JPH107807A - Cleaning of phosphoric ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a purified phosphoric ester in high yield without discharging cloudy wastewater at all by adding a necessary component to the wastewater produced by rinsing and reusing the resultant wastewater as wash water. SOLUTION: A cleaning step for extracting and separating a metal in the aqueous phase with wash water without forming an emulsion with a phosphoric ester and a rinsing step for rinsing the metal and chlorine components contained in water remaining together with the phosphoric ester phase are carried out when reacting phosphorus oxychloride with a dihydric phenol and a monohydric phenol in the presence of a metallic chloride catalyst and then removing the catalyst metal and chlorine components from the resultant aryl phosphate oligomer. Wastewater produced in the rinsing step is reused as wash water. Acidic water at pH<=2.6 or wash water containing a hydrogenphosphate soluble in water at <=0.3mol/L concentration or alkaline water at pH>=12.5 is preferred as the wash water. Thereby, the metallic component derived from the catalyst can be removed without deteriorating the yield of the product.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a phosphoric acid ester which has excellent heat resistance and is useful as an additive for resins. More specifically, the present invention relates to a cleaning method for removing a catalytic metal from an oligomer type phosphoric ester obtained by reacting phosphorus oxychloride with a dihydric phenol and a monohydric phenol in the presence of a metal chloride catalyst.

[0002]

2. Description of the Related Art Phosphate esters are widely used as additives for resins because they exhibit excellent properties such as flame retardant effect, plasticity effect and antioxidant effect when mixed with resin. Among them, the oligomer type aryl phosphate represented by the following general formula [1] is excellent in heat resistance, and hardly causes problems such as volatilization during molding, bleeding to the resin surface (bleeding), and mold contamination. In addition, since a resin composition having well-balanced physical properties can be obtained, it has attracted attention as a flame retardant such as a thermoplastic resin, particularly a polystyrene resin, a polycarbonate resin, a polyphenylene ether resin, or a polyester resin.

[0003]

Embedded image

(Wherein n is an integer of 0 to 10;
Ar2, Ar3, and Ar4 are the same or different monovalent aromatic groups, and R is a divalent aromatic group. For example, Japanese Patent Publication No. 51-19858 and Japanese Patent Publication No.
Japanese Patent No. 39271 discloses a polyester-based flame-retardant resin composition containing these additives.
No. 7, JP-A-4-279660 and the like, a polyphenylene ether-based resin composition,
Japanese Patent No. 6 and US Pat. No. 5,061,745 describe polycarbonate resin compositions.

[0005] The aryl phosphates of the general formula [1] are usually prepared in US Pat.
No. 25706, JP-A-63-227632,
EP 0 613 902 A1 and the like,
It is synthesized by a method of reacting phosphorus oxychloride with dihydric phenol and monohydric phenol in the presence of a Lewis acid catalyst. As the Lewis acid catalyst, metal chlorides such as anhydrous magnesium chloride, aluminum chloride, titanium chloride, and iron chloride are preferably used.

However, these metals act as catalysts for transesterification and hydrolysis at high temperatures, and if they remain in the phosphoric ester, they may be extruded during extrusion molding with a resin.
It causes gelation and decomposition of not only phosphate ester but also resin itself, significantly lowering the physical properties of the resin composition, contaminating the mold, reducing productivity, and causing mold corrosion. It has been known. Therefore, the operation of removing the catalytic metal component from the synthesized phosphate ester is extremely important in the entire production process.

[0007] Since the aryl phosphate ester has a high boiling point and cannot be purified by distillation, a washing and purifying method of extracting a metal component into an aqueous phase with hot water, acidic water or alkaline water is mainly used. However, washing with hot water cannot sufficiently remove metal components, and at the same time, tends to cause emulsification, making it difficult to separate the aqueous phase and the phosphate phase.

