Tshuaj thaj chaw ntawm alcohols

Hydrocarbon derivatives nrog ib tug los yog ntau tshaj hydrogen atoms nyob rau hauv lub molecule, pawg rau -OH pab pawg neeg (cov hydroxyl pab pawg neeg los yog tej cov hydroxy pab pawg neeg), - nws alcohols. Cov tshuaj zog txiav txim los ntawm ib tug hydrocarbon radical thiab ib tug hydroxyl pab pawg neeg. Alcohols tsim cais homologous series therein tus neeg sawv cev ntawm txhua successive txawv los ntawm lub ntej neeg rau homology txawv coj = CH2. Tag nrho cov tshuaj ntawm no hauv chav kawm ntawv muaj peev xwm yuav sawv cev los ntawm cov mis: R-OH. Rau tebchaw monohydric limiting general tshuaj mis yog CnH2n + 1OH. Raws li thoob ntiaj teb nomenclature npe tej zaum yuav tsim los ntawm kev ntxiv ib hydrocarbon kaw ol (methanol, ethanol, propanol, etc.).

Qhov no yog ib tug heev muaj ntau haiv neeg thiab ntau chav kawm ntawv ntawm cov tshuaj lub tebchaw. Nyob rau hauv lub xov tooj ntawm -OH pawg nyob rau hauv lub molecule, nws yog muab faib ua mono-, di- thiab trihydric li on - polyhydric compound. Tshuaj thaj chaw ntawm lub alcohols kuj yog nyob ntawm seb cov ntsiab lus ntawm hydroxyl pawg pawg ib molecule. Cov ntaub ntawv yog nruab nrab thiab tsis txhob dissociate rau hauv ions nyob rau hauv dej, xws li muaj zog acids los yog muaj zog bases. Txawm li cas los, tej zaum yuav muaj raws li ib tug weakly acidic (txo nrog qhov kev nce rau hauv tus naj npawb ntawm cov cawv molecular nyhav thiab branching ntawm lub hydrocarbon saw) los yog yooj yim (nce nrog ua molecular nyhav thiab branching molecule) zog.

Tshuaj zog alcohols nyob ntawm seb lub hom thiab spatial arrangement ntawm atoms: yog molecules nrog isomerism saw thiab txoj hauj lwm isomers. Nyob ntawm seb lub siab tshaj plaws pes tsawg tus ntawm ib bonds ntawm cov pa roj carbon atom (hydroxy pab pawg neeg ua txhua yam rau) nrog rau lwm cov carbon atoms (nrog rau cov 1 st, 2 los yog 3) paub qhov txawv thawj (qub), theem nrab los yog tertiary alcohols. Primary alcohols muaj ib tug hydroxyl pab pawg neeg txuas mus rau ib tug thawj carbon atom. Thaum theem nrab thiab tertiary - mus rau lub thib ob thiab tertiary, ntsig txog. Txij li thaum propanol tshwm isomers uas txawv nyob rau hauv qhov chaw ntawm lub hydroxyl neeg: propyl cawv C3H7-OH, thiab isopropyl cawv CH3- (CHOH) -CH3.

Nws yog tsim nyog mus rau npe rau ob peb tug cov ntsiab tshua uas characterize cov tshuaj thaj chaw ntawm alcohols:

