JP2997376B2 - Independent particulate tris (3,5-ditert-butyl-4-hydroxybenzyl) isocyanurate and process for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to tris (3,5-) which is widely used as an antioxidant for polyolefins.
The present invention relates to a substantially cubic or rectangular parallelepiped of di-tert-butyl-4-hydroxybenzyl) isocyanurate and an independent particulate crystal composed of an aggregate thereof.

[0002]

2. Description of the Related Art Tris (3,5-di-tert-butyl-4-)
Hydroxybenzyl) isocyanurate (hereinafter referred to as Compound I
) Is disclosed in JP-B-53-28438. That is, compound I has 2,
It is disclosed that the compound is obtained by heating 6-ditertiary butylphenol, isocyanuric acid, paraformaldehyde as a main raw material in an organic solvent such as dimethylformamide or acetonitrile in the presence of a basic catalyst such as hexamethylenetetramine. ing.

[0003] The compound I thus obtained and the product of the compound I currently on the market are, as shown in the micrographs of FIGS. 3 and 4, an aggregate of microcrystals, ie, a columnar shape or a finely divided fine particle thereof. Therefore, it has poor fluidity and is inferior in so-called powder characteristics such as easy scattering during handling, and has important problems in workability, meterability, and environmental hygiene, and its improvement is desired.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a compound I in the form of independent particles consisting of a substantially cubic or rectangular parallelepiped and an aggregate thereof, having high purity and excellent powder properties. .

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have conducted intensive studies and as a result, have found that toluene and acetonitrile can be reacted with 2,6-di-tert-butylphenol, isocyanuric acid and paraformaldehyde. Alternatively, by reacting and crystallizing in a solvent to which benzene is added in combination, or stirring a compound I having a poor powder property in a fine powder such as a commercially available product at room temperature for several hours in a solvent in which toluene or benzene is added to acetonitrile. It has been found that a compound I in the form of independent particles consisting of a substantially cubic or rectangular parallelepiped and an aggregate thereof having a high purity and excellent powder properties can be obtained by an extremely simple operation. Reached.

That is, the present invention relates to (1) tris (3,5-ditert-butyl-4-hydroxybenzyl) isocyanurate, which is an independent particulate crystal substantially consisting of a cube or a rectangular parallelepiped and an aggregate thereof; (2) Compound I in which the ratio of crystal particles having a crystal particle diameter of less than 10 μm is 1% by weight or less, and (3) 50 to 500 μm in which the ratio of crystal particles having a crystal particle diameter of more than 500 μm is 1% by weight or less.
A compound I in which the ratio of the crystal particles is 80% by weight or more and the ratio of the crystal particles smaller than 10 μm is 1% by weight or less,
(4) Compound I obtained by crushing the crystals, (5) 2,6-di-tert-butylphenol in acetonitrile solvent,
A method for obtaining tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate by reacting isocyanuric acid and paraformaldehyde, wherein toluene or benzene is used in combination.
(6) the method according to the above (5), wherein the addition of toluene or benzene is performed before the start of the reaction; (7) the method according to the above (5), wherein the addition of toluene or benzene is performed after the completion of the reaction;
(8) The amount of toluene or benzene to be added depends on the amount of isocyanuric acid or tris (3,5-di
6. The method according to the above item 5, wherein the molar amount is 0.5 to 5 times the molar amount of (tert-butyl-4-hydroxybenzyl) isocyanurate.

The present invention is characterized in that crystallization is carried out by adding and using toluene or benzene using acetonitrile as a solvent, and independent particulate crystals are not formed by adding xylene. In addition, the coexistence of water can increase the yield of independent particulate crystals.

In the present invention, toluene or benzene can be added during the reaction of 2,6-di-tert-butylphenol, isocyanuric acid and paraformaldehyde, or 2,6-di-tert-butylphenol, isocyanuric acid and paraformaldehyde can be added. After obtaining a crude reaction product of an acid and paraformaldehyde, or after suspending and stirring fine powder crystals of a commercial product or the like in an acetonitrile solvent, it can also be added.

