JP2015137232A - METHOD FOR PRODUCING NORBORNANE-2-SPIRO-α-CYCLOALKANONE-α'-SPIRO-2''-NORBORNANE-5,5'',6,6''-TETRACARBOXYLIC ACID AND ESTERS THEREOF - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a norbornane-2-spiro-α-cycloalkanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid and esters thereof, which enables obtaining a norbornane-2-spiro-α-cycloalkanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid and esters thereof with a content of by-products reduced at a higher level.SOLUTION: Provided is a method for producing a norbornane-2-spiro-α-cycloalkanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid and esters thereof, comprising steps of: obtaining a reaction mixture containing a specific norbornane-2-spiro-α-cycloalkanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid and esters thereof by reacting a specific norbornane with an alcohol and carbon monoxide by supplying the carbon monoxide into a mixture containing the specific norbornane, the alcohol, a palladium catalyst, and an oxidant; and purifying the reaction mixture after replacing the alcohol in the reaction mixture with an aromatic hydrocarbon having 6 to 9 carbon atoms to obtain the norbornane-2-spiro-α-cycloalkanone-α'-spiro-2''-norbornane-5,5'',6,6''-tetracarboxylic acid and esters thereof.

Description

  The present invention relates to a process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof. .

  In general, tetracarboxylic dianhydrides are useful as raw materials for producing polyimide resins, epoxy curing agents, and the like. Among such tetracarboxylic dianhydrides, for example, as a raw material for polyimide resins used in the field of electronic equipment, aromatic tetracarboxylic dianhydrides such as pyromellitic dianhydride are mainly used. Has been used. However, such an aromatic tetracarboxylic dianhydride is derived from the aromatic nature, and the resulting polyimide resin is colored, so that it is a raw material for polymimide resins used in applications such as the optical field. Was not enough. Moreover, the polyimide resin obtained by using such an aromatic tetracarboxylic dianhydride has low solubility in a solvent and is not sufficient in terms of workability. Therefore, various aliphatic tetracarboxylic dianhydrides have been studied in order to produce polyimide resins having high light transmittance and excellent solubility in solvents. Under such circumstances, various tetracarboxylic acids and esters thereof have been developed as raw material compounds for producing such aliphatic tetracarboxylic dianhydrides.

  Examples of such a tetracarboxylic acid compound and its esters for producing an aliphatic tetracarboxylic dianhydride and a production method thereof include, for example, a specific general formula in International Publication No. 2011/099518 (Patent Document 1). Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof, and A manufacturing method is disclosed. And the manufacturing method of such tetracarboxylic-acid compound and its ester of patent document 1 can obtain the tetracarboxylic-acid compound and its ester in which content of the by-product was fully reduced. It was a method. However, from the viewpoint of producing a raw material compound for producing a more transparent polyimide resin, a tetracarboxylic acid compound or an ester thereof is obtained in which the content of by-products is further reduced to a higher level. The emergence of a production method capable of this is desired.

International Publication No. 2011/099518

  The present invention has been made in view of the above-mentioned problems of the prior art, and is a norbornane-2-spiro-α-cycloalkanone-α′-spiro in which the content of by-products is reduced at a higher level. -2 "-norbornane-5,5", 6,6 "-tetracarboxylic acid and esters thereof, norbornane-2-spiro-α-cycloalkanone-α'-spiro- It is an object of the present invention to provide a process for producing 2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof.

  As a result of further earnest studies to achieve the above object, the present inventors have found that norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, A process for producing 6,6 ″ -tetracarboxylic acid and esters thereof is represented by 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ represented by the following general formula (1). By supplying carbon monoxide into a mixed solution containing -5 ″ -norbornenes, an alcohol, a palladium catalyst, and an oxidizing agent, the 5-norbornene-2-spiro-α-cycloalkanone- α′-spiro-2 ″ -5 ″ -norbornenes are reacted with the alcohol and the carbon monoxide to produce norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane. -5 Forming 5 ", 6,6" -tetracarboxylic acid and esters thereof, said norbornane-2-spiro- [alpha] -cycloalkanone- [alpha] '-spiro-2 "-norbornane-5,5" , 6,6 ″ -tetracarboxylic acid and a reaction mixture containing its ester, and after purifying the alcohol in the reaction mixture by an aromatic hydrocarbon having 6 to 9 carbon atoms To obtain the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof, By using the method comprising, norbornane-2-spiro-α-cycloalkanone-α′-spiro- represented by the following general formula (2) in which the content of by-products is reduced at a higher level 2 ''-Norvo Nan-5,5 ', 6,6' '- found that it becomes possible to obtain a tetracarboxylic acid and its esters, and have completed the present invention.

  That is, the process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof of the present invention Is the following general formula (1):

[In the formula (1), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and n is 0. An integer of ~ 12 is shown. ]
-Norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the formula: a mixed solution containing an alcohol, a palladium catalyst, and an oxidizing agent By supplying carbon monoxide into the 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornene with the alcohol and the carbon monoxide. The following general formula (2):

[In the formula (2), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 6 to 20 carbon atoms. 1 type selected from the group consisting of an aryl group and an aralkyl group having 7 to 20 carbon atoms, and n represents an integer of 0 to 12. ]
A norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof represented by: A reaction mixture containing the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof; Obtaining a step;
By purifying the alcohol in the reaction mixture after substitution with an aromatic hydrocarbon having 6 to 9 carbon atoms, the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″- Obtaining norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof;
It is the method characterized by including.

  In the above process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof The method of purification is preferably a method of purification by crystallization after replacing the alcohol in the reaction mixture with an aromatic hydrocarbon having 6 to 9 carbon atoms.

  In addition, the above-described norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof of the present invention are prepared. In the method, the purification method may be a method of purifying by an adsorptive separation method using an adsorbent after the alcohol in the reaction mixture is substituted with an aromatic hydrocarbon having 6 to 9 carbon atoms. Preferably, the adsorbent is at least one selected from the group consisting of activated alumina, activated clay, and activated carbon.

  Furthermore, the production of norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof of the present invention described above In the method, the aromatic hydrocarbon having 6 to 9 carbon atoms is preferably at least one selected from the group consisting of toluene, xylene, ethylbenzene, 1,3,5-trimethylbenzene and isopropylbenzene. .

  According to the present invention, norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, in which the content of by-products is reduced to a higher level, Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6, which makes it possible to obtain 6,6 ″ -tetracarboxylic acid and its esters , 6 ″ -tetracarboxylic acid and esters thereof can be provided.

2 is a graph showing an IR spectrum of the product obtained in Example 1. 2 is a graph showing a ¹ H-NMR (CDCl ₃ ) spectrum of the product obtained in Example 1. FIG.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  First, the process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof of the present invention Is a 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornene represented by the general formula (1), an alcohol, a palladium catalyst, By supplying carbon monoxide into a mixed solution containing an oxidizing agent, the 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes are obtained. By reacting with the alcohol and the carbon monoxide, norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″ represented by the above general formula (2) , 6,6 "-Te Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid which forms tracarboxylic acid and its esters And a step of obtaining a reaction mixture containing the esters thereof, and substituting the alcohol in the reaction mixture with an aromatic hydrocarbon having 6 to 9 carbon atoms, followed by purification to obtain the norbornane-2-spiro- obtaining α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof. is there. In the following, 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the above general formula (1) is sometimes simply referred to as “ Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 represented by the general formula (2) ” '', 6,6 ''-tetracarboxylic acid and esters thereof are sometimes simply referred to as “compound represented by the general formula (2)”. Here, first, the compound represented by the general formula (1), alcohol, palladium catalyst, oxidizing agent, and mixed solution used in the present invention will be described.

(Compound represented by the general formula (1))
In the present invention, the following general formula (1):

[In the formula (1), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and n is 0. An integer of ~ 12 is shown. ]
5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the formula:

In the general formula (1), R ¹ each independently represent a hydrogen atom, one selected from the group consisting of alkyl groups and fluorine atom having 1 to 10 carbon atoms. Such an alkyl group that can be selected as R ¹ is an alkyl group having 1 to 10 carbon atoms. When such a carbon number exceeds 10, when the compound represented by the said General formula (2) finally obtained is used as a raw material compound for polyimide manufacture, the heat resistance of the polyimide obtained will fall. Further, the number of carbon atoms of the alkyl group that can be selected as R ¹ is higher when the compound represented by the general formula (2) finally obtained is used as a raw material compound for polyimide production. From the viewpoint that a polyimide having excellent heat resistance is obtained, it is preferably 1 to 6, more preferably 1 to 5, still more preferably 1 to 4, and particularly preferably 1 to 3. preferable. Such an alkyl group that can be selected as R ¹ may be linear or branched.

Moreover, as R < ¹ > in the said General formula (1), it is a hydrogen atom or a C1-C10 alkyl group each independently from a viewpoint that a high heat resistance is acquired when a polyimide is manufactured. Among these, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, or an isopropyl group is more preferable from the viewpoint of easy availability of raw materials and easier purification. Or it is especially preferable that it is a methyl group. Moreover, it is especially preferable that several R < ¹ > in such a formula is the same from viewpoints of the ease of refinement | purification etc.

