Green chemistry and solvents – Prof. Martyn Poliakoff – 05/03/12

5th March 2012

We all do our bit towards preserving our environment, whether that be recycling your bottles from last night’s house party, splashing out on local produce during the weekly shop, or getting the train home instead of driving.

But what impact do you think all the paper you use for notes has on the environment? Or your shampoo? Have you dared to think what bleach would do if it was allowed to leak into sensitive ecosystems?

Martyn Poliakoff

Our guest today is a pioneer in an area called Green Chemistry. Professor Martyn Poliakoff is also a youtube super star from the periodic table of videos, but his research focuses on developing methods for industry that involve as little hazard to the environment as possible. This includes replacing more harmful solvents with pressurised carbon dioxide.

So have your questions ready to text in this Monday evening, and tune in to challenge the way you think about your world…

This week in Student Science we play with fire, literally..
We played with methane in our Student Science video and Martyn brought in a model of the chemical structure which is also a dog toy!

Martyn and his dog toy!

Green chemistry metrics measures efficiency in a chemical process and the first general metric for green chemistry remains one of the best. Roger Sheldon’s E-factor can be made as complex and thorough or as simple as required.
The E-factor calculation is defined by the ratio of the mass of waste per unit of product:

E-factor = total waste (kg) / product (kg)

Carbon dioxide pressure-temperature phase diagram Martyn particularly specialises in reducing or removing solvents from production methods. This is particularly important as so many things are made from fossil fuels which need solvents in production.

Carbon dioxide and steam are possible solutions that are being looked into, you can compress the gasses and reach the critical point to make them into supercritical fluids which can then act like solvents and lubricate things in production.

In fact carbon dioxide is being used more and more by coffee manufacturers. The supercritical carbon dioxide is forced through green coffee beans which are then sprayed with water at high pressure to remove the caffeine. This caffeine can then be removed from the water by passing it through activated charcoal filters or by distillation, crystallization or reverse osmosis. This then can be sold to people such as caffeinated drinks companies.

Dave, Martyn and Emma