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KHOAHÓAHỌC VÀ CÔNG NGHỆTHỰC PHẨM 12/14/2012 The design of chemical products & processes that reduce or eliminate the use Discovery & application of new chemistry technology leading to pr

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 Agent Orange (2,3,7,8-TCDD):

2,4-D 2,4–dichlorophenoxyacetic acid 2,4,5-T

2,4,5-trichlorophenoxyacetic acid

2,3,7,8-TCDD 2,3,7,8-tetrachlorodibenzodioxin

↓

KHOAHÓAHỌC VÀ CÔNG NGHỆTHỰC PHẨM

Phản ứng hình thành Chất độc màu da cam (Orange agence)

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12/14/2012

The design of chemical products &

processes that reduce or eliminate the use

Discovery & application of new chemistry

technology leading to prevention reduction of environmental, health & safety

impacts at source

History

• Early 1990’s

Green Chemistry gained its current standing as a scientific discipline as well as

practical means to pollution prevention as the result of collaboration between

the US government, Industry, and Academia In the early 1990's, Paul Anastas,

who was then the chief of the Industrial Chemistry Branch at the US EPA,

moved forward the concept of Green Chemistry

• Mid 1990's

Paul Anastas and John Warner developed the 12 Principles of Green Chemistry:

a framework to help us think about how to prevent pollution when inventing

new chemicals and materials Paul Anastas and John Warner's work

founders of a new field called Green Chemistry, based on the productive

collaboration of government and industry, was just beginning.

• 1993

A white paper entitled "Chemistry for a Clean World," published by the

European Community's Chemistry Council in June, attracted a great deal of

in cleaner, cheaper, smarter chemistry This remains the only award given by the President of the United States specifically for work in chemistry.

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• 1998

John Warner and Paul Anastas published the seminal book Green Chemistry:

Theory and Practice, which gave a precise definition to Green Chemistry and

enumerated the Twelve Principles fundamental to the science The definition and

principles have become the generally accepted guidelines for Green Chemistry.

Since it was first published, the book has been re-printed in several languages.

• 1999

Great Britain's Royal Society of Chemistry publishes an international scientific

journal entitled Green Chemistry bimonthly; the first issue was published

February1999.The majority of the synthesis and process journals focus on papers

related to this topic.

• 2001

• 2006

The International Union of Pure and Applied Chemistry, formed a special

subcommittee on Green Chemistry and launched a bi-annual international

conference The first was held in Germany, the second in Russia, and the 2010

conference was slated for Canada.

• 2007 John Warner returned to industry to develop green technologies, partnering with Jim Babcock to found the first company completely dedicated to developing green chemistry technologies, the Warner Babcock Institute for Green Chemistry The Institute was created with the mission to develop nontoxic, environmentally benign, and sustainable technological solutions for society.

Simultaneously, John Warner founded a non-profit foundation, Beyond Benign, to promote K-12 science education and community outreach.

• 2009

In May 2009, President Barack Obama nominated Paul Anastas to lead the U.S.

Environmental Protection Agency's (EPA's) Office of Research and Development.

The nomination is a decisive achievement for the adoption and advancement of the principles of Green Chemistry.

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12/14/2012

The 12 principles of Green Chemistry

(Paul Anastas & John Warner)

 Prevention

It is better to prevent waste than to treat or clean up waste

after it has been created.



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Atom Economy:Example

Wherever practicable, synthetic methods should be

little or no toxicity to human health and

environment.

Chemical products should be designed to effect their

desired function while minimizing their toxicity

Atom Economy = (137/275) X 100 = 50%

 Safer Solvents and Auxiliaries

The use of auxiliary substances (e.g., solvents,

separation agents, etc.) should be made unnecessary

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10

 Design for Energy Efficiency

Energy requirements of chemical processes should be

recognized for their environmental and economic

impacts and should be minimized If possible,

synthetic methods should be conducted ambient

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A raw material feedstock should be renewable rather than depleting whenever technically and

Unnecessary derivatization (use blocking groups,

protection/ deprotection, temporary modification of

physical/chemical processes) should be minimized or

avoided if possible, because such steps require

Catalytic reagents (as selective possible) are superior to stoichiometric reagents.

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12/14/2012

 Design for Degradation

Chemical products should be designed so that at the

end of their function they break down into innocuous

degradation products and not persist in the

environment.

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 Real-time analysis for Pollution Prevention

Analytical methodologies need to be further developed to allow

for real-time, in-process monitoring and control prior the

formation of hazardous substances.

Condensed Principles of green chemistry

( Samantha Tang, Richard Smith and Martyn Poliakoff )

 Inherently Safer Chemistry for Accident Prevention

Substances and the form of a substance used in a chemical

process should be chosen to minimize the potential for

chemical accidents, including releases, explosions, and fires.

