21691-50-9 L-Ala-Otbu ib

Nws yog tsim los ntawm cov tshuaj tiv thaiv esterization ntawm inorganic acid lossis organic acid lossis cawv.Cawv lossis phenol lossis acidic anhydride, cawv thiab ethylene, tsis muaj acidic acid thiab fatty nitrogen derivatives tuaj yeem tsim ester.Cov hydrogen ntawm alpha-carbon hauv cov ester molecules poob ib qho cawv molecular nrog lwm cov ester molecular nyob rau hauv alkaline tej yam kev mob los tsim β-keto ester, uas yog hu ua ester contraction cov tshuaj tiv thaiv.Piv txwv li, acetyl acetate yog tsim los tsim acetyl ethyl acetate.Cov tshuaj tiv thaiv no tseem ceeb heev hauv cov organic synthesis.
Lub npe ntawm ester los ntawm cov npe sib xws ntawm carboxylic acid thiab cawv lossis phenol, xws li "ib yam kua qaub thiab qee yam ester".Lub voj voog esters hu ua lactone (lactone).Cov khoom siv tshuaj lom neeg ntawm ester zoo ib yam li amyl niche anhydride, uas yog nquag hydrolysis, cawv thiab ammonia cov tshuaj tiv thaiv.Qib qis ester yog cov tshuaj tsw qab thiab tsis muaj xim tsis muaj xim, thiab cov ester qib siab yog khoom.Estes yog cov kuab tshuaj tseem ceeb thiab cov khoom siv hluavtaws, thiab qee cov esters yog cov tshuaj lawv tus kheej.Raws li hom kua qaub, ester tuaj yeem muab faib ua inorganic acid ester thiab organic acid ester.Etate, ethyl acetate yog fatty ester, acetate yog aromatic ester, thiab namanonate yog cyclic ester.
Cov ester feem ntau yog cov kua nruab nrab tsis muaj xim.Cov ester tsim los ntawm cov haiv neeg rog thiab cov dej cawv saturated muaj cov txiv hmab txiv ntoo aroma, uas tuaj yeem yaj hauv dej, thiab nws kuj nyuaj rau yaj hauv dej.Qee qhov ester lub teeb nyem qis thiab feem ntau hlawv.Cov pa tuaj yeem nqus tau los ntawm txoj hlab ntsws, thiab cov kua ester tuaj yeem nqus tau los ntawm daim tawv nqaij.Tom qab nqus tau, nws tau yaj hauv cov ntshav, thiab qee qhov ntawm lawv tawm hauv lub ntsws thiab lub raum.Tom qab qee qhov hydrolysis, tig mus rau hauv cov txheej txheem metabolic.Ntxiv nrog rau ob peb ntawm cov ester tebchaw, feem ntau ntawm lawv yog cov tshuaj lom thiab muaj kuab lom heev, thiab feem ntau ntawm lawv yog micro-toxic rau cov tshuaj lom nruab nrab, thiab ntau yam tsis muaj tshuaj lom.Muaj 38 esters nyob rau hauv lub aroma ntawm tshuaj yej.Feem ntau: ① fatty ester: tsim los ntawm cawv thiab roj, xws li ethyl acetate, hexyl hexyate.② Aromatic ester: tsim los ntawm cawv thiab aromatic acid, xws li Shun-3-hexylzyl.③ Circin esters: tsim los ntawm cawv thiab cyclocar, xws li jasmone hyacxide.Cov ester feem ntau yog nruab nrab, uas tuaj yeem ua rau hydrolyzed thiab tsim cawv thiab kua qaub.Cov naj npawb carbon tsawg feem ntau yog cov kua roj tsw qab, thiab cov pa roj carbon ntau yog cov kua thiab cov khib nyiab insoluble hauv dej.