1 Isingeniso
Njengamanje, impahla eluhlaza esetshenziswa ekulungiselelenii-cellulose etherukotini, futhi umkhiqizo wawo uyancipha, futhi intengo nayo iyakhuphuka;
Ngaphezu kwalokho, ama-etherifying agents avame ukusetshenziswa njenge-chloroacetic acid (enobuthi kakhulu) ne-ethylene oxide (carcinogenic) nawo ayingozi kakhulu emzimbeni womuntu nasendaweni ezungezile. Bhukha
Kulesi sahluko, i-pine cellulose enobumsulwa obuhlobene obungaphezu kuka-90% ekhishwe esahlukweni sesibili isetshenziswa njengempahla eluhlaza, futhi i-sodium chloroacetate kanye ne-2-chloroethanol isetshenziswa njengezinye.
Ukusebenzisa i-chloroacetic acid enobuthi kakhulu njenge-etherifying, i-anionicI-carboxymethyl cellulose (CMC), i-non-ionic hydroxyethyl cellulose yalungiswa.
I-Cellulose (HEC) ne-hydroxyethyl carboxymethyl cellulose (HECMC) ama-cellulose ethers amathathu. isici esisodwa
Amasu okulungisa ama-cellulose ether amathathu athuthukiswa ngokusebenzisa izivivinyo nokuhlolwa kwe-orthogonal, futhi ama-cellulose ether ahlanganisiwe aye abonakala nge-FT-IR, XRD, H-NMR, njll.
Izisekelo ze-cellulose etherification
Umgomo we-cellulose etherification ungahlukaniswa izingxenye ezimbili. Ingxenye yokuqala yinqubo ye-alkalization, okungukuthi, ngesikhathi sokusabela kwe-alkalization ye-cellulose,
Ihlakazeke ngokulinganayo kusisombululo se-NaOH, i-pine cellulose ivuvukala ngamandla ngaphansi kwesenzo sokunyakaziswa komshini, kanye nokwandiswa kwamanzi.
Inani elikhulu lama-molecule amancane e-NaOH angena ngaphakathi kuphayini cellulose, futhi asabelana namaqembu e-hydroxyl eringini yeyunithi yesakhiwo se-glucose,
Ikhiqiza i-alkali cellulose, isikhungo esisebenzayo sokusabela kwe-etherification.
Ingxenye yesibili inqubo ye-etherification, okungukuthi, ukusabela phakathi kwesikhungo esisebenzayo ne-sodium chloroacetate noma i-2-chloroethanol ngaphansi kwezimo ze-alkali, okuholela ekutheni
Ngesikhathi esifanayo, i-etherifying agent sodium chloroacetate kanye ne-2-chloroethanol izophinde ikhiqize izinga elithile lamanzi ngaphansi kwezimo ze-alkaline.
Ukusabela okusemaceleni kuxazululwa ukukhiqiza i-sodium glycolate ne-ethylene glycol, ngokulandelana.
2 I-alkali decrystallization egxilisiwe pretreatment kaphayini cellulose
Okokuqala, lungiselela ukuhlushwa okuthile kwesisombululo se-NaOH ngamanzi angcolile. Khona-ke, ekushiseni okuthile, i-2g ye-pine fiber
Ivithamini ichithwa kumthamo othile wesisombululo se-NaOH, inyakaziswa isikhathi esithile, bese ihlungwa ukuze isetshenziswe.
Umkhiqizi Wemodeli Yezinsimbi
Ukunemba pH Imitha
Uhlobo lomqongeleli wokushisa okungaguquguquki kwe-stirrer kazibuthe
Vacuum ihhavini yokomisa
Ibhalansi ye-elekthronikhi
Uhlobo lwamanzi olujikelezayo lwephampu ye-vacuum enezinjongo eziningi
I-Fourier Transform Infrared Spectrometer
I-X-ray diffractometer
I-nuclear Magnetic Resonance Spectrometer
I-Hangzhou Aolilong Instrument Co., Ltd.
I-Hangzhou Huichuang Instrument Equipment Co., Ltd.
I-Shanghai Jinghong Experimental Equipment Co., Ltd.
I-METTLER TOLEDO Instruments (Shanghai) Co., Ltd.
I-Hangzhou David Science and Education Instrument Co., Ltd.
I-American Thermo Fisher Co., Ltd.
I-American Thermoelectric Switzerland ARL Inkampani
Inkampani yaseSwitzerland iBRUKER
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Ukulungiswa kwama-CMC
Ukusebenzisa i-pine wood alkali cellulose pretreated by concentrated alkali decrystallization njengento eluhlaza, kusetshenziswa i-ethanol njengesinyibilikisi futhi kusetshenziswa i-sodium chloroacetate njenge-etherification.
