JPH06128195A - Production of tetrakis(3-@(3754/24)3,5-di-tertiary-butyl-4-hydroxyphenyl)propionyloxymethyl)methane - Google Patents

Abstract

PURPOSE:To produce tetrakis [3-(3,5-di-tert.butyl-4-hydroxyphenyl) propionyloxymethyl]methane excellent in fluidity and having a beta-crystal structure as large crystal particles reduced in occurrence of 'dust. CONSTITUTION:This production of tetrakis[3-(3,5-di-tert.butyl-4-hydroxyphenyl) propionyloxymethyl]methane having a beta crystal structure is characterized by using a mixed solvent containing 70-95wt.% lower alcohol, 1-20wt.% water and 0.5-10wt.% saturated aliphatic hydrocarbon solvent as a solvent in crystallizing.

Description

Detailed Description of the Invention

[0001]

The present invention relates to tetrakis [3- (3,3
5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane (hereinafter, also referred to as AO-60), more specifically, a mixed solvent having a specific composition when AO-60 is crystallized. Is used to produce AO-60 having a β crystal structure as large crystal particles having excellent fluidity and little dust generation.

[0002]

2. Description of the Related Art AO-
60 is a compound widely used as an antioxidant for synthetic polymer materials such as polyolefin, and 3- (3
It is known to be produced by transesterifying a lower alkyl ester such as a methyl ester of 5-di-tert-butyl-4-hydroxyphenyl) propionic acid with pentaerythritol. It is known that AO-60 produced by such a method has four types of crystal forms, α crystal, β crystal, γ crystal and δ crystal,
These are distinguished by measurement of diffraction X-ray, melting point, infrared absorption spectrum and the like.

Of these crystal forms, α crystal has a high melting point,
Not only inferior in compatibility when compounded into a synthetic resin with a low processing temperature, but also easily impregnated with impurities during crystallization, there is a drawback that the purity and hue of the product are inferior, γ crystal has a low melting point,
It has the drawback that it melts during storage or transportation and tends to agglomerate.Although δ-crystal is excellent in fluidity, the reaction is carried out in the presence of specific impurities, and at the time of crystallization, alcohols and molecular adducts are used. Since it cannot be produced unless it is recrystallized after the formation of the product, the product yield is low, and the number of steps is large, which is not economical.

On the other hand, the β crystal has no quality problem,
In addition, since there is no need to add impurities in the manufacturing method, there is an advantage that the yield is high and the number of steps is small. Most of the AO-60 currently on the market is β crystal, but the commercially available AO-60 No. 60 was in the form of fine powder, had a low bulk specific gravity and poor fluidity, and had the drawbacks of dust being easily scattered during handling, and had problems in workability, meterability, and work environment.

For this reason, various studies have been carried out on a method of obtaining β crystals as coarse particles. However, β crystals are relatively unstable as a crystal form, and α crystals are mixed in during crystallization, or crystallization occurs. After holding the slurry even after the
Since the crystal structure changes to crystals, it is difficult to industrially stably produce β crystals as coarse particles.

For example, Japanese Patent Application Laid-Open No. 62-258343 proposes a method of obtaining independent particle crystals by crystallizing AO-60 containing impurities in an amount of 5% by weight or more with hydrous alcohol. However, in this method, not only the particle size of the particles obtained is still small, but also the strength of the particles is insufficient, and there is a drawback that the particles are pulverized during drying or transportation, or conversely aggregate. In addition, JP-A-2-
Japanese Patent No. 49752 proposes a method in which a reaction mixture of AO-60 is dissolved in alcohol, mixed with cooled hydrous alcohol, and water is added to produce β crystal as a crystal having a large bulk specific gravity. However, this method not only requires a two-step operation of once dissolving in a solvent and then pouring it into a cooled solvent, but also has a drawback that the particle size of the obtained particles is still small, which is practically satisfactory. It wasn't possible. Further, Japanese Patent Application Laid-Open No. 2-72139 proposes a method of crystallization using an aliphatic hydrocarbon solvent, but the obtained particles have a large repose angle and are intended to improve powder characteristics. Was not happy.

