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Solid Acid Catalysts
ZEOLITE-CATALYZED FRIEDEL-CRAFTS ACYLATION
O
AlCl3
O
+ CH3COCl
O
solvent
MeO
+ HCl
MeO
O
O
MeO
H-beta
+ (CH3CO)2O
O
MeO
+ CH3CO2H
ZEOLITE-CATALYZED FRIEDEL-CRAFTS ACYLATION
Homogeneous
AlCl3 >1 equivalent
Solvent (recycle) Hydrolysis of
products 85-95% yield
4.5 kg aqueous effluent per kg
12 unit operations
Heterogeneous
H-beta, catalytic & regenerable
No solvent
No water necessary
>95% yield /higher purity
0.035 kg aqueous
effluent per kg
3 unit operations
S. Ratton, Chem. Today (Chim. Oggi), March/April, 1998, 33
SALT-FREE ESTERIFICATION OF AMINO ACIDS
CONVENTIONAL:
NH3+
NH3+ Cl O-
HCl (1 eq.)
OH
R
MeOH/HCl (cat.)
O
R
+
NH3 Cl -
OMe
+ H2O
R
O
O
SALT-FREE ESTERIFICATION OF AMINO ACIDS
ZEOLITE-CATALYZED:
+
NH2
NH3
O-
OMe
MeOH, H-USY, 100 C
R
+ H2O
O
R
O
R = PhCH2 (aspartame intermediate); S/C = 20 (w/w), 83% yield (TON = 180)
Naphtha cracking catalyst (H-USY)
Opt. Active amino acids (partially) racemized
M.Wegman, J.M.Elzinga, E.Neeleman, F.van Rantwijk and R.A.Sheldon, Green Chem., 3,61,2001
Catalytic Oxidations
TS-1 CATALYZED OXIDATIONS WITH H2O2
Hydrophobic molecular sieve (5.6 x 5.3Å) / HI (Xoctane / XH2O) TS-1=3.4 ; Ti /
SiO2=0.1
NOH
O
O
NH3
R2CHOH
R2C
O
TS - 1
+
30% H2O2
PhOH
OH
OH
+
OH
OH
Enichem
B.Notari, Stud. Surf. Sci. Catal., 37 , 431 (1988)
Cyclohexanone Oxime Manufacturing Process
Current Process
Ammoximation Process
(NH4)2SO4
NOH
O
Oximation
NOH
Oximation
O
NH3
(NH3OH)2SO4
H2
H2O2
dil H2SO4
NO
Air
O2
NH3
H2
NH3
GREEN CHEMISTRY
DEFINITION
Green Chemistry is the utilisation 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 .
GREEN CHEMISTRY IS ABOUT
•
•
•
•
•
•
Waste Minimisation at Source
Use of Catalysts in place of Reagents
Using Non-Toxic Reagents
Use of Renewable Resources
Improved Atom Efficiency
Use of Solvent Free or Recyclable Environmentally Benign
Solvent systems
Green Chemistry Is About...
Waste
Materials
Hazard
Risk
Energy
Cost
Why do we need Green Chemistry ?
• 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.
• Green chemistry looks at pollution prevention on
the molecular scale and is an extremely important
area of Chemistry due to the importance of
Chemistry in our world today and the implications it
can show on our environment.
• The Green Chemistry program supports the
invention of more environmentally friendly chemical
processes which reduce or even eliminate the
generation of hazardous substances.
• This program works very closely with the twelve
principles of Green Chemistry.
“It is better to prevent waste than to treat or clean
up waste after it is formed”
Chemical
Process
Human society is constantly facing such
environmental issues and problems, air
pollution, global climate change, soil and
water pollution, acid rain, depletion of
natural resources and accumulation of
natural hazardous waste
Green chemistry preventing pollution and
sustaining the earth
In this presentation the synthesis of ibuprofen by
Friedel-crafts alkylation of isobutyl benzene with
lactic acid and its derivatives was attmpted using
various acid catalysts like Zn-Zeolite-Y,
AlCl3/MCM-41, AlCl3/SiO2
Classic Route to Ibuprofen
H C l, AcO H , Al W aste
Ac 2 O
Ac O H
HCl
H 2 O / H+
C lC H 2 C O 2 Et
AlC l 3
Na O Et
C OC H 3
EtO 2 C
O HC
O
N H2 O H
H 2 O / H+
N
H O2C
OHN
Hoechst Route To Ibuprofen
AcOH
HF
H2 / Ni
CO, Pd
Ac2O
O
HO
HO2C
IBUPROFEN
OH
Is this possible and if
so how to effect this
reaction catalytic?
CH3
+
COOH
CH3
Lactic acid
CH3
CH3
COOH
CH3
First synthezised
By the Boots company in
Nottingham England in 1960s
IBUPROFEN
“The use of auxiliary substances (e.g. solvents,
separation agents, etc.) should be made unnecessary
wherever possible, and innocuous when used”
“Energy requirements should be
recognized for their environmental
impacts and should be minimized.
Synthetic methods should be conducted at
ambient pressure and temperature”
Heating
Cooling
Stirring
Distillation
Compression
Pumping
Separation
Energy Requirement
(electricity)
GLOBAL
WARMING
Burn fossil
fuel
CO2 to
atmosphere
“A raw material of feedstock should be renewable
rather than depleting wherever technically and
economically practical”
Non-renewable
Renewable
Resource Depletion
• Renewable resources can be made
increasingly viable technologically
and economically through green
chemistry.
Biomass, Carbon dioxide, Nanoscience,
Solar, Waste utilization
Poly lactic acid (PLA) for plastics
production
Polyhydroxyalkanoates (PHA’s)
The major uses of GREEN CHEMISTRY
•
•
•
•
•
Energy
Global Change
Resource Depletion
Food Supply
Toxics in the Environment
ENERGY
The
vast majority of the energy
generated in the world today is from
non-renewable sources that damage
the environment.
 Carbon



dioxide
Depletion of Ozone layer
Effects of mining, drilling, etc
Toxics
ENERGY
 Green
Chemistry will be essential in
developing the alternatives for energy
generation (photo-voltaics, hydrogen, fuel
cells, bio-based fuels, etc.) as well as
 continue the path toward energy efficiency
with catalysis and product design at the
forefront.

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
RESOURE DEPLETION
Due
to the over utilization of nonrenewable resources, natural
resources are being depleted at an
unsustainable rate.
Fossil fuels are a central issue.
RESOURCE DEPLETION
 Renewable
resources can be made
increasingly viable technologically and
economically through green chemistry.






Biomass
Nanoscience & technology
Solar
Carbon dioxide
Chitin
Waste utilization
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
FOOD SUPPLY
Green
chemistry is developing:
Pesticides which only affect target
organisms and degrade to innocuous byproducts.
 Fertilizers and fertilizer adjuvants that are
designed to minimize usage while
maximizing effectiveness.
 Methods of using agricultural wastes for
beneficial and profitable uses.

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.
Pollution Prevention Hierarchy
Prevention & Reduction
Recycling & Reuse
Treatment
Disposal
DDT
• However, DDT is soluble in organic
solvents…. and thus in animal fat. DDT
and or DDE have been detected in fat
deposits of all birds and fish that have
been analyzed including from those from
desert regions or ocean depths.
• In North America the average person has
3 ppm concentration of DDT/DDE in their
body fat.
DDT
• Concerns regarding its possible long term
health effects and its demonstrated
damage to the life cycle of birds lead to
the ban in most of western countries.
• (U S 1973)
CONCLUSION
• Green chemistry Not a solution to all
environmental problems But the most
fundamental approach to preventing
pollution