izindaba

Izidingo zokuklama zesitshalo sokukhiqiza i-alkyl glycoside ezisekelwe ku-Fisher synthesis zincike kakhulu ohlotsheni lwe-carbohydrate esetshenzisiwe kanye nobude beketango lotshwala obusetshenzisiwe.Ukukhiqizwa kwama-alkyl glycosides ancibilika emanzini asekelwe ku-octanol/decanol kanye ne-dodecanol/tetradecanol kwethulwa okokuqala. .I-Alkyl polyglycosides, ku-DP enikeziwe, engancibiliki emanzini ngenxa yotshwala obusetshenzisiwe(inani lama-athomu C ku-alkyl chian≥16) abhekwana nawo ngokuhlukana.
Ngaphansi kwesimo se-alkyl polyglucoside synthesis eyenziwe nge-asidi, imikhiqizo yesibili efana ne-polyglucose ether kanye nokungcola okunemibala kuyakhiqizwa.I-Polyglucose iyinto e-amorphous eyakhiwe yi-glycosyl polymerization ngesikhathi senqubo yokuhlanganisa.Uhlobo nokugxila kokusabela kwesibili kuncike kumingcele yenqubo. , njengezinga lokushisa, ingcindezi, isikhathi sokuphendula, i-catalyst, njll.Enye yezinkinga ezixazululwe ukuthuthukiswa kokukhiqizwa kwe-alkyl polyglycosides yezimboni eminyakeni yamuva ukunciphisa ukwakheka kwemikhiqizo yesibili ehlobene nokuhlanganiswa.
Ngokuvamile, i-alkyl glycosides esekelwe ku-alcohol yamaketanga amafushane (C8/10-OH) kanye ne-DP ephansi (i-alcohol overdose) inezinkinga ezincane zokukhiqiza.Esigabeni sokusabela, ngokwanda kotshwala obuningi, ukukhiqizwa kwemikhiqizo yesibili kuncipha.Inciphisa ukucindezeleka okushisayo futhi isuse utshwala obuningi ngesikhathi sokwakhiwa kwemikhiqizo ye-pyrolysis.
I-Fisher glycosidation ingachazwa njengenqubo lapho i-glucose isabela ngokushesha ngokuqhathaniswa esinyathelweni sokuqala futhi ukulingana kwe-oligomer kufinyelelwa.Lesi sinyathelo silandelwa ukuwohloka kancane kwe-alkyl glycosides.Inqubo yokuwohloka ihilela izinyathelo ezifana ne-dealkylation kanye ne-polymerization, okuthi, at ukugxila okukhuphukile, kwakha i-polyglucose ezinzile ngokwe-thermodynamically.Ingxube yokusabela eyeqa isikhathi sokusabela esilungile ibizwa ngokuthi i-overreaction.
Ukulahleka kwezinto ezisebenzayo ze-alkyl glucoside enhlanganisela yokusabela kunobudlelwano obuhle nokwakheka kwe-polyglucose.Endabeni yokusabela okweqile, ingxube yokusabela kancane kancane iba i-polyphase futhi ngenxa yemvula ye-polyglucose.Ngakho-ke, ikhwalithi yomkhiqizo kanye nesivuno somkhiqizo kuthinteka kakhulu ngesikhathi sokuqedwa kokusabela.Kuqala nge-glucose eqinile, ama-alkyl glycosides emikhiqizweni yesibili aba. okungaphansi kokuqukethwe, okuvumela ezinye izingxenye ze-polar (i-polyglucose) kanye nama-carbohydrate asele ukuthi ahlungwe kunhlanganisela esebenzayo engakaze isabele ngokugcwele.
Enqubweni elungiselelwe, ukugxila komkhiqizo we-etherification kuphansi kakhulu (kuye ngokuthi izinga lokushisa lokusabela, isikhathi, uhlobo lwe-catalyst kanye nokugxila, njll.).
Umfanekiso wesi-4 ubonisa inkambo evamile yokusabela okuqondile kwe-dextrose kanye notshwala obunamafutha (C12/14-OH).
