OCR A Jan 2012 Paper 2 Q2

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2 Ethanoic acid, CH3COOH, is used to make esters. Some information about two of the processes used to make ethanoic acid is given below. Process 1 This is a one-step process that involves the reaction of methanol with carbon monoxide. CH3OH + CO CH3COOH The conditions used are 180 C and 30 atmospheres pressure. A rhodium/iodine catalyst is used. The percentage yield for this process is 99%. Process 2 This involves the oxidation of naphtha, a fraction obtained from crude oil. Liquid naphtha is oxidised using air at a temperature of 180 C and 50 atmospheres pressure. No catalyst is needed. A large variety of other products are also formed in this oxidation. (a) Suggest three advantages of making ethanoic acid using Process 1 rather than Process 2.[3]OCR 2012 Turn over<br />
 (b) The other products formed in Process 2 are carboxylic acids, aldehydes and ketones. A research chemist investigates some of these other products of Process 2. (i) The research chemist isolates product, J. The infrared spectrum of J is shown below. 100 transmittance (%) 50 0 4000 3000 2000 wavenumber / cm1 1500 1000 500 The chemist also finds that 0.172 g of a pure sample of J contains 2.00103 mol of J. Suggest, with reasons, one possible structure for J. In your answer you should link the evidence with your explanation.[5]OCR 2012<br />
 (ii) The chemist isolates another product, the carboxylic acid, K. K has the molecular formula C4H8O2. Suggest a possible structure and name for K. structure name[2] (c) Ethanoic acid is used in the manufacture of the ester, propyl ethanoate. Describe how ethanoic acid is converted into propyl ethanoate. Include an equation in your answer.[4] [Total: 14]OCR 2012 Turn over<br />

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