Hemiacetals tuaj yeem ua ke hauv cov tshuaj yooj yim. Tab sis lawv tsis tuaj yeem hnov mob ntxiv los tsim ib qho acetal hauv kev daws teeb meem. … Cyclic hemiacetals yog tsim los ntawm cov suab thaj hauv cov kua dej. Lawv yog qhov ruaj khov txawm tias nyob rau hauv cov kua qaub me ntsis.
Dab tsi ua rau hemiacetals ruaj khov?
Yog li, rau qhov ruaj khov hemiacetal, peb xav tau nrawm hemiacetal-forming cov tshuaj tiv thaiv. Thiab thaum lub hemiacetal yog cyclic uas tsuas yog qhov peb muaj: cov tshuaj tiv thaiv yog intramolecular thiab nucleophilic OH pawg yeej ib txwm nyob ze rau pawg carbonyl, npaj los tawm tsam.
Puas hemiacetals ruaj khov hauv cov kev daws teeb meem?
Yes, hemiacetals ruaj khov hauv kev daws teeb meem. Hauv kev daws teeb meem, CH3O- lossis OH- pawg tsis tuaj yeem raug protonated. Methoxy thiab hydroxyl pawg yog cov pab pawg tsis zoo. Yog li, hauv kev daws teeb meem hemiacetals tsis hloov mus rau hauv Acetals.
Vim li cas acetal tsis ruaj khov hauv cov kua qaub?
Yooj yim ethers muaj qhov cuam tshuam zoo sib xws rau acetals nyob rau hauv cov xwm txheej yooj yim / nucleophilic. Nyob rau hauv cov kua qaub, acetals yog feem ntau ntau reactive vim tias lawv tuaj yeem tsim cov resonance stabilized oxocarbenium ions.
Puas acetals ruaj khov hauv cov kua qaub nruab nrab?
Acetals tsis ruaj khov rau cov kua qaub tab sis ruaj khov rau nruab nrab thiab theem pib cov tshuaj tiv thaiv. Lawv tuaj yeem siv los tiv thaiv cov pab pawg carbonyl uas muab cov theem nruab nrab cov tshuaj tiv thaiv tsis cuam tshuam nrog acidic (Brønsted lossis Lewis) cov tshuaj tiv thaivxwm txheej.
