Crystallization of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane and method for producing the same

Abstract

Provided is a 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane that is suitable for industrial production. As a solution to this problem, a crystal of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane is provided.

Description

Technical Field

[0001] This invention relates to the crystallization of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane and its manufacturing method. Background Technology

[0002] Tetraphenol compounds can be used as raw materials for epoxy resins used in packaging materials, laminating materials, and electrical insulating materials for integrated circuits; as curing agents for epoxy resins; as color developers or anti-fading agents for thermal recording; and as raw materials for electronic materials or photosensitive materials. In addition, they are also widely used as additives and inclusion compounds such as antioxidants, bactericides, and antibacterial and antifungal agents.

[0003] As a method for manufacturing tetraphenol compounds, for example, Patent Document 1 details a method for dehydrating and condensing phenols with 2,2-bis(4-carbonylcyclohexane)propane (hereinafter sometimes referred to as "4HBPA") in the presence of hydrogen chloride gas using 3-mercaptopropionic acid as a cocatalyst.

[0004] On the other hand, 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane (hereinafter sometimes referred to as "Compound A"), which is a tetraphenol compound, has an experimental example of its manufacture reported in Patent Document 2.

[0005] Patent documents Patent Document 1: Japanese Patent Application Publication No. 49-000250 Patent Document 2: Japanese Patent Application Publication No. 06-107769 Summary of the Invention Patent Document 2 describes the reaction of 49.1 g of 4HBPA to obtain 230.0 g of compound A. However, based on the amount of 4HBPA used (molecular weight 236.18), the obtained amount is excessive compared to the theoretical yield of 143.1 g of compound A (molecular weight 688.45). Therefore, it is speculated that the compound A obtained as described in Patent Document 2 may contain a large amount of solvent or matrix (2,6-xylenol). Furthermore, when the inventors prepared compound A based on the description in Patent Document 2 and under the same reaction conditions and procedures, as described in Comparative Example 1 below, they found that the yield of compound A was extremely low.

[0006] From the above, it is clear that the compound A described in Patent Document 2 was obtained by filtering as a precipitate, but its purity was extremely low and it contained a large amount of solvent or matrix, so it is difficult to say that it was a compound A suitable for industrial production.

[0007] The present invention was made against the background described above, and its objective is to provide a single-isolated form of compound A suitable for industrial production.

[0008] The inventors conducted in-depth research on the method of isolating compound A, and for the first time discovered that compound A could be isolated in crystalline form, thus completing this invention.

[0009] The present invention is as follows.

[0010] 1. A crystal, characterized in that it is a crystallization of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane.

[0011] 2. The crystallization according to 1. is characterized in that the onset temperature of the endothermic peak obtained by differential scanning calorimetry is in the range of 277~289℃.

[0012] 3. The crystallization according to 1. is characterized in that, in the powder X-ray diffraction peak pattern obtained by Cu-Kα rays, there are diffraction peaks at diffraction angles 2θ of 15.2±0.2°, 17.5±0.2°, 18.3±0.2° and 21.9±0.2°.

[0013] 4. A method for producing crystals according to any one of 1. to 3., characterized in that it comprises the following steps: a reaction to generate 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane in a mixture containing 4 to 30 moles of 2,6-xylenol relative to 1 mole of 2,2-bis(4-carbonylcyclohexyl)propane and an acid catalyst, thereby crystallizing the precipitate.

[0014] The crystallization of compound A of the present invention is suitable for industrial production due to its good operability, and can yield compound A with high efficiency and high purity. In addition, due to its high bulk density, a large amount of compound A can be filled into a container of a certain volume, resulting in excellent transportation efficiency, storage efficiency and reaction efficiency.

[0015] The method for producing the crystallization of compound A of the present invention can isolate compound A in a crystalline form with good operability and high packing density. In addition, it can be implemented industrially and is a highly efficient manufacturing process that can produce compound A with high purity. Attached Figure Description

[0016] Figure 1 This is a graph showing the differential scanning calorimetry (DSC) data of the crystallization of compound A obtained in Example 1.

[0017] Figure 2This is a graph showing the powder X-ray diffraction (PXRD) determination of the crystals of compound A obtained in Example 1. Detailed Implementation

[0018] The present invention will now be described in detail.

