Procedure Place dicyclopentadiene (30 cm3) and a few anti-bumping granules in a 100 cm3 roundbottom flask and set up the apparatus for distillation, with the receiving flask in an ice-bath. Raise the temperature of the heating mantle slowly until cyclopentadiene (monomer) collects slowly (dropwise) in the receiving flask. The distillation temperature should not exceed 65 oC. Collect 3-5 cm3 of the distillate and keep it in the ice-bath until use. Allow the apparatus to cool and, when safe to handle, return the unused dicyclopentadiene to the bottle provided. Rinse the apparatus with acetone and return it to the box – it will be needed later on in the practical by another group. Dissolve maleic anhydride (1.0 g) in toluene (15 cm3). Cool the solution in an ice bath and, when cold, add 1.0 g of cyclopentadiene (monomer). Swirl the flask and leave to stand in the ice-bath; record the time taken for crystals to appear. Filter the cyclopentadiene-maleic anhydride using a Buchner filtration apparatus, record the yield and obtain an IR spectrum. An NMR spectrum of the product will be posted on the weblearn site: interpret this for inclusion in your portfolio for assessment in Semester 2. Return the unused cyclopentadiene (monomer) to the bottle used to collect dicyclopentadiene (dry the outside of the round bottom flask before pouring it back in – it is important that the recovered dicyclopentadiene/cyclopentadiene is not contaminated with water). CH5008 Experiment 3 – Diels-Alder reaction of maleic anhydride with cyclopentadiene mark guide Introduction • Brief description of experiment – Diels-Alder reaction (what type of reaction/number of electrons moving) • Mechanism to explain reaction 15 marks Aims • 1 or 2 sentences of the aim written in students own words (think about all steps being done, not just the final cycloaddition reaction) 5 markMethod • Description of experiment in own words (must use format given in guidelines) o must be in the 3rd person o substrate (amount in brackets after) o must be written in paragraph formato observations o use of suitable amount of decimal places for amounts 30 marks Results and discussion • Scheme of reaction (this may have been included earlier) • % yield – with calculations (maybe in table) • Discussion of yield and cracking temperature (comparison to literature) • Discussion of IR and NMR analysis 40 marks
Conclusion • Outcome of the experiment – were the aims met? can results be related to the discussion 5 marksReferences • Peer reviewed articles • Correct/consistent style
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