Janek Betting, Leon Lefferts, and Jimmy Faria from the Catalytic Processes and Materials group (CPM) have recently published an article in the Chemical Communications Journal, by the Royal Society of Chemistry.
Over the last 20+ years the of the Catalytic Processes and Materials Group at Universiteit Twente has made key contributions to our understanding on the hydrogenation of nitrate and nitrite in drinking water using supported metal catalysts. Now, Janek Betting has discovered that this reaction is even more complex than what we have thought. He found that nitrate and nitrite lead to the formation of hydroxylamine (NH2OH), which is a major reaction intermediate reaching yields as high as 56% depending on the catalyst and reaction conditions used.
How could this be overseen for so long?
In chemistry and chemical engineering, achieving a closed mass balance is fundamental. However, in the nitrate and nitrite hydrogenation reaction there are sever challenges to actually achieve that. Thus, during the last ~3 decades it was widely accepted by researchers all over the world that ammonia and nitrogen are the only relevant reaction products in the thermocatalytic nitrate and nitrite hydrogenation. While ammonia is analytically determined, nitrogen is just assumed to be the remaining fraction. In contrast, desorption of hydroxylamine was not considered.
To prove the existence of hydroxylamine Janek developed a simple but powerful derivatization protocol based on the oximation reaction between the hydroxylamine and benzaldehyde. The resulting Benzaldehyde oxime can easily be quantified using HPLC-UV-vis. This strategy has already gained attention from companies and other research groups based on recent conferrence contributions.
Currently, they are working hard to systematically revise the full product distribution picture to better understand how the selectivity of this environmentally relevant reaction is determined.
Please find the full paper here: https://doi.org/10.1039/D5CC02803E
