Ukusabela kwe-Etherification kwi-ether ye-cellulose

Umsebenzi we-etherification we-cellulose waphononongwa ngomatshini wokuxova kunye ne-reactor evuselelayo ngokulandelelana, kunye ne-hydroxyethyl cellulose kunye ne-carboxymethyl cellulose zalungiswa yi-chloroethanol kunye ne-monochloroacetic acid ngokulandelelana. Iziphumo zibonise ukuba i-etherification reaction ye-cellulose yenziwa ngokuvuselela i-reactor phantsi kwemeko yokuphazamiseka okuphezulu. I-Cellulose ine-reactivity ye-etherification elungileyo, engcono kunendlela yokuxova ekuphuculeni ukusebenza kakuhle kwe-etherification kunye nokwandisa ukuhanjiswa kokukhanya kwemveliso kwisisombululo esimanzi.) iimveliso.

Amagama angundoqo:ukusabela kwe-etherification; iSelulosi;Iselulosi yeHydroxyethyl; Carboxymethyl cellulose

Kuphuhliso lwemveliso ye-cotton cellulose ether esulungekileyo, indlela ye-solvent isetyenziswa kakhulu kwaye umatshini wokuxova usetyenziswa njengezixhobo zokuphendula. Nangona kunjalo, i-cotton cellulose iqulunqwe kakhulu yimimandla yekristale apho iimolekyuli zicwangciswe kakuhle kwaye ngokusondeleyo. Xa umatshini wokuxova usetyenziswa njengesixhobo sokuphendula, ingalo yokuxova yomatshini wokuxova iyacotha ngexesha lokusabela, kwaye ukuchasana kwe-etherifying agent ukungena kwiileya ezahlukeneyo zeselulosi kukhulu kwaye isantya sicotha, okukhokelela kwixesha elide lokuphendula, umlinganiselo ophezulu wecala. ukusabela kunye nokusasazwa okungalinganiyo kwamaqela abambeleyo kumatyathanga emolekyuli eselulosi.

Ngokuqhelekileyo i-etherification reaction ye-cellulose yi-heterogeneous reaction ngaphandle nangaphakathi. Ukuba akukho ntshukumo yangaphandle eguquguqukayo, i-etherifying agent inzima ukungena kwindawo ye-crystallization ye-cellulose. Kwaye ngokuphathwa kwangaphambili komqhaphu osulungekisiweyo (njengokusebenzisa iindlela zokwenyama ukunyusa umgangatho womqhaphu osulungekisiweyo), ngaxeshanye kunye ne-reactor evuselelayo yezixhobo zokusabela, usebenzisa ukusabela ngokukhawuleza kwe-etherification, ngokuqiqa, i-cellulose inokudumba kakhulu, ukudumba. indawo ye-cellulose amorphous kunye ne-crystallization area idla ngokuhambelana, ukuphucula umsebenzi wokuphendula. Ukusasazwa okulinganayo kwezixhobo ze-cellulose ether kwi-heterogeneous etherification reaction system inokufezekiswa ngokwandisa amandla angaphandle ashukumisayo. Ke iya kuba ngumkhombandlela wophuhliso lwexesha elizayo welizwe lethu ukuphuhlisa iimveliso ze-cellulose etherification ezikumgangatho ophezulu kunye neketile yokusabela njengesixhobo sokusabela.

1. Inxalenye yovavanyo

1.1 Icotton cellulose ecociweyo imathiriyeli ekrwada yovavanyo

Ngokwezixhobo ezahlukeneyo zokusabela ezisetyenzisiweyo kuvavanyo, iindlela zokunyangwa kwangaphambili zecotton cellulose zahlukile. Xa i-kneader isetyenziswa njengesixhobo sokusabela, iindlela zokunyanga kwangaphambili zikwahluke. Xa i-kneader isetyenziswe njengesixhobo sokuphendula, i-crystallinity ye-cotton cellulose ecocekileyo esetyenzisiweyo yi-43.9%, kunye nobude obuqhelekileyo be-cotton cellulose ecocekileyo yi-15 ~ 20mm. Ubukhazikhazi be-cotton cellulose ecokisiweyo yi-32.3% kwaye ubude obuqhelekileyo be-cotton cellulose esulungekileyo bungaphantsi kwe-1mm xa i-reactor eshukumisayo isetyenziswa njengesixhobo sokusabela.