Umfanekiso 4. Ibhalansi enkulu yenqubo ye-glycosidation
Ukushisa nokucindezela kwemingcele yokusabela kuhlobene eduze komunye nomunye ekuphenduleni kwe-fischer glycation.Ukuze ukhiqize i-alkyl polyglycosides ngemikhiqizo ephansi yesibili, ingcindezi kanye nokushisa kufanele kuhambisane nomunye nomunye futhi kulawulwe ngokuqinile.
I-Alkyl polyglycosides iphansi emikhiqizweni yesibili ebangelwa izinga lokushisa eliphansi lokusabela (<100℃) ku-acetalization.Kodwa-ke, amazinga okushisa aphansi aholela ezikhathini zokusabela ezinde (kuye ngobude beketango lotshwala) kanye nokusebenza kahle kwe-reactor ethile ethile.Amazinga okushisa aphakeme uma kuqhathaniswa (>100℃, imvamisa engu-110-120℃) angaholela ekushintsheni kombala wamacarbohydrate.Ngokususa imikhiqizo yokusabela ebilisa kancane (amanzi aku-direct synthesis, utshwala beketanga elifushane kunqubo ye-transacetalization) kwingxube yokusabela, ukulingana kwe-acetalization kugudluzelwa ohlangothini lomkhiqizo.Uma inani elikhulu lamanzi likhiqizwa ngeyunithi ngayinye yesikhathi, isibonelo ngamazinga okushisa aphezulu, kufanele kwenziwe amalungiselelo okukhishwa okusebenzayo kwalawa manzi engxubeni yokusabela.Lokhu kunciphisa ukusabela kwesibili (ikakhulukazi ukwakheka kwe-polydextrose) okwenzeka lapho kukhona amanzi.Ukusebenza kahle kokuhwamuka kwesiteji sokusabela akuncikile kuphela ecindezelweni, kodwa nendawo yokuhwamuka, njll.Izingcindezi ezijwayelekile zokusabela ku-transacetalization kanye nokwahluka kwe-direct synthesis kuphakathi kuka-20 no-100mbar.
Esinye isici esibalulekile sokuthuthukisa ukuthuthukiswa kwama-catalysts akhethiwe enqubweni ye-glycosidation, ngaleyo ndlela kuvimbela, isibonelo, ukwakheka kwe-polyglucose kanye ne-etherification.Njengoba sekushiwo kakade, i-acetal noma i-acetal ehlanekezelwe ku-Fischer synthesis is catalyzed by acids.Ngokomthetho, noma iyiphi i-asidi yamandla anele ifanelekela le njongo, njenge-sulfuric acid, i-p-toluene ne-alkyl benzenesulfonic acid kanye ne-sulfonic succinic acid.Izinga lokusabela lincike ku-acidity kanye nokugcwala kwe-asidi etshwaleni.Ukusabela okwesibili okungabuye kufakwe ama-acids ( isb, ukwakheka kwe-polyglucose) kwenzeka kakhulu esigabeni se-polar (amanzi okulandelela) wengxube yokusabela, futhi amaketanga e-alkyl angancishiswa ngokusebenzisa ama-hydrophobic acid (isb., i-alkyl benzenesulfonic acid) ancibilika kakhulu esigabeni esincane se-polar ingxube yokusabela.
Ngemva kokusabela, i-acid catalyst iyancipha ngesisekelo esifanele, njenge-sodium hydroxide ne-magnesium oxide.Ingxube yokusabela engathathi hlangothi iyisixazululo esiphuzi esiphaphathekile esiqukethe amaphesenti angama-50 kuya kwangu-80 ama-alcohols anamafutha.Okuqukethwe kotshwala okunamafutha amaningi kungenxa yesilinganiso se-molar sama-carbohydrate notshwala obunamafutha.Lesi silinganiso siyalungiswa ukuze kutholwe i-DP ethile ye-alkyl polyglycosides yezimboni, futhi ngokuvamile iphakathi kuka-1:2 no-1:6.
Utshwala obunamafutha amaningi bususwa nge-vacuum distillation.Izimo zomngcele ezibalulekile zihlanganisa:
– Insalela okunamafutha utshwala okuqukethwe kufanele kube<1% ngoba okunye
ukuncibilika okuhlakaniphile kanye nephunga kuthinteka kabi.
