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Molecule record

PHTHALIC ANHYDRIDE

C8H4O3

148.11 g/mol

2D structure for PHTHALIC ANHYDRIDE

Molecular properties

Formula
C8H4O3
Molar mass
148.11 g·mol−1
Exact mass
148.0160 Da
7
0
3
43.40 Ų
1.3 (PubChem computed XLogP3-AA descriptor)
CAS
85-44-9
PubChem CID
6811

Interactions

Polarity
Often polar; exact polarity depends on size, substitution, and ionization state.
Acid-base behavior
Review ionizable groups and pKa data where available; ChemForge does not infer definitive acid-base state from identity alone.
Intermolecular forces
Assess dispersion, dipole interactions, hydrogen bonding, and ionic character from the functional groups shown.

Functional groups

Alkene
Aromatic ring
Ester
Phenol

Physical properties

PropertyValueConditionsSource
Logp1.3PubChem computed XLogP3-AA descriptorPubChem(link only)

Common names and synonyms

  • 1,2-Benzenedicarboxylic acid anhydride
  • 1,2-Benzenedicarboxylic anhydride
  • 1,3-Dioxophthalan
  • 1,3-Isobenzofurandione
  • 1,3-Phthalandione
  • 2-Benzofuran-1,3-dione
  • 85-44-9
  • Anhydride phtalique
Show all 22 synonyms
  • Anidride ftalica
  • ESEN
  • Ftaalzuuranhydride
  • Ftalanhydrid
  • Ftalowy bezwodnik
  • Phthalandione
  • Phthalic acid anhydride
  • Phthalsaeureanhydrid
  • Retarder AK
  • Retarder PD
  • Retarder esen
  • Vulkalent B
  • Vulkalent B/C
  • o-Phthalic acid anhydride

Structure identifiers

Canonical SMILES
C1=CC=C2C(=C1)C(=O)OC2=O
Isomeric SMILES
C1=CC=C2C(=C1)C(=O)OC2=O
InChI
InChI=1S/C8H4O3/c9-7-5-3-1-2-4-6(5)8(10)11-7/h1-4H
InChIKey
LGRFSURHDFAFJT-UHFFFAOYSA-N
PubChem CID
6811

Spectroscopy

Tabs appear only for spectra stored with clear provenance.

Open library

IR spectrum

ChemArche Original Educational Content(redistributable)

Simulated FTIR trace

Predicted FTIR / %T

4 cm-1 resolution / deterministic instrument profile

Hover for cursor
4000350030002500200015001000500100500wavenumber (cm−1)transmittance (%)

Peak assignments

3350 cm−1broad O-H (simulated)
1740 cm−1C=O ester (simulated)
1180 cm−1C-O ester (simulated)
1645 cm−1C=C alkene (simulated)
3030 cm−1aromatic C-H (simulated)
1600 cm−1aromatic C=C (simulated)
2960 cm−1sp3 C-H (simulated)

Simulated NMR

On-demand educational prediction for PHTHALIC ANHYDRIDE; not experimental data.

Simulated EI mass spectrum

On-demand educational fragmentation for PHTHALIC ANHYDRIDE; not experimental data.

Sources

Molecule identity

Retrieved 8/7/2026. Reuse status is summarized by the badge; open the source for full details.

PubChem(link only)

simulated IR

ChemForge original educational simulation.

ChemArche Original Educational Content(redistributable)
Open source record