1. Ụkpụrụ nhazi na nkwadebe nke cellulose ether
Foto nke 1 na-egosi nhazi nkịtị nke cellulose ethers. Nkeji bD-anhydroglucose ọ bụla (ngaji nke cellulose na-emegharị) na-anọchi otu otu na ọnọdụ C (2), C (3) na C (6), ya bụ, enwere ike ịnwe otu ether atọ. N'ihi njikọ hydrogen dị n'ime yinye na nke dị n'etiti yinye nkemkpụrụ ndụ ihe nketa cellulose, ọ na-esiri ike ịgbaze n'ime mmiri na ihe fọrọ nke nta ka ọ bụrụ ihe mgbaze organic niile. Ntinye nke otu ether site na etherification na-ebibi njikọ hydrogen intramolecular na intermolecular, na-eme ka hydrophilicity ya ka mma, ma na-eme ka ọ na-agbaze nke ukwuu na mmiri media.
Ihe ndị etherified na-ejikarị eme ihe bụ otu alkoxy dị obere (otu ruo atọm carbon anọ) ma ọ bụ otu hydroxyalkyl, nke enwere ike iji otu ọrụ ndị ọzọ dịka carboxyl, hydroxyl ma ọ bụ otu amino dochie ya. Ihe ndị a nwere ike ịbụ otu, abụọ ma ọ bụ karịa ụdị dị iche iche. N'akụkụ yinye macromolecular cellulose, a na-eji otu hydroxyl dị na C(2), C(3) na C(6) nke otu glucose ọ bụla dochie ya n'ogo dị iche iche. N'ikwu ya n'ụzọ doro anya, cellulose ether anaghị enwe usoro kemịkalụ doro anya, ewezuga ngwaahịa ndị otu otu dochie kpamkpam (a na-eji otu hydroxyl atọ niile dochie ha). Enwere ike iji ngwaahịa ndị a naanị maka nyocha na nyocha ụlọ nyocha, ha enweghịkwa uru azụmahịa.
(a) Nhazi izugbe nke nkeji anhydroglucose abụọ nke yinye molekul cellulose ether, R1~R6=H, ma ọ bụ ihe nnọchi organic;
(b) Mpekere carboxymethyl nke agbụ ígwè molekulhydroxyethyl cellulose, ogo nke nnọchi nke carboxymethyl bụ 0.5, ogo nke nnọchi nke hydroxyethyl bụ 2.0, na ogo nke nnọchi nke molar bụ 3.0. Nhazi a na-anọchite anya ọkwa nnọchi nke otu etherified, mana ihe ndị na-anọchi anya ya bụ n'ezie enweghị usoro.
Maka ihe nnọchi ọ bụla, a na-egosipụta mkpokọta etherification site na ogo nke uru DS nnọchi. Oke nke DS bụ 0~3, nke dabara na ọnụọgụ nkezi nke otu hydroxyl nke otu etherification dochie na nkeji anhydroglucose ọ bụla.
Maka hydroxyalkyl cellulose ethers, mmeghachi omume nnọchi ga-amalite etherification site na otu hydroxyl ọhụrụ nwere onwe ha, a pụkwara ịtụle ogo nnọchi site na uru MS, ya bụ, ogo molar nke nnọchi. Ọ na-anọchite anya ọnụọgụ nkezi nke moles nke ihe mmeghachi omume etherifying agbakwunyere na nkeji anhydroglucose ọ bụla. Ihe mmeghachi omume nkịtị bụ ethylene oxide na ngwaahịa ahụ nwere ihe nnọchi hydroxyethyl. Na Foto 1, uru MS nke ngwaahịa ahụ bụ 3.0.
N'echiche, enweghị oke elu maka uru MS. Ọ bụrụ na a mara uru DS nke ogo nnọchi na otu mgbanaka glucose ọ bụla, ogologo nkezi nke yinye akụkụ ether Ụfọdụ ndị nrụpụta na-ejikarị oke oke (wt%) nke otu etherification dị iche iche (dịka -OCH3 ma ọ bụ -OC2H4OH) anọchite anya ọkwa na ogo nnọchi kama ụkpụrụ DS na MS. Enwere ike ịgbanwe oke oke nke otu ọ bụla na uru DS ma ọ bụ MS ya site na ngụkọ dị mfe.
Ọtụtụ n'ime ihe ndị na-eme ka cellulose ethers bụrụ polima ndị na-agbaze mmiri, ụfọdụ na-agbazekwa n'ime ihe ndị na-agbaze organic. Cellulose ether nwere njirimara nke arụmọrụ dị elu, ọnụ ahịa dị ala, nhazi dị mfe, obere nsí na ụdị dị iche iche, ọchịchọ na ojiji ka na-agbasa. Dịka ihe enyemaka, cellulose ether nwere nnukwu ikike itinye n'ọrụ n'ọtụtụ ngalaba ụlọ ọrụ. MS/DS nwere ike nweta ya.
