Atom Economy (Atom Utilisation)
- One of the key concepts of green chemistry is to reduce waste.
- Waste can be reduced by designing chemical processes to incorporate the maximum amount of all the raw materials into the final product.
- The atom economy (atom utilisation) of a chemical reaction is a measure of the percentage of the starting materials that actually end up in useful products*.
- For the general chemical reaction:
reactants desired product + waste products
The atom economy can be calculated in either of two ways:*
(I) % Atom economy = mass of desired product
mass of desired product + mass of waste products
× 100 (II) % Atom economy = mass of desired product
total mass of all reactants
Equation (I) is identical to equation (II) because by the Law of Mass Conservation:
total mass of all reactants = mass of desired product + mass of waste products
- The greater the value of the %atom economy, the less the amount of waste product produced.