JPH0959269A - Production of glycydyl methacrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound for powder coating, adhesives, curing agents in high yield by reacting allyl methacrylate with hydrogen peroxide in the presence of a solid catalyst in a solvent, separating the catalyst and washing the reaction product with water or an alkali aqueous solution and distilling the product. SOLUTION: Allyl methacrylate is reacted with dropped hydrogen peroxide at 60 deg.C in one or more kinds of solvents selected from methanol and acetone or methanol, methylethyl ketone, etc., in the presence of a solid catalyst comprising titanosilicate, etc., having MFI crystalline structure and prepared by adding tetrapropylammonium hydroxide aqueous solution to tetraethyl orthosilicate and heating these components at 210 deg.C in an autoclave and carrying out baking treatment of these components at 550 deg.C and the reactional liquid is filtered to remove a solid catalyst and the solution is washed with water or alkali aqueous solution and distilled to provide the objective glycidyl methacrylate useful as a raw material for powder coating, an adhesive, a curing agent, a modifier, etc., in a high yield.

Description

Detailed Description of the Invention

[0001]

Industrial Field of the Invention The present invention produces glycidyl methacrylate, which is an important industrial raw material having a wide range of uses such as powder coating raw materials, adhesives, curing agents, and modifiers, without containing chlorine compounds. It is about how to do it.

[0002]

2. Description of the Related Art Glycidyl methacrylate having a methacryloyl group and an epoxy group in its molecule is a highly reactive compound and is used as a reactive monomer for various purposes. Glycidyl methacrylate is known to be produced by a reaction of methacrylic acid or an alkali metal salt thereof with epichlorohydrin, but there is a problem that epichlorohydrin used as a raw material or a chlorine compound as a by-product remains in the product. In order to avoid this problem, various attempts have been made to convert the process to a process using no chlorine source, and a method using glycidol instead of epichlorohydrin, a method of epoxidizing allyl methacrylate, etc. are known. Among them, the method of epoxidizing allyl methacrylate using hydrogen peroxide, which is a relatively inexpensive oxidizing agent, has been attempted as a promising method.

For example, JP-A-5-92962 discloses a method of epoxidizing a phase transfer catalyst in the presence of a molybdate or tungstate of an alkali metal which is a homogeneous catalyst. In addition, the reaction rate is very low, and the separation and recovery of the catalyst is not easy, and it has not reached a practical level. On the other hand, in recent years, a method using a solid catalyst which can be easily separated after the reaction has been actively developed. For example, JP-A-61-183275 discloses a method of epoxidizing allyl methacrylate with hydrogen peroxide using a titanosilicate catalyst which is a silicon oxide-titanium oxide synthetic zeolite having an MFI structure.

[0004]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention As a result of detailed investigation of the above-mentioned method using a titanosilicate catalyst, the present inventors have found that the reaction itself proceeds well and gives glycidyl methacrylate with excellent reaction results. However, when recovering glycidyl methacrylate from the reaction solution obtained by filtering the catalyst, physical and chemical losses due to various factors are large, and the yield at the time of the reaction is significantly reduced. Was found to have. In the epoxidation reaction with hydrogen peroxide using a titanosilicate catalyst, the presence of a solvent is indispensable in order to proceed the reaction favorably, and it is generally known that methanol is suitable as a reaction solvent ( Japanese Patent Publication No. 4-5028). However, in the system of allyl methacrylate, the solution after the reaction is uniform even when cooled to around room temperature, so in order to take out glycidyl methacrylate from the reaction solution, a solvent such as methanol and a diluent for hydrogen peroxide are distilled. Therefore, it is necessary to remove water generated in the reaction. This requires a large amount of energy and causes a cost increase. Moreover, it is difficult to separate methanol and water by simple distillation, and there is a problem that a large amount of water is recycled and accumulated in the reaction system without being discarded.