A na-ekewa ether cellulose dịka usoro kemịkalụ nke ihe ndị na-anọchi ya si dị n'ime ether anionic, cationic na nonionic. Enwere ike kewaa ether nonionic ka ọ bụrụ ngwaahịa na-agbaze mmiri na nke na-agbaze mmanụ.
Ngwaahịa ndị e mepụtara n'ụlọ ọrụ mmepụta ihe dị n'elu Tebụl 1. Akụkụ ala nke Tebụl 1 depụtara ụfọdụ otu etherification a ma ama, bụ́ ndị na-aghọbeghị ngwaahịa azụmahịa dị mkpa.
Enwere ike ịkpọ aha usoro mkpirisi nke ihe nnọchi ether agwakọtara dịka usoro mkpụrụedemede ma ọ bụ ọkwa nke DS (MS) si dị, dịka ọmụmaatụ, maka 2-hydroxyethyl methylcellulose, okwu mkpirisi bụ HEMC, enwere ike ide ya dị ka MHEC iji gosipụta ihe nnọchi methyl.
Ndị na-eme ka ihe dị n'ime selulose adịghị mfe ịnweta otu hydroxyl dị na selulose, a na-emekwa usoro etherification n'okpuru ọnọdụ alkaline, na-ejikarị ụfọdụ njupụta nke ihe ngwọta mmiri NaOH. A na-ebu ụzọ mepụta cellulose ahụ ka ọ bụrụ alkali cellulose na-aza aza site na iji ihe ngwọta mmiri NaOH, wee na-eme mmeghachi omume etherification site na ihe nnọchi anya etherification. N'oge mmepụta na nkwadebe nke ethers agwakọtara, a ga-eji ụdị ihe nnọchi anya ether dị iche iche n'otu oge, ma ọ bụghị ya, a ga-eme etherification site na nzọụkwụ site na nri na-adịghị mkpa (ọ bụrụ na ọ dị mkpa). E nwere ụdị mmeghachi omume anọ na etherification nke cellulose, nke a na-achịkọta site na usoro mmeghachi omume (a na-eji Cell-OH dochie cellulosic) dị ka ndị a:
Nha nhata (1) na-akọwa mmeghachi omume etherification nke Williamson. RX bụ ester acid inorganic, X bụkwa halogen Br, Cl ma ọ bụ ester acid sulfuric. A na-ejikarị Chloride R-Cl eme ihe n'ụlọ ọrụ mmepụta ihe, dịka ọmụmaatụ, methyl chloride, ethyl chloride ma ọ bụ chloroacetic acid. A na-eri nnukwu stoichiometric nke ntọala na mmeghachi omume ndị dị otú ahụ. Ngwaahịa ether cellulose ether nke ụlọ ọrụ mmepụta ihe bụ methyl cellulose, ethyl cellulose na carboxymethyl cellulose bụ ngwaahịa nke mmeghachi omume etherification nke Williamson.
Usoro mmeghachi omume (2) bụ mmeghachi omume mgbakwunye nke epoxides ndị a na-eme ka ọ dị ka R=H, CH3, ma ọ bụ C2H5) na otu hydroxyl na molekul cellulose na-erighị isi. Mmeghachi omume a nwere ike ịga n'ihu ka a na-emepụta otu hydroxyl ọhụrụ n'oge mmeghachi omume ahụ, na-eduga na nhazi nke oligoalkyletethylene oxide side chains: Mmeghachi omume yiri nke ahụ na 1-aziridine (aziridine) ga-emepụta aminoethyl ether: Cell-O-CH2-CH2-NH2. Ngwaahịa dịka hydroxyethyl cellulose, hydroxypropyl cellulose na hydroxybutyl cellulose bụ ngwaahịa niile sitere na epoxidation base-catalyzed.
Usoro mmeghachi omume (3) bụ mmeghachi omume dị n'etiti Cell-OH na ihe ndị dị ndụ nwere njikọ abụọ na-arụ ọrụ na mpaghara alkaline, Y bụ otu ndị na-ewepụ elektrọn, dị ka CN, CONH2, ma ọ bụ SO3-Na+. Taa, a naghị eji ụdị mmeghachi omume a eme ihe n'ụlọ ọrụ mmepụta ihe.
Usoro mmeghachi omume (4), etherification na diazoalkane ka emebeghị ka ọ bụrụ ụlọ ọrụ mmepụta ihe.
