Method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, method for producing polyamide polymer, and method for producing polybenzoxazole

Abstract

To provide a 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane production process in which the amount of impurities can be reduced.SOLUTION: In the production process including a solution preparation step of preparing a homogeneous solution in which 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (compound 1) containing impurities is dissolved in a solvent, and a recrystallization step of recrystallizing the compound 1 dissolved in a solution to obtain a powder of the compound 1, the solvent contains at least the following first solvent and second solvent. First solvent: a solvent in which the solubility of the compound 1 at 23°C is 0.05 to 3.0 g [g / 10 g] and the solubility of the compound 1 at 80°C is 0.2 to 6.0 g [g / 10 g]. Second solvent: a solvent in which the solubility of the compound represented by formula (2) at 23°C is 2.6 [g / 10 g] or more, and / or the solubility of the compound represented by formula (3) at 23°C is 2.2 [g / 10 g] or more.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, a polyamide polymer, and a method for producing polybenzoxazole. [Background technology]

[0002] 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, represented by the following formula (1), is an important compound used as a raw material for functional polymers such as polyimide, polyamide, polybenzoxazole, etc. The functional polymers synthesized using these as raw materials exhibit excellent heat resistance, insulating properties, and low dielectric constant, and are used in many insulating materials for semiconductors.

[0003] [ka]

[0004] There are several documents known about the process and method for the preparation of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

[0005] Patent Document 1 describes a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, in which a bisnitro compound is reduced with hydrogen or hydrazine. Patent Documents 2 to 4 describe a method for purifying 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (a method for reducing impurities). Specifically, they describe a method for reducing impurities by dissolving 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in a polar solvent and adding a poor solvent to the solution to form a two-component crystallization process. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 11-106367 [Patent Document 2] JP 2012-184173 A [Patent Document 3] Japanese Patent Application Publication No. 11-100356 [Patent Document 4] JP 2004-131386 A Summary of the Invention [Problem to be solved by the invention]

[0007] The present inventors have found that conventional 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane contains non-negligible amounts of impurities, as described below, and that these impurities act as polymerization inhibitors when producing a functional polymer using 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane as a raw material, and can adversely affect the quality of the final product, that is, the functional polymer material.

[0008] Specifically, when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is produced by a method of reducing a bisnitro compound with hydrogen or hydrazine as in Patent Document 1, a non-negligible amount of a compound represented by formula (2) in which one of the amino groups of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is replaced with hydrogen (hereinafter, sometimes referred to as a monoamino compound) may be produced as a by-product, depending on the reaction conditions.

[0009] [ka]

[0010] In addition, according to the findings of the present inventors, commonly available 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane products may contain 0.1% or more of the compound represented by formula (3) (hereinafter, also referred to as monoamino mononitro compound) as an impurity, as determined by liquid chromatography. This is presumably due to the fact that the reaction conditions were made mild in order to reduce the by-production of the above-mentioned monoamino compound, so that only one of the two nitro groups in the reaction intermediate was reduced, and not all of the nitro groups were reduced. The impurity concentration of 0.1% or more is quite high considering the uses of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and it is presumed that the monoamino-mononitro form is a compound that is difficult to remove by normal refining operations.

[0011] [ka]

[0012] As a method for reducing impurities in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, there is a two-component purification method using an alcohol as a polar solvent and water as a poor solvent, as described in the above-mentioned Patent Documents 2 to 4. However, to the extent of the preliminary investigation by the present inventors, the conventional method was insufficient in removing monoamino compounds and monoamino mononitro compounds.

[0013] The present invention has been made in view of the above circumstances. One of the objects of the present invention is to provide a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, which can reduce the amount of impurities. [Means for solving the problem]

[0014] The present inventors have completed the invention provided below and have solved the above problems.

[0015] The present invention is as follows.

[0016] A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, comprising purifying 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities to produce 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having an increased purity, comprising the steps of: The manufacturing method includes: A solution preparation step of preparing a homogeneous solution in which 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities is dissolved in a solvent; a recrystallization step of recrystallizing the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane dissolved in the solution to obtain a powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Including, A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, wherein the solvent contains at least the following first solvent and second solvent: First solvent: a solvent in which the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 23°C is 0.05 to 3.0 g [g / 10 g] and the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 80°C is 0.2 to 6.0 g [g / 10 g]. Second solvent: a solvent in which the solubility at 23°C of a compound represented by the following formula (2) is 2.6 [g / 10 g] or more, and / or the solubility at 23°C of a compound represented by the following formula (3) is 2.2 [g / 10 g] or more. [ka]

[0017] The present invention also provides the following.

[0018] 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, having a purity of 99.5% or more as determined by liquid chromatography analysis, and having a content of a compound represented by the following formula (2) of less than 0.1%: [ka]

[0019] The present invention also provides the following.

