JPH01186876A - Production of epoxidized (meth)acrylate - Google Patents

Abstract

PURPOSE:To readily obtain the title low-viscosity compound, having low odor and solubility in a wide range of resins and useful as ink, coating, etc., in good yield, by epoxidizing an acrylate or methacrylate compound with an oxidizing agent using piperidine as a polymerization inhibitor. CONSTITUTION:A cyclohexenyl (meth)acrylate compound which is a colorless and transparent liquid obtained by esterifying tetrahydrobenzaldehyde with (meth)acrylic acid, etc., used as an intermediate raw material for epoxy resins and expressed by formula I (R is H or CH3) is reacted and epoxidized in the presence of an oxidizing agent, such as peracetic acid or tert-butyl hydroperoxide, and a piperidine polymerization inhibitor, preferably in a solvent, such as ethyl acetate, at <=70 deg.C in the case of the peracetic acid and <=150 deg.C in the case of the tert-butyl hydroperoxide under ordinary pressure to afford the aimed compound, expressed by formula II and useful as a raw material for adhesives, coating agents, molding resins, etc., or modifying agents, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a method for producing an epoxidized (meth)acrylate compound.

(Meth)acrylate compounds can be easily homopolymerized or copolymerized with other unsaturated group-containing compounds in the presence of heat, ultraviolet rays, ionizing radiation, and radical polymerization initiators, and can also be used as intermediate raw materials for paint resins. is also useful.

(Prior Art) Various acrylic acid ester monomers have been known.

For example, monofunctional monomers such as methyl acrylate, ethyl acrylate, and 2-ethylhexyl acrylate, and polyfunctional monomers such as trimethylolpropane triacrylate and pentaerythritol triacrylate are generally known.

However, when monofunctional monomers are used in printing inks and paints, the odor of unreacted monomers after curing becomes a serious problem.

Furthermore, when polyfunctional monomers are used as diluents for paints and printing inks, they have to be used in large amounts relative to resins, which has the disadvantage that the properties of the resins are lost.

In this respect, the (meth)acrylate compound represented by (in the formula, R represents a hydrogen atom or a methyl group) obtained by epoxidizing with an oxidizing agent (in the formula, R represents a hydrogen atom or a methyl group) has a low viscosity, Moreover, it has low odor and solubility in a wide range of resins, and is useful as a raw material or modifier for inks, paints, adhesives, coatings, and molding resins.

However, it is known that this epoxidized (meth)acrylic ester represented by the symbol (It) is extremely susceptible to polymerization and is often caused by heat, light, and other factors during the manufacturing process, storage, and transportation. ing.

Conventionally, general polymerization inhibitors for acrylic monomers include quinones such as anthraquinone and p-quinone, their derivatives, nitrosos, amines such as paraphenylenediamine, and phenothiazine.

Metallic copper salts are known.

However, the epoxidized (meth)acrylic acid ester represented by Monka (II) does not have sufficient ability to inhibit polymerization, and there is a problem in that a decrease in yield due to polymerization occurs in the manufacturing process.

In addition, the epoxidized (meth)acrylic acid ester represented by Monana (II) has not yet been produced on an industrial scale, and until now there has been no prior art regarding polymerization inhibitors for this monomer. It is no exaggeration to say that there is no such thing at all.

(Problems to be Solved by the Invention) In view of the above-mentioned state of the prior art, the present inventors have attempted to overcome the above-mentioned problems by using an epoxidized (meta) As a result of extensive research into effective polymerization inhibitors for acrylic acid esters at high temperatures, the inventors discovered that amines, particularly piperidine, are highly compatible with the above-mentioned purpose, leading to the completion of the present invention.

(Structure of the Invention) The present invention is based on the method of epoxidizing a (meth)acrylate compound represented by -Monken (I) (in the formula, R represents a hydrogen atom or a methyl group) with an oxidizing agent. ) (In the formula, R represents a hydrogen atom or a methyl group) A method for producing an epoxidized (meth)acrylate compound characterized by the presence of piperidine as a polymerization inhibitor when producing the compound. be.

The method for producing the epoxidized (meth)acrylate compound of the present invention will be described in detail below.

The starting material for the reaction, a (meth)acrylate compound represented by the general formula (I) (in which R represents a hydrogen atom or a methyl group) [hereinafter referred to as cyclohexenyl (meth)acrylate], is a colorless and transparent liquid. It is used as an intermediate raw material for epoxy resin.

Industrially, it is produced by esterification of tetrahydrobenzaldehyde and (meth)acrylic acid or transesterification reaction of tetrahydrobenzaldehyde and (meth)acrylic acid ester. This manufacturing method was patented in 1986.
-108565 at a molar ratio of tetrahydrobenzyl alcohol/(meth)acrylic acid or (meth)acrylic acid ester from 1/10 to 10/1,
The reaction is carried out at a reaction temperature of 75 to 125° C. using p-toluenesulfonic acid, boron trifluoride, etc. as a catalyst.

