Crystals of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl) propane and production method for same

Abstract

The present invention addresses the problem of providing an isolate of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl) propane in a form that is suited to industrial production. Provided are crystals of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl) propane.

Description

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

[0001] The present invention relates to crystals of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane and a method for producing the same.

[0002] Tetrakisphenol compounds are useful as raw materials for epoxy resins used in sealing materials, laminate materials, and electrical insulating materials for integrated circuits, curing agents for epoxy resins, color developers and anti-fading agents used in thermal recording, raw materials for electronic materials and photosensitive materials, and are also widely used as additives for antioxidants, disinfectants, antibacterial and antifungal agents, and clathrate compounds. As a method for producing tetrakisphenol compounds, for example, Patent Document 1 specifically describes a method in which a phenol and 2,2-bis(4-oxycyclohexyl)propane (hereinafter sometimes referred to as "4HBPA") are reacted by dehydration condensation in the presence of hydrogen chloride gas using 3-mercaptopropionic acid as a co-catalyst. Meanwhile, Patent Document 2 reports an experimental example of the production of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane (hereinafter sometimes referred to as "Compound A"), a type of tetrakisphenol compound.

[0003] JP-A-49-000250 JP-A-06-107769

[0004] Patent Document 2 describes the use of 49.1 g of 4HBPA in the reaction to obtain 230.0 g of compound A. However, the weight of the obtained substance is far greater than the theoretical production amount of compound A (molecular weight 688.45), 143.1 g, based on the amount of 4HBPA (molecular weight 236.18) used. From this, it is expected that the obtained compound A described in Patent Document 2 contains a large amount of solvent or substrate (2,6-xylenol). Furthermore, when the present inventors attempted to produce compound A using similar reaction conditions and procedures based on the description in Patent Document 2, it became clear that the production rate of compound A was extremely low, as described in Comparative Example 1 below. From these facts, it became clear that although Patent Document 2 describes that compound A was collected by filtration as a precipitate, it was extremely low in purity and appears to contain large amounts of solvent and substrate. Therefore, it is difficult to say that compound A suitable for industrial production was produced. The present invention has been made against the background of the above circumstances, and an object of the present invention is to provide an isolated form of Compound A suitable for industrial production.

[0005] The present inventors have intensively investigated methods for isolating Compound A, and as a result have found for the first time that Compound A can be isolated as crystals, thereby completing the present invention.

[0006] The present invention is as follows: 1. A crystal of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane. 2. The crystal according to 1., which has an endothermic peak onset temperature in the range of 277 to 289°C as determined by differential scanning calorimetry. 3. The crystal according to 1., which has 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 a powder X-ray diffraction peak pattern using Cu-Kα radiation. 4. A method for producing the crystals according to any one of 1. to 3., comprising a reactive crystallization step of producing 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane in a mixed solution containing 4 to 30 moles of 2,6-xylenol per mole of 2,2-bis(4-oxycyclohexyl)propane and an acid catalyst, and simultaneously precipitating the crystals.

[0007] The crystals of Compound A of the present invention have easy-to-handle properties and are therefore suitable for industrial production, and can be obtained efficiently as highly pure Compound A. Furthermore, because of their high bulk density, a large amount of Compound A can be filled into a container of a certain volume, resulting in excellent transport efficiency, storage efficiency, reaction efficiency, etc. The method for producing crystals of Compound A of the present invention not only enables Compound A to be isolated as crystals that are easy to handle and have a high bulk density, but also provides an industrially feasible and efficient production process, making it possible to produce highly pure Compound A.

[0008] 1 is a chart showing differential scanning calorimetry (DSC) data of the crystals of Compound A obtained in Example 1. FIG. 2 is a chart showing powder X-ray diffraction (PXRD) measurement of the crystals of Compound A obtained in Example 1.

