70. Acetonitrile

Nomenclature

CAS number: 75-05-8
Methyl cyanide; cyanomethane; ethanenitrile.
C2H3N; mol wt 41.05.
C 58.52%, H 7.37%, N 34.12%.
CH3CN.

Description and references

Small amounts occur in coal tar. Obtained commercially as a byproduct in manuf of acrylonitrile, q.v. Prepn by dehydration of acetamide: H. Adkins, B. H. Nissen, J. Am. Chem. Soc. 46, 130 (1924); A. I. Vogel, Practical Organic Chemistry (Longmans, London, 3rd ed., 1959) p 407; Gattermann-Wieland, Praxis des Organischen Chemikers (de Gruyter, Berlin, 40th ed., 1961) p 125; or from acetylene and ammonia: DE 365432; Chem. Zentralbl. 1924 I, 2398; 1925 II, 1563. Review of purification methods: Techniques of Chemistry vol. II, entitled “Organic Solvents”, J. A. Riddick, W. B. Bunger, Eds. (Wiley-Interscience, New York, 3rd ed., 1970) pp 798-805. Purification and use as a solvent for inorganic fluorides: J. M. Winfield, J. Fluorine Chem. 25, 91 (1984).

Properties

Liquid. Ether-like odor. Poisonous, flammable, combustible. Burns with a luminous flame. mp 45.7°. bp760 81.6°. Flash pt, open cup: 6°C (42°F). d415 0.78745; d430 0.77125. nD15 1.34604, nD30 1.33934. Dielectric constant at 25° = 37.5. Surface tension at 20° = 29.04 dynes/cm. Misc with water, methanol, methyl acetate, ethyl acetate, acetone, ether, acetamide solutions, chloroform, carbon tetrachloride, ethylene chloride and many unsaturated hydrocarbons. Immiscible with many saturated hydrocarbons (petroleum fractions). Constant boiling mixture with water contains 16% H2O and bp 76°. Log P (octanol/water): 0.34. Vapor pressure (20°): 74 mmHg. pKa: 25. LD50 orally in rats: 3800 mg/kg. See: H. F. Smyth, C. P. Carpenter, J. Ind. Hyg. Toxicol. 30, 63 (1968).

Caution

Potential symptoms of overexposure are irritation of nose, throat; asphyxia; nausea, vomiting; chest pain; weakness; stupor, convulsions. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 4.

Use

In organic synthesis as starting material for acetophenone, α-naphthaleneacetic acid, thiamine, acetamidine. To remove tars, phenols, and coloring matter from petroleum hydrocarbons. To extract fatty acids from fish liver oils and other animal and vegetable oils. Polar solvent in non-aqueous titrations; non-aqueous solvent for inorganic salts. In HPLC, UV, and electrochemistry applications. Facilitates reactions between organic substrates and inorganic materials.