“ Chemistry has an important role to play in achieving a sustainable civilization on earth.” — Dr. Terry Collins, Professor of Chemistry Carnegie Mellon.

“ Chemistry has an important role to play in achieving a sustainable

civilization on earth.”

— Dr. Terry Collins, Professor of ChemistryCarnegie Mellon University

WHAT IS A SUSTAINABLE CIVILIZATION?

CONSIDER THIS QUESTION FROM SEVERAL VIEWPOINTS:

• The environment and human health.

• A stable economy that uses energy and resources efficiently.

• Social and political systems that lead to a just society.

TO UNDERSTAND THE ROLE OF CHEMISTRY IN SUSTAINABILITY,

WE WILL LOOK AT THE FIRST TWO POINTS…

• The environment and human health.

• A stable economy that uses energy and resources efficiently.

IN A SUSTAINABLE CIVILIZATION…

Technologies used for production of needed goods are

not harmful to the environment or to human health.

Renewable resources (such as plant-based substances

or solar energy) are used rather than those, like fossil

fuels, that will eventually run out.

IN A SUSTAINABLE CIVILIZATION…

At the end of their use, materials are recycled if they

are not biodegradable (easily broken down into

harmless substances in the environment).

Manufacturing processes are either designed so as not to

produce waste products,

– OR –

Waste products are recycled or biodegradable.

IN A SUSTAINABLE CIVILIZATION…

WHILE WE HAVE MADE SOME PROGRESS IN ACHIEVING THESE GOALS, WE STILL HAVE A LONG WAY TO GO…

Mountains of solid waste are piling up—particularly in

industrialized nations.

Air and water pollution continue to be problems in many

places.

BUT HOW CAN CHEMISTRY HELP US

TO ACHIEVE A SUSTAINABLE CIVILIZATION?

First, let’s consider chemistry’s benefits…

The chemical industry produces many products that improve our lives

and upon which we depend.

BENEFITS OF CHEMICAL INDUSTRY:

Antibiotics and other medicines

Fertilizers, pesticides

Plastics

Nylon, rayon, polyester, and other synthetic materials

Gasoline and other fuels

Water purification

Why Green Chemistry ?

SOME WELL-PUBLICIZED INCIDENTS FROM THE PAST FEW DECADES…

1. Bhopal disaster, 02-12-1984, methyl isocyanate – SEVEN Nearly 25,000 people died.

SOME WELL-PUBLICIZED INCIDENTS FROM THE PAST FEW DECADES…

2. Dioxin episodes during vietnam War the U.S. Military sprayed 42

million liltre of herbicide ‘Agent Orange’ (2,4-dichlorophenoxyacetic acid (2,4 D)+ 2,4,5-trichlorophenoxyacetic acid(2,4,5 D)), which was contaminated with dioxin to destroy the forest cover.Dioxan created a havoc in the life of the millions of victims of the war and other residents of the areaDioxins most important carcinogenic, number of them suffered with skin tumorsAbsorbed to the skin Children born to such women were deformed with low IQ and or mentally retarded

2. In Seveso- Italy, (1976) Roche Holding Ltd.releasing chemicals containing dioxin 37,000 were affected.

Thalidomide scare: 1961 Europe Lessen the effects of nausea & vomiting (morning

sickness) during pregnancy

Children of the women suffeed birth defects-missing or deformed limbs

Love Canal disaster

NY – a chemical and plastic company had used an old canal at the Love canalin Niagra Falls to dump the chemical wastes for about 20 yrs (1930-1950). . When the site was full , it was given

to the city of Niagra falls.

A new school & a housing complex were built on it. After 20 yrs the dumped chemicals began to leaking and the area was contaminated.

The population in the area were exposed to chemicals and led to birth defects and miscarriagerates as well as liver cancer.

