Green Chemistry is a new branch of chemistry that falls under cradle-to-cradle methodology, taking a proactive, preventive approach instead of the retroactive treatment approach now currently employed throughout the world. It is the design of chemical products and processes that reduce or eliminate the use or generation of hazardous substances from industrial products. The development of safer chemicals and processes eliminates or reduces pollution at its source by minimizing or eliminating the hazards of chemical feedstocks, reagents, solvents, and products. This is unlike cleaning up pollution (also called remediation), which involves treating waste streams (end-of-the-pipe treatment) or cleanup of environmental spills and other releases. It is a paradigm shift to design ecologically hazardous materials out of products.
In the new economy, some industries will need to undergo paradigm shifts while other industries may either disappear altogether or downsize dramatically. The chemical industry has had a significant role in shaping our modern world but must now undergo radical change if it is to adapt to the new world. In particular, industries will need to be based around low energy and lowfeedstock and processes which do no harm. Industries have relied too much on cheap and polluting fossil fuels need to reinvent themselves.
12 Principles of Green Chemistry
It’s better to prevent waste than to treat or clean up waste afterwards.
- Atom Economy
Design synthetic methods to maximize the incorporation of all materials used in the process into the final product.
- Less Hazardous Chemical Syntheses
Design synthetic methods to use and generate substances that minimize toxicity to human health and the environment.
- Designing Safer Chemicals
Design chemical products to affect their desired function while minimizing their toxicity.
- Safer Solvents and Auxiliaries
Minimize the use of auxiliary substances wherever possible make them innocuous when used.
- Design for Energy Efficiency
Minimize the energy requirements of chemical processes and conduct synthetic methods at ambient temperature and pressure if possible.
- Use of Renewable Feedstocks
Use renewable raw material or feedstock rather whenever practicable.
- Reduce Derivatives
Minimize or avoid unnecessary derivatization if possible, which requires additional reagents and generate waste.
Catalytic reagents are superior to stoichiometric reagents.
- Design for Degradation
Design chemical products so they break down into innocuous products that do not persist in the environment.
- Real-time Analysis for Pollution Prevention
Develop analytical methodologies needed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.
- Inherently Safer Chemistry for Accident Prevention Choose substances and the form of a substance used in a chemical process to minimize the potential for chemical accidents, including releases, explosions, and fires.
Some examples of Green Chemistry applications
- Extract valuable chemicals from biomass that could form the initial processing step of many future biorefineries.
- Wax products with numerous applications, can be extracted from crop and other by-products including wheat and barley straws, timber residues and grasses, using supercritical carbon dioxide – a green chemical technology that allows the production of products with no solvent residues
- Extracted residues can be used in applications including construction as well as in bioprocessing
- Low-temperature microwaves can also be used to pyrolyse biomass, allowing greater control over the heating process. The process results in significant energy savings and produces high quality oils, and oils and solids with useful chemical properties.
- Combining continuous extraction with microwave irradiation, it is possible separate an aqueous phase leaving the oils cleaner, less acidic and with lower quantities of other contaminants such as alkali metals. The oils have significant potential as feedstocks for making chemical products as well as for blending into transport fuels.
- Production of bio-chars with calorific values and physical properties that make them suitable for co-firing with coal in power-stations
(Source: Professor James Clark, Director of the University’s Green Chemistry Centre of Excellence, University of York)
- Berkeley Center for Green Chemistry is partnering with the Biomimicry Institute to consider biologically inspired design alternatives as a starting place for the replacement of formaldehyde based resins, adhesives and preservatives which are used in textiles and beauty products.
Figure 1: Prezi Green Chemistry and E-waste presentations
Green Chemistry References
- Warner Babcock Institute For Green Chemistry
- Beyond Benign Green Chemistry Education – dedicated to providing future and current scientists, educators and citizens with the tools to teach and learn about green chemistry in order to create a sustainable future.
- Green Chemistry Education Network
- Green Chemistry Institute of the American Chemical Society
Bioplants and Biorefineries