In a development that could reshape how chemists recycle one of the most persistent classes of synthetic molecules ever made, researchers have reported a new catalytic strategy that strips fluorine atoms from perfluoroalkyl chains in a controlled, sequential fashion while installing a single boron group at the chain’s terminus. The work, published in Nature Communications, introduces what the authors call zipper polydefluorination-monoborylation, a transformation that walks down a perfluoroalkyl skeleton and removes multiple fluorine atoms in a stepwise cascade before capping the partially defluorinated product with a boron substituent. The achievement addresses a longstanding challenge in fluorine chemistry: while carbon-fluorine bonds are prized in materials and pharmaceuticals for their extraordinary stability, that same stability makes them notoriously difficult to break selectively, leaving chemists with few tools for converting perfluorinated waste streams into useful building blocks.

Perfluoroalkyl substances, often grouped under the umbrella of PFAS chemistry, owe their remarkable properties to the strength of the carbon-fluorine bond, which at roughly 485 kilojoules per mole in fully fluorinated chains ranks among the strongest single bonds that carbon forms. This bond strength, combined with the sheer electronegativity of fluorine, means that perfluoroalkyl groups resist oxidation, hydrolysis, and thermal degradation under nearly all conventional conditions. As a consequence, perfluorinated chains accumulate in the environment and resist standard degradation pathways, prompting intensive research into defluorination methods ranging from photocatalytic single-electron transfer to reductive hydrodefluorination with metal hydrides. Yet most existing approaches suffer from a common limitation: they either remove fluorine indiscriminately, collapsing the entire chain to a mixture of products, or they remove only a single fluorine atom, offering little control over the degree of defluorination. The new study demonstrates a way to achieve the best of both worlds, delivering multi-fluorine removal in a predictable pattern while simultaneously introducing a versatile functional handle.

The conceptual heart of the method lies in what the authors describe as a zipper mechanism. Rather than removing fluorine atoms at random positions along the chain, the reaction initiates at a defined site and then propagates along the perfluoroalkyl backbone one carbon at a time, much as a zipper opens tooth by tooth. At each step along the chain, a fluorine atom is expelled and replaced in sequence, with the reaction front advancing until a thermodynamic or kinetic stopping point is reached. The monoborylation component of the process ensures that once the zipper has run its course, the resulting olefinic or anionic intermediate is intercepted by a boron reagent, furnishing a product in which the boron group occupies a predictable position derived from the original perfluoroalkyl terminus. Organoboron compounds are among the most valuable intermediates in modern synthetic chemistry, serving as partners in Suzuki-Miyaura cross-coupling and as precursors to alcohols, amines, and halides, so their installation at a defluorination site effectively converts a chemical dead end into a synthetic launching pad.

Mechanistically, the transformation draws on the characteristic reactivity of organoboron reagents toward geminal difluoroalkenes, the partially defluorinated intermediates that arise when consecutive fluorine atoms are eliminated from a perfluoroalkyl chain. Perfluoroalkyl chains, when subjected to strong bases or reductive conditions, can undergo sequential beta-fluoride elimination events, each generating a more highly unsaturated species. The boron reagent in the reported system engages these unsaturated intermediates through addition pathways that install boron at the terminal carbon while generating a carbanionic center adjacent to the remaining difluoromethylene unit. That newly formed carbanion is perfectly positioned to expel another fluoride ion, regenerating an unsaturated handle one carbon further down the chain and setting up the next iteration of the cycle. This intimate coupling of borylation and defluorination is what gives the reaction its chain-walking character: each borylation event creates the conditions for the next defluorination event, and the process ripples along the chain until the fluorine reservoir is exhausted or the reagents are consumed.

The practical significance of the work becomes apparent when one considers the fate of the fluorine atoms themselves. In the zipper process, fluorine is released as fluoride ion, which under the reaction conditions is sequestered by silicon-containing trapping agents to form robust silicon-fluorine bonds. Fluorosilicates of this kind are stable, isolable, and, importantly, compatible with industrial processes for recycling fluorine back into hydrofluoric acid, the feedstock from which essentially all synthetic organofluorine compounds are made. In this sense, the method does more than transform perfluoroalkyl chains into borylated products; it also lays the groundwork for closing the fluorine cycle, recovering the fluorine content of persistent molecules in a form that can be fed back into the chemical economy. With global concern over PFAS contamination intensifying and regulatory pressure on fluorinated chemicals mounting, technologies that enable fluorine recovery rather than dilution into the environment carry considerable weight.

