反胶束溶液萃取植物油料中蛋白质的性能研究

对AOT/异辛烷反胶束溶液萃取大豆中的蛋白质的性能进行了研究 .结果表明 :蛋白质的萃取效果取决于反胶束的w0 、水的pH值和KCl浓度 ,且蛋白质是否能进入反胶束内 ,与反胶束的大小无关 ,而主要受极性核内水的性质的影响     

Surface activity of aqueous solutions of cellulose acetate with low degree of substitution

Surface activity of aqueous solutions of cellulose acetate (CA) with total degree of substitution (〈F〉) ranging from 0.58 to 0.80 was examined. Critical micelle concentration (CMC) of the aqueous CA solutions, determined from the polymer concentration dependence of surface tension (γ), is unequivocally determined by 〈F〉, and an increase in 〈F〉 of CA brings about a lowering of the CMC. From light scattering measurements on aqueous solutions of CA with 〈F〉 = 0.8 at 20°C, it was revealed that in the vicinity of the CMC the micelles in the solution consist of c. four CA molecules, which is very close to the value obtained by analysing the data obtained from the mass action model. The surface tension of aqueous solutions of CA (〈F〉 = 0.8) in the polymer concentration range above the CMC was c. 0.74 times that of pure water over the temperature range 0–80°C.     

α-Sulfonated fatty acid esters: I. Structural effects of sodium α-sulfonated fatty acid higher alcohol esters on surface-active properties and emulsification ability

The surface-active properties and emulsification ability of sodium α-sulfonated fatty acid esters, C_mH_2m+1CH-(SO₃Na)COOC_nH_2n+1, were studied as a function of the hydrophobic alkyl chainlength in the fatty acid (m=8−16) and the alcohol (n=8−18). As a result, it was discovered that sodium α-sulfonated fatty acid esters have a structural effect on the Krafft point different from that of amphiphiles with short alkyl chains. Moreover, some of the α-sulfonated fatty acid esters have quite low interfacial tensions, as well as non-foaming properties, which depend upon the total (m+n) number of carbon atoms in the alkyl chains.     

Synthesis of mono- and diglycerides in water-in-oil microemulsions

Enzyme-catalyzed esterification was carried out in single-phase, oil-continuous microemulsions. The lipozyme was solubilized, along with glycerol and water, in the aqueous core of water/diethylhexyl sodium sulfosuccinate/hydrocarbon microemulsion system. Upon addition of fatty acid, mono- and diglycerides were formed, due to the esterification reaction taking place at the interface of the droplets in the microemulsion. The initial rate of conversion of oleic acid increases with oil chainlength of the continuous phase whereas final conversion is maximum for hexane. The conversion of stearic acid is 30% whereas conversion of oleic acid is 70%. The percent conversion of various fatty acids in the same continuous medium increases with fatty acid chainlength. The oleic acid/glycerol ratio is an important parameter for optimum conversion of oleic acid into glycerides. The yield can be increased by subsequent addition of glycerol after equilibrium is reached. High-performance liquid chromatography analysis of samples from microemulsions shows the presence of mono- and diglycerides. Possible mechanisms for the abovementioned effects are discussed.     

The effect of additives on the treatment of oil-in-water emulsions by vacuum evaporation

A simple batch vacuum evaporation process for the treatment of several oil-in-water (O/W) emulsions is reported. The experiments were carried out with waste emulsions from an industrial copper rolling process and with model emulsions prepared in the laboratory. No detailed information on the formulation of the industrial waste O/W emulsions was available. Several model emulsions were formulated using the same base oil (an 85–15% (w/w) mixture of a synthetic poly-α-olefin and a trimethylol propane trioleate ester, respectively) and one of the three following surfactants: Brij-76 (polyethylene glycol octadecyl ether, non-ionic), CTAB (hexadecyltrimethyl ammonium bromide, cationic), and Oleth-10 (glycolic acid ethoxylate oleyl ether, anionic). Experimental results show a strong influence of operating conditions, such as pressure or bath temperature, on the evaporation performance. As a general trend, the higher the values of these parameters, the higher the pollutant content in the obtained aqueous effluent. The presence of surfactants increase the evaporation rate, especially at low operating vacuum pressures, the solubility of oil molecules in water and the evaporation temperature of model O/W emulsions. Furthermore, COD reductions higher than 99.5% for the treated waste O/W emulsions were achieved.     

