Hydroxypropyl methylcellulose (HPMC) ke motsoako oa bohlokoa oa semi-synthetic cellulose ether, o sebelisoang haholo meriana, thepa ea mohaho, lijo, liphahlo le liindasteri tse ling. HPMC e na le botenya bo botle, emulsification, ho etsa filimi, ho nosetsa, ho tsitsisa le thepa e 'ngoe, kahoo e na le bohlokoa ba kopo ea bohlokoa likarolong tse ngata. Lisebelisoa tsa mantlha tsa tlhahiso ea HPMC li kenyelletsa cellulose, sodium hydroxide, propylene oxide, methyl chloride le metsi.
1. Cellulose
Cellulose ke thepa e tala ea mantlha ea HPMC, hangata e nkiloeng ho likhoele tsa tlhaho tsa semela joalo ka k'hothone le patsi. Cellulose ke polymer ea tlhaho e ngata ka ho fetisisa lefatšeng. Sebopeho sa eona sa molek'hule ke polysaccharide e telele e entsoeng ka likaroloana tsa tsoekere tse kopantsoeng ke li-bond β-1,4-glycosidic. Cellulose ka boeona ha e qhibilihe ka metsing 'me ha e na lik'hemik'hale tse ntle tsa lik'hemik'hale. Ka hona, ho hlokahala letoto la mekhoa ea ho fetola lik'hemik'hale ho ntlafatsa ho qhibiliha ha eona le ho sebetsa ha eona ho lokisa lihlahisoa tse fapaneng tsa cellulose ether.
2. Sodium hydroxide (NaOH)
Sodium hydroxide, e tsejoang hape e le caustic soda, ke motsoako o matla oa alkaline o phethang karolo ea bohlokoa joalo ka alkalizer ts'ebetsong ea tlhahiso ea HPMC. Mothating oa pele oa tlhahiso, cellulose e sebetsana le tharollo ea sodium hydroxide ho kenya tšebetsong lihlopha tsa hydroxyl ho ketane ea limolek'hule tsa cellulose, ka hona e fana ka libaka tsa karabelo bakeng sa karabelo e latelang ea etherification. Mohato ona o boetse o bitsoa "alkalization reaction". Alkalized cellulose e ba le liphetoho tse itseng tsa sebopeho, ho etsa hore ho be bonolo ho sebetsana le li-reagents tsa lik'hemik'hale tse latelang (tse kang propylene oxide le methyl chloride).
3. Propylene oxide (C3H6O)
Propylene oxide ke e 'ngoe ea lisebelisoa tsa bohlokoa tsa etherifying tlhahiso ea HPMC, e sebelisoang haholo ho fetolela lihlopha tsa hydroxyl ka selulose hore e be lihlopha tsa hydroxypropyl. Ka ho khetheha, selulose ea alkalized e sebetsa le propylene oxide tlas'a maemo a itseng a mocheso le khatello, 'me lihlopha tse sebetsang tsa epoxy ka propylene oxide li hokahane le ketane ea molek'hule ea cellulose ka karabelo ea ho bula lesale ho etsa motsoako oa hydroxypropyl. Ts'ebetso ena e fana ka HPMC e ntle ea ho qhibiliha ha metsi le bokhoni ba ho tenya.
4. Methyl chloride (CH3Cl)
Methyl chloride ke ntho e 'ngoe ea bohlokoa ea etherifying e sebelisoang ho fetolela lihlopha tsa hydroxyl tsa selulose hore e be lihlopha tsa methoxyl. Methyl chloride e sebetsana le lihlopha tsa hydroxyl ho ketane ea limolek'hule tsa cellulose ka karabelo ea sebaka sa nucleophilic ho hlahisa methyl cellulose. Ka karabelo ena ea methylation, HPMC e fumana hydrophobicity e ntle, haholo-holo e bonts'a ho qhibiliha ho hoholo ho tse ling tsa manyolo. Ho phaella moo, ho kenyelletsoa ha lihlopha tsa methoxy ho tsoela pele ho ntlafatsa thepa ea ho etsa lifilimi le botsitso ba lik'hemik'hale tsa HPMC.
