1.structure thiab npaj cov ntsiab cai ntawm cellulose ether
Daim duab 1 qhia cov qauv ntawm cov qauv ntawm cellulose. Txhua lub bd-anhydroglulucose chav (qhov rov qab ntsuas ntawm cellulose) hloov ib pab pawg ntawm C (2) thiab C (6) txoj haujlwm, muaj txog cov pab pawg ether. Vim yog cov ntaub pua plag hauv pob zeb thiab cuam tshuam hydrogen bonds ntawmCellulose Macromolecules, nws yog qhov nyuaj rau yaj hauv dej thiab yuav luag txhua cov kuab organic. Cov lus qhia ntawm cov pab pawg ntawm ether los ntawm etherification rhuav tshem cov intramolecular thiab intermolecular hydogen haydroity, thiab zoo heev txhim kho nws solubility hauv dej xov xwm.
Raug Eherderfiefiefiefiefed yog tsawg dua molecular hnyav alkoxy pawg neeg, uas tej zaum yuav hloov dua lwm pawg neeg xws li carboxyl, hydroxyl lossis amino pawg. Cov neeg tuaj yeem yog ib qho, ob lossis ntau hom sib txawv. Raws cellulose mactromolecular chart, cov pab pawg hydroxyl ntawm C (2), c (6) thiab C (6) Nruj me ntsis kev hais lus, cellulose ether feem ntau tsis muaj cov khoom muaj txiaj ntsig, tsuas yog hloov cov pab pawg uas tau hloov chaw). Cov khoom no tsuas siv tau rau kev kuaj sim tshuaj thiab tshawb fawb, thiab tsis muaj nqi lag luam.
(a) Tus qauv dav dav ntawm ob lub anhydoglulucose ntawm lub cellulogose ether molecular saw, R1 = H, lossis ib tus organic hloov;
(b) cov molecular saw thooj ntawm carboxymethylhydroxyethyl cellulose, cov qib degree hloov chaw ntawm Carboxymethyl yog 0.5, cov qib ntawm kev hloov ntawm hydroxyethyl yog 2.0, thiab qib degree hloov chaw ntawm tus hniav puas yog 3.0. Cov qauv no sawv cev rau nruab nrab hloov theem ntawm Ehereified pab pawg, tab sis cov neeg hloov chaw yog random.
Rau txhua tus hloov chaw, tag nrho tus nqi ntawm etherification yog qhia los ntawm cov qib DS tus nqi. Qhov ntau ntawm DS yog 0 ~ 3, uas yog sib npaug rau cov pawg nruab nrab ntawm cov pab pawg hydroxyl hloov los ntawm cov pab pawg ntawm pawg uas muaj kev cuam tshuam nrog txhua pawg.
Rau hydroxyalkyl cellulose neeg muaj kev pab hais tias yuav pib ethothyl pawg, thiab cov qib hloov tau los ntawm MS tus nqi tshiab, uas yog, cov nyiaj ntsuab los hloov. Nws sawv cev ntawm tus naj npawb nruab nrab ntawm moles ntawm lub etherplay tus neeg sawv cev reactant ntxiv rau txhua ntu ntawm ib qho kev ua haujlwm. Tus reactant yog ethylene oxide thiab cov khoom muaj cov khoom siv hydroxyethyl hloov chaw. Hauv daim duab 1, MS tus nqi ntawm cov khoom yog 3.0.
Theoretically, tsis muaj qhov txwv sab saud rau MS tus nqi. Yog tias tus nqi DS ntawm cov qib qis ntawm cov pab pawg muaj dej hiav txwv tseem ceeb Txhawm rau sawv cev rau kev hloov pauv qib thiab theem deg es tsis txhob siv DS thiab MS tseem ceeb. Qhov loj feem ntawm txhua pawg thiab nws cov DS lossis MS cov nqi tuaj yeem hloov dua los ntawm kev xam yooj yim.
Feem ntau cov cellulose muaj cov neeg hais txog dej-soluble, thiab qee tus kuj yog ib nrab soluble hauv cov kuab tshuaj muaj kuab. Cellulose ether muaj cov yam ntxwv ntawm kev ua haujlwm siab, tus nqi qis, kev ua tau yooj yim thiab muaj ntau yam thiab cov ntawv thov tau nthuav dav. Raws li tus neeg sawv cev ntawm tus neeg saib xyuas, cellulose ether muaj cov ntawv thov zoo nyob hauv ntau thaj teb kev lag luam. tuaj yeem tau txais los ntawm MS / DS.