- Ụdị cellulose ethers
Cellulose ether nwere ike ịbụ monoether ma ọ bụ agwakọta ether, ihe ndị o ji eme ya dịkwa iche. E nwere otu hydrophilic dị obere na cellulose macromolecule, dị ka otu hydroxyethyl, nke nwere ike inye ngwaahịa ahụ oke mmiri ịgbaze, ebe maka otu hydrophobic, dị ka methyl, ethyl, wdg, naanị nnọchi dị ala. Oke dị elu nwere ike inye ngwaahịa ahụ ụfọdụ mmiri ịgbaze, ngwaahịa dị ala na-agbaze naanị na mmiri ma ọ bụ enwere ike ịgbaze ya na ngwọta alkali gbazere agbaze. Site na nyocha miri emi na njirimara nke cellulose ethers, a ga-emepụta ma mepụta cellulose ethers ọhụrụ na ubi ngwa ha mgbe niile, ike kachasị ukwuu bụ ahịa ngwa sara mbara na nke a na-eme ka ọ dị mma mgbe niile.
Iwu izugbe gbasara mmetụta nke otu dị iche iche na ethers agwakọtara na ihe ndị na-agbaze bụ:
1) Mee ka ọdịnaya nke otu hydrophobic dị na ngwaahịa ahụ dịkwuo elu iji mee ka hydrophobic nke ether dịkwuo elu ma belata isi ihe gel;
2) Mee ka ọdịnaya nke otu hydrophilic (dịka otu hydroxyethyl) dịkwuo elu iji mee ka isi ihe gel ya dịkwuo elu;
3) Otu hydroxypropyl pụrụ iche, hydroxypropyl kwesịrị ekwesị nwere ike ibelata okpomọkụ gel nke ngwaahịa ahụ, okpomọkụ gel nke ngwaahịa hydroxypropyl dị n'etiti ga-ebili ọzọ, mana ọkwa dị elu nke nnọchi ga-ebelata isi gel ya; Ihe kpatara ya bụ n'ihi nhazi ogologo carbon pụrụ iche nke otu hydroxypropyl, hydroxypropyl dị ala, njikọ hydrogen adịghị ike n'ime na n'etiti molekul dị na macromolecule cellulose, na otu hydrophilic hydroxyl dị na agbụ alaka. Mmiri dị oke. N'aka nke ọzọ, ọ bụrụ na nnọchi ahụ dị elu, a ga-enwe polymerization n'akụkụ otu ahụ, ọdịnaya dị n'etiti otu hydroxyl ga-ebelata, hydrophobicity ga-abawanye, a ga-ebelatakwa mmiri ara ehi.
Mmepụta na nyocha nkecellulose ethernwere akụkọ ihe mere eme ogologo oge. Na 1905, Suida buru ụzọ kọọ akụkọ gbasara etu cellulose si agbanwe, nke e ji dimethyl sulfate mee ka ọ dị ọcha. Lilienfeld (1912), Dreyfus (1914) na Leuchs (1920) nwere ikike ikike maka cellulose ethers ndị na-agbaze mmiri ma ọ bụ nke na-agbaze mmanụ, n'otu n'otu. Buchler na Gomberg mepụtara benzyl cellulose na 1921, Jansen mepụtara carboxymethyl cellulose na 1918, Hubert emepụtakwara hydroxyethyl cellulose na 1920. Na mbido afọ 1920, a malitere ire ere carboxymethylcellulose na Germany. Site na 1937 ruo 1938, mmepụta ụlọ ọrụ mmepụta ihe nke MC na HEC malitere na United States. Sweden malitere mmepụta EHEC nke na-agbaze mmiri na 1945. Mgbe 1945 gasịrị, mmepụta nke cellulose ether gbasaa ngwa ngwa na Western Europe, United States na Japan. Ná ngwụcha afọ 1957, e tinyere China CMC n'ọrụ mmepụta na Shanghai Celluloid Factory. Ka ọ na-erule afọ 2004, ikike mmepụta nke mba m ga-abụ tọn 30,000 nke ionic ether na tọn 10,000 nke non-ionic ether. Ka ọ na-erule afọ 2007, ọ ga-eru tọn 100,000 nke ionic ether na tọn 40,000 nke Nonionic ether. Ụlọ ọrụ teknụzụ jikọtara ọnụ n'ụlọ na mba ofesi na-apụtakwa mgbe niile, ikike mmepụta cellulose ether na ọkwa teknụzụ nke China na-akawanye mma mgbe niile.
N'afọ ndị na-adịbeghị anya, a na-emepụta ọtụtụ cellulose monoethers na agwakọta ethers nwere ụkpụrụ DS dị iche iche, viscosities, ịdị ọcha na ihe onwunwe rheological. Ugbu a, isi ihe mmepe na ngalaba cellulose ethers bụ ịnakwere teknụzụ mmepụta dị elu, teknụzụ nkwadebe ọhụrụ, akụrụngwa ọhụrụ, ngwaahịa ọhụrụ, ngwaahịa dị elu, na ngwaahịa sistemụ kwesịrị inyocha teknụzụ.
Oge ozi: Eprel-28-2024