Etherification dauki a kan cellulose ether

The etherification aiki na cellulose aka yi nazari da kneading inji da stirring bi da bi, da hydroxyethyl cellulose da carboxymethyl cellulose aka shirya da chloroethanol da monochloroacetic acid bi da bi. Sakamakon ya nuna cewa etherification dauki na cellulose da aka za'ayi ta hanyar zuga reactor karkashin yanayin babban tsanani tashin hankali. Cellulose yana da mai kyau etherification reactivity, wanda shi ne mafi alhẽri daga kneader hanya a inganta etherification yadda ya dace da kuma inganta haske watsa samfurin a cikin ruwa bayani. samfurori.

Mabuɗin kalmomi:amsawar etherification; Cellulose;Hydroxyethyl cellulose; Carboxymethyl cellulose

A cikin haɓaka samfuran ether cellulose na auduga mai ladabi, ana amfani da hanyar ƙarfi sosai kuma ana amfani da injin ƙwanƙwasa azaman kayan aiki. Duk da haka, cellulose auduga ya ƙunshi yankuna na crystal inda aka tsara kwayoyin halitta da kyau kuma a hankali. Lokacin da aka yi amfani da na'ura mai ƙwanƙwasa azaman kayan aiki na kayan aiki, ƙuƙwalwar hannu na na'ura yana jinkirin lokacin amsawa, kuma juriya na etherifying wakili don shigar da nau'i daban-daban na cellulose yana da girma kuma gudun yana jinkirin, yana haifar da lokaci mai tsawo, babban rabo na gefe. halayen da rashin daidaituwa na rarraba ƙungiyoyi masu maye a kan sarƙoƙi na kwayoyin cellulose.

Yawancin lokaci halayen etherification na cellulose shine nau'i mai ban sha'awa a waje da ciki. Idan babu wani aiki mai ƙarfi na waje, wakili na etherifying yana da wuya a shigar da yankin crystallization na cellulose. Kuma ta hanyar pretreatment na mai ladabi auduga (kamar yin amfani da jiki hanyoyin da za a kara surface na mai ladabi auduga), a lokaci guda tare da stirring reactor ga dauki kayan aiki, ta yin amfani da m stirring etherification dauki, bisa ga tunani, cellulose iya karfi kumburi, da kumburi. na cellulose amorphous yankin da crystallization yankin o ƙarin tabbatar da zama m, inganta dauki aiki. Rarraba iri ɗaya na masu maye gurbin ether cellulose a cikin tsarin amsawar etherogeneous etherification ana iya samun ta ta hanyar ƙara ƙarfin motsa jiki na waje. Don haka zai zama makomar ci gaban ƙasarmu don haɓaka samfuran etherification na cellulose mai inganci tare da nau'in abin da aka zuga a matsayin kayan aiki.

1. Bangaren gwaji

1.1 Abubuwan da aka ƙera auduga cellulose don gwaji

Dangane da nau'ikan kayan aiki daban-daban da aka yi amfani da su a cikin gwajin, hanyoyin pretreatment na cellulose auduga sun bambanta. Lokacin da aka yi amfani da kneader a matsayin kayan aikin amsawa, hanyoyin da aka riga aka tsara su ma sun bambanta. Lokacin da aka yi amfani da kneader a matsayin kayan aiki na amsawa, crystallinity na cellulose auduga mai ladabi da aka yi amfani da shi shine 43.9%, kuma matsakaicin tsayin cellulose mai ladabi shine 15 ~ 20mm. The crystallinity na mai ladabi auduga cellulose ne 32.3% da matsakaicin tsawon mai ladabi auduga cellulose ne kasa da 1mm lokacin da stirring reactor da ake amfani da matsayin dauki kayan aiki.

1.2 Ci gaban carboxymethyl cellulose da hydroxyethyl cellulose

A shirye-shiryen na carboxymethyl cellulose da hydroxyethyl cellulose za a iya za'ayi ta amfani da 2L kneader matsayin dauki kayan aiki (matsakaicin gudun a lokacin dauki ne 50r / min) da kuma 2L stirring reactor a matsayin dauki kayan aiki (matsakaicin gudun a lokacin dauki ne 500r / min).

