Question

In an experiment of the dehydrobromination of meso-stilbene dibromide to form an alkyne:

A. Why is ethylene glycol used as a solvent in this reaction?
1. It forms a stable complex with the dibromostilbene and activates it towards elimination.
2. It acts the nucleophile in the reaction and leads to formation of the product.
3. It has a high enough boiling point such that it will not evaporate under the elevated reaction temperature.
4. It is the only solvent capable of dissolving the reagents.

Answer 1

3. It has a high enough boiling point such that it will not evaporate under the elevated reaction temperature.

Step-by-step explanation:

The dehydrobromination of meso-stilbene dibromide to form an alkyne requires a very high temperature to run, especially the second elimination reaction of H-Br from the alkene. Therefore, the ethylene glycol used in this reaction is necessary because it has a high enough boiling point such that it it will not evaporate under the elevated reaction temperature, creating complications.