Region wasofficially declared as a disaster area

Pesticides Chemicals to kill unwanted insects, fuungus, rodents, etc Control certain diseases and increase foood production Pose health risk to humans and environmental damage

DDT

used against pests, flies & mosquitoes

in India used for the eradication of mMalatia

Resulted in the pollution of crop lands, pests have been resistant to it

Enters into food chain, accumulates in the fatty tissues

ENVIRONMENTAL DISASTERS

CFC Uses: Refrigerant, in air conditionerssolvents in

electronic industry, propellants in aerosols Unraective and stay in the atmosphere for long tome

In the upper atm Reacts with O3 in presence of UV leads to O3 depletion

Minamata disease – Hg poisoning Chisco chemical company had been dumping about 27 tons

of Hg into Minamata bayfor more than 30yrs. (1932-68)

In 1950’s more than 50 people were died & a number of people were affected in Minamata, Japanby eating fish contaminated with Hg

Methylmercuric chloride Caused birth defects and affected neutral tissues mainly brain

Itai-Itai disease- JAPAN: Cd poisoning Cd pollution in Jinzu river :1912 victim,s mostly women suffered with pain in the entire

body Suffered with broken bones when trying to move

Methaemoglobinaemie Excessive use of Nitrogen fertilizers Nitrate ….> nitrite in digestive canalby bacteria

under high pH Haemoglobin ….> methamoglobin lacks O2

carrying capacity Severe for infants under six months; infants

appear blue

Cost to Industry

Industries in the US spend over $100 billion/year on waste treatment, control, and disposal.

1996 Dupont spent $ 1 billion for environmental compliance (research budget $ 1 billion; chemical sales of $18 billion)

Chemists Must Place a Major Focus on the Environmental Consequences of Chemical

Products and the Processes by which these Products are Made.

We must consider our chemical ecological footprint.

“Most of the environmental problems of past centuries and decades, such as the biological contamination of drinking water, were solved only when the methods of science in general—and chemistry in particular—were applied to them. The phenomenal rise in human life expectancy and in the material quality of life that has come about in recent decades is due in no small measure to chemicals and chemistry.”

— Colin Baird, Environmental Chemistry.

LAWS AND SIGNED INTERNATIONAL TREATIES TO REDUCE POLLUTION LEVELS,

• Montreal Protocol to Protect the Ozone Layer: Helsinki

• Stockholm Convention To Persistent Organic Pollutants: May 2004

• Rio Declaration on Environment and Development

• Environmental protection Agency:USA

GREEN CHEMISTRY GREEN CHEMISTRY

PREVENTING POLLUTION SUSTAINING THE EARTH

Focuses on a process (industry or laboratory) that reduces the use and generation of hazardous substances or by products

GREEN CHEMISTRY

GREEN CHEMISTRY

Pollution Prevention Act 1990 Dealt with the prevention of formation of pollutants GC Began in 1991 at EPA, Paul T. Anastas 1996 Presidential Green Chemistry Challenge Awards 1997 Green Chemistry and Engineering Conference 1999 Journal “Green Chemistry” Chemical & Engineering News 2001 Journal of Chemical Education 2005: Nobel prize for GC – Yves Chauvin, Robert Grubbs,

Richard Schroch

This Act led the industries to….. Devise technologies and processes that

avoided the formation and/or production of hazardous substances

Device greener reaction conditions

This was achieved by…. Replacing organic solvents by water / solid

state reactions Using catalyst Less toxic and biodegradable products

Twelve Principles of Green Chemistry1. Better to prevent waste than to treat or clean up after formed

2. Synthetic methods should be designed to maximize the incorporation of all materials into the final product

3. Synthetic methodologies should be designed to use and generate substances that possess little or no toxicity to human health and the environment

4. Products should be designed to preserve efficacy of function while reducing toxicity

5. Avoid the use of auxiliary substances (solvents, separation agents, etc) wherever possible

6. Energy requirements should be minimized. Synthetic methods should be conducted at ambient temperature & pressure

7. 7. Raw material feedstock should be renewable rather than depleting wherever technically and economically practicable

8. Should avoid unnecessary derivatization (blocking groups, protection/ deprotection, etc.) wherever possible.

9. Use catalytic reagents than stochiometric reagents.

10. Products should be designed in such away that at the end of their function they do not persist in the environment and break down to innocuous degradation products.

11. Analytical methodologies need further development to allow real-time, inprocess monitoring and control of hazardous substances prior to the formation.

12. Substances used in the chemical process should be chosen so as to minimize the potential for chemical accidents including releases, explosions, and fires.

