KR20230123465A - Crystals of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and method for producing the same - Google Patents

Abstract

An object of the present invention is to provide a crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane with good handling properties and a method for producing the same.
In order to solve the above problems, the present invention is a crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane having an endothermic maximum temperature in the range of 195 to 225 ° C by differential scanning calorimetry. provides

Description

Crystals of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and method for producing the same

The present invention relates to a crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and a method for producing the same.

It is known that 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane can be used as a raw material monomer for polyphenylene ether and epoxy resin (for example, Patent Document 1), No details are known about the physical properties of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane.

Japanese Unexamined Patent Publication No. Hei 01-268714 Japanese Unexamined Patent Publication No. Hei 06-107577 Japanese Unexamined Patent Publication No. Hei 09-176068

Patent Document 2 describes a method for producing 4,4',4"-ethylidinetris-2-methylphenol, and a mixed solvent of an aromatic hydrocarbon solvent and an aliphatic ketone solvent is used in the crystallization operation. However, these The crystallization solvent is not suitable for industrial production from problems such as low recycling efficiency and high production cost, and has been a major problem in industrial production.

Further, in Patent Document 3, regarding a method for producing a tris(4-hydroxyphenyl) compound, a trisphenol reaction mixture can be mixed with a non-solvent for trisphenol to precipitate trisphenol from the reaction solution, and the like. are listed. As a specific example, in the examples, the presence or absence of precipitation using various solvents was checked for 1,1,1-tris(4-hydroxyphenyl)ethane among the tris(4-hydroxyphenyl) compounds, and methylene chloride and 1,2-dichloroethane are the most preferred ones.

The inventors of the present invention found that even if these methods were applied to 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane, which is the compound of the present invention, crystals could not be obtained as in the comparative example described later. made clear

The present invention has been made against the background of the above circumstances, and an object thereof is to provide a crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane with good handling properties and a method for producing the same. .

As a result of intensive studies to solve the above problems, the present inventors have found that 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane can be crystallized with a single solvent, and the present invention has been developed. completed.

The present invention is as follows.

1. A crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane having an endothermic maximum temperature in the range of 195 to 225°C as determined by differential scanning calorimetry.

2. The crystal according to 1., which has a loose bulk density in the range of 0.25 to 0.6 g/cm 3 .

3. In the powder X-ray diffraction peak pattern by Cu-Kα rays, the diffraction angles 2θ have diffraction peaks at 11.0 ± 0.2 °, 12.9 ± 0.2 °, 16.1 ± 0.2 °, 17.5 ± 0.2 ° and 22.2 ± 0.2 ° , the crystals described in 1. or 2.

4. A solution containing 100 parts by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 250 to 1500 parts by weight of an aromatic hydrocarbon solvent is cooled to precipitate crystals. , The method for producing a crystal according to any one of 1. to 3.

The present invention clarifies for the first time the physical properties of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane, which were previously unclear, as crystals, and is very useful because the crystals have excellent handling properties. do.

In particular, since the crystal of the present invention can be obtained by crystallization using a single solvent, it becomes possible to significantly reduce raw material costs in industrial production, and is very useful.

1 is a graph showing differential scanning calorimetry (DSC) data of crystals obtained in Example 1.
2 is a graph showing differential scanning calorimetry (DSC) data of the crystals obtained in Example 2.
Fig. 3 is a chart showing powder X-ray diffraction data of crystals obtained in Example 2 by Cu-Kα rays.

The present invention is explained in detail below.

1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane in the present invention is a compound having the following chemical structure.

<Synthetic method>

1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane can be obtained by a conventionally known production method. Specifically, as shown in the reaction formula below, it can be obtained by a condensation reaction between 4-hydroxy-3,5-dimethylacetophenone and 2,6-dimethylphenol.

As the amount of 2,6-dimethylphenol relative to 4-hydroxy-3,5-dimethylacetophenone in the above reaction, 2,6-dimethylphenol per mole of 4-hydroxy-3,5-dimethylacetophenone The amount of phenol is preferably 2 to 50 moles, more preferably 3 to 30 moles, still more preferably 4 to 20 moles.

The reaction temperature is preferably 20 to 70°C, more preferably 30 to 60°C. The reaction is usually carried out under normal pressure, but depending on the boiling point of the solvent used, it may be carried out under increased pressure or reduced pressure so that the reaction temperature is within the above range.

