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GREEN CHEMISTRY

Name : Miss. Madhavi U. Tale.Class : M.sc. 2nd sem.

J.B.COLLEGE OF SCIENCE ,WARDHA.

1. Past Accidents2. Development of “GREEN CHEMISTRY”3. 12 Principles of Green chemistry4. Multicomponent Reactions5. Applications of Green chemistry in

our day to day life6. Conclusion7. Reference

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At least 13 fires have been reported on the Cuyahoga River before June 22, 1969

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Industrie Chimiche Meda, Societa, Azionaria (ICMESA)

• Exposure to 2,3,7,8- tetrachlorodibenzo-p-dioxin (TCDD) in residential populations (> 100 ppm). • Normal concentration <1 ppm.

Seveso, Italian Dioxin crisis.July 10, 1976 in Lombardy ( Seveso )

Seveso Disaster

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Chernobyl: Russian Nuclear Power Plant explosion

April 26, 1986

Exposure of 185-250 million curie of radioactive material

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In 1991 Green Chemistry was introduced by Prof. Paul Anastas (Father of Green Chemistry).

A MISSION to make

Chemistry/Chemicals

safe and hazardless to the maximum extent.

Development of Green Chemistry

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WHAT IS GREEN CHEMISTRY?

THE DESIGN

OF CHEMICAL PRODUCTS AND PROCESSES

THAT REDUCE OR ELIMINATE THE USE AND GENERATION OF

HAZARDOUS SUBSTANCES .

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In 1997Prof. Paul Anastas & Prof. John Warner suggested 12 principles of environmental friendly chemistry called Green Chemistry

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PRINCIPLE :1. “It is better to prevent waste than to treat or clean

up waste after it is formed”

CHEMICAL PROCESS

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If the chemical reaction of the type

A + B P + W

Find alternate A or B to avoid W

Ex. Cyclohexene Adipic acid

The reaction involved corrosive conc. HNO3 which

causes evolution of oxides of nitrogen,

Hydrogen peroxide can be use

instead of Nitric acid as oxidizing agent .

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PRINCIPLE :2Atom Economy (Barry Trost)

Method should be designed to maximize the incorporation of all materials used in the process into the final product.

Atom Economy = M.wt. of desired productSum of MW of reactants used

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Atom Economic ReactionsExamples:

• Addition reaction

•Rearrangement reaction

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Addition ReactionsR

R

H

H+ HBr

R

R

CH3

Br

% Atom Economy = 100%

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Rearrangement REACTIONEx. Claisen Rearrangement

O

200OC

OH

OH

Product 134

Phenyl allyl ether ( Reactant ) 134

134% Atom economy = 100 ------ = 100 % 134

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Atom Uneconomic Reactions

Examples:•Substitution reaction

•Elimination reaction

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H3C(CH2)4

CH2

OH+ SOCl2 H3C

(CH2)4

CH2

Cl + SO2 + HCl

102 119 120.5 64 36.5

Substitution Reaction(Atom Un-economic)

120.5% Atom economy = 100 ----------- = 54.5% 102+119

SO2 and HCl are unwanted by products reducing the overall atom economy.

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Elimination Reactions

H3CHCBr

H2C CH3 t-BuOK

-HBrH3C C

HCH

CH3 KBr t-BuOK

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122

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56% Atom economy = 100 ----------- = 45.9% 122

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Principle : 3 Less Hazardous Chemical Syntheses

synthetic methods should use and generate non toxic substances

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Polycarbonate Synthesis: Solid-State Process

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Principle : 4 Design Safer Chemicals

Chemical products/process designed should not cause hazards to human health and environment.

• Perchloroethylene (“perc”) is the solvent most widely used in dry cleaning clothing.

• Perc is suspected of causing cancer and its disposal can contaminate ground water.

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A SAFER METHOD OF DRY CLEANING

• Liquid CO2 can be used as a safer solvent if a wetting agent is used with it to dissolve grease.

• This method is now being used commercially by some dry cleaners.

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Principle : 5Selection of Appropriate Solvents

The use of auxiliary substances should be made unnecessary whenever possible and innocuous when used.

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Common Organic Solvents & Toxicity

Benzene - Carcinogenic Toluene - Adverse effect on Liver & KidneyCCl4 - Carcinogenic CHCl3 - Cancer suspect agent CH3CN - Very Toxic(CH3)2 NCOH (DMF) - Irritant, Cause birth defectC4H8O (THF) - Irritant, Cause headache, Nausea

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Issues with Common Organic Solvents

Direct Issues: Indirect Issues:

• Toxicity

• Flammable

• Volatile

• Carcinogenic

• Expensive

• O3 depletion

• Global worming

• Environmental persistent

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What is Green Solvent ?