[0019] The crystallization method of the present invention includes the following steps: a reaction to generate 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane is carried out in a mixture containing 4 to 30 moles of 2,6-xylenol relative to 1 mole of 2,2-bis(4-carbonylcyclohexyl)propane and an acid catalyst, and a reaction crystallization step is carried out to precipitate the 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane.

[0020] The 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane (compound A) involved in this invention has the following chemical structure.

[0021] [Chemistry 1]

[0022] <Reactive Crystallization Process> In the crystallization method of the present invention, compound A is generated by a dehydration condensation reaction of 4 equivalents of 2,6-xylenol and 1 equivalent of 4HBPA (2,2-bis(4-carbonylcyclohexane)propane), together with 2 equivalents of water.

[0023] [Chemistry 2]

[0024] The content of 2,6-xylenol in the mixture of the crystallization method of the present invention is preferably in the range of 5 to 25 moles relative to 1 mole of 4HBPA, more preferably in the range of 6 to 22 moles, and particularly preferably in the range of 8 to 20 moles.

[0025] If the amount of 2,6-xylenol used is less than 4 moles, the reaction will slow down, and more byproducts such as polynuclear bodies obtained by further condensation of 4HBPA or 2,6-xylenol will be produced, in addition to the target compound A. Therefore, this is not preferred. Furthermore, if the amount of 2,6-xylenol used exceeds 30 moles, although the reaction rate is increased, the recovery of unreacted 2,6-xylenol increases, reducing productivity. In addition, crystallization will be slower, or the amount of compound A generated by the reaction may not reach the saturation solubility of the mixture, thus preventing crystallization. Therefore, this is also not preferred.

[0026] The reaction temperature for generating compound A and the temperature at which crystallization occurs are preferably in the range of 20 to 100°C, and more preferably in the range of 30 to 80°C.

[0027] The reaction pressure for the formation of compound A and the pressure for crystallization are usually carried out at atmospheric pressure, but can also be carried out under pressure or reduced pressure depending on the boiling point of the organic solvent used, so that the reaction temperature is within the aforementioned range. Furthermore, when hydrogen chloride gas is used as an acid catalyst, it can also be carried out under pressure.

[0028] The mixing method for the mixture, raw materials, etc., used in the manufacturing method of the present invention is not particularly limited. Examples include a method in which the total amount of raw materials, etc., used are added to the reaction vessel at once for mixing; or a method in which a mixture containing a portion of the 2,6-xylenol used and an acid catalyst, and, if necessary, a co-catalyst or reaction solvent, is mixed to form a mixture containing the remaining amount of 4HBPA and 2,6-xylenol, and, if necessary, further containing a reaction solvent. The latter mixing method is preferred from the perspective of reaction selectivity or from the perspective of being able to adjust the precipitation rate of the crystals during the reaction. In the case of this mixing method, the mixing is carried out in a manner that takes 0.5 to 5 hours, preferably in a manner that the amount of raw materials used after mixing is sufficient.

[0029] The reaction time for generating compound A varies depending on the amount of catalyst and the reaction temperature, and is usually in the range of 3 to 48 hours, preferably within the range of 3 to 24 hours.

[0030] The endpoint of the reaction that produces compound A can be confirmed by liquid chromatography or gas chromatography. Preferably, the endpoint is defined as the time point at which unreacted 4HBPA disappears or the increase in compound A, the target analyte, is no longer confirmed.

[0031] (Acid catalyst) The acid catalyst used in the crystallization method of this invention can be any type of inorganic or organic acid. Examples of inorganic acids include hydrogen chloride gas, hydrochloric acid, sulfuric acid, phosphoric acid, and sulfuric anhydride. Examples of organic acids include aromatic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid, alkane sulfonic acids with 1 to 4 carbon atoms such as methanesulfonic acid and ethanesulfonic acid, and trifluoromethanesulfonic acid and trichloroacetic acid. In addition, metal halides such as aluminum chloride and ferric chloride, or solid acids such as cation exchange resins, can also be used as acid catalysts.

[0032] Among these, inorganic acids are preferred. Among inorganic acids, hydrochloric acid is more preferred. The amount of this inorganic acid used is preferably in the range of 3 to 18 moles relative to 1 mole of 4HBPA, more preferably in the range of 5 to 15 moles, and even more preferably in the range of 5 to 12 moles.

[0033] (co-catalyst) In the crystallization method of the present invention, a thiol compound may be used as a co-catalyst in combination with an acid catalyst as needed.

