Qhov sib txawv tseem ceeb ntawm esterification thiab saponification yog tias esterification tsim ib qho ester whereas saponification tawg esters rau hauv nws cov khoom pib.
Ib ester yog tsim los ntawm carboxylic acid thiab cawv. Yog li, esterification yog tsim los ntawm ester los ntawm carboxylic acid thiab cawv. Thaum, saponification tsim cov carboxylic acid thiab cawv uas yog siv los tsim cov ester.
Esterification yog dab tsi?
Esterification yog tsim los ntawm ester los ntawm cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv. Cov txheej txheem no yuav tsum muaj lub catalyst txhawm rau txo qhov ua kom lub zog thaiv kev cuam tshuam ntawm cov tshuaj tiv thaiv. Qhov no catalyst feem ntau yog ib qho acid catalyst. Tsis tas li ntawd, cov tshuaj tiv thaiv sib tov yuav tsum tau ua kom sov vim tias cov txheej txheem esterification yuav tsum muaj zog (kom tshem tawm C-OH daim ntawv cog lus ntawm carboxylic acid kom tshem tawm -OH pawg).
Daim duab 1: Tsim ib qho Ester ntawm Esterification
txheej txheem Esterification suav nrog kev tshem tawm ntawm pawg hydroxyl (-OH) ntawm carboxylic acid thiab hydrogen atom ntawm pawg hydroxyl ntawm cawv. Thaum lub sijhawm txheej txheem no, thaum pawg -OH raug tshem tawm ntawm carboxylic acid, nws ua raws li electrophile. Thiab thaum lub proton ntawm cawv raug tshem tawm, nws ua raws li ib tug nucleophile. Yog li, qhov no nucleophile tawm tsam cov electrophile tsim los ntawm carboxylic acid, thiab tsim ib qho ester. Qhov no muab cov dej molecule ua ib qho khoom siv. Yog li, cov dej molecule tsim los ntawm kev sib xyaw ntawm -OH pawg los ntawm carboxylic acid thiab proton los ntawm cawv. Yog li, ib tus tuaj yeem tau txais cov ester ntshiab siv tus neeg ua kom lub cev qhuav dej (kom tshem tawm cov dej los ntawm cov tshuaj tiv thaiv sib tov).
Saponification yog dab tsi?
Saponification yog qhov tawg ntawm ester rau hauv carboxylic acid thiab cawv. Nws yog qhov opposite ntawm esterification. Saponification tshwm sim nyob rau hauv ib qho nruab nrab aqueous nyob rau hauv lub xub ntiag ntawm lub hauv paus. Cov xwm txheej hauv nruab nrab ua rau carboxylate anion ruaj khov dua li daim ntawv carboxylic acid. Yog li ntawd, carboxylate ion cais los ntawm ester. Saponification tuaj yeem tshwm sim thaum tsis muaj lub zog hluav taws xob vim nws tsis muaj lub zog thaiv. Ntawm no, cov dej molecules nyob rau hauv aqueous nruab nrab muab H+ ions, thiab lub hauv paus muab OH– ions xav tau rau kev tsim cov cawv thiab carboxylic acid. raws.
Daim duab 2: Cov txheej txheem dav dav ntawm saponification
Saponification cov tshuaj tiv thaiv mechanism:
- Nucleophilic nres
- Kev hloov kho
- Txoj kev tawm ntawm pawg
- Deprotonation
Cov hydroxyl ions (OH–) ua raws li nucleophiles vim lawv nplua nuj nrog electrons. Cov ions tuaj yeem tawm tsam ester daim ntawv cog lus (-C-O-O-) ntawm ester. Lawv tawm tsam cov pa roj carbon atom ntawm daim ntawv cog lus no vim tias cov pa roj carbon atom muaj cov nqi zoo ib nrab vim muaj cov pa oxygen atoms txuas rau carbon atom. Tom qab ntawd OH ion tsim ib daim ntawv cog lus nrog cov pa roj carbon atom. Tab sis cov pa roj carbon atom tsis tuaj yeem muaj tsib daim ntawv cog lus vim nws yog ib qho tsis ruaj khov ntawm cov pa roj carbon. Yog li ntawd, ib kauj ruam rearrangement yuav siv qhov chaw tom qab no daim ntawv cog lus. Nyob rau hauv cov kauj ruam rearrangement, cov molecules yuav ruaj khov los ntawm kev tshem tawm -OR pawg (uas yog los ntawm cov cawv uas tau siv los ua cov ester). Nws yog pawg tawm ntawm cov tshuaj tiv thaiv saponification. Lub deprotonation ntawm carboxylic acid tshwm sim vim hais tias cov carboxylate ion yog daim ntawv ruaj khov nyob rau hauv nruab nrab nruab nrab.
Qhov txawv ntawm Esterification thiab Saponification yog dab tsi?
Esterification vs Saponification |
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| Esterification yog tsim los ntawm ester los ntawm cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv. | Saponification yog qhov tawg ntawm ester rau hauv carboxylic acid thiab cawv. |
| Yuav tsum muaj zog | |
| Esterification xav tau lub zog hauv daim ntawv ntawm tshav kub. | Saponification tsis xav tau lub zog sab nraud. |
| Reactants | |
| Cov reactants ntawm esterification yog cawv thiab carboxylic acid. | Cov reactants ntawm saponification yog ester thiab puag nrog dej. |
| Catalyst | |
| Esterification xav tau cov kua qaub catalyst. | Saponification xav tau lub hauv paus catalyst. |
Summary – Esterification vs Saponification
Esterification thiab saponification yog cov tshuaj tiv thaiv tseem ceeb hauv chemistry. Esterification yog ester synthesis, thiab saponification yog tawg ntawm ester daim ntawv cog lus. Qhov sib txawv tseem ceeb ntawm esterification thiab saponification yog cov txheej txheem esterification cuam tshuam nrog kev tsim cov ester thaum cov txheej txheem saponification cuam tshuam nrog kev rhuav tshem cov ester rau hauv nws cov khoom pib.
