JPH1077247A - Granulation of triethylene glycol bis-3-(3-tertiary butyl-4-hydroxy-5-methylphenyl) propionate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To granulate a compound useful as an antioxidant, etc., by adding a water-containing lower alcohol to a specific triethylene glycol bis-3-(substituted phenyl)propionate, mixing under refluxing, adding a seed crystal and cooling the liquid. SOLUTION: Triethylene glycol bis(3-(3-t-butyl-4-hydroxy-5-methylphenyl) propionate useful e.g. as an antioxidant for polyolefins and various other synthetic polymers is stably granulated on an industrial scale in the crystallization purification of the compound by adding 1.0-2.5 pts.wt. of a lower alcohol containing 15-22wt.% of water to 1 pt.wt. of the triethylene qlycol bis(3-(3-t- butyl-4-hydroxy-5-methylphenyl)propionate, melting the components under mixing and refluxing, cooling the molten liquid, adding a seed crystal when the mixture is cooled to 20-45 deg.C and then quenching the mixture to form granules.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to an industrially stable granule of triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate useful as an antioxidant. The present invention relates to a novel crystallization purification method to be obtained.

[0002]

BACKGROUND OF THE INVENTION Triethylene glycol bis-3- (3-tert-butyl-
4-Hydroxy-5-methylphenyl) propionate (hereinafter sometimes referred to as compound (I)) is a compound widely used as an antioxidant for various synthetic polymer materials including polyolefins.

The compound (I) becomes a powder when crystallized by an ordinary method such as recrystallization in a solvent such as alcohol, contains a large amount of dust, has a low bulk specific gravity, has poor fluidity, and is easily scattered. In addition to inconvenience in handling, there is a problem in terms of working efficiency when using it and a working environment. As a method for improving such powder properties, a method of granulating is generally known.

[0004] As a method of granulation, a method using a binder and a method using a physical method such as pressurization and melting and solidification are known. When a binder is used, components other than the target substance are mixed. As a result, the purity of the product was reduced, while the physical method sometimes resulted in irregular shapes or block solids during storage. In addition, any method requires dedicated production equipment, and a simple industrially advantageous production method has been desired.

[0005]

Means for Solving the Problems In order to solve the above problems, the present inventors have conducted intensive studies to find a simple granulation method which can be carried out on an industrial scale, and as a result, the compound (I) In a lower alcohol having a specific water content at the time of crystallization purification, or in a lower alcohol having a specific water content to which an aromatic and / or aliphatic hydrocarbon is added.
It has been found that compound (I) can be obtained as granules by adding seed crystals at 45 ° C. and then rapidly cooling, thereby completing the present invention.

That is, the present invention relates to (1) triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate for crystallization and purification.
(3-tert-butyl-4-hydroxy-5-methylphenyl) propionate is added with 15 to 22% by weight of a water-containing lower alcohol in an amount of 1.0 to 2.5 times by weight, melt-mixed under reflux, and then cooled. At 20-45 ° C. to add seed crystals,
Thereafter, the mixture is rapidly cooled to produce granular triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, wherein triethylene glycol bis-3- (3
-A method for granulating tertiary butyl-4-hydroxy-5-methylphenyl) propionate; and (2) the method according to the above-mentioned 1, wherein the method is carried out in the presence of an aromatic and / or aliphatic hydrocarbon. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The method for granulating the compound (I) of the present invention will be described below in more detail. In the method of the present invention, a lower alcohol having a specific water content is used when melt-mixing the compound (I), and when cooling after melt-mixing, a seed crystal is added, particularly at 20 to 45 ° C., followed by rapid cooling. As a result, a granular compound (I) with less generation of dust can be obtained. In the present invention, the term “granular” refers to a JI of 100 mesh (aperture 0.149 mm).
It means that the weight ratio of the compound (I) passing therethrough is 5% or less as measured by an S standard sieve. In the present invention, since granular crystals do not precipitate even when cooled without adding seed crystals,
Preferably, a seed crystal is added.

The compound (I) used in the method of the present invention is
Preferably, a reaction mixture of compound (I) obtained by a transesterification reaction of triethylene glycol and a lower alkyl ester of 3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionic acid is used. Compound (I) in the form of a powder obtained by the crystallization method described above can also be used.

The reaction mixture of compound (I) used in the method of the present invention may be used as a transesterification reaction product,
A residue (often in the form of a candy) obtained by concentrating and removing the solvent used for improving the fluidity in the catalyst removal step may be used.
The production method of the compound (I) used in the method of the present invention is not particularly limited, but preferred production methods for obtaining the compound (I) with high purity include triethylene glycol and 3- (3- Methyl tertiary butyl-4-hydroxy-5-methylphenyl) propionate is used in a solvent such as toluene, using an organotin compound such as monobutyltin oxide or dibutyltin oxide as a catalyst, or using sodium methoxide, lithium amide or the like. The transesterification reaction is performed using an alkali catalyst as a catalyst.

As the water-containing lower alcohol used in the method of the present invention, methanol, ethanol, n-propanol, isopropyl alcohol and the like are used, and these may be used alone or as a mixture of two or more. Of these, methanol and ethanol are preferred. The water content of the water-containing lower alcohol used in the method of the present invention is preferably 15 to 22% by weight, and more preferably 18 to 20% by weight. In the method of the present invention, when the water content is lower than this range, powdery crystals are precipitated, or seed crystals are dissolved, and the effect is not exhibited. On the other hand, when the water content is higher than this range, the powder is not granulated but powdered.

The aromatic hydrocarbon used in the method of the present invention includes toluene, xylene, mesitylene, benzene and the like, and toluene is preferred. Examples of the aliphatic hydrocarbon used in the method of the present invention include pentane, hexane, heptane, octane, nonane and the like, and preferably heptane. Further, in the granulation method of the present invention,
A granular compound may be obtained in which an aromatic or aliphatic hydrocarbon may be added to a water-containing lower alcohol, and the aromatic or aliphatic hydrocarbon may be used alone or as a mixture.

The amount of the aromatic and / or aliphatic hydrocarbon is 0.1 to 20% by weight based on the weight of the hydrated lower alcohol.
And preferably 0.5 to 5% by weight. If the amount of the aromatic and / or aliphatic hydrocarbon added is too large, the yield decreases, or the crystals are dissolved by the remaining aromatic and / or aliphatic hydrocarbon during drying, which is not preferable.

The amount of the water-containing lower alcohol used in the method of the present invention or the water-containing lower alcohol in the coexistence of an aromatic and / or aliphatic hydrocarbon is from 1.0 to 1.0 with respect to the theoretical amount of the compound (I). Used 2.5 times by weight.
In particular, it is preferable to use 1.5 to 2.0 times by weight. In the method of the present invention, if the amount used is small, the purity does not increase, and stirring becomes difficult, so that a uniform particle size is not obtained. On the other hand, when the amount used is large, the yield is reduced, and the powder is not granulated but powdered.

In the crystallization purification step, the temperature of the reaction mixture is controlled under reflux in a 15 to 22% by weight aqueous lower alcohol, or in a 15 to 22% by weight aqueous lower alcohol to which aromatic and / or aliphatic hydrocarbons are added. After dissolving the powdered compound (I), the solution is cooled and a seed crystal is added at 20 to 45 ° C, preferably 30 to 40 ° C, and then rapidly cooled. Since the seed crystal may be dissolved at a temperature higher than 45 ° C., it is preferable to add the seed crystal at 45 ° C. or lower. The quenching after the addition of the seed crystal is quenching when industrially performed, and is 3 to 20 ° C. per hour.
Cooling rate is preferred, more preferably 5 per hour.
The cooling rate is 〜20 ° C., and if the cooling rate is higher or lower than this range, the precipitated crystals are pulverized.

