Methylamine
Encyclopedia
Methylamine is the organic compound
with a formula
of CH3NH2. This colourless gas is a derivative of ammonia
, but with one H atom replaced by a methyl group. It is the simplest primary amine
. It is sold as a solution in methanol
, ethanol
, THF
, and water
, or as the anhydrous
gas in pressurized metal containers. Industrially methylamine is sold in its anhydrous form in pressurized railcars and tank trailers. It has a strong odor similar to fish. Methylamine is used as a building block for the synthesis of many other commercially available compounds. Over 1 million tonnes are produced annually.
with methanol
in the presence of a silicoaluminate catalyst. Dimethylamine
and trimethylamine
are coproduced; the reaction kinetics and reactant ratios determine the ratio of the three products.
In this way, more than 400M kg are produced annually.
In the laboratory, methylamine hydrochloride
is readily prepared by treating formaldehyde
with ammonium chloride
.
The colourless hydrochloride salt can be converted to the amine by the addition of strong base, like NaOH:
Methylamine was first prepared by Wurtz
by the hydrolysis of methyl isocyanate
and related compounds.
as it is highly basic and unhindered, although, as an amine
it is considered a weak base
. Its use in organic chemistry
is pervasive. Some reactions involving simple reagents include: with phosgene to methyl isocyanate
, with carbon disulfide
and sodium hydroxide to the sodium methyldithiocarbamate, with chloroform and base to methyl isocyanide
and with ethylene oxide
to methylethanolamines.
Representative commercially significant chemicals produced from methylamine include the pharmaceuticals ephedrine
and theophylline
, the pesticides carbofuran
, carbaryl
, and metham sodium
, and the solvents N-methylformamide and N-methylpyrrolidone
. The preparation of some surfactants and photographic developers require methylamine as a building block.
Liquid methylamine can be used as a solvent analogous to liquid ammonia. It shares some of the properties of liquid ammonia, but is better for dissolving organic substances, in the same way that methanol
is better than water
. Methylamine can also be used for scavenging H2S
from hydrocarbon in refining applications.
and is a substrate for methanogenesis
. It serves as a buffering agent
in the lumen of the chloroplast
in plants, effectively siphoning off protons that are heading for ATP synthase
.
lists methylamine as a precursor (to methamphetamine
).
Organic compound
An organic compound is any member of a large class of gaseous, liquid, or solid chemical compounds whose molecules contain carbon. For historical reasons discussed below, a few types of carbon-containing compounds such as carbides, carbonates, simple oxides of carbon, and cyanides, as well as the...
with a formula
Chemical formula
A chemical formula or molecular formula is a way of expressing information about the atoms that constitute a particular chemical compound....
of CH3NH2. This colourless gas is a derivative of ammonia
Ammonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
, but with one H atom replaced by a methyl group. It is the simplest primary amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
. It is sold as a solution in methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
, ethanol
Ethanol
Ethanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
, THF
ThF
Follicular B helper T cells , are antigen-experienced CD4+ T cells found in the B cell follicles of secondary lymphoid organs such as lymph nodes, spleens and Peyer's patches, and are identified by their constitutive expression of the B cell follicle homing receptor CXCR5...
, and water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
, or as the anhydrous
Anhydrous
As a general term, a substance is said to be anhydrous if it contains no water. The way of achieving the anhydrous form differs from one substance to another...
gas in pressurized metal containers. Industrially methylamine is sold in its anhydrous form in pressurized railcars and tank trailers. It has a strong odor similar to fish. Methylamine is used as a building block for the synthesis of many other commercially available compounds. Over 1 million tonnes are produced annually.
Production
Methylamine is prepared commercially by the reaction of ammoniaAmmonia
Ammonia is a compound of nitrogen and hydrogen with the formula . It is a colourless gas with a characteristic pungent odour. Ammonia contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to food and fertilizers. Ammonia, either directly or...
with methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
in the presence of a silicoaluminate catalyst. Dimethylamine
Dimethylamine
Dimethylamine is an organic compound with the formula 2NH. This secondary amine is a colorless, flammable liquified gas with an ammonia-like odor. Dimethylamine is generally encountered as a solution in water at concentrations up to around 40%...
and trimethylamine
Trimethylamine
Trimethylamine is an organic compound with the formula N3. This colorless, hygroscopic, and flammable tertiary amine has a strong "fishy" odor in low concentrations and an ammonia-like odor at higher concentrations...
are coproduced; the reaction kinetics and reactant ratios determine the ratio of the three products.
