Kinetics of the Esterification Reaction Catalyzed by Lipase in W/O Microemulsions of Alkyl Polyglucoside

A novel kinetic mechanism of esterification reaction of 1-hexanoic acid with 1-butanol, catalyzed by lipase, was studied in water-in-oil microemulsions. The microemulsions were formed by alkyl polyglucoside C10G1.54/1-butanol / cyclohexane/phosphate buffer solution. The result shows that when the ratio of mol concentration of 1-butanol to 1-hexanoic acid is about 3.0, the initial rate V0 get the maximum values. This phenomenon was explained by the modified fishlike phase diagrams.

Studies on Phase Behavior of Alkyl Polyglucoside Based on Microemulsions with Modified Fishlike Phase Diagram

The three-phase behavior in the quaternary system of an alkyl (C8/10- or C12/14-) polyglucoside / 1-butanol / n-octane / water has been studied at 40 ℃ with the modified fishlike phase diagram, which is presented by us for the first time. The mass fraction of 1-butanol in the hydrophile-lipophile balanced interfacial layer, AS, the coordinates of the start point B and the end point E of the phase diagram, and the solubilities of alkyl polyglucoside and 1-butanol in n-octane phase were calculated. The solubilization of the microemulsion was also discussed.

Adsorption Kinetics of Alkyl Polyglucoside at the Air-Solution Interface

The air-solution equilibrium tension ge and dynamic surface tension gt, of nonionic surfactant alkyl polyglucoside have been studied. ge was measured by the Wilhelmy method with Krüss K12 tensiometer. The CMC and the surface excesses Γwere determined from the surface tension vs. concentration curve. The gt decays were measured in the range 0.2～20 s using a maximum bubble pressure instrument and analyzed with the Ward and Tordai equation.

Middle-phase microemulsions of green surfactant alkyl polyglucosides

The microemuision behavior in the quaternary system alkyl polyglucoside(C_8G_(1.46), C_(10)G_(1.54))/1-butanol/cyclohexane/water has been studied at 40℃ with the alcoholconcentration scanning and the fishlike phase diagram methods. Increasing δ at a constant γ causesa phase inversion from an oil-in-water microemuision in contact with excess oil (Winsor Ⅰ or 2 )to a water-in-oil microemuision in contact with excess water (Winsor Ⅱ or 2) via a middle-phasemicroemuision in contact with excess oil and water (Winsor Ⅲ or 3). By using the simple massbalance equation and the HLB plane equation, the mass fraction of 1-butanol in the interfaciallayer, S_2~s, the monomeric solubilities of APG and 1-butanol, S_1 and S_2, in the oil phase, andthe mass fractions of APG and 1-butanol in the interfacial layer (C_1 and C_2) have been calculated,respectively. The effects of different alcohols, aqueous media arid oils on the phase behavior andthe composition of the interfacial layer are also investigated. It is found that the alcohols withlonger hydrocarbon chain, oil molecules with smaller molecular volume and the addition of inorganicsalt can increase the solubilization of the microemulsions .

Unique Dielectric Behavior of Alkyl Polyglucoside/n-butanol/n-hexane/water System

The pseudotertiary phase diagram of the microemulsion system alkyl polyglucoside/n-butanol/n-hexane/water was plotted at （30.0±0.1） ℃. The dielectric measurements, including permittivity, conductivity, relaxation strength, characteristic relaxation time, etc,, were applied to investigate the microstructure of the system. Unique dielectric relaxations were observed over the frequency range of 5-10^7 Hz, taking place possibly through an interracial polarization mechanism. According to the results obtained from dielectric spectroscopy, the structures of the microemulsion O/W, BC and W/O were determined, and some dielectric and phase parameters were calculated.

An efficient and facile procedure for synthesis of octyl polyglucoside

Nonionic surfactant alkyl polyglucoside （APG） was prepared by direct glycosidation of alkyl alcohol with glucose in the presence of sulfate acid-silica gel （H2SO4/SiO2） as solid acidic catalyst. The quantity of catalyst was only of 1 wt%, based on the glucose, and the conversion of glucose was close to 100% at 110 ℃ in 1.5 h. The product was characterized by FT-IR, mass and ^1H NMR spectra. The degree of polymerization （DP） of the glucose in the product was 1.37, and critical micelle concentration （CMC） of product was only 0.0104 wt%.