- For the first time, Oxford chemists have generated fluorochemicals – critical for many industries – without the use of hazardous hydrogen fluoride gas.
- The innovative method was inspired by the biomineralization process that forms our teeth and bones.
- The results are published today in the leading journal Science.
Newswise — A revolutionary breakthrough has been achieved by a team of chemists who have successfully developed a brand new technique for producing essential fluorochemicals without the use of hazardous hydrogen fluoride (HF) gas. This groundbreaking discovery, recently published in Science, holds the potential to significantly enhance both the safety and environmental impact of the rapidly expanding global fluorochemical industry.
Fluorochemicals play a critical role in a wide range of applications, including polymers, agrochemicals, pharmaceuticals, and the lithium-ion batteries found in smartphones and electric vehicles. The global market for these chemicals amounted to a staggering $21.4 billion in 2018. Presently, all fluorochemicals are generated through an energy-intensive process involving the use of toxic and corrosive hydrogen fluoride (HF) gas. Despite stringent safety measures, HF spills have led to multiple incidents in recent decades, resulting in fatal accidents and serious environmental consequences.
To address these safety concerns, the team of chemists collaborated with experts from the University of Oxford, the Oxford spin-out company FluoRok, University College London, and Colorado State University. They drew inspiration from the natural biomineralization process that forms teeth and bones. Traditionally, HF is produced by reacting a crystalline mineral known as fluorspar (CaF2) with sulfuric acid under harsh conditions before being used to create fluorochemicals. However, the innovative method developed by the team enables direct production of fluorochemicals from CaF2, entirely bypassing the need to produce HF. This achievement represents a goal that chemists have pursued for decades.
In this groundbreaking process, solid-state CaF2 undergoes activation through a biomineralization-inspired approach, mirroring the way calcium phosphate minerals form in teeth and bones. The team achieved this by grinding CaF2 with powdered potassium phosphate salt in a ball-mill machine for several hours, utilizing a mechanochemical process inspired by traditional methods of grinding spices with a pestle and mortar.
The revolutionary product, dubbed Fluoromix, resulted from the process, enabling the direct synthesis of over 50 different fluorochemicals from CaF2 with remarkable yields of up to 98%. This groundbreaking method holds immense potential for streamlining the current supply chain and reducing energy demands, contributing significantly to future sustainability objectives and minimizing the industry's carbon footprint.
An exciting aspect of this solid-state process is that it proved equally effective with both acid grade fluorspar (> 97% CaF2) and synthetic reagent grade CaF2. This represents a paradigm shift in the global manufacturing of fluorochemicals and has led to the establishment of FluoRok, a spin-off company committed to commercializing this cutting-edge technology and developing safe, sustainable, and cost-effective fluorinations. The researchers anticipate that this study will inspire scientists worldwide to devise disruptive solutions for complex chemical challenges, with the potential to benefit society as a whole.
Calum Patel, one of the lead authors of the study from the Department of Chemistry at the University of Oxford, expressed excitement about the invention of mechanochemical activation of CaF2 with a phosphate salt, recognizing it as a seemingly simple yet highly effective solution to a complex problem. While questions surrounding the underlying mechanisms persisted, collaborative efforts played a pivotal role in unraveling the mysteries and advancing understanding in this unexplored realm of fluorine chemistry. Patel emphasized the significance of multidisciplinary approaches and expertise in tackling significant challenges, highlighting the importance of the team's work in capturing this essence.
Professor Véronique Gouverneur FRS, the lead author from the Department of Chemistry at the University of Oxford, who conceptualized and spearheaded this study, expresses her excitement:
'The direct utilization of CaF2 for fluorination has been a long-sought holy grail in our field, and finding a solution to this challenge has eluded us for decades. The urgent need to transition to sustainable methods for chemical manufacturing, ones that have minimal or no adverse impact on the environment, has become a top priority. This transition can be accelerated through ambitious programs and a complete reevaluation of current manufacturing practices. Our study marks a significant step in this direction, as the method developed at Oxford has the potential to be adopted universally across academia and industry. By shortening supply chains, it can help minimize carbon emissions and offer increased reliability, particularly crucial given the fragility of global supply chains.'
The study Fluorochemicals from fluorspar via a phosphate-enabled mechanochemical process that bypasses HF will be published in Science online at 14:00 US Eastern Time (19:00 BST) on Thursday 20 July 2023, and in print on Friday 21 July 2023: http://www.science.org/doi/10.1126/science.adi1557
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