天津大学有机化学双语PPT有机化学部分Chapter 2

2.1Classesofhydrocarbons2.2StructuresofAlkanes2.2.1StructuresofAlkanessp3HybridizedorbitalStructureofmetnaneStructureofethaneShapesofalkanes2.2.2IsomerizationofAlkanes2.3NomenclatureofAlkanes2.3.1UnbranchedAlkanes:,Chapter2Alkanes,2.3.2BranchedAlkanes2.3.3Branchedalkylgroups2.3.4CycloalkaneNomenclature2.4PropertiesofAlkanesandCycloalkanes2.5Conformation(构象)ofAlkanesandCycloalkanes2.5.1ConformationofAlkanes1.ConformationalAnalysisofEthane2.ConformationalAnalysisofButane2.5.2ConformationofCyclohexane1.Cis-transisomerisminCyclohexane2.ConformationofCyclohexane,3.ConformationalAnalysisofMono-substitutedCyclohenaxes4.ConformationalAnalysisofDisubstitutedcyclohexanes,Hydrocarbons(烃),C.Helements,Aliphatic(脂肪的),Aromatic(芳香的),Cycloalkanes,Alkenes,Alkynes,2.1ClassesofHydrocarbons,Alkanes,2.2StructuresofAlkanes,P35,1.15-1.16,2.2.1StructuresofAlkanes,C:,1s22s22px12py12pz0,Electronicconfigurationingroundstateofacarbonatom,Hybridorbitals(杂化轨道):,Groundstate,Promotionofelectron,Exitedstate,sp3-Hybridizedstate,Hybri-dized,Ansp3orbital,sorbitalporbital,4tetrahedralsp3orbitals,Geometricstructure:tetrahedron,109.5,Fourtetrahedralsp3orbital,TheStructureofMethane,4equivalentC键,Bondangle:109.5,C:sp3orbitalH:1sorbital,Geometricstructure:tetrahedron,Aball-and-stickmodelofmethane,Aspaceandfillingmodelofmethane,TheStructureofethane,P14,1.8,C2H6,CH3CH3,Thecarbon-carbonbondisformedbyoverlapof2carbonsp3hybridorbitals.,Thecharacterofbond:Higherbondenergy;Lowerpolarizability；Rotationaboutbondaxes.,Anball-and-stickmodelofethane(球棒模型),Shapesofalkanes,Zigzagnotstraight（曲折性）,2.2.2IsomerizationofAlkanes,P41,2.2,BeginningwithC4H10,n-Pentane,Straight-chain,unbranchedalkanesornormalalkanes,Isopentane,Neopentane,Branched-chainalkane,Generalformule:CnH2n+2,ConstitutionalIsomers(构造异构体),2.3NomenclatureofAlkanes,P44,Commonnomenclature,Isohexane,IUPACNomenclature:,2.3.1UnbranchedAlkanes:,2.3.2BranchedAlkanes,Step1Findtheparenthydrocarbon,Findthelongestcontinuouschainofcarbonatoms,P47,2.3,Toequallongchains,choosethechaincontainingthemostbranchedchain.,Heptane(庚烷),Step2Numbertheatomsinthemainchain.,Beginningattheendnearerthefirstbranchpoint,numbereachCatomintheparentchain.,(I),(II),3.Designatethelocationofthesubstituents,5-丙基-4-异丙基壬烷,4-Isopropyl-5-propylnonane,Listthesubstituentsinalphabeticalorder.,Whenthesamesubstituentsappearsmorethanonce,usethemultiplyingprefixes:di-,tri-,tetra-andsoon(一，二，三，四).,2,2,4-Trimethylpentane,2,2,4-三甲基戊烷,Isooctane(异辛烷),4-Ethyl-3,5-dimethyloctane,3,5-二甲基-4-乙基辛烷,Replicatingprefixesareignoredwhenalphabeizing.,2.3.3Branchedalkylgroups,Primarycarbon(伯碳),Secondarycarbon(仲碳),AlkylgroupsName,3-tert-Butylhexane,(3-叔丁基己烷）,2.3.4CycloalkaneNomenclature,1,1-二甲基-3-异丙基环戊烷,3-Isopropyl-1,1-dimethylcyclopentane,2.4PropertiesofAlkanesandCycloalkanes,P50,2.4,SourceofAlkanesandCycloalkanes:,Naturegas:,Metane,ethaneandpropane.,Petroleum:150hydrocarbons.,Kerosene,gasoil.,Lubricatingoil,paraffinwax,asphalt.,Alkanesshowregularincreasesinbothboilingpointandmeltingpointasmole-cularweightincreases.,Vanderwaalsforces(范德华力）,Branchedalkaneshavelowerboilingpointsthantheirunbranchedisomers.,2.5Conformation(构象)ofAlkanesandCycloalkanes2.5.1ConformationofAlkanes,Foralkanes:,Ex.,Conformation:,DifferentspatialarrangementsofatomsoratomicgroupsinamoleculethataregeneratedbyrotationaboutCCsinglebond.,1.ConformationalAnalysisofEthane,NewmanProjection(纽曼投影式),Sawhorse(锯架式),NewmanProjection(纽曼投影式):,Energy:EclipsedStaggered,Torsionalstrain,Interconversion,Relationbetweenconformations:Conformers(构象异构体)orRotamers,2.ConformationalAnalysisofButane,RotationaboutC2C3bondinbutane,Ch.23(4),2.5.2ConformationofCyclohexane1.Cis-transisomerisminCyclohexane,Ex.1,2-Dimethylcyclopentane:,Therotationislimitedby“rigid”ring,Stereoisomers:,RotationfreedomaroundCCbondinopen-chainalkanes.,P58,2.8,Thestructureofcyclohexaneisnonplanar:,Chairconformation（椅式构象）,Boatconformation（船式构象）,2.ConformationofCyclohexane,P62,Ch.138,Bothconformationsareinterconverted:,Butthechairconformationismorestablethanboat.,Inchairconformation,allCHbondsarestaggered;butinboatconformation,allCHbondsareeclipsed.,Inchairconformation,C1,C3,C5areco-planar;C2,C4,C6areco-planar.,TwokindsofCHbonds:6CHbondsareaxials;6CHbondsareequatorials.,P63,2.10,Onechairconformationisconvertedtoanotherchair:,Astheresultofringinversion,anyaxialbondbecomesequatorialandviceversa.,P65,2.11,Conformationalmobilityofcyclohexane,Chair-chairinterconversion:,Energy:,ChairTwistboatBoatHalf-chair,Thedirectionalpropertiesofthebondstotheringcarbons:,Ontheadjacentpositions:thesamebonds(a,aore,e)areopposites;thedifferentbonds(a,e)areidenticals.,OnthepositionseparatedbyoneCatom:thesamebonds(a,aore,e)areidenticals;thedifferentbonds(a,e)areopposites.,Onthe1,4position:,?,ConformationalAnalysisofmono-substitutedCyclohexanes,Inmethylcyclohexane:,Vanderwaalsstrain,1,3-diaxialrepulsion,Methylgroup:Fromaxialtoequatorial,5%,95%,veryfast,0.01%,99.99%,Asthegroupislarger,theconformationofcyclohexanewiththegroupequatorialismorestablethantheaxialform.,4.ConformationalAnalysisofDisubstitutedcyclohexanes,Wedge-and-dashdescription(伞式):,cis-1,4-Dimethylcyclohexane顺-1,4-二甲基环己烷,trans-反-,Thetrans-formismorestable,cis-Form:,(a,e),(e,a),trans-Form:,Thegeneralrule:Theconformationwithequatorialsubstituentismorestablethanaxialform.,b.Theconformationwiththelargersubstituentinequatorialpositionismorestablethantheaxialform.,c.Toapolysubstitutedcyclohexane,themoresubstituentsareinequatorialbonds,thestableisitsconformation.,cis-1-Methyl-4-tert-butyl-Cycloh