I-CMC ene-DS ephakeme yalungiswa ngokungeza i-alkali kabili kanye ne-ejenti e-etherifying kabili. Faka i-2g ye-pine wood alkali cellulose eflaskini enezintamo ezine, bese wengeza umthamo othile we-ethanol solvent, ugovuze kahle imizuzu engama-30.
mayelana, ukuze i-cellulose ye-alkali ihlakazeke ngokugcwele. Bese wengeza inani elithile le-alkali ejenti kanye ne-sodium chloroacetate ukuze kusabele isikhathi esithile ezingeni lokushisa elithile le-etherification.
Ngemuva kwesikhathi, ukungezwa kwesibili kwe-alkaline ejenti kanye ne-sodium chloroacetate kulandelwa i-etherification isikhathi esithile. Ngemuva kokuthi ukusabela sekuphelile, pholisa bese upholisa, bese
Hlukanisa phakathi nendawo ngenani elifanele le-glacial acetic acid, bese uhlunga ukumunca, geza futhi wome.
Ukulungiswa kwama-HECs
Ukusebenzisa i-pine wood alkali cellulose pretreated ne-alkali decrystallization egxilile njengento eluhlaza, i-ethanol njenge-solvent kanye ne-2-chloroethanol njenge-etherification.
I-HEC ene-MS ephakeme yalungiswa ngokungeza i-alkali kabili kanye ne-ejenti yokufaka i-etherifying kabili. Faka i-2g ye-pine wood alkali cellulose eflaskini enezintamo ezine, bese wengeza umthamo othize wama-90% (ingxenye yevolumu) ye-ethanol, gudluza.
Govuza isikhathi esithile ukuze uhlakaze ngokugcwele, bese wengeza inani elithile le-alkali, futhi kancane kancane ushise, engeza umthamo othile we-2-
I-Chloroethanol, efakwe etherified ekushiseni okungaguquki isikhathi esithile, bese yengeza i-sodium hydroxide esele kanye no-2-chloroethanol ukuze iqhubeke i-etherification isikhathi esithile. phatha
Ngemva kokuqedwa kokusabela, nciphisa ngenani elithile le-glacial acetic acid, bese ekugcineni hlunga ngesihlungi sengilazi (G3), geza, bese womisa.
Ukulungiswa kwe-HEMCC
Ukusebenzisa i-HEC elungiselelwe ku-3.2.3.4 njengento eluhlaza, i-ethanol njengendlela yokusabela, ne-sodium chloroacetate njenge-ejenti etherifying yokulungiselela.
I-HECMC. Inqubo ethize ithi: thatha inani elithile le-HEC, ulifake ku-100 mL yefulaski enezintamo ezine, bese wengeza inani elithile levolumu.
I-ethanol engu-90%, inyakazisa okwesikhashana ukuze ihlakazeke ngokugcwele, engeza inani elithile le-alkali ngemva kokushisisa, bese wengeza kancane kancane.
I-sodium chloroacetate, i-etherification emazingeni okushisa avamile iphela ngemva kwesikhathi esithile. Ngemuva kokuthi ukusabela sekuqediwe, kwenze kube lula nge-glacial acetic acid ukuze unciphise, bese usebenzisa isihlungi sengilazi (G3)
Ngemuva kokuhlunga, ukuwasha nokomisa.
Ukuhlanzwa kwe-cellulose ethers
Enqubweni yokulungiswa kwe-cellulose ether, eminye imikhiqizo ekhiqizwayo ivame ukukhiqizwa, ikakhulukazi usawoti we-sodium chloride we-inorganic kanye nokunye.
ukungcola. Ukuze kuthuthukiswe ikhwalithi ye-cellulose ether, ukuhlanzwa okulula kwenziwa ku-ether ye-cellulose etholiwe. ngoba basemanzini
Kukhona ukunyibilika okuhlukile, ngakho-ke ukuhlolwa kusebenzisa ingxenyena ethile yevolumu ye-ethanol enamanzi ukuze kuhlanzeke ama-ether amathathu e-cellulose alungisiwe.
ushintsho.
