By Tyler Irving
Posted February 2012
Inspired by nature, which has a head start on humans when it comes to creating antifreeze, a team at the University of Ottawa has created a new molecule that prevents the formation of a special kind of ice — clathrate hydrates.
Clathrate hydrates form when water molecules crystallize into a cage-like structure that can contain one or more molecules of natural gas or other hydrocarbons. This happens only under low temperatures and high pressures, such as those found in deep ocean sediments, but also in pressurized gas or oil pipelines during a Canadian winter. Clathrate hydrates can plug pipes and lead to unpredictable pressure fluctuations. Currently, chemicals like methanol or high molecular weight polymers are used to prevent their formation. However, relatively high concentrations are required for these antifreeze molecules to be effective.
Robert Ben and his group in the Department of Chemistry have been studying natural antifreeze molecules found in organisms like fish and insects that live in cold environments. These molecules are high molecular weight glycoproteins and figuring out how they function is time-consuming. “We’ve been working in this area for more than a decade,” says Ben. “We’ve made many different molecules, but it’s really trial and error. It hasn’t been until the past two years that we’ve dialled into the structural criteria you need to get potent activity in a smaller molecule.” Using a technique called differential scanning calorimetry (DSC), Ben’s team has demonstrated that certain small molecules can prevent clathrate formation at one third the concentration of commercial products.
The new antifreezes are non-toxic and simple to make, so scaling up production should be straightforward. Working with GreenCentre Canada, Ben has applied for a patent and is looking for companies to produce the chemicals, which he thinks could be in commercial use within two to three years.
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