[0020] 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, having a purity of 99.5% or more as determined by liquid chromatography analysis, and having a content of a compound represented by the following formula (3) of less than 0.1%: [ka]

[0021] The present invention also provides the following.

[0022] A method for producing a polyamide polymer, comprising condensation polymerizing the above-mentioned 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with a dicarboxylic acid or a dicarboxylic acid halide to obtain a polyamide polymer.

[0023] The present invention also provides the following.

[0024] A method for producing polybenzoxazole, comprising heating the polyamide polymer produced by the method for producing a polyamide polymer described above to obtain polybenzoxazole. Effect of the Invention

[0025] According to the present invention, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing a small amount of impurities can be produced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described in detail. In this specification, unless otherwise specified, the expression "X to Y" in the explanation of a numerical range means from X to Y. For example, "1 to 5% by mass" means "from 1% by mass to 5% by mass". In this specification, the "production method for 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane" may be simply referred to as the "production method".

[0027] <Method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane> The production method of this embodiment is a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having an increased purity by purifying 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities.

[0028] The manufacturing method of this embodiment includes the following steps. A solution preparation process in which 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities is dissolved in a solvent to prepare a homogeneous solution. A recrystallization step of recrystallizing the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane dissolved in the above solution to obtain a powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

[0029] Here, the solvent is a solvent containing at least the following first solvent and second solvent: First solvent: a solvent in which the solubility of 2,2-bis(3-amino-4-hydroxyphenyl) at 23°C is 0.05 to 3.0 g [g / 10 g] and the solubility of 2,2-bis(3-amino-4-hydroxyphenyl) at 80°C is 0.2 to 6.0 g [g / 10 g]. Second solvent: a solvent in which the solubility at 23°C of a compound represented by the following formula (2) is 2.6 [g / 10 g] or more, and / or the solubility at 23°C of a compound represented by the following formula (3) is 2.2 [g / 10 g] or more.

[0030] [ka]

[0031] As described above, the present inventors have found that the monoamino compound represented by formula (2) and the monoamino mononitro compound represented by formula (3) are contained as impurities in non-negligible amounts in conventional 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and can adversely affect the quality of the final product, which is a functional polymer material. Based on this finding, the present inventors have investigated a method capable of reducing the impurities of the monoamino compound represented by formula (2) and the monoamino mononitro compound represented by formula (3).

[0032] As a result of the investigation, in the process of dissolving and recrystallizing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, a solvent (second solvent) that dissolves the monoamino compound represented by formula (2) and the monoamino mononitro compound represented by formula (3) well at 23°C was added to a solvent (first solvent) that dissolves 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. This suppresses the crystallization of the monoamino compound represented by formula (2) and the monoamino mononitro compound represented by formula (3) during recrystallization. In this way, we succeeded in producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with a low content of the monoamino compound represented by formula (2) and the monoamino mononitro compound represented by formula (3).

[0033] Incidentally, in the manufacturing method of this embodiment, the fact that the solution containing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, the first solvent, and the second solvent is homogeneous is also considered to be related to the reduction of impurities. Although the details are unclear, layer separation may be observed in the solution preparation step, especially when the first solvent and the second solvent are not completely mixed. When this layer separation occurs, the amount of impurities tends not to be sufficiently reduced (see also the comparative example shown later). Whether the above solution is homogeneous or not can usually be confirmed by visual inspection. In this specification, the solution is considered to be "homogeneous" if no layer separation is visually confirmed in the solution preparation step.

[0034] The manufacturing method of this embodiment will now be described in detail.

[0035] (Solution preparation process) How to obtain 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane The method of obtaining the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities prepared in the solution preparation step is not particularly limited. Commercially available products may be purchased, or may be synthesized based on the description in a known document. Commercially available products may be purchased, for example, from Tokyo Chemical Industry Co., Ltd., Fujifilm Wako Pure Chemical Industries, Ltd., Sigma-Aldrich Japan LLC, etc.

[0036] First Solvent The first solvent only needs to have a solubility of 0.05 to 3.0 g [g / 10 g] of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 23° C. and a solubility of 0.2 to 6.0 g [g / 10 g] of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 80° C. In short, the first solvent is a solvent that does not dissolve 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane very much at about room temperature, but dissolves 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane moderately at 80° C.

[0037] The solubility of the first solvent, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 23° C. is preferably 0.05 to 3.0 g [g / 10 g], and more preferably 0.1 to 2.0 g [g / 10 g]. The solubility of the first solvent, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 80° C. is preferably 0.2 to 6.0 g [g / 10 g], and more preferably 1.0 to 5.0 g [g / 10 g].

[0038] As an example, the first solvent can include water. When water is used, the amount is, for example, 50 to 1000 parts by mass, preferably 100 to 500 parts by mass, and more preferably 150 to 400 parts by mass, relative to 100 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities. By appropriately adjusting the amount of water, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can be sufficiently dissolved and the yield can be improved.

