Chemical Properties
Methylamine is a colorless, fi sh-like smelling gas at room temperature. It is used in a variety of industries, such as the manufacture of dyestuffs, treatment of cellulose, acetate rayon, as a fuel additive, rocket propellant, and in leather tanning processes.
General Description
A colorless gas or a liquid. Pungent fishy odor resembling odor of ammonia. The liquid boils at 20.3°F hence vaporizes rapidly when unconfined. Vapors are heavier than air and may collect in low-lying areas. Easily ignited under most conditions. Under prolonged exposure to intense heat the containers may rupture violently and rocket. Used for making pharmaceuticals, insecticides, paint removers, surfactants, rubber chemicals.
Reactivity Profile
METHYLAMINE neutralizes acids in exothermic reactions to form salts plus water. May be incompatible with isocyanates, halogenated organics, peroxides, phenols (acidic), epoxides, anhydrides, and acid halides. Flammable gaseous hydrogen is generated in combination with strong reducing agents, such as hydrides.
Air & Water Reactions
Highly flammable. Very soluble in water; the solutions are strongly basic and therefore corrosive. Liquid fumes in air.
Hazard
(Gas and liquid) Dangerous fire risk. Explosive limits in air 5–21%. Strong irritant to tissue.
Eye, skin and upper respiratory tract irritant.
Health Hazard
Exposures to methylamine are known to cause adverse health effects among occupational workers. The workers demonstrate symptoms of toxicity that include, but are not limited to, irritation to the eyes, nose, and throat. Studies have indicated that the compound causes injury to the eyes through corneal opacities and edema hemorrhages in the conjunctiva, and injury to the liver. Studies of Guest and Varma indicated no signifi cant deleterious effects on the internal organs or skeletal deformities in experimental mice
Health Hazard
Exposures to methylamine are known to cause adverse health effects among occupational workers. The workers demonstrate symptoms of toxicity that include, but are not limited to, irritation to the eyes, nose, and throat. Studies have indicated that the compound causes injury to the eyes through corneal opacities and edema hemorrhages in the conjunctiva, and injury to the liver. Studies of Guest and Varma indicated no signifi cant deleterious effects on the internal organs or skeletal deformities in experimental mice.
Health Hazard
VAPOR: Irritating to eyes, nose and throat. If inhaled will cause coughing or difficult breathing. LIQUID: Will burn skin and eyes.
Potential Exposure
Methylamine is used in organic
synthesis; a starting material for N-oleyltaurine, a surfactant; and p-N-methylaminophenol sulfate, a photographic
developer. It has possible uses in solvent extraction systems
in separation of aromatics from aliphatic hydrocarbons.
It is also used in the synthesis of many different pharmaceuticals; pesticides and rubber chemicals.
Fire Hazard
FLAMMABLE. POISONOUS GASES MAY BE PRODUCED IN FIRE. Containers may explode in fire. Flashback along vapor trail may occur. Vapor may explode if ignited in an enclosed area. Toxic nitrogen oxides may be formed. Vapors are heavier than air and may travel considerable distance to a source of ignition and flash back.
First aid
If this chemical gets into the eyes, remove any
contact lenses at once and irrigate immediately for at least
15 minutes, occasionally lifting upper and lower lids. Seek medical attention immediately. If this chemical contacts the
skin, remove contaminated clothing and wash immediately
with soap and water. Seek medical attention immediately.
If this chemical has been inhaled, remove from exposure,
begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPR if
heart action has stopped. Transfer promptly to a medical
facility. When this chemical has been swallowed, get medical attention. Give large quantities of water and induce
vomiting. Do not make an unconscious person vomit.
Medical observation is recommended for 24 to 48 hours
after breathing overexposure, as pulmonary edema may be
delayed. As first aid for pulmonary edema, a doctor or
authorized paramedic may consider administering a drug or
other inhalation therapy.
Shipping
UN1061 Methylamine, anhydrous, Hazard Class:
2.1; Labels: 2.1-Flammable gas. UN1235 Methylamine,
aqueous solution, Hazard Class: 3; Labels: 3-Flammable
liquid, 8-Corrosive material. Cylinders must be transported
in a secure upright position, in a well-ventilated truck.
Protect cylinder and labels from physical damage. The
owner of the compressed gas cylinder is the only entity
allowed by federal law (49CFR) to transport and refill
them. It is a violation of transportation regulations to refill
compressed gas cylinders without the express written permission of the owner.
Incompatibilities
A medium-strong base. Reacts violently
with strong acids; mercury, strong oxidizers; nitromethane.
Corrosive to copper, zinc alloys; aluminum, and galvanized
surfaces.
Description
Methylamine is a colorless gas with a fish- or ammonia-like odor; at low concentrations a fishy odor. Shipped as a liquefied compressed gas. The odor threshold is 3.2 ppm. Molecular weight= 31.07; Specific gravity (H2O:1)= 0.7 (liquid);Boiling point=6℃; Freezing/ Melting point=94℃; Relative vapor density (air= 1)= 1.08; Vapor pressure= 3 atm; Flash point=flammable gas; Autoignition temperature=430℃. Explosive limits: LEL= 4.9%; UEL= 20.7%. Hazard Identification (based on NFPA-704 M Rating System): Health 3, Flammability 4, Reactivity 0. Soluble in water.
Waste Disposal
Return refillable compressed
gas cylinders to supplier. Controlled incineration (incinerator
equipped with a scrubber or thermal unit to reduce nitrogen
oxides emissions).
Physical properties
Colorless, flammable gas with a strong ammonia-like odor. An experimentally determined
recognition odor threshold concentration of 21 ppbv was reported by Leonardos et al. (1969). Odor
threshold concentrations of 4.7 ppmv and 35 ppbv were experimentally determined by Nishida et
al. (1979) and Nagata and Takeuchi (1990), respectively.
