According to a new study, millions of tons of a class of extremely reactive chemicals called hydrotrioxides can linger in the atmosphere for several hours – which could impact human health and the global climate.
The chemicals interact extremely quickly with other compounds, and their presence means chemists have to rethink how processes in the atmosphere work.
It was long thought that hydrotrioxides – chemical compounds containing one hydrogen atom and three oxygen atoms – were too unstable to last long in atmospheric conditions.
But the new research instead shows that hydrotrioxides are a regular product of many common chemical reactions and that they can remain stable enough to react with other compounds in the atmosphere.
“We showed that the lifetime of one of them was at least 20 minutes,” Henrik Grum Kjærgaard, a chemist at the University of Copenhagen, told Live Science. “So that’s long enough for them to be able to do stuff in the atmosphere.”
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Kjærgaard is one of the authors of a new study on hydrotrioxide formation in the atmosphere, published online May 26 in the Journal Science (opens in new tab).
The discovery doesn’t mean anything new is happening in the atmosphere; on the contrary, hydrotrioxides seem to have always formed there. But the new study is the first time the existence of these ultra-reactive chemicals in the atmosphere has been confirmed.
“We can now show through direct observation that these compounds do indeed form in the atmosphere, that they are surprisingly stable, and that they are formed from almost any chemical compound,” said PhD student Jing Chen of the University of Copenhagen, the study’s second author , said in a statement (opens in new tab). “All speculation must be settled now.”
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Hydrotrioxides are a type of hydrogen polyoxide. Water is the simplest and most common hydrogen polyoxide, containing two hydrogen atoms and one oxygen atom, or H2O.
Another hydrogen polyoxide is hydrogen peroxide, which has two oxygen atoms—H2O2—and is commonly used as a bleach or disinfectant. The extra oxygen atom also makes many peroxides extremely flammable, and they are sometimes used as a component of rocket fuels.
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Hydrotrioxides are a step up in that they have three oxygen atoms bonded together, making them even more reactive than peroxides. They are chemically written as ROOOH, where R is any attached group, e.g. B. a carbon group.
But while it is known that peroxides can form from chemical reactions in the atmosphere, it was not previously known that hydrotrioxides can also form there, albeit for a relatively short time, before breaking down into less reactive chemicals.
In the new study, the researchers estimate that about 11 million metric tons (10 million metric tons) of hydrotrioxides form in the atmosphere each year as a product of one of the most common reactions: the oxidation of isoprene, a substance produced by many plants and animals and the main component of natural rubber is.
The researchers estimate that about 1% of the isoprene released into the atmosphere forms hydrotrioxides and that they arise from these reactions in very small concentrations – about 10 million hydrotrioxide molecules in one cubic centimeter of the atmosphere, which is only a very faint trace.
“We are super happy that we were able to show that [hydrotrioxides] are there and that they live long enough to be – most likely – important in the atmosphere,” study leader Torsten Berndt, an atmospheric chemist at the Leibniz Institute for Tropospheric Research (TROPOS) in Leipzig, told Live Science in an email.
Berndt led the research laboratory experiments at TROPOS to find out whether hydrotrioxides are actually formed by chemical reactions in the atmosphere, while the University of Copenhagen team studied the theoretical aspects of hydrotrioxide formation.
Berndt and his colleagues used very sensitive mass spectrometry to detect the ultra-reactive hydrotrioxides – a technique that can be used to determine the molecular weight of chemicals to find out what atoms they are made of.
The reactions to produce the hydrotrioxides took place in the TROPOS free jet flow system (opens in new tab)creating an airflow unobstructed by rigid restrictions.
And the study also used the results of experiments in an atmospheric chamber at the California Institute of Technology in Pasadena.
Now that their research has confirmed that hydrotrioxides are formed by common chemical reactions in the atmosphere, scientists will next examine how the compounds might affect human health and the environment during the minutes or hours of activity before the Decompose compounds, said Berndt.
“From the knowledge of organic chemistry, we can expect that [hydrotrioxides] It will also act as an oxidizer in the atmosphere,” he said. It’s also possible that hydrotrioxides could have an effect if our lungs breathe air that contains them in very low concentrations, “but that’s all very speculative at the moment.”
Berndt said hydrotrioxides could also penetrate atmospheric aerosols — very fine solid particles or liquid droplets suspended in the atmosphere, like the ash from volcanic eruptions or the soot from large fires — and trigger chemical reactions there. But “experimental studies on this are very challenging,” he said. “There is a lot to do.”
Originally) released on live science.
https://www.livescience.com/reactive-chemical-hydrotrioxides-atmospher New, extremely reactive chemical discovered in the atmosphere