Question

Show the role of each ether solvent (diethyl ether, THF and Crown Ether) in reactions by matching them with the corresponding process. (i) alcohol from alkenes (ii)SN2 reaction (iii) alcohol from carbonyl compounds.

A) Diethyl ether with MgBr trapped in between the two ether

B) Tetrahydrofuran (THF) with BH3 attached to the Oxygen in the THF.

C) 18-Crown-6 with potassium (K) trapped in there and Iodine on the outside of the two molecules.

2) Is the interaction between the ether and alcohol molecules showing the hydrogen bond?

Answer 1

Solution:

Crown ethers are used because it strongly bind with K+ ion and forming the complexes.

Diethylether is used to stabilized the grignard reagent.

THF solvent used to stabilized BH3 because BH3 is highly reactive.

i) Alcohol from alkenes: B) : THF with BH3 attached to oxygen in the THF

ii) SN2 reaction: C) 18 crown:6 with K trapped and iodine on the other side

iii) Alcohol from carbonyl compounds : A): Diethyl ether with mgBr trapped in between the two ether.

2) Yes

Ethers have nonbonding electron pairs on their oxygen atoms hence they can form hydrogen bonds with H atom of OH group of alcohol.