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1.
Qiaomei Zhu Liping Feng Masayoshi Saito 《Journal of Dispersion Science and Technology》2018,39(3):349-355
The aim of present study is to design food-grade W/O/W double emulsions encapsulating Mg2+ and investigate their stability and release properties. Prepared emulsions were characterized in terms of global stability, particle size, rheological properties, and interfacial tension. The double emulsions were sensitive to the presence of magnesium salt. The mean droplet size and viscosity of emulsions was positively correlated to MgCl2 concentration. The microscopic pictures confirmed that the water transfer between two aqueous phases caused the reduced stability of double emulsions. It was suggested that swelling breakdown was the main mechanism in controlling the release of encapsulated Mg2+. 相似文献
2.
M. E. Carlotti E. Ugazio S. Sapino E. Peira L. Battaglia R. Cavalli 《Journal of Dispersion Science and Technology》2013,34(10):1435-1444
Caffeic acid, a natural phenol with antioxidant and sunscreen activity, can undergo photooxidation upon UV irradiation. The photodegradation of caffeic acid at different concentrations was assessed in water, at pH 4.0 and 6.0, without and with TiO2. The study was then carried out on W/O/W emulsions entrapping the phenolic acid either in the inner or in the outer aqueous phase in the absence and in the presence of TiO2, added in the external phase (pH 6.0 or 7.0). The degradation of caffeic acid followed a pseudo-zero order kinetic with an inverse dependence from its initial concentration; at increasing pH of the medium caffeic acid degraded faster. The addition of TiO2 increased the initial photodegradation rate. Compared with water, W/O/W emulsions protected the phenol towards both the photodegradation and the photocatalytic activity of TiO2. Multiple systems allowed to incorporate caffeic acid and TiO2 in the same formulation avoiding any catalytic interactions. 相似文献
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4.
Fangzhi Wang Xiaoyan Zhou Jing Li Qiuyue He Ling Zheng Qing Liu Yan Chen Guizhai Zhang Xintong Liu Hongda Li 《Molecules (Basel, Switzerland)》2021,26(23)
Novel Bi2W2O9 and Bi2Mo2O9 with irregular polyhedron structure were successfully synthesized by a hydrothermal method. Compared to ordinary Bi2WO6 and Bi2MoO6, the modified structure of Bi2W2O9 and Bi2Mo2O9 were observed, which led to an enhancement of photocatalytic performance. To investigate the possible mechanism of enhancing photocatalytic efficiency, the crystal structure, morphology, elemental composition, and optical properties of Bi2WO6, Bi2MO6, Bi2W2O9, and Bi2Mo2O9 were examined. UV-Vis diffuse reflectance spectroscopy revealed the visible-light absorption ability of Bi2WO6, Bi2MO6, Bi2W2O9, and Bi2Mo2O9. Photoluminescence (PL) and photocurrent indicated that Bi2W2O9 and Bi2Mo2O9 pose an enhanced ability of photogenerated electron–hole pairs separation. Radical trapping experiments revealed that photogenerated holes and superoxide radicals were the main active species. It can be conjectured that the promoted photocatalytic performance related to the modified structure, and a possible mechanism was discussed in detail. 相似文献
5.
Majid M. Heravi Hamideh Alinejhad Fatemeh Derikvand Hossein A. Oskooie Bita Baghernejad Fatemeh F. Bamoharram 《合成通讯》2013,43(14):2033-2039
We report here two simple methods for the synthesis of benzo[c]acridine derivatives from three-component, one-pot condensation of 1-naphthylamine, dimedone, and a variety of substituted aldehydes in the presence of a catalytic amount of NH2SO3H or H6P2W18O62 · 18H2O under solvent-free conditions at 120 °C or in refluxing ethanol. 相似文献
6.
Shibin Sun Lihua Dong Zhenjiang Li Yanyan Qiu 《Journal of solid state chemistry》2011,184(8):2190-2195
A novel gas-sensing material and photocatalyst was successfully obtained by decorating Ag/AgCl nanoparticles on the W18O49 nanorods through a clean photochemical route. The as-prepared samples were characterized using combined techniques of X-ray diffractometry, electron microscopy, energy dispersive X-ray spectrometry, and X-ray photoelectron spectroscopy. Gas-sensing measurements indicate that the Ag/AgCl/W18O49 NRs sensors exhibit superior reducing gas-sensing properties to those of bare W18O49 NRs, and they are highly selective and sensitive to NH3, acetone, and H2S with short response and recovery times. The Ag/AgCl/W18O49 NRs photocatlysts also possess higher photocatalytic performance than bare W18O49 NRs for degradation of methyl orange under simulated sunlight irradiation. Possible mechanisms concerning the enhancement of gas-sensing and photocatalytic activities of the Ag/AgCl/W18O49 NRs composite were proposed. 相似文献
7.
