Etherification reaction pa cellulose ether

Ntchito ya etherification ya cellulose idaphunziridwa ndi makina okanda ndi oyambitsa riyakitala motsatana, ndipo hydroxyethyl cellulose ndi carboxymethyl cellulose zidakonzedwa ndi chloroethanol ndi monochloroacetic acid motsatana. Zotsatira zake zinawonetsa kuti etherification ya cellulose idachitika ndi kuyambitsa riyakitala pansi pamavuto akulu kwambiri. Cellulose ali wabwino etherification reactivity, amene ali bwino kuposa kneader njira kuwongolera etherification Mwachangu ndi utithandize kuwala kufala kwa mankhwala mu njira amadzimadzi. mankhwala.

Mawu ofunikira:etherification reaction; Ma cellulose;Hydroxyethyl cellulose; Carboxymethyl cellulose

Popanga zinthu zopangidwa ndi thonje la cellulose ether, njira yosungunulira imagwiritsidwa ntchito kwambiri ndipo makina okanda amagwiritsidwa ntchito ngati zida zochitira. Komabe, cellulose ya thonje imapangidwa makamaka ndi zigawo za kristalo komwe mamolekyu amasanjidwa bwino komanso moyandikira. Pamene kukankha makina ntchito monga zida anachita, ndi kukankha mkono wa makina kukankha ndi pang'onopang'ono pa anachita, ndi kukana etherifying wothandizila kulowa zigawo zosiyanasiyana za mapadi lalikulu ndi liwiro ndi wodekha, chifukwa mu nthawi yaitali anachita, mkulu gawo la mbali. machitidwe ndi kugawa kosagwirizana kwa magulu olowa m'malo pa cellulose ma cell chain.

Nthawi zambiri etherification zimachitikira mapadi ndi heterogeneous anachita kunja ndi mkati. Ngati palibe kunja zazikulu kanthu, etherifying wothandizira n'zovuta kulowa crystallization zone wa mapadi. Ndipo mwa pretreatment wa thonje woyengedwa (monga kugwiritsa ntchito njira thupi kuonjezera pamwamba thonje woyengedwa), pa nthawi yomweyo ndi yogwira riyakitala kwa anachita zida, ntchito mofulumira yogwira mtima etherification anachita, malinga ndi kulingalira, mapadi akhoza kwambiri kutupa, ndi kutupa. wa mapadi amorphous dera ndi crystallization dera amakonda kukhala mogwirizana, kusintha anachita ntchito. The homogeneous kugawa kwa cellulose etha m'malo mu heterogeneous etherification kachitidwe kachitidwe kakhoza kutheka powonjezera mphamvu yakunja yogwira ntchito. Chifukwa chake chikhala tsogolo lachitukuko cha dziko lathu kupanga zinthu zapamwamba kwambiri za cellulose etherification zokhala ndi ketulo yamtundu wowumbidwa ngati zida zochitira.

1. Gawo loyesera

1.1 Woyengedwa thonje cellulose yaiwisi kuti ayesedwe

Malinga ndi zida zosiyanasiyana zomwe zimagwiritsidwa ntchito poyesera, njira zopangira mankhwala a thonje cellulose ndizosiyana. Pamene kneader imagwiritsidwa ntchito ngati zida zochitira, njira zopangira mankhwala zimasiyananso. Pamene kneader imagwiritsidwa ntchito ngati zida zomwe zimapangidwira, crystallinity ya cellulose yoyengedwa ya thonje yomwe imagwiritsidwa ntchito ndi 43.9%, ndipo kutalika kwa thonje woyengedwa ndi 15 ~ 20mm. The crystallinity wa woyengedwa thonje mapadi ndi 32.3% ndi pafupifupi kutalika woyengedwa thonje mapadi ndi zosakwana 1mm pamene oyambitsa riyakitala ntchito ngati zida anachita.

1.2 Kukula kwa carboxymethyl cellulose ndi hydroxyethyl cellulose

Kukonzekera kwa carboxymethyl mapadi ndi hydroxyethyl mapadi angathe kuchitidwa pogwiritsa ntchito 2L kneader monga zida anachita (avareji liwiro pa anachita ndi 50r/mphindi) ndi 2L yogwira riyakitala monga anachita zida (avareji liwiro pa anachita ndi 500r/mphindi).

Pa anachita, zonse zopangira anachokera ku okhwima kachulukidwe anachita. The mankhwala analandira kuchokera anachita osambitsidwa ndi w = 95% Mowa, ndiyeno zouma ndi zingalowe kwa 24h pansi pa mavuto oipa 60 ℃ ndi 0.005mpa. Chinyezi chachitsanzo chomwe chinapezedwa ndi w = 2.7% ± 0.3%, ndipo chitsanzo cha mankhwala kuti chiwunikidwe chimatsukidwa mpaka phulusa likhale ndi <0.2%.

Masitepe okonzekera makina okanda ngati zida zochitira ndi awa:

Etherification reaction → kutsuka kwazinthu → kuyanika → granulation granulation → kuyika kumachitika mu kneader.

Kukonzekera masitepe oyambitsa riyakitala ngati zida zochitira ndi motere:

Etherification reaction → kutsuka kwazinthu → kuyanika ndi granulation → kuyika kumachitika mu riyakitala yogwedezeka.

Tingaone kuti kneader ntchito monga zida anachita pokonzekera makhalidwe a otsika anachita dzuwa, kuyanika ndi akupera granulation sitepe ndi sitepe, ndi khalidwe la mankhwala adzakhala kwambiri yafupika ndondomeko akupera.

Makhalidwe a ndondomeko kukonzekera ndi analimbikitsa riyakitala monga zida anachita ndi motere: mkulu anachita dzuwa, mankhwala granulation satengera chikhalidwe granulation ndondomeko njira kuyanika ndi akupera, ndi kuyanika ndi granulation ndondomeko ikuchitika nthawi yomweyo ndi zinthu zosaumitsidwa pambuyo kutsuka, ndipo khalidwe la mankhwala silinasinthe mu kuyanika ndi granulation ndondomeko.

1.3 Kusanthula kwa X-ray diffraction

Kusanthula kwa X-ray kunachitika ndi Rigaku D / max-3A X-ray diffractometer, graphite monochromator, Θ Angle inali 8 ° ~ 30 °, CuKα ray, kuthamanga kwa chubu ndi kutuluka kwa chubu kunali 30kV ndi 30mA.

1.4 Kusanthula kwa ma infrared spectrum

Spectrum-2000PE FTIR infrared spectrometer idagwiritsidwa ntchito posanthula mawonedwe a infuraredi. Zitsanzo zonse zowunikira ma infrared spectrum zinali zolemera 0.0020g. Zitsanzozi zidasakanizidwa ndi 0.1600g KBr, motsatana, ndikukanikizidwa (ndi makulidwe a <0.8mm) ndikuwunikidwa.

1.5 Kuzindikira ma transmittance

Kutumizako kudazindikirika ndi 721 spectrophotometer. Yankho la CMC w = w1% linayikidwa mu mbale ya 1cm colorimetric pa 590nm wavelength.

1.6 Digiri ya kuzindikira kolowa m'malo

The HEC substitution degree ya hydroxyethyl cellulose inayesedwa ndi njira yowunikira mankhwala. Mfundoyi ndi yakuti HEC ikhoza kuwola ndi HI hydroiodate pa 123 ℃, ndipo mlingo wa kulowetsedwa kwa HEC ukhoza kudziwika poyesa zinthu zowonongeka ethylene ndi ethylene iodide zopangidwa. Mlingo wolowa m'malo mwa hydroxymethyl cellulose ungathenso kuyesedwa ndi njira zowunikira zamankhwala.

