Skew symmetric matrix and Green chemistry: Difference between pages
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'''Green Chemistry''' is the design of chemical products and processes that reduce or eliminate the use and generation of hazardous substances. Whereas [[environmental chemistry]] is the chemistry of the natural environment, and of pollutant chemicals in nature, green chemistry seeks to reduce and prevent [[pollution]] at source. In [[1990]] the [[Pollution Prevention Act]] was passed. This act helped create a ''modus operandi'' for dealing with pollution in an original and innovative way.
Paul Anastas and John C Warner of the [[Environmental Protection Agency|EPA]] have developed 12 principles to green chemistry [http://www.epa.gov/greenchemistry/principles.html]:
# ''Prevent waste:'' Design [[chemical synthesis|chemical syntheses]] to prevent [[waste]], leaving no waste to [[waste treatment|treat]] or clean up.
# ''Design safer [[chemical]]s and products:'' Design chemical products to be fully effective, yet have little or no [[toxicity]].
# ''Design less hazardous chemical syntheses:'' Design syntheses to use and generate substances with little or no toxicity to humans and the [[environment (biology)|environment]].
# ''Use [[renewable]] [[feedstock]]s:'' Use [[raw materials]] and feedstocks that are renewable rather than [[depletion|depleting]]. Renewable feedstocks are often made from [[agriculture|agricultural]] products or are the wastes of other processes; depleting feedstocks are made from [[fossil fuels]] ([[petroleum]], [[natural gas]], or [[coal]]) or are [[mining|mined]].
# ''Use [[catalyst]]s, not [[stoichiometric]] [[reagent]]s:'' Minimize waste by using [[catalysis|catalytic reaction]]s. [[Catalyst]]s 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.
# ''Avoid chemical derivatives:'' Avoid using blocking or protecting groups or any temporary modifications if possible. Derivatives use additional reagents and generate waste.
# ''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.
# ''Use safer [[solvent]]s and [[reaction]] conditions:'' Avoid using solvents, [[separation of mixture|separation]] agents, or other auxiliary chemicals. If these chemicals are necessary, use innocuous chemicals. If a solvent is necessary, water is usually the best medium.
# ''Increase [[energy]] [[efficiency]]:'' Run chemical reactions at [[ambient temperature]] and [[atmospheric pressure|pressure]] whenever possible.
# ''Design chemicals and products to [[biodegradation|degrade]] after use:'' Design chemical products to break down to innocuous substances after use so that they do not accumulate in the environment.
# ''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.
# ''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.
In 2005 [[Ryoji Noyori]] identified three key developments in green chemistry: use of [[supercritical carbon dioxide]] as green solvent, [[aqueous]] [[hydrogen peroxide]] for clean [[oxidation]]s and the use of hydrogen in [[asymmetric synthesis]] {{ref|1}}. Examples of applied green chemistry are [[Supercritical water oxidation]], [[On water reaction]]s and [[dry media reaction]]s.
For similar initiatives in other fields, see also [[Green computing]].
==External links==
*[http://www.epa.gov/greenchemistry/whats_gc.html EPA Green Chemistry Website]
*[http://www.epa.gov/greenchemistry/docs/general_fact_sheet.pdf EPA Green Chemistry Fact Sheet]
*[http://www.chemistry.org/greenchemistryinstitute Green Chemistry Institute]
*[http://www.usatoday.com/news/science/2004-11-21-green_x.htm Green chemistry takes root (USA Today)]
*[http://www.greenchemistry.uml.edu Green Chemistry PhD Program at University of Massachusetts Lowell]
*[http://darkwing.uoregon.edu/~greenlab/index.html Green Chemistry Experiments for Education, University of Oregon]
== References ==
* {{note|1}}. ''Pursuing practical elegance in chemical synthesis'' Ryoji Noyori Chemical Communications, 2005, (14), 1807 - 1811 [http://www.rsc.org/publishing/journals/CC/article.asp?doi=b502713f Abstract]
[[Category:Environmental chemistry]]
[[it:Chimica verde]]
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[[pl:Zielona chemia]]
[[zh:绿色化学]]
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