Edexcel Jun 2015 (IAL) Paper 4 Q15

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15 Aldehydes can be synthesised in the laboratory by the reaction of esters with the reagent diisobutylaluminiumhydride (DIBAH), which acts as a source of hydride ions. An example is shown below. (CH2)10 H3C ester Y CH3 DIBAH 78C Yield = 88% H3C C H2 (CH2)10 HO dodecanal (a) Give the systematic name of ester Y. CH3 C H2 (1)(b) DIBAH acts as a source of hydride ions. What type of reagent is DIBAH? (1)(c) Suggest why the reaction is kept at 78C. (1)(d) The overall yield for this process is 88%. Calculate the mass, in g, of dodecanal that would be formed from 5.26 g of the ester Y. [Molar masses / g mol1: ester Y = 228; dodecanal = 184] (3) (Total for Question 15 = 6 marks) *P45075A02128* 21 Turn over<br />

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