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Chlorophenol red

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Chlorophenol red
Skeletal formula of chlorophenol red in cyclic form
Ball-and-stick model of the chlorophenol red molecule in cyclic form
Names
Preferred IUPAC name 3,3-Bis(3-chloro-4-hydroxyphenyl)-2,1λ-benzoxathiole-1,1(3H)-dione
Other names 3′,3′-Dichlorophenolsulfonaphthalein
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.022.382 Edit this at Wikidata
EC Number
  • 224-619-2
PubChem CID
UNII
CompTox Dashboard (EPA)
InChI
  • InChI=1S/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23HKey: WWAABJGNHFGXSJ-UHFFFAOYSA-N
  • InChI=1/C19H12Cl2O5S/c20-14-9-11(5-7-16(14)22)19(12-6-8-17(23)15(21)10-12)13-3-1-2-4-18(13)27(24,25)26-19/h1-10,22-23HKey: WWAABJGNHFGXSJ-UHFFFAOYAK
SMILES
  • C1=CC=C2C(=C1)C(OS2(=O)=O)(C3=CC(=C(C=C3)O)Cl)C4=CC(=C(C=C4)O)Cl
Properties
Chemical formula C19H12Cl2O5S
Molar mass 423.26 g·mol
Melting point 261 °C (502 °F; 534 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C , 100 kPa). ☒N verify (what is  ?) Infobox references
Chemical compound
Chlorophenol red (pH indicator)
below pH 5.4 above pH 6.8
5.4 ⇌ 6.8

Chlorophenol red is an indicator dye that changes color from yellow to violet in the pH range 5.4 to 6.8. The pH of a substance is determined by taking the negative logarithm of the Hydronium ion concentration and the indictor changes color due to the dissociation of H ions. The lambda max is at 572 nm.

Properties and uses

The dissociation mechanism of chlorophenol red is similar to that of phenolphthalein meaning it can be used as a color indicator. The dissociation of hydroxyl and hydrogen atoms creates the dissociate scheme of chlorophenol red to change color from yellow to red. The pH properties of chlorophenol red are used to selectively determine the amount of chlorine dioxide in drinking water. Chlorophenol red selectively reacts with 0.1–1.9 mg/L chlorine dioxide at pH 7. The electrochemical properties of Chlorophenol red allows it to be a chromogenic label and can undergo oxidation creating several phenolic intermediates. The bacterial hydrolysis of a chlorophenol red labelled substrate produces chlorine retaining intermediates on electrodes.

References

  1. Haynes, p. 3.116
  2. Haynes, p. 8.88
  3. "pH Indicators". Chemistry LibreTexts. 2013-10-02. Retrieved 2021-03-14.
  4. "Chlorophenol Red".
  5. Hanai, Toshihiko (2016). "Quantitative Evaluation of Dissociation Mechanisms in Phenolphthalein and the Related Compounds". Journal of Computer Chemistry. 15: 13–21. doi:10.2477/jccj.2015-0055.
  6. Sweetin, Deborah L.; Sullivan, Elizabeth; Gordon, Gilbert (1996-01-01). "The use of chlorophenol red for the selective determination of chlorine dioxide in drinking water". Talanta. 43 (1): 103–108. doi:10.1016/0039-9140(95)01721-6. PMID 18966469.
  7. Casimero, Charnete; Bigham, Teri; McGlynn, Ruairi J.; Dooley, James S. G.; Ternan, Nigel G.; Snelling, William J.; Critchley, Megan E.; Zinkel, Cameron L.; Smith, Robert B.; Sabogal-Paz, Lyda P.; Davis, James (2019-12-01). "Electroanalytical properties of chlorophenol red at disposable carbon electrodes: Implications for Escherichia coli detection" (PDF). Bioelectrochemistry. 130: 107321. doi:10.1016/j.bioelechem.2019.06.006. PMID 31306878. S2CID 196813601.

Cited sources

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