Qhov sib txawv tseem ceeb ntawm naphthenes thiab aromatics yog tias cov naphthenes tsuas muaj ib daim ntawv cog lus ntawm carbon atoms whereas aromatics muaj ob daim ntawv cog lus thiab ob daim ntawv cog lus ntawm carbon atoms.
Peb hu naphthenes "cycloalkanes". Cov no yog cyclic aliphatic hydrocarbon tebchaw. Peb tuaj yeem tau txais lawv los ntawm roj av. Cov qauv dav dav rau cov tebchaw no yog CnH2n Ntxiv mus, cov pa roj carbon atoms hauv cov nplhaib no yog saturated. Aromatics yog cyclic hydrocarbons muaj ib daim ntawv cog lus (sigma bonds) thiab ob daim ntawv cog lus (pi bonds) nyob rau hauv ib qho kev sib hloov. Yog li ntawd, peb tuaj yeem soj ntsuam delocalization ntawm electrons hauv cov tebchaw, thiab peb hu ua aromatics, "arenes".
Nafthenes yog dab tsi?
Naphthenes yog cyclic hydrocarbon tebchaw uas muaj cov qauv dav dav CnH2n Peb tuaj yeem tau txais cov khoom sib txuas ntawm cov roj av los ntawm kev ua kom zoo. Cov tebchaw no muaj ib lossis ntau lub nplhaib saturated. Qhov no txhais tau tias, tag nrho cov pa roj carbon atoms nyob rau hauv lub nplhaib sib koom ua ke ntawm ib leeg xwb (tsis muaj ob daim ntawv cog lus lossis triple daim ntawv cog lus tam sim no). Yog li ntawd, cov no yog qhov tseem ceeb alkanes. Yog li ntawd, peb hu lawv "cycloalkanes". Cov atoms uas tam sim no tsis yog carbon yog hydrogen atoms. Tab sis cov hydrogen atoms tsis tsim lub nplhaib; lawv tseem txuas nrog cov pa roj carbon atom hauv lub nplhaib. Raws li tus naj npawb ntawm cov pa roj carbon atoms hauv cov qauv no, peb tuaj yeem hu lawv li cyclopropane, cyclobutane, cyclopentane, cyclohexane, thiab lwm yam.
Daim duab 01: Cyclobutane
Txawm li cas los xij, yuav tsum muaj tsawg kawg peb carbon atoms los tsim ib lub voj voog, yog li tus tswv cuab tsawg tshaj plaws ntawm cov naphthenes yog cyclopropane. Peb hu ua cycloalkanes loj, muaj ntau tshaj 20 carbon atoms li "cycloparaffins". Txij li thaum thaj tsam ntawm lub nplhaib tso cai rau cov molecules no sib cuag nrog lwm tus, cov kev sib txuas ntawm lub zog (London rog) ntawm lawv muaj zog heev. Yog li ntawd, cov ntsiab lus kub kub, cov ntsiab lus melting, qhov ntom ntawm cov molecules yog siab dua li cov uas tsis yog-cyclic alkanes uas muaj tib cov pa roj carbon atoms. Yooj yim thiab loj naphthenes ruaj khov heev. Cov naphthenes me me muaj kev ruaj ntseg tsawg (vim lub nplhaib strain). Yog li, lawv yog reactive. Lawv tuaj yeem raug cov tshuaj tiv thaiv nucleophilic aliphatic hloov pauv.
Aromatic yog dab tsi?
Aromatics yog cyclic hydrocarbon tebchaw uas muaj conjugated planar nplhaib system nrog delocalized pi electron huab. Hauv lwm lo lus, cov qauv no muaj cov qauv sib hloov ntawm ib daim ntawv cog lus thiab ob daim ntawv cog lus ntawm cov pa roj carbon atoms uas tsim cov qauv nplhaib. Tsis muaj ib daim ntawv cog lus sib cais lossis ob daim ntawv cog lus. Peb hu lawv "arenes". Lub npe aromatic los ntawm qhov qab zib aroma ntawm cov tebchaw.
Daim duab 02: Qee Cov Aromatics
Aromatics tuaj yeem yog monocyclic lossis polycyclic. Qee lwm cov tebchaw uas peb hu ua "heteroarenes" kuj tau categorized li aromatics. Cov tebchaw no muaj cov atoms uas tsis yog carbon uas tsim lub nplhaib. Tab sis lawv yog cov aromatics vim lawv tsim ib qho kev sib txuas ntawm pi system thiab cov huab cua delocalized thiab.
Qhov txawv ntawm Naphthenes thiab Aromatics yog dab tsi?
Naphthenes yog cyclic hydrocarbon compounds uas muaj cov qauv dav dav CnH2n Cov molecules no tsuas muaj cov pa roj carbon atoms uas ua rau lub nplhaib. Tsis tas li ntawd, lawv tsuas muaj ib daim ntawv cog lus ntawm cov pa roj carbon atoms ntawm lub nplhaib. Aromatics yog cyclic hydrocarbon tebchaw uas muaj conjugated planar nplhaib system nrog delocalized pi electron huab. Cov molecules no yuav muaj lwm cov atoms xws li nitrogen nrog rau cov pa roj carbon uas ua rau lub nplhaib. Ntxiv mus, lawv muaj ob daim ntawv cog lus thiab ob daim ntawv cog lus ntawm cov pa roj carbon atoms hauv lub nplhaib raws li kev hloov pauv. Qhov no yog qhov txawv ntawm Naphthenes thiab Aromatics.
Summary – Naphthenes vs Aromatics
Naphthenes thiab aromatics yog ib qho tseem ceeb heev hydrocarbon tebchaw uas peb tuaj yeem tau txais los ntawm cov roj av. Qhov txawv ntawm naphthenes thiab aromatics yog tias cov naphthenes tsuas muaj ib daim ntawv cog lus ntawm carbon atoms whereas aromatics muaj ob qho tib si bonds thiab ob daim ntawv cog lus ntawm carbon atoms.
