Green Chemistry
Hermenegildo Garcia
Department of Chemistry
D2Q-9
96 387 7807
(ext 73441 y 78572)
hgarcia@qim.upv.es
www.upv.es/herme
How to pass the course?
• Attendance to class is mandatory
•You can miss one class max.
• To perform exercises and homework
•Assignment
•Correct exercises
•Present in due time
•Public presentation (30 min)
•Written exam
• Volonteers
4
7
10
Assignment List
• History
• Examples of novel green chemistry processes
• Presidential Green Chemistry Challenge award
winners
• Propose practical demonstrations
• Renewable feedstocks
• EPA grants
• Search for reviews and literature reports
• Search for web pages and electronic addresses
• Assistance to prepare new class material
Actions aiming at Green Chemistry
Goverment
•Laws and regulations
•Control
•Funding and promotion
Industry
• Development of new processes
• Development of new products
• New renewables feedstocks
• Safe operation
Academia
• Courses and training
• Research in new processes
General public
• Information
• Good practices
• Support extra costs
The ACS/EPA Cooperative Agreement
• What is the EPA?
• What is ACS?
• EPA/ACS collaboration
Propose nominations to the Presidential Green
Chemistry Challenge Awards Program
Highlights the concerns with current products and
processes
Presents a green chemistry solution
Real-World Cases in Green Chemistry
ACS Activities
 Earth
Day Program
 Green chemistry in the curriculum
(books)
 Green chemistry summer school
 National Chemistry Week
 Interactive Teaching Units
Europe and Japan
• Royal Society of Chemistry
• Venice (7th Summer school in green
chemistry)
• Barcelona (Green Chemistry PhD course)
• European Commission (Cost Actions)
• York and other European Universities
• Japan is developing very strong initiatives
Can the Chemistry be Dirty?
Atmospheric pollution
• Green house effect and energy consumption
• Ozone layer depletion
• Photochemical smog
• Smoke (NOx and SOx)
Aqueous pollution
• Fertilizers, pesticides, insecticides
• Industrial waste waters
• Solvents
• Detergents and urban waste waters
Solid pollution
• Industrial soils
• Nuclear and radiactive wastes
• Chemical residues
Examples of Chemical
Products of the 20th Century
Thalidomide.
DDT.
CFCs.
Endocrine
disruptors.
Bioaccumulating substances.
Persistent/non-biodegradable
materials.
Why the chemistry is dirty?
• Provides energy
• Provides materials (plastics, paper, etc)
• Provides commodities (sprays, detergents,
paints, dyes)
• Provides fertilizers, insecticides, pesticides
• Provides drugs and pharmaceuticals
• Social demand
• Social complain
Growth of Legal Regulation
E PAC T
FFC A
C E R FA
C R AA
AM FA
AR PAA
AJA
AS B C AA
E S AA-AE C A
FFR AA
FE APR A
IR A
NWPAA
C ODR A/NM S PAA
FC R PA
M M PAA
120
110
100
80
70
60
B LB A
FWPC A
M PR S A
C ZM A
NC A
FE PC A
PWS A
M M PA
50
Laws
NAWC A
R C R AA
WLDI
APA
S WDA
C E R C LA
C ZM IA
C OWLDA
FWLC A
M PR S AA
C AAA
C WA
S MCRA
S WR C A
S DWAA
90
Number of
AQ
A
40
30
AQA
FOIA
20
WQA
NWP A
AR PA
S DWAA
S AR A
M PR S AA
HM TA
ES A
TAPA
FR R R PA
S OWA
DP A
FC M HS A
WR P A
AFC A
10
TA
FWC A
B PA
0
R HA
YA
1870
1880
1890
WA
NB R A
IA
AA
1900
1910
NPS
1920
MBCA
1930
AE PA
FHS A
NFM UA
FIFR A PAA
FAWR A
NLR A
WPA
1940
1950
AE A
NHPA
WLDA
FWC AA
FWA
1960
1970
WS R A
EA
R C FHS A
1980
PPA
PPVA
IE R E A
ANTPA
G LC PA
AB A
C ZAR A
WR DA
E DP
OPA
RECA
C AAA
GCRA
G LFWR A
HM TUS A
NE E A
1990
B LR A
E R DDAA
E AWA
NOPPA
PTS A
UM TR C A
E S AA
QG A
NC PA
TS C A
FLPM A
RCRA
NFM A
C ZM AA
NE PA
E QIA
C AA
E PA
EEA
OS HA
FAWR AA
NP AA
2000
What is Green Chemistry?
