JP5668319B2 - Method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane - Google Patents

Description

  The present invention relates to a method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane (sometimes referred to herein as “bisphenol AF”) using phenol and hexafluoroacetone as starting materials, and more Specifically, it relates to an improvement in reaction yield.

  2,2-bis (4-hydroxyphenyl) hexafluoropropane is an important substance as a cross-linking agent for fluororubber, a functional polymer, and an intermediate for medical and agricultural chemicals. Bisphenol AF has been reported to be obtained by reacting hexafluoroacetone and phenol in the presence of a catalyst. In this method, organic acids such as toluenesulfonic acid and trifluoromethanesulfonic acid (Patent Document 1) and hydrogen fluoride (Non-Patent Document 1 and Patent Document 2) have been proposed as catalysts. Further, Patent Document 3 discloses that bisphenol AF is similarly obtained even when hexafluoropropylene oxide, which is a precursor of hexafluoroacetone, and phenol are used as raw materials and hydrogen fluoride is used as a catalyst or solvent.

As a typical production method, 1.26 mol of phenol, 8 mol of anhydrous hydrofluoric acid, and 0.63 mol of hexafluoroacetone were added at 100 ° C. under a reaction pressure of 0.8 to 1.0 MPa (8 to 10 kg / cm ² ). Patent Document 4 describes that bisphenol AF is obtained with a yield of 85% after stirring and reacting for a period of time and washing with water.

U.S. Pat. No. 4,400,756 JP-A-7-126200 US Pat. No. 4,358,624 Japanese Patent Laid-Open No. 2-53747

Izv Akad Nauk SSSR Otd Khim Nauk vol.4 pp.686-692 (1960); English version pp.647-653

  Conventionally, in a method for producing bisphenol AF which is industrially performed, hexafluoroacetone and phenol are reacted in hydrogen fluoride at a temperature of usually about 100 ° C. and a reaction pressure of about 1.0 MPa. Under these reaction conditions, a reaction time of 2 hours or more, and the reaction product obtained contains unreacted phenol, various reaction by-products and hydrogen fluoride. Although bisphenol AF is obtained, the yield is not necessarily as high as about 85% as can be seen from the above typical example, and it is not at a satisfactory level.

In addition, it is known that removal of water-soluble compounds such as phenol in the product is easy by washing with water and the effect of purification is high, but wastewater containing organic substances such as phenol dissolved in the washing water is also known. This increases the burden on the environment, so consideration is required.

Therefore, in the present invention, in the production method using hexafluoroacetone, phenol and hydrogen fluoride, the yield of bisphenol AF can be improved while applying a simple purification method, and the burden on the environment can be reduced. A manufacturing method is provided.

  The inventors of the present invention examined past reported examples of a method of synthesizing bisphenol AF by reacting hexafluoroacetone with phenol in the presence of hydrogen fluoride, and found that phenol / hexafluoroacetone / fluorination in the reaction system. It has been found that the ratio of hydrogen is greatly related to the composition of the product and the yield of bisphenol AF, and has a great influence on the amount of organic substances contained in the wastewater generated by water washing in the purification process.

Further, the inventors have found that unreacted hexafluoroacetone and hydrogen fluoride used in a large amount can be easily recovered after the reaction and can be used again for the reaction, and the present invention has been achieved.

That is, the present invention is as follows.
[Invention 1] A method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane comprising a reaction step of reacting hexafluoroacetone and phenol in the presence of hydrogen fluoride,
At the start of the reaction, a reaction step of 0.55 to 2 times mol of hexafluoroacetone and 8 to 200 times mol of hydrogen fluoride with respect to 1 mol of phenol;
The reactor contents obtained in the above reaction step were divided into a distillate composed of hexafluoroacetone and hydrogen fluoride, “2,2-bis (4-hydroxyphenyl) hexafluoropropane, water, and hydrogen fluoride. A column bottom liquid containing ", a distillation step to separate into,
A purification step of contacting the bottom liquid with water;
Have
The tower bottom temperature in the distillation step is 20 to 100 ° C.
A method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane .
[Invention 2] 2,2-bis (4-hydroxyphenyl) hexafluoropropane according to Invention 1, wherein the distillate separated in the distillation step is used as all or part of the hexafluoroacetone and the hydrogen fluoride. Manufacturing method.

[ Reference Invention 1] A process for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane comprising a reaction step of reacting hexafluoroacetone and phenol in the presence of hydrogen fluoride, at the start of the reaction A process for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane, comprising a reaction step of 0.55 to 2 times mol of hexafluoroacetone and 8 to 200 times mol of hydrogen fluoride with respect to 1 mol of phenol.

[ Reference Invention 2] From the reactor contents obtained in the reaction step, a distillate composed of hexafluoroacetone and hydrogen fluoride and a bottom liquid containing 2,2-bis (4-hydroxyphenyl) hexafluoropropane The manufacturing method of the reference invention 1 which has the distillation process to isolate | separate.

[ Reference Invention 3] The production method of Reference Invention 2, wherein the distillation step is performed at a temperature lower than the reaction temperature.

Reference Invention 4] The content of hydrogen fluoride bottom liquid withdrawn to the outside in the distillation process of 2,2-bis (4-hydroxyphenyl) hexafluoropropane 1 mol to 3 to 40 moles Reference Invention 2 or 3. Manufacturing method of 3.

[ Reference invention 5] The production method of Reference invention 2 or 3, wherein the content of hydrogen fluoride in the bottom liquid extracted outside in the distillation step is 5 to 20 moles per mole of water.

[ Reference Invention 6] The method of any one of Reference Inventions 2 to 5, further comprising a purification step of bringing the bottom liquid into contact with water.

[ Reference Invention 7] The production method according to any one of Reference Inventions 2 to 6, wherein the distillate separated in the distillation step is used as all or part of hexafluoroacetone and hydrogen fluoride.

  According to the method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane of the present invention, the yield of 2,2-bis (4-hydroxyphenyl) hexafluoropropane can be increased. Further, unreacted hexafluoroacetone and hydrogen fluoride can be recovered as a mixture containing no undesirable components, and can be used in the production method of the present invention. In addition, since it is possible to reduce the content of organic matter (chemical oxygen demand, hereinafter referred to as “COD”) in the wastewater generated in the purification process, large-scale 2,2-bis (4- Suitable as a method for producing hydroxyphenyl) hexafluoropropane.

  Hereinafter, the present invention will be described in detail. Although the method of this invention can be implemented by any of a batch type, a continuous type, and a semibatch type, a batch type is demonstrated in the following description. In the case of carrying out in a continuous or semi-batch mode, those skilled in the art can appropriately change the reaction apparatus and reaction conditions according to common knowledge in this technical field.

2,2-bis (4-hydroxyphenyl) hexafluoropropane can be synthesized by reacting hexafluoroacetone and phenol in the presence of hydrogen fluoride.

  In this reaction, 0.5 mol of hexafluoroacetone is equivalent to 1 mol of phenol, so that the starting material may theoretically be 0.5 mol of hexafluoroacetone per mol of phenol. However, in the method of the present invention, hexafluoroacetone can be 0.5 mol or more per mol of phenol, usually 0.55 to 2 mol is used, and 0.6 to 1 mol is preferable. More preferred is 65 to 0.9 mol. In this reaction method, unreacted hexafluoroacetone can be easily recovered and reused. When it exceeds 1 mol, the polyadduct of hexafluoroacetone increases, which is not preferable. When the amount used is less than 0.5 mol, the reaction rate decreases and the treatment takes a long time. Also, the conversion rate of phenol is remarkably decreased and unreacted phenol remains, and the wastewater in the purification process by water washing. This is not preferable because the amount of organic matter in the medium increases.

  Hexafluoroacetone can be produced by a known method. For example, it can be produced by a method of fluorinating hexachloroacetone with hydrogen fluoride in the presence of a chromium-supported activated carbon catalyst or a method of isomerizing hexafluoropropene epoxide obtained by oxidizing hexafluoropropene. When used in the method of the present invention, hexafluoroacetone can be used as a simple substance, a hydrogen fluoride adduct or a hydrogen fluoride solution.