A lokacin amsawa, duk albarkatun ƙasa an samo su ne daga tsananin ƙididdiga. Ana wanke samfurin da aka samo daga abin da aka yi da shi tare da w = 95% ethanol, sa'an nan kuma ya bushe ta hanyar motsa jiki don 24h a ƙarƙashin mummunan matsa lamba na 60 ℃ da 0.005mpa. Danshi abun ciki na samfurin da aka samu shine w = 2.7% ± 0.3%, kuma ana wanke samfurin samfurin don bincike har sai abun cikin ash w <0.2%.

Matakan shirye-shirye na na'ura mai murɗa kamar kayan aiki sune kamar haka:

Etherification dauki → samfurin wankewa → bushewa → grated granulation → marufi da za'ayi a cikin kneader.

The shiri matakai na stirring reactor a matsayin dauki kayan aiki ne kamar haka:

Etherification dauki → samfurin wanke → bushewa da granulation → marufi ne da za'ayi a cikin wani zuga reactor.

Ana iya ganin cewa ana amfani da kneader a matsayin kayan aiki na kayan aiki don shirye-shiryen halayen ƙananan tasiri, bushewa da granulation granulation mataki-mataki, kuma ingancin samfurin zai ragu sosai a cikin tsarin nika.

Halaye na shirye-shiryen tsari tare da zuga reactor kamar yadda dauki kayan aiki ne kamar haka: high dauki yadda ya dace, da samfurin granulation ba ya dauko gargajiya granulation tsari Hanyar bushewa da nika, da bushewa da granulation tsari ne da za'ayi a lokaci guda tare da. samfuran da ba a bushe ba bayan wankewa, kuma ingancin samfurin ya kasance baya canzawa a cikin bushewa da tsarin granulation.

1.3 Binciken diffraction X-ray

Rigaku D/max-3A X-ray diffractometer, graphite monochromator, Θ Angle ya kasance 8 ° ~ 30 °, CuKα ray, matsa lamba tube da tube tube sun kasance 30kV da 30mA.

1.4 Binciken bakan infrared

An yi amfani da Spectrum-2000PE FTIR infrared spectrometer don nazarin bakan infrared. Duk samfuran don nazarin bakan infrared suna da nauyin 0.0020g. An haɗu da waɗannan samfurori tare da 0.1600g KBr, bi da bi, sa'an nan kuma danna (tare da kauri na <0.8mm) kuma an bincika.

1.5 Gano watsawa

An gano watsawa ta 721 spectrophotometer. Maganin CMC w=w1% an saka shi a cikin tasa mai launi 1cm a tsawon 590nm.

1.6 Digiri na gano maye gurbin

An auna matakin maye gurbin HEC na hydroxyethyl cellulose ta daidaitaccen hanyar nazarin sinadarai. Ka'idar ita ce HEC na iya bazuwa ta hanyar HI hydroiodate a 123 ℃, kuma ana iya sanin matakin maye gurbin HEC ta hanyar auna abubuwan da suka lalace da ethylene da ethylene iodide da aka samar. Hakanan ana iya gwada matakin maye gurbin hydroxymethyl cellulose ta daidaitattun hanyoyin nazarin sinadarai.

