WO2025197812A1 - Method for producing metal salt of alicyclic dicarboxylic acid - Google Patents

Abstract

A method for producing a metal salt of an alicyclic dicarboxylic acid (a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt of an alkyl-substituted 1,2-dicarboxylic acid) is provided, the method making it possible to reduce discard loss, being simple, and having excellent selectivity (molar ratio of a cis-isomer).　The method for producing a metal salt of an alicyclic dicarboxylic acid is characterized in that the alicyclic dicarboxylic acid is a metal salt of a cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly bonded to the cyclohexane ring, the alkyl substituent being a C1-C4 linear or branched alkyl group, that the metal salt is a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt, and that the method includes steps (1) and (2).

Description

Method for producing metal salts of alicyclic dicarboxylic acids

The present invention relates to a method for producing a metal salt of an alicyclic dicarboxylic acid.

The inventors have been developing metal salts of various carboxylic acids as crystal nucleating agents for crystalline thermoplastic resins. As a result, it has become clear that metal salts of alkyl-substituted cyclohexane-1,2-dicarboxylic acids exhibit excellent nucleating agent performance in resins such as polyolefins.

Furthermore, the present inventors have conducted a detailed study on the influence of the structure of a metal salt of an alkyl-substituted cyclohexane-1,2-dicarboxylic acid on its nucleating agent performance, and as a result have confirmed that excellent nucleating agent performance is exhibited when the metal species forming the metal salt is calcium or sodium.
They also found that the steric structure of the oxycarbonyl group that forms a metal salt with an alkyl substituent located via a cyclohexane ring has a significant effect, and ultimately found that the nucleating agent performance is excellent in correlation with the molar ratio of the cis isomer (see Patent Document 1).

International Publication No. 2020/054492

Generally, the metal salts of the alkyl-substituted cyclohexane-1,2-dicarboxylic acids are produced through the following steps (1) to (3).
(1) A conjugated diene compound and maleic anhydride are subjected to a Diels-Alder reaction to obtain an alkyl-substituted 4-cyclohexene-1,2-dicarboxylic anhydride. Alternatively, an alkyl-substituted phthalic anhydride is obtained by adding an alkyl substituent to phthalic anhydride.
(2) Alkyl-substituted 4-cyclohexene-1,2-dicarboxylic anhydride or alkyl-substituted phthalic anhydride is hydrogenated to obtain alkyl-substituted cyclohexane-1,2-dicarboxylic anhydride.
(3) Reacting an alkyl-substituted cyclohexane-1,2-dicarboxylic anhydride with an oxide, hydroxide, or chloride of a metal species that forms the desired metal salt.

In the above reaction system, the steric structure of the alkyl substituents positioned via the cyclohexane ring, which significantly influence the aforementioned nucleating agent performance, and the oxycarbonyl group that forms the metal salt, is a molar ratio of cis/trans isomers. When alkyl-substituted phthalic anhydride is used as the raw material for the hydrogenation reaction, the above molar ratio is determined during the hydrogenation reaction (step (2) above).

When a hydrogenation reaction is performed using alkyl-substituted 4-cyclohexene-1,2-dicarboxylic anhydride, the molar ratio of the isomers of the alkyl substituents at the 3- and 6-positions is determined during the Diels-Alder reaction and the hydrogenation reaction. Furthermore, the molar ratio of the isomers of the alkyl substituents at the 4- and 5-positions is determined during the hydrogenation reaction. In other words, the cis/trans isomer ratio is already determined before conversion to a metal salt (before step (3) above).

In both the Diels-Alder reaction and the hydrogenation reaction, the production of the cis isomer is stereochemically predominant, and even under typical reaction conditions, it is possible to obtain alkyl-substituted cyclohexane-1,2-dicarboxylic acids with a molar ratio of cis isomer of 60-70% or more. Furthermore, by devising the reaction conditions, it has been confirmed that alkyl-substituted cyclohexane-1,2-dicarboxylic acids with a molar ratio of cis isomer of nearly 100% can be obtained in the reaction system.

However, the double bond of the alkyl-substituted 4-cyclohexene-1,2-dicarboxylic anhydride used as the raw material easily migrates when exposed to heat or other factors (for example, this is likely to occur during step (2) (hydrogenation reaction) in conventional methods), resulting in the formation of impurities (ring structure isomers such as the Δ1 type) and a decrease in selectivity. As a result, the molar ratio of cis isomers at the end of the reaction is usually limited to around 85%, and it is difficult to reach 90% even under special conditions using large amounts of solvent, etc.

Furthermore, because the relative volatility of the cis- and trans-isomers of alkyl-substituted cyclohexane-1,2-dicarboxylic acids is similar, removing the trans-isomer requires more than 100 theoretical plates. This poses problems such as the need for a large amount of heat and high waste losses due to low recovery rates.

The present invention aims to provide a method for producing metal salts of alicyclic dicarboxylic acids (calcium salts, hydroxyaluminum salts, disodium salts, or dilithium salts of alkyl-substituted 1,2-dicarboxylic acids) that reduces waste, is simple, and has excellent selectivity (molar ratio of cis isomers).

