Researchers from Wageningen University & Research and Utrecht University have developed a method to produce a versatile chemical building block from plant residues using electricity. The approach avoids toxic liquid bromine and uses a simpler reactor. The results have been published in ChemSusChem.
The chemical industry relies heavily on fossil fuels and hazardous processes. A new study by chemists from Wageningen and Utrecht shows how this can be done differently: using agricultural waste as a raw material and electricity as the power source.
This concerns the production of 2(5H)-furanone, a substance that serves as an intermediate for plastics, medicines, and fragrances and flavorings. The researchers produce this compound from furfural, a liquid derived from sugars in plant-based waste streams such as straw or other agricultural by-products.
Broom without storage
Converting furfural to furanone was already possible, but this typically required liquid bromine: a toxic, corrosive substance with strict safety requirements for storage and transport. In the new approach, the researchers use bromide salts, such as sodium bromide, relatively harmless compounds in which bromine occurs in a bound form.
In an electrochemical reactor, the salt is converted by an electric current, after which bromine is released only at the site and moment of the reaction and immediately continues to react. As a result, chemical companies do not need to maintain stocks of hazardous substances, which significantly improves the safety of the process.
Cheaper reactor, smarter approach
Previous electrochemical attempts for this type of reaction used so-called shared cells: reactors with two compartments separated by a membrane. That membrane prevents unwanted interactions, but it is expensive, wears out quickly, and requires extra energy because ions must be forced through it with some force.
The Wageningen approach works without a membrane, in a so-called undivided cell. It is cheaper and more energy-efficient, but comes with a risk: all substances are contained together in a single compartment and can form unwanted byproducts. By adding a small amount of sulfuric acid, the researchers were able to better control the reaction and reduce those byproducts. Energy consumption remained very limited in the process.
Small beginnings, big ambition
The results are promising, but the scale is modest for now: the researchers produced only 0,3 milliliters of furanone, sufficient to analyze and optimize the reaction. According to the researchers, this is characteristic of fundamental research: first understand the underlying chemistry, and only then consider scaling up and application.
Whether the method will ever become industrially applicable depends on further optimization and cost comparisons with existing routes. The researchers are optimistic. The combination of renewable electricity and plant-based raw materials aligns well with the growing interest in biobased chemistry. According to those involved, the mild reaction conditions and the possibility of local production make the approach relevant for the future of the European chemical industry.
Source: Wageningen University & Research
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