Phenolphthalein

Phenolphthalein

Phenolphthalein sample (middle), and dissolved in an acid (left) and a base (right).
Names
IUPAC name 3,3-bis(4-hydroxyphenyl)isobenzofuran-1(3H)-one
Systematic IUPAC name Phenolphthalein
Other names HIn phph
Identifiers
Jmol-3D images	Image
SMILES O=C1OC(c2ccccc12)(c3ccc(O)cc3)c4ccc(O)cc4
Properties
Chemical formula	C20H14O4
Molar mass	318.33 g/mol
Appearance	White powder
Density	1.3 g/cm3 (at 20 °C)
Melting point	262.5 °C (504.5 °F; 535.6 K)
Boiling point	Decomposes
Solubility in water	400 mg/L
Solubility	Very soluble in acetone, ethanol and pyrene Soluble in chloroform, diethyl ether, and toluene Slightly soluble in carbon disulfide Insoluble in benzene, hexane, petroleum ether
Vapor pressure	6.7·10-13 mm Hg at 25 °C
Hazards
Safety data sheet	Acros Organics
Flash point	Non-flammable
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Phenolphthalein is an organic chemical compound, often used as an indicator in acid–base titrations. For this application, it turns colorless in acidic solutions and pink in basic solutions.

Properties

Physical

Phenolphthalein is a white solid, poorly soluble in water but very soluble in ethanol.

Availability

Phenolphthalein is sold by various chemical suppliers.

Preparation

Phenolphthalein can be prepared by reacting phenol with phthalic anhydride, in the presence of anhydrous aluminium chloride and zinc chloride. Thionyl chloride can substitute aluminium chloride.

Projects

• Base indicator

Handling

Safety

Phenolphthalein, if taken orally, is mildly toxic and a powerful laxative. Several decades ago, it was commonly used as such in medicine. Today, less toxic laxatives are used.

References

Relevant Sciencemadness threads

• Phenolphthalein Decomposition
• Phenolphthalein ( 3,3-bis(4-hydroxyphenyl)isobenzofuran-1(3H)-one ), h2so4 and h2o2