1.Structure uye kugadzirira nheyo ye cellulose ether
Mufananidzo 1 unoratidza chimiro chakajairika che cellulose ethers. Imwe neimwe bD-anhydroglucose unit (iyo inodzokorora unit ye cellulose) inotsiva rimwe boka pane C (2), C (3) uye C (6) zvinzvimbo, ndiko kuti, panogona kuva nemapoka matatu ether. Nekuda kweiyo intra-chain uye inter-cheni hydrogen zvisungo zvecellulose macromolecules, zvakaoma kunyungudika mumvura uye zvinenge zvese organic solvents. Kuiswa kwemapoka ether kuburikidza ne etherification kunoparadza intramolecular uye intermolecular hydrogen bonds, inovandudza hydrophilicity yayo, uye inovandudza zvikuru kunyungudika kwayo mumvura.
Typical etherified substituents akaderera molecular weight alkoxy groups (1 kusvika 4 carbon atoms) kana hydroxyalkyl mapoka, anogona kuzotsiviwa nemamwe mapoka anoshanda senge carboxyl, hydroxyl kana amino mapoka. Zvinotsiva zvinogona kuva zvemhando imwe, mbiri kana kupfuura dzakasiyana. Pamwe chete necellulose macromolecular chain, mapoka ehydroxyl ari paC (2), C (3) uye C (6) nzvimbo dzega yega glucose unit anotsiviwa muzvikamu zvakasiyana. Kunyatsotaura, cellulose ether kazhinji haina chimiro chakajeka chemakemikari, kunze kweiyo zvigadzirwa zvinotsiviwa zvachose nemhando yeboka (ese matatu mapoka ehydroxyl anotsiviwa). Zvigadzirwa izvi zvinogona kungoshandiswa pakuongorora marabhoritari nekutsvaga, uye hazvina kukosha kwekutengesa.
(a) Chimiro chezvikamu zviviri zveanhydroglucose zve cellulose ether molecular chain, R1 ~ R6 = H, kana organic substituent;
(b) A molecular chain fragment ye carboxymethylhydroxyethyl cellulose, dhigirii rekutsiva carboxymethyl i0.5, dhigirii rekutsinhanisa hydroxyethyl i2.0, uye dhigirii rekutsiva molar i3.0. Chimiro ichi chinomiririra avhareji yekutsiva nhanho yemapoka etherified, asi zvinotsiva ndezvemazvo.
Kune yega yega inotsiva, huwandu hwese hweetherification hunoratidzwa nechiyero chekutsiva DS kukosha. Huwandu hweDS i0 ~ 3, iyo yakaenzana neavhareji nhamba yemapoka ehydroxyl anotsiviwa nemapoka etherification pane yega yega anhydroglucose unit.
Kune hydroxyalkyl cellulose ethers, iyo inotsiva inozotanga etherification kubva kune matsva emahara hydroxyl mapoka, uye dhigirii rekutsiva rinogona kuverengerwa neMS kukosha, ndiko kuti, iyo molar degree yekutsiva. Inomiririra avhareji yenhamba yemamoles eetherifying agent reactant yakawedzerwa kune yega anhydroglucose unit. Yakajairika reactant ndeye ethylene oxide uye chigadzirwa chine hydroxyethyl inotsiva. Mumufananidzo 1, kukosha kweMS kwechigadzirwa ndeye 3.0.
Theoretically, hapana muganho wepamusoro weiyo MS kukosha. Kana kukosha kweDS kwedhigirii rekutsiva paboka rega rega remhete yeglucose ichizivikanwa, avhareji urefu hwetani ye ether side cheniVamwe vagadziri vanowanzo shandisa chikamu chikuru (wt%) chemapoka akasiyana etherification (akadai se -OCH3 kana -OC2H4OH) kumiririra danho rekutsiva uye dhigirii panzvimbo yeDS uye MS maitiro. Chikamu chehuwandu hweboka rega rega uye kukosha kwayo kweDS kana MS kunogona kushandurwa nekuverenga kuri nyore.
Mazhinji cellulose ethers mapolymer anonyungudika nemvura, uye mamwe anonyungudika muchikamu chezvinonyungudutsa. Cellulose ether ine hunhu hwepamusoro-soro, mutengo wakaderera, kugadzirwa nyore, kuderera kwehuturu uye kwakasiyana-siyana, uye kudiwa uye minda yekushandisa ichiri kuwedzera. Semubatsiri anobatsira, cellulose ether ine mukana mukuru wekushandisa munzvimbo dzakasiyana dzeindasitiri. inogona kuwanikwa neMS/DS.
