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Merck

105945

Sigma-Aldrich

Phenolphthalein

ACS reagent

Synonym(s):

3,3-Bis(4-hydroxyphenyl)-1(3H)-isobenzofuranone

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About This Item

Empirical Formula (Hill Notation):
C20H14O4
CAS Number:
77-09-8
Molecular Weight:
318.32
Colour Index Number:
764
Beilstein:
284423
EC Number:
201-004-7
MDL number:
MFCD00005913
UNSPSC Code:
12171500
PubChem Substance ID:
24846716
NACRES:
NA.47

Key Documents

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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

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.

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Pictograms

Health hazardExclamation mark
GHS08,GHS07

Signal Word

Danger

Hazard Statements

H315,H341,H350,H361f

Hazard Classifications

Carc. 1B - Muta. 2 - Repr. 2 - Skin Irrit. 2

Storage Class Code

6.1C - Combustible acute toxic Cat.3 / toxic compounds or compounds which causing chronic effects

WGK

WGK 3

Flash Point(F)

Not applicable

Flash Point(C)

Not applicable

Personal Protective Equipment

dust mask type N95 (US), Eyeshields, Gloves

Regulatory Listings

Regulatory Listings are mainly provided for chemical products. Only limited information can be provided here for non-chemical products. No entry means none of the components are listed. It is the user’s obligation to ensure the safe and legal use of the product.

EU REACH SVHC Candidate List

CAS No.

EU REACH Annex XVII (Restriction List)

CAS No.

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Certificates of Analysis (COA)

Lot/Batch Number
BCCH0227
BCCH0226
BCCD0098
MKCL5195
MKCK5943

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