[0039] As another example, the first solvent may include alcohols, which are believed to dissolve 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to a suitable degree due to the presence of hydroxy groups in the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

[0040] Specific examples of alcohols include C1 to C6 lower alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-2-butanol, 1-hexanol, 2-hexanol, 3-hexanol, 3-methyl-3-pentanol, cyclohexanol, etc. Among these, more preferred alcohols are methanol, ethanol, n-propanol, and isopropanol.

[0041] When alcohols are used, the amount thereof is, for example, 25 to 500 parts by mass, preferably 50 to 250 parts by mass, and more preferably 75 to 200 parts by mass, relative to 100 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities. By appropriately adjusting the amount of alcohols, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can be sufficiently dissolved and the yield can be improved.

[0042] The first solvent may be a single solvent or a mixed solvent. When the first solvent is a mixed solvent, it is sufficient that the mixed solvent satisfies the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane described above.

[0043] In this embodiment, the first solvent is preferably a mixed solvent of water and alcohols. By using the first solvent as a mixed solvent of water and alcohols, the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in the solution preparation step can be made appropriate, and the recrystallization rate in the recrystallization step can be improved. In addition, the amount of impurities other than the compound represented by formula (2) and / or the compound represented by formula (3) can be further reduced. When the first solvent is a mixed solvent of water and alcohols, the mixing ratio of water to alcohols is preferably water:alcohols=10:1 to 1:1, more preferably water:alcohols=5:1 to 2:1, in mass ratio.

[0044] Incidentally, for example, when a mixed solvent of water and IPA (isopropanol) is used as the first solvent, regardless of the mixing ratio, the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 23°C is within the range of 0.05 to 3.0 g [g / 10 g], and the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 80°C is within the range of 0.2 to 6.0 g [g / 10 g].

[0045] As a specific example, the results of evaluating the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane in a mixed solvent of water and IPA (isopropanol) are shown below. In this evaluation, first, a mixed solvent of isopropanol (IPA) and water was placed in a 50 mL flask made of borosilicate glass equipped with a stirrer and a thermometer until a total amount of 10 g was added (the mixed solvents were three different: IPA:water (mass ratio) = 1:7, 1:3, and 1:1). Next, 0.01 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was added to the mixed solvent while stirring with a stirrer, and the presence or absence of dissolution was confirmed visually. If it was dissolved, another 0.01 g was added and the presence or absence of dissolution was similarly confirmed visually. The same operation was then repeated until it was visually confirmed that it was not dissolved. By this procedure, the weight at which it was confirmed that 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was completely dissolved was measured. The temperature was 23°C and 80°C.

[0046] [Table 1]

[0047] Second Solvent The second solvent only needs to have a solubility of the compound represented by formula (2) (monoamino form) of 2.6 [g / 10 g] or more at 23° C. and / or a solubility of the compound represented by formula (3) (monoamino mononitro form) of 2.2 [g / 10 g] or more at 23° C. In short, the second solvent is a solvent that dissolves a certain amount of the compound represented by formula (2) and / or the compound represented by formula (3) at about room temperature.

[0048] The solubility of the compound represented by formula (2) (monoamino form) in the second solvent at 23° C. is preferably 2.6 to 10.0 g [g / 10 g], and more preferably 3.6 to 6.0 g [g / 10 g]. The solubility of the compound represented by formula (3) (monoamino mononitro form) in the second solvent at 23° C. is preferably 2.2 to 10.0 g [g / 10 g], and more preferably 3.0 to 6.0 g [g / 10 g].

[0049] In terms of the solubility of the compound represented by formula (2) and / or the compound represented by formula (3), the SP value can be referred to in selecting the second solvent. Specifically, the SP value of the second solvent is preferably 8.0 to 13.0 [(cal / cm 3 ) 0.5 ], more preferably 8 to 11 [(cal / cm 3 ) 0.5 By selecting a second solvent having such an SP value, it is believed that the amount of impurities in the obtained 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can be further reduced.

[0050] Just to be clear, the "SP value" in this specification is called the Solubility Parameter, and can also be called the solubility parameter. It means a value calculated using the Hansen formula shown below. The solubility parameter is divided into three components, the dispersion term δd, the polarity term δp, and the hydrogen bond term δh, and is represented in a three-dimensional space. δ[(cal / cm 3 ) 0.5 ]=(δd 2 +δp 2 +δh 2 ) 0.5

[0051] The Hansen solubility parameters for many solvents have been investigated. For example, the Industrial Solvents Handbook (by Wesley L. Archer) lists the solubility parameters for several solvents. Hansen's solubility parameters are also described in, for example, Color Materials, 77 [4], 188-192 (2004), which also describes the solubility parameters of representative organic solvents.

