Atom Economy Lecture Notes

These flashcards review key points on atom economy, its calculation, significance, industrial relevance, and strategies for improvement.

What is atom economy?

A measure of how efficiently atoms in the reactants are incorporated into the desired product of a chemical reaction.

Why is atom economy important in green chemistry?

It indicates sustainability by showing how much waste is produced; higher atom economy means less waste and better resource efficiency.

What is the formula for calculating atom economy?

Atom economy = (Molar mass of desired product ÷ Sum of molar masses of all reactants) × 100%.

What does a high atom economy (close to 100%) tell you about a reaction?

Most reactant atoms end up in the desired product, indicating minimal waste and high efficiency.

What does a low atom economy signal about a chemical process?

A large fraction of reactant atoms become unwanted by-products, lowering efficiency and increasing environmental impact.

How does atom economy differ from percentage yield?

Atom economy is theoretical and measures atom use efficiency, while percentage yield is experimental and measures actual product obtained.

Why do industries favor processes with higher atom economy?

They reduce waste and disposal costs, use resources efficiently, are often safer and cheaper, and align with green chemistry principles.

Give an example of a reaction with 100% atom economy.

Addition reactions such as ethene + Br₂ → 1,2-dibromoethane, where all atoms in reactants appear in the product.

Provide an example of a reaction that typically shows low atom economy.

Substitution reactions that release a small by-product, e.g., haloalkane synthesis producing HCl.

List two strategies chemists use to improve atom economy.

Favoring addition reactions over substitution/elimination and designing selective catalysts (others include using renewable feedstocks and minimizing by-products).