•Environmentally
friendly processes
•Sustainability
Benign
Disposal
Recycle/Re-use
Reduce Replace -
Chemical usage
Energy usage
Hazardous materials, processes
Inefficient processes
Non-sustainable components
Green Chemistry Technologies and Solutions
• What is Green Chemistry?
•Chemistry to provide commodities being environmentally friendly and sustainable
• How do we know what is Green?
• A dip into the Clean/Green technology Pool
with some examples.
How do we know what is Green?
Metrics in Green Chemistry
“When you can measure what you are speaking about, and
express it in numbers, you know something about it; but when
you cannot measure it, when you cannot express it in numbers,
your knowledge is of a meagre and unsatisfactory kind; it may be
the beginning of knowledge, but you have scarcely, in your
thoughts, advanced to the stage of science” William Thompson,
Lord Kelvin, (1891)
“If you don’t keep score then you are only practising”
Metrics in Green Chemistry
How do we know what progress we are making?
⇒ E - Factor
Amount of waste/kg product:
Product tonnage
E Factor
Bulk Chemicals
104-106
<1 - 5
Fine chemical Industry
102-104
5 - >50
Pharmaceutical Industry
10-103
25 - >100
R.A. Sheldon, Chem & Ind, 1997,12
Metrics in Green Chemistry
Preparation of 2-methoxypropane-1,3-diol from glycerol
OH
OH
HO
+
[92]
+
[278.5]
OH
OTr
TrO
2TrCl
+
MeI
+
2Et3N
OH
OTr
TrO
+
[101]
Et3N
[137.5]
OMe
OTr
TrO
+
[142]
OMe
TrO
OTr
+
2AcOH
[60]
2Et3N.HCl
Et3N.HI
[229]
OMe
OH
HO
[106]
+
2TrOAc
[302]
Assuming 100% yields, no reaction or work-up solvents and no reagent
excesses 1 kg glycerol produces 1.15 kg 2-methyl ether and 12.04 kg of waste!
Atom Economy
Atom economy =
MW of desired product
Σ MWs of all substances produced
•Diels-Alder Reaction
O
O
100% Atom economy
+
•Wittig Reaction
•O
+
+ _
Ph3P CH2
C H•2
+
Ph3 P=O
35% Atom economy
Catalysis
Safer reactions
and reagentsNew Chemistry
Renewable
Feedstocks
Alternative
Solvents
Chemical
recycling
Membrane
reactors
Innovative
Engineering
12 Principles of Green Chemistry
•
•
•
•
Prevent waste: Design chemical syntheses to prevent
waste, leaving no waste to treat or clean up.
Design safer chemicals and products: Design chemical
products to be fully effective, yet have little or no
toxicity.
Design less hazardous chemical syntheses: Design
syntheses to use and generate substances with little or no
toxicity to humans and the environment.
Use renewable feedstocks: Use raw materials and
feedstocks that are renewable rather than depleting.
Renewable feedstocks are often made from agricultural
products or are the wastes of other processes; depleting
feedstocks are made from fossil fuels (petroleum, natural
gas, or coal) or are mined.
12 Principles of Green Chemistry
•
•
•
•
Use catalysts, not stoichiometric reagents: Minimize waste
by using catalytic reactions. 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.
Derivatives use additional reagents and generate waste.
Maximize atom economy: Design syntheses so that the final
product contains the maximum proportion of the starting
materials. There should be few, if any, wasted atoms.
Use safer solvents and reaction conditions: Avoid using
solvents, separation agents, or other auxiliary chemicals. If
these chemicals are necessary, use innocuous chemicals.
