Cov Lus Nug Piv Txwv Sib Tham Txog Alkenes thiab Alkynes
Pendahuluuan
Hauv kev tshuaj lom neeg organic, alkenes thiab alkynes yog ob pawg tseem ceeb heev ntawm cov hydrocarbon compounds. Alkenes yog cov hydrocarbons unsaturated uas muaj ib lossis ntau carbon-carbon ob daim ntawv cog lus (C = C), thaum alkynes yog cov hydrocarbons unsaturated uas muaj ib lossis ntau carbon-carbon peb daim ntawv cog lus (C≡C). Kev nkag siab txog cov tshuaj tiv thaiv thiab cov txheej txheem ntawm ob hom tshuaj no yog qhov tseem ceeb rau ntau yam kev siv hauv chemistry.
Tsab xov xwm no yuav tshawb nrhiav qee qhov teeb meem piv txwv thiab kev sib tham txog alkenes thiab alkynes, uas tuaj yeem pab nkag siab txog cov ntsiab lus yooj yim thiab lawv daim ntawv thov hauv cov ntsiab lus xyaum.
Cov Lus Nug Piv Txwv thiab Kev Sib Tham Txog Alkenes
Lo lus nug thib 1:
Muab lub npe IUPAC rau cov tshuaj hauv qab no:
\[ \text{CH}_2=CH-\text{CH}_2-\text{CH}_3 \]
Kev Sib Tham:
1. Txheeb xyuas txoj saw ntev tshaj plaws uas muaj ob txoj hlua khi. Hauv qhov no, txoj saw ntev tshaj plaws yog butane (4 carbons).
2. Sau tus lej ntawm cov saw hlau los ntawm qhov kawg ze tshaj plaws rau qhov sib txuas ob npaug.
3. Txheeb xyuas qhov chaw ntawm cov khoom sib txuas ob npaug. Cov khoom sib txuas ob npaug yog nyob nruab nrab ntawm cov carbons 1 thiab 2.
4. Lub npe IUPAC ntawm cov tshuaj no yog 1-butene.
Lo lus nug thib 2:
Cov tshuaj 2-hexene dhau los ntawm kev sib ntxiv nrog Br₂ hauv CCl₄. Sau cov qauv sib xyaw thiab muab lub npe rau cov khoom tshwm sim.
Kev Sib Tham:
1. Qhov kev sib ntxiv ntawm Br₂ rau alkenes feem ntau tsim cov dibromoalkanes.
2. Cov qauv ntawm 2-hexene: CH₃-CH=CH-CH₂-CH₂-CH₃.
3. Ntxiv Br₂ rau hauv ob daim ntawv cog lus ua rau muaj 2,3-dibromohexane:
\[ \text{CH}_3-CH(\text{Br})-CH(\text{Br})-\text{CH}_2-\text{CH}_2-\text{CH}_3 \]
Cov Lus Nug Piv Txwv thiab Kev Sib Tham Txog Alkynes
Lo lus nug thib 3:
Muab lub npe IUPAC rau cov tshuaj hauv qab no:
\[ \text{CH}_3-\text{C}≡\text{C}-\text{CH}_3 \]
Kev Sib Tham:
1. Txheeb xyuas txoj saw ntev tshaj plaws uas muaj peb lub pob sib txuas. Txoj saw ntev tshaj plaws yog 4 lub carbons.
2. Sau tus lej ntawm cov saw hlau los ntawm qhov kawg ze tshaj plaws rau qhov sib txuas peb npaug.
3. Txheeb xyuas qhov chaw ntawm cov triple bond. Cov triple bond yog nyob nruab nrab ntawm cov carbons 2 thiab 3.
4. Lub npe IUPAC ntawm cov tshuaj no yog 2-butyne.
Lo lus nug thib 4:
Muab cov ntaub ntawv hais txog cov khoom uas tshwm sim los ntawm kev sib ntxiv ntawm HCl rau 1-butyne.
Kev Sib Tham:
1. Cov qauv ntawm 1-butyne: CH≡C-CH₂-CH₃.
2. Qhov ntxiv ntawm HCl ua rau muaj kev sib txuas peb npaug thiab tsim cov kev sib txuas ob npaug, ua rau muaj 2-chlorobut-1-ene.
3. Ntxiv HCl rau hauv ob daim ntawv cog lus ua rau cov khoom kawg: 2,2-dichlorobutane.
Cov txheej txheem tshuaj tiv thaiv
Lo lus nug thib 5:
Piav qhia txog cov txheej txheem ntawm alkene hydrohalogenation reaction nrog piv txwv reaction: propene nrog HBr.
Kev Sib Tham:
1. Theem 1: Protonation
– Cov kev sib txuas ob npaug ntawm propene (CH₂=CH-CH₃) cuam tshuam nrog proton (H⁺), tsim cov carbocation nruab nrab.
- H⁺ yuav ntxiv rau tus lej carbon ua rau muaj carbocation ruaj khov dua.
-Protonation ntawm C1 tsim cov carbocation theem nrab ruaj khov.
2. Kauj Ruam 2: Ntxiv Halide
– Bromide (Br⁻) yuav tawm tsam qhov carbocation, tsim 2-bromopropane:
\[ \text{CH}_{3}-\text{CH}_{{\text{Br}}}}-\text{CH}_2-\text{CH}_3 \]
Lo lus nug thib 6:
Piav qhia thiab piav qhia txog txoj hauv kev ntawm Br₂ ntxiv rau ethyne.
Kev Sib Tham:
1. Theem 1: Kev Tsim Cov Bromonium Ions
- Ethyne (CH≡CH) reacts nrog Br₂, los ntawm kev tsim cov bromonium ion nruab nrab.
\[ \text{CH}\equiv\text{CH} + \text{Br}_2 \rightarrow \text{BrCH=CHBr} \]
2. Theem 2: Kev Tsim Dibromoalkyne
- Cov bromonium ions raug tawm tsam tam sim ntawd los ntawm cov bromide ions dawb (Br⁻) los tsim dibromoalkynes.
- Qhov kev cuam tshuam tom qab ntawm bromination tsim 1,1,2,2-tetrabromoethane yog tias ua ntau dhau.
Kev Ua Haujlwm Oxidizing
Lo lus nug thib 7:
Txheeb xyuas cov khoom tsim tawm yog tias qhov tshuaj tiv thaiv ozonolysis raug ua tiav rau 2-pentene.
2. Qhov tshuaj tiv thaiv ozonolysis tsim ob daim carbonyl (ketone lossis aldehyde).
3. 2-pentene (CH₃-CH=CH-CH₂-CH₃) yog ozonolyzed los tsim butanone (CH₃-CO-CH₃) thiab formaldehyde (H-COH).
Cov Ntawv Thov Khoom Siv
Lo lus nug thib 8:
Kev tsim cov tshuaj but-2-yne los ntawm ethanol.
Kev Sib Tham
1. Hloov ethanol (CH₃-CH₂OH) mus rau ethene (CH₂=CH₂) los ntawm kev qhuav dej.
2. Ethene dhau los ntawm kev sib xyaw halogen los tsim 1,2-dibromoethane.
3. Kev tshem tawm cov pa roj carbon dioxide yog ua tiav los tsim cov voj voog ethyne.
4. kev nthuav dav ntxiv ua rau muaj 2-butyne.
Kev nkag siab txog cov tshuaj tiv thaiv no txhawb nqa kev daws teeb meem thiab kev xyaum ua hauv kev kawm tshwj xeeb txog organic chemistry.
