Esters: iimpawu jikelele kunye nesicelo

Esters ka - iimveliso endaweni -athom hydrogen zamaqela hydroxyl ye asidi carboxylic kunye acids nezimbiwa kwi carbon olukhulu. Ukwahlula mono-, khe kunye polyesters. khona mono, asidi khe kunye polybasic, asidi monobasic to - esters ngokupheleleyo kunye acid. Isihloko Ester iqulathe igama, ebandakanyekileyo nokubunjwa yawo acid kunye notywala. Kuba esters, asetyenziswa rhoqo nokuhlelwa apha engenamsebenzi okanye yembali. Ngokutsho amagama nokuhlelwa IUPAC akhiwa esters ngolu hlobo lulandelayo: thatha isihloko utywala inkulu kongezelelwa njenge gama, ezizizembiwa asidi kunye nesiphelo -oat. Hi xikombiso, le fomyula noshowo esters (kunye isomers metamers) ehambelana wokubala molekyuli S4N802, ngenxa nomenclatures ezahlukeneyo ezibizwa: propilformiat (propilmetanoat) izopropilformiat (izopripilmetanoat), ethyl acetate (etiletanoat) melpropionat (methylpropanoate).

Ukulungiswa esters. Ezi zinto ezisasazwa kwindalo. Ngenxa yoko, esters kobunzima ophantsi ezinto eziphilayo kunye neliphakathi asidi carboxylic series homologous yinxalenye neeoli ezixabisekileyo izityalo ezininzi (umz, uEster uksusnoizoamilovy okanye "pere Undoqo", nto leyo eyinxalenye amapere kunye nemibala ezininzi), kunye esters of glycerol kunye fatty aphezulu - iikhemikhali ngokusekelwe onke amanqatha ne-oyile. Ezinye esters zilungiselelwa izithako.

Le esterification reaction ithatha indawo yi impefumlelwano asidi carboxylic (nezimbiwa) kunye alkoholi. Lo kuvala lisebenza njenge (H2S04 ezisetyenziswa ngokuxhaphakileyo) olomeleleyo acid bezimbiwa. Kwemolekyuli ngumnxibelelanisi iyazingenela carboxylic acid.

Izinga indlela esterification kuxhomekeke kwakhona kwi ezinxulumeneyo Iqela OH (lokuqala, lesibini okanye lesithathu) nayo nayiphi na atom carbon phezu umchiza kuhlobo acid kunye notywala kunye nesakhiwo ezizizembiwa chain, nto leyo ehambisana kunye carboxyl.

Haydrolisis le esters. Indlela abasabela haydrolisis (saponification) esters - zisabela reverse esterification. Ludlula kancinci. Ukuba wandisa i umxube reaction, umxube asidi izimbiwa okanye alkalis, ukunyuka yayo uqina. saponification kwealkali ithatha indawo ngokuphindwe kaliwaka ngokukhawuleza kunokuba asidi. Le esters ke hydrolyzed ngendlela obrak medium, kunye glycol - in acid.

Phezu esters zokufudumeza kunye alkoholi phambi sulphate acid okanye alcoholates (obrak medium) alkoxy exchange kwenzeka. Oku kwenza Ester entsha, kwaye indlela medium ibuyiswa utywala, nto leyo ngaphambili ubume iintsalela kwi molecule Ester.

Esters zokunciphisa reaction. arhente Ukuncitshiswa kakhulu amaninzi Lithium hydride aluminiyam, isodiyam abilayo utywala. Esters yokumelana eliphezulu ukuya intshukumo ye iioksidenti eyahlukeneyo esetyenziswa kuyondelelaniswe okanye uhlalutyo lwekhemikhali ukukhusela amaqela utywala izakhi.

eziphambili abameli Esters. Ethyl ethanoate (kaEtere acetic) ukuba afunyenwe esterification indlela ethanol kunye acetate kuvala acid ( sulphate acid). Ethyl ethanoate isetyenziswa njenge kuphela ye neselulosi Nitrate ekuvelisweni msi wompu, kwaye negative, amacandelo essences iziqhamo kushishino kokutya.

Izoamiletanoat (kaEtere uksusnoizoamilovy, "emibhaka umongo") enyibilikayo kakhulu ethanol, diethyl kaEtere. Acetate lalungiselela esterification ye asidi kunye isoamyl utywala. Izoamilmetilbutanoat kusetyenziswa component incasa in iziqholo kwaye kuphela.

Izoamilizovaleriat ( "apile" Eneneni, iEtere izovalerianovoizoamilovy) efunyanwa ngokuhlanganisa esterification isovaleric acid kunye notywala isoamyl. Ester uthe isetyenziswa njenge essences isiqhamo yokudla.