Qhov Tseem Ceeb Qhov Sib Txawv - E1 vs E2 Reactions
Cov tshuaj tiv thaiv E1 thiab E2 yog ob hom kev tshem tawm cov tshuaj tiv thaiv uas sib txawv raws li cov txheej txheem ntawm kev tshem tawm; kev tshem tawm tuaj yeem yog ib kauj ruam lossis ob kauj ruam txheej txheem. Qhov sib txawv tseem ceeb ntawm E1 thiab E2 cov tshuaj tiv thaiv yog tias E1 cov tshuaj tiv thaiv muaj cov txheej txheem tshem tawm tsis zoo thaum E2 cov tshuaj tiv thaiv muaj cov txheej txheem tshem tawm bimolecular.
Nyob rau hauv cov organic chemistry, tshem tawm cov tshuaj tiv thaiv yog ib hom tshuaj lom neeg tshwj xeeb uas cov tshuaj hloov pauv tau raug tshem tawm (tshem tawm) los ntawm cov organic tebchaw.
E1 Kev Pom Zoo yog dab tsi?
E1 cov tshuaj tiv thaiv yog ib hom kev tshem tawm ob kauj ruam pom muaj nyob hauv cov tshuaj lom neeg. Hauv kev tshem tawm cov tshuaj tiv thaiv no, cov khoom hloov pauv hauv cov organic tebchaw raug tshem tawm lossis tshem tawm. Cov tshuaj tiv thaiv mechanisms ntawm E1 cov tshuaj tiv thaiv yog hu ua unimolecular tshem tawm.
E1 cov tshuaj tiv thaiv yog ob-kauj ruam, uas txhais tau tias, E1 cov tshuaj tiv thaiv tshwm sim los ntawm ob kauj ruam hu ua ionization thiab deprotonation. Nyob rau hauv cov txheej txheem ionization, ib qho carbocation yog tsim los ntawm kev tshem tawm cov khoom hloov. Hauv theem thib ob (deprotonation), cov carbocation yog ruaj khov los ntawm kev tshem tawm hydrogen atom ua proton.
Feem ntau, E1 cov tshuaj tiv thaiv tshwm sim nrog tertiary alkyl halides. Tab sis qee zaum, theem nrab alkyl halide kuj tau txais hom kev tshem tawm no. Muaj ob qho laj thawj rau qhov no; bulky alkyl halides (hloov pauv heev) tsis tuaj yeem ua rau E2 cov tshuaj tiv thaiv, thiab cov carbocations hloov pauv tau ruaj khov dua li cov carbocations thawj lossis theem nrab. Hauv E1 cov tshuaj tiv thaiv, kev tsim cov carbocation yog qib qis tshaj. Yog li ntawd, nws yog tus nqi-txhais kauj ruam pf E1 cov tshuaj tiv thaiv, thiab cov tshuaj tiv thaiv tus nqi tsuas yog nyob ntawm qhov concentration ntawm alkyl halide.
Daim duab 01: Mechanism of E1-Reaction in Organic Chemistry
E1 cov tshuaj tiv thaiv feem ntau tshwm sim thaum tsis muaj cov hauv paus tiav lossis muaj cov hauv paus tsis muaj zog. Acidic tej yam kev mob thiab kub kub yog nyiam rau kev vam meej E1 cov tshuaj tiv thaiv. Thiab tseem, E1 cov tshuaj tiv thaiv muaj xws li carbocation rearrangement cov kauj ruam.
E2 Cov Lus Teb yog dab tsi?
E2 cov tshuaj tiv thaiv yog ib hom kev tshem tawm ib kauj ruam pom muaj nyob rau hauv cov organic chemistry. Hauv kev tshem tawm cov tshuaj tiv thaiv no, cov khoom hloov pauv hauv cov organic tebchaw raug tshem tawm lossis tshem tawm hauv ib kauj ruam. Cov tshuaj tiv thaiv mechanisms ntawm E2 cov tshuaj tiv thaiv yog hu ua bimolecular tshem tawm.