- Ukunciphisa ukwakheka kwemikhiqizo ye-pyrolysis engafuneki noma izingxenye ezishintsha umbala, ukucindezelwa kokushisa kanye nesikhathi sokuhlala komkhiqizo oqondiwe kufanele kugcinwe siphansi ngokusemandleni ngokuncika kubude beketango lotshwala.
- Ayikho i-monoglycoside okufanele ingene ku-distillate ngoba i-distillate igaywa kabusha ekuphenduleni njengotshwala obunamafutha ahlanzekile.
Endabeni ye-dodecanol/tetradecanol, lezi zidingo zisetshenziselwa ukususwa kotshwala obunamafutha amaningi, okwanelisa kakhulu ngokudilizwa kwezigaba eziningi.Kubalulekile ukuqaphela ukuthi njengoba okuqukethwe kotshwala obunamafutha kuncipha, i-viscosity iyanda kakhulu.Lokhu ngokusobala kuphazamisa ukushisa nokudluliswa kwenqwaba esigabeni sokugcina sokukhipha isisu.
Ngakho-ke, ama-evaporators amancane noma amafushane akhethwa.Kulawa ma-evaporator, ifilimu ehamba ngomshini inikeza ukusebenza kahle kokuhwamuka kanye nesikhathi esifushane sokuhlala komkhiqizo, kanye ne-vacuum enhle.Umkhiqizo wokugcina ngemva kokukhishwa kwe-distillation cishe i-alkyl polyglycoside emsulwa, enqwabelana njengento eqinile enephuzu lokuncibilika lika-70℃ kuya ku-150℃.Izinyathelo eziyinhloko zenqubo ye-alkyl synthesis zifinyezwa njengoMfanekiso 5.
Umfanekiso 5. Umdwebo wokugeleza owenziwe lula wokukhiqizwa kwe-alkyl polyglycosides ngokusekelwe emithonjeni ehlukene yama-carbohydrate.
Ngokuya ngenqubo yokukhiqiza esetshenzisiwe, ukugeleza komjikelezo owodwa noma emibili yotshwala kunqwabelana ekukhiqizeni i-alkyl polyglycoside;uphuzo oludakayo olunamafutha amaningi, kanti utshwala obuyi-short-chain lungacishe lutholakale ngokuphelele.Lobu tshwala bungase buphinde busetshenziswe ekuphenduleni okulandelayo.Isidingo sokuhlanza noma imvamisa okufanele kwenziwe ngayo izinyathelo zokuhlanza kuncike ekungcoleni okuqoqwe otshwaleni.Lokhu kuncike kakhulu kwikhwalithi yezinyathelo zenqubo eyandulele (isibonelo ukusabela, ukususwa kotshwala).
Ngemva kokususwa kotshwala obunamafutha, into esebenzayo ye-alkyl polyglycoside incibilika ngokuqondile emanzini ukuze kwakhiwe i-viscous ephezulu engu-50 kuya ku-70 % we-alkyl polyglycoside paste.Ezinyathelweni zokucwenga ezilandelayo, lokhu kunamathisela kusetshenzwa kube umkhiqizo wekhwalithi egculisayo ngokuhambisana nezidingo ezihlobene nokusebenza.Lezi zinyathelo zokucwenga zingase ziqukathe ukufiphala komkhiqizo, ukulungiswa kwezici zomkhiqizo, njengenani le-Ph nokuqukethwe kwento esebenzayo, kanye nokuqiniswa kwe-microbial.Emibhalweni yelungelo lobunikazi, kunezibonelo eziningi zokucwecwa kwe-reductive ne-oxidative kanye nezinqubo zezigaba ezimbili zokucwecwa kwe-oxidative kanye nokuqiniswa kwe-reductive.Umzamo kanye nezindleko ezihilelekile kulezi zinyathelo zenqubo zokuthola izici ezithile zekhwalithi, njengombala, zincike ezidingweni zokusebenza, ezintweni zokuqala, i-DP edingekayo kanye nekhwalithi yezinyathelo zenqubo.
Umfanekiso wesi-6 ubonisa inqubo yokukhiqiza yezimboni yamaketanga amade e-alkyl polyglycosides (C12/14 APG) ngokuhlanganisa okuqondile)
Umfanekiso 6. Inqubo ejwayelekile ye-industrial-scale glycosidation ye-C12 14 APG


Isikhathi sokuthumela: Oct-13-2020