12 Principles of Green Chemistry
•
•
•
•
Increase energy efficiency: Run chemical reactions at
ambient temperature and pressure whenever possible.
Design chemicals and products to degrade after use:
Design chemical products to break down to innocuous
substances after use so that they do not accumulate in
the environment.
Analyze in real time to prevent pollution: Include inprocess real-time monitoring and control during
syntheses to minimize or eliminate the formation of
byproducts.
Minimize the potential for accidents: Design
chemicals and their forms (solid, liquid, or gas) to
minimize the potential for chemical accidents including
explosions, fires, and releases to the environment.
Pharmaceutical Applications
Traditional synthesis of ibuprofen
O
O CHCO2C2H5
ClCH2CO2C2H5
NaOC2H5
(CH3CO)2O
AlCl3
CHO
H+
H2O
HC NOH
H2NOH
CN
CO2H
Ibuprofen
Pharmaceutical Applications
Alternative synthesis of ibuprofen
O
H2
catalyst
(CH3CO2)O
HF
CO2H
OH
CO, Pd
BHC Company
Ibuprofen
Redesign of the Sertraline
Process
Pd/C, H2
TiCl4/ MeNH2
(D)-mandelic acid
EtOH
toluene/hexanes
THF
Cl
"imine"
isolated
+ TiO2
+ MeNH4Cl
EtOAc
HCl
Cl
Cl
Cl
Cl
O
NMe
NMe
NMe
NMe
Cl
racemis mixture
cis and trans isomers
Cl
Sertraline Mandelate
isolated
Cl
Sertraline
isolated
final product
Cl
Cl
NMe
MeNH2
EtOH
NMe
+ H2O
PdC/CaCO3
H2/EtOH
Cl
Cl
"imine"
not isolated
NMe
Cl
(D)-mandelic
acid
EtOH
MeOH rex
NMe
EtOAc
HCl
Cl
Cl
Cl
racemic mixture
not isolated
Sertraline Mandelate
isolated
Cl
Cl
Sertraline
isolated
final product
Alternative Synthetic Pathways
Sodium
iminodisuccinate
 Biodegradable,
environmentally friendly
chelating agent
 Synthesized in a waste-free process
 Eliminates use of hydrogen cyanide
Bayer Corporation and Bayer AG
2001 Alternative Synthetic Pathways Award Winner
O
O
O
O
NaOH
NH3
O
NaO
ONa
NaO
ONa
N
O
H
O
New Chemistry: Synthesis of 4-ADPA
Monsanto’s new route: rubber antidegradant
130,000 M tonnes/annum
Starting Material: Aniline
NH2
Green Chemistry
Safer.
No Organo-halogens.
Waste Minimised -74% less
organic, 99% less water.
Reusable catalyst employed.
Reduced Cost.
Traditional Chemistry
Organo-halogens used.
Hazardous Solvent used.
High Waste levels.
