Etherification cov tshuaj tiv thaiv ntawm cellulose ether

Kev ua haujlwm etherification ntawm cellulose tau kawm los ntawm lub tshuab kneading thiab stirring reactor feem, thiab hydroxyethyl cellulose thiab carboxymethyl cellulose tau npaj los ntawm chloroethanol thiab monochloroacetic acid feem. Cov txiaj ntsig tau pom tias cov tshuaj tiv thaiv etherification ntawm cellulose tau ua los ntawm nplawm reactor nyob rau hauv cov xwm txheej ntawm kev kub ntxhov siab. Cellulose muaj qhov zoo etherification reactivity, uas yog zoo dua li txoj kev kneader hauv kev txhim kho etherification efficiency thiab txhim khu lub teeb kis tau tus mob ntawm cov khoom nyob rau hauv aqueous tov.) Yog li ntawd, kev txhim kho cov stirring siv ntawm cov tshuaj tiv thaiv txheej txheem yog ib tug zoo dua txoj kev los tsim hloov homogeneous cellulose etherification. cov khoom.

Cov lus tseem ceeb:etherification cov tshuaj tiv thaiv; Cellulose;Hydroxyethyl cellulose; Carboxymethyl cellulose

Hauv kev txhim kho cov khoom ua kom zoo nkauj paj rwb cellulose ether, cov txheej txheem hnyav yog dav siv thiab kneading tshuab yog siv los ua cov khoom siv tshuaj tiv thaiv. Txawm li cas los xij, paj rwb cellulose feem ntau yog tsim los ntawm cov siv lead ua thaj chaw uas cov molecules tau teeb tsa kom zoo thiab zoo. Thaum lub tshuab kneading yog siv los ua cov khoom siv tshuaj tiv thaiv, lub kneading caj npab ntawm lub tshuab kneading qeeb thaum lub sij hawm cov tshuaj tiv thaiv, thiab cov kev tiv thaiv ntawm etherifying tus neeg saib xyuas nkag mus rau txawv khaubncaws sab nraud povtseg ntawm cellulose yog loj thiab ceev yog qeeb, ua rau lub sij hawm ntev cov tshuaj tiv thaiv, siab feem ntawm sab. cov tshuaj tiv thaiv thiab tsis sib npaug ntawm cov pab pawg hloov pauv ntawm cellulose molecular chains.

Feem ntau cov tshuaj tiv thaiv etherification ntawm cellulose yog cov tshuaj tiv thaiv heterogeneous sab nraud thiab sab hauv. Yog tias tsis muaj kev cuam tshuam sab nraud, tus neeg sawv cev etherifying yog qhov nyuaj rau nkag mus rau thaj tsam crystallization ntawm cellulose. Thiab los ntawm pretreatment ntawm refined paj rwb (xws li siv lub cev txoj kev los ua kom cov nto ntawm refined paj rwb), nyob rau tib lub sij hawm nrog stirring reactor rau cov khoom siv tshuaj tiv thaiv, siv ceev nrooj stirring etherification cov tshuaj tiv thaiv, raws li kev xav, cellulose muaj zog o, o. ntawm cellulose amorphous cheeb tsam thiab crystallization cheeb tsam yuav zoo ib yam, txhim kho cov tshuaj tiv thaiv kev ua si. Lub homogeneous tis ntawm cellulose ether substituents nyob rau hauv heterogeneous etherification cov tshuaj tiv thaiv kab mob tuaj yeem ua tiav los ntawm kev nce lub zog sab nraud. Yog li nws yuav yog txoj kev loj hlob yav tom ntej ntawm peb lub teb chaws los tsim cov khoom lag luam zoo cellulose etherification nrog stirred hom tshuaj tiv thaiv kettle li cov khoom siv tshuaj tiv thaiv.