以FT-IR方法研究了水/C12-EOx-C12•2Br/正己醇/正庚烷形成的W/O微乳中水的状态. 结果表明, 其中的水存在4种状态, 分别为阳离子头基结合水、反离子结合水、类似本体的水以及束缚在微乳栅栏层中的水. 由解卷积技术分解FT-IR谱图, 进而获得每个表面活性剂分子对应于这4种状态水分子的数目nN+, nBr-, nb和nf. 随着水含量(W0)增加, nb急剧增大, nN+少许上升, 而nf和nBr-维持不变, 这说明微乳水核逐渐长大, 且在所考察W0范围内, 表面活性剂头基解离度保持不变. 相似文献
8.
Majid M. Heravi Tandis Hosseini Fatemeh Derikvand Seyed Yahya S. Beheshtiha Fatemeh F. Bamoharram 《合成通讯》2013,43(16):2402-2406
In this work, a rapid and efficient one-pot method for the synthesis of indeno[1,2-b]quinoline-7-one derivatives by condensation of 1-naphthylamine, 1,3-indanedione, and different aldehydes in the presence of H6P2W18O62·18H2O as a green and reusable catalyst in refluxing acetic acid is described. 相似文献
9.
研究表明二元、三元钨基氧化物的红外吸收性能具有尺寸和形貌依赖性,但还没有普适性的物理学机理及计算方法。本工作基于Mie散射理论,推导了一维材料的长度与光吸收性能之间的关系,通过理论推导计算和实验验证,探究了纳米钨基氧化物的红外吸收性能与颗粒长度的关联性。首先,基于Mie散射理论的推演和计算,揭示了增加纳米Cs_(0.2)WO_3和W_(18)O_(49)材料长度可适度提高其近红外吸收性能的规律。其次,测试了合成的不同长度Cs_(0.2)WO_3纳米棒和W_(18)O_(49)纳米线的红外吸收性能,结果与理论计算及模拟相吻合。其中在2 500~20 000 nm波长范围内Cs_(0.2)WO_3纳米棒和W_(18)O_(49)纳米线随长度的变化趋势不同,Cs_(0.2)WO_3纳米棒的红外吸收性能随长度的增加而增加,而W_(18)O_(49)纳米线的红外吸收性能随长度的增加而减弱。Cs_(0.2)WO_3纳米棒和W_(18)0O_9纳米线的光热效应均随长度的增加而增加,增幅分别达18.5%和12.7%,再次验证了长度效应。 相似文献
10.
Sara Boughaba Zineb Aouf Ouahiba Bechiri Monique Mathe-Allainmat Jacques Lebreton 《Phosphorus, sulfur, and silicon and the related elements》2021,196(1):28-35
Abstract A simple, efficient and eco-friendly protocol has been described for the synthesis of α-aminophosphonates via Kabachnik-Fields reaction, catalyzed by H6P2W18O62·14H2O as a reusable catalyst. The reaction was realized by condensation of amino acids, various aromatic aldehydes and triethylphosphite under solvent-free conditions, the corresponding α-aminophosphonates were formed in good yields. All the new products were characterized by IR, 1H, 13C and 31P-NMR analyses. This method offers advantages such as simplicity workup with the green aspects, good yields and short reaction times. 相似文献
11.
Intercalation behavior of n-alkylamines into a protonated form of an A-site defective layered perovskite H2W2O7 has been investigated. Results from XRD indicate these materials are layered with the corresponding interlayer spacing governed by the n-alkylamine chain length, and a reversible intercalation and deintercalation property is observed among these intercalation compounds. The IR spectra of the intercalation compounds with n-alkylamines clearly show that n-alkyl chains possess an all-trans conformation, and H2W2O7 accommodate n-alkylamines (CnH2n+1NH2: n=3, 4, 7, 8, 12, 16) to form intercalation compounds via an acid-base mechanism. A linear relationship between the interlayer distance and the number of carbon atoms in n-alkyl chains is observed to show a bilayer arrangement of the n-alkyl chains with a tilt angle of ∼71.6°. Elemental analysis studies reveal that the amounts of intercalated n-alkylamines are about 2.0 mol per [W2O7]. Despite the surface geometry of H2W2O7 is almost identical to those of layered perovskites H2[An−1BnO3n+1], the amounts of intercalated n-alkylamines of them are different. A reasonable explanation is given through our research. 相似文献
12.
