Diketene

Also known as: Acetyl ketene, Acetylketene, Ketene dimer, 4-Methylene-2-oxetanone, 3-Hydroxy-3-butenoic acid beta-lactone, Ethenone dimer, Diketen, 4-Methylideneoxetan-2-one, But-1-ene-1,3-dione, DK

Diketene (CAS 674-82-8) is a compound in the Ketones category listed in the Jingsj chemical database. It has the molecular formula C4H4O2 and a molecular weight of 84.073 g/mol. Key properties include a melting point of -7.5°C, a boiling point of 127.4±0.0 °C at 760 mmHg, a density of 1.1±0.1 g/cm3 and a flash point of 34.4±0.0 °C. It is classified under GHS with signal word Danger and hazard statements H226 — Flammable liquid and vapour, H302 — Harmful if swallowed and H331 — Toxic if inhaled. No supplier offers are currently listed; request a quote. Record last updated Aug 21, 2026.

CAS No.: 674-82-8
Jingsj CID: J-29849-2
Molecular Formula: C₄H₄O₂
Molecular Weight: 84.073 g/mol
Category: Ketones
Last updated: 8/21/2026

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Physicochemical Properties

Melting Point	-7.5°C
Boiling Point	127.4±0.0 °C at 760 mmHg
Density	1.1±0.1 g/cm3
Flash Point	34.4±0.0 °C
Exact Mass	84.021126
PSA	26.30000
LogP	0.27
Additional Property	2.9 (vs air)
Vapor Pressure	11.1±0.2 mmHg at 25°C
Refractive Index	1.450

GHS Safety & Compliance

Flammable / Acute ToxicitySignal word: Danger

H226 — Flammable liquid and vapour
H302 — Harmful if swallowed
H331 — Toxic if inhaled

Frequently Asked Questions

What is the CAS number of Diketene?

The CAS number of Diketene is 674-82-8.

What are the molecular formula and molecular weight of Diketene?

Diketene has molecular formula C4H4O2 and molecular weight 84.073 g/mol.

Is Diketene hazardous?

Diketene has GHS signal word Danger and hazard statements H226 — Flammable liquid and vapour; H302 — Harmful if swallowed; H331 — Toxic if inhaled.

What are the upstream and downstream products of Diketene?

For Diketene, Upstream Products: ketene, 1-(9H-Carbazol-9-yl)ethanone, Dichloromethane; Downstream Products: 3-Oxo-N-(3-phenylpropyl)butanamide, 4'-Methoxyacetoacetanilide, N-(5-Chloro-2-methoxyphenyl)-3-oxobutanamide.

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

Last updated: 8/21/2026

How to cite: Jingsj. "Diketene (CAS 674-82-8)". Jingsj Chemical Database. https://www.jingsj.com/compound/J-29849-2 (accessed 2026-11-06).

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