76-59-5

Basic information

• Product Name: Bromothymol Blue
• Synonyms: 4,4’-(3h-2,1-benzoxathiol-3-ylidene)bis(2-bromo-3-methyl-6-(1-methylethyl)phen;6,6’-(3h-2,1-benzoxathiol-3-ylidene)bis(2-bromothymol)s,s-dioxide;dibromothymolsulphophthalein;ol)s,s-dioxide;yl)-,s,s-dioxide;3,3-BIS(3-BROMO-4-HYDROXY-5-ISOPROPYL-2-METHYLPHENYL)-2,1LAMBDA6-BENZOXATHIOLE-1,1(3H)-DIONE;3',3''-DIBROMOTHYMOLSULFONAPHTHALEIN;3',3''-DIBROMOTHYMOLSULFONEPHTHALEIN
• CAS NO: 76-59-5
• Molecular Formula: C₂₇H₂₈Br₂O₅S
• Molecular Weight: 624.38
• EINECS: 200-971-2
• Product Categories: Organics;Analytical Chemistry;Indicator (pH);pH Indicators;Indicator Solutions;Indicators;Titration;Sulfonephthalein
• Mol File: 76-59-5.mol
• Article Data: 2

Chemical Properties

• Melting Point: 204 °C
• Boiling Point: 614.3 °C at 760 mmHg
• Flash Point: 38 °C
• Appearance: Pink-brown to purple/Solid
• Density: 1.4668 (estimate)
• Vapor Pressure: 5.5E-17mmHg at 25°C
• Refractive Index: 1.634
• Storage Temp.: Store at RT.
• Solubility: Solubility Sparingly soluble in water, benzene; soluble in ethan
• PKA: 7.0, 7.1(at 25℃)
• Water Solubility: slightly soluble
• Stability: Stable. Incompatible with strong oxidizing agents.
• Merck: 14,1445
• BRN: 373934
• CAS DataBase Reference: Bromothymol Blue(CAS DataBase Reference)
• NIST Chemistry Reference: Bromothymol Blue(76-59-5)
• EPA Substance Registry System: Bromothymol Blue(76-59-5)

Safety Data

• Hazard Codes: Xn
• 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
• Hazardous Substances Data: 76-59-5(Hazardous Substances Data)

Usage

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

Different sources of media describe the Uses of 76-59-5 differently. You can refer to the following data:
1. Bromothymol blue is a chemical indicator for weak acids and bases.
2. 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.
3. 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.]

InChI:InChI=1/C27H28Br2O5S/c1-13(2)21-18(11-15(5)25(30)23(21)28)27(17-9-7-8-10-20(17)35(32,33)34-27)19-12-16(6)26(31)24(29)22(19)14(3)4/h7-14,30-31H,1-6H3

Synthetic route

thymol blue (76-61-9) → bromothymol blue (76-59-5)

Conditions	Yield
With bromine; acetic acid

2-[Bis-(3-bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-methyl]-benzenesulfonic acid; compound with triethyl-amine → bromothymol blue (76-59-5) + triethylamine (121-44-8)

Conditions	Yield
In acetonitrile at 25℃; Equilibrium constant; other solvents;

C27H28Br2O5S*C5H5N → bromothymol blue (76-59-5) + 2-{(3-Bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-[3-bromo-5-isopropyl-2-methyl-4-oxo-cyclohexa-2,5-dien-(Z)-ylidene]-methyl}-benzenesulfonic acid; compound with pyridine

Conditions	Yield
With pyridine In toluene Kinetics; Thermodynamic data; Arrhenius parameters, activation energy, various temp.;

C27H28Br2O5S*C6H7N → bromothymol blue (76-59-5) + 2-{(3-Bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-[3-bromo-5-isopropyl-2-methyl-4-oxo-cyclohexa-2,5-dien-(Z)-ylidene]-methyl}-benzenesulfonic acid; compound with 4-methyl-pyridine

Conditions	Yield
With picoline In toluene Kinetics;

C27H28Br2O5S*C9H7N → bromothymol blue (76-59-5) + 2-{(3-Bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-[3-bromo-5-isopropyl-2-methyl-4-oxo-cyclohexa-2,5-dien-(Z)-ylidene]-methyl}-benzenesulfonic acid; compound with quinoline

Conditions	Yield
With quinoline In toluene Kinetics;

bromine (7726-95-6) + thymol blue (76-61-9) + acetic acid (64-19-7) → bromothymol blue (76-59-5)

thymol (89-83-8) → bromothymol blue (76-59-5)

Conditions	Yield
Multi-step reaction with 2 steps 1: zinc chloride / 100 - 110 °C 2: glacial acetic acid; bromine View Scheme

4-carboxyphenylboronic acid (14047-29-1) + bromothymol blue (76-59-5) → 3'-[3-(3-bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-1,1-dioxo-1,3-dihydro-1λ6-benzo[c][1,2]oxathiol-3-yl]-6'-hydroxy-5'-isopropyl-2'-methyl-biphenyl-4-carboxylic acid

