Qhov sib txawv tseem ceeb ntawm aldehyde thiab cawv yog tias aldehyde muaj -CHO ua haujlwm pab pawg thaum cawv muaj -OH pab pawg ua haujlwm.
Aldehydes thiab cawv yog cov organic tebchaw. Lawv muaj cov pab pawg ua haujlwm sib txawv, nrog rau cov khoom sib txawv ntawm cov tshuaj thiab lub cev. Ib qho aldehyde muaj carbonyl carbon atom (cov pa roj carbon atom txuas rau cov pa oxygen los ntawm ob daim ntawv cog lus), tab sis tsis muaj cov chaw carbonyl hauv cawv. Ob leeg aldehydes thiab cawv yog ib qho tseem ceeb heev hauv cov organic synthesis tshuaj, raws li precursors rau lwm cov tebchaw xws li ketones.
Aldehyde yog dab tsi?
Aldehydes yog cov organic tebchaw uas muaj -CHO pab pawg ua haujlwm. Yog li ntawd, nws muaj qhov chaw carbonyl (-C=O). Cov mis loj ntawm ib qho aldehyde yog R-CHO, qhov twg R pawg tuaj yeem yog aromatic lossis aliphatic. Yog li, pawg R txiav txim siab qhov kev ua haujlwm ntawm cov organic molecule. Ntxiv mus, aromatic aldehydes yog tsawg reactive tshaj li aliphatic aldehydes.
Daim duab 01: Cov qauv dav dav ntawm Aldehyde
Aromatic muaj lawv -CHO pab pawg txuas nrog ib pawg aromatic. Txawm li cas los xij, siv lub npe no thaum muaj ib pab pawg tsw qab nyob rau hauv aldehyde. Ntxiv rau cov no, cov pab pawg muaj ntxhiab tsw muaj huab cua delocalized pi-electron vim yog qhov sib txuas ntawm pi daim ntawv cog lus (hloov qauv ntawm ib daim ntawv cog lus thiab ob daim ntawv cog lus).
Aliphatic aldehydes tsis muaj lub nplhaib uas muaj ntxhiab txuas nrog -CHO pab pawg. Tsis tas li ntawd, cov molecules no tsis muaj lub nplhaib uas muaj ntxhiab uas txuas nrog rau qhov sib xyaw. Txij li thaum tsis muaj cov nplhaib uas muaj ntxhiab, cov molecules no tsis muaj resonance stabilization thiab. Li no, cov molecules no muaj cov electrophilic -CHO pawg, ua rau cov reactivity ntawm molecules siab heev.
Alcohol yog dab tsi?
Cawv yog cov organic tebchaw uas muaj ib lossis ntau pawg hydroxyl (-OH). Cov molecules no yog tsim los ntawm C, H thiab O atoms. Cov atoms no tau teeb tsa hauv pawg alkyl thiab hydroxyl pawg. Cov pab pawg hydroxyl txuas mus rau ib qho carbon atom ntawm pawg alkyl.
Daim duab 02: Tus Qauv General ntawm Cawv
Peb tuaj yeem tsim cov cawv los ntawm ntau txoj hauv kev: Piv txwv li. Ziegler thiab oxo cov txheej txheem, hydration cov tshuaj tiv thaiv, kev lom neeg xws li fermentation, thiab lwm yam. Ib qho cawv tuaj yeem ua raws li qhov pib molecule lossis nruab nrab rau kev sib txuas ntawm lwm cov organic tebchaw. Ntxiv mus, qee cov dej haus muaj cawv ua ib qho tseem ceeb lossis me. Qee lub sij hawm cov cawv tuaj yeem siv los ua cov kuab tshuaj rau kev ua kom huv ntawm cov tebchaw tawm ntawm cov khoom tsis huv.
Muaj peb hom cawv uas yog thawj, theem nrab thiab qib theem dej cawv. Thawj cov cawv yog tsim los ntawm ib pawg hydroxyl uas txuas nrog cov pa roj carbon atom ntawm pawg alkyl uas txuas nrog tsuas yog ib pawg alkyl. Cov cawv thib ob, ntawm qhov tod tes, yog tsim los ntawm cov pa roj carbon atom uas txuas nrog ib pawg hydroxyl thiab ob pawg alkyl. Ntxiv mus, tertiary cawv yog tsim los ntawm cov pa roj carbon atom uas yog sib koom ua ke rau ib pawg hydroxyl thiab nrog peb pawg alkyl.
Qhov txawv ntawm Aldehyde thiab cawv yog dab tsi?
Aldehydes thiab cawv yog cov organic tebchaw. Lawv muaj cov pab pawg ua haujlwm sib txawv, ua rau muaj cov tshuaj lom neeg thiab lub cev sib txawv. Qhov sib txawv tseem ceeb ntawm aldehyde thiab cawv yog tias aldehyde muaj -CHO ua haujlwm pab pawg thaum cawv muaj -OH pab pawg ua haujlwm. Tsis tas li, lwm qhov sib txawv ntawm aldehyde thiab cawv yog tias muaj carbonyl carbon nyob rau hauv ib qho aldehyde, tab sis tsis muaj cov chaw carbonyl hauv cawv.
Ntxiv mus, peb tuaj yeem tsim cov aldehyde ntawm txoj kev oxidative thiab xws li cawv oxidation, thaum peb tuaj yeem tsim cawv hauv peb txoj kev loj: Ziegler thiab oxo cov txheej txheem, dej tshuaj tiv thaiv, thiab kev lom neeg xws li fermentation.
Hauv qab no yog cov ntsiab lus ntawm qhov sib txawv ntawm aldehyde thiab cawv.
Summary – Aldehyde vs Alcohol
Aldehydes thiab cawv yog cov organic tebchaw. Lawv muaj cov pab pawg ua haujlwm sib txawv, ua rau muaj cov tshuaj lom neeg thiab lub cev sib txawv. Qhov sib txawv tseem ceeb ntawm aldehyde thiab cawv yog tias aldehyde muaj -CHO pab pawg ua haujlwm, thaum cawv muaj -OH pab pawg ua haujlwm.
