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The path that products take to get onto store shelves doesn’t always leave the best impact on the environment. But with green chemistry, chemists have found ways to make the production of some items safer for both people and the planet.

Hosted by: Michael Aranda

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[♪ INTRO].

We all want the things that we  use every day to be greener. Unfortunately, even if something feels  really green in the hands of us consumers, the path it took to get to us… might not be.

It might require hazardous chemicals  to make, or generate a lot of waste. Or be harmful to people actually making  it as well as to the environment. But it’s not like chemists don’t  care.

They want a greener world too. And they’re in a position  to do something about it. That’s the idea behind green chemistry, an approach chemists have been  working on since the 1990s to make chemistry safer at every step  of the way — not just for consumers.

Green chemistry is about creating  new technologies and processes that will keep chemicals  financially viable and effective, but will also make sure they’re  not harmful to the environment or to the people who make them and use them. And based on its guiding  principle of “benign by design,” green chemistry has already done  a lot of good for the world. So let’s take a look at five everyday things that green chemistry has made  safer and, well, greener.

It turns out that like money,  decaf coffee doesn’t grow on trees. You start with regular coffee,  and take the caffeine out. Technically, all you need to  decaffeinate coffee is water.

Water is cycled through vats  of green, unroasted beans, picking up some of the caffeine on the way. Then, the caffeine-infused water goes through  a charcoal filter that removes some of the caffeine, allowing the water to  dissolve more, and the cycle repeats. You might say that this process  already sounds pretty green, since it’s mostly based on good ol’ H2O.

That’s true, but the problem is  that along with the caffeine, it also can also remove a lot of the  compounds responsible for flavor, resulting in decaf that’s a little... bleh. See, water is a very good solvent… too good. So a lot of substances, like  coffee flavor compounds, can easily dissolve in it and hitch  a ride out of the coffee bean.

So to improve on the process, decaf  makers turned to less versatile solvents, usually methylene chloride or ethyl acetate. These certainly help preserve the coffee’s  flavor, but concerns have been raised about their safety — especially  in the case of methylene chloride. These solvents are common ingredients  in things like degreasers or nail polish removers, and can  be toxic when not handled right.

For example, methylene chloride  can cause respiratory damage if you inhale too much. But green chemistry aims to  improve chemical safety for people as well as reducing environmental impact. And it has a solution that’s safer  for coffee makers and drinkers alike.

It’s supercritical CO2. The “supercritical” part doesn’t mean that  it’s a chemical that’s really hard to please. The name refers to the critical  point, where a substance is between two states: neither liquid, nor gas.

When carbon dioxide becomes supercritical,  it turns into an amazing solvent. Like a gas, it can easily penetrate  all the nooks and crannies of something like a  caffeine-packed green coffee bean. And like a liquid, it can easily pick  up the caffeine and spirit it away.

It’s also much better at that than  the solvents that came before. It can extract more of the caffeine, around 98%. And it’s much more of a selective caffeine sniper, so it takes it away without  destroying that rich coffee flavor.

It’s also not toxic, but you may be  wondering how using carbon dioxide could really be all that green. After all, CO2 in the atmosphere is  what’s responsible for climate change. But in a decaffeination plant, the  CO2 can be reused multiple times.

And since it’s extracted from  the air in the first place, it’s not going to increase the net amount  of carbon dioxide in the atmosphere, even if some of it accidentally gets released. So thanks to green chemistry,  you can sip your decaf without worrying about harming the environment. As long as you remember to recycle the cup.

Catalysts are substances that increase  the rate of chemical reactions. And they can increase it by a lot. Something that takes a fraction of  a second to make with a catalyst could take years to produce without it.

The pharmaceutical industry is in the business of using chemical reactions to  produce complex molecules, so they really could not exist without catalysts. Those catalysts are often made from heavy metals, or other substances with  significant environmental impacts. Thankfully, nature has provided  us with a ready-made solution.

Once we’ve made appropriate tweaks, of course. See, living cells happen to be  experts at making catalysts. They’re called enzymes, and they  facilitate the many chemical reactions that keep us alive.

Enzymes are made of protein, encoded by DNA. Which means they’re biodegradable,  and light on heavy metals. And the pharmaceutical industry is starting  to adopt them as greener catalysts.

Sitagliptin is one of the most commonly  used type 2 diabetes medications. Traditionally, the process of producing  the drug required energy-heavy, high-pressure equipment, as  well as rhodium catalysts, which are highly toxic and can cause cancer. In 2009, two companies figured  that all of that could be helped by the use of transaminases.

Transaminases are enzymes  that, among other things, help our cells build the  proteins that we’re made of. In the drug, they instead make a chemical change to help build the final desired molecule. Naturally occurring transaminases  weren’t efficient enough to replace the rhodium catalysts.

But scientists used genetic engineering  to create a beefed-up transaminase that was 25,000 times more efficient  than the transaminases found in our body. That allowed the makers of sitagliptin  to replace the energy-guzzling high-pressure equipment and toxic catalysts  with a simplified, greener process. Another example is the widely used  cholesterol-buster simvastatin.

This medication is derived from a fungus,  but the process necessary to do that involved the use of large  amounts of hazardous chemicals. Like n-butyllithium, which...sort of turns the air into an explosive when handled improperly. It also generated a lot of harmful waste.

