Ukusabela kwe-Etherification ku-cellulose ether

Umsebenzi we-etherification we-cellulose wacwaningwa ngomshini wokuxova kanye ne-reactor eshukumisayo ngokulandelana, futhi i-hydroxyethyl cellulose ne-carboxymethyl cellulose zalungiswa yi-chloroethanol ne-monochloroacetic acid ngokulandelana. Imiphumela yabonisa ukuthi ukusabela kwe-etherification ye-cellulose kwenziwa ngokushukumisa i-reactor ngaphansi kwesimo sokuyaluza okukhulu. I-Cellulose inokuphinda isebenze kahle kwe-etherification, engcono kunendlela yokuxova ekuthuthukiseni ukusebenza kahle kwe-etherification kanye nokuthuthukisa ukudluliswa kokukhanya komkhiqizo ngesisombululo esinamanzi.) Ngakho-ke, ukuthuthukisa ukushuba okunyakazisayo kwenqubo yokusabela kuyindlela engcono yokuthuthukisa ukufaka esikhundleni se-homogeneous cellulose etherification. imikhiqizo.

Amagama angukhiye:ukusabela kwe-etherification; I-cellulose;I-Hydroxyethyl cellulose; I-Carboxymethyl cellulose

Ekuthuthukisweni kwemikhiqizo ye-cotton cellulose ether ecwengekile, indlela ye-solvent isetshenziswa kakhulu futhi umshini wokuxova usetshenziswa njengemishini yokusabela. Kodwa-ke, i-cotton cellulose yakhiwa ikakhulukazi izifunda zekristalu lapho ama-molecule ahlelwe kahle futhi eduze. Lapho umshini wokuxova usetshenziswa njengemishini yokusabela, ingalo yokuxova yomshini wokuxova ihamba kancane ngesikhathi sokusabela, futhi ukumelana kwe-ejenti etherifying ukufaka izingqimba ezihlukene ze-cellulose kukhulu futhi ijubane lihamba kancane, okuholela esikhathini eside sokuphendula, ingxenye ephezulu yohlangothi. ukusabela kanye nokusatshalaliswa okungalingani kwamaqembu angena esikhundleni kumaketanga wamangqamuzana e-cellulose.

Ngokuvamile ukusabela kwe-etherification ye-cellulose kuwukusabela okungafani ngaphandle nangaphakathi. Uma singekho isenzo esishukumisayo sangaphandle, i-etherifying agent inzima ukungena endaweni ye-crystallization ye-cellulose. Futhi ngokusebenzisa pretreatment ukotini elicwengekile (njengokusebenzisa izindlela ngokomzimba ukwandisa ubuso ukotini elicwengekile), ngesikhathi esifanayo ne-reactor enyakazayo imishini yokusabela, usebenzisa okusheshayo enyakazayo etherification ukusabela, ngokusho yokucabanga, cellulose kungaba kakhulu ukuvuvukala, ukuvuvukala. indawo ye-cellulose amorphous kanye nendawo ye-crystallization ijwayele ukuhambisana, ithuthukise umsebenzi wokusabela. Ukusatshalaliswa kwe-homogeneous kwama-substituents e-cellulose ether ohlelweni lokusabela kwe-etherification ehlukahlukene kungazuzwa ngokwandisa amandla ashukumisayo angaphandle. Ngakho-ke kuzoba indlela yentuthuko yesikhathi esizayo yezwe lethu ukuthuthukisa imikhiqizo yekhwalithi ephezulu ye-cellulose etherification enegedlela lokusabela elinyakaziswayo njengemishini yokusabela.

