BTB

Synonym(s):3′,3′′-dibromothymolsulfonephthalein sodium salt;3,3`-Dibromothylmolsulfonphthalein Sodium Salt;Bromothymol blue sodium salt;Bromothymol Blue, Sodium Salt;Bromthymol Blue sodium salt

CAS NO.：34722-90-2
Empirical Formula: C27H29Br2NaO5S
Molecular Weight: 648.38
MDL number: MFCD00077263
EINECS: 252-169-7
SAFETY DATA SHEET (SDS)
Update Date: 2026-05-28 00:35:15

What is BTB?

Chemical properties

Dark greenish gold crystalline powder

The Uses of BTB

It is employed as a pH indicator which is yellow at pH ? 6.0 and blue at pH ? 7.6. It finds its major application in lithium battery, textiles and antagonists.

The Uses of BTB

Suitable for use:

In preparations of pH indicator solutions
In phospholipid staining on tissues and cells prepared on microscopy slides

The Uses of BTB

Bromothymol Blue sodium salt has been used as a pH indicator in the yeast growth media (YPD, yeast extract peptone dextrose).

What are the applications of Application

Bromothymol blue sodium salt is a pH indicator which is yellow at pH ≤ 6.0 and blue at pH ≥ 7.6

General Description

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.

Biochem/physiol Actions

Bromothymol Blue is a pH-indicator. It is also used for carbonic anhydrase assay due to the conversion of carbon dioxide to bicarbonate.

Properties of BTB

Melting point:	200-202°C
Density	0.990
storage temp.	room temp
solubility	Solubility Soluble in water, ethanol
form	Powder
pka	7.0, 7.1(at 25℃)
color	Orange-brown to dark green
Odor	Characteristic odour
PH Range	Yellow (6.0) to blue (7.6)
Water Solubility	SOLUBLE
λmax	615nm, 392nm
BRN	6887926
Stability:	Stable. Incompatible with strong oxidizing agents.
Major Application	Lithium battery, textiles, antagonists
CAS DataBase Reference	34722-90-2(CAS DataBase Reference)
EPA Substance Registry System	Phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[2-bromo-3-methyl-6-(1-methylethyl)-, monosodium salt (34722-90-2)

Safety information for BTB

Signal word	Warning
Pictogram(s)	Exclamation Mark Irritant GHS07
GHS Hazard Statements	H315:Skin corrosion/irritation H319:Serious eye damage/eye irritation H335:Specific target organ toxicity, single exposure;Respiratory tract irritation
Precautionary Statement Codes	P261:Avoid breathing dust/fume/gas/mist/vapours/spray. P271:Use only outdoors or in a well-ventilated area. P280:Wear protective gloves/protective clothing/eye protection/face protection.