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Green Chemistry: Principles and Practice
Mary M. Kirchhoff Summer School on Green Chemistry
and Sustainable Energy 23 July 2013
What Is Green Chemistry?
Green chemistry is the design of chemical products and processes that reduce or eliminate the use and generation of hazardoussubstances.
Growth in U.S. Environmental Regulations
AMFA ARPAA
AJA ASBCAA
ESAA-AECA FFRAA
FEAPRA IRA
NWPAA CODRA/NMSPAA
FCRPA MMPAA
120
110
100
90
80
70
60
50
40
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20
10
0
1870 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000
EPACT FFCA CERFA CRAA
PPA PPVA IEREA ANTPA GLCPA ABA CZARA WRDA EDP OPA RECA CAAA GCRA GLFWRA HMTUSA NEEA
SDWAA SARA
BLRA ERDDAA EAWA NOPPA PTSA UMTRCA ESAA QGA NCPA
TSCA FLPMA RCRA NFMA CZMAA
NEPA EQIA CAA EPA EEA OSHA FAWRAA NPAA
FRRRPA SOWA DPA
WSRA EA RCFHSA
AQA
NAWCA
WQA
NWPA
MPRSAA ARPA
HMTA
FCMHSA
NHPA
WLDA FWCAA
FWA AEA
AEPA FIFRA PAA
FAWRA MBCA NPS WA
IA NBRA
AA RHA YA
TA FWCA
BPA
NLRA WPA
AQA FOIA
WRPA AFCA
FHSA NFMUA
BLBA FWPCA MPRSA
CZMA NCA
FEPCA PWSA MMPA
ESA TAPA
RCRAA WLDI
APA SWDA
CERCLA CZMIA
COWLDA FWLCA
MPRSAA
CAAA CWA
SMCRA SWRCA SDWAA
Nu
mb
er
of
Law
s
12 Principles
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
Presidential Green Chemistry Challenge The Presidential Green
Chemistry Challenge was established to recognize and promote fundamental and innovative chemical technologies that accomplish pollution prevention through source reduction and that are useful to industry.
E-factor
Weight of byproducts/weight of desired product – Oil refining 0.1 – Bulk chemicals <15 – Fine chemicals 5-50– Pharmaceuticals 25-100+ Sheldon, Chem Tech, 1994, 24, 38.
Aprepitant Synthesis
Doubles yield Eliminates 340,000 L of waste/ton product Merck
N
O OH
O
Ph
CF3
CF3
OH
HN
NH
N
ClO
BrMg
F
CF3
CF3
OO
N
F
NHN
NHO
Aprepitant Statistics
85% reduction in raw materials use 80% reduction in water usage 85% reduction in waste 75% lower manufacturing costs E-factor
– Reduced from 477 to 66
Principle 2 Synthetic methods should be designed to maximize
the incorporation of all materials used into the
final product.
Atom Economy
Atom economy =MW of desired product
Sum of MWs of all substances produced
Diels-Alder Reaction
+
O O
100% Atom economy
Wittig Reaction
O
+ CH2Ph3P+ _ CH2
+ Ph3P=O
35% Atom economy
Atom Economy
Traditional synthesis of ibuprofen – 6 stoichiometric steps – <40% atom utilization
(CH3CO)2O AlCl3
O
ClCH2CO2C2H5
NaOC2H5
O CHCO2C2H5
H+
H2O
CHO
H2NOH
CH NOH
CN CO2H
Ibuprofen
Atom Economy
Catalytic synthesis of ibuprofen – 3 catalytic steps – 80% atom utilization (99% with recovered acetic acid) BHC
(CH3CO)2O HF
O
H2catalyst
OH
CO, Pd
CO2H
Ibuprofen
Principle 3 Wherever practicable, synthetic methodologies
should be designed to use and generate substances that possess little or no
toxicity to human health and the environment.
Alternative Reaction Conditions
Sodium iminodisuccinate
Biodegradable, environmentally friendly chelating agent
Synthesized in a waste-free process
Eliminates use of hydrogen cyanide Bayer Corporation and Bayer AG
O
O
O
NaOH NH3 ONa
ONaNaO
NaON
H
O O
O O
Principle 4 Chemical products should
be designed to preserve efficacy of function while
reducing toxicity.