In the above reaction, it is preferable to use an acidic catalyst such as an inorganic acid, an organic acid, a metal halide or a solid acid such as a cation exchange resin as a catalyst. Specific examples thereof include hydrogen chloride gas, hydrochloric acid, sulfuric acid, phosphoric acid, anhydrous sulfuric acid, p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, trichloroacetic acid, aluminum chloride, and iron chloride. . When hydrogen chloride gas is used, dry hydrogen chloride gas is introduced into a solution or slurry containing 2,6-dimethylphenol and a solvent and/or cocatalyst to saturate, and then 4-hydroxy-3,5- It is preferable to carry out the reaction by successively adding dimethylacetophenone. The amount of the acidic catalyst used is preferably in the range of 0.1 to 20.0 moles, and more preferably in the range of 0.5 to 10.0 moles per mole of 4-hydroxy-3,5-dimethylacetophenone.

Moreover, in the said reaction, you may use a cocatalyst in combination with an acidic catalyst. Specific examples thereof include thiols such as methyl mercaptan, ethyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan, mercaptoacetic acid, and β-mercaptopropionic acid. As the usage amount, 2 to 30 mol% is preferable, and 4 to 20 mol% is more preferable with respect to 4-hydroxy-3,5-dimethylacetophenone.

The reaction is usually conducted in the presence of a solvent. The solvent is not particularly limited as long as it does not inhibit the reaction, but examples include lower (C ₁ to _{C 4} ) aliphatic alcohols such as methanol, ethanol, 1-propanol and 2-propanol, and aromatic hydrocarbons such as toluene and xylene. , ethers such as tetrahydrofuran and dioxolane, saturated aliphatic hydrocarbons such as hexane, heptane and cyclohexane, and water. These solvents can be used alone or in combination. In addition, the amount of the solvent used is not particularly limited as long as it does not interfere with the reaction, but is usually used in the range of 1 to 100 parts by weight, preferably 5 to 50 parts by weight, based on 100 parts by weight of 2,6-dimethylphenol.

During the reaction, the method of adding raw materials, etc. is not particularly limited, but the remaining amount of 2,6-dimethylphenol and 4-hydroxyl are added to a solution containing a part of 2,6-dimethylphenol, an acidic catalyst, and, if necessary, a cocatalyst. The method of mixing the liquid mixture of -3,5-dimethylacetophenone is preferable from a viewpoint of reaction selectivity. In the case of the method of mixing, it is carried out in a range where the required mixing time is 0.5 to 5 hours. The reaction is performed so that the liquid after mixing is the amount of the above-mentioned raw materials used.

In the above reaction, water is produced by a dehydration condensation reaction between 4-hydroxy-3,5-dimethylacetophenone and 2,6-dimethylphenol. By carrying out the reaction under dehydration conditions that remove moisture in the reaction system, such as reaction product water and catalyst-containing water, the reaction proceeds faster than in the case of not dehydrating, the production of by-products is suppressed, and the target product can be obtained in a higher yield. desirable. The dehydration method is not particularly limited, but examples thereof include dehydration by adding a dehydrating agent, dehydration by reduced pressure, dehydration under normal pressure or reduced pressure according to the boiling point of the solvent, and the like.

＜Post-processing＞

The endpoint of the reaction can be confirmed by liquid chromatography or gas chromatography analysis. The point at which unreacted 4-hydroxy-3,5-dimethylacetophenone disappears or no increase in the target 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane is observed. It is preferable to make , the end point of the reaction.

A well-known method can be used suitably for obtaining a target object from the obtained reaction mixture. For example, crude neutralization is performed by adding an alkaline aqueous solution obtained by dissolving an alkaline compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, or potassium carbonate to the reaction mixture. Then, an acid such as phosphoric acid or hydrochloric acid is added to neutralize the pH to 4-8. After neutralization, the aqueous layer containing the neutralizing agent is separated and removed. Thereafter, after separating the aqueous layer, water is added and the operations of stirring, standing, and separating and removing the aqueous layer are performed a plurality of times to wash the oil layer. After sufficient washing, it is preferable to distill the washed oil layer to remove the solvent and 2,6-dimethylphenol.

<Method for producing crystals>

The crystals in the present invention are formed by dissolving 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane in an aromatic hydrocarbon solvent, cooling the solution to precipitate crystals, that is, crystals. You can get it. Specific examples of the aromatic hydrocarbon solvent include benzene, toluene, xylene, mesitylene and the like, and among these, toluene, xylene or mesitylene is preferable, toluene or xylene is more preferable, and toluene is particularly desirable.

