Title: Hydrogen Chloride
CAS Registry Number: 7647-01-0
CAS Name: Anhydrous hydrochloric acid
Molecular Formula: ClH
Molecular Weight: 36.46
Percent Composition: Cl 97.24%, H 2.76%
Line Formula: HCl
Literature References: See also Hydrochloric Acid. Produced industrially by the interaction of NaCl and H2SO4; from NaCl, SO2, air and water vapor; by controlled combination of the elements; or as a by-product of the synthesis of chlorinated hydrocarbons: A. C. Cumming, Hydrochloric Acid and Salt Cake (Gurney and Jackson, London, 1923); N. A. Laury, Hydrochloric Acid and Sodium Sulfate (Chem. Catalog Co., New York, 1927); Maude, Chem. Eng. Prog. 44, 179 (1948); Faith, Keyes & Clark's Industrial Chemicals, F. A. Lowenheim, M. K. Moran, Eds. (Wiley-Interscience, New York, 4th ed., 1975) pp 454-461. Prepn of pure HCl for research purposes: Hönigschmid et al., Z. Anorg. Allg. Chem. 163, 315 (1927); Kemp, J. Chem. Educ. 37, 142 (1960); Schmeisser in Handbook of Preparative Inorganic Chemistry vol. 1, G. Brauer, Ed. (Academic Press, New York, 2nd ed., 1963) pp 280-282. Toxicity: K. I. Darmer et al., Am. Ind. Hyg. Assoc. J. 35, 623 (1974). Reviews of prepn and properties: Addison, Lewis in Mellor's vol. II, suppl. I (originally published as suppl. II, part I) 402-475 (1956); Downs, Adams in Comprehensive Inorganic Chemistry vol. 2, J. C. Bailar, Jr. et al., Eds. (Pergamon Press, Oxford, 1973) pp 1280-1329; D. S. Rosenberg in Kirk-Othmer Encyclopedia of Chemical Technology vol. 12 (Wiley-Interscience, New York, 3rd ed., 1980) pp 983-1015.
Properties: Colorless, corrosive, nonflammable gas. Characteristic pungent odor. Fumes in air. d 1.268 (air = 1.000). d 1.639 g/l. mp -114.22°. bp760 -85.05°; bp100 -114.61°; bp10 -137.77°; bp1.0 -154.37°. Critical temp 51.4°; critical pressure 81.6 atm; critical density 0.42 g/ml. nD20 (liquid under pressure) 1.256. Heat capacity at constant volume (15°): 0.1939 cal/g/°C. Heat capacity at constant pressure (15°): 0.1375 cal/g/°C. Heat of vaporization at -85°: 3860 cal/mole; heat of soln (infinite dilution) -17.88 kcal/mole; heat of formation of gas at 25°: -22.063 kcal/mole. Dielectric constant (gas at 0°) 1.0046; dipole moment 1.07. Soly in water (g/100 g H2O): 82.3 (0°); 67.3 (30°); 63.3 (40°); 59.6 (50°); 56.1 (60°). Forms a const boiling mixture: 20.22 g/100 g soln; see Hydrochloric Acid. Soly in methanol (g/100 g soln): 54.6 (-10°); 51.3 (0°); 47.0 (20°); 43.0 (30°); in ethanol: 45.4 (0°); 42.7 (10°); 41.0 (20°); 38.1 (30°); in ether: 37.52 (-10°); 35.6 (0°); 24.9 (20°); 19.47 (30°). LC50 (30 min) in mice, rats: 2142, 5666 ppm (Darmer).
Melting point: mp -114.22°
Boiling point: bp760 -85.05°; bp100 -114.61°; bp10 -137.77°; bp1.0 -154.37°
Index of refraction: nD20 (liquid under pressure) 1.256
Density: d 1.268 (air = 1.000); d 1.639 g/l
Toxicity data: LC50 (30 min) in mice, rats: 2142, 5666 ppm (Darmer)
CAUTION: Potential symptoms of overexposure are irritation of nose, throat and larynx; coughing, choking; dermatitis; direct contact with solutions may cause eye and skin burns; direct contact with liquid may cause frostbite. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 166. See also Patty's Industrial Hygiene and Toxicology vol. 2B, G. D. Clayton, F. E. Clayton, Eds. (Wiley-Interscience, New York, 3rd ed., 1981) pp 2959-2961.
Use: In the manuf of pharmaceutical hydrochlorides, vinyl chloride from acetylene, alkyl chlorides from olefins, and arsenious chloride from arsenious oxide. In the chlorination of rubber, as a gaseous flux for babbitting operations. In organic reactions involving isomerization, polymerization, and alkylation. For making chlorine where economical. |