105945

Phenolphthalein

ACS reagent

• Synonym(s): 3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone
• Empirical Formula (Hill Notation): C₂₀H₁₄O₄
• CAS Number: 77-09-8
• Molecular Weight: 318.32
• Colour Index Number: 764
• Beilstein/REAXYS Number: 284423
• EC Number: 201-004-7
• MDL number: MFCD00005913
• UNSPSC Code: 12171500
• PubChem Substance ID: 24846716
• NACRES: NA.47

Properties

• grade: ACS reagent
• Quality Level: 200
• form: powder
• technique(s): titration: suitable
• visual transition interval: 8.0-10, colorless to red
• mp: 261-263 °C (lit.)
• solubility: acetone: soluble
• density: 1.27 g/cm³ at 32 °C
• λmax: 374 nm (2nd); 552 nm
• application(s): diagnostic assay manufacturing; hematology; histology
• storage temp.: room temp
• SMILES string: Oc1ccc(cc1)C2(OC(=O)c3ccccc23)c4ccc(O)cc4
• InChI: 1S/C20H14O4/c21-15-9-5-13(6-10-15)20(14-7-11-16(22)12-8-14)18-4-2-1-3-17(18)19(23)24-20/h1-12,21-22H
• InChI key: KJFMBFZCATUALV-UHFFFAOYSA-N

Description

General description

Phenolphthalein is an indicator for acid-base titration reactions. It changes from colorless to violet-red between pH 8.3-9.8, it is red in extremely acidic solutions, and colorless in extremely alkaline solutions.

It is present as a nonionic, lipophilic lactone in aqueous neutral solutions. It exists as a hydrophilic dianion in alkaline solutions.

Application

Phenolphthalein has been commonly used as an indicator in the fields of biology and medicine. Its applications include:

• the development of novel technique to monitor the vacuum freeze-drying process
• the determination of the depth of carbonation in concrete
• the utilization of liquid marbles to sense gaseous environmental components
• the estimation of total acidity in vinegar
• the assessment of sodium hydroxide penetration into potatoes following chemical peeling
• as a model organic compound in the evaluation of the capture efficiency of various cyclodextrin constructs such as nanofiber-CD

Biochem/physiol Actions

Phenolphthalein is colorless in acidic solutions and turns pink in basic solutions.

Principle

Phenolphthalein undergoes structural modification when there is a change in pH or in the structural state of water. It is a nonionic, lipophilic colorless lactone in aqueous neutral solutions and a hydrophilic dianion in alkaline solutions.

Safety Information

• pictograms: GHS08,GHS07
• signalword: Danger
• hcodes: H315,H341,H350,H361f
• pcodes: P202 - P264 - P280 - P302 + P352 - P308 + P313 - P332 + P313
• Hazard Classifications: Carc. 1B - Muta. 2 - Repr. 2 - Skin Irrit. 2
• Storage Class: 6.1C - Combustible acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects
• wgk_germany: WGK 3
• flash_point_f: Not applicable
• flash_point_c: Not applicable
• ppe: Eyeshields, Gloves, type P3 (EN 143) respirator cartridges