2. Sakamako da tattaunawa

Ana amfani da nau'i biyu na sintiri guda biyu anan: ɗayan yana durƙusar da kayan aikin da aka yi, a cikin kayan aikin da ake yiwa giya, ERTherware na Siyarwa na Carrafa Cellulose an yi nazari. Daga cikin su, halayen fasaha na injin cukuwa kamar kayan aikin amsawa sune: A cikin amsawa, saurin murƙushe hannu yana jinkirin, lokacin amsawa yana da tsayi, adadin halayen gefe yana da yawa, ƙimar amfani da etherifying wakili yana da ƙasa, kuma uniformity na maye gurbin rarraba rukuni a cikin amsawar etherizing ba shi da kyau. Tsarin bincike na iya iyakance shi kawai ga ɗan ƙaramin yanayin amsawa. Bugu da kari, da daidaitawa da controllability na babban dauki yanayi (kamar wanka rabo, alkali maida hankali, kneading hannu ta gudun kneading inji) ne sosai matalauta. Yana da wuya a cimma daidaitattun daidaituwar halayen etherification da kuma nazarin yawan canja wurin taro da shigar da tsarin amsawar etherification cikin zurfi. The tsari fasali na stirring reactor kamar yadda dauki kayan aiki ne: azumi stirring gudun a dauki, sauri dauki gudun, high amfani kudi na etherizing wakili, uniform rarraba etherizing substituents, daidaitacce da kuma controllable babban dauki yanayi.

Carboxymethyl cellulose CMC aka shirya ta kneader dauki kayan aiki da stirring reactor dauki kayan aiki bi da bi. Lokacin da aka yi amfani da kneader azaman kayan aikin amsawa, ƙarfin motsawa ya ragu kuma matsakaicin saurin juyawa shine 50r / min. Lokacin da aka yi amfani da reactor mai motsawa azaman kayan aiki, ƙarfin motsawa ya kasance babba kuma matsakaicin juyawa shine 500r / min. Lokacin da rabon molar monochloroacetic acid zuwa cellulose monosaccharide ya kasance 1:5:1, lokacin amsawa shine 1.5h a 68 ℃. Hasken wutar lantarki na CMC da aka samu ta injin kneading shine 98.02% kuma ingantaccen etherification shine 72% saboda kyakkyawan haɓakar CM a cikin wakili na chloroacetic acid. Lokacin da aka yi amfani da reactor mai tayar da hankali azaman kayan aikin amsawa, haɓakar etherifying wakili ya fi kyau, watsawar CMC ya kasance 99.56%, kuma an haɓaka ƙimar haɓakar etherizing zuwa 81%.

Hydroxyethyl cellulose HEC aka shirya tare da kneader da stirring reactor a matsayin dauki kayan aiki. Lokacin da aka yi amfani da kneader azaman kayan aiki na amsawa, ƙimar amsawar wakili na etherizing shine 47% kuma mai narkewar ruwa ba shi da kyau lokacin da ƙarancin maganin chloroethyl barasa ya kasance matalauta kuma ƙimar molar chloroethanol zuwa cellulose monosaccharide shine 3: 1 a 60 ℃ na 4h. . Sai kawai lokacin da rabon molar na chloroethanol zuwa cellulose monosaccharides shine 6: 1, ana iya samar da samfuran da ke da ruwa mai kyau. Lokacin da aka yi amfani da reactor mai motsawa azaman kayan aiki, haɓakar chloroethyl barasa etherification wakili ya zama mafi kyau a 68 ℃ na 4h. Lokacin da molar rabo na chloroethanol zuwa cellulose monosaccharide ya kasance 3: 1, sakamakon HEC yana da mafi kyau solubility na ruwa, da kuma etherification dauki yadda ya dace ya karu zuwa 66%.

