Tie sustainable industry into your chemistry topics

In a broad and balanced science education students should discuss and evaluate the impact of scientific and technological development on society, the economy and the environment. Students will come across many contexts in their learning that allow them to consider how chemistry contributes both positively and negatively. Key contexts include extracting resources from the environment (fossil fuels, minerals and natural materials), processing resources (petrochemicals, air products and metals) and recycling/reusing materials (metals, plastics and wastewater).

This article is part of the Sustainability in chemistry series, developed to help you integrate the UN’s sustainable development goals into your teaching of chemistry. It supports Goal 9: build resilient infrastructure, promote inclusive and sustainable industrialisation and foster innovation.

Reaction kinetics and equilibrium are key to understanding and improving industrial processes, which fits well with goal 9: build resilient infrastructure, promote inclusive and sustainable industrialisation and foster innovation. Factors affecting the rate of chemical reactions directly contribute to process yields and energy demand, which relates to greenhouse gas emissions from burning fossil fuels. This links to the world’s renewable energy capacity and investment, which has seen striking increases in the last decade – the UN reports an increase in capacity of 12% from 2018–2019 alone.

Put it in context

Industrial processes are energy intensive and can cause pollution. Many industrial reactions are carried out at high temperatures: production of iron in blast furnaces (>800°C), extraction of aluminium in electrolysis cells (>900°C) and fractional distillation of crude oil (>300°C).

Energy production has been shifting towards renewable sources over the last decade. Wind and solar power capacities increase year on year. However, both rely on elements that can be in short supply and are sourced from countries that hold industrial monopolies where there are geopolitical tensions.

Energy production from fossil fuels is a significant contributor to climate change through release of carbon dioxide (CO₂). Migration to renewable energy sources will decrease the amount of new CO₂ released per year. However, atmospheric levels need to be reduced to mitigate the worst consequences of climate change. Carbon capture and storage seeks to remove CO₂ from the atmosphere and store it permanently in, for example, depleted oil fields.

Energy demand and pollution can be reduced using catalysts that decrease the reaction temperature. Catalysts provide alternative reaction pathways with lower energy activation energies, so reactions can occur at lower temperatures. We can design catalysts to increase the specificity of reactions, minimising the production of unwanted side-products.

Put it into practice

Ask your 16–18 students to research catalysts and reaction conditions and present their findings. Give them the opportunity to select a reaction they find particularly interesting and the freedom to choose their communication method. This will give them an authentic insight into how scientists work. A good starting point is the Essential Chemical Industry website, which has clear and accessible descriptions of general materials, such as biofuels and nanomaterials, and basic chemicals, such as ethanol and hydrogen. Download an outline information grid and notes on extending the activity with presentations.

International company Johnson Matthey provide a cutting-edge industrial context and are actively engaged with the UN’s sustainable development goals. They work on a wide range of catalytic processes from the production of syngas from municipal waste to producing catalytic converters to reduce direct air pollution from fossil fuel combustion engines. The Royal Society of Chemistry ran a campaign in 2019 on the importance of recovering and recycling rare elements. Students will find further interesting contexts to draw on, for example the elements in a mobile phone.

Introduce a quantitative chemistry aspect to your 16–18 students’ research. Ask them to calculate the atom economies of the processes they are investigating. They can look at the co-products of the reactions and whether they can be used in other industrial processes or whether they are waste. For example, thermal cracking of hydrocarbons can approach 100% atom economy as the alkane products are used in fuels and the alkene products used as feedstock for the polymer industry.

For a practical element, students could investigate the use of green alternatives to the commonly used reagents for organic synthesis. Oxidation of alcohols is commonly carried out using reagents such as acidified potassium dichromate. This reagent is hazardous to health and requires very careful handling. Fenton’s reagent, a mixture of iron(II) compounds with hydrogen peroxide, is a greener alternative.