On the other hand, acidic washing water having a specific pH or less, alkaline washing water having a specific pH or more, washing water having a pH buffering action near neutrality, hydrogen phosphate having a specific concentration or more, and the like. It is known that emulsification of a phosphate ester can be prevented by using washing water containing a valent electrolyte. However, acids and alkalis contained in these washing waters,
Other components promote the transesterification reaction and hydrolysis at a high temperature in the same manner as the catalytic metal component. Therefore, after washing with these components, it is necessary to rinse and remove the washing liquid components with clear water. However, when the pH of the rinsing water deviates from the specified range or the concentration of the electrolyte or the like falls below the specified range, a part of the phosphate ester is emulsified and the wastewater becomes cloudy, which makes it difficult to recover the product. There is a problem that the yield is reduced and the load of wastewater treatment is increased.

[0009]

DISCLOSURE OF THE INVENTION The present invention provides a method for removing a metal component derived from a catalyst from an aryl phosphate represented by the formula [1] by a simple method without reducing the yield of the product, and It is an object of the present invention to provide a method for washing and removing a catalyst, in which a small amount of phosphates and phosphates are not mixed into wastewater, turbid wastewater is not produced, and the load on wastewater treatment is small.

[0010]

Means for Solving the Problems The present inventors have studied diligently to achieve the above-mentioned object, and as a result, added necessary components to waste water generated by rinsing, and re-used as washing water. By using, without giving out turbid wastewater at all,
It has been found that a purified phosphate ester can be obtained in high yield, and the present invention has been completed.

That is, the present invention is as follows. 1. Forming an emulsion with a phosphoric ester to remove the catalytic metal and chlorine from an aryl phosphate ester oligomer obtained by reacting phosphorus oxychloride with dihydric phenol and monohydric phenol in the presence of a metal chloride catalyst The metal is extracted into the aqueous phase by washing water without
In the washing and purifying step comprising a washing step for separating and a rinsing step for rinsing metal and chlorine contained in water remaining together with the phosphate ester phase, wastewater generated in the rinsing step is reused as washing water. Method for washing phosphate ester. 2. The above 1 wherein the washing water is acidic water having a pH of 2.6 or less.
Method for washing phosphate ester. 3. When the washing water has a concentration of 0.3 mol / liter or more,
The washing method of the above-mentioned phosphate ester containing a water-soluble hydrogen phosphate. 4. The washing method of the above-mentioned 1 wherein the washing water is alkaline water having a pH of 12.5 or more.

Hereinafter, the present invention will be described in detail. Examples of the metal chloride catalyst used in the synthesis include anhydrous magnesium chloride, aluminum chloride, titanium chloride, tin chloride,
Zinc chloride, iron chloride and the like can be mentioned, and these can be used alone or in combination. In particular, anhydrous magnesium chloride and aluminum chloride are preferably used alone or in combination.

As the dihydric phenol used in the synthesis, for example, hydroquinone, resorcinol, catechol, biphenyl-3,3'diol, biphenyl-4,4'diol, bisphenol A, bisphenol S, bisphenol F, etc., alone or in combination Can be used. Among them, any one of hydroquinone, resorcinol, and bisphenol A alone is suitably used in terms of reactivity and product performance. Among them, a phosphoric ester obtained by using bisphenol A is excellent in hydrolysis resistance and is particularly preferable.

The monohydric phenol used for the synthesis includes, for example, phenol, cresol, xylenol, trimethylphenol, isopropylphenol, di-t-phenol.
Alkyl phenols such as butylphenol and nonylphenol, phenylphenol, benzylphenol, cumylphenol, naphthol and the like can be used alone or in combination. Among them, those using phenol, cresol and xylenol alone or in combination are preferable because they are easy to synthesize and exhibit excellent flame retardancy.

As the method for synthesizing the aryl phosphate ester oligomer, known methods described in the above-mentioned publications can be used, but phosphorus oxychloride is reacted with dihydric phenol in the presence of a metal chloride catalyst. After that, unreacted phosphorus oxychloride is removed, and a monohydric phenol is further added to complete the reaction, and the method described in JP-A-63-227632 is preferable because triaryl phosphate is less produced as a by-product.

