CAS Registry Number: 74-89-5
CAS Name: Methanamine
Additional Names: monomethylamine; aminomethane
Molecular Formula: CH5N
Molecular Weight: 31.06
Percent Composition: C 38.67%, H 16.23%, N 45.10%
Line Formula: CH3NH2
Literature References: Occurs in herring brine, in urine of dogs after eating meat, in certain plants such as Mentha aquatica, in crude methanol together with di- and trimethylamine. Made by heating methyl alcohol, ammonium chloride, and zinc chloride to ~300°; by heating ammonium chloride and formaldehyde: Marvel, Jenkins, Org. Synth. 3, 67 (1923); from methanol + ammonia: Smith, US 2456599 (1948 to Comm. Solvents). Inhalation toxicity studies: L. A. Kinney et al., Inhalation Toxicol. 2, 29 (1990); S. N. Sarkar, M. S. Sastry, J. Environ. Biol. 13, 273 (1992).
Properties: Flammable gas at ordinary temp and pressure. Fuming liq when cooled in ice and salt mixture. d4-10.8 0.699. mp -93.5°. bp760 -6.3°; bp400 -19.7°; bp200 -32.4°; bp100 -43.7°; bp10 -73.8°. Flash pt 32.5°F (0°C). Stronger base than ammonia: pKb (25°): 3.35. Absorption spectrum: Bielecki, Henri, Compt. Rend. 156, 1861 (1913). One vol of water at 12.5° dissolves 1154 vols of the gas, and 959 vols at 25°. 100 ml of a benzene soln satd at 25° contain 10.5 g methylamine. Sol in alc; miscible with ether. LD50 orally in rats: 100-200 mg/kg (Kinney). LC50 in rats: 0.448 ml/l (Sarkar, Sastry).
Melting point: mp -93.5°
Boiling point: bp760 -6.3°; bp400 -19.7°; bp200 -32.4°; bp100 -43.7°; bp10 -73.8°
Flash point: Flash pt 32.5°F (0°C)
pKa: pKb (25°): 3.35
Density: d4-10.8 0.699
Toxicity data: LD50 orally in rats: 100-200 mg/kg (Kinney); LC50 in rats: 0.448 ml/l (Sarkar, Sastry)
Derivative Type: Hydrochloride
Properties: Deliquescent tetragonal tablets from alcohol, mp 227-228° with sublimation. bp15 225-230°. Sol in water, in abs alcohol. 100 g of boiling abs alcohol dissolve 23.01 g. Insol in chloroform, acetone, ether, ethyl acetate. Keep well closed. LD50 orally in rats: 1600-3200 mg/kg (Kinney).
Melting point: mp 227-228° with sublimation
Boiling point: bp15 225-230°
Toxicity data: LD50 orally in rats: 1600-3200 mg/kg (Kinney)
CAUTION: Potential symptoms of overexposure are irritation of eyes, skin and respiratory system; coughing; skin and mucous membrane burns; dermatitis; conjunctivitis; direct contact with liquid may cause frostbite. See NIOSH Pocket Guide to Chemical Hazards (DHHS/NIOSH 97-140, 1997) p 200.
Use: Methylamine is used in tanning. Methylamine and methylamine hydrochloride are used in organic synthesis for introducing the methylamino group.