ketene Chemical Properties
- Melting point:
- Boiling point:
- bp -56°
- refractive index
- 1.3040 (estimate)
- Exposure limits
- TLV-TWA 0.9 mg/m3 (0.5 ppm); STEL 3.0 mg/m3 (1.5 ppm) (ACGIH); IDLH 50 ppm (NIOSH).
- EPA Substance Registry System
- Ketene (463-51-4)
ketene Usage And Synthesis
Colorless gas with a sharp penetrating odor;liquefies at -56°C (-68.8°F); solidifies at-151°C (-239.8°F); soluble in alcohol andacetone, decomposed by water.
For the conversion of higher acids into their anhydrides; for acetylation in the manufacture of cellulose acetate and aspirin.
Ketene is used as an acetylating agent inthe production of cellulose acetate, aspirin,acetic anhydride, and in various organicsyntheses.
Ketene is a highly toxic gas. It causes severeirritation to the eyes, nose, throat, and skin.Exposure to 10–15 ppm for several minutescan injure the respiratory tract. It causespulmonary edema. A 30-minute exposure to23 ppm was lethal to mice and a 10-minuteexposure to 200 and 750 ppm caused deathto monkeys and cats.
Ketene in its gaseous state should be flammable and explosive in air. The pure compound, however, polymerizes readily and cannot be stored as a gas. Its flash point and LEL and UEL values are not reported. It can react violently with oxidizers and many organic compounds. Its small size and the olefinic unsaturation impart further reactivity to the molecule.
Ketene is prepared by pyrolysis of acetic anhydride. Purify it by passing through a trap at -75o and collecting in a liquid-nitrogen-cooled trap. Ethylene is removed by evacuating the ethylene in an isopentane-liquid-nitrogen slush pack at -160o. Store it at room temperature in a suitable container in the dark or better at -80o, but do not store it under pressure as it may EXPLODE. It is a strong IRRITANT when inhaled and is as poisonous as phosgene. See diketene in “Heterocyclic Compounds”, Chapter 4. [Hurd Org Synth Coll Vol I 330 1941, Andreades & Carlson Org Synth Coll Vol V 679 1973.]
ketene Preparation Products And Raw materials
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