Researchers create malaria medicine with solar reactor

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Researchers create malaria medicine with solar reactor

Researchers at the Technical University of Eindhoven have succeeded in making a malaria medicine with the help of a solar reactor. According to the researchers, this is just one of the possibilities offered by this device. Will further application of this technology follow in the chemistry field? ‘I can imagine that consumers will want chemicals in clothing to be made in a green and circular manner.’

Use of sunlight in chemical processes is a popular idea in chemistry. Many processes are thermal, requiring the heating of a reactor. Use of solar energy instead of fossil fuels for these processes can make the industry cleaner and more economical.

One problem, however, is that there does have to be sufficient energy in order to help put the chemical processes in motion. ‘Sunlight contains a lot of energy, but the difficult part is collecting and using this light with a high degree of efficiency,’ says Associate Professor of Chemistry at the Technical University of Eindhoven Dr. Timothy Noël. Nevertheless, there are sufficient examples in nature from which to learn. Even very deep on the ocean floor there are bacteria that can grow despite the limited quantity of light.

Three versions of the reactorThree versions of the reactor

Noël and his research team at the Technical University of Eindhoven succeeded in developing a solar reactor that is able to bring about chemical reactions. In 2016 Noël and his colleagues unveiled their mini-reactor for making medicines. The discovery of this worldwide unique reactor, which has the form of a leaf as a nod to the photosynthesis process, attracted a lot of attention at the time.  

Last year marked the first successful attempt at making medicine with the solar reactor. The medicine in question is the malaria drug artemisinin: ‘Normally, this medicine is extracted from a plant. With our method the plant’s yield can be increased,’ says Noël. Above all, the discovery makes it possible to make medicines wherever you want, for example in the middle of the jungle, in a less expensive and more sustainable way. An article about the reactor was published in August in the scientific journal Angewandte Chemie (Applied Chemistry).

Just like a leaf

The chemist developed the mini-reactor during his Vidi project Sensitized photoredox catalysis in continuous microfluidic reactors. The artificial leaf consists of luminescent solar concentrators, materials that are often used in solar cells. These materials absorb the sunlight in the same manner as the antenna molecules of a tree leaf. The reactor converts the sunlight into red light. The artificial leaf contains microchannels into which a liquid can be pumped. The energy of the absorbed sunlight comes into contact with the substance, causing a chemical reaction and a more complex substance to come out of the reactor, Noël explains. Compared to the reactor of two years ago, the researchers have also developed different reactors in the meantime which bring about different types of chemical reactions.

Click on the image to watch a video on YouTubeClick on the image to watch a video on YouTube

Noël thinks that medicines are only one of the possible applications of the technology. The fact that the researchers chose the pharmaceutical sector is due to Noël’s background: ‘I used to be active in the pharmaceutical field at MIT. We’ve now focused on this area, but in principle there are no limitations. Of course, it’s not the case that the technology can be used for every chemical process.’ In addition to medicines, Noël is thinking of agrochemistry, high-end molecules, materials or polymerisations used to make plastic or nylon, for example.

Possible dips in solar power are intercepted by the reactor itself, because it uses a light recognition system that adjusts the pump speed when there are lots of clouds, for example. This is important, because it’s a problem that can prevent chemical manufacturers from using the reactor, Noël believes. ‘Because the pump speed is adjusted, the quality of the end product remains guaranteed,’ the chemist explains. ‘This should be sufficient for the smaller-scale production of molecules.’

Working on upscaling

An important advantage of the reactor itself is that it renders fossil fuels unnecessary. ‘This is more sustainable, cleaner and more efficient’, says Noël. ‘So why aren’t we using it where we can?’ The chemist thinks that the technology is scalable. ‘We are now working on solar reactors measuring a half a metre by a half a metre. These can be easily placed on the roofs of factories.’ The researchers are running into practical issues, however. For example, they want to generate sufficient energy to also have the pump run on solar energy, and the distribution across the various channels in the reactor is not yet uniform. But Noël believes that these are issues that can be solved.

Although it will likely take a while before the technology is used in the chemical industry, Noël thinks. He says that there is a lack of a strong incentive. ‘Companies can also use LED lamps as a light source, and energy is very inexpensive, so why would they start using solar energy?’ The chemist thinks that political pressure is needed to get companies to switch. ‘The government could obligate companies to manufacture the products in their portfolio based on green energy instead of on fossil fuels.’

A greener image of the chemical sector

On the other hand, he is also hearing from the chemical sector that there is a need for greener production methods. ‘It is not always easy for companies in this sector to get a licence, given their image as polluters. Hence technology that runs on solar energy and offers the possibility of sufficient and high-quality production is interesting for them. I sometimes compare it to biolabels in the food industry. They allow companies to ask for something extra. People buy these types of products, creating pressure on other companies in the sector.’

In this sense, the tide is favourable for these kinds of technologies. Noël wonders why the consumers’ need for ‘green’ products could not apply to the chemical industry as well. ‘People choose green energy and are willing to pay for it. I can imagine that consumers will also want chemicals in clothing, for example, to be made in a green and circular manner.’ Noël adamantly believes this, even though he does think that it is still far off in the future: ‘I consider it to be blue-sky thinking. Implementing new technology can sometimes take a long time. I do notice that there is a lot of attention being paid, though. It’s a good idea. But it’s a long road from idea to application.’

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