[0034] As for the thiol compound, there are no particular limitations as long as it is a compound containing a thiol group and does not adversely affect the reaction selectivity. Examples of such compounds include: carboxylic acids containing thiol groups such as 3-mercaptopropionic acid and mercaptoacetic acid; alkyl thiols with 1 to 12 carbon atoms such as methanethiol, 1-octylthiol, and 1-dodecanethiol; and thiol alcohols such as mercaptoethanol and mercaptobutanol. Among these, alkyl thiols with 1 to 12 carbon atoms, such as 1-octylthiol, are preferred. Furthermore, it can also be used in the form of an aqueous solution of the sodium salt.

[0035] The preferred amount of thiol compound used is in the range of 0.01 to 0.5 moles relative to 1 mole of 4HBPA. If the amount is less than 0.01 moles, its function as a co-catalyst cannot be fully realized, and even if the amount exceeds 0.5 moles, its function as a co-catalyst cannot be further realized, and the selectivity hardly changes.

[0036] (Reaction solvent) In the crystallization method of the present invention, a reaction solvent is not required if operability is not an issue. However, a reaction solvent may be used to improve operability in industrial production. The reaction solvent used affects the ease of crystallization of compound A depending on its solubility; therefore, it is preferable to select one appropriately based on its solubility. Furthermore, it is preferable that the reaction solvent does not distill off the reaction vessel at the reaction temperature and is inactive for the reaction. Examples of usable solvents include aromatic hydrocarbons such as toluene, xylene, and benzene. The amount of this solvent used is in the range of 0.1 to 5 times by weight relative to 2,6-xylenol, preferably in the range of 0.1 to 3 times by weight, and more preferably in the range of 0.1 to 2 times by weight.

[0037] The mixture in the crystallization method of the present invention may contain water. Besides water generated from the dehydration condensation reaction of 2,6-xylenol and 4HBPA, examples include water contained in acid catalysts such as hydrochloric acid or phosphoric acid, or water added as a solvent. The water in the mixture may dissolve in 2,6-xylenol to form a homogeneous layer, or the presence of water may exceed its solubility, resulting in layer separation. However, in either case, as long as the reaction can proceed and does not hinder crystallization, a higher amount of water is acceptable. The amount of water contained in the mixture in the crystallization method of the present invention is preferably 5 times or less by weight relative to the 4HBPA used.

[0038] Furthermore, by conducting the reaction under dehydration conditions that remove water from the reaction system, such as water generated in the reaction or water contained in the acid catalyst used, the reaction can proceed more quickly compared to the case without dehydration, the formation of byproducts is suppressed, and the target product can be obtained in a higher yield, which is therefore preferred. There are no particular limitations on the dehydration method; examples include dehydration by adding a dehydrating agent, dehydration by reducing pressure, and dehydration by azeotropic reaction with a solvent under normal or reduced pressure. There are no particular limitations on the dehydrating agents that can be added as needed. Examples include: organic dehydrating agents with orthoester skeletons such as trimethyl orthoformate, triethyl orthoformate, trimethyl orthoacetate, triethyl orthopropionate, trimethyl orthobutyrate, trimethyl orthoisobutyrate, and 1,1,1-trimethoxyoctane; zeolite-type dehydrating agents such as molecular sieves (3A) and molecular sieves (4A); and inorganic anhydrous salts that may contain water of crystallization, such as calcium chloride (anhydrous), calcium sulfate (anhydrous), magnesium chloride (anhydrous), magnesium sulfate (anhydrous), potassium carbonate (anhydrous), potassium sulfide (anhydrous), potassium sulfite (anhydrous), sodium sulfate (anhydrous), sodium sulfite (anhydrous), and copper sulfate (anhydrous).

[0039] In the manufacturing method of the present invention, seed crystals may not be used during crystallization. When seed crystals are used, there are no restrictions on the type of crystal that can be used as a seed crystal; however, it is preferable to use crystals of compound A of the present invention that have been pre-manufactured by performing the manufacturing method of the present invention in a seedless state. The amount of seed crystal used is preferably in the range of 0.1 to 1.0% by weight relative to compound A generated by the reaction.

[0040] <Post-reaction crystallization process treatment> (Treatment before crystallization) For reaction-end mixtures containing crystals precipitated by the crystallization method of the present invention, the following treatments are preferably performed, for example: mixing an alkaline aqueous solution such as sodium hydroxide solution to neutralize the acid catalyst used in the reaction; or removing the separated aqueous layer, or washing the oil layer containing crystals with water as needed; or post-treatment by removing the solvent or excess 2,6-xylenol used in the reaction by distillation.