From a synthetic chemistry standpoint, the products of the reaction open multiple downstream avenues. Because the boron substituent is installed at a defined position on a partially fluorinated alkyl or alkenyl framework, the resulting molecules retain a programmable mixture of carbon-fluorine bonds and carbon-boron functionality. The remaining fluorine atoms can tune the lipophilicity, metabolic stability, and dipole moment of the scaffold, properties that are actively exploited in medicinal chemistry when designing fluorinated drug candidates. Meanwhile, the boron group serves as a convertible handle, allowing the defluorinated carbon center to be joined to aromatic rings through cross-coupling, oxidized to alcohols, or aminated in homologation reactions. In effect, the method converts a chemically inert perfluoroalkyl group, useful mainly as a passive coating or tail, into a functionalized partial-fluoro skeleton that can participate in the full toolkit of carbon-carbon and carbon-heteroatom bond formation.

The reported study also sheds light on the factors governing how far the zipper travels along a given chain. Chain length, the nature of the substituent anchoring the perfluoroalkyl group, and the stoichiometry of the base and boron reagent all influence the number of fluorine atoms removed and the distribution of products obtained. Through systematic variation of these parameters and careful analysis of the reaction mixtures by nuclear magnetic resonance spectroscopy and mass spectrometry, the authors map out the scope of the transformation across a range of perfluoroalkyl substrates, from short perfluoroethyl groups to longer chains approaching those found in commercial fluorosurfactants. Control experiments interrogating individual elementary steps support the proposed sequential elimination-addition mechanism and rule out alternative pathways involving radical fragmentation or random beta-scission, underscoring the unusually high degree of positional control the method achieves.

Beyond its immediate synthetic utility, the work contributes to a growing body of research aimed at taming the carbon-fluorine bond through the strategy of defluorinative functionalization. Over the past decade, chemists have developed an impressive repertoire of reactions that replace fluorine in perfluoroalkyl and fluoroarene substrates with groups ranging from hydrogen to sulfur, nitrogen, and carbon substituents. What distinguishes the zipper approach is its multiplicity and its directionality: instead of a single substitution event at a single site, the reaction performs many substitutions in a choreographed sequence along a chain, effectively treating the perfluoroalkyl group as a one-dimensional lattice to be patterned at will. This conceptual reframing, from defluorination as bond-breaking to defluorination as programmable editing, may inspire analogous strategies for other polyfluorinated motifs, including perfluoroarenes and perfluoropolyethers, two additional classes of highly persistent fluorinated materials.

Challenges remain before such chemistry can move from the laboratory bench to environmental remediation at scale. The reaction conditions reported rely on strong bases and moisture-sensitive boron reagents handled under inert atmosphere, and the substrates studied are discrete, soluble perfluoroalkyl compounds rather than the polymeric or adsorbed PFAS species that dominate environmental contamination. Scaling the chemistry will require sourcing boron reagents economically, managing the large quantities of fluoride generated, and integrating the transformation with upstream methods for extracting perfluoroalkyl pollutants from water and soil. Nevertheless, the demonstration that a perfluoroalkyl chain can be unzipped in a controlled manner, with fluorine captured in recyclable form and a valuable boron handle installed, establishes a credible chemical pathway toward defluorination that is both productive and selective, a combination that has eluded the field for decades.

As policymakers and scientists grapple with the legacy of fluorine chemistry, work of this kind illustrates a middle path between the wholesale abandonment of fluorinated molecules and their indefinite persistence in the biosphere. The fluorine atom confers properties that industry and medicine continue to depend upon, and the ability to disassemble fluorinated architectures on demand, recovering both the carbon skeleton as a functionalized building block and the fluorine content as a recyclable salt, points toward a more circular future for organofluorine chemistry. The zipper polydefluorination-monoborylation strategy reported in Nature Communications is an early but striking example of that vision made concrete at the molecular level, and it is likely to prompt rapid efforts to extend the concept across the breadth of persistent fluorinated chemicals.

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The problem of per- and polyfluoroalkyl substances, or PFAS, a group of potentially cancer-causing “forever chemicals,” may finally have a solution, thanks to German scientists.

The PFAS group contains more than 10,000 synthetic substances that refuse to break down, leading to the term “forever chemicals,” and which instead build up in the body to cause developmental issues, immune problems, and even cancer.