As a result of extensive research conducted by the present inventors to solve the above problems, they discovered that all of the above problems can be solved by using a method for producing a metal salt of an alicyclic dicarboxylic acid, which includes step (1) of obtaining an alkali metal salt or ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms as a raw material, and step (2) of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in step (1), thereby completing the present invention.

That is, the present invention provides a method for producing a metal salt of an alicyclic dicarboxylic acid, wherein the alicyclic dicarboxylic acid is a metal salt of cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly bonded to the cyclohexane ring, the alkyl substituent being a linear or branched alkyl group having 1 to 4 carbon atoms, and the metal salt is a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt, and the method comprises the following steps (1) and (2):
Step (1): A step of obtaining an alkali metal salt or an ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms as a raw material. Step (2): A step of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in the above step (1).

In the method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention, the alkali metal salt in step (1) is preferably at least one selected from the group consisting of sodium salts, potassium salts, and lithium salts.
It is more preferable that the alkali metal salt in step (1) above is a sodium salt.
The catalyst for the hydrogenation reaction in the step (2) is preferably at least one selected from the group consisting of palladium, rhodium, and ruthenium.
In addition, the temperature of the hydrogenation reaction in the step (2) is preferably 80° C. or lower.
It is also preferable to further include the following step (3).
Step (3): A step of converting the hydrogenated alkali metal salt or ammonium salt obtained in the above step (2) into a calcium salt or a disodium salt. It is also preferable to further include the following step (4) after the above step (2).
Step (4): A step of crystallizing the hydrogenated alkali metal salt or ammonium salt obtained in the step (2). The alkali metal salt crystallized in the step (4) is preferably a monoalkali metal salt.
The alkyl substituent is preferably located at the 3rd or 4th position of the cyclohexane ring.
The alkyl substituent is preferably a methyl group.
Furthermore, among the stereoisomers of the alkyl substituent via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt, the molar ratio of cis isomers is preferably 90.0% or more, more preferably 93.0% or more, and even more preferably 95% or more.

The present invention provides a method for producing metal salts of alicyclic dicarboxylic acids (calcium salts, hydroxyaluminum salts, disodium salts, or dilithium salts of alkyl-substituted 1,2-dicarboxylic acids) that is simple, reduces waste, and has excellent selectivity (molar ratio of cis isomers).

The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention is characterized in that the alicyclic dicarboxylic acid is a metal salt of cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly bonded to the cyclohexane ring, the alkyl substituent being a linear or branched alkyl group having 1 to 4 carbon atoms, and the metal salt is a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt, and the method comprises the following steps (1) and (2):
Step (1): A step of obtaining an alkali metal salt or an ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms as a raw material. Step (2): A step of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in the above step (1).

The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention includes the above-mentioned steps (1) and (2), and thereby makes it possible to obtain the target metal salt of an alicyclic dicarboxylic acid having a high molar ratio of cis isomer (calcium salt, hydroxyaluminum salt, disodium salt, or dilithium salt of an alkyl-substituted 1,2-dicarboxylic acid) in high yield.
Furthermore, since the purification process (distillation process, etc.) can be omitted, waste can be reduced.

In addition, the "cis isomer" of the calcium salt, hydroxyaluminum salt, disodium salt, or dilithium salt of alkyl-substituted 1,2-dicarboxylic acid means that the alkyl substituent on the cyclohexane ring and the two oxycarbonyl groups that make up the metal salt all point in the same direction.

Each process is explained below.

<Step (1)>
The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention includes the following step (1):
Step (1): A step of obtaining an alkali metal salt or an ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent having 1 to 4 carbon atoms (also referred to as alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride) or phthalic anhydride having a linear or branched alkyl substituent having 1 to 4 carbon atoms (also referred to as alkyl-substituted phthalic anhydride) as a raw material.

The alkyl-substituted cyclohexene-1,2-dicarboxylic acid anhydride preferably has a linear or branched alkyl substituent having 1 to 4 carbon atoms at the 3rd or 4th position, more preferably at the 4th position.

In the alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride, examples of the linear or branched alkyl substituent having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
Among these, a methyl group or a tert-butyl group is preferred from the viewpoint of the crystallization promoting effect when the resulting metal salt of an alicyclic dicarboxylic acid is used as a crystal nucleating agent.

The alkyl-substituted phthalic anhydride preferably has a linear or branched alkyl substituent having 1 to 4 carbon atoms at the 3rd or 4th position, more preferably at the 4th position.

In the alkyl-substituted phthalic anhydride, examples of the linear or branched alkyl substituent having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
Among these, a methyl group or a tert-butyl group is preferred from the viewpoint of the crystallization promoting effect when the resulting metal salt of an alicyclic dicarboxylic acid is used as a crystal nucleating agent.

The alkali metal salt or ammonium salt obtained in step (1) above can be obtained by reacting the alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride or the alkyl-substituted phthalic anhydride with an alkali metal hydroxide or an amine to open the acid anhydride ring.

Examples of the alkali metal hydroxides include hydroxides of sodium, potassium, lithium, etc.

Examples of the above amines include triethylamine, ammonia, trimethylamine, etc.

The amount of the alkali metal hydroxide or amine used is preferably 1 to 2 equivalents, and more preferably 1.1 to 1.9 equivalents, relative to the alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride or alkyl-substituted phthalic anhydride, from the viewpoint of stereoselectivity.

