P

Phthalic anhydride

IUPAC: 2-benzofuran-1,3-dione

C8H4O3 Organic Compounds CAS 85-44-9
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Quick Reference
Formula / NotationC8H4O3
CAS Number85-44-9
Molecular Weight148.11
Melting Point267.4 °F (NTP, 1992)
Boiling Point563 °F at 760 mmHg (sublimes) (NTP, 1992)
Density1.2 at 275 °F 1.53 at 20 °C (solid) (USCG, 1999) - Denser than water; will sink
SolubilityDecomposes (NTP, 1992)
AppearancePhthalic anhydride appears as a colorless to white lustrous solid in the form of needles with a mild distinctive odor. Moderately toxic by inhalation or ingestion and a skin irritant. Melting point...
Also Known As2-benzofuran-1,3-dione; 85-44-9; 1,3-Isobenzofurandione; 2-Benzofuran-1,3-dione; Phthalandione; Retarder esen; 1,3-Dioxophthalan; 1,3-Phthalandione; Phthalic acid anhydride; Retarder AK
CategoryOrganic Compounds

What is Phthalic anhydride?

Phthalic anhydride is the cyclic dicarboxylic anhydride that is the anhydride of phthalic acid. It has a role as an allergen. It is a cyclic dicarboxylic anhydride and a member of 2-benzofurans.

Formula & Notation

C8H4O3

IUPAC Name: 2-benzofuran-1,3-dione

Other Names / Synonyms: 2-benzofuran-1,3-dione; 85-44-9; 1,3-Isobenzofurandione; 2-Benzofuran-1,3-dione; Phthalandione; Retarder esen; 1,3-Dioxophthalan; 1,3-Phthalandione; Phthalic acid anhydride; Retarder AK

Properties & Characteristics

Appearance: Phthalic anhydride appears as a colorless to white lustrous solid in the form of needles with a mild distinctive odor. Moderately toxic by inhalation or ingestion and a skin irritant. Melting point.... Molecular formula: C8H4O3. Molecular weight: 148.11 g/mol. Boiling point: 563 °F at 760 mmHg (sublimes) (NTP, 1992). Melting point: 267.4 °F (NTP, 1992). Density: 1.2 at 275 °F 1.53 at 20 °C (solid) (USCG, 1999) - Denser than water; will sink. Solubility: Decomposes (NTP, 1992). Vapor pressure: 0.0002 mmHg at 68 °F ; 0.001 mmHg at 86 °F (NTP, 1992). LogP: 1.3.

Physical Data

PropertyValue
Melting Point267.4 °F (NTP, 1992)
Boiling Point563 °F at 760 mmHg (sublimes) (NTP, 1992)
Density1.2 at 275 °F 1.53 at 20 °C (solid) (USCG, 1999) - Denser than water; will sink
Molecular Weight148.11
SolubilityDecomposes (NTP, 1992)
AppearancePhthalic anhydride appears as a colorless to white lustrous solid in the form of needles with a mild distinctive odor. Moderately toxic by inhalation or ingestion and a skin irritant. Melting point...

Uses & Applications

Used as an industrial feedstock, solvent, pharmaceutical intermediate, flavoring agent, or chemical building block.

Safety Information

Flammable or irritant. Many organic compounds are flammable liquids or vapours. Keep away from ignition sources. Consult SDS for specific hazard data.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Phthalic anhydride
Formula C8H4O3
CAS Number 85-44-9
Molecular Weight 148.11
Synonyms 2-benzofuran-1,3-dione; 85-44-9; 1,3-Isobenzofurandione; 2-Benzofuran-1,3-dione; Phthalandione; Retarder esen; 1,3-Dioxophthalan; 1,3-Phthalandione; Phthalic acid anhydride; Retarder AK

Frequently Asked Questions

Phthalic anhydride is the cyclic dicarboxylic anhydride that is the anhydride of phthalic acid. It has a role as an allergen. It is a cyclic dicarboxylic anhydride and a member of 2-benzofurans.

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Editorial standards: Chemical data is sourced from peer-reviewed literature, CAS Registry, NIST WebBook, and PubChem. Safety information reflects guidance from OSHA, ECHA, and IAEA. For educational purposes only — always consult official SDS documentation and qualified professionals before handling chemicals.