  Moreover, n in the said General formula (1) shows the integer of 0-12. When the value of n exceeds the upper limit, it becomes difficult to purify the compound represented by the general formula (2). Further, the upper limit value of the numerical value range of n in the general formula (1) is more preferably 5 and particularly preferably 3 from the viewpoint of easier purification. Further, the lower limit of the numerical range of n in the general formula (1) is more preferably 1 and particularly preferably 2 from the viewpoint of the stability of the raw material. Thus, it is particularly preferable that n in the general formula (1) is an integer of 2 to 3.

The alkyl group having 1 to 10 carbon atoms R ^2, may be selected as R ³ in the general formula (1) is the same as the alkyl group having 1 to 10 carbon atoms which can be selected as R ¹ is there. As such substituents that can be selected as R ² and R ³ , from the viewpoint of ease of purification, among the above substituents, among the above substituents, a hydrogen atom, a carbon number of 1 to 10 (preferably 1 to 6, more preferably 1). -5, more preferably 1-4, particularly preferably 1-3) alkyl group, and particularly preferably a hydrogen atom or a methyl group.

In the general formula (1), when a plurality of R ² are present (when n is 2 or more), the plurality of R ² may be the same or different. From the viewpoint of easiness of purification and the like, it is preferable that they are the same. In the general formula (1), when a plurality of R ³ are present (when n is 2 or more), the plurality of R ³ may be the same or different. From the viewpoint of easiness of purification and the like, it is preferable that they are the same. Furthermore, R ² and R ³ in the general formula (1) are more preferably the same from the viewpoint of ease of purification and the like.

  As such 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the general formula (1), International Publication No. 2011/099518 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes such as 5-norbornene-2-spiro-α-cyclopentanone -Α'-spiro-2 "-5" -norbornene [also known as: 5-norbornene-2-spiro-2'-cyclopentanone-5'-spiro-2 "-5" -norbornene] 5-norbornene-2-spiro-α-cyclohexanone-α′-spiro-2 ″ -5 ″ -norbornene [alias: 5-norbornene-2-spiro-2′-cyclohexanone-6′-spiro-2 ″ -5 "-norbornene] and the like can be used as appropriate.

  Further, the method for producing such a compound represented by the general formula (1) is not particularly limited, and a known method can be appropriately employed. For example, International Publication No. 2011/099517 and International Publication The manufacturing method of 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornene described in 2011/099518 can be appropriately used.

(alcohol)
The alcohol according to the present invention includes the following general formula (3):
R ^a OH (3)
[In the formula (3), R ^a is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, an aryl group having 6 to 20 carbon atoms and a carbon number. It is one selected from the group consisting of 7 to 20 aralkyl groups (a hydrogen atom among atoms and groups that can be selected as R ⁴ , R ⁵ , R ⁶ or R ^{7 in} the general formula (2) described later) It is the same as other things.) ]
The alcohol represented by these is preferable.

The alkyl group that can be selected as R ^a in the general formula (3) is an alkyl group having 1 to 10 carbon atoms. When the number of carbon atoms of such an alkyl group exceeds 10, purification of the compound represented by the general formula (2) finally obtained tends to be difficult. As the number of carbon atoms in such alkyl groups which may be selected as R ^a, from the viewpoint of purification becomes easier, more preferably from 1 to 5, more preferably 1-3. Further, such an alkyl group that can be selected as R ^a may be linear or branched.

In addition, the cycloalkyl group that can be selected as R ^a in the general formula (3) is a cycloalkyl group having 3 to 10 carbon atoms. When the number of carbon atoms of such a cycloalkyl group exceeds 10, purification of the compound represented by the general formula (2) finally obtained tends to be difficult. As the number of carbon atoms of the cycloalkyl group such may be selected as R ^a, from the viewpoint of purification it becomes easier, more preferably 3-8, more preferably 5-6.

Furthermore, the alkenyl group that can be selected as R ^a in the general formula (3) is an alkenyl group having 2 to 10 carbon atoms. When the number of carbon atoms of such an alkenyl group exceeds 10, purification of the compound represented by the general formula (2) finally obtained tends to be difficult. As the number of carbon atoms in such an alkenyl group which may be selected as R ^a, from the viewpoint of purification becomes easier, more preferably from 2 to 5, more preferably 2-3.

In addition, the aryl group that can be selected as R ^a in the general formula (3) is an aryl group having 6 to 20 carbon atoms. When the number of carbon atoms in the aryl group exceeds 20, purification of the compound represented by the general formula (2) finally obtained tends to be difficult. As the number of carbon atoms of such aryl groups that may be selected as R ^a, from the viewpoint of purification it becomes easier, more preferably 6-10, more preferably 6-8.

The aralkyl group that can be selected as R ^a in the general formula (3) is an aralkyl group having 7 to 20 carbon atoms. When the carbon number of such an aralkyl group exceeds 20, purification of the compound represented by the general formula (2) finally obtained tends to be difficult. As the number of carbon atoms in such an aralkyl group that may be selected as R ^a, from the viewpoint of purification it becomes easier, more preferably 7-10, more preferably 7-9.

Furthermore, as R ^a in the general formula (3), from the viewpoint of easier purification, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, It is preferably sec-butyl, t-butyl, 2-ethylhexyl group, cyclohexyl group, allyl group, phenyl group or benzyl group, and particularly preferably methyl group.

  Thus, as said alcohol, C1-C10 alkyl alcohol, C3-C10 cycloalkyl alcohol, C2-C10 alkenyl alcohol, C6-C20 aryl alcohol, It is preferable to use aralkyl alcohol having 7 to 20 carbon atoms. Specific examples of such alcohols include methanol, ethanol, butanol, allyl alcohol, cyclohexanol, benzyl alcohol, etc. Among them, methanol and ethanol are preferred from the viewpoint that purification of the resulting compound is easier. Is more preferable, and methanol is particularly preferable. Such alcohols may be used alone or in combination of two or more.

(Palladium catalyst)
The palladium catalyst according to the present invention is not particularly limited, and a known catalyst containing palladium can be used as appropriate, for example, an inorganic acid salt of palladium, an organic acid salt of palladium, a catalyst having palladium supported on a carrier, and the like. Is mentioned. Examples of the known catalyst containing palladium include palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, palladium propionate, palladium carbon, palladium alumina, and palladium black.

Moreover, as such a palladium catalyst, the production of by-products can be more sufficiently suppressed, and from the viewpoint that the compound represented by the general formula (2) can be produced with higher selectivity. The following general formula (4):
Pd ₃ (CH ₃ COO) ₅ (NO ₂ ) (4)
Palladium catalyst containing 10 mol% or more of palladium acetate having a nitrite ligand represented by the following formula (hereinafter referred to as palladium acetate having a nitrite ligand represented by the general formula (4), Pd ₃ (OAc) ₅ (NO ₂ ) ”is preferred.

In the palladium catalyst containing 10 mol% or more of palladium acetate having such a nitrite ligand (Pd ₃ (OAc) ₅ (NO ₂ )) in terms of metal, the content ratio of palladium acetate having the nitrite ligand is the lower limit. If it is less than 1, it is difficult to sufficiently suppress the production of by-products, and it tends to be difficult to produce the compound represented by the general formula (2) with a sufficiently high selectivity. In addition, as the palladium catalyst, acetic acid having a nitrite ligand can be used from the viewpoint that the production of by-products can be suppressed at a higher level and an ester compound can be produced with higher selectivity. The content ratio of palladium (Pd ₃ (OAc) ₅ (NO ₂ )) is preferably 30% by mole or more and 40% by mole or more in terms of metal (based on the total amount of palladium in the palladium catalyst). More preferably, it is more preferably 50 mol% or more, and particularly preferably 70 mol% to 100 mol%.

  In addition, the component (other catalyst component) other than palladium acetate having a nitrous acid ligand that can be contained in the palladium catalyst is not particularly limited, and the compound represented by the general formula (1) is carbon monoxide and alcohol. Of known palladium-based catalyst components (palladium chloride, palladium nitrate, palladium sulfate, palladium acetate, palladium propionate, palladium carbon, palladium, which can be used in the reaction with alkoxycarbonyl (when alkoxycarbonylating (esterifying)) Alumina, palladium black, etc.) can be used as appropriate.

Moreover, as a component other than palladium acetate having a nitrite ligand that can be contained in such a palladium catalyst (palladium-based catalyst component), from the viewpoint of suppressing the generation of by-products such as a polymer and improving selectivity. It is preferable to use palladium acetate. Thus, as the palladium catalyst, palladium acetate having a nitrite ligand having a nitrite ligand (Pd ₃ (OAc) ₅ (NO ₂ )) content ratio of 10 mol% or more and palladium acetate, And a catalyst made of palladium acetate having a nitrite ligand (Pd ₃ (OAc) ₅ (NO ₂ )) can be used more suitably.

