Thymol blue

Last updated
Thymol blue
Thymolblau skeletal.png
Thymol Blue crystals.jpg
Names
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
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.000.886
PubChem CID
UNII
Properties
C27H30O5S
Molar mass 466.59 g·mol−1
AppearanceBrownish-green crystal powder
Melting point 221–224 °C (430–435 °F; 494–497 K)
decomposes [1]
Insoluble
UV-vismax)594 nm (1st)
376 nm (2nd) [1]
Hazards
Main hazards Harmful
Hazard X.svg Xn Hazard N.svg N
NFPA 704 (fire diamond)
Flammability code 1: Must be pre-heated before ignition can occur. Flash point over 93 °C (200 °F). E.g. canola oilHealth code 1: Exposure would cause irritation but only minor residual injury. E.g. turpentineReactivity (yellow): no hazard codeSpecial hazards (white): no codeThymol blue
1
1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
X mark.svgN  verify  (what is  Yes check.svgYX mark.svgN ?)
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.

Contents

Thymol blue(pH indicator)
below pH 8.0above pH 9.6
8.09.6
Thymol blue(pH indicator)
below pH 1.2above pH 2.8
1.22.8

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. [2]

Structures

Thymol blue has different structures at different pH.

Thymolblau.png thymol blue.
Color of thymol blue solution at different acid-base conditions: left: acidic, middle: neutral, right: alkaline Color change of thymol blue at different pH.jpg
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%. [3]

Bibliography

Related Research Articles

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Ultraviolet–visible spectroscopy Range of spectroscopic analysis

Ultraviolet–visible spectroscopy or ultraviolet–visible spectrophotometry refers to absorption spectroscopy or reflectance spectroscopy in part of the ultraviolet and the full, adjacent visible spectral regions. This means it uses light in the visible and adjacent ranges. The absorption or reflectance in the visible range directly affects the perceived color of the chemicals involved. In this region of the electromagnetic spectrum, atoms and molecules undergo electronic transitions. Absorption spectroscopy is complementary to fluorescence spectroscopy, in that fluorescence deals with transitions from the excited state to the ground state, while absorption measures transitions from the ground state to the excited state.

Bromothymol blue chemical compound

Bromothymol blue is a pH indicator. It is mostly used in applications that require measuring substances that would have a relatively neutral pH. A common use is for measuring the presence of carbonic acid in a liquid. It is typically sold in solid form as the sodium salt of the acid indicator.

Spectrophotometry deals with visible light, near-ultraviolet, and near-infrared, but does not cover time-resolved spectroscopic techniques

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Isosbestic point specific wavelength, wavenumber or frequency at which the total absorbance of a sample does not change during a chemical reaction or a physical change of the sample

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Fluorophore agents that emit light after excitation by light

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Coomassie Brilliant Blue cbb r250

Coomassie Brilliant Blue is the name of two similar triphenylmethane dyes that were developed for use in the textile industry but are now commonly used for staining proteins in analytical biochemistry. Coomassie Brilliant Blue G-250 differs from Coomassie Brilliant Blue R-250 by the addition of two methyl groups. The name "Coomassie" is a registered trademark of Imperial Chemical Industries.

Bromophenol blue chemical compound

Bromophenol blue is used as a pH indicator, a electrophoretic color marker, and a dye. It can be prepared by slowly adding excess bromine to a hot solution of phenolsulfonphthalein in glacial acetic acid.

Thymol Chemical compound found in plants including thyme

Thymol (also known as 2-isopropyl-5-methylphenol, IPMP) is a natural monoterpenoid phenol derivative of cymene, C10H14O, isomeric with carvacrol, found in oil of thyme, and extracted from Thymus vulgaris (common thyme), Ajwain and various other kinds of plants as a white crystalline substance of a pleasant aromatic odor and strong antiseptic properties. Thymol also provides the distinctive, strong flavor of the culinary herb thyme, also produced from T. vulgaris.

Thymolphthalein chemical compound

Thymolphthalein is a phthalein dye used as an acid–base (pH) indicator. Its transition range is around pH 9.3–10.5. Below this pH, it is colorless; above, it is blue. The molar extinction coefficient for the blue thymolphthalein dianion is 38,000 M−1 cm−1 at 595 nm.

Universal indicator type of pH indicator

To judge how strong a given acid or base is, a universal indicator is used, which is a mixture of several indicators. A universal indicator is a pH indicator made of a solution of several compounds that exhibits several smooth colour changes over a wide range pH values to indicate the acidity or alkalinity of solutions. Although there are several commercially available universal pH indicators, most are a variation of a formula patented by Yamada in 1933. Details of this patent can be found in Chemical Abstracts. Experiments with Yamada's universal indicator are also described in the Journal of Chemical Education.

Phenol red chemical compound

Phenol red is a pH indicator frequently used in cell biology laboratories.

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Dansyl chloride chemical compound

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Brookers merocyanine chemical compound

Brooker's merocyanine is an organic dye belonging to the class of merocyanines.

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Thiosulfate-citrate-bile salts-sucrose agar, or TCBS agar, is a type of selective agar culture plate that is used in microbiology laboratories to isolate Vibrio species. TCBS agar is highly selective for the isolation of V. cholerae and V. parahaemolyticus as well as other Vibrio species. TCBS agar contains high concentrations of sodium thiosulfate and sodium citrate to inhibit the growth of Enterobacteriaceae. Inhibition of Gram-positive bacteria is achieved by the incorporation of ox gall, which is a naturally occurring substance containing a mixture of bile salts and sodium cholate, a pure bile salt. Sodium thiosulfate also serves as a sulfur source and its presence, in combination with ferric citrate, allows for the easy detection of hydrogen sulfide production. Saccharose (sucrose) is included as a fermentable carbohydrate for metabolism by Vibrio species. The alkaline pH of the medium enhances the recovery of V. cholerae and inhibits the growth of others. Thymol blue and bromothymol blue are included as indicators of pH changes.

Distributed Bragg reflector laser

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References

  1. 1 2 Thymol Blue
  2. "Product Specification: Thymol Blue- ACS reagent" (PDF). Sigma-Aldrich. 9 October 2017. p. 1.
  3. "Thymol blue". PubChem. Retrieved 2017-10-09.