In the present invention, when the independent particulate crystals are crystallized by the above-mentioned method, toluene or benzene is used in a molar amount of 0.5 to 5 times, preferably 1 to 3 times the amount of Compound I.
Add twice the molar amount. If the molar amount is less than 0.5 times, homogeneous independent particulate crystals cannot be obtained, and if the molar amount is more than 5 times, the independent particulate crystals are formed once, but the independent particulate crystals are destroyed and cannot be stirred. This causes a serious problem in operation. The temperature of crystallization or suspension stirring is -5 to 40
° C, preferably 10 to 20 ° C, and the stirring time is 1 to 1
0 hours, preferably 2-3 hours.

The crude reaction product is obtained, for example, under pressure or normal pressure, and the reaction under normal pressure is industrially preferable. The reaction temperature is about 50 to about 100 ° C, preferably the reflux temperature of the solvent used. The reaction time is usually about 1 to 15 hours. In this reaction, triethylamine, di-n-butylamine, piperidine and the like can be used as a basic catalyst. In addition, two or more of the above amines can be used in combination for the purpose of enhancing the catalytic activity by a synergistic effect.

[0011]

The compound I obtained by the present invention is, as shown in the photomicrographs of FIGS. 1 and 2, crystal particles substantially consisting of a cube or a rectangular parallelepiped and an aggregate thereof. It can be seen that the particles have almost no particle shape and are clearly distinguished from those currently on the market as shown in the micrograph of FIG.

Furthermore, compound I obtained according to the present invention
Unlike the conventionally known microcrystalline aggregates, they have the distinctive characteristics of having essentially uniform particle size distribution, narrow width, and excellent powder characteristics because they are essentially independent particles. This is very useful in that the working efficiency and working environment can be improved in such cases. Particularly, the crystallized product from the crude reaction product has a crystal particle diameter of 50 to 200 μm.
Is 80% by weight or more, indicating a more uniform distribution.

As described above, the compound I of the present invention is very useful in that it has excellent powder properties that are not presently available in the compound I and can be easily produced.

[0014]

EXAMPLES The present invention will now be described specifically with reference to examples, but the present invention is not limited to these examples.

Example 1 126.2 g of 2,6-di-tert-butylphenol, 25.8 g of isocyanuric acid, and paraformaldehyde (purity: 9
(2%) 19.6 g, acetonitrile 258 g, toluene 18.4 g and water 31 g were put in a flask, then 10.1 g of triethylamine and 0.2 g of di-n-butylamine were added, and the mixture was heated and refluxed for 7 hours while stirring. . Next, after neutralizing with 6.1 g of acetic acid, the reaction mixture was cooled with stirring, and the mixture was stirred at 15 to 20 ° C. for 2 hours. The precipitate was collected by filtration, washed with 180 g of acetonitrile, dried, and dried. 2 g of compound I having good fluidity was obtained as independent particulate crystals (yield 92.6%). Melting point 22
0.3 ° C. Purity by high performance liquid chromatography 9
9.7%.

Example 2 126.3 g of 2,6-di-tert-butylphenol, 25.8 g of isocyanuric acid, and paraformaldehyde (purity: 9
2%) 19.96 g, 260 g of acetonitrile and 55 g of water were placed in a flask, and then triethylamine 1
0.1 g and 0.2 g of di-n-butylamine were added, and the mixture was heated and refluxed for 5 hours while stirring. Next, after neutralizing with 6 g of acetic acid, 36.8 g of toluene was added at 70 ° C. The reaction mixture is cooled with stirring and kept at 15-20 ° C for 2 hours.
After stirring for an hour, the precipitate was collected by filtration, and acetonitrile 150
g, and dried to obtain 148.0 g of a compound I having good fluidity as independent particulate crystals (yield 94.4).
%). Melting point 220.3 ° C. Purity 99.7% by high performance liquid chromatography.

EXAMPLE 3 156.8 g of a commercially available compound I (1) and acetonitrile (2)
82 g, 46.0 g of toluene and 25 g of water were put in a flask, and the mixture was stirred in a slurry state at 20 to 25 ° C. for 2 hours. Then, the crystals were collected by filtration and dried to obtain 153.0 g of a compound I having good fluidity in the form of independent particles. Obtained as crystals (yield 97.6)
%). Melting point 220.5 ° C. Purity 99.7% by high performance liquid chromatography.

