Presentation1

GREEN CHEMISTRYGREEN CHEMISTRY

DEFINITIONDEFINITION Green Chemistry is the utilisation of a set of principles that reduces or eliminates the Green Chemistry is the utilisation of a set of principles that reduces or eliminates the

use or generation of hazardous substances in the design, manufacture and use or generation of hazardous substances in the design, manufacture and application of chemical productsapplication of chemical products . .

GREEN CHEMISTRY IS ABOUTGREEN CHEMISTRY IS ABOUT• Waste Minimisation at SourceWaste Minimisation at Source• Use of Catalysts in place of ReagentsUse of Catalysts in place of Reagents• Using Non-Toxic ReagentsUsing Non-Toxic Reagents• Use of Renewable ResourcesUse of Renewable Resources• Improved Atom EfficiencyImproved Atom Efficiency• Use of Solvent Free or Recyclable Environmentally Benign Use of Solvent Free or Recyclable Environmentally Benign

Solvent systemsSolvent systems

Green Chemistry Is Green Chemistry Is About...About...

Cost

Waste

Materials

Hazard

Risk

Energy

Chemistry is undeniably a very Chemistry is undeniably a very prominent part of our daily lives.prominent part of our daily lives.

Chemical developments also bring Chemical developments also bring new environmental problems and new environmental problems and harmful unexpected side effects, harmful unexpected side effects, which result in the need for which result in the need for ‘greener’ chemical products.‘greener’ chemical products.

A famous example is the pesticide A famous example is the pesticide DDT.DDT.

Why do we need Green Chemistry ?Why do we need Green Chemistry ?

The 12 Principles of Green The 12 Principles of Green Chemistry (1-6)Chemistry (1-6)

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.

7 Use of Renewable Feed stocks7 Use of Renewable Feed stocksA raw material or feedstock should be renewable rather than depleting whenever A raw material or feedstock should be renewable rather than depleting whenever technically and economically practicable.technically and economically practicable.

8 Reduce Derivatives8 Reduce DerivativesUnnecessary derivatization (use of blocking groups, protection/de-protection, and Unnecessary derivatization (use of blocking groups, protection/de-protection, and temporary modification of physical/chemical processes) should be minimised or temporary modification of physical/chemical processes) should be minimised or avoided if possible, because such steps require additional reagents and can avoided if possible, because such steps require additional reagents and can generate waste.generate waste.

9 Catalysis9 CatalysisCatalytic reagents (as selective as possible) are superior to stoichiometric reagents.Catalytic reagents (as selective as possible) are superior to stoichiometric reagents.

10 Design for Degradation10 Design for DegradationChemical products should be designed so that at the end of their function they break Chemical products should be designed so that at the end of their function they break down into innocuous degradation products and do not persist in the environment.down into innocuous degradation products and do not persist in the environment.

11 Real-time Analysis for Pollution Prevention11 Real-time Analysis for Pollution PreventionAnalytical methodologies need to be further developed to allow for real-time, in-Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and control prior to the formation of hazardous substances.process monitoring and control prior to the formation of hazardous substances.

12 Inherently Safer Chemistry for Accident Prevention12 Inherently Safer Chemistry for Accident PreventionSubstances and the form of a substance used in a chemical process should be Substances and the form of a substance used in a chemical process should be chosen to minimise the potential for chemical accidents, including releases, chosen to minimise the potential for chemical accidents, including releases, explosions, and fires.explosions, and fires.

The 12 Principles of Green The 12 Principles of Green Chemistry (7-12)Chemistry (7-12)

““It is better to prevent It is better to prevent waste than to treat or waste than to treat or

cleancleanup waste after it is up waste after it is

formed”formed”

Chemical

Process

Risk = Risk = f(hazard,exposure)f(hazard,exposure)

Do we consider our level of exposure Do we consider our level of exposure and the hazard itself?and the hazard itself?

Does the dose makes the poison?Does the dose makes the poison?

““Energy requirements Energy requirements should be recognized for should be recognized for

their environmental impacts their environmental impacts and should be minimized.and should be minimized.

