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September 2020 | Issue 01


What is Chemistry?

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The Role of a Chemist

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What is a Molecule?

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Reactions: How do they start?

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Making Molecules

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Molecules in Society: Plastic

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Molecules in Society: Agrochemicals

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Molecules in Society: The Pharmaceutical Industry

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Molecules at Home: A day in the life of Jo

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Sustainability

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How long does your rubbish live for?

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What is Green Chemistry?

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Using Catalysts in Late-Stage Functionalisation

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Illustrating C-H functionalisation with IKEA furniture

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C-H functionalisation EXPLAINED

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Photochemistry

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Electrochemistry

32

Puzzles

35

Glossary

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All matter is made up of atoms. An atom is the smallest piece of a chemical element. Elements are the fundamental ingredients that make up everything, they include hydrogen (H), carbon (C), sodium (Na), and iron (Fe) for example, as well as 114 others. Sometimes atoms of these elements are combined. and connected by chemical bonds to form molecules.

The lines in the drawing that connect the atoms are chemical bonds. These are strong connections holding the atoms together, and chemical reactions are the process by which the bonds in a molecule are made, broken, or rearranged.

=

Latia Luciferin (Displayed Formula)

Latia Luciferin (Skeletal Formula)

This molecule has the common name Latia luciferin. It is found in the freshwater snail Latia neritoides, which uses the molecule to make a luminescent slime that it emits when disturbed or attacked by a predator.

Molecules are often drawn in a skeletal formula. Carbon atoms are included as corners or kinks in the skeleton, and hydrogen atoms bonded to carbon are excluded. This makes the drawing much less cluttered.

Molecules found in animals and plants often inspire the development of pharmaceuticals and biologically-active targets. Compounds isolated from deep sea sponges, toxic plants, deadly bacteria and other natural sources have made their way into products we now use for medicinal and cosmetic purposes.

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Molecules are extremely small! The lengths of chemical bonds vary depending on the participating atoms, but a typical carbon-carbon bond is around 1.5 nanometres long. For reference, human hairs are 17,000180,000 nanometres wide.

A chemical reaction is denoted by an arrow. In this example, the enzyme luciferase breaks down latia luciferin in a reaction that produces light as a by-product.

Methyl Group

Formate Group

Double Bond

Chemists use functional groups to describe parts of molecules that behave in similar ways. This helps identify molecules that might have similar properties to other molecules or undergo similar chemical reactions.

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Reactions: How Do They Start?

A reaction is a process that involves changing a molecule s structure. • Bonds between atoms on molecule 1 and 2 are often broken and the pieces are reassembled to make molecule 3. • Energy is absorbed to break bo • Molecules must collide with ea Energy is is easier to achieve in liquid or • Specific changes require s often needed molecules. to initiate a •

reaction

• •

1

• •

Thermochemistry Light energy

Ofte •

2

• •

Electrochemistry

8

3

Smal avail numb Cont terms Heat (altho minim UV lig by th

Start and stop the reaction insta (by the flick of a switch) • One set-up can provide a vast energies by varying the potent Requires specific (often expen • • Requires specific (often expensiv that manlabs labs don t ha that man don t ha e. e. all solvents are compatible Not all solvents •areNot compatible with the equipmen •

Easy Gene doub in tem Risk o Time after equip


Molecule 1 + Molecule 2 Reactants (consumed)

onds. ch other to react, which gas state. pecific energy and

and cheap set up erally the reaction rate bles for every 10 °C rise mperature of explosions and energy waste use while the pment cools down.

Energy

Molecule 3

Atom

Product(s) (produced)

Heat, Light and Electricity are

energy sources and can vary the amount of energy they supply to a reaction:

Bond Molecule

1. Variable Temperature = Variable Energy 2. Variable Light Colour & Intensity = Variable Energy 3. Variable Potential & Current = Variable Energy

Microwave heating is a more sustainable alternative to a hotplate: Higher efficiency shown: less energy is required to reach a higher temperature.

LEDs and lasers are more efficient than incandescent lighting (white bulb): Less heat production and energy waste

n LED or Laser

illumination

ll, versatile and lable in a large ber of colours rolled exactly in s of energy and time is generated ough usually mal) ght can be absorbed he glass container.

antly

array of ial. sive) equipment e) equipment

ent.with the

Lab Set-up Glass container

• Glass withstands high temperatures. • Holds molecules, solvent and a stir bar. • Solvent and stir bar ensure efficient mixing, so molecules collide.

Clamps

• Securely hold the equipment

Bath

• Oil bath for efficient heating

Hotplate

• Temperature control; heat up the plate • Stir rate control; a magnet spins the stir bar

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From feedstocks to the flask: how does chemistry enrich society? Synthesis in Society The importance of chemicals to society is undeniable cancer-killing pharmaceuticals, cropdefending pesticides and even the OLEDs that illuminate many of our mobile phone screens are all the products of a series of complex chemical reactions. But what does it mean to make molecules? How do we turn simple feedstocks, such as hydrocarbons from crude oil, into complex substances such as drugs? And why are these processes important to the concept of sustainability? Read on to find out! Most people are familiar with the concept of a chemical reaction a process in which one substance is converted to another through a chemical change. Many might associate chemical reactions with little more than fizzes, bangs and pops from their experience playing with a Bunsen burner in high school but in reality, these are crucial and sophisticated tools in the creation of essential molecules for our society. Chemical synthesis is - put simply - the science of manipulating and ‘stitching together’ simpler molecules to make more complex ones. Chemical reactions are the means of making and breaking chemical bonds that allow us to transform a given substance into something else.. The simple chemicals that are glued together to form more complex compounds are often referred to as building blocks in organic chemistry. With this in mind, the synthesis of complex molecules can be analogised as a jigsaw puzzle of sorts: the puzzle pieces (building blocks) have to be put together in the right way (using the right reactions!) to complete the puzzle (make the right molecule!).

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Chemical Reac ion Ben ene Jo rne From Crude Oil to Paracetamol It can be difficult to imagine how the oily hydrocarbon liquids we extract from crude oil can be transformed into highly sophisticated, structurally-complex molecules such as drugs(of course, when we decide not to burn them for fuel!). To begin to illustrate how chemistry is used to transform simple feedstocks into more sophisticated substances, we can think about the synthesis of paracetamol: a widespread painkiller that everyone is familiar with and likely to have used at some point in their lives. The ultimate starting point for the synthesis of paracetamol is an organic substance called benzene, which is a clear, colourless liquidwellknown to every chemist due to its ubiquity in chemistry. Its molecular structure consists of a flat, hexagonal ring of six carbon atoms which are each bonded to a single hydrogen atom, and as such has the formula C6H6. It is produced on a massive (multi-billion kilo!) scale annually, mainly through a process called catalytic reforming in which a mixture of hydrocarbons from crude oil are heated to high temperatures with hydrogen gas over a metal catalyst. This substance is a crucial raw material for a whole host of more complex benzene-containing substances, which have widespread uses in dyes, agrochemicals and pharmaceuticals.