Now, Helmholtz-Zentrum Dresden-Rossendorf (HZDR) researchers have reported not one, but two new solutions to the forever chemical problem in recent papers published in the journals Chemical Engineering Journal Advances and Scientific Reports.

One of these new processes for addressing this long-standing environmental problem employs hydrodynamic cavitation, while the other employs cold atmospheric plasma combined with gas dispersion.

Forever Chemicals Explained

PFAS have exceptionally stable carbon-fluorine bonds, which make them difficult to break down. Through industrial wastewater, these forever chemicals are released into oceans and rivers, where they can accumulate in plants, animals, and humans. While some of them are tied to specific health risks, many are still question marks, with their health consequences unclear.

The work at HZDR is part of Germany’s “National Water Strategy,” aimed at protecting the country’s water supplies. In a 2022 preliminary study that the new work built on, researchers degraded PFAS chemicals through a hydrodynamic cavitation process.

Work on these new processes was conducted at the Helmholtz Center for Environmental Research (UFZ), confirming that both processes degrade PFAS and produce fluoride, which the researchers hope will soon be adopted in industry.

The First Solution

“In hydrodynamic cavitation, we pass PFAS-enriched water through a constriction, generating small vapor bubbles,” explained co-author Dr. Sebastian Reinecke, head of the Department of Water and Environmental Technologies at HZDR. “When the bubbles burst under the rising ambient pressure in the water downstream of the constriction, the PFAS that are attached to the bubbles are exposed to local temperature spikes of several thousand degrees Celsius.”

While this occurs, highly reactive hydroxyl radicals form during cavitation, which the team believes then attack intermediate products, hastening the breakdown of PFAS.

The researchers demonstrated that PFAS chemicals in tap water were broken down, with higher concentrations of fluoride produced as treatment duration increased. A persistent and well-studied PFAS, perfluorooctane sulfonate (PFOS), was used in the research, with 37% of the dissolved chemical eventually breaking down.

“We are now conducting follow-up experiments to increase the degradation rate,” Reinecke added. “Our goal is to improve the process to a degradation rate of more than 80 percent of the PFAS in the solution and mineralizing more than 50 percent of the fluorine that is bound in the chemicals – that means, breaking down the carbon-fluorine bonds that are typical of PFAS.”

Plasma Vs. PFAS

Dr. Amit Kumar, an environmental engineer at HZDR, led another series of experiments on cold atmospheric plasma and gas dispersion, which offered the advantage of not requiring catalysts or additional chemicals. Kumar applied some of his previous research on breaking down micropollutants to the problem of forever chemicals. 

“We generated plasma at the water surface while simultaneously introducing gas into the PFAS-contaminated water,” Reinecke explained. “The PFAS attach to the surface of the gas bubbles. As they rise, the water is constantly circulated. This brings the PFAS to the surface, where they are broken down in the plasma.”

Roughly 35% of the fluorine atoms in these forever chemicals were released as fluoride salts in the process, almost completely degrading long- and short-chain PFAS. 

“While this method has significantly faster reaction kinetics than cavitation, it also consumes far more energy per volume unit,” Reinecke notes. “In addition, the process generates numerous transformation products that we have not yet been able to investigate in detail – for instance, gaseous compounds that form during the reaction.” 

Scaling PFAS Degradation

With their central ideas proven, the researchers are now focused on scaling up these processes for industrial-scale wastewater applications. Part of this involves increasing the reaction volume from 50 milliliters to 5 liters and combining the two separate processes.

“I believe we’ll achieve high degradation rates by combining the highly reactive species from the plasma with the effects of cavitation,” says Reinecke.

Additionally, follow-up work is currently investigating whether any byproducts of the plasma process are harmful and how to mitigate those effects.

Merging the techniques could lead to a highly efficient new PFAS removal technology, providing a powerful tool for dealing with one of the most significant threats to clean water supplies.

The paper, “Enhanced Degradation and Defluorination of Perfluorooctane Sulfonate (PFOS) in Tap Water Using Gas-Dispersed Cold Atmospheric Plasma,” appeared in Scientific Reports on June 13, 2026, and the second study, “Degradation and Defluorination of Perfluorooctane Sulfonate (PFOS) Forever Chemical in Water Using Hydrodynamic Cavitation Treatment,” appeared in Chemical Engineering Journal Advances on March 26, 2026.

Ryan Whalen covers science and technology for The Debrief. He holds an MA in History and a Master of Library and Information Science with a certificate in Data Science. He can be contacted at ryan@thedebrief.org, and follow him on Twitter @mdntwvlf.

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