- CH3OH + NH3 → CH3NH2 + H2O
In this way, more than 400M kg are produced annually.
In the laboratory, methylamine hydrochloride
Hydrochloride
In chemistry, hydrochlorides are salts resulting, or regarded as resulting, from the reaction of hydrochloric acid with an organic base . This is also known as muriate, derived from hydrochloric acid's other name: muriatic acid....
is readily prepared by treating formaldehyde
Formaldehyde
Formaldehyde is an organic compound with the formula CH2O. It is the simplest aldehyde, hence its systematic name methanal.Formaldehyde is a colorless gas with a characteristic pungent odor. It is an important precursor to many other chemical compounds, especially for polymers...
with ammonium chloride
Ammonium chloride
Ammonium chloride NH4Cl is an inorganic compound with the formula NH4Cl. It is a white crystalline salt that is highly soluble in water. Solutions of ammonium chloride are mildly acidic. Sal ammoniac is a name of natural, mineralogical form of ammonium chloride...
.
- NH4Cl + H2CO → [CH2=NH2]Cl + H2O
- [CH2=NH2]Cl + H2CO + H2O → [CH3NH3]Cl + HCOOHFormic acidFormic acid is the simplest carboxylic acid. Its chemical formula is HCOOH or HCO2H. It is an important intermediate in chemical synthesis and occurs naturally, most notably in the venom of bee and ant stings. In fact, its name comes from the Latin word for ant, formica, referring to its early...
The colourless hydrochloride salt can be converted to the amine by the addition of strong base, like NaOH:
- [CH3NH3]Cl + NaOH → CH3NH2 + NaCl + H2O
Methylamine was first prepared by Wurtz
Charles-Adolphe Wurtz
Adolphe Wurtz was an Alsatian French chemist. He is best remembered for his decades-long advocacy for the atomic theory and for ideas about the structures of chemical compounds, against the skeptical opinions of chemists such as Marcellin Berthelot and Etienne Henri Sainte-Claire Deville...
by the hydrolysis of methyl isocyanate
Methyl isocyanate
Methyl isocyanate is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane, methyl carbylamine, and MIC. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides . It has also been used in the production of rubbers and adhesives...
and related compounds.
Reactivity and applications
Methylamine is a good nucleophileNucleophile
A nucleophile is a species that donates an electron-pair to an electrophile to form a chemical bond in a reaction. All molecules or ions with a free pair of electrons can act as nucleophiles. Because nucleophiles donate electrons, they are by definition Lewis bases.Nucleophilic describes the...
as it is highly basic and unhindered, although, as an amine
Amine
Amines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are derivatives of ammonia, wherein one or more hydrogen atoms have been replaced by a substituent such as an alkyl or aryl group. Important amines include amino acids, biogenic amines,...
it is considered a weak base
Weak base
In chemistry, a weak base is a chemical base that does not ionize fully in an aqueous solution. As Brønsted–Lowry bases are proton acceptors, a weak base may also be defined as a chemical base in which protonation is incomplete. This results in a relatively low pH compared to strong bases...
. Its use in organic chemistry
Organic chemistry
Organic chemistry is a subdiscipline within chemistry involving the scientific study of the structure, properties, composition, reactions, and preparation of carbon-based compounds, hydrocarbons, and their derivatives...
is pervasive. Some reactions involving simple reagents include: with phosgene to methyl isocyanate
Methyl isocyanate
Methyl isocyanate is an organic compound with the molecular formula CH3NCO. Synonyms are isocyanatomethane, methyl carbylamine, and MIC. Methyl isocyanate is an intermediate chemical in the production of carbamate pesticides . It has also been used in the production of rubbers and adhesives...
, with carbon disulfide
Carbon disulfide
Carbon disulfide is a colorless volatile liquid with the formula CS2. The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non-polar solvent...
and sodium hydroxide to the sodium methyldithiocarbamate, with chloroform and base to methyl isocyanide
Isocyanide
An isocyanide is an organic compound with the functional group -N≡C. It is the isomer of the related cyanide , hence the prefix iso....
and with ethylene oxide
Ethylene oxide
Ethylene oxide, also called oxirane, is the organic compound with the formula . It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape . This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered...
to methylethanolamines.
