Green Chemistry

It is a developing science and a branch of chemistry dealing with eco-friendly or environmentally benign chemical feedstocks,processes and products.This term was first coined in the last decade by Paul T Anastas. Researches are going in this field all round the globe. But till now only <1% reactions have been covered under this rapidly emerging field.

”Green chemistry is a way of bringing back the perspective that chemicals aren’t all bad. Of reminding citizens that chemistry is the very basis of the social and economic life of virtually all industrialized nations. Everything around us is a chemical. There are hazardous and toxic chemicals, but also a lot of chemical wonders. So we’re trying, through green chemistry, to put chemistry in a very positive light: to show that it can actually be used to solve even our most pressing environmental issues, through the development of alternative technologies. Chemists have the knowledge to design chemical molecules and manufacturing processes that pose little risk to human health or the environment.

Green chemistry, also known as sustainable chemistry, is an umbrella concept that has grown substantially since it fully emerged a decade ago. By definition, green chemistry is the design, development, and implementation of chemical products and processes to reduce or eliminate the use and generation of substances hazardous to human health and the environment.

Twelve Principles of Green Chemistry

1. Prevent waste: Design chemical syntheses to prevent waste, leaving no waste to treat or clean up.
2. Design safer chemicals and products: Design chemical products to be fully effective, yet have little or no toxicity.
3. Design less hazardous chemical syntheses: Design syntheses to use and generate substances with little or no toxicity to humans and the environment.
4. Use renewable feedstocks: Use raw materials and feedstocks that are renewable rather than depleting. Renewable feedstocks are often made from agricultural products or are the wastes of other processes; depleting feedstocks are made from fossil fuels (petroleum, natural gas, or coal) or are mined.
5. Use catalysts, not stoichiometric reagents: Minimize waste by using catalytic reactions. Catalysts are used in small amounts and can carry out a single reaction many times. They are preferable to stoichiometric reagents, which are used in excess and work only once.
6. Avoid chemical derivatives: Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
7. Maximize atom economy: Design syntheses so that the final product contains the maximum proportion of the starting materials. There should be few, if any, wasted atoms.
8. Use safer solvents and reaction conditions: Avoid using solvents, separation agents, or other auxiliary chemicals. If these chemicals are necessary, use innocuous chemicals.
9. Increase energy efficiency: Run chemical reactions at ambient temperature and pressure whenever possible.
10. Design chemicals and products to degrade after use: Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
11. Analyze in real time to prevent pollution: Include in-process real-time monitoring and control during syntheses to minimize or eliminate the formation of byproducts.
12. Minimize the potential for accidents: Design chemicals and their forms (solid, liquid, or gas) to minimize the potential for chemical accidents including explosions, fires, and releases to the environment.

Green terminology

In many countries the word “green” is associated with political parties primarily focused on environmental issues. In the United States, green symbolizes the color of money. Therefore, in areas that use the U.S. Dollar as currency, green carries a connotation of money, wealth, and capitalism. The flag of Libya is entirely green, the only current national flag of a single color. Green is considered the traditional color of Islam, likewise because of its association with nature. Green is a symbol of Ireland, which is often referred to as “the Emerald Isle” (Green represents also St. Patrick’s Day). The color is particularly identified with the republican and nationalist traditions in modern times in balance with the Protestant orange. Green is thought to be an unlucky color in British and British-derived cultures, where green cars, wedding dresses, and theatre costumes are to symbolize hope. In the Roman Catholic church, green is a traditional color symbolizing hope and the tree of life. The color green is often used as a symbol of sickness. In Japan, green indicates safety and luxury. In the Russian language, green is synonymous with “not ripe.”Green chemistry is a way of bringing back the perspective that chemicals aren’t all bad. Of reminding citizens that chemistry is the very basis of the social and economic life of virtually all industrialized nations. Everything around us is a chemical. There are hazardous and toxic chemicals, but also a lot of chemical wonders. So we’re trying, through green chemistry, to put chemistry in a very positive light: to show that it can actually be used to solve even our most pressing environmental issues, through the development of alternative technologies. Chemists have the knowledge to design chemical molecules and manufacturing processes that pose little risk to human health or the environment.

