-methyl-3-n-propylidenecyclopentene (exo form) may be used in addition to the intended cyclopentadiene endo form. By-products are observed. Metallocene compounds are produced from endo-forms, but not from exo-forms. Therefore, a method for producing an alkyl-substituted cyclopentadiene having a small amount of an exo-form by-product is desired.

[0004] Conventionally, for example, in producing a 1,3-dialkylcyclopentadiene as an endo-form from a 3-alkylcyclopentenone by a Grignard reaction, the following synthesis route is followed by the production of a Grignard reaction mixture (after alkylation). The post-treatment method is difficult, and under neutral or basic conditions, solids precipitate on the way and cannot be stirred, and dehydration from 1,3-dialkylcyclopentan-2-en-1-ol (OH form) Does not occur, and under strong acidic conditions of pH 1 or less, isomerization of an end product, an end product, to an exo product of a by-product occurs to obtain 1,3-dialkylcyclopentadiene, an endo product, in high yield. I couldn't do that.

[0005]

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In the above formula, R ¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, and R ² is a linear or branched alkyl group having 1 to 7 carbon atoms. .

As a method for increasing the yield of the desired endo-substituted alkyl-substituted cyclopentadiene, Japanese Patent Application Laid-Open No.
No. 188069, which is obtained by reacting cyclopentenone with a Grignard reagent and then dehydrating the resulting tertiary alcohol intermediate by acidification using an organic carboxylic acid such as acetic acid. Production of alkylcyclopentadienes comprising producing an alkyl-substituted cyclopentadiene product wherein the ratio of nuclear isomers (corresponding to endo-isomers) to extranuclear isomers (corresponding to exo-isomers) is at least 1.5 / 1 A method has been proposed.

However, in this method, there are problems such as precipitation of solids on the way, an increase in steps for removing the organic carboxylic acid, and difficulty in completely removing the organic carboxylic acid. When the organic carboxylic acid remains, the intended alkyl-substituted cyclopentadiene has poor storage stability and tends to be changed to a compound having a high boiling point.

Japanese Patent Application Laid-Open No. 8-319245 discloses that an exo form of a polyalkyl-substituted cyclopentadiene is converted to an inorganic acid such as HCl, BF ₃ or H ₂ SO ₄ or a relatively strong acid such as formic acid or methanesulfonic acid. There has been proposed a method of converting an endo-form by contact with an organic acid. However, as in the examples described in this publication, in this method, the polyalkyl-substituted cyclopentadiene after conversion of the exo form into the endo form has an abundance ratio between the endo form and the exo form (endo form / exo form). Is low.

The present inventors have conducted intensive studies in order to solve the above-mentioned problems, and prepared a reaction mixture of a 3-alkylcyclopentenone and an alkyl Grignard reagent with a dibasic acid salt of phosphoric acid (eg, NaH _2). By dropping the solution into an aqueous solution of PO ₄ ), an exothermic reaction proceeds at pH _{4 to} 7 and a slurry liquid (1,3-dialkylcyclopentan-2-en-1-ol (OH form) free of deposition of massive solids And the addition of a strong acid such as hydrochloric acid or sulfuric acid to the slurry to adjust the pH of the slurry to pH 1. As a result, the endothermic reaction proceeds promptly, and the OH form is dehydrated. Has been eliminated, and it has been found that 1,3-dialkylcyclopentadienes as endo-forms can be obtained in high yield, and the present invention has been completed.

[0011]

SUMMARY OF THE INVENTION The object of the present invention is to solve the problems associated with the prior art as described above, without depositing a solid substance which makes stirring difficult, and having an alkyl-substituted cyclopentadiene compound in an endo form. It is an object of the present invention to provide a method for producing a compound in a high yield.

[0012]

SUMMARY OF THE INVENTION The process for producing an alkyl-substituted cyclopentadiene according to the present invention is a process for producing an alkyl-substituted cyclopentadiene from an alkylcyclopentenone and an alkyl Grignard reagent.

[0013]

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Wherein R ¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3;
The following general formula [II] R ² CH ₂ MgX ... [II] [wherein, R ² is a linear or branched alkyl group having 1 to 7 carbon atoms, and X is a halogen atom. A reaction mixture with an alkyl Grignard reagent represented by
It is characterized by mixing with an aqueous solution containing an acidic slurrying agent to form a slurry liquid, and then adding an acid catalyst to the slurry liquid for dehydration.