[0052] From the viewpoints of availability and good solubility of the compound represented by formula (2) and / or the compound represented by formula (3), the second solvent preferably contains an ester. Examples of esters include ester-based solvents such as methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, methyl lactate, ethyl lactate, butyl lactate, 2-methoxy-1-methylethyl acetate (PGMEA), etc. Among these, more preferred esters are ethyl acetate, butyl acetate, ethyl lactate, and 2-methoxy-1-methylethyl acetate (PGMEA).

[0053] The inventors have found that esters have the property of specifically dissolving the impurities represented by formula (2) or (3), and therefore, by using esters, it is possible to efficiently remove impurities in particular. In addition, the use of esters tends to improve the powder properties of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained by recrystallization. It is presumed that the addition of esters also plays a role in adjusting the crystal size of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. When esters are added and refined, the crystal size of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is relatively large, and the powder properties are excellent in fluidity. In other words, the use of esters as the second solvent is highly preferable in terms of reducing impurities in bis(3-amino-4-hydroxyphenyl)hexafluoropropane as well as improving powder properties.

[0054] For reference, the table below shows the SP values, the solubility of the monoamino compound of formula (2) at 23° C., and the solubility of the monoamino mononitro compound of formula (3) at 23° C. for several solvents that can be preferably used as the second solvent and several solvents that do not fall under the category of the second solvent. In the table, "GBL" stands for γ-butyrolactone, "MIBK" stands for methyl isobutyl ketone, and "MTBE" stands for methyl tert-butyl ether.

[0055] [Table 2]

[0056] In the above table, the solubility of the monoamino compound of formula (2) was measured as follows. First, 10 g of the solvent shown in the table above was weighed out and placed in a 50 mL flask made of borosilicate glass equipped with a stirrer and a thermometer. Next, while stirring the solvent with a stirrer, 0.01 g of the monoamino compound of formula (2) was added to the solvent, and the presence or absence of dissolution was confirmed visually. If dissolved, 0.01 g was further added, and the presence or absence of dissolution was similarly confirmed visually. The same operation was repeated until it was visually confirmed that the compound did not dissolve. In the above procedure, the weight at which it was confirmed that the monoamino compound of formula (2) was completely dissolved was measured. The temperature was 23°C.

[0057] The solubility of the monoamino mononitro compound of formula (3) was also measured in the same manner.

[0058] The amount of the second solvent, such as esters, used is, for example, 1 to 50 parts by mass, preferably 3 to 45 parts by mass, more preferably 5 to 40 parts by mass, relative to 100 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities. By using a moderately large amount of the second solvent, the purity of the obtained 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can be further increased, and the grain size of the crystals of the recrystallized 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane can be moderately increased. In addition, by using a not too large amount of the second solvent, layer separation from the first solvent can be suppressed.

[0059] The amount of the second solvent used is not particularly limited, but in order to achieve a balance between sufficient solubility and precipitability, reduction in the amount of impurities, and the like, and to avoid layer separation between the first solvent and the second solvent, the concentration of the second solvent in the solution prepared in the solution preparation step is preferably 0.1 to 7.5 mass%, more preferably 0.5 to 5.0 mass%.

[0060] - Melting of raw materials In the solution preparation step, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities, the first solvent, and the second solvent are usually heated while being stirred. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is completely dissolved. The dissolution is usually performed at 75 to 90°C.

[0061] (Recrystallization process) In the recrystallization step, the temperature of the solution prepared in the solution preparation step is usually lowered to recrystallize 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, and a powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is obtained. By the recrystallization step, the compound represented by formula (2) and / or the compound represented by the following formula (3) are not substantially removed from the crystallization vessel but remain in the solvent side. As a result, a powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with increased purity can be obtained.

[0062] The method for lowering the temperature of the solution in the recrystallization step is not particularly limited, but in order to obtain a powder with good industrial handleability, it is preferable to (i) first slowly lower the temperature to about 70 to 75° C., and then (ii) slowly lower the temperature to about 10 to 30° C., as follows. These will be explained below.

[0063] (i) In the recrystallization step, it is preferable to first slowly lower the temperature of the mixed solution in which the raw materials have been completely dissolved by heating to about 75 to 90°C in the solution preparation step to about 70 to 75°C over 30 minutes to 2 hours to precipitate crystals. In this case, it is preferable to carry out the operation while stirring, since this makes it easier to control the temperature.

[0064] In the above (i), a small amount of "seed crystals" of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane may be added to the mixed solution. When using seed crystals, the amount of addition may be, for example, 0.01 to 0.5 parts by mass relative to 100 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane dissolved in the mixed solution. The seed crystals are not particularly limited as long as they are solid 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. For example, those obtained according to the methods described in Patent Documents 1 to 4 can be used. Commercially available products may also be used.