(continued...)

The Environmental Impact

The next stage of benzene’s journey from crude oil to paracetamol is the addition of what is referred to as an alcohol group an oxygen and a hydrogen atom which is attached to benzene’s carbon ring through a chemical reaction referred to as the cumene process. This new molecule is called phenol, and the alcohol group that was added completely changes its chemical properties. It is no longer a clear liquid like benzene it exists at room temperature as a white solid, and is one step closer to becoming paracetamol! Next, some more atoms must be added to the ring a nitrogen and two hydrogen atoms, known as an amine group. This requires us to subject our new phenol molecule to two further chemical reactions, which also happen to have fancy names nitration and reduction. We’ll leave out the grisly technical details, but these reactions involve some concentrated acid and iron powder. After adding both the amine and alcohol groups, the molecule we end up with is called aminophenol. This is one step away from paracetamol and serves as a key building block in the synthesis there’s just one more group of atoms to append. The final reaction glues on a few carbon, oxygen and hydrogen atoms to the amine group, transforming the amine into a new chemical group referred to as an amide. This final structure is the paracetamol molecule. Notice how the ring of carbon atoms that we originally obtained from crude oil the benzene ring accounts for a significant part of the structure of this molecule, despite the properties differing significantly from benzene itself (including being safe for ingestion!). Improving the sustainability and ‘green’ metrics of chemical synthesis encompasses many facets which will be discussed throughout this publication, but the source of our chemical feedstocks is one important area of consideration. The ultimate source of the carbon in many of the organic chemicals we produce to meet human needs is crude oil. This is, hpwever, a finite resource - and the search for alternatives is an important area of current research.

Chemistry does not always have the most pristine reputation when it comes to environmental impact. The massive human demand for chemicals such as cosmetics, drugs and plastics means that the industry has an outsized impact on the environment in which it operates. By necessity, due to the large volumes of solvent required for synthesis and the by-products generated in production, large-scale chemical processes create significant amounts of hazardous waste that can be harmful to the environment when not dealt with properly. Even when correctly disposed of, chemical waste is most often incinerated, which contributes to air pollution. Another major environmental issue associated with large-scale chemical synthesis is the energy requirements. A great deal of important chemical reactions do not happen spontaneously at room temperature, and require a significant input of energy in order to make them occur. This is most often achieved by simply heating the reaction mixture up, although this is highly energy-inefficient and can require large quantities of electricity when chemicals are manufactured on a large scale.

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Molecules in Society: Chemicals used for agriculture are known as agrochemicals, and have had massive impacts on the development of the modern world. These chemicals include fertilisers and pesticides used to aid crop growth, acidifying and liming agents used to maintain soil quality, and hormones and antibiotics used in the raising of livestock.

Fertilisers Fertilisers are nutrient-rich substances applied to crops to promote productivity. They contain elements like nitrogen, phosphorus and potassium which are essential for plant growth, and are taken up from the soil via plant roots. Fertilisers can be natural (such as manure, compost, or bone meal) or synthetic (such as ammonium phosphate and ammonium nitrate). A landmark discovery in agrochemical production was the Haber-Bosch process. Developed by Fritz Haber and Carl Bosch at the start of the 20th century, the process is used to convert nitrogen and hydrogen into ammonia. Naturally, microorganisms in the soil convert atmospheric nitrogen into forms that can be taken up by plants by a process called nitrogen fixation. Farmers typically need to supplement their crops with synthetically-produced ammonia in order for them to thrive, which is produced annually on a massive scale by the Haber-Bosch process. In the reactive form of ammonia, chemists are able to easily make nitrogen-based compounds and use them as fertilisers. The Haber-Bosch process is often cited as the cause of the orld s population explosion. Amazingly, it has been estimated that the orld s population would be almost halved if synthetic nnn fertilisers like those produced in 14

the Haber-Bosch process had not been invented.

Unfortunately, unforeseen consequences of the overuse of fertilisers have been realised. The leaching of fertiliser from farmland into bodies of water has led to disturbances in ecosystems, declining biodiversity and depreciating water quality. Approximately 40% of fertiliser nitrogen lost to the environment returns to the atmosphere in the form of nitrogen gas, and although this process seems inconsequential, the energy wasted in this process accounts for around 1% of the orld s global primary energy supply. Emissions of nitrogen-based pollutant gases have increased up to twenty times the natural rate in some regions of the world, in part due to overuse of nitrogen-based fertilisers.

Pesticides While fertilisers are used to encourage growth, pesticides are designed to prevent the growth of undesired species. The many uses of pesticides include crop and livestock protection, the deterrence of disease-carrying animals and nuisance organisms, and the protection of structures and areas of the environment. They can be biological agents such as bacteria, viruses or fungi, or chemical agents. Historically, substances including arsenic, mercury and lead have been used as pesticides, but today strict


regulations govern pesticide use. In the EU, compounds that are known to cause genetic or hormonal problems in humans are banned. Also banned are compounds that are persistent or bioaccumulative - these are chemical compounds that remain in the environment or are taken up by animals. Further up the food chain, these compounds may be consumed by humans. Pesticides that make their way to destinations other than their target area can impact the quality of animal habitats, pollute water, and contaminate soil.

Concerns over animal welfare and the distribution of hormones in food for human consumption have led to strict EU regulations on the use of certain hormones. While some hormones do make it into animal products, such as Bovine Somatotropin (bST) used to promote milk production, the concentrations of these chemicals in foods presents no significant risk to human health, and/or these hormones are destroyed in digestion and don reach the bloodstream.

Acidifying & Liming Agents

Antibiotics are substances that are active against bacteria. Much like in humans, antibiotics are used in cattle to treat and prevent bacterial diseases. When cattle get sick, they are separated from the rest of their herd, and if diagnosed with a bacterial infection or illness, may be prescribed a course of antibiotics by a vet. Records of the antibiotic doses are kept so that once the course of antibiotics is finished, the antibiotics have time to be fully broken down before milk or meat can he harvested from the animals. Animals like poultry and swine are raised in close proximity, and the potential for disease to spread is high. For this reason, many farmers of these animals simply add the antibiotic to the animal feed so that all animals remain healthy.

Another use of agrochemicals is in the acidifying and liming of soils. Different plants require different soil acidity to grow most efficiently, so farmers use acidifying and liming agents to change the pH of the soil to suit their crops needs. The pH scale is a measure of acidity, where 7.0 is designated as neutral, values below 7.0 are acidic, and values above 7.0 are basic. Soil pH can be affected by acidic precipitation, by gases or particles in the atmosphere, and by the application of fertilisers. To artificially acidify soil, sulfur compounds or acidic organic matter such as peat are dispersed onto the soil. More commonly, soil acidity needs to be reduced, by applying lime or other acid-neutralising minerals.

