Qhov sib txawv tseem ceeb ntawm Hofmann thiab Curtius rearrangement yog Hofmann rearrangement piav qhia txog kev hloov pauv ntawm thawj amide rau hauv thawj amine whereas Curtius rearrangement piav qhia txog kev hloov pauv ntawm acyl azide rau hauv isocyanate.
Ib qho tshuaj tiv thaiv rov qab yog cov tshuaj hloov pauv tshuaj uas ib qho tshuaj lom neeg hloov mus rau hauv ib qho chaw sib txawv uas ruaj khov dua li cov khoom qub qub. Hofmann thiab Curtius rearrangement yog ob hom tshuaj lom neeg cov tshuaj tiv thaiv uas muaj ntau daim ntawv thov hauv cov txheej txheem chemical synthesis. Cov tshuaj tiv thaiv Hofmann tau tsim thiab muaj npe tom qab tus kws tshawb fawb Lub Yim Hli Wilhelm Von Hofmann thaum Curtius rov kho cov tshuaj tiv thaiv raug hu ua Theodor Curtius.
Hofmann Rearrangement yog dab tsi?
Hofmann rearrangement yog ib hom tshuaj tiv thaiv uas piav qhia txog kev hloov pauv ntawm thawj amide mus rau hauv thawj amine nrog tsawg dua carbon atom. Cov tshuaj tiv thaiv no tau muaj npe tom qab Lub Yim Hli Wilhelm Von Hofmann. Qee zaum, peb hu nws tias Hofmann degradation thiab. Cov qauv dav dav rau Hofmann rearrangement cov tshuaj tiv thaiv yog raws li nram no:
Daim duab 01: Hofmann Rearrangement
Hofmann rov kho cov tshuaj tiv thaiv pib nrog cov tshuaj tiv thaiv ntawm bromine nrog sodium hydroxide, uas tsim sodium hypobromite (ib qho tshuaj tiv thaiv hauv situ) uas tuaj yeem hloov pauv thawj amide mus rau hauv nruab nrab isocyanate molecule. Tom qab ntawd qhov no intermediate isocyanate compound undergoes hydrolysis los muab cov amine thawj. Thaum qhov kev hloov kho no, cov pa roj carbon dioxide molecule raug tso tawm. Yog li ntawd, cov khoom kawg tsis muaj ib qho carbon atom thaum piv rau cov pa roj carbon atoms hauv thawj molecule.
Curtius Rearrangement yog dab tsi?
Curtius rearrangement yog ib hom tshuaj tiv thaiv uas acyl azide hloov mus rau hauv isocyanate. Cov tshuaj tiv thaiv no tau tsim los ntawm Theodor Curtius hauv xyoo 1885. Nws yog cov tshuaj tiv thaiv thermal decomposition. Cov tshuaj tiv thaiv no cuam tshuam qhov poob ntawm cov roj nitrogen molecule. Tom qab hloov dua siab tshiab no, lub isocyanate molecule raug kev tawm tsam los ntawm ntau yam nucleophiles - piv txwv li. dej, cawv, thiab amines. Qhov kev tawm tsam nucleophilic no ua rau thawj amine, carbamate, lossis urea derivatives. Cov qauv dav dav yog raws li hauv qab no:
Daim duab 02: Curtius Rearrangement
Ib daim ntawv acyl azide los ntawm cov tshuaj tiv thaiv ntawm cov tshuaj chlorides lossis anhydrides nrog sodium azide lossis trimethylsilyl azide. Feem ntau, Curtius rearrangement yog suav tias yog ob-kauj ruam txheej txheem. Qhov poob ntawm nitrogen gas tsim ib qho acyl nitriene. Thiab, qhov tshuaj tiv thaiv no yog ua raws li kev tsiv teb tsaws ntawm R-pab pawg kom muab cov isocyante. Txawm li cas los xij, raws li kev tshawb fawb tshawb fawb tsis ntev los no, thermal decomposition ntawm acyl azide yog ib qho kev sib koom ua ke uas ob qho tib si hais saum toj no tshwm sim ua ke. Qhov no tshwm sim vim qhov tsis muaj nitrene ntxig lossis ntxiv cov khoom lag luam pom lossis cais tawm hauv cov tshuaj tiv thaiv.
Qhov txawv ntawm Hofmann thiab Curtius Kev Hloov Kho yog dab tsi?
Ib qho tshuaj tiv thaiv rov qab yog cov tshuaj tiv thaiv tshuaj uas hloov cov pa roj carbon monoxide rau hauv cov qauv sib txawv uas yog ib qho isomer ntawm cov khoom qub. Qhov sib txawv tseem ceeb ntawm Hofmann thiab Curtius rearrangement yog tias Hofmann rearrangement piav qhia txog kev hloov pauv ntawm thawj amide rau hauv thawj amine thaum Curtius rearrangement piav qhia txog kev hloov pauv ntawm acyl azide rau hauv isocyanate.
Hauv qab infographic tabulates qhov sib txawv ntawm Hofmann thiab Curtius rearrangement.
Summary – Hofmann vs Curtius Rearrangement
Hofmann thiab Curtius rearrangement yog ob hom tshuaj kho cov tshuaj tiv thaiv. Qhov sib txawv tseem ceeb ntawm Hofmann thiab Curtius rearrangement yog tias Hofmann rearrangement piav qhia txog kev hloov pauv ntawm thawj amide rau hauv thawj amine whereas Curtius rearrangement piav qhia txog kev hloov pauv ntawm acyl azide rau hauv isocyanate.
