Bromocresol Purple

Description

Bromocresol Purple · CAS 115-40-2 · C21H16Br2O5S. UNII 201C22C3EC. Melting Point: 241.5 °C; Dissociation Constants: pKa = 6.3.

Identification

CAS Registry Number	115-40-2
PubChem CID	8273
Molecular formula	C21H16Br2O5S
IUPAC name	2-bromo-4-[3-(3-bromo-4-hydroxy-5-methylphenyl)-1,1-dioxo-2,1λ6-benzoxathiol-3-yl]-6-methylphenol
UNII (FDA)	201C22C3EC

Computed Descriptors

Molecular Weight	540.2
XLogP3	5.1
Hydrogen Bond Donor Count	2
Hydrogen Bond Acceptor Count	5
Rotatable Bond Count	2
Exact Mass	539.90647
Monoisotopic Mass	537.90852
Topological Polar Surface Area	92.2
Heavy Atom Count	29
Formal Charge	0

Physical & Chemical Properties

Melting Point	241.5 °C
Dissociation Constants	pKa = 6.3

Physical description & handling notes

• Odorless, pale-yellow to purple solid; Available as pure compound, monosodium salt, and dilute solutions; [CHEMINFO]
• Minute, slightly yellow crystals
• Soluble in alcohol, dilute alkalies

Regulatory Status

GHS notification summary	6.9% (7 / 101)

GHS Hazard Classification

GHS notification summary	6.9% (7 / 101)
Reported hazard statements	H315 (93.1%), H319 (93.1%), H335 (92.1%)

Documented Uses

• A sulfonphthalein dye used as a pH indicator; [CHEMINFO] Used as a pH indicator for the pH range of 5.2-6.8 and 10.2-11.8; [Ullmann]
• As indicator, pH 5.2 yellow; pH 6.8 purple
• Prepared by treating o-cresol red with bromine in glacial acetic acid.
• Phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[2-bromo-6-methyl-: ACTIVE

Synonyms

Bromocresol purple; 115-40-2; BROMCRESOL PURPLE; DTXSID3059428; HSDB 7729; 201C22C3EC; NSC-374134; Phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis[2-bromo-6-methyl-; CHEBI:86154; Phenol, 4,4'-(1,1-dioxido-3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-methyl-; Purple, Bromcresol; Purple, Bromocresol; RefChem:121504; DTXCID8033354; Phenol, 4,4'-(3H-2,1-benzoxathiol-3-ylidene)bis(2-bromo-6-methyl)-, S,S-dioxide; 204-087-8

Frequently Asked Questions

What are the CAS number and molecular formula of Bromocresol Purple?

CAS 115-40-2; molecular formula C21H16Br2O5S; molecular weight — g/mol.

What other names is Bromocresol Purple known by?

Bromocresol purple, 115-40-2, BROMCRESOL PURPLE, DTXSID3059428, HSDB 7729, 201C22C3EC.

Is Bromocresol Purple classified as hazardous?

6.9% of GHS notifications report no hazard classification (7 of 101).

What are the key physical properties of Bromocresol Purple?

Melting Point: 241.5 °C; Dissociation Constants: pKa = 6.3.

Facts on this page are taken from PubChem (US National Library of Medicine) and Wikidata. Grade-specific data — assay, moisture, particle size, packaging, shelf life — is issued per batch on the COA and is not published here.