Protic solvent

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In chemistry any solvent that carries hydrogen attached to oxygen as in a hydroxyl group, nitrogen as in an amine group, or, more generally, any molecular solvent which contains dissociable H⁺, such as hydrogen fluoride, is called a protic solvent. The molecules of such solvents can donate an H⁺ (proton). Conversely, aprotic solvents cannot donate hydrogen bonds.

Common characteristics of protic solvents:

• solvents display hydrogen bonding
• solvents have an acidic hydrogen (although they may be very weak acids)
• solvents are able to stabilise ions
  • cations by unshared free electron pairs
  • anions by hydrogen bonding

Examples are water, methanol, ethanol, formic acid, hydrogen fluoride and ammonia.

Polar aprotic solvents are solvents that share ion dissolving power with protic solvents but lack an acidic hydrogen. These solvents generally have high dielectric constants and high polarity.

examples are dimethyl sulfoxide, dimethylformamide, and hexamethylphosphorotriamide.

[edit] References

Loudon, G. Mark. Organic Chemistry 4th ed. New York: Oxford University Press. 2002. pg 317.