OCR A Jan 2011 Paper 2 Q2

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6 2 Butyl ethanoate is an ester used as a flavouring. This ester can be synthesised from butan-1-ol by two different processes. Process 1 is a one-step process that involves a reversible reaction. CH3CH2CH2CH2OH + CH3COOH The percentage yield for process 1 is 67.1%. The atom economy for process 1 is 86.6%. CH3COOCH2CH2CH2CH3 + H2O Process 2 is a two-step process. CH3COOH + SOCl2 CH3COCl + SO2 + HCl CH3CH2CH2CH2OH + CH3COCl CH3COOCH2CH2CH2CH3 + HCl The overall percentage yield for process 2 is 93.3%. The overall atom economy for process 2 is 45.8%. (a) Draw the skeletal formula for the ester butyl ethanoate. (b) Show that the atom economy for process 1 is 86.6%.OCR 2011 [1] [2]<br />
 (c) A research chemist investigates process 1. She finds that 6.25 g of butan-1-ol forms 6.57 g of butyl ethanoate. (i) Suggest the conditions needed for this reaction.[2] (ii) Show that the percentage yield of process 1 is 67.1%. [2] (d) Explain why process 2 has a high percentage yield but a low atom economy.[2] (e) Suggest two reasons why butyl ethanoate is manufactured by process 1 rather than by process 2.[2]OCR 2011 [Total: 11] Turn over<br />

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