History of green chemistry

Green chemistry is a science-based, nonregulatory, economically driven approach toward sustainable development that has grown substantially since the concept fully emerged a decade ago. A key event that generated broad interest in sustainable development was the release of the 1987 United Nations report “Our Common Future.” In the report, sustainable development is defined as development that meets the needs of the present without compromising the ability of future generations to meet their own needs.

In the U.S., interest in green chemistry began in earnest with the passage of the Pollution Prevention Act of 1990, which was the first environmental law to focus on preventing pollution at the source rather than dealing with remediation or capture of pollutants–the so-called end-of-the-pipe solution. The new law led the Environmental Protection Agency to establish its Green Chemistry Program in 1991 within the Office of Pollution Prevention & Toxics. The term “green chemistry” was coined and first defined at that time by EPA’s Paul T. Anastas, an organic chemist who is now at the White House Office of Science & Technology Policy.EPA has since collaborated with academia, industry, and other government agencies to promote the use of chemistry to develop new technologies for pollution prevention. One outcome of these collaborative efforts was the establishment in 1995 of the Presidential Green Chemistry Challenge Awards (C&EN, July 2, page 24). The awards were created as a competitive effort to promote and recognize the development of environmentally benign chemical products and manufacturing processes. National green chemistry awards also have been established in the U.K., Australia, Italy, and Germany.

Another important event that has rallied proponents of green chemistry was the development of the 12 Principles of Green Chemistry by Anastas and chemistry professor John C. Warner of the University of Massachusetts, Boston.

A third key result of early efforts in green chemistry is the Green Chemistry Institute (GCI). The institute was originally organized on the Internet as a virtual nonprofit organization in May 1997 by a group of representatives from industry, academia, national labs, and other organizations. GCI’s mission is to facilitate industry-government partnerships with universities and national laboratories to develop economically sustainable clean-production technologies. GCI now has affiliate chapters in 17 countries.

“One of the issues focused on at GCI is the evolution of environmental science,” GCI Director Dennis L. Hjeresen noted. “During the past 10 to 15 years, there has been a tremendous growth in understanding in the individual disciplines of environmental science.”

But much more work will be needed in the coming years to address growing natural resource needs, Hjeresen pointed out. “A question GCI will try to address is how to put green chemistry higher on the agenda than just in the academic realm to make it a viable tool for everyone.”

GCI formed an alliance with the American Chemical Society at the beginning of this year, following efforts by Hjeresen and ACS Immediate Past-President Daryle H. Busch to increase ACS’s role in addressing the theme of chemistry and the environment. GCI has established an office at ACS headquarters in Washington, D.C., and ACS is providing core funding for the institute.

One person in the thoughts of many attendees at CHEMRAWN XIV was the late Joseph J. Breen, who died from pancreatic cancer in July 1999. Often referred to as the “heart and soul of green chemistry,” Breen had a 20-year career at EPA working in the Office of Pollution Prevention and Toxics before he retired.
difference between green chemistry and environmental chemistry

Both areas of study seek to make the world a better place.The two are complimentary to each other.Environmental science identifies sources ,elucidates,mechanisms and quantifies problems in the earth’s environment.Green chemistry seeks to solve these problems by creating alternative safe technologies.Green chemistry is not environmental chemistry. Green chemistry targets pollution prevention at the source, during the design stage of a chemical product or process,and thus prevents pollution before it begins.

conclution

Green is a strong color. Green is the color of chlorophyll, and green is the color of money. Being green has long been a battle cry of environmental activists, and being green has become an important marketing tool for businesses.This is a field aimed at large global problems such as climate change, energy consumption, and management of our water resources and for chemists, it is becoming increasingly important to be green by applying the principles of green chemistry to all faces of the chemical sciences: basic and applied research, production, and education.