JPS6344151B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing glycidyl vinyl ether, and more specifically, to a method for producing glycidyl vinyl ether in good yield through a three-step reaction using ethylene chlorohydrin and epichlorohydrin as raw materials. Glycidyl vinyl ether (hereinafter referred to as GVE) is a useful substance that can be used in various reactions because it shares an olefinic double bond and an epoxy group in its molecule. Furthermore, since the olefinic double bond in GVE is non-allylic, it behaves differently from allyl glycidyl ether. For example, radical copolymerization using double bonds, particularly copolymerization with fluorefin, is possible, and in this case a reactive polymer having epoxy groups as active sites can be obtained. Conversely, if ionic polymerization is performed using epoxy groups, a polymer having double bonds as active groups can be obtained. Other uses include processing agents and hardening agents for fillers in rubber and plastics. The following methods of producing GVE have been conventionally known. However, method (A) uses expensive glycidol.

It has many disadvantages as an industrial production method, such as the use of [Formula] as a raw material and the necessity of using toxic organic mercury as a catalyst. Although method (B) has the advantage of using cheaper starting materials compared to method (A), the reaction yield in each step is low, and the third step in particular requires only a small amount of laboratory material. Although it can be used as a synthetic method, the yield is at most 5.
%, the stability of the reaction is low, and furthermore, it is difficult to control the reaction because it generates a very large amount of heat. The present inventor has achieved a method with good yield from inexpensive raw materials.
In order to provide a means to industrially manufacture GVE,
Various researches were conducted. As a result, we obtained the following interesting findings. In other words, we have obtained new knowledge that by appropriately modifying the method (B) above, the reaction can be carried out smoothly and the reaction yield can be improved to about 25% or more. be. In particular, in the third reaction, diluting the alkali (NaOH etc.) with a specific solvent,
It is advantageous to take measures to shorten the residence time of the raw materials and the desired product in the reaction system.
By adding the raw materials little by little into the dilute alkali solution and distilling off the target product from the reaction system, consumption of highly reactive epoxy groups can be suppressed. Thus, the present invention has been completed based on the above knowledge, and uses ethylene chlorohydrin and epichlorohydrin as starting materials to produce the following (1) to (3).
In producing GVE through the three-step reaction,
The reaction of (3) is carried out at a reaction temperature of 150 to 200°C in a solvent that can at least partially dissolve the alkali as a HCl removing agent at the reaction temperature and has a boiling point of 160 to 200°C.

[Formula] is added and supplied to the reaction system little by little, and the reaction is carried out while distilling the product from the reaction system.
This provides a method for manufacturing GVE. The method of the present invention consists of the following three steps of reactions (1) to (3). In the present invention, the reaction (1) can be carried out under various operations and conditions. Usually, it is desirable to carry out the process in the presence of an acid catalyst, such as concentrated sulfuric acid,
Examples include solid acids such as silica and alumina, polymers having strong acid groups such as sulfonic acid groups, and P-toluenesulfonic acid. Reaction temperature is 50-150
The temperature is selected from the range of 60 to 140°C, and the preferred range varies slightly depending on the type of acid catalyst used. For example, in the case of concentrated sulfuric acid catalyst, 80 to 140℃,
Preferably it is about 100 to 130°C, and in the case of silica/alumina catalyst, it is 50 to 100°C, preferably 60 to 90°C.
Relatively low temperatures on the order of degrees Celsius may be employed. If the reaction temperature is too high, side reactions such as carbonization, polymerization, and dimerization will proceed; if the reaction temperature is too low, the reaction rate will be slowed down. Since the reaction (1) is an exothermic reaction, it is desirable to appropriately cool the reaction system so that the reaction temperature does not exceed the above-mentioned preferred range. The reaction (1) is preferably carried out in excess of ethylene chlorohydrin, and a molar ratio of 1.5 moles or more, preferably about 2 to 4 moles of ethylene chlorohydrin per mole of epichlorohydrin is usually employed. If the proportion of ethylene chlorohydrin is too small, dimerization and polymerization of epichlorohydrin will increase, and if it is too large, it will take time and effort to recover unreacted ethylene chlorohydrin. The reaction time may be relatively short, and can be further shortened by increasing the reaction temperature. If the reaction is carried out for an excessively long time, there is a marked tendency for side reactions to occur. Therefore, the reaction time is usually about 2 hours or less, and preferably from the range of about 30 minutes to 1.5 hours. In the present invention, it is desirable that the reaction (1) be completed in as short a time as possible, as described above. Therefore, in a preferred embodiment, it is desirable to immediately apply reaction termination means upon completion of the reaction (1). There are various methods for stopping the reaction, such as cooling the reaction system to a temperature lower than the reaction temperature, but a method of removing the acid catalyst from the reaction system can be preferably employed. For example, in the case of a concentrated sulfuric acid catalyst, the reaction can be stopped smoothly and advantageously by neutralizing the reaction system using a powdered alkali or aqueous alkali solution such as sodium hydroxide or potassium hydroxide. In this case, if an aqueous alkali solution is used, it becomes difficult to separate water and unreacted ethylene chlorohydrin, so it is preferable to use a powdered alkali. Furthermore, in the case of a solid acid catalyst such as silica/alumina, the reaction can be stopped by stopping stirring of the reaction system, cooling it, removing the solid acid, etc. The reaction (1) can normally be carried out without using an inert solvent as a reaction medium, but of course any suitable reaction medium may be used. In addition, it is also possible to appropriately devise the stirring of the reaction system, the order of introduction of reaction raw materials into the reaction system, and the like. For example, a suitable method is to charge ethylene chlorohydrin and epichlorohydrin in advance into a reaction vessel, stir them to make them homogeneous, and then dropwise add concentrated sulfuric acid at room temperature. In this case, since the reaction is accompanied by significant heat generation, it is important to control the addition rate so that the reaction temperature does not rise too much. In the reaction (2) of the present invention, the first stage product (

