Module 6

Module 6—Petrochemicals

Atom Economy—One Way to Green Chemical Processes

 

A chemical process’ atom economy is important when trying to green the chemical industry. Atom economy is a percentage of the molecular mass of the product and the reactants used in creating the product. The equation to calculate atom economy is as follows:

 

     

 

In the calculation for atom economy, the reaction’s waste or by-products are not directly counted, but are significant. What is the waste product of an esterification reaction? How does the molecular mass of the waste product of an esterification compare to the molecular mass of other organic reactions; for example, a substitution reaction? Does the difference in the molecular mass of the by-products of these two reactions result in a significant difference in the atom economy when these two types of reactions are compared?

 

Consider the following worked example that calculates the atom economy for the production of methyl salicylate.

 

Self-Check

 

SC 3. Calculate the atom economy for the esters made using the alcohols and carboxylic acids shown in the following table:

 

Reaction	Alcohol	Carboxylic Acid	Ester
1	ethanol	ethanoic acid	ethyl ethanoate
2	propan-1-ol	methanoic acid	propyl methanoate

 

 

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