Etherification reaction on cellulose ether

Ts'ebetso ea etherification ea selulose e ile ea ithutoa ke mochini o lubang le reactor e susumetsang ka ho latellana, 'me hydroxyethyl cellulose le carboxymethyl cellulose li lokisitsoe ke chloroethanol le monochloroacetic acid ka ho latellana. Liphetho li bonts'itse hore karabelo ea etherification ea selulose e entsoe ka mochini o susumetsang tlas'a boemo ba ho ferekana ho matla. Cellulose e na le reactivity e ntle ea etherification, e leng molemo ho feta mokhoa oa kneader ho ntlafatsa katleho ea etherification le ho ntlafatsa phetiso ea leseli ea sehlahisoa ka tharollo e nang le metsi.) Ka hona, ho ntlafatsa matla a susumetsang a ts'ebetso ea karabelo ke tsela e molemo ea ho hlahisa sebaka sa homogeneous cellulose etherification. lihlahisoa.

Mantsoe a bohlokoa:karabelo ea etherification; Cellulose;Hydroxyethyl cellulose; Carboxymethyl cellulose

Ho nts'etsopele ea lihlahisoa tsa ether ea k'hothone e hloekisitsoeng, mokhoa oa solvent o sebelisoa haholo 'me mochine oa ho luba o sebelisoa e le thepa ea ho arabela. Leha ho le joalo, cellulose ea k'hothone e entsoe haholo ka libaka tsa kristale moo limolek'hule li hlophisitsoeng ka makhethe le haufi. Ha mochini oa ho luba o sebelisoa e le lisebelisoa tsa karabelo, letsoho la ho luba la mochini oa ho luba le lieha nakong ea karabelo, 'me khanyetso ea moemeli oa etherifying ho kenya likarolo tse fapaneng tsa selulose e kholo mme lebelo le lieha, ho fella ka nako e telele ea karabelo, karolo e phahameng ea lehlakore. karabelo le kabo e sa leka-lekaneng ea lihlopha tse nkang sebaka sa liketane tsa limolek'hule tsa cellulose.

Hangata karabelo ea etherification ea cellulose ke karabelo e fapaneng kantle le kahare. Haeba ho se na ketso e matla ea kantle, moemeli oa etherifying o thata ho kena sebakeng sa crystallization ea selulose. 'Me ka pretreatment ea k'hothone e hloekisitsoeng (e kang ho sebelisa mekhoa ea' mele ho eketsa bokaholimo ba k'hothone e hloekisitsoeng), ka nako e ts'oanang le mochine o tsosang takatso bakeng sa lisebelisoa tsa karabelo, o sebelisa karabelo e potlakileng ea etherification, ho ea ka mabaka, selulose e ka ruruha ka matla, ho ruruha. sebakeng sa cellulose amorphous le sebaka sa crystallization se atisa ho tsitsa, ho ntlafatsa ts'ebetso ea karabelo. Kabo e homogeneous ea cellulose ether substituents ho heterogeneous etherification reaction system e ka finyelloa ka ho eketsa matla a susumetsang a kantle. Kahoo e tla ba tataiso ea nako e tlang ea nts'etsopele ea naha ea rona ho nts'etsapele lihlahisoa tsa boleng bo holimo tsa cellulose etherification ka kettle ea mofuta o tsoileng matsoho joalo ka lisebelisoa tsa karabelo.

1. Karolo ea teko

1.1 Lisebelisoa tse tala tsa k'hothone tsa cellulose bakeng sa tlhahlobo

Ho latela lisebelisoa tse fapaneng tsa karabelo tse sebelisitsoeng tekong, mekhoa ea pele ea kalafo ea cellulose ea k'hothone e fapane. Ha kneader e sebelisoa e le sesebelisoa sa karabelo, mekhoa ea pele ea kalafo le eona e fapane. Ha kneader e sebelisoa e le lisebelisoa tsa karabelo, crystallinity ea selulose e hloekisitsoeng ea k'hothone e sebelisitsoeng ke 43.9%, 'me bolelele bo tloaelehileng ba selulose ea k'hothone e hloekisitsoeng ke 15 ~ 20mm. Bokhabane ba cellulose ea k'hothone e hloekisitsoeng ke 32.3% 'me bolelele bo tloaelehileng ba selulose ea k'hothone e hloekisitsoeng bo ka tlase ho 1mm ha mochine o susumetsang o sebelisoa e le lisebelisoa tsa ho arabela.

1.2 Nts'etsopele ea carboxymethyl cellulose le hydroxyethyl cellulose

Ho lokisoa ha carboxymethyl cellulose le hydroxyethyl cellulose ho ka etsoa ka ho sebelisa kneader ea 2L e le lisebelisoa tsa karabelo (karolelano ea lebelo nakong ea karabelo ke 50r/min) le 2L e susumetsang e le lisebelisoa tsa karabelo (karolelano ea lebelo nakong ea karabelo ke 500r/min).

