JPH0515698B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides finely granular tetrakis[3-(3,5-di-t-butyl)-4-hydroxyphenyl)propionyl, which is represented by the following formula () and has good properties. Regarding the production method of [oxymethyl]methane, for more details, please refer to tetrakis[3-(3,5-di-t-butyl)-4-hydroxyphenyl)propionyloxymethyl having a normal crystal structure such as α crystal or β crystal. ] From methane, the wavelength of Cu-Kα
Diffraction angle 2θ=
Fine-grained tetrakis [3-(3,5-di-t
The present invention relates to a method for producing -butyl)-4-hydroxyphenyl)propionyloxymethyl]methane. (Conventional technology) (However, t-Bu represents a tertiary butyl group.) The compounds represented by () above include polypropylene, polyethylene, polyvinyl chloride, polyester, polystyrene, ABS resin, polyurethane,
It is a well-known fact that it is used as an antioxidant for polyacetal and other products. This compound () is commercially available, but the powder form of the commercially available product is a fine white powder.
(1) It has a low bulk specific gravity, (2) It is a fine powder and will scatter into the air when handled, (3) It will form into blocks during transportation and storage, (4) It has poor fluidity, and for example, it cannot be used with polypropylene in an extruder. It was unsatisfactory in terms of workability, transportability, weighability, etc., such as poor weighability during melt-mixing. On the other hand, tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane is 3-(3,5-di-t-butyl-4-hydroxyphenyl) represented by the general formula (). It is known that it can be produced by transesterifying propionic acid alkyl ester and pentaerythritol. (However, in the formula, t-Bu represents a tertiary butyl group, and R is a methyl group or an ethyl group.) For example, in the specification of Japanese Patent Publication No. 42-19083, propionic acid ester () is combined with pentaerythritol. It is disclosed that isopropanol is added to the product after the transesterification reaction to liberate a molecular adduct of compound (), and subsequent recrystallization with heptane yields the target compound () with a melting point of 121 to 122°C, and In the specification of Japanese Patent Publication No. 42-18617, the product after the transesterification reaction is chromatographed on neutral alumina while eluting with hexane solvent to remove impurities, and the softening point of the transparent amber color is further removed by removing hexane. It is disclosed that the desired product () is obtained as a glassy substance at 50-60 °C,
Furthermore, according to another description in the same specification, when the reaction product is recrystallized with a heptane solvent, the melting point is 119-122°C,
Melting point 80-90 when recrystallized with cyclohexane solvent
It is disclosed that the compound ( ) can be obtained at . When the present inventor produced the compound () according to the methods described in these known documents, the crystals of the obtained compound () were all in the form of a fine powder with poor fluidity or were colored yellow. It was something that I would do. As a result of analyzing these commercially available compounds () or the compounds () obtained by the method disclosed in the above-mentioned known literature, the present inventors found that Compounds () are both α crystal and β crystal defined below.
It had a crystal structure of either crystal or gamma crystal. In the present invention, the α-crystal compound () refers to Cu
It has the diffraction X-ray spectrum shown in FIG. 1 when measured by the powder method using X-rays of -Kα wavelength. Figure 1 shows the diffraction angle 2θ of the α-crystal compound ().
(horizontal axis) and diffraction In particular, the α crystal has a diffraction angle
Two peaks are observed in the 2θ range of 5 to 10° that are not observed in the δ crystal described later, and the diffraction angle
It is characteristic that no diffraction X-ray peak is observed at 2θ=10.90°, and the α-crystal compound () has a high melting point of about 120 to 125°C. Such α-crystal compounds () are, for example, disclosed in the aforementioned Japanese Patent Publication No. 42-
C or Tokkosho of Example 2 of the specification of the publication No. 18617
It is obtained by the method described in Example 1 of the specification of Japanese Patent No. 42-19083. This α-crystal compound ()
It has the disadvantage that it is either colored or, when purified to a high purity without coloring, it can only be obtained as a low specific gravity and fluid powder. Further, in the present invention, the β-crystalline compound () has a diffraction X-ray spectrum shown in FIG. 2 when measured by a powder method. The horizontal axis in Figure 2,
