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| Names | |
|---|---|
| Preferred IUPAC name 2-(Methylamino)ethan-1-ol | |
Other names
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| Identifiers | |
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3D model (JSmol) | |
| 1071196 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
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| ECHA InfoCard | 100.003.374 |
| EC Number |
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| MeSH | N-methylaminoethanol |
| RTECS number |
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| UNII | |
| UN number | 2735 |
| |
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| Properties | |
| C3H9NO | |
| Molar mass | 75.111 g·mol−1 |
| Appearance | Colourless liquid |
| Odor | Ammoniacal |
| Density | 0.935 g mL−1 |
| Melting point | −4.50 °C; 23.90 °F; 268.65 K |
| Boiling point | 158.1 °C; 316.5 °F; 431.2 K |
| Miscible | |
| logP | 1.062 |
| Vapor pressure | 70 Pa (at 20 °C) |
Refractive index (nD) | 1.439 |
| Hazards | |
| GHS labelling: | |
  | |
| Danger | |
| H302,H312,H314 | |
| P280,P305+P351+P338,P310 | |
| Flash point | 76 °C (169 °F; 349 K) |
| 350 °C (662 °F; 623 K) | |
| Explosive limits | 1.6–19.8% |
| Related compounds | |
Related alkanols | |
Related compounds | Diethylhydroxylamine |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
N-Methylethanolamine is analkanolamine with the formula CH3NHCH2CH2OH. It isflammable,corrosive, colorless,viscousliquid.[2] It is an intermediate in thebiosynthesis ofcholine.
With both anamine and ahydroxylfunctional groups, it is a useful intermediate in thechemical synthesis of various products including polymers and pharmaceuticals. It is also used as asolvent, for example in the processing ofnatural gas, where it is used together with its analogsethanolamine anddimethylethanolamine.
N-Methylethanolamine is produced industrially by reactingethylene oxide with excessmethylamine in aqueous solution. This reaction yields a mixture of the 1:1 addition product NMEA (1) and - by a further addition of another ethylene oxide - the 1:2 addition productmethyl diethanolamine (MDEA) (2):
In order to obtain high yields of the desired target product, the reactants are continuously fed to a flow reactor and reacted with a more than two-fold excess of methylamine.[3] In the downstream process steps, the excess methylamine and the water is removed and NMEA (bp. 160 °C) and MDEA (bp. 243 °C) are isolated from the product mixture by fractional distillation. The poly(methyl-ethanolamine) formed by further addition of ethylene oxide to methylethanolamine remains in the distillation bottoms.
N-Methylethanolamine is a clear, colorless,hygroscopic, amine-like smelling liquid which is miscible with water and ethanol in any ratio. Aqueous solutions react strongly basic and are therefore corrosive. The substance is easily biodegradable and has no potential ofbioaccumulation due to its water miscibility. NMEA is not mutagenic, but in the presence ofnitrite, carcinogenicnitrosamines can be formed from the compound, as it is a secondary amine.[4]
Like other alkylalkanolamines,N-methylethanolamine is used in water- and solvent-based paints and coatings as a solubilizer for other components, such as pigments and as a stabilizer.
Incathodic dip-coating,N-methylaminoethanol serves as cation neutralizer for the partial neutralization of theepoxy resin. It also serves as a chain extender in the reaction of high molecular weight polyepoxides withpolyols.
Being a base,N-methylaminoethanol forms neutral salts withfatty acids, which are used as surfactants (soaps) with good emulsifying properties and find applications in textile and personal care cleansing products. When bleaching cotton-polyester blends, NMEA is used as a brightener.[5]
By methylation ofN-methylaminoethanol,dimethylaminoethanol andcholine [(2-hydroxyethyl)-trimethyl-ammonium chloride] can be prepared.
In the reaction ofN-methylaminoethanol with fatty acids, long-chainN-methyl-N-(2-hydroxyethyl)amides are formed upon elimination of water. These are used as neutral surfactants. Such amides also act as flow improvers andpour point depressants inheavy oils andmiddle distillates.[6]By catalytic oxidation ofN-methylaminoethanol, thenon-proteinogenic amino acidsarcosine is obtained.[7]
N-methylaminoethanol plays a role as abuilding block for the synthesis of crop protection compounds and pharmaceuticals, such as in the first stage of the reaction sequence to the antihistamine andantidepressantmianserin (Tolvin) and to the non-analgesicNefopam (Ajan).[8]
In analogy to otheraziridines,N-methylaziridine can be obtained by aWenker synthesis fromN-methylaminoethanol. This is done either via the sulfuric acid ester or after replacement of thehydroxy group by a chlorine atom (for example bythionyl chloride orchlorosulfuric acid[9]) toN-methyl-2-chloroethylamine and then by using a strong base (cleavage of HCl) in anintramolecular nucleophilic substitution:
It reacts withcarbon disulfide to giveN-methyl-2-thiazolidinethione.