[0065] (ii) After the above (i), it is preferable to slowly cool the mixed solution to about 10 to 30° C. over about 2 to 8 hours while stirring, which makes it possible to precipitate the fine crystals obtained in (i) while allowing them to grow with a relatively uniform grain size.

[0066] The obtained crystals are preferably collected by filtration under reduced pressure and dried under reduced pressure in an environment of about 20 to 80°C.

[0067] <High purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane> Preferably, the above-mentioned production method can be used to obtain high-purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane.

[0068] That is, preferably, by the above-mentioned production method, it is possible to produce 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having a purity of 99.5% or more as determined by liquid chromatography analysis and a content of the compound represented by the above formula (2) of less than 0.1%. The purity may be 99.5% or more, preferably 99.7% or more, and more preferably 99.9% or more. The purity is ideally 100%, but in reality it is 99.99% or less. The content of the compound represented by formula (2) is ideally 0. Incidentally, the concentration of the compound represented by formula (2) in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in the examples given below is below the detection limit of the measurement.

[0069] Preferably, the above-mentioned production method can be used to produce 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having a purity of 99.5% or more as determined by liquid chromatography analysis and a content of the compound represented by the above formula (3) of less than 0.1%. The purity may be 99.5% or more, preferably 99.7% or more, and more preferably 99.9% or more. The purity is ideally 100%, but in reality it is 99.99% or less. The content of the compound represented by formula (2) is ideally 0. Incidentally, the concentration of the compound represented by formula (3) in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in the examples given below is below the detection limit of the measurement.

[0070] Just to be clear, the above numerical values ​​for "purity determined by liquid chromatography analysis", "content of the compound represented by formula (2)", and "content of the compound represented by formula (3)" are values ​​(Area%) determined from the area of ​​the chart obtained by liquid chromatography analysis.

[0071] The high-purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane powder obtained by the above-mentioned manufacturing method tends to have good industrial handleability, as evaluated in the examples below. Although the details are unclear, it is speculated that such an effect is due to the fact that the powder is prevented from clumping due to the low impurity content.

[0072] The bulk density can be cited as an index characterizing the high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane powder. In this embodiment, the loose bulk density measured using a bulk specific gravity measuring device is preferably 0.31 to 0.49 g / cm. 3 , the bulk density is 0.45~0.64g / cm 3 (however, loose bulk density < hard bulk density).

[0073] <Polymer manufacturing method> The above-mentioned 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having a small amount of impurities is preferably used as a monomer in the production of polymers.

[0074] As an example, a polyamide polymer can be produced by condensation polymerization of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with a small amount of impurities, as described above in the section <High-purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane>, and a dicarboxylic acid or a dicarboxylic acid halide. In other words, an amide bond is formed by reacting an amino group in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane with a carboxy group in a dicarboxylic acid, and the like, to produce a polyamide polymer. The conditions for the polycondensation are not particularly limited, and known polyamide polymer synthesis conditions can be appropriately applied. The polycondensation is usually carried out in an organic solvent capable of dissolving the raw material monomers. A basic catalyst such as pyridine may be used to promote the reaction.

[0075] By using the high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane described above to produce polyamide polymers, it is easy to obtain polyamide polymers with relatively high molecular weights. It is presumed that the low content of the "monofunctional" monoamino compound of formula (2) and monoamino mononitro compound of formula (3) in the monomer raw material before polymerization makes the condensation polymerization reaction "hard to stop," and as a result, a polybenzoxazole precursor with a higher molecular weight can be obtained.

[0076] In addition, polybenzoxazole can be obtained by appropriately selecting the type of dicarboxylic acid or dicarboxylic acid halide in the production of the polyamide polymer and heating the obtained polyamide polymer. The reaction mechanism is that the amide bond portion generated in the production of the polyamide polymer reacts with the hydroxyl group in 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, resulting in the formation of an oxazole ring with the elimination of water.

[0077] Although the embodiments of the present invention have been described above, these are merely examples of the present invention, and various configurations other than those described above can be adopted. Furthermore, the present invention is not limited to the above-described embodiments, and modifications and improvements within the scope of the present invention are included in the present invention. [Industrial Applicability]

[0078] The 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane of the embodiment of the present invention can be used as a raw material for functional polymers such as polyimide, polyamide, polybenzoxazole, etc. The functional polymers have good heat resistance, insulating properties, low dielectric constant, etc., and therefore can be used as insulating materials for various semiconductors. EXAMPLES

[0079] The embodiments of the present invention will be described in detail based on Examples and Comparative Examples. It should be noted that the present invention is not limited to the Examples.

