Phthalic anhydride
The cyclic dicarboxylic anhydride that is the anhydride of phthalic acid. — ChEBI
Safety documents & references
2 indexed referencesFind a product-specific SDS
Safety guides and government classification records are not a manufacturer’s SDS. Match supplier, product number, concentration, physical form, region and revision before using a document.
Identity & molecular properties
Source-linked values| CAS number | 85-44-9 | ChEBI ↗ |
| Molecular formula | C8H4O3 | ChEBI ↗ |
| Molar mass | 148.117 g/mol | ChEBI ↗ |
| Monoisotopic mass | 148.01604 Da | ChEBI ↗ |
| Formal charge | 0 | ChEBI ↗ |
| ChEBI identifier | CHEBI:36605 | ChEBI ↗ |
Cross-source molecular data
PubChem| Molar mass | 148.11 g/mol | PubChem ↗ |
| Exact mass | 148.016043985 Da | PubChem ↗ |
| Computed XLogP | 1.3 | PubChem ↗ |
| Topological polar surface area (Ų) | 43.4 | PubChem ↗ |
| H-bond donors | 0 | PubChem ↗ |
| H-bond acceptors | 3 | PubChem ↗ |
| Rotatable bonds | 0 | PubChem ↗ |
PubChem computed values are shown separately from the ChEBI record. An exact InChIKey match was used to connect the records. Molecular descriptors do not describe a supplied product’s purity, particle size or performance.
Names & structural identifiers
Copy any identifierphthalic anhydride2-benzofuran-1,3-dioneLGRFSURHDFAFJT-UHFFFAOYSA-NO=C1OC(=O)c2ccccc21InChI=1S/C8H4O3/c9-7-5-3-1-2-4-6(5)8(10)11-7/h1-4HNames & synonyms
Names are supplied by ChEBI. Trade names and related synonyms may describe a broader product context.
Classification & relationships
ChEBI ontologyRoles recorded in ChEBI
Database role annotations describe reported biological or chemical roles; they are not product approvals or recommendations for use.
Safety classification · Japan
NITE / Japanese governmentPhthalic anhydride · H26-B-131 / -
| Endpoint | Reported classification |
|---|---|
| Acute toxicity （Oral） | Category 4 |
| Serious eye damage/eye irritation | Category 2A |
| Respiratory sensitization | Category 1A |
| Skin sensitization | Category 1 |
| Specific target organ toxicity - Single exposure | Category 3 （Respiratory tract irritation, Narcotic effects） |
| Specific target organ toxicity - Repeated exposure | Category 1 (respiratory system) |
Selected source-reported endpoints. Other endpoints, rationales and conditions remain in the original classification. Missing or unlisted information does not mean non-hazardous. This is not a global classification or transport decision.
Read the original NITE classificationMass ↔ amount of substance
Calculated from sourced massUses 148.117 g/mol from ChEBI. Assumes the substance described by this record; no purity or concentration correction is applied.
Elemental composition
Theoretical mass fractionsCOHCalculated theoretical mass fractions from the reported formula and PubChem periodic-table atomic masses. These are not assay or purity results.
Research & patent references
Selected source associationsSources & record history
Checked 27 Sep 2026Release 255, 9 September 2026. ChEBI three-star (manually annotated) source entry. View original record ↗ · CC BY 4.0
PubCAS formats source data, connects references and computes explicitly labelled conversions. CAS cross-references are supplied by ChEBI; they do not constitute CAS verification or endorsement.