1. Kev sim ib feem

1.1 Refined paj rwb cellulose raw khoom rau kev kuaj

Raws li cov khoom siv sib txawv siv hauv kev sim, cov txheej txheem pretreatment ntawm paj rwb cellulose yog txawv. Thaum lub kneader yog siv los ua cov khoom siv tshuaj tiv thaiv, cov txheej txheem pretreatment kuj txawv. Thaum lub kneader yog siv los ua cov khoom siv tshuaj tiv thaiv, lub crystallinity ntawm refined paj rwb cellulose siv yog 43.9%, thiab qhov nruab nrab ntev ntawm refined paj rwb cellulose yog 15 ~ 20mm. Lub crystallinity ntawm refined paj rwb cellulose yog 32.3% thiab qhov nruab nrab ntev ntawm refined paj rwb cellulose yog tsawg tshaj li 1 hli thaum stirring reactor yog siv los ua cov khoom siv tshuaj tiv thaiv.

1.2 Kev loj hlob ntawm carboxymethyl cellulose thiab hydroxyethyl cellulose

Kev npaj ntawm carboxymethyl cellulose thiab hydroxyethyl cellulose tuaj yeem ua tiav los ntawm kev siv 2L kneader ua cov khoom siv tshuaj tiv thaiv (qhov nruab nrab ceev thaum cov tshuaj tiv thaiv yog 50r / min) thiab 2L stirring reactor ua cov khoom siv tshuaj tiv thaiv (qhov nruab nrab ceev thaum lub sij hawm cov tshuaj tiv thaiv yog 500r / min).

Thaum lub sij hawm cov tshuaj tiv thaiv, tag nrho cov ntaub ntawv raw yog muab los ntawm cov tshuaj tiv thaiv nruj heev. Cov khoom tau los ntawm cov tshuaj tiv thaiv yog ntxuav nrog w = 95% ethanol, thiab tom qab ntawd qhuav los ntawm lub tshuab nqus tsev rau 24h nyob rau hauv qhov tsis zoo siab ntawm 60 ℃ thiab 0.005mpa. Cov ntsiab lus noo noo ntawm cov qauv tau txais yog w = 2.7% ± 0.3%, thiab cov qauv khoom siv rau kev tshuaj xyuas yog ntxuav kom txog thaum cov hmoov tshauv w < 0.2%.

Kev npaj cov kauj ruam ntawm kneading tshuab raws li cov khoom siv tshuaj tiv thaiv yog raws li hauv qab no:

Etherification cov tshuaj tiv thaiv → khoom ntxuav → ziab → grated granulation → ntim yog nqa tawm hauv kneader.

Cov kauj ruam npaj ntawm stirring reactor li cov khoom siv tshuaj tiv thaiv yog raws li nram no:

Etherification cov tshuaj tiv thaiv → khoom ntxuav → ziab thiab granulation → ntim yog nqa tawm nyob rau hauv ib tug stirred reactor.

Nws tuaj yeem pom tau tias lub tshuab kneader yog siv los ua cov khoom siv tshuaj tiv thaiv rau kev npaj cov yam ntxwv ntawm cov tshuaj tiv thaiv qis, ziab thiab sib tsoo granulation kauj ruam los ntawm kauj ruam, thiab qhov zoo ntawm cov khoom yuav txo qis hauv kev sib tsoo.

Cov yam ntxwv ntawm cov txheej txheem npaj nrog stirred reactor raws li cov khoom siv tshuaj tiv thaiv yog raws li hauv qab no: cov tshuaj tiv thaiv kev ua haujlwm siab, cov khoom granulation tsis siv cov txheej txheem granulation txheej txheem ntawm kev ziab thiab sib tsoo, thiab ziab thiab granulation txheej txheem yog nqa tawm tib lub sijhawm nrog cov khoom undried tom qab ntxuav, thiab cov khoom zoo tseem tsis hloov nyob rau hauv qhuav thiab granulation txheej txheem.

1.3 X-ray diffraction tsom xam

X-ray diffraction tsom xam tau ua los ntawm Rigaku D / max-3A X-ray diffractometer, graphite monochromator, Θ lub kaum sab xis yog 8 ° ~ 30 °, CuKα ray, raj siab thiab raj ntws yog 30kV thiab 30mA.

1.4 Infrared spectrum tsom xam

Spectrum-2000PE FTIR infrared spectrometer tau siv rau kev tsom xam infrared spectrum. Tag nrho cov qauv rau kev tsom xam infrared spectrum muaj qhov hnyav ntawm 0.0020g. Cov qauv no tau muab sib xyaw nrog 0.1600g KBr, feem, thiab tom qab ntawd nias (nrog lub thickness ntawm <0.8mm) thiab soj ntsuam.