The alkali metal salt or ammonium salt obtained in step (1) above is preferably at least one selected from sodium salt, potassium salt, and lithium salt, more preferably sodium salt or potassium salt, and even more preferably sodium salt.

In the above step (1), the reaction method and reaction conditions are not particularly limited as long as an alkali metal salt or an ammonium salt is obtained.
In a general method, the alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride or the alkyl-substituted phthalic anhydride can be easily obtained by adding the alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride or the alkyl-substituted phthalic anhydride to a solution prepared by dissolving the alkali metal hydroxide or amine in water, and stirring the mixture at room temperature or under slight heating.

By undergoing the above step (1), when general-purpose water is used in the next step (2), it is possible to make the reaction system homogeneous from the initial stage of the reaction. This effect is particularly remarkable when the reaction temperature is lowered to increase the molar ratio of the cis isomer.
Therefore, by including the above step (1), it is not necessary to use a special solvent, and it is possible to simplify the production and reduce costs.

<Step (2)>
The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention includes the following step (2):
Step (2): A step of hydrogenating the alkali metal salt or ammonium salt obtained in step (1) above.

The hydrogenation reaction in step (2) above is preferably carried out under the following conditions:

(a) Concentration In the step (2) above, a solution of the alkali metal salt or ammonium salt (also referred to as the substrate) obtained in the step (1) above is used.
The concentration of the substrate is not particularly limited, but is preferably 1% by mass or more and 25% by mass or less, and more preferably 5% by mass or more and 20% by mass or less.

(b) Reaction Catalyst As the reaction catalyst, palladium, ruthenium and rhodium are preferred from the viewpoint of increasing the molar ratio of the resulting cis isomer.
Furthermore, a more preferable reaction catalyst is selected depending on the position or type of alkyl substituent in the alkali metal salt or ammonium salt obtained in the above step (1) or the type of acid anhydride. For example, when the above alkyl-substituted cyclohexene-1,2-dicarboxylic anhydride is used, palladium and ruthenium are preferred, and when the alkyl-substituted phthalic anhydride is used, rhodium and ruthenium are preferred.

The reaction catalyst may be supported on a carrier such as carbon, alumina, silica, zirconia, or zeolite.
In this case, the amount of support is preferably 0.1 to 10% by mass.

The amount of reaction catalyst used is preferably 0.1 to 5 parts by mass per 100 parts by mass of the alkali metal salt or ammonium salt obtained in step (1) above.

(c) Reaction Temperature The reaction temperature is preferably 80° C. or lower from the viewpoint of suppressing the formation of the above-mentioned impurities (ring structure isomers such as Δ1 type) and the decrease in selectivity.
If the reaction temperature is 80° C. or lower, a metal salt of an alicyclic dicarboxylic acid having a molar ratio of cis isomer of 90.0% or higher can be suitably obtained.
The reaction temperature is more preferably 60° C. or lower.

(d) Reaction Pressure From the viewpoint of suppressing the generation of the above-mentioned impurities (ring structure isomers such as Δ1-type) and the decrease in selectivity, the reaction pressure is preferably 0.1 MPa or more, more preferably 0.9 MPa or more, still more preferably 1.8 MPa or more, and particularly preferably 4 MPa or more, in terms of hydrogen pressure (gauge pressure).
Furthermore, in consideration of the problem of the need for high-pressure gas equipment, the reaction pressure can be set to a hydrogen pressure (gauge pressure) of less than 1.0 MPa. By setting the hydrogen pressure (gauge pressure) to less than 1.0 MPa, industrially suitable production can be achieved.

(e) Reaction Time The reaction time is not particularly limited, but is preferably, for example, 30 minutes or more and 5 hours or less.
The reaction time means the time from when the reaction temperature is reached to when the reaction is completed.

(f) Reaction Solvent Water may be used as the solvent.

<Step (3)>
The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention preferably further includes the following step (3) as necessary.
Step (3): A step of converting the hydrogenated alkali metal salt or ammonium salt (also simply referred to as a hydrogenated compound) obtained in the above step (2) into a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt.

When the target metal salt of an alicyclic dicarboxylic acid is a disodium salt, if the alkali metal salt obtained in the above step (1) is a sodium salt, the disodium salt can be obtained by appropriately reacting the disodium salt with an aqueous sodium hydroxide solution after the above step (2), and the above step (3) can be omitted.
When the alkali metal salt obtained in the step (1) is other than a sodium salt, the hydrogenated compound obtained in the step (2) may be converted back to a carboxylic acid, and then reacted with an aqueous sodium hydroxide solution.

When the target metal salt of an alicyclic dicarboxylic acid is a dilithium salt, if the alkali metal salt obtained in the above step (1) is a lithium salt, the dilithium salt may be obtained by appropriately reacting the alkali metal salt with an aqueous lithium hydroxide solution after the above step (2), and the above step (3) may be omitted.
When the alkali metal salt obtained in the step (1) is other than a lithium salt, the hydrogenated compound obtained in the step (2) may be converted back to a carboxylic acid, and then reacted with an aqueous lithium hydroxide solution.

