[LUM#8] Toward Greener Chemistry
By revisiting the traditional technique of the mortar and pestle, researchers at theMax Moussseron Institute of Biomolecules have developed mechanochemical processes that enable the production of new molecules without the use of toxic solvents. Another step toward greener chemistry.
What do a jar of moisturizer, a migraine medication, and a plastic bottle have in common? All of these products are the result of organic chemistry.“Through its synthetic processes, this branch of chemistry—which focuses on compounds containing carbon atoms—contributes to the production of a wide range of everyday products,” explains Frédéric Lamaty, a chemist at the Max Moussseron Institute of Biomolecules (IBMM).
A process that relies on a key ingredient: solvents.“They’re used to facilitate contact between the different reactants and create new molecules,” explains the chemist. The problem: these organic solvents are far from harmless.“They are highly polluting to the environment; they are sometimes accidentally released into the natural world, with serious consequences such as the pollution of rivers, seas, and groundwater,” warns the researcher. The solvents are also toxic to those who handle them and pose a double health hazard, as these volatile, explosive, and flammable products must be handled with extreme caution.
How can we reconcile this use with the need to develop green chemistry that is more environmentally friendly? To minimize the damage, solvents can be recovered and recycled.“But there is a completely different, promising, and innovative approach: the development of entirely new processes that eliminate the need for solvents by using grinding,” explains Frédéric Lamaty (“A mechanochemical approach to access the proline–proline diketopiperazine structure,” 2017, in Bildstein Journal of Organic Chemistry).
An ancient technique
New processes inspired by traditional techniques. “It’s nothing more and nothing less than the mortar-and-pestle technique,” explains the researcher. The idea is simple: by mechanically “mixing” different solid substances, we can synthesize new molecules just as we do with solvents. Why has this technique, known as mechanochemistry, been neglected for so long by organic chemistry?“The idea that synthesis couldn’t occur without solvents took hold among scientists as far back as antiquity, when translation errors from Greek to Latin led to the misinterpretation of a phrase by Aristotle suggesting that liquids mix better than solids,”explains Frédéric Lamaty.
A blunder that long hindered the development of solvent-free organic chemistry.“Yet isolated studies using tools as rudimentary as a mortar and pestle had already demonstrated the possibility of carrying out organic chemical reactions via mechanochemistry.” While the number of researchers working on mechanochemistry remains very small, the technique could well develop to meet the challenges of greener chemistry. “To ‘mix’ solids even more effectively, as Aristotle put it, chemists have recently turned to ball mill-type equipment capable of generating greater grinding efficiency with less effort on the part of the operator and larger quantities of product, ”says the IBMM chemist, a pioneering laboratory in mechanochemistry with a team dedicated to this research for over 15 years.
Manufacturing medicines
Thanks to mechanochemistry, researchers are able to synthesize new molecules that are generating enormous interest, particularly from the pharmaceutical industry. “Our team at IBMM, for example, has succeeded in producing a peptide—a bioactive molecule that is a very promising candidate for developing a new drug, ”explains the chemist. More comprehensive studies now make it possible to consider the production of peptide drugs prepared without solvents using mechanochemistry.“We are also working on the synthesis of new molecules that could be of major interest to the electronics industry,”the researcher notes.
With cleaner molecules for greener chemistry, mechanochemistry has a bright future ahead.“The need to embrace sustainable development has led to the emergence of a disruptive technology yielding original scientific breakthroughs, ”notes Frédéric Lamaty. “All that remains is to convince a larger number of organic chemists of the scientific, technical, economic, and ecological benefits of the method, especially since a promising new mechanochemical approach—this time using reactive extrusion—is currently being developed.”
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