Title: Carbon Suboxide
CAS Registry Number: 504-64-3
CAS Name: 1,2-Propadiene-1,3-dione
Additional Names: tricarbon dioxide
Molecular Formula: C3O2
Molecular Weight: 68.03
Percent Composition: C 52.97%, O 47.04%
Line Formula: O=C=C=C=O
Literature References: Prepn by thermal decompn of malonic acid: Glemser in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) p 648. Reactions in organic synthesis: Dashkevich, Beilin, Russ. Chem. Rev. 36, 391 (1967). Comprehensive reviews: Reyerson, Kobe, Chem. Rev. 7, 479 (1930); Vol'kenshtein, Usp. Khim. 4, 610 (1935); Grauer, Chimia 14, 11 (1960); T. Kappe, E. Ziegler, Angew. Chem. Int. Ed. 13, 491-504 (1974), reprinted in New Synthetic Methods vol. 1 (Verlag Chemie, Weinheim, 1975) pp 29-69.
Properties: Colorless, highly refractive liquid or colorless gas which burns with a blue, sooty flame. Odor like acrolein and mustard oil. mp -111.3°. bp760 6.8°. d40 1.114. n0D 1.45384; nD-12 1.46757. Vapor pressure at 0°: 587-589 mm. Explosive limits, 6 to 30 vol % in air. Dipole moment: 0.7D. Thermodynamic constants: Thompson, Trans. Faraday Soc. 37, 249 (1941). The gas can be stored at pressures of up to 100 mm, but even at these pressures polymerization may occur, giving a red, water-sol product. This invariably occurs at higher pressure or in the liquid state. Polymerization facilitated by presence of P2O5. Dec when passed through heated glass tubes, forming a mirror surface. Difficultly sol in carbon disulfide, xylene. With water forms malonic acid quantitatively. Forms malonamide with ammonia.
Melting point: mp -111.3°
Boiling point: bp760 6.8°
Index of refraction: n0D 1.45384; nD-12 1.46757
Density: d40 1.114
CAUTION: In small amounts acts as a lacrimator; in high concns attacks eyes, nose, respiratory organs, producing a feeling of suffocation.
Use: Prepn of malonates; improving dye affinity of fibers.