(I once asked a class, "What is the most important chemical process in the world?" They guessed the Haber process, the Contact process, and electrolysis. Then I said, "You are all right — and you are all wrong. The most important chemical process is the one that makes the thing you need most right now. For a farmer, it is fertiliser. For a doctor, it is medicine. For a builder, it is cement. For a mother, it is clean water. Chemistry in industry is not about one process — it is about the thousands of processes that keep our world running. In this chapter, we are going to look at chemistry in industry and technology. We will learn how chemical processes are designed, scaled up, and optimised. We will learn about the raw materials, the reactions, the products, and the economics. And we will learn about the technologies that chemistry makes possible — from medicines to materials to energy. By the end, you will understand how chemistry builds the modern world. Let us begin.) Think about everything you use in a day. Your toothbrush. Your phone. Your clothes. Your food. Your medicine. Your transport. Every single one of these is a product of the chemical industry. The chemical industry is one of the largest and most important industries in the world. It transforms raw materials — oil, gas, minerals, water, air — into the thousands of products that modern life depends on. It employs millions of people. It generates trillions of dollars in revenue. And it is essential for almost every other industry, from agriculture to healthcare to construction to electronics. In this chapter, we are going to look at chemistry in industry and technology. We will learn about the principles of industrial chemistry — how processes are designed, scaled up, and optimised. We will look at key industrial processes, including the Haber process, the Contact process, and the Ostwald process. We will learn about chemical engineering — how chemists and engineers work together to turn laboratory reactions into industrial production. And we will explore the technologies that chemistry makes possible, from pharmaceuticals to smart materials to renewable energy. By the end, you will understand how chemistry builds the modern world — and the role you could play in it. Let us begin.
Industrial chemistry is the application of chemical principles to the large-scale production of chemicals and materials. It involves:
Some industrial processes are so important that they are studied in detail. Here are the three most important ones.
Reaction: N₂(g) + 3H₂(g) ⇌ 2NH₃(g) ΔH = −92 kJ/mol (exothermic)
Conditions:
Explanation of conditions:
Steps in the Haber process:
Reaction: 2SO₂(g) + O₂(g) ⇌ 2SO₃(g) ΔH = −196 kJ/mol (exothermic)
Conditions:
Steps:
Steps:
Designing an industrial process involves balancing many factors. Here are the most important ones.
| Factor | Considerations |
|---|---|
| Yield | Maximise the amount of product formed. This may involve adjusting temperature, pressure, and concentration, and removing products as they form. |
| Rate | Maximise the speed of the reaction. This may involve using a catalyst, increasing temperature, or increasing concentration. |
| Cost | Minimise the cost of raw materials, energy, equipment, and labour. This often involves compromises between yield and rate. |
| Safety | Ensure the process is safe for workers, the public, and the environment. This may involve using lower pressures or temperatures, or safer chemicals. |
| Environmental impact | Minimise waste, emissions, and energy use. This may involve recycling, using greener catalysts, or developing alternative processes. |
| Purity | Ensure the product meets the required specifications. This may involve additional purification steps. |
| Scale | Design the process to operate at the required scale. This may involve scaling up from laboratory to pilot plant to full production. |
Chemical engineering is the branch of engineering that deals with the design, construction, and operation of industrial chemical processes. Chemical engineers work alongside chemists to turn laboratory reactions into industrial production.
Key tasks of chemical engineers:
Scale-up is one of the most challenging aspects of chemical engineering. A reaction that works well in a small flask may behave completely differently in a large reactor.
Challenges of scale-up:
(Scale-up is where chemistry meets engineering. A reaction that takes a few seconds in a test tube may take hours in a reactor. A reaction that is safe in small quantities may be dangerous in large quantities. Chemical engineers have to think about all of this — and more. It is one of the most challenging and rewarding careers in science.)
Catalysts are essential in industry because they increase the rate of reactions, allowing processes to run at lower temperatures and pressures, saving energy and money.
| Process | Catalyst | Function |
|---|---|---|
| Haber process (ammonia) | Iron | Speeds up the reaction between N₂ and H₂. |
| Contact process (sulphuric acid) | Vanadium(V) oxide | Speeds up the oxidation of SO₂ to SO₃. |
| Ostwald process (nitric acid) | Platinum-rhodium | Speeds up the oxidation of NH₃ to NO. |
| Catalytic cracking (petroleum) | Zeolites | Breaks down large hydrocarbons into smaller, more useful ones. |
| Catalytic reforming (petroleum) | Platinum | Improves the octane rating of petrol. |
| Catalytic converters (vehicles) | Platinum, palladium, rhodium | Converts harmful gases (CO, NOₓ, hydrocarbons) into less harmful ones (CO₂, N₂, H₂O). |
| Polymerisation (plastics) | Ziegler-Natta catalysts | Controls the structure and properties of polymers. |
| Hydrogenation (food) | Nickel | Converts unsaturated fats to saturated fats. |
Catalyst poisoning: Some substances (called poisons) bind strongly to the catalyst and prevent it from working. For example, lead poisons the catalyst in a catalytic converter, and sulphur poisons the iron catalyst in the Haber process. This is why raw materials must be purified before they enter the reactor.
