A polar aprotic solvent is a solvent that lacks an acidic proton and is polar. Such solvents lack hydroxyl and amine groups. In contrast to protic solvents, these solvents do not serve as proton donors in hydrogen bonding, although they can be proton acceptors. Many solvents, including chlorocarbons and hydrocarbons, are classifiable as aprotic, but polar aprotic solvents are of particular interest for their ability to dissolve salts.[1][2] Methods for purification of common solvents are available.[3]
| Solvent | Chemical formula | Boiling point | Dielectric constant | Density | Dipole moment (D) | Comment |
|---|---|---|---|---|---|---|
| Polar aprotic solvents | ||||||
| acetone | C3H6O | 56.05 °C | 21.83 | 0.7845 g/cm3 | 2.91 | reacts with strong acids and bases |
| acetonitrile | CH3CN | 81.3 - 82.1 °C | 38.3 | 0.776 g/cm3 | 3.20 | reacts with strong acids and bases |
| dichloromethane | CH2Cl2 | 39.6 °C | 9.08 | 1.3266 g/cm3 | 1.6 | low boiling point |
| dimethylformamide | (CH3)2NCHO | 153 °C | 36.7 | 0.95 g/cm3 | 3.86 | reacts with strong bases |
| dimethylpropyleneurea | (CH3)2C4H6N2O | 246.5 °C | 36.12 | 1.064 g/cm3 | 4.23 | high boiling point |
| dimethyl sulfoxide | (CH3)2SO | 189 °C | 46.7 | 1.1 g/cm3 | 3.96 | reacts with strong bases, difficult to purify |
| ethyl acetate | C4H8O2 | 77.11°C | 6.02 | 0.902 g/cm3 | 1.88 | reacts with strong bases |
| hexamethylphosphoramide | [(CH3)2N]3PO | 232.5 °C | 29.6 | 1.03 g/cm3 | 5.38 | high boiling point, high toxicity |
| pyridine | C5H5N | 115 °C | 13.3 | 0.982 g/cm3 | 2.22 | reacts with protic and Lewis acids |
| sulfolane | C4H8SO2 | 286 °C | ? | 1.27 g/cm3 | 4.8 | high boiling point |
| tetrahydrofuran | C4H8O | 66 °C | 7.6 | 0.887 g/cm3 | 1.75 | polymerizes in presence of strong protic and Lewis acids |