Ethers. feature

Ethers yog organic tshuaj, lub lwg me me uas muaj hydrocarbon radicals txuas mus rau cov pa atom. Cov ntaub ntawv yog raws li nram no: R'-O-R ", qhov twg R" thiab R 'yog zoo tib yam los yog sib txawv radicals.

Ethers yog ntshai li derivatives ntawm alcohols. Cov tebchaw muaj compound npe. Nws yuav siv lub title radicals (ascending molecular nyhav) thiab, nyob rau hauv qhov tseeb, lo lus "cua" (dimethyl ether SN3OSN3, methyl ethyl ether S2N5OSN3 thiab thiaj li nyob).

Symmetrical tebchaw R-O-R yog tau los ntawm intramolecular lub cev qhuav dej ntawm ib tug haus dej cawv. Nyob rau hauv ib molecule, nyob rau kev sib txuas lus tshwm sim OH kis, thiab rau lwm yam - lub C-O. Cov tshuaj tiv thaiv yuav muab suav hais tias raws li ib tug nucleophilic hloov HO-pab pawg neeg (nyob rau hauv ib tug molecule) pab pawg neeg RO (ntawm lwm molecule).

Asymmetric compound R-O-R 'tsim nyob rau hauv lub sis ntawm alkoxide thiab galogenouglevodoroda.

Ethers (tsis zoo li lawv isomeric alcohols) muaj tsawg melting thiab kub cov ntsiab lus. Nrog dej sib txuas yuav luag tsis sib tov. Qhov no yog vim lub fact tias cov ethers tsis tsim hydrogen bonds vim lub tsis tuaj kawm ntawv nyob rau hauv lub molecule ncov qaumteb qabteb O-H bonds.

Tebchaw muaj tsawg kom nquag plias. Lawv muaj ib tug tsawg dua muaj peev xwm mus teb dua alcohols.

Ethers yog feem ntau siv raws li ib tug hnyav vim hais tias ntawm lawv muaj peev xwm kom yaj ntau organic tshuaj.

Qhov tseem ceeb tshaj tebchaw xws li heterocyclic acidic tshuaj: dioxane thiab epoxide (ethylene oxide).

Tus thawj yog ib tug zoo kuab. Dioxane yog miscible nrog ob hydrocarbons thiab dej. Vim hais tias ntawm cov qualities no compound tseem hu ua "organic dej". Dioxane yog toxic, tab sis nws loj tshaj kev nyab xeeb nruab nrab yog halogen dibenzoderivatives.

cellulose esters yog cov khoom ntawm hloov chaw ntawm cov hydrogen atom nyob rau hauv lub hydroxyl pawg ntawm cellulose macromolecules yog alkyl los yog acid moieties. Lub synthesis yog nqa tawm mus impart tshiab thaj chaw ntawm ib yam khoom uas, nyob rau hauv kev lub solubility thiab thermoplasticity. Thaum pawg acid residues tsim complex, los ntawm hloov nrog alkyl radicals - yooj yim sib txuas.

Thawj npaj nyob rau hauv tus txheej txheem ntawm acylation thiab esterification - thaum reacting cellulose nrog inorganic thiab organic acids, lawv acid chlorides thiab anhydrides. Qhov loj tshaj tswv yim tseem ceeb ksatogenatam. Cov tebchaw yog npaj los ntawm reacting nrog inorganic acids thiab lawv cov kev siv nyob rau hauv qhov siv thiab ua cellophane thiab viscose fibers. Muaj tseem ceeb thiab cellulose nitrates. Lawv yog siv nyob rau hauv qhuav ntawm lacquers, films, smokeless hmoov.

Ntawm cov tebchaw tau los ntawm cov tshuaj tiv thaiv nrog organic acids, nyob rau hauv kev ua lag luam lug siv cellulose acetates. Lawv yog siv nyob rau hauv qhov kev npaj ntawm cov khoom cua fibers, yas thiab zaj duab xis.

Tseem muaj mixed cellulose esters. Lawv muaj ib tug ntau yam ntawm acyl thiab alkyl substituents.

Thaj chaw ntawm cellulose ethers nyob ntawm qhov xwm ntawm tus radical. Tus nqi thiab muaj ib tug degree ntawm hloov chaw thiab polymerization.

Tej yam yooj yim uas tsis muaj-pawg tebchaw yog soluble nyob rau hauv aqueous alkaline daws teeb meem thiab dej. Qhov no pub rau lawv siv raws li thickeners thiab stabilizers nyob rau hauv emulsions nyob rau hauv cov roj, daim ntawv, textile, khoom noj khoom haus, kws thiab lwm yam lag luam. Heev pawg esters (complex thiab yooj yim) tau tshaj plasticizers. Lawv yog siv nyob rau hauv qhov siv thiab ua yas thiab cov xim tsev tau txais.

Crown ethers yog polyesters muaj ntau oxygen nyob rau hauv lub nplhaib atoms. Technically, lawv yuav muab xam raws li cov khoom ntawm ethylene oxide tsiklooligomerizatsii. Ib cim khoom teejtug uas yog cov tebchaw yog tus muaj peev xwm mus tsim ntau ceg nrog rau ntau yam ntsev ntawm alkali hlau. Cov ceg yog tsim vim electrostatic sis raug zoo.