Green chemistry pioneers aim to change world

The earth is currently plagued by a number of very vexing molecules: carbon dioxide and methane in the atmosphere, plastic polymers in the oceans, and hydrocarbons in our energy systems, to name a few.

Is there a unifying solution to all of this? Well, no, but for Dr John Warner and Professor Paul Anastas, pioneers of “green chemistry”, there is a way to make the right molecules in the first place.

So profound has this simple proposition been that it’s taken them from US universities to the White House, and from start-up companies to not-for-profits that are changing entire curricula. They were popular guests at the First Australian Conference on Green and Sustainable Chemistry and Engineering, held in Cairns.

Warner and Anastas have spent much of the past three decades encouraging chemists to design products that avoid negative effects on the environment.

“Sometimes people think of green chemistry as some hazy path – you know, we’re going to put on slippers and robes, get clay pipes and smoke pot,” Warner told Cosmos in Cairns. “In fact, it’s quite the opposite. You drop nothing. You add green chemistry to what normal, ‘traditional’ chemists do.”

In 1998, Anastas and Warner published a book outlining 12 principles for making chemistry greener.

These principles range from choosing appropriate ingredients, all the way to waste prevention and degradation at the end of a material’s job.

One is energy efficiency – which for chemists, means things like choosing reactions that can be done at room temperature rather than under high heat.

Another is catalysis: using a small material that provokes a reaction, without getting consumed itself, is much less wasteful than using large amounts of another substance to react with the material you’re working with.

Green chemists, by Anastas and Warner’s definition, consider the 12 principles, before beginning to make their molecules.

This doesn’t mean that every principle is adhered to perfectly in every single molecule a chemist makes.

“In all the work that I have done, I have never simultaneously addressed all 12 principles,” says Warner.

But they must be considered first.

“That means that you are consciously building them into a deliberative process, because you value those things, and you want to ensure that you make the best efforts to achieve them,” says Anastas.

“The process of considering them is not weak – it is very, very powerful.”

Chemists are used to making products that do one job as well as possible – like making the most efficient drug to treat a medical condition, for instance. It’s a big mental shift to get them considering 12 other factors, like biodegradability and hazardous solvents, as well.

But it’s not necessarily less productive to do it this way.

“What happens now in industry is something really cool gets invented, and everyone gets excited. Next thing, you’ve got business people, you’ve got sales, and they start spending hundreds of thousands, maybe millions, of dollars,” explains Warner.

“About a year, or a year and a half in, someone says ‘Okay, let’s go to manufacturing – wait, we can’t use that solvent. We can’t use that reagent’.”

Because the chemists designing these products in the first place aren’t thinking about the hazards or the effects of their designs, they fail to anticipate when those hazards might be too high to make their work viable commercially.

“Not only is there a loss of productivity, there’s this psychological nastiness going on in that company,” says Warner.

“Had that first chemist understood green chemistry – not always, things are still going to slip through the cracks – but there is a much better chance that by understanding toxicity, and environmental impact, they will avoid those profound mistakes that become very costly to industry.”

Warner, who has been granted over 300 patents, has the evidence to show that green chemistry can be the smartest industrial bet. His inventions include hair colour that restores grey hair back to its original black or brown, an asphalt rejuvenator that allows old bitumen to be re-used, and pharmaceutical therapies for the nervous system disease, ALS.

One of Anastas’ many projects, meanwhile, is the Molecular Design Research Network, which is finding the qualities that make a molecule toxic – in the same way that chemists can predict what could make a molecule dissolve in water, or melt at a low temperature.

“We’ve been able to design molecules that have all kinds of functionality, but we’re not so good at designing things to be nontoxic,” he says.

“So how do we go about reducing toxicity by design? A huge advantage that we have is there’s a better part of a century devoted to pharmaceutical manufacturing, and pharmaceutical discovery.

“All of these lessons that we’ve learned about how to make a molecule that can get into the body, that can cross the right membranes, that can find the right receptor in order to cause a biological effect – you now turn those lessons on their head, and say you want a molecule that doesn’t get into your body, that doesn’t bind to another receptor, that doesn’t cause a biological effect.”

After a quarter of a century in the mainstream, what’s next for green chemistry? Warner is focused on education, particularly through the organisation Beyond Benign, which he founded with his wife Dr Amy Cannon.

“If we change education, we get all the problems, because there’s enough diversity of people that can go out there and start solving problems,” he says.

Anastas has a few more specific pointers – using waste, and particularly CO₂, as chemical feedstocks, and using photons and electrons to provoke reactions rather than dangerous substances like chlorine and cyanide.

But he is also still looking for widespread change, as is evident from his latest book, First Do No Harm.

“When I say ‘what’s next for green chemistry’, it’s really what’s next for chemistry, because all chemistry needs to be green.”

Ellen Phiddian’s airfare to Cairns was paid by the Royal Australian Chemical Institute, which managed the First Australian Conference on Green and Sustainable Chemistry and Engineering.