Ciba Specialty Chemicals Corporation

Basf Se Corporation

Johannes Schäfter

Paul Van Der Schaaf

Daniel Rehm

Christian Guckel

The invention relates to a process for preparing solid particles comprising a phenolic antioxidant in essentially crystalline form and to the process step of further processing the phenolic antioxidants. Solid particles are prepared from a melt of the phenolic antioxidants are added to a dispersion comprising the solid particles of the compound (I) in a mixture of an organic water-miscible solvent and water and the crystals obtained from the dispersion are separated.

Process for preparing solid particles of phenolic antioxidants

The invention relates to a process for preparing solid particles of a phenolic antioxidant from the IRGANOX series in the form of crystals, particularly IRGANOX 1010 and 1098, the crystal particles obtainable by the process, the further processing of the crystal particles, an aqueous dispersion comprising the phenolic antioxidant, novel crystal modifications of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate] (&#x3bc;-form) and N,N'-hexane-1,6diyl-bis[3-(3,5-di-tert-butyl-4-hydroxypheylpropamide)] (&#x3b2;-form) and aqueous dispersion comprising the new crystal modifications.

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Lörrach, Germany

Johannes Schäfter