Hormones & Growth Agents Hormones are chemicals that are naturally produced in animals, including humans, to regulate their bodily functions. Although they are naturally produced in their livestock, farmers may give additional hormones to their animals to grow more efficiently or increase milk production. Plants also regulate their biology using hormones, and plant hormones have been used to encourage plant growth, to regulate plant breeding, to control ripening and to kill weeds.

Antibiotics

A major concern over antibiotics is the rise of antibiotic resistance, which has been highlighted as an issue in both humans and animals. When bacteria are regularly exposed to an antibiotic, bacterial mutations can arise that allow them to become resistant to it. Eventually the entire population will be resistant to the antibiotic, and the antibiotic will no longer be effective. The misuse of antibiotics has led to increased antimicrobial resistance, and has resulted in stricter regulations 15 over antibiotic use.


The Pharmaceutical Industry How can late-stage functionalisation improve the drug discovery process? Background The process of discovering, developing and marketing a new drug is extremely expensive, timeconsuming and fraught with pitfalls. The current average costs of developing a drug stand at around USD$2.6 billion, and the average time taken is six to seven years. New drugs must pass through four different phases of clinical trials; failure at any phase will terminate the dr g s development. Failure is often a killing blow for smaller biotech firms built around small-molecule therapeutics, as they are frequently unable to swallow the cost of a doomed clinical trial. But why is this process so resource-intensive? And why might advancements in late-stage functionalisation (LSF) benefit the drug discovery process? Read on to find out!

Often these compounds are prepared from scratch in lengthy synthetic procedures, consuming a huge amount of time and resources. 2) Modification and optimisation of the lead compound The lead compound is not necessarily the drug molecule that is chosen as the final structure. In order to improve its properties further and reduce any potential side effects, the structure is often further modified by creating derivatives. Like before, without new developments in LSF, each derivative to be tested often has to be synthesised from scratch, which is highly inefficient.

The Screening Process One of the most capital-intensive steps of the smallmolecule drug discovery cycle is the screening process, in which many thousands of potential molecules are tested for desired biological activity. This technique is referred to as high-throughput screening; massive libraries of promising compounds are tested for a desired interaction with a biological target. A number of shortlisted compounds are taken forward, and further whittled down until a lead compound is identified. There are two major chokepoints in this step that can benefit from more efficient chemical methodology: 1) The number of compounds required at the screening stage In order to maximise the chances of getting a hit (i.e. a promising molecule that may later be chosen as a lead compound), it is often necessary to screen a very large number of compounds. Many of these may be variations of a common structure with known pharmacological activity pertaining to the desired properties.

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From the bench to the clinic: a long and expensive journey!


Late-Stage Functionalisation to the Rescue! The spiralling costs of research and development are of major concern for large pharmaceutical companies, and new innovations that reduce some of the inherently resource-intensive aspects of the drug discovery process are highly welcome. The concept of late-stage functionalisation is one of the most significant practical innovations to emerge from organic chemistry research in recent times, especially due to the explosion of new reactions that can add in chemical groups to otherwise unreactive C-H bonds. Pharmaceutical companies that conduct in-house synthesis and screening are therefore interested in this concept as it addresses the two points mentioned previously: 1) Synthesis of compounds for screening: Synthesis of many variations of a particular compound is highly inefficient when done from scratch each time. Late-stage functionalisation allows a common intermediate compound to be modified directly, allowing the creation of many derivatives in a much more expedient manner. This could save a company huge amounts of time and money at the screening stage. 2) Optimisation of a lead compound: Like at the screening stage, LSF allows for easy modification of a compound of interest. This should drastically reduce the time it takes to generate chemical derivatives for further testing and pick out a perfected drug structure to be taken forward into clinical trials. The Future

Pharmaceutical companies are becoming increasingly interested in cutting-edge synthetic methods such as photoredox catalysis and electrosynthesis as efficient ways of making chemical compounds and their derivatives. Research efforts in these areas are only likely to intensify in the next few years, and many more exciting developments can be expected! Photoredox catalysis and electrosynthesis: drug discovery tools of the future!

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This article is here to help open your eyes to the chemistry around you. The chemical name and molecular of the hundreds of thousands of molecules around you. The molecular formula shows the proportions of ato molecular formula H2O which means there are two hydrogen atoms and one oxygen atom for every molecu one droplet of water! Finally to help you get the full experience with scientific language, the pronunciation is

Jo enjoys pancakes for breakfast, but not with accidental eggshell! Egg shells are made of calcium carbonate.

She prepares her pancake mixture on a marble kitchen surface which is also predominantly made of calcium carbonate.

The conversion of a yellow banana to a brown-spotted one is a prime example of a chemical reaction. Bananas contain polyphenol oxidase and other iron containing molecules, which react with oxygen in the air turning the fruit brown.

This rotting process is called oxidation and is the same chemical reaction which causes rust. The iron molecules oxidise, developing a red, flaky coating.

Flipping a pancake is hard enough, but even more disastrous if the pancake sticks to the frying pan. This is where TeflonÂŽ comes in, a polymer of tetrafluoroethylene (PTFE), which is used as the non-stick coating for cookware and containers.

She also adds baking powder to the mixture to help the cake rise. The active molecule in baking powder is sodium bicarbonate which reacts with other ingredients to release carbon dioxide (gas). As the baked goods become hot in the oven the gas expands and makes bubbles, causing the mixture to rise.

After breakfast, Jo carries out her chores, but why is it Washing machines live longer with Calgon ? Well, CalgonÂŽ contains sodium hexametaphosphate (amongst other ingredients) which softens hard water, preventing limescale from forming.

Unfortunately, the apartment Jo lives in has been infiltrated by pesky moths! With the cake in the oven, she orders some moth balls, hoping they will work. Moth balls contain 1,4-dichlorobenzene and undergo sublimation (go from a solid to a gas). The fumes released are toxic to moths and larvae, killing them or deterring their presence in that area.

Now that the washing machine is protected, Jo goes ahead with her wash cycle, and whilst waiting for the cycle to finish, she bakes a cake for her friends birthday party tonight. Banana cake is on the menu and luckily the bananas have started rotting (brown spots) which is key for a stronger banana flavour.

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Before her friends arrive tonight, Jo bleaches the toilet so i ll be squeaky clean for her guests. Bleach contains sodium hypochlorite. This active ingredient oxidises molecules within the cells of the germs, killing them, including viruses, bacteria, mould or fungi.


All cartoons were made by the app Bitmoji.

formula for a range of molecules found in household items are given, however this is just a small sample oms that make up a molecule using chemical element symbols and numbers. For example, water has the ule of water. Furthermore, to put molecule size into perspective, there are 1.67 x 1021 water molecules in given for the tricky or long chemical names.

