General Presentation for our Chinese Visitors at UNIL (Switzerland)

1. The concept of green chemistry
22th April 2010
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Pierre-Philippe Chappuis, Dr. MSc
Contents
Introduction
What is really green chemistry ?
Sustainability metrics
Green chemistry definition
Twelve principles of green chemistry
Green chemistry metrics
Major Challenges to Sustainability
Conclusion
Bibliography
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2. Introduction (1)
Chemistry is undeniably a very prominent part of our
daily lives.
Chemical developments also bring new environmental
problems and harmful unexpected side effects, which
result in the need for “greener” chemical products.
A famous example is the pesticide DDT.
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Introduction (2)
Problems caused by chemical industries
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3. Introduction (3)
Sustainable development and business
A way of expressing SD in a business context is
in terms of the triple bottom line
- economic
- society
- environment
SD
"..development that meets the needs of the present without
compromising the ability of future generations to meet their own
needs"
World Commission on the Environment and Development
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Pierre-Philippe Chappuis, Dr. MSc
Introduction (4)
•
Sustainability
– Ecosystems
– Human Heath
•
Green Engineering
– Lifecycle
– Systems
– Metrics
– Thermodynamics
•
Green Chemistry
– Reactions, catalysts
– Solvents
– Thermodynamics
– Toxicology
– Metrics
Sustainability
Green Engineering
Green Chemistry
« Life cycle assessment and green chemistry : the yin and yang of industrial ecology »
P.T. Anastas, Green Chemistry, 2000, 2, 289-295
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4. What is really green chemistry ? (1)
Green chemistry, also called benign chemistry or
clean chemistry, is at the heart of Industrial Ecology
Adapted from P.T. Anastas & J.J. Breen, J. Cleaner Production, 1997
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What is really green chemistry ? (2)
Green Chemistry is the design of chemical products
and processes that reduce or eliminate the use and/or
generation of hazardous substances. It can be considered as a
set of reductions
Materials
Nonrenewables
Cost
Reducing
Risk &
Hazard
Energy
Waste
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5. Sustainability metrics (1)
Green metrics – What can be measured
Mass utilization
Material intensity (Mass in product/Mass in raw materials)
Atom economy
Potential environmental impact
Energy utilization
Energy intensity (per amount of product)
Materials consumed to produce required energy
Sustainability metrics
Eco-efficiency (Economic indicator/Environmental
indicator)
Ecological footprint
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Pierre-Philippe Chappuis, Dr. MSc
Sustainability metrics (2)
Materials
Pollutant Dispersion
Mass of raw material Mass of Product
Output
Total mass of pollutants released
Output
Water Consumption
Toxics Dispersion
Volume of fresh water used
Output
Total mass of recognized toxics released
Output
Energy
Land Use
Net energy used
Output
Land covered, paved, or in buildings
Output
Output = Mass of Product, Sales Revenue or Value-added
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6. Green chemistry definition (1)
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Green chemistry definition (2)
1. Prevention
2. Atom Economy
3. Less Hazardous Chemical Syntheses
4. Designing Safer Chemicals
5. Safer Solvents and Auxiliaries
6. Design for Energy Efficiency
7. Use of Renewable Feedstocks
8. Reduce Derivatives
9. Catalysis
10. Design for Degradation
11. Real-time Analysis for Pollution Prevention
12. Inherently Safer Chemistry for Accident Prevention
Anastas, P.T.; Warner, J. C. Green Chemistry: Theory & Practice, Oxford University Press:
New York, 1998.
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7. Green chemistry definition (3)
Prevent wastes
Renewable materials
Omit derivatization steps
Degradable chemical products
Use safe synthetic methods
Catalytic reagents
Temperature, pressure ambient
In-process monitoring
Very few auxiliary substances
E-factor, maximize feed in product
Low toxicity of chemical products
Yes, it is safe
S.L.Y. Tang, R.L. Smith and M. Poliakoff Green Chem, 7, 761-762, 2005
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Principle 1 : waste prevention (1)
It is better to prevent waste than to treat or clean up
waste after it is formed
Chemical
Process
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8. Principle 1 : waste prevention (2)
Redesign the Ibuprofen Process
Patent 1960
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Patent 1991
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Principle 1 : waste prevention (3)
Influence of product design on materials flows
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9. Principle 2 : atom economy (1)
Synthetic methods should be designed to
maximize the incorporation of all materials
used into the final product.
