JP5311390B2 - Method for producing onium tetrakis acyloxyborate - Google Patents

Description

  The present invention relates to a method for producing onium tetrakis acyloxyborate useful as a curing catalyst for epoxy resin of electric / electronic materials.

  It is known that onium tetrakis acyloxy borate compounds such as tetra-substituted phosphonium tetrakis acyloxy borate serve as curing catalysts such as epoxy resins (Patent Documents 1 and 2), and their production methods have also been proposed. However, since the compound has problems in handling and the like, it has been difficult to produce industrially.

  Under such circumstances, as a method capable of industrial production, a production method using tetrakis acyloxyborate alkali metal and onium salt has been proposed (Patent Document 3). However, although a certain yield can be obtained by the method described in Patent Document 3, further improvement is necessary because a satisfactory yield cannot be obtained.

JP-A-8-196911 JP 2001-261684 A JP-A-2005-220038

  The present invention provides a method for producing onium tetrakis acyloxyborate stably and with high yield.

  The present invention provides a method for producing onium tetrakisacyloxyborate in which a tetrakisacyloxyborate alkali metal salt is reacted with an onium salt in the presence of an alkali hydroxide.

  The production method of onium tetrakisacyloxyborate in which the aprotic polar solvent solution of the tetrakisacyloxyborate alkali metal salt and the alkali hydroxide is reacted with the alcohol solution of the onium salt is a preferred embodiment of the present invention.

  The method for producing onium tetrakisacyloxyborate described above, in which the onium tetrakisacyloxyborate is tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate is a preferred embodiment of the present invention.

The present invention provides a production method capable of producing onium tetrakis acyloxyborate in high yield.
By this invention, the manufacturing method which can manufacture onium tetrakis acyloxy borate industrially is provided.
According to the present invention, tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate can be produced industrially in high yield.

  The present invention provides a method for producing onium tetrakisacyloxyborate in which a tetrakisacyloxyborate alkali metal salt is reacted with an onium salt in the presence of an alkali hydroxide.

  As the tetrakis acyloxyborate alkali metal salt used in the present invention, the acyloxy group is an aliphatic acyloxy group such as an acetoxy group or propionyloxy group, an alicyclic acyloxy group such as a cyclohexanecarboxy group, a benzoyloxy group, 1 -What is monocyclic aromatic and polycyclic aromatic acyloxy groups, such as a naphthoyloxy group and 2-naphthoyloxy group, can be illustrated.

  Moreover, as said alkali metal salt, salts, such as lithium, sodium, potassium, can be used. Among these, considering availability, it is most preferable to use a sodium salt that can be synthesized by a simple method using sodium borohydride and an organic carboxylic acid as raw materials. As a method for producing a sodium salt by this method, the method described in Patent Document 3 can be employed.

  Preferable specific examples of the tetrakis acyloxyborate alkali metal salt of the present invention include sodium tetrakis (1-naphthoyloxy) borate, sodium tetrakis (2-naphthoyloxy) borate, potassium tetrakis (1-naphthoyloxy) borate, potassium tetrakis (2-naphthoyloxy) Examples thereof include, but are not limited to, borate, lithium tetrakis (1-naphthoyloxy) borate, and lithium tetrakis (2-naphthoyloxy) borate.

In the present invention, as a method of reacting tetrakisacyloxyborate alkali metal salt and onium salt in the presence of an alkali hydroxide, an aprotic polar solvent solution of tetrakisacyloxyborate alkali metal salt and alkali hydroxide is used. The method of making it react with the alcohol solution of the said onium salt can be mentioned as a preferable aspect.
The aprotic polar solvent solution of tetrakisacyloxyborate alkali metal salt and alkali hydroxide should be a solution obtained by adding an aprotic polar solvent and alkali hydroxide to tetrakisacyloxyborate alkali metal salt. Can do.

  When a protic solvent such as alcohol is used as a solvent for dissolving the tetrakis acyloxyborate alkali metal salt, the tetrakis acyloxyborate alkali metal salt is easily decomposed. An aprotic polar solvent is a preferred solvent because it is relatively stable. Examples of aprotic polar solvents include ketone solvents such as acetone, methyl ethyl ketone, 2-pentanone, 3-pentanone, 2-hexanone, methyl isobutyl ketone, acetophenone, acetonitrile, nitrobenzene, N, N-dimethylformamide, pyridine and the like. Examples include nitrogen solvents, ether solvents such as tetrahydrofuran and dioxane, and acetone is more preferable.

