Green chemistry aims to reduce or eliminate the use and generation of hazardous substances. It promotes the design of chemical products and processes to be more sustainable and environmentally friendly. The principles of green chemistry include preventing waste, designing safer chemicals and synthesis, and utilizing renewable starting materials like catalysts. Educating students and researchers about green chemistry approaches can help transition industry practices towards more sustainable methods.
2. Sustainability
• Meeting the needs of the present generation without
compromising the needs of future generations
• Green chemistry: technologies of the invention, design
and application of chemical products and processes to
reduce or to eliminate the use and generation of
hazardous substances ,and where possible utilize
renewable raw materials
Primary pollution prevention not remediation
Use of chemistry for improved environmental performance
Is the goal
is the means
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3. As human beings --- we are part of the environment
The way in which we interact with our environment influences
the quality of our lives
Green
Chemistry
A tool
Industrial
ecology
Sustainable
development
the goal
Green chemistry, lies at the heart of the industrial ecology
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4. Green chemistry, is called also Benign chemistry or clean
chemistry for sustainability
• Refers to the field of chemistry dealing with
1- Synthesis (the path to making chemicals)
2- Processing (the actual making of chemicals)
3- Use of chemicals that reduce risks to humans and
impact on the environment
Green chemistry education: A key to sustain the
development of new educational materials
5. Green Chemistry Is About...
Cost
Waste
Materials
Hazard
Risk
Energy
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6. Principles of Green Chemistry
Prevent waste.
Design safer chemicals and products.
Design less hazardous chemical syntheses.
Use renewable feed stocks.
Use catalysts, not stoichiometric reagents: Catalysts are used in small amounts and
can carry out a single reaction many times. They are preferable to stoichiometric
reagents, which are used in excess and work only once.
Avoid chemical derivatives: Avoid using blocking or protecting groups or any
temporary modifications if possible. generate waste.
Maximize atom economy.
Use safer solvents and reaction conditions
Increase energy efficiency.
Design chemicals and products to degrade after use.
Analyze in real time to prevent pollution.
Minimize the potential for accidents.
Originally published by Paul Anastas and John Warner in Green Chemistry: Theory
and Practice (Oxford University Press: New York, 1998). 2009
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7. Now, how can we deal with green chemistry
at our practical life
Just we need to change our mind set
and applying the concept in
Classrooms
laboratory
manufacture
And finally the surrounding
environment
8. O3 or supercritical water oxidation
• If the chemical reaction of the type
• A + B P + W
• Find alternate A or B to avoid W
• Example 1:
• Disinfection of water by chlorination. Chlorine
oxidizes the pathogens there by killing them,
but at the same time forms harmful chlorinated
compounds.
• A remedy is to use another oxidant, such as
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9. Example 2 of green chemistry
• Production of allyl alcohol CH2=CHCH2OH
• Traditional route: Alkaline hydrolysis of allyl chloride, which
generates the product and hydrochloric acid as a by-product
• Greener route, to avoid chlorine: Two-step using propylene
(CH2=CHCH3), acetic acid (CH3COOH) and oxygen (O2)
• Added benefit: The acetic acid produced in the 2nd
reaction
can be recovered and used again for the 1st
reaction, leaving
no unwanted by-product.
CH2=CHCH2Cl + H2O CH2=CHCH2OH + HCl
problem product
CH2=CHCH2OCOCH3 + H2O CH2=CHCH2OH + CH3COOH
CH2=CHCH3 + CH3COOH + 1/2 O2 CH2=CHCH2OCOCH3 + H2O
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10. Example 3 of green chemistry
• Production of styrene (=benzene ring with CH=CH2 tail)
• Traditional route: Two-step method starting with benzene,
which is carcinogenic) and ethylene to form ethylbenzene,
followed by dehydrogenation to obtain styrene
• Greener route: To avoid benzene, start with xylene (cheapest
source of aromatics and environmentally safer than benzene).
• Another option, still under development, is to start with
toluene (benzene ring with CH3 tail).
+ H2C=CH2
catayst
CH2CH3
ethylbenzene
catayst
CH=CH2CH2-CH3
ethylbenzene
styrene
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11. Green chemistry education
Chemistry students need to be encouraged to
consider the principles of green chemistry when
designing processes and choosing reagents
Interactive Teaching Units (ITU) have been
developed specifically to introduce undergraduate
students to green chemistry
There are numerous scholarships and grants
available for researchers and young scholars who
are furthering the goals of green chemistry
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12. conclusion
Green Chemistry:Green Chemistry:
Preventing Pollution
Sustaining the Earth
Green chemistry has come a long way since its birth in 1991,
growing from a small grassroots idea into a new approach to
scientifically-based environmental protection
All over the world, governments and industries are working
with “green” chemists to transform the economy into a
sustainable enterprise
Who knows? Green chemistry may be the next social
movement that will set aside all the world’s differences and
allow for the creation of an environmentally commendable
civilization 2009
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