Q29-E - Organic Chemistry (Mcmurry)

Question

In the formation of the prepolymer used to make epoxy resins, a bisphenol reacts with epichlorohydrin in the presence of a base. Show the product and mechanism when two moles of phenol react with epichlorohydrin.

Step-by-Step Solution

Answer

Mechanism followed as:

Step 1: Prepolymer

Prepolymer is usually a stable monomer that is a particularly polarised intermediate that can be further polarised for the formation of the product that leads to further polymerization in presence of reactive groups.

Step 2: Reaction of two moles of phenol with epichlorohydrin

Alcohol reaction with epichlorohydrin is followed by the alkoxide formation by the abstraction of proton followed by the ring-opening of the epoxide lead to the formation of the hydroxy group and then followed by the loss of water the desired product is obtained as given below:

                                                        Product formation

Step 3: Mechanism

The mechanism of the reaction followed as:

1. Abstraction of proton
2. Alkoxide formation
3. Addition of the epichlorohydrin
4. Ring-opening of the epoxide
5. Hydroxy formation occurs
6. loss of water
7. desired product formed

                                                Mechanism