A further difficult problem to solve is the problem of polymerization that occurs during distillation. Glycidyl methacrylate has a very high polymerization activity, so a radical polymerization inhibitor is usually added for distillation, but even if such a polymerization inhibitor is added to this system, the effect is small and However, since a large amount of the polymer remains as a residue in the kettle, the ratio of glycidyl methacrylate produced in the reaction that can be actually taken out is very small. As described above, since this method uses relatively expensive allyl methacrylate as a raw material, it is industrially indispensable to take out glycidyl methacrylate from the reaction solution in a higher yield. The subject of the present invention is a solid catalyst, in particular, in a method for producing glycidyl methacrylate by epoxidizing allyl methacrylate with hydrogen peroxide using a titanosilicate catalyst, physical and physical steps in each step, and high yield without chemical loss. Is to provide a method for obtaining glycidyl methacrylate.

[0006]

Means for Solving the Problems As a result of intensive investigations aimed at solving the above-mentioned problems, the present inventors have found that a reaction solution obtained by carrying out a reaction using a mixture of methanol and a ketone as a reaction solvent is treated with a catalyst. It was found that it is possible to recover glycidyl methacrylate in a high yield without causing problems such as polymerization by filtering, washing with water or an aqueous alkali solution and then distilling, and completed the present invention. It is a thing. Hereinafter, the present invention will be described in detail.

As the solid catalyst used in the present invention, various crystalline substances containing titanium atoms in the crystal lattice are used.
TS-1 with FI structure, TS-2 with MEL structure,
Ti-β having a zeolite β structure and the like can be exemplified, but among them, a titanosilicate catalyst (TS-1) having an MFI structure is most preferably used. This titanosilicate catalyst is prepared by a known method (for example, USP 4,4
No. 10,501) can be used. The amount of the titanosilicate catalyst cannot be generally specified because the activity of the catalyst changes depending on the amount of Ti contained in the crystal, but usually, as the concentration in the reaction mixture,
A range of 0.1 to 20% by weight is suitable. More preferably, it is in the range of 0.5 to 10% by weight.

A mixed solvent of methanol and a ketone is used as a reaction solvent, and the ketone is preferably acetone or methyl ethyl ketone, more preferably methyl ethyl ketone. The mixing ratio of methanol and ketone in the mixed solvent is 0.1: 1 in terms of methanol / ketone weight ratio.
It is preferably in the range of 10: 1. If the amount of methanol in the mixed solvent is too large, the proportion of glycidyl methacrylate distributed in the aqueous layer after alkali washing increases, so a more preferable range of the mixing ratio is 0.2: 1 to 2: 1.
Range. In the present invention, as long as the above range is maintained, addition of solvents other than alcohols and ketones is not hindered. There is a suitable range for the amount of alcohol and ketone mixture used. If the amount of the mixture of alcohol and ketone is too small, the reaction mixture is separated into an organic layer and an aqueous layer even at the reaction temperature, and a secondary reaction such as diol formation due to the hydrolysis reaction of glycidyl methacrylate mainly proceeds in the aqueous layer. This is not preferable because the contribution of the reaction becomes large. On the other hand, if the amount of the mixture of alcohol and ketone is too large, the reaction rate decreases and the concentration of glycidyl methacrylate produced in the reaction mixture becomes low, and the energy cost for removing a large amount of solvent becomes too large. Not economical. The amount of the alcohol and ketone mixture is preferably such that the liquid phase of the reaction mixture excluding the insoluble catalyst is homogeneous at the reaction temperature and does not separate into the organic layer and the aqueous layer. The amount of such a mixture of methanol and ketone may vary depending on the molar ratio of allyl methacrylate and hydrogen peroxide, etc., but is usually 5 to 5 with respect to the total amount of the reaction mixture excluding the catalyst.
It is selected from the range of 80% by weight, more preferably 20 to 50% by weight.