The amount of aromatic hydrocarbon solvent used is preferably in the range of 250 to 1500 parts by weight, and preferably in the range of 300 to 1000 parts by weight, based on 100 parts by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane. More preferably, the range of 300 to 800 parts by weight is still more preferred, and the range of 300 to 600 parts by weight is particularly preferred.

As 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane used for crystallization, it is preferable to use one that has undergone the above-mentioned "post-treatment" step, and the preparation obtained in this way ( The content of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane in the powder is preferably 60% by weight or more, more preferably 70% by weight or more, and 75% by weight or more. It is more preferable, and it is especially preferable that it is 80% by weight or more.

The preparation of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane used for crystallization may contain 2,6-dimethylphenol used as a raw material, and the content is smaller. It is preferably in the range of 0 to 40% by weight, preferably in the range of 0 to 35% by weight, more preferably in the range of 0 to 30% by weight, particularly preferably in the range of 0 to 20% by weight.

The sum of the contents of this preparation with 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane, 2,6-dimethylphenol, and other components is 100% by weight.

As the crystallization conditions, the range of 30 to 120 ° C. is preferable for the crystallization temperature, the cooling rate is 1 to 10 ° C. per hour, preferably 3 to 7 ° C. per hour, and the holding time at the same temperature after crystal precipitation is 30 ° C. Minutes to 1 hour are preferable.

The precipitated crystals can be obtained by filtering by suction filtration or centrifugal filtration or the like to separate the crystals from the crystallization solvent. The temperature at this time is preferably 10 to 30°C, more preferably 20 to 25°C.

In addition, when drying the crystal obtained by filtration, it is preferable to carry out under reduced pressure, and the temperature at that time is preferably 50 to 190°C, more preferably 60 to 170°C.

<Crystal of the present invention>

The crystal of the present invention has an endothermic maximum temperature in the range of 195 to 225°C as determined by differential scanning calorimetry. The endothermic maximum temperature is preferably in the range of 200 to 220°C, more preferably in the range of 202 to 218°C, still more preferably in the range of 205 to 216°C, particularly preferably in the range of 207 to 214°C. do.

Further, the crystal of the present invention preferably has a loose bulk density in the range of 0.25 to 0.6 g/cm 3 . The lower limit of this loose bulk density is preferably 0.30 g/cm 3 . The upper limit of the loose bulk density is preferably 0.50 g/cm 3 , more preferably 0.40 g/cm 3 , and particularly preferably 0.35 g/cm 3 .

Further, in the powder X-ray diffraction peak pattern of the crystal of the present invention by Cu-Kα rays, the diffraction angles 2θ are 11.0±0.2°, 12.9±0.2°, 16.1±0.2°, 17.5±0.2° and 22.2±0.2°. It is preferably a crystal having a diffraction peak at .

The crystals of the present invention are useful as raw materials for polyphenylene ether, raw materials for epoxy resins, and raw materials for polycarbonate resins.

Example

The present invention will be specifically described below by examples, but the present invention is not limited to these examples.

The analysis method in the present invention is as follows.

<Analysis method>

1. Differential Scanning Calorimetry (DSC)

2.5 to 3.5 mg of the crystals were accurately weighed and sealed in an aluminum pan, and measured using a differential scanning calorimetry device (DSC7020 manufactured by Hitachi High-Tech Science Co., Ltd.) under the following operating conditions with aluminum oxide as a reference.

(Operation condition)

heating rate : 10℃/min

Measurement temperature range: 30 to 250°C

Measurement atmosphere: Nitrogen 50 mL/min

2. Loose bulk density

A crystal is quietly introduced into a measuring cylinder with a capacity of 5 mL so as not to create an air gap, and the specific scale X (mL) of the measuring cylinder and the weight W (g) of the crystal in the measuring cylinder at that time are measured, and W / X ( The value calculated by g/cm 3 ) was taken as the "loose bulk density" in the present invention.

3. Purity by high-performance liquid chromatography analysis

The area percentage of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane in the sample measured under the following equipment and conditions was taken as purity.

Apparatus: Shimadzu Corporation ProminenceUFLC (liquid chromatography)

Pump: LC-20AD

Column Oven: CTO-20A

Detector: SPD-20A

Column: HALO C18 (inner diameter 3 mm, length 75 mm)

Oven temperature: 50 degrees Celsius

Flow rate: 0.7 mL/min

Mobile phase: (A) 0.2% by volume acetic acid aqueous solution, (B) methanol

Gradient conditions: (B) volume % (time from start of analysis)

20%(0 min)→40%(10 min)→60%(20 min)→100%(30 min)→100%(35 min)

Sample injection amount: 7 μL

Detection wavelength: 280 nm

4. Powder X-ray diffraction (XRD) measurements

0.1 g of crystals of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane obtained in Example 2 were packed in the sample packing part of a glass test plate, and the measurement was performed with the following equipment and conditions.