As the acidic slurry agent, a phosphoric acid compound or a mixture of two or more phosphoric acid compounds is used.

As the acid catalyst, a strongly acidic inorganic acid having a dehydrating action or an organic acid having a dehydrating action is used.

According to the present invention, the weight ratio of endo-form to exo-form (endo-form / exo-form) is 70 / 30-85.
/ 15 alkyl-substituted cyclopentadienes can be obtained.

[0018]

DETAILED DESCRIPTION OF THE INVENTION Hereinafter, a method for producing an alkyl-substituted cyclopentadiene according to the present invention will be specifically described.

In the method for producing an alkyl-substituted cyclopentadiene according to the present invention, first, a reaction mixture of a specific alkylcyclopentenone and a specific alkyl Grignard reagent is prepared.

Alkylcyclopentenone The alkylcyclopentenone used in the present invention is represented by the following general formula [I].

[0021]

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In the general formula [I], R ¹ is a linear or branched alkyl group having 1 to 4 carbon atoms.
Is an integer of 1 to 3.

Specific examples of the linear alkyl group having 1 to 4 carbon atoms for R ¹ include a methyl group, an ethyl group, an n-propyl group and an n-butyl group. 1 to
Specific examples of the branched alkyl group 4 include an isopropyl group, an isobutyl group, an s-butyl group, and a t-butyl group.

As the alkylcyclopentenone represented by the above general formula [I], specifically, 3-methyl-2-
Cyclopentenone, 3-ethyl-2-cyclopentenone, 3-
n-propyl-2-cyclopentenone, 3-n-butyl-2-cyclopentenone, 3-isopropyl-2-cyclopentenone,
Monoalkylcyclopentenones such as 3-isobutyl-2-cyclopentenone, 3-s-butyl-2-cyclopentenone and 3-t-butyl-2-cyclopentenone; 3,4-dimethyl-2- Cyclopentenone, 3-methyl-4-ethyl-2-cyclopentenone, 3-methyl-4-isopropyl-2
-Cyclopentenone, 3-methyl-4-t-butyl-2-cyclopentenone, 3,4-diethyl-2-cyclopentenone, 3-ethyl-4-isopropyl-2-cyclopentenone, 3,4 -Diisopropyl-2-cyclopentenone, 3,4-di-t-butyl-2
-Dialkylcyclopentenones such as cyclopentenone; 3,4,5-trimethyl-2-cyclopentenone, 3,4-dimethyl
-5-Ethyl-2-cyclopentenone, 3,4-dimethyl-5-isopropyl-2-cyclopentenone, 3,4-dimethyl-5-t-
Butyl-2-cyclopentenone, 3,5-dimethyl-4-isopropyl-2-cyclopentenone, 3,5-dimethyl-4-t-butyl-2-cyclopentenone, 2,5-dimethyl-3- Ethyl-2-
And trialkylcyclopentenones such as cyclopentenone.

Alkyl Grignard Reagent The alkyl Grignard reagent used in the present invention is represented by the following general formula [II].

R ² CH ₂ MgX ... [II] In the general formula [II], R ² is a linear or branched alkyl group having 1 to 7 carbon atoms, and X is a halogen atom. .

Specific examples of the linear alkyl group having 1 to 7 carbon atoms for R ² include methyl, ethyl, n-propyl, n-butyl, n-pentyl, n-hexyl, Examples of the branched alkyl group having 1 to 7 carbon atoms include isopropyl, isobutyl, s-butyl, t-butyl, isopentyl, and t-heptyl.
Examples include a pentyl group, a neopentyl group, an isohexyl group, and an isoheptyl group.

As the halogen atom for X, specifically,
Examples include atoms such as fluorine, chlorine, bromine, and iodine.

Specific examples of the alkyl Grignard reagent represented by the above general formula [II] include ethyl magnesium chloride, propyl magnesium chloride, butyl magnesium chloride, pentyl magnesium chloride, hexyl magnesium chloride, heptyl magnesium chloride, octyl magnesium chloride. And the like.

Alkylcyclopentenones and alkyl groups
Reaction mixture with Lignard reagent The reaction mixture of alkylcyclopentenones and alkyl Grignard reagents used in the present invention is obtained by subjecting the above alkyl Grignard reagent and alkyl cyclopentenones to an alkylation reaction under the following conditions. can get.