  In the production method of the present invention, 8 mol or more of hydrogen fluoride is used per 1 mol of phenol. Preferably it is 10 mol or more, More preferably, it is 15 mol or more, More preferably, it is 25 mol or more.

The upper limit of the amount of hydrogen fluoride used is not limited in principle, but is practically preferably 200 mol or less, more preferably 100 mol or less, from the viewpoint of the efficiency of the reactor, etc. More preferably, it is less than or equal to mol. Usually, about 8-100 mol is preferable and about 10-50 mol is the most preferable.

  Although the amount of water contained in hydrogen fluoride used in the present invention is preferably small, hydrogen fluoride (hydrofluoric acid) that is usually produced and supplied for industrial use can be used. Further, hydrogen fluoride recovered from the liquid in the reactor by the production method of the present invention can be used as it is without being purified or purified. A commercially available phenol can be used, but a phenol having a low water content is preferred. As can be seen from the fact that hydrogen fluoride does not appear in the above reaction formula, hydrogen fluoride functions as a catalyst or a solvent rather than as a reaction substrate and plays an important role in this reaction.

  The method of the present invention is carried out at a reaction temperature of 50 to 200 ° C, preferably 70 to 150 ° C, more preferably 80 to 120 ° C. If it is 50 ° C. or lower, the reaction is slow, and if it exceeds 200 ° C., a reaction apparatus that can withstand a large reaction pressure is required, and coloring of products and generation of impurities increase, which is not preferable.

  The reaction according to the present invention is carried out by charging phenol, hydrogen fluoride, and hexafluoroacetone in a reactor and heating them at a predetermined temperature for a predetermined time. At that time, self-pressure is generated. The reaction pressure mainly depends on the vapor pressure of hydrogen fluoride corresponding to the reaction temperature, but is preferably 0.2 to 2 MPa. The reaction is carried out in a pressure vessel made of a material resistant to hydrogen fluoride. As the material of the reactor, stainless steel, nickel, Monel (TM), Inconel (TM), platinum, silver, fluororesin, etc. can be used, and these materials or materials obtained by lining these materials can be used.

  The reaction time in the method of the present invention is approximately 5 minutes to 20 hours, preferably 10 minutes to 10 hours, and more preferably 20 minutes to 5 hours. If the reaction time is less than 5 minutes, a sufficient reaction yield cannot be obtained, and exceeding 20 hours is not preferable because by-products increase due to the secondary reaction.

In the method of the present invention, after the hexafluoroacetone is consumed and the addition reaction of phenol and hexafluoroacetone is completed, the reaction is preferably terminated quickly. The final stage of the reaction is the bisphenol AF in the reaction system. It is preferable to set the time when the rate of increase becomes substantially zero, or when the concentration of phenol becomes substantially zero, for example, 1% or less.

  In the method of the present invention, it is desirable that the content of water relative to hydrogen fluoride does not exceed 3% by weight, including unintentional contamination from raw materials at the end of the reaction. The water content is more preferably 2% by mass or less, and further preferably 1% by mass or less. The water content in the reactor can be estimated from the amount of bisphenol AF produced as the reaction proceeds, and can also be measured directly by a moisture analysis method such as the Karl Fischer method. The reaction time may be determined by any of these methods.

  The method of the present invention starts by introducing the raw materials phenol, hexafluoroacetone and hydrogen fluoride into the reactor. Phenol, hexafluoroacetone and hydrogen fluoride may be introduced separately into the reactor, but phenol and hexafluoroacetone can also be introduced by dissolving each in hydrogen fluoride, or phenol, hexafluoroacetone and hydrogen fluoride. Hydrogen fluoride can also be mixed outside the reactor and introduced into the reactor. Thereafter, the reactor is kept at a predetermined temperature for the necessary time to complete the reaction. The reactor contents may or may not be stirred, but stirring is preferred to shorten the reaction time.

  After completion of the reaction, the reactor contents include bisphenol AF, hydrogen fluoride, hexafluoroacetone, water, and other by-products. In order to obtain bisphenol AF from the reactor contents, any method may be used. As a conventional method, for example, the reactor contents are poured into water as they are, and an acidic component or a water-soluble organic substance is used. And a method of obtaining solid bisphenol AF by dissolution and removal, and a method of obtaining a solid by distilling off acid and volatile components from the reaction product. Moreover, the method of obtaining bisphenol AF by distilling phenol etc. off by subsequent steam distillation of this obtained solid is mentioned.