Nakong ea karabelo, lisebelisoa tsohle tse tala li tsoa ho karabelo e thata ea palo. Sehlahisoa se fumanoang ho tsoa ho karabelo se hlatsuoa ka w = 95% ethanol, ebe se omisoa ka vacuum bakeng sa 24h tlas'a khatello e mpe ea 60 ℃ le 0.005mpa. Mongobo oa sampole e fumanoeng ke w = 2.7% ± 0.3%, mme sampole ea sehlahisoa bakeng sa tlhahlobo e hlatsuoa ho fihlela molora o le w <0.2%.

Mehato ea ho lokisa mochini oa ho luba joalo ka lisebelisoa tsa karabelo ke tse latelang:

Etherification reaction → ho hlatsoa lihlahisoa → ho omisa → granulation e grated → sephutheloana se etsoa ka kneader.

Mehato ea ho itokisa ea mochini o susumetsang e le lisebelisoa tsa karabelo ke tse latelang:

Karabelo ea etherification → ho hlatsoa lihlahisoa → ho omisa le granulation → sephutheloana se etsoa ka mochini o tsoileng matsoho.

Ho ka bonoa hore kneader e sebelisoa e le lisebelisoa tsa karabelo bakeng sa ho lokisa litšoaneleho tsa ts'ebetso e tlase ea karabelo, ho omisa le ho sila granulation mohato ka mohato, mme boleng ba sehlahisoa bo tla fokotseha haholo ts'ebetsong ea ho sila.

Litšobotsi tsa ts'ebetso ea ho lokisa ka mochini o ts'oarehang joalo ka lisebelisoa tsa karabelo ke tse latelang: ts'ebetso e phahameng ea karabelo, granulation ea sehlahisoa ha e sebelise mokhoa oa setso oa ho omisa le ho sila, mme ts'ebetso ea ho omisa le ea granulation e etsoa ka nako e le 'ngoe le lihlahisoa tse sa omisoang ka mor'a ho hlatsoa, ​​​​'me boleng ba sehlahisoa bo lula bo sa fetohe ka mokhoa oa ho omisa le oa granulation.

1.3 Tlhahlobo ea ho fapana ha X-ray

Tlhahlobo ea diffraction ea X-ray e entsoe ke Rigaku D / max-3A X-ray diffractometer, graphite monochromator, Θ Angle e ne e le 8 ° ~ 30 °, CuKα ray, khatello ea tube le phallo ea tube e ne e le 30kV le 30mA.

1.4 Tlhahlobo ea mahlaseli a infrared

Spectrum-2000PE FTIR spectrometer ea infrared e ile ea sebelisoa bakeng sa tlhahlobo ea mahlaseli a infrared. Mehlala eohle ea tlhahlobo ea spectrum ea infrared e ne e na le boima ba 0.0020g. Mehlala ena e ne e tsoakoa le 0.1600g KBr, ka ho latellana, ebe e hatelloa (ka botenya ba <0.8mm) ebe e hlahlojoa.

1.5 Ho lemoha phetiso

Phetiso e ile ea bonoa ke 721 spectrophotometer. Tharollo ea CMC w=w1% e kentsoe ka har'a sejana sa colorimetric sa 1cm ho 590nm wavelength.

1.6 Tekanyo ea ho lemoha sebaka

The HEC substitution degree ea hydroxyethyl cellulose e lekantsoe ka mokhoa o tloaelehileng oa tlhahlobo ea lik'hemik'hale. Molao-motheo ke hore HEC e ka senyeha ke HI hydroiodate ho 123 ℃, 'me tekanyo ea ho fetola HEC e ka tsejoa ka ho lekanya lintho tse bolileng tse hlahisoang ke ethylene le ethylene iodide. Tekanyo ea ho kenya hydroxymethyl cellulose le eona e ka lekoa ka mekhoa e tloaelehileng ea tlhahlobo ea lik'hemik'hale.

