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1、新编化学化工专业英语翻译Lesson2OrganicChemistryThenatureofOrganicChemistryhaschangedgreatlysince1828.Beforethattimethescientificphilosophyknownas“Vitalism”maintainedthatOrganicChemistrywasthechemistryoflivingsystems.Itmaintainedthatorganiccompoundscouldonlybeproduced
2、withinlivingmatterwhileinorganiccompoundsweresynthesizedfromnon-livingmatter.Eventheword“organic”comesfromthesamerootastheword“organism”or“organ”.HoweverpeoplelikeProfessorWohlerbeginningin1828determinedthatitwasindeedpossibletosynthesizeorganiccompoundsf
3、romthosecompoundsthatwereconsideredinorganic.OneofthefirstorganiccompoundssynthesizedfrombasicallyinorganiccompoundswasthecompoundUreawhichisametabolicproductofurine.ItwassynthesizedfromAmmoniumCyanateconsideredacompoundproducedoutsideoflivingmatterandthe
4、reforeconsideredinorganic.SincethenmanymillionsofOrganiccompoundshavebeensynthesized“invitro”inotherwordsoutsidelivingtissue.1StructuralformulasThebuildingblockofstructuralorganicchemistryisthetetravalentcarbonatom.Withfewexceptions,carboncompoundscanbefo
5、rmulatedwithfourcovalentbondstoeachcarbon,regardlessofwhetherthecombinationiswithcarbonorsomeotherelement.Thetwo-electronbond,whichisillustratedbythecarbon-hydrogenbondsinmethaneorethaneandthecarbon-carbonbondinethane,iscalledasinglebond.Intheseandmanyrel
6、atedsubstances,eachcarbonisattachedtofourotheratoms:Thereexist,however,compoundssuchasethene(ethylene),C2H4,inwhichtwoelectronsfromeachofthecarbonatomsaremutuallyshared,therebyproducingtwotwo-electronbonds,anarrangementwhichiscalledadoublebond.Eachcarboni
7、netheneisattachedtoonlythreeotheratoms:Similarly,inethyne(acetylene),C2H2,threeelectronsfromeachcarbonatomaremutuallyshared,producingthreetwo-electronbonds,calledatriplebond,inwhicheachcarbonisattachedtoonlytwootheratoms:Byconvention,asinglestraightlineco
8、nnectingtheatomicsymbolsisusedtorepresentasingle(two-electron)bond,twosuchlinestorepresentadouble(four-electron)bond,andthreelinesatriple(six-electron)bond.Representationsofcompoundsbythesesymbolsarecalledstructural