Tag Archives: sulfurous

Chemists show the existence of sulfurous acid in the gas phase in normal atmospheric conditions

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Chemists at the Leibniz Institute for Tropospheric Research have discovered that sulfurous acid (H2So3), once formed in the gas phase, is kinetically stable enough to allow its characterization and subsequent reactions.

In the gas phase, sulfurous acid, once formed, exhibits some kinetic stability with a lifetime of at least 1 second in atmospheric water vapor conditions. Image courtesy of Berndt others., doi:10.1002/anie.202405572.

Sulfurous acid Having formula H2So3 The molecular weight is 82.075 g/mol.

This molecule, also known as sulfuric acid(IV) or thioic acid, is a difficult-to-reach acid that has never before been observed in aqueous solution.

However, sulfite Detected It was discovered in the gas phase in 1988 by dissociative ionization of diethyl sulfite.

“The only experimental detection of sulfurous acid to date was achieved in 1988 by the team of Helmut Schwarz at the Technical University of Berlin using in situ generation with a mass spectrometer,” said Dr. Torsten Berndt of the Leibniz Institute for Tropospheric Research and colleagues.

“Under vacuum conditions, we estimated an extremely short lifetime of more than 10 microseconds.”

“Theoretical calculations show that H2So3 As a possible reaction product of the gas-phase reaction of OH radicals with dimethyl sulfide (DMS), which are produced from ozone and water molecules in the troposphere primarily in the presence of ultraviolet light.”

“DMS is produced primarily by biological processes in the ocean and is the largest source of biogenic sulfur in the atmosphere, producing approximately 30 million tonnes per year.”

The researchers experimentally investigated possible reaction pathways to H.2So3 It starts with DMS.

Formation of H2So3 Its formation in the gas phase was clearly demonstrated in a flow reactor under atmospheric conditions.

“Under our experimental conditions, sulfurous acid remained stable for 30 seconds, regardless of humidity,” the researchers said.

“With the existing experimental setup, longer residence times have not yet been explored.”

“Therefore, H2So3 It may persist in the atmosphere long enough to affect chemical reactions.”

“The observed yields were somewhat higher than theoretically expected.”

According to related model simulations, about 8 million tons of H2So3 They form every year all over the world.

“In this pathway, the mass of H increases by about 200 times.2So3 Sulfuric acid (H2So4“It produces carbon dioxide (CO2) from dimethyl sulfide in the atmosphere,” said Dr Andreas Tilgner and Dr Eric Hofmann from the Leibniz Institute for Tropospheric Research.

“The new results may contribute to a better understanding of the atmospheric sulfur cycle.”

Team paper Published in the journal Applied Chemistry.

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Torsten Berndt others2024. Gas-phase production of sulfurous acid (H)2So3) floats in the atmosphere. Applied Chemistry 63(30):e202405572;doi:10.1002/anie.202405572

Source: www.sci.news

Astronomers say that a near, warm Neptune has a sulfurous atmosphere

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The warm Neptunian exoplanet, called GJ 3470b (Gliese 3470b), is 96 light years away and orbits a 2 billion year old red dwarf star in the direction of the constellation Cancer.

Artist's impression of the warm-Neptunian exoplanet GJ 3470b. Image courtesy of the University of Wisconsin-Madison Department of Astronomy.

First discovered in 2012, GJ 3470b is the lightest and coolest (over 325 degrees Celsius, or 600 degrees Fahrenheit) exoplanet containing sulfur dioxide.

The compounds are likely a sign of active chemistry taking place in the planet's atmosphere, as radiation from a nearby star explosively breaks down hydrogen sulfide components, which then seek out new molecular partners.

“We never expected to see sulfur dioxide on such a small planet, so finding this new molecule in an unexpected place is exciting because it gives us new ways to understand how these planets formed,” said Professor Thomas Beatty of the University of Wisconsin-Madison.

“And small planets are particularly interesting because their composition depends heavily on how the planet-formation process happened.”

Prof Beatty and his colleagues hope that by observing what exoplanets contain, they can shed light on the principles of planet formation and do just that.

“The discovery of sulphur dioxide on a small planet like GJ 3470b adds another important item to the list of ingredients for planet formation,” Prof Beatty said.

In the case of the GJ 3470b, there are also other interesting features that could help round out that recipe.

The planet orbits the star and passes nearly over the star's pole, meaning that it orbits at a 90 degree angle to the expected orbit of a planet in this system.

The moon is also incredibly close to its star, close enough that light from the star would blow a lot of GJ 3470b's atmosphere out into space.

The team says the planet may have lost around 40% of its mass since it formed.

The misaligned orbit suggests that GJ 3470b was once somewhere else in the system, and at some point, the planet became caught in the gravity of another planet, pulling it into a new orbit and eventually settling in a different neighborhood.

“The migration history that led to this polar orbit and how it has lost so much mass are things we don't typically know about other exoplanet targets that we study,” Prof Beattie said.

“These are important steps in the recipe that created this particular planet, and they help us understand how planets like this one are made.”

“Further analysis of the components remaining in the planet's atmosphere may help us understand why planets like GJ 3470b became so appetizing.”

This month, the authors 244th Meeting of the American Astronomical Society In Madison, Wisconsin.

Source: www.sci.news