1.2 Ukuphuhliswa kwe-carboxymethyl cellulose kunye ne-hydroxyethyl cellulose

Ukulungiswa kwe-carboxymethyl cellulose kunye ne-hydroxyethyl cellulose kunokwenziwa ngokusebenzisa i-2L kneader njengesixhobo sokuphendula (isantya esiphakathi ngexesha lokuphendula ngu-50r / min) kunye ne-2L evuselela i-reactor njengesixhobo sokuphendula (isantya esiphakathi ngexesha lokuphendula ngu-500r / min).

Ngethuba lokuphendula, zonke izinto eziluhlaza zithathwe kwi-reaction quantitative engqongqo. Imveliso efunyenwe kwi-reaction ihlanjwe nge-w = 95% ethanol, kwaye yomiswe nge-vacuum ye-24h phantsi koxinzelelo olubi lwe-60 ℃ kunye ne-0.005mpa. Ubumanzi besampulu efunyenweyo ngu-w=2.7%±0.3%, kwaye isampulu yemveliso yokuhlalutya iyahlanjwa de uthuthu lube ngu <0.2%.

Amanyathelo okulungiselela umatshini wokuxova njengezixhobo zokusabela ami ngolu hlobo lulandelayo:

Ukusabela kwe-etherification → ukuhlanjwa kwemveliso → ukomisa → igranulation egraftiweyo → ukupakishwa kuqhutywa kwi- kneader.

Amanyathelo okulungiselela i-reactor eshukumisayo njengesixhobo sokusabela ngala alandelayo:

Ukusabela kwe-etherification → ukuvaswa kwemveliso → ukomiswa kunye negranulation → ukupakishwa kwenziwa kwireactor evuselelweyo.

Ingabonwa ukuba i-kneader isetyenziswa njengezixhobo zokusabela ukulungiselela iimpawu zentsebenzo ephantsi yokusabela, ukomisa kunye nokusila i-granulation inyathelo ngenyathelo, kwaye umgangatho wemveliso uya kuncitshiswa kakhulu kwinkqubo yokusila.

Iimpawu zenkqubo yokulungiselela kunye ne-reactor evuselelweyo njengezixhobo zokusabela zimi ngolu hlobo lulandelayo: ukusebenza kakuhle kokusabela okuphezulu, igranulation yemveliso ayithathi inkqubo yegranulation yemveli yokomisa kunye nokusila, kwaye inkqubo yokomisa kunye negranulation yenziwa ngaxeshanye iimveliso ezingomisiweyo emva kokuhlamba, kwaye umgangatho wemveliso uhlala ungatshintshi kwinkqubo yokumisa kunye ne-granulation.

1.3 Uhlalutyo lwe-X-ray diffraction

Uhlalutyo lwe-X-ray diffraction lwenziwa nguRigaku D / max-3A X-ray diffractometer, i-graphite monochromator, Θ I-Angle yayingu-8 ° ~ 30 °, i-CuKα ray, uxinzelelo lwe-tube kunye ne-tube flow yi-30kV kunye ne-30mA.

1.4 Uhlalutyo lwe-infrared spectrum

I-Spectrum-2000PE FTIR i-infrared spectrometer isetyenziselwe uhlalutyo lwe-infrared spectrum. Zonke iisampuli zohlalutyo lwe-infrared spectrum zazinobunzima be-0.0020g. Ezi sampuli zaxutywa kunye ne-0.1600g KBr, ngokulandelanayo, kwaye emva koko zicinezelwe (ngobunzima be-< 0.8mm) kwaye zihlalutywe.