1. Ingxenye yokuhlola

1.1 I-cotton cellulose ecolisisiwe impahla eluhlaza ukuze ihlolwe

Ngokusho kwemishini ehlukene yokusabela esetshenziswe ocwaningweni, izindlela zokwelashwa kwangaphambili kwe-cotton cellulose zihlukile. Lapho i-kneader isetshenziswa njengemishini yokusabela, izindlela zokwelashwa nazo zihlukile. Lapho i-kneader isetshenziswa njengemishini yokusabela, i-crystallinity ye-cotton cellulose ehlanzekile esetshenzisiwe i-43.9%, kanti ubude obujwayelekile be-cotton cellulose ecwengiwe yi-15 ~ 20mm. Ubucwebe be-cellulose kakotini ocwengiwe bungama-32.3% kanti ubude obumaphakathi be-cotton cellulose ecolisisiwe bungaphansi kuka-1mm lapho i-reactor enyakazayo isetshenziswa njengemishini yokusabela.

1.2 Ukuthuthukiswa kwe-carboxymethyl cellulose ne-hydroxyethyl cellulose

Ukulungiswa kwe-carboxymethyl cellulose kanye ne-hydroxyethyl cellulose kungenziwa kusetshenziswa i-2L kneader njengemishini yokusabela (isivinini esimaphakathi ngesikhathi sokusabela singu-50r/min) kanye ne-reactor eshukumisayo engu-2L njengemishini yokusabela (isivinini esimaphakathi ngesikhathi sokuphendula singama-500r/min).

Ngesikhathi sokusabela, zonke izinto zokusetshenziswa zitholakala ekuphenduleni okuqinile kwenani. Umkhiqizo otholwe ekuphenduleni ugezwa nge-ethanol w=95%, bese womiswa nge-vacuum amahora angu-24 ngaphansi kwengcindezi engemihle engu-60 ℃ no-0.005mpa. Umswakamo wesampula otholiwe ungu-w=2.7%±0.3%, kanti isampula lomkhiqizo lohlaziyo liyawashwa kuze kube umlotha w<0.2%.

Izinyathelo zokulungiselela umshini wokuxova njengemishini yokusabela zimi kanje:

Ukusabela kwe-etherification → ukuwashwa komkhiqizo → ukomisa → i-granulation eshiziwe → ukupakisha kwenziwa ku-kneader.

Izinyathelo zokulungiselela ze-reactor enyakazayo njengemishini yokusabela zimi kanje:

Ukusabela kwe-etherification → ukuwashwa komkhiqizo → ukomiswa kanye ne-granulation → ukupakisha kwenziwa kureactor enyakaziswayo.

Kuyabonakala ukuthi i-kneader isetshenziswa njengemishini yokusabela yokulungiswa kwezici zokuphendula kahle okuphansi, ukomisa nokugaya i-granulation isinyathelo ngesinyathelo, futhi ikhwalithi yomkhiqizo izoncishiswa kakhulu enqubo yokugaya.

Izici zenqubo yokulungiselela nge-reactor enyakaziswayo njengemishini yokusabela zimi kanje: ukusebenza kahle kokusabela okuphezulu, i-granulation yomkhiqizo ayisebenzisi indlela yenqubo ye-granulation yendabuko yokomisa nokugaya, futhi inqubo yokomisa kanye ne-granulation yenziwa ngesikhathi esifanayo imikhiqizo engomisiwe ngemva kokugeza, futhi izinga lomkhiqizo lihlala lingashintshile ekumisweni kwenqubo yokumisa kanye ne-granulation.

1.3 Ukuhlaziywa kwe-X-ray diffraction

Ukuhlaziywa kwe-X-ray diffraction kwenziwa yi-Rigaku D/max-3A X-ray diffractometer, i-graphite monochromator, i-Θ Angle yayingu-8°~30°, i-CuKα ray, i-tube pressure kanye nokugeleza kweshubhu kwakungama-30kV kanye ne-30mA.

1.4 Ukuhlaziywa kwe-infrared spectrum

I-Spectrum-2000PE FTIR infrared spectrometer isetshenziselwe ukuhlaziya i-infrared spectrum. Wonke amasampuli okuhlaziya i-infrared spectrum ayenesisindo esingu-0.0020g. Lawa masampuli axutshwe no-0.1600g KBr, ngokulandelana, abese ecindezelwa (ngobukhulu obungu-<0.8mm) futhi ahlaziywa.