There is no particular limitation on the hydrogen peroxide used, and it is 30
An aqueous solution of hydrogen peroxide having a concentration such as wt%, 60 wt% or 90 wt% can be used. The amount of hydrogen peroxide to be added can be used in excess with respect to allyl methacrylate in a molar ratio, or allyl methacrylate can be used in excess. If hydrogen peroxide is used in excess,
Although the concentration of the reactants in the reaction mixture can be relatively reduced, it has the merit of reducing the cost of separating and purifying the product, but the reaction takes a long time and contributes to side reactions such as the formation of diol by the hydrolysis of glycidyl methacrylate. Is large and often gives unfavorable results in the whole process. On the other hand, when allyl methacrylate is used in excess, it is necessary to remove and collect the excess allyl methacrylate later, but in addition to the advantages such as high reaction rate and relatively small generation of by-products, hydrophobic The more preferable results are obtained such that the two-layer separation at the time of alkali cleaning due to the residual highly soluble allyl methacrylate is facilitated and the transfer of glycidyl methacrylate to the aqueous layer is suppressed. Considering these facts, the preferable range of the allyl methacrylate / hydrogen peroxide molar ratio is 1.1 to 5, more preferably 1.5 to 3.

The present invention preferably employs a system in which a catalyst, a mixture of methanol and a ketone, and allyl methacrylate are placed in a reactor such as a tank-type stirring reactor and hydrogen peroxide is added to the reactor to start the reaction. On the other hand, a method in which a catalyst, a mixture of methanol and ketone, and hydrogen peroxide are placed in a reactor such as a tank-type stirring reactor and allyl methacrylate is added to start the reaction is preferable because side reactions occur to a degree that cannot be ignored. Absent. It is also possible to fix the catalyst in a reactor such as a tank-type stirring reactor and continuously introduce a mixture of methanol and ketone, allyl methacrylate and hydrogen peroxide into the reactor and simultaneously withdraw it. The reaction temperature is 30 to 12
The range of 0 ° C is preferable, and more preferably 50-80 ° C.
Range. When the reaction temperature is lower than the above range, the reaction rate is slow and not practical, and when it is higher than the above range, the contribution of side reaction becomes large. Since the reaction for producing glycidyl methacrylate is an exothermic reaction, it is preferable to remove the heat of reaction by an appropriate method in order to control the reaction temperature within a certain range.

The point at which the reaction is completed has a great influence on the yield during distillation and is one of the factors that determines the economic efficiency of the process. Terminating the reaction at a time when the conversion rate of hydrogen peroxide is not sufficient is not preferable because the residual hydrogen peroxide has to be discarded and the ratio of hydrogen peroxide to the cost increases. However, it has been found that when the conversion rate of perhydrogen is approached to 100% as much as possible, the contribution of the side reaction of glycidyl methacrylate formed becomes large, resulting in polymerization at the time of distillation, which is not a good measure.
Therefore, as a preferable end point of the reaction, the conversion rate of hydrogen peroxide, which is the limiting substance, can be selected to be 80% or more and 99% or less. It is more preferably 90% or more and 98% or less. The end of the reaction is to remove the catalyst from the reaction solution,
Alternatively, it can be performed by cooling the reaction solution to room temperature or lower.

The reaction solution from which the catalyst has been removed by filtration,
Washing is performed by adding water or an alkaline aqueous solution. As the type of alkali, if it does not easily react with the generated glycidyl methacrylate and is acceptable in terms of cost,
The aqueous solution can be arbitrarily selected from substances having a pH value of 7 or more. That is, it is a substance typified by sodium hydroxide, sodium hydrogen carbonate, sodium acetate, and the like. The concentration of alkali in the aqueous solution is
The range is 0 to 10% by weight including water. If an excessively high concentration of alkali is used, it is necessary to be careful because an undesirable side reaction such as hydrolysis of the ester portion of glycidyl methacrylate may occur. On the other hand, in the case of pure water containing no alkali, although it has the same effect as alkali, cleaning with a relatively large amount of water is necessary to obtain the same effect. Therefore, a dilute aqueous alkaline solution is preferable. Washing can be performed according to a known method. That is, it can be carried out batchwise, continuously with a device such as a mixer-settler, or it is possible to use a countercurrent extraction device.

