Bromocresol purple
| Names | |
|---|---|
| IUPAC name
3,3-Bis(3-bromo-4-hydroxy-5-methylphenyl)-2,1λ6-benzoxathiole-1,1(3H)-dione
| |
| Other names
5′,5′′-Dibromo-o-cresolsulfonephthalein
BCP Bromcresol purple | |
| Properties | |
| C21H16Br2O5S | |
| Molar mass | 540.22 g/mol |
| Appearance | Brown or purple solid |
| Odor | Odorless |
| Melting point | 241–242 °C (466–468 °F; 514–515 K) (decomposes) |
| Boiling point | Decomposes |
| 0.1 g/100 ml | |
| Solubility | Soluble in alcohols |
| Solubility in ethanol | 8 g/100 ml |
| Solubility in methanol | 0.4 g/100 ml |
| Solubility in methyl cellosolve | 30 g/100 ml |
| Vapor pressure | ~0 mmHg |
| Hazards | |
| Safety data sheet | Sigma-Aldrich |
| Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). | |
| Infobox references | |
Bromocresol purple (BCP) or 5′,5″-dibromo-o-cresolsulfophthalein, is an organic chemical compound, a dye of the triphenylmethane family (triarylmethane dyes) and a pH indicator. It is colored yellow below pH 5.2, and violet above pH 6.8.
Contents
Properties
Chemical
At pH below pH 5.2, solutions of bromocresol purple turn yellow, while above pH 6.8, they turn violet. Changing the level of acidity causes a shift in the equilibrium between two different structures that have different colors. In near-neutral or alkaline solution, the chemical has a sulfonate structure that gives the solution a purple color. As the pH decreases, it converts to a sultone (cyclic sulfonic ester) that colors the solution yellow.
Physical
Bromcreson purple is a purple-ish solid, slightly soluble in water.
Availability
Can be bought from chemical suppliers.
Preparation
Delete this section if not applicable
Projects
- pH indicator
- Biological stain for cells
- Determination of serum albumin concentration
Handling
Safety
Bromocresol purple doesn't appear to be toxic, but it may be irritant.
Storage
In closed bottles, away from air and light.
Disposal
No special disposal is required.
