Carboxylic Acid vs Alcohol
Carboxylic acids thiab cawv yog cov organic molecules nrog cov pawg ua haujlwm polar. Ob leeg muaj peev xwm ua tau cov ntawv cog lus hydrogen, uas cuam tshuam rau lawv lub cev zoo li cov ntsiab lus kub.
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. Qhov no carboxylic acid hu ua formic acid. Tsis tas li ntawd, R pab pawg tuaj yeem ua cov saw hlau ncaj nraim, cov saw saw caj dab, cov tshuaj tsw qab, 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 yog muab rau naj npawb 1. 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 uas tsis hloov pauv.
Alcohol
Tus yam ntxwv ntawm tsev neeg cawv yog muaj -OH ua haujlwm pab pawg (hydroxyl pawg). Feem ntau, pawg -OH no txuas nrog sp 3hybridized carbon. Cov tswv cuab yooj yim ntawm tsev neeg yog methyl cawv, uas tseem hu ua methanol. Cawv tuaj yeem muab faib ua peb pawg ua thawj, theem nrab thiab theem nrab. Qhov kev faib tawm no yog nyob ntawm qib kev hloov pauv ntawm cov pa roj carbon uas cov pawg hydroxyl txuas ncaj qha. Yog tias cov pa roj carbon tsuas muaj lwm cov pa roj carbon txuas nrog rau nws, cov pa roj carbon tau hais tias yog thawj cov pa roj carbon thiab cawv yog thawj cov cawv. Yog tias cov pa roj carbon nrog cov pab pawg hydroxyl txuas nrog ob lwm cov pa roj carbon monoxide, ces qhov ntawd yog cov cawv thib ob thiab lwm yam. Cov dej cawv muaj npe nrog lub ntsiab lus -ol raws li IUPAC nomenclature. Ua ntej, qhov txuas txuas txuas ntev tshaj plaws uas cov pawg hydroxyl txuas ncaj qha yuav tsum raug xaiv. Tom qab ntawd lub npe ntawm cov sib raug zoo alkane raug hloov los ntawm kev tso tus kawg e thiab ntxiv cov lus rau ol.
Cawv muaj qhov kub hnyiab ntau dua li cov hydrocarbons lossis ethers. Yog vim li cas rau qhov no yog qhov muaj kev sib cuam tshuam ntawm cov cawv molecules los ntawm hydrogen bonding. Yog tias pawg R yog me me, cawv yog miscible nrog dej, tab sis raws li cov pab pawg R tau loj dua, nws zoo li hydrophobic. Cawv yog polar. C-O daim ntawv cog lus thiab O-H daim ntawv cog lus ua rau lub polarity ntawm cov molecule. Polarization ntawm O-H daim ntawv cog lus ua rau cov hydrogen ib feem zoo thiab piav qhia txog acidity ntawm cawv. Cawv yog cov tsis muaj zog acids, thiab cov acidity yog ze rau cov dej. -OH yog ib pab pawg neeg pluag, vim OH– yog lub hauv paus muaj zog.
Qhov txawv ntawm Carboxylic Acid thiab Cawv yog dab tsi?
• Cov pab pawg ua haujlwm ntawm carboxylic acid yog -COOH, thiab hauv cawv yog -OH.
• Thaum ob pab pawg nyob hauv ib lub molecule, qhov tseem ceeb yog muab rau carboxylic acid nyob rau hauv lub npe.
• Carboxylic acids muaj acidity ntau dua piv rau cov cawv sib xws.
• pawg Carboxylic thiab pawg -OH muab cov yam ntxwv ncov hauv IR thiab NMR spectra.