Incidentally, no particular restriction on a method for the production of palladium acetate _{(Pd 3 (OAc) 5 (} NO 2)) having such a nitrite ligands, can be appropriately used a known method, for example, The method described in pages 1989 to 1992 of Dalton Trans (vol. 11) published on June 7, 2005 (author: Vladimir I, Bakhmutov, et al.) May be used as appropriate. . That is, as a method for producing palladium acetate having such a nitrous acid ligand (Pd ₃ (OAc) ₅ (NO ₂ )), for example, after dispersing metallic palladium in acetic acid, nitric acid is dropped, The obtained mixed liquid is refluxed with stirring to be reacted by heating and stirring. From the obtained solid content, purple columnar crystals (formula: Pd ₃ (OAc) ₅ (NO ₂ )) ) May be employed by taking out. When employing a method for producing palladium acetate having such a nitrite ligand (Pd ₃ (OAc) ₅ (NO ₂ )), the temperature condition for heating and stirring the mixed solution is set to 60 to 150. It is preferable to set it as ° C. In addition, after the mixed solution is heated and stirred, from the viewpoint of growing crystals in the mixed solution, the pressure is set to 100 to 100 ° C under a mild and mild condition (for example, using an evaporator at a temperature of 20 to 80 ° C). After reducing the pressure at a stretch until the pressure reaches about 500 hPa, it is preferable to further concentrate in the reduced pressure state (about 100 to 500 hPa) under the condition that the pressure is reduced by spending 10 to 30 minutes until the pressure reaches about 1 to 5 hPa. And after concentrating the said liquid mixture in this way, a crystal | crystallization can be deposited by cooling the said liquid mixture to about room temperature. Incidentally, during the crystal precipitated in this _{way, Pd 3 (OAc) 5 (} NO 2) from the crystal may also be included in the compounds other than crystal, palladium acetate having a nitrite ligand _(Pd 3 (OAc ) ₅ (NO ₂ )), a Pd ₃ (OAc) ₅ (NO ₂ ) crystal (purple columnar crystal) may be fractionated and extracted from the crystal by appropriately using a known method. In addition, when using such a manufacturing method, after obtaining the said crystal | crystallization, you may implement suitably the process etc. which remove an impurity and refine | purify. In addition, as the palladium catalyst according to the present invention, palladium acetate (Pd ₃ (OAc) ₅ (NO ₂ )) having a nitrite ligand obtained as described above may be used as it is, or the above-described moles may be used. You may use as a mixture which mixed suitably the other component in the range of ratio. In addition, the structure of palladium acetate (Pd ₃ (OAc) ₅ (NO ₂ )) having such a nitrite ligand can be confirmed by NMR measurement or the like.

(Oxidant)
As an oxidizing agent according to the present invention, in a reaction (oxidative alkoxycarbonylation (esterification) reaction) in which an ester group is introduced by reacting a compound represented by the general formula (1) with carbon monoxide and an alcohol, when the Pd ²⁺ of the palladium catalyst is reduced to Pd ^0, if the Pd ⁰ to can be oxidized to Pd ²⁺ compounds (compounds capable of re-oxidize the reduced palladium catalyst) Well, not particularly limited, for example, copper compounds such as copper chloride, copper acetate, Cu (acac) ₂ , copper benzoate, copper carbonate, copper nitrate; iron compounds such as iron chloride, iron acetate, iron sulfate, iron nitrate Manganese compounds such as manganese chloride, manganese acetate and manganese oxide; zinc compounds such as zinc chloride and zinc acetate; vanadium compounds such as vanadium chloride; chromium chloride, tin chloride and bis chloride Scan, mercuric chloride, chlorides such as phosphorus chloride; phosphovanadotungstic heteropoly acids such as molybdic acid; hydrogen peroxide; and the like.

More specifically, as such an oxidizing agent, cupric chloride, cupric nitrate, cupric sulfate, cupric acetate, ferric chloride, ferric nitrate, ferric sulfate , Ferric acetate, manganese dioxide, manganese acetate and the like. Incidentally, the Pd ⁰ by utilizing the gas components such as oxygen or air with an oxidant of a metal or metal compound such as (above copper compounds, etc.) may be oxidized to Pd ^2+. Moreover, as such an oxidizing agent, a copper compound is preferable from the viewpoint that Pd ⁰ can be efficiently oxidized to Pd ²⁺ , and copper chloride is particularly preferable.

(Mixture)
The liquid mixture according to the present invention comprises 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the above general formula (1), alcohol And a palladium catalyst and an oxidizing agent.

  Although it does not restrict | limit especially as content of the compound represented by General formula (1) in such a liquid mixture, It is preferable to set it as 0.001-500 g / L, and it shall be 1-100 g / L. More preferably, it is more preferable to set it as 10-100 g / L. If such a concentration is less than the lower limit, the reaction rate tends to decrease and the yield of the target product tends to decrease. On the other hand, if the concentration exceeds the upper limit, the reaction rate improves and the reaction proceeds at a stretch, making it difficult to control the reaction In addition, the raw materials and intermediates remain and the yield tends to decrease.

  The alcohol content in such a mixed solution is not particularly limited as long as the compound represented by the general formula (2) can be obtained. For example, in the general formula (2) The alcohol may be added to an amount theoretically necessary (theoretical amount) or more (more preferably an amount exceeding the theoretical amount) to obtain the represented compound, and the excess alcohol may be used as a solvent as it is. Thus, in the present invention, the alcohol (for example, methanol, ethanol, propanol, etc.) can be used as a solvent while being used as a raw material for the reaction, and it is easier to produce and purify the resulting ester compound. From the viewpoint of becoming, it is preferable to use the alcohol as a solvent.

  As the content (usage amount) of the palladium catalyst in such a mixed solution, the molar amount of palladium in the palladium catalyst (molar amount in terms of Pd metal of the palladium catalyst) is represented by the general formula (1). 0.00001 to 1 times mol (more preferably 0.0001 to 1 times mol, still more preferably 0.001 to 0.1 times mol, particularly preferably 0.0025 to 0.1 times mol), , And most preferably 0.0025 to 0.02 times mole). When the amount (molar amount) of the palladium catalyst used is less than the lower limit, the reaction rate tends to decrease and the yield of the target product tends to decrease. On the other hand, when the upper limit is exceeded, the reaction rate improves and the reaction proceeds at a stretch. It tends to be difficult to control the reaction.

  The content (usage amount) of the oxidizing agent in the mixed solution is 2 to 16 times (more preferably 2 to 8 times, particularly preferably 2) the molar amount of the compound represented by the general formula (1). It is preferable to set it as a molar amount of ˜6 times. When the amount (molar amount) of the oxidizing agent used is less than the lower limit, the reaction rate tends to decrease and the yield of the target product tends to decrease. On the other hand, when the upper limit is exceeded, the reaction rate improves and the reaction proceeds at a stretch. It tends to be difficult to control the reaction.

  In such a mixed solution, another solvent may be added to the alcohol. Examples of such other solvents include aromatic solvents such as benzene, toluene, xylene, and chlorobenzene; ether solvents such as ether, THF, and dioxane; ester solvents such as ethyl acetate; hexane, cyclohexane, heptane, Hydrocarbon solvents such as pentane; nitrile solvents such as acetonitrile and benzonitrile; halogen solvents such as methylene chloride and chloroform; ketone solvents such as acetone and MEK; amide solvents such as DMF, NMP, DMI, and DMAc Can be mentioned.

  Furthermore, in the mixed solution, since an acid is by-produced from the oxidizing agent or the like during the reaction, a base may be further added to remove the acid. As such a base, fatty acid salts such as sodium acetate, sodium propionate, and sodium butyrate are preferable. Further, the amount of such base used may be appropriately adjusted according to the amount of acid generated.

  Hereinabove, the compound represented by the general formula (1), the alcohol, the palladium catalyst, the oxidizing agent, and the mixed solution used in the present invention have been described. Next, norbornane-2-spiro-α-cycloalkanone-α′- A process for producing spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof will be described.

(Manufacturing process)
The process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof according to the present invention includes: 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the above general formula (1), alcohol, palladium catalyst, and oxidizing agent By supplying carbon monoxide into a mixed solution containing the above, the 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornene is converted to the alcohol. And norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6 represented by the above general formula (2). , 6 ''-tetracarboxylic acid and its esters Reaction mixture containing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof A step of obtaining a liquid, and purifying the alcohol in the reaction mixture after substitution with an aromatic hydrocarbon having 6 to 9 carbon atoms, whereby the norbornane-2-spiro-α-cycloalkanone-α′- Obtaining spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof.

(Step of obtaining a reaction mixture)
In the step of obtaining the reaction mixture, first, carbon monoxide is supplied into the mixture. A method for supplying such carbon monoxide is not particularly limited, and the carbon monoxide can be supplied into the mixed solution by bringing the mixed solution into contact with the carbon monoxide. A method can be appropriately employed. As a method for supplying such carbon monoxide, for example, when the mixed liquid is introduced into the reaction vessel, carbon monoxide (or a mixed gas thereof) is introduced into the atmospheric gas in the reaction vessel. In this case, a method may be adopted in which the mixed liquid and the carbon monoxide are brought into contact with each other, and carbon monoxide is supplied into the mixed liquid from an interface between an atmospheric gas and the mixed liquid. A method of supplying carbon monoxide by bubbling may be employed. Thus, as a method for supplying carbon monoxide into the mixed solution, a method capable of supplying carbon monoxide into the mixed solution can be appropriately employed.