In addition, the oxidizing agent used when epoxidizing cyclohexenyl (meth)acrylate to form the compound (II) may be any oxidizing agent as long as it can epoxidize unsaturated bonds, such as performic acid, peracetic acid, perpropionic acid, m-chloroperoxylic acid, etc. benzoic acid,
Examples include various hydroperoxides such as trifluoroperacetic acid, perbenzoic acid, tert-butyl hydroperoxide, cumyl hydroperoxide, tetralyl hydroperoxide, diisopropylbenzene hydroperoxide, and hydrogen peroxide. Can be done.

The oxidizing agent may be used in combination with a catalyst. For example, when an organic peracid is used, an alkali such as soda carbonate or an acid such as sulfuric acid may be used in combination as a catalyst.

Similarly, when using the above-mentioned various hydroperoxides, those having a known catalytic ability such as molybdenum hexacarbonyl can be used, and when using hydrogen peroxide, a mixture of tungstic acid and caustic soda can be used in combination.

When carrying out the reaction in batches, first charge a predetermined amount of sillerohexenyl (meth)acrylate into a 9 reaction vessel, dissolve the catalyst and stabilizer as necessary in this, and dropwise drop the oxidizing agent into this. Let's do it.

The reaction molar ratio between the oxidizing agent and cyclohexenyl (meth)acrylate is theoretically 1/1, but in the method of the present invention, it is in the range of 0.1 to 10, preferably in the range of 0.5 to 10. More preferably, the range is 0°8 to 1.2°.

When the molar ratio of the oxidizing agent and cyclohexenyl (meth)acrylate exceeds 10, it is preferable in terms of the conversion rate of cyclohexenyl (meth)acrylate, shortening the reaction time, and reducing loss due to polymerization of (meth)acrylate. However, a large amount of cost is required due to side reactions caused by excess oxidizing agent, selectivity of oxidizing agent, and recovery of unreacted oxidizing agent. There are drawbacks such as.

Conversely, if the molar ratio of the reaction between the oxidizing agent and cyclohexenyl (meth)acrylate is 0.1 or less, the selectivity of the oxidizing agent,
Although it is preferable in terms of conversion rate and suppressing side reactions caused by oxidizing agents, it requires loss due to polymerization of (meth)acrylate and a large amount of cost when recovering unreacted cyclohexenyl (meth)acrylate. There are drawbacks such as.

The reaction temperature is carried out below the upper limit so that the epoxidation reaction has priority over the decomposition reaction of the oxidizing agent. For example, when using peracetic acid, it is 70°C or less, and when using tert-butyl hydroperoxide, it is 150°C or less. preferable.

If the reaction temperature is low, it will take a long time to complete the reaction, so it is preferable to carry out the reaction at a temperature higher than the lower limit of 0° C. if peracetic acid is used, and 20° C. if tert-butyl hydroperoxide is used.

In addition, during the epoxidation reaction, a side reaction occurs in which the epoxy group is ring-opened with organic acids, alcohols, and water due to by-products from the oxidizing agent, so the temperature that reduces the amount of side reactions is set as described above. Select and implement from a temperature range.

The method according to the invention can be carried out under various pressures.

Although the invention generally operates under normal pressure, it can also be practiced under elevated or reduced pressure.

Moreover, the reaction of the present invention can also be carried out in the presence of a solvent. Reaction in the presence of a solvent has effects such as lowering the viscosity of the reaction crude liquid and stabilizing it by making the oxidizing agent more diluted.

Solvents used include aromatic compounds such as benzene, toluene, and xylene; halides such as chloroform, dimethyl chloride, carbon tetrachloride, and chlorobenzene;
Esterified products such as ethyl acetate and butyl acetate, ketone compounds such as acetone and methyl ethyl ketone, 1.2-
Ether compounds such as dimethoxyethane can be used.

The amount of solvent to be used is preferably 0.5 times the amount of cyclohexenyl (meth)acrylate.

If the amount is less than 0.5 times, there will be little stabilization effect by diluting the oxidizing agent, and conversely, if the amount is more than 5 times, the stabilizing effect will not improve much and it will cost a lot to recover the solvent. It is a waste because it requires .

The key point of the present invention is to add piperidine to prevent the starting material cyclohexenyl (meth)acrylate from polymerizing during the epoxidation reaction as described above.

Note that piperidine is the starting material cyclohexenyl (
It has a polymerization inhibiting effect on both meth)acrylate and the epoxide product which is the reaction product.

Note that piperidine may be used in combination with a conventionally used polymerization inhibitor.

Polymerization inhibitors used in combination include hydroquinone, P-methoxyphenol, 2,4-dimethyl-6-t-butylphenol, 3-hydroxythiophenol, α-nitroso-β-naph)-/1/, P-benzoquinone, Phene, thiazine, 2,5-dihydroxy-P-quinone, copper salt, etc. can be used, but hydroquinone and P-methoxyphenol are preferred from the viewpoint of stability.

The amount of polymerization inhibitor, mainly piperidine, used is 0 relative to the starting material cyclohexenyl (meth)acrylate.
．． 001-5.0% by weight, preferably 0.01-1.0
Weight%.

