DefinitionGreen chemistry is “the design of chemical products and processesthat reduce or eliminate the use andgeneration of hazardous substances”.
12 Principles of Green Chemistry ...... ….. 7. Maximize atom economy What’s atom economy ?
Atom economy describes the conversionefficiency of a chemical process in terms of allatoms involved. In an ideal chemical processthe amount of starting materials or reactantsequals the amount of all products generatedand no atom is wasted. Recent developmentslike the advent of Green chemistry and highraw material (oil) prices increasingly demandhigh atom economy.
It is possible to calculate how successful one of these processes is by using the idea of yield Mass of product actually made% Yield = _______________________ X 100 Maximum mass of product that could be made(theoretical yield)
If 50 kg calcium carbonate is used and 21 kgcalcium oxide is made, what is the percentage yield of the reaction? theoretictal yield = 28kg calcium oxide 21kg% yield = _____________ x 100 = 75% 28 kg
A reaction can have a high percentageyield but also make a lot of waste product.This kind of reaction has a low atom economy.