Water is a catalyst in explosions

The most abundant material on Earth exhibits some incredible properties when placed in extreme conditions.

Lawrence Livermore National Laboratory scientists have shown that water, in hot environments, plays a role in catalyzing complex explosive reactions. The catalyst is a compound that accelerates chemical reactions without being consumed. Platinum and enzymes are common catalysts. But water is rarely, if ever, a catalyst under normal conditions.

Large explosions formed from oxygen and hydrogen produce water at thousands of degrees K and up to 100,000 Atmofe pressure , similar to conditions inside giant planets.

While the properties of pure water at high pressure and temperature have been studied for many years, the 'extreme' water in the reaction environment has never been touched.

Using the atomic simulation of a PETN (pentaerythritol tetranitrate) explosion, the team found that in water, when hydrogen ions act as a reducing agent, and hydroxide (OH) ions act as oxidants, then ions act as a group of motions that move oxygen between reaction centers.

Main author Christine Wu, said: 'This is completely new to us. It shows that water can stimulate reactions in explosions and inside planets'.

This finding goes against the current view that water is simply a stable product.

Wu said: 'Under extreme conditions, water becomes unusual due to continuous analysis. When you put it in the same condition as a planet, the hydrogen of a water molecule starts to move very fast. '

Simulation of the detonator in a large explosion shows that "extreme water" (molecules with red hydrogen atoms and two white oxygen atoms) can act as a catalyst to send oxygen back and forth between locations. react. (Photo: Lawrence Livermore National Laboratory)

In molecular simulation using BlueGene L supercomputer, Wu and colleagues Larry Fried, Lin Yang, Nir Goldman and Sorin Bastea discovered that hydrogen (H) and hydroxide (OH) ions in the water transport oxygen from nitrogen. to carbon under PETN explosion conditions (temperatures from 3,000 K to 4,200 K). Due to both temperature conditions, 'extreme water' acts as the final product and the main catalyst.

For an explosion of carbon, nitrogen, oxygen and hydrogen, such as PETN, three major gas products are water, carbon dioxide and nitrogen molecules.

But to this day, the chemical process leading to these stable compounds is not well understood.

The team found that nitrogen lost its oxygen to hydrogen, not carbon, even after the water concentration reached the equilibrium point. They also found that carbon atoms receive oxygen primarily from hydroxide, not directly from nitrogen monoxide (NO) or nitrogen dioxide (NO2). Meanwhile water separates and recombines with hydrogen and hydroxide on a regular basis.

Wu said: 'The water formed is part of the mechanism of energy release. The catalytic mechanism is completely different from the decomposition mechanism of PETN or similar explosive reactions, in which water is only the final product. This new discovery is important for scientists studying the internal chalk of Uranus and Neptune. '

The study was published in a special issue (April 2009) by Nature Chemistry magazine.

Refer:
Christine J. Wu, Laurence E. Fried, Lin H. Yang, Nir Goldman & Sorin Bastea.Catalytic behavior of dense hot water.Nature Chemistry, 2009;1 (1): 57 DOI: 10.1038 / nchem.130