Catalysts and Catalysis in Green Chemistry

The main components of a chemical process can be divided into the categories of catalysts, media, feedstocks, and reagents, all of which are important in the practice of green chemistry. Catalysts and catalysis are addressed in this section, and the other aspects of chemical production are addressed in Section 14.12. 

An ideal green chemical reaction occurs with 100% atom efficiency using only reactants and no other reagents under mild conditions with only moderate input of thermal energy and without any catalysts. Unfortunately, few chemical processes meet these criteria. 

An important area of endeavor in the development of improved catalysts with respect to green chemistry is selectivity enhancement. Basically, this means developing a catalyst that is very selective in what it does, ideally making the right product and nothing else. A highly selective catalyst increases the percentage utilization of raw material (increased percent yield) and decreases the amount of waste by-products from undesired side reactions (smaller E factor). 

Another important attribute of a good catalyst is related to the basic way in which a catalyst works, which is by lowering the activation energy that is required to make a reaction proceed at a significant rate. As a consequence, catalysts lower the total amount of energy that must be put into 

As a second step in the process, the hydrogen peroxide is reacted with propylene to produce propylene oxide with water as the only by-product  

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