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Microemulsion System (microemulsion + system)

Distribution by Scientific Domains
Chemistry70%

Selected Abstracts

SHELF LIFE OF FRESH NOODLES AS AFFECTED BY THE FOOD GRADE MONOLAURIN MICROEMULSION SYSTEM

JOURNAL OF FOOD PROCESS ENGINEERING, Issue 5 2008
XIAOWEI FU
ABSTRACT Food grade monolaurin (the glycerol monoester of lauric acid) microemulsions (MMEs) based on multicomponent mixtures and the effects of MMEs on the shelf life of fresh noodles were studied. A microemulsion system consisting of monolaurin (M), surfactants (Tween 20 and Tween 80, Wenzhou Qingming Chemical Engineering Company, Wenzhou, Zhejiang, China ) and cosurfactant (pentanol and dodecanol) dispersed in distilled water was used. The influence of surfactants on the phase behavior was studied in this article. Subsequently, two MMEs with large oil in water regions have demonstrated the enhanced antimicrobial activities against Bacillus subtilis, Escherichia coli, Aspergillus niger and Penicillium digitatum, compared to monolaurin (M) alone. In addition, the shelf life of fresh noodles prepared with monolaurin (M) alone was about 4 days, whereas MMEs extended shelf life by 10 days at least when stored at 37C. PRACTICAL APPLICATIONS The effect of monolaurin microemulsion (MME) as antimicrobial agents in foods, especially those neutral foods such as noodles, is obvious, and MME has demonstrated a much longer shelf life of fresh noodles than M alone. In addition, for those neutral foods other than fresh noodles, the application of MMEs can also be studied. [source]

Formation of a Novel Type of Reverse Microemulsion System and Its Application in Synthesis of the Nanostructured La0.95Ba0.05MnAl11O19 Catalyst.

CHEMINFORM, Issue 47 2004
Fei Teng
Abstract For Abstract see ChemInform Abstract in Full Text. [source]

Influence of cosurfactant in microemulsion systems for color removal from textile wastewater

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2005
Leocadia Terezinha Cordeiro Beltrame
Abstract Microemulsion systems have proved very efficient in color removal from textile wastewater using n -butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n -butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (,E*ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n -butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n -butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry [source]

Microemulsion copolymerization of styrene and acrylonitrile with n -butanol as the cosurfactant

JOURNAL OF POLYMER SCIENCE (IN TWO SECTIONS), Issue 1 2005
Yuanchang Shi
Abstract The microemulsion copolymerization of styrene and acrylonitrile in an n -butanol/cetyltrimethylammonium bromide/oil/water microemulsion system was studied. The solubilization sites of the two monomers were determined with an NMR technique. The results showed that the solubilization behaviors of the two monomers were quite different. Most of the styrene was solubilized in the palisade layer of the microemulsion, whereas the acrylonitrile had an equilibrium distribution in the aqueous phase and palisade layer of the microemulsion. The reactivity ratios of styrene and acrylonitrile in the microemulsion system were different from those in other media. The effect of the monomer feed composition on the copolymerization kinetics was investigated, and the mechanism of nucleation of the latex particles was examined. The experimental results showed that the copolymerization loci were changed from the microemulsion droplets to the aqueous phase when the concentration of acrylonitrile in the monomer feed reached approximately 80%; this could be further proved by the effect of the monomer feed composition on the copolymerization kinetics. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 203,216, 2005 [source]

Phase behaviour of microemulsions with lubricant base oil as the oil phase

LUBRICATION SCIENCE, Issue 7 2009
Ya Lu
Abstract Appropriate surfactants and co-surfactants were chosen to prepare a microemulsion system with lubricant base oil as the oil phase. The phase behaviour of the microemulsion at different temperatures and at different oil/water mass ratios was assessed on the basis of conductivity measurements. Microemulsions and a bi-continuous microstructure were obtained when the oil/water mass ratio was below 0.33. An analysis of the conductivity behaviour of the microemulsions revealed that different conductive mechanisms are operative at different water contents. Activation energies (,E) were determined. The results showed that ,E increases with increasing water content. The data and the derived relationship provided a basis for preparing metalworking microemulsions. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Influence of cosurfactant in microemulsion systems for color removal from textile wastewater

JOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 1 2005
Leocadia Terezinha Cordeiro Beltrame
Abstract Microemulsion systems have proved very efficient in color removal from textile wastewater using n -butyl alcohol as cosurfactant. The cosurfactant has a very important role in microemulsified systems, as it is responsible for their stability, mainly in systems formed by ionic surfactants. Although very efficient, n -butyl alcohol is partially soluble in water, which would permit its passage to the effluent. In this work, isoamyl and octyl alcohols, due to their lower solubility in water, were used as cosurfactants to evaluate their influence in color removal. The colorimetry system used was the CIE L*a*b* (CIELAB) color space and CIE L*a*b* color difference (,E*ab). The wastewater used in this study was the reactive exhausted dye liquor from a dye house (first discharge) containing Procion Yellow H-E4R (CI Reactive Yellow 84), Procion Blue H-ERD (CI Reactive Blue 160) and Procion Red H-E3B (CI Reactive Red 120). The obtained results were modeled using an experimental planning (the Scheffé net) and evaluated through isoresponse diagrams by correlation graphs between experimental values and those obtained by the models with an error lower than 4%. All the optimized systems were very efficient and more than 94% of the dyes contained in the effluent were removed. The microemulsion load capacity was determined using a synthetic solution containing, the same dyes present in the reactive exhausted dyebath, but 200 times concentrated, and the dyes extraction was more than 99.6%. By comparing n -butyl, isoamyl and octyl alcohols, it was observed that the system using isoamyl alcohol presented slightly better color removal and much higher load capacity than the n -butyl and octyl alcohols. Copyright © 2004 Society of Chemical Industry [source]

Multinuclear NMR characterisation and dermal delivery of fluorinated drugs in soybean-microemulsion systems

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2009
Sonja Hoeller
Abstract The present study evaluated the effect of different commercially available soybean lecithins in microemulsion systems in terms of microstructure transformation, physicochemical properties and transport of selected entrapped fluorinated drugs through skin. Physicochemical characterisations by particle size and polydispersity index (PDI) measurements were performed and a direct correlation with NMR self-diffusion coefficients of the individual components was found. An increase of lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) in the phospholipid mixtures increased the mean particle sizes and PDI. Bicontinous microemulsion structures were proven by 1H and 31P NMR in the placebo microemulsions. Reasonable permeation of the lipophilic drugs of all microemulsions systems was confirmed in standard diffusion studies using porcine skin. This could be due to the incorporation of the drugs in the surfactant structure of the lecithin based bicontinous micro textures, as proven by 19F NMR self-diffusion studies. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2686,2695, 2009 [source]

Dramatic Enhancement of Enone Epoxidation Rates in Nonionic Microemulsions

CHEMISTRY - A EUROPEAN JOURNAL, Issue 29 2006
Thomas Wielpütz Dipl.-Chem.
Abstract The ability of microemulsions to dissolve polar and non-polar components with a huge internal interface can overcome the reagent incompatibilities frequently encountered in organic reactions. We investigated model epoxidation reactions of ,,,-unsaturated enones and alkaline hydrogen peroxide in different nonionic microemulsions, both in the presence and absence of a phase-transfer agent (PTA). The obtained reaction profiles were compared with those for the corresponding surfactant-free two-phase systems. In addition, we defined a time constant , as a measure for the rate of turnover. The epoxidation of trans -chalcone using an n -alkyl-polyoxyethylene surfactant based microemulsion was fastest in the system with the PTA (,=66 min) and slightly slower without the PTA (,=77 min). It was still slower in the two-phase system with a PTA (,=114 min) and extremely sluggish without a phase-transfer agent. With n -alkyl ,- D -glucopyranoside as the surfactant the conversion was twice as fast than in the former microemulsion systems, but the PTA did not accelerate the reaction further (,=35 and 33 min). The epoxidation of vitamin K3, the second model system, was extremely accelerated. It proceeded a factor of approximately 35 faster in the microemulsion (,=1.44 min) than in the corresponding two-phase system (,=57 min). [source]

Multinuclear NMR characterisation and dermal delivery of fluorinated drugs in soybean-microemulsion systems

JOURNAL OF PHARMACEUTICAL SCIENCES, Issue 8 2009
Sonja Hoeller
Abstract The present study evaluated the effect of different commercially available soybean lecithins in microemulsion systems in terms of microstructure transformation, physicochemical properties and transport of selected entrapped fluorinated drugs through skin. Physicochemical characterisations by particle size and polydispersity index (PDI) measurements were performed and a direct correlation with NMR self-diffusion coefficients of the individual components was found. An increase of lysophosphatidylcholine (LPC), phosphatidylethanolamine (PE) and lysophosphatidylethanolamine (LPE) in the phospholipid mixtures increased the mean particle sizes and PDI. Bicontinous microemulsion structures were proven by 1H and 31P NMR in the placebo microemulsions. Reasonable permeation of the lipophilic drugs of all microemulsions systems was confirmed in standard diffusion studies using porcine skin. This could be due to the incorporation of the drugs in the surfactant structure of the lecithin based bicontinous micro textures, as proven by 19F NMR self-diffusion studies. © 2008 Wiley-Liss, Inc. and the American Pharmacists Association J Pharm Sci 98:2686,2695, 2009 [source]