In chemistry, a protic solvent is a solvent that has a hydrogen atom bound to an oxygen (as in a hydroxyl group −OH), a nitrogen (as in an amine group −NH2 or −NH−), or fluoride (as in hydrogen fluoride). In general terms, any solvent that contains a labile H+ is called a protic solvent. The molecules of such solvents readily donate protons (H+) to solutes, often via hydrogen bonding. Water is the most common protic solvent. Conversely, polar aprotic solvents cannot donate protons but still have the ability to dissolve many salts.[1][2]
Methods for purification of common solvents are available[3]
| Solvent | Chemical formula | Boiling point | Dielectric constant | Density | Dipole moment (D) |
|---|---|---|---|---|---|
| Polar protic solvents | |||||
| formic acid | HCO2H | 101 °C | 58 | 1.21 g/mL | 1.41 D |
| n-butanol | CH3CH2CH2CH2OH | 118 °C | 18 | 0.810 g/mL | 1.63 D |
| isopropanol (IPA) | (CH3)2CH(OH) | 82 °C | 18 | 0.785 g/mL | 1.66 D |
| nitromethane [note 2] | CH3NO2 | 101°C | 35.87 | 1.1371 g/mL | 3.56 D |
| ethanol (EtOH) | CH3CH2OH | 79 °C | 24.55 | 0.789 g/mL | 1.69 D |
| methanol (MeOH) | CH3OH | 65 °C | 33 | 0.791 g/mL | 1.70 D |
| Acetic acid (AcOH) | CH3CO2H | 118 °C | 6.2 | 1.049 g/mL | 1.74 D |
| Water | H2O | 100 °C | 80 | 1.000 g/mL | 1.85 D |