Protic Solvent Vs Aprotic Solvent

Solvents are broadly classified into two types, polar and nonpolar solvents. Polar solvents are farther divided into protic and aprotic solvents.

Concisely, the difference between protic and aprotic solvents can exist written as:

"Protic solvents comprise at least one hydrogen atom connected directly to an electronegative atom (such equally F, N, O) and thus, tin can make hydrogen bonds. Whereas aprotic solvents do not contain any hydrogen atom connected directly to highly electronegative atoms and then are not capable of forming hydrogen bonds."

Protic vs aprotic solvents

Protic solvents	Aprotic solvents
Protic solvents have at to the lowest degree one hydrogen atom directly connected to an electronegative atom (N-H, O-H, etc)	Aprotic solvents tin have hydrogen atoms somewhere in their structures, just no hydrogen atom is straight connected to an electronegative atom
They are capable of hydrogen bonding	They cannot make hydrogen bonds
Protic solvents are acidic	Aprotic solvents are not acidic
They have high dielectric constants	They take intermediate and depression dielectric constants
Polar protic solvents are rich in O-H and N-H bonds	They lack O-H and N-H bonds
They are preferably used to deliquesce salts	Aprotic solvents tin can dissolve salts too. However, their power to dissolve salts depends mostly on the nature of the salts
SN1 reactions are significantly faster in protic solvents	SN1 reactions are dull in aprotic solvents
SN2 reactions are very slow in protic solvents	SN2 reactions are significantly faster in aprotic solvents
Polar protic solvents stabilize carbocations and nucleophiles	Polar aprotic solvents cannot hydrogen bond with nucleophiles
Water, alcohol, formic acid, hydrogen fluoride, ammonia, acetic acid, ethanol, methanol, etc. are all protic solvents	Acetone, dimethyl sulfoxide, HMF (hydroxymethylfurfural), crown ethers, DMF (North,N-dimethylformamide), acetonitrile, etc. are all aprotic solvents
Polar solvents requite hydrogen gas upon reduction and are therefore useful in reductive electrochemistry	Aprotic solvents are used in many industries including but not limited to oil and gas, paints and coatings, electronics, and pharmaceuticals

Similarities between protic and aprotic solvents

Both protic and aprotic solvents are polar solvents.
Both tin deliquesce salts.

What are protic solvents?

Mostly, any solvent with a labile H⁺ is the protic solvent. This proton is readily bachelor to solutes, ofttimes donated via hydrogen bonding. Water is the almost common protic solvent.

Hydrogen cantlet(s) is oftentimes bound to an oxygen atom, as in hydroxyl group, a nitrogen atom, equally in amine group, and fluoride, equally in hydrogen fluoride. These are the examples of polar protic solvents; Water (H₂O), formic acid (CH_iiO₂), hydrogen fluoride (HF), ethanol (C₂H_vOH), ammonia (NH₃), methanol (CH₃OH), acerb acid (CH₃COOH), etc.

What are aprotic solvents?

Aprotic solvents lack acidic protons. Thus, they cannot act equally proton donors in hydrogen bonding. Unlike polar solvents, they lack hydroxyl and amine groups.

Polar aprotic solvents are of particular interest because of their ability to dissolve salts, although they cannot donate protons. Many hydrocarbons and chlorocarbons are classified as aprotic solvents.

Some examples of aprotic solvents are acetone (H₃C-(C=O)-CH_iii), Ethyl acetate, DMSO, dimethyl sulphoxide ((CH₃)_twoSouthward=O), DMF, N,North-dimethylformamide (C_iiiH₇NO), HMF (hydroxymethylfurfural), Oxolane/tetrahydrofuran (THF), crown ethers, and acetonitrile (CH₃C≡N), etc.

Effect of protic and aprotic solvents on nucleophilic exchange

In protic solvents, anions are solvated due to the presence of hydrogen bonds, thus, their power to serve every bit a nucleophile is inhabited. On the other hand, anions are not solvated and there will be no event on the reaction charge per unit in aprotic solvents.

In general, these conclusions can be drawn from the above statement:

All nucleophiles tend to be more reactive in aprotic than protic solvents.
The species that are strongly solvated in polar protic solvents volition gain reactivity in polar aprotic e.g. F^–, etc.
Polar aprotic solvents are generally used when a polar protic solvent gives poor results due to weak nucleophiles such equally F^–, -CN, RCO₂ ^–, etc.

Key differences between protic and aprotic solvents

Concept Bergs

What does protic mean?

The give-and-take protic means, "of a solvent or other liquid medium, able to provide hydrogen atoms for the protonation".

Why is acetone considered a polar aprotic solvent?

Acetone is a polar aprotic solvent since information technology does not take whatever hydrogen atom straight attached to an electronegative atom (O).

Is dimethyl sulfoxide protic or aprotic?

Dimethyl sulfoxide (DMSO), CH₃SOCH_iii is a polar aprotic solvent as information technology does not contain a proton directly bonded to an electronegative cantlet but nonetheless, it is polar.

Why are aprotic solvents better for S_{Due north}2 reactions?

In aprotic solvents, nucleophiles are almost not-solvated then it is easier for them to attack the substrate. Hence, South_N2 reactions are favored in an aprotic environs, equally there is less hindrance to the nucleophiles. In protic environments, the nucleophiles are trapped in a cage of solvent molecules so get inactive.

Is benzene a protic solvent?

Benzene is a nonpolar solvent used for manufacturing a vast number of chemicals.

Is methanol a protic solvent?

Yes. Methanol is a polar protic solvent due to (O-H) reactivity.

Is ethanol protic or aprotic?

Ethanol is a polar protic solvent because of the (O-H) bond presence.

How do I identify whether a solvent is polar aprotic or protic?

Protic solvents take O-H and North-H bonds and they tin form hydrogen bonds. Aprotic solvents may have hydrogen atoms on them somewhere, but they are not directly attached to O or N (lack O-H or N-H bonds) and therefore cannot do hydrogen bonding.

Why does NaOH display the highest basic forcefulness in a polar protic solvent?

NaOH itself is a good base of operations. In protic solvents, O-H and Due north-H bonds are nowadays which act as proton donors and form strong hydrogen bonds. This results in the immediate dissociation of NaOH into its elective ions (Na⁺ and OH^–). NaOH liberates OH^– ions swiftly and thus, information technology exhibits its maximum strength in polar protic solvents.

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