JP2985476B2 - Method for producing spherical 2,6-di-tert-butyl-4-methylphenol - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing spherical 2,6-ditert-butyl-4-methylphenol.

[0002]

2. Description of the Related Art 2,6-Di-tert-butyl-4-methylphenol (hereinafter abbreviated as BHT) is a compound well known as an antioxidant, It is also known that it is produced by methods such as dibutylation of cresol and methylation of 2,6-ditertiary butylphenol, and when recrystallized from an organic solvent, crystallizes as square crystals such as tetragonal and flat tetragonal. Have been.

[0003] BHT is commercially available in the form of powder, flakes, granules and the like, but both powder and flakes are poor in fluidity and are hardly subject to automatic weighing and automatic supply systems. . In addition, although granular products can be subject to the automatic measurement and automatic supply system, BHT crystals are angular crystals as described above and have the property of being brittle against external forces such as mechanical wear, load, and vibration. Therefore, there is a disadvantage that fine powders are easily generated, and these fine powders trigger a problem such as blocking.

[0004] On the other hand, attempts have been made to make the product form spherical in order to enhance fluidity and prevent generation of fine powder. For example, a method for producing spherical bisphenols by melting an object, dispersing it in water, and then cooling and solidifying the same (Japanese Patent Publication No. 58-20992), melting the object in the presence of a surfactant, Is dispersed in water and then cooled and solidified to produce a spherical organic peroxide (JP-A-51-97873). However, these methods were applied to BHT, but spherical products were not obtained.

[0005]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in order to produce spherical BHT products, and as a result, have identified BHT dissolved in a mixture of water and an organic solvent immiscible with water. The present invention was found to be easy to produce by crystallization under the above stirring conditions, and further various studies were carried out to complete the present invention.

That is, according to the present invention, after dissolving BHT in a mixture of water and an organic solvent immiscible with water, the following formula (1) is obtained: P = N _p · ρ · n ³ · d ⁵ / g _C V (1) (where N _p , ρ, n, d, g _C , and V represent the power number, liquid specific gravity, stirring number, stirring blade diameter, gravitational acceleration, and liquid volume, respectively). The present invention provides a method for producing a spherical BHT, characterized in that crystallization is carried out from a two-layer mixture of an organic layer and an aqueous layer under stirring conditions with a power P in the range of 12 to 120 Kg / s · m ^2. .

Hereinafter, the present invention will be described in detail. Examples of the water-immiscible organic solvent used in the present invention include, for example, hexane, cyclohexane, pentane, octane, saturated hydrocarbons such as isooctane, cyclohexene,
Unsaturated hydrocarbons such as tetramethylethylene, 2-methyl-2-pentene, 2-methyl-3-pentene and 3-methyl-2-pentene; aromatic hydrocarbons such as benzene, toluene and chlorobenzene; dichloromethane and dichloroethane , Chloroform, halogenated hydrocarbons such as carbon tetrachloride, diethyl ether, dipropyl ether, dibutyl ether, ethyl propyl ether, ethyl butyl ether, ethers such as propyl butyl ether, butanol, isobutanol, pentanol,

C 4-8 alcohols such as isopentanol, hexanol and 2-ethylhexanol, methyl acetate, ethyl acetate, propyl acetate, isopropyl acetate, butyl acetate, isobutyl acetate, amyl acetate, isoamyl acetate, propionic acid Examples thereof include carboxylic acid esters such as methyl and ethyl propionate, ketones having 3 to 9 carbon atoms such as methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and dibutyl ketone, petroleum ether, petroleum benzine, and ligroin. These can be used as a mixture.

The amount used is usually 1/1
It is 30 to 1/2 weight times, preferably 1/20 to 1/5 weight times.

The amount of water used for BHT is usually 1/4.
It is 10 to 10 times by weight, preferably 1/3 to 3 times by weight.

The present invention can also be carried out in the presence of water, an organic solvent immiscible with water, and an organic solvent miscible with water. In this case, the purification ability is improved, and BHT with higher purity can be obtained. Examples of such a solvent include alcohols having 1 to 3 carbon atoms such as methanol, ethanol, propanol and isopropanol, and acetone. The amount used may be any range as long as the system maintains a two-layer system of an aqueous layer and an organic layer during crystallization.
It is less than twice the water used.

According to the present invention, the dissolved BHT is converted to a power of 12 to
The stirring conditions of 120 Kg / s · m ^2, a two-layer system a mixture of organic and aqueous phases, but is characterized in that the allowed to crystallization, sufficient for agitation of less than 12 Kg / s · m ² spherical products capable of satisfying can not be obtained, and because there tends to be when it exceeds 120 Kg / s · m ² and fine spherical, be crystallized under stirring conditions of the power 12~120Kg / s · m ² Appropriate. Preferably 15 to 110 Kg / s
M ² , more preferably 25 to 100 Kg / s · m ² .

The crystallization is usually carried out at a temperature lower than the melting point of BHT, and the crystallization time depends on the type and amount of the solvent used and the stirring efficiency, but usually 4 hours or more is sufficient.
It is not necessary to lengthen the crystallization time unnecessarily, and it is preferably 6 to 20 hours. At the time of crystallization, it is effective to add a seed crystal, and in this case, particles having a uniform particle size are obtained.

The resulting spherical crystals are taken out of the solvent by, for example, filtration or the like, and then dried to obtain a spherical BHT product.

[0015]

According to the present invention, spherical BHT can be easily obtained. Further, the spherical BHT obtained by the present invention is:
It has excellent fluidity, has extremely low generation of fine powder, and has a property of hardly blocking, and can sufficiently cope with automatic continuous industrial operation.

[0016]

The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto. The compression ratio is the specific gravity when particles are gently poured into a 100 ml measuring cylinder (A: loose apparent specific gravity)
And the specific gravity (B: solidified apparent specific gravity) when the volume did not decrease further after the measuring cylinder was dropped from a height of 10 cm. Compression ratio = 100 (BA)
/ B

Example 1 A three-blade anchor stirrer with a blade diameter of 0.087 m was installed.
l in a l separable flask (0.13 m ID)
g, 90 g of ligroin and 610 g of water were added and heated to 60 ° C. to completely dissolve the crystals. Then, with stirring at 450 rpm
(Stirring power 57 Kg / s · m ²⁾ which continue to cool, at 6 hours was added as a seed crystal to 0.1g of micro BHT crystals at 52 ° C. 20
Cooled to ° C. After filtering the formed crystals, 500 g of 95%
After washing with methanol and drying, 631 g of spherical BHT was obtained. This one is under 1680 micron sieve
It contained 95% of a particle size on a 500 micron sieve, had a compressibility of 2.4% and an angle of repose of 28 degrees.

Example 2 In Example 1, stirring was performed at 550 rpm (stirring power: 104 Kg / s).
・ M ² ) was performed in accordance with Example 1, except for 629.
g of spherical BHT was obtained. It contained 92.1% of a particle size below the 1680 micron sieve to above the 500 micron sieve, had a compressibility of 3.1% and an angle of repose of 28 degrees.

Example 3 In Example 1, stirring was performed at 350 rpm (stirring power: 27 kg / s · m).
^The procedure was performed in the same manner as in Example 1, except that the cooling was performed in 7 hours, to obtain 630 g of spherical BHT. This one, 16
90% under 80 micron sieve to 500 micron sieve
It contained 3.2% compression and a 28 degree angle of repose.

Example 4 In Example 1, stirring was performed at 300 rpm (stirring power: 17 kg / s · m).
² ) The procedure was performed in the same manner as in Example 1 except that cooling was performed for 9 hours to obtain 620 g of spherical BHT. This one, 16
95% of the particle size below 80 micron sieve to 500 micron sieve
The compression ratio was 3.9% and the angle of repose was 30 degrees.

Comparative Example 1 In Example 4, stirring was performed at 250 rpm (stirring power 10 Kg / s).
When - except that a m ²⁾ was carried out in conformity with example 4,
630 g of tetragonal BHT were obtained. This is 1680
It contained 99% of particles below the micron sieve to above the 500 micron sieve, with a compressibility of 4.7% and an angle of repose of 38 degrees.

Comparative Example 2 In Example 1, stirring was performed at 600 rpm (stirring power: 135 Kg).
/ s · m ² ), and 616 g of spherical BHT was obtained. This is 1680
It contained 91% of particles below the micron sieve to above the 500 micron sieve, with a compressibility of 5.1% and an angle of repose of 37 degrees.

Comparative Example 3 The procedure of Example 1 was repeated, except that 700 g of 95% methanol was used in place of water and ligroin (power of stirring 47 kg / s · m ² ). Of BHT was obtained. The tetragonal crystal was in a crushed crystal form (flat tetragonal form) and contained a large amount of fine powder. This is 1680
It contained 80% below micron sieve to above 500 micron sieve, with a compressibility of 8.5% and an angle of repose of 42 degrees.