The above reaction conditions are as follows: the molar ratio of alkyl Grignard reagent to alkyl cyclopentenone [alkyl Grignard reagent / alkyl cyclopentenone] is 1.0 to 1.2, and the reaction temperature is -20 ° C. 30 ° C,
The reaction temperature is preferably 0 to 25 ° C, and the reaction time varies depending on the reaction scale, but is usually 0.5 to 8 hours, preferably 1 to 8 hours.
~ 3 hours.

In the present invention, an inert solvent such as an ether solvent is preferably used as a solvent for the above-mentioned alkylcyclopentenones and a solvent for the above-mentioned alkyl Grignard reagent. Specific examples of such ether solvents include diethyl ether, tetrahydrofuran (THF), 1,4-dioxane, 1,3-dioxolan,
2-dimethoxyethane, 2-methyltetrahydrofuran and the like.

The ether solvents described above can be used alone or in combination of two or more.
Further, a mixed solvent obtained by adding an aromatic hydrocarbon such as toluene to the above ether-based solvent can also be used.

When the above-mentioned solvent is added to the alkylcyclopentenone, the solvent is usually used in an amount of 0.90 to 1.20 per 100 parts by weight of the alkylcyclopentenone.
Parts by weight, preferably 1.00 to 1.10 parts by weight.

When the above-mentioned solvent is added to the alkyl Grignard reagent, the solvent is usually used in an amount of 2 to 10 parts by weight based on 100 parts by weight of the alkyl Grignard reagent.
Preferably, it is used in a proportion of 3 to 5 parts by weight.

The reaction mixture obtained as described above is
A polyalkylcyclopentan-2-ene-1-oxymagnesium chloride represented by the following general formula [III],
The concentration is usually desirably in the range of 0.8 to 2.5 mol / kg.

[0037]

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R ¹ and m in the general formula [III] are the same as in the general formula [I], and R ² is the same as in the general formula [II].

Next, the reaction mixture (Grignard reaction mixture) of the alkylcyclopentenone and the alkyl Grignard reagent obtained as described above is mixed with an aqueous solution containing an acidic slurry agent to form a slurry liquid.

Acidic Slurrying Agent-Containing Aqueous Solution As the acidic slurrying agent constituting the acidic slurrying agent-containing aqueous solution used in the present invention, a phosphoric acid compound or a mixture of two or more phosphoric acid compounds is used.
As such a phosphate compound, specifically, sodium dihydrogen phosphate (NaH ₂ PO ₄ ), orthophosphoric acid (H
₃ PO ₄ ), potassium dihydrogen phosphate, lithium dihydrogen phosphate and the like.

The aqueous solution containing an acidic slurrying agent used in the present invention has an acidic slurrying agent concentration of 1 to 5 mol / kg,
Preferably it is 1.5 to 2.5 mol / kg.

The aqueous solution containing the acidic slurrying agent having the above concentration has a molar ratio of the acidic slurrying agent to the alkyl Grignard reagent [acidic slurrying agent / alkyl Grignard reagent] of 1 to 1.2, preferably 1.02 to 1 It is used in such an amount as to fall within the range of .10.

The reaction mixture of the above alkylcyclopentenones and the alkyl Grignard reagent and the above aqueous solution containing a slurrying agent are mixed and acidified to obtain a slurry liquid. This slurry liquid stably contains polyalkylcyclopentan-2-en-1-ol (OH form) represented by the following general formula [IV].

[0044]

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R ¹ and m in the general formula [IV] are the same as in the general formula [I], and R ² is the same as in the general formula [II].

Next, an acid catalyst is added to the slurry liquid obtained as described above and dehydrated, and a hydroxyl group is eliminated from polyalkylcyclopentan-2-en-1-ol (OH form) in the slurry liquid. Let it. When an acid catalyst is added to the slurry, the slurry becomes a two-layer solution consisting of an organic layer and an aqueous layer.

Acid Catalyst The acid catalyst used in the present invention is a strongly acidic inorganic acid having a dehydrating action, or a relatively acidic organic acid having a dehydrating action.

Specific examples of such a strongly acidic inorganic acid include hydrochloric acid, sulfuric acid, boric acid trifluoride (HBF ₄ ), hydrofluoric acid, and sulfurous acid.

In addition, as the organic acid, specifically,
Formic acid, methanesulfonic acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and the like can be mentioned.

Among these acid catalysts, aqueous solutions such as hydrochloric acid and sulfuric acid are preferably used.