1.5 Ukutholwa kwe-Transmittance

I-transmittance itholwe yi-721 spectrophotometer. Isixazululo se-CMC w=w1% sifakwe esitsheni sombala esingu-1cm esingu-590nm wavelength.

1.6 Izinga lokutholwa kokushintshwa

I-HEC substitution degree ye-hydroxyethyl cellulose ikalwe ngendlela evamile yokuhlaziya amakhemikhali. Umgomo wukuthi i-HEC ingabola nge-HI hydroiodate ku-123℃, futhi izinga lokushintsha i-HEC lingaziwa ngokukala izinto ezibolile ezikhiqizwa i-ethylene ne-ethylene iodide. Izinga lokufaka esikhundleni se-hydroxymethyl cellulose lingabuye lihlolwe ngezindlela ezijwayelekile zokuhlaziya amakhemikhali.

2. Imiphumela kanye nengxoxo

Izinhlobo ezimbili zegedlela lokusabela zisetshenziswa lapha: eyodwa umshini wokuxova njengemishini yokusabela, enye inyakazisa igedlela lokusabela njengemishini yokusabela, ohlelweni lokusabela oluhlukahlukene, isimo se-alkaline nohlelo lokuncibilikisa amanzi anotshwala, ukusabela kwe-etherification kwe-cotton cellulose ecwengiwe kuyafundwa. Phakathi kwazo, izici zobuchwepheshe zomshini wokuxova njengemishini yokusabela yilezi: Ekuphenduleni, ijubane lengalo exovayo lihamba kancane, isikhathi sokusabela side, ingxenye yokusabela ohlangothini iphezulu, izinga lokusebenzisa i-ejenti etherifying liphansi, futhi ukufana kokushintshanisa ukusatshalaliswa kweqembu ekuphenduleni kwe-etherizing kubi. Inqubo yocwaningo ingakhawulelwa kuphela ezimeni zokusabela eziwumngcingo. Ukwengeza, ukulungiswa nokulawulwa kwezimo eziyinhloko zokusabela (njengesilinganiso sokugeza, ukugxilisa kwe-alkali, isivinini sengalo yokuxova umshini wokuxova) kubi kakhulu. Kunzima ukufeza ukufana okulinganiselwe kokusabela kwe-etherification kanye nokufunda ukudluliswa kobuningi kanye nokungena kwenqubo yokusabela kwe-etherification ngokujula. Izici zenqubo ze-reactor enyakazayo njengemishini yokusabela yilezi: isivinini esishukumisayo esisheshayo ekuphenduleni, isivinini sokusabela ngokushesha, izinga eliphezulu lokusetshenziswa kwe-ejenti e-etherizing, ukusatshalaliswa okufanayo kwezinto ezifakwa etherizing, izimo zokusabela eziyinhloko ezilungisekayo nezilawulekayo.

I-Carboxymethyl cellulose CMC yalungiswa ngemishini yokusabela ye-kneader kanye nemishini yokusabela ye-reactor eshukumisayo ngokulandelanayo. Lapho i-kneader isetshenziswa njengemishini yokusabela, umfutho onyakazayo wawuphansi futhi isivinini sokuzungeza esimaphakathi sasingu-50r/min. Lapho i-reactor enyakazayo isetshenziswa njengemishini yokusabela, umfutho onyakazayo wawuphezulu futhi isivinini sokuzungeza esimaphakathi sasingu-500r/min. Lapho isilinganiso se-molar se-monochloroacetic acid ku-cellulose monosaccharide sasingu-1:5:1, isikhathi sokusabela sasingu-1.5h ku-68℃. Ukudlulisa ukukhanya kwe-CMC okutholwe ngomshini wokuxova bekungu-98.02% futhi ukusebenza kahle kwe-etherification kwaba ngu-72% ngenxa yokungena kahle kwe-CM ku-ejenti ye-chloroacetic etherifying acid. Lapho i-reactor enyakazayo isetshenziswa njengemishini yokusabela, ukungeneka kwe-ejenti yokufaka i-etherifying kwakungcono, ukudluliswa kwe-CMC kwaba ngama-99.56%, kanye nokusebenza kahle kwe-etherizing kukhuphuke kwafinyelela ku-81%.

