JPH05247016A - Production of epoxidized glycidyl esters - Google Patents

Abstract

PURPOSE:To suppress the loss of glycidyl esters by hydrolysis or polymerization and advantageously obtain the subject compounds by applying a specific catalyst system in epoxidizing the glycidyl esters having cyclohexene rings with hydrogen peroxide. CONSTITUTION:Glycidyl esters of formula I [R<1> and R<2> are H or methyl; A is alkylene; (n) is 0-5] having cyclohexene rings are epoxidized with hydrogen peroxide by using a system composed of one or more oxidation catalysts selected from tungstic acids and molybdenic acids, long-chain alkyl group- containing quaternary ammonium salts or long-chain alkyl group-containing phosphonium salts and phosphate anions as a catalyst to afford the objective glycidyl esters of formula II having epoxycyclohexene rings. The loss of the glycidyl esters by hydrolysis or polymerizing reaction is suppressed as much as possible by using this catalyst system and the objective compounds of formula II are industrially and advantageously obtained.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing glycidyl esters having an epoxycyclohexane ring.

[0002]

2. Description of the Related Art In recent years, there has been an increasing demand for highly heat-resistant encapsulants for electronic parts and coating films having a high cross-link density, and along with this, various forms of polyfunctional epoxy compounds are required.

In compounds having both a glycidyl group and an alicyclic epoxy group in the molecule, these two types of epoxy groups have unique curing characteristics, and a structure having a cyclohexane ring has weather resistance and heat resistance. From the viewpoint of excellent properties, it is considered to be an epoxy compound that can meet diversifying needs.

The above-mentioned epoxy compound is a compound prepared by epoxidizing glycidyl esters having a cyclohexene ring.

Hydrogen peroxide, which is already known as an epoxidizing agent, is an inexpensive and relatively safe compound, and an advantageous oxidizing agent as compared with expensive and difficult-to-operate organic peracids. However, in general, a glycidyl ester group is a functional group having strong hydrolyzability, and particularly under acidic conditions, the tendency is strong, and it is transformed into an ether group or a hydroxyl group. The technology of epoxidizing by epoxidation has not been known so far.

[0006]

DISCLOSURE OF THE INVENTION The present inventors have made earnest studies on the epoxidation of glycidyl esters having a cyclohexene ring with hydrogen peroxide, and as a result, by applying a specific catalyst system, glycidyl esters have been applied. It was found that glycidyl esters having an epoxycyclohexane ring as a basic skeleton can be produced under industrially advantageous conditions by suppressing the loss due to hydrolysis or polymerization reaction of as much as possible, and the present invention was completed based on such findings. Came to do.

That is, an object of the present invention is to provide a process for producing glycidyl esters having a novel and useful epoxy cyclohexane ring obtained by epoxidizing with hydrogen peroxide.

[0008]

A method for producing a glycidyl ester having an epoxycyclohexane ring represented by the general formula (II) according to the present invention is a glycidyl ester having a cyclohexene ring represented by the general formula (I). (2) a long-chain alkyl group-containing quaternary compound (1) one or more oxidation catalysts selected from tungstic acids and molybdic acids in a water-organic solvent two-phase system. In the presence of an ammonium salt or a phosphonium salt containing a long-chain alkyl group and (3) a phosphate anion,
It is characterized in that it is epoxidized with hydrogen peroxide.

[In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group, and A represents an alkylene group. n represents 0-5. ]

[In the formula, R ¹ , R ² , A and n are the same as those in the general formula I.] ]

Examples of the glycidyl ester having a cyclohexene ring in the present invention include glycidyl ester derivatives of tetrahydrophthalic acid and methyltetrahydrophthalic acid, and specifically, diglycidyl tetrahydrophthalate, diglycidyl methyltetrahydrophthalate and alkylene. Bis (2-glycidyloxycarbonyl-4-cyclohexenylcarbonyloxy), alkylenebis (2-glycidyloxycarbonyl-3-methyl-4-cyclohexenylcarbonyloxy), alkylenebis (2-glycidyloxycarbonyl-4-)
Examples include methyl-4-cyclohexenylcarbonyloxy) and oligomers that are by-produced when preparing these epoxidation raw materials.

As the alkylene in the above compound,
A linear, branched or alicyclic divalent group having 2 to 15 carbon atoms is mentioned, and examples of the divalent alcohol applied for introducing such a group include ethylene glycol, propylene glycol and butanediol. , Pentanediol, hexanediol, heptanediol, octanediol, nonanediol, decanediol, dodecanediol and their branched alcohols, cyclohexanediol, cyclohexanedimethanol, 3,8-dihydroxytricyclo [5,2,1,0 ^{2 , 5} ] decane, 4,
9-dihydroxytricyclo [5,2,1,0 ^2,5 ] decane, 3,8-bis (hydroxymethyl) tricyclo [5,2,1,0 ^2,5 ] decane, 4,9-bis (hydroxy) Methyl) tricyclo [5,2,1,0 ^2,5 ] decane, 2,2-bis (4-hydroxycyclohexyl) propane [hydrogenated bisphenol A], 2,2-bis (4-
(Hydroxycyclohexyl) methane, bicyclohexanol, etc. may be mentioned.