Example 5 The procedure of Example 1 was repeated, except that 90 g of cyclohexane was used instead of ligroin, and the mixture was cooled in 8 hours. The procedure was the same as in Example 1 (stirring power: 57.3 kg / s · m ² ), and 630 g. Spherical B
HT was obtained. It contains 95% of the particle size below 1680 micron sieve to 500 micron sieve and has a compressibility of 2.
At 1%, the angle of repose was 27 degrees.

Example 6 The procedure of Example 1 was repeated, except that 90 g of tetramethylethylene was used instead of ligroin.
(Agitation power: 57 kg / s · m ² ), 602 g of spherical BHT was obtained. It contained 94% of the particle size below 1680 micron sieve to 500 micron sieve, had a compressibility of 2.8% and an angle of repose of 27 degrees.

Example 7 The procedure of Example 1 was repeated, except that 700 g of 95% pure crude BHT was used.
I got Purity was 99.95%. This is 1680
95.9% of the particle size below the micron sieve to 500 micron sieve
It had a compression ratio of 3.7% and an angle of repose of 28 degrees.

Example 8 The procedure of Example 7 was repeated, except that 90 g of n-butanol was used in place of ligroin (57 kg / s · m ^{2 of} stirring power) to obtain 600 g of spherical BHT. Was. Purity was 99.97%. This one is under 1680 micron sieve
It contained 86% of a particle size on a 500 micron sieve, had a compressibility of 3.8% and an angle of repose of 29 degrees.

Example 9 The procedure of Example 7 was repeated, except that 90 g of cyclohexane was used instead of ligroin (agitating power: 57 kg / s · m ² ) to obtain 595 g of spherical BHT. Purity was 99.94%. This one is under 1680 micron sieve
It contained 95% of a particle size on a 500 micron sieve, had a compressibility of 2.0% and an angle of repose of 28 degrees.

Example 10 In Example 7, ethyl acetate 90 was used instead of ligroin.
g was carried out according to Example 7 except that
57 kg / s · m ² ) and 590 g of spherical BHT were obtained. Purity is 99.
97%. This one is under 1680 micron sieve ~ 500
It contained 99% of a particle size on a micron sieve, had a compressibility of 2.1% and an angle of repose of 29 degrees.

Example 11 The procedure of Example 1 was repeated, except that crude BHT having a purity of 95% was used, 70 g of ligroin, 315 g of water, and 315 g of methanol were used (stirring power: 52 kg / s · m ² ). The operation yielded 590 g of spherical BHT. Purity was 99.97%. It contains 97% of the particle size below 1680 micron sieve to 500 micron sieve, with a compressibility of 3.2%,
The angle of repose was 27 degrees.

Example 12 Example 11 was carried out in the same manner as in Example 11, except that 70 g of 1,2-dichloroethane was used instead of ligroin.
A stirring power of 52 kg / s · m ² ) and 590 g of spherical BHT were obtained.
Purity was 99.97%. It contained 97% of the particle size below 1680 micron sieve to 500 micron sieve, had a compressibility of 1.1% and a repose angle of 26 degrees.

Example 13 In Example 11, cyclohexane was used instead of ligroin.
The procedure was carried out in the same manner as in Example 11 except that the mixture was cooled in 8 hours using 70 g (stirring power: 52 kg / s · m ² ), and 585 g of spherical B
HT was obtained. Purity was 99.98%. This one is
It contained 88% of what was below the 1680 micron sieve to above the 500 micron sieve, had a compression ratio of 1.4% and an angle of repose of 27 degrees.

Example 14 In Example 11, a Faudler blade stirrer (blade diameter 0.087 m) was used instead of the anchor type stirrer, and the rotation speed was changed to 350 rpm (stirring power 46 Kg / s · m ² ). The operation was carried out according to Example 11 to obtain 580 g of spherical BHT. Purity was 99.97%. It contains 92.1% of particles having a particle size of 1680 micron sieve to 500 micron sieve, and has a compressibility of 3.7
%, Angle of repose was 30 degrees.

