This question is about making a diester from cyclohexanol - AQA - A-Level Chemistry - Question 8 - 2021 - Paper 2

The reagent needed for step 1 is concentrated sulfuric acid (H₂SO₄).

For step 2, the reagent needed is sodium hydroxide (NaOH). The equation for step 2 is:

$ext{Cyclohexene + NaOH} \rightarrow ext{product}$

For step 3, the reagent needed is ethanedioyl dichloride (ClCOCOCl). The equation for step 3 is:

$ext{Cyclohexane-1,2-diol + ClCOCOCl} \rightarrow ext{diester}$

The mechanism for this reaction is nucleophilic addition-elimination.

The mechanism involves the nucleophilic attack of the hydroxyl (-OH) group of cyclohexane-1,2-diol on the carbonyl carbon of ethanedioyl dichloride that leads to the formation of a tetrahedral intermediate, followed by elimination of HCl to form one ester link.

Fewer steps in production methods are preferred because they reduce production time and costs, leading to higher efficiency in manufacturing processes.

A high percentage atom economy is desirable as it minimizes waste and maximizes the use of reactants, thus making the process more sustainable and environmentally friendly.