N
H
NH2
Product: 4-ADPA
Catalysis
Zeolites as Alternatives to Classical Routes
• Alumino-silicates
• 3D crystalline structure
• Uniform pore size
• Green applications in
> Catalysis
> Water treatment
> Remediation
> Odour control
Zeolites: Chemical Composition
PRIMARY STRUCTURE
Organic or inorganic
Exchangeable
Acid Zeolites H+
Control:
• during synthesis
• after synthesis
Mx/n x+ [AlxSiyO
]
x+y)
2(
y/x between 1 and ∞
number of countercations
hydrophylicity
x-
zH O
2
Variable
Thermally reversible
Zeolites:Microporous Solids
• More than 30 natural zeolites
• More than 300 synthetic zeolites
Pore Diameter (Å)
30
Mesoporous
20
18 Ox
MCM-41
12 Ox
10
10 Ox
VPI-5
8 Ox
Erionita
small
ß, Y, ž
ZSM-5
medium
large
Pore size
extra large
SUPRAMOLECULAR CHEMISTRY
Molecular Sieves
Microscopic Reactor
Reaction Cavity
Molecular Pockets
SOME COMMON TOPOLOGIES
Faujasite
(zeolites X and Y):
tridirectional,
large pore (13 Å)
BEA
(zeolite Beta):
tridirectional,
large pore (12 Å)
Pentasil
(silicalite and ZSM-5):
bidirectional,
medium pore (5.4X5.62)Å
MCM-41:
unidirectional,
mesoporous (20 Å)
Zeolite Particles by SEM
ADVANTAGES OF ZEOLITES AS HOSTS
• WELL DEFINED SOLIDS
• SYNTHETIC MATERIALS
– REPRODUCIBILITY BETWEEN BATCHES
– CONTROL OF CHEMICAL COMPOSITION
– LARGE AMOUNTS g ⇒ Ton
• THERMAL AND CHEMICAL STABILITY
• LARGE VARIETY
– SIZE AND GEOMETRY OF MICROPORES
• OTHERS:
– ACTIVE SITES
– TRANSPARENT TO UV RADIATIONS
ACID ZEOLITES:
H+ AS CHARGE BALANCING CATION
• CASE OF ZEOLITE Y (POST-SYNTHETIC EXCHANGE)
+
NH4
NH4 Y
NaY
+
Na
>500
o
HY
NH 3
• CASE OF ZSM-5 (AS-SYNTHESIZED SAMPLES)
o
NPr4 ZSM-5
>500
HZSM-5
H
O
O - O
O Si + Al O
O
O
NPr + CH 2 =CH CH
3
3
PROPERTIES:
•CONTROL OF THE POPULATION OF ACID SITES: ONE SITE EACH FRAMEWORK Al
•ACID STRENGTH DISTRIBUTION
•SUPERACIDIC BEHAVIOR AT HIGH TEMPERATURES
•ALSO LEWIS SITES
Zeolites and Petrochemistry
• Fluid Catalytic Cracking
– Conversion of Gas Oil into Gasoline
• Reforming
– Increase of octane number (Quality of gasoline)
• Alkene Alkylation
– Gasoline with high octane number
Catalysis: Zeolites
Disproportionation of Toluene Using HZSM5
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
+
xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Shape selectivity allows only p-xylene to pass through
Solvent Replacement in Green Chemistry
• Volatile organic solvents are the normal media for
carrying out organic syntheses and extractions - usage
£4,000,000,000 p.a.
• Also used in products- paints, varnishes, cleaning agents,
adhesives
• VOC’s causing considerable environmental concern!
(Global warming/Ozone Depletion)
Solvent Replacement in Green Chemistry
Benzene
• Excellent solvent but it is a Genotoxic
human carcinogen
• Limit in drinking water of 5ppb(US EPA)
• In 1990 Perrier water found to have 1220ppb (cigarette smoke has 2000 times
more benzene than this) - 160 million
bottles withdrawn
• EU limit in petrol 5% before 2000, now
<1%
Solvent Replacement in Green Chemistry
Halogenated Solvents
Dichloromethane CH2Cl2:
• a suspected human carcinogen
• widely used in synthesis and extractions
• extraction of caffeine from coffee (<10ppm residue)
Perchoroethylene CCl2CCl2:
• a suspected human carcinogen
• main use in dry cleaning(85% of all solvents)
• also found in printing inks, typewriter correction
fluid and shoe polish
Solvent Replacement in Green Chemistry
Carbon Dioxide
Compound
Critical temperature
(oC)
Critical pressure
(Bar)
Carbon dioxide
31
73.8
Ethane
32.3
48.8
Water
374.0
220.6
scCO2 is inexpensive,
non-flammable and
non-toxic.