I-Hydroxyethyl cellulose HEC yalungiswa nge-kneader kanye ne-reactor eshukumisayo njengemishini yokusabela. Lapho i-kneader isetshenziswa njengesisetshenziswa sokuphendula, ukusebenza kahle kwe-etherizing agent kwaba ngu-47% futhi ukuncibilika kwamanzi kwakungenamandla lapho ukufinyeleleka kwe-chloroethyl alcohol etherizing agent kwakungekubi kanye nesilinganiso se-molar ye-chloroethanol ne-cellulose monosaccharide sasingu-3:1 ku-60 ℃ amahora angu-4. . Kuphela uma isilinganiso se-molar se-chloroethanol ne-cellulose monosaccharides singu-6:1, lapho imikhiqizo enokuncibilika okuhle kwamanzi ingakhiwa. Lapho i-reactor enyakazayo isetshenziswa njengesisetshenziswa sokusabela, ukungeneka kwe-ejenti ye-chloroethyl alcohol etherification kwaba ngcono ku-68℃ amahora angu-4. Lapho isilinganiso se-molar se-chloroethanol ku-cellulose monosaccharide singu-3:1, i-HEC eyaba umphumela yaba nokuncibilika okungcono kwamanzi, futhi ukusebenza kahle kokusabela kwe-etherification kukhushulelwe ku-66%.

Ukusebenza kahle kokusabela kanye nesivinini sokuphendula se-etherizing agent chloroacetic acid kuphezulu kakhulu kunaleyo ye-chloroethanol, futhi i-reactor enyakazayo njengemishini yokusabela e-etherizing inezinzuzo ezisobala kune-kneader, okuthuthukisa kakhulu ukusebenza kahle kwe-etherizing. Ukudluliswa okuphezulu kwe-CMC nakho kukhombisa ngokungaqondile ukuthi i-reactor enyakazayo njengemishini yokusabela etherizing ingathuthukisa i-homogeneity yokusabela kwe-etherizing. Lokhu kungenxa yokuthi uchungechunge lwe-cellulose lunamaqembu amathathu e-hydroxyl eringini ngayinye yeqembu le-glucose, futhi kuphela esimweni esivuvuke kakhulu noma esincibilikile wonke amapheya e-cellulose hydroxyl ama-ejenti e-etherifying afinyeleleka. Ukusabela kwe-etherification ye-cellulose kuvame ukusabela okuhlukile kusuka ngaphandle kuya ngaphakathi, ikakhulukazi endaweni ye-crystalline ye-cellulose. Lapho isakhiwo se-crystal se-cellulose sihlala siqinile ngaphandle komphumela wamandla angaphandle, i-etherifying agent inzima ukufaka isakhiwo se-crystalline, esithinta i-homogeneity ye-reaction heterogeneous. Ngakho-ke, ngokulungisa ukotini ocolisisiwe (njengokwandisa indawo ethile yokotini ocwengiwe), ukuphinda kusebenze ukotini ocolile kungathuthukiswa. Esilinganisweni esikhulu sokugeza (i-ethanol/cellulose noma i-isopropyl alcohol/cellulose kanye nesivinini esisheshayo esishukumisayo, ngokusho kokucabanga, ukuhleleka kwe-cellulose crystallization zone kuzoncishiswa, ngalesi sikhathi i-cellulose ingavuvuka kakhulu, ukuze ukuvuvukala ye-amorphous kanye ne-crystalline cellulose zone ijwayele ukuhambisana, Ngakho-ke, ukusebenza kabusha kwesifunda se-amorphous kanye nesifunda se-crystalline kuyafana.

