6014. Methylamine

Nomenclature

CAS number: 74-89-5
Methanamine; monomethylamine; aminomethane.
CH5N; mol wt 31.06.
C 38.67%, H 16.23%, N 45.10%.
CH3NH2.

Description and 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 liquid when cooled in ice and salt mixture. d410.8 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).

Derivative

Hydrochloride.

Nomenclature

CAS number: 593-51-1
CH5N.HCl; mol wt 67.52.
C 17.79%, H 8.96%, N 20.74%, Cl 52.51%.

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).

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.