  In addition, when carbon monoxide is supplied into the mixed solution, the carbon monoxide is 0.002 to 0.2 mole equivalent / minute (more preferably 0 to the compound represented by the general formula (1)). 0.005 to 0.1 molar equivalent / minute, more preferably 0.005 to 0.05 molar equivalent / minute) (feed rate). When the supply ratio of carbon monoxide is less than the lower limit, the reaction rate tends to be slow, and by-products such as polymers tend to be generated. On the other hand, when the upper limit is exceeded, the reaction rate is improved and the reaction is performed at once. Tends to become difficult to control the reaction. In addition, since 4 mol equivalent of carbon monoxide theoretically reacts with 1 mol of the compound of the general formula (1) as the raw material, for example, the ratio (feed rate) is 0.1 mol equivalent / min. Then, in order to introduce 4 molar equivalents of the theoretical amount with respect to 1 mol of the compound of the general formula (1), 40 minutes (4 [molar equivalent] /0.1 [molar equivalent / minute] = 40 Minutes). As a method for supplying carbon monoxide at such a supply rate, it is preferable to employ a method of supplying carbon monoxide by bubbling into the mixed solution.

  Further, as a method of supplying carbon monoxide into the mixed solution, it is preferable to employ a method of supplying carbon monoxide by bubbling into the mixed solution. In the mixed solution, the general formula (1) The specific ratio (feed rate: preferably 0.002 to 0.2 molar equivalent / minute, more preferably 0.005 to 0.1 molar equivalent / minute, still more preferably 0.002 to the compound represented. It is more preferable to employ a method in which carbon monoxide is supplied by bubbling at 005 to 0.05 mole equivalent / minute). In this way, by supplying carbon monoxide into the mixed solution by bubbling (preferably at the specific ratio described above by bubbling), it becomes possible to make carbon monoxide reach the entire mixed solution more sufficiently. In addition, since the reaction can proceed at a sufficient reaction rate, the reaction for introducing the ester group tends to proceed more efficiently. That is, by such bubbling operation, compared with the case where carbon monoxide is introduced into the atmosphere gas of the reaction vessel, it becomes possible to make carbon monoxide reach the entire mixed solution more sufficiently. It is possible to contact carbon monoxide more efficiently with the compound or catalyst represented by the general formula (1) in the inside, thereby enabling the reaction for introducing an ester group to proceed more efficiently. Become. Such an effect is particularly noticeable when the reaction vessel is made larger (when a larger reaction vessel is used and a larger amount of liquid mixture is used, carbon monoxide is simply introduced into the atmosphere gas of the reaction vessel. Even if it is introduced, carbon monoxide is sufficiently brought into contact with the compound or catalyst represented by the general formula (1) existing at the bottom of the container (site farther from the interface between the liquid phase and the gas phase). Because it tends to be difficult.)

  In addition, since by-products such as a polymer that can be generated during the reaction cause the reaction product to be colored, it is desired to further suppress the formation of the polymer from the viewpoint of improving the hue of the product. Here, when carbon monoxide is supplied into the mixture at a specific ratio by bubbling as described above, it is desired to use it from the viewpoint of industrial mass production. Even when lower pressure conditions such as normal pressure are adopted, the reaction can be allowed to proceed in a sufficiently short time, and the generation of by-products such as polymer (heavy material) is more sufficiently suppressed. It tends to be possible. Also from such a viewpoint, it is preferable to employ a method of supplying carbon monoxide by bubbling into the mixed solution as a method of supplying carbon monoxide into the mixed solution.

  In addition, the specific method of bubbling is not particularly limited, and a known bubbling method can be appropriately employed. For example, a so-called bubbling nozzle, a tube having a large number of holes, or the like can be used as appropriate. Carbon monoxide may be bubbled and supplied at the above ratio. The method for controlling the supply rate of carbon monoxide at the time of bubbling is not particularly limited, and a known control method may be adopted as appropriate. The method is specific to the bubbling nozzle, a tube provided with a large number of holes, You may employ | adopt the method of controlling the supply rate of carbon monoxide to the said ratio using the well-known apparatus which can supply gas in a ratio. In particular, when a reaction vessel is used, it is preferable to adjust a bubbling nozzle, a pipe and the like near the bottom of the vessel. This is to promote contact between the compound represented by the general formula (1) present at the bottom and carbon monoxide supplied from a bubbling nozzle or the like.

  When a method other than bubbling is adopted as a method for supplying carbon monoxide into the mixed solution (for example, when using a reaction vessel, carbon monoxide or a mixed gas thereof is added to the atmospheric gas in the reaction vessel. The method for controlling the supply rate of carbon monoxide is not particularly limited in the case of adopting the introduction method, for example, and the supply rate of carbon monoxide into the liquid mixture is changed, for example, by appropriately changing the pressure. A controllable method can be appropriately employed.

  Moreover, by supplying carbon monoxide to the mixed solution in this way (preferably, as described above, carbon monoxide is added to the mixed solution with respect to the compound represented by the general formula (1). In the liquid phase (in the mixed solution), in the presence of a palladium catalyst and an oxidizing agent, the compound represented by the general formula (1) is reacted with the alcohol and the carbon monoxide. It becomes possible.

In such a reaction, by supplying carbon monoxide (CO) to the mixed solution, the alcohol (R ^a OH) and carbon monoxide (CO) and carbon monoxide (CO) are mixed with the catalyst in the presence of a palladium catalyst and an oxidizing agent. The compound represented by the general formula (1) is reacted to give 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″-represented by the general formula (1). In the olefin part in 5 ″ -norbornenes, the following general formula (5):
-COOR ^a (5)
Wherein (5), ^{R a} is synonymous with ^{R a} in formula (3) (also synonymous what its suitable.). ]
Introduced in represented by an ester group (such ester groups per position to be introduced may be the same or different are R ^a.), Thereby a compound represented by the general formula (2) Reaction to obtain (esterification reaction).

  In such an esterification reaction, it is sufficient that the carbon monoxide can supply an amount necessary for esterification into the mixed solution. Therefore, the gas used for supplying carbon monoxide into the mixed solution may be a high-purity gas of carbon monoxide or other gas, such as carbon monoxide, A mixed gas obtained by mixing carbon and a gas inert to the esterification reaction (for example, nitrogen or the like) may be used, and further, synthesis gas, coal gas, or the like may be used. In addition, as a gas used for supplying carbon monoxide into the mixed solution, carbon monoxide, carbon monoxide and other gases (nitrogen, from the viewpoint of not affecting the catalyst and the oxidant). A mixed gas of air, oxygen, hydrogen, carbon dioxide, argon, etc.) is preferable.

  In addition, the reaction temperature condition in the esterification reaction is not particularly limited, but is 0 ° C to 200 ° C {more preferably 0 ° C to 100 ° C, more preferably about 10 to 60 ° C, particularly preferably 20 to 50 ° C. It is preferable that the temperature is about the same. When such a reaction temperature exceeds the upper limit, the yield tends to decrease. On the other hand, when the reaction temperature is less than the lower limit, the reaction rate tends to decrease. The reaction time for the esterification reaction is not particularly limited, but is preferably about 30 minutes to 24 hours.

  Further, the atmospheric gas in the esterification reaction is not particularly limited, and a gas that can be used for the esterification reaction can be appropriately used. For example, an inert gas (nitrogen, argon, etc.) for the esterification reaction , Carbon monoxide, mixed gas of carbon monoxide and other gas (nitrogen, air, oxygen, hydrogen, carbon dioxide, argon, etc.), from the viewpoint of not affecting the catalyst and oxidant, Carbon monoxide, a gas inert to the esterification reaction, and a mixed gas of carbon monoxide and a gas inert to the esterification reaction are preferable. In addition, when adopting a method of introducing carbon monoxide by bubbling as a method of supplying carbon monoxide into the mixed solution, for example, the atmosphere gas is made of a gas inert to the esterification reaction before the reaction. Alternatively, the reaction may be started by bubbling as described above, and as a result, the reaction may proceed so that the atmospheric gas becomes a mixed gas of carbon monoxide and a gas inert to the esterification reaction.

  Further, the pressure condition in the esterification reaction (atmospheric gas pressure condition: when the reaction is allowed to proceed in the reaction vessel) is not particularly limited, but is 0.05 MPa to 15 MPa. The pressure is preferably normal pressure (0.1 MPa [1 atm]) to 15 MPa, more preferably 0.1 MPa to 10 MPa, and particularly preferably 0.11 MPa to 5 MPa. When the pressure condition is less than the lower limit, the reaction rate tends to decrease and the yield of the target product tends to decrease. On the other hand, when the upper limit is exceeded, the reaction rate improves and the reaction proceeds at a stretch, making it difficult to control the reaction. There is a tendency that facilities that can carry out the reaction are limited.

  In such a reaction, the pressure of carbon monoxide in the atmospheric gas is not particularly limited, but is preferably 0.05 MPa to 15 MPa, and is set to normal pressure (about 0.1 MPa [1 atm]) to 10 MPa. Is more preferable. If the pressure is less than the lower limit, the reaction rate tends to decrease and the yield of the target product tends to decrease.On the other hand, if the pressure exceeds the upper limit, the reaction rate improves and the reaction proceeds at a stretch and it is difficult to control the reaction. There is a tendency that facilities that can carry out the reaction are limited. In addition, by supplying carbon monoxide by bubbling, carbon monoxide can be mixed in the atmospheric gas as a result. However, the pressure (partial pressure) of carbon monoxide in the atmospheric gas falls within the above range. Thus, the reaction may proceed. As a method of supplying carbon monoxide into the mixed solution, the mixed solution and the carbon monoxide are brought into contact with each other by introducing carbon monoxide (or a mixed gas thereof) into the atmospheric gas in the reaction vessel. When the method of supplying the carbon monoxide into the mixed solution is adopted, the pressure condition (more preferably, normal pressure (about 0.1 MPa [1 atm]) to 10 MPa) is maintained. It is preferable to employ a method of continuously introducing carbon monoxide into the atmospheric gas.