I s a very sunny day, hard to believe Jo lives in the UK. The clothes wash has finished, so she hangs the washing outside to dry, before taking the cake out of the oven. Living near the coast, Jo takes full advantage of the weather and drives to the beach. First things first, she places her towel on the sand and relaxes. Sand consists of small grains of mineral and rock fragments. The dominant component of sand is the mineral quartz, which is composed of silicon dioxide.

After sunbathing, Jo goes for a refreshing swim in the sea and of course, accidentally swallows sea water. Sea salt is sodium chloride, which is also the salt used to flavour food.

As a classic seaside treat, Jo enjoys fish and chips for lunch with a sprinkling of salt and vinegar. Vinegar is mainly water with roughly 4% acetic acid.

Back home, i s time for Jo to freshen up and wash the sea salt out of her hair. Shampoo contains many molecules for colour, fragrance, thickening and conditioning. The molecule responsible for cleaning hair is a surfactant and sodium lauryl sulfate is the most commonly used. One end of the molecule dissolves in oil and grease (whilst lathering) and the other dissolves in water, carrying the dir away from your hair when rinsing.

Jo gets ready for the birthday party, starting with deodorant. The active ingredient for antiperspirant is aluminium chlorohydrate which, along with alcohol ingredients, kills bacteria for odour reduction. Jo uses a deodorant with a shower fresh fragrance, to keep her smelling great.

Her friends arrive, quickly followed by the opening of bottles and filling of glasses. Ethanol is the type of alcohol found in beverages and in this case is accompanied by mini umbrellas and garnish to enhance the party feel.

After a couple hours chatting, laughing and drinking, Jo lights the candles on the birthday cake. The flame is produced because of a chemical reaction: combustion. Energy is produced and transferred to the surroundings as light and heat flames. Fuel + oxygen → water + carbon dioxide + energy The party ends and Jo heads to bed to rest, ready to discover more molecules tomorrow.

Surfactants are also found in dishwashing and laundry detergent, plus bath gel.

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How are companies adjusting to provide a more sustainable future? Most of you will be aware of sustainable energy sources such as wind and solar power. Are there wind farms in your community? Maybe on the hills, or in the sea? Or perhaps solar panels on your roof or your neighbor ?

Harnessing this sustainable energy source powers homes, offices, and other buildings.

How can we ensure a sustainable future? What are we doing ourselves? What are businesses doing?

1

But before all that, what is sustainability?

The ability to meet our current needs without compromising the ability of future generations to meet their own needs. Whilst most people associate sustainability with environmental conservation alone, there are actually two more components: social responsibility and economic development. Sustainable economic development satisfies the needs of humans in a manner that sustains resources and the environment, for instance preserving global resources and switching to renewable resources where possible. Social sustainability encompasses the identification and management of business impacts, both positive and negative on people. The three pillars generally interlink; historically when communities develop (economic growth), the environment suffers as resource consumption increases. From a social perspective, both employers and consumers are directly affected by economic development, but also human health can suffer through indirect effects such as pollution.

20 People (Social)

Planet

Profit

(Environmental)

(Economic)

2

3

4

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A lot of commercial companies use natural nonrenewable resources but have embraced the concept of sustainability over the past decade and are now embarking on a more sustainable journey. Companies worldwide have committed to reducing their plastic usage, for example, supermarkets no longer offer single use plastic bags and instead sell bags for life in a range of designs.

Unfortunately, cars are too convenient to persuade everyone to use public transport and abandon their vehicles. Nevertheless, more and more car manufacturers are producing electric cars with higher energy efficiency and reduced pollution compared to petrol/diesel cars. Just a few brands include BMW, Toyota and Tesla, which offer fully electric or hybrid cars lowering the companie and their b er carbon footprint. For those of you who are fitness fanatics, Nike has focused on reducing waste and minimizing its carbon footprint. Adidas has also taken steps toward a more sustainable future by creating a greener supply chain, targeting specific issues like dyeing and eliminating plastic bags. Walmart, IKEA and H&M have collaborated with their supply chains to reduce waste, increase resource productivity and optimize material usage. Siemens is one of the orld most sustainable companies and constitutes businesses ranging from power plants to medical imaging machines. The company has a low carbon footprint and employee turnover, along with a growing portion of Siemen business being devoted to creating environmentally friendly infrastructure including green heating and air conditioning systems. Beyond the profit-making goal of every company, developing methods that minimize the damage caused to the environment, has become important, along with running the business in a manner that considers social and economic effects.


Six Key Factors for Achieving Sustainable Manufacturing 1.

Optimize the current use of fossil fuels.

2.

Eliminate waste.

3.

Reduce, or eliminate, pollution.

4.

Recycle.

5.

Recover energy, don't turn it into heat!

6.

Save time

Sustainable manufacturing can be applied to chemical reactions used to make products ranging from medicines to plastics to detergents. Usually you start with a smaller, less complex molecule and build it up step by step until you have your final product - just like completing a jigsaw puzzle.

Each step is a chemical reaction which requires, energy, materials, and time for a change to occur. But this i n the end. Often the product needs to be separated from a mixture and purified to remove any unwanted molecules, producing a lot of material waste. Sustainable reaction conditions include energy supplied from renewable resources and all materials being incorporated into the product to avoid waste and time spent separating molecules. Unfortunately, this is not usually the case, because some product losses are unavoidable. There is a field of chemistry which is inherently more sustainable than the common (step by step) method; late stage functionalisation (LSF). This technique follows the step by step sequence to a point, then uses that intermediate molecule to generate a whole range of molecules. This approach is key for drug discovery and development.

Unless over-consumption of resources and production of harmful fumes/ gases is minimized, modern civilization will collapse; we will run out of fossil fuels, thousands of animal species will become extinct, the atmosphere will be damaged beyond repair. There is a finite supply of non-renewable resources, meaning we will eventually run out of fossil fuels gas, coal, and oil. It is essential we find ways to use renewable resources. Hydro- (water), wind, wood, solar (sun) and wave power will not run out, providing a more sustainable alternative for our energy demand. For a healthy community we need clean air, natural resources and a nontoxic environment; environmental quality and public health are intricately related. Therefore, it is important that any negative effects of economic development are minimized and behaviors that positively impact the environment are emphasized.

LSF can quickly and easily produce a range of structurally similar molecules in the final steps of synthesis. Overall the number of steps to reach the molecules is reduced, requiring less time, energy and materials along with creating less waste! Unfortunately, there are a lot of challenges associated with LSF (which you can read about in the C-H functionalisation article on page 32), but as techniques and approaches continue to develop, new methods to successfully perform LSF are being generated.

Striving for sustainability in our way of living lies in understanding and implementing small changes at home, at work and in our 21 community.


1 Here are some tips: turn off appliances/lights, use a programmed thermostat or replace incandescent light bulbs with energy efficient LEDs.