5. Metsi
Metsi, joalo ka mokelikeli le mokhoa oa ho arabela, a tsamaisana le ts'ebetso eohle ea tlhahiso ea HPMC. Karabelong ea alkalization le etherification, metsi ha a thuse feela ho qhala sodium hydroxide le ho lokisa boemo ba hydration ea cellulose, empa hape a nka karolo taolong ea mocheso o arabelang ho netefatsa taolo ea mocheso nakong eohle ea karabelo. Ho hloeka ha metsi ho na le tšusumetso ea bohlokoa ho boleng ba HPMC, 'me metsi a hloekileng a hloekileng haholo kapa metsi a hloekisitsoeng hangata a hlokahala.
6. Li-solvents tsa tlhaho
Ts'ebetsong ea tlhahiso ea HPMC, mehato e meng ea ts'ebetso e kanna ea hloka ts'ebeliso ea metsoako e meng ea tlhaho, joalo ka methanol kapa ethanol. Ka linako tse ling li-solvents tsena li sebelisoa ho lokisa viscosity ea sistimi ea karabelo, ho fokotsa sebopeho sa li-reaction by-products, kapa ho khothaletsa tšebetso e itseng ea lik'hemik'hale. Khetho ea mokelikeli oa tlhaho o hloka ho khethoa ho latela litlhoko tsa ts'ebetso ea tlhahiso le ts'ebeliso ea sehlahisoa sa ho qetela.
7. Lisebelisoa tse ling tse thusang
Ntle le lisebelisoa tse tala tse kaholimo, ts'ebetsong ea 'nete ea tlhahiso, lisebelisoa tse ling tse thusang le li-additives, joalo ka li-catalysts, stabilizers, joalo-joalo, li ka sebelisoa ho ntlafatsa ts'ebetso ea karabelo, ho laola sekhahla sa karabelo kapa ho ntlafatsa thepa ea' mele le ea lik'hemik'hale. ea sehlahisoa sa ho qetela.
8. Mehato e ka sehloohong ea ts'ebetso ea tlhahiso
Mehato ea mantlha ea ho hlahisa HPMC e ka aroloa likarolo tse tharo: kalafo ea alkalization, etherification le neutralization. Taba ea pele, selulose e kopana le sodium hydroxide ho alkalize ho etsa alkali cellulose. Joale, etherification e etsahala karabelong ea alkali cellulose e nang le propylene oxide le methyl chloride ho theha hydroxypropyl le methoxy substituted cellulose ethers. Qetellong, ka phekolo ea neutralization, ho hlatsoa, ho omisa le mekhoa e meng, lihlahisoa tsa HPMC tse nang le solubility e khethehileng, viscosity le litšobotsi tse ling li fumanoa.
9. Phello ea boleng ba thepa e tala ts'ebetsong ea lihlahisoa tsa HPMC
Mehloli e fapaneng ea lisebelisoa tse tala le bohloeki li na le tšusumetso e kholo ho boleng le ts'ebetso ea HPMC ea ho qetela. Mohlala, bohloeki le kabo ea boima ba limolek'hule ea lisebelisoa tse tala tsa cellulose e tla ama viscosity le solubility ea HPMC; maemo a litekanyetso le a karabelo ea propylene oxide le methyl chloride e tla etsa qeto ea tekanyo ea hydroxypropyl le methoxy substitution, kahoo e ama phello e teteaneng le thepa ea ho etsa filimi ea sehlahisoa. Ka hona, khetho le taolo ea boleng ba thepa e tala li bohlokoa nakong ea tlhahiso.
Lisebelisoa tsa mantlha tsa hydroxypropyl methylcellulose (HPMC) li kenyelletsa selulose, sodium hydroxide, propylene oxide, methyl chloride le metsi. Ka letoto la liphetoho tse rarahaneng tsa lik'hemik'hale, lisebelisoa tsena tse tala li fetoloa lisebelisoa tse sebetsang tse nang le boleng bo pharaletseng ba tšebeliso. Lenane la ts'ebeliso ea HPMC le akaretsa masimo a mangata joalo ka meriana, thepa ea moaho le lijo. Lintho tsa eona tse ntle tsa 'mele le tsa lik'hemik'hale li etsa hore e be ea bohlokoa haholo liindastering tse ngata.
Nako ea poso: Sep-30-2024