JP2005343868A - Method for producing dieopoxidized oxalic ester compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a dieopoxidized oxalic ester compound, by which the epoxidization of an unsaturated group-containing compound can efficiently and economically be performed, and to provide a colorless and highly pure epoxy compound having a high oxirane oxygen concentration. <P>SOLUTION: This method for producing the dieopoxidized oxalic ester compound is characterized by epoxidizing a diene compound whose carbon atoms constituting the oxalic ester may have substituents (the substituents are each identically or differently a halogen atom, a 1 to 5C hydrocarbon which may contain one or more oxygen atoms or halogen atoms, or a 1 to 5C alkoxy which may have one or more substituents) with an epoxidizing agent substantially not containing water. And an epoxy compound obtained by the method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for producing a diepoxidized oxalate compound by reacting an oxalate compound with a specific organic percarboxylic acid.

Various compounds having two epoxy groups in the molecule and one or more of them having an alicyclic epoxy group are currently commercially available. For example, 3,4-epoxycyclohexylmethyl-3 ′, 4′-epoxycyclohexanecarboxylate (Celoxide 2021), 1,2,8,9-diepoxy limonene (Celoxide 3000) manufactured by Daicel Chemical Industries, ε -The caprolactone oligomer has an ester bond of 3,4-epoxycyclohexylmethanol and 3,4-epoxycyclohexanecarboxylic acid (Celoxide 2081).
These epoxy compounds react with various curing agents and curing catalysts to obtain cured products. A cured product of these epoxy compounds can have heat resistance, transparency, and good dielectric properties that are characteristic of a resin using a compound having an alicyclic skeleton. These epoxy compounds are useful as intermediates for producing coatings, adhesives, inks, sealant components, pharmaceuticals and medical supplies, and the like.

There are also a number of epoxy compounds obtained when organic peroxides such as peracetic acid are used. For example, ester compounds of 3,4-epoxycyclohexylmethyl alcohol and various (di, tri, tetra) carboxylic acids, and ester compounds of 3,4-epoxycyclohexylcarboxylic acid and various (di, tri, tetra) alcohols Is mentioned.
More specifically, 3,4-epoxycyclohexyl methanol, di (3,4-epoxycyclohexylmethyl) oxalate, di (3,4-epoxycyclohexylmethyl) malonate, di (3,4-epoxycyclohexyl) glutarate Methyl), di (3,4-epoxycyclohexylmethyl) adipate, di (3,4-epoxycyclohexylmethyl) azelate, di (3,4-epoxycyclohexylmethyl) sebacate, di (3,4-terephthalate) Epoxycyclohexylmethyl), 3,4-epoxycyclohexylcarboxylic acid, methyl 3,4-epoxycyclohexylcarboxylate, and ethyl 3,4-epoxycyclohexylcarboxylate. These epoxy compounds are selected and used according to required properties and functions.

  However, in the synthesis of alicyclic epoxy compounds that are highly reactive with acids, when organic percarboxylic acids are used, they easily react with the epoxy compounds produced by the coexisting organic acids, and the epoxy groups are opened. However, a high-purity alicyclic epoxy compound cannot be obtained. The ring opening reaction of the epoxy group by such an organic acid is promoted by the influence of water in the reaction solution.

  Even if the reaction proceeds with a high yield, it may be difficult to isolate the epoxy compound.

  For example, in U.S. Pat. No. 2,750,395, an acetone solution of peracetic acid is used as an epoxidizing agent in the synthesis of di (3,4-epoxycyclohexylmethyl) oxalate. (Cyclohexylmethyl) has a low purity of about 70% and is colored pale yellow. Distillation has been attempted for the purpose of improving the purity of di (3,4-epoxycyclohexylmethyl) oxalate obtained by synthesis. In general, oxalate esters are known to decompose at high temperatures. Distillation purification of (3,4-epoxycyclohexylmethyl) is not preferable because it involves decomposition.

  For this reason, in the synthesis of these epoxy compounds, it is effective to put an alkali salt or neutral salt in the synthesis system in advance as a means other than distillation purification for purifying peracid to high purity. It has been found that the yield of the epoxy compound is reduced by reducing the oxidation ability of the organic peracid as well as holding. Further, in Japanese Patent Application Laid-Open Nos. Sho 62-114980 and Hei 2-233688, hydrogen peroxide is used as an epoxidizing agent. A catalyst such as a metal complex is required.