2 Products, such as fruits and vegetables not in season, consume huge amounts of fossil fuel energy to get from global locations to your supermarket.

3 Don orr o don need acres of land j s a fe sq are fee can pro ide enough space to grow edible herbs, fruits, and vegetables.

4 Recycle as much as possible! For items such as CFLs (compact fluorescent lamps), batteries, mobile phones, and electronics, an appropriate recycler will need to be sought out.

5 Switch to a water-saving shower head, dual-flush toilet, drought-tolerant plant species which avoid excess watering, sprinkler systems to prevent watering the pavement/ drive.

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Items with the Fairtrade certification confirms they were grown using sustainable methods of agriculture and that local people are receiving fair prices for the goods they produce.

7 Using fossil fuels to support one person in each car is no longer sustainable. Car pooling or public transport would be more sustainable. Walking or riding a bike are the best alternatives, if travelling close to home.

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Items that you no longer need can get an extended life which will reduce products that end up in landfills and give to those in need, through charity organisations.


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What is Green

The goal of green chemistry is to minimise the gener design of chemical processes or products. The tw chemistry are

1

Waste Prevention Rather than generating waste and having to clean it up afterwards, green chemistry aims to plan processes that generate less waste or no waste altogether.

2

= 3

Atom Economy Every atom that goes into a chemical reaction comes out at the end, either incorporated into the product or as waste – no atoms are lost or gained. Green chemistry aims to reduce the number of atoms wasted by ensuring that the atoms from all reagents are incorporated into the product.

Less Hazardous Chemical Synthesis The hazards of all substances involved in a chosen process should be considered, and processes should be deigned to be as safe as possible, with minimal toxicity to human health and the environment.

4

!

Designing Safer Chemicals

Properties of chemicals and intermediates involved in processes, such as toxicity, physical properties (such as solubility) and environmental fate, should be considered and used to improve process safety. Chemicals should be designed to be safe without compromising their function.

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Safer Solvents and Auxiliaries

Many reactions between chemicals occur when the chemicals are dissolved in a solvent. Because the solvent makes up the bulk of waste from a reaction, it is important to consider the impact of solvent choice, and to use the safest solvent available for each step of a synthetic process. Other things used up in chemical process but not involved in the chemical reaction, such as drying agents, must still be considered when evaluating a route.

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Design for Energy Efficiency

As well as avoiding chemical waste, green chemistry aims to minimise energy waste, in turn minimising the environmental and economic impact of the chemistry. Ideally the least energy-intensive route should be used. As well as heating reactions, energy is used in cooling, separating, pumping, regulating pressure and other energy expenses.

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n Chemistry?

ration and use of hazardous substances through the welve principles that underpin the area of green e as follows:

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Use of Renewable Feedstocks Chemicals originating from petrochemical sources are not renewable, and their continued use is not sustainable. Renewable feedstocks are sources of chemicals which can be replenished, such as plant-based sources. Green chemistry aims to use renewable resources to ensure processes are sustainable.

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Reduce Derivatives

In its journey from a starting material to a final product, a chemical may be transformed into an array of intermediates before the end of the process. Minimising the number of intermediates that one chemical has to go through to become the final product reduces the number of reaction steps. This in turn reduces waste, resource consumption and energy use.

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Catalysis

Catalysts reduce energy consumption by speeding up reactions and allowing them to proceed with reduced energy input. Also, catalysts reduce waste because they are not used up in chemical reactions, meaning that they can be used repeatedly. See page 26 to learn more about catalysts!

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Design for Degradation

As well as waste generated in the production of a chemical product, it is important to consider the life cycle of the product itself. Products should not be toxic, bioaccumulative, or persistent in the environment.

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Real-time Pollution Prevention

Real-time monitoring of processes and their waste generation can be used to prevent the formation and release of hazardous pollutants to the environment.

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Safer Chemistry for Accident Prevention

Processes should be chosen to minimise risk to those carrying them out, and to the surrounding environment and community. Any unavoidable risks should be assessed before the process is underway, and a plan should be made for use in the unlikely event of an incident.

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catalysis in late-stage functionalisation ...the key to cleaner, more efficient chemical synthesis The word catalyst is a regular part of our everyday vocabulary, used to mean anything that can speed up an event or occurrence. But what does it mean in a scientific sense? In the realm of chemistry, a catalyst expedites a reaction by providing an alternative avenue by which it can proceed. This alternative reaction pathway requires a lesser input of energy, allowing a reaction to proceed faster at a given temperature or lowering the temperature at which a reaction can proceed. Catalysis has become one of the lynchpins of modern synthetic organic chemistry. The advent of sophisticated new catalysts has arguably been the main enabling factor in the development of cutting-edge latestage functionalisation chemistry in recent years. The use of catalysts has several key advantages: Catalyzed reactions can often be run at lower temperatures than their uncatalyzed counterparts, saving energy and lessening the possibility of molecular degradation. Catalytic processes are cyclic in nature, with the catalyst being regenerated after each turnover. This means that catalytic reactions are usually more efficient and less wasteful than their uncatalyzed counterparts, as a small amount of catalyst can do a lot of chemistry! Catalysts can enable certain chemical reactions that are essentially impossible without them, which is especially important to specific strategies in organic synthesis such as late stage functionalisation which will be explored in more depth later.

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The technical reason why catalysts are essential for enabling certain chemistries lies in the science of thermodynamics. In a nutshell, thermodynamics describes the relationship between various forms of energy, such as heat and light, and their interplay with physical matter. A thermodynamic concept called the activation barrier is key to understanding why catalysis is so important in chemistry. The activation barrier associated with a chemical reaction describes the amount of energy that needs to be supplied in order for the reaction to proceed. The higher the barrier, the more energy (often heat) that needs to be supplied to the reaction mixture. Although many reactions in organic chemistry happen easily at moderate temperatures, many others with high activation barriers do not. Conducting chemistry at very high temperatures to promote thermodynamically unfavourable reactions is not only energy-inefficient, it also risks significant molecular degradation and promotion of unwanted side-reactions. Development of a suitable catalyst is necessary to circumvent these issues. Contemporary C-H activation chemistry, which is described in more detail in another article, highlights the power of catalysis in modern organic synthesis. As most carbonhydrogen bonds in organic molecules are strong and inert, breaking them to add in new chemical groups is simply unfeasible without the use of a catalyst in most cases. As many innovative catalytic systems have been designed to promote this type of chemistry in recent years, this class of reactions has become a central tool in late-stage functionalisation.


