In 1970, the first nationwide Earth Day was celebrated in the U.S. as an environmental awareness event celebrated by millions. Green chemistry promotes the careful design of chemicals manufacturing processes to reduce the use of toxic components and minimize waste and energy use on Earth Day and everyday.
When ibuprofen was first manufactured in the 1960s, it generated more waste than drug. Chemists were making ibuprofen by adding an excess of aluminum trichloride to isobutyl-benzene and pushing through a six-step reaction with solvents and separation agents. Although the method certainly turned out the drug, it was highly inefficient and produced unwanted by-products at each step of the way: an annual production of 30 million pounds of ibuprofen generated 45 million pounds of waste, mostly tossed for scrap.
But in the early 1990s ibuprofen got a makeover. Using catalysts rather than excess reagents to drive the reactions, chemists halved the number of stages in the ibuprofen manufacturing process and eliminated carbon tetrachloride, a toxic solvent, from the process. In the new process, atom economy—the percentage of raw materials and reagents used in the synthesis that ends up in the final product—hovered between 80% and 99%. Those materials and reagents that didn’t end up in the final product, such as acetic acid, could be reclaimed or recycled. The revamped reaction was not only good for business (in that it reduced clean-up costs and minimized the consumption of raw materials), it was good for the environment.
A new type of chemistry—green chemistry—is taking hold of academia, industry, and government. Green chemistry rethinks the design of chemical processes and offers environmental benefits by reducing waste, eliminating expensive chemical treatments, and reducing the use of energy and resources.
Visit Chemical Heritage Magazine to learn more about the origins of green chemistry.
Excerpted with permission, Chemical Heritage Foundation