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Phenolphthalein

CAS 77-09-8 · Formula C20H14O4 · MW 318.3 g/mol

A classic titration indicator that develops a pink endpoint in alkaline solution. It is used as an acid-base (pH) indicator over the approximate range 8.2 to 9.8 and as a laboratory and analytical reagent, turning colorless to pink across that transition.

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HS Code
2932.20
At a Glance
Material Family
Specialty Additives
Record Type
Pure compound
Primary Role
pH Adjustment
Solubility
< 1 mg/mL at 19 °C
Functional Roles
pH Adjustment
INCI Name
PHENOLPHTHALEIN
CosIng Functions
NOT REPORTED
Industries Served
Beauty & Personal Care Industrial Manufacturing Oil & Gas
Applications & Use Cases
  • ▸ pH indication: acid-base indicator for the pH 8.2 to 9.8 range
  • ▸ Titration: endpoint indicator for acid-base titrations
  • ▸ Analytical reagent: laboratory reagent for analytical chemistry
Physical Properties
Melting Point
496 to 262 °C
Density
1.299 at 25 °C
Solubility
< 1 mg/mL at 19 °C
Vapor Pressure
6.7X10-13 mm Hg @ 25 °C /Estimated/
Safety & Handling
Full SDS available on request

A grade-specific Safety Data Sheet (SDS) — with the complete hazard classification, handling precautions, and transport information — is supplied with every shipment and available on request. Confirm all safety and regulatory details against the SDS for your specific grade.

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HS / Tariff Classification
Harmonized System (HS) Code — 6-digit international heading
2932 . 20
Chapter 29
Organic chemicals
Heading 29.32
Internationally harmonized (WCO HS)
Subheading 2932.20
6-digit international code — national tariff line adds further digits
Chemical Identity
CAS Number
77-09-8
Molecular Formula
C20H14O4
Molecular Weight
318.3 g/mol
IUPAC Name
3,3-bis(4-hydroxyphenyl)-2-benzofuran-1-one
INCI Name
PHENOLPHTHALEIN
PubChem CID
4764
InChI Key
KJFMBFZCATUALV-UHFFFAOYSA-N
Synonyms & Trade Names
phenolphthalein Phthalimetten Euchessina Phenolax Phthalin Espotabs Purgophen Koprol Laxogen Trilax Purga Spulmako-lax Chocolax Purgen Dihydroxyphthalophenone Phenolphtaleine Correctol Medilax Colax
Full Description

Phenolphthalein (CAS 77-09-8) is a phthalein compound supplied as a white-to-pale powder. It is used as an acid-base (pH) indicator over the approximate range 8.2 to 9.8 and as a laboratory and analytical reagent, turning colorless to pink across that transition.

Frequently Asked Questions

What is phenolphthalein USP ACS powder used for?

Phenolphthalein (CAS 77-09-8) is a phthalein compound supplied as a white-to-pale powder. It is used as an acid-base (pH) indicator over the approximate range 8.2 to 9.8 and as an endpoint indicator in acid-base titrations and other analytical chemistry work.

What color change does phenolphthalein show?

Phenolphthalein is colorless under acidic conditions and turns pink across its transition range of approximately pH 8.2 to 9.8. This makes it a common endpoint indicator for acid-base titrations.

What is the chemical formula of phenolphthalein?

Phenolphthalein has the molecular formula C20H14O4, CAS 77-09-8, and is supplied here as USP/ACS-grade white-to-pale powder. The USP ACS designation indicates it meets those compendial/reagent grade conventions for analytical use.

How is phenolphthalein powder shipped?

Phenolphthalein carries HS code 2932.20 and is referenced under UN 1993 for transport classification purposes. Contact RawSource for available packaging and the SDS to confirm compliant shipping of the powder to your destination.

What is the cost of bulk phenolphthalein USP ACS powder?

Pricing depends on grade, purity, and quantity. Request a bulk quote with your required volume rather than relying on a list price, and we will return current pricing along with the CoA and SDS.

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Disclaimer. Information on this page — including properties, identifiers, hazard, transport (DOT/UN) and tariff (HS) classifications, and applications — is provided for general reference and is compiled from authoritative public sources (e.g. PubChem/ECHA, 49 CFR 172.101, the Harmonized Tariff Schedule). Values are typical and are not a guaranteed specification; the Certificate of Analysis (CoA) for the lot purchased governs. Products are sold for industrial and professional use only. Nothing here is a medical, health, or efficacy claim or advice. Always consult the current Safety Data Sheet (SDS) before handling, storage, transport or disposal, and confirm regulatory status, classification and suitability for your application and jurisdiction. Hazard, transport and tariff classifications must be verified for your specific shipment. RawSource makes no warranty, express or implied, and assumes no liability for use of this information. Trademarks. Third-party trademarks and brand names are the property of their respective owners; any reference is nominative — used only to identify a comparable product — and does not imply affiliation with, sponsorship by, or endorsement by the trademark owner.
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