Although all catalysts operate under the same broad principles, they can take many forms. Transition metal catalysis is a major area of historic and ongoing research in chemistry, as complexes of many metals can promote a wide array of useful reactions. The so-called pla in m g o p metals are overrepresented in this area, as they are despite their scarcity and expense are the basis of some of the most important catalysts in organic chemistry. Photocatalysts, which promote reactions using light, are another important class. Organic dyes and complexes of the rare metal iridium, both of which absorb light efficiently, are examples of this type of catalyst. Natural catalysts also exist: enzymes are biological catalysts that can promote a variety of chemical reactions. Enzymes are responsible for some of the highly complex natural product molecules produced in animals and plants, many of which have been isolated and tested for medicinal properties. Enzymes have also been harnessed for industrial processes, as they can often be grown under artificial conditions to promote specific chemical reactions on a large scale. Further advancements in catalysis are likely to accelerate innovations in the field of synthetic organic chemistry. Late-stage functionalisation and C-H activation are still relatively nascent areas of research and the development of innovative catalytic systems will likely further enrich these areas of research in the future by enabling exciting new chemistries. The chemical industry as a whole is heavily invested in catalysis research, as catalysis is seen as one of the key tools for developing greener, more sustainable and more efficient chemical processes.

...many useful catalyst complexes (MIDDLE and BOTTOM) contain precious platinum-group metals (TOP).

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Illustrating C-H Functionalisation with IKEA furniture... 1. Imagine you are moving into a new city and an unfurnished apartment awaits you. The first thing you look for is furniture and so you make a trip to IKEA. As you wind your way through the furniture exhibits, you find the piece of furniture you want to fit in your new apartment.

2. You end up in a room full of boxes of furniture with Scandinavian names. You pick the table you saw in the exhibits, pay for it and pack it into your car. Once home, you open the table box to find some legs, instructions, screws, table top, and maybe an Allen key.

3. Holding a leg up to the table, you put a screw into the pre-drilled hole and start spinning the key until it is all the way in. Repeating this a few more times, you have a table. The table is nice, but you can’t help but wonder if it is a bit too tall, or too small or if you want another surface underneath the top. But you are stuck now, so you shrug your shoulders and move on.

= Functional Group

4. Interestingly, the way you put together that IKEA table is similar to how chemists put together important molecules such as medicines. In a molecule, there are various parts which are called functional groups (FGs). These groups act as the ‘drilled holes’ and different parts can be attached to them. But if you try to stick anything anywhere else than these functional groups, then you will have as much luck as you would sticking a leg to the table, using an Allen key and screw, without the pre-drilled holes.

5. Wouldn’t it be cool if we had the freedom to attach anything we wanted, anywhere we wanted on the table or molecule? Maybe this will result in the perfect table, or even a drug molecule that could treat a specific disease.

Disease

4 Drug Candidates – only one successful

6. The difference between drugs treating different diseases can sometimes involve the addition or subtraction of just a few atoms in the correct positions.

7. With atom location playing a major role in the properties of the molecules as drugs, finding a way to selectively install these atoms, without the need for already installed functional groups/pre-drilled holes, would be valuable. Here we introduce carbon to hydrogen (C-H) bond functionalisation. A type of reaction that can be used by scientists make new molecules which have the potential to become new medicines. C-H Functionalisation

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C-H Functionalisation EXPLAINED How do scientists make compounds conventionally? Carbon to hydrogen (C-H) bonds are the most abundant type of bond in organic molecules. In comparison to other chemical bonds found in molecules, C-H bonds are generally unreactive. As a result, scientists have found that directly reacting these bonds can be very challenging. Conventionally, to make complex molecules, scientists focus on the reactions of functional groups, which are generally more reactive than C-H bonds, making it easier to change the molecule using these groups. The process of making (or synthesising) complex molecules usually requires multiple steps to build the structure piece by piece, like a jigsaw puzzle. Functional groups are found in certain areas on a molecule, hence specific atoms are added in specific positions using the functional groups.

What is C-H functionalisation and what are the advantages of this type of reaction in comparison to conventional ways to make molecules? Unlike conventional methods used by organic chemists, C-H functionalisation does not rely on the reaction of functional groups. C-H functionalisation can be explained using the diagram below. Starting with the organic compound at the far left, this molecule contains multiple C-H bonds but one is shown just for simplicity. Selective C-H functionalisation reactions directly target a particular C-H bond in a molecule and the reaction results in the formation of a new chemical bond with a second organic chemical group, atom or group of atoms. C-H functionalisation can be advantageous compared to conventional methods. Firstly, reactions which target a specific C-H bond usually require less steps to form the desired product (with the new chemical bond). This is because usually a functional group must be pre-installed, creating a reactive point, allowing the desired organic group to be attached onto the molecule. Reducing the number of steps saves time and energy, whilst reducing the cost of chemicals required for each step. Furthermore, this reduces the amount of waste material produced in each reaction step, showing environmental and sustainable advantages of C-H functionalisation. New Chemical Bond

Chemical Bond

C

Organic compound

Catalyst, Light Energy

H

Organic group

C

How can C-H functionalisation be used in the discovery of new medicines and treatments? Medicinal chemists working in research and development teams in pharmaceutical companies have the overarching aim of synthesising molecules that have the desired chemical and biological properties to treat a target disease or condition. Medicinal chemists usually start from scratch and carry out multiple step synthesis to build up a molecule piece by piece. Once made, these molecules get submitted for biological testing to see if they are biologically active and have the right properties to become a medicine. If found to be biologically active, molecules with similar structures are made to see if they have improved properties. To make a molecule with one small change, such as a different chemical bond or atom, scientists usually have to start from the beginning again, building up this slightly different molecule step by step. In this context, C-H functionalisation can be used to facilitate this process, removing the need to start from scratch. By using C-H functionalisation reactions on the original, biologically active Molecule A (diagram below), we can access a range of other molecules with different chemical bonds. These different bonds can promote different chemical properties (such as solubility or activity), resulting in library of molecules that have the potential to become medicines, treatments and therapeutics. 1. Multiple steps are usually required to make target Molecule A which was found to have promising biological activity.

Molecule A

= C

C

H

2. C-H functionalisation of Molecule A to various different compounds with potential biological activity.

C C

New attached organic group

Compound Library

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Glucose Sunlight Carbon dioxide Photosynthesis (sugar) Oxygen Water

Photochemistry is a sub-discipline of chemistry which studies chemical reactions that proceed when atoms or molecules absorb light. The role of light in effecting chemical change has been recognized for many years, especially in nature, where organisms have evolved to respond to light in numerous ways. Plants use a process called photosynthesis where they absorb solar energy to convert carbon dioxide and water into glucose (sugar) and oxygen. The retina (inner lining of the eyeball) also responds to light using specialized cells called photoreceptors. Once light is absorbed, rapid chemical reactions are triggered within the eye, resulting in vision and changes in pupil size to regulate the amount of light entering the eye. With bright light the pupil constricts, and under dim conditions, the pupil dilates. One of the first reported photochemical synthetic reactions was in 1866, however, significant contributions have only been made in the last 70 years. This is because understanding photochemistry and how to design light-driven reactions is challenging, and these areas are continuing to be developed to this day. Photochemistry has been applied to drug syntheses, including a new approach to ibuprofen, the production of an anti-malaria drug (artemisinin) and the synthesis of antiviral agents. Domestic products such as cleaning solvents and insecticides can also be produced from photochemical reactions. Not only can light be used to make useful products, but it can be used to break molecules apart too. Photodegradable plastics can absorb light, causing polymer bonds to break and hence decompose the plastic, at a faster rate compared to normal plastics.

