atomeconomical

Atomeconomical is an adjective used in discussions of green or sustainable chemistry to describe chemical processes, reactions, or synthetic routes that maximize atom economy. An atomeconomical process aims to convert as many atoms from the starting materials into the desired product as possible, thereby reducing waste and the need for purification or disposal of byproducts.

Atom economy is a theoretical measure defined as the ratio of the molecular weight of the desired product to the sum of the molecular weights of all reactants, multiplied by 100%. A higher atom economy indicates a more atomeconomical route, but this should not be conflated with reaction yield.

The concept is used in planning syntheses and evaluating proposed activities in green chemistry. It helps researchers compare alternative reaction pathways and select conditions, solvents, and catalysts that minimize unused atoms and waste streams. Nevertheless, atom economy is one of several factors shaping a sustainable process; energy use, safety, cost, and scalability also matter.

Examples of high-atom-economy strategies include many carbon–carbon bond-forming cycloadditions and cascade or tandem processes that assemble complex products from simpler building blocks with minimal side products. In practice, achieving very high atom economy can require catalysts, reagents that are matched to the reaction, or a design that avoids stoichiometric auxiliaries.

Limitations include its focus on the stoichiometric balance of atoms rather than energy input or process safety. It also assumes idealized reaction conditions and complete conversion. As a result, the term atomeconomical is best used alongside complementary metrics such as the E-factor and process mass intensity.