Ways to Modify Processes
Through simple modification of syntheses, one can reduce, or eliminate toxic starting materials, by-products and waste and yet arrive at the same product.
Alternative feedstocks or starting materials can be used, as can alternative reagents. to find the best reagent, a balance must be achieved between availability, efficiency and effect.
Changing the solvent is another major way to modify a process. Research has also been conducted into the use of solventless systems. On a small scale, domestic microwave ovens have been used for the solventless preparation of ionic liquids. This concept has been scaled up for use in large applicators for catalytic organic reactions. Microwave enhanced synthetic reactions are more rapid, safe and eco-friendly than conventional methods and will benefit the pharmaceutical industry especially.
Solvents which are being looked at on a large scale are water. supercritical fluids and ionic liquids. The use of water is an active area of research. It is considered safe, inexpensive and environmentally benign. Some reactions, such as conventional organometallic reactions are water sensitive and are therefore more of a challenge. The superheating of water has also proven to be successful method for a variety of synthetic organic reactions. These high temperature processes can reduce the amount of acid or base required for a reaction and so reduce waste. Water can act as a solvent or medium, and at times a catalyst.
Alternative products are a possibility as long as a particular function can be achieved.
Catalysts are a major area of interest. Finding new or alternative, effective catalysts is a huge area of research. Advancing the level of efficiency of reactions can increase environmental benefits. The use of a new catalyst can remove the need for large quantities of reagents that would otherwise have been needed and would have ultimately contributed to the waste stream. For example, OsO4 is extremely toxic, new methods have been developed so that it is only required in catalytic amounts.