Green Chemistry

Green Chemistry. Mireli Gonzalez & Kyla Encalada.

Interesting Facts Principles of Green Chemistry What is green Chemistry? Applications/Examples of Green Chemistry Historical Background.

WHAT IS GREEN CHEMISTRY?. 01.

Green chemistry deals with how to prevent harming the environment by improving chemical processes and manufacturing techniques..

It also seeks to reduce the waste of chemicals used in the reaction, reduce waste of energy and increase the efficiency of the processes. Green Chemistry strives for sustainability by developing chemical products that are safe for both human health and the environment, using industrial procedures that reduce or eliminate the usage of hazardous substances; establishing more efficient processes that reduce waste production and the amount of nonrenewable energy produced..

HISTORICAL BACKGROUND. 02.

Green chemistry was developed as a response to the pollution prevention act in 1990. This is the US environmental law stating that the first choice for preventing pollution is to design industrial processes that do not lead to waste production. This is the approach of Green Chemistry. This began in significant part with industrialization, when the assembly belt catapulted in mass production, transportation between countries became more attainable, and products transitioned from being manufactured from local parts to being developed from parts from everywhere in the world..

[Audio] . Accumulation of mass manufacturing; consequently, there was a concentration of mass waste For years, contaminants were emitted into the environment with no awareness that these substances/chemicals were hazardous and that dumping them without correct treatment procedures would eventually lead to contaminants in air, homes, food, and, ultimately, humanity. For example; pesticides contaminate surface water, groundwater, and soil, as well as infect non-target vegetation. When the risks of chemicals created in society became known, significant damage had already been done..

12 PRINCIPLES OF GREEN CHEMISTRY. 03.

WASTE PREVENTION. 2. ATOM ECONOMY. 3. LESS HAZARDOUS CHEMICAL SYNTHESIS.

10. NATURE OF BREAKDOWN OF PRODUCTS. 11.MONITORING TO PREVENT POLLUTION.

WASTE PREVENTION. It is ideal to reduce waste instead of repairing it after it has occurred. Plan ahead of time to reduce waste at every stage..

2. ATOM ECONOMY. Synthesis procedures should make use of as many of the materials used in the process as possible and incorporate them into the necessary result. The atomic economy should be as near to 100% as possible. Reduce waste at the molecular level by increasing the number of atoms included into the final result from all reagents..

3. LESS HAZARDOUS CHEMICAL SYNTHESIS. The impact of reactants, products, and catalysts on the environment and life should be kept to a minimum. Create chemical reactions and synthetic pathways that are as safe and practical. Take into account the dangers of all substances handled throughout the reaction, including waste..

4 . SAFER CHEMICAL PRODUCTS. The effectiveness of the products should not be diminished at the same time that their potential damage is reduced. Directly reduce toxicity by molecular design. Throughout the design phase, predict and analyze elements such as physical attributes, toxicity, and environmental fate..

5 . SAFER SOLVENT AND OTHER AGENTS. Reactions should be designed in such a way that toxic solvents, catalysts, and chemicals used in separation procedures are avoided or used as little as possible. For each stage, use the safest solvent available. Reduce the overall amount of solvents and other substances utilized, as these account for a major portion of total waste generated..

6.MINIMUM ENERGY REQUIREMENTS. The least amount of energy possible should be used. If possible, the reactions should be carried out at room temperature. The heat produced by exothermic reactions should be utilised for another purpose rather than being discharged into the environment. (For example, hot water) Choose the chemical method that requires the least amount of energy. Heat and cold, as well as pressured and vacuum environments, should be avoided..

7 . USE OF RENEWABLE RAW MATERIALS. Instead of diminishing natural resources, raw materials and feedstock should be renewable. A feedstock is a natural resource (or a substance that has been lightly processed) that is used as the starting material for a chemical process. Use chemicals derived from renewable sources rather than equivalent compounds derived from petrochemical sources..

8 .REDUCE DERIVATIVES. When a material is synthesized in multiple phases, certain compounds (blocking groups) are utilized to prevent reactive functional groups from interacting in undesirable ways. The blocking groups are subsequently retracted. Avoid using derivatives to cut down on reaction steps, resources needed, and waste generated..

9. USE OF CATALYST. Because the reaction occurs at a lower temperature, the use of a catalyst reduces energy consumption. The more specialised the catalyst for a specific reaction is, the less likely it is to produce undesirable byproducts..

10. NATURE OF BREAKDOWN OF PRODUCTS. Products should be intended to decay in the environment into a harmless component. The breakdown products should not be expected to exist in the environment for an extended period of time. Make certain that neither the substances nor their degradation products are hazardous, bioaccumulative, or ecologically persistent..

11 . MONITORING TO PREVENT POLLUTION. Each stage in a chemical synthesis should be monitored for the presence of pollutants, and techniques to regulate the development of these pollutants or their release into the environment..

12. MINIMISE CHEMICAL ACCIDENTS. The dangers posed by reactants and products must be considered. Choose and create chemical techniques that are safer and, by definition, reduce the likelihood of incidents. Know the potential dangers and evaluate them ahead of time..

APPLICANTS/ EXAMPLES OF GREEN CHEMISTRY. 04.

Maleic anhydride is used to manufacture polyester resin and paints. First by heating benzene with oxygen in the presence of a catalyst. Now manufactured from butane Replacing lead in paint with safe alternatives, and replacing it tetraethyl lead with less toxic additives (e.g lead free gasoline).

Chemical Foams to fight fires- Million of tons of chemical fire fighting foams used worldwide have discharged toxic substances into the environment, contaminating and depleting the ozone layer. A new foam called Pyrocool FEF has now been invented to put out fires effectively without producing the toxic substances found in other fire-fighting materials ..

Chemicals for Dry Cleaning- Perchloroethylene (“perc”) is the solvent most widely used in dry cleaning clothing. Perc is suspected of causing cancer and its disposal can contaminate groundwater. Liquid CO2 can be used as a safer solvent if a wetting agent is used with it to dissolve grease. This method is now being used commercially by some dry cleaners..

INTERESTING FACTS. 05.

Algae can be used to produce fuels Some scientists have suggested that algae should be grown in huge quantities in the oceans to absorb carbon dioxide and reduce global warming Algae could be grown in controlled environments using the nutrients (nitrate and phosphates) from the waste water from the sewage works..

The Cuyahoga River in Ohio became so polluted that it caught fire ..

A plant accident in Bhopal, India, released methyl isocyanate. Nearly 4,000 people died..

An accidental release of chemicals, including dioxin, in Seveso, Italy in 1976 resulted in the deaths of farm animals and long-term health problems for many local residents..

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