WM 5- Synthesis Of Aspirin Flashcards
Define green chemistry
Developing chemical processes and products that are as sustainable and environmentally friendly as possible
What did the old method of manufacturing the drug taxol involve, and how is the new method greener?
OLD method-
- extracting bark from Pacific Yew tree, which is slow growing
- needed vast quantities and killed the tree
NEW method-
- tree cells grown in fermentation vat
- product extracted by recrystallisation
What did the old method of manufacturing the drug atorvastatin involve, and how is the new method greener?
OLD method
- synthesised in a reaction involving toxic solvents
NEW method
- synthesised using an enzyme that catalysed reaction under water so less harmful solvents
What did the old method of manufacturing the drug ibuprofen involve, and how is the new method greener?
OLD method
- 12 step process with 40% atom economy
NEW method
- 4 step process with 77% atom economy
What are the negative effects of using greener methods of carrying out chemical process?
- if you use lower temp, longer to reach eqbm, higher costs as plant is open longer
- different/greener reagents maybe more costly
- there may be safety issues with new reagents
- maybe an affect on overall yield
What is used instead of salicylic acid to produce aspirin, which is more widely available and has 100% atom economy?
Phenol
What is added to phenol to make salicylic acid?
CO2
When a drug is produced why is the product not 100% pure?
- contains unreacted reactants
- contains solvents
- minor products
- catalysts
Give method of recrystallisation
- Solvent is used which is soluble in HOT temp but insoluble in COLD
- Drug is dissolved in min. amount of HOT solvent
- Mixture is filtered, insoluble impurities are removed
- Mixture is submerged in ice bath, and substance will crystallise as insoluble in COLD
- Filter, substance will be filtered out, collect and dry in oven
