Qhov sib txawv tseem ceeb ntawm aldol condensation thiab Cannizzaro cov tshuaj tiv thaiv yog tias aldol condensation yog hom kev sib txuas cov tshuaj tiv thaiv, whereas Cannizzaro cov tshuaj tiv thaiv yog ib hom tshuaj tiv thaiv redox.
Nyob rau hauv cov tshuaj tiv thaiv aldol, ib qho enol lossis ib qho enolate ua ke nrog cov carbonyl compound los tsim β-hydroxyaldehyde lossis β-hydroxyketone. Peb hu nws ua kev sib txuas lus vim hais tias ob lub tebchaw ob peb los ua ib qho chaw loj. Ntawm qhov tod tes, Cannizzaro cov tshuaj tiv thaiv yog cov tshuaj tiv thaiv redox uas ib qho aldehyde molecule raug oxidation los tsim cov kua qaub thaum lwm qhov aldehyde txo qis los tsim cov cawv.
Aldol Condensation yog dab tsi?
Aldol condensation yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas yog β-hydroxyaldehyde los yog β-hydroxyketone yog tsim los ntawm kev sib xyaw ntawm ib qho enol lossis ib qho enolate nrog carbonyl compound. Yog li ntawd, peb tuaj yeem categorize nws raws li kev sib txuas lus. Cov tshuaj tiv thaiv yog ua raws li cov tshuaj tiv thaiv lub cev qhuav dej, uas muab ib qho conjugated enone. Cov tshuaj tiv thaiv dav dav yog raws li hauv qab no;
Mechanism
Muaj ob kauj ruam: aldol tshuaj tiv thaiv thiab lub cev qhuav dej. Qee zaum, muaj cov tshuaj tiv thaiv dicarboxylic, thiab. Lub cev qhuav dej ntawm cov khoom aldol tuaj yeem tshwm sim hauv ob txoj hauv kev: muaj zog hauv paus-catalyzed mechanism lossis acid-catalyzed mechanism. Lub tshuab ntawm aldol cov tshuaj tiv thaiv uas yog catalyzed los ntawm lub hauv paus yog raws li nram no:
Aldol condensation txheej txheem tseem ceeb heev hauv cov txheej txheem organic synthesis. Nws yog vim tias qhov tshuaj tiv thaiv no yog txoj hauv kev zoo los tsim cov pa roj carbon-carbon.
Cannizzaro Reaction yog dab tsi?
Cannizzaro cov tshuaj tiv thaiv yog cov tshuaj tiv thaiv cov organic redox uas muaj qhov tsis sib xws ntawm ob lub molecules tshwm sim los muab cov cawv thawj thiab carboxylic acid. Hauv cov tshuaj tiv thaiv no, qhov tsis sib xws yog cov tshuaj tiv thaiv hauv paus. Cov tshuaj tiv thaiv yog raws li nram no:
Ntawm no, qhov tshuaj tiv thaiv no cuam tshuam txog kev hloov pauv ntawm hydride los ntawm ib qho substrate mus rau lwm qhov. Tsis tas li ntawd, ib qho aldehyde compound undergoes oxidation, thiab lwm qhov yog txo qis. Oxidation ntawm aldehyde muab cov kua qaub thiab txo cov cawv.
Mechanism
Cov txheej txheem suav nrog nucleophilic acyl hloov pauv ntawm aldehyde compound. Ntawm no, cov pab pawg tawm concurrently tawm tsam lwm yam aldehyde. Thaum xav txog tag nrho cov tshuaj tiv thaiv, nws ua raws li kev txiav txim thib peb kinetics. Lub mechanism yog raws li nram no:
Qhov txawv ntawm Aldol Condensation thiab Cannizzaro Reaction yog dab tsi?
Aldol condensation yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas yog β-hydroxyaldehyde lossis β-hydroxyketone cov ntaub ntawv los ntawm kev sib xyaw ntawm ib qho enol lossis ib qho enolate nrog carbonyl compound. Nyob rau hauv sib piv, Cannizzaro cov tshuaj tiv thaiv yog ib qho organic redox cov tshuaj tiv thaiv nyob rau hauv uas ib tug disproportionation ntawm ob molecules tshwm sim los muab ib tug thawj cawv thiab carboxylic acid. Yog li, qhov sib txawv tseem ceeb ntawm aldol condensation thiab Cannizzaro cov tshuaj tiv thaiv yog tias aldol condensation yog ib hom kev sib txuas cov tshuaj tiv thaiv, thaum Cannizzaro cov tshuaj tiv thaiv yog hom tshuaj tiv thaiv kab mob.
Ntxiv mus, cov reactants ntawm aldol condensation yog ib qho enol lossis ib qho enolate thiab carbonyl compound thaum rau cov tshuaj tiv thaiv cannizzaro, cov reactants yog ob yam uas tsis yog-enolizable aldehydes. Cov khoom muab los ntawm aldol condensation yog β-hydroxyaldehyde los yog β-hydroxyketone, nyob ntawm seb hom carbonyl tebchaw uas muaj xws li cov reactant. Tab sis hauv Cannizzaro cov tshuaj tiv thaiv, cov khoom lag luam yog thawj cawv thiab carboxylic acid. Yog li, qhov no kuj yog qhov sib txawv ntawm aldol condensation thiab Cannizzaro cov tshuaj tiv thaiv.
Summary – Aldol Condensation vs Cannizzaro Reaction
Aldol condensation yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas yog β-hydroxyaldehyde lossis β-hydroxyketone cov ntaub ntawv los ntawm kev sib xyaw ntawm ib qho enol lossis ib qho enolate nrog carbonyl compound. Cov tshuaj tiv thaiv Cannizzaro yog ib qho organic redox cov tshuaj tiv thaiv nyob rau hauv uas ib tug disproportionation ntawm ob molecules tshwm sim los muab ib tug thawj cawv thiab ib tug carboxylic acid. Qhov sib txawv tseem ceeb ntawm aldol condensation thiab Cannizzaro cov tshuaj tiv thaiv yog tias aldol condensation yog ib hom kev sib txuas cov tshuaj tiv thaiv, thaum Cannizzaro cov tshuaj tiv thaiv yog ib hom tshuaj tiv thaiv redox.
