Green Chemistry

With the world becoming more aware of the damage caused by certain chemicals and the over use of energy resources the scientific community has now begun to act more responsibly. New and existing processes are now scrutinised more closely in terms of their environmental impact. Paul Anastas, an organic chemist came up with 12 main principles for chemical processes to try to adhere to.

They are:-

  1. Prevention
  2. Atom economy
  3. Less hazardous chemical synthesis
  4. Designing safer chemicals
  5. Safer solvents and auxiliaries
  6. Design for energy efficiency
  7. Use of renewable feedstocks
  8. Reduce derivatives
  9. Catalysis
  10. Design for degradation
  11. Real-time analysis for pollution prevention
  12. Inherently safer chemistry for accident prevention

In simple terms this means that chemists need to ask themselves questions such as;

  • Can this process be carried out using lower temperatures/pressures in order to save energy?
  • Are there renewable chemicals that can be used as reactants such as plant/bacteria derived substances?
  • Are the reactants or products harmful and how can this be minimised?
  • Can the product be made in such a way that it can easily degrade after use?
  • Are there uses for the by-products of the process rather than throwing them away?
  • Are there alternative methods for the production of existing chemicals to improve efficiency or atom economy?

An example of where these principles have been put into use is the manufacture of the common painkiller Ibuprofen. When this drug was originally synthesised the process took six individual steps and had an atom economy of 40% (the amount of atoms in the useful product made compared to the number of atoms used in the reactants). However the company BHC developed an alternative method which only involved 3 steps, involving catalysts (which lowered energy costs), started with fewer chemicals (reducing material cost) and having an atom economy of 99% (virtually no waste products to dispose of). The small amount of waste that was produced could be used in other chemical processes. Therefore Chemists are improving quality of life, making a profit and saving the planet!