Environment Green Chemistry

1. Environment Green Chemistry www.assignmentpoint.com

2. 1.1. Chemistry is Good • All matter is chemical; we are chemical • The human body is a complex chemical factory • Green Chemistry seeks to present a body of chemical knowledge from the most fundamental level within a framework of the relationship of chemical science to human beings, their surroundings, and their environment. • Green chemistry is the practice of chemistry in a manner that maximizes its benefits while eliminating or at least greatly reducing its adverse impacts www.assignmentpoint.com

3. Good Things from Chemistry • Pharmaceuticals that have improved health and extended life • Fertilizers that have greatly increased food productivity • Semiconductors that have made possible computers and other modern electronic devices • The Downside of Chemistry • Pollutants • Toxic substances • Nonbiodegradable plastic containers • These have resulted in harm to the environment www.assignmentpoint.com

4. Major Categories of Chemistry • Inorganic chemistry deals with materials composed of most elements other than carbon (and includes a few carbon compounds) • Organic chemistry deals with carbon-containing materials, most having carbon-carbon bonds • Physical chemistry involves the underlying theory and physical phenomena that explain chemical processes • Biochemistry is the chemistry of living processes • Analytical chemistry is the identification and quantification of chemical species, often at very low levels www.assignmentpoint.com

5. Chemists and Chemistry are Part of the Solution • Chemistry is required to deal with environmental problems and challenges to sustainability • Of all professionals, chemists are the best qualified to understand environmental problems from the misuse of chemistry • The practice of environmentally beneficial chemistry is not a burden, but rather an opportunity that challenges human imagination and ingenuity www.assignmentpoint.com

6. 1.2. THE ENVIRONMENT AND THE FIVE ENVIRONMENTAL SPHERES www.assignmentpoint.com

7. The Atmosphere • Very thin, most within several kilometers of Earth’s surface • Provides oxygen for animals and other organisms, carbon dioxide and nitrogen for plants • Vital protective function • Stratospheric ozone protects against harmful ultraviolet • Stabilizes Earth’s temperature by re-absorbing outgoing heat as infrared radiation • Conduit for fresh water by way of the hydrologic cycle www.assignmentpoint.com

8. The Hydrosphere • More than 97% in oceans • Most of the remaining fresh water is ice and snow in polar ice caps and glaciers • Small fraction of water in atmospheric water vapor • Fresh water on the surface in lakes, reservoirs, and streams and as groundwater in underground aquifers www.assignmentpoint.com

9. The Biosphere • All living organisms • Most found in a very thin layer at the interface of the geosphere and atmosphere and in the hydrosphere • Involved with the geosphere, hydrosphere, atmosphere and even anthrosphere through biogeochemical cycles • Biogeochemical cycles involve important life elements including carbon, nitrogen, and phosphorus www.assignmentpoint.com

10. The Anthrosphere • Strong interactions with other environmental spheres • Cultivation of land modifies the geosphere • Diversion and use of water affects the hydrosphere • Emission of particles, acid gases, organics, greenhouse warming carbon dioxide • Perturbation of biogeochemical cycles • Entering anthropocene era www.assignmentpoint.com

11. Chemistry of the Geosphere and Soil www.assignmentpoint.com

12. 1.4. Environmental Pollution • Awareness from • Silent Spring, Rachel Carson, 1962 • Approximately 10,000 deformed children from thalidomide • Visible air pollution • “Dead” bodies of water • Love Canal around 1970 www.assignmentpoint.com

13. 1.5. What is Green Chemistry? Green chemistry is the sustainable practice of chemical science and manufacturing within a framework of industrial ecology in a manner that is sustainable, safe, and non-polluting, consuming minimum amounts of energy and material resources while producing virtually no wastes. www.assignmentpoint.com

14. Green Chemistry is Sustainable • Economic: At a high level of sophistication, green chemistry normally costs less in conventional economic terms (as well as environmental costs) than chemistry as it is traditionally practiced • Materials: By efficiently using materials, maximum recycling, and minimum use of virgin raw materials, green chemistry is sustainable with respect to materials • Waste: By reducing insofar as possible, or even totally eliminating their production, green chemistry is sustainable with respect to wastes www.assignmentpoint.com