If the desired metal salt of an alicyclic dicarboxylic acid is a calcium salt or a hydroxyaluminum salt, it can be easily produced by a method such as the so-called metathesis method, in which the hydrogenated compound obtained in step (2) above is reacted with a hydroxide, oxide, chloride, etc. of calcium or hydroxyaluminum.

If a solvent is used in step (3) above, it is preferably water.

<Step (4)>
The method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention preferably further includes the following step (4) after the above step (2), as necessary.
Step (4): Crystallizing the hydrogenated compound obtained in step (2)

By including the step (4), the molar ratio of the cis isomer of the target metal salt of an alicyclic dicarboxylic acid can be suitably increased.
When the above step (3) is included, it is preferable to carry out step (4) before step (3).

In step (4) above, for example, the hydrogenated compound obtained in step (2) above can be dissolved in a solvent such as water under heating, and then cooled to crystallize the cis isomer. The solution of the hydrogenated compound obtained in step (2) above may also be used as is.

The alkali metal salt or ammonium salt crystallized in the above step (4) is preferably a monoalkali metal salt or a monoammonium salt from the viewpoint of solubility in water.
Specifically, the equivalent of the alkali metal salt or ammonium salt crystallized in the step (4) (the equivalent of the alkali metal salt (ammonium salt) relative to the alicyclic dicarboxylic acid) is preferably 1.0 to 1.3 equivalents.

The above step (4) is preferably carried out under the following conditions:

(a) Solvent The solvent is preferably one in which the cis isomer has a relatively low solubility and selectively precipitates the cis isomer, and in consideration of environmental aspects, water is more preferred.

(b) Concentration The concentration of the hydrogenated compound (also referred to as substrate concentration) during crystallization can be appropriately selected depending on the selectivity and yield of the cis isomer, but from the viewpoint of industrially suitable production, it is preferably 15 to 20 mass%.

<Metal Salt of Alicyclic Dicarboxylic Acid>
The metal salt of an alicyclic dicarboxylic acid produced by the method for producing a metal salt of an alicyclic dicarboxylic acid of the present invention will now be described.

The metal salt of the alicyclic dicarboxylic acid is a metal salt of cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly bonded to the cyclohexane ring, where the alkyl substituent is a linear or branched alkyl group having 1 to 4 carbon atoms, and the metal salt is a calcium salt, hydroxyaluminum salt, disodium salt, or dilithium salt.

Examples of the linear or branched alkyl group having 1 to 4 carbon atoms include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a sec-butyl group, and a tert-butyl group.
Among these, a methyl group or a tert-butyl group is preferred from the viewpoint of the crystallization-promoting effect when used as a crystal nucleating agent.

The position of the alkyl substituent is preferably the 3rd or 4th position of the cyclohexane ring, and more preferably the 4th position, from the viewpoint of the crystallization-promoting effect when used as a crystal nucleating agent.

The metal salt is preferably a calcium salt, from the viewpoint of its crystallization-promoting effect when used as a crystal nucleating agent.

Specific examples of the metal salts of the above alicyclic dicarboxylic acids include the disodium salt of 3-methylcyclohexane-1,2-dicarboxylic acid, the calcium salt of 3-methylcyclohexane-1,2-dicarboxylic acid, the hydroxyaluminum salt of 3-methylcyclohexane-1,2-dicarboxylic acid, the dilithium salt of 3-methylcyclohexane-1,2-dicarboxylic acid, the disodium salt of 3-ethylcyclohexane-1,2-dicarboxylic acid, the calcium salt of 3-ethylcyclohexane-1,2-dicarboxylic acid, and the lithium salt of 3-ethylcyclohexane-1,2-dicarboxylic acid. hydroxyaluminum salt, dilithium salt of 3-ethylcyclohexane-1,2-dicarboxylic acid, disodium salt of 3-n-propylcyclohexane-1,2-dicarboxylic acid, calcium salt of 3-n-propylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 3-n-propylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 3-n-propylcyclohexane-1,2-dicarboxylic acid, disodium salt of 3-isopropylcyclohexane-1,2-dicarboxylic acid, 3-isopropylcyclohexane-1,2-dicarboxylic acid calcium salt of 3-isopropylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 3-isopropylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 3-isopropylcyclohexane-1,2-dicarboxylic acid, disodium salt of 3-n-butylcyclohexane-1,2-dicarboxylic acid, calcium salt of 3-n-butylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 3-n-butylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 3-n-butylcyclohexane-1,2-dicarboxylic acid, 3-tert-butylcyclohexane-1,2- Disodium salts of dicarboxylic acids, calcium salt of 3-isobutylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 3-isobutylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 3-isobutylcyclohexane-1,2-dicarboxylic acid, disodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-methylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 4-methylcyclohexane-1,2-dicarboxylic acid, dilithium salt, disodium salt of 4-ethylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-ethylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 4-ethylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 4-ethylcyclohexane-1,2-dicarboxylic acid, disodium salt of 4-n-propylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-n-propylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 4-n-propylcyclohexane-1,2-dicarboxylic acid aluminum salt, dilithium salt of 4-n-propylcyclohexane-1,2-dicarboxylic acid, disodium salt of 4-isopropylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-isopropylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 4-isopropylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 4-isopropylcyclohexane-1,2-dicarboxylic acid, disodium salt of 4-n-butylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-n-butylcyclohexane-1,2-dicarboxylic acid salt, hydroxyaluminum salt of 4-n-butylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 4-n-butylcyclohexane-1,2-dicarboxylic acid, disodium salt of 4-tert-butylcyclohexane-1,2-dicarboxylic acid, calcium salt of 4-tert-butylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salt of 4-tert-butylcyclohexane-1,2-dicarboxylic acid, dilithium salt of 4-isobutylcyclohexane-1,2-di Examples include disodium salts of carboxylic acids, calcium salts of 4-isobutylcyclohexane-1,2-dicarboxylic acid, hydroxyaluminum salts of 4-isobutylcyclohexane-1,2-dicarboxylic acid, and dilithium salts of 4-isobutylcyclohexane-1,2-dicarboxylic acid, and among these, preferred examples include disodium salts of 3-methylcyclohexane-1,2-dicarboxylic acid, calcium salts of 4-methylcyclohexane-1,2-dicarboxylic acid, and calcium salts of 4-tert-butylcyclohexane-1,2-dicarboxylic acid.

