Why diethyl ether or furan is the specific solvent used in preparation of grignard reagent???

You see, furan is an enol and the ether which is usually used in Grignard as a solvent it is aprotic and can solvate the magnesium ion.

Why ether is used?

Well,

(A) It is aprotic solvent

What is aprotic?

A protic solvent is a solvent that has a hydrogen atom bound to an oxygen (as in a hydroxyl group) or a nitrogen (as in an amine group). In general terms, any solvent that contains H+ is called a protic solvent. The molecules of such solvents readily donate protons (H+) to reagents.

Conversely, aprotic solvents cannot donate hydrogen.

(B) Ether is a great solvating agent

The MgX bond in a Grignard reagent is ionic: R-Mg+lX−

Hence, it is difficult to form a Grignard reagent in a nonpolar solvent.

The C-O bond in an ether is quite polar, and the oxygen of the dipole can solvate and stabilize the R-Mg+ ion.

Regards

Arun (askIITians forum expert)