  In the method of the present invention, it is preferable to distill and separate unreacted hexafluoroacetone and hydrogen fluoride from the reactor contents at a temperature lower than the reaction temperature after completion of the reaction. Removal of hydrogen fluoride and hexafluoroacetone from the reactor contents can be performed by simple distillation or rectification, and distillation can be performed batchwise or continuously. In the following, batch distillation will be described as an example, but it is easy for those skilled in the art to determine the conditions for continuous distillation based on the description of the present specification. The distillation apparatus is not particularly limited, and a normal distillation apparatus can be applied, but a precision distillation apparatus is more suitable than a single distillation apparatus. The reactor product is introduced into the bottom or middle of the distillation column, and hydrogen fluoride and hexafluoroacetone are removed from the top of the column, and a mixture of bisphenol AF, water and hydrogen fluoride is obtained from the bottom. By doing in this way, unlike the case where the reaction liquid after the reaction is evaporated to dryness (Non-Patent Document 1), the mixture of hexafluoroacetone and hydrogen fluoride does not contain other undesirable components, and Bisphenol AF exhibits a very advantageous effect in operation that it can be handled as a liquid.

  In distillation, maintaining the temperature close to the reaction temperature for a longer time than necessary after the reaction may increase the amount of by-products, so the column bottom temperature is distilled at a temperature lower than the reaction temperature, and the column bottom temperature is 20 It is set to -100 degreeC and 20-50 degreeC is preferable. Since the column bottom liquid contains bisphenol AF, it is necessary to carry out the distillation operation at a column bottom temperature higher than the temperature corresponding to the vapor pressure indicated by the hydrogen fluoride aqueous solution. In the case of using a sufficiently dehydrated reaction system at the start of the reaction, the content of bisphenol AF and the content of water are 1 in molar ratio, so that under these conditions, the temperature corresponds to the vapor pressure indicated by the aqueous hydrogen fluoride solution. The column bottom temperature is generally about 5 to 25 ° C, usually about 10 to 20 ° C. When there is intentional or unintentional mixing of water from the outside, the column bottom temperature is different, but the temperature can be determined by observing the state of distillation. Usually, distillation is performed near atmospheric pressure, but it may be performed under reduced pressure or pressure of about 0.05 to 2 MPa. The temperature at the top of the column is 20 ° C. or lower, preferably 10 to 20 ° C., more preferably adjusted to about 14 to 20 ° C. Since HFA forms a complex with HF, a distillate can be obtained as the complex or a mixture of the complex and HF. Hydrogen fluoride and hexafluoroacetone recovered from the top of the column are substantially free of other components and can be reused as they are in the production method of the present invention without any purification.

  An aqueous solution containing hydrogen fluoride and bisphenol AF (column bottom liquid) can be obtained from the column bottom. By setting the tower bottom temperature within the above temperature range, the composition of hydrogen fluoride in the tower bottom liquid after distillation is preferably 3 to 40 moles of hydrogen fluoride with respect to 1 mole of bisphenol AF. Mole is more preferable, and 5 to 20 mol is particularly preferable. If the molar ratio of hydrogen fluoride is less than 3, it is not preferable because bisphenol AF is not sufficiently dissolved in the hydrogen fluoride aqueous solution and is inconvenient to handle. If it exceeds 40 mol, a large amount of organic substance-containing hydrogen fluoride aqueous solution that is difficult to recover can be obtained. Since it will occur, it is not preferable. Moreover, about 5-20 mol hydrogen fluoride exists with respect to 1 mol of water in the column bottom liquid after the said distillation. Since water and hydrogen fluoride azeotrope at about 114 ° C., water is not substantially mixed into hydrogen fluoride and hexafluoroacetone distilled from the top of the column.