In order to make R ⁴ , R ⁵ , R ⁶ or R ⁷ in the general formula (2) a hydrogen atom, after introducing a group represented by the above formula: —COOR ^a by the esterification reaction, Decomposition treatment or transesterification with carboxylic acid may be performed. The method of such a reaction is not particularly limited, and a known method capable of converting the group represented by the formula: —COOR ^a into the formula: —COOH can be appropriately employed.

  In addition, by performing esterification reaction, hydrolysis and the like in this manner, the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 is contained in the mixed solution. '', 6,6 ''-tetracarboxylic acid and its esters can be formed, and a reaction mixture containing the compound can be obtained. That is, in the present invention, as described above, carbon monoxide is supplied into the mixed solution, and the compound represented by the general formula (1) is converted into the alcohol in the presence of a palladium catalyst and an oxidizing agent. And by reacting with the carbon monoxide, the following general formula (2):

[In the formula (2), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 6 to 20 carbon atoms. 1 type selected from the group consisting of an aryl group and an aralkyl group having 7 to 20 carbon atoms, and n represents an integer of 0 to 12. ]
Is formed. Thereby, it becomes possible to obtain a mixed solution (reaction mixed solution) containing the compound after the reaction.

R ¹ in the general formula (2) is the same as the R ¹ in formula (1), also the same as R ¹ in the general formula (1) as its preferred . Further, ^R 2, ^{R 3} in the general formula (2) is the same as the ^R 2, ^{R 3} in the general formula (1), ^{R 2} of the preferred ones also in formula (1) , R ³ . Furthermore, n in the general formula (2) is an integer similar to n in the general formula (1), and a suitable value thereof is also the same as n in the general formula (1).

Moreover, the alkyl group which can be selected as R < ⁴ >, R < ⁵ >, R < ⁶ >, R < ⁷ > in the said General formula (2) is a C1-C10 alkyl group. When the carbon number of such an alkyl group exceeds 10, purification becomes difficult. Moreover, as carbon number of the alkyl group which can be selected as such R < ⁴ >, R < ⁵ >, R < ⁶ >, R < ⁷ >, it is more preferable that it is 1-5 from a viewpoint that refinement | purification becomes easier, 3 is more preferable. Further, such an alkyl group that can be selected as R ⁴ , R ⁵ , R ⁶ , and R ⁷ may be linear or branched.

Cycloalkyl ^{groups R 4,} R ^5, may be selected as R 6, ^{R 7} in the general formula (2) is a cycloalkyl group having a carbon number of 3-10. If the number of carbon atoms in such a cycloalkyl group exceeds 10, purification becomes difficult. The number of carbon atoms of the cycloalkyl group that can be selected as R ⁴ , R ⁵ , R ⁶ , or R ⁷ is more preferably 3 to 8 from the viewpoint of easier purification. More preferably, it is -6.

Furthermore, the alkenyl group that can be selected as R ⁴ , R ⁵ , R ⁶ , R ^{7 in the} general formula (2) is an alkenyl group having 2 to 10 carbon atoms. When the carbon number of such an alkenyl group exceeds 10, purification becomes difficult. Moreover, as carbon number of the alkenyl group which can be selected as such R < ⁴ >, R < ⁵ >, R < ⁶ >, R < ⁷ >, it is more preferable that it is 2-5 from a viewpoint that refinement | purification becomes easier, 3 is more preferable.

^{Further, R 4, R 5, R} 6, an aryl group which can be selected as ^{R 7} in the general formula (2) is an aryl group having 6 to 20 carbon atoms. If the number of carbon atoms in such an aryl group exceeds 20, purification becomes difficult. In addition, such ^{R 4, R 5, R 6} , the number of carbon atoms of the aryl group which may be selected as ^{R 7,} from the viewpoint of purification becomes easier, more preferably 6 to 10, 6 More preferably, it is 8.

^{Further, R 4, R 5, R} 6, an aralkyl group which may be selected as ^{R 7} in the general formula (2) is an aralkyl group having a carbon number of 7-20. If the number of carbon atoms in such an aralkyl group exceeds 20, purification becomes difficult. Further, the number of carbon atoms of the aralkyl group that can be selected as R ⁴ , R ⁵ , R ⁶ , R ⁷ is more preferably 7-10, from the viewpoint of easier purification. More preferably, it is 9.

Furthermore, R ⁴ , R ⁵ , R ⁶ , and R ^{7 in the} general formula (2) are each independently a hydrogen atom, a methyl group, an ethyl group, or n-propyl from the viewpoint of easier purification. Group, isopropyl group, n-butyl group, isobutyl group, sec-butyl, t-butyl, 2-ethylhexyl group, cyclohexyl group, allyl group, phenyl group or benzyl group, particularly preferably methyl group. preferable. In the general formula (2), R ⁴ , R ⁵ , R ⁶ and R ⁷ may be the same or different, but from the viewpoint of synthesis, they may be the same. More preferred.

(Purification process)
In this invention, after obtaining the said reaction liquid mixture as mentioned above, after substituting the alcohol in the said reaction liquid liquid by the C6-C9 aromatic hydrocarbon, it refine | purifies. By such purification, the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid having higher purity and The esters can be obtained. In addition, such a purification step can sufficiently remove impurities and can provide a product in which coloring is suppressed at a higher level.

  In such a purification step, as described above, it is necessary to replace the alcohol in the mixed solution after the reaction with an aromatic hydrocarbon having 6 to 9 carbon atoms (more preferably 7 to 9 carbon atoms). is there. By using such an aromatic hydrocarbon having 6 to 9 carbon atoms (more preferably 7 to 9), the compound represented by the general formula (2) is sufficiently dissolved. Metal compounds that can be contained therein (for example, such a copper compound in the case of using a copper catalyst as a palladium catalyst or the oxidizing agent) can be made in a state of not being dissolved, and can be reacted more efficiently. It becomes possible to obtain (recover) the compound in the mixed solution. In addition, when the carbon number of such aromatic hydrocarbons exceeds the upper limit, purification tends to be difficult.

  Examples of the aromatic hydrocarbon having 6 to 9 carbon atoms include benzene, toluene, xylene (o-xylene, m-xylene, p-xylene, mixed xylene), ethylbenzene, 1,2,3-trimethylbenzene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, isopropylbenzene, n-propylbenzene, and the like are mentioned. From the viewpoint of industrial use and availability, among them, toluene, xylene, ethylbenzene, 1,3,5-trimethylbenzene and isopropylbenzene are preferably used, and toluene, xylene and isopropylbenzene are more preferably used.

  Moreover, it does not restrict | limit especially as a method of substituting the alcohol in the liquid mixture after the said reaction with the aromatic hydrocarbon having 6-9 carbon atoms (more preferably 7-9), and adopts a known method as appropriate. For example, alcohol is distilled off from the mixed solution after the reaction (for example, by distillation using an evaporator, etc.) to obtain a solid containing a reaction product, Thus, a method of adding an aromatic hydrocarbon having 6 to 9 (more preferably 7 to 9) carbon atoms may be employed.

  Further, such a purification step is not particularly limited except that the alcohol in the reaction mixture is purified after substitution with an aromatic hydrocarbon having 6 to 9 carbon atoms, and a known method is appropriately employed. be able to. Specific examples of such purification include a crystallization method (including a recrystallization method), an adsorption separation method, and the like.

  Moreover, as such a purification method, after substituting the alcohol in the reaction mixture with an aromatic hydrocarbon having 6 to 9 carbon atoms, crystallization is followed by purification (crystallization method), and A method in which the alcohol in the reaction mixture is substituted with an aromatic hydrocarbon having 6 to 9 carbon atoms and then purified by an adsorption separation method using an adsorbent (adsorption separation method) is preferable.

  In addition, in such a purification process, it is preferable to perform the process of isolate | separating a palladium catalyst and an oxidizing agent from the said reaction liquid mixture prior to a purification process. The step of separating such a palladium catalyst or oxidizing agent is not particularly limited, and a known method (for example, a washing step) may be appropriately employed.

  Moreover, since it becomes possible to isolate | separate the said palladium catalyst and an oxidizing agent more efficiently as a process of isolate | separating such a palladium catalyst and an oxidizing agent, carbon number has 6 carbon atoms. After substituting with ˜9 aromatic hydrocarbons and before purification, heating to 40 to 150 ° C. and filtration (hereinafter, this step is sometimes simply referred to as “hot filtration step”). Is preferably adopted.

  In such a hot filtration step, the reaction product can be sufficiently dissolved in the aromatic hydrocarbon by heating to 40 to 150 ° C., while the aromatic hydrocarbon can be dissolved. Since the palladium catalyst and the oxidizing agent are not basically dissolved therein, the palladium catalyst and the oxidizing agent can be easily separated by filtration, and the palladium catalyst and the oxidizing agent can be easily recycled. It can also be recovered in the form. According to such a hot filtration process, for example, by performing a washing process using a large amount of hydrochloric acid or the like, there is no need to remove the oxidant and the like, and there is no need to remove a large amount of waste water. This process is a process suitable for more industrial mass production. Hereinafter, the hot filtration step suitable as a step of separating the palladium catalyst and the oxidizing agent will be described.