The ease with which the phosphate ester is emulsified in the washing step depends on the type and composition of the phosphate ester. However, as the washing water, acidic washing water having a pH of 3 or less, which is adjusted by using waste water generated in the rinsing step, or pH 1 or less.
2 or more alkaline washing water, pH in the range of pH 4-10
Wash water having a buffering action, wash water containing a hydrogen phosphate soluble in water at a concentration of 0.1 mol / l or more, and wash water containing a polyvalent electrolyte at a concentration of 0.1 mol / l or more are used. Thus, emulsification can be prevented and the wastewater does not become cloudy.

The type of acid used for the acidic washing water is not particularly limited, but hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, boric acid, oxalic acid and acetic acid are easy to use, and hydrochloric acid, sulfuric acid and oxalic acid are particularly preferred.
The concentration of the acid may be pH 3 or less.
6 or less is preferable because the catalytic metal removal effect is high.
The range of H0 to 2 is more preferred. This range is approximately 0.01 to 2N in terms of acid concentration.

The kind of alkali used for the alkaline washing water is not particularly limited, but sodium hydroxide, potassium hydroxide, aqueous ammonia and the like are easy to use, and sodium hydroxide is particularly preferred. The concentration of the alkali may be pH 12 or higher, but pH 12.5 or higher is preferable because the catalytic metal removal effect is high, and pH 13 to 14 is particularly preferable. This range is approximately 0.03 to 2N in terms of alkali concentration.

Examples of the water-soluble hydrogen phosphate include, for example, disodium hydrogen phosphate, sodium dihydrogen phosphate, dipotassium hydrogen phosphate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, sodium ammonium hydrogen phosphate and the like. Can be used alone or as a mixture. Also, phosphoric acid and sodium hydroxide, potassium hydroxide,
An alkali such as ammonia water may be mixed and used so as to have a predetermined composition. When a cleaning solution containing these is used,
The catalytic metal precipitates in the aqueous phase as a precipitate of hydrogen phosphate. In order to prevent the phosphate ester from being suspended in the wastewater, the concentration of the hydrogen phosphate may be 0.1 mol / liter or more. Is preferably 0.3 mol / liter or more,
0.5 mol / liter or more is more preferable. Although there is no particular upper limit of the concentration, the effect is not changed even if the concentration is too high, and the amount of discharged phosphorus increases and the load of wastewater treatment increases.

As a solution having a pH buffering action in the range of pH 4 to 10, in addition to a buffer containing a hydrogen phosphate, for example, S
φrensen's buffer, Gomori's buffer, HE
PES buffer and the like. Examples of polyvalent electrolytes include anions such as boric acid and citric acid and cations such as magnesium, zinc, iron and manganese, in addition to phosphate (hydrogen) ions.

Although the rinsing method is not particularly limited, it is preferable to repeat the operation so as to remove as much as possible the catalyst, the metal components and the chlorine components derived from the raw materials, and the components derived from the washing water.
On the other hand, when the number of repetitions of the rinsing operation is increased, the suspension of the phosphate in the aqueous phase becomes remarkable, and the separation speed is reduced and the interface becomes unstable, so that it is difficult to separate the aqueous phase and the phosphate phase. Becomes For this reason, the number of times of rinsing is suitably 1 to 10 times, more preferably 2 to 5 times.
The rinsing conditions are selected so that the concentrations of the components for precipitating the metal components, the alkali components, and the like are each approximately 10 ppm or less.

A feature of the washing method of the present invention is that the above-mentioned necessary components for washing water are added to the waste water generated in the rinsing step and used in the washing step, whereby the water is suspended in the aqueous phase in the rinsing step. The phosphate aggregates again and there is no suspension of the phosphate in the wastewater. In addition, since the distribution of phenols and hydrophilic esters to the phosphate ester phase and water is in equilibrium, the concentration of phenols and hydrophilic esters is
This is substantially the same as drainage when a cleaning liquid obtained by adding necessary components to pure water is used. As a result, the amount of wastewater generated in the rinsing step is reduced, so that products can be obtained at a high yield and the load of wastewater treatment is reduced.