Beka isampula ye-cellulose ether elungiswe ngekhwalithi ethile ku-beaker, engeza inani elithile le-ethanol engu-80% eshiswe ngaphambili yaba ngu-60 ℃ ~ 65 ℃, futhi ugcine ukunyakaziswa komshini ku-60 ℃ ~ 65 ℃ endaweni yokushisa ehlala njalo yokushisa kazibuthe. ngo-10 ℃. imiz. Thatha amandla amakhulu ukuze wome
Kubhika elihlanzekile, sebenzisa i-nitrate esiliva ukuhlola ama-ion e-chloride. Uma kukhona imvula emhlophe, yihlunge ngesihlungi sengilazi bese uthatha okuqinile
Phinda izinyathelo zangaphambilini zengxenye yomzimba, kuze kube yilapho i-filtrate ngemva kokwengeza i-drop engu-1 yesisombululo se-AgNO3 ingenayo i-precipitate emhlophe, okungukuthi, ukuhlanzwa nokugeza kuqediwe.
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ku-(ikakhulukazi ukususa ukusabela ngomkhiqizo we-NaCl). Ngemuva kokuhlunga, ukomisa, ukupholisa ekamelweni lokushisa kanye nesisindo.
ubuningi, g.
Izindlela Zokuhlola Nezimpawu Ze-Cellulose Ethers
Ukunqunywa kweDegree of Substitution (DS) kanye ne-Molar Degree of Substitution (MS)
Ukunqunywa kwe-DS: Okokuqala, kala u-0.2 g (onembile ukuya ku-0.1 mg) wesampula ye-cellulose ether ehlanziwe futhi eyomisiwe, yihlakaze
80mL wamanzi acwengekile, anyakaziswa emanzini okugeza okushisa okungashintshi ku-30 ℃ ~ 40 ℃ imizuzu engu-10. Bese ulungisa ngesisombululo se-sulfuric acid noma isisombululo se-NaOH
i-pH yesixazululo kuze kube yilapho i-pH yesisombululo isingu-8. Khona-ke kubhekhani elifakwe i-electrode yemitha ye-pH, sebenzisa isixazululo esivamile se-sulfuric acid.
Ukuze u-titrate, ngaphansi kwezimo ezinyakazayo, bheka ukufundwa kwemitha ye-pH ngenkathi i-titrating, lapho inani le-pH lesixazululo lilungiswa libe ngu-3.74,
I-titration iyaphela. Qaphela umthamo wesisombululo esijwayelekile se-sulfuric acid esisetshenziswa ngalesi sikhathi.
Isizukulwane:
Isamba sezinombolo zeproton ephezulu kanye neqembu le-hydroxyethyl
Isilinganiso senani lamaphrothoni aphezulu; I-I7 yinqwaba yeqembu le-methylene eqenjini le-hydroxyethyl
Ukuqina kwe-proton resonance peak; ukuqina kwe-proton resonance peak yamaqembu ama-5 e-methine kanye neqembu elilodwa le-methylene kuyunithi ye-glucose ye-cellulose
Ingqikithi.
Izindlela zokuhlola ezichazwe ekuhlolweni kwe-infrared characterization yama-cellulose ethers amathathu CMC, HEC kanye ne-HEECMC
Umthetho
3.2.4.3 Ukuhlolwa kwe-XRD
I-X-ray Diffraction Analysis Test Test of Characterization of Three Cellulose Ethers CMC, HEC and HEECMC
indlela yokuhlola echazwe.
3.2.4.4 Ukuhlolwa kwe-H-NMR
I-spectrometer ye-H NMR ye-HEC ikalwe nge-spectrometer ye-Avance400 H NMR ekhiqizwe ngu-BRUKER.
Kusetshenziswa i-deuterated dimethyl sulfoxide njenge-solvent, isixazululo sahlolwa yi-liquid hydrogen NMR spectroscopy. Imvamisa yokuhlola ibingu-75.5MHz.
Kufudumele, ikhambi lingu-0.5mL.
3.3 Imiphumela kanye nokuhlaziya
3.3.1 Ukwenza ngcono inqubo yokulungiselela i-CMC
Kusetshenziswa i-pine cellulose ekhishwe esahlukweni sesibili njengento eluhlaza, futhi kusetshenziswa i-sodium chloroacetate njenge-ejenti ye-etherifying, indlela yokuhlola isici esisodwa yamukelwa,
Inqubo yokulungiselela i-CMC yenziwe kahle, futhi okuguquguqukayo kokuqala kokuhlolwa kwasethwa njengoba kukhonjisiwe kuThebula 3.3. Okulandelayo yinqubo yokulungiselela i-HEC
Ezobuciko, ukuhlaziywa kwezinto ezihlukahlukene.
