Thymol blue

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Thymol blue
IUPAC name 4-[9-(4-hydroxy-2-methyl-5-propan- 2-yl-phenyl)-7,7-dioxo-8-oxa- 7λ6-thiabicyclo[4.3.0]nona-1,3,5-trien-9-yl]- 5-methyl-2-propan-2-yl-phenol
Other names α-hydroxy-α,α-bis(5-hydroxycarvacryl)- o-toluenesulfonic acid γ-sultone; thymolsulfonephthalein
Identifiers
CAS number [76-61-9]
Properties
Molecular formula C27H30O5S
Molar mass 466.59[1] g mol−1
Appearance Brownish-green crystal powder
Solubility in water Insoluble
Except where noted otherwise, data are given for
materials in their standard state
(at 25 °C, 100 kPa)
Infobox disclaimer and references

Thymol blue is a brownish-green crystal powder that is used as an pH indicator. It is insoluble in water but soluble in alcohol and dilute alkali solutions. It transitions from red to yellow at pH 1.2–2.8 and from yellow to blue from at pH 8.0–9.6.

Structures of thymol blue at different pH
Structures of thymol blue at different pH

[edit] Bibliography

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

[edit] References

  1. ^ Number derived from molecular weight

[edit] External links


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