15. 1.6. Green Chemistry and Synthetic Chemistry Synthetic chemistry involves finding ways to make new chemicals and new ways to make known chemicals • Use existing feedstocks, but make them by more environmentally benign processes • Use other feedstocks made by environmental benign processes www.assignmentpoint.com

16. Yield and Atom Economy (2) www.assignmentpoint.com

17. 1.7. Reduction of Risk: Hazard and Exposure Risk = F{hazardexposure} • Reduced exposure: The hazard remains, but exposure to it is reduced, such as by wearing safety goggles around an eye hazard (a command and control approach) • Reduced hazard: The hazard is diminished or eliminated at its source; measures still may be taken to reduce exposure to remaining hazard • Hazard exposure is less costly because costs of protective measures may be reduced www.assignmentpoint.com

18. 1.8. The Risks of No Risks • Refusal to take any risks can cause scientific and economic progress to stagnate • Example: Refusal to take the risks of thermally treating wastes (hazardous waste incineration) can lead to waste accumulation, or important industrial processes making the waste may be ceased • Example: Unwillingness to take risks involved with nuclear energy can lead to greenhouse warming from using fossil fuels or to economic stagnation from energy shortages www.assignmentpoint.com

19. 1.9. Waste Prevention • Costs of engineering controls, regulatory compliance, personnel protection, wastewater treatment, and safe disposal of hazardous solid wastes have become high costs of doing business • Waste prevention applying the principles of green chemistry and industrial ecology is a much better approach www.assignmentpoint.com

20. 1.10. Twelve Principles of Green Chemistry (1) It is better to prevent waste than to treat or clean up waste after it is formed Synthetic methods should be designed to maximize the incorporation of all materials used in the process into the final product Synthetic processes should avoid use and generation of toxic and environmentally damaging substances Chemical products should be as effective as possible but with minimum toxicity Auxiliary substances, such as solvents and separation agents should be avoided or should be as innocuous as possible Energy requirements should be low; extreme temperatures and pressures should be avoided www.assignmentpoint.com

21. Twelve Principles of Green Chemistry (2) 7. Raw materials should be from renewable sources Derivatization for blocking groups protection and property modification should be avoided Catalytic reagents should be used when possible because of their specificity and minimum amounts required Chemical products should be designed so that at the end of their lifetime they readily break down to harmless products The best analytical and monitoring capabilities should be employed to allow real-time, in-process monitoring that prevents formation of hazardous substances Substances and forms of them used should be chosen to avoid potentially harmful releases, fires, and explosions www.assignmentpoint.com

22. 1.11. Some Things to Know About Chemistry Before You Even Start • Fewer than 100 naturally occurring elements, about 30 made by humans • All elements composed of chemically identical atoms • Each atom of a particular element has the same number of positively charged protons in its nucleus equal to the atomic number of the element. • Electrons are in motion around the nucleus; a neutral atom has equal numbers of electrons and protons • Each element has a chemical symbol (nitrogen, N, sodium, Na, for Latin name natrium • The average mass of all atoms of an element is its atomic mass www.assignmentpoint.com

23. 1.13. Chemical Reactions • A chemical reaction occurs when chemical bonds are broken and formed and atoms are exchanged to produce chemically different species. CH4 + 2O22H2O + CO2 Reactants Products Yields Above is a chemical equation for the reaction of methane with oxygen. It is balanced because it has the same number of each kind of atom (1 C, 4H, 4O) among both the reactants and products. www.assignmentpoint.com

24. 1.14. The Nature of Matter and States of Matter • Most matter consists of mixtures composed of two or more chemically distinct substances • A homogeneous mixture, such as air, consists of substances mixed at the molecular level that cannot be separated by mechanical means. • A heterogeneous mixture is composed of two or more substances that are visibly distinct and can be separated by mechanical means. • Mixtures are important in green chemistry; the separation of components of wastes and byproducts is often a significant expense in recycling www.assignmentpoint.com