The chemical industry produces a vast range of products. Here are some of the most important categories.
Fertilisers provide plants with the nutrients they need to grow. The three main nutrients are nitrogen (N), phosphorus (P), and potassium (K).
| Fertiliser | Formula | Nutrient Content |
|---|---|---|
| Ammonium nitrate | NH₄NO₃ | Nitrogen (33–34%) |
| Ammonium sulphate | (NH₄)₂SO₄ | Nitrogen (21%) |
| Urea | CO(NH₂)₂ | Nitrogen (46%) |
| Superphosphate | Ca(H₂PO₄)₂ | Phosphorus |
| Potassium chloride | KCl | Potassium |
| NPK fertilisers | Mixtures | Nitrogen, phosphorus, and potassium |
The pharmaceutical industry produces medicines that prevent, treat, and cure disease. It is one of the most research-intensive industries in the world.
| Class | Example | Use |
|---|---|---|
| Analgesics | Paracetamol, aspirin | Relieve pain |
| Antibiotics | Penicillin, tetracycline | Treat bacterial infections |
| Antivirals | Aciclovir, oseltamivir | Treat viral infections |
| Antacids | Magnesium hydroxide | Neutralise stomach acid |
| Antihistamines | Diphenhydramine | Reduce allergic symptoms |
| Statins | Atorvastatin | Lower cholesterol |
| Antidepressants | Fluoxetine | Treat depression |
The polymer industry produces plastics, fibres, rubbers, and other materials. Polymers are used in everything from packaging to clothing to medical devices.
| Polymer | Monomer | Use |
|---|---|---|
| Polyethene | Ethene | Bags, bottles, pipes |
| Polypropene | Propene | Ropes, carpets, containers |
| PVC | Vinyl chloride | Pipes, window frames, cables |
| Polystyrene | Styrene | Packaging, disposable cups |
| PTFE (Teflon) | Tetrafluoroethene | Non-stick pans, waterproof clothing |
| PET | Ethylene glycol + terephthalic acid | Drinks bottles, polyester fabric |
| Nylon | Diamine + dicarboxylic acid | Clothing, ropes, carpets |
The chemical industry produces a wide range of materials with specialised properties.
| Material | Composition | Properties | Uses |
|---|---|---|---|
| Steel | Iron + carbon | Hard, strong | Construction, tools, machinery |
| Stainless steel | Iron + chromium + nickel | Corrosion-resistant | Cutlery, surgical instruments |
| Aluminium alloys | Aluminium + copper/magnesium | Light, strong | Aircraft, cars |
| Glass | Silica + sodium carbonate + limestone | Transparent, hard, chemically resistant | Windows, bottles, lenses |
| Cement | Calcium silicates and aluminates | Hardens when mixed with water | Construction |
| Ceramics | Clay minerals | Hard, heat-resistant, chemically inert | Pottery, tiles, insulators |
| Semiconductors | Silicon, germanium | Conduct electricity under certain conditions | Computer chips, solar cells |
Chemistry is the foundation of many modern technologies. Here are some of the most important.
The electronics industry depends on chemistry for the production of semiconductors, circuit boards, displays, and batteries.
Chemistry is central to the production, storage, and conversion of energy.
Chemistry is essential for the development of medicines, diagnostics, and medical devices.
Chemistry is essential for modern agriculture, from fertilisers and pesticides to soil testing and food preservation.
Chemistry is essential for the production of building materials.
Safety is a top priority in the chemical industry. Accidents can cause injuries, deaths, environmental damage, and financial losses.
Key safety measures:
Sustainability is increasingly important in the chemical industry. Companies are under pressure to reduce their environmental impact, and many are embracing green chemistry principles.
Strategies for sustainable industrial chemistry:
(The chemical industry is often criticised for its environmental impact — and rightly so. But it is also one of the industries that is most actively working to become sustainable. The next generation of chemical engineers and chemists will be the ones who make it happen. Maybe you will be one of them.)
