Home / AS & A Level Chemistry 21.1 Organic synthesis: Exam Style Questions Paper 2

AS & A Level Chemistry 21.1 Organic synthesis: Exam Style Questions Paper 2

Question

Compounds J and K are found in plant oils.

(a) (i) Complete Table 4.1 to state what you would observe when J reacts with the reagents listed.

(ii) J has two optical isomers.Draw the three-dimensional structures of the two optical isomers of J.

(b) K is used to make the addition polymer Perspex®. A synthesis of Perspex® is shown in Fig. 4.2.

(i) Identify L. State the conditions required for reaction 1.
L =
conditions =
(ii) Draw one repeat unit of the addition polymer Perspex®.

(iii) Use information from Table 4.2 to suggest how the infrared spectra of M and Perspex® would differ. Explain your answer.


(iv) K can be made from propanone in the three-step synthesis shown in Fig. 4.3.

Complete Table 4.3 to identify the reagent(s) used and the type of reaction in each step.

Answer/Explanation

Answer:

(a) (i) red / orange / yellow precipitate / ppt / solid
silver mirror / silver / grey solid / precipitate / ppt
effervescence / bubbling / fizzing
(ii)

(b) (i)  L = \(CH_3OH\) / methanol
conditions = acid(ic) / H+ / \(H_2SO_4\) AND (heat under) reflux
(ii)

carbon backbone with ‘dangling’ bonds
rest of structure correct
(iii) Perspex® would not have absorption 1500 –1680 cm–1 AND Perspex® does not have C=C
(iv) step 1 KCN / HCN OR NaCN / \(H_2SO_4\)  addition
step 2 \(H^+ / H_2SO_4(aq)\)  hydrolysis / substitution
step 3 elimination / dehydration

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