Synthetic methods should be Synthetic methods should be conducted at ambientconducted at ambient

pressure and temperature”pressure and temperature”

GREEN CHEMISTRY

Green Chemistry is the utilization of a set of principles that reduces or eliminates the use or generation of hazardous substances in the design, manufacture and applications of chemical products.

““A raw material of feedstock should A raw material of feedstock should be renewablebe renewable

rather than depleting wherever rather than depleting wherever technically andtechnically and

economically practical”economically practical”Non-renewable Renewable

Polyhydroxyalkanoates (PHA’s)Polyhydroxyalkanoates (PHA’s)

Prevention & Reduction

Recycling & Reuse

Treatment

Disposal

Pollution Prevention Pollution Prevention HierarchyHierarchy

Resource DepletionResource DepletionRenewable resources can be made Renewable resources can be made

increasingly viable technologically and increasingly viable technologically and economically through green chemistry.economically through green chemistry. BiomassBiomass Nanoscience & technologyNanoscience & technology SolarSolar Carbon dioxideCarbon dioxide ChitinChitin Waste utilizationWaste utilization

Law of Conservation Law of Conservation of Matterof Matter

Matter cannot be created or destroyed.Matter cannot be created or destroyed.

A candle burns and appears to be A candle burns and appears to be destroyed, but..turns into less destroyed, but..turns into less observable gas (a byproduct).observable gas (a byproduct).

EnergyEnergy

Green Chemistry will be essential inGreen Chemistry will be essential in developing the alternatives for energy developing the alternatives for energy

generation (photovoltaics, hydrogen, fuel generation (photovoltaics, hydrogen, fuel cells, biobased fuels, etc.) as well as cells, biobased fuels, etc.) as well as

continue the path toward energy efficiency continue the path toward energy efficiency with catalysis and product design at the with catalysis and product design at the forefront.forefront.

EnergyEnergy Global ChangeGlobal Change Resource Depletion Resource Depletion Food SupplyFood Supply Toxics in the EnvironmentToxics in the Environment

The major uses of GREEN The major uses of GREEN CHEMISTRYCHEMISTRY

““The use of auxiliary substances (e.g. The use of auxiliary substances (e.g. solvents,solvents,

separation agents, etc.) should be made separation agents, etc.) should be made unnecessaryunnecessary

wherever possible, and innocuous when wherever possible, and innocuous when used”used”

HeatingCoolingStirringDistillationCompressionPumping Separation

Energy Requirement(electricity)

Burn fossil fuel

CO2 toatmosphere

GLOBAL WARMING

Resource DepletionResource Depletion Renewable resources can be made Renewable resources can be made

increasingly viable technologically increasingly viable technologically and economically through green and economically through green chemistry.chemistry.

Biomass

Nanoscience

Solar

Carbondioxide

Waste utilization

Poly lactic acid (PLA) for plastics Poly lactic acid (PLA) for plastics productionproduction

EnergyEnergy

The vast majority of the energy The vast majority of the energy generated in the world today is generated in the world today is from non-renewable sources that from non-renewable sources that damage the environment.damage the environment. Carbon dioxideCarbon dioxide Depletion of Ozone layer Depletion of Ozone layer Effects of mining, drilling, etcEffects of mining, drilling, etc ToxicsToxics

ConclusionConclusion

Green chemistry Not a solution

to all environmental problems But the most fundamental approach to preventing pollution.

SummarySummarySummarySummary

• • Green Chemistry provides a technical Green Chemistry provides a technical solution tosolution to

many environmental problemsmany environmental problems• • Effective due to design stage efforts, starting Effective due to design stage efforts, starting

at theat themolecular level lets you design out the molecular level lets you design out the

hazardoushazardousproperties and design in environmentally properties and design in environmentally

appropriateappropriatefeatures.features.

• • A systematic approach can ensure effectiveA systematic approach can ensure effectiveapplication.application.

• • Why Green Chemistry? Because we can….Why Green Chemistry? Because we can….

Thank you