@article {Tripathy:2013:2330-0760:306,
title = "Lewis Acid Mediated One Pot Solvent Free Synthesis of Phenolics Based Chimeric Azo Dyes Used as Suitable Acid-Base Indicator",
journal = "Advanced Science Focus",
parent_itemid = "infobike://asp/asfo",
publishercode ="asp",
year = "2013",
volume = "1",
number = "4",
publication date ="2013-12-01T00:00:00",
pages = "306-313",
itemtype = "ARTICLE",
issn = "2330-0760",
eissn = "2330-0779",
url = "https://www.ingentaconnect.com/content/asp/asfo/2013/00000001/00000004/art00006",
doi = "doi:10.1166/asfo.2013.1051",
keyword = "LEWIS ACID, VISIBLE COLOR, PH INDICATOR, GRINDING TECHNIQUE, PHENOLICS AZO DYE",
author = "Tripathy, Tridib and Kolya, Haradhan and Chandra, Koushik",
abstract = "Colorimetric pH responsive indicators are mainly synthetic dyes capable of changing their color upon interaction with chemical species. Their wide applications range from industry to drug design. In search for the development of a novel pH sensitive azo indicator in the pH range of
10 to 14, a novel one pot Lewis acid mediated solventfree grinding technique has been developed to synthesize various phenolics-based chimeric azo dyes. The synthesis involves in situ generation of diazonium ions in the solid phase under homogeneous mixing condition. The indicator efficiency
and the mechanism of color change of the dyes are evaluated based on their electron donor-acceptor capability. Among them, only dyes #32 and #39 have been found to act as suitable acid-base indicator in the high pH range (pH >10). Extensive UV and NMR titration studies were carried out.
Dye #32, in particular, behaves almost similar as phenolphthalein, thymolphthalein and alizarin yellow R in terms of their acid-base indicator property.",
}