Dimethylamine is an
organic compound with the formula (CH
3)
2NH. This
secondary amine
In chemistry, amines (, ) are compounds and functional groups that contain a basic nitrogen atom with a lone pair. Amines are formally derivatives of ammonia (), wherein one or more hydrogen atoms have been replaced by a substituent such ...
is a colorless, flammable gas with an
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
-like odor. Dimethylamine is commonly encountered commercially as a solution in water at concentrations up to around 40%. An estimated 270,000 tons were produced in 2005.
Structure and synthesis
The molecule consists of a
nitrogen atom with two
methyl
In organic chemistry, a methyl group is an alkyl derived from methane, containing one carbon atom bonded to three hydrogen atoms, having chemical formula . In formulas, the group is often abbreviated as Me. This hydrocarbon group occurs in man ...
substituents and one
proton. Dimethylamine is a
weak base
A weak base is a base that, upon dissolution in water, does not dissociate completely, so that the resulting aqueous solution contains only a small proportion of hydroxide ions and the concerned basic radical, and a large proportion of undissociat ...
and the
pKa
PKA may refer to:
* Professionally known as:
** Pen name
** Stage persona
* p''K''a, the symbol for the acid dissociation constant at logarithmic scale
* Protein kinase A, a class of cAMP-dependent enzymes
* Pi Kappa Alpha, the North-American so ...
of the
ammonium CH
3--CH
3 is 10.73, a value above
methylamine (10.64) and
trimethylamine
Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized ...
(9.79).
Dimethylamine reacts with acids to form salts, such as dimethylamine hydrochloride, an odorless white solid with a melting point of 171.5 °C. Dimethylamine is produced by
catalytic reaction of
methanol and
ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
at elevated temperatures and high pressure:
:2 CH
3OH + NH
3 → (CH
3)
2NH + 2 H
2O
Natural occurrence
Dimethylamine is found quite widely distributed in animals and plants, and is present in many foods at the level of a few mg/kg.
Uses
Dimethylamine is a precursor to several industrially significant compounds.
[ It reacts with ]carbon disulfide
Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical non ...
to give dimethyl dithiocarbamate, a precursor to zinc bis(dimethyldithiocarbamate)
Zinc dimethyldithiocarbamate is a coordination complex of zinc with dimethyldithiocarbamate. It is a pale yellow solid that is used as a fungicide, the sulfur vulcanization of rubber, and other industrial applications.
Applications
Known as zir ...
and other chemicals used in the sulfur vulcanization of rubber. The solvents dimethylformamide
Dimethylformamide is an organic compound with the formula ( CH3)2NC(O)H. Commonly abbreviated as DMF (although this initialism is sometimes used for dimethylfuran, or dimethyl fumarate), this colourless liquid is miscible with water and the major ...
and dimethylacetamide are derived from dimethylamine. It is raw material for the production of many agrichemical
An agrochemical or agrichemical, a contraction of ''agricultural chemical'', is a chemical product used in industrial agriculture. Agrichemical refers to biocides (pesticides including insecticides, herbicides, fungicides and nematicides) and sy ...
s and pharmaceuticals, such as dimefox
Dimefox was an organophosphate pesticide. In its pure form it is a colourless liquid with a fishy odour. Dimefox was first produced in 1940 by the group of Gerhard Schrader in Germany. It was historically used as a pesticide, but has been deemed ...
and diphenhydramine, respectively. The chemical weapon
A chemical weapon (CW) is a specialized munition that uses chemicals formulated to inflict death or harm on humans. According to the Organisation for the Prohibition of Chemical Weapons (OPCW), this can be any chemical compound intended as a ...
tabun is derived from dimethylamine. The surfactant lauryl dimethylamine oxide is found in soaps and cleaning compounds. Unsymmetrical dimethylhydrazine
Unsymmetrical dimethylhydrazine (UDMH; 1,1-dimethylhydrazine, НДМГ or codenamed Geptil) is a chemical compound with the formula H2NN(CH3)2 that is used as a rocket propellant. It is a colorless liquid, with a sharp, fishy, ammonia-like smell ...
, a rocket fuel, is prepared from dimethylamine.
:(CH3)2NH + NH2Cl → (CH3)2NNH2 ⋅ HCl
Reactions
It is basic, in both the Lewis and Brønsted senses. It easily forms dimethylammonium salts upon treatment with acids. Deprotonation of dimethylamine can be effected with organolithium compound
In organometallic chemistry, organolithium reagents are chemical compounds that contain carbon–lithium (C–Li) bonds. These reagents are important in organic synthesis, and are frequently used to transfer the organic group or the lithium atom ...
s. The resulting LiNMe2, which adopts a cluster-like structure, serves as a source of "Me2N−". This lithium amide has been used to prepare volatile metal complexes such as tetrakis(dimethylamido)titanium
Tetrakis(dimethylamino)titanium (TDMAT) is a chemical compound. The compound is generally classified as a metalorganic species, meaning that its properties are strongly influenced by the organic ligands but the compound lacks metal-carbon bonds. It ...
and pentakis(dimethylamido)tantalum.
It is also a Lewis base.
It reacts with many carbonyl compounds. Aldehydes give aminals. For example reaction of dimethylamine and formaldehyde gives bis(dimethylamino)methane
Bis(dimethylamino)methane is the organic compound with the formula CH3)2Nsub>2CH2. It is classified as an aminal as well as a ditertiary amine, in fact the simplest. It is a colorless liquid that is widely available. It is prepared by the react ...
:
: 2 (CH3)2NH + CH2O → 3)2N">CH3)2Nsub>2CH2 + H2O
It converts esters to dimethylamides.
Dimethylamine undergoes nitrosation
Nitrosation is a process of converting organic compounds into nitroso derivatives, i.e. compounds containing the R-NO functionality.
''C''-Nitroso compounds
''C''-Nitroso compounds, such as nitrosobenzene, are typically prepared by oxidation of ...
to give dimethylnitrosamine, a carcinogen.
Occurrence
It is an attractant for boll weevil
The boll weevil (''Anthonomus grandis'') is a beetle that feeds on cotton buds and flowers. Thought to be native to Central Mexico, it migrated into the United States from Mexico in the late 19th century and had infested all U.S. cotton-growing ...
s.[''The Merck Index, 10th Ed.'' (1983), p.470, Rahway: Merck & Co.]
Safety
Dimethylamine is not very toxic with the following LD50 values: 736 mg/kg (mouse, i.p.); 316 mg/kg (mouse, p.o.); 698 mg/kg (rat, p.o.); 3900 mg/kg (rat, dermal); 240 mg/kg (guinea pig or rabbit, p.o.).[Chemical Information Profile for Dimethylamine Borane, National Toxicology Program, NIEHS, NIH (2008), p.4: http://ntp.niehs.nih.gov/ntp/htdocs/Chem_Background/ExSumPdf/DimethylamineBorane508.pdf]
See also
* Methylamine
*Trimethylamine
Trimethylamine (TMA) is an organic compound with the formula N(CH3)3. It is a colorless, hygroscopic, and flammable tertiary amine. It is a gas at room temperature but is usually sold as a 40% solution in water. (It is also sold in pressurized ...
References
External links
* (gas)
* (aqueous solution)
*
Properties
from Air Liquide
* MSDS a
airliquide.com
{{Authority control
Alkylamines
Insect pheromones
Insect ecology
Secondary amines