The tungstic acid, which is one of the oxidation catalysts in the present invention, is generally a compound capable of forming a tungstate anion in water, and includes, for example, tungstic acid, alkali tungstate, ammonium tungstate, tungsten trioxide and tritungstic acid. Mention may be made of tungsten sulphide, tungsten hexachloride, phosphotungstic acid, silicotungstic acid, borotungstic acid and the like.

The molybdic acid, which is also one kind of oxidation catalyst, is a compound that can generally generate a molybdate anion in water, and includes, for example, molybdic acid, alkali molybdate, ammonium molybdate, molybdenum trioxide, and trioxide. Mention may be made of molybdenum sulfide, molybdenum hexachloride, phosphomolybdic acid, silicomolybdic acid, boromolybdic acid and the like.

The amount of these oxidation catalysts used is about 0.1-10% by weight, preferably 0.5-5, relative to the reaction substrate.
It is about% by weight. If it is less than this, the reaction is remarkably slow, so hydrolysis of the glycidyl group is relatively likely to occur,
Many more catalysts are economically disadvantageous.

The long-chain alkyl-containing quaternary ammonium salt or the long-chain alkyl-containing phosphonium salt according to the present invention is
In the reaction, it functions as a phase transfer catalyst. As such a compound, specifically, a quaternary ammonium or phosphonium chloride or bromide whose alkyl group has a total carbon number of 20 or more is effective.
When the number of carbon atoms is smaller than this, it is not preferable because the salt with the oxidation catalyst tends to be unable to effectively perform phase transfer between the organic phase and the aqueous phase.

The required amount of the above-mentioned phase transfer catalyst depends on the nature of the alkyl group, but is 0.
It is about 01 to 5% by weight, preferably about 0.1 to 3% by weight. If it is less than this, the ability as a phase transfer catalyst cannot be achieved, and even if more catalyst is added, the ability of the oxidation catalyst cannot be enhanced.

The phosphoric acid anion is added as phosphoric acid or a phosphoric acid salt, and the addition amount thereof is about 0.05 to 5 times mol, preferably 0.5 to 5 times, with respect to the oxidation catalyst to be applied.
It is about 3 times the molar amount. If it is less than this range, the activity of the oxidation catalyst is lowered, which is not preferable, and conversely, even if it is increased, no superiority is recognized.

The aqueous phase containing the phosphate anion and the oxidation catalyst is
P with mineral acid or alkali hydroxide or alkali carbonate
It is desirable that the pH is adjusted to H2-5, preferably pH3-4. The lower the pH, the higher the reaction rate, but conversely the selectivity decreases. On the other hand, if the pH is too high, the reaction rate becomes slow, the hydrolysis reaction of the glycidyl group proceeds within the reaction time, and as a result, the reaction selectivity decreases.

The amount of hydrogen peroxide used is appropriately about 1 to 2 times the molar amount of the reaction substrate, and more preferably about 1.1 to 1.5 times the molar amount. If it is less than this, unreacted double bonds remain, causing deterioration of weather resistance and coloring, and even if more hydrogen peroxide is used, no superiority is recognized and it may be an obstacle to post-reaction treatment. ..

The method of charging hydrogen peroxide is preferably such that it is gradually added dropwise in accordance with the reaction rate and the rate of reaction heat removal.

The concentration of hydrogen peroxide is not particularly limited and is 1
It can be used from 0 to 100%. Of these, about 30 to 70% of commercially available products are preferable from the viewpoints of easy availability, practical reaction rate and the like.

The type of organic solvent applied in the reaction is not particularly limited as long as it is a solvent that separates from water, and specific examples thereof include benzene, toluene, xylene, chloroform, dichloroethane, trichloroethane, perchlorethane and acetic acid. Mention may be made of methyl, ethyl acetate, butyl acetate, dibutyl ether, methyl tert-butyl ether and the like. From an industrial point of view, aromatic hydrocarbons such as toluene and xylene are preferable unless the reaction substrate is insoluble in the solvent.

The use of a non-polar solvent as the organic solvent is a particularly effective means when the reaction substrate has a high viscosity.

The amount of the solvent to be applied is not particularly limited as long as the viscosity of the reaction substrate decreases, but an appropriate amount is 0.5 to 4 times the weight of the reaction substrate.