[0009] The present invention will be described in detail below. The method for producing crystals of the present invention comprises a reaction to produce 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane in a mixed solution containing 4 to 30 moles of 2,6-xylenol per mole of 2,2-bis(4-oxycyclohexyl)propane and an acid catalyst, and a reactive crystallization step of precipitating the crystals. 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane (Compound A) according to the present invention is a compound having the following chemical structure:

[0010] <Reactive Crystallization Step> In the method for producing crystals of the present invention, Compound A is produced together with two equivalents of water by a dehydration condensation reaction between four equivalents of 2,6-xylenol and one equivalent of 4HBPA (2,2-bis(4-oxycyclohexyl)propane). The content of 2,6-xylenol in the mixed solution in the method for producing crystals of the present invention is preferably in the range of 5 to 25 moles, more preferably 6 to 22 moles, and particularly preferably 8 to 20 moles, per mole of 4HBPA. Using less than 4 moles of 2,6-xylenol is undesirable because the reaction is slow and, in addition to the target compound A, by-products such as polynuclear compounds formed by further condensation of 4HBPA and 2,6-xylenol are produced in large amounts. Using more than 30 moles of 2,6-xylenol improves the reaction rate, but also increases the amount of unreacted 2,6-xylenol recovered, reducing productivity. Furthermore, this is undesirable because crystal precipitation is slowed and the amount of compound A produced by the reaction does not reach its saturated solubility in the mixed solution, preventing crystal precipitation. The reaction temperature for producing compound A and the temperature for crystal precipitation are preferably in the range of 20 to 100°C, more preferably 30 to 80°C. The reaction pressure for producing Compound A and the pressure for precipitating crystals are typically normal pressure. However, depending on the boiling point of the organic solvent used, the reaction may be carried out under elevated or reduced pressure so that the reaction temperature falls within the above-mentioned range. Furthermore, when hydrogen chloride gas is used as the acid catalyst, the reaction may be carried out under elevated pressure. The method for mixing the raw materials and other ingredients used to prepare the mixed solution in the production method of the present invention is not particularly limited. Examples include a method in which all of the raw materials to be used are charged into a reaction vessel at once and mixed, or a method in which a solution containing a portion of the 2,6-xylenol to be used, an acid catalyst, and, if necessary, a co-catalyst and / or reaction solvent is mixed with a mixed solution containing the remaining amount of 4HBPA and 2,6-xylenol, and, if necessary, a reaction solvent. The latter mixing method is preferred from the viewpoints of reaction selectivity and the ability to control the precipitation rate of the crystals precipitated during the reaction. In this mixing method, it is preferable to carry out the mixing for a time period of 0.5 to 5 hours, and to carry out the reaction so that the raw materials are used in the amounts described above after mixing. The reaction time for producing Compound A varies depending on the amount of catalyst and the reaction temperature, but is typically 3 to 48 hours, and is preferably completed within 3 to 24 hours. The end point of the reaction to produce Compound A can be confirmed by liquid chromatography or gas chromatography.The reaction is preferably terminated when the unreacted 4HBPA disappears or when no increase in the target compound A is observed.

[0011] (Acid Catalyst) Either an inorganic acid or an organic acid can be used as the acid catalyst used in the method for producing the crystal of the present invention. Examples of inorganic acids include hydrogen chloride gas, hydrochloric acid, sulfuric acid, phosphoric acid, sulfuric anhydride, etc., and examples of organic acids include aromatic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid, alkanesulfonic acids having 1 to 4 carbon atoms such as methanesulfonic acid and ethanesulfonic acid, trifluoromethanesulfonic acid, trichloroacetic acid, etc. Other examples of acid catalysts that can be used include metal halides such as aluminum chloride and iron chloride, and solid acids such as cation exchange resins. Among these, it is preferable to use an inorganic acid. Among inorganic acids, hydrochloric acid is more preferred, and the amount of this inorganic acid used is preferably in the range of 3 to 18 moles, more preferably 5 to 15 moles, and even more preferably 5 to 12 moles, per mole of 4HBPA.

[0012] (Co-catalyst) In the method for producing crystals of the present invention, a thiol compound may be used as a co-catalyst in combination with an acid catalyst, if necessary. The thiol compound is a compound having a mercapto group, and is not particularly limited as long as it does not adversely affect the reaction selectivity, etc. Examples of such compounds include carboxylic acids having a mercapto group, such as 3-mercaptopropionic acid and thioglycolic acid; alkyl mercaptans having 1 to 12 carbon atoms, such as methyl mercaptan, 1-octanethiol (octyl mercaptan), and 1-dodecanethiol (lauryl mercaptan); and mercaptoalcohols, such as mercaptoethanol and mercaptobutanol. Among these, alkyl mercaptans having 1 to 12 carbon atoms, such as 1-octanethiol, are preferred. The thiol compound may also be used in the form of an aqueous solution of its sodium salt. The amount of the thiol compound used is preferably in the range of 0.01 to 0.5 moles per mole of 4HBPA. If the amount is less than 0.01 mole, the promoter cannot fully function, and if the amount exceeds 0.5 mole, the promoter cannot further function and the selectivity does not change substantially.

[0013] (Reaction Solvent) In the method for producing a crystal of the present invention, it is not necessary to use a reaction solvent if there are no problems with operability, but it may be used to improve operability during industrial production. The reaction solvent used affects the ease of precipitation of crystals of Compound A depending on the solubility of Compound A in the solvent, so it is preferable to select an appropriate reaction solvent in consideration of its solubility. Furthermore, in the reaction to produce Compound A, it is preferable that the solvent does not distill out of the reaction vessel at the reaction temperature and is inert to the reaction. Examples of solvents that can be used include aromatic hydrocarbons such as toluene, xylene, and benzene. The amount of the solvent used is in the range of 0.1 to 5 times by weight, preferably 0.1 to 3 times by weight, and more preferably 0.1 to 2 times by weight relative to 2,6-xylenol.

[0014] The mixture used in the method for producing crystals of the present invention may contain water, including water produced by the dehydration condensation reaction between 2,6-xylenol and 4HBPA, water derived from water contained in acid catalysts such as hydrochloric acid or phosphoric acid, and water added as a solvent. The water in the mixture may be dissolved in 2,6-xylenol to form a uniform layer, or may be present in excess of the 2,6-xylenol dissolution amount, resulting in layer separation. In either case, the amount of water contained may be large as long as it does not prevent the reaction from proceeding and crystal precipitation. The amount of water contained in the mixture used in the production method of the present invention is preferably 5 times or less by weight relative to the amount of 4HBPA used. Carrying out the reaction under dehydration conditions that can remove water from the reaction system, such as the water produced by the reaction and the water contained in the acid catalyst used, is preferred because the reaction proceeds more rapidly than without dehydration, the production of by-products is suppressed, and the target product can be obtained in a higher yield. The dehydration method is not particularly limited, but examples include dehydration by adding a dehydrating agent, dehydration under reduced pressure, and dehydration by azeotropy with a solvent under atmospheric or reduced pressure. The dehydrating agent that can be added as needed is not particularly limited, and examples thereof include organic dehydrating agents having an orthoester skeleton such as methyl orthoformate, ethyl orthoformate, methyl orthoacetate, ethyl orthopropionate, methyl ortho-n-butyrate, methyl ortho-i-butyrate, and 1,1,1-trimethoxyoctane; zeolites such as molecular sieve (3A) and molecular sieve (4A); and inorganic anhydrous salts that can contain water of crystallization in the molecule, 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).

[0015] In the production method of the present invention, seed crystals may not be used when precipitating crystals. When seed crystals are used, there are no limitations on the crystals used as seed crystals, but it is preferable to use crystals of Compound A of the present invention that have been produced in advance by carrying out the production method of the present invention without seed crystals. The amount of seed crystals used is preferably in the range of 0.1 to 1.0% by weight based on Compound A produced by the reaction.

[0016] <Treatment after Completion of Reaction Crystallization Step> (Treatment before Isolation of Crystals) It is preferable to carry out post-treatments such as mixing the reaction mixture containing the crystals precipitated by the crystal production method of the present invention with an alkaline aqueous solution such as an aqueous sodium hydroxide solution to neutralize the acid catalyst used in the reaction, removing the separated aqueous layer and, if necessary, washing the oil layer containing the crystals with water, and removing the solvent and 2,6-xylenol used in excess in the reaction by distillation. The crystals can be isolated from the reaction mixture containing the precipitated crystals by, for example, a filtration operation.

[0017] (Treatment after isolation of crystals) The isolated crystals are preferably washed with water or an organic solvent. An aromatic hydrocarbon solvent is preferred as the organic solvent. The amount of the organic solvent used 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, relative to the amount of Compound A crystals. The solvent used can be removed by drying the obtained crystals. Drying can be carried out at a temperature preferably in the range of 20 to 160°C, more preferably in the range of 100 to 150°C, and even more preferably in the range of 110 to 145°C. Drying can be carried out under normal pressure or reduced pressure; however, for industrial use, drying under a reduced pressure of about 10 kPa is preferred, a reduced pressure of about 5 kPa is more preferred, and a reduced pressure of about 1.5 kPa is even more preferred. Drying under these reduced pressures is preferred because it allows for more efficient removal of the solvent used.

[0018] <Crystal of Compound A of the Present Invention> The crystal of Compound A of the present invention is preferably a crystal having one or both of the characteristics of "the onset temperature of the endothermic peak" and "the powder X-ray diffraction peak pattern", that is, an endothermic peak onset temperature in the range of 277 to 289°C as determined by differential scanning calorimetry, or a powder X-ray diffraction peak pattern using Cu-Kα radiation 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°. That is, the crystal of Compound A of the present invention is preferably any of the following embodiments (i) to (iii): (i) the onset temperature of the endothermic peak measured by differential scanning calorimetry is in the range of 277 to 289°C, (ii) the powder X-ray diffraction peak pattern using Cu-Kα radiation has diffraction peaks at diffraction angles 2θ of 15.2±0.2°, 17.5±0.2°, 18.3±0.2°, and 21.9±0.2°, and (iii) the onset temperature of the endothermic peak measured by differential scanning calorimetry is in the range of 277 to 289°C, and the powder X-ray diffraction peak pattern using Cu-Kα radiation has diffraction peaks at diffraction angles 2θ of 15.2±0.2°, 17.5±0.2°, 18.3±0.2°, and 21.9±0.2°. Among these, embodiment (iii) is more preferred. The onset temperature of the endothermic peak in differential scanning calorimetry of the crystal of the present invention is more preferably in the range of 279 to 287 ° C, even more preferably in the range of 280 to 286 ° C, and particularly preferably in the range of 281 to 285 ° C. In the powder X-ray diffraction peak pattern using Cu-Kα radiation of the present invention, in addition to the above peaks, it is more preferable that the diffraction angle 2θ further has diffraction peaks at 14.7 ± 0.2 °, 19.3 ± 0.2 °, and 19.6 ± 0.2 °. Note that the peak in powder X-ray diffraction using Cu-Kα radiation preferably has a relative intensity of 10 or more, more preferably 25 or more, based on the peak with the highest intensity. However, depending on the measurement device and conditions, or in the case of a mixture with other crystals, the relative intensity may vary, so the crystalline phase can be identified based on the analysis method of ordinary powder X-ray diffraction analysis.The purity of the crystalline Compound A is preferably 90.0% or more, more preferably 93.0% or more, and even more preferably 96.0% or more, as expressed by the ratio of the peak area of ​​Compound A to the peak areas of all components detected at a wavelength of 280 nm in high performance liquid chromatography (HPLC) analysis. The HPLC analysis method for the purity of the crystal of the present invention is a method according to the HPLC analysis (composition) in the analytical method of the Examples described below. The crystal of Compound A of the present invention is a crystalline solid and has a sufficiently high bulk density, making it useful because it is easy to handle. The loose bulk density of the crystal of Compound A of the present invention is 0.2 g / cm. ３ 0.45g / cm or more ３ The following range is preferred: 0.2 g / cm ３ 0.4g / cm or more ３ More preferably, the range is 0.25 g / cm ３ 0.4g / cm or more ３ More preferably, the range is 0.25 g / cm ３ 0.35g / cm or more ３ The following range is particularly preferred. 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. The content of 2,6-xylenol in the crystals of the present invention can be analyzed by a method in accordance with the HPLC analysis (quantitative analysis) in the analytical methods of the Examples described below.

[0019] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. <Analytical Methods> 1. High Performance Liquid Chromatography (HPLC) Analysis (1) Measurement of Purity of Compound A Crystals and Selectivity of Compound A in Reaction Solution (Composition) The purity of Compound A crystals is the peak area ratio (percentage) of Compound A to the peak areas of all components detected at a wavelength of 280 nm. The selectivity of Compound A in the reaction solution was calculated using the following calculation formula. [Calculation formula] (Selectivity) = (Peak area ratio of Compound A) ÷ {100 - (Peak area ratio of 2,6-xylenol)} × 100 (Method) A predetermined amount of sample was placed in a 50 mL volumetric flask and mixed with methanol up to the marked line to prepare a sample solution, which was analyzed using the following apparatus and conditions. (Sample amount) Reaction solution: 85 to 110 mg / 50 mL methanol, crystals: 40 to 50 mg / 50 mL methanol (Apparatus and conditions) Apparatus: Shimadzu HPLC LC-2030 / Shimadzu Corporation Column: Shim-Pack CLC-ODS, 6 mm x 15 cm / Shimadzu GLC Corporation Column oven temperature: 50°C Flow rate: 1.0 mL / min. Mobile phase: (A) 0.2% acetic acid aqueous solution, (B) methanol. Gradient conditions: Mobile phase (B) vol% (time from start of analysis) 50% (0 min) → 100% (30 min) → 100% (45 min). Sample injection volume: 20 μL. Detection wavelength: 280 nm. (2) Analysis of Solvent Content of Crystals (Quantitative Analysis) (Method) The toluene and 2,6-xylenol contents in the crystals were quantified using the absolute calibration curve method. 100 mg of crystals were placed in a 50 mL volumetric flask and mixed with methanol up to the marked line to prepare a sample solution. The sample solution was analyzed using the same equipment and conditions as in (1) above, except that the detection wavelengths were 280 nm for 2,6-xylenol and 254 nm for toluene.

[0020] 2. Differential Scanning Calorimetry (DSC) (Analysis Method) 2-3 mg of crystals were placed in an aluminum sample container, a lid was attached, and the container was pressed to create a sample. The resulting sample was analyzed using the following equipment and conditions. (Equipment and Conditions) Equipment: DSC7020 / Hitachi High-Tech Science Corporation Heating rate: 10°C / min. Measurement temperature range: 30-350°C. Measurement atmosphere: Nitrogen 50 mL / min.

[0021] 3. Powder X-ray diffraction (PXRD) analysis The crystals were thoroughly ground in a mortar and filled into a measurement cell. The obtained sample was analyzed using the following equipment and conditions. (Measurement conditions) Equipment: MiniFlex 600-C / Rigaku Corporation X-ray source: CuKα Scan axis: 2θ / θ Mode: Continuous Measurement range: 2θ = 5° to 90° Step: 0.02° Speed ​​measurement time: 10° / min. Entrance slit: 0.25° Receiving slit: 13.00 mm Tube voltage: 40 kV Tube current: 15 mA

[0022] 4. Measurement of bulk density of crystals (measurement method) The loose bulk density was calculated by dividing the weight of the packed crystals by the volume measured immediately after filling the crystals into a measuring cylinder. The packed bulk density was calculated by dividing the weight of the packed crystals by the volume measured after filling the crystals into a measuring cylinder and manually vibrating it 300 times.