  From a hydrogen fluoride aqueous solution of bisphenol AF recovered from the bottom of the tower, a conventionally known method is applied, for example, a purification method in which the bottom liquid is thrown into water to remove residual hydrogen fluoride and water-soluble organic substances. Thus, solid bisphenol AF can be obtained. This solid may contain various intermediate products, isomers of bisphenol AF, and in some cases, unreacted phenol, etc., but phenol or monophenol (a compound in which one hexafluoroisopropanol group is substituted on the benzene ring of phenol) Is water-soluble and can be removed from bisphenol AF by washing with water, and bisphenol AF can be obtained with a purity of 95% or more, usually 98% or more.

The washing water used in the water washing contains water-soluble phenol, monophenol and the like, and the amount of organic matter (chemical oxygen demand COD) is generated in the waste water.

  The bisphenol AF obtained here can be further purified by various known methods. For example, crude bisphenol AF is dissolved in an aqueous solution of a basic compound such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium bicarbonate, potassium bicarbonate, calcium oxide, and the like. By adding a mineral acid such as hydrochloric acid or nitric acid to precipitate bisphenol AF, it can be filtered to obtain purified bisphenol AF. Moreover, it can refine | purify also by heating bisphenol AF and water to normal temperature (about 25 degreeC) or more, and cooling and precipitating a solution. The obtained purified bisphenol AF can be dried by a known means.

  Hexafluoroacetone and hydrogen fluoride obtained by separation in the distillation step can be used as all or part of the raw materials, hexafluoroacetone and hydrogen fluoride as the catalyst in the production method of the present invention. Normally, hexafluoroacetone can be handled as a hydrogen fluoride solution, but it can be further distilled and used as each component.

  EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Table 1 summarizes the results. In the following, analysis of organic substances is performed by gas chromatograph using an FID detector, and “%” represents “area%”.

[Example 1]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature dropped to 10 ° C. or lower, 240.6 g (12.03 mol) of hydrogen fluoride (hereinafter abbreviated as “HF”) was charged, and then hexafluoroacetone (hereinafter abbreviated as “HFA”). 80.1 (0.48 mol) was charged (molar ratio of HFA to phenol: 0.6, molar ratio of HF: 15). The internal temperature was raised to 110 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 2 hours after the internal temperature reached 110 ° C. The internal pressure at this time was 1.15 to 1.09 MPa. When the composition of the reaction liquid (organic substance) at this time was analyzed, the target product, bisphenol AF, was 95.9%. In addition, the raw material phenol was 0.9%, the intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol was 0.1%, and the intermediate isomer 2- (2 -Hydroxyphenyl) hexafluoropropan-2-ol was 2.0%, the isomer of bisphenol AF was 0.7%, the HFA adduct of bisphenol AF was 0.3%, and the others were 0.1%.

  After completion of the reaction, the reaction solution is cooled to 30 ° C. or less in an ice bath, and the whole reaction solution is extracted from the extraction tube connected to the siphon tube in a polyethylene container containing about 1800 g of water by holding pressure and nitrogen pressurization. A solid was precipitated. The precipitated solid was filtered and further washed twice with about 650 g of water to obtain bisphenol AF having a purity of 98.5%. When this was dried, 116.1 g of bisphenol AF was obtained, and the yield at this time was 92.5%. Further, when the washing water was measured according to JIS K0102, the COD value was 9375 mg / L.

[Example 2]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature dropped to 10 ° C. or less, HF 241.4 g (12.07 mol) was charged, and then HFA 106.3 (0.64 mol) was charged (molar ratio of HFA to phenol: 0.8, molar ratio of HF). 15). The internal temperature was raised to 90 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 3 hours after the internal temperature reached 90 ° C. The internal pressure at this time was 0.75 to 0.69 MPa. Analysis of the composition of the reaction solution (organic matter) at this time revealed that the target product, bisphenol AF, was 95.7%. In addition, the intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol is 0.3%, and the intermediate isomer 2- (2-hydroxyphenyl) hexafluoropropan-2-ol. All was 3.4%, bisphenol AF isomer was 0.2%, and the others were 0.4%.

