Inherent Atom Economy


Organic reactions are classified as additions, substitutions and so on. Each type by its nature has a higher or lower atom economy.

Reaction Type

Description

Atom Economy

Example

Addition

Different molecules join together to make a new substance

100% as all reactant atoms end up in the product

Manufacture of ethanol from ethene. Show me

Click for more on the manufacture of ethanol

Condensation

Two molecules join, with the production of a small molecule like water or ammonia

Always a little less than 100% as small molecules are produced, which are usually waste.

Manufacture of nylon 6,6 from an acid and an amine Show me

Click for more on the manufacture of nylon

Elimination

A group of atoms is removed from a molecule, usually leaving a double or triple bond

Generally poor because an additional product is always formed

Making phenylethene for poly(phenylethene) production Show me

Rearrangement

Atoms are rearranged to create a different substance with the same empirical formula

100% as the same atoms are present in the product as in the reactant

Processing of fats to raise their melting point.  Show me

Substitution

A group of atoms on a molecule is replaced by a different group

The group replaced creates a product too, but as this may vary considerably, substitutions can be from fairly good to very poor


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