  The amount of acetone used as the solvent is 2 to 20 times by weight, more preferably 3 to 10 times by weight, relative to the tetrakisacyloxyborate alkali metal salt.

  Examples of the alkali hydroxide added to the tetrakisacyloxyborate alkali metal salt solution include sodium hydroxide, potassium hydroxide, lithium hydroxide and the like, and sodium hydroxide is preferred. The alkali hydroxide can be used as a solid or a solution, but is preferably used as an aqueous solution.

  In order to obtain onium tetrakisacyloxyborate in good yield, the pH of the aprotic polar solvent solution of tetrakisacyloxyborate alkali metal salt is preferably 7 to 16, more preferably pH 9 to 15, and still more preferably pH 12 to 15.

  Examples of the onium salt to be reacted with the tetrakis acyloxyborate alkali metal salt include a tetra-substituted phosphonium salt, a tetra-substituted ammonium salt, and a tri-substituted sulfonium salt. In these onium salts, the substituent is a hydrocarbon group such as an alkyl group, a cycloalkyl group or an aryl group, and the salt is preferably a halide such as chloride, bromide or iodide. Considering the function of the epoxy resin as a curing catalyst, it is preferable to use a tetraarylphosphonium salt having an aryl group such as a phenyl group or a tolyl group, and considering the cost, tetraphenylphosphonium bromide is a preferable example. However, the present invention is not limited to this.

Alcohols used for the preparation of onium salt alcohol solutions include monohydric alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, tert-butanol, ethylene glycol, diethylene glycol, and glycerin. Examples thereof include monohydric alcohols. Alcohol is a good solvent for the onium salt and a poor solvent for the product onium tetrakisacyloxyborate, and because the by-product alkali metal salt has high solubility, the alkali metal salt of the onium tetrakisacyloxyborate crystals Mixing can be reduced. Among these alcohols, monohydric alcohols are preferably used, and methanol is more preferable.
The amount of alcohol used as the solvent is preferably 10 times or more by weight of the onium salt, more preferably 20 to 100 times by weight.

  In the present invention, the conditions for reacting the tetrakis acyloxyborate alkali metal salt with the onium salt in the presence of an alkali hydroxide are not particularly limited, and can be appropriately selected from conventionally known reaction conditions. A preferred embodiment of the reaction of the present invention is a method in which a solution of tetrakisacyloxyborate alkali metal salt is suitably applied to a solution of onium salt over a period of about 2 to 8 hours at a temperature of room temperature to about 60 ° C. be able to.

  The method for recovering the onium tetrakis acyloxyborate produced by the reaction is not particularly limited and can be appropriately selected from conventionally known reaction conditions.

  As the onium tetrakisacyloxyborate obtained in the present invention, tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate is preferable in that a raw material can be industrially obtained.

The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to these examples.
The measuring method used in the present invention is as follows.

[Analysis method]
High performance liquid chromatography (HPLC)
(HPLC measurement conditions)
Column: Chemical Inspection Association L column ODS 4.6 x 250 mm
Column temperature: 40 ° C
Flow rate: 1 mL / min
Mobile phase: (A) Methanol (B) 0.1% aqueous phosphoric acid Mobile phase program gradient

Sample preparation: Solvent DMF (20 ml) is added to sample (50 mg) and dissolved to prepare an injection sample Injection volume: 5 μL
Detector: UV = 288 nm
Sodium ion concentration: Hot water extraction method (analyzed with an atomic absorption photometer)

[Example 1]
A reaction kettle was charged with 3375 parts by weight of methanol and 167 parts by weight of tetraphenylphosphonium bromide, dissolved under stirring, and kept at 55 ° C. In another reaction kettle, 280 parts by weight of sodium tetrakis (1-naphthoyloxy) borate and 941 parts by weight of acetone were charged and dissolved at 20 ° C., until the pH of the acetone solution of sodium tetrakis (1-naphthoyloxy) borate reached 15. 10% NaOH aqueous solution was added. The acetone solution of sodium tetrakis (1-naphthoyloxy) borate thus prepared was added dropwise over 4 hours to a methanol solution of tetraphenylphosphonium bromide. It was confirmed that a crystal of the reaction product was deposited along with the dropwise addition.

