Qhov Tseem Ceeb - Protic vs Aprotic Solvents
Qhov sib txawv tseem ceeb ntawm protic thiab aprotic cov kuab tshuaj yog cov kuab tshuaj protic muaj cov hydrogen dissociable atoms whereas aprotic solvents tsis muaj dissociable hydrogen atom.
Ib qho hnyav yog cov kua ua kua uas tuaj yeem yaj lwm yam tshuaj. Muaj ntau hom kuab tshuaj uas muaj peev xwm muab faib ua ob pawg ua cov kuab tshuaj polar thiab nonpolar. Cov kuab tshuaj polar tuaj yeem muab faib ua ob pawg ua protic thiab aprotic solvents. Protic solvents tuaj yeem tsim cov ntawv cog lus hydrogen vim tias lawv muaj cov khoom siv tshuaj lom neeg uas xav tau rau kev sib txuas ntawm hydrogen, piv txwv li. O-H daim ntawv cog lus thiab N-H daim ntawv cog lus. Hauv qhov sib piv, cov kuab tshuaj aprotic tsis muaj cov tshuaj tiv thaiv uas xav tau rau hydrogen bonding.
Protic Solvents yog dab tsi?
Cov kuab tshuaj yog cov kuab tshuaj polar uas muaj cov atoms hydrogen dissociable. Cov kuab tshuaj no muaj ntau O-H daim ntawv cog lus thiab N-H daim ntawv cog lus. Lub dissociable hydrogen atoms yog cov uas muaj kev sib raug zoo rau oxygen atoms thiab nitrogen atoms nyob rau hauv cov O-H thiab N-H bonds. Yog li ntawd, pawg hydroxyl (-OH) thiab amine pawg (-NH2) yog cov khoom tseem ceeb hauv cov kuab tshuaj tiv thaiv.
Cov kuab tshuaj muaj zog sib koom ion yaj lub zog nrog cov kuab tshuaj aprotic thiab yog cov kua qaub (vim lawv tuaj yeem tso cov protons). Lub dielectric qhov tsis tu ncua ntawm cov kuab tshuaj protic no siab heev (dielectric tas li yog cov khoom ntawm cov khoom siv hluav taws xob insulating thiab yog qhov ntsuas qhov muaj peev xwm ntawm cov khoom siv los khaws cov hluav taws xob hauv hluav taws xob).
Piv txwv ntawm cov kuab tshuaj muaj xws li dej, cawv xws li methanol thiab ethanol, hydrogen fluoride (HF), thiab ammonia (NH 3). Cov kuab tshuaj no feem ntau yog siv los yaj cov ntsev. Polar protic kuab tshuaj nyiam mus rau SN1 cov tshuaj tiv thaiv.
Aprotic Solvents yog dab tsi?
Aprotic cov kuab tshuaj yog cov kuab tshuaj polar uas tsis muaj hydrogen atoms dissociable. Cov kuab tshuaj no tsis muaj tshuaj lom neeg xws li O-H bonds thiab N-H bonds. Yog li, cov kuab tshuaj aprotic tsis muaj pawg hydroxyl (-OH) thiab pawg amine (-NH2) thiab tsis tuaj yeem tsim cov ntawv cog lus hydrogen.
Aprotic cov kuab tshuaj sib koom ion yaj lub zog nrog cov kuab tshuaj protic. Cov kuab tshuaj aprotic no tsis muaj acidic hydrogen, yog li tsis muaj kev tso tawm ntau ntawm hydrogen ions. Polar aprotic cov kuab tshuaj muaj qis lossis nruab nrab dielectric qhov tseem ceeb. Cov kuab tshuaj no qhia txog qhov nruab nrab polarity.
Daim duab 01: Kev Sib Piv Ntawm Protic thiab Aprotic Solvents
Piv txwv ntawm cov kuab tshuaj aprotic suav nrog dichloromethane (DCM), tetrahydrofuran (THF), ethyl acetate, thiab acetone. Cov kuab tshuaj aprotic tuaj yeem siv los yaj cov ntsev. Cov kuab tshuaj no nyiam dhau SN2 cov tshuaj tiv thaiv.
Dab tsi yog qhov zoo sib xws ntawm Protic thiab Aprotic Solvents?
- Ob leeg Protic thiab Aprotic Solvents yog cov kuab tshuaj polar.
- Ob leeg Protic thiab Aprotic Solvents cov kuab tshuaj tuaj yeem yaj cov ntsev.
Qhov txawv ntawm Protic thiab Aprotic Solvents yog dab tsi?
Protic vs Aprotic Solvents |
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| Cov kuab tshuaj tiv thaiv yog cov kua roj ntsha polar uas muaj cov atoms hydrogen dissociable. | Aprotic cov kuab tshuaj yog cov kua nruab nrog cev uas tsis muaj hydrogen atoms dissociable. |
| Hydrogen Bond Formation | |
| Cov kuab tshuaj tiv thaiv muaj peev xwm ntawm hydrogen daim ntawv cog lus. | Aprotic cov kuab tshuaj tsis tuaj yeem tsim cov ntawv cog lus hydrogen. |
| Acidity | |
| Protic kuab tshuaj yog acidic. | Aprotic cov kuab tshuaj tsis yog acidic. |
| Chemical Bonds Present | |
| Cov kuab tshuaj muaj txiaj ntsig yog nplua nuj nrog O-H daim ntawv cog lus thiab N-H daim ntawv cog lus. | Aprotic cov kuab tshuaj tsis muaj O-H daim ntawv cog lus thiab N-H daim ntawv cog lus. |
| Dielectric Constant | |
| Protic kuab tshuaj muaj qhov dielectric siab tas li. | Aprotic cov kuab tshuaj muaj qhov dielectric qis. |
| hom kev xav zoo tshaj | |
| Cov kuab tshuaj tiv thaiv nyiam kom dhau SN1 cov tshuaj tiv thaiv. | Aprotic cov kuab tshuaj nyiam kom dhau SN2 cov tshuaj tiv thaiv. |
Summary – Protic vs Aprotic Solvents
Cov kuab tshuaj yog cov kua uas muaj peev xwm ua kom cov tshuaj yaj. Cov kuab tshuaj muaj nyob rau hauv ob hom loj xws li cov kuab tshuaj polar thiab nonpolar solvents. Polar solvents tuaj yeem muab faib ua ob pawg ua cov kuab tshuaj protic thiab cov kuab tshuaj aprotic. Qhov txawv ntawm cov kuab tshuaj protic thiab aprotic yog tias cov kuab tshuaj protic muaj cov tshuaj hydrogen dissociable thaum cov kuab tshuaj aprotic tsis muaj hydrogen atom dissociable.