2. Liphetho le lipuisano

Ho sebelisoa mefuta e 'meli ea kettle ea karabelo mona: e' ngoe ke mochini oa ho luba e le sesebelisoa sa karabelo, e 'ngoe e hlohlelletsa mofuta oa ketlele joalo ka sesebelisoa sa karabelo, ka sistimi e fapaneng ea karabelo, boemo ba alkaline le sistimi e qhibilihang ea metsi a joala, karabelo ea etherification ea selulose e hloekisitsoeng ea k'hothone e ithutoa. Har'a tsona, litšoaneleho tsa thekenoloji tsa mochini oa ho luba joalo ka lisebelisoa tsa karabelo ke: Karabelong, lebelo la letsoho le lubang le ea butle, nako ea karabelo e telele, karolo ea karabelo ea lehlakore e phahame, sekhahla sa ts'ebeliso ea etherifying e tlase, 'me ho ts'oana ha kabo ea sehlopha ho karabelo ea etherizing e fokola. Ts'ebetso ea lipatlisiso e ka lekanyetsoa feela maemong a karabelo e batlang e le moqotetsane. Ho feta moo, ho feto-fetoha le taolo ea maemo a mantlha a karabelo (joalo ka karo-karolelano ea ho hlapa, mahloriso a alkali, lebelo la letsoho la ho luba mochini oa ho luba) li futsanehile haholo. Ho thata ho fihlela tekano e lekantsoeng ea karabelo ea etherification le ho ithuta phetisetso ea bongata le ho kenella ha ts'ebetso ea karabelo ea etherification ka botebo. Likarolo tsa ts'ebetso ea li-reactor tse susumetsang joalo ka lisebelisoa tsa karabelo ke: lebelo le susumetsang ka potlako, lebelo la karabelo e potlakileng, sekhahla sa ts'ebeliso e phahameng ea etherizing, kabo e ts'oanang ea li-substituents tsa etherizing, maemo a ka fetohang le a laolehang.

Carboxymethyl cellulose CMC e ne e hlophisitsoe ke lisebelisoa tsa kneader reaction le lisebelisoa tse susumetsang tsa reactor ka ho latellana. Ha kneader e ne e sebelisoa e le lisebelisoa tsa ho arabela, matla a susumetsang a ne a le tlaase 'me lebelo le tloaelehileng la ho potoloha e ne e le 50r / min. Ha mochine o susumetsang o ne o sebelisoa e le lisebelisoa tsa ho arabela, matla a susumetsang a ne a le holimo 'me lebelo le tloaelehileng la ho potoloha e ne e le 500r / min. Ha tekanyo ea molar ea monochloroacetic acid ho cellulose monosaccharide e ne e le 1:5:1, nako ea karabelo e ne e le 1.5h ho 68 ℃. Phatlalatso e bobebe ea CMC e fumanoeng ka mochini oa ho luba e ne e le 98.02% mme katleho ea etherification e ne e le 72% ka lebaka la ho kenella hantle ha CM ho chloroacetic acid etherifying agent. Ha mochini o susumetsang o ne o sebelisoa e le sesebelisoa sa karabelo, ho kenella ha sesebelisoa sa etherifying ho ne ho le betere, phetisetso ea CMC e ne e le 99.56%, 'me katleho ea karabelo ea etherizing e eketsehile ho fihla ho 81%.

Hydroxyethyl cellulose HEC e hlophisitsoe ka kneader le reactor e susumetsang joalo ka lisebelisoa tsa karabelo. Ha kneader e ne e sebelisoa e le lisebelisoa tsa karabelo, ts'ebetso ea karabelo ea etherizing e ne e le 47% mme ho qhibiliha ha metsi ho ne ho fokola ha ho kenella ha chloroethyl alcohol etherizing agent e le mpe 'me karolelano ea molar ea chloroethanol le cellulose monosaccharide e ne e le 3:1 ho 60 ℃ bakeng sa 4h. . Ke feela ha tekanyo ea molar ea chloroethanol ho cellulose monosaccharides e le 6: 1, lihlahisoa tse nang le metsi a monate a ho qhibiliha li ka thehoa. Ha mochini o susumetsang o ne o sebelisoa e le sesebelisoa sa karabelo, ho kenella ha chloroethyl alcohol etherification agent ho bile betere ho 68℃ bakeng sa 4h. Ha tekanyo ea molar ea chloroethanol ho cellulose monosaccharide e ne e le 3: 1, HEC e hlahisitsoeng e ne e e-na le ho qhibiliha ha metsi ho betere, 'me katleho ea etherification reaction e ile ea eketseha ho 66%.

