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ABHISHEK JAGUESSAR
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GREEN CHEMISTRY
DEFINITIONGreen Chemistry is the utilisation of a set of principles that reducesor eliminates the use or generation of hazardous substances in thedesign, manufacture and application of chemical products .
GREEN CHEMISTRY IS ABOUT Waste Minimisation at Source
Use of Catalysts in place of Reagents
Using Non-Toxic Reagents Use of Renewable Resources
Improved Atom Efficiency
Use of Solvent Free or Recyclable EnvironmentallyBenign Solvent systems
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Green Chemistry Is About...
Cost
Waste
Materials
Hazard
Risk
Energy
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Chemistry is undeniably a very prominentpart of our daily lives.
Chemical developments also bring newenvironmental problems and harmfulunexpected side effects, which result inthe need for greener chemical products.
A famous example is the pesticide DDT.
Why do we need Green Chemistry ?
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Green chemistry looks at pollutionprevention on the molecular scale and is an
extremely important area of Chemistry due tothe importance of Chemistry in our worldtoday and the implications it can show on ourenvironment.
The Green Chemistry program supports theinvention of more environmentally friendlychemical processes which reduce or eveneliminate the generation of hazardous
substances. This program works very closely with the
twelve principles ofGreen Chemistry.
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1. PreventionIt is better to prevent waste than to treat or clean up waste after it has been created.
2. Atom EconomySynthetic methods should be designed to maximise the incorporation of all materialsused in the process into the final product.
3. Less Hazardous Chemical SynthesisWherever practicable, synthetic methods should be designed to use and generatesubstances that possess little or no toxicity to people or the environment.
4. Designing Safer ChemicalsChemical products should be designed to effect their desired function while minimisingtheir toxicity.
5. Safer Solvents and AuxiliariesThe use of auxiliary substances (e.g., solvents or separation agents) should be madeunnecessary whenever possible and innocuous when used.
6. Design for Energy EfficiencyEnergy requirements of chemical processes should be recognised for their environmentaland economic impacts and should be minimised. If possible, synthetic methods should beconducted at ambient temperature and pressure.
The 12 Principles of Green Chemistry (1-6)
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7 Use of Renewable FeedstocksA raw material or feedstock should be renewable rather than depleting whenever technically andeconomically practicable.
8 Reduce DerivativesUnnecessary derivatization (use of blocking groups, protection/de-protection, and temporary modification ofphysical/chemical processes) should be minimised or avoided if possible, because such steps requireadditional reagents and can generate waste.
9 CatalysisCatalytic reagents (as selective as possible) are superior to stoichiometric reagents.
10 Design for DegradationChemical products should be designed so that at the end of their function they break down into innocuousdegradation products and do not persist in the environment.
11 Real-time Analysis for Pollution PreventionAnalytical methodologies need to be further developed to allow for real-time, in-process monitoring andcontrol prior to the formation of hazardous substances.
12 Inherently Safer Chemistry for Accident PreventionSubstances and the form of a substance used in a chemical process should be chosen to minimise thepotential for chemical accidents, including releases, explosions, and fires.
The 12 Principles of Green Chemistry (7-12)
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It is better to prevent wastethan to treat or clean
up waste after it is formed
ChemicalProcess
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Classic Route to Ibuprofen
Ac2O
AlCl3
C OC H3
HCl, AcOH, Al W aste
ClCH2CO
2Et
NaOEt
OEtO
2C
HCl
H2O / H+
O HC
AcOH
NH2O H
O HNN
H2O / H+
HO2C
NH3
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Hoechst Route To Ibuprofen
O
HF
AcOH
Ac2O
H2
/ Ni
OH
CO, Pd
HO2C
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The use of auxiliary substances (e.g. solvents,separation agents, etc.) should be made
unnecessarywherever possible, and innocuous when used
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Energy requirements should be
recognized for their environmentalimpacts and should be minimized.
Synthetic methods should be
conducted at ambientpressure and temperature
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Heating
CoolingStirring
Distillation
Compression
Pumping
Separation
Energy Requirement
(electricity)Burn fossil
fuel
CO2 to
atmosphere
GLOBAL
WARMING
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A raw material of feedstock should be
renewablerather than depleting wherevertechnically and
economically practical
Non-renewable Renewable
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Resource Depletion
Renewable resources can be madeincreasingly viable technologicallyand economically through greenchemistry.
Biomass
Nanoscience
Solar
Carbondioxide
Waste utilization
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Poly lactic acid (PLA) for plastics production
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Polyhydroxyalkanoates (PHAs)
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Energy
The vast majority of the energygenerated in the world today isfrom non-renewable sources that
damage the environment.
Carbon dioxide
Depletion of Ozone layer Effects of mining, drilling, etc
Toxics
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Energy
Green Chemistry will be essential in
developing the alternatives for energygeneration (photovoltaics, hydrogen, fuel
cells, biobased fuels, etc.) as well as
continue the path toward energy efficiencywith catalysis and product design at the
forefront.
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Global Change
Concerns for climate change,oceanic temperature, stratospheric
chemistry and global distillation canbe addressed through thedevelopment and implementation of
green chemistry technologies.
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Resource Depletion
Due to the over utilization of non-
renewable resources, natural
resources are being depleted at anunsustainable rate.
Fossil fuels are a central issue.
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Resource Depletion
Renewable resources can be madeincreasingly viable technologically andeconomically through green chemistry.
Biomass Nanoscience & technology
Solar
Carbon dioxide
Chitin
Waste utilization
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Food Supply
While current food levels are sufficient,distribution is inadequate
Agricultural methods are unsustainable Future food production intensity is
needed.
Green chemistry can address manyfood supply issues
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Food Supply
Green chemistry is developing: Pesticides which only affect target
organisms and degrade to innocuousby-products.
Fertilizers and fertilizer adjuvants thatare designed to minimize usage while
maximizing effectiveness. Methods of using agricultural wastes
for beneficial and profitable uses.
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Toxics in the
EnvironmentSubstances that are toxic to humans, thebiosphere and all that sustains it, arecurrently still being released at a cost of
life, health and sustainability.
One of green chemistrys greateststrengths is the ability to design for
reduced hazard.
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Prevention & Reduction
Recycling & Reuse
Treatment
Disposal
Pollution Prevention Hierarchy
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Conclusion
Green chemistry Not a solution
to all environmental problems Butthe most fundamental approach to
preventing pollution.
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Thank you