绿色化学课件第二章

Chapter2GreenChemistry

2.1

TheconceptofGreenChemistry

2.2PromotingthedevelopmentofGreenChemistry

2.3AtomEconomyofchemistryreaction

2.4AtomEconomyandenvironmentaleffects

2.5Researchareaofgreenchemistry2.1TheconceptofGreenChemistryGreenChemistryisinvestigatedworld-widelyCountriesandareaswithGreenChemistryinvestigationNoyori:ImportanceofGreenChemistryWithoutGreenChemistry,chemicalmanufacturingwillbeunabletosurviveintothe22ndcentury.

GreenChemistryTheconnotationofGreenChemistryAdeeperviewofGreenChemistryGreenChemistryisrealizableGreenChemistryisdifferentfromenvironmentalcontrol1.Theconnotation(内涵)ofGreenChemistry

Greenchemistryisanactiveintercrossingresearchareaintheworld,itdealswiththefrontierofchemicalresearch.

ThetraditionalwaysofenvironmentalprotectionjustbringusabouttemporarysolutionsforenvironmentalproblemswhileGreenChemistryprovidespermanentcures.GreenChemistryprovideswaystoreduceoreliminateenvironmentalpollutionfromthebeginning,whichcouldhaveeternalbenefits.TheprinciplesofGreenChemistrycouldandshouldbeusedtoalldomainofchemistryandchemicalengineering.Nopollutionshouldbeaccompaniedinchemicalprocesses,thisistosay,eliminatethepotentialofpollutionbeforeitoccurs.Therealizationofthisgoalmeansnoenvironmentalcontrolisneeded,becausetherewillbenopollution.TheGoalofGreenChemistry:GreenChemistryistheutilizationofasetofprinciplestoreduceoreliminatetheuseofhazardousmaterialsinthedesign,manufactureanduseofchemicals,andthesechemicals

themselvesshouldbeeconomicallyandenvironmentallybenign.

GreenChemistryistheapplicationofchemicalprinciples,chemicaltechnologiesandchemicalmethodstoreduceoreliminatetheuseofhazardousstartingmaterials,hazardousprocesses,hazardoustargetproducts,hazardousauxiliarysubstances(suchassolvents,separationagents)intheproductionanduseofchemicals.

GreenChemistryHazardousorpotentiallyhazardousprocessesshouldalsobereducedoreliminated.By-productsareexpectedtobeavoidedasthoroughlyaspossibleandthestartingmaterialsbeutilizedascompletelyaspossiblethussatisfyingasustainablecivilization.Environment&resourceSimultaneouslygiveoutGreenChemistrySolutionRecyclableeconomySustainabledevelopmentCrisesRequirementGreenChemistry2.GreenChemistryisrealizableThegoalofgreenchemistryistoseekforperfection(byovercomingdifficulties).Synthesisefficiencyishighlythoughtofingreenchemistry.GreenchemistrywayBringaboutatemporarysolutionTreattheexistedwasteTreatwasteProvideapermanentcureEliminatewastefromtheoriginNowasteproducedNotneedforwastetreatmentTraditionalwayWasteproducedFacingtheincreasingenvironmentalpollution3.GreenChemistryisdifferentfromenvironmentalcontrolWhy2.2PromotingthedevelopmentofGreenChemistry1.StronglydevelopgreenchemistrytosatisfythedemandforsustainabledevelopmentofhumansocietyTraditionalchemicalIndustryisaccompaniedbyunexpectedharmNootheralternativesexistGreenchemistryistheuniquesolution2.3AtomEconomyofChemicalReaction(化学反应的原子经济性)AtomutilizationAtomeconomyofchemicalreactionIncreasetheconversionofthereactants,theselectivityoftheproducts1.AtomutilizationTheconceptwasusedtoquantifythewaste(by-products)formedwhenacertainamountoftargetproductwasmanufacturedinachemicalreaction.RogerA.Sheldon1992Thetwomaincharacteristicsofchemicalreactionwith100%atomutilization:Thereactantscouldbefullyutilized,andtheresourcecouldbemostpossiblyusedeconomicallyThewastecouldbeminimized原子利用率=