[0080] <Synthesis of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane> (Synthesis Example 1) With reference to the method described in Patent Document 4, 150.0 g (0.35 mol) of 2,2-bis(3-nitro-4-hydroxyphenyl)hexafluoropropane, 0.75 g of FeCl3, and 180 g of isopropanol were placed in a 1000 mL four-neck flask equipped with a thermometer, a Dimroth condenser, a dropping funnel, and a stirrer, and heated with stirring. While maintaining the reaction temperature at 75 to 80° C., 55.0 g (1.1 mol) of hydrazine monohydrate was added dropwise to the flask over 2 hours. After completion of the addition, the mixture was stirred at a reaction temperature of 80° C. for 5 hours. After the reaction was completed, 560 g of ion-exchanged water was added dropwise to the reaction solution over 2 hours. The reaction solution was then slowly cooled to 10°C over 6 hours, and the precipitated crystals were filtered off. The collected crystals were dried in a tray-type vacuum dryer at 80°C to obtain the target product, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (yield: 115 g, yield: 90%, purity: 99.44%). The content of the monoamino compound represented by formula (2) was 0.15%.

[0081] [Physical property data] Monoamino form of formula (2): 2-amino-4-(1,1,1,3,3,3,3-hexafluoro-2-(4-hydroxyphenyl)propan-2-yl)phenol 1 H-NMR(400MHz,(CD3)2SO)δ(ppm):4.65(2H,br-s),6.36(1H,d,J=8.4Hz),6.51(1H,s),6.62(1H,d,J=8.4Hz),6.78(2H,d,J=8.4Hz),7.09(2H,d,J=8.4Hz) 19 F-NMR(400MHz,CD3CN)δ(ppm):-62.9(6F,s)

[0082] (Synthesis Example 2) The same operation as in Synthesis Example 1 was performed except that the dropwise addition temperature of hydrazine monohydrate was set to 50 to 60°C and the reaction temperature was set to 60°C (the reaction conditions were changed to milder conditions than in Synthesis Example 1), to obtain 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (yield: 110 g, yield: 88%, purity: 99.39%). The content of monoamino mononitro compound represented by formula (3) was 0.18%.

[0083] [Physical property data] Monoaminomononitro form of formula (3): 2-amino-4-(1,1,1,3,3,3,3-hexafluoro-2-(4-hydroxy-3-nitrophenyl)propan-2-yl)phenol 1H-NMR(400MHz,(CD3)2SO)δ(ppm):6.35(1H,s),6.52(1H,s),6.66(1H,d,J=8.0Hz),7.19(1H,d,J=8.0Hz),7.45(1H,d,J=8.4Hz),7.79(1H,dJ=8.0) 19 F-NMR(400MHz,CD3CN)δ(ppm):-63.4(6F,s)

[0084] <Production of high-purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane> Example 1 In a 500 mL four-neck flask equipped with a thermometer, a Dimroth condenser, and a stirrer, 50.0 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Synthesis Example 1, 55 g of IPA (isopropanol), 190 g of ion-exchanged water, and 12.5 g of PGMEA (propylene glycol monomethyl ether acetate) as an added ester were placed, and the mixture was heated to a liquid temperature of 80° C. while stirring to dissolve the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. Here, isopropanol and ion-exchanged water are the first solvent, and PGMEA is the second solvent. At this time, no layer separation was observed in the liquid in the flask.

[0085] After dissolving the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, the liquid temperature was lowered to 75°C over 1 hour to precipitate crystals. The liquid temperature was then slowly cooled to 10°C over 4 hours, and the precipitated crystals were filtered off. The collected crystals were dried in a tray-type vacuum dryer at 80°C. As a result, purified 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained.

[0086] Example 2 The same operation as in Example 1 was carried out except that 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Synthesis Example 2 was used in Example 1. Then, purified 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained. Just to be clear, in Example 2, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0087] Example 3 The same procedure as in Example 1 was carried out except that 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane (purity 99.60%, content of monoamino mononitro compound of formula (3) 0.16%) manufactured by Tokyo Chemical Industry Co., Ltd. was used as the raw material. Then, purified 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained. Just to be clear, in Example 3, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0088] Example 4 Except for using 12.5 g of ethyl lactate instead of PGMEA as the second solvent, the same operation as in Example 1 was carried out. Thus, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained. Just to be clear, in Example 4, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0089] Example 5 Except for using 12.5 g of ethyl acetate instead of PGMEA as the second solvent, the same operation as in Example 1 was carried out. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained. Just to be clear, in Example 5, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0090] Example 6 Except for using 12.5 g of butyl acetate instead of PGMEA as the second solvent, the same procedure as in Example 1 was carried out. Thus, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane represented by formula (1) was obtained. Just to be clear, in Example 6, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0091] Example 7 The same operation as in Example 1 was carried out except that the second solvent was 12.5 g of γ-butyrolactone (GBL) instead of PGMEA. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained. Just to be clear, in Example 7, as in Example 1, no layer separation was observed in the liquid in the flask when 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved.

[0092] Comparative Example 1 The purification procedure was carried out in the same manner as in Example 1, except that no second solvent, PGMEA, was used at all. Thus, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained.

