Title: Acetic Anhydride
CAS Registry Number: 108-24-7
Additional Names: Acetic oxide; acetyl oxide
Molecular Formula: C4H6O3
Molecular Weight: 102.09
Percent Composition: C 47.06%, H 5.92%, O 47.02%
Line Formula: (CH3CO)2O
Literature References: Equivalent to 117.64% acetic acid. Made formerly from sod. acetate and acetyl or sulfuryl chloride; now usually obtained from acetaldehyde or acetic acid: Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 16-20. Of industrial importance is also the ketene process, starting with the thermal decomposition of acetone: Schmidlin, Bergmann, Ber. 43, 2821 (1910). Toxicity study: H. F. Smyth et al., Arch. Ind. Hyg. Occup. Med. 4, 119 (1951).
Properties: Very refractive liquid; strong acetic odor. Readily combustible. Fire hazard. Flash pt 130°F. d415 1.080. mp -73°. bp 139°. nD20 1.3904. Slowly soluble in water, forming acetic acid; with alcohol forms ethyl acetate; sol in chloroform, ether. LD50 orally in rats: 1.78 g/kg (Smyth).
Melting point: mp -73°
Boiling point: bp 139°
Flash point: Flash pt 130°F
Index of refraction: nD20 1.3904
Density: d415 1.080
Toxicity data: LD50 orally in rats: 1.78 g/kg (Smyth)
CAUTION: Potential symptoms of overexposure are conjunctivitis, lacrimation, corneal edema, opacity and photophobia; nasal, pharyngeal irritation; cough, dyspnea and bronchitis; skin burns, vesiculation and sensitization dermatitis. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 2.
Use: Manuf acetyl compounds, cellulose acetates. As acetulizer and solvent in examining wool fat, glycerol, fatty and volatile oils, resins; detection of rosin. Widely used in organic syntheses, e.g., as dehydrating agent in nitrations, sulfonations and other reactions where removal of water is necessary. |