brief introduction and some examples to green chemistry

1. GREEN CHEMISTRY
PRESENTED BY:
FAZIL T S
15 ICM 20
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2. Highlights of presentation
1
• introduction
2
• Green Chemistry and Sustainability
3
• 12 Principles of Green Chemistry
4
• Conclusions
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3. GREEN CHEMISTRY
• Green chemistry, also called sustainable chemistry,
is an area of chemistry and chemical engineering
focused on the designing of products and processes
that minimize the use and generation of hazardous
substances.
• Green chemistry focuses on technological
approaches to preventing pollution and reducing
consumption of non-renewable resources.
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4. Green Chemistry and
Sustainability
 Sustainability: Meeting the needs of the present
generation without compromising the needs of
future generations.
• Making chemicals safe for our health & environment,
• Using industrial processes that reduce or eliminate
hazardous chemicals, &
• Designing more efficient processes that minimize waste
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5. 12 Principles of Green Chemistry
• In 1998, Paul Anastas (who then
directed the Green Chemistry Program
at the US EPA) and John C. Warner
published a set of principles to guide the
practice of green chemistry
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6. 1. Prevention
• Waste prevention is much better than
waste clean-up
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7. 2. Atom Economy
• Synthetic methods should be designed to maximize
the incorporation of material used in the process in to
the final product.
Atom Economy =
mol. Wt. of the desire product
mol. Wt. of the all reactants
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• Reactions with a high atom economy
tend to be more environmentally
friendly as they tend to produce less
waste.
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8. 3. Less Hazardous Chemical
Synthesis
• The use or generation of substances
that pose hazards to humans and the
environment should be avoided.
 Example: Firefighting foam that
contains hydrocarbon surfactants,
water, solvent, complex carbohydrates
and a corrosion inhibitor .
 Eliminated the use of fluorinated
surfactants.
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9. 4. Designing Safer Chemicals
• Chemical products should be as effective
as possible for their designated purpose
but with minimum toxicity.
 Example: In the manufacturing process of
Polystyrene, CFC’s which contribute to
the ozone depletion replaced by CO₂
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10. 5. Safer Solvents and Auxiliaries
• The use of auxiliary substances (e.g. solvents,
separation agents, etc.) should be made
unnecessary wherever possible and innocuous
when used.
( the major problem with many solvents is their volatility
that may damage environment and human health )
 Example : To avoid this many
reactions are carried out in safer green
solvents like ionic liquids, Supercritical
CO₂ fluid etc. which are non-volatile.
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11. 6. Design for Energy Efficiency
• Energy requirements should be
recognized for their environmental
and economic impacts and should be
minimized.
 Example: if the final product is impure it has to
be purified by distillation or recrystallization
these steps requires energy which is
uneconomical.
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12. 7. Use of Renewable Feedstocks
• Feedstock or raw material should be
renewable rather than depleting
wherever technically and economically
practicable.
 Example: Ethene from bioethanol,
which is used to make poly(ethene) and
methane gas are considered as
renewable starting materials.
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13. 8. Reduce Derivatives
• Unnecessary derivatization (blocking
group, protection/deprotection)
should be avoided whenever possible.
• Adopt selective and better alternative
synthetic sequences.
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14. 9. Catalysis
• Catalytic reagents (as selective as possible)
are superior to stoichiometric reagents.
 Example: Activate H₂O₂ for chlorine-free
wood pulp bleaching.
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15. 10. Design for Degradation
• Chemical products should be designed so
that at the end of their function they do not
persist in the environment and break down
into innocuous degradation products.
 Example: Bio degradable polymers
 Polypropylene carbonate (PPC) is a
common example for Bio degradable
polymers
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16. 11. Real-time Analysis for Pollution
Prevention
• successful practice of green chemistry
requires real-time, in-process monitoring
techniques coupled with process control.
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17.  Example: when coal is burnt in industrial
boilers, SO₂ (a pollutant) is formed.
If the temperature of the boilers is too
high , a large amount of SO₂ generated
can be measured all the time.
Once it reaches an unacceptable level, an
alarming signal will be generated.
Then the temperature will be lowered
immediately
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18. 12. Inherently Safer Chemistry for
Accident Prevention
• Substances and the form of a substance
used in a chemical process should be chosen
to minimize potential for chemical
accidents, including releases, explosions,
and fires.
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19. Example: Vegetable Oil Dielectric
Insulating Liquid
Made from vegetable oils - biodegradable and
nontoxic.
Replaces mineral oil (with law flash point).
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20. Conclusions
 Green Chemistry is about..
Reducing
WASTE
MATERIALS
HAZRD
RISK
ENERGY
COST
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21. All over the world,
governments and
industries are
working with “green”
chemists to transform
the economy into a
sustainable enterprise
Green chemistry is a
tool in achieving
Sustainability.
Green chemistry
provides solutions to
climate change.
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22. REFERANCE
 http://www.epa.gov/greenchemistry/
 http://www.epa.gov/greenchemistry/pubs/educat.html
 http://www.epa.gov/greenchemistry/
 http://www.epa.gov/greenchemistry/pubs/principles.html
 http://en.wikipedia.org/wiki/Green_chemistry
 http://portal.acs.org/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_TRANSITIONMAIN&n
ode_id=830&use_sec=false&sec_url_var=region1&__uuid=76247a16-94d0-458e-9092-10de1c35f2c6
 http://books.google.com/books?id=ZMjkTMwO3NkC&dq=green+chemistry&printsec=frontcover
&source=bl&ots=ZdGD63CxOJ&sig=vM94PxekSEhIX3a9yFOPpDAOXGo&hl=en&ei=mD9RSqS
oDqDMjAfJg4mfBQ&sa=X&oi=book_result&ct=result&resnum=8
 http://books.google.com/books?id=ZMjkTMwO3NkC&dq=green+chemistry&printsec=frontcover
&source=bl&ots=ZdGD63CxOJ&sig=vM94PxekSEhIX3a9yFOPpDAOXGo&hl=en&ei=mD9RSqS
oDqDMjAfJg4mfBQ&sa=X&oi=book_result&ct=result&resnum=8
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