Ucwaningo Lokulawulwa Kwekhwalithi Ye-Hydroxypropyl Methyl Cellulose

Ngokwesimo samanje sokukhiqizwa kwe-HPMC ezweni lami, izici ezithinta ikhwalithi ye-hydroxypropyl methylcellulose ziyahlaziywa, futhi ngalesi sisekelo, indlela yokuthuthukisa izinga lekhwalithi ye-hydroxypropyl methylcellulose kuxoxwa ngayo futhi kufundwe, ukuze kukhiqizwe.

Amagama angukhiye:i-hydroxypropyl methylcellulose; ikhwalithi; ukulawula; ucwaningo

IHydroxypropyl methylcellulose (HPMC) iyi-cellulose engancibiliki emanzini engeyona i-ionic exutshwe ne-ether eyenziwe ngokotini, ukhuni, futhi yafakwa etherified nge-propylene oxide ne-methyl chloride ngemva kokuvuvukala kwe-alkali. I-Cellulose ether exutshwe yi-Ether eshintshiwe ye-ether eshintshwayo eyodwa inezinto ezihlukile ezingcono kune-monoether yoqobo, futhi ingadlala ukusebenza kwe-cellulose ether ngokugcwele nangokuphelele. Phakathi kwama-ethers amaningi axubile, i-hydroxypropyl methylcellulose ibaluleke kakhulu. Indlela yokulungiselela ukufaka i-propylene oxide ku-alkaline cellulose. I-HPMC yezimboni ingachazwa njengomkhiqizo wendawo yonke. I-degree of substitution of the methyl group (i-DS value) ingu-1.3 kuya ku-2.2, futhi i-molar substitution degree ye-hydroxypropyl ingu-0.1 kuya ku-0.8. Kungabonakala kudatha engenhla ukuthi okuqukethwe kanye nezakhiwo ze-methyl ne-hydroxypropyl ku-HPMC zihlukile, okuholela ku-viscosity yokugcina yomkhiqizo kanye Umehluko wokufana uholela ekuguquguqukeni kwekhwalithi yemikhiqizo eqediwe yamabhizinisi ahlukahlukene okukhiqiza.

I-Hydroxypropyl methylcellulose ikhiqiza okuphuma kwe-ether ngokusebenzisa ukusabela kwamakhemikhali, okunezinguquko ezijulile ekubunjweni kwayo, ukwakheka kanye nezakhiwo, ikakhulukazi ukunyibilika kwe-cellulose, okungahlukahluka ngokuya ngohlobo nenani lamaqembu e-alkyl ethulwe. Thola okuphuma ku-ether okuncibilika emanzini, isixazululo se-alkali esincibilikayo, izinyibilikisi ze-polar (ezifana ne-ethanol, i-propanol) nezinyibilikisi ze-organic non-polar (njenge-benzene, i-ether), ezinweba kakhulu izinhlobo nezinkambu zokusetshenziswa kokuphuma kokuphuma ku-cellulose .

1. Umphumela wenqubo ye-hydroxypropyl methylcellulose alkalization kukhwalithi

Inqubo ye-alkalization isinyathelo sokuqala esigabeni sokusabela sokukhiqizwa kwe-HPMC, futhi ingesinye sezinyathelo ezibucayi kakhulu. Ikhwalithi engokwemvelo yemikhiqizo ye-HPMC inqunywa kakhulu inqubo ye-alkalization, hhayi inqubo ye-etherification, ngoba umphumela we-alkalization uthinta ngqo umphumela we-etherification.

IHydroxypropyl methylcellulose isebenzisana nesisombululo se-alkaline ukwenza i-alkali cellulose, esebenza kakhulu. Ekuphenduleni kwe-etherification, ukusabela okuyinhloko kwe-ejenti ye-etherification ekuvuvukeni, ukungena, kanye nokufakwa kwe-cellulose etherification kanye nezinga lokusabela ohlangothini, ukufana kokusabela kanye nezakhiwo zomkhiqizo wokugcina konke kuhlobene nokwakheka nokwakheka i-alkali cellulose, ngakho-ke isakhiwo kanye nezakhiwo zamakhemikhali ze-alkali cellulose yizinto ezibalulekile zocwaningo ekukhiqizeni i-cellulose ether.

2. Umthelela wezinga lokushisa kwikhwalithi ye-hydroxypropyl methylcellulose

Ekuhlanganiseni okuthile kwesisombululo samanzi se-KOH, inani le-adsorption nedigri yokuvuvukala ye-hydroxypropyl methylcellulose kuya ku-alkali kukhuphuka ngokuncipha kwezinga lokushisa lokusabela. Isibonelo, ukukhishwa kwe-alkali cellulose kuyahlukahluka ngokuya nge-KOH: 15 %, 8% ku-10.°C, kanye no-4.2% ngo-5°C. Indlela yalo mkhuba ukuthi ukwakheka kwe-alkali cellulose kuyinqubo yokusabela exothermic. Njengoba izinga lokushisa likhuphuka, i-adsorption ye-hydroxypropyl methylcellulose ku-alkali Inani liyancishiswa, kodwa ukusabela kwe-hydrolysis ye-alkali cellulose kukhuphuke kakhulu, okungahambisani nokwakhiwa kwe-alkali cellulose. Kungabonakala kulokhu okungenhla ukuthi ukwehlisa izinga lokushisa le-alkalization kulungele ukukhiqizwa kwe-alkali cellulose futhi kuvimbela ukusabela kwe-hydrolysis.