[0041] Crystals can be isolated from the reaction mixture containing the precipitated crystals, for example, through filtration.

[0042] (Treatment after isolating crystals) The isolated crystals are preferably washed with water or an organic solvent. Aromatic hydrocarbon solvents are preferred as the organic solvent used. The amount of this organic solvent used relative to the crystallization of compound A is preferably 0.5 to 5 times by weight, more preferably 0.5 to 2.5 times by weight, even more preferably 0.5 to 2 times by weight, and particularly preferably 0.5 to 1.5 times by weight.

[0043] The resulting crystals can be dried to remove the solvent used. Drying is preferably carried out at a temperature in the range of 20–160°C, more preferably in the range of 100–150°C, and even more preferably in the range of 110–145°C. Drying can be carried out under normal pressure or reduced pressure, but in industrial applications, a reduced pressure of around 10 kPa is preferred, more preferably around 5 kPa, and even more preferably around 1.5 kPa, as this reduced pressure allows for more efficient removal of the solvent used, and is therefore preferred.

[0044] <Crystallization of Compound A of the Invention> The crystallization of compound A in this invention is preferably characterized by having an endothermic peak starting temperature of 277-289°C as obtained by differential scanning calorimetry, or having diffraction peaks at diffraction angles 2θ of 15.2±0.2°, 17.5±0.2°, 18.3±0.2°, and 21.9±0.2° in the powder X-ray diffraction peak pattern obtained by Cu-Kα rays, and either or both of the above-mentioned endothermic peak starting temperature and powder X-ray diffraction peak pattern.

[0045] That is, the crystals of compound A of the present invention preferably have any one of the following morphologies (i) to (iii): (i) the onset temperature of the endothermic peak obtained by differential scanning calorimetry is in the range of 277 to 289 °C; (ii) in the powder X-ray diffraction pattern obtained by Cu-Kα rays, diffraction peaks are present at diffraction angles 2θ of 15.2 ± 0.2°, 17.5 ± 0.2°, 18.3 ± 0.2°, and 21.9 ± 0.2°; (iii) the onset temperature of the endothermic peak obtained by differential scanning calorimetry is in the range of 277 to 289 °C, and in the powder X-ray diffraction pattern obtained by Cu-Kα rays, diffraction peaks are present at diffraction angles 2θ of 15.2 ± 0.2°, 17.5 ± 0.2°, 18.3 ± 0.2°, and 21.9 ± 0.2°. Of these, morphology (iii) is more preferred.

[0046] The onset temperature of the endothermic peak obtained by differential scanning calorimetry for the crystallization of the present invention is more preferably in the range of 279~287°C, further preferably in the range of 280~286°C, and particularly preferably in the range of 281~285°C.

[0047] In the powder X-ray diffraction peak pattern obtained by Cu-Kα rays, the present invention further exhibits diffraction peaks at diffraction angles 2θ at 14.7±0.2°, 19.3±0.2°, and 19.6±0.2°, in addition to the peaks mentioned above.

[0048] Furthermore, based on the peak with the highest intensity, the relative intensity of the powder X-ray diffraction peak obtained from Cu-Kα rays is preferably 10 or more, more preferably 25 or more. However, depending on the measuring apparatus or conditions, the relative intensity may vary in the case of a mixture with other crystals. Therefore, the crystalline phase can be identified based on the analytical methods of conventional powder X-ray diffraction analysis.

[0049] The purity of the crystallized compound A, in high-performance liquid chromatography (HPLC) analysis, is such that the peak area of ​​compound A is preferably 90.0% or more, more preferably 93.0% or more, and even more preferably 96.0% or more, relative to the peak area of ​​all components detected at a wavelength of 280 nm. Furthermore, the HPLC analysis method for the purity of the crystals of the present invention is based on the HPLC analysis (composition) method in the analytical methods of the embodiments described later.

[0050] Because the compound A of the present invention is a crystalline solid with a sufficiently high bulk density, it is excellent and useful in terms of operability. The loose bulk density of the crystals of compound A of the present invention is preferably 0.2 g / cm³. 3 Above 0.45g / cm 3 The following range is more preferably 0.2 g / cm³. 3 Above 0.4g / cm 3 The following range is further preferably 0.25 g / cm³. 3 Above 0.4g / cm 3 The following range is particularly preferred: 0.25 g / cm³ 3 Above 0.35g / cm 3 The following range.