The vertical axis is exactly the same as in Figure 1. As is obvious at first glance, the β crystal, like the α crystal, has many more intense diffraction X-ray peaks than the δ crystal, which will be described later. There are 5 peaks due to diffraction X-rays that are not observed in crystals.
The existence of this and the diffraction angle 2θ existing in the δ crystal
It is characteristic that the peak at =10.90° is not observed. The melting point of the β-crystalline compound () is 109-115°C. Such β-crystal compounds are described in the above-mentioned JP-A-49-
This β-crystalline compound is obtained by the method described in Example 4 of the Specification of Publication No. 94644, but is colored yellow, and when purified repeatedly to make it colorless, it becomes a fine powder with poor fluidity. Also, γ-crystal compounds ()
is X shown in Figure 3 when measured using the powder method.
It has a line diffraction spectrum and a softening point of 100°C or less. Compounds with such γ crystals ()
is Example 2 of the specification of the above-mentioned Japanese Patent Publication No. 18617/1973
However, these γ-crystal compounds () are amorphous and have the disadvantage of being difficult to handle. Note that the X-ray diffraction measurement and spectrum will be explained in detail below. Therefore, in this technical field, compounds of α, β, or γ crystals, which have low bulk specific gravity and are available only as powders, colored substances, or amorphous substances, are being handled in place of the above-mentioned α, β, or γ crystal compounds. It was desired to obtain a colorless, fine-grained compound (2) that is easy to use and has good properties. Therefore, one of the inventors of the present invention has already developed a method for obtaining the compound () as colorless fine particles with good properties. -4-Hydroxyphenyl) propionic acid alkyl ester and pentaerythritol are transesterified into compounds represented by general formula (V). (However, in the formula, t-Bu represents a tertiary butyl group, and R represents a methyl group or an ethyl group). A new crystal structure (i.e., a δ crystal structure defined below) that shows a sharp diffraction X-ray peak at a diffraction angle of 2θ = 10.90° is obtained by recrystallizing with methanol and diffracting X-rays using X-rays with a wavelength of Cu-Kα. ) proposed a method to obtain the compound ( ). (Japanese Patent Publication No. 60-13017, Japanese Patent Publication No. 60-13018) However, this method is effective when producing the compound () by transesterification, and once the α crystal or/and β crystal is produced like a commercially available product. This is not a method to obtain a fine-grained compound () with a δ crystal structure from a compound () extracted as . [Objective of the Invention] (Problems to be Solved by the Invention) The present inventors have developed a compound () which has been extracted as an α-crystal, a β-crystal, or a γ-crystal into a δ-crystal structure, which is a fine particle with good properties. As a result of intensive research on the method of converting compound () into compound (), it was found that by melting alpha, beta or gamma crystal compound () in the presence of a specific compound and recrystallizing it with ethanol or methanol. The inventors have found that this object can be achieved and have completed the present invention. [Structure of the invention] (Means for solving the problem) That is, the present invention is represented by the formula (),
Tetrakis [3-
(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl]methane or a mixture of two or more thereof is melted in the presence of a compound represented by formula () or/and formula (). , followed by recrystallization with methanol or/and ethanol ()
Diffraction X using X-rays with the wavelength of Cu-Kα
Fine-grained tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionyloxymethyl] having a crystal structure that shows a sharp diffraction X-ray peak at a diffraction angle of 2θ = 10.90° by line measurement. ] This relates to a method for producing methane. (However, in the formula, t-Bu represents a tertiary butyl group.) (However, in the formula, t-Bu represents a tertiary butyl group, and R represents a methyl group or an ethyl group.) (However, in the formula, t-Bu represents a tertiary butyl group.) In the present invention, the δ-crystal compound () means Cu
Compounds with a crystal structure in which the diffraction X-ray intensity with respect to the diffraction angle 2θ shows the pattern shown in Table 1 by diffraction X-ray measurement using a wavelength of -Kα, and a particularly sharp diffraction X-ray peak at the diffraction angle 2θ = 10.90° ().

