1 Mawu Oyamba
Pakali pano, waukulu zopangira ntchito yokonzacellulose etherndi thonje, ndipo kutulutsa kwake kukutsika, ndipo mtengo ukukweranso;
Kuphatikiza apo, mankhwala omwe amagwiritsidwa ntchito kwambiri monga chloroacetic acid (poizoni kwambiri) ndi ethylene oxide (carcinogenic) nawonso amawononga kwambiri thupi la munthu komanso chilengedwe. Buku
M'mutu uno, mapaini a cellulose okhala ndi chiyero chochulukirapo kuposa 90% omwe atulutsidwa m'mutu wachiwiri amagwiritsidwa ntchito ngati zopangira, ndipo sodium chloroacetate ndi 2-chloroethanol amagwiritsidwa ntchito m'malo.
Kugwiritsa ntchito poizoni wa chloroacetic acid ngati etherifying agent, anioniccarboxymethyl cellulose (CMC), non-ionic hydroxyethyl cellulose anakonzedwa.
Cellulose (HEC) ndi hydroxyethyl carboxymethyl cellulose (HECMC) ma ether atatu a cellulose. chinthu chimodzi
Njira zokonzekera zama cellulose ethers zitatu zidakongoletsedwa ndi kuyesa ndi kuyesa kwa orthogonal, ndipo ma ether opangidwa ndi cellulose adadziwika ndi FT-IR, XRD, H-NMR, ndi zina zambiri.
Zofunikira za cellulose etherification
Mfundo ya cellulose etherification ikhoza kugawidwa m'magawo awiri. Gawo loyamba ndi njira ya alkalization, ndiye kuti, panthawi ya alkalization ya cellulose,
Omwazika mofanana mu njira ya NaOH, pine cellulose imatupa mwamphamvu chifukwa cha kugwedezeka kwamakina, komanso ndikukula kwa madzi.
Mamolekyu ang'onoang'ono a NaOH adalowa mkati mwa pine cellulose, ndipo adachita ndi magulu a hydroxyl pa mphete ya glucose structural unit,
Amapanga alkali cellulose, likulu logwira ntchito la etherification reaction.
Gawo lachiwiri ndi njira ya etherification, ndiko kuti, zomwe zimachitika pakati pa malo ogwira ntchito ndi sodium chloroacetate kapena 2-chloroethanol pansi pamikhalidwe yamchere, zomwe zimapangitsa
Pa nthawi yomweyo, etherifying wothandizira sodium chloroacetate ndi 2-chloroethanol adzatulutsanso mlingo wina wa madzi pansi pa zinthu zamchere.
Zochita zam'mbali zimathetsedwa kuti apange sodium glycolate ndi ethylene glycol, motsatana.
2 Kukhazikika kwa alkali decrystallization pretreatment of pine cellulose
Choyamba, konzani njira ina ya NaOH ndi madzi a deionized. Ndiye, pa kutentha kwina, 2g wa paini CHIKWANGWANI
Vitaminiyi imasungunuka mumtundu wina wa yankho la NaOH, lolimbikitsidwa kwa nthawi, ndiyeno limasefedwa kuti ligwiritsidwe ntchito.
Wopanga Chitsanzo cha Zida
Precision pH Meter
Wotolera mtundu wokhazikika wa kutentha kwa maginito stirrer
Vacuum kuyanika uvuni
Electronic balance
Pampu yamadzi yozungulira yamitundu yambiri
Fourier Transform Infrared Spectrometer
X-ray diffractometer
Nuclear Magnetic Resonance Spectrometer
Malingaliro a kampani Hangzhou Aolilong Instrument Co., Ltd.
Malingaliro a kampani Hangzhou Huichuang Instrument Equipment Co., Ltd.
Malingaliro a kampani Shanghai Jinghong Experimental Equipment Co., Ltd.
Malingaliro a kampani METTLER TOLEDO Instruments (Shanghai) Co., Ltd.
Malingaliro a kampani Hangzhou David Science and Education Instrument Co., Ltd.
Malingaliro a kampani American Thermo Fisher Co., Ltd.