[0051] The content of 2,6-xylenol in the crystals of compound A of the present invention is preferably 5% by weight or less, more preferably 3% by weight or less, even more preferably 2% by weight or less, and particularly preferably 1% by weight or less. Furthermore, the analysis of the content of 2,6-xylenol in the crystals of the present invention can be performed using the HPLC analysis (quantitative) method described in the analytical methods of the embodiments described later.

[0052] Example The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments.

[0053] <Analytical Methods> 1. High-performance liquid chromatography (HPLC) analysis (1) Determination of the purity of compound A crystallization and the selectivity of compound A in the reaction solution (composition) The purity of compound A crystallization is the percentage of the peak area of ​​compound A relative to the peak areas of all components detected at a wavelength of 280 nm.

[0054] The selectivity of compound A in the reaction solution is calculated using the following formula.

[0055] [Calculation formula] (Selectivity) = (Peak area ratio of compound A) ÷ {100 - (Peak area ratio of 2,6-xylenol)} × 100 (method) Collect a specified amount of sample into a 50 mL volumetric flask, mix with methanol until the mark is reached to prepare a sample solution, and analyze it using the following apparatus and conditions.

[0056] (Sample quantity) Reaction solution: 85~110 mg / 50 mL methanol; Crystallization solution: 40~50 mg / 50 mL methanol (Apparatus and conditions) Apparatus: Shimadzu HPLC LC-2030 / manufactured by Shimadzu Corporation Chromatographic column: Shim-Pack CLC-ODS, 6mm×15cm / manufactured by Shimadzu GLC Corporation Column oven temperature: 50℃ Flow rate: 1.0 mL / min. Mobile phase: (A) 0.2 vol% aqueous acetic acid solution, (B) methanol Gradient conditions: Mobile phase (B) volume % (from the start of analysis) 50% (0 min.) → 100% (30 min.) → 100% (45 min.) Sample injection volume: 20 μL Detection wavelength: 280nm (2) Analysis of the solvent content in crystallization (quantitative) (method) The contents of toluene and 2,6-xylenol in the crystals were quantified by the absolute calibration curve method.

[0057] Collect 100 mg of crystals into a 50 mL volumetric flask and mix with methanol until the mark is reached to prepare a sample solution. For the detection wavelength, 2,6-xylenol is 280 nm and toluene is 254 nm. Otherwise, the sample solution is analyzed using the same apparatus and conditions as described in (1) above.

[0058] 2. Differential Scanning Calorimetry (DSC) (Analysis Methods) Collect 2-3 mg of crystals into an aluminum sample container, cap it, and pressurize it to prepare the sample. The resulting sample is analyzed using the following apparatus and conditions.

[0059] (Apparatus and conditions) Device: DSC7020 / Hitachi High Technology Manufacturing Co., Ltd. Heating rate: 10℃ / min. Measurement temperature range: 30~350℃ Measurement atmosphere: Nitrogen gas 50 mL / min. 3. Powder X-ray Diffraction (PXRD) Analysis After thoroughly grinding the crystals in a mortar, they were filled into the measuring box. The resulting sample was analyzed using the following apparatus and conditions.

[0060] (Measurement conditions) Device: MiniFlex600-C / manufactured by Rigaku Co., Ltd. X-ray source: CuKα Scan axis: 2θ / θ Mode: Continuous Measurement range: 2θ = 5°~90° Step size: 0.02° Speed ​​measurement time: 10° / min. Entrance slit: 0.25° Receiving slit: 13.00mm Tube voltage: 40kV Tube current: 15mA 4. Determination of the bulk density of crystals (Measurement Method) The bulk density is calculated by dividing the weight of the crystals filled into the graduated cylinder by the volume measured immediately after the crystals are filled into the graduated cylinder.

[0061] The value of the tapped bulk density is calculated by dividing the weight of the crystals filled in the graduated cylinder by the volume measured after manually vibrating the graduated cylinder 300 times.

[0062] <Comparative Example 1> 165.3 g of 2,6-xylenol was added to a 1 L four-necked flask equipped with a thermometer, stirrer, and condenser, and the flask was purged with nitrogen. Next, 1.4 g of 3-mercaptopropionic acid and 68.9 g of concentrated hydrochloric acid were added, and the flask was heated to 61 °C. Then, 16.7 g of 4 HBPA was added in a single batch, and the mixture was stirred at 59–61 °C to allow the reaction to proceed.

