It is the backbone of industries ranging from pharmaceuticals and materials science to agriculture and energy. Through carefully controlled reactions, chemical synthesis allows for the creation of everything from life-saving drugs to cutting-edge materials that shape our daily lives.
So, what is chemical synthesis? Put simply, it is the production of chemical compounds by reaction from simpler materials. The goal of synthesis is to design the most efficient ‘pathways’ from reactants to products, through a series of controlled chemical reactions that require extremely precise measurements and specific reaction conditions, such as temperature, pressure or catalysts.
An example of the use of chemical synthesis is in the production of ammonia through the Haber Process. Although ammonia is present in trace amounts in the atmosphere and is produced by the anaerobic decay of plant and animal matter, there is not enough of it to satisfy demand. (It is needed for fertilisers, as it is rich in nitrogen, which is converted into nitrates that are used by plants to make proteins.) The Haber process converts atmospheric nitrogen (N2) into ammonia (NH3) through a reaction with hydrogen (H2). Finely divided iron metal is used as a catalyst and, as it is a reversible reaction, both the temperature and pressure of the reaction need to be very high, at about 450°C and 200 ATM.
Another use of chemical synthesis is in pharmaceuticals when creating new drugs. Chemical synthesis enables the discovery and optimisation of complex molecules with strong, selective biological activity, meaning that researchers can chemically modify existing drugs. This allows us to balance chemical properties and find the right strength and dosage for patients, thereby optimising drug effectiveness and minimising side effects. New reaction development is another essential facet of this branch of chemical synthesis: it opens previously inaccessible routes to new compounds by allowing chemists to design and build complex molecules that interact with specific biological targets. This capability is crucial to discovering treatments for diseases that lack effective therapies, including those that were previously considered untreatable. Chemical synthesis is currently being explored as a way to increase sustainability within pharmaceuticals. The main issue with this is that the typical chemical synthesis process is very energy-consuming and, depending on the reactants and desired product, generates significant waste. However, the focus is on making chemical synthesis more sustainable, by minimising waste through catalysts and looking into the principles of atom economy (the mass of desired products relative to the total mass of products).
Chemical synthesis has the potential to be greatly impactful in the field of material science. In the past, we were able to create alloys by combining metals at high temperatures, allowing the final product to have special properties; now, we can use chemical synthesis to create a version of this for other materials, including polymers or even nanomaterials. This means that these materials will have tailored properties for their specific applications. For example, polycarbonates and polyethereetherketone (PEEK) are used in aerospace automotives and medical industries due to their strength and heat resistance, while polylactic acid (PLA) is a biodegradable polymer, synthesised for usage in sustainable packaging and medical devices to reduce their environmental impact.
While chemical synthesis does have a way to go in terms of sustainability, it enhances processes in many industries, such as pharmaceuticals and manufacturing, by enabling the creation of complex molecules and materials. As the field continues to evolve and grow, the development of more efficient, environmentally friendly, and cost-effective synthetic methods will further propel scientific advances and contribute to a more sustainable and technologically advanced future.
Abigail (VII)