Atom economy definition

Because RME accounts for the mass of all reactants, that is, the actual stoichiometric quantities used, and therefore includes yield and atom economy, this combined metric is probably one of the most helpful metrics for chemists to focus attention on how far from green their current processes actually is. However, like many green chemistry metrics, it does take a little bit of thought to calculate in practice, as one has to work to strict definitions of what to include and what to exclude [46] ... 

At the foundation of the principles of Green Chemistry is that of Atom Economy. This concept as elucidated and demonstrated by Trost (70) couples the most important elements of the idea of environmentally benign synthesis and the definition of synthetic elegance to provide a framework for how synthetic design should be guided. The economical use of atoms in the construction of a synthetic... 

Highlight 2.1 Definition and Calculations Dealing with the Application of Atom Economy... 

Recall from Chapter 2 the definition of atom economy, the ratio of the mass of the species in the desired product relative to the mass of all of the reactants. In all of these reactions the atoms present in the reactants are also present in the products. In this case it is implied that these reactions are 100% atom economical. Remember from Chapter 2 that atom economy is a mass utilization number only it does not take into account the energy usage, the toxicity of the products, or whether the feedstocks are derived from renewable materials. 

Hydrogen is the most abundant element in the universe. Over 90% of all the atoms, and thus about three quarters of the mass of the universe, is hydrogen. This is one very simple reason why the planet is definitely going into a hydrogen economy. 

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