  In JP-A-62-33166, hydrous hydrogen peroxide as described in West German Patent No. 2519289 is reacted in the presence of propionic acid and sulfuric acid, and subsequently produced perpropionic acid is extracted from the reaction mixture with benzene. Mentions a synthetic method using the obtained perpropionic acid reaction crude liquid as an epoxidizing agent. Since the perpropionic acid is extracted after synthesis and epoxidation is performed, the operation is long and the amount of waste is large and the operation is complicated. Furthermore, considering the extraction efficiency and cost of percarboxylic acid, the solvent becomes like benzene, which is not preferable from the viewpoint of toxicity. Moreover, the oxirane oxygen concentration of di (3,4-epoxycyclohexylmethyl) oxalate synthesized by perpropionic acid is 6.4%, which is only 62% of the theoretical value of 10.3%. It is disclosed that coloring is also observed. As described above, the conventionally known methods have problems that they cannot be produced industrially at a low cost, and a decrease in product purity and pale yellow coloring are recognized.

US Pat. No. 2,750,395 (Claims and Examples) JP-A-62-33166 (Claims, Examples)

An object of the present invention is to produce an oxalic acid ester compound having an alicyclic epoxy group in a molecule with high purity and high yield without coloring by an industrially inexpensive method.
The present inventor uses a percarboxylic acid that does not substantially contain water as an epoxidizing agent to epoxidize an oxalate ester compound having a double bond in the molecule, thereby obtaining a highly pure and colorless transparent epoxy. The present inventors have found that a compound can be produced industrially at low cost, and have reached the present invention.

That is, the first of the present invention is an oxalate-based diene which may have a substituent on each constituting carbon atom (the substituent is a halogen atom or an oxygen atom or a halogen atom containing 1 halogen atom) By an epoxidizing agent substantially free of moisture), which may be a hydrocarbon group having ˜5 or an alkoxy group having 1 to 5 carbon atoms which may have a substituent, and may be the same or different. Provided is a process for producing a diepoxidized oxalate compound characterized by epoxidation. The second of the present invention is
Oxalic acid ester-based dienes represented by the above general formula (II) are oxalic acid ester compounds (X ¹ and X ² are optionally substituted C ₁ to C ₅ alkylene groups, substituent R ^1. to R ¹⁸ is a halogen atom or an oxygen atom or a hydrocarbon group having 1 to 5 carbon atoms which may contain a halogen atom or an optionally substituted alkoxy group having 1 to 5 carbon atoms,, A method for producing a diepoxidized oxalate compound according to the above invention 1 is provided, which may be the same or different.
A third aspect of the present invention is the production of the diepoxidized oxalate compound according to the above-mentioned invention 2, wherein X ¹ and X ² in the general formula (II) are both CH ₂ and R ^{1 to} R ¹⁸ are all hydrogen atoms. Provide a method. 4th of this invention provides the manufacturing method of the diepoxidized oxalate compound in any one of the said invention 1-3 whose epoxidizing agent is the organic percarboxylic acid obtained by oxidation of the corresponding aldehyde. .
5th of this invention provides the manufacturing method of the diepoxidation oxalate compound in any one of the said invention 1-4 whose water | moisture content in an epoxidizing agent is 0.8 weight% or less. 6th of this invention provides the manufacturing method of the diepoxidized oxalate ester compound in any one of the said invention 1-5 whose epoxidizing agent is peracetic acid.
A seventh aspect of the present invention is the method for producing a diepoxidized oxalate compound according to the sixth aspect, wherein the peracetic acid is an ethyl acetate solution. 8th of this invention provides the manufacturing method of the diepoxidized oxalate compound in any one of the said invention 1-7 by which epoxidation is performed at less than 70 degreeC.
9th of this invention neutralizes the acidic component after completion | finish of reaction with the weak alkaline aqueous solution of pH7-11, and the manufacturing method of the diepoxidized oxalate ester compound in any one of the said invention 1-8 which removes by water washing. provide. 10th of this invention provides the manufacturing method of the diepoxidized oxalate compound of the said invention 9 whose weak alkali aqueous solution is sodium hydrogencarbonate aqueous solution. The eleventh aspect of the present invention provides a diepoxidized oxalate compound having an oxirane oxygen concentration of 90 to 100% of the theoretical value.

  According to the production method of the present invention, an oxalate ester compound having an oxirane oxygen concentration and an uncolored epoxy group can be produced with high purity and high yield.