• Non halogenated• Non flammable• Non hazardous• Non toxic (Safe for people/environment) • BP < 200o C• Biodegradable/Recyclable

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Principle:6. Maximize Energy Efficiency

Energy requirements of process should be recognized for their environment and economic impact should be minimized.

Heating of systemCoolingStirring for proper mixingDistillationCompressionPumping of solventSeparation of products

Fossil fuelCO2 to atmosphere

Global warming

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Microwave Synthesis

Conventional heating procedure takes 18 Hr

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A raw material or feedstock should be renewable rather than depleting whenever technically and economically practical.

Principle : 7 Use of Renewable Feedstocks

Due to the over exploitation of natural resources, they are being depleting at enormous rate.

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Ethyl Lactate: A Renewable Solvent

Derived from processing of corn. Variety of lactate esters possible.

Attractive solvent properties• Biodegradable • Easy to recycle• Non-corrosive• Non-carcinogenic• Non-ozone depleting • Good solvent for variety of process• Commonly used in the paint and coating industry.

CH3-CH-C-OC2H5

OOH

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Raw Materials from Renewable Resources:The BioFine Process

Paper mill sludge

Agricultural residues,Waste wood

Municipal solid wasteand waste paper

O

HO

O

Levulinic acid

Green Chemistry Challenge Award1999 Small Business Award

Levulinic acid as a platform chemical

O

H2NOH

O

O

HO

DALA (-amino levulinic acid)(non-toxic, biodegradable

herbicide)

O

HO

O

OH

C

CH3

CH2

CH2

C

O

OHHO

Diphenolic acid

Acrylic acidSuccinic acid

O

THF

O

MTHF(fuel additive)

HOOH

butanediol

OO

gamma butyrolactone

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Principle :8 Reduce Derivatization

Unnecessary derivatization

should be minimized / avoided if possible

because such steps require additional reagents.

Fewer steps

Fewer hazardous materials

Less risk of exposures to employee's

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The Boots Company Synthesis of Ibuprofen (1960)

Production of 2 L of Ibuprofen generates 3 L of waste AE = 40%

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BHC Synthesis of Ibuprofen (1992)

3 L of IbuprofenGenerates less than one Liter of wasteAE = 70%

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Principle : 9 Use of Catalysts

90% Chemical Products Involve Catalyst in their Process

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Principle:10 Design for Degradation

(Related to Sustainability)

Chemical products should be designed so that at the end of their function they do not persist in the environment and should degrade into harmless substance

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Principle : 11. Real Time Analysis

Analytical methodologies need to be further developed

to allow for real time–in-process monitoring & control prior to the formation of hazardous substance.

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•Real time analysis for a chemist : The process of checking the progress of chemical reactions.

•Real-time monitoring allows for assurance of proper reaction condition

• More control >>> less risk of generating unwanted products.

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Principle : 12. Accident PreventionSubstance used in a chemical process should be chosen so as to minimize the potential for chemical accidents, including releases, explosions, fires.

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APPLICATION OF IN DAILY LIFE

1.Microscale technique

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2. A new foam : Pyrocool FEF

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3. Degradable PesticidesHarmful insecticide ex. DDT, they accumulate in plants and animals, causing damage to the final consumers humans.

A natural pesticide developed in India is a mixture of Jatropa, Neem, Custard Apple, and Pongamia seeds. This concoction is used to ward off pests without harming vegetables. It’s also commonly used on bananas, grapes, cotton, and sugarcane

50Biodegradable plastic utensils. Photodegradable plastic bag.

4.Degradable Plastics• Several types of degradable

plastics: biopolymers photodegradable plastics synthetic biodegradable plastics

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We should understand the important role of the green

chemistry and how to deal with it in our practical life

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ConclusionGreen chemistry Not a solution to all environmental problems But the most fundamental approach to prevent the pollution.

Each of us must take steps to protect our Earth's climate

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1.NEW TRENDS IN GREEN CHEMISTRY BY V.K. AHLUWALIA

2.GREEN CHEMISTRY BY AMIT GURTU

3.GREEN CHEMISTRY BY K.R.DESAI

Reference

THANK YOU QUESTION ? ? ?

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