Without realizing it, artificial chemicals have become the backbone of modern society. From plastic to cosmetics to pharmaceutical industries, chemical-producing sectors are making significant impacts on the current world, culturally and physically. However, with the boom of these industries, the daily manufacturing processes and the waste produced from them have also caused major pollution and resource depletion issues.
Around the 1990s, scientists and industries worldwide started implementing efforts to advance research and develop strategies to address these problems, leading to the first wave of green chemistry. Green chemistry, also known as sustainable chemistry, is an approach focusing on designing and implementing chemical processes that minimize the use and generation of hazardous substances. In the United States, the Environmental Protection Agency (EPA) played an integral role in promoting green chemistry in its early days, by introducing funding and pollution prevention programs. The passing of the Pollution Prevention Act in 1990 boosted the growth of green chemistry, as it declared the need to lower pollution by improving the designs of products instead of their disposal. To this day, the EPA awards multiple “Green Chemistry Challenge” winners yearly to incentivize innovation for “greener” chemical processes.
Two pioneer chemists in the field, Paul Anastas and John Warner co-authored the book “Green Chemistry: Theory and Practice” and listed 12 principles of green chemistry. This book is considered the foundation of green chemistry and is still highly relevant to current-day chemical practices.
E-factor was also proposed during this wave of green chemistry. It is defined as the ratio between the total waste produced from a process and the total product produced. Hence, the higher the waste-to-product ratio, the less efficient and “green” the process is. The pharmaceutical industry is known to have the highest E-factor, reaching over 100, compared to oil refining, with the lowest E-factor of less than 0.1. Needless to say, the pharmaceutical industry would greatly benefit from the promotion of green chemistry.
Some pharmaceutical companies have been putting green chemistry into action. In 2002, Pfizer was one of the “Green Chemistry Challenge” winners for its alternative manufacturing process for Sertraline hydrochloride, the active ingredient in Zoloft. This drug is one of the most commonly prescribed anti-depression medications in the US, with over 38 million prescriptions. Merck and Codexis have also innovated the production of one of their drugs, specifically Sitagliptin phosphate, which is the active ingredient in Januvia, a leading drug for type 2 diabetes. Compared to the 1st generation process, the 2nd generation manufacturing workflow reduced waste by five times, estimated to translate to at least 150 million kg of waste reduction over the lifetime of the drug. Merck recently has also developed a “greener” way to produce Molnupiravir, an anti-viral medication for COVID-19, shortening the manufacturing steps, cutting liquid waste, and increasing the yield by more than 1.5 fold.
According to the EPA, as of 2022, the 133 technologies that the agency has awarded for the “Green Chemistry Challenge” have eliminated 830 million pounds of hazardous chemicals and solvents each year (enough to fill a train nearly 47 miles long), saved 21 billion gallons of water each year (equivalent to the amount used by 980,000 people annually, and eliminated 7.8 billion pounds of CO2 equivalent emission to air (equivalent to getting 770,000 automobiles off the roads).
Green chemistry strives to lower the carbon footprint and hazardous by-products of industrial chemical processes without compromising productivity by reducing waste at the source rather than at the disposal. Adopting green chemistry is beneficial from a business standpoint where products can be created with higher efficiency, or lower costs. More importantly, it directly reduces hazardous chemicals released into the environment, creating a cleaner environment for everyone.
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