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Breakthroughs in light technology, including the invention of the laser just over 50 years ago, continue to revolutionize the medical industry. Medical imaging (creating visual representations of the body interior), surgical procedures, and even diagnoses rely upon the use of light.

Photodynamic therapy (PDT) uses photochemistry to treat some skin and eye conditions, along with certain types of cancer. Photodynamic therapy involves a light-sensitive medicine being administered and absorbed by the cancer cells. A beam of light illuminates the specific area and generates a special kind of oxygen molecule which reacts with the drug to kill cells. The light used in PDT comes from certain kinds of lasers or LEDs. These allow the area of treatment to be targeted very precisely and usually for only a short time (a much less invasive treatment than surgery). 1. Administration 2. Accumulation 3. Light delivery 4. Assessment

PDT

When used properly, there are no longterm side effects and little or no scarring is observed. Unfortunately, PDT can only treat areas where the light can reach (just under the skin) and alternative treatments are required for cancers that have spread to many places. Energy, Space and Time Control


In a chemical reaction, a molecule is manipulated by breaking part of the molecule, adding another molecule, or rearranging the molecular structure to give a desired product. Most of these transformations require energy, often provided in the form of heat or light, both of which are valuable energy sources.

reactions aren generally performed outside, laser and LED (light-emitting diode) light sources are more appropriate. These light sources trigger a chemical reaction by emitting either UV or visible light at molecules.

A photochemical reaction is a chemical reaction triggered by the absorption of light.

Molecule

Only specific molecules, or certain parts of a molecule, can absorb light and utilise the energy. Furthermore, a unique energy of light is often

required; if the energy is too high or low, the desired reaction will not occur. Light consists of a broad spectrum of colours (red, orange, yellow, green, blue, indigo and violet) with corresponding energies. For example, red light has the lowest energy and violet has the highest energy. Interestingly, white light is the combination of all colours and energies. Beyond visible light there is also ultraviolet (UV) light which can be used in photochemistry; however, the higher energy can cause some molecules to decompose. The most efficient way to perform a photochemical reaction uses monochromatic light. This type of light has one colour, hence one energy. Monochromatic light avoids wasting energy that is not absorbed by the molecule and favours the desired transformation over reactions that could result from other energies. When another part of the molecule absorbs a different energy of light this can result in an unwanted change known as a side reaction. Using a light source emitting only one colour (for the desired change) can avoid these side reactions. Ideally (from a sustainability point of view) the light used would come from the sun, but considering we live in the UK and chemical

LED or Laser Illumination

Lasers and LEDs are energy efficient, monochromatic and can be bought in a range of colours. A common set up includes flexible LED strips wrapped around a dish, in which a glass container, containing everything you need for a reaction, can be held in the middle to absorb light from all directions. For photochemistry, the transparency of glass is a crucial property enabling the light to reach the target molecule. Sometimes UV light has trouble passing through the glass to reach the molecules because glass absorbs nearly all UV light (the reason you can get sunburn through glass!) The optical path length is the length of the path which light irradiation follows, passing through the glass. A long path length may result in the light not reaching the molecules; conversely, a shorter path length may result in too much intensity (potentially degrading the molecules). Therefore, the distance between the light source and the reactor is important. Inside the reactor, there is often a photocatalyst - a molecule that can also absorb light but pass the energy onto the desired molecule; facilitating the reaction. The catalyst remains unchanged, it is simply there to help speed up the reaction, whilst minimizing waste and energy demands.

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Driving Reactions with Electricity Driving chemical reactions with electricity is something most of us do on a daily basis – but can this technology rival heat as an energy source, in the lab and at industrial scale? Often without even realising that e re doing it, we start and stop chemical reactions in our own homes without the need for specialised equipment and a chemistry lab. Whether these are reactions driven with heat (frying an egg), light (developing a polaroid photo), or electricity (charging a phone battery), they all involve a reaction to convert one chemical into another. Electrochemistry the relationship between electricity and chemical change is probably known best for its use in battery technology, which developed from the invention of the Volta pile in 1800 by Alessandro Volta. Ancient civilisations knew of electricity the Greeks described static electricity generated by rubbing amber with animal fur, and the Egyptians used the shock of the electric catfish to treat arthritis. However, it asn t until 1800 that the first source of a steady flow of electricity, the Volta pile, was invented. Since then, battery technology has become integral to the way we live our lives. Life without battery-powered devices like mobile phones, computers and laptops is almost inconceivable. Inside a battery, chemical reactions take place which remove electrons charged particles that carry electrical current - from the positive terminal of the battery, and deposit them at the negative terminal. When a circuit connects the two terminals, electrons start flowing around the circuit. We take advantage of this flowing electrical current by using it to power lights, computers, and all sorts of other appliances. .

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Discharging a battery is an example of a chemical reaction producing an electrical current, but the reverse process using electricity to drive chemical reactions is also possible. A simple example of this is the charging of rechargeable batteries. Supplying an electrical current to the battery in the opposite direction to its discharging current will reverse the chemical reaction inside the battery, and it will be ready to use again. The use of batteries in toda s society warrants a massive drive for research and investment - a 2018 Engineering and Physical Sciences Research Council (EPSRC) report projected a ÂŁ2.7 billion per year market for UK battery manufacturing. In July 2020, Tesla Inc., specialising in electric vehicles and battery storage technology, reached a market capitalisation of over ÂŁ165 billion, taking its place as the orld s most valuable carmaker. Many scientists researching electrochemistry are working to improve the properties of batteries such as their energy storage capacity, charging speed or the lifetime of batteries before they begin to degrade.


With growing concern for the planet s climate and limited resources, the use of renewable energy sources as a replacement for fossil fuels is always increasing. Energy sources such as wind, solar, and tidal power in the National Grid come with an increased demand for energy storage. The inconsistent nature of these power sources requires energy to be stored and released at controlled rates to balance supply and demand, adding to the drive for improvement to battery technology. Another common example of an electrically driven chemical reaction is the electroplating of metals. Developed in 1805, using the Volta pile invented five years earlier, this process is used to deposit a layer of solid metal onto the surface of a desired object. The object is submerged in a dissolved form of the metal, and an electrical current is passed through the object and solution. Electricity drives the chemical reaction that converts the dissolved form of the metal into solid metal on the object s surface. This process is used to plate jewellery, car parts, circuit components, and was even used to goldelectroplate the dome of the Cathedral of Christ the Saviour in Moscow.