Conditions	Yield
With potassium phosphate; tetrabutylammomium bromide; palladium diacetate In N,N-dimethyl-formamide at 80℃; for 18h; Suzuki cross-coupling;	21%

pyridine (110-86-1) + bromothymol blue (76-59-5) → C27H28Br2O5S*C5H5N

Conditions	Yield
In toluene Rate constant;

picoline (108-89-4) + bromothymol blue (76-59-5) → C27H28Br2O5S*C6H7N

Conditions	Yield
In toluene Rate constant;

quinoline (91-22-5) + bromothymol blue (76-59-5) → C27H28Br2O5S*C9H7N

Conditions	Yield
In toluene Rate constant;

antipyrine (60-80-0) + bromothymol blue (76-59-5) → C27H28Br2O5S*C11H12N2O (111318-30-0)

Conditions	Yield
In dichloromethane at 15 - 40℃; Equilibrium constant; Thermodynamic data; detected by UV and conductivity; -ΔH, -ΔS and -ΔG;
In dichloromethane at 15℃; var. temp.;

bromothymol blue (76-59-5) + triethylamine (121-44-8) → 2-[Bis-(3-bromo-4-hydroxy-5-isopropyl-2-methyl-phenyl)-methyl]-benzenesulfonic acid; compound with triethyl-amine

Conditions	Yield
In acetonitrile at 25℃; Equilibrium constant; other solvents;

P,P'-(3-oxo-pentane-1,1-diyl)-bis-phosphonic acid tetraethyl ester (70508-87-1) + bromothymol blue (76-59-5) + benzylamine (100-46-9) → tetraethyl 3-benzylaminopentane-1,1-bisphosphonate

Conditions	Yield
With hydrogenchloride; potassium hydroxide; NaCNBH3; acetic acid In methanol; water

bromothymol blue (76-59-5) + clidinium bromide (3485-62-9) → Br(1-)*C22H26NO3(1+)*C27H28Br2O5S

Conditions	Yield
pH=3; aq. buffer;

bromothymol blue (76-59-5) + dequalinium chloride (522-51-0) → C27H28Br2O5S*C30H40N4(2+)*2Cl(1-)

Conditions	Yield
pH=9; aq. buffer;

bromothymol blue (76-59-5) + ketokonazole → C26H28Cl2N4O4*C27H28Br2O5S

Conditions	Yield
In aq. phosphate buffer pH=3;

bromothymol blue (76-59-5) + clotrimazole (23593-75-1) → C22H17ClN2*C27H28Br2O5S

Conditions	Yield
In aq. phosphate buffer pH=3;

bromothymol blue (76-59-5) + fluconazole (86386-73-4) → C13H12F2N6O*C27H28Br2O5S

Conditions	Yield
In aq. phosphate buffer pH=3;

bromothymol blue (76-59-5) + eszopiclone (138729-47-2) → C17H17ClN6O3*C27H28Br2O5S

Conditions	Yield
In aq. buffer Acidic conditions;

trihexyl(tetradecyl)phosphonium chloride (258864-54-9) + bromothymol blue (76-59-5) → 4,4′-(1,1-dioxido-3H-2,1-benzoxathiole-3,3-diyl)bis(2-bromo-6-isopropyl-3-methylphenol) trihexyltetradecylphosphonium salt

Conditions	Yield
In dichloromethane; water for 24h;

4-(5H-dibenzo[a,d]cyclohepten-5-ylidene)-1-methylpiperidine hydrochloride + bromothymol blue (76-59-5) → C27H28Br2O5S*C21H21N

Conditions	Yield
In aq. acetate buffer

bromothymol blue (76-59-5) → fluorobromothymol blue + difluorothymol blue

Conditions	Yield
With acetic acid for 0.0833333h;	A n/a B < 1 %Chromat.

4-Vinylphenylboronic acid (2156-04-9) + bromothymol blue (76-59-5) → C35H35BrO5S + C43H42O5S

Conditions	Yield
With potassium phosphate; tetrakis(triphenylphosphine) palladium(0) In ethanol; water at 80℃; Temperature; Reagent/catalyst; Suzuki Coupling;

bromothymol blue (76-59-5) + carbetapentane citrate (23142-01-0) → C20H31NO3*C27H28Br2O5S

Conditions	Yield
In chloroform; cyclohexane

Upstream product

• 76-61-9 thymol blue 
• 89-83-8 thymol 
• 7726-95-6 bromine 
• 64-19-7 acetic acid 

Downstream Products

• 111318-30-0 C₂₇H₂₈Br₂O₅S*C₁₁H₁₂N₂O 

Relevant articles and documents

A SPECTROPHOTOMETRIC STUDY OF SYSTEMS: SULFOPHTHALEIN DYES-TRIETHYLAMINE IN FOUR NON-AQUEOUS SOLVENTS

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