Further, JP-A-2-235848 discloses a method in which an aliphatic hydrocarbon solvent is used for crystallization to obtain independent particle-shaped crystals having an α-crystal structure.
No. 37 discloses a method of crystallizing using a mixed solvent of alcohol and water to obtain a particulate crystal having an α-crystal structure, and Japanese Patent Laid-Open No. 3-11038 discloses alcohol and aliphatic hydrocarbons. Although a method for producing AO-60 having an α-crystal structure by pouring into a mixed solvent of alcohol and water and crystallization after dissolution in a mixed solvent is proposed, AO-60 obtained by these methods is proposed. Has a crystal form other than β crystal, and it is far from solving the above-mentioned problems.

[0008]

In view of the above situation, the present inventors have earnestly studied to find a method for stably producing AO-60 having a β crystal structure as coarse particles having excellent fluidity. As a result, it was found that AO-60 having a β-crystal structure having a large particle size and a large particle strength can be stably produced by crystallization using a mixed solvent having a specific composition. The invention was reached.

That is, according to the present invention, tetrakis [3- (3,3
5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is crystallized, the solvent is 70-95% by weight of a lower alcohol, 1-20% by weight of water, and 0.5% of a saturated aliphatic hydrocarbon solvent. Provided is a method for producing tetrakis [3- (3,5-ditert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane having a β crystal structure, which comprises using a mixed solvent containing 10 to 10% by weight. To do.

Hereinafter, the manufacturing method of the present invention having the above-mentioned gist will be described in more detail.

Tetrakis [3- produced by the present invention
(3,5-Di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is a lower alkyl ester of 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid, such as methyl, Ethyl, propyl, butyl ester, etc. and pentaerythritol,
It is produced by carrying out a transesterification reaction in a solvent as the case requires. In the present invention, the reaction mixture in which the transesterification reaction is completed, the solvent used from the reaction mixture and / or the unreacted 3- ( 3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid lower alkyl ester partially or completely distilled off,
Alternatively, any one having a crystal structure other than the β crystal crystallized from the reaction mixture can be used. Further, in the reaction mixture subjected to crystallization according to the method of the present invention,
Usually, in addition to the target compound, unreacted lower alkyl ester of 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionic acid and a triester compound in which the reaction is not completed, that is, hydroxymethyl-tris [3- (3
5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is contained, and the desired product is tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl]. A methane content of 70% by weight or more can be used, and it is particularly effective when a methane content of 80% by weight or more is used.

In the method of the present invention, the lower alcohol used as the main solvent is methanol, ethanol, propanol, isopropanol, butanol, isobutanol, secondary butanol or the like having 1 to 4 carbon atoms.
Alcohols and mixed alcohols of these,
In particular, it is preferable to use methanol or a mixed alcohol mainly containing methanol.

The proportion of this lower alcohol in the crystallization solvent is 70 to 95% by weight, and particularly preferably 75 to 90% by weight. When the proportion of the lower alcohol is less than 70% by weight or more than 95% by weight, crystal forms other than β crystal are likely to be formed.

The ratio of water used in the crystallization solvent is 1-2.
0% by weight, especially 5 to 15% by weight is preferred. If the proportion of water is less than 1% by weight, the yield of crystallization is poor, and only poor powder properties are obtained, and if it exceeds 20% by weight, the crystallization temperature becomes high. It is difficult to obtain the target product stably. Also, in the method of the present invention, water may be added in the whole amount when the reaction mixture of AO-60 is dissolved in the crystallization solvent, but in order to accelerate the dissolution of the reaction mixture of AO-60 in the solvent, May be anhydrous or a solvent containing a small amount of water may be used, and the solvent may be added at a predetermined ratio after dissolution.

The saturated aliphatic hydrocarbon solvent has 6 carbon atoms.
Preferably 12 to 12, and n-hexane, n-heptane, n-octane, isooctane, n-nonane, isononane, n-decane, isodecane, n-undecane, isoundecane, n-dodecane, isododecane and the like,
Alternatively, they can be used as a mixture, and as a mixture,
Commercially available aliphatic hydrocarbon solvents such as Exxon Chemical's Isopar and Idemitsu Petrochemical's IP solvent can be used.

The proportion of the saturated aliphatic hydrocarbon in the crystallization solvent is preferably 0.5 to 10% by weight, more preferably 2 to 8% by weight, and if less than 0.5% by weight, the obtained crystal powder is obtained. Not only the characteristics are inferior, but also stable production of β crystal is difficult, and other crystal forms such as α crystal are often mixed. Also, if it is used in excess of 10% by weight, the purification effect is poor. As a result, the purity and hue of the obtained product deteriorate.

