Chemical Properties
colorless, highly refractive liquid or colorless gas, which burns with a blue sooty flame; odor like acrolein or mustard oil; structure: O=C=C=C=O [MER06]
Uses
preparation of malonates; improving dye affinity of fibers.
Physical properties
Colorless gas; strong, pungent odor; gas density 2.985 g/L; liquid density 1.114 g/mL at 0°C; refractive index 1.4538 (at 0°C); vapor pressure 588 torr at 0°C; liquefies at 6.8°C; freezes at -111.3°C; burns with a blue sooty flame; reacts with water. The compound is unstable, polymerizing on storage.
Definition
ChEBI: Carbon suboxide is a carbon oxide and a member of allenes.
Preparation
Carbon suboxide is prepared by dehydration of malonic acid with phosphorus pentoxide in vacuum at 140 to 150°C:
CH2(COOH)2→ C3O2 + 2H2O
Alternatively, the compound may be prepared by thermal dissociation of diacetyltartaric anhydride.
Hazard
Carbon suboxide forms explosive mixtures in air. The lower and upper explosive limits are 6 to 30% by volume in air, respectively. The gas is a strong lacrimator and an irritant to eyes, nose and respiratory tract. Exposure to high concentations is dangerous. .
