1 Chiyambi
Pakadali pano, zinthu zazikulu zomwe zimagwiritsidwa ntchito pokonzekeraether ya cellulosendi thonje, ndipo zokolola zake zikuchepa, ndipo mtengo wake ukukweranso;
Komanso, zinthu zotenthetsa thupi zomwe zimagwiritsidwa ntchito kwambiri monga chloroacetic acid (yoopsa kwambiri) ndi ethylene oxide (yomwe imayambitsa khansa) nazonso zimawononga thupi la munthu komanso chilengedwe.
Mu chaputala chino, cellulose ya paini yokhala ndi chiyero choposa 90% yochokera mu chaputala chachiwiri imagwiritsidwa ntchito ngati zopangira, ndipo sodium chloroacetate ndi 2-chloroethanol zimagwiritsidwa ntchito ngati zolowa m'malo.
Kugwiritsa ntchito chloroacetic acid yoopsa kwambiri ngati chothandizira kuchiritsa, anioniccarboxymethyl cellulose (CMC), non-ionic hydroxyethyl cellulose inakonzedwa.
Cellulose (HEC) ndi mixed hydroxyethyl carboxymethyl cellulose (HECMC) ma ether atatu a cellulose. single factor
Njira zokonzekera ma ether atatu a cellulose zinakonzedwa bwino pogwiritsa ntchito zoyeserera ndi zoyeserera za orthogonal, ndipo ma ether a cellulose opangidwa anali ndi FT-IR, XRD, H-NMR, ndi zina zotero.
Zofunikira pa etherification ya cellulose
Mfundo ya etherification ya cellulose ikhoza kugawidwa m'magawo awiri. Gawo loyamba ndi njira ya alkalization, ndiko kuti, panthawi ya alkalization ya cellulose,
Mukasakaniza mofanana mu yankho la NaOH, cellulose ya paini imatupa mwamphamvu ikagwiritsidwa ntchito ndi makina osakaniza, komanso madzi akamakula.
Mamolekyu ang'onoang'ono ambiri a NaOH adalowa mkati mwa cellulose ya paini, ndipo adagwirizana ndi magulu a hydroxyl pa mphete ya unit ya glucose structural,
Amapanga alkali cellulose, yomwe ndi malo ogwirira ntchito a etherification reaction.
Gawo lachiwiri ndi njira yopangira etherification, ndiko kuti, momwe zinthu zimachitikira pakati pa malo ogwirira ntchito ndi sodium chloroacetate kapena 2-chloroethanol pansi pa mikhalidwe ya alkaline, zomwe zimapangitsa kuti
Nthawi yomweyo, sodium chloroacetate ndi 2-chloroethanol zomwe zimapangitsa kuti madzi azituluka zimatulukanso pang'ono m'malo okhala ndi alkaline.
Zotsatira zoyipa zimatheka kupanga sodium glycolate ndi ethylene glycol, motsatana.
2 Kuchiza koyambirira kwa paini cellulose pogwiritsa ntchito alkali decrystallization
Choyamba, konzani kuchuluka kwa NaOH ndi madzi osasungunuka. Kenako, pa kutentha kwina, 2g ya ulusi wa paini
Vitaminiyo imasungunuka mu kuchuluka kwina kwa yankho la NaOH, kusunthidwa kwa kanthawi, kenako nkusefedwa kuti igwiritsidwe ntchito.
Wopanga Chitsanzo cha Zida
Chiyeso cha pH cholondola
Chosonkhetsa chotenthetsera maginito chokhazikika kutentha
Uvuni wowumitsira wa vacuum
Kusunga zamagetsi
Pumpu yozungulira madzi yopangira zinthu zambiri
Spectrometer ya Fourier Transform Infrared
Diffractometer ya X-ray
Spektromita ya Maginito a Nyukiliya
Hangzhou Aolilong Instrument Co., Ltd.
Hangzhou Huichuang Instrument Equipment Co., Ltd.
Shanghai Jinghong Experimental Equipment Co., Ltd.
METTLER TOLEDO Instruments (Shanghai) Co., Ltd.
Hangzhou David Science and Education Instrument Co., Ltd.
American Thermo Fisher Co., Ltd.