If the amount added is less than 0.001% by weight, the effect of inhibiting polymerization will be small, and conversely, if the amount added is 5.0% by weight or more, the effect will not improve and it will be wasted.

A polymerization inhibitor mainly consisting of piperidine is added by dissolving it in cyclohexenyl (meth)acrylate immediately before carrying out the epoxidation reaction.

Furthermore, adding a polymerization inhibitor when purifying the reaction crude liquid is effective for inhibiting polymerization.

The end point of the reaction is preferably confirmed by measuring the concentration of the remaining oxidizing agent and by gas chromatography.

After the reaction is completed, the epoxidation reaction crude liquid contains a solvent, a low boiling point substance,
It can be purified by removing unreacted raw materials, catalysts, etc., neutralizing it, and treating it with an adsorbent or ion exchange resin.

If necessary, it may be further purified by flash distillation, precision distillation, etc.

Purification treatments can be selected depending on the quality requirements of the final product.

If a final product of usable quality can be obtained without purification, it may be omitted.

Particularly when using an organic acid as an oxidizing agent, removing low-boiling components without neutralizing the crude reaction solution will result in large losses due to polymerization of (meth)acrylate, so neutralize the low-boiling components before removing them. is preferable.

Examples of alkaline aqueous solutions used for neutralization include NaOH
%KOH, K Co , Na2 C0, Na
Aqueous solutions of alkaline substances such as HCO, KHCO, NH3, etc. can be used.

The concentration used can be freely selected from a wide range.

From the viewpoint of liquid separation, NaCO3 aqueous solution, NaHCO
3. Preferably, an aqueous solution is used.

After neutralization, if low-boiling components are removed without washing with water and the bottom liquid is made into a product, neutralized salts will remain in the product, so it is preferable to wash with water after neutralization.

Neutralization and water washing at 10-90°C, preferably 10-50°C
It is best to perform this in the temperature range of ℃.

In order to remove low-boiling components from the reaction crude liquid that has been neutralized or washed with water, it is preferable to use a thin film evaporator or the like after adding a polymerization inhibitor.

The material of the apparatus to which the method of the present invention can be applied is preferably stainless steel, glass-lined steel, etc., but ordinary iron materials may also be used.

EXAMPLES The effects of the present invention will be specifically explained below with reference to Examples, but the present invention is not limited to these Examples.

[Example 1] and [Comparative Examples 1 to 6] Table 1 shows the results of comparing the polymerization inhibition ability of a mixed solution of 40% cyclohexenyl methacrylate and 60% tertiary and quaternary polycyclohexyl methyl methacrylate obtained by epoxidizing this. show.

The temperature was 130° C. in all cases, and the atmosphere was air in all cases except for Comparative Example 1, in which nitrogen was used.

Moreover, this composition is close to the liquid composition when the reaction crude liquid is leaked from a thin film evaporator.

As is clear from Table 1, piperidine has a remarkable polymerization inhibiting effect.

The values in Table 1 are those obtained when 11,000 pp of polymerization inhibitor was added at a temperature of 130°C.

[Example 2] and [Comparative Example 7] Table 2 shows the results of comparing the polymerization inhibition ability for 3,4 epoxycyclohexylmethyl methacrylate at a temperature of 160° C. with and without the addition of a polymerization inhibitor.

Table 2 (blank below) [Example 3] 300 g of cyclohexenyl methacrylate was placed in a reactor with an internal capacity of 2.5 j and equipped with a cooling jacket.

After adding 600 g of ethyl acetate and 2.8 g of piperidine, 478 g of a 30% solution of peracetic acid in ethyl acetate was added dropwise over 2 hours.

During the dropping, the temperature of the hot water flowing through the jacket was adjusted to be slightly higher than 40°C so that the reaction temperature was 40°C.

After the dropwise addition was completed, the reaction temperature was maintained at 40° C. for 5 hours to complete the reaction.

At this time, the concentration of peracetic acid in the reaction crude liquid was 1% or less.

1378 g of the reaction crude liquid was mixed with 6% Na 1 (CO3 aqueous solution 3
Washed with 583g.

After liquid separation, the upper layer was washed with 1378 g of water, and after separation, low-boiling components of the upper layer liquid were removed.

A thin film evaporator was used to remove low boiling point components, the amount of piperidine added was 500 ppm, and the pressure was 20 Torr.

The test was carried out at a temperature of 90 to 95°C.

Commercialization uses a thin film evaporator at a pressure of 5 Torr.

The reaction was carried out at a temperature of 90 to 95°C to remove cyclohexenyl methacrylate, which is an unreacted raw material.

The yield was 93% based on cyclohexenyl methacrylate.

Claims (1)

[Claims] General formula (I) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R represents a hydrogen atom or a methyl group) A (meth)acrylate compound is epoxied with an oxidizing agent. The general formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R represents a hydrogen atom or a methyl group) When producing a compound represented by the following, piperidine is present as a polymerization inhibitor. A method for producing an epoxidized (meth)acrylate compound, characterized by: