2,2-bis(4-hydroxyphenyl)tridecane crystal and method for producing same

Abstract

The present invention addresses the problem of providing a 2,2-bis(4-hydroxyphenyl)tridecane crystal that has high thermal stability and sufficient fluidity and is suitable for industrial production. As a solution, the present invention provides a 2,2-bis(4-hydroxyphenyl)tridecane crystal that exhibits an endothermic peak with a peak top temperature falling within the range of 84-96°C based on differential scanning calorimetric analysis.

Description

Crystals of 2,2-bis(4-hydroxyphenyl)tridecane and method for producing the same

[0001] The present invention relates to 2,2-bis(4-hydroxyphenyl)tridecane crystals and a method for producing the same.

[0002] Bisphenol compounds are useful compounds widely used as raw materials for polycarbonate and epoxy resins. They are also important raw materials for obtaining polycarbonate and epoxy resins with properties such as high mechanical strength and impact resistance, excellent transparency, heat resistance and dimensional stability, and electrical insulation. These resins are highly anticipated because they can meet the high-performance requirements of automotive parts, electronic equipment, building materials, and medical devices. Furthermore, these bisphenol compounds are desirable to have sufficient thermal stability during storage and transportation, and to have a small difference between loose and hard bulk density from the perspective of powder fluidity.

[0003] Japanese Patent Publication No. 29-002430, International Publication No. 2017 / 099227, U.S. Patent No. 6,372877, and British Patent Application Publication No. 959286.

[0004] Patent Document 1 describes how the compound according to the present invention was obtained by mixing 100 parts of undecylmethyl ketone and 100 parts of carbolic acid, adding 500 parts of approximately 80% sulfuric acid, and heating at 80°C for approximately 5 hours, resulting in a soft, waxy substance with a melting point of 30 degrees. Patent Document 2 describes a method for producing the compound according to the present invention (synthesis Example 6), in which the compound was purified by silica gel column chromatography using ethyl acetate and hexane as the developing solvent, and the solvent was removed by distillation to obtain a colorless, viscous liquid. In other words, crystals of the compound according to the present invention have not been reported to date. Furthermore, although Patent Documents 3 and 4 describe methods for producing bisphenol compounds having a long-chain alkyl group with 11 carbon atoms, which is different from the compound according to the present invention, the melting points of the crystals are 75-77°C and 59-60°C, respectively, and these crystals cannot be said to have sufficient thermal stability during storage or transportation. The present invention was made against the background described above, and aims to obtain 2,2-bis(4-hydroxyphenyl)tridecane (hereinafter sometimes referred to as "compound A") as crystals that have high thermal stability and sufficient fluidity suitable for industrial production.

[0005] The inventors diligently investigated methods for crystallizing 2,2-bis(4-hydroxyphenyl)tridecane and, as a result, discovered that compound A could be obtained as a crystal with high thermal stability and sufficient fluidity suitable for industrial production, thus completing the present invention.

[0006] The present invention is as follows: 1. Crystals of 2,2-bis(4-hydroxyphenyl)tridecane, wherein the peak top temperature of the endothermic peak determined by differential scanning calorimetry analysis is in the range of 84 to 96°C. 2. The crystals according to 1, wherein the powder X-ray diffraction peak pattern using Cu-Kα rays has diffraction peaks at diffraction angles 2θ of 17.1±0.2°, 20.3±0.2°, and 22.8±0.2°. 3. The crystals according to 1 or 2, wherein the phenol content is 1.0% by weight or less. 4. A method for producing the crystals according to 1, comprising a crystallization step of precipitating crystals of 2,2-bis(4-hydroxyphenyl)tridecane from a crystallization solution containing 2,2-bis(4-hydroxyphenyl)tridecane and a mixed solvent of an aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and an aromatic hydrocarbon solvent having 6 to 9 carbon atoms.

[0007] The present invention makes it possible to obtain compound A as a crystal with high thermal stability and sufficient fluidity suitable for industrial production. The manufacturing method of the present invention not only allows for the isolation of compound A as a crystal with good handling properties, but also provides an industrially feasible and efficient manufacturing process, enabling the production of compound A as a crystal with high thermal stability and sufficient fluidity suitable for industrial production.

[0008] This figure shows the differential scanning calorimetry (DSC) analysis chart of the crystal of compound A obtained in Example 1. This figure shows the powder X-ray diffraction (PXRD) analysis chart of the crystal of compound A obtained in Example 1. This figure shows the differential scanning calorimetry (DSC) analysis chart of the crystal of compound A obtained in Example 2.

[0009] The present invention will now be described in detail. The 2,2-bis(4-hydroxyphenyl)tridecane (compound A) according to the present invention is a compound having the following chemical structure.

[0010] <Reaction Step> There are no limitations on the method for producing compound A according to the present invention, but for example, it can be produced by a reaction step in which 1 equivalent of 2-tridecanone and 2 equivalents of phenol are subjected to a dehydration condensation reaction. The amount of phenol used in the reaction step is preferably in the range of 2 moles to 12 moles, and more preferably in the range of 2 moles to 10 moles, per mole of 2-tridecanone. The reaction temperature for producing compound A is preferably in the range of 10 to 80°C, and more preferably in the range of 30 to 50°C, and does not exceed the boiling point of the reaction solvent used. The reaction pressure for producing compound A is usually carried out under atmospheric pressure, but depending on the boiling point of the organic solvent used, it may be carried out under pressurized or reduced pressure so that the reaction temperature is within the above range. Furthermore, when hydrogen chloride gas is used as an acid catalyst, it may be carried out under pressurized pressure. The method of mixing the raw materials in the reaction step is not particularly limited. For example, a mixing method in which the entire amount of raw materials to be used is charged into the reaction vessel at once, or a mixing method in which a mixture containing the remaining amount of 2-tridecanone and phenol, and optionally the reaction solvent, is added to a solution containing a portion of the phenol to be used, an acid catalyst, and optionally a co-catalyst and reaction solvent. The latter mixing method is preferred from the viewpoint of reaction selectivity and the ability to adjust the reaction amount per unit time. In this mixing method, it is preferable to carry out the mixing within a range of 0.5 to 5 hours, and then carry out the reaction so that the amount of raw materials used after mixing is as described above. The reaction time for producing compound A depends on the amount of catalyst and the reaction temperature, but is usually in the range of 1 to 48 hours, although it is preferable that the reaction be completed within the range of 3 to 24 hours. The endpoint of the reaction for producing compound A can be confirmed, for example, by liquid chromatography analysis or gas chromatography analysis. It is preferable to define the endpoint of the reaction as the point at which unreacted 2-tridecanone disappears or when no increase in the target compound A is observed.

[0011] (Acid Catalyst) An acid catalyst may be used in the reaction step, and either an inorganic acid or an organic acid catalyst can be used. Examples of inorganic acids include hydrogen chloride gas, hydrochloric acid, sulfuric acid, phosphoric acid, sulfuric anhydride, and heteropoly acids such as phosphomolybdic acid, phosphotungstic acid, and silicic acid. Examples of organic acids include aromatic sulfonic acids such as benzenesulfonic acid and p-toluenesulfonic acid, alkanesulfonic acids with 1 to 4 carbon atoms such as methanesulfonic acid and ethanesulfonic acid, trifluoromethanesulfonic acid, and trichloroacetic acid. In addition, metal halides such as aluminum chloride and iron chloride, or solid acids such as cation exchange resins can be used as acid catalysts. Among these, the use of inorganic acids is preferred. Among inorganic acids, hydrogen chloride gas or hydrochloric acid is more preferred, and hydrogen chloride gas is particularly preferred. The amount of inorganic acid used is preferably in the range of 2.0 moles or less, and more preferably in the range of 1.0 mole or less, per mole of 2-tridecanone.

[0012] (Reaction Solvent) In the reaction step described above, a reaction solvent does not need to be used if there are no problems with operability, but it may be used to improve operability during industrial production. The reaction solvent used is preferably selected appropriately according to the solubility of the raw materials and compound A, which is the product used in the reaction step. It is also preferable that the solvent does not distill out of the reaction vessel at the reaction temperature in the reaction to produce compound A and is inert to the reaction. Examples of usable solvents include lower alcohols such as methanol, ethanol, and isopropanol, and water, with these solvents being preferred and water being particularly preferred. The amount of solvent used is preferably in the range of 0.2 times the weight or less of the amount of phenol used in the reaction, more preferably in the range of 0.1 times the weight or less, and particularly preferably 0.05 times the weight or less.

[0013] (Co-catalyst) In the above reaction step, a thiol compound may be used as a co-catalyst in combination with the 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-octanthiol (octyl mercaptan), and 1-dodecanethiol (lauryl mercaptan), and mercapto alcohols such as mercaptoethanol and mercaptobutanol. Among these, alkyl mercaptans having 1 to 12 carbon atoms such as 1-octanthiol are preferred, methyl mercaptan, 1-octanthiol (octyl mercaptan), and 1-dodecanethiol (lauryl mercaptan) are more preferred, and 1-dodecanethiol (lauryl mercaptan) is particularly preferred. These compounds may also be used in the form of aqueous solutions, such as sodium salts. The amount of thiol compound used is preferably in the range of 0.01 to 0.5 moles, and more preferably in the range of 0.01 to 0.1 moles, per mole of 2-tridecanone.

[0014] <Post-reaction processing> After the reaction process, it is preferable to perform post-treatment on the reaction-completed mixture, for example, by mixing an organic solvent that dissolves compound A contained in the reaction solution and separates it from water to obtain a homogeneous solution containing compound A, then mixing it 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 washing the oil layer with water if necessary, and removing the solvent used in the reaction process and oil-water separation / washing operations, as well as excess phenol used in the reaction, by distillation. After that, compound A can be isolated by operations such as crystallization or separation by column chromatography. The crystals of compound A of the present invention can be produced by performing the crystallization process described later using the liquid obtained by treating the reaction solution containing compound A as described above, the solid of compound A obtained by conventionally known methods, the crystals of compound A of the present invention, or a mixture of crystalline polymorphs containing the same.

[0015] <Method for producing crystals of compound A of the present invention: crystallization step> The method for producing crystals of compound A of the present invention is characterized by comprising a crystallization step in which crystals of compound A are precipitated from a crystallization solution containing compound A (2,2-bis(4-hydroxyphenyl)tridecane) obtained by the method described above and a mixed solvent of an aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and an aromatic hydrocarbon solvent having 6 to 9 carbon atoms. Examples of aliphatic saturated hydrocarbon solvents having 5 to 10 carbon atoms include chain-like aliphatic saturated hydrocarbon solvents having 5 to 10 carbon atoms such as pentane, hexane, heptane, octane, and isooctane, and cyclic aliphatic saturated hydrocarbon solvents having 5 to 10 carbon atoms such as cyclohexane. Examples of aromatic hydrocarbon solvents having 6 to 9 carbon atoms include benzene, toluene, and xylene. In the crystallization step of the present invention, a mixed solvent of a chain-like aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and an aromatic hydrocarbon solvent having 6 to 9 carbon atoms is preferred as the solvent. More preferably, a mixed solvent of at least one selected from pentane, hexane, heptane, octane, and isooctane as the chain-like aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and at least one selected from benzene and toluene as the aromatic hydrocarbon solvent having 6 to 9 carbon atoms is preferred, and a mixed solvent of heptane and toluene is particularly preferred. The mixing ratio of the mixed solvent of aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and aromatic hydrocarbon solvent having 6 to 9 carbon atoms is preferably in the range of 0.5 to 10.0 times the weight of the aromatic hydrocarbon solvent, more preferably in the range of 0.5 to 5.0 times the weight of the aromatic hydrocarbon solvent, and even more preferably in the range of 0.5 to 3.0 times the weight of the aromatic hydrocarbon solvent. The amount of crystallization solvent used is in the range of 0.5 to 5.0 times the weight of compound A used, more preferably in the range of 0.5 to 3.0 times, even more preferably in the range of 0.5 to 2.0 times, and particularly preferably in the range of 1.0 to 2.0 times.The crystallization solution may contain water, which may be present due to washing with water as described later, or other organic solvents (such as phenol used as a raw material, lower alcohols such as methanol and ethanol, and aromatic hydrocarbon solvents such as benzene, toluene, and xylene), as long as they do not interfere with the effects of the present invention. However, the total amount of compound A and the crystallization solvent in the crystallization solution is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 95% by weight or more, based on the total weight of the crystallization solution. It is particularly preferable to prepare the crystallization solution with compound A without containing other organic solvents. Before precipitating the crystals of compound A by the crystallization step, the crystallization solution may, if necessary, be mixed with water to remove impurities such as water-soluble metals, salts, and organic substances, and the separated aqueous layer may be removed or the oil layer may be washed with water. Treatment such as vacuum distillation or steam distillation may also be performed to remove the solvent and phenol used in the reaction. Such treatment is preferable. When precipitating the crystals, it is not necessary to use seed crystals, but it is preferable to use seed crystals. There are no restrictions on the crystal used as the seed crystal, but the crystal of the present invention obtained without a seed crystal initially may be used as the seed crystal. The amount of seed crystal used is preferably in the range of 0.1 to 1.0% by weight relative to compound A to be precipitated. The temperature at which crystals are precipitated from the prepared crystallization solution as described above depends on the boiling point of the crystallization solvent used, but is preferably in the range of 5 to 60°C, not exceeding the boiling point. The crystal precipitation temperature is more preferably in the range of 5 to 40°C, even more preferably in the range of 10 to 40°C, and particularly preferably in the range of 15 to 40°C. After the crystals begin to precipitate, it is preferable to maintain the same temperature to increase the amount of precipitated crystals. There are no particular restrictions on the holding time, but it is usually in the range of 1 to 48 hours, and preferably in the range of 3 to 24 hours.

[0016] After increasing the amount of precipitated crystals, the liquid containing the crystals can be cooled, and the final cooling temperature is preferably 10 to 30°C. The cooling rate is preferably in the range of 3 to 20°C / hour, and more preferably in the range of 5 to 15°C / hour. The precipitated crystals may be reheated to a temperature at which the crystals dissolve and then recooled in order to dissolve the fine crystals and improve the slurry properties and particle size distribution, and can be isolated by filtration. The filtered crystals are preferably washed with water or an organic solvent. The organic solvent used is preferably the crystallization solvent used in the crystallization step. The amount of organic solvent used is preferably in the range of 0.5 to 10.0 times the weight of the crystals of compound A, more preferably in the range of 0.5 to 5.0 times the weight, even more preferably in the range of 1.0 to 5.0 times the weight, and particularly preferably in the range of 1.0 to 3.0 times the weight.

[0017] (Post-crystal isolation treatment) The filtered crystals can be dried under predetermined conditions to remove any solvent adhering to them. The drying temperature is in the range of 10 to 70°C, preferably 10 to 50°C, more preferably 20 to 45°C, and most preferably 30 to 45°C. Drying can be done under atmospheric pressure or reduced pressure, but in industrial applications, reduced pressure of about 20 kPa is preferred, more preferably about 10 kPa, even more preferably about 5 kPa, and most preferably about 2 kPa, as this allows for the removal of the solvent used.