American Thermoelectric Switzerland ARL Company
Kampani yaku Swiss BRUKER
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Kukonzekera kwa CMCs
Kugwiritsa ntchito pine nkhuni alkali mapadi pretreated ndi moyikira alkali decrystallization monga zopangira, ntchito Mowa monga zosungunulira ndi ntchito sodium chloroacetate monga etherification.
CMC yokhala ndi DS yapamwamba idakonzedwa ndikuwonjezera alkali kawiri ndi etherifying agent kawiri. Onjezerani 2g wa pine wood alkali cellulose mu botolo la makosi anayi, kenaka yikani voliyumu ina ya zosungunulira za ethanol, ndikuyambitsa bwino kwa 30min.
pafupifupi, kotero kuti mapadi alkali omwazika kwathunthu. Kenako onjezani kuchuluka kwa zinthu zamchere ndi sodium chloroacetate kuti muzichita kwakanthawi pa kutentha kwina kwa etherification.
Patapita nthawi, kuwonjezera kwachiwiri kwa alkaline wothandizira ndi sodium chloroacetate kutsatiridwa ndi etherification kwa nthawi. Zitatha, kuziziritsa ndi kuziziritsa, ndiye
Sambani ndi kuchuluka koyenera kwa glacial acetic acid, ndiye fyuluta yoyamwa, yambani ndikuwumitsa.
Kukonzekera kwa HECs
Kugwiritsa ntchito paini nkhuni alkali mapadi pretreated ndi anaikira alkali decrystallization monga zopangira, Mowa monga zosungunulira ndi 2-chloroethanol monga etherification.
HEC yokhala ndi MS yapamwamba idakonzedwa ndikuwonjezera alkali kawiri ndi etherifying agent kawiri. Onjezani 2g ya pine wood alkali cellulose mu botolo la makosi anayi, ndi kuwonjezera voliyumu ya 90% (gawo lagawo) ethanol, yambitsani.
Limbikitsani kwa nthawi kuti mubalalike kwathunthu, kenaka onjezerani kuchuluka kwa alkali, ndikuwotcha pang'onopang'ono, kuwonjezera voliyumu ina ya 2-
Chloroethanol, etherified pa kutentha zonse kwa nthawi, ndiyeno anawonjezera otsala sodium hydroxide ndi 2-chloroethanol kupitiriza etherification kwa nthawi. chithandizo
Zomwezo zikamalizidwa, sinthani ndi kuchuluka kwa glacial acetic acid, ndipo pomaliza sefa ndi fyuluta yagalasi (G3), sambani, ndikuwumitsa.
Kukonzekera kwa HEMCC
Kugwiritsa ntchito HEC yokonzedwa mu 3.2.3.4 monga zopangira, ethanol monga sing'anga, ndi sodium chloroacetate monga etherifying wothandizira kukonzekera.
Mtengo wa HECMC. Njira yeniyeni ndi: tengani kuchuluka kwa HEC, ikani mu botolo la khosi la 100 mL, kenaka yonjezerani kuchuluka kwa voliyumu.
90% Mowa, umakaniko chipwirikiti kwa nthawi kuti izo mokwanira omwazika, kuwonjezera mlingo wina wa alkali pambuyo kutentha, ndi pang'onopang'ono kuwonjezera.
Sodium chloroacetate, etherification pa kutentha kosalekeza imatha pakapita nthawi. Zomwezo zikamalizidwa, sinthani ndi glacial acetic acid kuti muchepetse, kenako gwiritsani ntchito fyuluta yagalasi (G3)
Pambuyo kuyamwa kusefera, kutsuka ndi kuyanika.
Kuyeretsa ma cellulose ethers
Pokonzekera ma cellulose ether, zinthu zina zomwe zimapangidwa nthawi zambiri zimapangidwa, makamaka mchere wa sodium chloride ndi zina.
zonyansa. Pofuna kupititsa patsogolo ubwino wa cellulose ether, kuyeretsa kosavuta kunkachitika pa cellulose ether yomwe inapezeka. chifukwa ali m'madzi
Pali kusungunuka kosiyana, kotero kuyesako kumagwiritsa ntchito gawo linalake la hydrated ethanol kuyeretsa ma etha atatu a cellulose okonzeka.
kusintha.
