JPH10212294A - Production of acidic phosphoric ester mixture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mixture having an adjusted composition ratio by treating a mixture of a phosphoric monoester and a phosphoric diester with a metal oxide and water and adsorbing only the phosphoric monoester. SOLUTION: A metal oxide such as silicon oxide (silica gel) or alumina and water, preferably ion-exchanged water or distilled water are made to exist in a mixture of a phosphoric monoester and a phosphoric diester and the amount of water in the mixture is controlled to regulate the composition ratio of the phosphoric monoester and the phosphoric diester. The activity of a metal oxide is lowered when it contains water, a phosphoric monoester is specifically adsorbed on a metal oxide in the presence of water and a phosphoric diester is hardly adsorbed. Consequently the composition of the mixture can be simply adjusted and isolation and purification by a column chromatography, etc., is not required. The mixture is useful for an adhesive, a surfactant, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a mixture of acidic phosphate esters, more specifically, a mixture of acidic phosphate esters of monoester phosphate and diester phosphate, which is useful for applications such as adhesives and surfactants. About the method.

[0002]

2. Description of the Related Art Phosphoric acid monoesters, phosphoric acid diesters and mixtures thereof are used in various fields such as polymerization catalysts, surfactants, metal binding solvents, and antistatic agents for fibers. Further, among these, polymerizable acidic phosphate compounds having a polymerizable unsaturated group such as a (meth) acryloyl group in the molecule are characterized by good polymerizability, solubility of inorganic compounds, adhesion to metals, and the like. It is used in fiber treatment agents, paints, pretreatment agents for bonding, adhesives, dental materials and the like. In the present invention, phosphoric acid monoester and phosphoric acid diester each mean a simple substance, and an acidic phosphoric acid ester mixture means a mixture of both. In addition, the term “acidic phosphate compound” includes any of these simple substances and mixtures thereof.

[0003] In recent years, as high performance is required for the above-mentioned adhesives and the like, the necessity of a composition in which a monoester and a diester of phosphoric acid are mixed at a specific ratio has been increasing.

On the other hand, the above-mentioned acidic phosphate compound is generally synthesized by an esterification reaction between phosphoric acid or an active derivative thereof and an alcohol, so that the synthesized product is usually obtained as a mixture of mono-, di- and triesters. It is difficult to selectively synthesize phosphate monoesters or phosphate diesters and to synthesize these esters at any ratio.

Therefore, in order to obtain a composition having a phosphoric acid monoester and a phosphoric acid diester at an arbitrary ratio, a high-purity phosphoric acid monoester and a phosphoric acid diester alone are conventionally obtained by column chromatography or the like. Then, a complicated operation of mixing the components at a predetermined ratio was required.

[0006]

In view of the above, it is desired to develop a method for obtaining a mixture in which the ratio of phosphoric acid monoester and phosphoric acid diester is adjusted without requiring a complicated method such as column chromatography purification. Was rare.

[0007]

Means for Solving the Problems The present inventors have made intensive studies to solve the above-mentioned problems, and as a result, have found that a phosphate ester mixture,
In a system in which a metal oxide and water coexist, the adsorption capacity (activity) of a metal oxide to an organic compound decreases as the amount of water increases, that is, the activity decreases when the metal oxide contains water. Contrary to common wisdom, they found that phosphate monoesters were specifically adsorbed to metal oxides in the presence of water, whereas phosphate diesters were hardly adsorbed, and the composition of the mixture of phosphate monoester and phosphate diester was found. It has been found that the adjustment can be easily performed, and the present invention has been completed.

[0008] That is, the present invention provides a mixture of a phosphoric acid monoester and a phosphoric diester in which a metal oxide and water are present, and by controlling the amount of water in the mixture, the phosphoric acid monoester and the phosphoric acid diester. A method for producing an acidic phosphoric acid ester mixture, comprising controlling the composition ratio of a diester.