[0018] <Crystals of Compound A of the Present Invention> The crystals of Compound A (2,2-bis(4-hydroxyphenyl)tridecane) of the present invention have a peak top temperature of the endothermic peak determined by differential scanning calorimetry analysis in the range of 84 to 96°C. The peak top temperature is more preferably in the range of 85 to 95°C, even more preferably in the range of 86 to 94°C, and particularly preferably in the range of 87 to 93°C. Furthermore, the crystals of Compound A of the present invention preferably have diffraction peaks at diffraction angles 2θ of 17.1±0.2°, 20.3±0.2°, and 22.8±0.2° in the powder X-ray diffraction peak pattern using Cu-Kα rays. In the powder X-ray diffraction peak pattern using Cu-Kα rays, it is more preferable that diffraction peaks are present at diffraction angles 2θ of 11.9±0.2°, 15.0±0.2°, and 15.5±0.2° in addition to the peaks mentioned above, and even more preferable that diffraction peaks are present at 9.5±0.2°, 18.7±0.2°, 19.0±0.2°, and 24.1±0.2° in addition to these peaks. It is preferable that the relative intensity of the powder X-ray diffraction peaks using Cu-Kα rays is 10 or higher, and more preferably 25 or higher, with the peak with the highest intensity as the reference (relative intensity 100). However, the relative intensity may fluctuate depending on the measurement device and conditions, and in the case of mixtures with other crystals. Therefore, the crystalline phase can be identified based on the analysis method of normal powder X-ray diffraction analysis. The purity of compound A in the crystals of the present invention is preferably such that the ratio of the peak area of ​​compound A to the peak area of ​​all components detected at a wavelength of 280 nm in high-performance liquid chromatography (HPLC) analysis is 95.0% or higher, more preferably 97.0% or higher, even more preferably 98.0% or higher, and particularly preferably 99.0% or higher. The method for HPLC analysis of the purity of the crystals of the present invention is the same as the HPLC analysis method described in the examples below.In the crystal of Compound A of the present invention, phenol used as a raw material may be contained, and the content of the phenol is preferably 1.0% by weight (10,000 ppm) or less, more preferably 0.5% by weight (5,000 ppm) or less, even more preferably 0.1% by weight (1,000 ppm) or less, and particularly preferably 0.05% by weight (500 ppm) or less. The analysis of the content of phenol in the crystal of the present invention can be carried out by a method according to the HPLC analysis (quantification) in the analysis method of the following examples. In the crystal of Compound A of the present invention, an aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms or an aromatic hydrocarbon solvent having 6 to 9 carbon atoms used as a crystallization solvent may be contained, and the content thereof is preferably 1.0% by weight (10,000 ppm) or less, more preferably 0.5% by weight (5,000 ppm) or less, even more preferably 0.1% by weight (1,000 ppm) or less, and particularly preferably 0.05% by weight (500 ppm) or less. The analysis of the content of the aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms or the aromatic hydrocarbon solvent having 6 to 9 carbon atoms in the crystal of the present invention can be carried out by a method according to the HPLC analysis (quantification) in the analysis method of the following examples. The crystal of Compound A of the present invention has a loose bulk density of 0.15 g / cm³. ３ to 0.50 g / cm³ ３ is preferably in the range of, more preferably 0.20 g / cm³ ３ to 0.50 g / cm³ ３ is more preferably in the range of, even more preferably 0.25 g / cm³ ３ to 0.45 g / cm³ ３ is even more preferably in the range of, particularly preferably 0.30 g / cm³ ３ to 0.45 g / cm³ ３ The crystal of Compound A of the present invention has a packed bulk density of 0.15 g / cm³ ３ to 0.50 g / cm³ ３ is preferably in the range of, more preferably 0.20 g / cm³ ３ to 0.50 g / cm³ ３ is more preferably in the range of, even more preferably 0.25 g / cm³ ３ to 0.45 g / cm³ ３It is even more preferable that the range be 0.30 g / cm³. ３ ~0.45 g / cm ３ It is particularly preferable that the range is within this range. Highly fluid powders naturally fill the gaps between particles simply by gently filling them into a bulk density measuring container, resulting in a small difference between loose and firm bulk density. The crystals of compound A of the present invention exhibit excellent fluidity, which is also beneficial because of the small difference between loose and firm bulk density. The difference between loose and firm bulk density of the crystals of compound A of the present invention is 0.20 g / cm³. ３ Preferably, it should be within 0.15 g / cm³. ３ It is more preferable that it be within 0.10 g / cm³. ３ It is even more preferable that it be within the range. The crystals of compound A of the present invention preferably have excellent hue, and in a methanol solution containing 20% ​​by mass of the crystals of compound A, the Hazen unit color number (APHA) is preferably 200 or less, more preferably 150 or less, even more preferably 100 or less, even more preferably 50 or less, and particularly preferably 20 or less.

[0019] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. <Analysis Method> 1. High-performance liquid chromatography (HPLC) analyzer and conditions (1) Apparatus and conditions High-performance liquid chromatography analyzer Prominence UFLC (manufactured by Shimadzu Corporation) Column oven: CTO-20A Detector: SPD-20A Column: HALO C18 column 3.0 × 75 mm Oven temperature: 50℃ Flow rate: 0.7 mL / min. Mobile phase: (A) 0.2 vol% aqueous acetic acid solution, (B) methanol gradient conditions: (B) volume% (time from start of analysis) 50% (0 min.) → 100% (7.5 min.) → 100% (7.5 min.) Sample injection volume: 5 μL Detection wavelength: 280 nm (2) Measurement of selectivity of compound A in the reaction solution 300 mg of the reaction solution was taken into a 50 mL volumetric flask and mixed with methanol up to the mark on the volumetric flask to dissolve it. The obtained sample solution was analyzed using the apparatus and conditions of (1) above, and the composition was calculated based on the detected peak area. (3) Measurement of the purity of compound A crystals and the amount of phenol contained 50 mg of crystals was taken into a 50 mL volumetric flask and mixed with methanol up to the mark on the volumetric flask to dissolve it. The obtained sample solution was analyzed using the apparatus and conditions of (1) above. The area percentage of compound A in the HPLC analysis was taken as the purity of compound A. Furthermore, the amount of phenol contained was measured using the absolute calibration curve method.