Kampani ya American Thermoelectric Switzerland ARL
Kampani yaku Switzerland ya BRUKER
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Kukonzekera kwa CMCs
Kugwiritsa ntchito alkali cellulose ya paini yokonzedwa kale ndi alkali decrystallization ngati zopangira, kugwiritsa ntchito ethanol ngati zosungunulira ndi kugwiritsa ntchito sodium chloroacetate ngati etherification
CMC yokhala ndi DS yapamwamba idakonzedwa powonjezera alkali kawiri ndi chinthu chotenthetsera kawiri. Onjezani 2g ya alkali cellulose ya pine wood mu botolo lokhala ndi khosi zinayi, kenako onjezerani voliyumu ina ya ethanol solvent, ndikusakaniza bwino kwa mphindi 30.
kuti alkali cellulose imwazike mokwanira. Kenako onjezerani kuchuluka kwa alkali agent ndi sodium chloroacetate kuti muchitepo kanthu kwa nthawi inayake pa kutentha kwina kwa etherification.
Pambuyo pa nthawi, kuwonjezeranso kachiwiri alkaline agent ndi sodium chloroacetate kenako ndi etherification kwa kanthawi. Pambuyo poti yankho latha, dzizireni kenako dzizireni, kenako
Sakanizani ndi asidi wokwanira wa glacial acetic acid, kenako sakanizani fyuluta, sambitsani ndi kuumitsa.
Kukonzekera kwa HECs
Kugwiritsa ntchito matabwa a paini alkali cellulose yokonzedwa kale ndi alkali decrystallization ngati zopangira, ethanol ngati solvent ndi 2-chloroethanol ngati etherification
HEC yokhala ndi MS yapamwamba idakonzedwa powonjezera alkali kawiri ndi chinthu chotenthetsera kawiri. Onjezani 2g ya alkali cellulose ya paini mu botolo lokhala ndi khosi zinayi, ndikuwonjezera voliyumu inayake ya 90% (voliyumu fraction), sakanizani.
Sakanizani kwa kanthawi kuti mufalikire mokwanira, kenako onjezerani kuchuluka kwa alkali, ndipo pang'onopang'ono mutenthe, onjezerani kuchuluka kwa 2-
Chloroethanol, yotenthedwa ndi kutentha kosasinthasintha kwa kanthawi, kenako inawonjezera sodium hydroxide yotsala ndi 2-chloroethanol kuti ipitirize kutentha kwa kanthawi.
Pambuyo poti yankho latha, chepetsani ndi kuchuluka kwa acetic acid, kenako sefani ndi fyuluta yagalasi (G3), sambitsani, ndipo muumitse.
Kukonzekera kwa HEMCC
Kugwiritsa ntchito HEC yokonzedwa mu 3.2.3.4 ngati zopangira, ethanol ngati njira yochitira zinthu, ndi sodium chloroacetate ngati chothandizira kutentha kuti mukonzekere
HECMC. Njira yeniyeni ndi iyi: tengani HEC yochuluka, muyiike mu botolo la 100 mL lokhala ndi khosi zinayi, kenako onjezerani kuchuluka kwake.
90% ethanol, sakanizani ndi makina kwa kanthawi kuti imwazike bwino, onjezerani kuchuluka kwa alkali mukatentha, kenako onjezerani pang'onopang'ono.
Sodium chloroacetate, etherification pa kutentha kosasintha imatha pakapita nthawi. Pambuyo poti yankho latha, lichotseni ndi glacial acetic acid kuti lichotsedwe, kenako gwiritsani ntchito glass filter (G3)
Mukamaliza kusefa, kutsuka ndi kuumitsa.
Kuyeretsa kwa ethers a cellulose
Mu ndondomeko yokonzekera ether ya cellulose, zinthu zina zomwe zimapangidwa nthawi zambiri, makamaka mchere wosapangidwa ndi sodium chloride ndi zina.
Zonyansa. Pofuna kukweza ubwino wa etha ya cellulose, kuyeretsedwa kosavuta kunachitika pa etha ya cellulose yomwe yapezeka. chifukwa ili m'madzi.
Pali kusungunuka kosiyanasiyana, kotero kuyeseraku kumagwiritsa ntchito gawo linalake la ethanol yosungunuka kuti itsuke ma ether atatu okonzedwa a cellulose.
kusintha.
Ikani chitsanzo cha ether cha cellulose chokonzedwa ndi khalidwe linalake mu beaker, onjezerani kuchuluka kwa 80% ethanol yomwe yatenthedwa kufika pa 60 ℃ ~ 65 ℃, ndipo pitirizani kusakaniza makina pa 60 ℃ ~ 65 ℃ pa chosakaniza chamagetsi chotenthetsera kutentha kosalekeza kwa 10 ℃. Mphindi. Tengani supernatant kuti iume.
