Hydrogen bonds in water clusters help catalyse acid rain formation via a mechanism more typically found in organic synthesis, new research shows.
Burning fossil fuels, volcanic eruptions and soil bacteria release oxides of sulfur and nitrogen into the air. High in the atmosphere, these oxides transform into sulfuric acid and nitric acid – which falls as acid rain.
Source: © Royal Society of Chemistry
Comparison between a typical bifunctional catalyst in synthetic organic chemistry (left) and the embedded water molecules in the supramolecular complexes (H2O)2⋯SO3 (middle) and (H2O)3⋯SO3 (right). Red = oxygen, grey = carbon, blue = nitrogen, yellow = sulfur, white = hydrogen
Sulfuric acid, in particular, forms when sulfur trioxide reacts with atmospheric water. During the reaction, hydrogen bonds organise sulfur trioxide and water into a stable supramolecular complex called an adduct, which facilitates an unusual nucleophilic attack by water. However, the precise mechanism behind this nucleophilic behaviour has long been unclear.
Read the full story by Thomas Foley in Chemistry World.
This article is free to access until 17 April 2017.
E Romero-Montalvo et al., Chem. Commun., 2017, DOI: 10.1039/c6cc09616f