Cellulose ethers inokamurwa zvichienderana nechimiro chemakemikari ezvinotsiva kuita anionic, cationic uye nonionic ethers. Nonionic ethers inogona kukamurwa kuita zvigadzirwa zvinonyungudika mumvura uye nemafuta.
Zvigadzirwa zvakave neindasitiri zvakanyorwa muchikamu chepamusoro cheTafura 1. Chikamu chepasi cheTafura 1 chinonyora mamwe mapoka anozivikanwa etherification, ayo asati ave zvigadzirwa zvakakosha zvekutengesa.
Kurongeka kweiyo yakasanganiswa ether substituents inogona kudanwa maererano nearufabheti kurongeka kana chiyero cheiyo DS (MS), semuenzaniso, ye2-hydroxyethyl methylcellulose, pfupiso iHEMC, uye inogona zvakare kunyorwa seMHEC ku. simbisa iyo methyl inotsiva.
Mapoka ehydroxyl ari pa cellulose haasvikike zviri nyore ne etherification agents, uye etherification process inowanzoitwa pasi pemamiriro ealkaline, kazhinji achishandisa imwe concentration yeNaOH aqueous solution. Iyo cellulose inotanga kuumbwa kuita yakazvimba alkali cellulose ine NaOH aqueous solution, yozoitwa etherification reaction ne etherification agent. Munguva yekugadzirwa uye kugadzirira kwema ether akasanganiswa, marudzi akasiyana eetherification agents anofanirwa kushandiswa panguva imwe chete, kana kuti etherification inofanira kuitwa nhanho nhanho nekudyisa kwepakati (kana zvichidikanwa). Kune mana maitiro ekuita mu etherification ye cellulose, iyo inopfupikiswa nemaitiro ekuita (cellulosic inotsiviwa neCell-OH) sezvinotevera:
Equation (1) inotsanangura maitiro eWilliamson etherification. RX is anorganic acid ester, uye X ihalogen Br, Cl kana sulfuric acid ester. Chloride R-Cl inowanzoshandiswa muindasitiri, semuenzaniso, methyl chloride, ethyl chloride kana chloroacetic acid. A stoichiometric huwandu hwehwaro hunopedzwa mukuita kwakadaro. Iyo yakagadziridzwa cellulose ether zvigadzirwa methyl cellulose, ethyl cellulose uye carboxymethyl cellulose zvigadzirwa zveWilliamson etherification reaction.
Reaction formula (2) ndiyo maitikiro ekuwedzera kwebase-catalyzed epoxides (seR=H, CH3, kana C2H5) nemapoka ehydroxyl pamamorekuru ecellulose asingadyi base. Izvi zvingangoramba zvichienderera mberi sezvo mapoka matsva ehydroxyl anogadzirwa panguva yekuita, zvichiita kuti pave nekuumbwa kwe oligoalkylethylene oxide side maketani: Kufanana kwakafanana ne 1-aziridine (aziridine) ichaita aminoethyl ether: Cell-O-CH2-CH2-NH2 . Zvigadzirwa zvakaita sehydroxyethyl cellulose, hydroxypropyl cellulose uye hydroxybutyl cellulose zvese zvigadzirwa zve base-catalyzed epoxidation.
Reaction formula (3) maitiro ekuita pakati peSero-OH nemakomisheni eorganic ane anoshanda maviri ma bond mu alkaline medium, Y iboka rinobvisa maelectron, rakaita se CN, CONH2, kana SO3-Na+. Nhasi rudzi urwu rwekuita haruwanzoshandiswa mumaindasitiri.
Reaction formula (4), etherification ine diazoalkane haisati yagadzirwa.