[Formula] (hereinafter referred to as intermediate) is separated and used as a raw material after purification or as a crude product. and,
In reaction (2), the intermediate is reacted with an alkali as an HCl removing agent. As the alkali in the reaction (2), alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are usually suitably used, but alkali carbonates and milk of lime may also be used. The reaction (2) usually involves dissolving an alkali as a HCl removal agent and producing

Preferably, the process is carried out using a medium that does not dissolve the formula (hereinafter referred to as intermediate). For example, water is suitable as a medium for reaction (2). The reaction temperature varies depending on the alkali and medium used, but it is usually 50℃ or higher.
It is selected from the range of less than 150℃, and considering the reaction rate and stability of the intermediate, 80 to 110
The temperature is preferably about ℃. When using water as a medium, 90
Reaction temperatures of the order of ~105°C are particularly preferred. The alkali in the reaction (2) is 1 mole of intermediate.
Equivalent is the stoichiometric amount, and it is usually desirable to use an excess of alkali, but since a large excess of alkali causes ring opening of the glycidyl group formed, it is usually necessary to use an alkali to maintain the pH within the range of 7.5 to 10.5. A subsequent addition method is advantageous. The reaction time is not particularly limited, but usually about 30 minutes to 3 hours is sufficient. In the present invention, the intermediate obtained in the reaction (2) and an alkali are reacted in a specific solvent at a specific reaction temperature and by a specific reaction operation according to the reaction formula (3). This is very important. and,
When water is used as a medium in the reaction (2), the intermediate is separated from the aqueous phase, purified by distillation or the like if necessary, and used as a raw material for the reaction (3). As the alkali as the HCl removing agent in the reaction (3), an alkali metal hydroxide is used, and sodium hydroxide or potassium hydroxide is preferably used. The reaction (3) is
The alkali as HCl agent can be at least partially dissolved under the reaction temperature and the boiling point is 160~200℃
is carried out in a solvent. Examples of the solvent include aprotic polar organic solvents, such as glycol ethers and dimethyl sulfoxide. In particular, diethylene glycol dimethyl ether is a suitable solvent. Reaction temperature is 150-200
It is selected from the range of 160 to 180 degrees Celsius. Thus, the reaction (3) is carried out while adding the intermediate to the reaction system little by little to react with the alkali and distilling off the desired product, GVE, from the reaction system. Although the alkali may also be added and supplied to the reaction system little by little, it is usually preferable to dissolve or disperse a predetermined amount of the alkali in a specific solvent, and then add and feed the intermediate little by little. Dissolution or dispersion of the alkali in the specific solvent can be easily achieved by generally heating the alkali together with the specific solvent, preferably by heating under solvent reflux. By maintaining the alkali solution or dispersion at the above reaction temperature and dropping the intermediate thereto, (3)
The reaction can proceed smoothly and advantageously. Of course, a stirring means may be used in combination to promote dissolution or dispersion of the alkali in the specific solvent or to promote the reaction (3). Reaction (3) is usually carried out in an excess of alkali. The reaction (3) is usually preferably carried out under reflux of a specific solvent. In the reaction (3), the rate at which the intermediate is added to the reaction system is not particularly limited as long as it is added in small amounts, but in the case of 10 reaction vessels, it is usually about 0.1 to 50 mol/min, preferably 3 to 20 mol. /minute is adopted. The rate of addition and supply can be changed as appropriate depending on