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1.
The aqueous mixed system sodium dehydrocholate (NaDHC)–sodium oleate (NaOL) was studied by several methods to determine the influence of the hydrophobic structure of both surfactants in the mixed micellization and the formation of the mixed monolayer adsorbed at the air–water interface. The molecular area at the critical micelle concentration in pure surfactant solutions suggests that the adsorbed oleate chain was folded to allow the double bond in the middle of the molecule to remain in contact with water, and that the NaDHC molecule was situated with its plane laying parallel to the water surface, allowing the three carbonyl groups in the hydrocarbon backbone to form hydrogen bonds with water. The interaction was repulsive at the surface, and in the mixed monolayer some molecules must move away the less hydrophilic groups from water (double bond of NaOL, carbonyl groups of NaDHC). The interaction in mixed micelles was strongly attractive, showing a preferential composition roughly equimolar. The hydrolysis in mixed micelles was augmented in comparison with pure surfactants systems, which could be explained by assuming the existence of a more hydrophobic mixed micelle core. The mixed micelle degree of ionization was below that of the pure micelles, thus indicating a high surface charge density. 相似文献
2.
Maria B. Sierra José L. Rodríguez Rosanna M. Minardi Marcela A. Morini Emilio Aicart Elena Junquera Pablo C. Schulz 《Colloid and polymer science》2010,288(6):631-641
Sodium oleate (NaOL, C18H33O2Na)–sodium linoleate (NaLin, C18H31O2Na) mixtures were studied in the micellar and in the air/water interface states at 298.15 K. Three aggregation steps were
found: a premicellar aggregation, the critical micelle concentration (CMC), and a structural change of micelles. Micelles,
both at the CMC and at the structural change concentration, are richer in oleate than the overall mixture composition. Micelles
are strongly non-ideal and the interaction is repulsive. The non-ideal behavior and the dependence of the micelle ionization
degree with micelle composition are explained on the basis of the interaction of the π electrons of the surfactants’ chains with water at the hydrocarbon/water micellar interface. The air/solution adsorbed monolayer
is also non-ideal, but the interaction is attractive and there is a preferential composition with a mole fraction of sodium
oleate of about 0.7. The surface pseudophase behaves as if oleate were the solvent and linoleate a strongly soluble solute.
This behavior and the dependence of the average area per adsorbed molecule were explained on the basis of the interaction
of the double bonds with water. At the air/solution interface, the linoleate molecule area was similar to that of a heterogemini
surfactant having a spacer with seven carbon atoms. 相似文献
3.
Single and mixed micelle formation by sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) and their mixtures in pure water and in the presence of water-soluble polymers such as Synperonic 85 (triblock polymer, TBP), hydroxypropylcellulose (HPC), and carboxymethylcellulose sodium salt (CMC) were studied with the help of conductivity, pyrene fluorescence, cyclic voltammetry, and viscosity measurements. Conductivity measurements showed a single aggregation process for pure surfactants and their mixtures both in pure water as well as in the presence of water-soluble polymers. Triple breaks corresponding to two aggregation processes for SDS, SDBS, and their mixture in the presence of TBP were observed from fluorescence measurements. The first one demonstrated the critical aggregation process due to the adsorption of surfactant monomers on TBP macromolecule. The second one was attributed to the participation of surfactant–polymer aggregates formed at the first one, in the micelle formation process. The aggregation number ( N agg) of single and mixed micelles and diffusion coefficient ( D) of electroactive probe were computed from the fluorescence and cyclic voltammetry measurements, respectively. Both parameters, along with the viscosity results, indicated stronger SDS–polymer interactions in comparison to SDBS–polymer interactions. Mixed surfactant–polymer interactions showed compensating effects of both pure surfactants. The nature of mixed micelles was found to be ideal in all cases, as evaluated by applying the regular solution and Motomura's approximations. 相似文献
4.
HUANG Wei-Yuan LIU Jin-TaoShanghai Institute of Organic Chemistry Chinese Academy of Sciences Lingling Lu Shanghai ChinaXIE Yin-Bao HE Xian-QiChengdu University of Science Technology Chengdu Sichun China 《中国化学》1994,12(6):528-533
Hydrodehalogenation or hydrosulfonate-dehalogenation products, hydrohalofluoro-carbons or 2-hydropolyhalofluoroalkanesulfonates, were formed respectively from the title reaction under mild condition in good yield. 相似文献
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《Journal of Inorganic and Nuclear Chemistry》1976,28(3):427-429
Mössbauer spectra were obtained for hydrated and dehydrated sodium nitroprusside absorbers at room and lower temperatures. Some of the absorbers were heated at temperatures between 82 and 186°C for various lengths of time before the spectra were taken. The largest changes in the isomer shift and quadrupole splitting were noted after the absorbers had been heated to temperatures above 100°C. 相似文献
7.