J. Andraos, Org. Process Res. Dev., 2006, 10(2), 212-240
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Principle 2 : atom economy (2)
Traditional synthesis of ibuprofen
(analgesic, anti-inflammatory)
6 stoichiometric steps
< 40% atom utilization
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10. Principle 2 : atom economy (3)
Catalytic synthesis of ibuprofen
3 catalytic steps
80% atom utilization (99% with recovered acetic acid)
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Principle 3 : less hazardous chemical
syntheses (1)
Wherever practicable, synthetic methodologies should
be designed to use and generate substances that
possess little or no toxicity to human health and the
environment.
Ecological-chemical footprint
RISK = ƒ (Hazard, Exposure)
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11. Principle 3 : less hazardous chemical
syntheses (2)
Polycarbonate Synthesis : Phosgene Process
Disadvantages
phosgene is toxic, corrosive
requires large amount of CH2Cl2
polycarbonate contaminated with Cl impurities
Polycarbonate Synthesis : Solid-State Process
Advantages
diphenylcarbonate synthesized without phosgene
eliminates use of CH2Cl2
higher-quality polycarbonates
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Principle 4 : designing safer chemicals (1)
Chemical products should be designed to preserve
efficacity of function while reducing toxicity.
Ecological-chemical footprint
RISK = ƒ (Hazard, Exposure)
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12. Principle 4 : designing safer chemicals (2)
Cationic electrodeposition coatings containing yttrium
provides corrosion resistance to automobiles
Replaces lead in electrocoat primers
Less toxic than lead and twice as effective on a
weight basis
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Principle 5 : safer solvents and
auxiliaries (1)
The use of auxiliary substances (e.g. solvents,
separation agents, etc.)
should be made unnecessary wherever
possible and, innocuous when used.
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13. Principle 5 : safer solvents and
auxiliaries (2)
Benign solvents
Carbon-carbon bond formation in water
Diels-Alder, Barbier-Grignard, pericyclic
Reactions in Supercritical Fluids
Formation of cyclic ethers
Hydrogenation
CO2 for Dry Cleaning
CO2 (l) Good solvent for small, nonpolar molecules:
Hydrocarbons < 20 carbon atoms & some aldehydes, esters,
and ketones
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Principle 5 : safer solvents and
auxiliaries (3)
Supercritical carbon dioxide
Physical Properties of CO2
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14. Principle 6 : design for energy
efficiency (1)
Energy requirements should be recognized
for their environmental and economic
impacts and should be minimized.
Synthetic methods should be conducted at
ambient temperature and pressure.
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Principle 6 : design for energy
efficiency (2)
Process Intensification
Methods
Equipment
Reaction
e.g. spinning
disc reactors
microreactors
Non-reaction
Multifunctional
Reactors
e.g. compact
heat exchanges
e.g. reactive distillation
Membrane reactors
Hybrid
separators
Alternative
Energy
sources
e.g. microwaves
Other
methods
e.g. membrane
adsorption
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15. Principle 6 : design for energy
efficiency (3)
Heating
Cooling
Stirring
Distillation
Compression
Pumping
Separation
GLOBAL
WARMING
Energy Requirement
(electricity)
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Burn fossil
fuel
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CO2 to
atmosphere
Pierre-Philippe Chappuis, Dr. MSc
Principle 7 : use of renewable
feedstocks (1)
A raw material of feedstock should be renewable
rather than depleting wherever technically and
economically practicable.
CO
2
Chemical
Industry
Biorefinery
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Consumer
Biomass
carbohydrates
Pierre-Philippe Chappuis, Dr. MSc

16. Principle 7 : use of renewable
feedstocks (2)
CO2 feedstock in polycarbonate synthesis
Conversion of waste biomass to levulinic acid
(paper mill sludge, municipal solid waste, unrecyclable
waste paper, agricultural residues)
Lactic acid as platform molecules
(corn starch -> undefined dextrose ->fermentation->
lactic acid -> monomer production -> lactide ->
polymer production -> Polylactic acid (PLA) ->
polymer modification -> fiber, film, bottle etc.)