In the metal salt of the alicyclic dicarboxylic acid, the molar ratio of cis isomers among the stereoisomers of the alkyl substituent via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt is preferably 90.0% or more, more preferably 93.0% or more, even more preferably 95.0% or more, particularly preferably 97.0% or more, and most preferably 99.0% or more, from the viewpoint of the crystallization-promoting effect when used as a crystal nucleating agent.

The following items are disclosed in this specification:

The present disclosure (1) is a method for producing a metal salt of an alicyclic dicarboxylic acid, wherein the alicyclic dicarboxylic acid is a metal salt of cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly bonded to the cyclohexane ring, the alkyl substituent being a linear or branched alkyl group having 1 to 4 carbon atoms, and the metal salt is a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt, and the method comprises the following steps (1) and (2):
Step (1): A step of obtaining an alkali metal salt or an ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent having 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent having 1 to 4 carbon atoms as a raw material. Step (2): A step of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in the step (1). The present disclosure (2) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to the present disclosure (1), in which the alkali metal salt in the step (1) is at least one selected from the group consisting of a sodium salt, a potassium salt, and a lithium salt.
The present disclosure (3) is the method for producing a metal salt of an alicyclic dicarboxylic acid according to the present disclosure (2), in which the alkali metal salt in the step (1) is a sodium salt.
The present disclosure (4) is the method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (3), wherein the catalyst for the hydrogenation reaction in the step (2) is at least one selected from the group consisting of palladium, rhodium, and ruthenium.
The present disclosure (5) is the method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (4), wherein the temperature of the hydrogenation reaction in the step (2) is 80°C or lower.
The present disclosure (6) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (5), further comprising the following step (3):
Step (3): A step of converting the hydrogenated alkali metal salt or ammonium salt obtained in the above step (2) into a calcium salt or a disodium salt. The present disclosure (7) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (6), which further comprises the following step (4) after the above step (2):
Step (4): A step of crystallizing the hydrogenated alkali metal salt or ammonium salt obtained in the step (2) The present disclosure (8) is the method for producing a metal salt of an alicyclic dicarboxylic acid according to the present disclosure (7), in which the alkali metal salt or ammonium salt crystallized in the step (4) is a monoalkali metal salt.
The present disclosure (9) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (8), wherein the alkyl substituent is at the 3- or 4-position of the cyclohexane ring.
The present disclosure (10) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (9), wherein the alkyl substituent is a methyl group.
The present disclosure (11) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (10), wherein, among stereoisomers of the alkyl substituent via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt, the molar ratio of cis isomers is 90.0% or more.
The present disclosure (12) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of the present disclosures (1) to (11), wherein the molar ratio of the cis isomer is 93.0% or more.
The present disclosure (13) is a method for producing a metal salt of an alicyclic dicarboxylic acid according to the present disclosure (7) or (8), wherein the molar ratio of the cis isomer is 95.0% or more.

The present invention will be explained in more detail below with reference to the following examples, but the present invention is not limited to these examples. The abbreviations for the compounds in the examples and the methods for measuring each property are as follows:

[Method for analyzing the obtained compound]
(1) Gas Chromatography Analysis (GC Analysis)
In each step, the molar ratio of the cis isomer among the stereoisomers of the alkyl substituents via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt was measured by GC analysis under the following conditions:
In the case of alicyclic dicarboxylic acids, the ring was closed with acetic anhydride and the measurement was performed as the acid anhydride. In the case of metal salts or ammonium salts of alicyclic dicarboxylic acids, the salts were converted back to acids with concentrated hydrochloric acid, and then the ring was closed with acetic anhydride and the measurement was performed as the acid anhydride.
<GC measurement conditions>
Model: Gas chromatograph GC-2010 (Shimadzu Corporation)
Detector: FID, 280°C
Column: DB-1701 (60 m x 0.25 mm φ x 0.25 μm)
Column temperature: 145°C
Injection temperature: 280°C
Carrier gas: helium (linear velocity: 30 cm/sec)
Injection volume: 0.1 μl (split ratio: 1/35)

After the GC analysis, the area ratio of each peak was calculated by the area percentage method, and the molar ratio of cis isomers among the stereoisomers of the alkyl substituent via the cyclohexane ring in the metal salt of an alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt was calculated by [(area ratio of cis isomer)/(area ratio of cis isomer+area ratio of trans isomer)]×100.
The fact that the molar ratio of cis-isomers in the stereoisomers does not change before and after the step of reacting the alicyclic dicarboxylic acid or its derivative [the compound obtained in steps (2) or (4)] with a metal oxide, metal hydroxide or metal chloride [the compound obtained in step (3)] was confirmed by comparing the results with those obtained by converting the obtained metal salt of the alicyclic dicarboxylic acid back into an acid anhydride and carrying out the same measurement.