The acidic phosphoric ester mixture to which the production method of the present invention can be applied is not particularly limited in the structure of the phosphoric monoester and the phosphoric diester contained therein, and can be applied to known compounds.

Examples of such an acidic phosphate compound include a phosphate monoester having an aliphatic hydrocarbon group having 2 to 20 carbon atoms (the aliphatic hydrocarbon group may have a side chain). Phosphoric acid diester, phosphoric acid monoester and phosphoric acid diester having an aromatic hydrocarbon group having 2 to 20 carbon atoms (hereinafter, an aliphatic hydrocarbon group and an aromatic hydrocarbon group are collectively referred to as a hydrocarbon group), and Further, the hydrocarbon group may be substituted with an alkoxy group such as a methoxy group or an ethoxy group, a halogen group such as fluorine or chlorine, or a polymerizable unsaturated group such as a (meth) acryloyloxy group or a vinyl group. Good.

Specific examples of typical acidic phosphate compounds include mono- and diethyl phosphates, mono- and dipropyl phosphates, mono- and dibutyl phosphates, mono- and dihexyl phosphates, mono- and dioctyl phosphates, mono- and dioctyl phosphates. Dioleyl phosphate, mono and dilauryl phosphate, mono and dimyristyl phosphate, mono and distearyl phosphate, mono and diphenyl phosphate, mono and diisopropyl phosphate, mono and bis (2-ethylhexyl) phosphate, mono And bis (butoxyethyl) phosphate, mono and bis (lauryloxy) ethyl phosphate, mono and bis (2-chloropropyl) phosphate, mono and bis (2-acryloyl) Kishiechiru) phosphate, mono- and bis (3-acryloyloxy propyl) phosphate, mono- and bis (2-acryloyloxy propyl) phosphate, mono- and bis (6-acryloyloxy-hexyl) phosphate, mono- and bis (1
0-acryloyloxydecyl) phosphate, mono and bis (1-chloromethyl-2-acryloyloxyethyl) phosphate, mono and bis (2-methacryloyloxyethyl) phosphate, mono and bis (3-methacryloyloxypropyl) Phosphate, mono and bis (2-methacryloyloxypropyl) phosphate, mono and bis (6-methacryloyloxyhexyl) phosphate, mono and bis (1
0-methacryloyloxydecyl) phosphate, mono- and bis (1-chloromethyl-2-methacryloyloxyethyl) phosphate, 2-methacryloyloxyethylphenylphosphate and the like.

[0012] The method of the present invention can be applied to the above-mentioned acidic phosphoric acid ester mixture, in which the compound itself such as the acidic phosphoric acid ester mixture having a polymerizable unsaturated group is unstable and other production methods are difficult to apply. It is particularly suitable, and is most suitable for an acidic phosphate mixture having a (meth) acrylate structure which is easily decomposed as a polymerizable unsaturated group.

The method of the present invention is applicable even if the hydrocarbon group of the phosphoric acid monoester and the hydrocarbon group of the phosphoric diester in the acidic phosphoric acid ester mixture are different. As a specific example, a metal oxide and water act on a mixture of monophenyl phosphate and 2-methacryloyloxyethyl phenyl phosphate synthesized by reacting phenylphosphoric acid dichloride and 2-hydroxyethyl methacrylate. And adjusting the composition.

In the production method of the present invention, the factors controlling the change in the ratio between the phosphoric acid monoester and the phosphoric acid diester due to the adsorption of the phosphoric acid monoester include: And the shape of the metal oxide. However, at present, the quantitative relationship between these factors and the adsorption rate of the phosphate monoester is not clear, and must be determined empirically. However, the effect of the amount of water used on the adsorption rate is much greater than other effects, and this must be strictly controlled.

When the production method of the present invention is carried out, preliminary experiments are conducted on a small scale in advance to determine the amount of water used as the above-mentioned control factor, other action times, the amount of metal oxide used, its shape, and the like. A typical method is to apply the result to a large scale. Furthermore, it is also preferable to collect data by performing sampling or the like during the implementation stage on a large scale and to perform fine adjustment. In addition, by accumulating these data, it may be possible to omit a study on a small scale in advance under similar conditions.