Apparatus: MiniFlex600-C manufactured by Rigaku Co., Ltd.

X-ray source: CuKα

Scan width: 2θ/θ

Mode: Continuous

Measurement range: 2θ = 5 to 90°

Step: 0.02°

Speed measurement time: 10°/ min

Incidence slit: 0.25°

Light-receiving slit: 13.00 mm

Tube voltage: 40 kV

Tube current: 15 mA

<Example 1>

56.3 g (460.9 mmol) of 2,6-dimethylphenol and 20.8 g of methanol were placed in a 500 mL four-neck flask, the temperature of the solution was raised to 40 ° C. under a nitrogen atmosphere, and then hydrogen chloride gas was blown into the system until the system was saturated. . 8.4 g (25.2 mmol) of 21% sodium methyl mercaptan aqueous solution was added dropwise to this while stirring while maintaining the reaction temperature at 38 to 42 ° C. A solution in which 25.0 g (152.0 mmol) of oxy-3,5-dimethylacetophenone was dissolved at 80 ° C was added dropwise over 1 hour, and after the dropwise addition was completed, the mixture was stirred for 16 hours at a reaction temperature of 39 to 42 ° C while blowing hydrogen chloride gas. . After completion of the reaction, an aqueous sodium hydroxide solution and phosphoric acid were added to adjust the pH to 5.2, and then the aqueous layer was separated and removed. From the obtained oil layer, methanol and excess 2,6-dimethylphenol were removed by distillation under reduced pressure. The crude product, which is the residue after this distillation, contained 68% by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 28% by weight of 2,6-dimethylphenol.

30.0 g of toluene was added and dissolved at 60°C to 14.5 g of the crude product, which is the residue after distillation, and gradually cooled to 25°C at 5°C/hour, and precipitated crystals were filtered. The obtained crystals were heated up to 120°C under reduced pressure and dried to obtain 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane. The yield of 4-hydroxy-3,5-dimethylacetophenone was 16%, and the purity by high-performance liquid chromatography analysis was 90.5 area%.

The endothermic maximum temperature of the obtained crystals by differential scanning calorimetry was 208.5°C, and the loose bulk density was 0.315 g/cm 3 .

DSC data of the obtained crystals are shown in FIG. 1 .

<Comparative Example 1>

267.9 g (2192.3 mmol) of 2,6-dimethylphenol and 136.9 g of methanol were placed in a 2 L four-necked flask, the temperature of the solution was raised to 40 ° C. under a nitrogen atmosphere, and then hydrogen chloride gas was blown into the system until the system was saturated. . 36.0 g (103.2 mmol) of 21% sodium methyl mercaptan aqueous solution was added dropwise to this while stirring while maintaining the temperature of the reaction solution at 38 to 42 ° C. A solution in which 120.0 g (730.8 mmol) of oxy-3,5-dimethylacetophenone was dissolved at 80°C was added dropwise over 1 hour, and after the dropwise addition was completed, the mixture was stirred at a reaction temperature of 39 to 42°C for 16 hours while blowing hydrogen chloride gas. . After completion of the reaction, aqueous sodium hydroxide solution and phosphoric acid were added to adjust the pH to 5.2, and then the aqueous layer was separated and removed. From the obtained oil layer, methanol and excess 2,6-dimethylphenol were removed by distillation under reduced pressure. The crude product, which is the residue after this distillation, contained 31% by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 52% by weight of 2,6-dimethylphenol.

300.0 g of toluene was added and dissolved at 80°C to 412.9 g of the crude product, which is the residue after distillation, and gradually cooled to 25°C at 5°C/hour, and the precipitated solid was filtered. The obtained solid was heated up to 120°C under reduced pressure and dried to obtain a solid content containing 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane. The purity of the obtained solid by high-performance liquid chromatography analysis was a preparation of 67.0 area%. This formulation contained 80% by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 11% by weight of 2,6-dimethylphenol.