  After completion of the reaction, the reaction solution is cooled to 30 ° C. or less in an ice bath, and the whole reaction solution is extracted from the extraction tube connected to the siphon tube in a polyethylene container containing about 1800 g of water by holding pressure and nitrogen pressurization. A solid was precipitated. The precipitated solid was filtered and further washed twice with about 650 g of water to obtain bisphenol AF having a purity of 99.0%. When this was dried, 109.9 g of bisphenol AF was obtained, and the yield at this time was 94.0%. Further, when the washing water was measured according to JIS K0102, the COD value was 8055 mg / L.

[Example 3]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature decreased to 10 ° C. or less, HF 241.2 g (12.06 mol) was charged, and then HFA 106.9 (0.64 mol) was charged (hexafluoroacetone to phenol molar ratio 0.8, HF Molar ratio 15). The internal temperature was raised to 100 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 2 hours after the internal temperature reached 100 ° C. The composition of the reaction liquid (organic substance) at this time was 96.5% of 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), which is the target product. In addition, 0.1% phenol, 0.1% intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol, and 2- (2-hydroxy) intermediate isomer Phenyl) hexafluoropropan-2-ol was 2.6%, the isomer of bisphenol AF was 0.3%, the HFA adduct of bisphenol AF was 0.4%, and the others were 0.1%.

  After completion of the reaction, the reaction solution is distilled and separated using an HFA / HF recovery tower (hereinafter referred to as “recovery tower”), and the bottom containing a distillate composed of unreacted hexafluoroacetone and hydrogen fluoride and bisphenol AF. Separated into liquid. As the material for the recovery tower, fluororesin or polyethylene was used. The distillation pot (bottom) uses a polytetrafluoroethylene container, the distillation tower uses a PFA column filled with polyethylene Raschig rings as a filler, and a PFA cylindrical container with a snake tube that flows a refrigerant inside. A 500 ml PFA container was used as a receiver for the distillate from the top of the column.

  The autoclave is cooled to 30 ° C or lower in an ice bath, and the extraction valve at the outlet of the siphon tube provided in the autoclave and the transfer valve provided at the bottom of the recovery tower (capacity: 500 mL) are connected by piping. 404.7 g of the reaction solution was transferred under pressure. A -15 ° C refrigerant was passed through a condenser in the recovery tower in advance at the time of liquid transfer to cool it, so that HFA and HF did not escape outside the system at the time of liquid transfer. After the transfer, the autoclave was removed and the recovery tower bottom was heated in an oil bath set at 40 ° C. After about 20 minutes, total reflux of the HFA / HF mixture began. At this time, the internal temperature at the bottom was 24.4 ° C., and the temperature at the top of the recovery tower was 17.0 ° C. After maintaining the total reflux for 30 minutes, the extraction was started. At the time of extraction, reflux was performed at a reflux ratio (reflux: distillation) = 10 seconds: 5 seconds so that the temperature at the top of the column was 20 ° C. or less. After the start of extraction, the temperature of the oil bath was increased to 50 ° C. at a rate of 5 ° C./30 minutes. When the internal temperature of the bottom reached 38 ° C., the recovery of HFA / HF was completed to complete the extraction, the bottom oil bath was removed, and the bottom was cooled to 20 ° C. or lower in an ice bath. After cooling, the bottom residual liquid was completely removed from the siphon tube by nitrogen pressurization in a polyethylene container containing 900 g of water to precipitate a solid. The precipitated solid was filtered and washed twice with about 450 g of water to obtain bisphenol AF having a purity of 98.5%. When this was dried, the yield of bisphenol AF was 94.2%. The weight of the recovered distillate was 162.4 g, and the composition was analyzed to find HF 130.1 g and HFA 32.3 g. 56.4% by mass of HF was recovered with respect to the charged mass, and 83.4% by mass of the theoretical amount of HFA was recovered. Further, when the washing water was measured according to JIS K0102, the COD value was 8686 mg / L.

[Example 4]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature dropped to 10 ° C. or lower, 241.0 g (12.05 mol) of HF was charged, and then 106.3 (0.64 mol) of HFA was charged (a molar ratio of hexafluoroacetone to phenol of 0.8, Molar ratio 15). The internal temperature was raised to 100 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 2 hours after the internal temperature reached 100 ° C. The composition of the reaction solution (organic matter) at this time was 96.2% of 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), which was the object of analysis. In addition, 0.1% phenol, 0.1% intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol, and 2- (2-hydroxy) intermediate isomer Phenyl) hexafluoropropan-2-ol was 2.9%, the isomer of bisphenol AF was 0.4%, the HFA adduct of bisphenol AF was 0.2%, and the others were 0.1%.