The metal oxide used in the present invention includes:
Known ones are used without any particular limitation. Examples of such metal oxides include single or composite oxides of polyvalent metals such as silicon, aluminum, titanium, zirconium, nickel, cobalt, strontium, manganese, iron, copper, zinc, tin and magnesium. Add calcium, potassium,
Complex oxides containing metals which are extremely unstable when converted into a single oxide such as sodium are also included.

Specifically, silicon oxide (hereinafter, referred to as silica gel), aluminum oxide (hereinafter, referred to as alumina), titanium oxide, zirconium oxide, nickel oxide,
Single metal oxides such as cobalt oxide, strontium oxide, manganese oxide, iron oxide, copper oxide, zinc oxide, tin oxide, magnesium oxide, and silicon-titanium composite oxide,
Silicon-zirconium composite oxide, silicon-aluminum composite oxide, silicon-calcium composite oxide, silicon-nickel composite oxide, silicon-cobalt composite oxide,
Silicon-strontium composite oxide, silicon-manganese composite oxide, silicon-iron composite oxide, silicon-copper composite oxide, silicon-zinc composite oxide, silicon-tin composite oxide, silicon-magnesium composite oxide, aluminum −
Titanium composite oxide, aluminum-zirconium composite oxide, aluminum-sodium composite oxide, zirconium-yttrium composite oxide, cobalt-nickel composite oxide, aluminum-zinc-cobalt composite oxide,
Silicon-aluminum-calcium composite oxide, silicon-aluminum-magnesium composite oxide, silicon-aluminum-iron composite oxide, silicon-titanium-sodium composite oxide, silicon-zirconium-sodium composite oxide, silicon-aluminum-titanium -Magnesium composite oxide, silicon-aluminum-titanium-sodium composite oxide, silicon-aluminum-titanium-potassium composite oxide, silicon-aluminum-zirconium-
Composite metal oxides such as calcium composite oxides are included.

Of these, the use of metal oxides which are stable against water, particularly acidic water, is preferred. Further, silica gel and alumina are practically non-toxic and can be easily and inexpensively prepared in various shapes. It is preferably used because it is available, and silica gel is most preferably used.

The amount of the metal oxide used in the present invention with respect to the acid phosphate mixture is not particularly limited, and the composition ratio of the acid phosphate mixture before the composition adjustment at that time and the intended composition ratio, etc. However, if the amount is too small, the phosphoric acid monoester may not be sufficiently adsorbed, and the desired composition ratio may not be reached. Therefore, it is preferable to use 5 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the acidic phosphoric acid ester mixture.
It is more preferred to use from 300 to 300 parts by weight.

The shape of the metal oxide used in the present invention is not particularly limited, and may be appropriately selected according to the conditions at each time. For example, metal oxides with a small particle size (large specific surface area) have a high phosphate monoester adsorption rate and a large final adsorption amount, so the amount used to achieve the desired composition ratio is small. In addition, there is a feature that the composition ratio can be adjusted in a short time, while a metal oxide having a large particle size is easy to handle. In consideration of operability and practically possible action time, use of a metal oxide having an average particle size of 0.005 mm to 10 mm is preferable, and use of a metal oxide having a mean particle size of 0.01 mm to 5 mm is more preferable.

In the present invention, water is necessary for adsorbing the phosphate monoester to the metal oxide. In the absence of water, the adsorption of the phosphoric acid monoester does not occur, so that the composition ratio cannot be adjusted.

The water used in the present invention is not particularly limited, but preferably contains no impurities in order to suppress the occurrence of side reactions and the like, and ion-exchanged water and distilled water are preferably used. .

