CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Yang Li,Chunyan Ma,Hongling Yang,Zhongshen Zhang,Xin Zhang,Nanli Qiao,Junhui Wang,Zhengping Hao
The traditional reaction temperatures of 1-butene isomerization to 2-butene tend to above 100 °C, while here we report the unique catalytic performance of a Pd loaded silica nanospheres catalyst for 1-butene double-bond-shift isomerization at room temperature and showed 2-butene yield of 37.0%. Furthermore, the introduction of O 2 into the reaction mixture dramatically improved the yield efficiency to 57.2% without the formation of by-product CO 2 . The reaction process is proved that the ratio of trans -2-butene to cis -2-butene in the final product was determined by the trans : cis ratio of the butenylcarbenium ion intermediate, and the ratio of trans -2-butene to cis -2-butene decreased with the increasing reaction temperature. Unlike other palladium catalyst systems, Pd 0 nanoparticles were proved to act as catalytic active sites, and their oxidation and aggregation resulted in a decrease in activity. Most importantly, the catalyst acidity affected the catalytic performance, which provides theoretical basis for the choice of catalysts.
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
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2017
·
IF 2.323
Kai Zhang,Xianbao Cui,Tianyang Feng,Ying Zhang,Haofei Liu
Solubilities of diethyl phthalate (DEP), dicyclopentadiene (DCPD), and styrene in ionic liquid 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]) were measured in the temperature range T = (283.15–353.15) K and at atmospheric pressure (101.3 kPa) the corresponding temperature–composition phase diagrams were obtained. Solubilities of DEP and DCPD in [Emim][OAc] increase with temperature but the solubility of styrene in [Emim][OAc] decreases with temperature. The ternary liquid–liquid equilibrium data for the system of styrene + glycerol + [Emim][OAc] were also determined at temperatures of 298.15, 308.15, 318.15, and 328.15 K, and the results indicate that the addition of glycerol can significantly reduce the solubility of styrene in [Emim][OAc]. For the ternary system, when the amount of glycerol is enough, the solubility of styrene in [Emim][OAc] increases with temperature. The experimental data were correlated by the nonrandom two-liquid activity coefficient model and the binary interaction parameters were obtained.
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PLoS One
·
2017
·Vol. 12
·期 5
·e0178213
·
IF 2.806
Yangyang Wang,Fangfang Li,Xinling Ruan,Jian Song,Lv Lv,Liyuan Chai,Zhihui Yang,Lin Luo
A stable bacterial consortium (LV-1) capable of degrading di- n -butyl phthalate (DBP) was enriched from river sludge. Community analysis revealed that the main families of LV-1 are Brucellaceae (62.78%) and Sinobacteraceae (14.83%), and the main genera of LV-1 are Brucella spp. (62.78%) and Sinobacter spp. (14.83%). The optimal pH and temperature for LV-1 to degrade DBP were pH 6.0 and 30°C, respectively. Inoculum size influenced the degradation ratio when the incubation time was < 24 h. The initial concentration of DBP also influenced the degradation rates of DBP by LV-1, and the degradation rates ranged from 69.0–775.0 mg/l/d in the first 24 h. Degradation of DBP was best fitted by first-order kinetics when the initial concentration was < 300 mg/l. In addition, Cd 2+ , Cr 6+ , and Zn 2+ inhibited DBP degradation by LV-1 at all considered concentrations, but low concentrations of Pb 2+ , Cu 2+ , and Mn 2+ enhanced DBP degradation. The main intermediates (mono-ethyl phthalate [MEP], mono-butyl phthalate [MBP], and phthalic acid [PA]) were identified in the DBP degradation process, thus a new biochemical pathway of DBP degradation is proposed. Furthermore, LV-1 also degraded other phthalates with shorter ester chains (DMP, DEP, and PA).