Definition
A colorless flammable gas that
smells like ammonia. It is the simplest primary
amine, used for making herbicides
and other organic chemicals.
Definition
ChEBI: The simplest of the methylamines, consisting of ammonia bearing a single methyl substituent.
Definition
methylamine: A colourless flammablegas, CH3NH2; m.p. –93.5°C; b.p.–6.3°C. It can be made by a catalyticreaction between methanol and ammoniaand is used in the manufactureof other organic chemicals.
Production Methods
Several methods are currently used for synthesis of methylamine. Virtually all
produce a mixture of primary, secondary, and tertiary amines which can be
continuously separated by distillation and extraction. The most commonly used
synthesis involves heating ammonium chloride and methyl alcohol (ratio varies
from 2:1 to 6:1, depending on desired ratio of amines) to about 300°C in the
presence of a catalyst such as zinc chloride. Alternatively, methylamine can be
synthesized by heating ammonium chloride and formaldehyde in the presence of
H2 and a hydrogenation catalyst such as nickel or platinum. Methylamine is
generally marketed as a liquid or a 33% aqueous solution (HSDB 1988).
Industrial uses
Methylamine and its hydrochloride salt are widely used in organic synthesis for
introducing the methylamino group. In 1976, industrial consumption was 32,000
tons/year. One of its most important uses is in the preparation of amide-type
surfactants. It is also used in the preparation of drugs such as adrenaline and
synthetic caffeine. It serves as the base for more than twenty commercial products,
among those included are photographic developers, insecticides, and antihistamine
drugs (Beard and Noe 1981). It is also widely used in tanning and has been
used in the separation of aromatics from aliphatic hydrocarbons (Sittig 1981).
Carcinogenicity
Methylamine was positive in the
mouse lymphoma assay and negative in the Ames assay.
Source
Methylamine was detected in cauliflower (65 ppm), carrots (3,970 ppm), tea leaves (50
ppm), red and white cabbage (3.4 to 22.7 ppm), corn (27 ppm), kale leaves (16.6 ppm), barley
seeds (4.5 ppm), epidermis of apples (4.5 ppm), celery (6.4 ppm), sweetflag, celandine, and
tobacco leaves (Duke, 1992).
Environmental Fate
Photolytic. The rate constant for the reaction of methylamine and OH radicals in the atmosphere
at 300 K is 1.3 x 10-13 cm3/molecule?sec (Hendry and Kenley, 1979).
Low et al. (1991) reported that the photooxidation of aqueous primary amine solutions by UV
light in the presence of titanium dioxide resulted in the formation of ammonium and nitrate ions.
Chemical/Physical. In an aqueous solution, chloramine reacted with methylamine to form Nchloromethylamine
(Isaac and Morris, 1983).
Reacts with acids forming water-soluble salts.
Metabolism
Methylamine is a normal body constituent in several species and is known to be
generated endogenously from epinephrine (Schayer et al 1952) and creatine
(Davis and DeRopp 1961). It has also recently been detected in the urine of male
CBA/cA mice treated with N-methylformamide (Kestell et al 1985). Mammalian
metabolism of methylamine is rapid yet the enzymes involved are not yet known.
Simehnhoff (1975) suggested that methylamine is methylated to dimethylamine as
it appeared not to be oxidized by amine oxidases yet was rapidly absorbed and not
excreted in the urine. Dar et al (1985) conducted studies using methyl-[14C]-
labeled methylamine injected i.p. into rats to assess the role of monoamine oxidase
in the metabolism of methylamine in the rats. Methylamine underwent rapid
oxidation as more than 30% of the 14C was recovered as 14CO2 in the first 2-6 h
following exposure and 52% was expired in the first 24 h. Pretreatment of the rats
with long acting monoamine oxidase inhibitors significantly inhibited methylamine
metabolism, however short term inhibitors were without effect. Combinations
of the drugs suggested that monoamine oxidase was not responsible for
metabolism of methylamine and that a closely related enzyme such as methylamine
oxidase, previously proposed by Werner and Seiber (1963), may be
involved.
It has also been reported that intestinal microflora may degrade methylamine
(Iyer and Kailio 1958). Dar et al (1985) found that pretreatment of rats with
neomycin to reduce bacterial microorganisms resulted in only a slight inhibition of
14C expiration during the initial 6 h following methylamine administration. These
results indicate that, at least in the rat, bacterial oxidation of methylamine in the
intestine is negligible.
storage
Methylamine is stored in a cool, well-ventilated noncombustible area separatedfrom possible sources of ignition andoxidizing substances and mercury. Itssolutions are stored in a flammable liquidstorage room or cabinet. The gas is shippedin steel cylinders or tank cars; the liquid isshipped in steel drums or tank cars.
Purification Methods
Dry the amine with sodium or BaO. It is commercially available in metal cylinders. [Beilstein 4 IV 118.]
Toxicity evaluation
The corrosive nature of methylamine produces irritation effects at
all points of contact which is largely responsible for its toxic actions.
Using radiotracer techniques, labeled macromolecules were fragmented
and the formaldehyde generated interacts with proteins in
vivo suggesting a risk factor for initiation of endothelial injury and
subsequent atherosclerosis. Increased semicarbazide-sensitive
amine oxidase catalyzes the conversion of methylamine to formaldehyde
and increased activity has been found in patients with
diabetes mellitus, chronic heart failure, and cerebral infarct and is
associated with obesity. The deamination of methylamine may
contribute to protein deposition, the formation of plaques, and
inflammation and be may be involved in the pathophysiology of
chronic vascular and neurologic disorders such as diabetes,
atherosclerosis, and Alzheimer’s disease.