3.Less Hazardous Chemical Syntheses

Wherever practicable, synthetic methods should be designed to use and generate substances that possess little or

no toxicity to human health and the environment

4.Designing Safer Chemicals

Chemical products should be designed to effect their desired function while minimizing their toxicity

5.Safer Solvents and Auxiliaries

The use of auxiliary substances (e.g., solvents, separation agents, etc.) should be made unnecessary whereverpossible and innocuous when used

6.Design for Energy Efficiency

Energy requirements of chemical processes should be recognized for their environmental and economic impactsand should be minimized If possible, synthetic methods should be conducted at ambient temperature andpressure

7.Use of Renewable Feedstocks

A raw material or feedstock should be renewable rather than depleting whenever technically and economicallypracticable

8.Reduce Derivatives

Unnecessary derivatization (use of blocking groups, protection/ deprotection, temporary modification ofphysical/chemical processes) should be minimized or avoided if possible, because such steps require additionalreagents and can generate waste

9.Catalysis

Catalytic reagents (as selective as possible) are superior to stoichiometric reagents

10.Design for Degradation

Chemical products should be designed so that at the end of their function they break down into innocuousdegradation products and do not persist in the environment

11.Real-time analysis for Pollution Prevention

Analytical methodologies need to be further developed to allow for real-time, in-process monitoring and controlprior to the formation of hazardous substances

12.Inherently Safer Chemistry for Accident Prevention

Substances and the form of a substance used in a chemical process should be chosen to minimize the potential

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The Twelve Principles of Green Engineering*

Inherent Rather Than Circumstantial

Designers need to strive to ensure that all materials and energy inputs and outputs are as inherently

nonhazardous as possible

Prevention Instead of Treatment

It is better to prevent waste than to treat or clean up waste after it is formed

Design for Separation

Separation and purification operations should be designed to minimize energy consumption and materials use

Maximize Efficiency

Products, processes, and systems should be designed to maximize mass, energy, space, and time efficiency

Output-Pulled Versus Input-Pushed

Products, processes, and systems should be "output pulled" rather than "input pushed" through the use of

energy and materials

Conserve Complexity

Embedded entropy and complexity must be viewed as an investment when making design choices on recycle,

reuse, or beneficial disposition

Durability Rather Than Immortality

Targeted durability, not immortality, should be a design goal

Meet Need, Minimize Excess

Design for unnecessary capacity or capability (e.g., "one size fits all") solutions should be considered a design

flaw

Minimize Material Diversity

Material diversity in multicomponent products should be minimized to promote disassembly and value

retention

Integrate Material and Energy Flows

Design of products, processes, and systems must include integration and interconnectivity with available

energy and materials flows

Design for Commercial "Afterlife"

Products, processes, and systems should be designed for performance in a commercial "afterlife."

Renewable Rather Than Depleting

Material and energy inputs should be renewable rather than depleting

* Anastas, P.T., and Zimmerman, J.B., "Design through the Twelve Principles of Green Engineering", Env Sci

and Tech., 37, 5, 94A-101A, 2003

Efficient use of (preferably renewable) raw materials,

Elimination of wasteful byproducts,

Avoiding use of toxic/hazardous reagents and solvents,

Use of safer final (biodegradable) products, and

Increasing energy efficiency.

Two considerations that dominated green chemistry are:

A Maximum atom utilization,

B The minimum waste produced (E-Factor).

The waste includes byproducts, reagents,

solvent loss and even fuel.

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SỰ XÚC TÁC VÀ HÓA HỌC XANH

Why is catalysis important in making industrial

processes more efficient and economically profitable?

•Catalytic reagents reduce the energy of the

transition state, thereby reducing the energy input

required for a process.

•Catalysts are required in small quantities.

•The regeneration and reversibility of catalysts are

No catalyst

With catalyst

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Insimpleform,itdefinedas:

(Chemicalsin(kg)-Desiredproduct(kg))Totalproduct(kg)

Theenormouswasteindifferentsegmentsofindustryareshowninthetablebelow

Catalyst

Stoichiometric

reagents

M.Lancaster,“GreenChemistryAnIntroductoryText,Roy.Soc.Chem.,cambridge, 2002

A higher Efactor→ more waste → greater negative

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•Ill-defined catalytic species

•Limited Range of Reactions

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Using homogeneous catalyst

•More waste

•Less possibility recycle and

reuse

•Product contaminated with toxic

metals

Catalyst separation by column

chromatography distillation extraction

Using homogeneous catalyst

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Soluble polymer-supported catalyst

•Temperature-dependent phase separation

Catalyst

• Solvent-dependent phase separation

• PEG: soluble in DMF, DCM but insoluble in ether, iPrOH

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Biocatalysts

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•Other chemically sensitive functional groups → still survive with enzyme

•Biocatalytic conditions → cleaner greener still

•Side-reactions avoided → advantageous for product purifications

•Enzyme → react on a single type of functional group only

Q factor

the waste For example, sodium sulphate as a waste is certainly far less harmful than cyanide waste A new term

environment quotient (Q) has been coined to emphasize this

different wastes according their extent their harmful effect.

R.A.Sheldon,Chemtech.,38,(1994)

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+ C2H2 HZSM-5

Catalysis with acidic zeolites

Similarly, propylbenzene could be manufactured using a 3-dimensional

dealuminated mordenite (3-DDM) catalyst

+dealuminated

mordenite

Si/Al = 100-1000

Dealumination enabled to obtain very high Si:Al ratio (up to 1000) In these

form, the micropores of mordenite were connected through mesopores

(5-10 nm). K.TanabeandW.F.Holderich, Appl.Catal.A General,181,399(1999)

1 ALKYLATION: Mobil-Badger Process (Polyalkylation is suppressed)

O

G.R.Meima,G.S.LeeandJ.M.Garces,in“FineChemicalsThroughheterogeneous

Catalysis(Ed.R.A.Sheldon,Wile-VCH,Weinheim,2001

Acylation

A.VogtandA.Pfenninger,EP0701987A1,1996toUetikonAG

Hydroxyalkylaton using zeolites is difficult because unfavourable

adsorption ratio of the reagent and the substrate This difficulty is avoided

by having the aromatic and the epoxide functions in the same molecule

H-ZSM-5

or H-Beta

O

J.A.Elings,R.S.DowningandR.A.Sheldon,Stud.Surf.Sci.Catal,105,1125(1997)

Ce3+ exchanged Yzeolite could catalyze toluene and xylenes using with higher

Formation of N-heterocycles by intermolecularcyclization is catalyzed acidic zeolites

Synthesis pyridine and picoline from amixture of acetaldehyde, formaldehyde andammonia in presence H-ZSM-5 is example

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Cl

H+

NHCH3NH2

select 98% 97-100%

Epoxidereaarangement( key stepinthemanufactureofmany intermediates in

thefinechemicalindustry Traditionalmethodusedstoichiometric Lewis acids

or bases

O

G P.Heitmann, G Dahlhoffand W.F.Holderich, J.Catal,186,,12(1999)

Traditional method for preparing 2,6-dichlorobenzonitrile uses stoichiometric Amonts

chlorine, HCN and POCl3 with atom efficiency31% The newprocess Was developed uses

zeollitecatalystsEur.Pat.Appl.EP948988(1999)

+ Cl2

ClCl

Cl

CN

Cladsorption in

faujasit eCl

Traditional methods of oxidation in organic chemistry uses stoichometric reagents (salts ofmanganese and

chromium.Thenewchemistrytriestousemolecularoxygenorhydrogenperoxide.TiO2supportedonsilicawasnot effective with hydrogen peroxide because the water produced gets strongly adsorbedo on silica TS-1 hasbeen used successfully because this titanium substituted silicalite-1 hydrophobic Phenol converted withhydrogen peroxidetoamixtureofhydroquinoneandcatechol.Rhone-PoulencProcessusesperchloricacidandphosphoric acidwhereas EnichemprocessusesTS-1.Acomparision givenhere

Comparision of phenol conversion processes

Process (catalyst) Rhone-Poulenc (H 3 PO 4 ,HClO 4 )

Alrge numberofbulkchemicalsareproducedbyusingmolecularoxygeneither intheliquid

orinthevapourphasereaction.S0meoftheseare:

Benzene/ethene tostyrene,p-xylene toterephthalic acid,formaldehydetomethanol,Ethene

toetheneoxide, n-butanetoaceticacid,propene toacrylonitrile, n-butanetoMaleicanhydride,

o-xylene tophthalicanhydride, isobutenetomethylmethacrylateetc

Molecularoxuygenisaspintriplet anditsdirect reactiontoaorganicsinglet compoundis

spinforbidden Toovercomethis,thetriplet isallowed toreactwithparamegnetic Metalions

formingasuperoxo-metalcomplexthatformsavarietyofmetal-oxygen species

Use of catalytic route to selective oxidation in presence of several functional groups is A big

challenge

K.Iwayama,S.Yamakawa,M.KatoandH.Okino,Eur.Pat.Appl.EP948988(1999)toToray

Bayer-Villiger Oxidation (conversion of ketone or an aldehyde to the ester)

Theperacidundergoes nucleophylic attack on thecarbonyl groupgivimgan inetrmediate.Inthenextstep,

concertedmigrationofoneofthealkylgroupstakesplacereleasingtheCarboxylateanion.Thereactioniswidely

usedinorganic chemistry Zeolitebetacontaining 1.4wt%oftinisagoodcatalystusinghydrogen peroxide

aromatics

+ NCCH2CO2Et Na-X

CN

Chemicals throughHetero.Catal.,

CormmaandS.Iborrain“Fine

309(2001)

K-Y

CN CN

+ MeOH

K.R.Kloestra,H.vanBekkum,Chem

SIDECHAINALKYLATIONS

Comarattivelymuchlessattentionhasbeenpaidtobasiczeolites.Zeolitescanbemadebasicby1.Exchange

ofprotonswithalkaliorrareearthionsor2.bydepositingnano-particlesofalkalioralkaliearthoxidesinthepores.Thebasicsitesare weak.Theycanbe usedtogenerateC-Cbond inthesidechainsofsubstituted

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