Indophenol

Indophenol is an organic compound with the formula OC₆H₄NC₆H₄OH. It is deep blue dye that is the product of the Berthelot's reaction, a common test for ammonia.[2] The indophenol group, with various substituents in place of OH and various ring substitutions, is found in many dyes used in hair coloring and textiles.[3]

Indophenol

Names
IUPAC name 4-(4-hydroxyphenyl)iminocyclohexa-2,5-dien-1-one
Other names Benzenoneindophenol, phenolindophenol[1]
Identifiers
CAS Number	500-85-6
3D model (JSmol)	Interactive image
ChemSpider	9951
ECHA InfoCard	100.007.194
PubChem CID	10379
CompTox Dashboard (EPA)	DTXSID2075425
InChI InChI=1S/C12H9NO2/c14-11-5-1-9(2-6-11)13-10-3-7-12(15)8-4-10/h1-8,14H Key: RSAZYXZUJROYKR-UHFFFAOYSA-N InChI=1/C12H9NO2/c14-11-5-1-9(2-6-11)13-10-3-7-12(15)8-4-10/h1-8,14H Key: RSAZYXZUJROYKR-UHFFFAOYAS
SMILES O=C/2/C=C\C(=N\c1ccc(O)cc1)\C=C\2
Properties
Chemical formula	C12H9NO2
Molar mass	199.209 g·mol^−1
Appearance	Reddish-blue powder[1]
Melting point	above 300 °C [1]
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
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Infobox references

Indophenol is used in hair dyes, lubricants, redox materials, liquid crystal displays, fuel cells and chemical-mechanical polishing. It is an environmental pollutant and is toxic to fish.[1][4]

Berthelot test

In the Berthelot test (1859), a sample suspected of having containing ammonia is treated with sodium hypochlorite and phenol. The formation of indophenol is used to determine ammonia and paracetamol by spectrophotometry.[5] Other phenols can be used. Dichlorophenol-indophenol (DCPIP), a form of indophenol, is often used to determine the presence of vitamin C (ascorbic acid).[6]

Related compounds

Indophenol blue is a different compound with systematic name N-(p-dimethylaminophenyl)-1,4-naphthoquinoneimine.[7]

Indophenol blue

References

1. Sabnis, R. W. (2007). Handbook of Acid-Base Indicators. CRC Press. p. 196. ISBN 978-0-8493-8219-2.
2. Patton, Charles J.; Crouch, S. R. (1977). "Spectrophotometric and kinetics investigation of the Berthelot reaction for the determination of ammonia". Analytical Chemistry. 49 (3): 464–469. doi:10.1021/ac50011a034.
3. Horst Berneth (2002). "Azine Dyes". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a03_213.pub2. ISBN 978-3527306732.
4. "Indophenol I5763". 500-85-6. Retrieved 2020-06-11.
5. Tsuboi, T.; Hirano, Y.; Shibata, Y.; Motomizu, S. (2002). "Sensitivity improvement of ammonia determination based on flow-injection indophenol spectrophotometry with manganese(II) ion as a catalyst and analysis of exhaust gas of thermal power plant". Analytical Sciences : The International Journal of the Japan Society for Analytical Chemistry. 18 (10): 1141–4. PMID 12400662.
6. Hughes, David Emlyn (1983). "Titrimetric Determination of Ascorbic Acid with 2,6-Dichlorophenol Indophenol in Commercial Liquid Diets". Journal of Pharmaceutical Sciences. 72 (2): 126–129. doi:10.1002/jps.2600720208.
7. Graham, S. O. (1963). "Indophenol Blue as a Chromogenic Agent for Identification of Halogenated Aromatic Hydrocarbons". Science. 139 (3557): 835–836. Bibcode:1963Sci...139..835G. doi:10.1126/science.139.3557.835.