The acid catalyst as described above is used in such an amount that the molar ratio of the acid catalyst to the alkyl Grignard reagent [acid catalyst / alkyl Grignard reagent] is in the range of 1.0 to 1.2. The molar ratio of the acid catalyst to the alkyl Grignard reagent [acid catalyst / alkyl Grignard reagent] is 1.0
When the acid catalyst is used in such an amount that the amount becomes less than the above, the pH of the slurry becomes basic, and the polyalkylcyclopentan-2-en-1-ol (OH form) in the slurry becomes less likely to be dehydrated. In addition, the yield of the target, endo-substituted alkyl-substituted cyclopentadiene tends to decrease. On the other hand, when the acid catalyst is used in an amount such that the molar ratio of the acid catalyst to the alkyl Grignard reagent [acid catalyst / alkyl Grignard reagent] exceeds 1.2, the pH of the slurry liquid is reduced.
Is strongly acidic, so that the isomerization of the endo-substituted alkyl-substituted cyclopentadiene to the exo-form tends to occur, and the yield of the target endo-substituted alkyl-substituted cyclopentadiene tends to decrease.

The temperature of the acid catalyst added to the slurry liquid is usually 5 to 30 ° C., preferably 15 to 25 ° C. The addition of the acid catalyst to the slurry liquid is usually 0.5 to 3 hours, preferably 1 to 3 hours. Performed for ~ 2 hours.

By adding an acid catalyst to the above slurry liquid as described above, OH groups are eliminated from polyalkylcyclopentan-2-en-1-ol (OH form) in the slurry liquid, and An endo-substituted alkyl-substituted cyclopentadiene can be obtained in high yield.

The alkyl-substituted cyclopentadiene in the endo form is represented by the following general formula [V].

[0055]

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R ¹ and m in the general formula [V] are the same as in the general formula [I], and R ² is the same as in the general formula [II].

Examples of the alkyl-substituted cyclopentadiene represented by the general formula [V] include, for example, 1-methyl
-3-butylcyclopentane-1,3-diene, 1-ethyl-3-
Butylcyclopentane-1,3-diene, 1-propyl-3-butylcyclopentane-1,3-diene, 1,5-dimethyl-3-butylcyclopentane-1,3-diene, 1-methyl-3- Butyl
-5-ethylcyclopentane-1,3-diene, 1,4,5-trimethyl-3-butylcyclopentane-1,3-diene and the like.

The exo form is represented by the following general formula [VI]
Is represented by

[0059]

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R ¹ and m in the general formula [VI] are the same as in the general formula [I], and R ² is the same as in the general formula [II].

Purification of Alkyl-Substituted Cyclopentadienes When an acid catalyst is added to the slurry as described above, a two-layer solution comprising an organic layer containing the target alkyl-substituted cyclopentadiene as an end product and an aqueous layer is obtained. Become.

In the present invention, the alkyl-substituted cyclopentadiene is purified by washing the organic layer obtained by separating this solution with a detergent, for example, saturated aqueous sodium bicarbonate and water.

The alkyl-substituted cyclopentadiene purified as described above has a weight ratio of endo-form to exo-form [endo-form / exo-form] of usually 70/30 to 85.
/ 15.

[0064]

According to the present invention, in the post-treatment of Grignard reaction (acidification / dehydration step with an acid), the target compound can be produced without a sudden heat generation or precipitation of a solid which makes stirring difficult. An endo-substituted alkyl-substituted cyclopentadiene can be obtained in high yield.

[0065]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to these examples.

[0066]

Example 1 65.0 g of a 23.7% strength butylmagnesium chloride solution in toluene-THF (C ₄ H ₉ MgC
1: 0.132 mol, toluene / THF (weight ratio): 2
/ 5) to 9.6 g of 3-methylcyclopentenone (0.1
(25 mol) in toluene (21.2 g) was added dropwise at 30 ° C. or lower while stirring. After the dropwise addition, the mixture was stirred at 25 ° C. for 1 hour to obtain a tan transparent solution as a Grignard reaction mixture.

The temperature of the above reaction mixture was lowered to 20 ° C. or lower.
0 mol / kg aqueous solution of sodium dihydrogen phosphate 6
The solution was added dropwise to 9.2 g over 2 hours. The pH of the reaction mixture at the start of the dropwise addition of the aqueous solution of sodium dihydrogen phosphate was 4, and the pH at the end of the dropwise addition was 7. During this dropping, insolubles were gradually generated, and at the end of the dropping, a slurry liquid containing the insolubles was obtained. Stirring of this slurry liquid was continued for 5 hours, but no insoluble matter was found to adhere to the stirring blades or reactor walls.

