Spin Doctors: Reducing Environmental Burdens Through Better Chemistry
EPA scientists and partners develop new spinning methods to “green” chemical production.
EPA chemist Dr. Michael Gonzalez describes standard chemical batch manufacturing processes as being a bit like boiling potatoes in a big pot. While some potatoes are cooked, others are still underdone, requiring the cook to leave them boiling longer. It’s a hard balance. By the time the undercooked ones are ready, others that have not been removed are ruined. The same inefficient scenario often holds true in chemical manufacturing processes.
Gonzalez and his collaborative research partners are working to change that and to help protect human health and the environment at the same time. Their innovative research, performed in a “spinning tube-in-tube” reactor, allows for each chemical to be “cooked” and removed after it is done, without affecting the rest of the batch.
Gonzalez, from the Sustainable Technology Division of an EPA research lab in Cincinnati, OH, embraces the principles of green chemistry to advance the development of cleaner synthesis techniques for commodity and specialty chemicals. He and his partners are exploring the development of innovative, benign substitutes—such as the spinning tube technology—for harsh chemical catalysts or solvents.
Catalysts are substances that speed up chemical reactions without affecting the chemicals themselves. Separate chemical catalysts or toxic solvents are widely used during conventional chemical manufacturing efforts. They become hazardous waste at the end of the process.
The increased mixing action within the spinning tube-in-tube reactor, or STT®, promotes or accelerates the desired chemical reaction, while minimizing or eliminating the need for a catalyst or solvent(s).
The STT® reactor has been successfully demonstrated and used within EPA laboratories and has now been licensed by a couple of companies that are looking to build commercial-scale operations for the production of their consumer products.
Through these industry partnerships, EPA scientists and engineers are facilitating the development and wider adoption of green chemical manufacturing approaches that can produce thousands of different chemicals. The methods need no chemical inputs other than the reactants and therefore greatly reduce the time, costs, and energy associated with standard chemical production processes. They also lower safety risks to workers. Reaction times within the STT® reactor are faster, enabling one reactor to produce from two to 12 tons of product per year while having the physical footprint of a six-foot table.
According to Gonzalez, the process has potential applications in the pharmaceutical, industrial chemical, food additive, and fragrance sectors. Application in these industries “offers the maximum opportunity to minimize risks” by applying the principles of green chemistry (such as substituting increased mixing for toxic solvents) and green engineering, he explains. Green engineering comes into play because the physical size of a plant needed for spinning tube reactors is orders of magnitude smaller than that needed for conventional chemical manufacturing with large, room-sized reactor vessels, separation towers, filtering systems, and pipeline networks.
EPA has been collaborating with the Four Rivers Energy Company to co-develop and advance the spinning tube-in-tube technology. “By partnering with Four Rivers and with the chemical industry, we’ve been able to tackle real-life challenges, apply sustainable solutions to these challenges, and work with more than 20 companies to get these technologies out into the marketplace,” Gonzalez says.
Gonzalez often speaks to student groups about green chemistry and green engineering as emerging ways to make chemicals. According to Gonzalez, using sustainable principles is “pollution prevention at the molecular level.” Gonzalez also says that he has found other audiences eager to learn more. “This research is an opportunity to show new ways of doing things to colleagues, industry scientists, and society so they can educate the next generation of chemists and consumers as we head down the path to sustainability.”