1.5 Transmittance nrhiav pom

Lub transmittance tau kuaj pom los ntawm 721 spectrophotometer. CMC tov w = w1% tau muab tso rau hauv 1cm colorimetric phaj ntawm 590nm wavelength.

1.6 Degree ntawm kev hloov kho kom pom

HEC hloov qib ntawm hydroxyethyl cellulose yog ntsuas los ntawm cov qauv tshuaj ntsuam xyuas. Lub hauv paus ntsiab lus yog tias HEC tuaj yeem decomposed los ntawm HI hydroiodate ntawm 123 ℃, thiab qib ntawm kev hloov HEC tuaj yeem paub los ntawm kev ntsuas cov khoom decomposed ethylene thiab ethylene iodide tsim. Lub degree ntawm kev hloov ntawm hydroxymethyl cellulose kuj tuaj yeem kuaj los ntawm cov qauv tshuaj ntsuam xyuas cov txheej txheem.

2. Cov txiaj ntsig thiab kev sib tham

Ob hom tshuaj tiv thaiv kettle yog siv ntawm no: ib qho yog kneading tshuab raws li cov khoom siv tshuaj tiv thaiv, lwm yam yog nplawm hom tshuaj tiv thaiv kettle raws li cov khoom siv tshuaj tiv thaiv, nyob rau hauv heterogeneous cov tshuaj tiv thaiv kab mob, alkaline mob thiab dej cawv cawv system, etherification cov tshuaj tiv thaiv ntawm refined paj rwb cellulose yog kawm. Ntawm lawv, cov yam ntxwv thev naus laus zis ntawm lub tshuab kneading raws li cov khoom siv tshuaj tiv thaiv yog: Hauv cov tshuaj tiv thaiv, lub kneading caj npab ceev yog qeeb, lub sij hawm cov tshuaj tiv thaiv ntev, qhov feem ntawm sab kev xav yog siab, qhov kev siv tus nqi ntawm etherifying tus neeg sawv cev yog tsawg, thiab cov uniformity ntawm hloov pab pawg faib nyob rau hauv etherizing cov tshuaj tiv thaiv yog tsis zoo. Cov txheej txheem tshawb fawb tsuas yog txwv tsis pub muaj cov tshuaj tiv thaiv nqaim xwb. Tsis tas li ntawd, kev hloov kho thiab kev tswj hwm ntawm cov tshuaj tiv thaiv tseem ceeb (xws li da dej piv, alkali concentration, kneading caj npab ceev ntawm lub tshuab kneading) tsis zoo heev. Nws yog qhov nyuaj rau kev ua tiav qhov kwv yees sib xws ntawm cov tshuaj tiv thaiv etherification thiab kawm txog kev hloov pauv loj thiab nkag mus rau cov txheej txheem etherification cov tshuaj tiv thaiv hauv qhov tob. Cov txheej txheem ntawm stirring reactor raws li cov khoom siv tshuaj tiv thaiv yog: nrawm nrawm nrawm hauv cov tshuaj tiv thaiv, cov tshuaj tiv thaiv ceev ceev, kev siv tus nqi siab ntawm etherizing tus neeg sawv cev, kev faib tawm ntawm etherizing substituents, adjustable thiab controllable lub ntsiab cov tshuaj tiv thaiv.

Carboxymethyl cellulose CMC tau npaj los ntawm cov khoom siv tshuaj tiv thaiv kneader thiab nplawm cov khoom siv tshuaj tiv thaiv reactor feem. Thaum lub tshuab kneader tau siv los ua cov khoom siv tshuaj tiv thaiv, qhov sib xyaw ua ke yog tsawg thiab qhov nruab nrab kev sib hloov ceev yog 50r / min. Thaum lub stirring reactor tau siv los ua cov khoom siv tshuaj tiv thaiv, qhov sib xyaw ua ke yog siab thiab qhov nruab nrab kev sib hloov ceev yog 500r / min. Thaum cov molar piv ntawm monochloroacetic acid rau cellulose monosaccharide yog 1: 5: 1, lub sij hawm tshuaj tiv thaiv yog 1.5h ntawm 68 ℃. Lub teeb xa hluav taws xob ntawm CMC tau los ntawm lub tshuab kneading yog 98.02% thiab etherification efficiency yog 72% vim qhov zoo permeability ntawm CM hauv chloroacetic acid etherifying tus neeg sawv cev. Thaum lub stirring reactor tau siv los ua cov khoom siv tshuaj tiv thaiv, qhov permeability ntawm tus neeg sawv cev etherifying tau zoo dua, kev xa tawm ntawm CMC yog 99.56%, thiab cov tshuaj tiv thaiv etherizing tau nce mus rau 81%.

