1. Ihame ry'imiterere n'itegurwa rya eteri ya selulose
Ishusho ya 1 igaragaza imiterere isanzwe ya eteri za selulosi. Buri gice cya bD-anhydroglucose (igice gisubiramo cya selulosi) gisimbura itsinda rimwe ku myanya ya C (2), C (3) na C (6), ni ukuvuga ko hashobora kubaho amatsinda atatu ya eteri. Bitewe n'imigozi ya hydrogen ihuza imiyoboro ya hydrogen hagati y'umuyoboro n'imiyoboro ihuza imiyoboro ya hydrogen.macromolecules za selulose, biragoye gushonga mu mazi no mu bintu hafi ya byose bishongesha mu bimera. Kwinjizwa mu matsinda ya eteri binyuze mu gushonga mu buryo bwa eteri byangiza imigozi ya hydrogen imbere mu ngirabuzimafatizo n'imbere mu ngirabuzimafatizo, bikongera ubushobozi bwayo bwo gushonga mu mazi, kandi bikongera cyane ubushobozi bwayo bwo gushonga mu mazi.
Ibintu bisanzwe bisimbura eteri ni amatsinda ya alkoxy afite uburemere buke bwa molekile (atome 1 kugeza kuri 4 za karuboni) cyangwa amatsinda ya hydroxyalkyl, ashobora gusimburwa n'andi matsinda akora nka karuboni, hydroxyl cyangwa amino. Ibintu bishobora gusimbura ubwoko bumwe, bubiri cyangwa bwinshi butandukanye. Ku ruhande rw'uruhererekane rwa cellulose macromolecular, amatsinda ya hydroxyl ari ku myanya ya C (2), C (3) na C (6) ya buri gice cya glucose asimburwa mu bipimo bitandukanye. Mu by'ukuri, eteri ya cellulose muri rusange ntabwo ifite imiterere yihariye ya shimi, uretse ibicuruzwa bisimbura burundu ubwoko bumwe bw'itsinda (amatsinda yose atatu ya hydroxyl asimburwa). Ibi bicuruzwa bishobora gukoreshwa gusa mu isesengura rya laboratwari no mu bushakashatsi, kandi nta gaciro bifite mu bucuruzi.
(a) Imiterere rusange y'ibice bibiri bya anhydroglucose by'uruhererekane rwa molekile ya cellulose ether, R1~R6=H, cyangwa ikintu gisimbura organic;
(b) Igice cy'uruhererekane rw'ibintu bya karuboksimetiliselulose ya hydroxyethyl, urwego rwo gusimbuza carboxymethyl ni 0.5, urwego rwo gusimbuza hydroxyethyl ni 2.0, naho urwego rwo gusimbuza molar ni 3.0. Iyi miterere igaragaza urwego mpuzandengo rw'impinduka z'amatsinda ya etherified, ariko ibintu bisimbura mu by'ukuri ni ibintu bidasanzwe.
Kuri buri gisimbura, ingano yose ya etherification igaragazwa n'urwego rw'agaciro ka DS yo gusimbuza. Intera ya DS ni 0 ~ 3, bingana n'umubare mpuzandengo w'amatsinda ya hydroxyl yasimbuwe n'amatsinda ya etherification kuri buri gice cya anhydroglucose.
Kuri ether za hydroxyalkyl cellulose, igisubizo cyo gusimbuza kizatangira gusohora etherification iturutse ku matsinda mashya ya hydroxyl yigenga, kandi urwego rwo gusimbuza rushobora gupimwa hakurikijwe agaciro ka MS, ni ukuvuga urwego rwa molar rwo gusimbuza. Igaragaza umubare mpuzandengo wa moles za etherifying agent reactant zongewe kuri buri gice cya anhydroglucose. Reactant isanzwe ni ethylene oxide kandi umusaruro ufite substituent ya hydroxyethyl. Ku Ishusho ya 1, agaciro ka MS k'umusaruro ni 3.0.
Mu buryo bw'imitekerereze, nta mupaka ntarengwa w'agaciro ka MS uhari. Niba agaciro ka DS k'urugero rwo gusimbuza kuri buri tsinda ry'impeta ya glucose kazwi, uburebure bw'uruhererekane rw'uruhererekane rw'uruhererekane rwa ether Bamwe mu bakora kandi bakunze gukoresha igice cy'uburemere (wt%) cy'amatsinda atandukanye ya etherification (nka -OCH3 cyangwa -OC2H4OH) kugira ngo bagaragaze urwego n'ingano y'uburemere aho kwerekana agaciro ka DS na MS. Igice cy'uburemere bwa buri tsinda n'agaciro karyo ka DS cyangwa MS bishobora guhindurwa hakoreshejwe uburyo bworoshye bwo kubara.
