Feem ntau, nyob rau hauv lub synthesis ntawmHydroxypropyl methylcellulose yog ib qho khoom siv zoo, cov paj rwb refined cellulose yog kho nrog alkali tov ntawm 35-40 ° C rau ib nrab ib teev, nyem, lub cellulose yog pulverized, thiab tsim nyog hnub nyoog ntawm 35 ° C, thiaj li hais tias cov alkali fibers tau nruab nrab polymerized degree nyob rau hauv qhov yuav tsum tau. ntau. Muab cov alkali fiber ntau tso rau hauv etherification kettle, ntxiv propylene oxide thiab methyl chloride nyob rau hauv lem, thiab etherify ntawm 50-80 ℃ rau 5 teev mus rau ib tug siab ntawm txog 1.8 MPa. Tom qab ntawd ntxiv qhov tsim nyog ntawm hydrochloric acid thiab oxalic acid rau hauv dej kub ntawm 90 ° C los ntxuav cov khoom kom nthuav dav. Dehydrate nrog lub centrifuge. Ntxuav kom txog thaum nruab nrab, thaum cov dej hauv cov khoom muaj tsawg dua 60%, ziab nws nrog cua kub ntws ntawm 130 ° C mus rau tsawg dua 5%.
Alkalization: Cov hmoov refined paj rwb tom qab qhib tau ntxiv rau hauv cov kuab tshuaj inert, thiab qhib nrog alkali thiab cov dej mos kom swell cov siv lead ua lattice ntawm cov paj rwb refined, uas yog qhov zoo rau kev nkag mus ntawm etherifying tus neeg sawv cev molecules thiab txhim kho cov uniformity ntawm etherification cov tshuaj tiv thaiv. . Cov alkali siv nyob rau hauv alkalization yog hlau hydroxide los yog organic puag. Tus nqi ntawm alkali ntxiv (los ntawm huab hwm coj, tib yam hauv qab no) yog 0.1-0.6 npaug ntawm cov paj rwb refined, thiab cov dej mos yog 0.3-1.0 npaug ntawm cov paj rwb refined; lub inert hnyav yog sib tov ntawm cawv thiab hydrocarbon, thiab tus nqi ntawm inert hnyav ntxiv yog refined paj rwb. 7-15 zaug: cov kuab tshuaj inert kuj tuaj yeem yog cawv nrog 3-5 carbon atoms (xws li cawv, propanol), acetone. Nws tuaj yeem yog aliphatic hydrocarbons thiab muaj ntxhiab hydrocarbons; kub yuav tsum tau tswj nyob rau hauv 0-35 ° C thaum lub sij hawm alkalization; Lub sijhawm alkalization yog li 1 teev. Kev hloov pauv ntawm qhov kub thiab lub sijhawm tuaj yeem txiav txim siab raws li qhov xav tau ntawm cov khoom siv thiab cov khoom.
Etherification: Tom qab kev kho alkalization, nyob rau hauv lub tshuab nqus tsev, etherification yog ua los ntawm kev ntxiv tus neeg sawv cev etherifying, thiab tus neeg sawv cev etherifying yog propylene oxide. Txhawm rau txo qis kev noj ntawm tus neeg sawv cev etherifying, tus neeg sawv cev etherifying tau ntxiv ob zaug thaum lub sijhawm etherification txheej txheem.
Lub sij hawm xa tuaj: Plaub Hlis-28-2024