N-lauryl-n-methyl Glucose Amide Adsorption Kinetics And Microemulsion Phase Behavior

This thesis contains four parts, Part I. Progress in the synthesis, basic properties and the association structure of N-acyl-N-alkylglucamide; Part II. Adsorption equilibrium and kinetics of N-lauroyl-N-methylglucamide (MEGA-12) with and without cetyltrimethylammonium bromide (CTAB) at the air/water interface; Part III. Studies on the phase behavior of the MEGA-12 based middle phase microemulsion; Part IV. Studies on the middle phase microemulsion of alkyl polyglucaside (C12G1.46)/ n-butanol/ oil/ water system.Part I. Progress in the synthesis, basic properties and the association structure of N-acyl-N-alkylglucamide1. The synthetical methods and the basic properties, such as the Krafft point, the crystal structure, the equilibrium adsorption, CMC,γCMC of MEGA-12 were introduced.2. The adsorption kinetics of MEGA-n on the air/water interface was reviewed.3. The research progress in the phase behavior of the MEGA-n based microemulsion was reviwed.Part II. Adsorption equilibrium and kinetics of N-lauroyl-N-methyl glucamide (MEGA-12) with and without cetyltrimethyl ammonium bromide (CTAB) at the air/water interface1. The principle and methods for the determination of surface tension were introduced, especially the mechanism, device and procedure of the determination of dynamic surface tension by the maximum bubble pressure method (MBPM) were introduced in detail.2. The adsorption equilibriums of MEGA-12 and MEGA-12/CTAB solutions were studied. And the CMC,γCMC, the adsorption surplus and the average area per molecule were calculated.3. The adsorption kinetics and the influencing factors of MEGA-12 at the air/water interface were determined by MBPM. The results show that the adsorption process is diffusion-controlled when the concentration of surfactant is small. The adsorption process is diffusion-controlled at the initial of adsorption and turns to adsorption-controlled at the end of the adsorption when the concentration is large. The dynamic surface tension (DST) declines more quickly when the concentration of MEGA-12 becomes larger, and the apparent diffusion coefficients decrease, as the adsorption energy increases. The DST decreases notablely when the temperature rises. The addition of n-butanol, n-pentanol or ionic liquid has notable influence on the DST. The longer the alcohol carbon chain length, the more quickly the DST declines. At the end of the adsorption the DST declines more slowly.4. The DST curves of MEGA-12/CTAB mixed system indicate that the synergism domain the DST of the mixed system when the molar ratio of MEGA-12/ CTAB is larger. The synergism weakens and even disappears as the molar ratio of MEGA-12/ CTAB decreases.Part III. Studies on the phase behavior of the MEGA-12 based middle phase microemulsionThe phase behavior of the quaternary microemulsion system MEGA-12/ alcohol/ alkane/ water was studied with Winsor type,δ-γfishlike andε-βfishlike phase diagrams.1. From Winsor phase diagram, the alcohol content range from forming to disappearing of the middle phase microemulsion and the volume of each phase can be observed. The results show that the MEGA-12 concentration, alcohol and oil have notable influence on the phase behavior. The larger the MEGA-12 concentration, the larger the volume of the middle phase, that is, the larger the solubilization power of the microemulsion system, and the larger the minimum alcohol content needed to form middle phase microemulsion. However, the alcohol width increases and then decreases along with the increase in the MEGA-12 concentration. The shorter the oil carbon chain length, the larger the solubilization power.2. Theδ-γfishlike phase diagram of above quaternary microemulsion system was plotted.The fish head in theδ-γfishlike phase diagram is upward, which indicates that part alcohol dissolves in the interfacial layer and the other part dissolves in oil. The composition of the HLB plane can be calculated by using the HLB equation. The solubilities of surfactant and alcohol in the oil phase, the coordinates of the fish head and fish tail can be obtained by corresponding equations. The abscissa (γE) of theδ-γfishlike phase diagram indicates the minimum total amount of surfactant and alcohol to solubilize equal amount of oil and water into a single phase microemulsion. The smaller theγE value is, the larger the solubilization power is.The shorter the oil carbon chain length or the longer the alcohol carbon chains are, the larger the solubilization power is. The NaCl concentration has a little influence on the solubilization power.3. Theε-βfishlike phase diagram of above quaternary microemulsion system was also studied.The fish head is downward and the fish tail is upward in theε-βfishlike phase diagram. The composition of the HLB plane can be obtained by using theε-βHLB plane equation, and other physicochemical parameters, such as the solubilities of surfactant and alcohol in the oil phase can be obtained by using corresponding equations. The HLB plane equation is a straight line. The coordinates (βE,εE) of the fish tail reveal the mass fractions of surfactant and alcohol in the total system, respectively, while equal amounts of water and oil are solubilized in a single phase.βE andεE are better thanγE in evaluating the solubilization of the system.Part IV. Studies on the middle phase microemulsion of alkyl polyglucoside (C12G1.46)/ n-butanol/ oil/ water systemThe microemulsion phase behavior for system C12G1.46/ n-butanol/ oil/ water was studied by Winsor type,δ-γfishlike andε-βfishlike phase diagrams, respectively. The phase inversions Winsor I (2)â†'III (3)â†'II (2 ) can be observed from all three kinds of phase diagrams.From the Winsor phase diagram, it can be seen the order of the solubilization power of the microemulsion system is methylene chloride > carbon tetrachloride > o-dichlorobenzene > toluene > n-hexane, while the concentration of APG solution is nearly the same. The minimum alcohol concentration to form middle phase microemulsion is o-dichlorobenzene > methylene chloride > toluene > n-hexane > carbon tetrachloride.Fromδ-γfishlike phase diagram, the order of the abscissa (γE) of the fish tail is methylene chloride < carbon tetrachloride < toluene < o-dichlorobenzene < n-hexane, that is the order of the solubilization power of the system is methylene chloride > carbon tetrachloride > toluene > o-dichlorobenzene > n-hexane.From theε-βfishlike phase diagram, the order of the abscissa (βE) of its fish tail is methylene chloride < carbon tetrachloride < o-dichlorobenzene < toluene < n-hexane, and the order of y axis is carbon tetrachloride < methylene chloride < toluene < o-dichlorobenzene < n-hexane. The two orders indicate that oils have notable influence on the amounts of both surfactant and alcohol in forming single phase diagram.