Green Chemistry 101

Do you recycle? Compost? Turn off the lights when you leave a room? If so, you’re practicing environmental sustainability. You’re recognizing that our planet has limited resources, and you’re supporting its long-term health.

Chemists design all kinds of products, including plastics, pesticides and pharmaceuticals. Historically, when chemists have designed products, they would focus on the product’s usefulness. They didn’t necessarily think about sustainability. In fact, a lot of these products and the processes used to make have actually turned out to be harmful for the environment! So have the processes used to make them. That’s why the field of green chemistry has been growing over the past 30 years.

Chemists use green chemistry to look at the sustainability and environmental impacts of manufactured chemical products and processes. Green chemists think about a chemical’s impact from the laboratory, to the disposal site, to the environment where it is released. One way they can evaluate these impacts is with the 12 Principles of Green Chemistry. 

Let’s look at three of these principles in detail.

The Prevention of Waste 

This principle actually applies to many aspects of life, both in and outside of the laboratory. For example, it’s the first rule of the Three R’s: reduce. It’s important to dispose of waste properly. But it’s even better to reduce the amount of waste being produced in the first place. 

You might apply this principle by trying to produce less garbage at home. Chemists apply this principle by trying to produce less chemical waste.

You might not think of your car as something that produces waste, but it does. Inside a car’s engine, fuel and oxygen from the air undergo a chemical reaction called combustion. The combustion reaction produces the energy needed for the car to move. But it also produces some harmful byproducts. For example, combustion produces carbon monoxide (CO), which is poisonous. It also produces volatile organic compounds (VOCs), nitrogen oxides (NO_x), and unburnt hydrocarbons (HC). All of these contribute to smog. Too much smog in the environment can give people respiratory illnesses.

Luckily, cars contain a piece of technology that helps prevent the production of harmful chemicals. It’s called a catalytic converter. While the car is running, a catalytic converter chemically changes these pollutants into less harmful molecules before they’re released from the car’s tailpipe. Examples of these less harmful molecules are oxygen (O₂), nitrogen (N₂), carbon dioxide (CO₂), and water (H₂O).  

Did you know?

There are many ways that air pollution can actually cost people money. For example, people might miss work or need to buy medicine if they get sick from pollution. If they own a home in a polluted area, that home might become worth less money over time. In fact, researchers estimated that air pollution cost Canadians over $36 billion in 2015! 

Atom Economy 

Imagine you are making cookies and you measure out two cups of flour. You only end up using one cup of flour to make the cookies, so you throw out the other cup. That would be very wasteful!

Sadly, this type of waste can happen when chemists make various products through chemical reactions. Green chemists aim to reduce this waste by looking at atom economy. Atom economy asks the questions, “What percent of atoms from the reactants are incorporated into the product? What percent of atoms are wasted?” 

For example, the synthesis reaction that occurs during photosynthesis in plants leads to two products: glucose (C₆H₁₂O₆) and oxygen gas (O₂). If the glucose were the desired product, then the oxygen gas would be considered a wasted product. 

Ideally, products should have a high atom economy. Most of the ingredients added during a chemical process should be used to make the final product.

You might have an example of green chemistry in your medicine cabinet: ibuprofen, the active ingredient in Advil and Motrin. The original method for making ibuprofen was wasteful and inefficient. Of the atoms used to make the product, only 40% made it into the final product. In the 1990s, the manufacturer developed a new process that incorporated a few of the principles of green chemistry. Since the changes, 77% now make it into the final product!  Changes like this earned the manufacturer a Green Chemistry Challenge Award in the United States in 1997. 

Catalytic Ingredients

A catalyst is a substance that helps a chemical reaction happen or makes it go faster. Catalysts can lead to reactions that produce less waste or have a greater atom economy.

Take the example of the catalytic converter that can be found in a car. As its name suggests, the converter contains a catalyst. The catalyst causes the reaction that converts some of those toxic gases into less harmful ones.

 As an added bonus, catalysts aren’t used up in a reaction! That means they can be continually reused without being replaced.

Did you know?

Vehicles with Diesel engines use different catalytic converters than vehicles with gasoline engines.

The principles of green chemistry in industry and at home 

Green chemistry principles are important. They help chemists make some of the products you use every day less harmful to the environment. They can also help manufacturers save money. That’s because green chemistry means more efficient processes with less wasted material, less energy used, and less hazardous waste to clean up!

You may not be a green chemist yourself. But you can still apply sustainable green chemistry practices in your life! For example:

• Reduce the waste you produce by recycling or composting when possible
• Try to choose products that are made using green chemistry practices
• Dispose of harmful waste in a proper way (for example: recycle batteries and electronics at designated locations, and return unused medicine to your pharmacy instead of pouring it down the drain)

Finally, you can make a big impact when you go shopping. Buy products that don’t have a lot of packaging, are less harmful to the environment, and are made with sustainability in mind!

Did you know?

Electric cars are an example of a product made with sustainability in mind. More and more Canadians are buying them. In fact, the Government of British Columbia has announced that all vehicles sold there after 2040 must produce zero emissions.