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US 7,498,457 B2Granted
Process for preparing solid particles of phenolic antioxidants
AssigneeCiba Specialty Chemicals Corporation
InventorJohannes Schäfter
Life of this patent
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Abstract
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.
Claims9
A process for preparing solid particles comprising an essentially crystalline form of a compound of the formula (I):
- Wherein
- One of R1 and R2 independently of one another represents hydrogen or C1-C4alkyl and the other one represents C3-C4alkyl;
- x represents zero (direct bond) or a numeral from one to three;
- and
- Y represents groups of the partial formulae:
- Wherein
- One of R1′ and R2′ independently of one another represents hydrogen or C1-C4alkyl and the other one represents C3-C4alkyl;
- x represents zero (direct bond) or a numeral from one to three;
- y represents a numeral from two to ten;
- and
- z represents a numeral from two to six;
- characterized in that solid particles are prepared from a melt of a compound (I) by disintegration followed by full or partial solidification, the solid particles are added to a mixture of an organic water-miscible solvent and water to form a dispersion, and the crystals obtained from the dispersion are separated.
9 more elements
Dependencies are inferred from the claim text.