The amount of the water to be used in the present invention with respect to the acidic phosphoric acid ester mixture is not particularly limited, and may be appropriately selected according to the conditions at each time. Specifically, the larger the amount of water used, the more the adsorption of the phosphate monoester proceeds, and when other conditions such as the action time and the shape of the metal oxide are the same, the presence of the phosphate monoester is increased. A low ratio can be obtained. On the other hand, when the amount used is small, the adsorption speed is low, so that fine composition adjustment is possible. In order to adjust the composition ratio within a practically acceptable action time, the amount of water used is preferably 1 part by weight to 50 parts by weight, and more preferably 3 parts by weight based on 100 parts by weight of the acidic phosphate mixture. Parts to 30 parts by weight are more preferred.

The action time of the metal oxide and water in the present invention is not particularly limited. In general, the longer the action, the more the adsorption of the phosphate monoester proceeds, and finally the longer the action of the phosphate monoester. An ester having a low abundance ratio is obtained. However, too long an action is not practical since the adsorption rate of the phosphate monoester gradually decreases. Conversely, since the adsorption rate is high immediately after the start of the action, an extremely short action time may cause a large difference in the ratio of the phosphate monoester obtained with a slight difference in the action time. Effectively effective action times are from 5 minutes to 48 hours,
An action time of 15 minutes to 24 hours is preferred.

In the method of the present invention, the acidic phosphoric ester mixture is usually a viscous liquid. Therefore, in order to improve the operability, it is necessary to form a solution with an organic solvent, and to allow a metal oxide and water to act on the solution. preferable.

It is preferable to use such an organic solvent which does not have a hydroxyl group or a carboxyl group in order to avoid an undesired reaction with the phosphoric acid ester mixture. It is preferable to use a material that is stable to the material.

Specific examples of such organic solvents include halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride, dichloroethane and trichloroethane, and ethyl ether, propyl ether, tetrahydrofuran and 1,2-dimethoxyethane. Examples include ethers, aromatic hydrocarbons such as toluene and xylene. In the selection of these organic solvents, when the target acidic phosphate mixture is a compound having a (meth) acrylate structure which is unstable to heat, light, etc.,
After the adjustment of the composition ratio, it is preferable to use one having a boiling point at normal pressure of 100 ° C. or lower, more preferably 70 ° C. or lower, in order to facilitate the removal of the solvent. In consideration of these, dichloromethane, chloroform and ethyl ether are preferably used, and in view of flammability and biosafety, use of dichloromethane is most preferable.

In the method of the present invention, the method of action of the acidic phosphoric ester mixture, water and metal oxide is not particularly limited, and all three components exist in the same reaction vessel for a predetermined time. It may be determined appropriately according to the conditions at each time. As an example, a predetermined amount of a metal oxide is put in a reaction vessel, and after a solution in which an acidic phosphate mixture is dissolved is put therein,
A method in which a predetermined amount of water is added, a method in which a predetermined amount of water is added to a solution of the acid phosphate mixture, and a method in which the water is added to a reaction vessel in which a metal oxide is previously placed, or a method in which the acid phosphate mixture is added. In a reaction vessel, and then a predetermined amount of water and a metal oxide are charged therein.

In the method of the present invention, the adsorption of the phosphate monoester is carried out by mixing an acidic phosphate ester mixture,
Since the action must take place when all of the water and the metal oxide are present, the working time in the present invention is the time after being charged into the same reaction vessel. For example, even if the acid phosphate mixture and the metal oxide are mixed, the mixture is stable as it is, and adsorption is started only when water is added thereto. The operation may be performed as time.

In the method of the present invention, when water and a metal oxide are allowed to act on the acidic phosphoric ester mixture, stirring is preferably performed. Without stirring, the system will be in an inhomogeneous state, which may cause a difference between the results of the preliminary experiment on the small scale and the results on the large scale, and may cause errors when data is obtained by sampling during the process. There is. The stirring is most preferably performed throughout the working time, but if it is difficult to do so due to any restrictions, stirring may be performed at regular intervals, for example, stirring for 10 minutes every hour for 5 hours. A method is also possible.

