Preparation of aspirin 0.0 / 5 ? ChemistryReactionsFunctional GroupsA2/A-levelAQA Created by: jamey_brewsterCreated on: 01-05-19 18:50 Why is ethanoic anhydride used instead of acyl chloride? Cheaper, less corrosive, less vulnerable to hydrolysis and less dangerous to use (ethanoic acid is the by-product instead of HCL.) 1 of 7 Why is the mixture cooled when the reaction has ended? So that the aspirin crystallises. 2 of 7 Why is the reaction carried out in reflux apparatus? So that any reactants that vaporise will condense back into the reaction flask - increases yield. 3 of 7 Why are naked flames avoided during recrystallisation? As ethanol is highly flammable. 4 of 7 Why is the hot solution containing aspirin dissolved in ethanol poured through a filter funnel? Why is this done hot? To remove insoluble impurities. Filtered hot to prevent crystals reforming during filtration. 5 of 7 Why will soluble impurities remain in solution during the final filtration (vacuum filtration)? They are present in small quantities so the solution is not saturated. 6 of 7 Why is the mixture cooled in an ice bath before the vacuum filtration? Increases the yield of crystals. 7 of 7
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