As a result of analyzing the organic layer obtained by allowing the slurry to stand and separating the mixture by gas chromatography, the main product was
It was 1-butyl-3-methylcyclopentan-2-en-1-ol.

A pH of 3.7 was added to the slurry by adding a 3.7 mol / kg aqueous hydrochloric acid solution. By the addition of the hydrochloric acid aqueous solution, the insolubles in the slurry liquid were dissolved, and a two-layer solution consisting of an organic layer and an aqueous layer was formed.

After separating the organic layer, it was washed with saturated aqueous sodium hydrogen carbonate and water to obtain 72.4 g of a solution. The main product in this solution is 1-methyl-3-butylcyclopentane-1,3-
It was a diene (endo form) and the by-product was 1-methyl-3-butylidenecyclopentene (exo form). The weight ratio of the endo-form to the exo-form (endo-form / exo-form) determined by gas chromatography was 80/20.

[0071]

Example 2 A yellow-brown transparent Grignard reaction mixture obtained in the same manner as in Example 1 was cooled to 20 ° C. or lower, and 69.2 g of a 2.0 mol / kg sodium dihydrogen phosphate aqueous solution was prepared.
For 2 hours. The pH of the reaction solution at the start of the dropping of the aqueous solution of sodium dihydrogen phosphate is 4, and the pH of the reaction solution is 7 at the end of the dropping.
Met. During this dropping, an insoluble matter was gradually generated in the reaction solution, and a slurry liquid containing the insoluble matter was obtained at the end of the dropping. Stirring of this slurry liquid was continued for 5 hours, but no insoluble matter was found to adhere to the stirring blades or reactor walls.

A 2.2 mol / kg aqueous solution of sulfuric acid was added to the slurry to adjust the pH to 2. By the addition of the sulfuric acid aqueous solution, the insolubles in the slurry liquid were dissolved to form a two-layer solution including an organic layer and an aqueous layer.

After separating the organic layer, it was washed with saturated aqueous sodium hydrogen carbonate and water to obtain 69.4 g of a solution. The main product in this solution is 1-methyl-3-butylcyclopentane-1,3-
It was a diene (endo form) and the by-product was 1-methyl-3-butylidenecyclopentene (exo form). As a result of analyzing the weight ratio of the endo-form to the exo-form in this solution by gas chromatography, the weight ratio of the endo-form to the exo-form (endo-form / exo-form) was 83/17.

[0074]

Example 3 A yellow-brown transparent Grignard reaction mixture obtained in the same manner as in Example 1 was cooled to 20 ° C. or less, and 69.2 g of a 2.0 mol / kg aqueous sodium dihydrogen phosphate solution was prepared.
For 5 hours. The pH of the reaction solution at the start of the dropping of the aqueous solution of sodium dihydrogen phosphate is 4, and the pH of the reaction solution is 7 at the end of the dropping.
Met. During this dropping, insolubles were gradually generated, and at the end of the dropping, a slurry liquid containing the insolubles was obtained. Stirring of this slurry liquid was continued for 5 hours, but no insoluble matter was found to adhere to the stirring blades or reactor walls.

A 2.2 mol / kg aqueous solution of sulfuric acid was added to the slurry to adjust the pH to 2. By the addition of the sulfuric acid aqueous solution, the insolubles in the slurry liquid were dissolved to form a two-layer solution including an organic layer and an aqueous layer.

After separating the organic layer, it was washed with saturated aqueous sodium hydrogen carbonate and water to obtain 70.5 g of a solution. The main product in this solution is 1-methyl-3-butylcyclopentane-1,3-
It was a diene (endo form) and the by-product was 1-methyl-3-butylidenecyclopentene (exo form). As a result of analyzing the weight ratio of the endo-form to the exo-form in this solution by gas chromatography, the weight ratio of the endo-form to the exo-form (endo-form / exo-form) was 83/17.