Inyinshi muri eteri za selulosi ni polimeri zishonga mu mazi, izindi nazo zishonga mu buryo bw’umwimerere. Eteri ya selulosi ifite imiterere yo gukora neza cyane, igiciro gito, gutunganywa byoroshye, uburozi buke n’ubwoko bwinshi, kandi amashami akenewe n’akoreshwa aracyari kwiyongera. Nk’inyongera, eteri ya selulosi ifite ubushobozi bukomeye bwo gukoreshwa mu nzego zitandukanye z’inganda. Ishobora kuboneka muri MS/DS.
Eteri za selulosi zishyirwa mu byiciro hakurikijwe imiterere y'ibisimbuzwa mu bintu birimo anionic, cationic na nonionic. Eteri za nonionic zishobora kugabanywamo ibintu bishonga mu mazi n'ibishonga mu mavuta.
Ibicuruzwa byashyizwe mu nganda biri ku rutonde rw'ibice byo hejuru by'Imbonerahamwe ya 1. Igice cyo hasi cy'Imbonerahamwe ya 1 kigaragaza amwe mu matsinda azwi yo gukwirakwiza etherification, ataraba ibicuruzwa by'ingenzi mu bucuruzi.
Uburyo bwo gusesengura inyuguti zivanze za ether bushobora kwitwa hakurikijwe uburyo zitondekanyije cyangwa urwego rwa DS (MS) zijyanye nabyo, urugero, kuri 2-hydroxyethyl methylcellulose, incamake ni HEMC, kandi ishobora kwandikwa nka MHEC kugira ngo igaragaze inyuguti zisanzwe za methyl.
Amatsinda ya hydroxyl kuri selulosi ntabwo byoroshye kuyabona hakoreshejwe ibikoresho bya etherification, kandi inzira ya etherification ikunze gukorwa mu bihe bya alkaline, muri rusange hakoreshejwe ingano runaka y'umuti wa NaOH. Selulosi ibanza gukorwamo selulosi ya alkali yabyimbye hamwe n'umuti wa NaOH, hanyuma igakora reaction ya etherification hamwe n'umuti wa etherification. Mu gihe cyo gukora no gutegura ethers zivanze, ubwoko butandukanye bw'ibikoresho bya etherification bugomba gukoreshwa icyarimwe, cyangwa etherification igomba gukorwa intambwe ku yindi binyuze mu kugaburira rimwe na rimwe (niba bikenewe). Hari ubwoko bune bw'inyito muri etherification ya selulosi, bukubiye muri formula ya reaction (cellulosic isimburwa na Cell-OH) nk'uko bikurikira:
Ikigereranyo (1) gisobanura uburyo Williamson etherification reaction. RX ni ester ya aside inorganic, naho X ikaba halogen Br, Cl cyangwa ester ya aside sulfurique. Chloride R-Cl ikoreshwa mu nganda, urugero, methyl chloride, ethyl chloride cyangwa aside chloroacetic. Ingano ya stoichiometric y'ibanze ikoreshwa muri ubwo buryo. Ibicuruzwa bya ether bya cellulose byakozwe mu nganda nka methyl cellulose, ethyl cellulose na carboxymethyl cellulose ni ibikomoka kuri Williamson etherification reaction.
Formula ya reaction (2) ni reaction yo kongeramo epoxides za base-catalyzed (nka R=H, CH3, cyangwa C2H5) na hydroxyl groups kuri molecules za cellulose zitarinze gukoresha base. Iyi reaction ishobora gukomeza uko groups nshya za hydroxyl zivuka mu gihe cy'reaction, biganisha ku iremwa ry'imiyoboro ya oligoalkylethylene oxide: Igisubizo nk'iki cya 1-aziridine (aziridine) kizarema aminoethyl ether: Cell-O-CH2-CH2-NH2. Ibicuruzwa nka hydroxyethyl cellulose, hydroxypropyl cellulose na hydroxybutyl cellulose byose ni umusaruro wa epoxidation ya base-catalyzed.
Formula ya reaction (3) ni reaction iri hagati ya Cell-OH n'ibinyabutabire by'umwimerere birimo imigozi ibiri ikora mu buryo bwa alkaline, Y ni itsinda rikuramo electron, nka CN, CONH2, cyangwa SO3-Na+. Muri iki gihe ubu bwoko bw'reaction ntibukunze gukoreshwa mu nganda.
Formula yo gukora reaction (4), etherification hamwe na diazoalkane ntabwo irashyirwa mu bikorwa nk'inganda kugeza ubu.
