Refrigerant replacement highly toxic on combustion

EU regulations suggest refrigerants in car air conditioning systems are replaced with a more environmentally friendly version, but scientists are urging a rethink after studies showed the recommended replacement releases toxic chemicals upon combustion. Guidelines suggests that R1234yf – 2,3,3,3-tetrafluropropene – should be used as the refrigerant in car air conditioning systems, replacing R-134a (1,1,1,2-tetrafluroethane). However, the compound is inflammable, and in the event of a fire, the cooling agent would form the highly poisonous carbonyl fluoride said researchers from Ludwig-Maximilians-Universitaet München (LMU). “It has been known for some time now that combustion of R1234yf results in the production of the toxic hydrogen fluoride,” said Andreas Kornath, Professor of Inorganic Chemistry. “Our analysis has now shown that 20% of the gases produced by combustion of the compound consist of the even more poisonous chemical carbonyl fluoride.” Carbonyl fluoride is structurally related to phosgene which was used as a chemical weapon during the First World War. It is even more dangerous than phosgene – which is highly corrosive – and penetrates the skin incredibly quickly. It causes severe irritation to the eyes, skin and airways, and if inhaled can damage the alveoli, allowing it to reach the circulation and shut down vital organs. EU guidelines say that car manufactures are legally obliged to use an environmentally friendly refrigerant in air conditioning units in their cars to replace R134a – which has been forbidden in the EU since 2011. There is serious debate concerning its recommended replacement, R1234yf, in Germany. Studies carried out by various institutions and German car manufacturers pointed to the compound’s flammability and in the event the vehicle catches fire, the release of carbonyl fluoride. “The risk analysis carried out by the manufacturers of the refrigerants so far have not taken carbonyl fluoride into account,” Kornath said. “In light of our results, we advise that the risks associated with R1234yf should be urgently reassessed.” However, in a statement made to Laboratory News the manufacturers of the chemical – Honeywell – downplay the recent report. “Carbonyl fluoride is in fact a well-known breakdown product of HFO-1234yf that has been publicly studied by leading experts in the automotive industry. It was studied in the 2007-2009 Cooperative Research Program (CRP) conducted by SAE International, the world’s leading automotive engineering organisation. The SAE CRP reviewed the COF2 data, included it in its risk assessment, and concluded that HFO-1234yf is safe for use in automotive air conditioning. In March, the EU’s Joint Research Centre also reviewed this data and again concluded that HFO-1234yf is safe for use in automobile air conditioning. COF2 is also formed during the burning of the current automotive refrigerant HFC-134a, used in hundreds of millions of vehicles worldwide today. When COF2 does form in such conditions, it only lasts for a fraction of a second, which is not long enough to put bystanders, passengers, or first responders in any danger.” The investigation has been published in the journal Zeitschrift für Naturforschung.