When the rinsing operation is repeated several times, for example, when the rinsing operation is repeated twice, the rinsing waste liquid discharged is stored in a tank or the like using clear rinsing water for the second and final rinsing operation. Then, it is used for the first rinsing at the next production, and the waste liquid is added with components necessary for cleaning such as acid components, and then rinsed as used in the next cleaning process at the next production. Reuse the drainage like a counter flow,
Finally, a component for preventing emulsification, such as acid, is added and used in the washing step, so that the total amount of the discharged phenol component and hydrophilic phosphate ester can be reduced to one washing step regardless of the number of times of rinsing. Can be reduced.

The clear rinsing water used in the final round of the rinsing operation is not particularly limited as long as it is in the category of so-called tap water having a content of alkali and alkaline earth metal of about 100 ppm or less. So-called pure water, such as ion-exchanged water or distilled water, containing substantially no metal component is preferred. The ratio of the phosphate to the washing or rinsing water is not particularly limited as long as sufficient contact between the phosphate and the washing or rinsing water can be ensured. It is preferable to use twice the washing liquid or rinsing water, more preferably 0.2 to 5 times.

As a device used for washing and rinsing, a general mixer / settler type washing device is preferably used.
For mixing the phosphoric acid ester as the reaction product with the washing water or the rinsing water, for example, a stirring and mixing tank or a line mixer can be used. According to the method of the present invention, since the liquid-liquid separation rate of the phosphate ester and the washing water or the rinsing water is usually sufficiently high, the separation method of the ester phase and the aqueous phase after washing and rinsing is performed by a general gravity method using a settler or the like. It is possible to separate them by a separation method. Alternatively, an alternating current continuous liquid-liquid extraction device may be used.

The aryl phosphate ester obtained by removing the catalytic metal component by the method of the present invention and then removing water and the like by distillation or the like has excellent heat resistance and can be suitably used as a resin additive such as a flame retardant.

[0027]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described specifically with reference to examples. First, the analysis method used in the present invention will be described below. Composition of phosphate ester (A) Tosoh GPC column Tosoh TSKgel G2000HXL 2 Tosoh TSKgel G3000HXL 1 in series Solvent THF flow = 1ml / min Detector UV λ = 254nm Sample THF 1000 times dilution 50μl Absolute calibration line method A Column Tosoh TSKgel ODS-80T Solvent Methanol / water = 90/10 flow = 0.5 ml / min Detector UV λ = 254 nm Sample Methanol 50-fold dilution 10 μl Absolute calibration curve method Determination of phosphate and metal in wastewater ICP method equipment Seiko JY-38PII type sample MIBK 30-fold dilution absolute calibration curve method The structural formulas and compositions of the phosphate esters used in the examples and comparative examples are shown in Tables 1 and 2. The respective synthesis methods are shown below.

Synthesis of [Phosphate 1] 9.10 kg of bisphenol A dehydrated by heating and drying
(40 mol), 15.35 kg (100 mol) of phosphorus oxychloride, and 58 g (0.6 mol) of anhydrous magnesium chloride
With a stirrer, reflux tube and vacuum distillation equipment.
Prepared in a 0 liter GL reactor, under nitrogen flow
The reaction was performed at 0 ° C. for 6 hours. After completion of the reaction, the pressure in the reactor was reduced to 50 mmHg while maintaining the reaction temperature, and unreacted phosphorus oxychloride was recovered. Then, the reactor was cooled to 70 ° C, 15.05 kg (160 mol) of phenol was added, and the mixture was heated to 100 to 150 ° C and reacted for 7 hours. The pressure was gradually reduced to 10 mmHg at the same temperature to remove a part of the unreacted phenol to obtain 26.8 kg of a reaction product.

