A new study suggests that millions of tons of a class of extremely reactive chemicals called hydrotrioxides may remain in the atmosphere for several hours – which could have consequences for human health and the global climate.
Chemicals interact with other compounds extremely quickly, and their presence means that chemists will have to rethink how processes in the atmosphere are going.
Hydrotrioxides – chemical compounds that contain a hydrogen atom and three oxygen atoms – have long been thought to be too unstable to last long under atmospheric conditions.
But new research instead shows that hydrotrioxides are a common product in many common chemical reactions and can remain stable enough to react with other compounds in the atmosphere.
“We showed that the lifespan of one of them was at least 20 minutes,” said Live Science Henrik Grum Kjærgaard, a chemist at the University of Copenhagen. “So it’s long enough for them to do things in the atmosphere.”
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Kjærgaard is one of the authors of a new study on the formation of hydrotrioxide in the atmosphere published online 26. Science magazine (opens in a new tab).
The discovery does not mean that something new is happening in the atmosphere; rather, hydrotrioxides have always been formed there. But the new study is the first time the existence of these ultra-reactive chemicals in the atmosphere has been verified.
“We can now show by direct observation that these compounds are actually formed in the atmosphere, that they are surprisingly stable, and that they are made up of almost all chemical compounds,” said Jing Chen, a doctoral student at the University of Copenhagen. , stated in the statement (opens in a new tab). “All speculation must now be curbed.”
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Hydrotrioxides are a type of hydrogen polyoxide. Water is the simplest and most common polyoxide of hydrogen with 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 is sometimes used as part of rocket fuels.
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Hydrotrioxides are a step further because they have three oxygen atoms attached to them, making them even more reactive than peroxides. Chemically written as ROOOH, where R is any bonded group, for example a carbon group.
However, although it is known that peroxides can be formed by chemical reactions in the atmosphere, it was not previously known that hydrotrioxides could also be formed there, albeit for a relatively short time before decomposing into less reactive chemicals.
In a new study, scientists estimate that about 11 million tons (10 million metric tons) of hydrotrioxide are formed 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 plants. animals and which is a major component of natural rubber.
The researchers estimate that about 1% of the isoprene released into the atmosphere is hydrotrioxides and that they are produced by these reactions in very low concentrations – about 10 million molecules of hydrotrioxide per cubic centimeter of atmosphere, which is only a very weak trace.
“It simply came to our notice then [hydrotrioxides] they are there and they live long enough to be – most likely – important in the atmosphere, “Torsten Berndt, an atmospheric chemist at the Leibniz Institute for Troposphere Research (TROPOS) in Leipzig, Germany, told Live Science. by e-mail.
Berndt led experiments from a research laboratory at TROPOS to find out if hydrotrioxides were actually produced by chemical reactions in the atmosphere, while the University of Copenhagen team studied the theoretical aspects of how hydrotrioxides are formed.
Berndt and colleagues used very sensitive mass spectrometry to detect ultrareactive hydrotrioxides – a technique that can determine the molecular weight of chemicals and find out what atoms they are made of.
Reactions leading to the formation of hydrotrioxides took place in TROPOS free flow system (opens in a new tab)which creates an unobstructed airflow through fixed boundaries.
And the study 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 normal chemical reactions in the atmosphere, scientists will further investigate how compounds can affect human health and the environment within minutes or hours of activity before the compounds decompose, Berndt said.
“We can expect that from the knowledge of organic chemistry [hydrotrioxides] It will also act as an oxidant, “he said. It is also possible that hydrocarbon oxides could affect our lungs breathing air that contains them in very low concentrations,” but it’s all very speculative at the moment. “
Berndt said hydrotrioxides can also penetrate atmospheric aerosols – very fine solid particles or liquid droplets suspended in the atmosphere, such as ash from volcanic eruptions or soot from large fires – and can initiate chemical reactions there. But “the experimental investigation is very challenging,” he said. “There’s a lot of it.”
Originally published on Living science.
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