Hydroxypropyl Methyl Cellulose Ether Technology

Hydroxypropyl methyl cellulose ether yog ib hom nonpolar cellulose ether soluble hauv dej txias tau los ntawm ntuj cellulose los ntawm alkalization thiab etherification hloov.

Ntsiab lus:hydroxypropyl methylcellulose ether; tshuaj tiv thaiv alkalization; etherification cov tshuaj tiv thaiv

1. Technology

Ntuj cellulose yog insoluble nyob rau hauv dej thiab organic kuab tshuaj, ruaj khov rau lub teeb, tshav kub, acid, ntsev thiab lwm yam chemical media, thiab yuav moistened nyob rau hauv dilute alkali tov los hloov lub nto ntawm cellulose.

Hydroxypropyl methyl cellulose ether yog ib hom uas tsis yog-polar, dej txias-soluble cellulose ether tau los ntawm ntuj cellulose los ntawm alkalization thiab etherification hloov.

2. Lub ntsiab tshuaj tiv thaiv mis

2.1 Cov tshuaj tiv thaiv Alkalization

Muaj ob txoj hauv kev rau cov tshuaj tiv thaiv cellulose thiab sodium hydroxide, uas yog, raws li cov xwm txheej sib txawv los tsim cov tshuaj molecular, R - OH - NaOH; los yog tsim cov hlau cawv sib txuas, R - ONa.

Cov kws tshawb fawb feem ntau ntseeg tias cellulose reacts nrog concentrated alkali los tsim ib yam khoom ruaj khov, thiab xav tias txhua los yog ob pawg piam thaj ua ke nrog ib NaOH molecule (ib pawg qabzib tau ua ke nrog peb NaOH molecules thaum cov tshuaj tiv thaiv tiav).

C6H10O5 + NaOH→C6H10O5 NaOH or C6H10O5 + NaOH→C6H10O4 ONa + H2O

C6H10O5 + NaOH→(C6H10O5 ) 2 NaOH or C6H10O5 + NaOH→C6H10O5 C6H10O4 ONa + H2O

Tsis ntev los no, qee cov kws tshawb fawb ntseeg tias kev sib cuam tshuam ntawm cellulose thiab concentrated alkali yuav muaj ob qho kev cuam tshuam tib lub sijhawm.

Tsis hais txog ntawm cov qauv, cov tshuaj lom neeg ntawm cellulose tuaj yeem hloov pauv tom qab kev txiav txim ntawm cellulose thiab alkali, thiab nws tuaj yeem cuam tshuam nrog ntau yam tshuaj lom neeg kom tau txais hom muaj txiaj ntsig.

2.2 Cov tshuaj tiv thaiv Etherification

Tom qab alkalization, active alkali cellulose reacts nrog etherification tus neeg sawv cev los tsim cellulose ether. Cov tshuaj etherifying siv yog methyl chloride thiab propylene oxide.

Sodium hydroxide ua zoo li catalyst.

n thiab m sawv cev rau qib ntawm kev hloov pauv ntawm hydroxypropyl thiab methyl ntawm cellulose unit, raws li. Qhov siab tshaj plaws ntawm m + n yog 3.

Ntxiv nrog rau cov tshuaj tiv thaiv tseem ceeb saum toj no, kuj tseem muaj cov tshuaj tiv thaiv sab nraud:

CH2CH2OCH3 + H2O→HOCH2CH2OHCH3

CH3Cl + NaOH→CH3OH + NaCl

3. Txheej txheem piav qhia ntawm hydroxypropyl methylcellulose ether

Cov txheej txheem ntawm hydroxypropyl methyl cellulose ether ("cellulose ether" luv luv) yog kwv yees li ntawm 6 txheej txheem, xws li: raw khoom crushing, (alkalinization) etherification, hnyav tshem tawm, pom thiab ziab, crushing thiab sib tov, thiab tiav cov khoom ntim.

