A colorless highly reactive gas with a penetrating odor. mp: -150°C, bp: -56°C. Reacts violently with water. Soluble in diethyl ether and acetone. Severely irritates the eyes, the skin and the respiratory tract. Used is the manufacture of acetic anhydride, sorbic acid, cinnamic acids, chloroacetyl chloride and other materials. Readily polymerizes and cannot be shipped or stored. Is obtained instead as needed from diketene.

DIKETENE (CAS: 674-82-8; Formula: C4H2O2 ) is a colorless liquid with a pungent odor. mp: -6.5°C; bp: 127°C. Density 1.08 g/cm3. Reacts violently with water. Is obtained from the dimerization of ketene and can be stored and transported under refrigeration. A severe lachrymator (irritates the eyes, the respiratory tract, and the skin as well). Depolymerizes at 650°C to give ketene.

• Highly Flammable
• Polymerizable
• Water-Reactive

No rapid reaction with air. Reacts violently with water to form acetic acid.

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

HIGHLY FLAMMABLE: Will be easily ignited by heat, sparks or flames. CAUTION: Methanol (UN1230) will burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.) Vapors may form explosive mixtures with air. Vapors may travel to source of ignition and flash back. Most vapors are heavier than air. They will spread along the ground and collect in low or confined areas (sewers, basements, tanks, etc.). Vapor explosion and poison hazard indoors, outdoors or in sewers. Those substances designated with a (P) may polymerize explosively when heated or involved in a fire. Runoff to sewer may create fire or explosion hazard. Containers may explode when heated. Many liquids will float on water. (ERG, 2020)

Excerpt from NIOSH Pocket Guide for Ketene:

Exposure Routes: Inhalation, skin and/or eye contact

Symptoms: Irritation eyes, skin, nose, throat, respiratory system; pulmonary edema

Target Organs: Eyes, skin, respiratory system (NIOSH, 2023)

KETENE is extremely flammable. Mixtures with air are explosive. Reacts violently with water; reacts vigorously with alcohols, ammonia. Readily polymerizes and cannot be shipped or stored. Is obtained instead as needed from diketene.

DIKETENE is extremely flammable. Forms explosive vapor/air mixtures above 33°C. Undergoes a further exothermic polymerization that is retarded by storage in the solid state (below -6.5°C) or by the use of stabilizing additives. This polymerization becomes violent (with risk of fire or explosion) with warming or on contact with acids or bases. Reacts violently with water.

• Ketones
• Hydrocarbons, Aliphatic Unsaturated
• Polymerizable Compounds

Use caution: Liquids with this reactive group classification have been known to react with the absorbents listed below. More info about absorbents, including situations to watch out for...

• Mineral-Based & Clay-Based Absorbents
• Dirt/Earth

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

IMMEDIATE PRECAUTIONARY MEASURE: Isolate spill or leak area for at least 50 meters (150 feet) in all directions.

SPILL: See ERG Table 1 - Initial Isolation and Protective Action Distances on the UN/NA 2521 datasheet.

FIRE: If tank, rail car or tank truck is involved in a fire, ISOLATE for 800 meters (1/2 mile) in all directions; also, consider initial evacuation for 800 meters (1/2 mile) in all directions. (ERG, 2020)

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

CAUTION: The majority of these products have a very low flash point. Use of water spray when fighting fire may be inefficient. CAUTION: Methanol (UN1230) will burn with an invisible flame. Use an alternate method of detection (thermal camera, broom handle, etc.).

SMALL FIRE: Dry chemical, CO2, water spray or alcohol-resistant foam.

LARGE FIRE: Water spray, fog or alcohol-resistant foam. If it can be done safely, move undamaged containers away from the area around the fire. Dike runoff from fire control for later disposal. Avoid aiming straight or solid streams directly onto the product.

FIRE INVOLVING TANKS OR CAR/TRAILER LOADS: Fight fire from maximum distance or use unmanned master stream devices or monitor nozzles. Cool containers with flooding quantities of water until well after fire is out. Withdraw immediately in case of rising sound from venting safety devices or discoloration of tank. ALWAYS stay away from tanks engulfed in fire. For massive fire, use unmanned master stream devices or monitor nozzles; if this is impossible, withdraw from area and let fire burn. (ERG, 2020)

Excerpt from ERG Guide 131 [Flammable Liquids - Toxic; polymerization hazard]:

ELIMINATE all ignition sources (no smoking, flares, sparks or flames) from immediate area. All equipment used when handling the product must be grounded. Do not touch or walk through spilled material. Stop leak if you can do it without risk. Prevent entry into waterways, sewers, basements or confined areas. A vapor-suppressing foam may be used to reduce vapors.

SMALL SPILL: Absorb with earth, sand or other non-combustible material and transfer to containers for later disposal. Use clean, non-sparking tools to collect absorbed material.

LARGE SPILL: Dike far ahead of liquid spill for later disposal. Water spray may reduce vapor, but may not prevent ignition in closed spaces. (ERG, 2020)

Excerpt from NIOSH Pocket Guide for Ketene:

Skin: No recommendation is made specifying the need for personal protective equipment for the body.

Eyes: No recommendation is made specifying the need for eye protection.

Wash skin: No recommendation is made specifying the need for washing the substance from the skin (either immediately or at the end of the work shift).

Remove: No recommendation is made specifying the need for removing clothing that becomes wet or contaminated.

Change: No recommendation is made specifying the need for the worker to change clothing after the workshift. (NIOSH, 2023)

No information available.

Excerpt from NIOSH Pocket Guide for Ketene:

Breathing: RESPIRATORY SUPPORT - If a person breathes large amounts of this chemical, move the exposed person to fresh air at once. If breathing has stopped, perform artificial respiration. Keep the affected person warm and at rest. Get medical attention as soon as possible. (NIOSH, 2023)

• CARBOMETHENE
• ETHENONE
• KETENE
• KETENE (C2H2O)
• KETENE; (CARBOMETHENE, ETHENONE)
• KETO-ETHYLENE
• KETOETHYLENE