  After completion of the reaction, the autoclave is cooled to 30 ° C or less in an ice bath, and a pipe connecting the extraction valve at the outlet of the siphon tube provided in the autoclave and the transfer valve provided at the bottom of the collection tower (capacity 500 mL). 388.4 g of the reaction solution was transferred under holding pressure and nitrogen pressurization. A refrigerant at −15 ° C. was passed through a condenser in the HFA / HF recovery tower in advance at the time of transfer to cool it, so that HFA and HF did not escape from the system at the time of transfer. After the transfer, the autoclave was removed and the recovery tower bottom was heated in an oil bath set at 40 ° C. After about 20 minutes, total reflux of the HFA / HF mixture began. At this time, the internal temperature at the bottom was 25.2 ° C., and the temperature at the top of the recovery tower was 16.9 ° C. After maintaining the total reflux for 30 minutes, the extraction was started. At the time of extraction, reflux was performed at a reflux ratio (reflux: distillation) = 10 seconds: 5 seconds so that the temperature at the top of the column was 20 ° C. or less. After the start of extraction, the temperature of the oil bath was increased to 50 ° C. at a rate of 5 ° C./30 minutes. When the bottom internal temperature reached 42 ° C., the recovery of HFA / HF was terminated and the extraction was completed, the bottom oil bath was removed, and the bottom was cooled to 20 ° C. or less in an ice bath. After cooling, the bottom residual liquid was completely removed from the siphon tube by nitrogen pressurization in a polyethylene container containing 900 g of water to precipitate a solid. The precipitated solid was filtered and washed twice with about 450 g of water to obtain bisphenol AF having a purity of 99.1%. When this was dried, the yield of bisphenol AF was 95.0%. The weight of the recovered distillate was 179.0 g, and the composition was analyzed to find HF 147.8 g and HFA 32.3 g. 6.7% by mass of HF was recovered with respect to the charged mass, and 84.8% by mass of the theoretical amount of HFA was recovered. Further, when the washing water was measured according to JIS K0102, the COD value was 9413 mg / L.

[Example 5]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature decreased to 10 ° C. or lower, 162.8 g (HF: 133.6) of HF and HFA mixture (HF: HFA molar ratio = 97.4: 2.6) obtained by the recovery distillation of Examples 4 and 5 were used. 72.5 g of HFA: 29.2 g), and then 112.5 g (12.31 mol) of HF and 77.9 g (0.47 mol) of HFA were charged (molar ratio of HFA to phenol was 0.8, mol of HF). Ratio 15). The internal temperature was raised to 100 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 2 hours after the internal temperature reached 100 ° C. The internal pressure at this time was 0.95 to 0.88 MPa. The composition of the reaction solution (organic substance) at this time was 95.9% for bisphenol AF, which was the target product. In addition, the raw material phenol is 0.1%, the intermediate 2-hydroxy-2- (4-hydroxyphenyl) hexafluoropropane is 0.1%, and the intermediate isomer 2- Hydroxy-2- (2-hydroxyphenyl) hexafluoropropane was 3.1%, the isomer of bisphenol AF was 0.3%, and the others were 0.5%.

After completion of the reaction, the reaction solution is cooled to below 30 ° C in an ice bath, and the whole reaction solution is extracted from the extraction valve with a siphon tube in a polyethylene container containing about 1800 g of water by holding pressure and nitrogen pressurization. A solid was precipitated. The precipitated solid was filtered and washed twice with about 650 g of water to obtain bisphenol AF having a purity of 99.1%. When this was dried, it was 114.3 g. The yield of bisphenol AF at this time was 93.1%. Further, when the washing water was measured according to JIS K0102, the COD value was 6056 mg / L.