Example 15 The procedure of Example 11 was repeated, except that a two-blade anchor stirrer (with a blade diameter of 0.087 m) was used instead of the three-blade anchor stirrer.
This was carried out in accordance with 11 to obtain 589 g of spherical BHT. Purity
99.97%. This is a 1680 micron sieve ~ 50
It contained 94% of a particle size on a 0 micron sieve, had a compressibility of 2.4% and an angle of repose of 29 degrees.

Example 16 The procedure of Example 11 was repeated, except that 70 g of dibutyl ether was used instead of ligroin (stirring power: 52 Kg / s · m ² ), to obtain 585 g of spherical BHT. Obtained.
Purity was 99.97%. It contained 93% of the particle size below 1680 micron sieve to 500 micron sieve, had a compressibility of 2.1% and a repose angle of 29 degrees.

Example 17 In Example 11, cyclohexane was used instead of ligroin.
70 g was replaced with methanol, using 315 g of acetone, seeding at 25 ° C., and cooling was performed up to 5 ° C. in 6 hours according to Example 11, except that stirring power was 52 Kg / s · m. ² ), 55
0 g of spherical BHT was obtained. Purity was 99.97%.
It contained 87% of the particle size below 1680 micron sieve to 500 micron sieve, had a compressibility of 3.5% and an angle of repose of 30 degrees.

Example 18 The procedure of Example 7 was repeated, except that the cooling was performed up to 18 ° C., to obtain 588 g of spherical BHT.
Purity was 99.94%. It contained 96% of the particle size below 1680 micron sieve to 500 micron sieve, had a compressibility of 3.8% and an angle of repose of 28 degrees.

Reference Example 1 <Crush resistance test> BHT20 obtained in Examples and Comparative Examples was placed in a cylinder having a diameter of 5 cm.
g and a load of 8 kg / cm ² was applied 5 times for about 3 seconds every 5 seconds.
It was shown to.

Reference Example 2 <Blocking resistance test> Into a cylinder having a diameter of 5 cm, 15 g of BHT prepared so that the sieve under a 150-micron screen was 5% was placed under a load of 67 g / cm ² at 35 to 37 ° C. After standing for a period of days, the minimum load at which the generated solids could be broken was determined and is shown in Table 1. However, the sample of Comparative Example 3 was used without any preparation and tested. The 150-micron sieve used in the preparation was fine powder (135 g) obtained by crushing the BHT (300 g) obtained in Comparative Example 3 in a mortar and then sieving. Table 1 No. Increase (%) Minimum load (Kg / cm ² ) Example 1 1.2 0.4 Example 2 1.2 0.5 Example 3 1.2 0.6 Example 4 1.2 0.5 Example 5 1.1 0.4 Example 6 1.2 0.6 Example 7 1.6 0.8 Example 8 1.1 0.4 Example 9 1.0 0.3 Example 10 1.1 0.4 Example 11 1.3 0.7 Example 12 1.0 0.2 Example 13 1.0 0.8 Example 14 1.1 0.5 Example 15 1.4 0.5 Example 16 1.3 0.4 Example 17 1.9 0.8 Example 18 1.9 0.8 Comparative Example 1 3.6 1.6 Comparative Example 2 3.0 1.3 Comparative Example 3 8.2 3.2

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) C07C 37/84 C07C 39/06 C07C 39/00

Claims (4)

(57) [Claims] After dissolving 2,6-di-tert-butyl-4-methylphenol in a mixture of water and an organic solvent immiscible with water, the compound of the formula (1) P = N _p · ρ · n ³ · d ⁵ / g _C · V (1) (where N _p , ρ, n, d, g _C , and V are the power number, liquid specific gravity, stirring number, stirring blade diameter, gravitational acceleration, The sphere is characterized by being crystallized from a two-layer mixture of an organic layer and an aqueous layer under a stirring condition in which a power P defined by the following formula is in the range of 12 to 120 Kg / s · m ^2. A method for producing 2,6-di-tert-butyl-4-methylphenol. 2. An organic solvent which is immiscible with water includes aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, carboxylic esters, alcohols having 4 to 8 carbon atoms, and alcohols having 4 to 8 carbon atoms.
The method according to claim 1, wherein the solvent is at least one solvent selected from the group consisting of ketones and ethers. 3. The process according to claim 1, wherein the method is carried out in the presence of an organic solvent immiscible in both water and an organic solvent immiscible with water. 4. An organic solvent which is miscible with water or an organic solvent immiscible with water is at least one solvent selected from alcohols having 1 to 3 carbon atoms and acetone. Item 4. The production method according to Item 3.