Green Chemistry

Water presents significant advantages when used in heterogeneous catalysis. Unlike traditional organic solvents, water is non-toxic, non-flammable, and readily available. Heterogeneous catalysts, which differ in state from the reaction medium, can be performed in water to facilitate various chemical reactions. For instance, micellar catalysis has proven effective for aminations, leveraging recyclable catalysts and aqueous reaction media to achieve high reactions yields of pharmaceutical APIs and complex targets.

The use of polymeric materials from renewable resources has a long history, with naturally occurring polymers being among the first materials used by men. In the 19th century, natural materials, such as casein, natural rubber, and cellulose, were modified to obtain useful polymeric materials. Over the past few decades, the production and application of synthetic polymers have seen an almost exponential increase.

Metal catalysts play a fundamental role in the pursuit of sustainable practices. They can optimize efficiency and minimize waste in chemical reactions that produce sustainable products/processes, helping to reduce harmful substances to the environment and human health, combat climate change, and generate clean energy. The most widely used catalysts are noble metals (e.g., platinum, palladium, and iridium) due to their desirable catalytic properties, such as high stability and temperature tolerance. However, the use of noble metals is hindered by their high cost and limited availability.

Key points

• Biocatalysis refers to the use of natural catalysts, such as protein enzymes, to conduct chemical reactions. 
• These biocatalysts are particularly advantageous in chemical processes because they combine the selectivity of directing groups and the efficiency of catalysts into single reagents. 
• Enzymes can also be combined with other enzymes in one-pot reactions, allowing for complex multi-step syntheses.

An overview of Phase Transfer Catalysis (PTC)