K

Ketene

CH₂=C=O CAS 463-51-4
Quick Reference
Formula / NotationCH₂=C=O
CAS Number463-51-4
Also Known AsKetene gas, ethenone, carbomethene, keten

What is Ketene?

Ketene is the simplest member of the ketene family — an organic compound with the formula CH₂=C=O containing a cumulated diene system (C=C=O). It is a colorless, toxic gas with a penetrating odor. Ketene is highly reactive and acts as an acetylating agent. It is prepared industrially by pyrolysis of acetic acid or acetone.

Formula & Notation

CH₂=C=O

Other Names / Synonyms: Ketene gas, ethenone, carbomethene, keten

Properties & Characteristics

Molecular formula: C₂H₂O. Molecular weight: 42.04 g/mol. Boiling point: −56°C. Melting point: −151°C. Gas at room temperature. Highly reactive — reacts with water (acetic acid), alcohols (esters), amines (amides), carboxylic acids (anhydrides). Cumulated diene structure.

Uses & Applications

Acetylation reactions in organic synthesis. Manufacturing acetic anhydride. Cellulose acetate production. Pharmaceutical synthesis. Polymer chemistry. Laboratory acetylating agent (alternative to acetic anhydride).

Safety Information

Highly toxic — TLV: 0.5 ppm. Lachrymatory and severe irritant to eyes, respiratory tract, and skin. Reactive with moisture, forming acetic acid. Highly flammable. Handle in fume hood with appropriate respiratory protection. IDLH: 1.5 ppm.

Always consult the SDS/MSDS before handling any chemical. This information is for educational purposes only.

Key Facts

Term Ketene
Formula CH₂=C=O
CAS Number 463-51-4
Synonyms Ketene gas, ethenone, carbomethene, keten

Frequently Asked Questions

Ketene is the simplest member of the ketene family — an organic compound with the formula CH₂=C=O containing a cumulated diene system (C=C=O). It is a colorless, toxic gas with a penetrating odor. Ketene is highly reactive and acts as an acetylating agent. It is prepared industrially by pyrolysis of acetic acid or acetone.

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