[0077]

Comparative Example 1 A yellow-brown, transparent Grignard reaction mixture obtained in the same manner as in Example 1 was heated to 25 ° C. and added dropwise to 67 g of a 21% strength aqueous ammonium chloride solution. The pH of the reaction solution at the start of the dropping of the aqueous ammonium chloride solution was 6, and the pH at the end of the dropping was 10. During this dropping, insolubles were gradually generated in the reaction solution, and at the end of the dropping, the whole reaction mixture became creamy, and torque was applied to the stirring blades, making stirring impossible. In addition, the deposits were aggregated and adhered to the stirring blades and the reactor wall.

To a mixture of the above Grignard reaction mixture and an aqueous ammonium chloride solution, 37.6 g of a 3.7 mol / kg aqueous hydrochloric acid solution (HCl: 0.139 mol) was added dropwise. At the end of the dropping, a lump deposit remained, and the pH of the mixed solution was 0.5 to 1. However, after stirring for 30 minutes, the lump precipitate was dissolved, and the mixture was composed of an organic layer and an aqueous layer having a pH of 2. A layer solution was obtained.

After separating the organic layer, it was washed with saturated aqueous sodium hydrogen carbonate and water to obtain 70.4 g of a solution. As a result of analyzing the weight ratio of the endo-form to the exo-form in this solution by gas chromatography, the weight ratio of the endo-form to the exo-form (endo-form / exo-form) was 55/45.

[0080]

Comparative Example 2 A yellowish brown transparent Grignard reaction mixture obtained in the same manner as in Example 1 was added to a 25% acetic acid aqueous solution (pH 2).
63.4 g was added dropwise at 2O <0> C or less for 2 hours. A high-viscosity insoluble material was precipitated after the dropping of the acetic acid aqueous solution, adhered to the stirring blades and the walls of the reactor, and a torque was applied to the stirring. When about 40 g of the acetic acid aqueous solution was added, a decrease in the insoluble matter was observed, and the insoluble matter disappeared when the dropwise addition was completed.

After completion of the dropping, the temperature was raised to 40 ° C. and the mixture was stirred for 2 hours to obtain a solution in which an aqueous layer and an organic layer were mixed. At this time, the pH of the aqueous layer was 3.9.

The organic layer was separated from the two-layer solution comprising the organic layer and the aqueous layer obtained as described above, and washed with a 19% aqueous sodium carbonate solution and water to obtain 41.9 g of a solution. . As a result of analyzing the weight ratio of the endo-form to the exo-form in this solution by gas chromatography, the weight ratio of the endo-form to the exo-form (endo-form / exo-form) was found to be 83 /
It was 17. About 0.2% of acetic acid was present in this solution, and the odor of acetic acid was smelled.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) // C07B 61/00 300 C07B 61/00 300 (72) Inventor Yoichiro Isoda 2 Osaiga, Wakayama, Wakayama No.5-115 F-term in Honshu Chemical Industry Co., Ltd. Research Laboratory 4H006 AA02 AC22 AC24 BA02 BA35 BA36 BA37 BA52 BA66 BC10 BC19 BE01 BE03 BE56 BJ20 FC22 FC76 4H039 CA19 CA29 CF30 CG10

Claims (4)

[Claims] In producing an alkyl-substituted cyclopentadiene from an alkylcyclopentenone and an alkyl Grignard reagent, the following general formula [I]: [Wherein, R ¹ is a linear or branched alkyl group having 1 to 4 carbon atoms, and m is an integer of 1 to 3], and an alkylcyclopentenone represented by the following general formula: [II] R ² CH ₂ MgX [II] wherein R ² is a linear or branched alkyl group having 1 to 7 carbon atoms, and X is a halogen atom. A method for producing an alkyl-substituted cyclopentadiene, comprising: mixing a reaction mixture with an alkyl Grignard reagent to be used with an aqueous solution containing an acidic slurrying agent to form a slurry, and then adding an acid catalyst to the slurry to dehydrate the slurry. . 2. The method according to claim 1, wherein the acidic slurry agent is a phosphoric acid compound,
2. The method for producing an alkyl-substituted cyclopentadiene according to claim 1, wherein the mixture is a mixture of two or more phosphoric acid compounds. 3. The method for producing alkyl-substituted cyclopentadienes according to claim 1, wherein the acid catalyst is a strong acidic inorganic acid having a dehydrating action or an organic acid having a dehydrating action. 4. The alkyl-substituted cyclopentadiene according to claim 1, wherein the weight ratio of endo-form to exo-form (endo-form / exo-form) is in the range of 70/30 to 85/15. The method for producing an alkyl-substituted cyclopentadiene according to any one of the above.