Making chemistry greener

Brianna Furman '27 works in Professor Isaiah Speight's mechanochemistry lab. Here she is pictured holding a mechanochemical milling jar after a reaction. (Photo by Tim Sofranko)

Industrial chemical synthesis - the reactions that create everything from medicines to soaps to fertilizers - generated huge quantities of solvent waste each year. In the U.S. alone, around 24 billion pounds of solvent waste was generated in 2024, according to an Environmental Protection Agency tracker. Some of these solvents - the liquid medium within which reactions are performed - are costly and pose hazards to the environment and human health.

Green chemistry is a movement that hopes to solve the solvent problem and make chemistry safer, more environmentally friendly and sustainable. Isaiah Speight, William & Mary assistant chemistry professor, recently talked with W&M News about the promise of green chemistry.

Speight studies mechanochemistry - the use of mechanical force to drive chemical reactions. He is one of 11 principal investigators involved in the National Science Foundation Center for the Mechanical Control of Chemistry. A collaboration across 14 institutions, including Texas A&M University, Massachusetts Institute of Technology and Vanderbilt University, this group is focused on establishing a fundamental understanding of mechanochemistry.

Speight has contributed several articles to Chemical & Engineering News on this topic, including "Why green chemistry makes science safer for everyone" and "Greening Chemistry: Time is a terrible reagent to waste."

The Speight group's work is one example of how the W&M community is driving forward sustainability research and working to safeguard the environment. Check out the Year of the Environment webpage to learn more about the university's initiatives.

Q. What is green chemistry?

A. Green chemistry is less a specific technology and more a guiding philosophy. It's a thought process of how to make chemistry environmentally safer and more sustainable, while also improving safety for the user. It considers the entire life cycle - from how materials are sourced to how a product is used and ultimately disposed of - with the goal of protecting everyone who interacts with the chemistry along the way. This holistic approach benefits not just the people doing the work, but the broader scientific and commercial communities.

Q. What sparked the genesis of green chemistry?

A. This mindset began gaining traction throughout the 20th century as chemists became more aware of the health and environmental impacts of their work. Earlier laboratory practices were often unsafe by today's standards - people smoked in labs, mouth-pipetted and handled toxic chemicals with minimal protection. As evidence of harm accumulated, tighter regulations, safer practices and environmental protections followed. Those shifts helped lay the groundwork for what we now call green chemistry.

Q. How is the field of green chemistry developing today?

A. Today's green chemists are focused on continuing to increase safety for people and the environment while also making chemistry more robust and reliable - meaning reactions are faster, safer and produce higher yields with less waste. Techniques like biocatalysis, photocatalysis and mechanochemistry help us do that by using safer solvents, fewer solvents or none at all.

Q. What are solvents and why can they be problematic?

A. Many chemical reactions are performed in solvents - meaning the reactants are dissolved in a liquid that facilitates the reaction. The issue with solvents is twofold. First, common solvents like chloroform and dimethylformamide can pose health risks to lab workers. Second, they make up a large component of chemical waste and can harm the environment.

Think about having a bowl of cereal. You finish the solid cereal, but the milk left in the bowl has served its purpose and gets poured down the drain. In this analogy, the milk is the solvent - it enabled you to eat the cereal efficiently, but once the "main ingredient" is gone, it's treated as waste.

The same thing happens in many chemical reactions. You run a reaction, isolate the product and the solvent that enabled the reaction often has no further use, so it gets discarded.

Q. Tell me more about your specialty: What is mechanochemistry and how does it fit into green chemistry?

Instead of mixing chemicals in a solution to perform reactions, mechanochemistry uses mechanical energy, grinding for example, to make bonds or break them apart. Importantly, mechanochemistry uses little to no solvents, which is making it quite a hot field at the moment. But it's not a new idea. Humanity has been doing mechanical grinding since the dawn of time: Think of grinding herbs to make medicines and spices or crushing berries to make paints for pictograms in caves.

Q. Beyond decreasing solvent use, what are other advantages of mechanochemistry?

A. So disclaimer: Mechanochemistry is not a panacea, but it does allow for some very unique reactivity profiles. For example, this approach can perform some reactions very quickly compared to liquid-based reactions.

If you look at a solution reaction, you're just kind of swirling things around and hoping that they meet. Sometimes you have to wait a long time for this to happen, especially because a lot of reactions are run very dilute for safety reasons. But in a mechanochemical environment, there's nothing else there but the reagents themselves. So the chemical compounds are always going to find each other.

And decreasing or eliminating solvents means that mechanochemistry isn't bound by the rules of solubility. Reagents chemists would normally avoid - because they won't dissolve or there's no solvent that drives the reaction you want - suddenly become usable. It creates this open playground we can explore.

Q. How does your mechanochemistry lab differ from a standard chemistry lab?

A. In a standard chemistry lab, you'll see round-bottom flasks and beakers for mixing solutions. Our lab is fundamentally different; everything we do is a "collision event" or a "grinding event."

We use a very simple setup: hollow stainless-steel cylinders loaded with chemical reagents and a stainless-steel ball. We then apply force by shaking, spinning or vibrating these cylinders.

This movement isn't just a way to mix materials; it is the chemistry itself. The specific motion and applied force guide the reaction, offering a powerful way to control outcomes and explore new chemical transformations that aren't possible in a solution-based environment.

Q. Where do you see the field of green chemistry headed in the next few years?

A. The critical turning point for green chemistry is happening right now, driven by education.

We are training junior scientists to inherently think in an environmentally sustainable way. The future growth of the field lies in equipping the next generation of scientists with the mindset and tools needed to make discoveries in a safer, faster and more conscientious manner.

Q. What's one way your lab is involved in this movement?

A. The National Science Foundation Center for the Mechanical Control of Chemistry is a multi-institution effort to figure out the fundamental "rules" of mechanochemistry - what makes a reaction work when force is applied, how reactions progress and how we can control them. My students and I are involved in this collaboration in a number of ways, from elucidating fundamental reactivity profiles of early stage mechanochemical reactions to designing 3D printed reaction vessels to creating a database of mechanochemical reactions.

Learn more about Speight's work at the Speight Research Group website.

Catherine Tyson, Communications Specialist

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