2. Zotsatira ndi zokambirana

Pali mitundu iwiri ya ketulo yomwe imagwiritsidwa ntchito pano: imodzi ndi makina opondera monga zida zochitira, ina ikuyambitsa ketulo yamtundu monga momwe zimachitikira, muzinthu zowonongeka, zamchere zamchere ndi madzi akumwa zosungunulira, etherification anachita ya thonje yoyengedwa ya thonje imaphunziridwa. Zina mwazo, zida zamakono zamakina opondera monga zida zochitira ndi: Pochita, liwiro la mkono wokankhira limakhala pang'onopang'ono, nthawi yochitira ndi yayitali, gawo la machitidwe am'mbali ndi lalitali, kuchuluka kwa magwiritsidwe a etherifying agent ndi otsika, ndipo Kufanana kwa kugawa kwamagulu m'malo mwa etherizing ndikovuta. Kafufuzidwe kachitidwe kakhoza kungokhala pazochitika zochepa chabe. Komanso, kusintha ndi controllability wa zinthu zikuluzikulu anachita (monga kusamba chiŵerengero, ndende alkali, kukanda mkono liwiro la kukankha makina) ndi osauka kwambiri. N'zovuta kukwaniritsa pafupifupi kufanana kwa etherification anachita ndi kuphunzira misa kutengerapo ndi malowedwe a etherification anachita ndondomeko mozama. The ndondomeko mbali ya oyambitsa riyakitala monga zida anachita ndi: kudya yogwira mtima liwiro anachita, kudya anachita liwiro, mkulu magwiritsidwe mlingo wa wothandizila etherizing, yunifolomu kugawa m'malo etherizing, chosinthika ndi controllable zinthu zazikulu anachita.

Carboxymethyl cellulose CMC idakonzedwa ndi zida za kneader reaction ndi zida zoyambitsa riyakitala motsatana. Pamene kneader idagwiritsidwa ntchito ngati zida zomwe zimachitikira, mphamvu yolimbikitsa inali yochepa ndipo pafupifupi liwiro lozungulira linali 50r / min. Pamene oyambitsa riyakitala ankagwiritsidwa ntchito monga zida anachita, ndi yogwira mtima mwamphamvu anali mkulu ndipo pafupifupi kasinthasintha liwiro anali 500r/mphindi. Pamene chiŵerengero cha molar cha monochloroacetic acid ku cellulose monosaccharide chinali 1: 5: 1, nthawi yochitapo inali 1.5h pa 68 ℃. Kuwala kwa CMC komwe kudapezedwa ndi makina okanda kunali 98.02% ndipo mphamvu ya etherification inali 72% chifukwa cha kukwanira kwabwino kwa CM mu chloroacetic acid etherifying agent. Pamene oyambitsa riyakitala ntchito monga zida anachita, ndi permeability wa etherifying wothandizila anali bwino, ndi transmittance CMC anali 99,56%, ndi etherizing anachita dzuwa chinawonjezeka kwa 81%.

Hydroxyethyl mapadi HEC anakonzedwa ndi kneader ndi yogwira riyakitala monga anachita zida. Pamene kneader imagwiritsidwa ntchito ngati zida zochitira, mphamvu ya etherizing agent inali 47% ndipo kusungunuka kwamadzi kunali kocheperako pamene chloroethyl mowa etherizing wothandizila unali wochepa ndipo chiŵerengero cha molar cha chloroethanol ndi cellulose monosaccharide chinali 3: 1 pa 60 ℃ kwa 4h. . Pokhapokha pamene chiŵerengero cha molar cha chloroethanol ndi cellulose monosaccharides ndi 6: 1, mankhwala omwe ali ndi madzi abwino amatha kupangidwa. Pamene riyakitala yogwira ntchito idagwiritsidwa ntchito ngati zida zomwe zimapangidwira, mphamvu ya chloroethyl mowa etherification wothandizira idakhala bwino pa 68 ℃ kwa 4h. Pamene chiŵerengero cha molar cha chloroethanol ndi cellulose monosaccharide chinali 3: 1, zotsatira za HEC zinali ndi madzi osungunuka bwino, ndipo mphamvu ya etherification anachita inawonjezeka kufika 66%.