- Mhando dze cellulose ethers
Cellulose ether inogona kuva monoether kana yakasanganiswa ether, uye maitiro ayo akasiyana. Kune yakaderera-inotsiva hydrophilic mapoka pa cellulose macromolecule, senge hydroxyethyl mapoka, ayo anogona kupa chigadzirwa neimwe dhigirii yekunyungudika kwemvura, nepo kumapoka ehydrophobic, akadai semethyl, ethyl, nezvimwewo, kungotsiva zvine mwero High degree inogona. ipa chigadzirwa kumwe kunyungudika kwemvura, uye iyo yakaderera-inotsiva chigadzirwa inongozvimba mumvura kana inogona kunyungudika mu dilute alkali solution. Nekutsvagisa kwakadzama pamusoro pezvivakwa zve cellulose ethers, itsva cellulose ethers nenzvimbo dzadzo dzekushandisa dzicharamba dzichigadzirwa uye kugadzirwa, uye simba guru rekutyaira ndiro musika wakafara uye unoramba uchinatswa.
Mutemo mukuru wekupesvedzera kwemapoka mumisanganiswa ether pane solubility properties ndeiyi:
1) Wedzera zviri mukati memapoka e-hydrophobic muchigadzirwa kuti uwedzere hydrophobicity ye ether uye kuderedza gel point;
2) Wedzera zviri mukati me hydrophilic mapoka (akadai sema hydroxyethyl mapoka) kuti awedzere iyo gel point;
3) Iro hydroxypropyl boka rinokosha, uye hydroxypropylation yakakodzera inogona kuderedza kutonhora kwegel kwechigadzirwa, uye kutonhora kwejeri kwepakati hydroxypropylated chigadzirwa chichamuka zvakare, asi nzvimbo yakakwirira yekutsiva ichaderedza gel yayo; Icho chikonzero chiri nekuda kweiyo yakakosha kabhoni ketani kureba chimiro cheboka rehydroxypropyl, yakaderera-level hydroxypropylation, isina simba mabhondi ehydrogen mukati uye pakati pemamorekuru mu cellulose macromolecule, uye hydrophilic hydroxyl mapoka pamaketani ebazi. Mvura inotonga. Kune rumwe rutivi, kana kutsiva kwakakwirira, pachava nepolymerization padivi reboka, hukama hwehuwandu hweboka re hydroxyl huchaderera, hydrophobicity ichawedzera, uye solubility ichaderedzwa panzvimbo.
Kugadzirwa uye kutsvagisa kwecellulose etherine nhoroondo refu. Muna 1905, Suida akatanga kutaura etherification ye cellulose, iyo yaive methylated ne dimethyl sulfate. Nonionic alkyl ethers aive patented naLilienfeld (1912), Dreyfus (1914) uye Leuchs (1920) yemvura-inonyungudika kana mafuta-inonyungudika cellulose ethers, zvichiteerana. Buchler naGomberg vakagadzira benzyl cellulose muna 1921, carboxymethyl cellulose yakatanga kugadzirwa naJansen muna 1918, uye Hubert akagadzira hydroxyethyl cellulose muna 1920. Mukutanga kwema1920, carboxymethylcellulose yakatengeswa muGermany. Kubva 1937 kusvika 1938, kugadzirwa kwemaindasitiri kweMC neHEC kwakaitika muUnited States. Sweden yakatanga kugadzirwa kweEHEC inonyungudika mumvura muna 1945. Mushure me1945, kugadzirwa kwe cellulose ether kwakawedzera nekukurumidza muWestern Europe, United States neJapan. Pakupera kwa1957, China CMC yakatanga kuiswa mukugadzirwa muShanghai Celluloid Factory. Pakazosvika gore ra2004, nyika yangu inokwanisa kugadzira matani 30 000 eionic ether uye 10,000 matani e-non-ionic ether. Panosvika 2007, ichasvika 100,000 matani eionic ether uye 40,000 matani eNonionic ether. Joint tekinoroji makambani kumba nekune dzimwe nyika zvakare anogara achibuda, uye China's cellulose ether kugadzirwa kwesimba uye tekinoroji level iri kuramba ichivandudza.
Mumakore achangopfuura, akawanda cellulose monoethers uye yakasanganiswa ether ane akasiyana DS kukosha, viscosities, kuchena uye rheological zvimiro zvakaramba zvichigadzirwa. Parizvino, chinangwa chebudiriro mumunda we cellulose ethers ndechekutora tekinoroji yekugadzira yepamberi, tekinoroji nyowani yekugadzirira, michina mitsva, Zvigadzirwa zvitsva, zvigadzirwa zvemhando yepamusoro, uye zvigadzirwa zvakarongeka zvinofanirwa kuongororwa nehunyanzvi.
Nguva yekutumira: Kubvumbi-28-2024