  Moreover, in the said hot filtration process, it obtains after substituting the alcohol in the liquid mixture (reaction liquid mixture) after the said reaction by the C6-C9 (more preferably 7-9) aromatic hydrocarbon. It is preferable to heat the resulting mixed liquid (hereinafter, simply referred to as “second mixed liquid” in some cases) to 40 to 150 ° C. (more preferably 60 to 140 ° C., still more preferably 70 to 130 ° C.). When the heating temperature is less than the lower limit, the compound represented by the general formula (2) tends not to be sufficiently dissolved in the solvent. On the other hand, when the upper limit is exceeded, the compound is represented by the general formula (2). The yield of the compound tends to decrease due to decomposition of the compound.

  Furthermore, the heating time of the second mixed solution is not particularly limited, but is preferably 0.5 to 15 hours, and more preferably 0.5 to 5 hours. If the heating time is less than the lower limit, the compound represented by the general formula (2) tends not to be sufficiently dissolved in the solvent, and if the heating time exceeds the upper limit, the compound represented by the general formula (2). Tends to be decomposed and the yield tends to decrease. In addition, in the case of such heating, it is preferable to heat the said 2nd liquid mixture, stirring from a viewpoint of dissolving a product more efficiently in a short time.

  Moreover, it is preferable that content of the compound represented by the said General formula (2) in said 2nd liquid mixture in such a hot filtration process is 5-30 mass%. If the content of such a compound is less than the lower limit, a large amount of solvent is required, and thus production efficiency tends to decrease. On the other hand, if the upper limit is exceeded, the compound represented by the general formula (2) is sufficient. There is a tendency not to dissolve.

  Moreover, in the said hot filtration process, it filters, after heating said 2nd liquid mixture. Thereby, metal residues, such as a palladium catalyst and an oxidizing agent, can be easily separated from the second mixed solution. This is because such a palladium catalyst and an oxidizing agent are basically components that are not dissolved in the aromatic hydrocarbon in the temperature range, and therefore exist as a solid content in the second mixed solution. In addition, such a filtration method is not particularly limited, and a known method can be appropriately employed. For example, a vacuum filtration using a Kiriyama funnel or a filtration using a pressure filter may be employed. . In such filtration, it is preferable to employ a method of filtration while maintaining the temperature of the second mixed solution in the temperature range of the heating temperature.

  In this way, by using the filtrate obtained after separation of the palladium catalyst and the oxidant by filtration, it is possible to efficiently remove metal residues by removing the reaction product by purification. It becomes possible to obtain a highly pure compound more efficiently. In such a hot filtration step, a washing step may be further performed on the filtrate after filtration. By such a washing process, the metal residue (Pd, Cu) of the palladium catalyst and the oxidizing agent tends to be more sufficiently separated from the reaction product. Such a washing step is not particularly limited, and a known method can be appropriately employed. For example, washing using hydrochloric acid or saturated sodium bicarbonate may be appropriately performed. In the filtrate washing step, it is preferable to maintain the temperature of the filtrate within the temperature range of the heating temperature in the hot filtration step.

  Moreover, the said refinement | purification process should just be a process refine | purified after replacing the alcohol in the liquid mixture (reaction liquid mixture) after the said reaction by the said C9-C9 aromatic hydrocarbon, and it does not restrict | limit in particular. However, since the purification step can be carried out in a series of steps and becomes an industrially more advantageous method, the filtrate obtained after the hot filtration step (solvent: fragrance having 6 to 9 carbon atoms). It is more preferable to purify using a group hydrocarbon.

  Moreover, as a purification process after substituting the alcohol in the mixed liquid (reaction mixed liquid) after such reaction with the aromatic hydrocarbon having 6 to 9 carbon atoms, a reaction product from the reaction mixed liquid is used. (For example, the reaction product may be obtained by distilling off the solvent from the filtrate after the hot filtration step), and again the reaction product and the fragrance having 6 to 9 carbon atoms. It may be a step of preparing a mixed solution containing a group hydrocarbon and purifying using the mixed solution.

  In addition, the crystallization method that can be suitably used in the purification step is not particularly limited, but the alcohol in the mixed solution after the reaction is converted into the aromatic hydrocarbon having 6 to 9 carbon atoms. After the substitution, it is preferable to employ a method in which the product is dissolved in the aromatic hydrocarbon by heating to 40 to 150 ° C. and then allowed to cool to precipitate crystals, which is obtained after the hot filtration step. It is more preferable to employ a method of using a filtrate and allowing the filtrate to cool and precipitate crystals. In the case of using the filtrate obtained after such a hot filtration step, it is more preferable to concentrate the filtrate appropriately so that the crystals are more likely to precipitate, and then to cool to precipitate the crystals. In addition, when using the filtrate obtained after such a hot filtration step, purification can be performed in a series of steps, and thus a product with higher purity can be obtained more easily. Become.

  In addition, as another method in the case of using a crystallization method for purification, for example, the alcohol in the mixed solution after the reaction is replaced with an aromatic hydrocarbon having 6 to 9 carbon atoms, vacuum dried and solidified. After the content is obtained, the obtained solid content is again dissolved in the aromatic hydrocarbon having 6 to 9 carbon atoms, and then the temperature is lower than the dissolution temperature of the compound represented by the general formula (2). A method of recrystallization (recrystallization method) may be employed. As such a recrystallization method, the filtrate obtained after the hot filtration step is used, and the filtrate is vacuum-dried to obtain a solid content, and then the obtained solid content has 6 to 9 carbon atoms. It is more preferable to employ a method of recrystallization after dissolving again in the aromatic hydrocarbon and lowering the temperature below the melting temperature. In addition, also as a solvent utilized for such a recrystallization method, it is necessary to use the said C6-C9 aromatic hydrocarbon from a viewpoint that the recovery rate of a product and the efficiency of a by-product removal improve more. There is.

  Moreover, in such a recrystallization method, it is preferable that the temperature conditions at the time of melt | dissolving the said solid content are -40 degreeC-200 degreeC, and it is more preferable that it is 0-150 degreeC. When such temperature exceeds the upper limit, the compound represented by the general formula (2) tends to be decomposed and the yield tends to decrease. On the other hand, when the temperature is lower than the lower limit, the general formula (2 ) Tends to not be sufficiently dissolved in the solvent. When the solid content is dissolved in this way, a refluxing step may be performed.

  Moreover, the amount of the aromatic hydrocarbon having 6 to 9 carbon atoms when such a crystallization method (including recrystallization method) is employed is based on the compound represented by the general formula (2). It is preferably 0.5 to 500 times (V / V) based on the capacity, and more preferably 1 to 100 times (V / V). When the amount (magnification) of the aromatic hydrocarbon having 6 to 9 carbon atoms is less than the lower limit, the compound represented by the general formula (2) tends not to be sufficiently dissolved in the solvent. When the upper limit is exceeded, precipitation of the compound represented by the general formula (2) becomes insufficient and the yield tends to decrease.

  Furthermore, the amount of the aromatic hydrocarbon having 6 to 9 carbon atoms when such a crystallization method (including a recrystallization method) is employed is such that the concentration of the compound represented by the general formula (2) is It is preferably 5 to 30% by mass, and more preferably 10 to 30% by mass. If the concentration of such a compound is less than the lower limit, a large amount of solvent is required, and thus production efficiency tends to decrease. On the other hand, if the upper limit is exceeded, the compound represented by the general formula (2) is sufficiently dissolved. There is a tendency not to.

  Moreover, as an adsorption separation method that can be suitably used for the purification step, for example, a known adsorption agent such as adsorbent addition, column chromatography, HPLC, filtration, solid-liquid extraction and the like is appropriately used. By adopting means, a method of selectively separating the compound represented by the general formula (2) or the like can be employed. When filtration using an adsorbent is used, for example, the alcohol in the mixed solution after the reaction is replaced with an aromatic hydrocarbon having 6 to 9 carbon atoms, and then heated to 40 to 150 ° C. for the fragrance. After the product is dissolved in the aromatic hydrocarbon, an adsorbent is added to separate impurities, and a vacuum (preferably about 10 to 1000 Pa) is applied to evaporate the aromatic hydrocarbon, whereby the general formula ( You may employ | adopt the method of refine | purifying the compound represented by 2). Among such adsorptive separation methods, after using the filtrate obtained after carrying out the hot filtration step, after adding an adsorbent to the filtrate and adsorbing and separating impurities (byproducts, etc.), It is more preferable to employ a method for purifying the compound represented by the general formula (2) by evaporating the aromatic hydrocarbon under vacuum (preferably about 10 to 1000 Pa).

  The adsorbent that can be used in such an adsorption separation method is not particularly limited, and examples thereof include celite, silica gel, activated alumina, activated clay, silica alumina, zeolite, activated carbon, carbon nanotube, charcoal, and ion exchange resin. Among these adsorbents, activated alumina, activated clay, and activated carbon are more preferable, and activated alumina and activated clay are more preferable because the content of by-products can be suppressed to a higher degree.