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AUSTRALIAN JOURNAL OF CHEMISTRY
·
2016
·Vol. 69
·期 11
·1254-1260
·
IF 1.427
Jiequn Wu,Tianxiang Yin,Shaoxiong Shi,Weiguo Shen
The systematic investigation of the aggregation behaviours of newly synthesised surface-active ionic liquids 1-alkyl-3-methylimidazolium bis(2-ethylhexyl)sulfosuccinate ([Cnmim][AOT], n = 2, 3, 5, 6, 7) by various techniques is reported. The critical aggregation concentrations (CACs) and the standard Gibbs free energies of aggregation () were determined from measurements on conductivity, fluorescence, and surface tension, which suggested a stronger self-assembly ability in the bulk solution for [Cnmim][AOT] surfactants with longer alkyl chain cations. An interesting structure transition driven by the penetration of the imidazolium cation into the aggregate when n > 4 was found by analysis of the variations of the values of CAC, , the degree of counter ion binding (β), and the micropolarity (I1/I3) immediately after the CAC with changing alkyl chain length of the imidazolium cation, which was further confirmed by 1H NMR measurements.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
·
IF 2.76
Zhang Junjie,Jing Wang,Shuping Xu,Weiqing Xu
Metal-organic charge transfer complexes, MTCNQ (M = Ag or Cu; while, TCNQ = 7,7,8, 8-tetracyanoquinodimethane), have received great attentions for their electrical and optical properties. To prepare AgTCNQ, poly(ethylene glycol)-blockpoly(propylene glycol)-block-poly(ethylene glycol) (P123) has been applied as a soft template for the growth of AgTCNQ. This triblock copolymer is the structure directing agent and necessary to the formation of the AgTCNQ nanostructure. By tuning the concentration of P123, we achieved two novel AgTCNQ nanocrystals (nanospindle and nanocones) for the first time via a one-pot reaction in aqueous solution. In addition, sodium citrate acts as a reductant and ensures the proceeding of the reaction between Ag + and TCNQ particles. A ligand-limited facet growth mechanism has been proposed to explain the shape regulation of AgTCNQ through the facet block effect by P123. This soft template method also enlightens us in the synthesis of other organic crystals with different shapes.
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BIODEGRADATION
·
2016
·Vol. 27
·期 1
·37-46
·
IF 2.208
Zhou YuYang,Huang Huanlin,Shen Dongsheng
This study evaluated substrate interactions during the aerobic biodegradation of 1, 4-dioxane and BTEX mixtures by a pure culture, Acinetobacter baumannii DD1, which is capable of utilizing 1, 4-dioxane for growth. A. baumannii DD1 could utilize BTEX as a sole carbon source, but could not utilize m -xylene and p -xylene. In binary mixtures, there was a lag of about 14 h before the degradation of BTE, and 1, 4-dioxane only started to be utilized when BTE was completely degraded by 1, 4-dioxane-grown DD1. Furthermore, the biodegradation rate of 1, 4-dioxane decreased from 73.33 to 40.74 mg/(h g dry weight) after the biodegradation of benzene. 1, 4-dioxane could not be degraded after the biodegradation of o -xylene in 80 h. DD1 could also not degrade m -xylene and p -xylene coexisting with 1, 4-dioxane. The ability of DD1 to degrade BTEX occurred in the following order: benzene > ethylbenzene > toluene > o -xylene > m -xylene = p -xylene. The biodegradation of 1, 4-dioxane was not activated in the mixture with o -xylene, primarily because of the accumulation of the specific toxic intermediate, 2, 3-dimethylphenol. The lag in BTE degradation was presumably because of the induction of enzymes necessary for BTE degradation. Additionally, SDS-PAGE analysis demonstrated that there were different proteins during the degradation of benzene and 1, 4-dioxane.
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APPLIED SURFACE SCIENCE
·
2016
·
IF 3.15
Ding Wang,Minglu Zhang,Huaijuan Zhuang,Xu Chen,Xianying Wang,Xuejun Zheng,Junhe Yang
(GaN) 1-x (ZnO) x composite nanofibers with hollow structure were prepared by initial electrospinning, and the subsequent calcination and nitridation. The structure and morphology characteristics of samples were investigated by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS) and transmission electron microscopy (TEM). The characterization results showed the phase transition from ZnGa 2 O 4 to (GaN) 1-x (ZnO) x solid-solution under ammonia atmosphere. The preparation conditions were explored and the optimum nitridation temperature and holding time are 750 °C and 2 h, respectively. The photocatalytic properties of (GaN) 1-x (ZnO) x with different Ga:Zn atomic ratios were investigated by degrading Rhodamine B under the visible light irradiation. The photocatalytic activity sequence is (GaN) 1−x (ZnO) x (Ga:Zn = 1:2) > (GaN) 1−x (ZnO) x (Ga:Zn = 1:3) > ZnO nanofibers > (GaN) 1−x (ZnO) x (Ga:Zn = 1:4) > (GaN) 1−x (ZnO) x (Ga:Zn = 1:1). The photocatalytic mechanism of the (GaN) 1−x (ZnO) x hollow nanofibers was further studied by UV–vis diffuse reflectance spectra. The excellent photocatalytic performance of (GaN) 1−x (ZnO) x hollow nanofibers was attributed to the narrow band gap and high surface area of porous nanofibers with hollow structure.
