The document discusses green chemistry and sustainability. It defines a sustainable civilization as one where technologies do not harm the environment or health, renewable resources are used rather than finite ones, and waste is recycled or biodegradable. Green chemistry works toward sustainability by designing chemicals and processes that minimize pollution and waste. It means preventing pollution from the start through efficient, cost-effective designs. Examples show reducing lead pollution and safer dry cleaning. In summary, green chemistry is scientifically sound, cost-effective, and leads to a more sustainable future.
3. WE SHOULD 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.
4. 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.
5. 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.
6. 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).
7. IN A SUSTAINABLE
CIVILIZATION…
• Manufacturing processes are either
designed so as not to produce waste
products,
– OR –
• Waste products are recycled or
biodegradable.
9. BENEFITS OF
CHEMICAL INDUSTRY:
• Antibiotics and other medicines
• Fertilizers, pesticides
• Plastics
• Nylon, rayon, polyester, and
other synthetic materials
• Gasoline and other fuels
• Water purification
• Organic Semiconductors
10. THE POLLUTION
PREVENTION ACT OF 1990
• This was the U.S. environmental
law stating that the first choice
for preventing pollution is to
design industrial processes that
do not lead to waste production.
• This is the approach of green
chemistry.
11. GREEN CHEMISTRY
WORKS TOWARD
SUSTAINABILITY BY:
• Making chemical products that do not
harm either our health or the
environment,
• Using industrial processes that reduce
or eliminate hazardous chemicals, and
12. GREEN CHEMISTRY
WORKS TOWARD
SUSTAINABILITY BY:
• Designing more efficient processes that
minimize the production of waste
materials.
13. GREEN CHEMISTRY
MEANS…
• Preventing pollution before it
happens rather than cleaning up the
mess later.
14. GREEN CHEMISTRY
MEANS…
• Saving companies money by
using less energy and fewer/safer
chemicals, thus reducing the
costs of pollution control and
waste disposal.
15. EXAMPLES OF
GREEN CHEMISTRY
• Reducing lead pollution
• Putting out fires the green
way
• Safer dry cleaning
16. IN SUMMARY,
GREEN CHEMISTRY IS…
• Scientifically sound,
• Cost effective, and
• Leads toward a sustainable
civilization.
17. Is Green Chemistry only applied modern chemistry?
An academic chemist may contribute by making focused
fundamental research to:
- identify novel processes efficient from both the chemical and
environmental point of views.
- Study how a novel medium influences the reactivity of organic
molecules and discover new synthetic tools by exploiting the
properties of novel reaction media.
- Define easily scalable and automatizable procedure.
- Eliminate the use of unacceptable organic solvents.
The use of unconventional media does NOT turn a process GREEN…
18. Is Green Chemistry only applied modern chemistry?
An academic chemist may contribute by making focused
fundamental research to:
- identify novel processes efficient from both the chemical and
environmental point of views.
- Study how a novel medium influences the reactivity of organic
molecules and discover new synthetic tools by exploiting the
properties of novel reaction media.
- Define easily scalable and automatizable procedure.
- Eliminate the use of unacceptable organic solvents.
The use of unconventional media does NOT turn a process GREEN…
19. SOME UNCONVENTIONAL REACTION MEDIA
Water
Ionic Liquids
Supercritical Fluids
Solvent-free… best choice is NO SOLVENT
20. Why do we need a solvent/reaction medium?
• To dissolve reactants
• To stabilize a transition state
• To promote a reaction path
• To control the thermal exchange during the
reactive event
• To purify the product
• To analyze the reaction mixture and run purity
tests
21. Main properties of solvents
• Solubility “power”
• Polarity
• Density and viscosity
• Boiling point
• Toxicity, explosivity
• Influence on Ozone depletion
• Greenhouse effect
22. How Green is a solvent?
First of all a solvent should be non-toxic for human
beings, animals and plants.
In addition it should be considered:
• Energy (evaporation, pressurization, etc.)
• Recovery and Recycle of the solvent
• Toxicity of the related by-product
• Influence of the solvent on the final product
Does the solvent comes from
renewable resources?
23.
24. WATER AS REACTION MEDIUM
WHY?
Water is a high-boiling liquid.
Organic reaction mixtures are generally heterogenous in water.
The evaporation of water to recover the species dissolved in, is
costly and tedious.
Is it worth to perform organic reactions in water?
25. ADVANTAGES in the use of WATER AS REACTION MEDIUM
• Water actively participates to the process.
• In Water it is often unnecessary the protection-deprotection
of functional groups (-OH, -COOH).
• IN WATER it is possible to influence the reactivity and
the selectivity of a process by controlling/modifying
the pH.
• It allows to isolate solid products by simple filtration.
• WATER IS NOT TOXIC.