  Moreover, the addition amount of the adsorbent in such an adsorption separation method is not particularly limited, but is 1 to 20 parts by mass (more preferably 3 to 10 parts by mass) with respect to 100 parts by mass of the compound represented by the general formula (2). Part). If the amount of adsorbent added is less than the above lower limit, the by-product adsorbing and removing tends not to be sufficiently performed. is there.

  Moreover, it is preferable that the temperature conditions at the time of isolate | separating the compound represented by the said General formula (2) by such an adsorption separation method are -40 degreeC-200 degreeC, and it is more preferable that it is 0-100 degreeC. preferable. When such temperature exceeds the upper limit, the compound represented by the general formula (2) is decomposed, and the compound represented by the general formula (2) tends to be unable to be obtained efficiently. On the other hand, if it is less than the lower limit, the compound represented by the general formula (2) tends not to be sufficiently dissolved in the solvent.

  Further, the amount of the aromatic hydrocarbon having 6 to 9 carbon atoms when such an adsorption separation method is adopted is 0.5% based on the capacity of the compound represented by the general formula (2). It is preferably ˜500 times (V / V), more preferably 2 to 100 times (V / V). When the amount (magnification) of the aromatic hydrocarbon having 6 to 9 carbon atoms is less than the lower limit, the compound represented by the general formula (2) tends not to be sufficiently dissolved in the solvent. When the upper limit is exceeded, a dilute solution of the compound represented by the general formula (2) is obtained, and the working efficiency and the recovery rate tend to decrease.

  Furthermore, when using such an adsorption separation method, the amount of the aromatic hydrocarbon having 6 to 9 carbon atoms is such that the concentration of the compound represented by the general formula (2) is 5 to 30% by mass. It is preferable to do so. If the concentration of such a compound is less than the lower limit, a large amount of solvent is required, and thus production efficiency tends to decrease. On the other hand, if the upper limit is exceeded, the compound represented by the general formula (2) is sufficiently dissolved. There is a tendency not to.

  In this way, by performing a purification step according to the type of the target compound, it becomes possible to more sufficiently reduce the content of by-products (particularly polymer) in the separated compound. It is also possible to obtain a compound represented by the general formula (2) with less coloring.

  According to the present invention, the content of the by-product can be suppressed at a higher level, and the compound represented by the general formula (2) having higher purity can be obtained. Therefore, according to the present invention, norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6, which is more suppressed in color (hue is further improved). , 6 ″ -tetracarboxylic acid and esters thereof, and norbornane-2-spiro-α-cycloalkanone-α ′ in which coloring is further suppressed (hue is further improved) using such a compound as a raw material -Since spiro-2 "-norbornane-5,5", 6,6 "-tetracarboxylic dianhydrides can be obtained, the present invention produces a more transparent polyimide. It is particularly useful as a method for producing a raw material compound for the purpose.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example.

In addition, identification of the molecular structure of the compound obtained in each Example etc. is performed by IR measuring machine (trade name: FT / IR-460, FT / IR-4100 manufactured by JASCO Corporation) and NMR measuring machine (Varian). Product name: UNITY INOVA-600 and JEOL Ltd. JNM-Lambda500) were used to measure IR spectrum and NMR spectrum, respectively. Moreover, the ratio of the polymer in a product is a gel permeation chromatography measuring apparatus (GPC, the Tosoh Corporation make, brand name: HLC-8020 / four columns: Tosoh Corporation make, brand name: TSK gel GMH _HR. , Solvent: tetrahydrofuran (THF)).

Example 1
In a container of 1000 mL glass autoclave (trade name “Hyperblaster TEM-V type” manufactured by pressure-resistant glass industry), methanol (820 mL), CuCl ₂ (II) (81.6 g, 454 mmol), the following general formula (6 ):

5-norbornene-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -5 ″ -norbornene (35.6 g, 148 mmol: hereinafter sometimes referred to as “raw material compound”. ) And Pd ₃ (OAc) ₅ (NO ₂ ) (166 mg, 0.74 mmol in terms of Pd) were added to obtain a mixed solution. Pd ₃ (OAc) ₅ (NO ₂ ) was produced by adopting the method described on page 1991 of Dalton Trans (vol. 11) issued in 2005. Further, the norbornene compound represented by the general formula (6) was produced by employing the same method as that disclosed in Synthesis Example 1 of International Publication No. 2011/099518.

  Subsequently, the glass tube was arrange | positioned so that gas could be bubbled through the glass tube with respect to the liquid mixture which exists in the inside of the said container. Then, the said container was sealed and internal atmospheric gas was substituted with nitrogen. Thereafter, a vacuum pump was connected to the container to reduce the pressure in the container (pressure in the container: 0.015 MPa). Next, while supplying carbon monoxide through the glass tube at a rate (flow rate) of 0.015 molar equivalent / minute with respect to the raw material compound, the temperature is adjusted to 25 to 30 ° C. While maintaining the pressure in the container at 0.13 MPa, the mixture was stirred for 5 hours, and then the pressure in the container was further reduced to 0.13 MPa under the condition of temperature: 40 ° C. The mixture was stirred for 3 hours so as to maintain the reaction solution. Next, the atmosphere gas containing carbon monoxide was removed from the inside of the vessel, and the reaction solution was concentrated with an evaporator to remove (evaporate) methanol from the reaction solution to obtain a reaction product (yield) 65.4 g, yield 92.6%, polymer 2.20%: The yield and yield were determined by measuring the reaction product by high performance liquid chromatography (HPLC, 1200 series, manufactured by Agilent). And the ratio of the polymer is a value obtained by measurement by GPC analysis).

Thereafter, the reaction product is transferred to another container (glass container with a capacity of 2000 mL), and toluene (1200 mL) is added to the reaction product and stirred vigorously at 80 ° C. for 1 hour. As a result, the reaction product was extracted with toluene to obtain a toluene extract (concentration of reaction product: 8.4% by mass). Next, CuCl and Pd ₃ (OAc) ₅ (NO ₂ ) not dissolved in toluene were separated from the toluene extract by vacuum filtration using a Kiriyama funnel while maintaining the temperature of the toluene extract at 80 ° C. .

Next, the toluene extract (filtrate) after separating CuCl and Pd ₃ (OAc) ₅ (NO ₂ ) in this way was subjected to twice with 5% by mass hydrochloric acid (400 ml) at a temperature of 80 ° C. Washed. Subsequently, the toluene extract thus washed with hydrochloric acid was washed once with a saturated aqueous sodium hydrogen carbonate solution (400 ml) under the temperature condition of 80 ° C. Next, the toluene extract obtained after washing is filtered through a filter, and the toluene extract (hereinafter, the toluene extract obtained after the filter filtration is referred to as “toluene extract (A)” in some cases). Obtained. The concentration of the reaction product in the toluene extract (A) was 7.9% by mass, and the total amount was 852 g. Next, the filtered toluene extract (A) was concentrated by heating to about 110 ° C., which is the boiling point of toluene, at normal pressure (0.1 MPa). By such a concentration operation, 900 ml of toluene in a total amount was distilled off to obtain a concentrated liquid (concentrated liquid of the toluene extract) in which the concentration of the reaction product was adjusted to 20% by mass. Thereafter, the concentrated solution was allowed to cool at room temperature (25 ° C.) for about 12 hours to precipitate white crystals. Next, white crystals are filtered off from the concentrated solution, washed twice with 50 mL of toluene, and subjected to a step of vacuum drying at 60 ° C. to the obtained white crystals to adhere to the crystals. The toluene was evaporated to give the product (white crystals, 33.9 g, 48% yield).

In order to confirm the structure of the product thus obtained, IR measurement and NMR ( ¹ H-NMR) measurement were performed. The IR spectrum of the product thus obtained is shown in FIG. 1, and the ¹ H-NMR (CDCl ₃ ) spectrum is shown in FIG. As is apparent from the results shown in FIGS. 1 and 2, the obtained product has the following general formula (7):

(Norbornane-2-spiro-α-cyclopentanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid tetramethyl ester) confirmed. Further, when GPC analysis was performed on the obtained product, a polymer which is an impurity (a polymer obtained by addition polymerization of norbornene rings in the raw material compound or a polymer obtained by bonding a plurality of norbornene rings with keto groups) The content of the mixture was 0.52%. The obtained product was dissolved in N, N-dimethylacetamide to prepare a 5 mass% solution, and a UV-Vis measuring device (trade name “UV-2550”) manufactured by Shimadzu Corporation was used as a measuring device. When the transmittance of light at 400 nm was measured using, the transmittance of light at 400 nm was 98.0%.

(Example 2)
First, a method similar to the method employed in Example 1 was employed to produce a toluene extract (A) in which the concentration of the reaction product in the toluene extract was 7.9% by mass. Next, 30 g of the toluene extract (A) was taken out, and then 0.12 g of activated alumina (Union Showa, trade name “Activated Alumina V−”) was adsorbed to the 30 g of toluene extract (A). (GL25 ") was added (addition amount of adsorbent: 5 parts by mass with respect to 100 parts by mass of the reaction product), and the mixture was allowed to stand at 60 ° C for 3 hours. Next, while maintaining the temperature condition of 60 ° C., the activated alumina was separated by filtration to obtain a filtrate. Next, the obtained filtrate was concentrated with an evaporator and vacuum-dried (1 Torr) at 80 ° C. to obtain a product (white crystals, 2.13 g).

