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It’s Friday night! After a long day of lab work with exclusively successful reactions (as if that would ever happen…) you finally decide it’s about time to go out and meet some people again. No worries, you don’t have to go far, there is a faculty meeting down the hall with ethanol-based drinks and chemistry discussions, just the way you like to party (and what a party animal you are!).
After some drinks and chat you spot her, the girl you always wanted to ask out. She smiles at you but you just don’t know how to talk to her. What to say and how? Your hands get sweaty; you take another nervous sip hoping you can come up with a good opening line: “You like chemistry, don’t you?” No let’s face it, being charming is just not your thing. You need somebody who introduces you and get’s the thing going.
You need a CATALYST!
The principle of catalysis is everywhere. We encounter it in cars where toxic compounds are converted into less harmful ones. Our entire body works on catalytic systems based on enzymes, highly active biological catalysts (see video below). And we finally also meet them in synthesis in chemistry labs, where catalytic processes are arguably the most important field of research.
But what is catalysis really about?
And why should we discuss catalysis on a platform for sustainability?
Chemistry, just like dating, is not always an easy science. Putting two reagents together in a flask and hoping for the best usually doesn’t work. Either the reaction is just too slow to ever proceed, or there are dominant side-reactions leaving you with a complete mess of all kinds of compounds, just not the one you wanted. By adding a catalyst to a reaction mixture you solve both problems: the desired reaction pathway speeds up and this happens selectively, giving you in the best case just the one product you wanted.
However, the really beautiful and sustainable aspect of catalysis lies in another property. While the two above- mentioned effects (increasing the rate of the reaction, improving the selectivity of the reaction) could also be achieved by just a normal additive, a catalyst regenerates after each reaction cycle. To understand what that means, let’s have a look at a reaction:
Imagine you have 100 molecules of compound A and 100 molecules of compound B in your reaction container. The two compounds can react either to your desired product C or the undesired product D.
Adding an additive to the mixture gives you your product C exclusively. However, as a normal additive is consumed in the course of each reaction cycle, you need 100 molecules of additive. A catalyst by contrast regenerates itself after each cycle, which means you need just one little molecule to transform all molecules in the flask, one pair after another, into your product C.
Just imagine how dramatically this reduces waste!
These unique properties of catalysts have led chemists all around the world to work together on smarter and greener catalysts. Two different major routes should be distinguished here. The first one is finding good catalytic systems for challenging reactions. This is a lot of fun for chemistry nerds and the progress is astonishing, making transformations possible that look extremely unlikely on a piece of paper. The second one is more important to the general public by trying to make the catalysts cheaper and greener.
Why is this necessary?
The principle of catalysis sounds already really cheap and green. You need just one molecule of catalyst to transform hundreds of molecules into your product. A major difficulty lies in the nature of these catalysts, as their active centre is mainly based on rare metals such as Gold, Platinum, Palladium, Rhodium, Ruthenium or Iridium. Not really cheap and abundant materials, because of their general activity usually also not really compounds you want to release into nature. This is why some of the world’s best researchers are working on developing catalytic systems based on more abundant metals such as Copper, Cobalt, Zinc, Iron or even completely metal free.
In conclusion, catalysis makes difficult or even otherwise impossible reactions fast and reliable without producing extra waste as the catalyst is recycled after each reaction cycle. Catalysts nowadays are getting cheaper, greener and easier to make. And if you’re still wondering how to chat up that girl at the party: just ask a friend to be your catalyst!