The hexagonal liquid crystalline phase of SDS (Sodium dode-cyl sulfate)/H2O system changes into lamellar liquid crystal and the effective length of surfactant molecule d0/2 in the lamellar liquid crystal decreases with the addition of ethanol. The micellar aggregation number N of SDS decreases and the micellar diffusion coefficient increases with the added ethanol. Under a constant concentration of SDS, the molecule number ratio of ethanol to SDS in the micelle increases with the concentration of ethanol and even exceeds 10 when ethanol concentration is 1. 085 mol/L. All these results show that ethanol, even though a short chain alcohol and soluble in water, can partly exist in the interphase of the amphiphilic aggregates showing some properties of co-surfactant. 相似文献
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V. P. Yuryev A. L. Blumenfeld E. E. Braudo V. B. Tolstoguzov 《Colloid and polymer science》1991,269(8):850-854
Summary NMR and potentiometric methods revealed at least two types of interactions of Na+ and K+ ions with -carrageenan, viz., Coulombic interaction with polysaccharide sulfate groups, and a coordination one, leading, in the case of the Na+ ions, to formation of nonstoichiometric complexes. The absence of any correlation between the coordination binding density of the cations and their promoting effect on gelation process was demonstrated. 相似文献
12.
V. I. Saldin V. V. Sukhovey N. N. Savchenko A. B. Slobodyuk L. N. Ignatieva 《Russian Journal of Inorganic Chemistry》2016,61(5):630-637
The results of DSC studies of NaBH4–KBF4 mixtures are presented. It is shown by chemical analysis, XRD analysis, IR spectroscopy, and 11B and 9F MAS NMR that the decomposition of the mixtures starts at ~563 K to yield polyhedral borohydride compounds (predominantly B12H122-) in the solid residue. This temperature is much lower than the decomposition temperature of pure NaBH4 (749 K). The mechanism of formation of the B12H122- anion has been proposed and confirmed. According to this mechanism, boron atoms from KBF4 are involved in the formation of this anion. 相似文献
13.
《Journal of solid state chemistry》1986,65(2):199-204
Powder NaAl5O8 doped with Fe3+ emits two broadbands at 705 and 758 nm. The shape of the combined emission depends on the annealing time of the samples and it is affected by the temperature of the samples, even below room temperature. It is concluded that these features are due to the occupation of at least two crystallographic inequivalent sites by the Fe ions in the sodium β″-aluminate: the BR sites (I) in the conduction region and Al(3) sites (II) of the spinel blocks near to the conduction plane. It is proposed that iron diffusion from I sites to vacant II sites should also occur in the temperature range below room temperature after the samples are submitted to long annealing times at synthesis temperature. 相似文献
14.
V. I. Saldin V. V. Sukhovei N. N. Savchenko A. B. Slobodyuk V. Ya. Kavun 《Russian Journal of Inorganic Chemistry》2017,62(4):489-497
The KBH4?NaBF4 mixture was studied by thermal analysis (differential scanning calorimetry). Chemical analysis, X-ray powder diffraction analysis, IR spectroscopy, and 11B and 19F MAS NMR spectroscopy showed that the primary stage of the complex pyrolysis process is a metathesis reaction between components to form a new mixture, NaBH4?KBF4, the decomposition of which with the release of gaseous products and the formation of polyhedral borohydride compounds (mainly B12H12 2-) in the solid residue begins at a temperature of about 563 K. At a certain ratio between reactants in the initial mixture KBH4?NaBF4, the B12H12 2- anion can form with the material participation of the BF4 - anion. 相似文献
15.