Industrial chemistry offers many exciting career paths:
The chemical industry is constantly evolving. Some of the most exciting trends include:
| Trend | Description |
|---|---|
| Green chemistry | Designing processes and products that are sustainable and environmentally friendly. |
| Digitalisation | Using sensors, data analytics, and artificial intelligence to optimise processes. |
| Biotechnology | Using enzymes and microorganisms to produce chemicals. |
| Nanotechnology | Engineering materials at the molecular scale for use in medicine, electronics, and energy. |
| Circular economy | Designing products and processes so that materials are reused and recycled. |
| Carbon capture and utilisation | Using CO₂ as a feedstock for making chemicals and fuels. |
| Renewable energy | Using solar, wind, and other renewable sources to power chemical processes. |
Question: Explain why the Haber process uses a temperature of about 450°C and a pressure of about 200 atmospheres.
Solution: The forward reaction is exothermic, so lower temperatures would give a higher yield. But lower temperatures also slow the reaction. 450°C is a compromise — a reasonable yield at a reasonable rate. The forward reaction produces fewer moles of gas (4 → 2), so high pressure favours the formation of ammonia. 200 atm is a compromise between yield and cost — higher pressures would increase the yield but require more expensive equipment and energy.
Question: Write the equations for the main steps of the Contact process.
Solution:
Step 1: S + O₂ → SO₂
Step 2: 2SO₂ + O₂ ⇌ 2SO₃ (V₂O₅ catalyst, 450°C, 1–2 atm)
Step 3: SO₃ + H₂SO₄ → H₂S₂O₇ (oleum)
Step 4: H₂S₂O₇ + H₂O → 2H₂SO₄
Question: Describe the steps in the Ostwald process for the manufacture of nitric acid.
Solution:
Step 1: 4NH₃ + 5O₂ → 4NO + 6H₂O (Pt-Rh catalyst, 900°C)
Step 2: 2NO + O₂ → 2NO₂
Step 3: 3NO₂ + H₂O → 2HNO₃ + NO (NO is recycled)
Question: Explain why a chemical engineer might choose to run a reaction at a lower temperature, even if it gives a lower yield.
Solution: A chemical engineer might choose a lower temperature for several reasons: to save energy, to reduce the risk of side reactions or decomposition, to extend the life of the catalyst, or to reduce safety risks. In some cases, a lower yield at a lower temperature may be more economical if the energy savings and reduced by-products outweigh the loss in yield. Industrial processes are designed to optimise overall profitability, not just yield.
1. What is industrial chemistry?
Industrial chemistry is the application of chemical principles to the large-scale production of chemicals and materials.
2. State the conditions used in the Haber process.
About 450°C, 200 atmospheres, with an iron catalyst.
3. What is the catalyst used in the Contact process?
Vanadium(V) oxide (V₂O₅).
4. Describe the steps in the Ostwald process.
Step 1: 4NH₃ + 5O₂ → 4NO + 6H₂O (Pt-Rh catalyst, 900°C). Step 2: 2NO + O₂ → 2NO₂. Step 3: 3NO₂ + H₂O → 2HNO₃ + NO.
5. State three factors that affect the design of an industrial process.
Any three of: yield, rate, cost, safety, environmental impact, purity, scale.
6. What is scale-up and why is it challenging?
Scale-up is the process of increasing the size of a chemical process from laboratory to industrial scale. It is challenging because heat transfer, mixing, pressure, safety, and cost all become more difficult at larger scales.
7. State two strategies for sustainable industrial chemistry.
Any two of: using renewable feedstocks; developing greener catalysts; reducing energy use; minimising waste; using safer solvents; designing for degradation; life cycle analysis.
Question 1 [10 marks]
(a) Describe the Haber process, including the equation and conditions. [5]
(b) Explain why the temperature and pressure used are compromises. [3]
(c) State one use of ammonia. [2]
(a) Nitrogen and hydrogen are mixed in a 1:3 ratio and passed over an iron catalyst at 450°C and 200 atm. Equation: N₂ + 3H₂ ⇌ 2NH₃ (exothermic). About 15–20% of the gases react. Ammonia is liquefied and removed; unreacted gases are recycled. (5 marks: 1 for reactants, 1 for equation, 1 for catalyst, 1 for temperature, 1 for pressure.)
(b) Lower temperatures would give a higher yield (since the reaction is exothermic), but the reaction would be too slow. Higher pressures would also give a higher yield (fewer moles of gas on the product side), but the equipment would be more expensive. So 450°C and 200 atm are compromises between yield, rate, and cost. (3 marks: 1 for temperature explanation, 1 for pressure explanation, 1 for compromise.)
(c) Any one of: making fertilisers, making nitric acid, cleaning products, refrigeration, explosives. (2 marks: 1 for use, 1 for clarity.)
