The highest possible value of atom economy is 100%, when all the reactant atoms end up in the desired product. If the atom economy is 50%, for example, then half the reactant atoms end up in the desired product or products. Atom economy:
The Gabriel synthesis of amines is an example of extremely low atom economy, as stochiometric quantities of phthalic acid derivatives are formed. In most cases, the atom economy of the Gabriel
synthesis is <<50%.