JPH07116104B2 - Method for producing tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane having good powder properties - Google Patents

Description

The present invention relates to tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl), which is widely used as an antioxidant for polyolefins and the like. The present invention relates to an improved method for producing propionyloxymethyl] methane (hereinafter referred to as compound (A)).

[Conventional technology]

Since the product of the compound (A) currently on the market is a fine powder, it has poor fluidity and easily scatters during handling,
It has important problems in workability and environmental hygiene, and its improvement is desired. As a method for improving these, Japanese Patent Publication No. 60-1
3017, 60-13018, and JP-A-62-258343 are known.

[Problems to be Solved by the Invention]

The conventional method is not necessarily an economical production method, for example, the number of steps is increased and a large amount of impurities are present in order to obtain the compound (A) having good powder characteristics. That is,
In the methods of JP-B-60-13017 and JP-B-60-13018, it is necessary to add a specific dicarboxylic acid ester represented by the formula (III) during the transesterification reaction, and the compound (A) and isopropanol. Since it is necessary to isolate a molecular adduct with, the number of steps increases and it cannot be said to be an economical method.
Further, in the method of JP-A-62-258343, it is necessary to add a large amount of the compound (1) as a raw material and the tris-substituted product as an unfinished reaction intermediate before purification by recrystallization (see the same specification). If the content of the target compound (A) becomes too high at the end of the reaction as described in, the compound (1) or the tris-substituted product must be mixed), and the purity of the obtained product Is likely to be low, and at the same time the recrystallization yield is poor, which is not an economical method.

An object of the present invention is to provide a method for economically producing a compound (A) having good powder properties by a simple operation.

[Means for Solving the Problems]

In view of the above, the inventors of the present invention have made intensive studies by paying attention to the recrystallization solvent, and surprisingly found that the compound (A) is recrystallized using an aliphatic saturated hydrocarbon having 8 to 10 carbon atoms. The inventors have found that the intended purpose is achieved and have completed the present invention. The present invention is directed to tetrakis [3- (3,5-di-t-butyl-)-obtained by transesterification reaction of 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid ester and pentaerythritol. Tetrakis having good powder characteristics, characterized in that 4-hydroxyphenyl) propionyloxymethyl] methane is used as a recrystallization solvent, and an aliphatic saturated hydrocarbon having 8 to 10 carbon atoms is recrystallized alone or in a mixed solvent thereof. [3- (3,5-
It relates to a method for producing di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane.

Specific examples of the aliphatic hydrocarbon having 8 to 10 carbon atoms used in the present invention include Isopar (trade name of Exxon Chemical),
It can be used alone or as a mixture with Shell Sol (trade name of Shell Chemical), IP Solvent (trade name of Idemitsu Petrochemical). A methyl ester as the compound (I),
Ethyl ester is used. The transesterification reaction is carried out under well known conditions.

[Action]

The method of the present invention is a very simple method in which the compound (I) is transesterified with pentaerythritol and the resulting reaction product is recrystallized using a solvent used in the present invention in a weight ratio of 0.25 to 2.0. Can be done by. In the present invention, it is not necessary to add the third substance or limit the composition of the reaction product during the reaction, and the composition obtained by the usual transesterification reaction (the content of the compound (A) is 80 to 98%) is recrystallized as it is. Moreover, it is not necessary to perform a complicated operation such as forming a molecular adduct with isopropanol and recrystallizing it after isolation.

The compound (A) obtained by the present invention has characteristics such as excellent fluidity as a powder property, a uniform particle size distribution and a narrow width, and a large bulk specific gravity. When the content of the compound (A) in the reaction product is up to 90%, the product obtained by recrystallization has a crystal structure of mainly β crystal, and when it is 91% or more, a product mainly having the crystal structure of α crystal. can get. Surprisingly, α crystals were conventionally obtained only as a fine powder, and therefore the filterability was very poor, and purification by the recrystallization method was substantially impossible, but
According to this method, the compound (A) having the same quality as that of β crystal can be obtained.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

Example In a 500 ml four-necked flask equipped with a stirrer, a reflux condenser, and a thermometer, 245.6 g of methyl 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 27.2 g of pentaerythritol, and lithium amide. 0.2 g and tetralin 8 g were added, and the mixture was stirred at 130 to 140 ° C./2 to 3 Torr for 4 hours, and the produced methanol was distilled off. After that, 150 ~ 160 ℃ / 2 ~
The mixture was kept under reduced pressure of 3 Torr for 10 hours to distill off a small amount of methanol and tetralin to complete the reaction. The reaction was cooled to 120 ° C., returned to atmospheric pressure with nitrogen and then neutralized with glacial acetic acid. When the obtained reaction product was analyzed by HPLC, it contained 82% of the target compound (A). To this reaction product, 250 g of Isopar E (an aliphatic hydrocarbon having a carbon number of 8 to 10 under the trade name of Exxon Chemical Co., Ltd.) was added and dissolved by heating at 100 ° C. After cooling to 50 ° C. in 30 minutes and adding a small amount of β crystal, the mixture was crystallized by stirring at 35 to 50 ° C. for 4 hours and then at 35 to 25 ° C. for 4 hours. The crystals were separated by filtration, washed with 100 ml of cold Isopar E, and then dried to obtain 188.5 g of compound (A). This is from pentaerythritol
The yield was 80% and the crystallization yield (HPLC quantitative determination) was 95% from the compound (A) produced in the reaction.

The appearance, melting point, crystal structure, bulk specific gravity, angle of repose, orifice diameter and particle size distribution of the compound (A) thus obtained were measured and summarized in Table 1. Further, the compound (A) obtained in the same manner was recrystallized using various solvents, the properties of the crystal were measured, and summarized in Table 1 in comparison with the commercially available product.

[Effects of the Invention] As is clear from the above description, particularly Table 1, the tetrakis [3-
(3,5-Di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane is produced simply and economically.

Claims (1)

[Claims] 1. Tetrakis [3- (3,5-di-t-butyl) obtained by transesterification from 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionic acid ester and pentaerythritol. Using 4--4-hydroxyphenyl) propionyloxymethyl] methane as a recrystallization solvent, an aliphatic saturated hydrocarbon having 8 to 10 carbon atoms is recrystallized alone or in a mixed solvent thereof to obtain a good powder property. A process for producing tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyloxymethyl] methane.