Cov khoom ntawm Alkyl Polyglucosides

Zoo ib yam li polyoxyethylene alkyl ethers,alkyl polyglycosidesfeem ntau yog technical surfactants. Lawv raug tsim los ntawm ntau hom Fischer synthesis thiab muaj kev faib tawm ntawm hom nrog ntau qib ntawm glycosidation qhia los ntawm tus nqi n-tus nqi. Qhov no txhais tau tias yog qhov piv ntawm tag nrho cov molar cov piam thaj rau cov molar pes tsawg ntawm cov roj cawv hauv alkyl polyglucoside, coj mus rau hauv tus account qhov nruab nrab molecular hnyav thaum fatty cawv sib xyaw ua haujlwm. Raws li twb tau hais lawm feem ntau ntawm alkyl polyglucosides ntawm qhov tseem ceeb rau daim ntawv thov muaj qhov nruab nrab n-tus nqi ntawm 1.1-1.7. Yog li, lawv muaj alkyl monoglucosides thiab alkyl diglucosides ua cov khoom tseem ceeb, nrog rau cov nqi me me ntawm alkyl triglucosides, alkyl tetraglucosides, thiab lwm yam mus txog alkyl octaglucosides dua li ntawm oligomers, me me (feem ntau yog 1-2%) ntawm cov roj cawv. cov synthesis polyglucose, thiab ntsev, feem ntau yog vim catalysis (1.5-2.5%), yog ib txwm muaj. Cov nuj nqis raug xam nrog rau cov teeb meem nquag. Whereas polyoxyethylene alkyl ethers los yog ntau lwm yam ethoxylates tej zaum yuav raug txhais unambiguously los ntawm ib tug faib ntawm molecular luj, ib tug analogous piav qhia yog tsis muaj txhais tau tias txaus rau alkyl polyglucosides vim hais tias sib txawv isomerism ua rau ib tug ntau ntau complex ntau yam ntawm cov khoom. Qhov sib txawv ntawm ob chav kawm surfactant ua rau muaj cov khoom sib txawv uas tshwm sim los ntawm kev sib cuam tshuam ntawm lub taub hau nrog dej thiab ib feem ntawm ib leeg.

Cov pab pawg ethoxylate ntawm polyoxyethylene alkyl ether cuam tshuam nrog dej, tsim hydrogen bonds ntawm ethylene oxygen thiab dej molecules, li no tsim micellar hydration shells qhov twg cov txheej txheem ntawm dej ntau dua (qis entropy thiab enthalpy) dua nyob rau hauv tej dej. Cov qauv hydration yog heev dynamic. Feem ntau ntawm ob thiab peb cov dej molecules yog txuam nrog txhua pawg EO.

Kev txiav txim siab txog glucosyl headgroups nrog peb OH ua haujlwm rau monoglucoside lossis xya rau diglucoside, alkyl glucoside tus cwj pwm yuav tsum txawv ntawm cov polyoxyethylene alkyl ethers. Dhau li ntawm kev sib raug zoo nrog dej, kuj tseem muaj zog ntawm cov surfactant headgroups hauv micelles nrog rau lwm cov theem. Qhov sib piv polyoxyethylene alkyl ethers ib leeg yog cov kua lossis cov khoom tawg qis, alkyl polyglucosides yog cov khoom melting ntau dua vim muaj kev sib txuas ntawm cov hydrogen sib txuas ntawm cov neeg nyob sib ze glucosyl. Lawv tso tawm cov thermotropic kua crystalline cov yam ntxwv, raws li yuav tau tham hauv qab no. Intermolecular hydrogen bonds ntawm cov pab pawg neeg tseem yog lub luag haujlwm rau lawv qhov kev sib piv qis hauv dej.

Raws li rau cov piam thaj nws tus kheej, kev sib cuam tshuam ntawm pawg glucosyl nrog cov dej molecules nyob ib puag ncig yog vim muaj kev sib txuas ntawm hydrogen ntau. Rau cov piam thaj, qhov concentration ntawm tetrahedrally txheej txheem dej molecules yog siab dua hauv dej ib leeg. Yog li, cov piam thaj, thiab tej zaum kuj yog alkyl glucosides, tuaj yeem raug cais raws li "tus tsim qauv," tus cwj pwm zoo ib yam li cov ethoxylates.

Nyob rau hauv kev sib piv rau tus cwj pwm ntawm ethoxylate micelle, qhov zoo interfacial dielectric tas li ntawm alkyl glucoside yog ntau dua thiab zoo ib yam li cov dej ntau dua li ntawm ethoxylate. Yog li, thaj av ib ncig ntawm lub taub hau ntawm alkyl glucoside micelle yog aqueous-zoo li.