Bromothymol Blue Chemical Properties

Melting point:

200-202 °C (lit.)

Density 

1.4668 (estimate)

Flash point:

38 °C

storage temp. 

Store at +5°C to +30°C.

solubility 

Solubility Sparingly soluble in water, benzene; soluble in ethanol, ether; insoluble in petroleum ether

form 

Solid

pka

7.0, 7.1(at 25℃)

Boiling point:

614.3±55.0 °C(Predicted)

color 

Pink-brown to purple

PH Range

6(yellow)-7.6(blue)

PH

pH : 6.0～7.6

Odor

Characteristic odour

Water Solubility 

slightly soluble

λmax

420nm, 435nm, 620nm

Merck 

14,1445

BRN 

373934

Stability:

Stable. Incompatible with strong oxidizing agents.

Major Application

Sol-gel matrix, fuel cells, optical sensors, combustion gas detection system, paints, toys, cleaning products, detergents, textiles, food freshness sensor, identifying fresh and stale rice,wheat, detecting microorganisms, bacterial growth, psychoactive drug, dental materials

LogP

8.600 (est)

CAS DataBase Reference

76-59-5(CAS DataBase Reference)

EPA Substance Registry System

Bromothymol blue (76-59-5)

Safety Information

Hazard Codes 

Xn

Risk Statements 

10-41-36/37/38-20/21/22

Safety Statements 

24/25-39-26-36

RIDADR 

1170

WGK Germany 

3

RTECS 

SJ450000

TSCA 

Yes

HazardClass 

3

PackingGroup 

III

HS Code 

29349990

MSDS

• Language:English Provider:3',3"-Dibromothymolsulfonephthalein
• Language:English Provider:ACROS
• Language:English Provider:ALFA

Bromothymol Blue Usage And Synthesis

Description

Bromothymol blue is a pH indicator for weak acids and bases. In neutral solution, it appears bluish-green. At pH above 7.6 it appears blue, and at pH below 6.0 it appears yellow.
Bromothymol blue (BTB) is an anionic dye. It can be protonated or deprotonated to generate yellow or blue. BTB helps to make ion-pair complex, that is used to identify several pharmaceutical compounds with the help of extractive spectrophotometric methods.

Chemical Properties

Pale purple crystalline powder

Uses

Bromothymol blue is a chemical indicator for weak acids and bases.

Uses

Bromothymol blue is mostly used in measuring substances that would have relatively low acidic or basic levels (near a neutral pH). It's often used in pools, fish tanks, or measuring the presence of carbonic acid in a liquid.
Bromothymol Blue is a sulfonated hydroxyquinone in acidic solutions. In alkaline solutions, it is present as a dianion that is blue with a larger conjugated system than the yellow hydroxyquinone. Both forms are lipophilic. It is also known as bromthymol blue or dibromothymolsulfonphthalein.

Uses

Bromothymol Blue is a pH indicator used for measuring pH around 7 in pools and fish tanks. It operates in the pH range 6.0 to 7.6 due to the presence of an electron withdrawing and donating groups like bromine atoms and alkyl substitutents respectively. In the laboratory, it is used as a biological slide stain as well as used in obstetrics for detecting premature rupture of membranes. Further, it is used for the observation of photosynthetic activities and a respiratory indicator. In addition to this, it is used to define cell walls or nuclei under the microscope.

Application

Bromothymol blue has various applications in biology and medicine. It is suitable for demonstrating fungal hyphae within plant roots. It is used as a vital stain to trace the movement of fluids from the lymph. It is added to an agar gel microbial culture medium for enumeration of Bacillus cereus. Bromothymol blue is also used as a pH indicator due to its precise color transition properties at neutrality.
Suitable for use:
In preparations of pH indicator solutions.
In phospholipid staining on tissues and cells prepared on microscopy slides.

Preparation

Bromothymol blue is synthesized by adding elemental bromine to the thymol blue in a solution of glacial acetic acid.
To prepare a solution that is used as a pH indicator, we should dissolve 0.10 g in an 8.0 cm3 N/50 NaOH and then dilute it with water to 250 cm3. To prepare a solution used as an indicator in volumetric work, we should dissolve 0.1 g in the 100 cm3 of 50% (v/v) ethanol.

Definition

ChEBI: A member of the class of 2,1-benzoxathioles that is 2,1-benzoxathiole 1,1-dioxide in which both of the hydrogens at position 3 have been substituted by 3-bromo-4-hydroxy-5-isopropyl-2-methylphenyl groups.

General Description

Bromothymol blue is a pH indicator which is sparingly soluble in water, benzene but is soluble in ethanol. It is insoluble in petroleum ether. It has its major uses in Sol-gel matrix, fuel cells, optical sensors, combustion gas detection system. It is considered as a toxic reagent.

Purification Methods

Dissolved the dye in aqueous 5% NaHCO3 solution and precipitate it from the hot solution by dropwise addition of aqueous HCl. Repeat this until the extinction at max 420nm does not increase. It is an indicator: aqueous solutions are yellow at pH 6.0, and blue at pH 7.6. [Beilstein 19/3 V 461.]

Bromothymol Blue(76-59-5)Related Product Information

• METHYLTHYMOL BLUE
• Thymol
• Sulfosulfuron
• 2,3-Dibromopropionic acid
• Pralmorelin
• 5-Chlorovaleric acid
• Diphenolic acid
• Thymol Blue
• Chlorosulfonyl isocyanate
• Thymolphthalein
• DL-α-Tocopherol
• 1,3-Dibromopropane
• Phenylmethylsulfonyl fluoride
• Trypan Blue
• Thyme Oil
• 4-(Diethylamino)salicylaldehyde
• Bromophenol Blue
• BTB