3.1 Raw khoom npaj

Lub ntuj luv-lint cellulose yuav nyob rau hauv kev ua lag luam yog crushed rau hauv hmoov los ntawm pulverizer los pab txhawb kev ua tom ntej; cov khoom alkali (los yog kua alkali) yog melted thiab npaj, thiab rhuab mus txog 90°C los ua 50% caustic soda tov rau siv. Npaj cov tshuaj tiv thaiv methyl chloride, propylene oxide etherification tus neeg saib xyuas, isopropanol thiab toluene cov tshuaj tiv thaiv hnyav tib lub sijhawm.

Tsis tas li ntawd, cov txheej txheem tshuaj tiv thaiv yuav tsum muaj cov khoom siv xws li dej kub thiab dej ntshiab; chav dej, dej txias txias, thiab cov dej txias txias yuav tsum tau los pab lub zog.

Cov linter luv, methyl chloride, thiab propylene oxide etherification agents yog cov ntaub ntawv tseem ceeb rau kev tsim etherified cellulose, thiab cov linters luv yog siv ntau heev. Methyl chloride thiab propylene oxide koom nrog cov tshuaj tiv thaiv raws li etherification cov neeg ua haujlwm los hloov cov cellulose ntuj, tus nqi ntawm kev siv tsis loj.

Cov kuab tshuaj (los yog diluents) feem ntau muaj xws li toluene thiab isopropanol, uas yog qhov pib tsis tau noj, tab sis nyob rau hauv qhov kev pom ntawm entrained thiab volatilized poob, muaj me ntsis poob rau hauv ntau lawm, thiab tus nqi siv tsawg heev.

Cov txheej txheem npaj cov khoom siv raw khoom muaj thaj chaw raw khoom tank thiab ib qho khoom siv raw khoom txuas nrog. Etherifying cov neeg ua haujlwm thiab cov kuab tshuaj, xws li toluene, isopropanol, thiab acetic acid (siv los kho pH tus nqi ntawm cov reactants), yog khaws cia rau hauv cov khoom siv raw khoom tank. Cov khoom ntawm luv luv lint yog txaus, tuaj yeem muab los ntawm kev ua lag luam txhua lub sijhawm.

Lub crushed luv luv lint raug xa mus rau lub rooj cob qhia nrog lub laub siv.

3.2 (Alkalinization) etherification

(Alkaline) etherification yog txheej txheem tseem ceeb hauv cov txheej txheem ntawm etherification ntawm cellulose. Nyob rau hauv txoj kev tsim khoom ua ntej, ob-kauj ruam cov tshuaj tiv thaiv tau muab cais tawm. Tam sim no cov txheej txheem tau txhim kho, thiab ob-kauj ruam cov tshuaj tiv thaiv tau ua ke hauv ib theem thiab ua tiav ib txhij.

Ua ntej, nqus lub tank etherification kom tshem tawm cov huab cua, thiab tom qab ntawd hloov nrog nitrogen kom lub tank tsis muaj cua. Ntxiv cov tshuaj sodium hydroxide npaj, ntxiv ib qho nyiaj ntawm isopropanol thiab toluene hnyav, pib nplawm, tom qab ntawd ntxiv cov paj rwb luv luv, tig rau cov dej ntws kom txias, thiab tom qab qhov kub thiab txias poob rau ib theem, tig rau qis- Cov dej kub kom txo cov khoom siv kub poob mus txog li 20℃, thiab tuav cov tshuaj tiv thaiv rau ib lub sij hawm ntawm kev ua kom tiav alkalization.

