Green chemistry aims to minimise the environmental impact of chemical products and chemical manufacturing. It’s applied across the lifecycle of a product, from initial design through to disposal.
Many manufacturing methods and chemical applications, such as pesticides, can have a harmful effect on the environment. Some hazardous chemicals and heavy metals, like mercury, are also biologically magnified through the food chain, which can lead to serious illness in secondary consumers. For example, when biologically magnified, the chemical compound DDT can cause cancers in humans.
Green chemistry aims to reduce these detrimental effects by taking a more environmentally-friendly approach to chemical products and chemical manufacturing.
In this post:
Definition of Green Chemistry
Green chemistry primarily focuses on designing chemical products and chemical manufacturing processes that contain zero or minimal dangerous substances. The main aim is to reduce or eliminate environmental and health hazards in chemical manufacturing and related processes, such as energy production.
Green chemistry covers the entire lifecycle of a chemical product. The various stages of a chemical product include:
- Design or formulation of the chemical
- Mass production of the chemical product
- Use or application of the chemical product
- Disposal or elimination of the chemical product
Green chemistry takes a practical approach to applying innovative solutions to environmental problems. It looks for effective ways to reduce hazardous substances and pollution by minimising the production of pollutants, and designing chemicals and processes that produce fewer harmful byproducts or waste.
Green chemistry is related to environmental science, but it’s not a distinct branch of chemistry. Rather, it’s a philosophy that’s applied to all aspects of chemistry.
What Are the Goals of Green Chemistry?
The main goals of green chemistry are to:
- Optimise available resources to develop better methods in the various stages of the lifespan of chemical products
- Reduce hazardous byproducts in the preparation and handling of chemicals, thereby lowering the detrimental impact on the environment
- Find alternatives to toxic reagents and chemical products that have similar properties
- Use efficient and renewable energy sources in manufacturing chemical products
- Manufacture chemical products that have zero or very low toxicity, thus minimising the health and environmental risks
- Reduce costs by streamlining the chemical manufacturing process
What Are the 12 Principles of Green Chemistry?
The majority of the concepts, goals, and core principles of green chemistry are derived from the Federal Pollution Prevention Act of 1990 in the United States. Many industrialised countries have similar legislation that follows the 12 principles of green chemistry.
The 12 principles of green chemistry were developed by Paul Anastas and John Charles Warner in 1991. Anastas is an organic chemist who worked in the Office of Pollution Prevention and Toxins at the EPA, while Warner is a chemist, entrepreneur, and educator.
The 12 principles are:
- Prevent waste – the design or formulation of chemicals should have zero or minimal toxic byproducts.
- Maximise atom economy – the goal here is to minimise the total number of wasted atoms in the process of synthesising a chemical product, either in the laboratory or in industry.
- Less hazardous chemical synthesis – as much as possible, the synthesis and processes involved in chemical manufacturing should be non-hazardous.
- Design chemical products that are safe – chemical products and their intermediate byproducts must have very little or zero toxicity.
- Use safe solvents – hazardous reagents and other chemicals must be avoided and safer alternatives should be used instead.
- Increase energy efficiency – chemical reactions and processes should ideally take place at normal room temperature and normal atmospheric pressure to conserve energy.
- Use renewable raw materials – starting materials, otherwise known as feedstocks, must be renewable, such as those from agricultural products or the waste products of other chemical manufacturing processes. Non-renewable sources like fossil fuels should be avoided.
- Discourage the use of chemical derivatives – chemical derivatives require additional reagents and they produce more waste products.
- Use catalysts rather than stoichiometric reagents – catalysts have minimal waste byproducts and are only used in small amounts. In comparison, large amounts of stoichiometric reagents are required and they’re only used once.
- Produce chemicals that degrade easily after use – biodegradable chemicals and chemicals that break down easily or become inert have a low impact on the environment and do not accumulate in biological systems.
- Real-time analysis of chemicals – chemicals must be monitored and analysed in real-time during the manufacturing process. This means hazardous byproducts can be eliminated immediately when they’re detected.
- Reduce or minimise the risks of accidents – chemicals must be formulated in such a way that minimises the risk of accidents like explosions and leaks.
How Does Green Chemistry Save the Environment?
As shown above, green chemistry saves the environment in several ways. These 12 principles can be classified into two main categories – reducing risk and minimising the environmental impact.
For example, designing chemicals and manufacturing processes that have low or zero waste byproducts can help to prevent possible toxic effects and contamination. However, it’s not only about sustainability; cost-effectiveness is an important consideration too.
What is Atom Economy in Green Chemistry?
Atom efficiency is part of the 12 principles of green chemistry. It refers to the degree of efficiency by which a chemical process converts raw materials into the desired products. High efficiency means few atoms are wasted in the process. This efficiency can be expressed in terms of a percentage of conversion.
How to Calculate the Atom Economy in Green Chemistry
You can calculate the atom economy of a chemical manufacturing process by dividing the total mass of the desired products by the total mass of all the products. Take note that “desired” products must be emphasised here. You should only include in the computation the mass of the desired products. The ratio can then be multiplied by 100% to get the efficiency percentage.
How Important is Green Chemistry?
Green chemistry is important in the various stages of the lifespan of a chemical product, from formulation right through to disposal.
Minimising or, better still, eliminating the harmful effects of chemical products brings many benefits. From cleaner air and water to safer consumer products, reduced landfill and healthier ecosystems, green chemistry is vital to creating a more sustainable and environmentally-friendly future.
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