The Dynamic Surface Tension Of The Surfactant, The Middle-phase Microemulsion And Microemulsion Enzymatic Reaction

Based on the various use of surfactants in the fields of spin, food, oil, agriculture,forest, transport, environment protect and so on, the adsorption kinetics of BTAC onthe interface of air/water, the middle phase behavior of AEO-9, and the esterificationreaction catalyzed by lipase in C₁₂G_1.50/n-butanol/cyclohexane/water W/O systemwere studied.Part one of the thesis, progress of the research in dynamic surface tension,middle phase microemulsion and esterification reaction catalyzed by lipase inmicroemulsion were reviewed, the maximum bubble pressure method used todetermine dynamic surface tension was introduced. The importance of dynamicsurface tension in industry was strethened. The research processes in the dynamicsurface tension were summarized. The classification of the microemulsion and theresearch method, especially theδ-γfishlike phase diagram, were introduced andsummarized. The research history, the character of esterification reaction, especiallythe character of esterification reaction catalyzed by lipase, the surfactants commonlyused in sterification reaction and the mechanism of esterification reaction etc. wereintroduced.Partâ…¡maximum bubble pressure method (MBPM) was used to determine thedynamic surface tension of aqueous solution of BTAC. Adsorption kinetics of BTACat the air/water interface and influencing factors were studied. The results show thatthe adsorption process is controlled by a diffusion step when the aqueous is dilute; theadsorption process is controlled by a diffusion step at the start and toward the end itchanges to an activation mechanism with an adsorption barrier, when theconcentration is large. The diffusion parameter Da decreases with the increase in theconcentration of BTAC. This may be explained that the surface pressure aggravatesand the molecules are more and more difficult to run into "empty" surface, so it ismore and more difficult for BTAC molecules to adsorb at the surface. The dynamicsurface tension declines obviously when the temperature rises. In the aqueous solution containing n-butanol or n-pentanol the dynamic surface tension declinesquickly because of the synergism of the two kinds molecules. And after that thesurface absorbed certain BTAC the dynamic surface intense of aqueous declinesslower. The addition of no-organic salt affects the DST observiously, which may bedue to the salt out effect.Partâ…¢the middle phase behavior of AEO/ n-butanol/ alkane/ watermicroemulsion system was studied byδ-γfishlike phase diagram. A series of phaseinversions were observed: Winsorâ… ((?))→Ⅲ(3)→Ⅱ((?) ), when increasingδat constantγin the fishlike phase diagram. Some, physicochemical parameters can be calculatedby HLB plane equation. Additionally, the influencing factors of different oils, alcoholsand salt solutions with different concentrations were investigated. It was found thatthe alcohols with longer hydrocarbon chains, need less alcohol to form middle phasediagram, and the solubilization capacity is larger. The shorter hydrocarbon chain ofalkanes, the larger solubilization of the microemulsion system. The NaClconcentrations facilitate the formation of the middle phase microemulsion.Partâ…£, the Esterification Reaction Catalyzed by Lipase in C₁₂G_1.50/n-Butanol/Cyclohexane/Water W/O System was studied. The esterification reaction and itsinfluencing factors of hexanoic acid with n-butanol, catalyzed by lipaseNovozym100T, were studied in water-in-oil microemulsions formed by alkylpolyglucoside C₁₂G_1.50/n-butanol/cyclohexane/water system. The result shows thatthe initial rate V₀ of the esteriflcation reaction increases as hexanoic acidconcentration increases; and the initial rate V₀ decreases as n-butanol concentrationincreases and then reaches a plateau region. This may be explained by the formationof lipase-butanol complex. The initial rate V₀ of the esterification reaction increaseswith the increase in the concentration of n-hexanoic acid, when the volume ofn-butanol is fixed. The C₁₂G_1.50 has little effect on the initial rate V₀, when itsconcentration is small; and the intial rate V₀ increases when its concentration is large.Fix the concentration of C₁₂G_1.50, the initial rate V₀ decreases as the n-butanolconcentratioh increases, when the n-hexanoic acid is small; but V₀ increases as the n-butanol concentration increases when the n-hexanoic acid is large. The initial rateV₀ decreases along with the increase in the total concentrations of C₁₂G_1.50 andn-butanol, when the n-hexanoic acid aqueous is thin; and the initial rate V₀ increasesalong with the increase in the total concentrations when the n-hexanioc acid aqueousis thick.