Safer Chemicals: Reduced VOC Paints Coalescent: added to paint to provide a
smooth, continuous finish 120 billion lbs volatile coalescents lost to
atmosphere in U.S. each year Archer Daniels Midland
O
OH
O
O
OH O
Archer RC propylene glycol monoester
2, 2, 4-trimethyl-1, 3-pentanediol monoisobutyrate
Spinetoram
Produced by fermentation of renewable feedstocks using Saccharopolyspora spinosa Dow AgroSciences
Evolution of a Greener Technology Technology Technology 1999: Spinosad (Dow AgroSciences)
– Selective, environmentally-friendly insecticide
2008: Spinetoram (Dow AgroSciences) – Controls wider range of pests at lower use
rates than Spinosad 2010: Natular® Larvicide (Clarke)
– Spinosad-based mosquito larvicide that slowly releases in water (Sequential Plaster Matrix)
Principle 5 The use of auxiliary
substances (e.g. solvents, separation agents, etc.)
should be made unnecessary wherever
possible and, innocuous when used.
Benign Solvents: H2O
Carbon-carbon bond formation in water – Diels-Alder, Barbier-Grignard
Indium-mediated cyclopentanoid formation Li, McGill University
R2
O O Cl Cl
base
O
R2
O
Cl
R1
R1In/H2O
OH
R2
OR1
Benign Solvents: CO2
Organic reactions in sc-CO2
Partnership between the University of Nottingham and the Thomas Swan & Company
O
Pd / supportH2 / scCO2
O
Principle 6 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.
MAX HT™ Bayer Sodalite
Scale Inhibitor
Bayer process: converts bauxite ore to alumina
Problem: aluminosilicate crystals build up in heat exchangers/pipes – Decreases efficiency of heat exchange – Requires cleaning with H2SO4
MAX HT™ inhibits crystal formation
Annual savings per plant: $2-20 M, 9.5-47.5 trillion BTU Cytec
Principle 7 A raw material of
feedstock should be renewable rather than
depleting wherever technically and
economically practicable.
Maximyze® Enzymes
Cellulase enzymes produced by fermentation from renewable resources
Improved paper strength – Reduces wood pulp needed – Increases use of recycled paper – Decreases energy use – Reduces use of chemicals added to
improve paper strength Buckman
Renewable feedstocks
Conversion of waste biomass to levulinic acid
paper mill sludge, municipal solid waste,
unrecyclable waste paper, agricultural residues
Biofine, Incorporated
OH
O
O
levulinic acid
OO
OO
OH
O
OH
O
O
NH2
OHOH
O
O
C CH2CH
2CO
2HCH
3
OH
OH
-butyrolactone
methyltetrahydrofuran tetrahydrofuran
acrylic acid
-amino levulinic acid
diphenolic acid
succinic acid
Principle 8 Unnecessary derivatization
(blocking group, protection/deprotection,
temporary modification of physical/chemical
processes) should be avoided whenever possible.
Boric-Acid Mediated Amidation
Direct amidation of carboxylic acids with amines – Boric acid: nontoxic, safe, inexpensive – Eliminates use of SOCl2, PCl3, phosgene – Widely applicable Emisphere Technologies, Inc
R OH
O
H NR'
R'' R N
O
R'
R''
H2O+cat B(OH)3toluenereflux
+
Catalysis for Green Polymers
Metal-free organic catalysts applied to the synthesis and recycling of polyesters
Waymouth & Hedrick
Greener Manufacture of Sitagliptin Sitagliptin, active ingredient in Januvia™
– Treatment for Type II diabetes, controls blood sugar without significant side effects
– Transaminase-based process with broad applications for converting ketones to chiral amines
Merck & Codexis
N
F
F
F
NH2 O
NN
N
CF3
Principle 10 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.
Biodegradable Polymers CO and CO2 used as monomers Catalyst exhibits high activity and high
turnover number
Coates
Principle 11 Analytical methodologies
need to be further developed to allow for real-time, in-process monitoring
and control prior to the formation of hazardous
substances.
Protein Testing
Automated protein tagging technique – Tags amino acids commonly found in
proteins Employs non-toxic solutions Generates no hazardous waste
– Replaces hazardous materials and high temperatures in traditional methods
– Applications in the food and pet food sectors
CEM Corporation
Principle 12
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.
2008 Small Business Winner
Stabilized Alkali Metals – Alkali metals encapsulated in nanoscale porous
metal oxides Increased safety, decreased storage and
handling requirements Applications
– Pharmaceutical/industrial – Processing water into hydrogen fuel – Remediation SiGNa Chemistry, Inc.
Sustainable Development
Development that meets the needs of the present without compromising the ability of future generations to meet their own needs.
Brundtland Commission
Green Chemistry and Sustainability Green chemistry is
a tool in achieving sustainability – Not a solution to all
environmental problems
– Fundamental approach to pollution prevention
– Chemistry’s unique contribution to sustainability
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