Representative commercially significant chemicals produced from methylamine include the pharmaceuticals ephedrine
Ephedrine
Ephedrine is a sympathomimetic amine commonly used as a stimulant, appetite suppressant, concentration aid, decongestant, and to treat hypotension associated with anaesthesia....
and theophylline
Theophylline
Theophylline, also known as dimethylxanthine, is a methylxanthine drug used in therapy for respiratory diseases such as COPD and asthma under a variety of brand names. Because of its numerous side-effects, the drug is now rarely administered for clinical use. As a member of the xanthine family, it...
, the pesticides carbofuran
Carbofuran
Carbofuran is one of the most toxic carbamate pesticides. It is marketed under the trade names Furadan, by FMC Corporation and Curater, among several others. It is used to control insects in a wide variety of field crops, including potatoes, corn and soybeans...
, carbaryl
Carbaryl
Carbaryl is a chemical in the carbamate family used chiefly as an insecticide. It is a white crystalline solid commonly sold under the brand name Sevin, a trademark of the Bayer Company. Union Carbide discovered carbaryl and introduced it commercially in 1958...
, and metham sodium
Metham sodium
Metham sodium is a soil fumigant used as a pesticide, herbicide, and fungicide. It is one of the most widely used pesticides in the United States, with approximately 60 million pounds used in 2001...
, and the solvents N-methylformamide and N-methylpyrrolidone
Methylpyrrolidone
N-Methyl-2-pyrrolidone is a chemical compound with 5-membered lactam structure. It is a clear to slightly yellow liquid miscible with water and solvents like ethyl acetate, chloroform, benzene and lower alcohols or ketones. It also belongs to the class of dipolar aprotic solvents which includes...
. The preparation of some surfactants and photographic developers require methylamine as a building block.
Liquid methylamine can be used as a solvent analogous to liquid ammonia. It shares some of the properties of liquid ammonia, but is better for dissolving organic substances, in the same way that methanol
Methanol
Methanol, also known as methyl alcohol, wood alcohol, wood naphtha or wood spirits, is a chemical with the formula CH3OH . It is the simplest alcohol, and is a light, volatile, colorless, flammable liquid with a distinctive odor very similar to, but slightly sweeter than, ethanol...
is better than water
Water
Water is a chemical substance with the chemical formula H2O. A water molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state . Water also exists in a...
. Methylamine can also be used for scavenging H2S
Hydrogen sulfide
Hydrogen sulfide is the chemical compound with the formula . It is a colorless, very poisonous, flammable gas with the characteristic foul odor of expired eggs perceptible at concentrations as low as 0.00047 parts per million...
from hydrocarbon in refining applications.
Biological chemistry
Methylamine arises naturally as the result of putrefactionPutrefaction
Putrefaction is one of seven stages in the decomposition of the body of a dead animal. It can be viewed, in broad terms, as the decomposition of proteins, in a process that results in the eventual breakdown of cohesion between tissues and the liquefaction of most organs.-Description:In terms of...
and is a substrate for methanogenesis
Methanogenesis
Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with...
. It serves as a buffering agent
Buffering agent
A buffering agent is a weak acid or base used to maintain the acidity of a solution at a chosen value. The function of a buffering agent is to prevent a rapid change in pH when acids or bases are added to the solution. Buffering agents have variable properties—some are more soluble than others;...
in the lumen of the chloroplast
Chloroplast
Chloroplasts are organelles found in plant cells and other eukaryotic organisms that conduct photosynthesis. Chloroplasts capture light energy to conserve free energy in the form of ATP and reduce NADP to NADPH through a complex set of processes called photosynthesis.Chloroplasts are green...
in plants, effectively siphoning off protons that are heading for ATP synthase
ATP synthase
right|thumb|300px|Molecular model of ATP synthase by X-ray diffraction methodATP synthase is an important enzyme that provides energy for the cell to use through the synthesis of adenosine triphosphate . ATP is the most commonly used "energy currency" of cells from most organisms...
.
Safety
The LD50 (mouse) is 2400 mg/m3. Methylamine is also controlled as a List 1 substance by the United States Drug Enforcement Administration (DEA); the DEADrug Enforcement Administration
The Drug Enforcement Administration is a federal law enforcement agency under the United States Department of Justice, tasked with combating drug smuggling and use within the United States...
lists methylamine as a precursor (to methamphetamine
Methamphetamine
Methamphetamine is a psychostimulant of the phenethylamine and amphetamine class of psychoactive drugs...
).