The present invention will be described in detail below.
The diepoxylated oxalate compound of the present invention can be produced, for example, by reacting a diene having an alicyclic skeleton with an epoxidizing agent such as peracetic acid.
As the oxalate-based dienes, the following general formula (II),
The diene compound represented by these is preferably used. In the above formula (II), X ¹ and X ² are an optionally substituted C ₁ to C ₅ alkylene group, and the substituents R ^{1 to} R ¹⁸ include a halogen atom, an oxygen atom or a halogen atom. A hydrocarbon group having 1 to 5 carbon atoms which may be present, or an alkoxy group having 1 to 5 carbon atoms which may have a substituent, which may be the same or different. Among them, it is preferable to use di (3,4-cyclohexenylmethyl) oxalate in which X ¹ and X ² are both CH ₂ and R ^{1 to} R ¹⁸ are all hydrogen atoms because of easy availability.
When the oxalate diene compound represented by the above formula (II) is epoxidized, it becomes an epoxy compound represented by the following formula (I).
In the above formula (I), X ¹ and X ² and substituents R ^{1 to} R ¹⁸ are the same as in the case of the oxalate-based diene compound represented by the above formula (II).

As an epoxidizing agent that can be used, a percarboxylic acid that is substantially free of moisture is used as an epoxidizing agent that is substantially free of moisture. The epoxidation reaction in the presence of water is because the ring-opening reaction of the epoxy group proceeds and the yield of the diepoxidized oxalate compound decreases.
The percarboxylic acid substantially free of moisture referred to in the present invention is, for example, peracetic acid produced by air oxidation of acetaldehyde. Examples of the method for producing such a percarboxylic acid include the methods described in German Published Patent No. 1418465 and Japanese Patent Laid-Open No. 54-30006. The water content of the percarboxylic acid used in the present invention is 0.8 to 0.1%, preferably 0.6 to 0.3%.
Compared with the case where percarboxylic acid is synthesized from hydrogen peroxide and extracted into a solvent as disclosed in JP-A-62-33166, the water content is continuously low. Since percarboxylic acids can be synthesized in large quantities at high concentrations, a substantially inexpensive process can be made.

As the peracids, formic acid, peracetic acid, perbenzoic acid, trifluoroperacetic acid and the like can be used. Of these, peracetic acid is a preferred epoxidizing agent that can be produced industrially at low cost and has high stability.
There is no strict restriction on the amount of epoxidizing agent, and the optimum amount in each case is the type of epoxidizing agent, the desired degree of epoxidation (oxirane oxygen concentration), the individual oxalate-based dienes used, etc. It depends on variable factors such as The epoxidation reaction is carried out by adjusting the presence or absence of an inert solvent and the reaction temperature in accordance with the equipment and physical properties of the raw materials. As the inert solvent, it can be used for the purpose of reducing the viscosity of the raw material, stabilizing by diluting the epoxidizing agent, and in the case of peracetic acid, aromatic compounds, ethers, esters, etc. can be used. it can.
Particularly preferred solvents are hexane, cyclohexane, toluene, benzene and ethyl acetate, with ethyl acetate being particularly preferred.

The reaction temperature range that can be used is determined by the reactivity of the epoxidizing agent used. Speaking of peracetic acid which is a preferred epoxidizing agent, 20 to 70 ° C. is preferable. The reaction is slow at 20 ° C. or lower, and peracetic acid is decomposed at 70 ° C. or higher.
The molar ratio of the epoxidizing agent to the unsaturated bond can be changed according to the purpose such as how much unsaturated bond is desired to remain.
In the present invention where a compound having a large number of epoxy groups is intended, the epoxidizing agent is preferably added in an equimolar amount or more with respect to the unsaturated groups. However, it is usually disadvantageous to exceed 2 times mol due to economical problems and side reactions described below. In the case of peracetic acid, 1 to 1.5 times mol is preferable.
The epoxidation reaction is desirably carried out by sequentially adding an organic percarboxylic acid dropwise or the like in the presence of an oxalate-based diene compound (dienes).

In the present invention, no special operation is required for the epoxidation reaction. For example, after the completion of dropwise addition of the organic percarboxylic acid, the reaction crude liquid may be aged by stirring for 1 to 5 hours.
Isolation of oxalic acid esters from the resulting reaction crude liquid can be performed by an appropriate method, for example, a method of precipitation with a poor solvent or the like, a direct desolvation method, or the like.
For oxalic acid di (3,4-epoxycyclohexylmethyl), the epoxy ring is easy to open with an organic acid and the oxalic acid ester group is easily decomposed by heat. High-purity diepoxy is associated with epoxy ring-opening or decomposition of oxalate groups when solvent removal is performed or when the solvent is distilled off under stirring in hot water. The compound cannot be obtained.

