green chemistry by abhishek jaguessar

8/4/2019 Green Chemistry by Abhishek Jaguessar

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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

green chemistry by abhishek jaguessar

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