After completion of dropping, the mixture was cooled to 30 ° C., and the precipitated crystals were separated by filtration, washed with 3600 parts by weight of methanol, and further dried by heating under vacuum to obtain 363 parts by weight of tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate. Got. The reaction of this example is represented by the following formula, and the product tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate is a compound represented by the formula (1).
The purity of the product was measured by HPLC. As a result, the surface concentration was 100%.
The sodium ion concentration was 40 ppm. Table 2 summarizes the results.

[Example 2]
The reaction was performed in the same manner as in Example 1 except that the pH of the acetone solution of sodium tetrakis (1-naphthoyloxy) borate was adjusted to 11. 335 parts by weight of tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate represented by the formula (1) was obtained.
The purity of the product was measured by HPLC. As a result, the surface concentration was 100%.
The sodium ion concentration was 50 ppm. Table 2 summarizes the results.

[Example 3]
The reaction was conducted in the same manner as in Example 1 except that the pH of the acetone solution of sodium tetrakis (1-naphthoyloxy) borate was adjusted to 9. 319 parts by weight of tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate represented by the above formula (1) was obtained. The purity of the product was measured by HPLC. As a result, the surface concentration was 100%. The sodium ion concentration was 60 ppm. Table 2 summarizes the results.

[Comparative Example 1]
A reaction kettle was charged with 3375 parts by weight of methanol and 167 parts by weight of tetraphenylphosphonium bromide, dissolved under stirring, and kept at 55 ° C. In another reaction kettle, 280 parts by weight of sodium tetrakis (1-naphthoyloxy) borate and 941 parts by weight of acetone were charged. For 4 hours. It was confirmed that a crystal of the reaction product was deposited along with the dropwise addition.

After completion of the dropwise addition, the mixture was cooled to 30 ° C., and the precipitated crystals were separated by filtration, washed with 3600 parts by weight of methanol, and further dried by heating under vacuum, whereby the tetraphenylphosphonium tetrakis represented by the above formula (1) ( 303 parts by weight of 1-naphthoyloxy) borate was obtained. When the purity of the above product was measured by HPLC, the area percentage was 100%.
The sodium ion concentration was 70 ppm. Table 2 summarizes the results.

[Comparative Example 2]
The reaction was conducted in the same manner as in Comparative Example 1 except that sodium tetrakis (1-naphthoyloxy) borate was dissolved in methanol. After completion of the reaction, crystals were not precipitated even when cooled, and a large amount of 1-naphthoic acid was detected in the reaction solution. Table 2 shows the results.

  In Examples 1-3, it turned out that onium tetrakis acyloxyborate is obtained with a high yield. This is considered to be a result of inhibiting the decomposition of the tetrakis acyloxyborate alkali metal during the reaction.

According to the present invention, onium tetrakis acyloxyborate can be obtained in high yield with good workability by industrial production.
By the production method provided by the present invention, tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate can be produced industrially in high yield.

Claims (8)

A method for producing onium tetrakisacyloxyborate, comprising reacting an alkali metal tetrakisacyloxyborate with an onium salt in the presence of an alkali hydroxide. The method for producing onium tetrakisacyloxyborate according to claim 1, wherein an aprotic polar solvent solution of tetrakisacyloxyborate alkali metal salt and alkali hydroxide is reacted with an alcohol solution of onium salt. The method for producing onium tetrakis acyloxyborate according to claim 2, wherein the aprotic polar solvent is acetone. The method for producing onium tetrakis acyloxyborate according to any one of claims 1 to 3, wherein the alkali hydroxide is sodium hydroxide. The method for producing onium tetrakisacyloxyborate according to claim 2 or 3, wherein the alcohol in the alcohol solution of the onium salt is methanol. The method for producing onium tetrakisacyloxyborate according to any one of claims 1 to 5, wherein the tetrakisacyloxyborate alkali metal salt is sodium tetrakis (1-naphthoyloxy) borate. The method for producing onium tetrakisacyloxyborate according to any one of claims 1 to 6, wherein the onium salt is tetraphenylphosphonium bromide. The method for producing onium tetrakisacyloxyborate according to any one of claims 1 to 7, wherein the onium tetrakisacyloxyborate is tetraphenylphosphonium tetrakis (1-naphthoyloxy) borate.