[0020] 2. Headspace Gas Chromatography (HS-GC) (1) HS-GC analyzer and conditions Gas chromatography system: GC-2010 Plus / Shimadzu Corporation Column: InertCap-1 60m x 0.25mmΦ / GL Sciences Inc. Film thickness: 0.25μm Detector: FID Vaporization chamber temperature: 300℃ Detector temperature: 310℃ Column temperature: 40℃ Column heating conditions (holding time): 40℃ (10 min) → 20℃ / min → 300℃ (5 min) Makeup gas (nitrogen) flow rate: 30.0 mL / min Hydrogen flow rate: 40.0 mL / min Air flow rate: 400.0 mL / min Carrier gas: Nitrogen Pressure: 118 kPa Column flow rate: 0.92 mL / min Linear velocity: 19.9 cm / sec Total flow rate: 8.5 mL / min Split ratio: 5・HS sampler apparatus: TurboMatrixHS40 / PerkinElmer Co., Ltd. HS carrier gas pressure: 154.0 kPa Oven temperature: 100°C Needle temperature: 105°C Transfer temperature: 105°C Holding time: 20 minutes Pressurization time: 3 minutes Withdrawal time: 0.5 minutes Injection time: 0.05 minutes (2) Measurement of solvent content of the crystals of compound A (toluene, heptane) Samples of multiple N-methylpyrrolidone solutions with different concentrations were prepared for the components to be quantified (toluene, heptane) and analyzed using the apparatus and conditions described in (1) above. A calibration curve was created from the relationship between the sample concentration of the component to be quantified and the peak area detected by HS-GC analysis. 0.5 g of crystals was dissolved in 9.5 g of N-methylpyrrolidone, and 3.0 g of the resulting sample solution was analyzed using the apparatus and conditions described in (1) above. The amount of solvent contained in the crystals was calculated using the calibration curve.

[0021] 3. Differential Scanning Calorimetry (DSC) (Analysis Method) 2-5 mg of crystals were collected in an aluminum sample container, the lid was attached, and the container was pressed to prepare a sample. The obtained sample was analyzed using the following equipment and conditions. (Equipment and Conditions) Equipment: DSC7020 / Hitachi High-Tech Science Co., Ltd. Heating rate: 10°C / min. Measurement temperature range: 30-300°C Measurement atmosphere: 50 mL / min. nitrogen

[0022] 4. Powder X-ray diffraction (PXRD) analysis: The crystals were thoroughly ground in a mortar and packed into the 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: 40kV Tube current: 15mA

[0023] 5. In the bulk density measurement example, the value of the loose bulk density of the crystal obtained was calculated by dividing the volume measured immediately after filling the graduated cylinder with the weight of the filled crystal. In the example, the value of the hard bulk density of the crystal obtained was calculated by dividing the volume measured after manually vibrating the graduated cylinder 300 times after filling it with the weight of the filled crystal.