Synthesis and surface properties of chemodegradable anionic surfactants: Sodium carboxylates of cis-1,3-dioxane derivatives

The 2-n-alkyl-5-carboxy-5-methyl-1,3-dioxanes were obtained in good yield from the reaction of aliphatic aldehydes with 2,2-bis(hydroxymethyl)propionic acid in dichloromethane solution, catalyzed by p-toluenesulfonic acid monohydrate. Nuclear magnetic resonance analysis indicated that they were pure cis-isomers with the axial configuration of the carboxylic group at the C-5 carbon atom of the 1,3-dioxane ring. The acids were converted, with retention of the configuration, to their sodium salts by reaction with sodium methoxide or sodium hydroxide in methanol. The physicochemical properties of the acids and sodium salts, as well as their surface properties at the aqueous solution-air interface, were determined. Critical micelle concentration, surface excess concentration, surface area demand per molecule of sodium salts at the monomolecular surface layer, and standard free energy of micellization were determined based on surface tension measurements. Part XXXIV in the series: Chemical Structure and Surface Activity. Part XXXIII: A. Piasecki, A. Sokolowski, B. Burczyk, R. Gancarz, and U. Kotlewska, Synthesis, Surface Properties and Hydrolysis of Chemodegradable Anionic Surfactants: Diastereomerically Pure cis- and trans-2,5-Disubstituted-1,3-dioxanes. J. Colloid Interface Sci. 192:74–82 (1997).     

The Influence of a Phase Transition in Poly(oxyethylene)/Poly(oxypropylene)/Poly(oxyethylene) Block Copolymer Surfactants on the Properties of Material Adsorbed from Dilute Aqueous Solution

In this study the adsorption of poloxamer block copolymer surfactants to polystyrene latex has been studied at a range of temperatures. It has been noted previously that the adsorption first falls, then rises and falls again as the temperature is increased, due to the existence of a phase transition in aqueous solutions of these surfactants at specific temperatures, which may be a critical micelle temperature. The present study shows that the hydrophobicity of the surface changes in a manner related to the amount of poloxamer adsorbed (i.e. is greatly influenced by the temperature of adsorption in relation to the transition temperature). The coating layer thickness, however, is essentially unchanged by the temperature of adsorption (i.e. not related to the amount adsorbed), but is influenced by the temperature at which the sizing was undertaken. This is due to dehydration of the poly (oxyethylene) with increasing temperature. The data presented here provide a possible explanation for the changes in biological distribution of poloxamer coated particles which occur when they are injected into animals.     

COSMO‐RS Calculations of Partition Coefficients: Different Tools for Conformation Search

This work is encouraged by the growing interest and recent success of quantum mechanics‐based methods in modeling of thermodynamic properties in the field of chemical engineering and life sciences. Among those, the COSMO‐RS model has become one of the most popular methods to predict phase equilibria in complex bio‐related systems. Recently, we have shown that the quality of predictions of n‐octanol/water and micelle/water partition coefficients is improved when the weighted mixtures of conformers are used to represent molecules, thereby demanding that the conformation analysis is performed for each component of the system. In this paper, different methods for performing the conformational search are evaluated. Micelle/water partition coefficients of solutes from different homologous series in aqueous solutions of Triton X100 as well as the n‐octanol/water partitioning of three common drugs (aminopinicillanic acid, ampicillin, and penicillin G) are calculated and compared with experimental data. Conformational analysis is made by the HyperChem program for the molecules placed in vacuum as well as by using the molecular dynamics simulation in a solvent medium (n‐octanol and water). It is demonstrated that molecular dynamics simulation is a promising tool to conduct conformational analysis. Along with the possibility of providing the conformers for large surfactant and pharmaceutical molecules, the method accounts for the solvent in a realistic manner. The results for micelle/water partition coefficients illustrate that n‐octanol is a reasonable approximation for the “micelle‐like” medium in molecular dynamics (MD) simulations. Predicted n‐octanol/water partition coefficients of three penicillins are in a good agreement with literature data and values calculated by a common quantitative structure‐activity relationship (QSAR).     

Preparation of core cross-linked micelles using a photo-cross-linking agent

A new method for preparing polymeric, core cross-linked (CCL) micelles has been developed using a bifunctional photo-cross-linking agent of di(4-hydroxyl benzophenone) dodecanedioate (BPD). An amphiphilic diblock copolymer of poly(ethylene glycol)-b-poly(2-hydroxyethyl methacrylate-co-methyl methacrylate) (PEG-b-P(HEMA-co-MMA)) was synthesized via atom-transfer radical polymerization (ATRP) using a PEG macroinitiator at 85 °C. The core domains of the PEG-b-P(HEMA-co-MMA) micelles containing BPD in aqueous solution were successfully photo-cross-linked by UV irradiation for only 30 min. The HEMA units incorporated in the hydrophobic block of PEG-b-P(HEMA-co-MMA) donated labile hydrogens to excited-state BP groups in BPD, and they were subsequently cross-linked by BPD through radical-radical combination. A sufficient degree of cross-linking was obtained at an equivalent ratio of the BP groups to the HEMA units.