In the method of the present invention, when a predetermined operation time has elapsed and a desired composition ratio has been obtained, the metal oxide is removed from the system, and the change in the composition ratio due to further adsorption is stopped. The method for removing the metal oxide is not particularly limited, and a known method can be used. In particular,
Examples include filtration, centrifugation, and decantation.

In the operation of removing the metal oxide, the operation may require a long time. Therefore, when examining the conditions such as the amount of the metal oxide and water used and the operation time, the point is taken into consideration. It is preferable to determine. For example, if it is assumed that the removal operation takes one hour, even if there is a difference of about ± 1 hour with respect to the predetermined action time, the composition ratio of the obtained acidic phosphate mixture may be different from the target value by more than the error range. There are no conditions.

In the method of the present invention, water is allowed to act on the acidic phosphate ester mixture together with the metal oxide. However, the final form of the acidic phosphate ester mixture preferably contains as little water as possible. Often preferred.
Usually, most of the water is adsorbed on the metal oxide and is removed together with the metal oxide. However, when the amount of water used is considerably large or when the water content required as a product is extremely small, an operation for further removing water is required. As a method for removing water in such a case, a known method can be used without limitation as long as it does not affect the composition ratio of the acidic phosphate mixture. Examples of such a method include a method using a non-oxide desiccant such as calcium sulfate, such as sodium sulfate and magnesium sulfate, and an organic solvent azeotropic with water, for example, toluene, ethyl acetate, chloroform, or the like. Removal method. In the method of the present invention, when the operation is performed using any of the above-mentioned organic solvents, a solution of an acidic phosphate mixture is obtained. For subsequent use of the resulting acid phosphate mixture, it is necessary to remove the solvent if it is not needed. As such a solvent removing method, a known method can be used without any limitation. Specific examples include heating at a pressure equal to or higher than the boiling point of the solvent at normal pressure, heating under reduced pressure, or removing the solvent by blowing air, nitrogen, or the like into the solution. On the other hand, after adjusting the composition ratio, when using the acidic phosphoric acid ester mixture as any solution, a solvent that dissolves the acidic phosphoric acid ester mixture when the metal oxide and water are allowed to act, and finally used If it is possible to use the same solvent as the solvent, it is preferable to do so. This saves the trouble of removing the solvent.

In the present invention, a metal oxide and water are allowed to act on the acidic phosphoric ester mixture, whereby
It is not clear why only the phosphate monoester is specifically adsorbed, but since adsorption does not occur in the absence of water, firstly, the water and the surface of the metal oxide cause some reaction, and this reaction surface It is thought that it may interact with two phosphate acidic hydroxyl groups of the phosphate monoester.

[0035]

According to the production method of the present invention, a monophosphate and a diester of phosphoric acid are reduced from an acidic phosphoric ester mixture composed of a monoester of phosphoric acid and a diester of phosphoric acid by reducing the abundance of the monoester of phosphoric acid. By controlling the composition ratio, an acidic phosphate mixture having an arbitrary composition can be easily obtained.

[0036]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

In the following examples, the composition ratio of the acidic phosphoric ester mixture (and other components, if any) is the ratio of the integrated values of the peaks by high performance liquid chromatography analysis (column used). : Inertsil OD
S-2, manufactured by Gaschrom Industry, detection: UV 210n
m).

The acidic phosphoric acid ester mixture used in Examples 1 to 9 and Comparative Examples 1 to 3 was obtained by purifying light ester PM (manufactured by Kyoeisha Chemical Co., Ltd.), which is a commercially available acidic phosphoric acid ester mixture, by column chromatography. Mono (2-methacryloyloxyethyl) phosphate (hereinafter, PM) which is an acid monoester and bis (2-methacryloyloxyethyl) phosphate (hereinafter, PM2) which is a phosphoric diester were isolated, and the respective examples and comparisons were made. It is a mixture for each example. As the acid phosphate ester mixture used in 10 in the practical examples, light ester PM was used as it was. The acid phosphate mixture used in Example 11 is a commercially available acid phosphate mixture, Phosmer CL.
(Manufactured by Unichemical Co., Ltd.) was purified by column chromatography, and mono (1-chloromethyl-2-methacryloyloxyethyl) phosphate (hereinafter referred to as PM-CL), which is a phosphate monoester, and bis, which was a phosphate diester, were used. (1-Chloromethyl-2-methacryloyloxyethyl) phosphate (hereinafter PM2-CL) is isolated and mixed.

