Qhov sib txawv tseem ceeb ntawm alkenes thiab alkynes yog tias cov alkenes muaj carbon-carbon ob daim ntawv cog lus thaum lub alkynes muaj carbon-carbon triple bonds.
Ob leeg alkenes thiab alkynes yog hydrocarbons muaj carbon thiab hydrogen atoms. Nws tuaj yeem muaj lwm yam hloov pauv txuas rau cov molecules no tsis yog hydrogens. Yog li ntawd, muaj coob tus molecules yog ua tau. Vim muaj ntau daim ntawv cog lus, lawv tuaj yeem polymerize thiab ua cov saw loj. Yog li, lawv muaj txiaj ntsig tshwj xeeb hauv kev siv cov khoom siv polymer. Piv txwv li, PVC, roj hmab, ntau yam yas, thiab lwm yam.
Alkenes yog dab tsi?
Alkenes yog hydrocarbons nrog carbon-carbon ob daim ntawv cog lus. Peb hu lawv ua olefins thiab. Ethene yog qhov yooj yim tshaj plaws alkene molecule, muaj ob carbons thiab plaub hydrogens. Nws muaj ib tug carbon-carbon ob daim ntawv cog lus, thiab cov qauv molecular yog C 2 H 4 Cov qauv tshuaj ntawm cov molecule no yog raws li nram no:
H2C = CH2
Thaum lub npe alkenes, peb siv cov lus "ene" hloov "ane" tom kawg ntawm lub npe ntawm alkane. Peb yuav tsum coj cov saw hlau ntev tshaj plaws uas muaj ob daim ntawv cog lus thiab yuav tsum suav nws hauv ib txoj kev, muab tus lej tsawg kawg rau ob daim ntawv cog lus. Lub cev lub cev ntawm alkenes zoo ib yam li cov alkanes sib raug.
Nature
Feem ntau, cov alkenes uas tsis tshua muaj molecular hnyav yog nyob rau hauv daim ntawv gaseous ntawm chav tsev kub. Piv txwv li, ethane thiab propene yog gases. Alkenes yog cov tsis-polar molecules; Yog li ntawd, lawv yaj nyob rau hauv nonpolar cov kuab tshuaj los yog cov kuab tshuaj uas muaj polarity tsawg heev. Yog li, alkenes me ntsis soluble hauv dej. Ntxiv mus, qhov ceev ntawm alkenes tsawg dua dej.
Cov tebchaw no tau txais kev cuam tshuam ntxiv vim yog ob daim ntawv cog lus. Piv txwv li, nyob rau hauv cov tshuaj tiv thaiv hydrogenation, ob lub hydrogens txuas rau ob daim ntawv cog lus thiab ua rau cov alkene rau cov sib thooj alkane. Cov tshuaj tiv thaiv no nrawm dua nyob rau hauv muaj cov hlau catalyst. Nyob rau hauv ib qho ntxiv cov tshuaj tiv thaiv zoo li no, yog tias cov reagent uas yuav txuas mus rau ob daim ntawv cog lus txuas mus rau tib sab ntawm cov molecule, peb hu nws ua qhov sib ntxiv. Yog hais tias qhov sib ntxiv yog nyob rau sab nraud, ces peb hu nws anti add.
Daim duab 01: Kev sib piv ntawm Alkanes, Alkenes thiab Alkynes
Ib yam li ntawd, alkenes tau txais ntau hom kev ntxiv nrog cov molecules xws li halogens, HCl, dej thiab lwm yam. Cov khoom ntxiv tuaj yeem tshwm sim raws li Markonikov lossis anti- Markonikov hom. Ntxiv mus, peb tuaj yeem ua cov molecules ntawm kev tshem tawm cov tshuaj tiv thaiv. Thaum xav txog kev ruaj ntseg ntawm alkenes, qhov ntau hloov cov pa roj carbon atoms ntawm ob daim ntawv cog lus, qhov ntau dua yog qhov ruaj khov. Tsis tas li ntawd, alkenes yuav muaj diastereoisomers; yog li ntawd, tuaj yeem qhia stereoisomerism.
Alkynes yog dab tsi?
Hydrocarbon molecules nrog carbon-carbon triple daim ntawv cog lus yog alkynes. Lub npe nrov rau tsev neeg no yog acetylenes. Ethylene yog qhov yooj yim molecule hauv tsev neeg no nrog ob carbons thiab ob hydrogens. Nws muaj cov qauv molecular ntawm C2H2 thiab hauv qab no yog nws cov qauv.
H - C ≡ C - H
Peb tuaj yeem muab cov npe no ua ntau yam zoo ib yam li alkenes. Qhov ntawd yog, peb tuaj yeem muab lawv lub npe los ntawm kev hloov lub "ane" nrog "yne" tom kawg ntawm lub npe ntawm cov sib thooj alkane. Nyob ntawd, peb yuav tsum suav cov saw hlau ntawm carbons kom muab cov pa roj carbon atoms ntawm triple daim ntawv cog lus tus lej qis tshaj plaws.
Daim duab 02: Piv txwv rau Alkynes
Tsis tas li ntawd, lub cev lub cev ntawm alkynes zoo ib yam li cov alkanes sib raug. Feem ntau, cov alkynes uas tsis tshua muaj molecular hnyav yog nyob rau hauv daim ntawv gaseous ntawm chav tsev kub. Piv txwv li, ethylene yog ib qho roj. Ntxiv mus, cov tebchaw no yog cov tsis-polar molecules; Yog li ntawd, lawv yaj nyob rau hauv nonpolar cov kuab tshuaj los yog cov kuab tshuaj uas muaj polarity tsawg heev. Yog li ntawd lawv yog me ntsis soluble nyob rau hauv dej. Qhov ntom ntawm alkynes tsawg dua dej. Alkynes tau txais cov tshuaj tiv thaiv ntxiv, vim nws txoj kev cog lus triple. Tsis tas li ntawd, peb tuaj yeem ua ke lawv los ntawm kev tshem tawm cov tshuaj tiv thaiv.
Qhov txawv ntawm Alkenes thiab Alkynes yog dab tsi?
Alkenes thiab alkynes yog unsaturated hydrocarbons. Qhov sib txawv tseem ceeb ntawm alkenes thiab alkynes yog tias cov alkenes muaj carbon-carbon ob daim ntawv cog lus thaum alkynes muaj carbon-carbon triple bonds. Ntxiv mus, ob daim ntawv cog lus carbons yog sp 2 hybridized hauv alkenes, thiab triple bonds yog sp hybridized hauv alkynes. Qhov sib txawv ntxiv ntawm alkenes thiab alkynes yog tias cov alkenes tsis muaj acidic hydrogen thaum alkynes muaj acidic hydrogen atoms.
Cov hauv qab no yog cov duab sawv cev ntawm qhov sib txawv ntawm alkenes thiab alkynes.
Summary – Alkenes vs Alkynes
Alkenes thiab alkynes yog hydrocarbon compound uas muaj carbon atoms hydrogen atoms. Tsis tas li ntawd, lawv yog cov sib txuas tsis txaus ntseeg (muaj ob lossis peb daim ntawv cog lus). Qhov sib txawv tseem ceeb ntawm alkenes thiab alkynes yog tias cov alkenes muaj carbon-carbon ob daim ntawv cog lus thaum lub alkynes muaj carbon-carbon triple bonds.