[0023] Comparative Example 1 2,6-xylenol (165.3 g) was placed in a 1 L four-neck flask equipped with a thermometer, a stirrer, and a condenser, and the atmosphere was purged with nitrogen. Next, 3-mercaptopropionic acid (1.4 g) and concentrated hydrochloric acid (68.9 g) were placed in the flask, and the mixture was heated until the temperature inside the flask reached 61°C. Thereafter, 4HBPA (16.7 g) was added all at once, and the mixture was reacted with stirring at 59 to 61°C. 1.5 hours after the start of the reaction, the selectivity for compound A was 30%, and no crystal precipitation was observed.

[0024] Example 1 2,6-xylenol (165.3 g) was charged into a 1 L four-neck flask equipped with a thermometer, a stirrer, and a condenser, and the atmosphere was purged with nitrogen. Next, 3-mercaptopropionic acid (1.4 g) and concentrated hydrochloric acid (68.9 g) were charged, and the flask was heated until the temperature inside reached 61°C. Thereafter, 4HBPA (16.7 g) was added all at once, and the reaction was carried out with stirring at 59 to 61°C for 22 hours. The selectivity was 50% three hours after the start of the reaction, and no crystal precipitation was observed. However, the selectivity was 85% 22 hours after the start of the reaction, and crystal precipitation was observed. The reaction solution was neutralized by mixing 75% phosphoric acid (0.3 g), 16% aqueous sodium hydroxide solution (172.1 g), and concentrated hydrochloric acid (10.2 g), and heated to raise the liquid temperature to 88 ° C., and the mixture was separated into an oil layer containing crystals and an aqueous layer, and the aqueous layer (232.3 g) was removed. Toluene (142.7 g) was added dropwise over 1.5 hours to the resulting oil layer slurry containing crystals, while maintaining the liquid temperature in the range of 87 to 96 ° C. After the dropwise addition was completed, heating was stopped and the slurry was cooled to room temperature. 18 hours after the start of cooling, the slurry was centrifuged to separate the crystals. The filtered crystals were washed using water (46.2 g) and toluene (45.1 g) in that order. 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 4HBPA moles)). LC / MS (ESI) confirmed the production of Compound A with a molecular weight of 687.44 [deprotonated molecule]. HPLC analysis revealed that the purity of the obtained crystals was 96%. The crystals also contained 2,6-xylenol (1.4 wt%) and toluene (0.1 wt%). DSC and PXRD analyses of the obtained crystals were performed using the methods described above. The analytical charts are shown in Figures 1 and 2, respectively. In the DSC analysis, an endothermic peak (peak onset at 283°C) corresponding to the melting of the crystals was clearly observed. A diffraction pattern was also observed in the PXRD analysis, confirming that the crystals were crystals. Table 1 shows the diffraction angles 2θ (°) of the diffraction peaks that appeared and peaks with a relative intensity of 25 or more based on the peak with the greatest intensity. Furthermore, the bulk density of the obtained crystals was measured, and the loose bulk density was 0.30 g / cm ３ , the compacted bulk density is 0.45 g / cm ３ It was.

[0025] The crystals of the present invention obtained in the examples have a low solvent content, which can reduce the amount of solvent exposure during storage and transportation of Compound A and during the production of resins and derivatives using the same, thereby contributing to the health of workers handling the crystals and the preservation of the environment. In addition, the measurement results of the bulk density showed that the loose bulk density was 0.30 g / cm ３ As described above, it has been revealed that Compound A has a height that is sufficiently advantageous for industrial production, is easy to handle, and can be produced efficiently.

Claims

1. Crystals of 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane.

2. The crystal according to claim 1, having an endothermic peak onset temperature in the range of 277 to 289°C as determined by differential scanning calorimetry.

3. The crystal according to claim 1, which has 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 a powder X-ray diffraction peak pattern using Cu-Kα radiation.

4. A method for producing the crystals according to any one of claims 1 to 3, comprising a reaction for producing 2,2-bis-(4,4-bis-(3,5-dimethyl-4-hydroxyphenyl)cyclohexyl)propane in a mixed solution containing 4 to 30 moles of 2,6-xylenol per mole of 2,2-bis(4-oxycyclohexyl)propane and an acid catalyst, and a reactive crystallization step for precipitating the crystals.

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