Carboxylic Acid vs Ester
Carboxylic acids thiab esters yog cov organic molecules nrog pab pawg -COO. Ib qho oxygen atom yog sib koom ua ke rau carbon nrog ob daim ntawv cog lus, thiab lwm yam oxygen yog sib koom nrog ib daim ntawv cog lus. Txij li thaum tsuas yog peb lub atom txuas nrog cov pa roj carbon atom, nws muaj trigonal planar geometry nyob ib ncig ntawm nws. Ntxiv mus, cov pa roj carbon atom yog sp2 hybridized. Carboxyl pawg yog ib pawg ua haujlwm dav dav hauv chemistry thiab bio chemistry. Cov pab pawg no yog niam txiv ntawm tsev neeg muaj feem xyuam nrog cov tshuaj hu ua acyl compounds. Acyl compounds tseem hu ua carboxylic acid derivatives. Ester yog carboxylic acid derivative zoo li ntawd.
Y Carboxylic Acid
Carboxylic acids yog cov organic tebchaw uas muaj pawg ua haujlwm -COOH. Cov pab pawg no hu ua pawg carboxyl. Carboxylic acid muaj cov qauv dav dav raws li hauv qab no.
Nyob hauv hom yooj yim tshaj plaws ntawm carboxylic acid, R pawg sib npaug rau H. Cov carboxylic acid no hu ua formic acid. Txawm hais tias formic acid, muaj ntau ntau hom carboxylic acids nrog ntau pawg R. Cov pawg R tuaj yeem yog cov saw hlau ncaj nraim, cov saw caj dab, pab pawg muaj ntxhiab, thiab lwm yam. acetic acid, hexanoic acid, thiab benzoic acid yog qee qhov piv txwv rau carboxylic acids. Hauv IUPAC nomenclature, carboxylic acids muaj npe los ntawm kev poob qhov kawg - e ntawm lub npe ntawm alkane sib raug rau cov saw ntev tshaj plaws hauv cov kua qaub thiab ntxiv -oic acid. Ib txwm, cov carboxyl carbon tau muab tus lej 1. Raws li qhov no, IUPAC lub npe rau acetic acid yog ethanoic acid. Lwm yam tshaj li cov npe IUPAC, ntau cov carboxylic acids muaj cov npe.
Carboxylic acids yog polar molecules. Vim yog pawg -OH, lawv tuaj yeem tsim muaj zog hydrogen bonds nrog ib leeg, thiab nrog dej. Yog li ntawd, carboxylic acids muaj cov ntsiab lus kub kub. Tsis tas li ntawd, carboxylic acids nrog qis molecular hnyav yooj yim yaj hauv dej. Txawm li cas los xij, raws li qhov ntev ntawm cov saw hlau txuas ntxiv, cov solubility txo qis. Carboxylic acids muaj acidity xws li pKa 4-5. Txij li thaum lawv yog acidic, lawv teb tau yooj yim nrog NaOH thiab NaHCO 3 cov kev daws teeb meem los tsim cov ntsev ntsev. Carboxylic acids zoo li acetic acid yog cov tsis muaj zog acids, thiab lawv muaj nyob rau hauv kev sib npaug nrog nws cov conjugate puag hauv aqueous media. Txawm li cas los xij, yog tias cov carboxylic acids muaj cov electron tshem tawm pawg xws li Cl, F, lawv yog acidic dua li cov kua qaub tsis hloov.
Ester
Esters muaj cov qauv dav dav ntawm RCOOR '. Esters yog tsim los ntawm cov tshuaj tiv thaiv ntawm carboxylic acid nrog cawv. Esters muaj npe los ntawm kev sau cov npe ntawm cov cawv uas tau muab los ua ntej. Tom qab ntawd lub npe muab los ntawm cov kua qaub yog sau nrog qhov xaus - noj lossis - oate. Piv txwv li, ethyl acetate yog lub npe ntawm cov ester hauv qab no.
Esters yog polar compounds. Tab sis lawv tsis muaj peev xwm tsim muaj zog hydrogen bonds rau ib leeg vim tsis muaj hydrogen bounded rau oxygen. Yog li ntawd, esters muaj cov ntsiab lus kub qis dua piv rau cov kua qaub lossis cawv nrog cov khoom hnyav zoo sib xws. Feem ntau esters muaj cov ntxhiab tsw qab ntxiag, uas yog lub luag haujlwm tsim cov ntxhiab tsw ntawm txiv hmab txiv ntoo, paj, thiab lwm yam.
Qhov txawv ntawm Carboxylic Acid thiab Ester yog dab tsi?
• Esters yog carboxylic acid derivatives.
• Carboxylic acids muaj cov qauv dav dav ntawm RCOOH. Esters muaj cov qauv dav dav ntawm RCOOR'.
• Carboxylic acids tuaj yeem ua kom muaj zog hydrogen bonds, tab sis esters tsis tuaj yeem.
• Boiling cov ntsiab lus ntawm esters qis dua cov carboxylic acids.
• Muab piv rau qis molecular hnyav acids, esters feem ntau muaj ntxhiab tsw qab ntxiag.
