 | |
 | |
| Names | |
|---|---|
| Preferred IUPAC name N,N-Dimethylacetamide | |
| Identifiers | |
| |
3D model (JSmol) | |
| Abbreviations | DMA, DMAC, DMAc[1] |
| 1737614 | |
| ChEBI | |
| ChEMBL | |
| ChemSpider |
|
| ECHA InfoCard | 100.004.389 |
| EC Number |
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| MeSH | dimethylacetamide |
| RTECS number |
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| UNII | |
| |
| |
| Properties | |
| C4H9NO | |
| Molar mass | 87.122 g·mol−1 |
| Appearance | Colorless liquid |
| Odor | Ammoniacal |
| Density | 0.937 g/mL |
| Melting point | −20 °C (−4 °F; 253 K) |
| Boiling point | 165.1 °C; 329.1 °F; 438.2 K |
| Miscible | |
| logP | −0.253 |
| Vapor pressure | 300 Pa |
| UV-vis (λmax) | 270 nm |
Refractive index (nD) | 1.4375 |
| Viscosity | 0.945 mPa·s[2] |
| Thermochemistry | |
| 178.2 J/(K·mol) | |
Std enthalpy of formation(ΔfH⦵298) | −300.1 kJ/mol |
Std enthalpy of combustion(ΔcH⦵298) | −2.5835–−2.5805 MJ/mol |
| Hazards | |
| GHS labelling: | |
  | |
| Danger | |
| H312,H319,H332,H360 | |
| P280,P308+P313 | |
| NFPA 704 (fire diamond) | |
| Flash point | 63 °C (145 °F; 336 K) |
| 490 °C (914 °F; 763 K) | |
| Explosive limits | 1.8–11.5% |
| Lethal dose or concentration (LD, LC): | |
LD50 (median dose) | 2.24 g/kg(dermal, rabbit) 4.3 g/kg(oral, rat) 4.8 g/kg (oral, rat) 4.62 g/kg (oral, mouse)[4] |
LC50 (median concentration) | 2475 ppm (rat, 1 h)[4] |
| NIOSH (US health exposure limits): | |
PEL (Permissible) | TWA 10 ppm (35 mg/m3) [skin][3] |
REL (Recommended) | TWA 10 ppm (35 mg/m3) [skin][3] |
IDLH (Immediate danger) | 300 ppm[3] |
| Related compounds | |
Related compounds | |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
Dimethylacetamide (DMAc orDMA) is theorganic compound with theformula CH3C(O)N(CH3)2. This colorless, water-miscible, high-boiling liquid is commonly used as a polarsolvent inorganic synthesis. DMA is miscible with most other solvents, although it is poorly soluble inaliphatichydrocarbons.
DMA is prepared commercially by the reaction ofdimethylamine withacetic anhydride oracetic acid. Dehydration of the salt of dimethylamine and acetic acid also furnishes this compound:[5]
Dimethylacetamide can also be produced by the reaction ofdimethylamine withmethyl acetate.[6]
The separation and purification of the product is carried out by multistagedistillation in rectification columns. DMA is obtained with essentially quantitive (99%)yield referred to methyl acetate.[6]
The chemical reactions of dimethylacetamide are typical ofN,N-disubstitutedamides.Hydrolysis of the acyl-N bond occurs in the presence ofacids:
However, it is resistant to bases. For this reason DMA is a useful solvent for reactions involving strong bases such assodium hydroxide.[7]
Dimethylacetamide is commonly used as a solvent for fibers (e.g.,polyacrylonitrile,spandex) or in theadhesive industry.[5] It is also employed in the production ofpharmaceuticals andplasticizers as a reaction medium.
A solution oflithium chloride in DMAc (LiCl/DMAc) can dissolvecellulose. Unlike many other cellulose solvents, LiCl/DMAc gives a molecular dispersion, i.e. a "true solution". For this reason, it is used ingel permeation chromatography to determine themolar mass distribution of cellulose samples.
Dimethylacetamide is also used as anexcipient in drugs, e.g. in Vumon (teniposide), Busulfex (busulfan) or Amsidine (amsacrine).
Dimethylacetamide, like most simple alkyl amides, is of low acute toxicity. Chronic exposure can causehepatotoxicity.[8][9][10][11] At high doses (400 mg/kg body mass daily), dimethylacetamide causes effects on thecentral nervous system (e.g.depression,hallucinations anddelusion).[8][12][13]
Dimethylacetamide may be incompatible withpolycarbonate orABS. Devices (e.g. syringes) that contain polycarbonate or ABS can dissolve when coming into contact with dimethylacetamide.[14]
In 2011, dimethylacetamide was identified in the EU as aSubstance of very high concern (SVHC) because of itsreproductive toxicity.[15] In 2014, the European Commission has started an investigation to restrict the use of dimethylacetamide in the EU according toREACH.[16]
In 2015, the CNESST (Committee on Standards, Equity, Health and Safety at Work inQuebec) has adopted a tightened classification of dimethylacetamide:[17]
| Description | Category | GHS hazard statement |
|---|---|---|
| Reproductive toxicity | 2 | Suspected of damaging fertility or the unborn child (H361) |
| Specific target organ toxicity – repeated exposure | 2 | May cause damage to organs through prolonged or repeated exposure (H373) |
| Serious eye damage/eye irritation | 2 | Causes serious eye irritation (H319) |
| Acute toxicity – inhalation | 3 | Toxic if inhaled (H331) |
| Specific target organ toxicity – single exposure – narcotic effects | 3 | May cause drowsiness or dizziness (H336) |
| Flammable liquid | 4 | Combustible liquid (H227) |