Another field of research in electrochemistry is synthetic electrochemistry. Synthetic electrochemists use an electrical current to drive a chemical reaction in the synthesis of a target molecule. Because .

the bonds between atoms that hold molecules together are made up of electrons (the same particles which flow around a circuit in an electrical current), using electricity for synthesis is a way to directly interact with the bonds in molecules. By breaking and forming the right bonds, molecules can be transformed into a target molecule. The first example of using electricity to synthesise an organic molecule was reported by Michael Faraday in the early 19th century, when he discovered that applying an electrical current to acetic acid converted it into ethane. Since then, electrosynthesis has been used in the synthesis of much more complex molecules. The goal of many researchers focusing on electrosynthesis is to replace conventional methods in chemistry, which often use heat to drive reactions, with milder electrochemical conditions. Electrochemistry has been adopted for many chemical processes on the industrial scale. Pure aluminium is obtained from the electrolysis of aluminium oxide, and the electrolysis of sodium chloride (salt) is used to obtain chlorine and sodium hydroxide, both of which are commodity chemicals required by industry. There are many benefits to using electricity to drive reactions instead heat. Electrochemical reactions can be started and stopped instantly, unlike heat-driven reactions that often need to cool down after the reaction is done. The ability to complete chemical reactions at lower temperatures makes the chemistry safer and less energy-intensive to carry out, and is sometimes a way to make a molecule that could decompose at higher temperatures. Electrochemical methods can be used to reduce the consumption of resources and generation of waste by directly supplying electrons from a circuit, rather than relying on chemicals to deliver them.

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Industr s use of electrochemical methods is not surprising, as the method developed to make a chemical is focused on efficiency and cost, rather than convenience to the researcher. With an ever-growing understanding of electrochemical methods, the prevalence of this technique at the industrial scale will certainly increase in the future. On a lab scale, the chemical method chosen to complete a reaction is often determined by convenience, and this has resulted in a reduced uptake of electrochemical techniques. Most synthetic chemists are unfamiliar with the use of electricity for synthesis, and the use of electrochemical methods requires expensive and regularly maintained equipment that many researchers don t have access to. It is more convenient to .

use a less efficient or less environmentally friendly method based on the equipment and chemicals the researcher has available to them. Fortunately, the scientific equipment required to conduct electrosynthesis is becoming more affordable and easier to use, and will no doubt see increased uptake soon. Although electricity will never be able to replace the convenience of thermally driven reactions, the ability of electrochemical methods to complete some reactions more efficiently, or sometimes to complete reactions that are impossible using conventional thermal methods, should make electrochemical methods a valuable counterpart to thermal methods in chemical synthesis.

+

+ Acetate Ions (H3CCO2-)

Ethane (H3CCH3)

Hydrogen (H2) Protons (H+)

Carbon Dioxide (CO2)

Farada s pioneering electrosynthesis work - forming ethane, carbon dioxide and hydrogen from acetic acid. Acetic acid in solution forms acetate ions and protons. As the power supply moves electrons around the circuit, electrons are removed from the acetate ions, to form methyl radicals and CO2. The methyl radicals bond together to form ethane. Simultaneously, electrons are moved onto the protons to form hydrogen gas.

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Chemistry Crossword

•Down •1. Harnessing the energy of light to promote chemical reactions. •2. A liquid that is used to dissolve other chemicals. •3. Avoiding the depletion of natural resources. •4. A class of bioluminscent molecules used by animals. •5. A flat cyclic molecule consisting of six carbon and six hydrogen atoms. •6. Raw material for a chemical process. • Across •7. A substance that is used to expedite a chemical reaction. •8. The use of an electrical current to drive a synthetic reaction. •9. A biological catalyst. •10. A branch of fine chemicals used as pesticides and fertilisers. •11. A compound consisting of only carbon and hydrogen atoms.

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Some scientists work in a laboratory and have to make sure that they are safe and protected. Here are some things that you can do when you are in a science class, to keep you safe! 1. Tie our long hair back and wear shoes that cover our feet. This makes sure that we don't spill anything toxic on our feet or stand on broken glass! 2. Wear safety goggles, gloves and a laboratory coat. This is to make sure we protect our eyes and our clothes from any chemicals. 3. No eating or drinking in the laboratory. This can get mixed up with the science we are doing and this can be very dangerous if we eat the chemicals in the laboratory. Ask your parents, your brother or sister, or a family member to help you scan this QR code! By holding a phone camera to this code, it takes you straight to a video explaining general lab safety in the laboratory! Science is fun but always make sure you are safe and protected!

1. Glasses 2. Gloves 3. Bottom pocket on lab coat 4. Tail 5. Different colour solution in test tube (hard to see) 6. Smoke from container in left hand 7. Extra table legs

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Climate Change Scientists have discovered that our planet is getting hotter – and this could be a big problem one day. Even though it s nice to be warm, the planet getting hotter is bad news for some animal habitats and causes wilder weather and rising sea levels.

°C

The sun naturally warms up the planet, but pollutant gases like carbon dioxide, methane and nitrous oxide absorb the heat and stop Earth naturally cooling, like a blanket around the planet. We can help prevent climate change by walking or riding a bus instead of using car, remembering to switch off lights and trying not to use electricity and water when we don t need to.

Chemistry Wordsearch!

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Can you find all 10 hidden words in the wordsearch?

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ATOM BEAKER CARBON CHEMISTRY EXPERIMENT LABORATORY MOLECULE REACTION 37 SAFETY SUSTAINABILITY


Analogue a compound with a molecular structure closely similar to that of another.

Function

a group of atoms respon reactions of a pa

Biocatalyst

Hydro

living biological systems, or their parts, that are used to speed up (catalyse) chemical reactions – an example includes enzymes.

a class of chemicals m carbon only. Of

Catalyst a substance that speeds up a chemical reaction without being changed itself.

Electrochemistry

Inorganic

the use of electricity to initiate a chemical reaction.

molecules that are not prima elements such as pallad

Enzyme

Molecula

a class of biological catalysts that are produced by all living things which enables a chemical change or speeds one up, without being changed itself.

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a chemical formula that i atoms in a molecule. Usual Y are atom types and n


nal Group

nsible for the characteristic articular compound.

ocarbon

made up of hydrogen and ften used as fuels.

Organic Molecule organic - primarily focuses around the element carbon; molecules - two (or more) atoms joined together by chemical bonds.

Photochemistry the use of light to initiate a chemical reaction

Solvent a liquid that can dissolve other chemicals and is often used as the medium of a reaction.

c Molecule

Synthetic

arily based on carbon, containing dium, rhodium and iridium.

artificial; made by combining molecules rather than being produced naturally by plants or animals.

ar Formula

Thermochemistry

indicates the type and quantity of lly in the form as XnYm, where X and n and m represent the quantity.

a branch of chemistry involving the study of the quantities of heat evolved or absorbed during chemical reactions.

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