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. Methods for purification of common solvents are available.
Solvent Chemical formula Boiling point Dielectric constant Density Dipole moment (D) Comment Polar aprotic solvents acetone(CH3)2CO56.1 °C 21.80.785 g/cm32.91reacts with strong acids and bases, somewhat protic due to keto-enol equilibrium and the unavoidable presence of water due to aldol condensation acetonitrile CH3CN 82 °C 38.30.776 g/cm3 3.20reacts with strong acids and bases dichloromethaneCH2Cl239.6 °C9.081.327 g/cm31.6low boiling point dimethylacetamide (CH3)2NCOCH3 165 °C37.8 0.94 g/cm3 3.72reacts with strong acids and bases dimethylformamide (CH3)2NCHO 153 °C36.7 0.95 g/cm3 3.86reacts with strong acids and bases N-methylpyrrolidoneCH3NCOC3H6203 °C32.3 1.028 g/cm34.09high boiling point dimethylimidazolidone(CH3N)2COC2H4225 °C37.6 1.056 g/cm34.09high boiling point dimethylpropyleneurea(CH3N)2COC3H6246.5 °C36.1 1.064 g/cm34.23high boiling point dimethyl sulfoxide (CH3)2SO 189 °C 46.7 1.10 g/cm3 3.96reacts with strong bases, difficult to purify ethyl acetateC2H5OCOCH377.1°C6.020.902 g/cm31.88reacts with strong bases hexamethylphosphoramide[(CH3)2N]3PO232.5 °C29.61.03 g/cm35.38 high boiling point, high toxicity propylene carbonate CH3C2H3O2CO 242 °C 64.9 1.205 g/cm3 4.94high boiling point pyridine C5H5N 115 °C 13.3 0.982 g/cm3 2.22 reacts with protic and Lewis acids sulfolane C4H8SO2 286 °C 43.3 1.27 g/cm3 4.8 high boiling point tetrahydrofuran C4H8O 66 °C 7.6 0.887 g/cm3 1.75polymerizes in presence of strong protic and Lewis acids
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