Video: Vim li cas cov kuab tshuaj polar aprotic zoo rau sn2?
2024 Tus sau: Miles Stephen | [email protected]. Kawg hloov kho: 2023-12-15 23:36
Yog li cov molecules tsawg dua tuaj yeem daws cov anions (nucleophiles). Cov nucleophiles yuav luag unsolvated, yog li nws yooj yim dua rau lawv mus tua lub substrate. Nucleophiles muaj ntau dua nucleophilic hauv aprotic kuab tshuaj . Yog li, SN2 cov tshuaj tiv thaiv "nyiam" aprotic kuab tshuaj.
Ib yam li ntawd, vim li cas cov kuab tshuaj polar aprotic zoo dua li cov kuab tshuaj polar protic rau sn2 cov tshuaj tiv thaiv?
A polar protic kuab tshuaj yuav stabilize qhov carbocation. Tab sis SN2 cov tshuaj tiv thaiv tsis ua hauj lwm zoo polar protic kuab tshuaj vim cov no cov kuab tshuaj ua rau cov nucleophile tsis muaj zog ua rau nws tsawg dua nucleophilic. Polaraprotic kuab tshuaj ua haujlwm zoo heev rau SN2 cov tshuaj tiv thaiv vim lawv tsis solvatenucleophiles.
Ib yam li ntawd, vim li cas sn2 cov tshuaj tiv thaiv nyiam cov kuab tshuaj aprotic? Qhov no yog yog li vim DMSOstabilizes tus nqi sib cais koom nrog hauv kev hloov pauv ntawm ib qho SN2 cov tshuaj tiv thaiv (1 kauj ruam bimolecular tshuaj tiv thaiv ). Lwmpolar aprotic kuab tshuaj kuj siv tau rau tib lub hom phiaj.
Ua raws li qhov no hauv kev txiav txim siab, lub luag haujlwm ntawm aprotic polar solvent hauv sn2 cov tshuaj tiv thaiv yog dab tsi?
Cov SN2 tshuaj tiv thaiv yog nyiam los ntawm polar aprotic kuab tshuaj - cov no yog cov kuab tshuaj xws li acetone, DMSO, acetonitrile, lossis DMF uas yog polar txaus kom yaj cov substrate thiab nucleophile tab sis tsis koom nrog hydrogen bonding nrog nucleophile.
Vim li cas cov kuab tshuaj polar protic zoo rau sn1?
Cov polar protic kuab tshuaj tuaj yeem cuam tshuam nrog electrostatically nrog cov nucleophile li stabilizing nws. Qhov no txo cov reactivity ntawm nucleophile uas nyiam ib qho Sn1 cov tshuaj tiv thaiv tshaj ib qho tshuaj tiv thaiv Sn2.
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