the alkali concentration, reaction temperature, degree of stirring of the reaction system, etc., and it is important to adjust it so that a stable reaction can be performed without causing flattening, insufficient distillation, etc. It is. At this time, in order to supplement the solvent that is entrained and distilled off together with the target GVE as described later, the specific solvent may be added and supplied to the reaction system together with the intermediate in small amounts. Furthermore, it goes without saying that the alkali may be supplied in the form of a specific solvent solution, which is suitable when the reaction (3) is carried out continuously. The target GVE produced in the reaction (3) is distilled off from the reaction system as the reaction progresses. PurposeGVE
Distillation from the reaction system can be carried out smoothly and advantageously by employing the reaction temperature as described above, preferably by carrying out the reaction under reflux of the specific solvent, and usually some of the specific solvent is also removed. It is distilled off along with GVE. Such concomitant distillation of the specific solvent can facilitate smooth and advantageous distillation of the target GVE from the reaction system. Most of the specific solvent is then refluxed and returned to the reaction system. Regarding the removal of GVE,
The most desirable form is to maintain the lower part of the reflux column at a temperature close to the boiling point of the specific solvent, so that GVE is sufficiently distilled from the reaction system.
The temperature from the middle to the upper part of the reflux column is maintained at a temperature near the boiling point of GVE, and the specific solvent is refluxed and GVE is distilled off, so that conditions are maintained such that GVE and specific solvent can be efficiently separated. It is essentially important to maintain a balance between the rate of GVE distillation from the top of the column, the reaction rate within the reaction vessel, and the rate of addition of intermediates into the reaction system. That is, if the rate of distillation of GVE from the top of the column is too slow compared to the rate of evaporation of GVE from within the reaction system and the specific solvent, flooding will occur within the column, resulting in an increase in pressure within the system. There is a risk of temperature rise and even bumping or runaway reaction. On the other hand, if it is too fast,
GVE and specific solvents are not separated efficiently,
As the loss of the specific solvent increases, the concentration of the reactant in the reaction system increases and the temperature increases due to the viscosity of the system, increasing side reactions and creating a risk that the reaction will run out of control. As mentioned above, the GVE distilled from the reaction system (3) is
It is separated from the accompanying specific solvent, subjected to dehydration treatment if necessary, and then purified by vacuum distillation or the like. Separation from the specific solvent can be performed by operations such as extraction with water, and dehydration treatment can be performed by using sodium sulfate, monocular sieves, and the like. Next, embodiments of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations. Example 1 322 g (4 mol) of ethylene chlorohydrin and 185 g (2 mol) of epichlorohydrin are charged into a 500 ml four-necked flask equipped with a reflux tube, dropping funnel, thermometer, and stirrer. While stirring the contents, carefully drop 5 ml of concentrated sulfuric acid from the dropping funnel, causing intense heat generation and reaction (1) to proceed. The temperature inside the flask is maintained at 130°C and the reaction is continued for about 1 hour, and when the epichlorohydrin is completely consumed, the flask is quickly cooled. When the temperature inside the flask drops to 50°C, add powdered sodium hydroxide little by little until the neutralization point is confirmed. As a result of gas chromatography analysis, the intermediate equivalent to 304g (yield 60%)