<Example 2>

To 133.3 g of the preparation obtained by filtration and drying in Comparative Example 1, 450 g of toluene was added and dissolved at 80°C, and the mixture was gradually cooled to 25°C at 5°C/hour, and the precipitated crystals were filtered. The obtained crystals were heated to 120°C under reduced pressure and dried to obtain 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane. The yield relative to the amount of 4-hydroxy-3,5-dimethylacetophenone in Comparative Example 1 was 35.1%, and the purity by high-performance liquid chromatography analysis was 96.4%.

The endothermic maximum temperature of the obtained crystals by differential scanning calorimetry was 211.1°C.

DSC data of the obtained crystals are shown in FIG. 2 .

An XRD measurement chart of the obtained crystal is shown in FIG. 3 . Among the diffraction peaks, the diffraction angle 2θ (°) and relative intensity of the peak having a relative intensity of 0.2 or more based on the peak with the strongest intensity are shown in Table 1 below.

<Comparative Example 2>

55.0 g (450.1 mmol) of 2,6-dimethylphenol and 24.8 g of methanol were placed in a 1 L four-necked flask, the liquid temperature was raised to 40 ° C. under a nitrogen atmosphere, and then hydrogen chloride gas was blown into the system until the system was saturated. . While maintaining the reaction solution temperature at 38 to 42°C, 9.0 g (44.5 mmol) of lauryl mercaptan was added dropwise thereto while stirring, and then 110.0 g (900.2 mmol) of 2,6-dimethylphenol and 4-hydroxy-3 A solution in which 25.0 g (152.0 mmol) of 5-dimethylacetophenone was dissolved at 80°C was added dropwise over 1 hour, and after the dropwise addition was completed, the mixture was stirred at a reaction temperature of 39 to 42°C for 16 hours while blowing hydrogen chloride gas. After completion of the reaction, aqueous sodium hydroxide solution and phosphoric acid were added to adjust the pH to 5.2, and then the aqueous layer was separated and removed. The obtained oil layer was divided into two.

Methanol and 2,6-dimethylphenol contained in one oil layer divided into two were removed by distillation under reduced pressure. 7.9 g of the crude product, which is the residue after distillation, contained 37.2% by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 44.8% by weight of 2,6-dimethylphenol. When a mixture of methyl isobutyl ketone and toluene (weight ratio 4:1) was added in an amount of 50% by weight based on the weight of the obtained distillation residue, the entire amount was dissolved, and then crystals were formed even when left still at 25 ° C. for 20 hours It didn't work.

<Comparative Example 3>

With respect to the other oil layer divided into two in Comparative Example 2, methanol and 2,6-dimethylphenol contained therein were removed by distillation under reduced pressure. 9.9 g of the crude product, which is the residue after distillation, contained 38.9% by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane and 42.1% by weight of 2,6-dimethylphenol. When dichloromethane was added in an amount of 4 mL of dichloromethane with respect to the weight of 1 g of the obtained distillation residue, the entire amount was dissolved, and no crystals were formed even after standing at 25°C for 20 hours.

<Solubility in organic solvents>

The solubility (g) of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane in 100 g of solvent was measured for the solvents described in the table. The results are shown in Table 2. In addition, "-" in a table|surface means unmeasured.

From the results shown in Table 2, compared to the toluene used in Examples 1 and 2, methanol, acetone, and methyl isobutyl ketone have a higher concentration of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane It turned out that the solubility is high and unpreferable for crystallization operation.

On the other hand, the toluene used in Examples 1 and 2 had a sufficient difference in solubility of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane depending on the temperature, and at room temperature (25°C) Loss of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane to the filtrate when the crystals are separated by filtration after the crystallization operation. It became clear what was desirable. In addition, it was confirmed that xylene, like toluene, is suitable as a solvent for crystallizing 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane.

Claims (4)

A crystal of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl)ethane having an endothermic maximum temperature in the range of 195 to 225°C as determined by differential scanning calorimetry. According to claim 1,
A crystal with a loose bulk density in the range of 0.25 to 0.6 g/cm 3 . According to claim 1 or 2,
Crystals having diffraction peaks at diffraction angles 2θ of 11.0±0.2°, 12.9±0.2°, 16.1±0.2°, 17.5±0.2° and 22.2±0.2° in the powder X-ray diffraction peak pattern by Cu-Kα rays . A solution containing 100 parts by weight of 1,1,1-tris(4-hydroxy-3,5-dimethylphenyl) ethane and 250 to 1500 parts by weight of an aromatic hydrocarbon solvent is cooled to precipitate crystals. A method for producing the crystal according to any one of claims 1 to 3.