After completion of the reaction, the washing is preferably neutralized at a low temperature. The neutralizer is preferably a weak basic salt. For example, sodium hydrogen carbonate, lithium hydrogen carbonate, potassium hydrogen carbonate and the like can be mentioned. It is also desirable to perform neutralization washing with a low-concentration caustic soda aqueous solution adjusted to pH 7-11. When neutralized with an alkali exceeding pH 11, decomposition of the oxalate ester may occur, which causes a decrease in yield.
For example, when sodium hydrogen carbonate is used, it causes a neutralization reaction with an organic acid, soda acetate is generated, and soda acetate acts as a buffer material, and the specific gravity difference increases by increasing the specific gravity on the inorganic layer side. Liquidity is improved. Neutralization is also effective for suppressing coloration of the epoxy compound. After performing this neutralization washing, it is desirable to wash out the produced neutralized salt with water and distill off the solvent. If the neutralization treatment is not performed, a large amount of water is consumed, which is undesirable from the viewpoint of cost and environmental load.
In the production method of the present invention, it is not necessary to use various metal catalysts in combination as in the case of using hydrogen peroxide as an epoxidizing agent.

The neutralizing agent is preferably a weak basic salt. For example, sodium hydrogen carbonate, potassium hydrogen carbonate, lithium hydrogen carbonate and the like. Neutralization with a strongly basic salt such as sodium hydroxide is undesirable because it causes hydrolysis of the oxalate group and causes an extreme yield reduction.
What is necessary is just to remove a low boiling-point compound from the organic layer after neutralization by distillation operation.

The oxirane oxygen concentration in the diepoxy compound obtained by the production method of the present invention as described above is usually about 90 to 100% of the theoretical value. Further, depending on the application, there is no problem even if a monoepoxy compound in which one unsaturated bond is not epoxidized is mixed.
The epoxy compound produced by the production method of the present invention can be used for various coatings, inks, adhesives, sealants, moldings or other applications using these by homopolymerization, copolymerization or further reaction with other compounds. Intermediates can be produced.

  Examples of end uses in which the epoxy compound produced by the production method of the present invention can be used include acid removers, furniture coatings, decorative coatings, automotive undercoats, sealers, finish coats, beverage cans and other can coatings, letters Ink for information or image information, sealant for electronic components, photoresist suitable for developing printing plate or printed circuit board, cast printing roll, unsaturated polyester and styrene mainly glass, carbon, graphite or others There are moldings, solvents, flame retardants and the like made with molding compounds or sheet-forming formulations reinforced with fibers.

(Example)
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto.

Dienes were synthesized as follows.
(Synthesis Example 1) <Synthesis of di (3,4-cyclohexenylmethyl) oxalate>
709 g (6 mol) of dimethyl oxalate, 2020 g (18 mol) of 3,4-cyclohexenylmethanol and 15 g (0.06 mol) of lithium hydroxide in a 3 liter flask equipped with an Oldershaw distillation column (φ50, 10 stages) at the top The temperature in the reaction system was set to 170 ° C. while charging and blowing nitrogen into the gas phase. Shortly after that, the distillation of methanol started, and 350 g was distilled by 18 hours, and the distillation of methanol stopped.
The reaction solution was cooled to room temperature and dissolved in 2000 g of ethyl acetate, and then 700 g of water was added and washed with water. Washing with water was performed twice. This operation removed the catalyst.
A solution of crude di (3,4-cyclohexenylmethyl) oxalate in ethyl acetate was added to a 3 liter flask equipped with an Oldershaw type distillation column (φ50, 10 stages) at the top, and the low-boiling compounds were distilled off. Di (3,4-cyclohexenylmethyl) oxalate was purified by distillation under reduced pressure at 170 ° C. and 1.2 Torr. The yield was 1 kg, the yield was 65%, and the purity (gas chromatography) was 99.2%.