The reaction temperature is about 40 to 90 ° C, preferably about 50 to 80 ° C.

At the above reaction temperature, the epoxidation reaction is usually completed in about 2 hours to 10 hours. The degree of progress of the reaction and the end time thereof can be known by the disappearance of hydrogen peroxide and the decrease of iodine value of the reaction substrate.

The reaction mixture obtained by the above reaction operation is washed with water to remove excess hydrogen peroxide and catalyst, and depending on the purpose, adsorbents such as activated carbon, clay, perlite and ion exchange resins are added for purification treatment. Can be given. afterwards,
The solvent is topped to obtain glycidyl esters containing a desired epoxycyclohexane ring.

[0027]

EXAMPLES The present invention will be described in detail below with reference to examples. In each example, the reaction rate was calculated from the iodine value of the reaction product. The epoxy production rate was calculated as a value obtained by subtracting the epoxy content of the reaction raw material from the epoxy content of the reaction crude and dividing this by the amount of double bonds reacted.
In this case, when the reaction does not proceed remarkably, a negative value may be shown due to hydrolysis of the glycidyl group in the raw material.

Production Example 1 1,4-Cyclohexanedimethanol 419.5 g
(2.91 mol) and tetrahydrophthalic anhydride 88
5.6 g (5.82 mol) was dissolved in 1500 g of toluene and heated at 120 ° C. for 5 hours. Next, 8 g (0.04 mol) of benzyltrimethylammonium chloride was dissolved, and 668 g (7.0 mol) of epichlorohydrin was dissolved in 8 parts.
The mixture was added dropwise at 0 ° C. over 7 hours, and heating and stirring were continued for 5 hours. 714 g of 50% aqueous sodium hydroxide solution (8.4
(Mol) at 80 ° C. for 3 hours under a reduced pressure to perform dehydration. The reaction product was washed with water and topped to obtain 1340 g (yield: 82%) of a product having an epoxy equivalent of 312 (theoretical value 280) and an iodine value of 90.5 (theoretical value 90.6).

Example 1 A 100 ml four-necked flask was charged with 14 g of the reaction raw material obtained in Preparation Example 1 (50 mmol of double bond), 14 g of toluene and 0.05 g of cetylpyridinium chloride and dissolved. Separately sodium tungstate 0.10 g
(0.3 mmol) and 0.15 g (1.5 mmol) of phosphoric acid were dissolved in 1 g of water, and pH was adjusted using sodium carbonate.
An aqueous solution adjusted to 3 is prepared and added to the above reactor. The temperature was raised to 70 ° C. with vigorous stirring, 3.4 g (60 mmol) of 60% hydrogen peroxide was added in portions, and the reaction was carried out for 5 hours. After completion of the reaction, the mixture was washed with 5% aqueous sodium sulfate and deionized water. The water layer was separated, the toluene layer was filtered to remove water, and topped with 15.1 g of a reaction crude product.
Got This has an iodine value of 5.2 and an epoxy equivalent of 18
It was 6. This is a reaction rate of 94%, epoxy production rate of 73
Equivalent to%.

Example 2 An epoxy equivalent of 19 was obtained by the same reaction as in Example 1 except that 0.08 g of ammonium tungstate was used as the oxidation catalyst.
0, 15.8 g of a reaction crude product having an iodine value of 2.5 was obtained. This corresponds to a reaction rate of 97% and an epoxy production rate of 74%.

Example 3 The same reaction as in Example 1 was carried out except that 0.05 g of benzyldimethylalkyl chloride (average carbon number = 13) ammonium chloride was used as a phase transfer catalyst to obtain an epoxy equivalent of 192,
16.2 g of a reaction crude product having an iodine value of 2.1 was obtained. This corresponds to a reaction rate of 97% and an epoxy production rate of 77%.

Example 4 Ammonium molybdate 0.50 g (2.8 mmol),
Trioctylmethylammonium chloride 0.20 g (0.
5 mmol), phosphoric acid 0.15 g (1.5 mmol),
Epoxy equivalent of 17 was reacted in the same manner as in Example 1 except that 4.3 g (75 mmol) of 60% hydrogen peroxide was used.
4, 13.3 g of a reaction crude product having an iodine value of 0.3 was obtained. This corresponds to a reaction rate of 99.7% and an epoxy production rate of 63%.

Comparative Example 1 Reaction was carried out in the same manner as in Example 1 except that the quaternary ammonium salt was not used, and the iodine value was 76.5 and the epoxy equivalent was 35.
13.9 g of a reaction crude product of 9 was obtained. This is a reaction rate of 16%,
This corresponds to an epoxy production rate of -12%.

