OCR A Jun 2014 Paper 4 Q1

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Answer all the questions. 1 Salicylic acid is a naturally occurring carboxylic acid, widely used in organic synthesis. OH COOH salicylic acid (a) The flowchart below shows some reactions of salicylic acid. (i) In the box below, draw the structure of the organic compound formed by reaction 1. [1] OH COOH excess NaOH(aq) reaction 1 salicylic acid Br2 reaction 2 reaction 3 OH Br COOH OH CH(CH3)2OCR 2014<br />
 (ii) Describe what would be observed during reaction 2.[1] (iii) Write a chemical equation to represent reaction 2. (iv) State the reagents and conditions in reaction 3.[1] (b) Bromine reacts more readily with salicylic acid than with benzene. [1]OCR 2014 (i) Outline the mechanism for the bromination of salicylic acid shown in reaction 2 in the flowchart. A halogen carrier is not required for this reaction. The electrophile is Br2. [4] Turn over<br />
 (ii) Explain why bromine reacts more readily with salicylic acid than with benzene. In your answer, you should use appropriate technical terms, spelled correctly.[3]OCR 2014<br />
 (c) Mesalazine is a drug that can be synthesised from salicylic acid in two steps. OH COOH salicylic acid two-step synthesis OH H2N COOH mesalazine (i) Suggest a two-step synthesis to prepare mesalazine from salicylic acid. For each step state the reagents used,write a chemical equation. (ii) Mesalazine reacts with acids to form salts. Explain how mesalazine is able to react with acids.[1] [4]OCR 2014 Turn over<br />
 (iii) Mesalazine reacts in another two-stage process as shown below. In the boxes, draw the structures of organic compounds A and B. [2] OH NaNO2 and HCl H2N COOH < 10 C mesalazine compound A NaOH(aq) followed by neutralisation compound B OH OH COOH (d) Salicylic acid can be used to form a condensation polymer similar to Terylene. OH COOH salicylic acid (i) Explain what is meant by the term condensation polymer.[1]OCR 2014<br />
 (ii) The repeat unit of Terylene is shown below. C O CH2 CH2 Terylene Draw the skeletal formulae of two monomers that can be used to form Terylene. (iii) Salicylic acid reacts with 3-hydroxypropanoic acid to form a mixture of condensation polymers. To form one polymer, the two monomers react in equal quantities. Draw the repeat unit of this polymer, displaying the link between the monomer units. [2] [1] [Total: 22]OCR 2014 Turn over<br />

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