for all my dear friends............

1. PREPARED BY
YASHRAJ CHAUHAN

2. INTRODUCTION
• Science based on research towards the
development of new sustainable processes
❖ DEFINITION
❖ Defined as the invention, design and
application of chemical products and processes
to reduce or to eliminate the use and
generation of hazardous substances

3. SIGNIFICANCE
➢ Major tool in accomplishing
Pollution prevention
➢ Leads to reduction in waste
➢ Reduced use of energy and other perishable
resources
➢ Carrying out chemical activities leading to safer
products

4. PRINCIPLES OF GREEN CHEMISTRY
➢ Term coined by Dr. Paul Anastas
known as the “Father of Green
Chemistry”
➢ He defined it as the utilization of a set of
principles that reduces or eliminates the
use or generation of hazardous substances
in the design, manufacture and application
of chemical products

5. 12 PRINCIPLES OF GREEN CHEMISTRY
1. Prevent waste
2. Atom Economy
3. Less Hazardous Chemical Synthesis
4. Designing Safer Chemicals
5. Use safer Solvents /reaction conditions
6. Increase Energy Efficiency.
7. Use of Renewable Feedstocks
8. Reduce chemical derivatives
9. Use catalysts
10. Design for Degradation
11. Real-time Analysis for Pollution Prevention.
12. Inherently Safer Chemistry for Accident Prevention

6. 1. PREVENT WASTE
➢ Design processes which minimize waste
➢ Better to prevent waste than to clean and treat it

7. 2. ATOM ECONOMY
➢ Atom economy =Mass of atoms in desired product x 100
Mass of atoms in reactants
➢ Concept developed by Barry Frost
➢ Evaluates the efficiency of a chemical transformation

8. ATOM ECONOMY
➢ CHOOSE TRANSFORMATIONS THAT INCORPORATE MOST OF
THE STARTING MATERIALS INTO THE PRODUCT INCREASES
THE EFFICIENCY AND MINIMIZES WASTE
Classic Route to Ibuprofen
Ac2O
AlCl3
COCH3
HCl, AcOH, Al W aste
ClCH2CO2Et
NaOEt
O
EtO2C
HCl
H2O / H+
OHC
AcOH
NH2OH
OHNN
H2O / H+
HO2C
NH3
Hoechst Route To Ibuprofen
O
HF
AcOH
Ac2O
H2 / Ni
OH
CO, Pd
HO2C

9. 3. LESS HAZARDOUS CHEMICAL SYNTHESIS
 Wherever practicable, synthetic methodologies
should be designed to use and generate
substances that possess little or no toxicity to
human health and the environment

10. LESS HAZARDOUS CHEMICAL SYNTHESIS
➢ Polycarbonate Synthesis: Phosgene Process
Disadvantages
➢ phosgene is highly toxic, corrosive
➢ requires large amount of CH2Cl2
➢ polycarbonate contaminated with Cl impurities
OH OH
Cl Cl
O
+
NaOH
O O *
O
* n

11. LESS HAZARDOUS CHEMICAL SYNTHESIS
➢ Polycarbonate Synthesis: Solid-State Process
➢ Advantages
➢ diphenylcarbonate synthesized without
phosgene
➢ eliminates use of CH2Cl2
➢ higher-quality polycarbonates
OH OH
+ O O *
O
* n
O O
O

12. 4. DESIGNING SAFER CHEMICALS
➢ Chemical products should be designed to
preserve efficacy of the function while reducing
toxicity

13. DESIGNING SAFER CHEMICALS
➢ Antifoulants are generally
dispersed in the paint as it is
applied to the hull.
➢ Organotin compounds have
traditionally been used,
particularly tributyltin oxide
(TBTO).
➢ TBTO works by gradually leaching
from the hull killing the fouling
organisms in the surrounding area
➢ Organotin compounds are
chronically toxic to marine life and
can enter food chain. They are
bioaccumulative.

14. 5. USE SAFER SOLVENTS/REACTION
CONDITIONS
➢ The use of auxiliary substances (solvents, separation
agents, etc.) should be made unnecessary whenever
possible and, when used, innocuous.

15. USE SAFER SOLVENTS/REACTION CONDITIONS
➢ Solvent Substitution
➢ Water as a solvent
➢ New solvents
 Ionic liquids
 Supercritical fluids

16. 6. INCREASE ENERGY EFFICIENCY.
➢ 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

17. 7. USE OF RENEWABLE FEEDSTOCKS
➢ A raw material or feedstock should be renewable
rather than depleting whenever technically and
economically practical

18. POLYHYDROXYALKANOATES (PHA’S)

19. RAW MATERIALS FROM RENEWABLE RESOURCES:
THE BIOFINE PROCESS
O
HO
O
Paper mill
sludge
Levulinic acid
Municipal solid waste
and waste paper
Agricultural
residues,
Waste wood
Green Chemistry Challenge Award
1999 Small Business Award

20. LEVULINIC ACID AS A PLATFORM CHEMICAL
O
HO
O
O
H2N
OH
O
O
HO
DALA (-amino levulinic acid)
(non-toxic, biodegradable herbicide)
O
HO
O
OH
C
CH3
C
H2
C
H2
C
O
OHHO
Diphenolic acid
Acrylic acid
Succinic acid
O
THF
O
MTHF
(fuel additive)
HO
OH
butanediol
O
O
gamma
butyrolactone

21. 8. REDUCE CHEMICAL DERIVATIVES
➢ Unnecessary derivatisation (blocking group,
protection/ de-protection, temporary
modification of physical/chemical processes)
should be avoided whenever possible
➢ Reduces atom economy

22. 9. USE CATALYSTS
➢ Catalytic reagents (as selective as possible) are
superior to stoichiometric reagents
➢ Readily regenerated, separated
➢ Recyclable
➢ Mild conditions

23. HETEROGENEOUS VS HOMOGENOUS
➢ Distinct solid phase
➢ Readily separated
➢ Readily regenerated & recycled
➢ Rates not as fast
➢ Diffusion limited
➢ Sensitive to poisons
➢ Lower selectivity
➢ Long service life
➢ High energy process
➢ Poor mechanistic understanding
➢ Same phase as rxn medium
➢ Difficult to separate
➢ Expensive and/or difficult to
separate
➢ Very high rates
➢ Not diffusion controlled
➢ Robust to poisons
➢ High selectivity
➢ Short service life
➢ Mild conditions
➢ Mechanisms well understood
Green
catalyst

24. 10. DESIGN FOR DEGRADATION
➢ Chemical products should be designed so that
at the end of their function they do not persist
in the environment and instead break down
into innocuous degradation products
➢ CFCs, DDT
➢ Biodegradable polymers

25. 11. REAL-TIME ANALYSIS FOR POLLUTION
PREVENTION
➢ Analytical methodologies need to be further
developed to allow for real-time in-process
monitoring and control prior to the formation of
hazardous substances
➢ Real time analysis for a chemist is the process of
“checking the progress of chemical reactions as it
happens.”
➢ Knowing when your product is “done” can save a
lot of waste, time and energy!

26. 12. INHERENTLY SAFER CHEMISTRY FOR
ACCIDENT PREVENTION
➢ Substance 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
➢ Various industrial accidents
➢ E.g: Bhopal gas tragedy