[Comparative Example 1]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature decreased to 10 ° C. or less, 96.8 g (4.84 mol) of hydrogen fluoride (HF) was charged, and then 68.1 (0.41 mol) of hexafluoroacetone (HFA) was charged (based on phenol). A molar ratio of hexafluoroacetone 0.51 and a molar ratio of hydrogen fluoride 6). The internal temperature was raised to 98 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 5 hours after the internal temperature reached 98 ° C. The composition of the reaction liquid (organic substance) at this time was 90.9% for 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), which is the target product. In addition, 1.7% of phenol, 2.4% of the intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol, 2- (2-hydroxy) which is an isomer of the intermediate Phenyl) hexafluoropropan-2-ol was 4.3%, the isomer of bisphenol AF was 0.2%, and the others were 0.5%.

After completion of the reaction, the reaction solution is cooled to below 30 ° C in an ice bath, and the whole reaction solution is extracted from the extraction valve with a siphon tube in a polyethylene container containing about 1800 g of water by holding pressure and nitrogen pressurization. A solid was precipitated. The precipitated solid was filtered and washed twice with about 650 g of water to obtain bisphenol AF having a purity of 99.6%. When this was dried, it was 115.3 g. The yield of bisphenol AF at this time was 85.8%. Further, when the washing water was measured according to JIS K0102, the COD value was 30318 mg / L.

[Comparative Example 2]
In a 500 mL autoclave made of stainless steel equipped with a stirrer, gas introduction valve, thermocouple, pressure gauge, and siphon tube, 75.2 g (0.80 mol) of molten phenol was charged and cooled in an ice bath. When the internal temperature dropped to 10 ° C. or less, HF 321.5 g (16.08 mol) was charged, and then HFA 66.9 (0.40 mol) was charged (0.5 molar ratio of HFA to phenol, molar ratio of HF). 20). The internal temperature was raised to 98 ° C. while the autoclave was sealed and stirred, and the reaction was continued for 5 hours after the internal temperature reached 98 ° C. The composition of the reaction solution (organic substance) at this time was 92.4% of 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), which is the target product. In addition to this, 4.1% of phenol, 0.2% of the intermediate 2- (4-hydroxyphenyl) hexafluoropropan-2-ol, and 2- (2-hydroxy) which is an isomer of the intermediate Phenyl) hexafluoropropan-2-ol was 2.4%, the isomer of bisphenol AF was 0.5%, and the others were 0.4%.

After completion of the reaction, the reaction solution is cooled to below 30 ° C in an ice bath, and the whole reaction solution is extracted from the extraction valve with a siphon tube in a polyethylene container containing about 1800 g of water by holding pressure and nitrogen pressurization. A solid was precipitated. The precipitated solid was filtered and washed twice with about 650 g of water to obtain bisphenol AF having a purity of 99.7%. When this was dried, it was 114.6g. The yield of bisphenol AF at this time was 85.3%. Further, when the washing water was measured according to JIS K0102, the COD value was 22355 mg / L.

  It is possible to obtain 2,2-bis (4-hydroxyphenyl) hexafluoropropane (bisphenol AF), which is important as an intermediate for fluororubber crosslinking agents, functional polymers, and pharmaceuticals and agricultural chemicals.

Claims (2)

A process for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane comprising a reaction step of reacting hexafluoroacetone and phenol in the presence of hydrogen fluoride,
At the start of the reaction, a reaction step of 0.55 to 2 times mol of hexafluoroacetone and 8 to 200 times mol of hydrogen fluoride with respect to 1 mol of phenol ;
The reactor contents obtained in the above reaction step were divided into a distillate composed of hexafluoroacetone and hydrogen fluoride, “2,2-bis (4-hydroxyphenyl) hexafluoropropane, water, and hydrogen fluoride. A column bottom liquid containing ", a distillation step to separate into,
A purification step of contacting the bottom liquid with water;
Have
The tower bottom temperature in the distillation step is 20 to 100 ° C.
A method for producing 2,2-bis (4-hydroxyphenyl) hexafluoropropane. The distillate separated in the distillation process, the production method of 2,2-bis (4-hydroxyphenyl) hexafluoropropane according to claim 1 for use as all or part of the hexafluoroacetone and said hydrogen fluoride .