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Principle 7 : use of renewable
feedstocks (3)
Biomass as an alternative feedstock for the chemical industry
Petroleum
Renewable
Non-renewable
Biomass
Platform molecules
Chemical
Products
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Plastics
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17. Principle 8 : reduce derivatives (1)
Unnecessary derivatization
(blocking group, protection/deprotection,
temporary modification of
physical/chemical processes)
should be avoided whenever possible.
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Principle 8 : reduce derivatives (2)
Example : synthesis of vitamin B2 (riboflavin)
Chemical process
Biotechnological process
8 steps chemical process
single step fermentation
process
use of renewable resources
66% less waste water
generated
Involving dangerous reagents
Dangerous waste generated
that needs to be incinerated
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no dangerous waste at all
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18. Principle 9 : catalysis (1)
Catalytic reagents (as selective as possible) are superior to
stoichiometric reagents.
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Principle 9 : catalysis (2)
Leading green chemical technology
Homogeneous catalysis
(eg PTC-Membranes)
Biocatalysis
(eg immobilized enzymes)
Heterogeneous
(eg zeolites / mesoporous solids)
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19. Principle 10 : design for degradation (1)
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.
Ecological-chemical footprint
RISK = ƒ (Hazard, Exposure)
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Principle 10 : design for degradation (2)
Routes of exenobiotic
organic chemical
introduction into
Agricultural systems
J.A. Pedersen and al., J. Agric. Food Chem. 2003, 51, 1360-1372
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20. Principle : 11 real-time analysis for
pollution prevention (1)
Analytical methodologies need to be further
developed to allow for real-time,
in-process monitoring and control prior to
the formation of hazardous substances.
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Principle 11 : real-time analysis for
pollution prevention (2)
An example of new analytical tool
for real-time industrial process
monitoring and for preventing the
formation of toxic materials
Electrochemical biosensors : intimate coupling of specific biorecognition
events
J.Wang, Acc. Chem. Res., 2002, 35(9), 811-816
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21. Principle 12 : inherently safer chemistry
for accident prevention
Substances and the form of a substance used in a
chemical process should be chosen so as to minimize
the potential for chemical accidents, including releases,
explosions, and fires.
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Green chemistry metrics (1)
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22. Green chemistry metrics (2)
E-Factor = Total Waste (kg) / Product (kg)
System boundaries ? Process only ? Include water ?
Can be sub-divided into organic waste, aqueous waste
Useful simple estimate of waste and resource efficiency (the smaller the better)
Roger A. Sheldon, Green Chem., 2007, 9, 1273, R. A. Sheldon, « Atom utilisation, E
factors and the catalytic solution » C. R. Acad. Sci. Paris, Série IIc (2000) 541
Sector
Product [t]
E-factor
Oil refining
106-108
<0-1
Bulk chemicals
104-106
1-5
Fine chemicals
102-104
5-50+
Pharmaceuticals
10-103
25-100+
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Green chemistry metrics (3)
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23. Green chemistry metrics (4)
Metric Name
Measures efficiency of
Formula
Analytical Atom
Economy AAE
Transformation of reactant
atoms into a desired product
necessary to prepare the
analyte for analysis.
Analytical Mass
Efficiency AME
Chemical and solvent use
involved in a chemical
reaction.
Method Mass
Efficiency MME
Comprehensive material use
necessary for entire analysis
method.
Energy per
Analytical Unit
EPAU
Energy use for entire analysis
method relative to the mass of
analyte in sample.
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AAE =
AME =
MME =
EPAU =
FW of Analyte
x 100
FW of Reagents
Mass of Analyte(g)
x 100
FW of Reagents, Solvents(g)
Mass of Analyte (g)
x 100
FW of Reagents, Solvents,
Cleaning, Prep (g)
Total method energy (kJ)
x 100
Mass of analyte (g)
Pierre-Philippe Chappuis, Dr. MSc
Green chemistry metrics (5)
for some Common Organic Reactions
Reaction
Type
Yield
Atom Economy
Environmental Impact
Factor assuming
100% yield
Nitration
96%
0.93
0.21
Amidation
92%
0.69
4.53
Reduction
100%
0.94
0.06
Methylation
91%
0.63
0.55
Bromination
31%
0.71
0.41
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24. Green chemistry metrics (6)
Ecological metrics
Parameters considered
•Raw Materials
Ecological footprint
Ecological advantage
Draft
Relative environmental
impact
Energy Consumption
1.00
•Energy consumption
Land Use
•Land Use
•Emissions
Emissions
0.50
High
0.00
•Toxicity
•Risk potential
Product 2
« »
Raw Materials
Product 3
Toxicity Potential
Product 1
Risk Potential
Low
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The major challenges to sustainability (1)
Green chemistry
Not a solution to all environmental problems.
