Phenolic antioxidants in crystalline form
AssigneeCiba Specialty Chemicals Corporation
InventorsDaniel Rehm, Johannes Schäfter, Paul Adriaan Van Der Schaaf, Christian Guckel
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Abstract
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] (μ-form) and N,N′-hexane-1,6diyl-bis[3-(3,5-di-tert-butyl-4-hydroxypheylpropamide)] (β-form) and aqueous dispersion comprising the new crystal modifications.
Claims17
A process for preparing solid particles comprising in essentially crystalline form a compound of the formula:
- 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 C8–C22alkoxy;
- or 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,
- characterised in that a homogeneous aqueous dispersion is prepared, which comprises the compound (I) or a mixture thereof, wherein R1, R2, R1′, R2′, Y, x, y and z are as defined above, crystals are formed by the addition of a fatty acid partial ester of polyoxyethylene sorbitan and seed crystals and the crystals obtained are separated from the dispersion.
A crystal form of pentaerythritol tetrakis[3-(3,5-di-tert-butyl-4-hydroxyphenyl)-propionate] characterised in the X-ray powder diffraction pattern by the interplanar spacings [d-values] and relative line intensities of the following principal lines:
- d-spacing [Å]
- Relative intensity
- 22.7
- strong
- 19.7
- strong
- 14.9
- medium
- 13.1
- medium
- 11.3
- medium
- 9.0
- weak
- 8.6
- medium
- 7.6
- weak
- 7.1
- very strong
- 6.6
- weak
- 5.94
- weak
- 5.63
- medium
- 5.45
- weak
- 5.26
- medium
- 5.06
- medium
- 4.82
- medium
- 4.74
- strong
- 4.58
- medium
- 4.43
- very strong
- 4.30
- weak
- 4.09
- weak
- 3.93
- weak
- 3.75
- weak.
A crystal form of N,N′-hexane-1,6-diyl-bis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)] characterised in the X-ray powder diffraction pattern by the interplanar spacings [d-values] and relative line intensities of the principal lines:
- d-spacing [Å]
- Relative intensity
- 7.3
- medium
- 5.13
- strong
- 4.88
- medium
- 3.92
- weak.
A crystal modification (β-form) of N,N′-hexane-1,6-diyl-bis[3-(3,5-di-tert-butyl-4-hydroxyphenylpropionamide)] characterised in the X-ray powder diffraction pattern by the following interplanar spacings [d-values] and relative line intensities including the principal lines and weaker lines:
- d-spacing [Å]
- Relative intensity
- 16.0
- very weak
- 13.6
- very weak
- 12.7
- very weak
- 11.1
- weak
- 10.5
- medium
- 10.3
- medium
- 9.1
- very weak
- 8.5
- weak
- 8.0
- medium
- 7.9
- medium
- 7.5
- medium
- 7.3
- medium
- 7.1
- medium
- 6.8
- weak
- 6.4
- weak
- 6.2
- medium
- 6.1
- medium
- 5.94
- weak
- 5.83
- very weak
- 5.58
- medium
- 5.24
- medium
- 5.13
- strong
- 5.06
- strong
- 4.98
- medium
- 4.88
- medium
- 4.71
- medium
- 4.59
- strong
- 4.54
- strong
- 4.38
- strong
- 4.24
- medium
- 4.13
- medium
- 3.92
- weak
- 3.85
- weak
- 3.71
- very weak
- 3.53
- weak
- 3.38
- very weak
- 3.29
- very weak
- 3.05
- very weak.
Dependencies are inferred from the claim text.