[0024] <Example 1> In a 3 L four-necked flask equipped with a thermometer, stirrer, and condenser, phenol (1139.1 g) and 75% phosphoric acid (3.0 g) were charged, and the flask was purged with nitrogen. Next, hydrogen chloride gas was blown in over 1 hour at a liquid temperature of 15-30°C, and 1-dodecanethiol (15.0 g) was added at 15-30°C. Meanwhile, a dropping solution was prepared by mixing 2-tridecanone (299.5 g) and phenol (285.3 g). The dropping solution was added over 1 hour while the liquid temperature in the four-necked flask was kept in the range of 35-43°C. After that, seed crystals were added, and the mixture was stirred at that temperature for another 4 hours. The selectivity of compound A in the reaction solution at the end of stirring was 95%. After adding toluene (142.9 g), the reaction solution was neutralized with a 10% sodium hydroxide aqueous solution. The liquid was heated to a temperature of 60-65°C, and the aqueous layer (234.1 g) was removed from the two separated layers. The resulting oil layer was then distilled by heating to an internal pressure of 2.0 kPa and a liquid temperature of 140°C to distill off a liquid containing toluene and phenol (1338.5 g). Subsequently, toluene (290.0 g) and water (298.7 g) were added. The liquid was heated to a temperature of 70-75°C, and the aqueous layer (288.0 g) was removed from the two separated layers. Water (300.3 g) was added, and the mixture was washed with water using the same procedure. Heptane (581.7 g) was added to the resulting oil layer, and after cooling to 30°C, seed crystals (0.4 g) were added, and the mixture was further cooled to 15°C. After stirring at 15°C for 1 hour, the mixture was heated and cooled again. The precipitated crystals were filtered off by centrifugal filtration and washed with toluene and heptane (weight ratio 1:1, total 204.0 g). The resulting solvent-containing crystals (345.2 g) were dried in an evaporator under reduced pressure of 1 kPa or less at 30°C for 1 hour and then at 60°C for 4 hours. The obtained crystals were again dissolved in heptane (250.0 g) and toluene (100.0 g), heated and cooled, and then stirred overnight. The precipitated crystals were filtered off by centrifugal filtration and washed with toluene and heptane (weight ratio 1:1, total 99.0 g). The resulting solvent-containing crystals (254.7 g) were dried in an evaporator under reduced pressure of 1 kPa or less at 30°C for 1 hour and then at 60°C for 4 hours. Through these operations, 236.0 g of crystals (yield 42%) were obtained.The purity of the obtained compound A crystals, as determined by the HPLC analysis described above, was 99.9 area%. The crystals contained heptane (95 ppm) and toluene (58 ppm). The phenol content was less than 33 ppm. The chart of the obtained crystals from DSC analysis is shown in Figure 1, and the chart of the PXRD analysis is shown in Figure 2. In the DSC analysis of the obtained crystals, an endothermic peak was observed at 91°C (peak top temperature), which is considered to correspond to the melting of the crystal. A diffraction pattern was also observed in the PXRD analysis, confirming that it was a crystal. Table 1 shows the diffraction angle 2θ (°) of the observed diffraction peaks and the peaks with a relative intensity of 25 or higher, based on the peak with the highest intensity. The loosened bulk density of the crystals was 0.37 g / cm³. ３ It is firm, and its bulk density is 0.43 g / cm³. ３ The small difference between the loose and hard bulk densities suggested high fluidity. This makes it useful when using the crystalline material of the present invention as a resin raw material, as it can suppress adhesion to the raw material inlet of the manufacturing equipment and the resulting clogging, thereby improving manufacturing efficiency. A 20% methanol solution of the obtained crystals was prepared, and the Hazen color number (APHA) of the solution was measured to be 5, indicating excellent hue.

[0025]

[0026] <Example 2> The same procedure as in Example 1 was followed up to the step of washing with water. Then, heptane was added and the mixture was cooled to 10°C and stirred for 4 hours. The precipitated crystals were filtered off by centrifugal filtration and washed with toluene and heptane (weight ratio 1:1). The crystals containing the solvent obtained by filtration were dried under reduced pressure of 1 kPa or less using an evaporator at 30°C for 1 hour and at 60°C for 4 hours to obtain crystals (yield 14%). The phenol content was 375 ppm. The chart of the DSC analysis of the obtained crystals is shown in Figure 3. In the DSC analysis of the obtained crystals, an endothermic peak was observed at 88°C (peak top temperature), which is considered to correspond to the melting of the crystals.

[0027] The present invention makes it possible to obtain compound A as a crystal with high thermal stability and sufficient fluidity suitable for industrial production. The manufacturing method of the present invention not only allows for the isolation of compound A as a crystal with good handling properties, but also provides an industrially feasible and efficient manufacturing process, enabling the production of compound A crystals with high thermal stability and sufficient fluidity suitable for industrial production.

Claims

1. Crystals of 2,2-bis(4-hydroxyphenyl)tridecane, in which the peak top temperature of the endothermic peak determined by differential scanning calorimetry is in the range of 84 to 96°C.

2. The crystal according to claim 1, wherein the powder X-ray diffraction peak pattern using Cu-Kα rays has diffraction peaks at diffraction angles 2θ of 17.1±0.2°, 20.3±0.2°, and 22.8±0.2°.

3. The crystal according to claim 1 or 2, wherein the phenol content is 1.0% by weight or less.

4. A method for producing crystals according to claim 1, comprising a crystallization step of precipitating crystals of 2,2-bis(4-hydroxyphenyl)tridecane from a crystallization solution containing 2,2-bis(4-hydroxyphenyl)tridecane and a mixed solvent of an aliphatic saturated hydrocarbon solvent having 5 to 10 carbon atoms and an aromatic hydrocarbon solvent having 6 to 9 carbon atoms.

Images