Zimene Mwachangu ndi anachita liwiro la etherizing wothandizira chloroacetic asidi ndi apamwamba kuposa chloroethanol, ndi yogwira riyakitala monga etherizing anachita zida ali ndi ubwino zoonekeratu pa kneader, amene kwambiri bwino etherizing anachita dzuwa. Kupatsirana kwakukulu kwa CMC kumawonetsanso mosapita m'mbali kuti riyakitala yolimbikitsa ngati zida za etherizing zitha kusintha homogeneity ya etherizing reaction. Izi zili choncho chifukwa unyolo wa cellulose uli ndi magulu atatu a hydroxyl pa mphete ya gulu lililonse la shuga, ndipo pakatupa kwambiri kapena kusungunuka m'malo onse a cellulose hydroxyl ma molecule a etherifying agent amatha kupezeka. The etherification zimachitikira mapadi nthawi zambiri heterogeneous zimachitikira kuchokera kunja kupita mkati, makamaka mu crystalline dera mapadi. Pamene kristalo dongosolo mapadi amakhalabe popanda mphamvu ya kunja mphamvu, etherifying wothandizila n'zovuta kulowa crystalline dongosolo, zimakhudza homogeneity wa heterogeneous anachita. Chifukwa chake, pokonzekera thonje loyengedwa bwino (monga kukulitsa malo enieni a thonje loyengedwa), reactivity ya thonje woyengedwa akhoza kusintha. Mu bafa lalikulu chiŵerengero (ethanol / mapadi kapena isopropyl mowa / mapadi ndi mkulu-liwiro yogwira mtima anachita, malinga ndi kulingalira, dongosolo la mapadi crystallization zone adzakhala yafupika, pa nthawi imeneyi mapadi akhoza kwambiri kutupa, kotero kuti kutupa wa amorphous ndi crystalline mapadi zone amakhala kugwirizana, Choncho, reactivity wa dera amorphous ndi crystalline dera ndi ofanana.

Pogwiritsa ntchito infuraredi sipekitiramu kusanthula ndi X-ray diffraction kusanthula, etherification anachita ndondomeko mapadi akhoza kumveka bwino kwambiri pamene yogwira riyakitala ntchito ngati etherification reaction zida.

Apa, ma infrared spectra ndi ma X-ray diffraction spectra adawunikidwa. The etherification anachita wa CMC ndi HEC inachitika mu analimbikitsa riyakitala pansi anachita zinthu tafotokozazi.

The infuraredi sipekitiramu kusanthula limasonyeza kuti etheration anachita CMC ndi HEC kusintha pafupipafupi ndi kukulitsa kachitidwe nthawi, mlingo wa m'malo ndi osiyana.

Kupyolera mu kuwunika kwa X-ray diffraction chitsanzo, crystallinity wa CMC ndi HEC amakonda ziro ndi kutambasuka kwa nthawi anachita, kusonyeza kuti decrystallization ndondomeko wakhala anazindikira mu siteji alkalization ndi kutentha siteji pamaso etherification anachita wa thonje woyengedwa. . Chifukwa chake, carboxymethyl ndi hydroxyethyl etherification reactivity ya thonje woyengedwa sikulinso makamaka ndi crystallinity wa thonje woyengedwa. Zimagwirizana ndi permeability wa etherifying wothandizira. Zingasonyezedwe kuti etherification anachita CMC ndi HEC ikuchitika ndi oyambitsa riyakitala monga zida anachita. Pansi mkulu liwiro yogwira mtima, ndi opindulitsa kwa decrystallization ndondomeko ya thonje woyengedwa mu alkalization siteji ndi Kutentha siteji pamaso etherification anachita, ndipo amathandiza wothandizila etherification kuti zilowerere mu mapadi, kuti patsogolo etherification anachita dzuwa ndi m'malo yunifolomu. .

Pomaliza, phunziroli akutsindika chikoka cha oyambitsa mphamvu ndi zinthu zina pa anachita dzuwa pa anachita ndondomeko. Choncho, maganizo a phunziroli zachokera pazifukwa zotsatirazi: Mu heterogeneous etheration anachita dongosolo, ntchito lalikulu kusamba chiŵerengero ndi mkulu yogwira mtima kwambiri, etc., ndi mfundo zofunika kukonzekera pafupifupi homogeneous mapadi efa ndi substituent gulu. kugawa; Mu yeniyeni heterogeneous etheration anachita dongosolo, mkulu ntchito mapadi etere ndi pafupifupi yunifolomu kugawa m'malo akhoza kukonzekera pogwiritsa ntchito riyakitala yogwira ntchito monga zida anachita, zomwe zimasonyeza kuti mapadi etero amadzimadzi njira ali transmittance mkulu, amene ali ndi tanthauzo lalikulu kukulitsa katundu. ndi ntchito za cellulose ether. Makina okanda amagwiritsidwa ntchito ngati zida zochitira kuphunzira etherification reaction ya thonje woyengedwa. Chifukwa otsika yogwira mtima kwambiri, si bwino malowedwe a etherification wothandizila, ndipo ali ndi kuipa zina monga mkulu kuchuluka kwa mbali zimachitikira ndi osauka kugawa kufanana kwa etherification substituents.