Ngokuhlaziywa kwe-infrared spectrum kanye nokuhlaziywa kwe-X-ray diffraction, inqubo yokusabela kwe-etherification ye-cellulose ingaqondwa ngokucace kakhudlwana lapho i-reactor enyakazayo isetshenziswa njengemishini yokusabela etherification.

Lapha, i-infrared spectra kanye ne-X-ray diffraction spectra yahlaziywa. Ukusabela kwe-etherification kwe-CMC ne-HEC kwenziwa ku-reactor enyakazayo ngaphansi kwezimo zokusabela ezichazwe ngenhla.

Ukuhlaziywa kwe-spectrum ye-infrared kubonisa ukuthi ukusabela kwe-etheration ye-CMC ne-HEC kushintsha njalo ngokwandisa isikhathi sokusabela, izinga lokushintsha lihlukile.

Ngokuhlaziywa kwephethini ye-X-ray diffraction, ubucwebe be-CMC ne-HEC buba ku-zero ngokwelulwa kwesikhathi sokuphendula, okubonisa ukuthi inqubo yokukhipha amakristalu ngokuyisisekelo yenziwe esigabeni se-alkalization kanye nesiteji sokushisa ngaphambi kokusabela kwe-etherification kakotini ocolisisiwe. . Ngakho-ke, ukuphinda kusebenze kabusha kwe-carboxymethyl kanye ne-hydroxyethyl etherification kakotini ocolisisiwe akusavinjelwe ngokuyinhloko ukucwebezela kukakotini ocolisisiwe. Ihlobene nokungena kwe-ejenti ye-etherifying. Kungaboniswa ukuthi ukusabela kwe-etherification ye-CMC ne-HEC kwenziwa nge-reactor enyakazayo njengemishini yokusabela. Ngaphansi kokunyakaziswa kwesivinini esikhulu, kunenzuzo enqubweni yokukhipha amakristalu ukotini ocolisisiwe esigabeni se-alkalization kanye nesiteji sokushisa ngaphambi kokusabela kwe-etherification, futhi kusiza i-ejenti ye-etherification ukuthi ingene ku-cellulose, ukuze kuthuthukiswe ukusebenza kahle kokusabela kwe-etherification kanye nokushintshaniswa okufanayo. .

Sengiphetha, lolu cwaningo lugcizelela ithonya lamandla anyakazayo nezinye izici ekusebenzeni kahle kokusabela phakathi nenqubo yokusabela. Ngakho-ke, isiphakamiso salolu cwaningo sisekelwe kulezi zizathu ezilandelayo: Kuhlelo lokusabela lwe-etheration olungafani, ukusetshenziswa kwesilinganiso esikhulu sokugeza kanye nokuqina okuphezulu okushukumisayo, njll., yizimo eziyisisekelo zokulungiswa kwe-ether ye-cellulose engaba yi-homogeneous neqembu elingena esikhundleni. ukusatshalaliswa; Kusistimu ethile yokusabela kwe-etheration ehlukile, ukusebenza okuphezulu kwe-cellulose ether ene-ether ecishe ibe ngokufanayo yokusatshalaliswa kwezithako ezithile kungalungiselelwa ngokusebenzisa i-reactor enyakazayo njengemishini yokusabela, okubonisa ukuthi isixazululo se-cellulose ether samanzi sinokudluliswa okuphezulu, okubaluleke kakhulu ukukhulisa izakhiwo. kanye nemisebenzi ye-cellulose ether. Umshini wokuxova usetshenziswa njengemishini yokusabela ukutadisha ukusabela kwe-etherification kakotini ocolisisiwe. Ngenxa yomfutho ophansi onyakazayo, ayilungele ukungena kwe-etherification, futhi inobubi obuthile njengengxenye ephezulu yokusabela okuseceleni kanye nokungafani kokusabalalisa okungekuhle kwama-etherification substituent.