The most fundamental approach to preventing
pollution.
Recognizes the importance of incremental
improvements.
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25. The major challenges to sustainability (2)
Population
Energy
Global Change
Resource Depletion
Food Supply
Toxics in the Environment
Conclusion
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Population
Empirical data shows that increased quality of life
correlates with sustainable population control.
Increased quality of life, however, has historically
resulted in increased damage to the biosphere and the
earth’s ability to sustain life.
The challenge: How to increase quality of life while
minimizing detrimental effects to human health, the
environment and the biosphere.
The solution: Green chemistry provides a mechanism
to addressing this challenge in very real terms.
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26. Energy (1)
The vast majority of the energy generated
in the world today is from non-renewable
sources that damage the environment.
Carbon dioxide
Depletion
Effects of mining, drilling, etc.
Toxics
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Energy (2)
Green Chemistry will be essential in
developing the alternatives for energy
generation (photovoltaics, hydrogen, fuel
cells, biobased fuels, etc.) as well as
continuing the path toward energy
efficiency with catalysis and product design
at the forefront.
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27. Global change
Concerns for climate change, oceanic temperature,
stratospheric chemistry and global distillation can
be addressed through the development and
implementation of green chemistry technologies.
For instance :
CO2 blowing agent for manufacture of polystyrene foam sheet packaging
eliminates 1.6 million kg/year of chlorofluorocarbon blowing
agents
carbon dioxide obtained from existing by-product commercial and
natural sources, no net increase in global CO2
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Resource depletion
Due to the over utilization of non-renewable resources,natural
resources are being depleted at an unsustainable rate. Fossil
fuels are a central issue. Renewable resources can be made
increasingly viable technologically and economically through
Green chemistry.
Biomass
Nanoscience & technology
Solar
Carbon dioxide
Chitin
Waste utilization
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28. Food supply
While current food levels are sufficient, distribution is inadequate.
Agricultural methods are unsustainable. Future food production
intensity is needed.Green chemistry can address many food
supply issues.
Green chemistry is trying to develop :
Pesticides which only affect target organisms and degrade to innocuous
by-products.
Fertilizers and fertilizer adjuvants that are designed to minimize usage
while maximizing effectiveness.
Methods of using agricultural wastes for beneficial and profitable use
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Toxics in the Environment
Substances that are toxic to humans, the biosphere
and all that sustains it, are currently still being
released at a cost of life, health and sustainability.
One of Green chemistry’s greatest strengths is the
ability to design for reduced hazard.
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29. Perspectives
Objectives for Green Chemists around the world
Include Green Chemistry principles in the Environment and Education
Initiative.
Train a new generation of scientists, engineers, and technical works.
Account for chemical toxicity and impacts in governmental procurement
decisions.
Expand world’s pollution prevention program.
Strengthen consumer protection enforcement.
Empower consumers to make informed choices.
Forge strategic partnerships and disseminate information on toxic chemicals
and inadequate processes.
Apply the TCCR principles : Transparency, Clarity, Consistent and
Reasonable.
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Conclusion (1)
Green chemistry
A philosophy, not exactly a scientific discipline.
Not a solution to all environmental problems.
Cost effective.
The most fundamental approach to preventing pollution.
A catalyst for sustainable development of the world !
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30. Conclusion (2)
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Bibliography (1)
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31. Bibliography (2)
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Bibliography (3)
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32. Bibliography (4)
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Green Chemistry Around the World
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33. Listen to Nature, Learn from Nature
“Being ‘less bad’
is no good.”
The world will not evolve past its current state of crisis by using the same
thinking that created the situation.
-Albert Einstein
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Thank for your attention !
Questions ?
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