Cellulose Cov Qauv Ua Haujlwm tau faib raws li cov qauv tshuaj ntawm cov neeg hloov chaw rau hauv kev ua haujlwm ntawm anionic, cationic thiab cov neeg tsis muaj kev ua neej. Cov neeg tsis muaj kev pab tau tuaj yeem faib ua cov dej-soluble thiab cov khoom roj-soluble.
Cov khoom lag luam uas tau muaj cov lag luam tau muaj nyob hauv lub rooj sab sauv 1. Qhov qis ib feem ntawm lub rooj 1. Tsis paub txog cov khoom lag luam tseem ceeb.
Cov ntawv xa tawm ntawm cov kab ke tuaj yeem muaj npe tuaj yeem muaj npe raws li DS (MS), rau cov tsiaj ntawv ntawm cov lus hais tseg, rau cov lus luv yog hemc, thiab nws kuj tuaj yeem sau ua MHEC rau Tshaj tawm methyl hloov.
Cov pab pawg hydroxyl ntawm cellulose tsis yooj yim los ntawm etherical cov txheej txheem, thiab lub etherification tus txheej txheem yog feem ntau yog nyob rau hauv Alkaline cov xwm txheej, feem ntau siv qee qhov kev xav ntawm Nao que queous daws. Lub cellulose yog thawj zaug ua rau hauv o ua si ntawm alkali cellulose nrog Naoh aqueous daws, thiab tom qab ntawd undergoes cov tshuaj tiv thaiv nrog tus neeg sawv cev here. Thaum muaj kev tsim khoom thiab kev tsim cov neeg ua kom sib xyaw, sib txawv ntawm cov neeg sawv cev sib xyaw, lossis cov neeg sawv cev rau tib kauj ruam los ntawm cov kauj ruam ntawm cov kauj ruam (yog tias tsim nyog). Muaj plaub yam tshuaj tiv thaiv tawm hauv lub Erictefine ntawm cellulose, uas tau hloov los ntawm cov tshuaj tiv thaiv kab mob (cellulosic yog hloov los ntawm cell-oh) raws li hauv qab no:
Kab zauv (1) piav txog Williamson Ethetification cov tshuaj tiv thaiv. Rx yog ib qho inorganic acid ester, thiab x yog halogen br, cl lossis sulfuric acid ester. Chloride R-CL feem ntau yog siv hauv kev lag luam, piv txwv li, methyl chloride, ethyl chloride lossis chloroacetic acid. Tus nqi stoichiometric ntawm lub hauv paus yog noj nyob rau hauv cov kev coj ua. Tus neeg lag luam cellulose ether cov khoom siv methyl cellulose, cov tshuaj cellulose thiab cov tshuaj tua kab mob ntawm Williamson hereification.
Cov tshuaj tiv thaiv (2) yog qhov tshuaj tiv thaiv ntawm cov epoxides (xws li r = h, ch3, lossis c2h5) thiab cov pab pawg hydroxules tsis siv lub hauv paus. Qhov kev tawm tsam no yuav txuas ntxiv rau cov pab pawg hydroxyl ntxiv rau ntawm Odigokylene ouchethyl Exide (Aziridine) yuav ua rau muaj aminethyl offe: cell-d-ch2-nh2 Cov. Cov khoom lag luam xws li hydroxyethyl cellulose, hydroxypropyl cellulose thiab hydroxybutyl cellulose yog txhua yam khoom ntawm lub hauv paus-catalalyzed epoxidation.
Cov tshuaj tiv thaiv (3) yog cov tshuaj tiv thaiv ntawm cell-oh thiab cov organic sib xyaw ua ke hauv cov pab pawg alkaline hauv nruab nrab alkaline, xws li CN, Conh2, lossis So3-nA +. Niaj hnub no cov tshuaj tiv thaiv no tsis tshua siv siv.
Cov tshuaj tiv thaiv (4), etherification nrog diazoalkane tsis tau muaj chaw lag luam tsis tau.