Question 2 [10 marks]
(a) Describe the Contact process for the manufacture of sulphuric acid, including the equation for the key step. [4]
(b) Explain the conditions used in the Contact process. [4]
(c) State two uses of sulphuric acid. [2]
(a) Sulphur is burned in air to form SO₂. SO₂ is purified, then oxidised to SO₃ using a vanadium(V) oxide catalyst at 450°C and 1–2 atm: 2SO₂ + O₂ ⇌ 2SO₃. SO₃ is dissolved in concentrated sulphuric acid to form oleum, which is then diluted with water to form sulphuric acid. (4 marks: 1 for SO₂ production, 1 for equation, 1 for catalyst, 1 for oleum/dilution.)
(b) Temperature of about 450°C is a compromise — lower temperatures give a higher yield (exothermic) but the rate would be too slow. Pressure of 1–2 atm is used because the yield is already high at low pressure; higher pressure is not worth the extra cost. Vanadium(V) oxide is used as a catalyst to speed up the reaction. SO₃ is removed continuously to shift equilibrium to the right. (4 marks: 1 for temperature, 1 for pressure, 1 for catalyst, 1 for removal of SO₃.)
(c) Any two of: making fertilisers, car batteries, detergents, dyes, metal processing, petroleum refining. (2 marks: 1 for each.)
Question 3 [10 marks]
(a) Describe the role of chemical engineers in industrial chemistry. [4]
(b) Explain why scale-up is challenging. [4]
(c) State two strategies for sustainable industrial chemistry. [2]
(a) Chemical engineers design, construct, and operate industrial chemical processes. They work on process design, scale-up, process control, safety analysis, economic analysis, and environmental analysis. They work alongside chemists to turn laboratory reactions into industrial production. (4 marks: 1 for each of four roles.)
(b) Scale-up is challenging because heat transfer, mixing, pressure, safety, and cost all become more difficult at larger scales. In a large reactor, it is harder to remove or supply heat evenly, harder to mix reactants evenly, and more expensive to build equipment that can withstand high pressures. The consequences of accidents are also much greater at industrial scale. (4 marks: 1 for each of four challenges.)
(c) Any two of: using renewable feedstocks; developing greener catalysts; reducing energy use; minimising waste; using safer solvents; designing for degradation; life cycle analysis. (2 marks: 1 for each.)
Challenge 1: Explain why the Haber process is considered one of the most important inventions in human history.
The Haber process is considered one of the most important inventions in human history because it made it possible to produce ammonia on an industrial scale, which in turn made it possible to produce nitrogen-based fertilisers. Before the Haber process, farmers relied on natural sources of nitrogen (manure, crop rotation, and nitrogen-fixing bacteria), which were not enough to support large populations. The Haber process allowed us to take nitrogen from the air and turn it into fertiliser, dramatically increasing crop yields. Today, it is estimated that nearly half the world's population is fed by food grown with fertilisers made possible by the Haber process. Without it, billions of people would not have enough to eat. It is a perfect example of how chemistry can change the world.
Challenge 2: Explain why industrial processes are not always run at the conditions that give the highest yield.
Industrial processes are not always run at the conditions that give the highest yield because yield is only one of several factors that determine the profitability and practicality of a process. Other factors include rate, cost, safety, and environmental impact. For example, a reaction might have a higher yield at a lower temperature, but the rate might be too slow to be practical. Or a reaction might have a higher yield at a higher pressure, but the equipment required to withstand that pressure might be too expensive. Or a reaction might produce more product at a higher temperature, but also produce more unwanted by-products or pose a greater safety risk. Industrial processes are designed to optimise overall performance — balancing yield, rate, cost, safety, and environmental impact. Sometimes, a lower yield at a lower cost is more profitable than a higher yield at a higher cost.
Challenge 3: Explain how chemistry contributes to the development of new technologies in medicine, energy, and electronics.
Chemistry contributes to new technologies in many ways. In medicine, chemists design and synthesise new drug molecules, develop drug delivery systems (like nanoparticles and liposomes), create diagnostic tests, and make biocompatible materials for implants and prosthetics. In energy, chemists develop solar cells, batteries, fuel cells, and catalysts for renewable energy production and storage. They also work on carbon capture and utilisation technologies. In electronics, chemists purify and dope semiconductors, develop liquid crystals and OLEDs for displays, create conductive polymers and nanomaterials, and design new materials for faster, smaller, and more efficient devices. In each case, chemistry provides the fundamental understanding of materials and reactions that makes new technologies possible. Without chemistry, these technologies would not exist.
"Chemistry in industry is not just about making things — it is about making things better, safer, and more sustainably. Now you understand how chemistry builds the modern world."
