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Cheng N.,Shandong University | Yu P.,China Research Institute of Daily Chemical Industry | Wang T.,China Institute of Technology | Sheng X.,Shandong University | And 3 more authors.
Journal of Physical Chemistry B | Year: 2014

Halogen-free and low-cost alkylcarboxylate-based anionic surface active ionic liquids (SAILs), namely, 1-butyl-3-methylimidazolium alkylcarboxylates ([C4mim][CnH2n-1O2], n = 8, 10, 12), were first synthesized through the neutralization of imidazolium hydroxide by alkylcarboxylic acids. A systematic study of their self-aggregation behavior in water was investigated by surface tension, electrical conductivity, steady-state fluorescence quenching, and 1H NMR. The micellar properties of this series of SAILs in ethylammonium nitrate (EAN) were also studied by surface tensiometry for comparison. A set of surface active parameters and thermodynamic parameters of these compounds in water and EAN was obtained. Surface tension results show that the surface activity of [C4mim][CnH 2n-1O2] in EAN is inferior to that in water. They exhibit a higher ability to aggregate in water than the traditional anionic surfactants, sodium alkylcarboxylates (SAC), and anionic SAILs, 1-butyl-3-methylimidazolium alkylsulfates ([C4mim][CnH2n+1SO4]) with the same hydrocarbon chain length. This demonstrates that the incorporation of carboxylate group and [C4mim]+ cation favors micelle formation. To understand the discrepancy in the surface activity of alkylsulfate- and alkylcarboxylate-based SAILs, theoretical calculations were performed to give electrostatic potential of the corresponding anions. The higher surface activity of [C4mim][C12H23O 2] mainly originates from the lower electronegativity of its anion. Density functional theory (DFT) calculations manifest that the interaction energy of binary combination SAILs-EAN is larger than that of SAILs-H 2O, implying the stronger interaction of the former. Consequently, it is more difficult for [C4mim][CnH2n-1O 2] to self-aggregate in EAN than in H2O. This work is expected to be of practical value for the environmentally friendly alkylcarboxylate-based SAILs in some potential applications, including nanomaterials synthesis and phase separation, among others. © 2014 American Chemical Society. Source

Sun X.,Shandong University | Sun X.,China Research Institute of Daily Chemical Industry | Xin X.,Shandong University | Tang N.,Shandong University | And 3 more authors.
Journal of Physical Chemistry B | Year: 2014

Supramolecular hydrogels were prepared in the mixtures of biological surfactant sodium deoxycholate (NaDC) and halide salts (NaCl and NaBr) in sodium phosphate buffer. It is very interesting that with the addition of two kinds of amino acids (l-lysine and l-arginine) to NaDC/NaX hydrogels, the gel becomes solution at room temperature. We characterized this performance through phase behavior observation, transmission electron microscopy, scanning electron microscopy, X-ray powder diffraction, Fourier transform infrared spectra, and rheological measurements. The results demonstrate that the gels are formed by intertwined fibrils, which are induced by enormous cycles of NaDC molecules driven by comprehensive noncovalent interactions, especially the hydrogen bonds. Our conclusion is that the presence of halide salts (NaCl and NaBr) enhances the formation of the gels, while the addition of amino acids (l-lysine and l-arginine) could make the breakage of the hydrogen bonds and weaken the formation of the gels. Moreover, its fast disassembly in the presence of amino acids allows for the release of substances (i.e., the dye methylene blue) entrapped within the gel network. The tunable gel morphology, microstructure, mechanical strength, and anisotropy verify the role of halide salts and amino acids in altering the properties of the gels, which can probably be exploited for a variety of applications in future. © 2014 American Chemical Society. Source

Li Y.,China Research Institute of Daily Chemical Industry
Shiyou Huagong/Petrochemical Technology | Year: 2015

2-Hexyl-1-decanol(2HD) was synthesized from 1-octanol through the Guerbet reaction over CuO-NiO as dehydrogenating-hydrogenating catalyst and KOH as base catalyst. The effects of catalyst supports, CuO-NiO loading and n(CuO):n(NiO) on the synthesis were investigated. The effect of the addition of a third metallic oxide to the CuO-NiO catalyst on the reaction was also studied. All the catalysts were characterized by means of TEM, XRD and BET. The addition of ZnO or MgO as the third component could improve the 1-octanol conversion but reduce the 2HD yield. The CuO-NiO catalyst with the highest activity could be prepared under the conditions of CaCO3 as support, CuO-NiO loading 30%(w) and n(CuO):n(NiO) 1:2. Under the optimized reaction conditions of 230℃, 1 h and using the above CuO-NiO catalyst in the presence of KOH, the 1-octanol conversion and 2HD yield reached 84.8% and 73.0%, respectively. The characterization results showed that there was a synergistic effect between CuO and NiO in the CuO-NiO catalysts. ©, 2015, Beijing Research Institute of Chemical Industry. All right reserved. Source

Wang R.,China Research Institute of Daily Chemical Industry | Li Y.,China Research Institute of Daily Chemical Industry
Journal of Chemical and Engineering Data | Year: 2013

The micellar and interfacial behavior of mixed systems of dodecyldiethoxylamine oxide/sodium dodecylsulfate (DDEAO/SDS) and dodecyldiethoxylamine oxide/dodecyltrimethylammonium chloride (DDEAO/DTAC) at various molar ratios were investigated by means of surface tension measurement. The various physicochemical properties such as surface activity parameters, the composition of mixed micelles, interactions between molecules and thermodynamic parameters have been evaluated. On the basis of several theories, such as regular solution theory, the ideal mixing model and Rosen's approaches, the results have been explained and compared. In DDEAO/DTAC mixed systems, the results display slight deviation from ideal behavior. However, there is a large negative deviation in DDEAO/SDS mixed systems. From the results of βm and βσ values, DDEAO/SDS mixed systems exhibit a stronger interaction and a greater synergism compared with the DDEAO/DTAC mixed systems. The negative values of ΔGads0 and ΔGm0 suggest that the adsorption at the mixed monolayer is preferable and the micelle formation is a spontaneous process, respectively. © 2013 American Chemical Society. Source

Wang G.,China Research Institute of Daily Chemical Industry | Qu W.,Shanxi Datong University | Du Z.,China Research Institute of Daily Chemical Industry | Du Z.,Shanxi University | And 2 more authors.
Journal of Physical Chemistry B | Year: 2013

Adsorption and aggregation behaviors of novel tetrasiloxane-tailed gemini surfactants N,N′-ditetrasiloxane-N,N′-digluconamide oligo ethylene glycol diglycidyl (Si-m-Si, where m is the number of ethylene glycol of 1, 2, and 3) were investigasted using surface tension, bromophenol blue encapsulation, dynamic light scattering (DLS), and transmission electron microscope (TEM) methods. The static surface tension of the aqueous Si-m-Si solutions measured at the critical aggregate concentration (CAC) was observed to be lower than that of traditional hydrocarbon gemini surfactants. This suggests that these newly synthesized gemini surfactants are capable of forming a closely packed monolayer film at the air/aqueous solution interface. With a combination of DLS data, TEM measurements, and bromophenol blue entrapment studies, formations of vesicles in Si-m-Si solutions appear to occur at a concentration well above the CAC. Moreover, the size of vesicles depended on their m values. © 2013 American Chemical Society. Source

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