Ikani chitsanzo cha cellulose etha chokonzedwa ndi khalidwe linalake mu beaker, onjezerani kuchuluka kwa 80% Mowa womwe watenthedwa mpaka 60 ℃ ~ 65 ℃, ndikukhalabe oyambitsa makina pa 60 ℃ ~ 65 ℃ pa kutentha kwanthawi zonse kutentha maginito stirrer. pa 10 ℃. min. Tengani zamatsenga kuti ziume
Mu beaker yoyera, gwiritsani ntchito silver nitrate kuyang'ana ayoni a kloride. Ngati pali mphepo yoyera, sefani kudzera mu fyuluta yagalasi ndikutenga cholimba
Bwerezani masitepe am'mbuyomu a gawo la thupi, mpaka kusefa mutawonjezera dontho la 1 la yankho la AgNO3 lilibe madzi oyera, ndiko kuti, kuyeretsedwa ndi kutsuka kwatha.
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kulowa (makamaka kuchotsa zomwe zimachitika ndi NaCl). Pambuyo kuyamwa kusefera, kuyanika, kuzirala kwa firiji ndi masekeli.
misa, g.
Njira Zoyesera ndi Makhalidwe a Cellulose Ethers
Kutsimikiza kwa Degree of Substitution (DS) ndi Molar Degree of Substitution (MS)
Kutsimikiza kwa DS: Choyamba, yezani 0.2 g (yolondola mpaka 0.1 mg) ya sampuli yoyeretsedwa ndi yowuma ya cellulose ether, sungunulani mu
80mL wa madzi osungunuka, osonkhezeredwa ndi kutentha kwa madzi osamba nthawi zonse pa 30 ℃ ~ 40 ℃ kwa 10min. Kenako sinthani ndi sulfuric acid solution kapena NaOH solution
pH ya yankho mpaka pH ya yankho ndi 8. Kenako mu beaker yokhala ndi pH mita elekitirodi, gwiritsani ntchito muyezo wa sulfuric acid.
Kuti muchepetse, pansi pazovuta, yang'anani kuwerengera kwa mita ya pH pamene mukugwedeza, pamene mtengo wa pH wa yankho umasinthidwa kukhala 3.74,
Titration imatha. Onani kuchuluka kwa sulfuric acid solution yomwe imagwiritsidwa ntchito panthawiyi.
M'badwo:
Chiwerengero cha manambala apamwamba a proton ndi gulu la hydroxyethyl
Chiŵerengero cha chiwerengero cha mapulotoni apamwamba; I7 ndiye kuchuluka kwa gulu la methylene pagulu la hydroxyethyl
Kuchuluka kwa proton resonance pachimake; ndi mphamvu ya proton resonance pachimake cha magulu 5 a methine ndi gulu limodzi la methylene pa cellulose glucose unit.
Sumu.
Njira zoyesera zomwe zafotokozedwera pakuyesa mawonekedwe a infrared ma cellulose ethers CMC, HEC ndi HEECMC.
Lamulo
3.2.4.3 XRD mayeso
X-ray Diffraction Analysis Analysis Test of Characterization of Three Cellulose Ethers CMC, HEC ndi HEECMC
njira yoyesera yofotokozedwa.
3.2.4.4 Kuyesedwa kwa H-NMR
Ma spectrometer a H NMR a HEC adayezedwa ndi Avance400 H NMR spectrometer yopangidwa ndi BRUKER.
Pogwiritsa ntchito deuterated dimethyl sulfoxide monga zosungunulira, yankholo linayesedwa ndi mawonekedwe a hydrogen NMR amadzimadzi. Kuyesa pafupipafupi kunali 75.5MHz.
Kutentha, yankho ndi 0.5mL.
3.3 Zotsatira ndi Kusanthula
3.3.1 Kukhathamiritsa kwa njira yokonzekera CMC
Pogwiritsa ntchito pine cellulose yotengedwa m'mutu wachiwiri ngati zopangira, komanso kugwiritsa ntchito sodium chloroacetate monga etherifying agent, njira yoyesera chinthu chimodzi idakhazikitsidwa,
Kukonzekera kwa CMC kunakonzedwa bwino, ndipo zosinthika zoyamba za kuyesera zinayikidwa monga momwe tawonetsera mu Table 3.3. Zotsatirazi ndi ndondomeko yokonzekera HEC
Mu luso, kusanthula zinthu zosiyanasiyana.
