Methylamine

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.

Chemical properties

colourless gas (or solution in water or methanol)

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.

Chemical properties

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.

Chemical properties

Methylamine is a derivative of ammonia in which a methyl group is substituted for a hydrogen (Schweizer et al 1978). Its reactivity is governed primarily by the unshared pair of electrons on the nitrogen, therefore methylamine is a strongly alkaline base whose most characteristic reaction is the formation of salts with acids. It will react with acid halides and acid anhydrides to form N-substituted amines. Methylamine reacts with nitrous acid to form methanol with liberation of nitrogen. It is capable of reacting with aldehydes to form aldimines or Schiffs bases (Astle 1961).

Physical properties

Colorless, flammable gas with a strong ammonia-like odor. An experimentally determined recognition odor threshold concentration of 21 ppb_v was reported by Leonardos et al. (1969). Odor threshold concentrations of 4.7 ppm_v and 35 ppb_v were experimentally determined by Nishida et al. (1979) and Nagata and Takeuchi (1990), respectively.

The Uses of Methylamine

Methylamine is used in dyeing and tanning;in photographic developer, as a fuel additive,and as a rocket propellant. It is also usedin organic synthesis and as a polymerizationinhibitor. It occurs in certain plants, such asMentha aquatica.

The Uses of Methylamine

Intermediate for accelerators, dyes, pharmaceuticals, insecticides, fungicides, surface active agents, tanning, dyeing of acetate textiles, fuel additive, polymerization inhibitor, component of paint removers, solvent, photographic developer, rocket propellent.

The Uses of Methylamine

Tanning and dyeing industries; fuel additive; chemical intermediate in the production of pharmaceuticals, insecticides, and surfactants

Definition

ChEBI: The simplest of the methylamines, consisting of ammonia bearing a single methyl substituent.

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).

Definition

A colorless flammable gas that smells like ammonia. It is the simplest primary amine, used for making herbicides and other organic chemicals.

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.

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.

Air & Water Reactions

Highly flammable. Very soluble in water; the solutions are strongly basic and therefore corrosive. Liquid fumes in air.

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.

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

VAPOR: Irritating to eyes, nose and throat. If inhaled will cause coughing or difficult breathing. LIQUID: Will burn skin and eyes.

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

Most of the studies on the toxicity of methylamine suggest it acts locally as an irritant and a sensitizer. Vapors result in eye irritation with tearing and inflammation with repeated exposure capable of inducing corneal damage. Exposure by inhalation irritates the mucous membranes of the nose, throat and lung, leading to coughing and respiratory distress. Skin contact with methylamine can lead to burns and dermatitis (Beard and Noe 1981). First aid for skin exposure requires immediate flushing with water.
Persons exposed to methylamine can detect a faint fishlike odor at less than 10 p.p.m. Little irritation occurs however, above 20 p.p.m. Methylamine can induce temporary irritation of the eyes, nose, and throat. The permissible exposure level (PEL) has been set at 10 p.p.m. (OSHA 1977) and the level immediately dangerous to life or health (IDLH) is 100 p.p.m. (Standards Completion Program, OSHA and NIOSH 1978).

Health Hazard

250 ppm produced damage to respiratorymucosa of the nasal turbinates. Exposureto 750 ppm produced severe body weightlosses, liver damage, and nasal degenerativechanges.
Any adverse health effects in humans dueto methylamine, other than its irritant action,is unknown.
LC50 value, inhalation (mice): 2400 mg/kg/2 h.

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.

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).

Safety Profile

Poison by subcutaneous route. Moderately toxic by inhalation. A severe skin irritant. Mutation data reported. A strong base. Flammable gas at ordinary temperature and pressure. Very dangerous fire hazard when exposed to heat, flame, or sparks. Explosive when exposed to heat or flame. To fight fire, stop flow of gas. Forms an explosive mixture with nitromethane. When heated to decomposition it emits toxic fumes of NOx. See also AMINES.

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.

First aid

If this chemical gets into the eyes, remove any contact lenses at once and irrigate immediately for at least 15 min, 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 Methylamine 1755 recommended for 2448 h after breathing overexposure, as pulmonary edema may be delayed. As first aid for pulmonary edema, a doctor or authorized paramedic may consider administering a corticosteroid spray.

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.

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.

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.

Incompatibilities

A medium-strong base. Reacts violently with strong acids; mercury, strong oxidizers; nitromethane. Corrosive to copper, zinc alloys; aluminum, and galvanized surfaces.

Waste Disposal

Return refillable compressed gas cylinders to supplier. Controlled incineration (incinerator equipped with a scrubber or thermal unit to reduce nitrogen oxides emissions).