[0063] Within 1.5 hours of the reaction starting, the selectivity of compound A was 30%, and no crystallization was observed.

[0064] <Example 1> 165.3 g of 2,6-xylenol was added to a 1 L four-necked flask equipped with a thermometer, stirrer, and condenser, and the flask was purged with nitrogen. Next, 1.4 g of 3-mercaptopropionic acid and 68.9 g of concentrated hydrochloric acid were added, and the mixture was heated to 61 °C. Then, 16.7 g of 4 HBPA was added in a single batch, and the mixture was stirred at 59–61 °C for 22 hours to allow the reaction to proceed. The selectivity was 50% for the first 3 hours of the reaction, with no crystal formation observed. However, the selectivity was 85% for the first 22 hours, and crystal formation was observed.

[0065] The reaction solution was neutralized by mixing 75% phosphoric acid (0.3g), 16% sodium hydroxide aqueous solution (172.1g), and concentrated hydrochloric acid (10.2g). The solution was heated to 88°C to separate the crystallized oil layer from the water layer, and the water layer (232.3g) was removed. For the resulting slurry containing the crystallized oil layer, toluene (142.7g) was added dropwise over 1.5 hours while maintaining the temperature between 87 and 96°C. Heating was stopped after the addition was complete, and the slurry was cooled to room temperature. After 18 hours of initial cooling, the slurry was centrifuged and filtered to remove the crystals.

[0066] The filtered crystals were washed sequentially with water (46.2 g) and toluene (45.1 g). The crystals were heated under reduced pressure at 30 °C for 1 hour, then heated from 30 °C to 140 °C over 45 minutes, and finally dried at 140 °C for 1 hour to obtain dried crystals of compound A (33.3 g, yield 68 mol% (relative to 4 HBPA moles)).

[0067] The formation of compound A, a deprotonated molecule with a molecular weight of 687.44, was confirmed by LC / MS (ESI).

[0068] The purity of the crystalline compound A, as determined by HPLC analysis, was 96%. Furthermore, the crystals contained 2,6-xylenol (1.4 wt%) and toluene (0.1 wt%).

[0069] The DSC and PXRD analyses of the obtained crystals were performed using the methods described above. The analytical graphs are shown below. Figure 1 and 2 .

[0070] In DSC analysis, an endothermic peak (283℃: peak onset temperature) consistent with the melting of crystals was clearly observed.

[0071] Since the diffraction pattern was also observed in the PXRD analysis, it was confirmed to be crystallization. The diffraction angles 2θ (°) of the diffraction peaks and the peaks with a relative intensity of 25 or higher relative to the most intense peak are shown in Table 1.

[0072] [Table 1]

[0073] Furthermore, when the bulk density of the obtained crystals was measured, the loose bulk density was 0.30 g / cm³. 3 The tapped bulk density is 0.45 g / cm³. 3 .

[0074] Because the crystals of the present invention obtained in the examples contain a low amount of solvent, the solvent exposure of compound A during storage, transportation, and manufacture of resins or derivatives using it can be reduced, thus contributing to the health of operators and environmental protection. Furthermore, the bulk density measurement results clearly show that the loose bulk density is 0.30 g / cm³. 3 The above features offer significant advantages in industrial manufacturing, making operation easy and enabling the efficient production of compound A.

Claims

1. A crystal, characterized in that, It is a crystal of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane.

2. The crystallization according to claim 1, characterized in that, The onset temperature of the endothermic peak obtained by differential scanning calorimetry is in the range of 277~289℃.

3. The crystallization according to claim 1, characterized in that, In the powder X-ray diffraction peak pattern obtained by Cu-Kα rays, diffraction peaks are present at diffraction angles 2θ of 15.2±0.2°, 17.5±0.2°, 18.3±0.2° and 21.9±0.2°.

4. A method for producing crystals according to any one of claims 1 to 3, characterized in that, The process includes the following steps: a reaction to generate 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane is carried out in a mixture containing 4 to 30 moles of 2,6-xylenol relative to 1 mole of 2,2-bis(4-carbonylcyclohexyl)propane and an acid catalyst, and a reaction crystallization step is carried out to crystallize the precipitate.

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