Current applications
include:
• Decaffeination of coffee
-replacing
dichloromethane
• Dry Cleaning
CO2 for Dry Cleaning
Dry
Cleaning
 current
process uses perc
(perchloroethylene), a suspected
carcinogen and groundwater contaminant
 new process uses liquid carbon dioxide, a
nonflammable, nontoxic, and renewable
substance
Other solvents
• Perfluorinated solvent
– Fluorous media
• Ionic Liquids
• Water
• Solventless reactions
– High conversions are needed
Perfluorinated solvents
R1
R2 Si
P
R3
R1
Si R2
R3
Si
R 2 R3
R
1
R1, R2, R3: CH3 or -CH 2CH 2CnF 2n+1
fluorinated triarylphosphines
F (2n+1)C
F(2n+1)C
N
N
N
N
CnF(2n+1)
CnF(2n+1 )
fluorinated cyclam
Ionic Liquids
+ N
R
R N
AnN,N'-dialkylimidazoliums
-
Cl
AlCl3
+
N
R
An-: PF6-, BF4-, Cl-, etc.
An-
N-alkylpyridinium
AlCl4-
AlCl3
Al2Cl7-
Real-World Cases: Microbes as
Catalysts
 Synthesis
of adipic acid and catechol from
renewable feedstocks using genetically
modified E. coli
 Applications
 Catalysis/biocatalysis
 Renewable
feedstocks
 Waste water remediation
Catalysis
Activity + selectivity, higher throughput with
less waste, less energy
Propeneamide is the first bulk chemical manufactured
using an industrial biotransformation:
N
O
5 degrees C
pH 7.5
99.99% Yield
NH2
The active enzyme is nitrile hydralase in whole cells of
Rhodococcus rhodochrous, immobilised on
poly(propeneamide) gel
Catalysis
Membrane Technology
Extractive Membrane Bioreactor
Biomedium
Detachment
Dissolved Oxygen
Nutrients
Attachment
B
I
O
F
I
L
M
M
E
M
B
R
A
N
E
Wastewater
Pollutants
Membrane Technology
Extractive Membrane Bioreactor
New Stripper-BioScrubber plant on
site at Atofina Widnes
(Project initiated in March 2000)
Removals of benzene or toluene
from 500-1000 mg L-1 to less than
1ppm from point source waste
stream
Membrane Separations in Green Chemical
Technology
Biotransformations
Membrane Bioreactor for Biotransformations
Aqueous Phase
Whole cells or
enzymes as
biocatalysts
R
R
P
P
C
Organic Phase
R = Reactant
P = Product
Nonporous
membrane
Nanoporous membranes
• Is it possible to filtrate molecules?
a) No-crosslinked PDMS polymer
Me
Me
Me
Me
Si O Si O Si O Si
Me
Me
Me
Me
n
Me
Me
Me
Me
H Si O Si O Si O Si H
Me
Me
Me
Me
+
m
H B H
A
catalyst
A
B
CH2CH2
H
(linear PDMS)
b) Crosslinked PDMS polymer
Me
Me
Me
Me
Me
Me
Si O Si O Si O Si O Si O Si O Si
Me
Me
Me
Me
Me
Me
Me
n'
n
+
Me
Me
Me
H
Me
Me
Me
H Si O Si O Si O Si O Si O Si O Si H
Me
Me
Me
Me
Me
Me
Me
n'
n
catalyst
H
B
H
CH2CH2
A
CH2CH2
B
H
CH2CH2
(crosslinked PDMS)
A
Nanoporous membranes to filtrate
molecules
PDMS membrane
Hydrophilic
phase
H2O
H2O2
H2O2
H2O
H2O2
Hydrophobic
phase
Nanoporous membranes to filtrate
molecules
HO
Aqueous phase
Organic phase
OH
* R
H2O
O
O
* R
* R
(R and S)
Aqueous phase
H2O
HO
OH
* R
Nanoporous membranes to filtrate
molecules
N
But
Co
N
O
t
Bu
t
Bu
OAc t
Bu
Nanopores of Anodisk
ZSM-5 continuous film
Renewable Resources
• Biodiesel
– Synthesis of biodiesel from vegetable oil
– Properties of biodiesel
– Potential of biofuels
Polylactic Acid
 Manufactured from renewable resources
 Corn or wheat; agricultural waste in future
 A new thermoplastic polymer family based on
polylactic acid developed by Cargill Dow
 144,000 tpa plant built in Nebraska USA
 Potential market approaching 500,000 metric
tons per year.