Further, in the method of the present invention, AO-6
It is preferable to carry out crystallization after deactivating the catalyst used in the production of O. As the catalyst, organic tin compounds such as dibutyltin oxide, alkali metal alkoxides such as sodium, potassium and lithium or alkali metal amides, titanium alkoxides such as tetraisopropyl titanate and the like are used, and therefore, formic acid, acetic acid and propion are usually used. The catalyst can be deactivated by a carboxylic acid such as acid or octylic acid or an inorganic acid. In order to prevent hydrolysis or coloration of AO-60 due to the residual of excess acidic substances, the reaction mixture contains butylamine, octylamine, monoethanolamine, diethylamine, dibutylamine, diethanolamine, diisopropanolamine, piperazine, morpholine, methyl. It is also possible to add organic or inorganic amine compounds such as diethanolamine, stearyldiethanolamine, triethylamine, tributylamine, triethanolamine, triisopropanolamine, ethylenediamine, tetraethanolethylenediamine, hexanediamine, ammonia, hydrazine and dimethylhydrazine.

AO-60 having a β crystal structure produced by the method of the present invention has a large particle size and bulk specific gravity and is excellent in fluidity, and since it has few fine crystals, it does not easily scatter dust during operation. In addition, since the crystal has a high strength, it has a feature that the crystal does not break or aggregate during drying, transportation, or work.

[0019]

EXAMPLES The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.

(Example 1) 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propion was placed in a 4-liter flask having a capacity of 1 liter equipped with a stirrer, a reflux condenser, a thermometer and a nitrogen introducing tube. 463 g of methyl acidate and 49 g of pentaerythritol were taken and heated to 100 ° C. While stirring, 0.4 g of lithium amide and 16 g of tetralin were added, and the mixture was stirred for 1 hour under the conditions of 30 mmHg and 130 to 140 ° C. while distilling off the produced methanol, and then 5 to 5.
The mixture was stirred under the conditions of 10 mmHg and 150 to 160 ° C. for 5 hours, a small amount of produced methanol was distilled off, and finally tetralin was distilled off together with a part of the methyl ester used in excess to complete the reaction. The reaction mixture was cooled to 110 ° C., 2 g of glacial acetic acid was added to neutralize the catalyst, and the composition of the reaction mixture obtained was 87.4% by weight of the target AO-60.
Unreacted methyl ester 9.4% by weight, other 3.2
% By weight.

50 g of the obtained reaction mixture was added to 120 to 12
Melt by heating to 5 ° C, then cool to 110 to 115 ° C and mix methanol / water / aliphatic hydrocarbon (IP1620: manufactured by Idemitsu Petrochemical) = 92.0 / 5.0 / 3.0 (weight ratio). 102 g of the solvent was added and dissolved. A seed crystal was added at 45 to 50 ° C. and the mixture was cooled with stirring. When the temperature reached 25 ° C., 8.0 g of water was added, and then the mixture was cooled to 20 ° C.

The produced crystals were filtered, washed with 12% hydrous methanol and dried under reduced pressure to obtain 42.9 g of white crystalline product. As a result of analyzing the product by liquid chromatography, the purity of the target AO-60 was 98.7.
%, And the yield as AO-60 was 96.9%.

The product obtained has a melting point of 114-11.
It was 6 ° C., and as a result of X-ray (Cu-Kα) diffraction, the diffraction angle was 2
Since it has five sharp peaks in the range of θ = 5 to 10.5 degrees, it was confirmed to be β crystal.

Further, the obtained product was measured for apparent specific gravity, angle of repose and particle size distribution before and after shaking for 7 hours with a shaking stirrer.

Example 2 The same as Example 1 except that 110 g of a mixed solvent of methanol / water / aliphatic hydrocarbon = 85.3 / 111.9 / 2.8 (weight ratio) was used and water was not added. Crystallization was carried out by the above procedure, and the obtained crystals were measured for purity, yield, crystal form, apparent specific gravity, angle of repose and particle size distribution.

Example 3 The same as Example 1 except that 110 g of a mixed solvent of methanol / water / aliphatic hydrocarbon = 92.0 / 5.0 / 3.0 (weight ratio) was used and water was not added. Crystallization was carried out by the above procedure, and the obtained crystals were measured for purity, yield, crystal form, apparent specific gravity, angle of repose and particle size distribution.

Example 4 Example 1 was repeated except that 102 g of a mixed solvent of methanol / water / aliphatic hydrocarbon = 90.0 / 5.0 / 5.0 (weight ratio) was used and 8 g of water was added. Crystallization was performed by the same operation, and the obtained crystal was measured for purity, yield, crystal form, apparent specific gravity, angle of repose, and particle size distribution.

