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Pulp and paper chemicals

Diketene

Also known as 4-Methylene-2-oxetanone, 2-Oxetanone, 4-methylene-, Ketene, dimer

CAS 674-82-8Formula C4H4O2Molar mass 84.07 g/molEC 211-617-1
GHS signal word: Warning. Pictograms: Flammable, Harmful or irritant 10 suppliers listed
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Diketene chemical structure, C4H4O2, CAS 674-82-8
2D chemical structure

Key facts

What buyers check first

All properties
Appearance
Colorless liquid, turns brownish-yellow upon standing at room temperature
Melting point
-6.5 °C
Boiling point
127 °C
Density
1.0877 g/cm³ at 20 °C
Flash point
34 °C
HS code
293220
Category
Pulp and paper chemicals
UN number
UN 2521
Illustrative photo, 200 litre blue HDPE drums of liquid in a warehouse
Typical packagingIllustrative packaging image, not the actual product

What is Diketene?

Plain description, key identifiers and synonyms

Diketene, stabilized appears as a colorless liquid with a disagreeable odor. Slightly less dense than water. Irritates skin and eyes. Used to make paints and pharmaceuticals.

Identifiers

Registry numbers, names and line notations, tap to copy

IUPAC name
4-methylideneoxetan-2-one
CAS number
674-82-8 CAS number cross-checked
EC number
211-617-1
Molecular formula
C4H4O2
UNII
0DZ97C3Z7D
InChIKey
WASQWSOJHCZDFK-UHFFFAOYSA-N
InChI
InChI=1S/C4H4O2/c1-3-2-4(5)6-3/h1-2H2
SMILES (canonical and isomeric)
C=C1CC(=O)O1

Synonyms

  • 4-Methylene-2-oxetanone
  • 2-Oxetanone, 4-methylene-
  • Ketene, dimer
  • 3-Buteno-beta-lactone
  • Vinylaceto-beta-lactone
  • 3-Butenoic acid, 3-hydroxy-, beta-lactone
  • Acetyl ketene
  • 4-methylideneoxetan-2-one
  • 4-methyleneoxetan-2-one
  • Ethenone, dimer
  • Ketene dimer
  • Diketen
  • But-3-en-3-olide
  • Ethenone, dimer (VAN)
  • 4-Methylene-oxetan-2-one
  • Diketene, inhibited
  • 4-Methylidene-2-oxetanone
  • 5-17-09-00115 (Beilstein Handbook Reference)
  • 3-Butenoic acid, beta-lactone
  • Diketene, contains copper sulfate as stabilizer

Physical and chemical properties

Measured values and descriptors computed from the structure

Physical and chemical properties

Measured values, check the supplier specification for your grade

Appearance
Colorless liquid, turns brownish-yellow upon standing at room temperatureexp.
Odour
Pungent odorexp.
Melting point
-6.5 °Cexp.
Boiling point
127 °Cexp.
Density
1.0877 g/cm³ at 20 °Cexp.
Flash point
34 °Cexp.
Autoignition temperature
310 °Cexp.
Solubility
Very slightly soluble in water in which it decomposes slowlyexp.
Vapour pressure
VP: 1.07 kPa at 20 °Cexp.

Values vary by grade. Ask suppliers for the COA or TDS of the batch you buy.

Computed descriptors

Calculated from the structure, useful for screening and formulation

Molecular weight
84.07 g/molcalc.
Exact mass
84.0211 Dacalc.
LogP (octanol/water)
0.45calc.
Topological polar surface area
26.3 Ųcalc.
Hydrogen bond donors
0calc.
Hydrogen bond acceptors
2calc.
Rotatable bonds
0calc.
Heavy atoms
6calc.
Rings
1calc.
Aromatic rings
0calc.
Fraction sp3 carbons
0.25calc.
Formal charge
0calc.
Stereocentres
0calc.
Lipinski rule of five
Passes (0 violations)calc.

Calculated for screening. Confirm critical figures with the supplier.

Murcko scaffold

The ring system that remains when every side chain is removed

Murcko scaffold of this chemical, C=C1CC(=O)O1

C=C1CC(=O)O1

1 ring, 6 atoms. This chemical is the scaffold itself.

30 other chemicals share this scaffold

Safety and hazards

GHS classification summary, not a safety data sheet

GHS signal word
Warning
GHS02: Flammable
Flammable
GHS07: Harmful or irritant
Harmful or irritant
332WNFPA 704 rating

Hazard statements

  • H226Flammable liquid and vapour.
  • H332Harmful if inhaled.
Precautionary statements (15)
  • P210Keep away from heat, hot surfaces, sparks, open flames and other ignition sources. No smoking.
  • P233Keep container tightly closed.
  • P240Ground and bond container and receiving equipment.
  • P241Use explosion-proof electrical, ventilating and lighting equipment.
  • P242Use non-sparking tools.
  • P243Take action to prevent static discharges.
  • P261Avoid breathing dust, fume, gas, mist, vapours or spray.
  • P271Use only outdoors or in a well-ventilated area.
  • P280Wear protective gloves, protective clothing, eye protection and face protection.
  • P303 + P361 + P353If on skin (or hair): Take off immediately all contaminated clothing. Rinse skin with water or shower.
  • P304 + P340If inhaled: Remove person to fresh air and keep comfortable for breathing.
  • P317Get medical help.
  • P370 + P378In case of fire: Use appropriate media to extinguish.
  • P403 + P235Store in a well-ventilated place. Keep cool.
  • P501Dispose of contents and container in accordance with local regulations.
UN number
UN 2521
Transport hazard class
6.1
Packing group
I

GHS classification summary, not a safety data sheet (SDS). Classifications can differ by supplier, grade and concentration. Always check the supplier's SDS.