Hydroxyethyl cellulose HEC tau npaj nrog kneader thiab nplawm reactor ua cov khoom siv tshuaj tiv thaiv. Thaum kneader tau siv los ua cov khoom siv tshuaj tiv thaiv, cov tshuaj tiv thaiv kev ua haujlwm ntawm etherizing tus neeg sawv cev yog 47% thiab dej solubility tsis zoo thaum lub permeability ntawm chloroethyl cawv etherizing tus neeg saib xyuas tsis zoo thiab cov molar ratio ntawm chloroethanol rau cellulose monosaccharide yog 3: 1 ntawm 60 ℃ rau 4h. . Tsuas yog thaum molar piv ntawm chloroethanol rau cellulose monosaccharides yog 6: 1, cov khoom tuaj yeem tsim cov dej zoo solubility. Thaum lub stirring reactor tau siv los ua cov khoom siv tshuaj tiv thaiv, qhov permeability ntawm chloroethyl cawv etherification tus neeg sawv cev tau zoo dua ntawm 68 ℃ rau 4h. Thaum cov molar piv ntawm chloroethanol rau cellulose monosaccharide yog 3: 1, qhov tshwm sim HEC muaj cov dej solubility zoo dua, thiab cov tshuaj tiv thaiv etherification tau nce mus rau 66%.

Cov tshuaj tiv thaiv kev ua haujlwm thiab cov tshuaj tiv thaiv ceev ntawm etherizing tus neeg sawv cev chloroacetic acid yog ntau dua li ntawm chloroethanol, thiab lub tshuab ua kom lub zog ua kom cov khoom siv tshuaj tiv thaiv etherizing muaj qhov zoo ntawm cov kneader, uas zoo heev txhim kho cov tshuaj tiv thaiv etherizing. Lub siab transmittivity ntawm CMC kuj indirectly qhia hais tias lub stirring reactor li etherizing cov tshuaj tiv thaiv cov khoom yuav txhim kho lub homogeneity ntawm etherizing cov tshuaj tiv thaiv. Qhov no yog vim hais tias cov saw cellulose muaj peb pawg hydroxyl ntawm txhua lub suab paj nruag-paj pawg, thiab tsuas yog nyob rau hauv ib lub xeev o los yog yaj yog tag nrho cov cellulose hydroxyl khub ntawm etherifying agent molecules nkag tau. Cov tshuaj tiv thaiv etherification ntawm cellulose feem ntau yog cov tshuaj tiv thaiv heterogeneous los ntawm sab nraud mus rau sab hauv, tshwj xeeb tshaj yog nyob rau hauv thaj tsam crystalline ntawm cellulose. Thaum cov qauv siv lead ua ntawm cellulose tseem nyob tsis muaj qhov cuam tshuam ntawm sab nraud quab yuam, tus neeg sawv cev etherifying nyuaj rau nkag mus rau cov qauv crystalline, cuam tshuam rau homogeneity ntawm cov tshuaj tiv thaiv heterogeneous. Yog li ntawd, los ntawm pretreating lub refined paj rwb (xws li nce qhov tshwj xeeb nto ntawm refined paj rwb), reactivity ntawm refined paj rwb tuaj yeem txhim kho. Nyob rau hauv lub loj da dej piv (ethanol / cellulose los yog isopropyl cawv / cellulose thiab high-speed stirring cov tshuaj tiv thaiv, raws li lub laj thawj, qhov kev txiav txim ntawm cellulose crystallization cheeb tsam yuav raug txo, lub sij hawm no lub cellulose muaj zog o, kom o. ntawm thaj tsam amorphous thiab crystalline cellulose nyhav zoo ib yam, Yog li, lub reactivity ntawm amorphous cheeb tsam thiab crystalline cheeb tsam yog zoo sib xws.