In order to confirm the structure of the product thus obtained, IR measurement and NMR ( ¹ H-NMR) measurement were performed. The obtained product was a compound represented by the above general formula (7). there were. The amount of product obtained after use of the adsorbent (ratio of the compound that can be recovered after use of the adsorbent [recovery] with respect to the total amount of product in 30 g of toluene extract (A) before addition of activated alumina. The rate]) was found to be 90%. Moreover, when the content of the polymer was measured for the obtained product by GPC analysis, the polymer which is an impurity was not detected. Furthermore, the obtained product was dissolved in N, N-dimethylacetamide to prepare a 5 mass% solution, and a UV-Vis measuring device (trade name “UV-2550”) manufactured by Shimadzu Corporation was used as a measuring device. When the transmittance of light at 400 nm was measured using, the transmittance of light at 400 nm was 90.0%.

(Examples 3 to 8)
Instead of adding 0.12 g (5 parts by mass with respect to 100 parts by mass of the reaction product) of activated alumina to 30 g of toluene extract (A), the table was added to 30 g of toluene extract (A). A product (white crystals) was obtained in the same manner as in Example 2 except that the adsorbent described in 1 was added in the addition amount described in Table 1 (amount based on 100 parts by mass of the reaction product). . In addition, as a result of confirming the structure of each product in the same manner as in Example 2, it was confirmed that each product was a compound represented by the above general formula (7). In addition, the obtained product was measured for the content of the polymer by GPC analysis and the light transmittance at 400 nm in the same manner as in Example 2. The obtained results (polymer content and transmittance) are shown in Table 1.

(Comparative Example 1)
First, a method similar to the method employed in Example 1 was employed to produce a toluene extract (A) in which the concentration of the reaction product in the toluene extract was 7.9% by mass. Subsequently, the total amount (852 g) of the toluene extract (A) was concentrated by an evaporator and vacuum-dried (1 Torr) for 12 hours under the condition of 80 ° C., thereby obtaining a product (gray solid, 65.4 g, yield 92.6). %). In order to confirm the structure of the product thus obtained, IR measurement and NMR ( ¹ H-NMR) measurement were carried out. As a result, the obtained product was obtained from the compound represented by the general formula (7). Contained. In addition, the obtained product was measured for the content of the polymer by GPC analysis and the light transmittance at 400 nm in the same manner as in Example 2. The obtained results (polymer content and transmittance) are shown in Table 1.

Although not an example using an adsorbent, Table 1 also shows the results of the content of the polymer in the product obtained in Example 1 and the light transmittance at 400 nm. Moreover, as activated alumina, activated clay V1, and activated clay NS in Table 1, those shown in the following (1) to (3) were used.
(1) Activated alumina: Union Showa, trade name “Activated Alumina V-GL25”
(2) Activated clay V1: Made by Mizusawa Chemical Co., Ltd., trade name “Galleon Earth V1”
(3) Activated clay NS: Made by Mizusawa Chemical Co., Ltd., trade name “Galleon Earth NS”

Example 9
First, a method similar to that employed in Example 1 was employed to produce a toluene extract (A) having a reaction product concentration of 7.9% by mass in the toluene extract. Next, the whole amount (852 g) of the toluene extract (A) was concentrated with an evaporator and vacuum-dried (1 Torr) for 12 hours under the condition of 80 ° C. to obtain a gray solid (65.4 g, yield 92.6%). Obtained. In addition, when the measurement of the content of the polymer by GPC analysis and the measurement of the light transmittance of 400 nm were performed on the obtained gray solid in the same manner as in Example 2, the content of the polymer was 2. The transmittance of light at 400 nm was 49.1%.

  The gray solid thus obtained (5 g) was added to toluene, heated to 11 ° C. (reflux temperature) under a nitrogen atmosphere and refluxed to dissolve the gray solid in toluene. A toluene solution having a concentration of 20% by mass was obtained. After the toluene solution was obtained in this way, the toluene solution was naturally cooled and allowed to stand at room temperature (25 ° C.) for 12 hours to precipitate crystals in the toluene solution, and the crystals were filtered out. Thereafter, toluene attached to the obtained crystal was evaporated to obtain a product (white crystal) (recrystallization method).

  As a result of confirming the structure of the product in the same manner as in Example 2, it was confirmed that the product was a compound represented by the above general formula (7). In addition, the obtained product was measured for the content of the polymer by GPC analysis and the light transmittance at 400 nm in the same manner as in Example 2. Furthermore, the ratio (recovery rate) of the amount of product recovered with respect to the total amount of gray solid (5 g) used in the recrystallization method was determined. The obtained results are shown in Table 2.

(Examples 10 to 12)
The recrystallization method was carried out except that instead of using a toluene solution having a gray solid concentration of 20% by mass, a toluene solution having a gray solid concentration (5 g) as shown in Table 2 was used. In the same manner as in Example 9, the product (white crystals) was obtained by the recrystallization method. In addition, as a result of confirming the structure of each product in the same manner as in Example 2, it was confirmed that each product was a compound represented by the above general formula (7). In addition, the obtained product was measured for the content of the polymer by GPC analysis and the light transmittance at 400 nm in the same manner as in Example 2. Furthermore, the ratio (recovery rate) of the amount of product recovered with respect to the total amount of gray solid (5 g) used in the recrystallization method was determined. The obtained results are shown in Table 2.

  As is clear from the results shown in Tables 1 and 2, in the case where the alcohol in the reaction mixture was purified after being substituted with an aromatic hydrocarbon having 6 to 9 carbon atoms (Examples 1 to 12), Compared to the case where the purification process is not carried out (Comparative Example 1), it is confirmed that the amount of the polymer (by-product) is sufficiently reduced and the content of the by-product can be suppressed at a higher level. It was done. Thus, in the present invention (Examples 1 to 12), the content of by-products has been sufficiently reduced, and the transmittance when dissolved in a solvent has become higher, It was also confirmed that the obtained product was further reduced in coloring. From these results, the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid of the present invention and its ester It can be seen that this kind of production method is also useful as a method for producing a raw material compound for producing a highly transparent polyimide.

  As described above, according to the present invention, norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane- in which the content of by-products is reduced to a higher level Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5 which makes it possible to obtain 5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof , 5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof can be provided.

  Therefore, the process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof of the present invention Is a polyimide for flexible wiring boards that require heat resistance, a polyimide for heat-resistant insulating tape, a polyimide for wire enamel, a polyimide for semiconductor protective coating, a polyimide for liquid crystal alignment film, and a transparent electrode substrate for organic EL Polyimide for solar cell transparent electrode substrate, polyimide for electronic paper transparent electrode substrate, various gas barrier film substrate materials, polyimide for interlayer insulation film, polyimide for sensor substrate, polyimide for printer transfer belt, etc. It is particularly useful as a method for producing a raw material compound for producing the.

Claims (5)

The following general formula (1):
[In the formula (1), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and n is 0. An integer of ~ 12 is shown. ]
-Norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornenes represented by the formula: a mixed solution containing an alcohol, a palladium catalyst, and an oxidizing agent By supplying carbon monoxide into the 5-norbornene-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -5 ″ -norbornene with the alcohol and the carbon monoxide. The following general formula (2):
[In the formula (2), R ¹ , R ² and R ³ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 10 carbon atoms and a fluorine atom, and R ⁴ , R ⁵ , R ⁶ and R ⁷ are each independently a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an alkenyl group having 2 to 10 carbon atoms, or 6 to 20 carbon atoms. 1 type selected from the group consisting of an aryl group and an aralkyl group having 7 to 20 carbon atoms, and n represents an integer of 0 to 12. ]
A norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof represented by: A reaction mixture containing the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof; Obtaining a step;
By purifying the alcohol in the reaction mixture after substitution with an aromatic hydrocarbon having 6 to 9 carbon atoms, the norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″- Obtaining norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof;
Of norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and its esters, characterized in that Production method.   2. The purification method according to claim 1, wherein the purification method is a method of purifying by crystallization after substituting the alcohol in the reaction mixture with an aromatic hydrocarbon having 6 to 9 carbon atoms. Of norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof.   The purification method is characterized in that after the alcohol in the reaction mixture is substituted with an aromatic hydrocarbon having 6 to 9 carbon atoms, the purification is performed by an adsorption separation method using an adsorbent. Process for producing norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic acid and esters thereof according to Item 1 .   The norbornane-2-spiro-α-cycloalkanone-α according to claim 3, wherein the adsorbent is at least one selected from the group consisting of activated alumina, activated clay and activated carbon. A process for producing '-spiro-2' '-norbornane-5,5' ', 6,6' '-tetracarboxylic acid and esters thereof.   The aromatic hydrocarbon having 6 to 9 carbon atoms is at least one selected from the group consisting of toluene, xylene, ethylbenzene, 1,3,5-trimethylbenzene and isopropylbenzene. Norbornane-2-spiro-α-cycloalkanone-α′-spiro-2 ″ -norbornane-5,5 ″, 6,6 ″ -tetracarboxylic according to any one of 1 to 4 A method for producing acids and esters thereof.