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What is the definition of green chemistry?
Green chemistry (also known as sustainable chemistry) is a discipline of chemistry concerned with the design and optimization of processes and products to reduce or eliminate the production and use of harmful compounds. Environmental chemistry is not the same as green chemistry. The former focuses on the environmental impact of chemistry and the creation of environmentally friendly sustainable methods (such as a reduction in the consumption of non-renewable resources and strategies to control environmental pollution). The latter is concerned with the environmental effects of some poisonous or hazardous compounds.
The 12 key principles of Green Chemistry
The following are the twelve principles proposed by American chemists Paul Anastas and John Warner in 1998 to build the groundwork for green chemistry.
1.Waste prevention: avoiding the development of garbage products is always preferable to cleaning up waste that has already been formed.
2.Atom economy: green chemistry-based synthetic processes and technologies must always strive to maximize the consumption and incorporation of all raw materials into the final product. To reduce waste caused by any process, this must be closely adhered to.
3.Avoiding the production of hazardous chemicals: reactions and processes that entail the synthesis of certain toxic substances that are harmful to human health must be improved to avoid their production.
4.Designing safe chemicals: When creating chemical products that perform a specific function, special attention must be given to ensure that the chemical is as non-toxic to humans and the environment as feasible.
5.Design of safe auxiliaries and solvents: auxiliaries should be avoided in processes to the greatest extent practicable. Even in situations where they are absolutely necessary, they must be tuned to be as non-hazardous as feasible.
6.Energy efficiency: The amount of energy consumed by the process should be kept as low as possible.
7.Renewable feedstock and renewable raw materials must be chosen over non-renewable feedstock and raw materials.
8.Derivatives should be used only when absolutely essential, as they often necessitate the use of extra reagents and chemicals, resulting in waste formation.
9.The use of chemical catalysts and catalytic reagents must be supported in order to lower the energy requirements of the chemical reactions in the process.
10.Designing chemicals for degradation: When creating a chemical product to perform a specific purpose, special care must be given to ensure that the chemical is not an environmental pollutant. This can be accomplished by ensuring that the chemical degrades into non-toxic compounds.
11.Real-time analysis should be incorporated: procedures and analytical methodologies should be improved to the point where they can provide real-time data for monitoring. This allows the parties concerned to halt or regulate the process before harmful or dangerous compounds are produced.
12.Incorporation of safe chemistry for accident prevention: When designing chemical processes, it is critical to ensure that the compounds employed in the processes are safe to use. This can help to avert workplace disasters like explosions and fires. Furthermore, this can aid in the creation of a safer environment in which the process can take place.
Examples of Impact of Green Chemistry
Uses of Green Solvents
On an industrial scale, many chemical synthesis reactions necessitate significant volumes of chemical solvents. These solvents are also utilized in the industrial sector for degreasing and cleaning. However, many of the traditional solvents that have been employed for this purpose in the past have been proven to be hazardous to humans. Some of these solvents are chlorinated as well.
Many alternatives to these harmful solvents have been developed thanks to advances in green chemistry. Green solvents that are being developed as alternatives are known to be biodegradable and sourced from renewable sources. As a result, green chemistry holds a lot of promise for reducing the toxicity of particular industrial environments by discovering safer alternatives.
Specialized Synthetic Techniques Development
The creation of specialized synthetic methodologies can improve processes and make them more environmentally friendly by adhering to green chemistry principles. The development of the olefin metathesis process in organic chemistry is a good example of such an improved synthetic approach. Robert Grubbs, Richard Schrock, and Yves Chauvin invented this process, which won the Nobel Prize in Chemistry in 2005.
Other important advances brought forward by green chemistry advancements include:
1.As a green solvent, supercritical carbon dioxide is used (as an alternative to other toxic solvents).
2.Enantioselective synthesis processes with hydrogen incorporation (also known as asymmetric synthesis).
3.Using hydrogen peroxide (a chemical molecule with the formula H2O2) aqueous solutions to conduct relatively clean oxidation processes.
4.Other significant green chemistry applications include supercritical water oxidation (SCWO), dry medium reactions (also known as solid-state reactions and solventless reactions), and water reactions.
Hydrazine production
The Olin Raschig process, which used ammonia and sodium hypochlorite, was once the most prevalent technique for producing hydrazine (an inorganic chemical compound having the molecular formula N2H4). A more environmentally friendly alternative to this technique was identified with the invention of green chemistry.
Ammonia is reacted with hydrogen peroxide in the peroxide process to produce hydrazine. Only water is created as a byproduct in this alternative approach. It’s also worth noting that the peroxide technique doesn’t require any additional solvents for extraction.
Conclusion
We conclude that Green chemistry attempts to create and manufacture cost-competitive chemical products and processes that reduce pollution at its source, achieving the highest degree of the pollution-prevention hierarchy. The following chemicals are less harmful to human health and the environment: Organisms are less harmed.