In the following examples and comparative examples, the molar ratio of the cis isomer was evaluated according to the following criteria.
◎: 93% or more 〇: 90% or more but less than 93% ×: Less than 90%

Furthermore, the nuclear magnetic resonance spectroscopy analysis described below confirmed that the compounds corresponding to each retention time were alicyclic dicarboxylic acid anhydrides or their derivatives, and that their isomeric structures were cis and trans isomers of the above stereoisomers.

(2) Nuclear magnetic resonance spectroscopy (NMR analysis)
The structure of each isomer in the gas chromatography analysis was confirmed by nuclear magnetic resonance spectroscopy (NMR analysis). The conditions for NMR analysis are as follows:
NMR analyzer: trade name "DRX-500", manufactured by Bruker Solvent: deuterated dimethyl sulfoxide (DMSO-d6)
Internal standard: tetramethylsilane (TMS)
Sample tube: 5 mm
¹ H-NMR...resonance frequency: 500.1 MHz, number of accumulations: 4
¹³ C-NMR...resonance frequency: 125.8 MHz, number of accumulations: 23. The measurement sample was prepared by diluting 30 mg of the sample with 0.8 ml of solvent.
The stereostructure of the isomers was determined by measuring HMBC, HHCOYS, HMQC, and NOESY.

(3) Infrared spectroscopy (IR analysis)
FT-IR apparatus: trade name "Spectrum One", manufactured by PerkinElmer, measurement range: 650 to 4000 cm ^-1 , measurement method: ATR method, number of accumulations: 3, resolution: 4.00 cm ^-1
The measurement was performed by pressing the sample onto the cell of the device.

(4) Inductively Coupled Plasma Analysis (ICP Analysis)
ICP device: Product name "iCAP 6500Duo" manufactured by Thermo Fisher Scientific Spray chamber: Cyclone sprayer Plasma conditions: Plasma/auxiliary/carrier = 15/1.0/0.6
Plasma observation direction: axial direction three times. The measurement samples were pretreated by microwave decomposition.
Microwave device: Multiwave PRO manufactured by Anton Paar
Decomposition conditions: Approximately 0.05 g of sample and 6 mL of nitric acid (special grade) were decomposed, and then diluted with distilled water to prepare the solution.

Example 1
<Step (1)>
A 500 mL four-neck flask equipped with a stirrer and a reflux condenser was charged with 6.0 g (150 mmol) of sodium hydroxide and 125 g of ion-exchanged water, and the mixture was stirred and mixed at room temperature until the mixture was uniformly dissolved. The uniform dissolution was confirmed by visual inspection.
Subsequently, 25 g (150 mmol) of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid anhydride (also referred to as "4-MT", product name "Rikacid MT" manufactured by New Japan Chemical Co., Ltd.) was added, and the mixture was stirred and mixed while heating to dissolve uniformly, thereby obtaining a 20% by mass aqueous solution of a metal salt (sodium salt) of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid.

<Step (2)>
A 500 mL autoclave was charged with 150 g of the 20 mass % (also referred to as substrate concentration) aqueous solution of metal salt of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid obtained in the above step (1) and 0.3 g (1 mass % relative to the substrate) of a palladium/alumina-supported catalyst (also referred to as "Pd/Al ₂ O ₃ ") as a hydrogenation catalyst, and hydrogen substitution was carried out three times.
Subsequently, the reaction was carried out at 60° C. for 1 hour under a hydrogen atmosphere of 3 MPa (gauge pressure), and after the reaction was completed, the hydrogenation catalyst was removed by hot filtration.
Thereafter, water was removed by distillation using an evaporator, and the residue was dried in a vacuum at 80° C. to obtain the monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
The resulting monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid was confirmed to have a molar ratio of cis isomer of 93.5% by the above-mentioned GC analysis.

