Chlorophenol red

Chlorophenol red
Names
	Preferred IUPAC name 3,3-Bis(3-chloro-4-hydroxyphenyl)-2,1λ6-benzoxathiole-1,1(3H)-dione
	Other names 3′,3′-Dichlorophenolsulfonaphthalein
Identifiers
CAS Number	4430-20-0 ;
3D model (JSmol)	Interactive image;
ChemSpider	19293 ;
ECHA InfoCard	100.022.382
EC Number	224-619-2;
PubChem CID	20486;
UNII	P3S5KH33EA ;
CompTox Dashboard (EPA)	DTXSID4063450 ;
	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/h1-10,22-23H Key: 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/h1-10,22-23H Key: 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−1
Melting point	261 °C (502 °F; 534 K)
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

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.^[2] 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.^[3] The lambda max is at 572 nm.^[4]

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.^[5] 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.^[6] 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.^[7]

References

^ Haynes, p. 3.116
^ Haynes, p. 8.88
^ "pH Indicators". Chemistry LibreTexts. 2013-10-02. Retrieved 2021-03-14.
^ "Chlorophenol Red".
^ 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.
^ 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.
^ 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

Haynes, William M., ed. (2016). CRC Handbook of Chemistry and Physics (97th ed.). CRC Press. ISBN 9781498754293.

[crc-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.

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