〔Effect of the invention〕

The compound () obtained by the present invention is a white, fine-grained compound with a δ-crystal structure that has excellent properties such as high bulk specific gravity and high fluidity.
It is significantly superior to crystalline compounds () in terms of workability, transportability, weighability, etc. In addition, in the present invention, compounds () which have been extracted as α crystals and/or β crystals like commercially available products are used.
The above white, fine-grained δ can be obtained in a relatively simple way from
This is an industrially significant invention since it is possible to obtain a compound () having a crystal structure. Next, the present invention will be explained in more detail with reference to Examples. Reference Example [Synthesis of Compound () and Compound ()] 17.65 g of Compound () was placed in a 100 ml 4-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube.
Potassium-t-butoxide 0.2g and a compound represented by the general formula (), in which R is a methyl group
Add 8.48g and stir under nitrogen gas atmosphere.
The mixture was heated at 165° C./0.2 mmHg for 12 hours, and the resulting compound represented by the general formula (), in which R is a methyl group, was distilled off to complete the reaction. After cooling the reaction product, it was neutralized by adding glacial acetic acid, dissolved by adding 100 ml of benzene, washed and desalted with warm water, and then benzene was distilled off to obtain a crude product. This crude product was mixed with silica gel (Wako Pure Chemical Industries, Ltd.)
Chromatographic separation was performed using a column packed with Wakogale C-200 (manufactured by Wakogale, Inc., product name: Wakogale C-200), with a melting point of 50.5-52.
℃, 1.1 g of compound () with purity 96.5% and melting point 66
0.6 g of compound () with a purity of 83% was obtained at ~69°C. Example 1 Into a 300 ml 4-necked flask equipped with a stirrer, reflux condenser, thermometer, and nitrogen inlet tube, α with bulk specific gravity 0.39, falling speed ⁽¹⁾ 150 seconds/200 ml, melting point 123-125°C, purity 99% or more Add 100.0 g of compound () with crystal structure and 0.2 g of compound (), maintain the temperature at 130 to 140°C while stirring under nitrogen gas atmosphere, and after completely melting, immediately lower the temperature to below 100°C, take out, and cool. Solidify to obtain a γ-crystal compound () containing compound (), add 300 ml of 95% ethanol to this compound () and heat it to form a homogeneous container, cool it to room temperature, recrystallize it, and increase the bulk specific gravity by filtration. 0.57, falling speed 29 seconds/200
100 g of fine granular white crystals were obtained. This compound () was confirmed to be a δ crystal by X-ray diffraction using a wavelength of Cu-Kα. Melting point 112-114℃ measured using a melting point measuring device with a microscope
Further, the crystal purity analyzed by liquid chromatography was 99% or more. (1) 200 ml of sample is charged into a hopper consisting of a hollow cylindrical part and a truncated conical part, and the number of seconds required for the entire volume to flow.
Using 0.15 g of compound () and 0.45 g of compound (), after completely melting, it was cooled to 80 °C, and before the contents solidified, 95% ethanol was added and cooled to room temperature to precipitate crystals. The same operation as in Example 1 was performed. 100 g of fine-grained white crystals were obtained, and X-ray diffraction (Cu-Kα) confirmed that the compound was a δ-crystal compound (). Example 3 In Example 2, a commercially available fine powder α with a bulk specific gravity of 0.04 to 0.39, a falling speed of 455 seconds/200 ml, and a melting point of 110 to 124°C was used.
Compound () with a crystal/β crystal composition ratio (molar ratio) of 80/20 (manufactured by Ciba Geigy, trade name: Irganox
1010) The same operation as in Example 2 was performed except that 100.0 g was used. The obtained crystals were fine-grained δ-crystal structure compound (). Comparative Example 1 In Example 1, α-crystal compound () and compound ()
Without melting the mixture, 95% ethanol was added from the beginning to dissolve under reflux, and the crystals precipitated by cooling were confirmed to be alpha crystals by X-ray diffraction, and the melting point was 122-125.
It was warm at ℃.

[Brief explanation of the drawing]

Figures 1, 2, and 3 are α crystal, β crystal, and γ crystal, respectively.
This is an X-ray diffraction pattern of crystalline compound (). Moreover, FIG. 4 is an X-ray diffraction pattern of the δ-crystal compound ().

Claims (1)

[Scope of Claims] 1 Tetrakis [3-(3,5-di-t
-butyl-4-hydroxyphenyl)propionioxymethyl]methane or a mixture of two or more thereof is melted in the presence of a compound represented by formula () or/and formula (), and then methanol or/ The diffraction angle 2θ was determined by diffraction X-ray measurement using X-rays with the wavelength of Cu-Kα.
Tetrakis [3-(3,5-di-
A method for producing t-butyl-4-hydroxyphenyl)propionioxymethyl]methane. (However, in the formula, t-Bu represents a tertiary butyl group. The same applies hereinafter.) (However, in the formula, t-Bu represents a tertiary butyl group, and R represents a methyl group or an ethyl group.) (However, in the formula, t-Bu represents a tertiary butyl group.)