(Example 5) Crystallization was performed by the same operation as in Example 1 except that methanol was used as the crystallization solvent instead of ethanol, and the obtained crystals were purified, yielded, crystal form, apparent specific gravity, and repose. The corners and particle size distribution were measured.

Comparative Example 1 Methanol / water = 95.0 /
Crystallization was performed by the same operation as in Example 1 except that 102 g of the mixed solvent of 5.0 was used and 8.0 g of water was added, and the obtained crystal was purified, yield, crystal form, apparent specific gravity,
The angle of repose and the particle size distribution were measured.

Comparative Example 2 50 g of the reaction mixture obtained in Example 1 was heated and melted at 120 to 125 ° C., and then 11
Cool to 0-115 ° C and methanol / water = 95.0 /
110 g of a mixed solvent of 5.0 (weight ratio) was added and dissolved. When cooled thereafter, crystals were precipitated at around 55 ° C, so the mixture was cooled to 20 ° C with stirring. The result of DSC analysis of the obtained crystal showed two endothermic peaks at 122 ° C. and 114 ° C., and from the area ratio, 31:69 of α crystal and β crystal were observed.
It was shown to be a mixture of The purity, yield, apparent specific gravity, angle of repose, and particle size distribution of the obtained crystals were measured.

The results of Examples 1 to 5 and Comparative Examples 1 and 2 are summarized in Table 1 below.

[0032]

[Table 1]

(Example 6) α crystals and β obtained in Comparative Example 2
30 g of the mixed crystals was heated and melted at 125 to 130 ° C., then cooled to 110 to 115 ° C., and methanol / water / isooctane = 90.0 / 5.0 / 5.0 (weight ratio).
60 g of the mixed solvent of was added and dissolved. Seed crystals were added at 45 to 50 ° C and cooled with stirring. When the temperature reached 25 ° C, 5.0 g of water was added, and then cooled to 20 ° C.

The produced crystals were filtered, washed with 12% water-containing methanol and dried under reduced pressure to obtain 28.6 g of a white crystalline product. As a result of analyzing the product by liquid chromatography, the purity of the target AO-60 was 99.2.
%, And the yield as AO-60 was 97.7%.

The product obtained has a melting point of 114-11.
It was 6 ° C., and as a result of X-ray (Cu-Kα) diffraction, the diffraction angle was 2
Since it has five sharp peaks in the range of θ = 5 to 10.5 degrees, it was confirmed to be β crystal.

Further, the apparent specific gravity of the obtained product was 0.56, the angle of repose was 35 degrees, and the particle size distribution was as shown in Table 2 below.

[0037]

[Table 2]

As shown in each of the examples, AO-60 having a β crystal structure was obtained by crystallization using a solvent having a specific composition of the present invention consisting of lower alcohol / water / saturated aliphatic hydrocarbon. The obtained particles can be obtained as coarse particles, and the obtained AO-60 has a high purity, a large apparent specific gravity, a small angle of repose, and the particle size distribution before and after shaking hardly changes. It is clear that the strength is also high.

On the other hand, when a conventionally known solvent that does not use an aliphatic hydrocarbon is used, β crystals cannot be stably obtained, and the obtained crystals have a small content rate. Clearly has a drawback that the particle size distribution changes after shaking because the crystal strength is low and the crystal strength is low.

[0040]

INDUSTRIAL APPLICABILITY Tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is used in a solvent having a specific composition of lower alcohol / water / saturated aliphatic hydrocarbon. By crystallization, tetrakis [3- (3,5-ditertiarybutyl-4-hydroxyphenyl) propionyloxymethyl] methane having a β crystal structure can be stably obtained as coarse particles.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryozo Arata Yamada, Toin-cho, Inabe-gun, Mie Prefecture (No house) Asahi Denka Co., Ltd. Mie factory

Claims (1)

[Claims] 1. When crystallization of tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionyloxymethyl] methane, 70 to 95% by weight of a lower alcohol and 1 to 20% of water are used as a solvent. Tetrakis [3] having a β-crystal structure, characterized in that a mixed solvent containing 0.5% by weight of a saturated aliphatic hydrocarbon solvent and 0.5% by weight of a saturated aliphatic hydrocarbon solvent is used.
-(3,5-di-tert-butyl-4-hydroxyphenyl)
Method for producing propionyloxymethyl] methane.