[0015]

EXAMPLES Hereinafter, the present invention will be described specifically with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to these. Reference Example 1 In a 500 ml four-necked flask equipped with a stirrer, a condenser and a thermometer, 3- (3-tert-butyl-4-hydroxy-
Methyl 5-methylphenyl) propionate 156.4
g, 46.0 g of triethylene glycol and 0.11 g of dibutyltin oxide were added, and the temperature was raised to 180 ° C., and the generated methanol was distilled off under reduced pressure to complete the reaction. After that, return to atmospheric pressure by introducing nitrogen gas,
Dissolved in 182 g of toluene. A water separator was attached, and 0.1 g of oxalic acid was added to this toluene solution.
1) 0.2 g of (trade name, manufactured by Mizusawa Chemical) is charged and 118
The temperature was raised to 0 ° C., and a dehydration reaction was performed for 2 hours. Thereafter, the toluene layer was filtered with a pressure filter, and then toluene was distilled off under reduced pressure to obtain triethylene glycol bis-3- (3
-Tert-butyl-4-hydroxy-5-methylphenyl) propionate was obtained as a pale yellow candy.

Example 1 100 g of the candy substance obtained in Reference Example 1 was dissolved in 165 g of 20% by weight aqueous methanol under reflux, cooled to 40 ° C., and 0.5 g of a seed crystal was introduced. Then, it cooled to 20 degreeC in 1 hour. The precipitate became white granules, and was filtered and dried to obtain 83.6 g of white granules.

Example 2 83.4 g of white granules were obtained in the same manner as in Example 1 except that the amount of methanol containing 20% by weight of water was changed to 235 g. Example 3 White granules were obtained in the same manner as in Example 1 except that 20% by weight of aqueous methanol was replaced by 21% by weight of aqueous ethanol.
0 g was obtained.

Example 4 100 g of the candy-like substance obtained in Reference Example 1 was dissolved in 165 g of 18% by weight aqueous methanol under reflux, cooled to 40 ° C., and 0.5 g of a seed crystal was introduced. After that, one hour
Cooled to 0 ° C. The precipitate becomes white granules, filtered,
Drying yielded 81.7 g of white granules.

Example 5 100 g of the candy substance obtained in Reference Example 1 was dissolved under reflux in a mixed solution of 158.5 g of methanol containing 20% by weight of water and 6.6 g of toluene, cooled to 40 ° C., and cooled to 0.5 g. A seed crystal was charged. Then, it cooled to 20 degreeC in 1 hour. The precipitate becomes white granules, which are filtered and dried to obtain white granules 8
2.3 g were obtained.

Example 6 The same operation as in Example 5 was carried out except that heptane was used instead of toluene, and white granules 8 were prepared.
2.5 g were obtained. Example 7 In a 1-liter four-necked flask equipped with a stirrer, a condenser, a thermometer and a dropping device, 3- (3-tert-butyl-4-) was added.
250.3 g of methyl hydroxy-5-methylphenyl) propionate, 75.1 g of triethylene glycol, 0.80 g of dibutyltin oxide and 32.5 g of toluene
g was charged and reacted at 180 ° C. to 185 ° C. for 12 hours with stirring. During the reaction, 500 g of toluene was added dropwise and distilled off together with the produced methanol. After the reaction, toluene 20
0 g was added and uniformly dissolved. A water separator was attached, and 0.80 g of oxalic acid and 2.6 parts of acid clay were added to this toluene solution.
3 g was added, the temperature was raised to 118 ° C., and a dehydration reaction was performed for 2 hours. Thereafter, the toluene layer was cooled and filtered with a pressure filter, and then toluene was distilled off under reduced pressure to obtain triethylene glycol bis-3- (3-tert-butyl-4).
-Hydroxy-5-methylphenyl) propionate was obtained as a pale yellow candy. The same operation as in Example 1 was performed on 100 g of this candy substance, and 83.5 white granules were obtained.
g was obtained.