<Step (3)>
In a 500 mL four-necked flask equipped with a stirrer, a reflux condenser, and a dropping funnel, 1.92 g (48 mmol) of sodium hydroxide and 225 g of ion-exchanged water were charged and mixed with stirring at room temperature to dissolve uniformly.
After visually confirming that the solution had dissolved, 10 g (48 mmol) of the monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid obtained in the above step (2) was added, and the mixture was stirred and mixed until uniformly dissolved, thereby obtaining an aqueous solution of the disodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
The temperature of the resulting aqueous solution was raised to 80°C, and 21.2 g of a separately prepared aqueous calcium chloride solution (an aqueous solution prepared by uniformly dissolving 6.2 g (48 mmol) of calcium chloride dihydrate in 15 g of ion-exchanged water) was added dropwise over 1 hour. During the dropwise addition of the aqueous calcium chloride solution, precipitation of a white solid was observed almost simultaneously with the dropwise addition.
After the dropwise addition of the calcium chloride aqueous solution was completed, the temperature was raised to 80°C and the mixture was further heated and stirred for 1 hour and 30 minutes, after which it was filtered while hot, washed with a small amount of water, and then vacuum dried at 150°C for 10 hours, thereby obtaining 10.3 g (yield 95.7%) of the target calcium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
The structure of the obtained compound was confirmed to be the target compound by IR analysis and ICP analysis. In addition, the obtained calcium salt was back-acidified and subjected to GC analysis, which confirmed that the molar ratio of cis isomer was 93.5%.

(Examples 2 to 27)
The types and amounts of acid anhydrides, alkali metal hydroxides, and amines (also referred to as alkali metals) used in step (1) were changed as shown in the table.
In addition, the concentration of the aqueous metal salt solution of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid (also referred to as substrate concentration), the type and amount of catalyst, and reaction conditions (hydrogen pressure, reaction temperature, and reaction time) used in step (2) were changed as shown in the table.
Except for the above, the calcium salt of 4-methylcyclohexane-1,2-dicarboxylic acid was prepared in the same manner as in Example 1.

In the above examples, the catalysts used in step (2) are as follows:
<Catalyst>
Palladium/carbon-supported catalyst (also referred to as "Pd/C")
Rhodium/alumina supported catalyst (also referred to as "Rh/Al ₂ O _{3 "} )
Ruthenium/alumina supported catalyst (also referred to as "Ru/Al ₂ O ₃ ")
Trimethylamine is also expressed as "Me ₃ N," and triethylamine as "Et ₃ N."

(Examples 28 to 29)
In step (1), 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride was replaced with 4-methyl-phthalic anhydride (also referred to as "4-MePA"), and the amounts of alkali metals and the like were changed as shown in the table.
In addition, the type of catalyst used in step (2) was changed as shown in the table.
Except for the above, the calcium salt of 4-methylcyclohexane-1,2-dicarboxylic acid was prepared in the same manner as in Example 1.

(Example 30)
In step (1), 3-methyl-4-cyclohexene-1,2-dicarboxylic anhydride (also referred to as "3-MT") was used in place of 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, and the amounts of alkali metals and the like were changed as shown in the table.
In addition, the type of catalyst used in step (2) was changed as shown in the table.
Except for the above, the calcium salt of 3-methylcyclohexane-1,2-dicarboxylic acid was prepared in the same manner as in Example 1.

(Example 31)
In step (1), 4-(1-propyl)phthalic anhydride (also referred to as "4-(1-Pr)PA") was used in place of 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, and the amounts of alkali metals and the like were changed as shown in the table.
Except for the above, the calcium salt of 4-(1-propyl)cyclohexane-1,2-dicarboxylic acid was prepared in the same manner as in Example 1.

(Example 32)
In step (1), 4-t-butylphthalic anhydride (also referred to as "4-t-BuPA") was used in place of 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride, and the amounts of alkali metals and the like were changed as shown in the table.
Except for the above, the calcium salt of 4-t-butylcyclohexane-1,2-dicarboxylic acid was prepared in the same manner as in Example 1.

(Comparative Examples 1 to 3)
Step (1) was omitted, and in step (2), an aqueous solution of 4-methyl-4-cyclohexene-1,2-dicarboxylic acid (substrate concentration: 5% by mass) was used.
In step (2), the type of catalyst was changed as shown in the table.
Other than the above, the same procedure was followed as in Example 1.

(Comparative Example 4)
Step (1) was omitted, and 4-methyl-4-cyclohexene-1,2-dicarboxylic anhydride (substrate concentration 100% by mass) was used.
A 500 mL autoclave was charged with 150 g of 4-MT and 1.5 g (1% by mass relative to the substrate) of a palladium catalyst as a hydrogenation catalyst, and hydrogen substitution was carried out three times.
Subsequently, the reaction was carried out at 150° C. for 5 hours under a hydrogen atmosphere of 3 MPa (gauge pressure), and after the reaction was completed, the hydrogenation catalyst was removed by hot filtration.
In step (2), the reaction conditions (reaction temperature) were changed as shown in the table.
Other than the above, the same procedure was followed as in Example 1.

(Example 33)
Steps (1) and (2) were carried out in the same manner as in Example 1.
<Step (4)>
The monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid obtained in the above step (2) was dissolved in water heated to 60° C. to prepare an aqueous solution with a substrate concentration of 20% by mass.
The aqueous solution was then slowly cooled to 30° C. to crystallize the cis isomer of the monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
Thereafter, the mixture was filtered by suction, washed with a small amount of water to obtain a wet crystal, and then vacuum dried at 80° C. to obtain a crystal.
The filtrate obtained by suction filtration was concentrated and crystallized again in the same manner to obtain crystals.

