Sunday, 11 February 2018

Talk : How Can Chemistry Save The World?

Returning for the first talk of the year, Cafe Sci persuade The Vat & Fiddle to open specially on the night of their staff party in order to welcome YouTube star Sir Martyn Poliakoff to talk on How Can Chemistry Save The World?

@Gav Squires was there and has kindly written this guest post summarising the event, with some linkage added by NSB....

Sir Poliakoff began by pointing out that the world needs chemicals - Earth could no support its current population with natural materials alone. For example, we need fertilisers for food and synthetic materials for clothing. Since 1969, the population of the planet has doubled and will very soon hit 7.6 billion people. In 2012, the Royal Society produced a report entitled The People & The Planet, which came to the conclusion that most of us consume too much. That’s despite the fact that there are 1.6 billion “profoundly poor” people on the planet who deserve to consume more. The usually definition of profoundly poor is someone who can recall all of their possessions from memory.

UN population projections

  Today, more people in the world use a mobile phone than use a toothbrush. Smartphones contain 50 different chemical elements, out of 89 that are non-radioactive, and many of these are in short supply. The list includes tungsten, needed to make your phone vibrate and indium, used on the inside of the touch screen as it’s see-through and conducts electricity. You can’t get rid of an element without a nuclear explosion but it is possible to distribute it out so thinly that you can’t get it back together. This leads to the “Robin Hood” question - how can we provide for the poor without robbing the rich? Even the most altruistic aren’t going to accept a fall in their living standards.

Modern Circuit Board

Martyn is involved in “green chemistry”, the idea of making chemicals more cleanly and with less waste. He tells a tale of visiting Ethiopia 15 years ago and pointing out to an audience at a lecture that a plastic bag was made from petrol. So a poor country like Ethiopia was buying petrol products from Abu Dhabi, one of the richest nations, and are then throwing the bags away. In the market where the bags came from, there was a surplus of sugar cane - if the bags could be made of sugar cane waste [i.e. as a "bioplastic"] a then the petrol would no longer be required and cows could eat the waste. This is the idea of green chemistry. 15 years later and plastic bottles are now being made from sugar in Brazil. As a follow up when one of Martyn’s friends at Procter & Gamble heard his anecdote about the bags in Ethiopia, he made him a bag from sugar. This is possible because when humans eat too much, we get fat but when bacteria eat too much they produce plastic. Hence, feeding them on sugar can lead to plastic bags.

Containers made from Bioplastic

Most of the chemicals that we use are organic and are based on carbon. These require a lot of solvents in order to make chemical reactions. So, one of the other aims of green chemistry is to reduce the amount of solvent required. For example when Viagra was first produced, it required 1,300 litres of solvent to produce 1 kilogram of product. Now, it requires just 6.5 litres. One of the ways of cutting down on solvent use is through super-critical fluids. If you heat liquid in a bottle then the density of the liquid goes down while the density of the gas increases. Eventually, the densities equalise and the line between liquid and gas disappears - the gas can now be used as a solvent in chemical reactions.

CO2 phase diagram

  Back in 1912, Ciamician had an article published in Science magazine entitled The Photochemistry of the Future and it is only now that the importance of his work is becoming apparent. We know that sunlight fades the colours of things such as book and curtains. Well, Ciamician was talking about the idea that coal is just fossilised sunlight and we all know that we will fun out of coal and oil long before we run out of sunlight. So, he postulated the idea of using radiant energy when looking for new methods of doing photo-chemical reactions.

Giacomo Luigi Ciamician

So, we're not quite there with green chemistry but it's encouraging the amount of work that's being put into it, especially right here in Nottingham.

Café Sci returns to The Vat & Fiddle on the 12th of February at 8:00pm when Liz Sockett will speak on Predatory Bacteria To Treat Infection. For more information, check out the Café Sci Meetup page:

Image Sources
Population, Circuit Board, Bottle, Phase Diagram, Ciamician

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