3. Umthelela wezithasiselo kwikhwalithi ye-hydroxypropyl methylcellulose

Kuhlelo lwe-cellulose-KOH-water, isithasiselo-usawoti unomthelela omkhulu ekwakhekeni kwe-alkali cellulose. Lapho ukugcwala kwesisombululo se-KOH kungaphansi kuka-13%, ukufakwa kwe-cellulose ku-alkali akuthintwa ukufakwa kukasawoti we-potassium chloride. Lapho ukugcwala kwesisombululo se-lye kungaphezu kuka-13%, ngemuva kokwengeza i-potassium chloride, ukufakwa okusobala kwe-cellulose ku-alkali I-adsorption iyanda ngokugcwala kwe-potassium chloride, kodwa umthamo we-adsorption usuwonke uyancipha, futhi ukukhanyiswa kwamanzi kuyanda kakhulu, Ukwengezwa kukasawoti ngokuvamile akulungile ku-alkalization nokuvuvukala kwe-cellulose, kodwa usawoti ungavimbela i-hydrolysis futhi ulawule uhlelo Ukuqukethwe kwamanzi mahhala ngaleyo ndlela kuthuthukisa umphumela we-alkalization kanye ne-etherification.

4. Umthelela wenqubo yokukhiqiza kwikhwalithi ye-hydroxypropyl methylcellulose

Njengamanje, amabhizinisi okukhiqiza i-hydroxypropyl methylcellulose ezweni lami asebenzisa kakhulu inqubo yokukhiqiza yendlela yokuncibilikisa. Inqubo yokulungiselela kanye ne-etherification ye-alkali cellulose konke kwenziwa ku-solvent ye-organic engasebenzi, ngakho-ke ukotini ocwengekile wempahla eluhlaza udinga ukugaywa ukuze kutholwe indawo engaphezulu ye-Surface kanye nokusebenza kabusha ukuze kuqinisekiswe ikhwalithi yomkhiqizo oqediwe.

Engeza i-cellulose egayiwe, i-organic solvent nesisombululo se-alkali ku-reactor, futhi usebenzise ukunyakazisa komshini okunamandla ezingeni elithile lokushisa kanye nesikhathi ukuze uthole i-alkali cellulose ene-alkalization efanayo kanye nokuwohloka okuncane. Izinyibilikisi ze-organic dilution (isopropanol, toluene, njll.) zine-inertness ethile, okwenza i-hydroxypropyl methylcellulose ikhiphe ukushisa okufanayo ngesikhathi senqubo yokubunjwa, okubonisa inqubekelaphambili yokukhishwa okuhamba kancane, kuyilapho kunciphisa ukusabela kwe-hydrolysis ye-alkali cellulose ngakolunye uhlangothi. Ikhwalithi ye-alkali cellulose, imvamisa ukugcwala kwe-lye esetshenziswa kulesi sixhumanisi kuphezulu njengo-50%.

Ngemuva kokuthi i-cellulose icwiliswe ku-lye, kutholakala i-alkali cellulose evuvuke ngokugcwele futhi ngokulinganayo. I-lye nge-osmotically ikhukhumeza i-cellulose kangcono, ibeka isisekelo esihle sokusabela kwe-etherification okulandelayo. Izihlambululi ezijwayelekile ikakhulukazi zifaka i-isopropanol, i-acetone, i-toluene, njll. Ukuncibilika kwe-lye, uhlobo lwezimo ezincibilikayo nezinyakazayo yizinto eziyinhloko ezithinta ukwakheka kwe-alkali cellulose. Izingqimba ezingenhla nezingezansi zakhiwe uma kuxutshwa. Ungqimba olungaphezulu lwakhiwe nge-isopropanol namanzi, kanti ungqimba olungezansi lwakhiwe nge-alkali kanye nenani elincane le-isopropanol. I-cellulose ehlakazekile ohlelweni ixhumene ngokugcwele nezingqimba eziwuketshezi ezingaphezulu nezingaphansi ngaphansi kokunyakaziswa kwemishini. I-alkali ohlelweni Ibhalansi yamanzi iyashintsha kuze kube yilapho kwakheka i-cellulose.

Njenge-ether ejwayelekile ye-cellulose engeyona i-ionic exubile, okuqukethwe kwamaqembu e-hydroxypropyl methylcellulose kumaketanga e-macromolecular ahlukene, okungukuthi, isilinganiso sokusabalalisa samaqembu e-methyl kanye ne-hydroxypropyl sihlukile ku-C wendawo ngayinye yendandatho kashukela. Inokuhlakazeka okukhulu nokungahleliwe, okwenza kube nzima ukuqinisekisa ukuzinza kwekhwalithi yomkhiqizo.