| 摘要 |
PURPOSE:To obtain the titled compound having fine granular gamma-crystal structure and excellent property, by melting the titled compound having alpha-crystal, beta- crystal and/or gamma-crystal structure in the presence of a specific compound and recrystallizing with methanol and/or ethanol. CONSTITUTION:A compound of formula I (t-Bu is tertiary butyl) having alpha- crystal, beta-crystal or gamma-crystal structure is melted in the presence of a compound of formula II (R is methyl or ethyl) and/or formula III. The molten compound is recrystallized with methanol and/or ethanol. The compound of formula I (useful as an antioxidant for polypropylene, etc.) can be produced from the above commercially available raw materials with simple method by the above process. The recrystallized product is a white fine granular substance having excellent properties such as high bulk density, high fluidity, etc., and excellent workability, transportability, metering performance, etc., compared with conventional compound of formula I having alpha-crystal or beta-crystal structure. It has gamma-crystal structure (a crystal structure exhibiting sharp X-ray diffraction peak at a diffraction angle 2theta of 10.90 deg. measured by X-ray diffraction measurement using Cu-Kalpha X-ray).
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