But just like with sitagliptin,  researchers tried to find naturally occurring enzymes  that could make things better. And what they ended up going with was a  kind of acyltransferase, an enzyme which, among other things, helps our  cells process chemical signals. The researchers bioengineered the enzyme to jack up its efficiency as a  catalyst by about 1,000 times.

That allowed them to greatly  reduce waste and cut out multiple dangerous chemicals, making  the whole process much greener. Your laundry can also be greener! And not only when your whites  get a new springtime sheen thanks to that stray Incredible Hulk sock.

We’re talking about cold water detergents – which get your laundry clean at lower  temperatures than traditional ones. Which means you’re doing the environment a favor by using less electricity for the wash cycle. But thanks to green chemistry,  cold water detergents are also more environmentally friendly even before  you feed them into your washing machine.

Most laundry detergents are  derived from petroleum – you know, that stuff that’s also a fossil fuel. But things changed with the discovery  of metathesis, a new approach to chemical synthesis that got its creators  the 2005 Nobel Prize in chemistry. To develop greener detergents, a company called Elevance used metathesis  to break apart plant-derived oils, then assembled the resulting  building blocks into novel chemicals.

That process cuts energy use and  greenhouse gas emissions by half when compared with detergents made from petroleum. And reduces demand for petroleum itself. So cold water detergents are a double whammy.

They’re helping you save energy  and cut your carbon footprint. And by cutting out petroleum  and reducing energy usage, chemical manufacturers are making them  greener before they ever get to you. In the late 1960s, firefighters  started adding foaming agents to water in order to make it better at fighting fires.

These are basically chemicals  that turn water into foam. Foamy water is better at absorbing heat,  and it doesn’t evaporate as quickly, which means it will easily seep into  hot spots that could restart the fire. And because it stays around for a while, it forms a sort of blanket that cuts off  the oxygen needed to keep a fire going.

Initially, firefighting foams  used fluorinated surfactants, which are also found in things  like heat-resistant packaging. These were useful for any kind of big fire  — like building fires or forest fires. But it turned out that these  fluorine-based foaming agents easily penetrated into groundwater  and would stay there for decades.

They would also build up in the bodies of  aquatic animals, not to mention us humans, causing thyroid problems  and several types of cancer. So many governments have  worked to phase out fluorine — but it’s been hard to find a substitute  that’s anywhere near as effective. However, one major producer  of firefighting chemicals has come up with a greener alternative  that still works to fight fires.

This new firefighting foam  doesn’t contain any fluoride. Instead, it uses polysaccharides, which  are basically chains of sugar molecules. This greener formula is better at quashing  fires than traditional firefighting foams, and it completely breaks down within 42 days, instead of sticking around to cause problems.

There’s a lot we can learn from a DNA  sample. But small amounts of DNA are often not enough for our technology  to read out and interpret. So for everything from forensic analyses  to testing for viral infections, we usually start by turning a little DNA  into a lot — using a technology called PCR.

PCR, or polymerase chain reaction, is a way to chemically multiply the  DNA in a sample that we want to test. In theory, it produces billions of  copies from just a single molecule. And allows our devices to easily analyze  it and do a lot of cool stuff with it, like genome mapping or paternity testing.

But it’s not just for shocking  reveals on talk shows. Many of us, or those we  know, have taken a PCR test — because it’s one of the  technologies that makes it possible to diagnose someone with an  active COVID-19 infection. So this technology is a workhorse of  both molecular biology and public health.

Which makes it unfortunate that it comes  with a particular environmental drawback. PCR needs deoxynucleotide  triphosphates, or dNTPs, in the mix. dNTPs are simply the building blocks that those billions of copies of our  DNA fragment will be assembled from. But making these dNTPs requires the  use of multiple hazardous chemicals, like the highly corrosive zinc  chloride — or methylene chloride, the bane of caffeine extraction.

However, the biotech companies  that supply the ingredients for PCR are working to change that. One company uses a new green synthesis process that cuts down on those nasty solvents by 95%, and it also creates ten times less chemical  waste as a byproduct of making dNTPs. We’re definitely not going to stop  doing PCR — but this way, every year, the environment gets hit with around  700,000 kilograms less of toxic waste from just a single production plant.

There’s still a lot of  progress to be made in ensuring the chemical industry is as  safe and as green as it can be. Technically, chemical manufacturers  aren’t yet required to prove that the space-age plastic in your new smartphone is not going to make you grow a new nose, or make all the birds in your yard drop dead, until you complain that it did. Basically, green chemistry is  something we rarely hear about: activism within the scientific  community to make their own field safer, because the stuff they produce affects  everyone, from firefighters to decaf makers.

And green chemistry principles  are now being adopted by key players in the chemical  industry all over the world. Which is going to make things in our  everyday lives just a little bit safer — for us and the planet. Thanks for watching this episode of SciShow, and thanks as always to our patrons  for helping to make it happen.

We’d love to buy you a coffee and say  thanks — doesn’t have to be decaf — but instead we’ve got neat perks, like  bloopers and behind-the-scenes photos. If you’d like to get involved,  check out patreon.com/scishow. [♪ OUTRO] .