Tom qab alkalization, ntxiv etherifying tus neeg sawv cev methyl chloride thiab propylene oxide ntsuas los ntawm qib siab metering tank, txuas ntxiv pib nplawm, siv chav ua kom lub cev kub kom ze li 70.℃~ 80℃, thiab tom qab ntawd siv cov dej kub txuas ntxiv kom sov thiab tswj xyuas qhov ntsuas kub ntawm cov tshuaj tiv thaiv, thiab tom qab ntawd cov tshuaj tiv thaiv kub thiab cov tshuaj tiv thaiv lub sijhawm raug tswj, thiab kev ua haujlwm tuaj yeem ua tiav los ntawm kev nplawm thiab sib tov rau qee lub sijhawm.

Cov tshuaj tiv thaiv yog nqa tawm ntawm txog 90°C thiab 0.3 MPa.

3.3 Desolvation

Cov ntaub ntawv uas tau hais los saum toj no raug xa mus rau lub desolventizer, thiab cov ntaub ntawv raug stripped thiab rhuab nrog chav, thiab cov toluene thiab isopropanol cov kuab tshuaj yog evaporated thiab zoo rov qab rau kev rov ua dua.

Cov evaporated hnyav yog thawj zaug txias thiab ib nrab condensed nrog circulating dej, thiab ces condensed nrog tsawg-kub dej, thiab cov condensate sib tov nkag mus rau hauv cov kua txheej thiab cais cais cov dej thiab hnyav. Cov kuab tshuaj sib xyaw ntawm toluene thiab isopropanol nyob rau hauv cov txheej txheej sab saud yog kho hauv kev faib ua feem. Siv nws ncaj qha, thiab xa rov qab cov dej thiab isopropanol tov nyob rau hauv qis txheej mus rau lub desolventizer siv.

Ntxiv acetic acid rau cov reactant tom qab desolvation rau neutralize ntau tshaj sodium hydroxide, ces siv dej kub los ntxuav cov khoom, ua kom tag nrho cov coagulation yam ntxwv ntawm cellulose ether rau dej kub ntxuav cellulose ether, thiab refine lub reactant. Cov ntaub ntawv ua kom zoo raug xa mus rau cov txheej txheem tom ntej rau kev sib cais thiab ziab.

3.4 Lim thiab qhuav

Cov khoom siv ua kom zoo yog xa mus rau kab rov tav ntsia hlau cais los ntawm cov twj tso kua mis siab siab kom cais cov dej dawb, thiab cov khoom seem ntxiv nkag mus rau hauv lub tshuab ziab khaub ncaws los ntawm cov ntsia hlau feeder, thiab qhuav hauv kev sib cuag nrog cua kub, thiab tom qab ntawd dhau los ntawm cua daj cua dub. separator thiab huab cua Sib cais, cov khoom siv nkag mus rau tom ntej crushing.

Cov dej sib cais los ntawm kab rov tav kauv separator nkag mus rau hauv lub tank kho dej tom qab sedimentation hauv lub tank sedimentation cais cov cellulose entrained.

3.5 Crushing thiab sib tov

Tom qab ziab, cov etherified cellulose yuav muaj qhov loj me me, uas yuav tsum tau crushed thiab sib tov kom cov particle loj tis thiab tag nrho cov tsos ntawm cov khoom raws li cov khoom txheem.

3. 6 Kev ntim khoom tiav

Cov khoom tau txais tom qab crushing thiab sib tov ua hauj lwm yog cov tiav etherified cellulose, uas yuav muab ntim thiab muab tso rau hauv cia.

4. Cov ntsiab lus

Cov dej khib nyiab sib cais muaj qee cov ntsev, feem ntau yog sodium chloride. Cov dej khib nyiab yog evaporated kom cais cov ntsev, thiab cov evaporated thib ob chav tuaj yeem ua kom rov qab tau cov dej condensed, los yog tawm ncaj qha. Cov ntsiab lus tseem ceeb ntawm cov ntsev sib cais yog sodium chloride, uas kuj muaj qee yam ntawm sodium acetate vim yog qhov tsis zoo nrog acetic acid. Cov ntsev no muaj txiaj ntsig kev lag luam tsuas yog tom qab recrystallization, sib cais thiab purification.