Mu beaker yoyera, gwiritsani ntchito silver nitrate kuti muwone ngati pali ma chloride ions. Ngati pali white precipitate, yesefani kudzera mu fyuluta yagalasi ndipo tengani chitsulo cholimbacho
Bwerezani njira zomwe zidachitika kale pa gawo la thupi, mpaka chosefera chitatha kuwonjezera dontho limodzi la yankho la AgNO3 chisakhale ndi mpweya woyera, ndiko kuti, kuyeretsa ndi kutsuka kwatha.
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mu (makamaka kuchotsa NaCl yomwe yachokera ku chinthucho). Mukamaliza kusefa, kuumitsa, kuziziritsa kutentha kwa chipinda ndikulemera.
kulemera, g.
Njira Zoyesera ndi Kufotokozera Ma Cellulose Ethers
Kutsimikiza kwa Degree of Substitution (DS) ndi Molar Degree of Substitution (MS)
Kutsimikiza kwa DS: Choyamba, yesani 0.2 g (yolondola mpaka 0.1 mg) ya chitsanzo cha ether choyeretsedwa ndi chouma cha cellulose, chisungunuleni mu
80ml ya madzi osungunuka, osakaniza mu bafa la madzi otentha nthawi zonse pa 30℃ ~ 40℃ kwa mphindi 10. Kenako sinthani ndi yankho la sulfuric acid kapena yankho la NaOH
pH ya yankho mpaka pH ya yankho ifike 8. Kenako mu beaker yokhala ndi electrode ya pH meter, gwiritsani ntchito yankho lokhazikika la sulfuric acid
Kuti muchepetse titration, pansi pa mikhalidwe yogwedeza, yang'anani kuwerenga kwa pH meter pamene mukusintha titration, pamene pH ya yankho ikusinthidwa kufika pa 3.74,
Kuchuluka kwa titration kumatha. Onani kuchuluka kwa sulfuric acid standard solution yomwe imagwiritsidwa ntchito panthawiyi.
Mbadwo:
Chiwerengero cha manambala apamwamba a proton ndi gulu la hydroxyethyl
Chiŵerengero cha chiwerengero cha ma protoni apamwamba; I7 ndi kulemera kwa gulu la methylene pa gulu la hydroxyethyl
Mphamvu ya proton resonance peak; ndi mphamvu ya proton resonance peak ya magulu 5 a methine ndi gulu limodzi la methylene pa unit ya glucose ya cellulose
Chiwerengero.
Njira zoyesera zomwe zafotokozedwa poyesa mawonekedwe a infrared a ma ether atatu a cellulose CMC, HEC ndi HEECMC
Lamulo
3.2.4.3 Mayeso a XRD
Mayeso a X-ray Diffraction Analysis Characterization Test of Three Cellulose Ethers CMC, HEC ndi HEECMC
njira yoyesera yomwe yafotokozedwa.
3.2.4.4 Kuyesedwa kwa H-NMR
Masekondi a H NMR a HEC adayesedwa ndi masekondi a Avance400 H NMR opangidwa ndi BRUKER.
Pogwiritsa ntchito deuterated dimethyl sulfoxide ngati solvent, yankholo linayesedwa ndi liquid hydrogen NMR spectroscopy. Mafupipafupi a mayeso anali 75.5MHz.
Kutentha, yankho ndi 0.5mL.
3.3 Zotsatira ndi Kusanthula
3.3.1 Kukonza bwino njira yokonzekera CMC
Pogwiritsa ntchito cellulose ya paini yotengedwa m'mutu wachiwiri ngati zopangira, komanso pogwiritsa ntchito sodium chloroacetate ngati wothandizira kutentha, njira yoyesera chinthu chimodzi idagwiritsidwa ntchito,
Njira yokonzekera CMC idakonzedwa bwino, ndipo zosintha zoyambirira za kuyesera zidakhazikitsidwa monga momwe zasonyezedwera mu Table 3.3. Izi ndi njira yokonzekera HEC.
Mu zaluso, kusanthula zinthu zosiyanasiyana.