 Uses 20-50% fewer fossil fuels than conventional
plastics
 PLA products can be recycled or composted
Cargill Dow
Designing Safer Chemicals
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
PPG Industries
2001 Designing Safer Chemicals Award Winner
Alternative Reagents
 Chlorine-free
wood pulp bleaching
 TAML catalysts activate hydrogen peroxide
 Eliminates formation of chlorinated organics
Collins, Carnegie Mellon University
H
H
OO
X
N
N
Cat+
Fe
X
N
O
III
N
O
_
Cat+ = Li+, [Me4N]+, [Et4N]+, [PPh4]+
O
X = Cl, H, OCH3
Agrochemicals
Pesticides
• Insecticides (wide spectrum, juvenile and sexual
hormones traps)
• Fungicides
• Herbicides (natural defense)
• Rodenticides
O
C
Cl
+
Cl
Cl
H
Cl
H+
Cl
Cl
Cl
Cl
Cl
-HCl
Cl
Cl
Cl
Cl
Pesticide generation
1. First Generation Pesticides: toxic
metals.
2. Second Generation Pesticides: synthetic
organic pesticides e.g. chlorinated
hydrocarbons such as persistent DDT.
3. Nonpersistent pesticides (e.g.
malathion, aldicarb).
4. Pheromones and insect hormones
4.- PESTICIDAS CLORADOS
H
Cl
Cl
Cl
C C
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
DDT
Cl
Cl
LINDANO
Cl
Cl
Cl
Cl
Cl
Cl
O
Cl
Cl
Cl
Cl
ALDRIN
Cl
Cl
Cl
DIELDRIN
Cl
Cl
Cl
Cl
CLORDANO
•Activity against carbonic anhydrase
enzyme
Pest resistance and Biomagnification
•
•
•
•
•
Total impact of a pesticide depends on 1) toxicity, 2)
dosage, 3) location
Pests develop resistance, may have far reaching
effects, and desirable insects also impacted.
Resurgences – pest population recovers and explodes
Secondary Pest Outbreaks – non-pests become pests
as loose natural enemies, gain resistance to pesticides
Biomagnification: multiplying effect of
bioaccumulation through the food chain. Chemicals
accumulate in lipids
Alternative Pest Control Methods
i.
v.
Control by natural enemies: lady bugs
Cultural control: non-chemical alteration of environmental
factors e.g. hygiene, crop rotation
vi. Natural Chemical Control (isolate, ID, synthesize then use
insects own hormones or pheromones to disrupt its life cycle.
Non-toxic and specific. Sex pheromones can be used to lead
insects into traps, or confuse them.
vii. Genetic Control: breed resistance crops using chemical (e.g.
Hessian fly on wheat) or physical barriers (e.g. hooked
hairs), sterile males (e.g. tsetse fly), biotechnology – genetic
engineering for transgenic crops (e.g. resistance to pest, or
resistance to broad-spectrum herbicide).
Insect Metamorphosis
Egg
Larva
Pupa
Adult
Changes are controlled by juvenile hormones
What are pheromones
• Pheromones are chemicals emitted by an
animal that signals another animal of the
same species.
• Example: female gypsy moths emit a
pheromone to attract a male
Pheromones and Pest Control
• Pheromones can be
utilized to catch or
deter insects
• Example:
Pheromone “traps”,
which contain the
pheromone emitted
by the female gypsy
moth can be set to
catch male moths
Examples of some Pheromones
CH2OH
Sexual pheromone of silk butterfly female
(E)10, (Z)12-Hexadecadienol
(Bombyx mori)
CH2 CH2 OH
(+)(z)2-Isopropenyl-1-methylcyclobutan-ethanol
Sexual pheromone of cotton worm
Green Chemistry Technologies and
Solutions
Conclusions:
Much still to do but Green Chemistry provides a
focus for:
• A pro-active approach to the increase in legislation (e.g.
emissions, Green House Gases taxes,restricted chemicals
list)
• A competitive advantage: beneficial in reducing
costs/risks and provide greater manufacturing flexibility
• An improvement in public image