Fluorine-19 and natural abundance 17O and 183W NMR spectroscopy were employed for the characterization of aqueous solutions of (NH4)2WO2F4 and (NH4)3WO3F3. Dissolution of the (NH4)2WO2F4 complex is accompanied by its partial acid hydrolysis to give the trans(mer)-dimer, [W2O5F6]4−, and unreacted cis-[WO2F4]2−. The cis(fac)-[W2O5F6]4− anion is the major soluble product resulting from the alkaline hydrolysis of (NH4)2WO2F4 along with the isolation of the solid (NH4)2WO3F2. In addition, the edge-bridging dimer, [W2O6F4]4−, and the cyclic trimer, [W3O9F6]6−, are also suggested as hydrolysis products. Decomposition of (NH4)3WO3F3 occurs in aqueous solution to give NH4WO3F. 相似文献
13.
Three-component, one-pot synthesis of 4,6-diarylpyrimidin-2(1H)-ones and 9-phenyl-8-oxa-10,12-diaza-tricyclo[7.3.1.02,7]trideca-2(7),3,5-trien-11-one by condensing acetophenone derivatives, aldehydes, and urea in the presence of trimethylsilyl chloride using a catalytic amount of H6P2W18O62-18H2O under solvent-free conditions is reported. 相似文献
14.
Jadwiga Walczak Izabella Rychłowska-Himmel Elżbieta Mikos-Nawłatyna 《Journal of Thermal Analysis and Calorimetry》1995,43(1):201-204
Phase equilibria being established in the solid state in the system V2O5?Fe8V10W16O85 were examined by X-ray phase powder diffraction and DTA. It has been found that the system of interest is a real two-component system with an eutectic temperature 620±5°C. 相似文献
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16.
Mari Sasaki Genta Sakane Tadashi Ouchi Takashi Shibahara 《Journal of Cluster Science》1998,9(1):25-43
Sulfur/oxygen-bridged incomplete cubane-type triphenylphosphine molybdenum and tungsten-clusters [Mo3S4Cl4(H2O)2(PPh3)3]·3THF (1A), [Mo3S4Cl4(H2O)2(PPh3)3]·2THF (2A), [Mo3OS3Cl4(H2O)2(PPh3)3]·2THF (1B), and [W3S4Cl4(H2O)2(PPh3)3]·2THF (1C) were prepared from the corresponding aqua clusters and PPh3 in THF/MeOH. On recrystallization from THF, procedures with and without addition of hexane to the solution gave 1A and 2A, respectively, while the procedures gave no effect on the formation of 1B and 1C. Crystallographic results obtained are as follows: 1A: monoclinic, P21/n, a=17.141(4) Å, b=22.579(5) Å, c=19.069(4) Å, =96.18(2)°, V=7337(3) Å3, Z=4, R(R
w)=0.078(0.102); 1C: monoclinic, P2
1/c, a=12.635(1) Å, b=20.216(4) Å, c=27.815(3) Å, =96.16(1)°, V=7062(2) Å3, Z=4, R(R
w)=0.071(0.083). If the phenyl groups are ignored, the molecule [Mo3S4Cl4(H2O)2(PPh3)3] in 2A has idealized CS symmetry with the mirror plane perpendicular to the plane determined by the metal atoms, while the molecule in 1A does not have the symmetry. The tungsten compound 1C is isomorphous with the molybdenum compound 2A. 31P NMR spectra of 1A, 2A, and 1C were obtained and compared with similar clusters with dmpe (1,2-bis(dimethylphosphino)ethane) ligands. 相似文献
17.
采用水热法,在较低温度下合成了系列Bi2Mo1-xWxO6固溶体。结果表明,W的替代抑制了固溶体的晶粒生长,导致了较小的晶粒尺寸。随着x的增加,红外光谱中840cm-1处M-O键的振动频率νM-O有规律地向低频率方向移动,表明Mo6+离子逐步被W6+替代,生成了无限互溶的固溶体。光吸收性能研究表明,随着W6+逐步替代Mo6+,带隙出现了先降后升的趋势,x=0.4时带隙最小。而固溶体的光催化性能随着x的增加,出现了先增后减的趋势,x=0.4时光催化活性最高。此外,含W样品的光催化活性高于Bi2MoO6。这与固溶体的带隙、带结构和晶粒尺寸变化有关。 相似文献
18.