Example 1 A 300 ml Pyrex glass Erlenmeyer flask was charged with P
19.0 g of a mixture of M and PM2 having a composition ratio of 41: 100
Was added and dissolved by adding 131 g of dichloromethane to obtain a solution. 3.0 g of ion-exchanged water and 30 g of silica gel (manufactured by Wako Pure Chemical Industries, silica gel, small particles, white) were added to this solution, and the mixture was stirred with a magnetic stirrer. After 1 hour, the silica gel was filtered off using filter paper (5B). The solvent was removed from the obtained solution using a rotary evaporator, and 18.0 g of a mixture of acidic phosphates was recovered. The recovered PM and PM2 have a composition ratio of 34:
It was 100.

Example 2 The procedure was as in Example 1, except that the amount of ion exchanged water used was 4.5 g. The amount of the recovered acidic phosphate mixture was 17.5 g, and the ratio of PM: PM2 was 30: 1.
00.

Example 3 The procedure was as in Example 1, except that the working time was 3 hours. The amount of the acid phosphate mixture recovered is 1
7.2 g, PM: PM2 was 27: 100.

Example 4 The procedure of Example 2 was repeated except that the working time was 3 hours. The amount of the acid phosphate mixture recovered is 1
6.3 g, PM: PM2 was 21: 100.

Example 5 The procedure of Example 1 was repeated except that the amount of ion-exchanged water used was 1.5 g, the amount of silica gel used was 45 g, and the operation time was 3 hours. The amount of the recovered acidic phosphate mixture was 18.4 g, and the ratio of PM: PM2 was 37: 100.

Comparative Example 1 The procedure of Example 1 was repeated except that no ion-exchanged water was added. The amount of the acid phosphate mixture recovered is 1
8.9 g, PM: PM2 remained at 41: 100.

Comparative Example 2 The procedure of Example 3 was repeated except that no ion-exchanged water was added. The amount of the acid phosphate mixture recovered is 1
8.9 g, PM: PM2 remained at 41: 100.

[0046]

[Table 1]

Table 1 summarizes the results of Examples 1 to 5 and Comparative Examples 1 and 2. As is clear from the results of the comparison between Examples 1 and 2 and Comparative Example 1 and the comparison between Examples 3 and 4 and Comparative Example 2, adsorption of the phosphate monoester occurred only in the presence of water. From the results of Examples 1 to 4, it is clear that the composition ratio of the obtained acidic phosphate mixture can be controlled by controlling the amount of water used and the duration of action. Further, in Example 5 in which the amount of water used was half that of Example 1, the amount of PM adsorbed was small despite the fact that 1.5 times the amount of silica gel was used and the action time was tripled. It can be seen that water usage is the most dominant factor.

Example 6 According to Example 1, the composition ratio of PM: PM2 was 57:10.
A solution prepared by dissolving 48 g of the mixture of 0 in 260 g of dichloromethane was prepared. 6.0 g of ion-exchanged water and silica gel (manufactured by Wako Pure Chemical Industries, small silica gel particles) in this solution
60 g was added and the mixture was stirred with a magnetic sooter. Sampling was performed at each time shown in Table 2 to check the composition ratio. The results are shown in Table 2.

Example 7 According to the method of Example 1, the composition ratio of PM: PM2 was 5
A solution prepared by dissolving 46 g of a 1: 100 mixture in 260 g of dichloromethane was prepared. Add ion-exchanged water to this solution 2.
1 g and 60 g of silica gel (Wako Pure Chemical Industries, silica gel small white) were added and stirred with a magnetic stirrer. Sampling was performed at each time shown in Table 2 to check the composition ratio. The results are shown in Table 2.

