Misplaced Pages

Thymol blue

Article snapshot taken from Wikipedia with creative commons attribution-sharealike license. Give it a read and then ask your questions in the chat. We can research this topic together.
(Redirected from Thymolsulfonephthalein)
Thymol blue
Names
Preferred IUPAC name 3,3-Bis-2,1λ-benzoxathiole-1,1(3H)-dione
Other names α-hydroxy-α,α-bis(5-hydroxycarvacryl)- o-toluenesulfonic acid γ-sultone; thymolsulfonephthalein
Identifiers
CAS Number
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.886 Edit this at Wikidata
EC Number
  • 200-973-3
PubChem CID
UNII
CompTox Dashboard (EPA)
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,1-6H3Key: PRZSXZWFJHEZBJ-UHFFFAOYSA-N
  • 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,1-6H3Key: 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
Appearance Brownish-green crystal powder
Melting point 221–224 °C (430–435 °F; 494–497 K)
decomposes
Solubility in water Insoluble
UV-vis (λmax) 594 nm (1st)
376 nm (2nd)
Hazards
Occupational safety and health (OHS/OSH):
Main hazards Harmful
GHS labelling:
Pictograms GHS07: Exclamation mark
Signal word Warning
Hazard statements H302
Precautionary statements P264, P270, P301+P312, P330, P501
NFPA 704 (fire diamond)
NFPA 704 four-colored diamondHealth 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineFlammability 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilInstability (yellow): no hazard codeSpecial hazards (white): no code
1 1
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

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.

Structures

Thymol blue has different structures at different pH.

thymol blue.
Color of thymol blue solution at different acid-base conditions: left: acidic, middle: neutral, right: alkaline

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%.

Bibliography

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

References

  1. ^ Thymol Blue
  2. "Thymol blue". pubchem.ncbi.nlm.nih.gov. Retrieved 12 December 2021.
  3. "Product Specification: Thymol Blue- ACS reagent" (PDF). Sigma-Aldrich. 9 October 2017. p. 1.
  4. "Thymol Blue MSDS". Fisher Scientific. Retrieved 2024-07-23.
  5. "Thymol blue". PubChem. Retrieved 2017-10-09.

External links

Categories: