1. Structure na ụkpụrụ nkwadebe nke cellulose ether
Ihe osise 1 na-egosi ụdị nhazi nke cellulose ethers. Nke ọ bụla bD-anhydroglucose unit (ngalaba cellulose) na-anọchi otu otu na ọnọdụ C (2), C (3) na C (6), ya bụ, enwere ike ịnwe otu ether atọ. N'ihi njikọ intra-chain na inter-chain hydrogen nkecellulose macromolecules, O siri ike igbari na mmiri na ihe fọrọ nke nta ka ọ bụrụ ihe mgbaze organic niile. Iwebata otu ether site na etherification na-emebi njikọ intramolecular na intermolecular hydrogen, na-eme ka hydrophilicity ya dịkwuo mma, ma na-eme ka ọ dịkwuo mma na mgbasa ozi mmiri.
Ihe mgbakwunye etherified a na-ahụkarị bụ otu alkoxy dị arọ (1 ruo 4 carbon atom) ma ọ bụ otu hydroxyalkyl, nke nwere ike dochie ya site na otu ndị ọzọ na-arụ ọrụ dị ka carboxyl, hydroxyl ma ọ bụ amino otu. Ndị nọchiri anya nwere ike ịbụ otu, abụọ ma ọ bụ karịa ụdị dị iche iche. N'akụkụ agbụ cellulose macromolecular, a na-edochi otu hydroxyl na ọnọdụ C (2), C (3) na C (6) nke nkeji glucose ọ bụla n'ụzọ dị iche iche. N'ikwu okwu n'ụzọ doro anya, cellulose ether n'ozuzu enweghị usoro kemịkalụ doro anya, ma e wezụga ngwaahịa ndị ahụ nke otu ụdị na-anọchi kpamkpam (a na-anọchi otu atọ hydroxyl). Enwere ike iji ngwaahịa ndị a naanị maka nyocha ụlọ nyocha na nyocha, na enweghị uru azụmaahịa.
(a) Nhazi nke akụkụ abụọ anhydroglucose nke cellulose ether molecular chain, R1 ~ R6 = H, ma ọ bụ ihe mgbakwunye organic;
(b) Iberibe yinye molekụla nke carboxymethylhydroxyethyl cellulose, ogo nke nnọchi nke carboxymethyl bụ 0.5, ogo nnọchi nke hydroxyethyl bụ 2.0, na ogo nnọchi nke molar bụ 3.0. Ihe owuwu a na-anọchi anya nkezi ọkwa nnọchi nke otu etherified, mana ndị nọchiri anya ya bụ n'ezie enweghị usoro.
Maka onye nọchiri anya nke ọ bụla, a na-egosipụta mkpokọta etherification site na ogo nke nnọchi DS uru. Oke nke DS bụ 0 ~ 3, nke dabara na nkezi ọnụọgụ hydroxyl dị iche iche nke etherification nọchiri anya na ngalaba anhydroglucose ọ bụla.
Maka ethers hydroxyalkyl cellulose, mmeghachi omume ngbanwe ga-amalite etherification site na otu hydroxyl ọhụrụ efu, na ogo nke nnọchi nwere ike jiri uru MS, ya bụ, ogo ngbanwe nke mgbanwe. Ọ na-anọchi anya ọnụ ọgụgụ mole nke etherifying reactant agbakwunyere na nkeji anhydroglucose ọ bụla. Ihe na-emeghachi omume bụ ethylene oxide na ngwaahịa ahụ nwere nnọchi hydroxyethyl. Na eserese 1, uru MS nke ngwaahịa a bụ 3.0.
N'usoro iwu, enweghị oke oke maka uru MS. Ọ bụrụ na amaara uru DS nke ogo ngbanwe na otu mgbanaka glucose ọ bụla, nkezi yinye ogologo nke eriri akụkụ ether ụfọdụ ndị na-emepụta na-ejikarị akụkụ nke oke (wt%) nke otu etherification dị iche iche (dị ka -OCH3 ma ọ bụ -OC2H4OH) iji nọchite anya ọkwa ngbanwe na ogo kama ụkpụrụ DS na MS. Enwere ike ịgbanwe akụkụ oke nke otu ọ bụla yana uru DS ma ọ bụ MS ya site na ngụkọ dị mfe.
Ọtụtụ ethers cellulose bụ polymers na-agbaze mmiri, ụfọdụ na-esikwa ike n'akụkụ ụfọdụ na ihe mgbaze organic. Cellulose ether nwere njirimara nke arụmọrụ dị elu, ọnụ ala dị ala, nhazi dị mfe, obere nsị na ụdị dịgasị iche iche, na ọchịchọ na ngwa ngwa ka na-agbasawanye. Dị ka onye inyeaka, cellulose ether nwere nnukwu ikike itinye n'ọrụ n'akụkụ dị iche iche nke ụlọ ọrụ. enwere ike nweta MS/DS.
A na-ekewa ethers cellulose dabere na nhazi kemịkalụ nke ihe ndị na-eme ihe n'ime anionic, cationic na nonionic ethers. Enwere ike kewaa nonionic ethers n'ime ngwaahịa mmiri na-agbaze na mmanụ.
A na-edepụta ngwaahịa ndị emepụtara n'elu nke Tebụl 1. Akụkụ ala nke Tebụl 1 depụtara ụfọdụ otu etherification ama ama, nke na-aghọbeghị ngwaahịa azụmahịa dị mkpa.
Enwere ike ịkpọ aha nbibi nke ndị nnọchi ether agwakọta dị ka usoro mkpụrụedemede ma ọ bụ ọkwa nke DS (MS), dịka ọmụmaatụ, maka 2-hydroxyethyl methylcellulose, abbreviation bụ HEMC, enwere ike dee ya dị ka MHEC ka gosi ihe nnọchi anya methyl.
Otu hydroxyl dị na cellulose adịghị adị mfe ịnweta site na ndị ọrụ etherification, na usoro etherification na-emekarị n'okpuru ọnọdụ alkaline, n'ozuzu na-eji ụfọdụ ntinye nke ngwọta mmiri NaOH. A na-ebu ụzọ mepụta cellulose n'ime alkali cellulose fụrụ akpụ na ngwọta mmiri NaOH, wee nweta mmeghachi omume etherification na onye na-ahụ maka etherification. N'oge mmepụta na nkwadebe nke ethers agwakọta, a ga-eji ụdị etherification dị iche iche mee ihe n'otu oge, ma ọ bụ etherification kwesịrị ime nzọụkwụ site na nzọụkwụ site na nri na-adịghị agafe agafe (ọ bụrụ na ọ dị mkpa). Enwere ụdị mmeghachi omume anọ na etherification nke cellulose, nke a na-achịkọta site na usoro mmeghachi omume (cellulosic na-anọchi anya Cell-OH) dị ka ndị a:
Nhazi (1) na-akọwa mmeghachi omume etherification nke Williamson. RX bụ inorganic acid ester, na X bụ halogen Br, Cl ma ọ bụ sulfuric acid ester. Chloride R-Cl na-ejikarị eme ihe na ụlọ ọrụ, dịka ọmụmaatụ, methyl chloride, ethyl chloride ma ọ bụ chloroacetic acid. A na-eri oke stoichiometric nke ntọala na mmeghachi omume ndị dị otú ahụ. Ngwaahịa cellulose ether mepere emepe methyl cellulose, ethyl cellulose na carboxymethyl cellulose bụ ngwaahịa nke mmeghachi omume etherification Williamson.
Usoro mmeghachi omume (2) bụ mgbakwunye mgbakwunye nke epoxides na-akpata catalyzed (dị ka R=H, CH3, ma ọ bụ C2H5) na otu hydroxyl na mkpụrụ ndụ cellulose na-enweghị isi. O yikarịrị ka mmeghachi omume a ga-aga n'ihu ka a na-emepụta ìgwè hydroxyl ọhụrụ n'oge mmeghachi omume ahụ, na-eduga n'ịmepụta ụdọ akụkụ oligoalkylethylene oxide: Mmeghachi omume yiri ya na 1-aziridine (aziridine) ga-eme aminoethyl ether: Cell-O-CH2-CH2-NH2 . Ngwaahịa dị ka hydroxyethyl cellulose, hydroxypropyl cellulose na hydroxybutyl cellulose bụ niile ngwaahịa nke base-catalyzed epioxidation.
Usoro mmeghachi omume (3) bụ mmeghachi omume n'etiti Cell-OH na ogige organic nwere agbụ abụọ na-arụ ọrụ na etiti alkaline, Y bụ otu na-ewepụ elektrọn, dị ka CN, CONH2, ma ọ bụ SO3-Na +. Taa ụdị mmeghachi omume a na-adịkarịghị eji ụlọ ọrụ eme ihe.
Usoro mmeghachi omume (4), etherification na diazoalkane emebebeghị nke ọma.