[0050]

[Table 2]

Examples 6 and 7 show changes in the composition ratio with respect to the action time of the metal oxide and water. As is clear from the results, the composition ratio changes with the passage of time, and the composition ratio of the obtained acidic phosphate mixture can be controlled by controlling the operation time. In addition, a comparison between Examples 6 and 7 shows that the adsorption rate can be reduced by reducing the amount of water to act, and fine composition adjustment becomes possible.

Example 8 According to the method of Example 1, the composition ratio of PM: PM2 was 5
A solution prepared by dissolving 48 g of the 7: 100 mixture in 260 g of dichloromethane was prepared. Add ion-exchanged water to this solution.
Then, 0 g and 60 g of silica gel (manufactured by Wako Pure Chemical Industries, silica gel medium grain white) were added, and the mixture was stirred for 2 hours. The composition ratio of the obtained acidic phosphate mixture was 54: 100.

Example 9 Wakogel C-200 (manufactured by Wako Pure Chemical Industries) as a metal oxide
Example 8 was carried out except that was used. The composition ratio of the obtained acidic phosphate mixture was 38: 100.

Comparative Example 3 The same procedure as in Example 8 was carried out except that sodium sulfate (manufactured by Wako Pure Chemical Industries, special grade of reagent) was used instead of the metal oxide. The composition ratio of the obtained acidic phosphate mixture is 57: 100.
It was still.

In Examples 8 and 9 and Example 6 where the action time was 2 hours, the difference in the shape of the silica gel used was observed. In each case, it can be seen that the abundance ratio of the phosphoric acid monoester decreases and the composition changes.
Further, it can be seen that the smaller the particle size of the silica gel used, the larger the adsorption amount of the phosphoric acid monoester. Comparative Example 3
Is the result when sodium sulfate, which is not a metal oxide but has water adsorption ability like silica gel, is used. In this case, the adsorption of the phosphoric acid monoester does not occur, and the composition cannot be adjusted.

Example 10 30 g of a mixture having a composition ratio of PM: PM2 of 186: 100 and further containing ethylene glycol dimethacrylate (hereinafter referred to as 1G) as an impurity (PM: PM2: 1G = 1
86: 100: 105, integral ratio) in dichloromethane 1
A solution dissolved in 70 g was prepared. 2.0 g of ion-exchanged water and alumina (Alumina A manufactured by Showa Denko
-12 (average particle size: 60 μm) and stirred for 2 hours. The composition ratio of the obtained acidic phosphate mixture was 9
4: 100 (PM: PM2: 1G = 94: 100: 10
5).

Example 11 20 g of a mixture of PM-CL and PM2-CL having a composition ratio of 150: 100 was dissolved in 80 g of dichloromethane. 3.5 g of ion-exchanged water and 25 g of silica gel (manufactured by Wako Pure Chemical Industries, silica gel, small particles, white) were added to this solution, and the mixture was stirred for 4 hours. The composition ratio of the obtained acidic phosphate mixture was 105: 100.

Example 10 shows the results when the metal oxide was changed from silica gel to alumina, and Example 11 shows the results when the type of the acidic phosphate mixture for adjusting the composition was changed. In each case, the composition ratio between the phosphoric acid monoester and the phosphoric acid diester changed, indicating that the composition ratio, which is the object of the present invention, can be adjusted.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Noritoshi Yamaguchi 1-1-1, Mikage-cho, Tokuyama-shi, Yamaguchi Pref.

Claims (1)

[Claims] 1. A composition ratio of a phosphoric acid monoester and a phosphoric diester by allowing a metal oxide and water to be present in a mixture of a phosphoric acid monoester and a phosphoric acid diester, and controlling the amount of water in the mixture. A method for producing an acidic phosphoric acid ester mixture, characterized in that: