Qhov sib txawv tseem ceeb ntawm Friedel Crafts acylation thiab alkylation yog tias Friedel Crafts Acylation koom nrog acylation ntawm ib lub nplhaib aromatic whereas Friedel Crafts Alkylation koom nrog alkylation ntawm ib lub nplhaib aromatic. Tsis tas li ntawd, ntau qhov kev cuam tshuam thiab carbocation rearrangements tsis tshwm sim hauv acylation cov tshuaj tiv thaiv thaum lawv tuaj yeem tshwm sim hauv cov tshuaj tiv thaiv alkylation.
Friedel Crafts cov tshuaj tiv thaiv yog ib txheej ntawm cov tshuaj tiv thaiv uas peb tuaj yeem siv los txuas cov pab pawg hloov mus rau cov nplhaib uas muaj ntxhiab thiab tshem tawm cov pab pawg hloov ntawm cov nplhaib uas muaj ntxhiab. Cov kws tshawb fawb Charles Friedel thiab James Crafts tau tsim cov kev cuam tshuam no hauv xyoo 1877. Muaj ob lub ntsiab ntawm cov tshuaj tiv thaiv no, thiab lawv yog Friedel Crafts acylation cov tshuaj tiv thaiv thiab Friedel Crafts alkylation cov tshuaj tiv thaiv. Ob qho no yog cov tshuaj tiv thaiv electrophilic.
Friedel Crafts Acylation yog dab tsi?
Friedel Crafts acylation koom nrog kev txuas ntawm pawg acyl rau lub nplhaib uas muaj ntxhiab. Qhov sib ntxiv ntawm pawg acyl no yog "acylation" hauv cov organic chemistry. Cov tshuaj acylating ib txwm siv rau cov tshuaj tiv thaiv no yog acyl chlorides. Tsis tas li ntawd, cov catalysts txhim kho qhov kev loj hlob ntawm cov tshuaj tiv thaiv no. Cov catalysts muaj xws li acids thiab txhuas trichloride.
Daim duab 01: Benzene Friedel Crafts Acylation
Ntxiv mus, peb tuaj yeem ua qhov tshuaj tiv thaiv no siv cov kua qaub anhydrides. Muaj qhov zoo ntawm cov tshuaj tiv thaiv no tshaj alkylation. Ib qho yog, ntau acylations tsis tshwm sim tib lub sijhawm. Nws yog vim hais tias cov khoom ketone ntawm cov tshuaj tiv thaiv yog ib txwm tsis tshua muaj reactive tshaj qhov qub molecule vim yog electron rho tawm cov nyhuv ntawm pawg carbonyl. Ntxiv mus, tsis muaj carbocation rearrangements thaum lub sij hawm kev loj hlob ntawm cov tshuaj tiv thaiv. Cov carbonium ion uas tsim thaum lub sij hawm cov tshuaj tiv thaiv stabilizes los ntawm resonance qauv.
Friedel Crafts Alkylation yog dab tsi?
Friedel Crafts alkylation cuam tshuam nrog kev sib txuas ntawm pawg alkyl rau lub nplhaib uas muaj ntxhiab. Nws yog ib qho tshuaj tiv thaiv electrophilic. Peb tuaj yeem siv alkyl halides rau cov tshuaj tiv thaiv no nrog rau lub zog Lewis acid catalyst. Yog tias peb siv ferric chloride (FeCl 3) ua cov catalyst, nws txuas rau chloride ion ntawm alkyl chloride thiab tsim cov alkyl cation. Qhov no alkyl cation tuaj yeem txuas mus rau lub nplhaib uas muaj ntxhiab. Qhov loj tsis zoo ntawm cov tshuaj tiv thaiv no yog tias cov khoom ntawm cov tshuaj tiv thaiv yog ntau nucleophilic dua li cov reactant. Yog li ntawd, qhov no yuav ua rau overalkylation.
Daim duab 02: Benzene Friedel Crafts Alkylation
Ntxiv mus, cov tshuaj tiv thaiv yog tsim rau tertiary carbon nyob rau hauv lub nplhaib aromatic. Txwv tsis pub, carbocation yuav raug kho dua tshiab. Muaj qhov kev xav tias Friedel Crafts alkylation cov tshuaj tiv thaiv yog thim rov qab. Peb hu nws Friedel Crafts de-alkylation.
Qhov txawv ntawm Friedel Crafts Acylation thiab Alkylation yog dab tsi?
Friedel Crafts Acylation koom nrog kev txuas ntawm pawg acyl rau lub nplhaib uas muaj ntxhiab. Tsis muaj ntau yam tshuaj tiv thaiv acylation vim tias cov khoom ketone ntawm cov tshuaj tiv thaiv ib txwm tsis tshua muaj tshwm sim dua li cov qauv qub vim yog cov nyhuv electron rho tawm ntawm pawg carbonyl. Ntxiv mus, tsis muaj carbocation rearrangements. Hauv qhov sib piv, ntau qhov kev tawm tsam alkylation tshwm sim thaum lub sij hawm Friedel Crafts alkylation uas cuam tshuam nrog cov pab pawg alkyl rau lub nplhaib uas muaj ntxhiab. Yog tias qhov kev hloov pauv tshwm sim ntawm cov pa roj carbon monoxide thawj lossis theem nrab, muaj cov carbocation rearrangements ib yam nkaus.
Summary – Friedel Crafts Acylation vs Alkylation
Friedel Crafts cov tshuaj tiv thaiv yog ib txheej ntawm cov tshuaj tiv thaiv organic uas cuam tshuam nrog acylation thiab alkylation cov tshuaj tiv thaiv. Qhov txawv ntawm Friedel Crafts acylation thiab alkylation yog tias Friedel Crafts acylation cov tshuaj tiv thaiv cuam tshuam nrog acylation ntawm ib lub nplhaib aromatic whereas Friedel Crafts alkylation koom nrog alkylation ntawm ib lub nplhaib aromatic.