Zr1−xLnxW2O8−x/2 solid solutions (Ln=Eu, Er, Yb) of different substitution fractions x have been synthesized. Their X-ray diffraction (XRD) patterns have been indexed and lattice parameters calculated based on the α-ZrW2O8 structure. The coefficients of thermal expansion (CTEs) of these solid solutions were estimated to be −10.3×10−6 K−1 in temperature range of 30-100 °C. The solubility of lanthanide ions in these solid solutions decreases linearly with the increase in the radius of substituted lanthanide ions. Based on the concentration dependence of phase transition temperatures, a novel method for determination of solubility of the lanthanide ions in Zr1−xLnxW2O8−x/2 solid solutions has been developed. This method seems to be more sensitive as compared with that based on XRD technique. 相似文献
19.
TiO2,ZrO2-TiO2,andZrO2-TiO2-CeO2 were prepared by co-precipitation method and characterized by X-ray diffraction (XRD), specific surface area measurements (BET), temperature programmed desorption (NH3-TPD), oxygen storage capacity (OSC), and temperature programmed reduction (H2-TPR). The results showed that ZrO2-TiO2-CeO2 exhibited large number of surface strong acid, possessed some oxygen storage capacity, and strong redox property. The three materials were used as supports and the monolith catalysts were prepared with 1% (w) V2O5 and 9% (w)WO3 for selective catalytic reduction (SCR) of NO with ammonia in the presence of excessive O2, and the results of catalytic activity showed that the catalyst used ZrO2-TiO2-CeO2 as support yielded nearly 100% NO conversion at 275 °C at a gas hourly space velocity (GHSV) of 10000 h−1, and it had the best catalytic activity and showed great potential for practical application. 相似文献
20.
Cheng Zhang Laurence Bensaid Donna McGregor Xikui Fang Robertha C. Howell Benjamin Burton-Pye Qunhui Luo Louis Todaro Lynn C. Francesconi 《Journal of Cluster Science》2006,17(2):389-425
Lanthanide complexes of polyoxometalates, including the α2-P2W17O61
10− ligand, have been pioneered by Michael T. Pope, to whom this paper is dedicated. Examination of the solid-state and solution behavior of lanthanide complexes of the α2-P2W17O61
10− ligand are reported here to identify trends that will facilitate rational synthesis of hybrid organic lanthanide polyoxometalate complexes. Therefore, combining our data with that obtained by Pope and others a number of trends come into view. It is clear that there are two structural types for the 1:1 or 2:2 [Ln(H2O)X(α2-P2W17O61)]2
14− species. The early lanthanides show a “cap to cap” structure that allows the Ln ion to be 9 coordinate and accommodates the longer bond lengths. The mid-late lanthanides show a “cap to belt” structure that allows the lanthanides to be 8 coordinate; this structural type is appropriate for the shorter bond lengths of the later lanthanides. The 1:1⇌1:2 equilibrium, that was observed by Pope for the Ce(III) analog is prevalent for the early- mid lanthanides. This equilibrium is slightly dependent on pH; however, cations have a major influence on this equilibrium. Larger, poorly hydrated cations appear to favor the 1:2 species for the early to mid lanthanides. Cations do not appear to influence the equilibrium for the later lanthanides; for all counterions, the 1:1 species was stable with no trace of the 1:2 species. Stability constants, K1 and K2, for the early to mid lanthanides were measured in this study by a competitive method and compared well with other published stability constant determinations. We suggest that the stability constants are not only dependent on the strength of interaction of the Ln with the α2-P2W17O61
10− ligand, but are also significantly influenced by the medium. The medium may bias the equilibria of the early-mid lanthanides and later lanthanides. The log K1/log K2 ratios are very close, suggesting that it is difficult to separate the 1:1 and 1:2 Ln: α2-P2W17O61
10− species.Electronic Supplementary Material Supplementary material for this article is available at and is accessible for authorized users.This paper is dedicated to Professor Michael T. Pope in honor of his substantial and sustained contributions to polyoxometalate chemistry and his inspiration to scientists working in the field. 相似文献