green chemistry
TRANSCRIPT
Green Chemistry and its Role for Sustainability
As
A branched topic of the UNESCO conference on ESD
Bonn, Germany, 2009
Presenter: Dr. Zeinab Shaaban Abu-ElnagaFaculty of Science
Mansoura University
Egypt2009
Learning 0bjectives To conceptualize the sustainability and ESD
To understand how to apply this concept in our research
fields of interest aiming to safe our plant
To think prospectively about how to change our
education subjects to be sustainable learning tools by
Investigating examples of green chemistry applications
relevant to students
To understand the important role of the green chemistry
and how to deal with it in our practical life
The topic is very vast but I have tried to cover it in one
lecture and I will give the links for more details of
each sub-topic 2009 [email protected]
Performance Objectives:
To understand the importance of Green chemistry for
sustainability
To design and interpret greener route to the traditional
chemical reactions
To learn how to teach green chemistry as a lab course
2009 [email protected]
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
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
Sustainabledevelopmentthe goal
Green chemistry, lies at the heart of the industrial ecology2009
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
Principles of Green ChemistryPrevent 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 [email protected]
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
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
2009 [email protected]
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
2009 [email protected]
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
ethylbenzenestyrene
2009 [email protected]
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
2009 [email protected]
conclusionGreen Chemistry:Green Chemistry:Preventing PollutionSustaining 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 [email protected]
References 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_TRANSITIO
NMAIN&node_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=fr
ontcover&source=bl&ots=ZdGD63CxOJ&sig=vM94PxekSEhIX3a9yFOPpDAOXGo&hl
=en&ei=mD9RSqSoDqDMjAfJg4mfBQ&sa=X&oi=book_result&ct=result&resnum=8
http://books.google.com/books?id=ZMjkTMwO3NkC&dq=green+chemistry&printsec=fr
ontcover&source=bl&ots=ZdGD63CxOJ&sig=vM94PxekSEhIX3a9yFOPpDAOXGo&hl
=en&ei=mD9RSqSoDqDMjAfJg4mfBQ&sa=X&oi=book_result&ct=result&resnum=8
2009 [email protected]