Design synthetic pathway that at least reduce the formation of waste

waste : starting material or reagent, also pay for it.

waste: separate, treat, and dispose

Cost of disposal > cost of materials

Environmental pollution…> cleaned up

1. Better to prevent waste than to treat or clean up after formed

Maximize the incorporation of all materials into the final product – Atom economy

• % yield = Actual yield x 100 theoretical yield

• 100% yield: not a green reaction

Barry Trost (Stanford University)

Consider the amount of starting material incorporated into final product

How many atoms incorporated into product

Objective:

Waste / by-product is minimum

Develop a ‘greener’ reaction

% atom utilization = MW of desired product x100

MW of product + Waste

Atom Economy

• Quantified by Roger Sheldon

• % atom economy =

Atom Economy

FW of atom utilized x100

FW of all reactants used

GREEN CHEMISTRY MEANS…

• Saving companies money by using less energy and fewer/safer chemicals, thus reducing the costs of pollution control and waste disposal.

Achievements of Green Chemistry

New syntheses of Ibuprofen and Zoloft. Integrated circuit production. Removing Arsenic and Chromate from pressure

treated wood. Many new pesticides. New oxidants for bleaching paper and disinfecting

water. Getting the lead out of automobile paints. Recyclable carpeting. Replacing VOCs and chlorinated solvents. Biodegradable polymers from renewable resources.

Presidential Green Chemistry Challenge Award Winners For more informational on Presidential Green Chemistry Challenge Award Winners: http://www.epa.gov/greenchemistry/presgcc.html

LEAD POLLUTION HAS BEEN DECREASED BY…

• Replacing lead in paint with safe alternatives, and

• Replacing tetraethyl lead with less toxic additives (e.g., “lead-free” gasoline).

CHEMICAL FOAMS TO FIGHT FIRES

• Millions of tons of chemical fire-fighting foams used worldwide have discharged toxic substances into the environment, contaminating water supplies and depleting the ozone layer.

PUTTING OUT FIRES THE GREEN WAY

• 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 ground water.

A SAFER METHOD OF DRY CLEANING

• 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.

GREEN CHEMISTRY DEFINITION

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 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 Environmentally Benign Solvent systems

* Green Chemistry Theory & Practice, P T Anastas & J C Warner, Oxford University Press 1998

Catalysis

Process

Intensification

Separation

Processes

Energy

Efficiency

Solvent

Replacement

Safer Reactions

& Reagents

Use of

Renewable

Feedstocks

Waste

Minimisation

Some Aspects of Green Chemistry

Green

Chemistry

IN SUMMARY,GREEN CHEMISTRY IS…

• Scientifically sound,• Cost effective, and• Leads toward a sustainable

civilization.

Goals of Green chemistry

Design synthetic methodologies that reduce or eliminate the use and or generation o f toxic products

All possible routes may be examined

Most appropriate route (without hazardous starting materials and or products) should be used

No chemical accidents

Eg: synthesis of Adipic acid

Used for making nylon, PU, lubricants, plasticizers.

Ibuprofen

iso-butyl-propanoic-phenolic acid nonsteroidal anti-inflammatory drug (NSAID) Analgesic pain relief, fever reduction, and for reducing swelling Commercial synthesis developed by

Boot Chemical Company (1960s)

six step synthesis

Use large number of reagents

AE = 40%

Boots synthesis

BHC synthesis – greener synthesis

three steps

AE = 77%

• Safer dry cleaning Initially gasoline and kerosene were used Chlorinated solvents are now used, such as ‘PERC’ Hazardous waste contain solvent, powdered filter material,

carbon, non-volatile residues, lint, dyes, grease, soils, and water.

Supercritical/liquid carbon dioxide (CO2)

Designing a green synthesis

Starting materials

# Non hazardous

# Renewable

# No accident Reagent Easily available Efficient No effect on environment

Green reagents: dimethyl carbonate, polymer supported reagents like peracids, PNBS, polymer supported chromic acid (Amberlyst A-20)

Catalyst

# Avoid heavy metals like Ni, Pb, etc.

# Biocatalyst : enzymes,

# polymer supported catalyst

eg: PS- AlCl3, Polymer supported PTC

Solvent

# non toxic

# green solvents

Supercritical CO2, IL, water, solid state

Green Chemistry Is About...

Waste

Materials

Hazard

Environmental Impact

COST

Risk

Energy