Green chemistry may be defined as the design of new chemical products and processes, (or making improvements in already existing compounds and processes), so as to reduce or eliminate the use and generation of hazardous substances, making them less harmful to human health and environment. By reducing or eliminating the use or generation of these hazardous substances, chemists can greatly reduce the risk to human health and environment.
Green chemistry is a highly effective approach to pollution prevention as it applies innovative scientific solutions to real world environmental problems. Chemical technologies are looked at during their design, manufacture and use as chemical process and products having broad application in industry. The substances include feedstock, reagents, solvents, products and by products.Green chemistry encompasses all aspects and types of chemical process including synthesis, catalysis, analysis, monitoring, separations and reaction conditions, which reduce or eliminate the use or generation of hazardous substances.
Green chemistry technologies can be categorized into one or more of the following focus areas.- The use of alternative synthetic pathways for green chemistry.
- The use of alternative reaction conditions for green chemistry.
- The design of chemicals that are less toxic than current alternatives or inherently safer with regard to accident potential.
The phrase green chemistry was used by the scientists in USA, shortly after the passing of the USA Prevention of pollution act 1990. A series of grants were made available by the US Government to promote the field of green chemistry by research into pollution prevention in the design and synthesis of chemicals. The green chemistry programme is now a world wide effort of many governments, academia, scientific societies, industry, trade organizations, small business, non government organizations, research centers and other government agencies to promote the use of chemistry for pollution prevention through completely voluntary, non-regulatory partnerships.
Over the past several years, international efforts in the field of green chemistry have greatly increased the hopes of combating the most pressing environmental problems such as water pollution, global warming and ozone depletion, etc. International Union of Pure and Applied Chemistry (IUPAC) and the management organization of Green Chemistry Institute have been working in collaboration with industry and other research institutions world wide, to help solve these pollution and other related problems.Collective efforts in the field of green chemistry have made tremendous impacts on several industrial sectors in recent years. Some of the achievements in this field are as follows:
Development of dense-phase carbon dioxide
This is a recently developed chemical product that displays remarkable characteristics. It is a super critical carbon dioxide that displays an ability to clean everything from the plutonium pits to semiconductor wafer as well as clothes. It can also be used as recyclable solvent and finds number of applications in food industry. Future possible uses of dense-phase carbon dioxide include making cement stronger and also in reducing pollution emission from coal plants.
Development of fuel cells
These cells are based on methanol oxygen fuels and are another significant achievement of the green chemistry programme. These cells are for use in cellular phones and last for the full lifetime of the phone.
Development of oxidative cracking process
This is a development that helps in production of ethylene, a major industrial raw material. This process saves about 13 trillion British Thermal Units of natural gas over the conventional hydrocarbon cracking process. It also reduces carbon dioxide emissions by about four tonnes annually.
Thus, green chemistry program recognizes and promotes fundamental breakthroughs in chemistry that accomplish pollution prevention in a cost effective manner.