Thymol blue

Thymol blue
Names


Preferred IUPAC name 3,3-Bis[4-hydroxy-2-methyl-5-(propan-2-yl)phenyl]-2,1λ⁶-benzoxathiole-1,1(3H)-dione
Other names α-hydroxy-α,α-bis(5-hydroxycarvacryl)- o-toluenesulfonic acid γ-sultone; thymolsulfonephthalein
Identifiers
CAS Number	76-61-9^Y
3D model (JSmol)	Interactive image
ChemSpider	59008^Y
ECHA InfoCard	100.000.886
EC Number	200-973-3
PubChem CID	65565
UNII	8YB4804L4M^Y
CompTox Dashboard (EPA)	DTXSID5058800
InChI InChI=1S/C27H30O5S/c1-15(2)19-13-22(17(5)11-24(19)28)27(21-9-7-8-10-26(21)33(30,31)32-27)23-14-20(16(3)4)25(29)12-18(23)6/h7-16,28-29H,1-6H3^Y Key: PRZSXZWFJHEZBJ-UHFFFAOYSA-N^Y InChI=1/C27H30O5S/c1-15(2)19-13-22(17(5)11-24(19)28)27(21-9-7-8-10-26(21)33(30,31)32-27)23-14-20(16(3)4)25(29)12-18(23)6/h7-16,28-29H,1-6H3 Key: PRZSXZWFJHEZBJ-UHFFFAOYAE
SMILES O=S2(=O)OC(c1ccccc12)(c3cc(c(O)cc3C)C(C)C)c4cc(c(O)cc4C)C(C)C
Properties
Chemical formula	C₂₇H₃₀O₅S
Molar mass	466.59 g·mol⁻¹
Appearance	Brownish-green crystal powder
Melting point	221–224 °C (430–435 °F; 494–497 K) decomposes^[1]
Solubility in water	Insoluble
UV-vis (λ_max)	594 nm (1st) 376 nm (2nd)^[1]
Hazards
Occupational safety and health (OHS/OSH):
Main hazards	Harmful
GHS labelling:^[2]
Pictograms
Signal word	Warning
Hazard statements	H302
Precautionary statements	P264, P270, P301+P312, P330, P501
NFPA 704 (fire diamond)	1 1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). N verify (what is ^YN ?) Infobox references

Thymol blue (thymolsulfonephthalein) is a brownish-green or reddish-brown crystalline powder that is used as a pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions.

Thymol blue (pH indicator)
below pH 8.0		above pH 9.6
8.0	⇌	9.6

Thymol blue (pH indicator)
below pH 1.2		above pH 2.8
1.2	⇌	2.8

It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue at pH 8.0–9.6. It is usually a component of Universal indicator.

At wavelength (378 - 382) nm, extinction coefficient > 8000 and at wavelength (298 - 302) nm , the extinction coefficient > 12000.^[3]

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Transcription

Structures

Thymol blue has different structures at different pH.

thymol blue.

Safety

It may cause irritation. Its toxicological properties have not been fully investigated. Harmful if swallowed, Acute Toxicity. Only Hazardous when percent values are above 10%.^[4]

Bibliography

Merck. "Thymol Blue." The Merck Index. 14th ed. 2006. Accessed via web on 2007-02-25.

References

^ ^a ^b Thymol Blue
^ "Thymol blue". pubchem.ncbi.nlm.nih.gov. Retrieved 12 December 2021.
^ "Product Specification: Thymol Blue- ACS reagent" (PDF). Sigma-Aldrich. 9 October 2017. p. 1.
^ "Thymol blue". PubChem. Retrieved 2017-10-09.

External links

Wikimedia Commons has media related to Thymol blue.

PubChem entry

This page was last edited on 12 December 2021, at 22:42

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