Los ntawm txoj kev tsom xam ntawm infrared spectrum thiab X-ray diffraction tsom xam, cov txheej txheem etherification cov tshuaj tiv thaiv ntawm cellulose tuaj yeem nkag siab ntau dua thaum nplawm reactor siv los ua cov khoom siv tshuaj tiv thaiv etherification.

Ntawm no, infrared spectra thiab X-ray diffraction spectra tau soj ntsuam. Cov etherification cov tshuaj tiv thaiv ntawm CMC thiab HEC tau ua nyob rau hauv ib tug stirred reactor nyob rau hauv cov tshuaj tiv thaiv tej yam kev mob tau piav saum toj no.

Kev tsom xam infrared spectrum qhia tau hais tias etheration cov tshuaj tiv thaiv ntawm CMC thiab HEC hloov tsis tu ncua nrog rau ncua sij hawm cov tshuaj tiv thaiv, qib ntawm kev hloov pauv txawv.

Los ntawm kev tsom xam ntawm X-ray diffraction qauv, lub crystallinity ntawm CMC thiab HEC nyhav rau xoom nrog rau ncua sij hawm cov tshuaj tiv thaiv, qhia tau hais tias cov txheej txheem decrystallisation tau pib paub nyob rau hauv alkalization theem thiab cua sov theem ua ntej etherification cov tshuaj tiv thaiv ntawm refined paj rwb. . Yog li ntawd, carboxymethyl thiab hydroxyethyl etherification reactivity ntawm refined paj rwb tsis yog tsuas yog txwv los ntawm crystallinity ntawm refined paj rwb. Nws muaj feem xyuam rau permeability ntawm etherifying tus neeg sawv cev. Nws tuaj yeem pom tau tias cov tshuaj tiv thaiv etherification ntawm CMC thiab HEC yog nqa tawm nrog nplawm reactor ua cov khoom siv tshuaj tiv thaiv. Nyob rau hauv kev kub ceev nplawm, nws muaj txiaj ntsig zoo rau cov txheej txheem decrystallization ntawm cov paj rwb refined nyob rau hauv alkalization theem thiab cua sov theem ua ntej etherification cov tshuaj tiv thaiv, thiab pab tus neeg sawv cev etherification permeate rau hauv cellulose, thiaj li los txhim kho cov etherification cov tshuaj tiv thaiv efficiency thiab hloov uniformity. .

Hauv kev xaus, qhov kev tshawb fawb no qhia txog qhov cuam tshuam ntawm kev sib zog ua kom muaj zog thiab lwm yam ntawm cov tshuaj tiv thaiv kev ua haujlwm ntawm cov txheej txheem tshuaj tiv thaiv. Yog li ntawd, lub tswv yim ntawm txoj kev tshawb no yog raws li nram no: nyob rau hauv lub heterogeneous etheration cov tshuaj tiv thaiv kab mob, kev siv ntawm loj da dej piv thiab siab stirring siv, thiab lwm yam., yog lub hauv paus tej yam kev mob rau kev npaj ntawm kwv yees li homogeneous cellulose ether nrog substituent pab pawg neeg. kev faib tawm; Nyob rau hauv ib qho tshwj xeeb heterogeneous etheration cov tshuaj tiv thaiv, kev ua haujlwm siab ntawm cellulose ether nrog kwv yees li kev faib tawm ntawm cov khoom hloov pauv tuaj yeem npaj tau los ntawm kev siv lub tshuab ua kom muaj zog ua cov khoom siv tshuaj tiv thaiv, uas qhia tau hais tias cellulose ether aqueous tov muaj qhov xa tawm siab, uas yog qhov tseem ceeb heev los nthuav cov khoom. thiab kev ua haujlwm ntawm cellulose ether. Lub tshuab kneading yog siv los ua cov khoom siv tshuaj tiv thaiv los kawm etherification cov tshuaj tiv thaiv ntawm cov paj rwb refined. Vim yog qhov qis qis, nws tsis zoo rau kev nkag mus ntawm tus neeg sawv cev etherification, thiab muaj qee qhov tsis zoo xws li kev faib ua feem ntau ntawm sab thiab tsis zoo faib tsis zoo ntawm etherification substituents.