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Green Chemistry

Editorial: The challenge of going green

by Michael McCoy
July 16, 2023 | A version of this story appeared in Volume 101, Issue 23


In 2019, I wrote a story about efforts by a start-up company and its corporate partners to launch a new solvent they called Cyrene. I was reminded of that article while reading Leigh Krietsch Boerner’s cover story this week about efforts to expand the use of water as a solvent for organic chemistry reactions (see page 20).

The structure of Cyrene.

As Boerner reports, dissolving compounds in a solution is the best way to get them to react, and organic molecules tend to dissolve in organic solvents. The trouble is that many organic solvents are safety or health hazards. They are typically disposed of by incineration, a process that creates greenhouse gases. Chemists would like nontoxic, renewable solvents, and it is in part the dearth of such solvents that causes them to turn to water.

That’s where Cyrene is supposed to come in. Its chemical name is dihydrolevoglucosenone; it’s made by hydrogenating levoglucosenone, a molecule that is derived from cellulose waste. But as is almost always the case for new chemicals and materials being developed by new companies, the road to market has been long.

Cyrene’s origins go back over 15 years, to when the paper industry was confronting declining demand. An industry executive, Tony Duncan, identified levoglucosenone as a promising cellulose-derived molecule. He turned to James Clark, a University of York professor, who came up with the idea of hydrogenating it to create a solvent. The two figured it could replace nitrogen-containing dipolar aprotic solvents like N-methyl-2-pyrrolidone and dimethylformamide. To commercialize the product, Duncan helped form an Australian firm, Circa Group, in 2006 and became its CEO.

Circa is alive and well today, but large quantities of Cyrene cannot yet be found.

Circa and its solvent got a big vote of confidence in early 2021, when the company succeeded in raising about $60 million on the Euronext Growth Oslo stock exchange. Circa is now based in Norway.

The firm has since put some of the money into building a facility in northern France with the capacity to make 1,000 metric tons (t) per year of the solvent from sawdust and wood waste. When the plant was announced in 2020 it was expected to open in September 2023 at a cost of $25 million—half of that paid by the European Union’s Horizon 2020 research and innovation program. The French government is contributing as well.

But these days, the target for opening the plant is late 2024. Moreover, in Circa’s first-quarter financial report, published in May, the firm disclosed that “inflationary pressure across the project” is increasing costs and that it will need to raise more money to complete it.

Some investors are losing faith. Two years ago, Circa’s shares traded for about 16 euros ($18 today). They are around 4 euros now. And output from the company’s pilot facility in Australia is paltry: 588 kg in April.

I’m pretty sure the French plant will be built. The first-quarter report includes photos of demolition and preparation at the site, a former coal-fired power plant. And the EU and France are motivated to make it happen. But many stars will need to align for Circa to realize its plans for an even larger facility somewhere in the US or Europe and to be producing 80,000 t per year of Cyrene by 2030.

To be clear, I would like to see the company and its solvent succeed. Cyrene is a great example of how the chemical enterprise can make life on this planet more sustainable. And organic chemist Bruce Lipshutz told Boerner that chemists and the chemical industry can’t keep doing things the way they do now. It’s just very hard to find a new way.

Views expressed on this page are those of the author and not necessarily those of ACS.


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