Green chemistry - better, safer, more sustainable

From safer solvents to make better batteries, to catalysts that can clean up wastewater, green chemists are developing better ways of making stuff.

James Wright and Cameron Weber are passionate advocates of an area of chemistry known as 'green chemistry.'

"It's where we design new processes and products that don't harm the environment," says James, who is Director of the Centre for Green Chemical Science at the University of Auckland.

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Traditional chemical processes, used at an industrial scale to make everything from shampoo and mobile phones to clothes and packaging, are often polluting and energy intensive.

Starting in the 1990s, chemists began to develop green solutions that were better, safer and more sustainable.

"We are both trying to minimise the environmental impact of chemistry and the chemical industry," says Cameron, "and also use chemistry to solve some environmental problems."

Cameron works with solvents, which traditionally are volatile. "You open a paint can, for example, and you get the fumes from the solvents that are present there."

Cameron says that solvents are often hazardous to health and flammable, as well as being derived from fossil fuels.

One approach, says Cameron, is to create solvents that will work at lower temperatures. This saves energy and is less hazardous.

He is also keen to develop new solvents that will allow more than one reaction to happen at the same time.

Ionic solvents are made from salts, which normally melt at very high temperatures. But if the solvent is made from large, asymmetrical ions you can create a salt that is liquid at room temperature and is inherently non-volatile.

Ionic solvents conduct electricity and could be used to make better batteries that are non-flammable.

Cameron says that another advantage is they can be made from common, widely available ingredients.

Ionic solvents made from iron are magnetic, and after it has done its job the solvent can be removed using a magnet.

Deep eutectic solvents are a special kind of ionic solvent which have a much lower melting point than the constituent ingredients. Choline chloride and urea have respective melting points of 302°C and 133°, but in combination their melting point is a mere 12°, which effectively means that two compounds that are solid at room temperature create a liquid when they are mixed together.

Cameron likens his job to being a designer, creating new compounds with interesting properties that might then be picked up and used by industry…

Go to this episode on rnz.co.nz for more details