1. Thaum interacting nrog alkali hlau los yog hydroxides (deprotonation cov tshuaj tiv thaiv) tsim alcoholates (hydrogen atom yog hloov los ntawm ib tug hlau atom), nyob ntawm seb lub hydrocarbon radical tau los ntawm methoxide, ethoxide, propoxide thiab thiaj li nyob, piv txwv li, sodium propylate: 2CH3CH2OH + 2Na → 2CH3CH2ONa + H2 ↑.
2. Thaum interacting nrog concentrated hydrohalic acid tsim halogenated hydrocarbons: HBr + CH3CH2OH ↔ CH3CH2Br + H2O. Qhov no cov tshuaj tiv thaiv yog reversible. Cov no ib tug nucleophilic muab los ntawm ib tug halogen ion, ib tug hydroxyl pab pawg neeg.
3. Alcohols yuav oxidized rau carbon dioxide, rau aldehydes los yog ketones rau. Alcohols hlawv nyob rau hauv lub xub ntiag ntawm oxygen: 3O2 + C2H5OH → 2CO2 + 3H2O. Nyob rau hauv tus ntawm ib tug muaj zog oxidizing neeg sawv cev (chromic acid, poov tshuaj permanganate , thiab lwm yam) thawj alcohols yog hloov dua siab tshiab rau hauv aldehydes: C2H5OH → CH3COH + H2O, thiab cov theem nrab - mus ketones: CH3- (CHOH) -CH3 → CH3- (Cho) -CH3 + H2O.
4. Lub cev qhuav dej tshuaj tiv thaiv hais raws li qhov cua kub nyob rau hauv lub xub ntiag ntawm dehydrating agents (zinc chloride, sulfuric acid, thiab lwm yam). Qhov no ua alkenes: C2H5OH → CH2 = CH2 + H2O.
5. Lub esterification cov tshuaj tiv thaiv kuj hais raws li qhov cua kub nyob rau hauv lub xub ntiag ntawm dehydrating tebchaw, tab sis, nyob rau hauv sib piv rau lub yav dhau los cov tshuaj tiv thaiv ntawm ib tug sab kub thiab tsim ethers: 2C2H5OH → -C2H5O C2H5O. Nrog sulfuric acid, cov tshuaj tiv thaiv no tshwm sim nyob rau hauv ob ua sawv. Ua ntej, sulfuric acid ester yog tsim: C2H5OH + H2SO4 → C2H5O-SO2OH + H2O, ua raws li los ntawm cua kub los 140 ° C thiab ib tug dhau heev lawm ntawm cov cawv yog tsim, diethyl (feem ntau xa mus rau raws li cov leej faj) ether: C2H5OH + C2H5O-SO2OH → C2H5O-C2H5O + H2SO4 .

Cov tshuaj thaj chaw ntawm polyols, by analogy nrog lawv lub zog yog nyob ntawm seb hom hydrocarbon radical, txoj kev ua ib tug qauv, thiab ntawm cov hoob kawm, tus naj npawb ntawm cov hydroxyl pawg nyob rau ntawd. Piv txwv li, ethylene glycol CH3OH-CH3OH (kub point 197 ° C), uas yog 2 atomic cawv yog ib tug tsis muaj kob kua (a Sweet saj), uas yog tov nrog rau H2O, thiab txo alcohols nyob rau hauv tag nrho cov proportions. Ethylene glycol raws li lub siab homologues ntawd tuaj nyob rau hauv tag nrho cov tshuaj yam ntxwv ntawm monohydric alcohols. Glycerol CH2OH-CHOH-CH2OH (kub point 290 ° C) yog qhov nyuaj tus neeg sawv cev ntawm 3 atomic alcohols. Nws yog ib tug tuab qab zib-saj kua, uas yog hnyav dua dej, tab sis yog tov nrog rau nws nyob rau hauv tej ratio. Soluble nyob rau hauv dej cawv. Rau glycerin thiab nws homologues kuj yus muaj los ntawm tag nrho cov tshuaj tiv thaiv ntawm monohydric alcohols.

Tshuaj zog alcohols txhais cov lus qhia ntawm lawv daim ntawv thov. Lawv yog siv raws li roj (ethanol los yog butanol, etc.), raws li cov kuab tshuaj nyob rau hauv ib tug ntau yam ntawm industries; raws li raw khoom rau zus tau tej cov surfactants thiab detergents; rau lub synthesis ntawm polymeric cov ntaub ntawv. Ib txhia cov neeg sawv cev ntawm no hauv chav kawm ntawv ntawm cov organic tebchaw lug siv raws li lubricants los yog hydraulic kua, thiab kuj rau cov siv thiab ua cov medicaments thiab biologically active tshuaj.