[0093] Comparative Example 2 The same operations as in Example 1 were carried out except that 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Synthesis Example 2 was used instead of Synthesis Example 1, and the purification operation was carried out without using any PGMEA as the second solvent. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane of formula (1) was obtained.

[0094] Comparative Example 3 The same operation as in Example 1 was carried out except that the amount of the second solvent, PGMEA, was increased to 27.5 g. However, although 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was dissolved, the mixed solution in the flask was separated into two layers. 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained from this mixed solution by a crystallization operation.

[0095] Comparative Example 4 The same procedure as in Example 1 was carried out except that 12.5 g of toluene was added instead of PGMEA as the second solvent, and the purification procedure was carried out. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained.

[0096] Comparative Example 5 The same operation as in Example 1 was carried out except that 12.5 g of methyl tert-butyl methyl ether was added instead of PGMEA as the second solvent, and the purification operation was carried out. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained.

[0097] Comparative Example 6 The same operation as in Example 1 was carried out except that 12.5 g of methyl isobutyl ketone was added instead of PGMEA as the second solvent and purification was carried out. Then, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was obtained.

[0098] <Evaluation> (purity / impurity amount) The purity, monoamino content, and monoamino mononitro content of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained by recrystallization in each of the Examples and Comparative Examples were measured using liquid chromatography under the following specific conditions. Equipment: LC1100 (Agilent) Column: SunShell-C18, 2.6 μm, 100 mm × 4.6 mm I,D (ChromaNic-Technologies). Mobile phase: Acetonitrile / 10mM formic acid in water Gradient: 25 / 75 (0-10 min) → 45 / 75 (15-40 min) → 25 / 75 (41-45 min)

[0099] (Handling: Fluidity evaluation (Rototest)) 60 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in each Example or Comparative Example was poured into the opening of a funnel with a funnel aperture of 150 mm, nozzle diameter of 12 mm, and nozzle length of 22 mm. Then, it was confirmed whether the powder was discharged naturally. When the entire amount of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was discharged naturally, it was evaluated as ◯ (good), and when it was not discharged naturally, it was evaluated as × (bad).

[0100] (Handling: Measurement of angle of repose) A funnel with a funnel mouth diameter of 150 mm, nozzle diameter of 12 mm, and nozzle length of 22 mm was used, and a sieve plate with 0.5 mm openings was placed on the funnel and a horizontal stand was placed 4.5 cm below the tip of the funnel nozzle. Next, 30 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in each Example or Comparative Example was placed on a sieve plate, and the powder was dropped toward the funnel nozzle using a brush and deposited on a horizontal table. Thereafter, a photograph was taken of the pile of accumulated powder, and the angle of repose was measured on the photograph. The smaller the angle of repose, the more easily the powder flows and the easier it is to handle.

[0101] (Handling: Measurement of bulk density (loose, hard)) The bulk density was measured using a JIS bulk specific gravity measuring instrument manufactured by Tsutsui Rikagaku Kikai Co., Ltd. The bulk specific gravity measuring instrument is equipped with a funnel with a funnel mouth diameter of 150 mm, a nozzle diameter of 12 mm, and a nozzle length of 22 mm, a sieve plate with a mesh size of 0.5 mm on the funnel, and a cylindrical 30 mL receiver at the bottom of the funnel nozzle. 30 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in each Example or Comparative Example was placed on the sieve plate of the measuring device, and slowly dropped into the receiver using a brush. This allowed the receiver to be naturally filled with 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane. Then, the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane powder overflowing from the receiver was rubbed off. After that, the weight of the receiver was measured to calculate the loose bulk density. In addition, when the powder was dropped into the receiver, the lower part of the receiver was lightly struck while being compressed and filled, and the packed bulk density was calculated from the weight obtained.

[0102] (Handling: Solvent solubility) The solubility in a solvent of the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in each of the Examples and Comparative Examples was evaluated by the following procedure. 5 g of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane powder was placed in a 100 mL flask made of borosilicate glass equipped with a stirrer and a thermometer. While stirring the powder in the flask at a constant speed, 50 g of γ-butyrolactone (GBL) was quickly poured into the flask. After that, the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane was completely dissolved at 20 to 25°C while maintaining the constant stirring speed. In the above procedure, the time taken for 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to completely dissolve was measured immediately after the addition of GBL.

[0103] The above information is summarized in Tables 3 and 4.

[0104] [Table 3]

[0105] [Table 4]

[0106] As shown in Table 3, particularly in the column "Results of recrystallization," (i) first, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities is dissolved in a solvent containing the first solvent and the second solvent to obtain a homogeneous solution, and (ii) 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane is then recovered by recrystallization. Through these procedures, 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having an extremely low content of the monoamino compound of formula (2) or the monoamino mononitro compound of formula (3) could be produced. In addition, as shown in Table 4, the powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in the examples had good handleability.