Synthesis of [Phosphate 2] 456.4 g (2.0 mol) of bisphenol A, 1226.8 g (8.0 mol) of phosphorus oxychloride, and 2.8 g (0.015 mol) of anhydrous magnesium chloride were stirred. Into a 2000ml four-necked flask equipped with
The reaction was carried out at 70 to 120 ° C. for 5 hours under a nitrogen stream. After completion of the reaction, the flask was evacuated to 50 mmHg with a vacuum pump while maintaining the reaction temperature, and unreacted phosphorus oxychloride was collected with a trap. Then cool the flask to room temperature,
488.5 g (4.0 mol) of 2,6-xylenol and 2.0 g (0.015 mol) of anhydrous aluminum chloride were added, and the mixture was heated to 100 to 150 ° C. and reacted for 5 hours. The flask was then cooled to room temperature and phenol 376.0
g (4.0 mol) was added, and the mixture was heated to 100 to 150 ° C. and reacted for 5 hours. The pressure was gradually reduced to 10 mmHg at the same temperature, and some unreacted phenol was distilled off to remove
02 g of reaction product were obtained.

Synthesis of [Phosphate 3] 220.8 g (2.0 mol) of resorcinol, 768.3 g (5.0 mol) of phosphorus oxychloride, and 2.8 g (0.015 mol) of anhydrous magnesium chloride were discharged. Charged into a 2000 ml four-necked flask equipped with a stirrer and a reflux tube connected to a pressure reducing facility via a tube and a trap, and placed under a nitrogen stream.
The reaction was performed at 0 to 120 ° C for 5 hours. After the completion of the reaction, the flask was evacuated to 50 mmHg while maintaining the reaction temperature, and unreacted phosphorus oxychloride was collected by a trap. The flask was then cooled to room temperature and 752.1 g of phenol (8.
0 mol), and the mixture was heated to 100 to 150 ° C. and reacted for 5 hours. The pressure was gradually reduced to 10 mmHg at the same temperature, a part of unreacted phenol was distilled off, and 1058 g
The reaction product of was obtained.

[0031]

Comparative Example 1 500 g of [Phosphate 1] and 0.05 N hydrochloric acid 50 as a washing solution were placed in a 2-liter separable flask equipped with a baffle, a stirrer and a coating heater.
After 0 g was charged and mixed and stirred at 80 ° C. for 30 minutes, the stirring was stopped, and the mixture was allowed to stand at the same temperature for 30 minutes to separate, and the aqueous phase was extracted (washing).

Add 500 g of distilled water to the phosphate ester,
After mixing and stirring at 80 ° C. for 30 minutes, the stirring was stopped, the mixture was allowed to stand still at the same temperature for 30 minutes, and the aqueous phase was extracted (rinse 1). The same operation was further repeated (rinse 2). Table 3 shows the analysis values of the phosphates after each drainage and rinsing.

[0033]

Example 1 In a 300 ml separable flask made of Pyrex equipped with a baffle, 150 g of [phosphate ester 1] and hydrochloric acid were added to an aqueous phase of “rinse 1” of Comparative Example 1 as a washing solution, and 0.09 g of hydrochloric acid was added.
5 g of the liquid adjusted to a specified concentration was charged, and the mixture was stirred at a speed of 200 rpm for 30 minutes using a Teflon screw blade having a blade length of 30 mm while heating at 80 ° C. in a hot water bath, and then stirring was stopped. After allowing to stand at the same temperature for 30 minutes, the aqueous phase was extracted (washing). 150 g of the aqueous phase of “Rinse 2” of Comparative Example 1 was added to the flask, mixed and stirred for 30 minutes while heating to 80 ° C., and allowed to stand for 30 minutes to extract the aqueous phase (rinse 1). Further, 150 g of distilled water was added, and the mixture was stirred and the aqueous phase was separated in the same manner (rinse 2).

In a similar apparatus, [phosphate ester 1] 13
0 g and 130 g of a solution adjusted to a 0.05N concentration by adding hydrochloric acid to the aqueous phase of "Rinse 1" as a washing solution were charged, and the washing was carried out in the same manner as described above. Comparative Example 1
Rinsing was performed twice in the same manner as in "Rinse 2", except that the aqueous phase of "Rinse 2" was used instead of the aqueous phase of "Rinse 2".

