Chemistry 9701 · AS & A Level · Organic synthesis

Organic synthesis — practice question

B is a liquid with a fruity odour. The reaction scheme shows the preparation of B from ethanol, $\text{C}_2\text{H}_5\text{OH}$.
(a(i))[2]

Reaction 1 is an oxidation reaction. Give the reagent(s) and conditions needed for reaction 1.

(a(ii))[1]

Construct an equation to represent reaction 1. Use $[\text{O}]$ to represent an oxygen atom from the oxidising agent in this reaction.

(a(iii))[1]

Suggest the type of reaction that occurs in reaction 2.

(a(iv))[1]

$\text{H}_2\text{SO}_4$ acts as a homogeneous catalyst in reaction 3. Explain why $\text{H}_2\text{SO}_4$ is described as homogeneous.

(b)[3]

Reaction 2 must be carried out without water present so that compound $C$ is not formed. If $C$ is included in the reaction mixture for reaction 3, a different compound, compound $D$, will also be produced. Compound $D$ has two identical functional groups. The infrared spectrum of $D$ has strong absorptions at $1100\,\text{cm}^{-1}$ and $1720\,\text{cm}^{-1}$, but no absorption caused by O-H bonds. Use the Data Booklet to identify the functional group present in $D$. Explain your answer as fully as you can.

(c(i))[1]

Draw the structure of E.

(c(ii))[1]

Suggest why $\text{NaBH}_4$ is not a suitable reagent to make F, $(\text{CH}_2\text{OH})_2$, from C. Explain your answer.

(c(iii))[1]

Construct an equation for the reaction of $(\text{CH}_2\text{OH})_2$ with $\text{SOCl}_2$ to form G, $(\text{CH}_2\text{Cl})_2$.

(d)[1]

Explain why C is very soluble in water.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Potassium dichromate(VI) or sodium dichromate(VI): $\mathrm{K_2Cr_2O_7}$ or $\mathrm{Na_2Cr_2O_7}$

  • Full mark scheme, point by point
  • Step-by-step worked solution
  • Write your answer & get it marked instantly by AI