Ithebula 3.3 Amanani Ezinto Zokuqala
I-Factor Inani lokuqala
Ukushisa ngaphambi kokwelashwa kwe-alkalizing/℃ 40
Ukwelashwa ngaphambi kwesikhathi se-alkalizing/h 1
I-pretreatment solid-liquid ratio/(g/mL) 1:25
Ukugxila kwe-lye ngaphambi kokwelashwa/% 40
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Isigaba sokuqala sokushisa kwe-etherification/℃ 45
Isikhathi sokufakwa kwe-etherification kwesigaba sokuqala/h 1
Izinga lokushisa le-etherification lesigaba sesibili/℃ 70
Isikhathi se-etherification sesigaba sesibili/h 1
Isisekelo somthamo esigabeni se-etherification/g 2
Inani le-ejenti ye-etherifying esigabeni se-etherification/g 4.3
I-Etherified solid-liquid ratio/(g/mL) 1:15
3.3.1.1 Umthelela wezinto ezihlukene ngeziqu ze-CMC esikhundleni se-alkalization yangaphambi kokwelashwa
1. Umthelela we-pretreatment alkalization lokushisa kwidigri yokushintsha ye-CMC
Ukuze kucatshangelwe umphumela wezinga lokushisa le-alkalization ngaphambi kokwelashwa ngezinga lokushintsha ku-CMC etholiwe, esimweni sokulungisa ezinye izici njengamavelu okuqala,
Ngaphansi kwezimo, umthelela we-pretreatment alkalization lokushisa ku-CMC substitution degree kuyaxoxwa ngakho, futhi imiphumela iboniswa ku-Fig.
Ukwelashwa kwangaphambili kwe-alkalizing lokushisa/℃
Umthelela we-pretreatment alkalizing temperature on CMC substitution degree
Kuyabonakala ukuthi izinga lokushintshwa kwe-CMC liyakhuphuka ngokunyuka kwezinga lokushisa le-alkalization ngaphambi kokwelashwa, futhi izinga lokushisa le-alkalization lingu-30 °C.
Amadigri angenhla okushintsha ayancipha ngokukhuphuka kwezinga lokushisa. Lokhu kungenxa yokuthi izinga lokushisa le-alkalizing liphansi kakhulu, futhi ama-molecule awasebenzi futhi awakwazi
Ukucekela phansi ngokuphumelelayo indawo ye-cellulose ye-crystalline, okwenza kube nzima nge-ejenti e-etherifying ukungena ngaphakathi kwe-cellulose esigabeni se-etherification, futhi izinga lokusabela liphezulu ngokuqhathaniswa.
okuphansi, okuholela ezingeni eliphansi lokushintshwa komkhiqizo. Kodwa-ke, izinga lokushisa le-alkalization akufanele libe phezulu kakhulu. Njengoba izinga lokushisa likhuphuka, ngaphansi kwesenzo sokushisa okuphezulu kanye ne-alkali enamandla,
I-Cellulose ijwayele ukuwohloka kwe-oxidative, futhi izinga lokushintshwa komkhiqizo we-CMC liyehla.
2. Umthelela wesikhathi sokwelashwa ngaphambi kokwenza i-alkalinisation ku-CMC substitution degree
Ngaphansi kwesimo sokuthi izinga lokushisa ngaphambi kokwelashwa kwe-alkalization lingu-30 °C futhi ezinye izici zingamanani okuqala, umphumela wesikhathi sokwelashwa ngaphambi kokwelashwa kwe-alkalization ku-CMC kuyaxoxwa ngakho.
Umphumela wokushintsha. Izinga lokushintsha
Ukwelashwa ngaphambi kwesikhathi se-alkalizing/h
Umthelela we-pretreatment alkalinization time onI-CMCi-substitution degree
Inqubo ye-bulking ngokwayo iyashesha uma kuqhathaniswa, kodwa isisombululo se-alkali sidinga isikhathi esithile sokusabalalisa ku-fiber.
Kungabonakala ukuthi uma isikhathi se-alkalization singu-0.5-1.5h, izinga lokushintshwa komkhiqizo liyanda ngokukhula kwesikhathi se-alkalization.
Izinga lokushintshwa komkhiqizo otholiwe laliphakeme kakhulu uma isikhathi singu-1.5h, futhi izinga lokushintsha liyehla ngokunyuka kwesikhathi ngemva kuka-1.5h. Lokhu kungaba
Kungenzeka ukuthi ekuqaleni kwe-alkalization, ngokunwetshwa kwesikhathi se-alkalization, ukungena kwe-alkali ku-cellulose kwanele, ukuze i-fiber.
Isakhiwo esiyinhloko sikhululekile, sikhulisa i-etherifying agent kanye ne-medium esebenzayo
Isikhathi sokuthumela: Apr-26-2024