It was found that the following formula was obtained. After heating this intermediate as a crude product to around 100°C, a 20% by weight aqueous sodium hydroxide solution is added dropwise. While maintaining the pH of the reaction system at approximately 8,
250 g of the above sodium hydroxide aqueous solution was added in about 1 hour to complete the reaction (2). After the reaction product liquid is cooled to room temperature, it is separated into an aqueous phase and an oil phase using a separating funnel. The resulting oil phase is distilled and the intermediate

250g (yield 96%) of [Formula] was obtained. 46 g of flaked sodium hydroxide and 200 g of dehydrated industrial diglyme (diethylene glycol dimethyl ether) are charged into a 500 ml four-necked flask equipped with a McMahon column, and heated and stirred while the diglyme is refluxed. After obtaining a uniform dispersion, the intermediate is dropped into the flask. While keeping the top of the column below 130°C and the bottom of the column above 130°C, continue dropping the intermediate and a small amount of diglyme. In about 3 hours, 150g of the intermediate and 70g of diglyme are added dropwise. During this time
As the reaction (3) progresses, the produced GVE, diglyme, and a small amount of water are distilled out from the top of the column. When the distillate is cooled to room temperature and collected, it separates into two phases, and the crude GVE is separated from the aqueous phase using a separatory funnel. The obtained crude GVE was dehydrated with sodium sulfate, and then completely dehydrated with molecular sieves (4A).
Distillation under reduced pressure yields 34.4 g (third stage yield: 30%) of glycidyl vinyl ether (purity of 99.5% or higher). Example 2 (1) was carried out in the same manner as in Example 1, except that in the reaction (1) of Example 1, silica-alumina (28% by weight of 100 mesh alumina) equivalent to epichlorohydrin was used instead of concentrated sulfuric acid. The reaction was carried out. Approximately 1
After the reaction for several hours, immediately filter the reaction solution to remove the silica.
Alumina was removed. As a result of gas chromatography analysis, 329g of intermediate (yield 75%)
It was found that it was generated. Hereinafter, similar to Example 1
Perform reaction (2) and reaction (3), and finally purify
70 g of GVE (3rd stage yield 29%) was obtained. Comparative Example 1 Using 250 g of the intermediate obtained by carrying out the reactions (1) and (2) in the same manner as in Example 1, the reaction (3) was carried out without using diglyme. That is, in the reactor
When 250g of the intermediate and 46g of sodium hydroxide were charged and the reaction temperature was gradually raised, the reaction temperature reached 185℃ and a reaction accompanied by a sudden large exotherm occurred, and the inside of the reactor turned into a yellowish brown sponge-like polymer. Summer.
Only 5 g (4.5% yield) of GVE was produced. Comparative Example 2 The reaction (1) in Example 1 was carried out in the same manner as in Example 1, except that the reaction time was extended to 5 hours. As a result of gas chromatography analysis,
The yield of intermediate decreased to 200g (39% yield),
The proportion of high-boiling substances as by-products increased. Example 3 Reactions (1), (2), and (3) were carried out in the same manner as in Example 1, except that potassium hydroxide was used instead of sodium hydroxide in reaction (3). Summer. As a result, 23 g of purified GVE (yield 20%) was obtained.

Claims (1)

[Claims] 1. In producing glycidyl vinyl ether by the following three-step reactions (1) to (3) using ethylene chlorohydrin and epichlorohydrin as raw materials, the reaction (3) is performed by removing HCl. in a solvent that can at least partially dissolve the alkali as an agent at the reaction temperature and has a boiling point of 160-200°C, at 150-200°C.
1. A method for producing glycidyl vinyl ether, which is carried out by adding [Formula] little by little to a reaction system and distilling the product from the reaction system at a reaction temperature of . 2. The manufacturing method according to claim 1, wherein the alkali as the HCl removing agent is an alkali metal hydroxide. 3. The manufacturing method according to claim 1, wherein the solvent is an aprotic polar organic solvent. 4. The manufacturing method according to claim 3, wherein the solvent is a glycol ether. 5. The manufacturing method according to claim 4, wherein the solvent is diethylene glycol dimethyl ether. 6. The manufacturing method according to claim 1, wherein the reaction (1) is carried out in the presence of an acid catalyst. 7. The manufacturing method according to claim 6, wherein the acid catalyst is concentrated sulfuric acid. 8. The manufacturing method according to claim 1, wherein the reaction in (2) is carried out at a temperature selected from the range of 50°C or higher and lower than 150°C.