<Step (3)>
In a 500 mL four-necked flask equipped with a stirrer, a reflux condenser, and a dropping funnel, 1.92 g (48 mmol) of sodium hydroxide and 225 g of ion-exchanged water were charged and mixed with stirring at room temperature to dissolve uniformly.
After visually confirming that the solution had dissolved, 10 g (48 mmol) of the crystals of the monosodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid obtained in the above step (4) was added, and the mixture was stirred and mixed until uniformly dissolved, thereby obtaining an aqueous solution of the disodium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
The temperature of the resulting aqueous solution was raised to 80°C, and 21.2 g of a separately prepared aqueous calcium chloride solution (an aqueous solution prepared by uniformly dissolving 6.2 g (48 mmol) of calcium chloride dihydrate in 15 g of ion-exchanged water) was added dropwise over 1 hour. During the dropwise addition of the aqueous calcium chloride solution, precipitation of a white solid was observed almost simultaneously with the dropwise addition.
After the dropwise addition of the calcium chloride aqueous solution was completed, the temperature was raised to 80°C, and the mixture was further heated and stirred for 1 hour and 30 minutes. Thereafter, the mixture was filtered while hot, washed with a small amount of water, and then vacuum dried at 150°C for 10 hours, thereby obtaining 10.3 g (yield 95.7%) of the target calcium salt of 4-methylcyclohexane-1,2-dicarboxylic acid.
The structure of the obtained compound was confirmed to be the target compound by IR analysis and ICP analysis. In addition, the obtained calcium salt was back-acidified and subjected to GC analysis, which confirmed that the molar ratio of cis isomer was 99.9% or more.

The examples confirmed that by including step (1) of obtaining an alkali metal salt or ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms as raw materials, and step (2) of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in step (1), it is possible to reduce waste and obtain a metal salt of an alicyclic dicarboxylic acid with a high molar ratio of cis isomers.

The present invention provides a method for producing a metal salt of an alicyclic dicarboxylic acid (a calcium salt, hydroxyaluminum salt, disodium salt, or dilithium salt of an alkyl-substituted 1,2-dicarboxylic acid) simply and with excellent selectivity (molar ratio of cis isomer), which can reduce waste.
Metal salts of alicyclic dicarboxylic acids (calcium salts, hydroxyaluminum salts, disodium salts, or dilithium salts of alkyl-substituted 1,2-dicarboxylic acids) have excellent properties as crystal nucleating agents for polyolefin-based resins and the like. For example, they can significantly improve the crystallization rate, i.e., the crystallization temperature, of thermoplastic resins such as polyolefin-based resins, thereby significantly shortening the molding cycle, particularly for large components, and are extremely useful for reducing costs and preventing problems during processing. Furthermore, improving the crystallinity not only improves the mechanical properties, such as rigidity, and thermal properties, such as heat resistance, of the resulting molded article, but also reduces sink marks and warpage, enabling the stable production of molded articles with complex shapes.

Claims (13)

A method for producing a metal salt of an alicyclic dicarboxylic acid, comprising the steps of:
the alicyclic dicarboxylic acid is a metal salt of cyclohexane-1,2-dicarboxylic acid having at least one alkyl substituent directly attached to the cyclohexane ring;
the alkyl substituent is a linear or branched alkyl group having 1 to 4 carbon atoms;
the metal salt is a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt;
A method for producing a metal salt of an alicyclic dicarboxylic acid, comprising the following steps (1) and (2):
Step (1): A step of obtaining an alkali metal salt or an ammonium salt using cyclohexene-1,2-dicarboxylic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms or phthalic anhydride having a linear or branched alkyl substituent with 1 to 4 carbon atoms as a raw material. Step (2): A step of performing a hydrogenation reaction using the alkali metal salt or ammonium salt obtained in step (1). The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 1, wherein the alkali metal salt in step (1) is at least one selected from the group consisting of sodium salts, potassium salts, and lithium salts. The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 2, wherein the alkali metal salt in step (1) is a sodium salt. The method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, wherein the catalyst for the hydrogenation reaction in step (2) is at least one selected from the group consisting of palladium, rhodium, and ruthenium. The method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, wherein the temperature of the hydrogenation reaction in step (2) is 80°C or lower. The method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, further comprising the following step (3):
Step (3): A step of converting the hydrogenated alkali metal salt or ammonium salt obtained in the step (2) into a calcium salt, a hydroxyaluminum salt, a disodium salt, or a dilithium salt. The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 1 or 2, further comprising the following step (4) after the step (2):
Step (4): A step of crystallizing the hydrogenated alkali metal salt or ammonium salt obtained in the step (2). The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 7, wherein the alkali metal salt or ammonium salt crystallized in step (4) is a monoalkali metal salt. The method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, wherein the alkyl substituent is at the 3rd or 4th position of the cyclohexane ring. A method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, wherein the alkyl substituent is a methyl group. The method for producing a metal salt of an alicyclic dicarboxylic acid according to any one of claims 1 to 3, wherein the molar ratio of cis isomers among stereoisomers of the alkyl substituent via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt is 90.0% or more. The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 11, wherein the molar ratio of the cis isomer is 93.0% or more. The method for producing a metal salt of an alicyclic dicarboxylic acid according to claim 7, wherein, among stereoisomers of the alkyl substituent via the cyclohexane ring of the alicyclic dicarboxylic acid and the oxycarbonyl group constituting the metal salt, the molar ratio of cis isomers is 95.0% or more.