Qhov sib txawv tseem ceeb ntawm Fischer esterification thiab Steglich esterification yog Fischer esterification cuam tshuam cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv nyob rau hauv muaj cov kua qaub uas muaj zog li catalyst whereas Steglich esterification cuam tshuam cov tshuaj tiv thaiv ntawm carboxylic acid thiab ib qho cawv nyob rau hauv lub xub ntiag ntawm dimethylaminopyridine (DMAP) raws li ib tug catalyst.
Esterification yog ib qho tseem ceeb organic synthesis cov tshuaj tiv thaiv hauv chemistry uas peb tuaj yeem tsim cov ester compound siv carboxylic acid thiab cawv. Cov tshuaj tiv thaiv no, txawm li cas los xij, yuav tsum muaj lub catalyst los txhawb cov tshuaj tiv thaiv. Fischer esterification thiab Steglich esterification yog ob hom esterification cov tshuaj tiv thaiv uas peb tuaj yeem siv ob hom catalysts uas tshwj xeeb rau txhua qhov tshuaj tiv thaiv.
Fischer Esterification yog dab tsi?
Fischer esterification yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas peb tuaj yeem tsim cov ester los ntawm cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv nyob rau hauv muaj cov kua qaub uas muaj zog ua cov catalyst. Nws yog ib hom tshwj xeeb ntawm cov tshuaj tiv thaiv esterification uas refluxing ntawm carboxylic acid thiab cawv tshwm sim los muab cov khoom kawg. Txoj kev no tau tsim los ntawm Emil Fischer hauv xyoo 1895. Yuav luag tag nrho cov carboxylic acid tebchaw tsim nyog rau cov tshuaj tiv thaiv no, tab sis tsuas yog cov cawv thawj thiab theem nrab siv tau. Thaum siv cov cawv tertiary, nws tuaj yeem ua rau tshem tawm cov tshuaj tiv thaiv tsis yog esterification. Feem ntau siv catalyst rau cov tshuaj tiv thaiv no yog sulfuric acid; Txawm li cas los xij, muaj qee cov catalysts zoo li, xws li p-toluenesulfonic acid thiab Lewis acids.
Daim duab 01: Ib qho cuab yeej siv rau Fisher Esterification
Lub Fischer esterification yog tsim rau cov khoom muaj nqis tsawg dua thiab tsis tshua muaj siab. Thaum xav txog cov tshuaj tiv thaiv esterification uas koom nrog hauv txoj kev no, peb feem ntau siv qhov nruab nrab uas tsis muaj qhov hnyav, feem ntau yog siv cov cawv ntau dhau. Los yog lwm yam, txoj kev yog nqa tawm siv cov kuab tshuaj tsis muaj polar xws li toluene. Hom kuab tshuaj no pab txhawb txoj kev Dean-Stark (ib qho txheej txheem tseem ceeb uas pab khaws cov dej uas tsim los ntawm cov khoom siv esterification).
Steglich Esterification yog dab tsi?
Steglich esterification yog ib hom tshuaj lom neeg cov tshuaj tiv thaiv uas peb tuaj yeem tsim cov ester los ntawm cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv nyob rau hauv lub xub ntiag ntawm dimethylaminopyridine (DMAP) raws li ib tug catalyst thiab dicyclohexylcarbodimide (DCC) raws li ib tug coupling. tus neeg sawv cev. Txoj kev tshuaj tiv thaiv no tau tsim los ntawm tus kws tshawb fawb Wolfgang Steglich hauv xyoo 1978.
Daim duab 02: Cov qauv dav dav rau Stiglich Esterification
Feem ntau, qhov tshuaj tiv thaiv no tshwm sim ntawm chav tsev kub. Cov kuab tshuaj zoo tshaj plaws rau txoj kev no yog dichloromethane. Cov tshuaj tiv thaiv no yog mos heev, yog li peb tuaj yeem tau txais esters uas tsis tuaj yeem siv tau los ntawm lwm txoj kev. Raws li cov yam ntxwv tshwj xeeb, peb tuaj yeem soj ntsuam (cov dej tsim hauv txoj kev no) uptake los ntawm DCC. Cov dej no tsim cov urea compound, dicyclohexylurea (DCU).
Qhov txawv ntawm Fischer Esterification thiab Steglich Esterification yog dab tsi?
Esterification yog cov tshuaj lom neeg cov tshuaj tiv thaiv uas muaj txiaj ntsig zoo hauv kev tsim cov ester. Qhov sib txawv tseem ceeb ntawm Fischer esterification thiab Steglich esterification yog tias Fischer esterification cuam tshuam cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv nyob rau hauv lub xub ntiag ntawm ib tug muaj zog acid raws li lub catalyst whereas Steglich esterification cuam tshuam cov tshuaj tiv thaiv ntawm ib tug carboxylic acid thiab ib tug cawv nyob rau hauv muaj. Dimethylaminopyridine (DMAP) ua ib qho catalyst.
Hauv qab infographic tabulates ntau qhov sib txawv ntawm Fischer esterification thiab Steglich esterification.
Summary – Fischer Esterification vs Steglich Esterification
Fischer esterification thiab Steglich esterification yog ob hom esterification cov tshuaj tiv thaiv uas sib txawv ntawm ib leeg raws li cov catalyst siv hauv cov tshuaj tiv thaiv. Qhov sib txawv tseem ceeb ntawm Fischer esterification thiab Steglich esterification yog tias Fischer esterification cuam tshuam cov tshuaj tiv thaiv ntawm carboxylic acid thiab cawv nyob rau hauv lub xub ntiag ntawm ib tug muaj zog acid raws li lub catalyst whereas Steglich esterification cuam tshuam cov tshuaj tiv thaiv ntawm ib tug carboxylic acid thiab ib tug cawv nyob rau hauv muaj. Dimethylaminopyridine (DMAP) ua ib qho catalyst.