Gome 3.3 Makhalidwe Oyambirira a Zinthu
Mtengo woyambira wa Factor
Kutentha kokonzekera kwa alkalizing/℃ 40
Nthawi yokonzekera alkalizing pasadakhale/h 1
Chiŵerengero cha madzi olimba/(g/mL) chisanaperekedwe pasadakhale 1:25
Kuchuluka kwa lye musanalandire chithandizo/% 40
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Gawo loyamba kutentha kwa etherification/℃ 45
Nthawi yoyamba ya etherification/h 1
Gawo lachiwiri la kutentha kwa etherification/℃ 70
Nthawi yachiwiri ya etherification/h 1
Mlingo woyambira mu gawo la etherification/g 2
Kuchuluka kwa mankhwala ophera tizilombo toyambitsa matenda mu gawo la etherification/g 4.3
Chiŵerengero cha madzi olimba ndi okhazikika (etherified solid-liquid ratio/(g/mL) 1:15
3.3.1.1 Mphamvu ya zinthu zosiyanasiyana pa digiri ya kusintha kwa CMC mu gawo la alkalization isanayambe chithandizo
1. Zotsatira za kutentha kwa alkalization pa mlingo wosinthira wa CMC
Pofuna kuganizira momwe kutentha kwa alkalization kusanachitike chithandizo kumakhudzira kuchuluka kwa kusintha kwa CMC komwe kwapezeka, pankhani yokhazikitsa zinthu zina ngati mfundo zoyambira,
Pansi pa mikhalidweyi, zotsatira za kutentha kwa alkalization pa CMC substitution degree zikukambidwa, ndipo zotsatira zake zikuwonetsedwa mu Chithunzi 1.
Kutentha kokonzekera kwa alkalizing/℃
Zotsatira za kutentha kwa alkalizing pretreatment pa digiri ya CMC m'malo
Zikuoneka kuti kuchuluka kwa CMC m'malo mwake kumawonjezeka ndi kuwonjezeka kwa kutentha kwa alkalization musanayambe chithandizo, ndipo kutentha kwa alkalization ndi 30 °C.
Madigiri osinthira omwe ali pamwambapa amachepa ndi kutentha komwe kukukwera. Izi zili choncho chifukwa kutentha kwa alkalizing kumakhala kotsika kwambiri, ndipo mamolekyu sagwira ntchito mokwanira ndipo sangathe kuchita izi.
Wononga bwino dera la kristalo la cellulose, zomwe zimapangitsa kuti zikhale zovuta kuti wothandizira kutentha alowe mkati mwa cellulose panthawi ya etherification, ndipo kuchuluka kwa zomwe zimachitika kumakhala kwakukulu.
otsika, zomwe zimapangitsa kuti kusintha kwa zinthu kukhale kochepa. Komabe, kutentha kwa alkali sikuyenera kukhala kokwera kwambiri. Pamene kutentha kukukwera, chifukwa cha kutentha kwambiri komanso alkali wamphamvu,
Cellulose imakonda kuwonongeka ndi okosijeni, ndipo kuchuluka kwa CMC m'malo mwa chinthucho kumachepa.
2. Mphamvu ya nthawi yokonzekera alkaline pa digiri ya CMC yosinthira
Ngati kutentha kwa alkalization isanayambe chithandizo ndi 30 °C ndipo zinthu zina ndizo zimayambira, zotsatira za nthawi ya alkalization isanayambe chithandizo pa CMC zikukambidwa.
Zotsatira za kusintha. Mlingo wa kusintha
Nthawi yokonzekera alkalizing pasadakhale/h
Zotsatira za nthawi yokonzekera alkaline pa chithandizo cha pretreatmentCMCdigiri yosinthira
Njira yowonjezerera yokha imakhala yofulumira, koma yankho la alkali limafuna nthawi inayake yofalikira mu ulusi.
Zitha kuoneka kuti nthawi ya alkalization ikakhala maola 0.5-1.5, kuchuluka kwa zinthu zomwe zimasinthidwa kumawonjezeka ndi kuchuluka kwa nthawi ya alkalization.
Mlingo wosinthira chinthu chomwe chinapezeka unali wapamwamba kwambiri pamene nthawi inali 1.5h, ndipo mlingo wosinthira unachepa ndi kuwonjezeka kwa nthawi pambuyo pa 1.5h. Izi zitha
Zingakhale chifukwa chakuti kumayambiriro kwa alkalization, ndi nthawi yowonjezera alkalization, kulowa kwa alkali kupita ku cellulose kumakhala kokwanira, kotero kuti ulusi
Kapangidwe kake kamakhala komasuka kwambiri, zomwe zimapangitsa kuti mankhwala ophera tizilombo toyambitsa matenda komanso zinthu zogwira ntchito ziwonjezere mphamvu.
Nthawi yotumizira: Epulo-26-2024