1.5 Ukubhaqwa kokugqithiselwa

I-transmittance ifunyenwe yi-721 spectrophotometer. Isisombululo se-CMC w=w1% safakwa kwi-1cm ye-colorimetric dish kwi-590nm wavelength.

1.6 Iqondo lokubhaqwa kokutshintshwa

I-HEC substitution degree ye-hydroxyethyl cellulose ilinganiswe ngendlela eqhelekileyo yohlalutyo lweekhemikhali. Umgaqo-siseko kukuba i-HEC inokuboliswa yi-HI hydroiodate kwi-123 ℃, kwaye iqondo lokutshintshwa kwe-HEC likwaziwa ngokulinganisa izinto ezibolileyo i-ethylene kunye ne-ethylene iodide eveliswayo. Umgangatho wokutshintshwa kwe-hydroxymethyl cellulose nawo unokuvavanywa ngeendlela eziqhelekileyo zokuhlalutya iikhemikhali.

2. Iziphumo kunye nengxoxo

Iindidi ezimbini zeketile yokusabela zisetyenziswa apha: enye yeyomatshini wokuxova njengesixhobo sokusabela, enye ivuselela uhlobo lweketile yokusabela njengesixhobo sokusabela, kwinkqubo yokusabela okungafaniyo, imeko yealkaline kunye nenkqubo yokunyibilikisa kwamanzi anxilisayo, ukusabela kwe-etherification yecotton cellulose esulungekileyo iyaphononongwa. Phakathi kwazo, iimpawu zetekhnoloji zomatshini wokuxova njengezixhobo zokuphendula zezi: Ekuphenduleni, isantya sengalo exovayo siyacotha, ixesha lokuphendula lide, umyinge wokuphendulwa kwecala uphezulu, izinga lokusetyenziswa kwe-ejenti etherifying liphantsi, kwaye ukufana kokuhambisa iqela endaweni yokusabela kwe-etherizing kubi. Inkqubo yophando inokulinganiselwa kuphela kwiimeko zokusabela ezimxinwa. Ukongeza, ukulungelelaniswa kunye nokulawulwa kweemeko eziphambili zokusabela (ezifana nebhafu ratio, ukugxilwa kwealkali, isantya sengalo yokuxova kumatshini wokuxova) zimbi kakhulu. Kunzima ukufezekisa uqikelelo oluqikelelweyo lwempendulo ye-etherification kunye nokufunda ukhutshelo ngobuninzi kunye nokungena kwenkqubo yokusabela kwe-etherification ngobunzulu. Iimpawu zenkqubo ye-reactor eshukumisayo njengezixhobo zokusabela zezi: isantya esishukumisayo esikhawulezayo kwimpendulo, isantya sokusabela ngokukhawuleza, izinga eliphezulu lokusetyenziswa kwe-etherizing agent, ukuhanjiswa okufanayo kwee-substituents ze-etherizing, iimeko zokusabela eziphambili ezilungelelanisiweyo nezinokulawulwa.

I-Carboxymethyl cellulose CMC yalungiswa ngezixhobo zokuphendula i-kneader kunye nezixhobo zokusabela kwi-reactor ngokulandelelana. Xa i-kneader isetyenziswe njengesixhobo sokuphendula, ukunyanzeliswa kwesantya kwakuphantsi kwaye isantya sokujikeleza sasiyi-50r / min. Xa i-reactor evuselelayo isetyenziswe njengesixhobo sokuphendula, ukunyamezela kwakuphezulu kwaye isantya sokujikeleza sasiyi-500r / min. Xa i-molar ratio ye-monochloroacetic acid kwi-cellulose monosaccharide yayingu-1: 5: 1, ixesha lokuphendula laliyi-1.5h ku-68℃. Ukuhanjiswa kokukhanya kwe-CMC okufunyenwe ngomatshini wokuxova kwakuyi-98.02% kunye nokusebenza kakuhle kwe-etherification kwakuyi-72% ngenxa yokungena kakuhle kwe-CM kwi-agent etherifying ye-chloroacetic acid. Xa i-reactor evuselelayo yayisetyenziswa njengesixhobo sokusabela, ukukwazi ukunyanzeliswa kwe-arhente ye-etherifying kwakungcono, ukuhanjiswa kwe-CMC kwakungama-99.56%, kunye nokusebenza kakuhle kwe-etherizing reaction yanda ukuya kuma-81%.