目标产物的量按化学计量式所得所有产物的量之和

=目标产物的量各反应物的量之和╳

100%╳

100%Examples

Example1：Thepreparationofepoxy-ethane(环氧乙烷)fromethylene

Example2：Thepreparationofepoxy-propane(环氧丙烷)Example3：Thesynthesisofmethylacrylate(丙烯酸甲酯)Example1ThepreparationofepoxyethaneTraditionalwayCH2=CH2+Cl2+H2OClCH2CH2OH+HClClCH2CH2OH+Ca(OH)2+HClC2H4O+CaCl2+2H2OCH2=CH2+Cl2+Ca(OH)2

C2H4O+CaCl2+H2O7174441111844111+18=12944111+18+44╳

100%Atomutilization=4428+71+74╳

100%=25%=28Silvercatalyst

isusedtoconvertethylenedirectlytothetargetmoleculebyusingoxygenastheoxidant,whichgives100%atomutilization.NewgreenerwayCH2=CH2+1/2O2ashsska44C2H4O2816ashsska440ashsska4428+16=╳

100%╳

100%=44ashsska44=100%1.Highatomeconomy

(100%)2.Oxygen

is

safe

tohumanbeingsandtoenvironment.

3.Noseparationorpurification

isneeded.AdvantagesofthenewgreenermethodExample2Thepreparationofepoxy-propaneka4271587411118ashsskaashaashaasha58asha111+18=12958111+18+58╳

100%=5842+71+74╳

100%=31%

C3H6O+CaCl2+H2OCH3CH=CH2+Cl2+Ca(OH)2

=TraditionalwayDirectoxidationcatalyzedbytitania-silicaNewgreenerwayka42345818ashsskaashaasha

C3H6O+H2OCH3CH=CH2+H2O2

AshsskaTitania-sillicamolecularsieveashsska5818asha5858+18╳

100%=5842+34╳

100%=76%=aTheamountoftargetproductformedExample3Thepreparationofmethylacrylate(丙烯酸甲酯)

Thisprocessusestheby-productsfromphenol(苯酚)industryandacrylonitrile(丙烯腈):acetoneCH3COCH3andhydrocyanicacidHCN.TraditionalwayTraditionalwayCH3C(CN)(OH)CH3CH3COCH3+HCNAhsskaCH3OOC(CH3)C=CH2+NH4HSO4CH3OH,H2SO4CH3COCH3+HCN+CH3OH+H2SO4CH3OOC(CH3)C=CH2+NH4HSO4100+115╳

100%=58273298100115100115╳

100%10058+27+32+98100=46%Atomutilization=UsingpalladiumacetatePd(OAc)2asthecatalyst，developedin90’sNewgreenerwayPd(OAc)2

Theatomutilizationishigh

(100%)

Carbonmonoxideandmethanol

aresaferthanhydrocyanicacidtohumanbeingsandtoenvironment.

No

waste

producedAdvantagesofthe

newgreenermethod2AtomeconomyofchemicalreactionDefinition：TheratioofatomsappearedinthetargetmoleculestoalltheatomsofthereactantsThereactionwith100%atomutilizationisidealatomeconomicalreaction.

1991，BarryM.Trost1996,ThePresidentialGreenChemistryChallengeAwardofUSAHowtodesign

atomeconomicalreactions?DeficiencyofthetraditionalsyntheticwaysA+BC＋DwasteTargetmoleculeForatargetmoleculeC

Ifthetraditionalwayis

A+BC+D

Thisprocessinevitablyproducestheby-product

D,whichshouldbetreatedandcouldbeconsideredaswaste.Ifwewanttousethisreaction,wecouldnotavoidthisdilemma.AtomiceconomicreactionsE+FCTargetproductProblemThetypesoforganicreactions?Whichkindsareatomicallyeconomical?2.4.AtomEconomyandenvironmentaleffect

(原子经济性和环境效益)1.Environmentalfactor（环境因子）

Itisusedtoquantifytheeffectsofproductionprocesstotheenvironment

Idea:AllothercompoundsformedotherthanthetargetproductareconsideredtobeWASTE.RogerA.Sheldonin1992EnvironmentalfactorE=TheamountofwasteTheamountoftargetproductThelargerEThemorewasteformedThemoreseriousthepollutionIftheatomUtilization=100%E=0Theenvironmentalfactorofseveralindustries