- Hom ntawm cov cellulose neeg muaj kev pab
Cellulose ether tuaj yeem yog monoether lossis sib xyaw ether, thiab nws cov peev xwm sib txawv. Muaj cov pab pawg hydrophilic rau ntawm cov cellulose, xws li cov khoom siv solubility, thaum lub sij hawm methyl, thiab lwm yam hloov kho siab Muab cov khoom lag luam so dej solubility, thiab cov khoom tsis muaj dej ntws tsawg hauv dej lossis tuaj yeem yaj hauv cov tshuaj alkali. Nrog rau kev tshawb nrhiav hauv qhov tob ntawm cov yam ntxwv ntawm cov neeg muaj kev pab ntawm cellulose tshiab thiab tsim tawm, thiab kev tsav tsheb loj tshaj plaws yog qhov dav thiab kev ua lag luam rov qab.
Cov kev cai lij choj dav dav ntawm cov pawg ntawm cov pab pawg hauv kev sib xyaw rau cov khoom siv solubility yog:
1) Nce cov ntsiab lus ntawm Hydrophobic pawg hauv cov khoom los nce hydrophobicity ntawm ether thiab qis dua gel point;
2) nce cov ntsiab lus ntawm pawg hydrophilic (xws li hydroxyethyl pawg) kom nce nws gel point;
3) Cov pab pawg hydroxypropyl yog tshwj xeeb, thiab kom zoo hydroxyprroperning khoom yuav qis dua, tab sis qib siab hloov yuav txo nws cov gel point; Qhov laj thawj yog vim yog tshwj xeeb cov saw hlau ntev qauv ntawm hydroxyprooration, muaj cov pab pawg hydrocules, thiab hydrophilic pawg ntawm cov ceg ntoo. Dej yog hom. Ntawm qhov tod tes, yog tias cov kev hloov pauv tau siab, yuav muaj cov ntsiab lus ntawm cov pab pawg tog, cov lus qhia hydrothobic yuav nce, thiab cov solubility yuav raug txo.
Kev tsim khoom thiab tshawb fawb txogCellulose ethermuaj keeb kwm ntev. Xyoo 1905, Suida ua ntej lub etherification ntawm cellulose, uas yog methylated nrog deegyl sulfate. Nonkyl cov kev pab tsis muaj kev pab raug cai los ntawm Lilienfeld (1912), Dresschs (1920) rau cov dej-soluble cellulose neeg muaj kev pab cuam tshuam, feem. Buchler thiab Gomberg tsim Benzyl cellulose xyoo 1921, Carboxymethyl cellulose tau ua ntej los ntawm Jansen hauv 191. Hauv 191. Txij xyoo 1937 txog rau 1938, kev lag luam ntau lawm ntawm MC thiab HEC tau pom tseeb hauv Tebchaws Meskas. Sweden pib kev tsim cov dej-soluble EHEC hauv 1945. Tom qab 1945, kev tsim cov cellulose nrawm nrawm, Tebchaws Asmeskas thiab Nyij Pooj. Thaum kawg ntawm xyoo 1957, Suav teb CMC tau muab tso rau hauv kev tsim khoom hauv Shanghai celluloid Hoobkas. Los ntawm 2004, kuv lub teb chaws muaj peev xwm ntau lawm yuav yog 30,000 tons ntawm ionic ionic ionet thiab 10,000 tons ntawm tsis-ionic ether. Los ntawm 2007, nws yuav mus txog 100,000 tons ntawm ionic ionic ionet thiab 40,000 tons ntawm kev tsis muaj ether. Cov tuam txhab siv tshuab siv lub tsev ntawm tsev thiab txawv teb chaws los yog Suav cov cellulose muaj peev xwm sib zog thiab qib kev txhim kho tas li.
Nyob rau hauv xyoo tsis ntev los no, ntau tus kws tsim kev coj noj coj ua nrog cov kev sib xyaw nrog cov txiaj ntsig sib txawv, cov vencosities, purityological tau raug tsim. At present, the focus of development in the field of cellulose ethers is to adopt advanced production technology, new preparation technology, new equipment, New products, high-quality products, and systematic products should be technically researched.
Lub Sijhawm Post: Apr-28-2024