A dauki yadda ya dace da dauki gudun da etherizing wakili chloroacetic acid ne da yawa mafi girma fiye da na chloroethanol, da kuma stirring reactor kamar yadda etherizing dauki kayan aiki yana da fili abũbuwan amfãni a kan kneader, wanda ƙwarai inganta etherizing dauki yadda ya dace. A high transmittivity na CMC kuma a kaikaice nuna cewa stirring reactor kamar yadda etherizing dauki kayan aiki iya inganta homogeneity na etherizing dauki. Wannan saboda sarkar cellulose tana da ƙungiyoyin hydroxyl guda uku akan kowace zoben rukuni-rukuni na glucose, kuma kawai a cikin kumbura mai ƙarfi ko narkar da duk nau'ikan nau'ikan kwayoyin halitta na cellulose hydroxyl suna iya samun dama ga. A etherification dauki na cellulose yawanci wani iri-iri dauki daga waje zuwa ciki, musamman a cikin crystalline yankin cellulose. Lokacin da tsarin crystal na cellulose ya ci gaba da kasancewa ba tare da tasirin tasirin waje ba, wakili na etherifying yana da wuya a shigar da tsarin crystalline, yana rinjayar kamannin halayen halayen. Sabili da haka, ta hanyar yin gyaran auduga mai ladabi (kamar ƙara takamaiman saman auduga mai ladabi), za'a iya inganta aikin auduga mai ladabi. A cikin babban wanka rabo (ethanol / cellulose ko isopropyl barasa / cellulose da high-gudun stirring dauki, bisa ga dalili, da tsari na cellulose crystallization zone za a rage, a wannan lokacin da cellulose iya karfi kumbura, sabõda haka, kumburi. na amorphous da crystalline cellulose zone oyan zama m, Saboda haka, reactivity na amorphous yankin da crystalline yankin ne kama.

Ta hanyar infrared bakan bincike da X-ray diffraction bincike, da etherification dauki tsari na cellulose za a iya fahimta more a sarari lokacin da zuga reactor da ake amfani da etherification dauki kayan aiki.

Anan, an yi nazarin spectra na infrared da kuma raƙuman raɗaɗi na X-ray. The etherification dauki na CMC da HEC da aka za'ayi a cikin wani zuga reactor karkashin dauki yanayin da aka bayyana a sama.

Binciken bakan infrared ya nuna cewa tasirin etheration na CMC da HEC yana canzawa akai-akai tare da tsawaita lokacin amsawa, matakin maye gurbin ya bambanta.

Ta hanyar bincike na X-ray diffraction juna, da crystallinity na CMC da HEC o ƙarin tabbatar da sifili tare da tsawo na dauki lokaci, yana nuna cewa decrystallisation tsari da aka m an gane a cikin alkalization mataki da kuma dumama mataki kafin etherification dauki na mai ladabi auduga. . Saboda haka, karboxymethyl da hydroxyethyl etherification reactivity na auduga mai ladabi ba a iyakance shi ta hanyar crystallinity na auduga mai ladabi ba. Yana da alaƙa da haɓakar etherifying wakili. Ana iya nuna cewa ana aiwatar da halayen etherification na CMC da HEC tare da reactor mai motsawa azaman kayan aiki. A karkashin high gudun stirring, yana da amfani ga decrystallization aiwatar da mai ladabi auduga a cikin alkalization mataki da kuma dumama mataki kafin etherification dauki, da kuma taimaka etherification wakili zuwa permeate cikin cellulose, don inganta etherification dauki yadda ya dace da kuma maye gurbin uniformity. .

A ƙarshe, wannan binciken yana jaddada tasirin ƙarfin motsa jiki da sauran abubuwan da ke tattare da halayen halayen yayin aiwatar da amsawa. Saboda haka, da shawara na wannan binciken dogara ne a kan wadannan dalilai: A cikin heterogeneous etheration dauki tsarin, da yin amfani da babban wanka rabo da kuma high stirring tsanani, da dai sauransu, shi ne ainihin yanayi na shirye-shiryen kamar kama cellulose ether tare da substituent kungiyar. rarraba; A cikin wani takamaiman tsarin amsawar etherogeneous, babban aikin cellulose ether tare da kusan rarraba abubuwan maye za a iya shirya ta hanyar amfani da reactor mai motsawa azaman kayan aiki, wanda ke nuna cewa maganin ruwa na cellulose ether yana da babban watsawa, wanda ke da mahimmanci don faɗaɗa Properties. da kuma ayyuka na cellulose ether. Ana amfani da na'ura mai dunƙulewa azaman kayan aiki don nazarin halayen etherification na auduga mai ladabi. Saboda da low stirring tsanani, ba shi da kyau ga shigar azzakari cikin farji na etherification wakili, kuma yana da wasu disadvantages kamar high rabo daga gefen halayen da matalauta rarraba uniformity na etherification substituents.