- Ubwoko bwa ether za selulosi
Eteri ya selulosi ishobora kuba monoether cyangwa ivanze, kandi imiterere yayo iratandukanye. Hari amatsinda ya hydrophilic adasimbuwe cyane kuri macromolecule ya selulosi, nka hydroxyethyl, ashobora guha umusaruro urwego runaka rw'amazi ashongeshwa, mu gihe ku matsinda ya hydrophobic, nka methyl, ethyl, nibindi, gusa insimburangingo iringaniye. Uburemere bwo hejuru bushobora guha umusaruro ubushobozi runaka bwo gushongeshwa mu mazi, kandi umusaruro udasimbuwe cyane urushaho kwiyongera mu mazi cyangwa ushobora gushonga mu gisubizo cya alkali. Hamwe n'ubushakashatsi bwimbitse ku miterere ya eteri za selulosi, eteri nshya za selulosi n'imirima yazo ikoreshwa bizahora bitera imbere kandi bigakorwa, kandi imbaraga nini ni isoko rinini kandi rihora ritunganywa.
Itegeko rusange ry’ingaruka z’amatsinda muri ether zivanze ku miterere y’ishonga ni:
1) Ongera ingano y'amatsinda arwanya amazi mu gicuruzwa kugira ngo wongere ubwiyongere bwa eteri mu mazi no kugabanya ingingo ya gel;
2) Ongera ingano y'amatsinda akunda amazi (nk'amatsinda ya hydroxyethyl) kugira ngo wongere urugero rwa gel yayo;
3) Itsinda rya hydroxypropyl ni umwihariko, kandi hydroxypropylation ikwiye ishobora kugabanya ubushyuhe bwa gel bw'umusaruro, kandi ubushyuhe bwa gel bw'umusaruro uciriritse wa hydroxypropyl buzongera kuzamuka, ariko urwego rwo hejuru rwo gusimbuza ruzagabanya ingingo ya gel; Impamvu ni uko imiterere yihariye y'uburebure bw'umunyururu wa karuboni w'itsinda rya hydroxypropyl, hydroxypropylation yo ku rwego rwo hasi, imigozi ya hydrogen yagabanutse mu nganda no hagati ya molekile muri macromolecule ya cellulose, n'amatsinda ya hydroxyl akunda gusimbuza ku nganda. Amazi ni yo akomeye. Ku rundi ruhande, niba gusimbuza ari byinshi, hazabaho polymerization ku itsinda ryo ku ruhande, ingano y'itsinda rya hydroxyl izagabanuka, hydrophobicity iziyongera, kandi gushonga bizagabanuka ahubwo.
Umusaruro n'ubushakashatsi byaeteri ya seluloseifite amateka maremare. Mu 1905, Suida yatanze bwa mbere raporo ku ihinduka rya selulose, yari ifite methyl hamwe na dimethyl sulfate. Nonionic alkyl ethers zahawe uburenganzira na Lilienfeld (1912), Dreyfus (1914) na Leuchs (1920) ku mvange za selulose zishonga mu mazi cyangwa zishonga mu mavuta. Buchler na Gomberg bakoze selulose ya benzyl mu 1921, carboxymethyl cellulose yakozwe bwa mbere na Jansen mu 1918, naho Hubert akora hydroxyethyl cellulose mu 1920. Mu ntangiriro za 1920, carboxymethylcellulose yagurishijwe mu Budage. Kuva mu 1937 kugeza mu 1938, umusaruro w’inganda za MC na HEC wabonetse muri Leta Zunze Ubumwe za Amerika. Suwede yatangiye gukora EHEC ishonga mu mazi mu 1945. Nyuma ya 1945, umusaruro wa selulose ether wariyongereye cyane mu Burayi bw’Iburengerazuba, muri Leta Zunze Ubumwe za Amerika no mu Buyapani. Mu mpera za 1957, CMC y’Ubushinwa yashyizwe mu bikorwa bwa mbere mu ruganda rwa Shanghai Celluloid. Mu 2004, ubushobozi bw’igihugu cyanjye bwo gukora buzaba toni 30.000 za eteri ionic na toni 10.000 za eteri idafite ionic. Mu 2007, izagera kuri toni 100.000 za eteri ionic na toni 40.000 za eteri idafite ionic. Amasosiyete ahuriweho mu ikoranabuhanga mu gihugu no mu mahanga nayo ahora atera imbere, kandi ubushobozi bwo gukora eteri ikoresha cellulose mu Bushinwa n’urwego rwa tekiniki bihora bitera imbere.
Mu myaka ya vuba aha, imvange nyinshi za cellulose monoethers na ethers zivanze zifite agaciro ka DS gatandukanye, ubukana, ubuziranenge n'imiterere ya rheological byakomeje gutezwa imbere. Kuri ubu, intego y'iterambere mu rwego rwa ethers za cellulose ni ugukoresha ikoranabuhanga rigezweho mu gukora, ikoranabuhanga rishya ryo gutegura, ibikoresho bishya, Ibicuruzwa bishya, ibicuruzwa byiza, n'ibicuruzwa bifite gahunda bigomba gukorwaho ubushakashatsi mu buryo bwa tekiniki.
Igihe cyo kohereza: 28 Mata 2024