I-Hydroxyethyl cellulose HEC yalungiswa nge-kneader kunye ne-reactor eshukumisayo njengesixhobo sokusabela. Xa i-kneader isetyenziswa njengesixhobo sokuphendula, ukusebenza kakuhle kwe-etherizing agent yaba yi-47% kwaye ukunyibilika kwamanzi kwakungalunganga xa ukunyanzeliswa kwe-chloroethyl alcohol etherizing agent kwakungalunganga kwaye umlinganiselo we-molar we-chloroethanol kwi-cellulose monosaccharide wawuyi-3:1 ku-60℃ nge-4h. . Kuphela xa umlinganiselo we-molar we-chloroethanol kwi-cellulose monosaccharides ngu-6: 1, ngaba iimveliso ezinokunyibilika kakuhle kwamanzi zenziwe. Xa i-reactor evuselelayo yayisetyenziswa njengesixhobo sokusabela, ukufikeleleka kwe-agent ye-chloroethyl alcohol etherification agent ibengcono kwi-68℃ nge-4h. Xa umlinganiselo we-molar we-chloroethanol kwi-cellulose monosaccharide yayingu-3: 1, i-HEC eyaphumela ekubeni ibe ne-solubility engcono yamanzi, kunye nokusebenza kakuhle kwe-etherification reaction yanda ukuya kuma-66%.

Ukusebenza kwempendulo kunye nesantya sokusabela kwe-etherizing agent chloroacetic acid iphezulu kakhulu kune-chloroethanol, kwaye i-reactor evuselelayo njengesixhobo sokusabela etherizing ineenzuzo ezicacileyo ngaphezu kwe-kneader, ephucula kakhulu ukusebenza kwe-etherizing reaction. Ukuhanjiswa okuphezulu kwe-CMC kukwabonisa ngokungangqalanga ukuba i-reactor evuselelayo njengesixhobo se-etherizing reaction inokuphucula i-homogeneity ye-etherizing reaction. Oku kungenxa yokuba ikhonkco leselulosi linamaqela amathathu e-hydroxyl kwiringi nganye ye-glucose-yeqela, kwaye kuphela kwimeko edumbe kakhulu okanye enyityilisiweyo zonke iiperi ze-cellulose hydroxyl ze-etherifying agent molecules ziyafikeleleka. I-etherification reaction ye-cellulose idla ngokusabela okungafaniyo ukusuka ngaphandle ukuya ngaphakathi, ngakumbi kwingingqi ye-crystalline ye-cellulose. Xa isakhiwo se-crystal se-cellulose sihlala sicocekile ngaphandle kwempembelelo yamandla angaphandle, i-etherifying agent inzima ukungena kwi-crystalline structure, echaphazela i-homogeneity ye-reaction heterogeneous reaction. Ngoko ke, ngokulungisa i-cotton ecocekileyo (njengokunyusa indawo ethile yekotoni ecocekileyo), ukuphinda kusebenze i-cotton ecocekileyo kunokuphuculwa. Kwinqanaba lokuhlambela elikhulu (i-ethanol / i-cellulose okanye i-isopropyl yotywala / i-cellulose kunye ne-speed-speed-stiring reaction, ngokwengqiqo, umyalelo we-cellulose crystallization zone iya kuncitshiswa, ngeli xesha i-cellulose inokudumba ngamandla, ukwenzela ukuba ukuvuvukala yommandla we-amorphous kunye ne-crystalline cellulose ithande ukuhambelana, Ngaloo ndlela, ukuphinda kusebenze ummandla we-amorphous kunye nommandla we-crystalline ufana.

