How do you design a reaction with high atom economy?

To design a reaction with high atom economy, you should aim to minimise waste and maximise the use of all reactants.

Atom economy is a concept in green chemistry that measures the efficiency of a chemical reaction. It is calculated by comparing the total mass of the desired product to the total mass of all products. A reaction with high atom economy is one where the majority of the reactants end up in the desired product, rather than being wasted as by-products.

To design such a reaction, you need to consider several factors. Firstly, you should aim to use reactants that will all contribute to the final product. This means avoiding excess reactants that will not be incorporated into the product and will instead become waste.

Secondly, you should aim to use a reaction pathway that produces few or no by-products. This often involves choosing a direct synthesis route, where the reactants are converted directly into the product, rather than a multi-step process that produces intermediate compounds.

Thirdly, you should consider the conditions under which the reaction takes place. Reactions that require high temperatures, pressures or the use of hazardous solvents are less efficient and less sustainable, so these should be avoided where possible.

Finally, you should consider the use of catalysts. Catalysts can increase the rate of a reaction and help direct it towards the desired product, reducing the amount of waste produced.

In summary, designing a reaction with high atom economy involves careful selection of reactants, reaction pathways and conditions, with the aim of maximising the use of all reactants and minimising waste.