Polar Protic and Polar Aprotic Solvents

What Do You Mean by Polar Protic Solvent and Polar Aprotic Solvent? What are Some Examples of These?

Polar Protic solvents are polar solvents that have at least 1 hydrogen that is connected directly to a particular electronegative atom such as O-H, N-H, etc. The polar protic solvents are capable of forming Hydrogen bonds. However protic solvents are mostly acidic and have rather high dielectric constants. These solvents are mostly rich in N-H and O-H bonds. These solvents are also preferably used for dissolving salts. Here it should be mentioned that SN1 reactions are faster whereas SN2 reactions are slower in polar protic solvents. An important property of protic solvents is that they give Hydrogen gas on reduction which is highly useful in reductive chemistry. They also facilitate the stabilizations of nucleophiles and carbocations. Different well-known examples of polar protic solvents include alcohol, water, hydrogen fluoride, formic acid, acetic acid, ammonia, methanol, ethanol, etc. 

On the contrary polar aprotic solvents do not have acidic protons and so they do not act as donors during Hydrogen bonding. Their dielectric constants are intermediate and low. Unlike polar protic solvents, they do not have N-H bonds and O-H bonds. Similar to protic solvents, aprotic solvents are capable of dissolving various salts, however, unlike protic solvents, their ability to dissolve salt depends on the salt’s nature. In aprotic solvents, SN2 reactions are faster whereas SN1 reactions are comparatively slow. Aprotic solvents are used in different industries such as gas and oil, coatings and paints, pharmaceuticals, and electronics. Different well-known examples of Aoprotic solvents are Acetone, crown Ethers, Dimethyl sulfoxide, acetonitrile, DMF, HMF, etc.