Cov tshuaj tiv thaiv E2 yog ib kauj ruam tshem tawm cov tshuaj tiv thaiv nrog ib lub xeev hloov pauv. Yog li ntawd, cov tshuaj tiv thaiv kev puas tsuaj thiab tsim tshwm sim nyob rau hauv tib kauj ruam. Hom tshuaj tiv thaiv no feem ntau pom muaj nyob hauv thawj alkyl halides. Tab sis qhov no kuj tuaj yeem pom nyob rau hauv qee qhov theem nrab alkyl halides. Cov tshuaj tiv thaiv muaj ob lub tebchaw; alkyl halide thiab lub hauv paus. Li no nws yog hu ua bimolecular cov tshuaj tiv thaiv. E2 kev tshwm sim tshwm sim nyob rau hauv lub xub ntiag ntawm lub hauv paus muaj zog. Feem ntau piv txwv rau E2 cov tshuaj tiv thaiv yog dehydrohalogenation.
Daim duab 02: Ib qho E2 Kev Sib Tham Mechanism
Qhov cuam tshuam rau tus nqi ntawm E2 cov tshuaj tiv thaiv yog lub zog ntawm lub hauv paus (lub zog ntau dua ntawm lub hauv paus, siab dua cov tshuaj tiv thaiv), hom hnyav (polar protic solvents nce cov tshuaj tiv thaiv), xwm txheej ntawm pawg tawm (zoo dua cov pab pawg tawm, siab dua cov tshuaj tiv thaiv).
Dab tsi yog qhov zoo sib xws ntawm E1 thiab E2 Kev Pom Zoo?
- Ob qho E1 thiab E2 Cov Lus Teb yog hom kev tshem tawm cov tshuaj tiv thaiv.
- Ob qhov kev cuam tshuam yog nyiam los ntawm cov kuab tshuaj polar protic.
- Ob hom kev tshwm sim tuaj yeem pom nyob rau hauv theem nrab alkyl halides.
- Tus nqi ntawm ob qho kev tawm tsam yog nce ntxiv yog tias muaj cov pab pawg zoo dua tuaj nyob hauv alkyl halide.
Qhov txawv ntawm E1 thiab E2 Kev Pom Zoo yog dab tsi?
E1 vs E2 Reactions |
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| E1 cov tshuaj tiv thaiv yog ib hom kev tshem tawm ob-kauj ruam pom muaj nyob hauv cov tshuaj lom neeg. | E2 cov tshuaj tiv thaiv yog ib hom kev tshem tawm ib kauj ruam pom muaj nyob rau hauv cov organic chemistry. |
| Base | |
| Cov tshuaj tiv thaiv E1 tshwm sim nyob rau hauv qhov tsis ua tiav ntawm lub hauv paus lossis nyob rau hauv lub xub ntiag ntawm lub hauv paus tsis muaj zog. | E2 kev tshwm sim tshwm sim nyob rau hauv lub xub ntiag ntawm lub hauv paus muaj zog. |
| Cov tshuaj tiv thaiv ntawm E1 cov tshuaj tiv thaiv yog hu ua unimolecular tshem tawm. | Cov tshuaj tiv thaiv ntawm E2 cov tshuaj tiv thaiv yog hu ua bimolecular tshem tawm. |
| E1 cov tshuaj tiv thaiv yog ob theem kev tshwm sim. | Cov tshuaj tiv thaiv E2 yog ib kauj ruam tshem tawm cov tshuaj tiv thaiv. |
| Carbocation Formation | |
| E1 cov tshuaj tiv thaiv tsim cov carbocations ua cov sib xyaw nruab nrab. | E2 cov tshuaj tiv thaiv tsis tsim cov carbocation. |
| Lwm Lub Npe | |
| E1 cov tshuaj tiv thaiv yog lub npe hu ua kev tshem tawm tsis zoo. | E2 cov tshuaj tiv thaiv yog hu ua bimolecular tshem tawm. |
| Examples | |
| E1 cov tshuaj tiv thaiv muaj nyob hauv tertiary alkyl halides thiab qee qhov thib ob alkyl halides. | E2 cov tshuaj tiv thaiv muaj nyob hauv thawj alkyl halides thiab qee qhov thib ob alkyl halides. |
Summary – E1 vs E2 Reactions
Kev tshem tawm cov tshuaj tiv thaiv yog tshuaj lom neeg uas cov pab pawg hloov pauv raug tshem tawm los ntawm cov organic tebchaw; tshwj xeeb tshaj yog los ntawm alkyl halides. Qhov txawv ntawm E1 thiab E2 cov tshuaj tiv thaiv yog tias E1 cov tshuaj tiv thaiv muaj cov txheej txheem tshem tawm tsis zoo thaum E2 cov tshuaj tiv thaiv muaj cov txheej txheem tshem tawm bimolecular.
