1. GREEN CHEMISTRY
Chemistry has an important role to play in achieving a
sustainable civilization on earth
(Prof. Terry Collins, Carnegie Mellon Univ)
2. HISTORY OF ENVIRONMENTAL PROTECTION
For decades, environmental protection has meant controlling
exposure to hazardous substances
The past managing Risk :
Historical focus
Risk = f(Hazard, Exposure)
3. GREEN CHEMISTRY- DEFINITION
Green Chemistry is the design of chemical products or processes
to reduce to eliminate the use of generation of hazardous substances
Why Green Chemistry?
Reduce costs (raw materials, energy)
Reduced need for capital investment
Reduce time to market
Encourage investors
Minimize unknown future liability
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6. GREEN CHEMISTRY PRINCIPLES
1. Prevention : it is best to prevent pollution / waste
2. Atom Economy: synthetic methods should maximize the
incorporation of all materials used in the process into the final
product
3. Less Hazardous Chemical Synthesis: synthetic methods should
use and generate nontoxic substances
4. Designing Safer Chemicals: products should be nontoxic &
designed to effect their desired function
5. Safer solvents and auxiliaries: auxiliary substances should be
avoided and innocuous when used
6. Design for energy Efficiency : run chemical reaction at ambient
temperature and pressure
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8. GREEN CHEMISTRY PRINCIPLES
7. Use of renewable feedstocks : raw material should be renewable
than depleting
8. Reduce derivatives: avoid unnecessary derivatization that require
additional reagents and can generate waste
9. Catalysis: Catalytic reagents (as selective as possible) are superior
to stoichiometric reagent which are used in excess and work only
once
10. Design for degradation: Chemical product should be designed
into degradable product
11. Analyze in the real time to prevent pollution: in process real-time
time monitoring to eliminate by product
12. Minimize accidents; design chemicals and their form to minimize
minimize the potential for chemical accidents, explosions, etc.
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12. TWO IMPORTANT FACTORS IN REAGENT SELECTION
a. Product selectivity
The higher conversion of raw material to the desired product
b. Product yield
The higher percentage of the desired product (stoichiometric
considerations)
1. Structural activity relationship
2. Oxidation (permanganate, dichromate, osmium tetroxida)
3. Reduction (LiH4Al)
4. Alkylation (attachment of alkyl group)
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22. FIVE EASY
THINGS YOU
CAN DO TO
MAKE YOUR LAB
MORE
SUSTAINABLE
Recycle
Recycle electronics, ice packs, packaging
materials, toner cartridges, pipette tip boxes,
and water purification cartridges.
Neutralize
Neutralize basic phosphate-buffered HPLC
waste or acidic HCl waste to pH 7 and pour
down the drain.
Switch
Switch to green solvents: Use 2-methyl
tetrahydrofuran in place of methylene chloride,
and use cyclopentylmethyl ether in place of
tetrahydrofuran, 1, 4-dioxane and ether.
Run Run experiments on the micro scale to
reduce waste.
Fume Close fume hoods when not in use to reduce
energy use.