There is an appropriate range for the amount of water or alkaline aqueous solution used for washing. That is, when the amount of washing water is small, the effect becomes small, and conversely when it is too large, the distribution of glycidyl methacrylate into the aqueous layer cannot be ignored, and the amount cannot be recovered, which is an advantage of suppressing polymerization during distillation. Will be offset. Also, considering that the water layer is discarded as wastewater, it is desirable to reduce the amount of drainage as much as possible. When performing batch cleaning, it is possible to reduce the total amount by cleaning a predetermined amount of water or an aqueous alkaline solution in several times. Further, the required amount of washing water greatly changes depending on the composition of the reaction solution, and as the hydrogen peroxide conversion rate approaches 100%,
A large amount of washing with water is required to obtain a good recovery rate of glycidyl methacrylate by distillation. Therefore, the amount of washing water can be suppressed to a low level by terminating the reaction within the range of the above-mentioned conversion ratio of perhydrowater. For example, 1 to 20% by weight based on the reaction solution after filtration
The effect can be sufficiently obtained by washing with water or an alkaline aqueous solution.

[0014]

EXAMPLES The present invention will be described below in detail with reference to examples, but the contents of the present invention are not limited in any way by these examples. Reference Example (Method for preparing titanosilicate catalyst) Tetraethyl orthosilicate (375 g) and tetraethyl orthotitanate (10.3 g) were placed in a 3 L four-necked separable flask and placed under a nitrogen stream using a dropping pump to obtain 2
648 g of a 0 wt% tetrapropylammonium hydroxide aqueous solution was added dropwise at a rate of 5.4 g / min. During the addition, the temperature of the reaction solution was adjusted to be constant at 20 ° C.
After completion of the dropwise addition, stirring was continued for a while, and the hydrolysis was allowed to proceed completely. Then, the reaction temperature was heated to 80 ° C., and ethanol produced by the hydrolysis was distilled off from the reaction solution to obtain a transparent sol. To the obtained sol, 290 g of distilled water was added, and the total weight of the solution was 885 g, which was filled in a 3 L autoclave made of SUS316 at a filling rate of 30%. After substituting the gas in the autoclave with nitrogen, it was sealed and heated to 170 ° C. for 2 days, heated to 210 ° C., kept at 210 ° C. for another 2 days, and then cooled to room temperature. The liquid containing a white solid was centrifuged at 3000 rpm for 20 minutes using a centrifuge to separate a substantially transparent supernatant liquid and white titanosilicate particles. The white titanosilicate particles obtained were washed with distilled water, dried, and calcined in an electric furnace at 550 ° C. for 6 hours in air to obtain 91.7 g of a titanosilicate catalyst. The Si / Ti ratio in the obtained crystalline titanosilicate was 66 as determined by a fluorescent X-ray method.