[0107] On the other hand, in Comparative Examples 1 and 2 in which no second solvent was used, the amount of the monoamino compound represented by formula (2) or the monoamino mononitro compound represented by formula (3) could not be sufficiently reduced. The same was true in Comparative Examples 4 to 6 in which a solvent having a low solubility for the monoamino compound represented by formula (2) or a solvent having a low solubility for the monoamino mononitro compound represented by formula (3) was used as the second solvent. Also, in Comparative Example 3, in which the amount of the second solvent used was too large and the second solvent was separated into layers from the first solvent, the amount of the monoamino mononitro compound represented by formula (3) could not be sufficiently reduced.

[0108] <Additional Evaluation> (Polymer synthesis example 1) The high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Example 1 and 4,4'-oxybis(benzoyl chloride) were polycondensed in a molar ratio of 1:1 in N-methylpyrrolidone solvent using pyridine as a catalyst at a temperature adjusted to 4 to 25° C. As a result, a solution of a polybenzoxazole precursor (polyamide polymer) was obtained.

[0109] (Polymer synthesis example 2 (comparison)) A solution of a polybenzoxazole precursor (polyamide polymer) was obtained in the same manner as in Polymer Synthesis Example 1, except that the "high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Example 1" was changed to the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Comparative Example 1.

[0110] (Polymer synthesis example 3 (comparison)) A solution of a polybenzoxazole precursor (polyamide polymer) was obtained in the same manner as in Polymer Synthesis Example 1, except that the "high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Example 1" was changed to the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Comparative Example 2.

[0111] The weight average molecular weight Mw and the polydispersity Mw / Mn of each of the polybenzoxazole precursors obtained in the above Polymer Synthesis Examples 1 to 3 were determined by GPC measurement using polystyrene as the standard substance.

[0112] In addition, the solutions of the polybenzoxazole precursors obtained in the above Polymer Synthesis Examples 1 to 3 were applied onto a glass substrate using a spin coater, and then the temperature was increased stepwise and continuously heated at 130° C. for 30 minutes, at 200° C. for 1 hour, and at 300° C. for 2 hours to obtain a polybenzoxazole film on the glass substrate. At this time, the application conditions were appropriately adjusted so that the film thickness was 20 to 25 μm. The light transmittance T365 at a wavelength of 365 nm, the light transmittance T400 at a wavelength of 400 nm, YI (yellow index, defined by ASTM D1925), and total light transmittance TT of the obtained film were measured.

[0113] The above information is summarized in Table 5.

[0114] [Table 5]

[0115] As shown in Table 5, a polybenzoxazole precursor having a higher molecular weight could be obtained by using the high-purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Example 1. Since the monomer raw material before polymerization did not substantially contain the "monofunctional" monoamino compound of formula (2) or monoamino mononitro compound of formula (3), the condensation polymerization reaction was unlikely to be interrupted, and as a result, it is believed that a polybenzoxazole precursor having a higher molecular weight could be obtained. Furthermore, by using the high purity 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane obtained in Example 1, polybenzoxazole with good light transmittance and little coloring (yellowing) could be obtained.

Claims

1. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, comprising purifying impurity-containing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane to produce 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane having an increased purity, comprising the steps of: The manufacturing method includes: A solution preparation step of preparing a homogeneous solution in which 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities is dissolved in a solvent; a recrystallization step of recrystallizing the 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane dissolved in the solution to obtain a powder of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane; Including, The method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, wherein the solvent contains at least the following first solvent and second solvent: First solvent: a solvent in which the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 23° C. is 0.05 to 3.0 g [g / 10 g] and the solubility of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane at 80° C. is 0.2 to 6.0 g [g / 10 g]. Second solvent: a solvent in which the solubility at 23° C. of a compound represented by the following formula (2) is 2.6 [g / 10 g] or more, and / or the solubility at 23° C. of a compound represented by the following formula (3) is 2.2 [g / 10 g] or more. 【Chemistry 1】

2. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane according to claim 1, The SP value of the second solvent is 8.0 to 13.0 [(cal / cm ３ ) ０．５ The present invention relates to a method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane,

3. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane according to claim 1 or 2, The method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, wherein the second solvent contains an ester.

4. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane according to any one of claims 1 to 3, The amount of the second solvent in the solution prepared in the solution preparation step is 1 to 50 parts by mass per 100 parts by mass of 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane containing impurities.

5. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane according to any one of claims 1 to 4, comprising the steps of: A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, wherein the concentration of the second solvent in the solution prepared in the solution preparation step is 0.1 to 7.5 mass %.

6. A method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane according to any one of claims 1 to 5, The method for producing 2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane, wherein the first solvent is a mixed solvent of water and an alcohol.

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