Index
It is part of a group of substances known as volatile organic compounds (VOCs).
Under normal conditions, methylamine is a colorless gas.
In high concentrations, it has a pungent odor. Methylamine is flammable. It is often found in solution with water and is also soluble in most organic (carbon-containing) solvents .
What is methylamine used for?
Methylamine is used to produce a variety of important chemicals:
- Pharmaceutical products.
- Fuel additive pesticides.
- Solvent explosives and cleaning agents.
- Chemicals for photographic pressing.
- Chemicals for leather tanning and dyeing processes.
Pharmaceutical products
Manufacturing intermediates to make pharmaceuticals is one of the most diverse uses for methylamines.
The reaction of monomethylamine and ethylene oxide creates two key intermediates: methyldiethanolamine (MDEA) and monomethylethanolamine (NMEA).
MDEA is used to make pain relievers with sedative and antispasmodic effects, such as meperidine.
The MMA reacted with phosgene or carbon dioxide to produce N, N-dimethylurea. This is used to make xanthine derivatives, such as caffeine and theophylline. The reaction of MMA and phenylsuccinic acid produces phensuximide, an anticonvulsant.
N-benzyl-n-methylamine is used in pharmaceuticals.
MMA is also used to make intermediates for chlordiazepoxide and lorazepam, antidepressants, nortriptylene antidepressant, veterinary smooth muscle relaxant isometheptene, iothalamic acid x-ray contrast medium, and levothyroxine.
Sympathomimetic drugs are made from MMA, such as epinephrine (3,4-dihydroxyphenyl chloromethyl ketone amination of pyrocatechol), epidrine (reductive amination of phenylmethyl diketone), neosinephrine, vannedrine, and veritol.
Dimethylamine is used to make DMAE, which has many uses to make pharmaceuticals. It is used to make antihistamines, such as pheniramine, chlorpheniramine, and diphenhydramine, for the symptomatic relief of allergies, such as hay fever.
DMAE is also used in the synthesis of local anesthetics, such as amethocaine, procaine, and pontocaine.
The pain reliever propoxyphene and the antidepressant doxepin are made from DMA. MMA and DMA salicylates are used as ointments for skin disorders. DMA is used to make intermediates for tranquilizing agents.
Another use for monomethylamine is to produce metam-sodium (n-methyldithiocarbamate), which is a fumigant and soil sterilant.
It is made from the reaction of MMA, carbon disulfide and caustic. Its applications are increasing, and it is currently used for potatoes, tomatoes, and home and garden applications.
It replaces methyl bromide as a soil fumigant, due to concerns that methyl bromide is a possible ozone depletor.
MMA is also manufactured to produce methyl isocyanate, which is used to make carbaryl, aldicarb, and trimethocarb. The insecticides carbofuran and carbosulfan are produced from these.
Monomethylformamide (MMF), made from MMA and carbon monoxide, is being used to make methyl isocyanate in situ, due to storage and transportation concerns of this highly toxic material.
MMF, sold by Chemours, can also be used as a solvent for other applications.
Dimethylamine is used to produce the herbicide 2,4-D (2,4-dichlorophenoxyacetic acid). Its DMA salt improves the water solubility of pesticide formulations.
Related agricultural products include the reaction of ferric with N, N-dimethyl dithiocarbamate to make ferbam, a fungicide for apples and tobacco.
The reaction of zinc to make ziram, a fungicide for vegetables; and thiram (tetramethylthiuram disulfide), a disinfectant for grains, bulbs, tubers, and corn.
Other DMA products include the herbicides diuron, linuron, hexazinone, and fluometuron.
Quaternary biocides are produced from alkyldimethylamine (from DMA) and dialkylmethylamine (from MMA). DMA salts reacted with substituted naphthaquinones are used to make miticides and hobbies.
DMA is also used to produce systemic insecticides such as octamethylpyrophosphoramide (OMPA) (schradan) that are absorbed into the plant and become toxic to mosquitoes.
Trimethylamine reacted with sulfur dioxide has been used to produce a volatile insecticide.
Animal Nutrients
The major use of trimethylamine (TMA) is in the production of choline chloride, a B vitamin supplement in animal feed for chickens, turkeys and pigs.
It is made from the reaction of TMA with hydrochloric acid and ethylene oxide or TMA and ethylene chlorohydrin to make this quaternary ammonium compound. The intermediate, TMA hydrochloride, has many uses in other industries as well, such as electronics.
Catalysts
Methylamines are used directly as catalysts or as raw materials to produce other compounds with catalytic activity. MDEA made from MMA is used as a urethane catalyst.
DMAE made from DMA is also used as a urethane catalyst to promote increased foam and gel strength for insulation applications such as refrigerators.