(Example 1)
<Synthesis 1 of Epoxidized Dioxalate (3,4-Cyclohexenylmethyl)>
A 2 liter flask was charged with 400 g of di (3,4-cyclohexenylmethyl) oxalate and 1200 g of ethyl acetate, and nitrogen was blown into the gas phase, and the temperature in the reaction system was adjusted to 40 ° C. for about 2 hours. 913 g of a substantially anhydrous ethyl acetate solution of peracetic acid (peracetic acid concentration; 28.7%, water content 0.38%) was added dropwise. After the peracetic acid solution was dropped, the reaction was terminated by aging at 30 ° C. for 3 hours.
Next, 2000 g of a saturated aqueous sodium hydrogen carbonate solution having a pH of 9 was added to the reaction solution, and a liquid separation operation was performed. After performing the same liquid separation operation again, 1000 g of water was added to perform the liquid separation operation. The low boiling point compound was removed at 70 ° C./20 mmHg to obtain 420 g of a colorless and transparent epoxy compound. The yield was 94%, the purity (gas chromatography) was 98.3%, and the properties of the obtained product were an oxirane oxygen concentration of 10.1% by weight, a viscosity of 800 mPa · s / 25 ° C., and a Hazen color number of 10 or less. ^{From 1} HNMR, a peak derived from an internal double bond in the vicinity of δ4.5 to 5 ppm disappeared, and a proton peak derived from an epoxy group was confirmed in the vicinity of δ2.9 to 3.1 ppm.

(Comparative Example 1-Comparison regarding neutralization after epoxidation)
<Synthesis 2 of Epoxidized Di (3,4-cyclohexenylmethyl) oxalate>
A 2 L flask was charged with 400 g of di (3,4-cyclohexenylmethyl) oxalate and 1200 g of ethyl acetate, and while the nitrogen gas was blown into the gas phase part, the temperature in the reaction system was adjusted to 40 ° C. over about 2 hours. 913 g of substantially anhydrous peracetic acid in ethyl acetate (peracetic acid concentration: 28.7%, water content 0.38%) was added dropwise. After the peracetic acid solution was dropped, the reaction was terminated by aging at 30 ° C. for 3 hours.
Next, 2000 g of a 10% aqueous sodium hydroxide solution having a pH of 13 was added to the reaction solution, and the acidic component was washed away with water to carry out a liquid separation operation. After performing the same liquid separation operation again, 1000 g of water was added to perform the liquid separation operation. The low boiling point compound was removed at 70 ° C./20 mmHg to obtain 137 g of a light yellow epoxy compound. Yield 31%, purity 78%. The properties of the obtained product were an oxirane oxygen concentration of 7.9% by weight, a viscosity of 640 mPa · s / 25 ° C., and a Hazen color number of 50.

Claims (11)

  Oxalate-based dienes that may have a substituent on each carbon atom (the substituent is a halogen atom, an oxygen atom or a hydrocarbon group having 1 to 5 carbon atoms that may contain a halogen atom, or substitution) A diepoxy characterized by epoxidizing an alkoxy group having 1 to 5 carbon atoms which may have a group, which may be the same or different, with an epoxidizing agent substantially free of moisture A method for producing an oxalate compound. Oxalic acid ester-based dienes represented by the above general formula (II) are oxalic acid ester compounds (X ¹ and X ² are optionally substituted C ₁ to C ₅ alkylene groups, substituent R ^1. to R ¹⁸ is a halogen atom or an oxygen atom or a hydrocarbon group having 1 to 5 carbon atoms which may contain a halogen atom or an optionally substituted alkoxy group having 1 to 5 carbon atoms,, 2. The method for producing a diepoxylated oxalate compound according to claim 1, wherein each may be the same or different. The method for producing a diepoxylated oxalate compound according to claim 2, wherein X ¹ and X ² in the general formula (II) are both CH ₂ , and R ^{1 to} R ¹⁸ are all hydrogen atoms.   The method for producing a diepoxidized oxalate compound according to any one of claims 1 to 3, wherein the epoxidizing agent is an organic percarboxylic acid obtained by oxidation of a corresponding aldehyde.   The method for producing a diepoxidized oxalate compound according to any one of claims 1 to 4, wherein water in the epoxidizing agent is 0.8% by weight or less.   The method for producing a diepoxidized oxalate compound according to any one of claims 1 to 5, wherein the epoxidizing agent is peracetic acid.   The method for producing a diepoxidized oxalate compound according to claim 6, wherein the peracetic acid is an ethyl acetate solution.   The method for producing a diepoxidized oxalate compound according to any one of claims 1 to 7, wherein the epoxidation is performed at less than 70 ° C.   The method for producing a diepoxidized oxalate compound according to any one of claims 1 to 8, wherein the acidic component after completion of the reaction is neutralized with a weak alkaline aqueous solution having a pH of 7 to 11, and washed and removed with water.   The method for producing a diepoxidized oxalate compound according to claim 9, wherein the weak alkaline aqueous solution is an aqueous sodium hydrogen carbonate solution.   A diepoxidized oxalate compound having an oxirane oxygen concentration of 90 to 100% of the theoretical value.