Karabelo e sebetsang hantle le lebelo la karabelo la etherizing agent chloroacetic acid li phahame haholo ho feta tsa chloroethanol, 'me mochini o susumetsang joalo ka sesebelisoa sa etherizing reaction o na le melemo e hlakileng ho feta kneader, e ntlafatsang haholo ts'ebetso ea etherizing reaction. Phetisetso e phahameng ea CMC e boetse e supa ka mokhoa o sa tobang hore mochini o susumetsang joalo ka lisebelisoa tsa karabelo tsa etherizing o ka ntlafatsa homogeneity ea karabelo ea etherizing. Sena se bakoa ke hore ketane ea cellulose e na le lihlopha tse tharo tsa hydroxyl lesale la sehlopha se seng le se seng sa glucose, 'me feela sebakeng se ruruhileng haholo kapa se qhibilihileng moo lipara tsa cellulose hydroxyl tsa limolek'hule tsa etherifying agent li ka fihlellehang. Karabelo ea etherification ea selulose hangata ke karabelo e fapaneng ho tloha kantle ho ea kahare, haholo sebakeng sa crystalline selulose. Ha sebopeho sa kristale sa cellulose se lula se tiile ntle le phello ea matla a ka ntle, moemeli oa etherifying o thata ho kena mohahong oa kristale, o amang homogeneity ea karabelo e fapaneng. Ka hona, ka ho lokisa k'hothone e hloekisitsoeng (e kang ho eketsa bokaholimo bo khethehileng ba k'hothone e hloekisitsoeng), ts'ebetso ea k'hothone e hloekisitsoeng e ka ntlafatsoa. Ka tekanyo e kholo ea ho hlapa (ethanol / cellulose kapa isopropyl joala / selulose le karabelo e potlakileng e susumetsang, ho ea ka mabaka, taelo ea sebaka sa cellulose crystallization e tla fokotseha, ka nako ena selulose e ka ruruha ka matla, e le hore ho ruruha ea sebaka sa amorphous le crystalline cellulose se atisa ho lumellana, Ka hona, reactivity ea sebaka sa amorphous le sebaka sa crystalline se tšoana.

Ka tlhahlobo ea spectrum ea infrared le tlhahlobo ea phallo ea X-ray, ts'ebetso ea karabelo ea etherification ea selulose e ka utloisisoa ka ho hlaka haholoanyane ha mochini o susumetsang o sebelisoa e le sesebelisoa sa etherification reaction.

Mona, ho ile ha sekasekoa pono ea infrared le x-ray diffraction spectra. Boitšoaro ba etherification ba CMC le HEC bo ile ba etsoa ka mokhoa o tsoileng matsoho tlas'a maemo a karabelo a hlalositsoeng ka holimo.

Tlhahlobo ea mahlaseli a infrared e bontša hore karabelo ea etheration ea CMC le HEC e fetoha khafetsa ka ho atolosoa ha nako ea ho arabela, tekanyo ea ho fetola e fapane.

Ka tlhahlobo ea sebopeho sa X-ray diffraction, crystallinity ea CMC le HEC e batla e le zero ka ho atolosoa ha nako ea karabelo, e bonts'a hore ts'ebetso ea decrystallization e se e lemohuoe sethaleng sa alkalization le sethala sa ho futhumatsa pele ho karabelo ea etherification ea k'hothone e hloekisitsoeng. . Ka hona, carboxymethyl le hydroxyethyl etherification reactivity ea k'hothone e hloekisitsoeng ha e sa thibeloa haholo ke kristale ea k'hothone e hloekisitsoeng. E amana le ho phunyeletsa ha moemeli oa etherifying. E ka bonts'a hore karabelo ea etherification ea CMC le HEC e etsoa ka mochini o susumetsang joalo ka lisebelisoa tsa karabelo. Tlas'a lebelo le phahameng le susumetsang, ho molemo ts'ebetsong ea decrystallization ea k'hothone e hloekisitsoeng sethaleng sa alkalization le sethaleng sa ho futhumatsa pele ho karabelo ea etherification, 'me e thusa moemeli oa etherification hore a kenelle ka har'a selulose, e le ho ntlafatsa ts'ebetso ea etherification reaction le ho feto-fetoha ha maemo. .

Qetellong, thuto ena e totobatsa tšusumetso ea matla a susumetsang le lintlha tse ling mabapi le katleho ea karabelo nakong ea ts'ebetso. Ka hona, tlhahiso ea phuputso ena e itšetlehile ka mabaka a latelang: Ka heterogeneous etheration itsoara joang tsamaiso, tshebediso ya kholo karo-karolelano ea bate le phahameng susumetsang matla, joalo-joalo, ke maemo a motheo bakeng sa ho lokisetsa hoo e ka bang homogeneous selulose ether le substituent sehlopha. kabo; Sistimi e ikhethileng e fapaneng ea etheration reaction, ether e phahameng ea selulose e nang le kabo e lekanang ea li-substituent e ka lokisoa ka ho sebelisa reactor e susumetsang joalo ka lisebelisoa tsa karabelo, e bonts'ang hore tharollo ea metsi a cellulose ether e na le phetiso e phahameng, e bohlokoa haholo ho holisa thepa. le mesebetsi ea cellulose ether. Mochini oa ho luba o sebelisoa e le lisebelisoa tsa karabelo ho ithuta karabelo ea etherification ea k'hothone e hloekisitsoeng. Ka lebaka la matla a tlase a susumetsang, ha e ntle bakeng sa ho kenella ha moemeli oa etherification, 'me e na le mefokolo e kang karolo e phahameng ea maikutlo a mahlakoreng le ho se tšoane ha kabo e fokolang ea li-substituent tsa etherification.