It is also used as a urethane catalyst. It is manufactured from the reaction of dimethylamine with acrylonitrile, followed by hydrogenation.
The hydrochlorides of MMA and DMA in the presence of cupric chloride are used for the polymerization of acetylene to vinyl and divinyl acetylene.
MMA and DMA are used as catalysts for the deodolization of diacetone alcohol. TMA is a catalyst for ethyl alcohol to ethylene oxide and for Diels-Alder diene association reactions.
DMA and calcium sulfate are used to prepare dinitroalkanes and nitroolefins. MMA and DMA can be used for the condensation of phenol and formaldehyde.
DMA is a catalyst for condensing acetone with formaldehyde to produce synthetic resins used in bonding and coating paper.
Explosives
Water gel explosives have been used in the mining industry because of their ease and safety in handling. The main ingredient is monomethylamine nitrate made from MMA, formaldehyde, and ammonium nitrate.
Mono, di, and trimethylamine perchlorates have also been used in the mining industry.
There have been some military uses for 2, 4, 6-trinitrophenylmethyl nitramine made from the nitration of dinitromethylaniline with nitric acid.
Dinitromethylaniline is the product of MMA plus dinitrochlorobenzene in the presence of caustic. Fuses have been manufactured from trimethylamine with nitric acid and nitroso perchlorate-paraffin mixtures.
Personal care
The personal care industry is an area with increasing use of methylamines as a raw material. N, N-dimethylaminopropylamine (DMAPA) and DMDAC are used to make cosmetics.
DMAPA is also an intermediate for betaines and fatty amide / amine oxides for liquid soaps.
DMAE is reacted in polymers for hair and cosmetic products, as well as in other personal care items such as hand lotions, shaving creams, and shampoos.
Resin manufacturing
Methylamines are used to make resins for the demineralization and deionization of water.
Cation exchange resins are made of trimethylamine reacted with polystyrene-chloromethylated divinylbenzene copolymers.
Anionic resins are made from the addition of dimethylamine and hydrochloric acid to the condensation products of melamine formaldehyde.
Water treatment
Dimethylamine is used as a raw material to produce suspended solids removal agents for water clarification in industrial, municipal, drinking and wastewater treatment plants.
They are used to improve solid / liquid separation in sedimentation, filtration and flotation operations.
Polyelectrolytic cationic flocculants made from DMA, such as dimethyldiallylammonium chloride (DMDAC) or epichlorohydrindimethylamine, are homopolymerized or copolymerized with acrylamide.
Additionally, DMA can be reacted with formaldehyde and polyacrylamide to make Mannich polymers. These polymers can be quaternized with dimethyl sulfate or methyl chloride to improve their performance at high pH.
Dimethylaminoethanol methacrylate-acrylamide copolymers (DMAE) are also used as cationic flocculants.
Where does methylamine come from?
Methylamine releases can occur during its manufacture and widespread uses in the chemical industry.
It is also produced naturally by some plants, is found in the urine of animals, and is released when animal or plant matter breaks down.
How could it affect the environment?
Methylamine is moderately toxic to wildlife. However, it breaks down quickly in the environment and therefore only very large releases (as a result of an accidental spill, for example) can cause damage.
Releases to water and soils will mainly evaporate to the atmosphere, where they decompose in a matter of days. Methylamine does not accumulate in the environment.
As a VOC, methylamine can be involved in the formation of ozone at ground level, which can damage crops and materials. Methylamine contamination is not considered likely to have any effect on the global environment.
How might exposure affect human health?
Methylamine can enter the body either by inhaling air containing methylamine, ingesting food or water containing methylamine, or by dermal contact with methylamine.
Breathing air that contains high levels of methylamine can cause various adverse health effects, including shortness of breath, burning sensation, sore throat, headache, and fluid build-up in the lungs (pulmonary edema).
Ingesting high levels of methylamine can cause esophagus and throat burns, a burning sensation, and abdominal pain. Dermal contact with methylamine can cause severe skin irritation and burns.
Contact with the eyes can cause severe burns and blurred vision. The International Agency for Research on Cancer has not designated methylamine in terms of its carcinogenicity.
What steps are being taken to limit potential impacts?
Methylamine emissions are controlled through the UK Pollution Prevention and Control (PPC) Regulations. Like VOCs, levels of methylamine in the air are also monitored through the UK’s National Air Quality Strategy.
It is also regulated by the European Solvents Directive (99/13 / EC).
The main international legislation regulating the levels of VOCs, such as methylamine, is the UN / UNECE Convention on Long-Range Transboundary Air Pollution and the Basel Convention on the Transboundary Movement and Disposal of Hazardous Wastes.