In a similar apparatus, [phosphate 1] 10
0 g and 100 g of a solution adjusted to a 0.05N concentration by adding hydrochloric acid to the aqueous phase of “Rinse 1” as a washing solution were charged, and the washing was carried out in the same manner as described above. Comparative Example 1
Rinsing was performed twice in the same manner as in "Rinse 2", except that the aqueous phase of "Rinse 2" was used instead of the aqueous phase of "Rinse 2".

Table 3 shows the results of the analysis of the wastewater (see FIG. 1) and the phosphate ester after "washing" and after "rinsing 2". FIG. 1 is a diagram illustrating the flow of the phosphate ester phase and the aqueous phase during washing and rinsing.

[0037]

Example 2 and Comparative Example 2 Washing and rinsing were carried out in the same apparatus and operating conditions as in Example 1 and Comparative Example 1, except that [phosphate ester 2] was used instead of [phosphate ester 1]. Table 4 shows the results.

[0038]

Example 3 and Comparative Example 3 [Phosphate 3] was used in place of [Phosphate 1], the operating temperature was 60 ° C.,
Washing and rinsing were carried out using the same apparatus and operation as in Example 1 and Comparative Example 1, except that the washing water was oxalic acid solution adjusted to 0.2 N. Table 4 shows the results.

[0039]

Example 4 and Comparative Example 4 Washing and rinsing were performed under the same apparatus and operating conditions as in Example 1 and Comparative Example 1, except that the washing water was a sodium hydroxide solution prepared at 0.5 N. . Table 4 shows the results.

[0040]

EXAMPLE 5 and COMPARATIVE EXAMPLE 5 An aqueous solution obtained by adding 0.5 mol / l of phosphoric acid and 0.75 mol / l of sodium hydroxide to washing water was used. Example 1 and Comparative Example 1 except that the components were removed.
Washing and rinsing were carried out under the same apparatus and operating conditions as in.
Table 4 shows the results.

[0041]

[Comparative Example 6] 300 ml Pyrex with baffle
150 g of [Phosphate 1] in a separable flask
And 150 g of distilled water as a washing solution,
While heating to 0 ° C., using a Teflon screw blade having a blade length of 30 mm, mixing and stirring were performed at a speed of 200 rpm for 30 minutes, the stirring was stopped, the mixture was allowed to stand at the same temperature for 30 minutes, and the aqueous phase was extracted. (Washing). 150 g of distilled water was added to the flask, mixed and stirred for 30 minutes while heating to 90 ° C., and allowed to stand for 30 minutes to extract an aqueous phase. The same rinsing operation was repeated once. Table 4 shows the results.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

According to the present invention, the catalyst-derived metal component can be removed from the synthesized phosphate ester oligomer by a simple method without lowering the product yield. Moreover, the wastewater is clear and contains little phenols or phosphates, and is easy to treat.

[Brief description of the drawings]

FIG. 1 is an illustration of the flow of a phosphate ester phase and an aqueous phase of Example 1 and Comparative Example 1.

[Explanation of symbols]

A. Components added to prevent emulsification during washing

Claims (4)

[Claims] 1. A method for removing a catalytic metal component and a chlorine component from an aryl phosphate ester oligomer obtained by reacting phosphorus oxychloride with a dihydric phenol and a monohydric phenol in the presence of a metal chloride catalyst. A washing and purifying step comprising a washing step of extracting and separating a metal into an aqueous phase with washing water that does not form an emulsion, and a rinsing step of rinsing metal and chlorine contained in water remaining together with the phosphate ester phase. 3. The method for cleaning phosphate esters according to claim 1, wherein waste water generated in the rinsing step is reused as washing water. 2. The method according to claim 1, wherein the washing water is acidic water having a pH of 2.6 or less. 3. The method according to claim 1, wherein the washing water contains a water-soluble hydrogen phosphate at a concentration of 0.3 mol / liter or more. 4. The method for cleaning a phosphate according to claim 1, wherein the washing water is alkaline water having a pH of 12.5 or more.