Example 1 330 g (2.62 mol) of allyl methacrylate, 50 g (1.56 mol) of methanol and 5 methyl ethyl ketone
0 g (0.69 mol), and 12.4 g of the titanosilicate catalyst prepared in the above Reference Example were charged into a flask equipped with a stirrer, a thermometer, and a reflux condenser, and then 59.4 g of 60 wt% hydrogen peroxide solution. (1.05 mol, starting material allyl methacrylate: hydrogen peroxide molar ratio = 2.5: 1) was added dropwise at a reaction temperature of 60 ° C. over 1.5 hours. After stirring was continued for another 10 minutes after the completion of the dropwise addition, the catalyst was filtered to terminate the reaction. The hydrogen peroxide conversion rate was 93.7%, and the residual amount of allyl methacrylate in the reaction solution after filtration was 201.4 g.
(1.60 mol), the amount of glycidyl methacrylate produced is 1
It was 23.8 g (0.87 mol). This reaction solution 4
To 62.7 g, 18.3 g of a 1.0 wt% sodium hydroxide aqueous solution (4.0 wt% of the reaction solution) was added, and the mixture was stirred at room temperature and then left to stand to separate into two layers (organic layer 422). .9
g, aqueous layer 58.1 g). Allyl methacrylate contained in the organic layer is 198.9 g, and glycidyl methacrylate is 1
22.2 g, and the recoveries are 98.7% and 9 respectively.
It was 9.0%. The organic layer was placed in a 500 ml round-bottomed flask, 0.83 g (0.2 wt% of the solution) of the polymerization inhibitor Antage W400 was added, and simple distillation was performed under reduced pressure.
First, add methanol and methyl ethyl ketone to 240 mm
Hg was distilled off at a bottom temperature of 65 ° C, and then allyl methacrylate was distilled off at 40 mmHg and a bottom temperature of 75 ° C.
Allyl methacrylate containing glycidyl methacrylate was used as the initial distillation, and the pressure was changed from 35 mmHg to 3 mmH by distillation.
3gH after changing to g and acquiring at bottom temperature 70 ℃
g, and 90.8 g of glycidyl methacrylate were distilled off at a steam temperature of 65 ° C. A total of 116.9 g of glycidyl methacrylate was recovered by combining 26.1 g contained in the initial distillation (distillation yield: 96.0%). The remaining pot is 10.0g
(2.4% by weight), the viscosity was low and polymerization was not observed. The recoveries of allyl methacrylate and glycidyl methacrylate from the reaction solution after catalyst filtration were 97.6% and 95.0%, respectively, and almost quantitative recovery was possible. The results are shown in Tables 1 and 2.

Examples 2 to 5 As in Example 1, cleaning was carried out under the conditions shown in Table 1. 0.2% by weight of the polymerization inhibitor Antage W4 in the organic layer
Table 2 shows the result of distillation by adding 00.

Comparative Example 1 (without washing with alkaline water) A reaction solution was prepared in the same manner as in Example 1, filtered through a catalyst, and distilled without washing with an alkaline aqueous solution. However, 0.2% by weight of Antage W400 was added as a polymerization inhibitor. Polymerization occurred when the glycidyl methacrylate fraction was obtained, and the distillation yield calculated from the recovered glycidyl methacrylate was 37.1%, which was very small. The amount of the polymer remaining in the kettle was very large at 80.1 g. The results are shown in Tables 1 and 2.

Comparative Example 2 (Hydrogen Peroxide Conversion> 99%) The same as Example 1 except that the hydrogen peroxide conversion was raised to 99.4% by stirring for 30 minutes after the completion of hydrogen peroxide addition. The solution in which the reaction solution was prepared was washed with alkali in the same manner as in Example 1. As shown in the results in Table 2, polymerization occurred during distillation and the distillation yield was as low as 85%.

[0019]

[Table 1]

[Table 2]

Front page continuation (72) Inventor Takanobu Okamoto 22 Wadai, Tsukuba City, Ibaraki Mitsubishi Gas Chemical Co., Ltd.

Claims (4)

[Claims] 1. A method for producing glycidyl methacrylate by reacting allyl methacrylate with hydrogen peroxide in the presence of at least one solvent and a solid catalyst, wherein the catalyst is separated from the reaction solution, and the solution is water or an aqueous alkali solution. A method for producing glycidyl methacrylate, which comprises recovering glycidyl methacrylate by washing with water and then distilling. 2. The method for producing glycidyl methacrylate according to claim 1, wherein the solid catalyst is titanosilicate having an MFI crystal structure. 3. The method for producing glycidyl methacrylate according to claim 1, wherein the solvent is a mixture of methanol and a ketone. 4. The method for producing glycidyl methacrylate according to claim 1, wherein the solvent is methanol and acetone or methanol and methyl ethyl ketone.