Industries

Production/t

EPetrol106~108

~0.1FundamentalChemicals104~1061~5Finechemicals102~1045~50Pharmacy10~10325~100Buttheenvironmentalpollutionisstronglyassociatedwiththeharmfulperformanceofthewaste.2.Environmentalquotient(EQ，环境商)TheE

factorjustgivestheratioofthewasteandthetargetproduct.Environmentalquotient

E-----EnvironmentalfactorQ-----Theextentofhazardousnessofthewastetotheenvironmentobtainedfromtheperformanceofthewasteintheenvironment（根据废物在环境中的行为给出的废物对环境的不友好程度）.EQ＝E×Q2.5

ResearchmissionofgreenchemistryDesigningsaferandeffectivetargetmoleculesSeekingforsaferandeffective

startingmaterialsSeekingforsaferandeffective

syntheticprocessesSeekingfornewandsaferconversionwaysSeekingfornewand

safer

reactionconditionsItinvolvestwoaspects:Thedesigningofnewsafeandeffectivemolecules.2.

Thedesigningofnewsaferandeffectivemoleculestoreplacethemoleculeswhichexistedeffectivebutnotbenign2.

Seekingforsafer

andeffective

startingmaterials

⑴

Seekingnewstartingmaterialstosubstitutetheactuallyusedhazardousandpoisonousmaterials

Example1UsingCO2tosubstitutephosgene（光气）inthesynthesisofpolyurethane(聚氨酯)

Example2Eliminationtheuseofhydrocyanicacid（氢氰酸)

Example3Thesynthesisofadipicacid（己二酸）usingnewsafestartingmaterialsEliminatingthepoisonousphosgeneinthesynthesisofpolyurethaneandcarbonateExample1di-methylcarbonatePhosgeneiswidelyusedfortheproductionof

polyurethane:isocyanate(异氰酸酯)polyurethane(聚氨酯)Isocyanateisfirstsynthesizedbythereactionofphosgeneandamine,andthenusingisocyanatetoproducepolyurethane.TraditionalwayRNH2+COCl2

RNCO+2HCl

RNHCO2R1Thesynthesisofisocynate(异氰酸酯)RNCO+R1OHWhatkindsof

functionalgroup

would

phosgene

provideinachemicalreaction?

Whichkindofcompoundcouldbeemployedtosubstitutephosgene?providing-COgroupCarbondioxideisusedtosubstitutephosgeneintheproductionofisocyanate(providingcarbonylgroup)Thefunctionofphosgene:providing-COgroupRNH2+CO2RNCO+H2ORNHCO2R1NewgreenerwayRNCO+R1OHThesynthesisofisocyanateusingCO2C6H5NH2+CO2

C6H5N(H)CO2HC6H5N=C=O–H2OAniline2CH3OH+COCl2CH3OCOOCH3+2HCl2CH3OH+CO+½O2CH3OCOOCH3+H2OCatalystThesynthesisofdi-methylcarbonate碳酸二甲酯TraditionalwayNewgreenerwaysTheeliminationoftheuseofHCN(hydrocyanicacid,hydrogencyanide,prussicacid)bychangingtheprocess.Example2

Seriesofintermediatechemicalssuchaschelator/chelatingagent,ethionine(蛋氨酸)etc.HydrocyanicacidHCNiswidelyusedfortheproductionof:Seriesofmethylpropenoicacid(甲基丙烯酸系列).Hexanedinitrile(己二酸/己二腈);苯乙酸的合成Thesynthesisofsodiumiminodi-acetate(亚氨基二乙酸二钠)Traditionalwayinvolvestwosteps:NCCH2NHCH2CN

+2NaOH→NaO2CCH2NHCH2CO2Na+NH3NH3+2CH2O+2HCNNCCH2NHCH2CNAnewstartingmaterial----OCH2CH2NHCH2CH2OH

(diethanolamine,二乙醇胺)isused

NewgreenerwayThesynthesisofphenylaceticacid

C6H5CH2Cl+HCNC6H5CH2CN+HCl

C6H5CH2COOHH2OC6H5CH2Cl+COC6H5CH2COOHOH–/H2OTraditionalwayNewgreenerwayExample3Thesynthesisofadipicacidbychangingstartingmaterial

Thesynthesisofadipicacid(/hexanedioicacid己二酸)andhexamethylenediamine(己二胺)CH2=CHCH=CH2+HCNNCCH2CH2CH2CH2CNHOOC(CH2)4COOHH2N(CH2)6NH2Thehydrocarbonylationofbutadiene

CH2=CHCH=CH2+2CO+2H2OHC(CH2)4CHOHN=CH(CH2)4CH=NHH2N(CH2)6NH2HOOC(CH2)COOHO2catalyst2NH3-2H2O2H2Couldanyonetellmethe

disadvantagesofthesemethods?

PhotochemicalsmogDepletionofozone,AcidrainDisadvantagesofthe

traditionalmethods?ThestartingmaterialsishazardousThereleaseofnitrogenoxideswhicharemultifunctionalpollutantsUseofheavymetals(cobalt)Eliminationoftheuseofsolvent,theuseofhazardousbenzene,thecorrosivecapacityofhydrogenperoxideisnotassevereasnitricacid,nopollutantsproduced.KamzuhikoSato,1998,Science,281:1646-1647按照化学Newgreenermethod1Thesynthesismethodiswidened.DrathandFrost,

1990,1991Newgreenermethod2Notonlyeliminatetheuseofbenzene,butalsodevelopanewmethodtouserenewablebiomass(glucose).⑵Usingofrenewablestartingmaterial150yearsago,industrialorganicchemicalswereallderivedfrombiomassoriginatedfromplants.CoalOil+Naturalgas

StartingmaterialsBiomassIndustrialrevolutionSecurityandEnergyResourcesOil:30-50yearsNaturalGas:50-100yearsCoal:200-400yearsTheuseofbiomassasstartingmaterialforenergyandchemicalsproductionregainmuchattention,becauseofitsrenewability.

OnekindofsolarenergyItmustdegeneratebeforeitcouldbeeffectivelyused.Biomass：Starch(淀粉,amylum)+Lignin(木质素,lignine)Lignin：164billionts/yearamountused<1.5%Usingofrenewablestartingmaterialplants,trees,crops,grasses,aquaticplantsandtheirresiduesorwastematerials.MainFeasibleFormsofSolarEnergy

HydraulicEnergy:GreensolarenergyDepleting&RenewableFossilFuel:AccumulatedAncientSolarEnergy(Depleting)Biomass:RenewableAnimals&plants(convertedsolarenergy)FossilEnergyResourcesOilNaturalGasCoalAncientAnimalsandAncientPlantCarbonfixedbyancientlife-activitiesAncientSolarenergyBiomassResourcesBiomassCarbonFixedbyActualLife-activitiesIncludingAnimals&Plants

5hundredsmilliontonsofwheatstraw;10milliontonsofricebran;10milliontonsofcorncob;20milliontonsofricehull;7milliontonsofbiogases.Usingofrenewablestartingmaterialabout2.8～3.5hundredsmillion

oftonscanbeusedasresourceofenergy./yearInChinaTheburningofstraw:：wasteofresourcewhilepolluting

ThestructureofligninanditseffectonitsdegradationOrientateddegradationtoproducedirectlyusefulchemicalsHandlingandmanipulationofoxygen-richmoleculesTheeffectofimpuritiesonthedegenerationparametersanddistributionoftheproductsFundamentalscientificchallenge:Technicalchallenges

CollectionofbiomassVariationofcompositionsofdifferentkindsofbiomassandgrownfromdifferentareaoftheworldContinuousoperationHandlingofmixturesratherthanpurecompoundUpgradingandSeparationoftheproductsHowtouseeffectivelythebio-productsActualprogressesAgriculturalwaste(polysaccharides多糖)NaturallydegradablepolymerPekingUniversity,UniversityofScienceandTechnology,ShandongUniversity,ChemicalInstituteAcademyofChina,GuangzhouBiomassAnimalfeedsFuelChemicalsHaltzapplefromTexasA&Muniversity1996,ThepresidentialGreenChemistryAward

Convertingbiomasstofuelandchemicals

Directliquation

BiomassLiquidfuel&chemicals

Indirectconversion

GasificationC3-C4GasesGasfuelCO+H2Liquidfuel&chemicalsCatalyticconversionGasificationreactor(fixedbed)forbiomassconversiongasifierpurificationfangas

tankNeededByHomebiomass,airGasificationreactor(fluidizedbed)forbiomassconversiongasifierairbiomasstankCO+2H2=CH3OHmethanolCO,H2screwfeederashseparationcatalysisreationbedreformingreactionbedbiomassGasificationreactor(fluidized

bed)forbiomassconversionGasproduction：150M3/hOperationpressure：1MPaHeatcapacity：

7MJ/M3Efficiencyofenergyconversion：80%.Fast-growingbambooFast-growingshrubsConvertbiomasstousefulproducts

将生物质转化为化学化工原料开发新资源实现资源持续利用Agriculturalwaste3.Seekinganddesigning

saferandeffectivesyntheticroutes⑴

IdealsyntheticroutePaulAWender1996thestartingmaterialusedshouldbethecheapest

andmostfeasible;theoperationandmanipulationshouldbesimple,safeandenvironmentallybenign;thereactionrateshouldbefastandtheyieldofthetargetproductsshouldbeashighaspossible.

Thesyntheticrouteisaveryimportantfactortothebenignityofaprocess.Theintegrationofchemicalreactionstomakethewholeprocessbenign.⑵DesigningpropersyntheticrouteExample:

Thesynthesisofpara-phenylenediamine（对苯二胺,ursol）fromnitrobenzene(硝基苯,mirbaneoil)

Thesynthesisofpara-phenylenediaminefromnitrobenzeneLetusanalyzefourpossibleroutes

inagreenchemistryviewpointRoute1Theamountsofreactants:1062Targetmolecule:108Waste:954Atomutilization:Theoverallreaction

10%按照化学Route2Theoverallreaction

Theamountsofreactants:

300Targetmolecule:

108Waste:

192Atomutilization:36%按照化学Route3Theoverallreaction

Theamountsofreactants:543Targetmolecule:108Waste:435Atomutilization:20%按照化学Route4Theoverallreaction

Theamountsofreactants:162Targetmolecule:108Waste:54Atomutilization:67%Aggregativeanalysis

Fromtheviewpointofatomeconomy,route4isthemostfavorablecomparingtoothers。Inroutes1&2,becauseoftheprotectionof-NH2innitration,onemoleofaceticanhydrideisneededand2molesofaceticacidareformedaswaste,whileinroutes3&4,theprotectionstepwasnotneeded.

Practicalneed:

greatamountofpossibleroutes

foragivingtargetmolecule.

⑶

ComputeraideddesigningofsyntheticrouteCoreyandBersohn,30yearsagousedcomputertohelpdesigningofsyntheticroute30⇒30×30

⇒30×30×30

⇒……

⇒305>24millionroutese.g.Ifthesynthesisofacompoundneeds5steps,and30methodsarepossibleforeachstep,thuswewillhave

TheprogressofcomputationtechnologyItispossibleTheprogressincomputerscienceandtechnologyConstructionofadatabaseofchemicalreactionsascompleteaspossible.PutforwardourrequirementLetthecomputergiveusthepossiblestartingmaterialswhichcouldformthetargetmoleculeTechnicalWayFurthersearchforthestartingmaterialusingtheformerstartingmaterialasthetargetmolecules…………untiltheprovidedstartingmaterialisneededCompareallpossibleroutes,andchoosethemostfavorableonefromtheviewpointofeconomicalandenvironmentaleffect.4

Seekingfor

newconversionmethodsSeekingforunconventionalconversionways

☺Catalyticplasma☺Electrochemicalconversion☺PhotoandotherradiationconversionThesynthesisofgasolinefromcarbondioxideandmethaneCO2+CH42CO+2H2GasolineNickelcatalystFTprocessChangjunLiu,TianjingUniversityTraditionalthinkingupCO2+CH4GasolineCatalyst&plasmaconditionPlasma:breakingofthereactantmoleculesCatalyst:formingoftheproductmolecules☺

Catalyticplasma☺

UsingelectrochemicalwaysElectricitycanbeusednotonlyasanenergysupplyforchemicalreactions,itcouldalsoaffectchemicalreactionindifferentaspectsandprovidenewwaysforittooccur.Thefollowingexamplewillgiveussomedirectinformation.UsingelectrochemicalwaystoeliminatetheuseofhazardousstartingmaterialsandmakethereactiontooccuratmoderateconditionsCyclizationreactionTheelectro-synthesisofepoxypropaneUnfortunately,theselectivityofthisrouteisnotasgoodasexpected,andisnotyetindustrialized.AttheanodeH2O-NaClAtthecathodeThesynthesisofhexafluoropropyleneoxide六氟环氧丙烷F2CH=CFCF3PbO2/Steel/anodeSteel/cathodeH2O-HOAc-HNO3Theconversion:65-75%,Selectivity:90%ThisroutehasalreadybeenindustrializedbyHoechstCompany

CF3CFCF2OThesynthesisofpara-diphenylaminefromanilinebyelectrolysisC6H5NH2H2O-NH4I/PtNH3I-NH2NH2-NH24H++O2

+4eTheelectrosynthesisofpara-amino-phenol(PAP,对氨基苯酚)

Attheanode2H2OAtthecathodeC6H5NO2+4H++4e

+2H2OTheelectrosynthesisofhydroquinone(对苯二酚)AttheanodeC6H6+2H2O+6H+AtthecathodeC6H6+2H++2eThecycleopenreactionofdioxane(二恶烷)、O-orS-heterocyclohexane(氧硫杂环已烷)useheavymetalcatalysttraditionally,andadditionalreactantsareneeded.Eplingetcuselightasthereactingagenttorealizethesereactionandavoidthepollutioncausedbyheavymetals☺

Photoandotherradiationconversion5.

Seekingfor

Safeandeffectivereactionconditions⑴SeekingforsafeandeffectivecatalystLoadingofactivecomponentonsuitablesupportReplacingliquidacidsbysolidacids

Example1Example2

Loadingofactivecomponentson

suitablesupportTraditionalFriedel-Craftsreactions：

hydrofluoricacid(氢氟酸),sulfuricacid(硫酸),aluminiumchloride(三氯化铝),boronfluoride(三氟化硼,borontrifluoride)areusedasthecatalysts.Thedisadvantages:Theoperationmustbedoneanhydrously(waterfree),3molesofhydrogenchloridewillbereleasedwhenaccountingwater.Thesystemiscorrosive,strictoperationconditionsmustbecontrolled.

Lowselectivitybecauseoftheformationofpoly-alkyl-substitutedproductsandotherisomers.

Thedisadvantages:Inacylationreactions(酰基化)(ordinaryacylation,theformylationofbenzene,sulfo-acylation),largeamountofaluminiumchlorideisneededbecauesofthecomplexityoftheproducts.Finally,watermustbeaddedtoreleasetheproductmoleculeandthusreleasinglargeamountofhydrogenchlorideaswellaschlorinatedhydrocarbonsasimpurity.ThesupportedcatalystK10-AlCl3，preparedbysupportingAlCl3onmontmoriloniteshowsactivityashighastheconventionalonesandhigherselectivityfortheformationofmono-alkylatedproductthantheoldones.ThesupportingofZnCl2onmontmorilonitecouldalsoobtainanewkindofcatalystfortheFridel-Craftsreactions,andthisalreadyprovidesanewperspectiveforindustrialapplication.LoadingofactivecomponentsonsuitablesupportUsingsolidacidstoreplaceliquidacidsWhataretheadvantagesandofliquidacidscatalyst?HomogeneityDefinitelyknownstructurebecauseofsmallmoleculesEasilyinvestigationofthecatalyticmechanismMildreactionconditions

Lowtemperature:usuallybelow100℃SeparationofthecatalystfromthereactionmixtureCorrosivityandstrictoperationconditionsEnvironmentalpollutionWhatareDisadvantagesofliquidacidscatalyst?

Acidicclay,mixedchlorides,molecularsieveetc.couldbeusedtoreplaceliquidacids.Someinevitablebarriersthatcouldnotbeovercomeinhomogeneouscatalysiscouldbeloweredinacertaindegreeortotallyovercome.Thetemperaturerangecouldbewidenedto700-800K,andthuswideningtherangeofacidcatalysis.Example1:ThetraditionalFridel-Craftsacylationreaction:Targetproduct/Aluminiumchlorode,1/3

TheuseofnewcatalystEnvirocata.EPZGtoreplaceAlCl3,the