HUANG Wei-Yuan WU Fan-Hong HUANG Bing-NanShanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai China 《中国化学》1994,12(6):549-551
Polyfluoroalkyl iodides, such as Cl(CF2)nI(n=4, 6, 8, 1b-1d) and F(CF2)nI (n=6, 8,1e-1f) reacted with sodium sulfite in neutral aqueous DMF solution to give the corresponding sulfinates Cl(CF2)nSO2Na (n=4, 6, 8, 2b-2d) and F(CF2)nSO2Na (n=6, 8, 2e-2f) in moderate yields. I(CF2)2O(CF2)2SO2F ( la ) reacted under the same condition to give 3-oxa-octafluoropentane-1,5-disulfinates (2a). 相似文献
16.
The susceptibility of heart healthy ω-3 fatty acids to lipid oxidation has hindered its incorporation into healthful foods and beverages. In this study, plant-based flaxseed oil rich in ω-3 fatty acids were dispersed into primary, secondary and tertiary emulsion system. A primary emulsion containing sodium caseinate-stabilized cationic droplets was prepared by homogenizing flaxseed oil as oil phase and sodium caseinate solution as the aqueous phase in an ultrasonicator. A secondary emulsion comprising of sodium caseinate–sodium alginate anionic droplets were produced by diluting appropriate primary emulsion with alginate solution. Further, a tertiary emulsion composed of sodium caseinate–sodium alginate–chitosan-coated cationic droplets was produced by diluting secondary emulsion with chitosan solution. The resistance of primary, secondary and tertiary emulsions with the same lipid concentration to destabilization by thermal treatment (30–90 °C for 30 min), sodium chloride addition (≤70 mM NaCl) and oxidative degradation (hydroperoxide concentration and TBARS) was determined. The results showed that secondary emulsions could resist variation in environmental stresses of salt and heat as well as protect the oil phase from decomposition better than primary and tertiary emulsions. Interfacial engineering could be used to design emulsion system with desirable characteristics. 相似文献
17.
The oxidizing mechanism of podophyllotoxin and its derivatives by sodium persulfate has been studied by laser flash photolysis and pulse radiolysis. The formation and decay processes of transient species of podophyllotoxin and its derivatives have been observed, and a series of rate constants for the formation and decay of transient species have been determined. It has been found that there is a light (UV) sensitive group on the C-4 of podophyllotoxin and two light (UV) sensitive groups on the C-4 and C-4' of 4'-demethylepipodophyllotoxin. 相似文献
18.
《Journal of Coordination Chemistry》2012,65(23):4177-4184
Coordination polymers [Na(Hidc)(H2idc)(H2O)2] (1) and [Na(Hidc)(H2O)] (2) (H2idc?=?imidazole-4,5-dicarboxylic acid) have been synthesized hydrothermally and analyzed by single-crystal X-ray diffraction analysis, TGA, and IR. Compound 1 displays a 1-D coordination network and 2 exhibits a layered coordination structure. Both compounds form 3-D frameworks through hydrogen bonds. 相似文献
19.
《Fluid Phase Equilibria》1999,157(2):229-255
Phase equilibria in the NaCl–Na2SO4–H2O system were investigated at 200 and 250 bar for total salt concentrations ranging from 5 to 20 wt.% total salt over temperatures ranging from 320 to 400°C. In addition to providing data for this ternary system, the experiments also added information on the phase behavior of the two binary systems: NaCl–H2O and Na2SO4–H2O. For salt mixture compositions which were rich in sodium sulfate, a solid phase was observed to nucleate from the homogeneous liquid phase. Salt mixture compositions which had a high fraction of sodium chloride exhibited a vapor separation from a homogeneous liquid phase. By fitting curves to the solid–liquid and vapor–liquid separation temperatures, the temperature and composition of a constrained invariant point where liquid, solid salt and vapor are in equilibrium were estimated. These estimates were performed at discrete compositions of 5, 10, 15 and 20 wt.% total salt at pressures of 200 and 250 bar. The temperature and composition of the invariant point increased with increasing pressure following a simple thermodynamic model for boiling point elevation in a nearly ideal solution. 相似文献
20.
Jie Feng Shaohua Luo Kexing Cai Shengxue Yan Qing Wang Yahui Zhang Xin Liu 《中国化学快报》2022,33(5):2316-2326
Among the large energy storage batteries, the sodium ion batteries(SIBs) are attracted huge interest due to the fact of its abundant raw materials and low cost, and has become the most promising secondary battery. Tunnel-type sodium manganese oxides(TMOs) are industrialized cathode materials because of their simple synthesis method and proficient electrochemical performance. Na0.44MnO2(NMO) is considered the best candidate material for all tunnel-type structural materials. ... 相似文献