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Phthalic anhydride

Also known as: 1,3-DIHYDRO-IMIDAZOL-2-ONE, 1,3-dihydro-2H-imidazol-2-one, 1,3-dihydro-2h-imidazol-2-on, 1,3-dihydroimidazolone, 1,3-dihydroisobenzofuran-1,3-dione, 1,3-isobenzofurandione, 1H-imidazol-2(3H)-one, 2(3H)-Oxo-1H-imidazole, 2,3-DIHYDRO-IMIDAZOL-2-ONE, 2,3-Dihydroimidazole-2-one, 2,3-dihydro-1H-imidazol-2-one, 2-hydroxyimidazole, 4-imidazolin-2-one, EINECS 201-607-5, MFCD00005918, isobenzofuran-1,3-dione, o-Phthalic acid anhydride, phthalic anhydride, phthallic anhydride, sd8591

Phthalic anhydride (CAS 85-44-9) is a compound in the Aromatic Hydrocarbons category listed in the Jingsj chemical database. It has the molecular formula C8H4O3 and a molecular weight of 148.116 g/mol. Key properties include a melting point of 129-132 ºC, a boiling point of 284 ºC, a density of 1.4±0.1 g/cm3 and a flash point of 152 ºC. It is classified under GHS with signal word Danger and hazard statements H302 — Harmful if swallowed, H315 — Causes skin irritation and H317 — May cause an allergic skin reaction. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.
85-44-9
Jingsj CID
J-28541-0
Molecular Formula
C8H4O3
Molecular Weight
148.116 g/mol
Category
Aromatic Hydrocarbons
Last updated
8/21/2026

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Physicochemical Properties

Melting Point129-132 ºC
Boiling Point284 ºC
Density1.4±0.1 g/cm3
Flash Point152 ºC
Exact Mass148.016037
PSA43.37000
LogP1.60
Additional Property5.1 (vs air)
Vapor Pressure0.0±0.6 mmHg at 25°C
Refractive Index1.613
Additional Property6 g/L (20 ºC)

GHS Safety & Compliance

Corrosion / Irritant / Health HazardSignal word: Danger
  • H302 — Harmful if swallowed
  • H315 — Causes skin irritation
  • H317 — May cause an allergic skin reaction
  • H318 — Causes serious eye damage
  • H334 — May cause allergy or asthma symptoms if inhaled
  • H335 — May cause respiratory irritation

Customs & Trade Information

HS Code2917350000
SummaryHS:2917350000 isobenzofuran-1,3-dione VAT:17.0% Tax rebate rate:9.0% Supervision conditions:AB MFN tariff:6.5% General tariff:30.0%

Frequently Asked Questions

What is the CAS number of Phthalic anhydride?

The CAS number of Phthalic anhydride is 85-44-9.

What are the molecular formula and molecular weight of Phthalic anhydride?

Phthalic anhydride has molecular formula C8H4O3 and molecular weight 148.116 g/mol.

Is Phthalic anhydride hazardous?

Phthalic anhydride has GHS signal word Danger and hazard statements H302 — Harmful if swallowed; H315 — Causes skin irritation; H317 — May cause an allergic skin reaction.

What are the upstream and downstream products of Phthalic anhydride?

For Phthalic anhydride, Upstream Products: o-xylene, Phthalan, Phthalic acid; Downstream Products: 2-Ethylanthraquinone.

Data compiled from public chemical databases such as PubChem and supplier catalogs; supplier offers are provided by suppliers.

Last updated:

How to cite: Jingsj. "Phthalic anhydride (CAS 85-44-9)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-28541-0 (accessed 2026-11-06).

Data for reference only; verify product details with suppliers before purchase.