Gulu 3.3 Zoyambira Zoyambira
Mtengo Woyamba wa Factor
Prepreatment alkalizing kutentha / ℃ 40
Prepreatment alkalizing time/h 1
Pretreatment solid-liquid ratio/(g/mL) 1:25
Pretreatment lye concentration/% 40
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Gawo loyamba etherification kutentha/℃ 45
Gawo loyamba la etherification nthawi/h 1
Gawo lachiwiri etherification kutentha/℃ 70
Gawo lachiwiri la etherification nthawi/h 1
Mlingo woyambira mu etherification stage/g 2
Kuchuluka kwa etherifying agent mu gawo la etherification/g 4.3
Etherified solid-liquid ratio/(g/mL) 1:15
3.3.1.1 Chikoka cha zinthu zosiyanasiyana pa digiri ya CMC m'malo mwa pretreatment alkalization stage
1. Zotsatira za pretreatment alkalization kutentha pa digiri m'malo CMC
Pofuna kuganizira zotsatira za kutentha kwa pretreatment alkalization pamlingo wolowa m'malo mwa CMC yomwe idalandira, pankhani ya kukonza zinthu zina monga zoyambira zoyambira,
Pansi pazimenezi, zotsatira za kutentha kwa pretreatment alkalization pa digiri ya CMC m'malo zimakambidwa, ndipo zotsatira zake zikuwonetsedwa mkuyu.
Prepreatment alkalizing kutentha / ℃
Zotsatira za pretreatment alkalizing kutentha pa CMC m'malo digiri
Zitha kuwoneka kuti kuchuluka kwa m'malo mwa CMC kumawonjezeka ndi kuwonjezeka kwa kutentha kwa pretreatment alkalization, ndi kutentha kwa alkalization ndi 30 °C.
Madigiri apamwambawa olowa m'malo amachepetsa ndi kutentha. Izi zili choncho chifukwa kutentha kwa alkalizing kumakhala kochepa kwambiri, ndipo mamolekyu sagwira ntchito ndipo sangathe
Mogwira kuwononga crystalline m'dera mapadi, zomwe zimapangitsa kuti zikhale zovuta kwa etherifying wothandizira kulowa mkati mwa mapadi mu siteji etherification, ndi mlingo anachita ndi mkulu.
otsika, kuchititsa m'munsi digiri ya mankhwala m'malo. Komabe, kutentha kwa alkalization sikuyenera kukhala kokwera kwambiri. Pamene kutentha kumawonjezeka, pansi pa kutentha kwakukulu ndi alkali wamphamvu,
Cellulose sachedwa kuwonongeka kwa okosijeni, ndi mlingo wa m'malo mankhwala CMC amachepetsa.
2. Chikoka cha pretreatment alkaliization nthawi pa CMC m'malo digiri
Pansi pa momwe kutentha kwa pretreatment alkalization ndi 30 ° C ndipo zinthu zina ndizoyambira, zotsatira za pretreatment alkalization nthawi pa CMC zimakambidwa.
Zotsatira za m'malo. Digiri ya m'malo
Prepreatment alkalizing nthawi/h
Zotsatira za pretreatment alkalinization nthawiCMCdigiri yolowa m'malo
Kuchulukirachulukira komweko kumakhala kofulumira, koma yankho la alkali limafunikira nthawi yosakanikirana mu ulusi.
Zitha kuwoneka kuti nthawi ya alkalization ndi 0.5-1.5h, kulowetsedwa kwa mankhwala kumawonjezeka ndi kuwonjezeka kwa nthawi ya alkalization.
Mlingo wa kulowetsedwa kwa mankhwala omwe anapezedwa unali wapamwamba kwambiri pamene nthawi inali 1.5h, ndipo mlingo wa kulowetsedwa unachepa ndi kuwonjezeka kwa nthawi pambuyo pa 1.5h. Izi zikhoza
Zingakhale chifukwa kumayambiriro kwa alkalization, ndi kutalika kwa nthawi ya alkalization, kulowetsedwa kwa alkali ku cellulose kumakhala kokwanira, kotero kuti CHIKWANGWANI.
Mapangidwe apamwamba amakhala omasuka, kuonjezera wothandizira etherifying ndi sing'anga yogwira ntchito
Nthawi yotumiza: Apr-26-2024