Esters: izici jikelele kanye isicelo

Esters ka - imikhiqizo esikhundleni sama-athomu ye-hydrogen amaqembu hydroxyl of acid carboxylic futhi acid yezimbiwa at carbon olukhulu. Hlukanisa mono-, thini futhi polyesters. khona mono, acid likaNkulunkulu futhi polybasic, acid monobasic ukuze - esters okugcwele acid. Isihloko ester siqukethe igama, ezihilelekile ekwakhekeni yayo acid kanye notshwala. Ukuze esters, evame ukusetshenziswa ngesilwane esifuywayo lapha eziwubala noma zomlando. Ngokusho IUPAC amagama ngesilwane esifuywayo esters akhiwa kanje: thatha olukhulu isihloko utshwala ingezwe njengoba igama hydrocarbon acid nesiphetho -oat. Ngokwesibonelo, amafomula isakhi esters (futhi isomers metamers) elihambisana ifomula yamangqamuzana S4N802, by nomenclatures ahlukene olubizwa ngokuthi: propilformiat (propilmetanoat) izopropilformiat (izopripilmetanoat), ETHYL acetate (etiletanoat) melpropionat (methylpropanoate).

Ulungiselela esters. Lezi zinto zehlela kuthiwa esakazwa ngokwemvelo. Ngakho, esters ka ongaphakeme isisindo yamangqamuzana naphakathi acid carboxylic uchungechunge homologous bayingxenye amafutha abalulekile zezitshalo eziningi (isib ester uksusnoizoamilovy noma "ipheya essence", oyingxenye ye-amagonandoda nemibala eminingi), kanye esters ka glycerol futhi fatty acid ephakeme - chemical ngesisekelo wonke amahwahwa futhi amafutha. Ezinye esters uzilungiselele synthetically.

Ukusabela esterification kwenzeka nokuxhumana carboxylic (nokumbiwa) acid ne alcohols. I kulethe uba (H2S04 ngokuvamile ezisetshenziswa) eqinile amaminerali acid. I-molecule kulethe oyenza isebenze carboxylic acid.

Izinga ukusabela esterification kuncike futhi ku ezihambisana OH iqembu (lokuqala, lesibili noma ephakeme) nanoma iyiphi athomu carbon ku uhlobo amakhemikhali acid utshwala kanye nesakhiwo hydrocarbon chain, okuyinto lihlotshaniswa carboxyl.

Hydrolysis we esters. Ukusabela hydrolysis (saponification) esters - zisabela kanjani reverse esterification. It sihamba kancane. Uma ungeze ku ingxube yokusabela, ingxube acid yezimbiwa noma alkalis, velocity yayo iyakhula. saponification Alkali isifika ngokushesha kunokuba acid ngokuphindwe izikhathi eziyinkulungwane. I esters kuthiwa hydrolyzed i medium ane-alikhali futhi ethers - e-acid.

Lapho Ukushisa esters nge alcohols ebukhoneni sulphate acid noma alcoholates (medium ane-alikhali) alkoxy exchange kwenzeka. Lokhu yakha ester entsha, kanye medium ukusabela ebuyiselwa utshwala, elalikade kwaba ngesimo izinsalela e-molecule ester.

Esters ukunciphisa ukusabela. ejenti Ukunciphisa avame lithium aluminium hydride, sodium in abilayo utshwala. Esters of ukumelana isenzo oxidants ahlukahlukene asetshenziswa zamagama zamakhemikhali noma ukuhlaziywa ukuvikela amaqembu ezidakayo nezinto zokuhlanza phenolic.

abameleli Esters main. Ethyl ethanoate (ether acetic) is sitholwe esterification ukusabela ethanol futhi acetate acid kulethe ( sulphate acid). Ethyl ethanoate isetshenziswa njengophawu kuphela of cellulose nitrate ekukhiqizeni ongenantuthu neziqhumane, futhi ama-negative, izithelo Uketshezi izingxenye embonini yezokudla.

Izoamiletanoat (ether uksusnoizoamilovy, "ipheya essence") kuyinto kakhulu oncibilikayo Ethanol, diethyl ether. Acetate lalungiselela esterification of acid kanye isoamyl utshwala. Izoamilmetilbutanoat esetshenziswa njengoba isakhi ukunambitheka e kwamakha kanye kuphela.

Izoamilizovaleriat ( "apula" Okusho ukuthi, elithi ether izovalerianovoizoamilovy) is etholwe ukusabela le esterification isovaleric acid kanye notshwala isoamyl. ester wathi isetshenziswa njengophawu Uketshezi izithelo embonini yezokudla.