The Importance of Green Chemistry in Process Research & Development
Green chemistry or sustainable chemistry is defined by the Environmental Protection Agency as “the design of chemical products that reduce or eliminate the use of hazardous substances”. In recent years there has been a greater societal expectation that chemists and chemical engineers should produce greener and more sustainable chemical processes and it is likely that this trend will continue to grow over the next few decades. This review gives information on solvents and solvent selection, basic environmental metrics collection and three industrial case histories. All three case histories involve enzymatic chemistry. Pregabalin (Lyrica®) is produced using a lipase-based resolution and is extremely unusual in that all four manufacturing steps to make pregabalin are performed in water. Sitagliptin (Januvia®) uses a transaminase in the final chemical step. Finally, a rosuvastatin (Crestor®) intermediate is produced using a deoxyribose aldolase (DERA) enzyme in which two carbon–carbon bonds and two chiral centres are formed in the same process step. It is hoped that the case histories presented in this chapter will inspire process chemists to target even more sustainable chemical processes.