- Ụdị cellulose ethers
Cellulose ether nwere ike ịbụ monoether ma ọ bụ ngwakọta ether, na ihe onwunwe ya dị iche iche. Enwere obere hydrophilic dị iche iche na cellulose macromolecule, dị ka hydroxyethyl otu, nke nwere ike inye ngwaahịa ahụ na ụfọdụ ogo nke mmiri solubility, ebe maka hydrophobic otu, dị ka methyl, ethyl, wdg, naanị agafeghị oke ngbanwe High ogo nwere ike. nye ngwaahịa a ụfọdụ mmiri solubility, na obere-dochiri ngwaahịa naanị zaa na mmiri ma ọ bụ nwere ike igbari na dilute alkali ngwọta. Site na nyocha miri emi na njirimara nke cellulose ethers, a ga-emepụta ethers cellulose ọhụrụ na mpaghara ngwa ha na-aga n'ihu ma mepụta ya, na nnukwu ike ịkwọ ụgbọala bụ ahịa ngwa ngwa na-anụcharịrị.
Iwu izugbe nke mmetụta nke otu dị na ethers agwakọta na akụrụngwa solubility bụ:
1) Na-abawanye ọdịnaya nke hydrophobic dị iche iche na ngwaahịa iji mee ka hydrophobicity nke ether dịkwuo elu ma belata ebe gel;
2) Mụbaa ọdịnaya nke hydrophilic dị iche iche (dị ka otu hydroxyethyl) iji mee ka ebe gel ya dịkwuo elu;
3) Otu hydroxypropyl dị iche iche, na hydroxypropylation kwesịrị ekwesị nwere ike belata gel okpomọkụ nke ngwaahịa ahụ, na gel okpomọkụ nke ọkara hydroxypropylated ngwaahịa ga-ebili ọzọ, ma ọkwa dị elu nke nnọchi ga-ebelata ihe gel ya; Ihe kpatara ya bụ n'ihi nhazi ogologo ogologo carbon carbon pụrụ iche nke otu hydroxypropyl, hydroxypropylation dị ala, ike ọgwụgwụ hydrogen n'ime na n'etiti ụmụ irighiri ihe dị na cellulose macromolecule, na otu hydrophilic hydroxyl na agbụ alaka. Mmiri na-achị. N'aka nke ọzọ, ọ bụrụ na ngbanwe ahụ dị elu, a ga-enwe polymerization n'akụkụ akụkụ, ọdịnaya ikwu nke ìgwè hydroxyl ga-ebelata, hydrophobicity ga-abawanye, na solubility ga-ebelata kama.
Mmepụta na nyocha nkecellulose ethernwere ogologo akụkọ ihe mere eme. Na 1905, Suida buru ụzọ kọwaa etherification nke cellulose, bụ nke methylated na dimethyl sulfate. Nonionic alkyl ethers bụ nke Lilienfeld (1912), Dreyfus (1914) na Leuchs (1920) kwadoro maka ethers cellulose na-agbaze mmiri ma ọ bụ mmanu, n'otu n'otu. Buchler na Gomberg mepụtara benzyl cellulose na 1921, carboxymethyl cellulose bụ Jansen bụ nke mbụ mepụtara na 1918, Hubert mekwara hydroxyethyl cellulose na 1920. Ná mmalite 1920s, a na-ere carboxymethylcellulose na Germany. Site na 1937 ruo 1938, mmepụta mmepụta nke MC na HEC rụpụtara na United States. Sweden malitere mmepụta EHEC mmiri na-agbaze mmiri na 1945. Mgbe 1945 gasịrị, mmepụta nke cellulose ether gbasaa ngwa ngwa na Western Europe, United States na Japan. Ná ngwụsị nke 1957, China CMC e mbụ tinye n'ime mmepụta na Shanghai Celluloid Factory. N'afọ 2004, ikike mmepụta obodo m ga-abụ tọn 30,000 nke ionic ether na tọn 10,000 nke ether na-abụghị ionic. Na 2007, ọ ga-eru 100,000 tọn ionic ether na 40,000 tọn nke Nonionic ether. Ụlọ ọrụ teknụzụ jikọtara ọnụ na ụlọ na ná mba ọzọ na-apụtakwa mgbe niile, ikike mmepụta nke cellulose ether nke China na ọkwa teknụzụ na-akawanye mma mgbe niile.
N'ime afọ ndị na-adịbeghị anya, ọtụtụ cellulose monoethers na ngwakọta ethers nwere ụkpụrụ DS dị iche iche, viscosities, ịdị ọcha na akụrụngwa rheological na-aga n'ihu. Ka ọ dị ugbu a, a na-elekwasị anya na mmepe na mpaghara cellulose ethers bụ ịnakwere nkà na ụzụ mmepụta ihe dị elu, nkà na ụzụ nkwadebe ọhụrụ, ngwá ọrụ ọhụrụ, ngwaahịa ọhụrụ, ngwaahịa ndị dị elu, na ngwaahịa nhazi kwesịrị nyocha nke ọma.
Oge nzipu: Eprel-28-2024