Full safety data and first aid

Diketene suppliers

Sponsored listings first, then the documented ranking: membership, verification, replies, completeness, freshness and ratings

All 10 suppliers
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Where suppliers are based

10 suppliers in 3 countries

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Diketene price

Indicative price range per kg from live supplier offers

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Uses and applications

What the substance is used for, by industry and function

Reagent in synthetic organic chemistry.

Production of acetoarylamides, pigments and toners, pesticides, food preservatives, pharmaceutical intermediates.

Diketene is a powerful bactericidal agent and can raise the octane rating of gasoline [84], but is not used for these purposes in the Western hemisphere.

How it is made

Ketene possesses a considerable tendency to polymerize. Under controlled conditions and in the appropriate dimerization medium, ketene can be dimerized to diketene, with yields of up to 85%, based on acetic acid. The remaining 15 % is made up by higher ketene oligomers. The preferred dimerization medium is diketene itself. Crude diketene, containing 3-4% acetic anhydride, is a mobile, dark brown liquid due to 8-10% higher polymers. Diketene of > 99.5% purity can be obtained by distillation.

Read more

Ultrapure diketene (99.99%) can be obtained by crystallization.

After removal of water, acetic acid and acetic anhydride, crude ketene gas is dimerized to diketene by absorbing ketene preferably in a liquid seal pump using diketene as sealing medium. When dissolved, ketene readily dimerizes to diketene. Using controlled conditions, yields of up to 85% can be achieved based on the acetic acid feed initially used in the ketene process. The obtained crude diketene consists of a mobile, dark brown liquid, containing about 5 to 10% of triketene besides small quantities of acetic anhydride (3-4%) and higher polymers. This crude product is then fractionated over a distillation column, typically yielding diketene with more than 99.5% content. In some cases, the crude diketene can be used directly in subsequent processes. If ultra-pure diketene with a content of 99.99% is required, the distilled diketene can be crystallized from ethyl acetate or ethyl acetate and cyclohexane

Regulatory status

Inventories, regulations and trade controls that list this substance

Europe

  • EU harmonised classification (CLP Annex VI)
    Index no: 606-017-00-5

United States

  • TSCA inventory (USA)
    Status: Active in US commerce

HS code and trade data

Customs classification and reported world trade statistics

Global trade

World import and export statistics for the HS code Diketene is traded under.

HS 2932.20Indicative HS code

Lactones

World exports in 2024
$1.97B
−4.7% vs 2023, imports $2.07B
2019 to 2024
Top exporters
  1. China56.3%
  2. India * partner reported7.4%
  3. Germany7.3%
Top importers
  1. United States14.2%
  2. India * partner reported13.5%
  3. Brazil8.5%

* Partner reported figures, a lower bound.

Reported customs values in USD, not prices.Full trade data

The HS code shown for Diketene is indicative (it was assigned by structure rules). Confirm the classification with your customs broker before shipping.

Frequently asked questions

Quick answers about Diketene, based on the data on this page

What is Diketene?

Diketene, stabilized appears as a colorless liquid with a disagreeable odor. Slightly less dense than water. Irritates skin and eyes. Used to make paints and pharmaceuticals.

What is the CAS number of Diketene?

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

What is the molecular formula and weight of Diketene?

The molecular formula of Diketene is C4H4O2 and its molar mass is 84.07 g/mol.

What is Diketene used for?

Reagent in synthetic organic chemistry. Production of acetoarylamides, pigments and toners, pesticides, food preservatives, pharmaceutical intermediates. Diketene is a powerful bactericidal agent and can raise the octane rating of gasoline [84], but is not used for these purposes in the Western hemisphere.

Is Diketene hazardous?

Diketene carries the GHS signal word "Warning". Main hazards: flammable liquid and vapour, harmful if inhaled. This summary is not an SDS, always read the supplier safety data sheet.

What is the HS code of Diketene?

Diketene is usually classified under HS code 293220 (Lactones). This is indicative, confirm it with your customs broker before shipping.

Where can I buy Diketene?

CompoundList lists 10 suppliers of Diketene in China, United States and Ukraine. Send one free request to get and compare quotes. Your contact details stay private until you accept a quote.

What is the price of Diketene?

Suppliers quote Diketene on request because prices depend on grade, purity, quantity and destination. A free request on CompoundList gets you several quotes to compare.

Guides for buyers

Practical guides that help when you source, ship or handle Diketene

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Data last updated 7 Oct 2026. Details may have changed, please confirm them with the supplier. Report an error on this page
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