Comparative Example 2 The reaction was carried out in the same manner as in Example 1 except that sulfuric acid was added and the pH of the aqueous phase was adjusted to 3 without using phosphoric acid.
15.9 g of a reaction crude product having 2.7 and an epoxy equivalent of 231 was obtained. This corresponds to a reaction rate of 72% and an epoxy production rate of 47%.

Production Example 2 1,6-hexanediol 343 as a dihydric alcohol
The target diglycidyl ester was prepared in the same manner as in Production Example 1 except that g (2.91 mol) was used. The obtained reaction product had an epoxy equivalent of 292 and an iodine value of 94.
It was 6.

Example 5 The reaction was carried out in the same manner as in Example 1 except that 13.3 g of the reaction raw material obtained in Production Example 2 (50 mmol of double bond) was used,
Reaction crude product having an iodine value of 2.6 and an epoxy equivalent of 174 14.
1 g was obtained. This is a reaction rate of 97%, epoxy production rate of 72
Equivalent to%.

Production Example 3 180 g of ethylene glycol as a dihydric alcohol
The target diglycidyl ester was prepared in the same manner as in Production Example 1 except that (2.91 mol) was used. The obtained reaction product had an epoxy equivalent of 252 and an iodine value of 109.
It was 8.

Example 6 Reaction was carried out in the same manner as in Example 1 except that 11.5 g of the reaction raw material obtained in Production Example 3 (amount of double bond was 50 mmol) was used.
Reaction crude 9.5 with iodine value 3.4 and epoxy equivalent 129
g was obtained. This is a reaction rate of 97%, epoxy production rate of 56%
Equivalent to.

Production Example 4 698 g of hydrogenated bisphenol A as a dihydric alcohol
The target diglycidyl ester was prepared in the same manner as in Production Example 1 except that (2.91 mol) was used. The epoxy equivalent of the obtained reaction product was 344, and the iodine value was 76.9.
Met.

Example 7 Reaction was carried out in the same manner as in Example 1 except that 16.4 g of the reaction raw material obtained in Production Example 4 (50 mmol of double bond) and 20 g of toluene were used, iodine value 3.2, epoxy. Equivalent 208
18.1 g of the reaction crude product of was obtained. This corresponds to a reaction rate of 95% and an epoxy production rate of 79%.

Example 8 Tetrahydrophthalic acid diglycidyl ester 13.9 g (double bond amount 46 mmol), toluene 15 g, sodium tungstate 0.2 g, trioctylmethylammonium chloride 0.20 g (0.5 mmol) as reaction raw materials. ), Phosphoric acid 0.15 g (1.5 mmol) and 60%
The reaction was performed in the same manner as in Example 1 except that 3.9 g (60 mmol) of hydrogen peroxide was used to obtain 8.7 g of a reaction crude product having an epoxy equivalent of 120 and an iodine value of 3.6. This is a reaction rate of 9
This corresponds to 7% and an epoxy production rate of 61%.

Production Example 5 The desired diglycidyl ester was prepared in the same manner as in Production Example 1 except that 628 g (4.37 mol) of 1,4-cyclohexanedimethanol was used as the dihydric alcohol. The epoxy equivalent of the obtained reaction product was 456, and the iodine value was 90.2.

Example 9 The same operation as in Example 1 was carried out except that 14.0 g of the reaction raw material (50 mmol of double bond) obtained in Preparation Example 5 and 20 g of toluene were used, and the iodine value was 3.2. , 15.7 g of a reaction crude product having an epoxy equivalent of 225 was obtained. This corresponds to a reaction rate of 95% based on iodine value and an epoxy production rate of 78%.

[0044]

Epoxidation by the method according to the present invention makes it possible to obtain the desired glycidyl esters having an epoxycyclosan ring under industrially advantageous conditions in high yield and high selectivity. .. This compound is useful as a sealing material for electronic parts and a coating film forming material suitable for paints for automobiles, which is effective as a measure against acid rain.

Claims (1)

[Claims] 1. A glycidyl ester having a cyclohexene ring represented by the general formula (I) is used in a water-organic solvent two-phase system, wherein (1) one or more oxidation catalysts selected from tungstic acid and molybdic acid. And (2) a long-chain alkyl group-containing quaternary ammonium salt or a long-chain alkyl group-containing phosphonium salt and (3) a phosphate anion in the presence of epoxidation with hydrogen peroxide, the general formula (II) A method for producing a glycidyl ester having an epoxycyclohexane ring represented by: [Chemical 1] [In the formula, R ¹ and R ² are the same or different and each represents a hydrogen atom or a methyl group, and A represents an alkylene group. n represents 0-5. ] [Chemical 2] IN FORMULA, R < ¹ >, R < ² >, A, N IS THE SAME AS GENERAL FORMULA. ]