To use all functions of this page, please activate cookies in your browser.
With an accout for my.chemeurope.com you can always see everything at a glance – and you can configure your own website and individual newsletter.
- My watch list
- My saved searches
- My saved topics
- My newsletter
Pigment Red 170
Pigment red 170 is an organic pigment extensively used in automotive coatings. It is produced industrially by converting p-aminobenzamide into the corresponding diazonium compound followed by diazotation with 3-hydroxy-2-naphththoic acid (2-ethoxy)anilide. In the solid state the hydrazo tautomer forms and several crystal structures exist.
In the initial α polymorph the molecules are arranged in a herringbone pattern with extensive hydrogen bonding. The φ polymorph is more dense and more stable and produced industrially by thermal treatment in water at 130°C under pressure. In this phase the molecules are planar and arranged in layers. Extensive hydrogen bonding exists within the layer but between layers the only interactions are Van der Waals forces. Dense crystal structures are preferred for pigments used in coatings because in the event of Photochemical decomposition the fragments are locked in place and are able to recombine. Research shows that by replacing the ethoxy group in this compound by a methoxy group the crystal structure is less stable and in the final application and the color fades more easily. By careful selection of substituents it is possible to optimize crystal structure and improve optical properties .
Additional recommended knowledge
|This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Pigment_Red_170". A list of authors is available in Wikipedia.|