Example 8 A pale yellow candy substance was obtained in the same manner as in Reference Example 1, except that the amount of dibutyltin oxide used was changed to 0.07 g. The same operation as in Example 1 was performed on 100 g of this candy-like substance to obtain 82.8 g of white granules. Comparative Example 1 100 g of the candy-like substance obtained in Reference Example 1 was dissolved in 165 g of 25% by weight aqueous methanol under reflux and cooled to 40 ° C., and then 0.5 g of seed crystal was put therein and cooled to 20 ° C. in 1 hour. did. The precipitate turned into a white powder, which was filtered and dried to obtain 85.4 g of a white powder.

Comparative Example 2 85.8 g of a white powder was obtained in the same manner as in Comparative Example 1 except that the amount of 25% by weight aqueous methanol was changed to 200 g. Comparative Example 3 100 g of the candy substance obtained in Reference Example 1 was dissolved in 165 g of 12% by weight aqueous methanol under reflux and cooled to 40 ° C., and then 0.5 g of seed crystal was put therein and cooled to 20 ° C. in 1 hour. did. The precipitate became a white powder, which was filtered and dried to obtain 75.7 g of a white powder.

Comparative Example 4 100 g of the candy substance obtained in Reference Example 1 was dissolved in 165 g of 20% by weight aqueous methanol under reflux, cooled to 40 ° C., and 0.5 g of a seed crystal was added. Cooled to ° C. Filtration and drying yielded 83.5 g of a white powder. The purity of the compound (I) obtained in the above Examples and Comparative Examples was measured by liquid chromatography. Also,
50 g of each obtained sample was sieved through a 100-mesh sieve, and the generation of dust was evaluated by the weight of the compound (I) that passed through the mesh. Compounds (I) passing less than 2.5 g through the sieve were evaluated as ○ because there was no dust, and those with 2.5 g or more were evaluated as × because dust was generated. Table 1 shows the results.

[0024]

[Table 1]

As is apparent from the results of the above Examples and Comparative Examples, triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate was purified by crystallization. Seeding at 20-45 ° C. in 22% by weight aqueous lower alcohol, or in 15-22% by weight aqueous lower alcohol to which aromatic and / or aliphatic hydrocarbons are added,
By quenching, granular triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5
-Methylphenyl) propionate can be produced.

On the other hand, as shown in Comparative Examples 1 and 2, when crystallization purification was carried out using an alcohol solvent having a high water content in advance, crystallization of compound (I) in the system after seeding was added. The target is precipitated as a powder due to the high speed.
In addition, when the water content is low as shown in Comparative Example 3, or even when cooled slowly as shown in Comparative Example 4, it is precipitated as powder crystals and does not reach the target granulation of the present invention. It is clear.

[0027]

EFFECT OF THE INVENTION Triethylene glycol bis-3-
When (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate is purified by crystallization, 15-
22 to 22% by weight in water-containing lower alcohol or 15 to 22% by weight to which aromatic and / or aliphatic hydrocarbons are added
Seed crystals are added at 20 to 45 ° C. in hydrous alcohol, and then quenched to obtain a granular triethylene glycol bis-3 excellent in handling by a simple method that does not require special equipment for granulation. -(3-tert-butyl-4
-Hydroxy-5-methylphenyl) propionate can be prepared.

Further, the obtained granular compound has features such as low generation of dust, high bulk specific gravity, good fluidity, and difficulty in scattering, and therefore, the handling of the compound is facilitated.
This is very useful in that workability and work environment can be improved.

Claims (2)

[Claims] (1) Triethylene glycol bis-3-
When (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate is crystallized and purified, triethylene glycol bis-3- (3-tert-butyl-4
-Hydroxy-5-methylphenyl) propionate is mixed with 15 to 22% by weight of a water-containing lower alcohol in an amount of 1.0 to 2.5 times by weight, melt-mixed under reflux, cooled, and seeded at 20 to 45 ° C. And then rapidly cooled to obtain granular triethylene glycol bis-3- (3-
Tertiary butyl-4-hydroxy-5-methylphenyl)
A method for granulating triethylene glycol bis-3- (3-tert-butyl-4-hydroxy-5-methylphenyl) propionate, which comprises producing propionate. 2. The method according to claim 1, wherein the method is carried out in the presence of an aromatic and / or aliphatic hydrocarbon.