Protic solvent

"Protic" redirects here. For the surname, see Protić.

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

See also

• Autoprotolysis

References

1. Stoye, Dieter (2000). "Solvents". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a24_437. ISBN 3527306730.
2. John R. Rumble (ed.). "Laboratory Solvent Solvents and Other Liquid Reagents". CRC Handbook of Chemistry and Physics, 102nd Edition (Internet Version 2021). Boca Raton, FL, USA: CRC Press/Taylor & Francis.
3. W. L. F. Armarego (2017). Purification of Laboratory Chemicals, 8th Edition. Elsevier. ISBN 9780128054567.