Ngohlalutyo lwe-infrared spectrum kunye nohlalutyo lwe-X-reyi ye-diffraction, inkqubo ye-etherification reaction ye-cellulose inokuqondwa ngokucace ngakumbi xa i-reactor yokuvuselela isetyenziswa njengesixhobo se-etherification reaction.

Apha, i-infrared spectra kunye ne-X-ray diffraction spectra zahlalutywa. I-etherification reaction ye-CMC kunye ne-HEC yenziwa kwi-reactor evuselelweyo phantsi kweemeko zokusabela ezichazwe ngasentla.

Uhlalutyo lwe-infrared spectrum lubonisa ukuba i-etheration reaction ye-CMC kunye ne-HEC itshintsha rhoqo kunye nokwandiswa kwexesha lokuphendula, iqondo lokutshintshwa lihlukile.

Ngohlalutyo lwepatheni ye-X-ray ye-diffraction, i-crystallinity ye-CMC kunye ne-HEC ithandeka kwi-zero kunye nokwandiswa kwexesha lokuphendula, ebonisa ukuba inkqubo ye-decrystallization ifunyenwe kwinqanaba le-alkalization kunye nenqanaba lokufudumeza phambi kokuphendula kwe-etherification yekotoni esulungekisiweyo. . Ke ngoko, i-carboxymethyl kunye ne-hydroxyethyl etherification reactivity yomqhaphu osulungekileyo ayisathintelwa ikakhulu yicrystallinity yomqhaphu osulungekileyo. Inxulumene nokufikeleleka kwearhente ye-etherifying. Ingaboniswa ukuba i-etherification reaction ye-CMC kunye ne-HEC iqhutywa nge-reactor eshukumisayo njengesixhobo sokusabela. Ngaphantsi kwesantya esiphezulu sokuvuselela, kunenzuzo kwinkqubo yokucoca i-cotton esulungekileyo kwinqanaba le-alkalization kunye nenqanaba lokufudumeza ngaphambi kokusabela kwe-etherification, kwaye inceda i-ejenti ye-etherification ukuba ingene kwi-cellulose, ukuze kuphuculwe ukusebenza kakuhle kwe-etherification reaction kunye nokufana okufanayo. .

Ukuqukumbela, olu phononongo lugxininisa impembelelo yamandla ashukumisayo kunye nezinye izinto ekusebenzeni kakuhle kokusabela ngexesha lenkqubo yokusabela. Ngoko ke, isindululo solu phononongo sisekelwe kwezi zizathu zilandelayo: Kwinkqubo yokusabela kwe-etheration ene-heterogeneous, ukusetyenziswa komlinganiselo omkhulu wokuhlambela kunye nobukhulu obuxhokonxayo obuphezulu, njl. ukuhanjiswa Kwinkqubo ethile yokusabela kwe-etheration ethile, ukusebenza okuphezulu kweselulosi ye-ether ene-ether ephantse ibefanayo yokusasazwa kwezinto ezibambeleyo kunokulungiswa ngokusebenzisa i-reactor eshukumisayo njengesixhobo sokusabela, nto leyo ebonisa ukuba isisombululo se-cellulose etere esimanzi sinokudluliselwa okuphezulu, okubaluleke kakhulu ukwandisa iipropati. kunye nemisebenzi ye-cellulose ether. Umatshini wokuxova usetyenziswa njengezixhobo zokusabela ukufunda ukusabela kwe-etherification yomqhaphu osulungekileyo. Ngenxa yoxinzelelo oluphantsi lokuzamisa, ayilunganga ekungeneni kwe-etherification agent, kwaye ineziphene ezithile ezifana nenani eliphezulu leempendulo ezisecaleni kunye nokusasazwa okulambathayo okufanayo kwe-etherification substituent.