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Booklet for unit 28 M3 D3. Organic synthesis maps. Main reactions in organic chemistry:. If you are aiming for M3…. You need to be able to plan a synthesis route and draw up a synthesis map EXAMPLE:
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Booklet for unit 28 M3 D3 Organic synthesis maps
If you are aiming for M3….. • You need to be able to plan a synthesis route and draw up a synthesis map EXAMPLE: Plan a synthesis route with Ethene as your starting molecule and Ethanal as your target molecule Ethene Ethanol Ethanal
If you are aiming for D3…….. • You need state the reaction conditions for each reaction in your synthesis map. • You also need to make a comment likely yield of the final product (the target molecule)
Things can affect the yield of final product • Number of steps/reactions involved. More steps increase sources of errors • Some reactions involve very similar reaction conditions to other reactions. If you don’t use exact reaction conditions then you could end up making a different product • If a product is soluble in water/difficult to separate from other chemicals that you don’t need then this could affect purity as there are contaminants. If you cannot remove all of the product so that it can be used for the next step then there will be less product available to be used for the next step- this will decrease the yield of the target molecule.
If you are aiming for D3….. EXAMPLE: Plan a synthesis route with Ethene as your starting molecule and Ethanal as your target molecule. Heat with conc. H2SO4 Ethanol Ethene Add ethanol to acidified dichromate (VI) and distil Ethanal
In the step of changing ethanol to ethanal, there is a risk of ethanoic acid being made instead if excess acidified dichromate (VI) is used and if the reaction is refluxed instead of distilled. • There are two steps in the synthesis map which means that there are more sources of errors. • Purity may not be high as there may be a mixture of ethanal (the target molecule) and ethanoic acid. Also ethanol is soluble in water so we may not be able to distil off all of the ethanol which means there will be less ethanol to make ethanal which will decrease the yield of the target molecule.
TASK: Plan a synthesis route involving two or more steps between the starting and target molecules listed below. For M3: Draw up a synthesis map for your answer.For D3: Add details on reaction conditions to your synthesis map and comment on likely yield of final product. • 1. Starting molecule: Propanal • Target molecule: Propene • Starting molecule: Ethene • Target molecule: Ethyl ethanoate • 3. Starting molecule: Propanoic acid • Target molecule: Bromopropane
4. Starting molecule: Butanal • Target molecule: Butyl amine • 5. Starting molecule: Bromo ethane • Target molecule: Ethanoic acid • 6. Starting molecule: Propanone • Target molecule: Propyl amine • Starting molecule: Ethyl ethanoate • Target molecule: Ethene • 8. Starting molecule: Ethyl ethanoate • Target molecule: Chloroethane