Example 4 The procedure of Example 3 was repeated except that 18.4 g of toluene and no water were used.
g of free-flowing Compound I was obtained as independent particulate crystals (yield 96.2%). Melting point 220.6 ° C. Purity 99.8% by high performance liquid chromatography.

Comparative Example 1 The same operation was performed as in Example 2, except that toluene was not used. That is, 126.3 g of 2,6-di-tert-butylphenol, 25.8 g of isocyanuric acid, 19.6 g of paraformaldehyde (92% purity), 260 g of acetonitrile and 55 g of water were put in a flask, and then 10.1 g of triethylamine and 0.2 g of n-butylamine was added, and the mixture was heated and refluxed for 5.5 hours while stirring. Then, after neutralizing with 6.1 g of acetic acid, the reaction mixture was cooled to room temperature while stirring, and the precipitate was collected by filtration, washed with 180 g of acetonitrile, dried and dried.
49.7 g of white crystals were obtained (yield 95.5%). Melting point 219.3 ° C. Purity 98.9% by high performance liquid chromatography.

Comparative Example 2 156.8 g of a commercially available compound 1 of compound I and acetonitrile 2
82 g was put in a flask, stirred in a slurry state at 20 to 25 ° C. for 2 hours, and the crystals were collected by filtration to obtain 147.3 g of Compound I as the same white powder as before the treatment. (Yield 94.6
%) Melting point 220.2 <0> C. Purity 99.6% by high performance liquid chromatography. The properties of the crystals obtained in Examples 1 to 4 and Comparative Examples 1 and 2 are shown in Table 1 in comparison with the properties of commercially available products.

[0021]

[Table 1]

In the table, 1) to 6) are as follows. 1) Value measured according to JIS K6721. 2) Value measured with a powder tester manufactured by Hosokawa Micron Corporation. 3) The smaller the numerical value of the falling speed from the stainless steel hopper shown in FIG. 5, the better the fluidity. Since Comparative Examples 1 and 2, and Commercial Products 1 and 2 did not fall naturally, hammering was always required. 4) Shimadzu Corporation; value measured with a particle size distribution analyzer, laser diffraction method, SALD-1100. 5) Ciba-Geigy; trade name: Irganox 3114. 6) Asahi Denka Co .; trade name: AO-20.

[0023]

[Brief description of the drawings]

FIG. 1 is a micrograph of the crystal obtained in Example 2, FIG. 2 is a micrograph of the crystal obtained in Example 3, FIG. 3 is a micrograph of the crystal obtained in Comparative Example 1, and FIG. (Ciba-Geigy
It is a micrograph of a company, trade name: Irganox 3114). FIG. 5 is a diagram showing a hopper used for measuring the falling time.

──────────────────────────────────────────────────続 き Continuation of front page (56) References JP-A-5-155868 (JP, A) JP-B-53-28438 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 251/34 CA (STN) REGISTRY (STN)

Claims (8)

(57) [Claims] 1. Tris (3,5) which is an independent particulate crystal substantially consisting of a cube or a rectangular parallelepiped and an aggregate thereof.
Di-tert-butyl-4-hydroxybenzyl) isocyanurate. 2. The compound according to claim 1, wherein the proportion of crystal particles having a crystal particle diameter of less than 10 μm is 1% by weight or less. 3. The proportion of crystal grains having a crystal grain size larger than 500 μm is 1% by weight or less, the proportion of crystal grains having a size of 50 to 500 μm is 80% by weight or more, and the proportion of crystal grains smaller than 10 μm is 1% by weight or less. The compound according to claim 1, which is 4. The compound according to claim 1, wherein said crystal is crushed. 5. A method for obtaining tris (3,5-di-tert-butyl-4-hydroxybenzyl) isocyanurate by reacting 2,6-di-tert-butylphenol, isocyanuric acid and paraformaldehyde in an acetonitrile solvent. The method according to claim 1, wherein toluene or benzene is used in combination. 6. The method according to claim 5, wherein the addition of toluene or benzene is performed before the start of the reaction. 7. The method according to claim 5, wherein the addition of toluene or benzene is carried out after the completion of the reaction. 8. The amount of toluene or benzene to be added depends on the amount of isocyanuric acid or tris (3,5-
The method according to claim 5, wherein the molar amount is 0.5 to 5 times the molar amount of di (tert-butyl-4-hydroxybenzyl) isocyanurate.