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Molecular Catalysis
·
2017
·
IF 0
Jin Liu,Wei Lu,Qian Zhong,Xiaodan Jin,Lanyue Wei,Hongzhang Wu,Xinlei Zhang,Lili Li,Zhenling Wang
Single-crystal Bi 2 Ga 4 O 9 nanoplates with exposed {110} facets have been synthesized without any organic facet-controlling agents. The nanostructures and the formation process mechanism of the obtained Bi 2 Ga 4 O 9 nanoplates are investigated using XRD, TEM and SEM. UV–vis DRS and VB-XPS analyses demonstrate that the CB position of Bi 2 Ga 4 O 9 nanoplates is shifted up by 0.21 eV compared with that of Bi 2 Ga 4 O 9 particles. PL spectra and photoelectrochemical texts show that the separation efficiency of photogenerated electron-hole pairs of Bi 2 Ga 4 O 9 nanoplates is higher than that of Bi 2 Ga 4 O 9 particles. The enhanced photocatalytic activity of Bi 2 Ga 4 O 9 nanoplates is mainly ascribed to the exposed {110} facets. PL technique and radical trapping experiments demonstrate that h + , OH and O 2 − are responsible for the degradation of Acid Red 1 (AR1) over Bi 2 Ga 4 O 9 nanoplates.
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JOURNAL OF APPLIED ELECTROCHEMISTRY
·
2016
·Vol. 46
·期 11
·1147-1155
·
IF 2.223
Jin Biyao,Zhang Yanyu,Zhao Lianhua
Abstract PdAu 3:1/C-1 and PdAu 3:1/C-2 nanoparticles were prepared in methylene chloride and water, respectively. The syntheses featured the use of tetrabutylammonium hydroxide as a phase-transfer agent and stabilizer. Electrochemical characterization showed that compared with PdAu 3:1/C-2, PdAu 3:1/C-1 had superior ethanol oxidation reaction (EOR) activity in alkaline media. The results of X-ray powder diffraction indicated that PdAu 3:1/C-1 was an alloy, whereas PdAu 3:1/C-2 was a heterogeneous mixture of the two metals. Moreover, transmission electron microscope analyses revealed that the PdAu 3:1/C-1 nanoparticles dispersed homogeneously on the carbon carrier without evident aggregation. Further, the X-ray photoelectron spectroscopy results demonstrated that the hydroxyl content was higher on the surface of PdAu 3:1/C-1 than that of PdAu 3:1/C-2. The increase of adsorptive hydroxyl on the surface of PdAu 3:1/C-1 could facilitate the adsorption and oxidation of CO on the catalyst surface, thus improving EOR activity and catalyst stability. Graphical Abstract
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Particuology
·
2017
·
IF 2.621
Rongjie Ling,Wu Chen,Jin Hou
Modified nanosized MFI (ZSM-5 and silicalite-1) zeolites were successfully synthesized by a hydrothermal method using aluminum isopropoxide and tetraethylorthosilicate as the raw materials. The synthetic zeolites were characterized by X-ray diffraction, energy dispersion spectroscopy, and scanning electron microscopy. The ZSM-5 and silicalite-1 zeolites exhibited ellipse-like and cubic columns, respectively. The K + ion-exchange equilibrium and ion-exchange capacity of the synthetic zeolites in seawater were investigated. The K + ion-exchange of synthetic zeolites was rapid and reached an ion-exchange balance in approximately 20 min. The K + ion-exchange capacity of ZSM-5 and silicalite-1 in seawater was 56.7 and 48.7 mg/g, respectively. The synthetic zeolites have high selectivity toward K + , and therefore, they can be used to selectively extract potassium from seawater.
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TALANTA
·
2016
·
IF 4.035
Yuling Chen,Zilin Chen
Novel covalent organic framework-1 modified magnetic nanoparticles (M-COF-1) were prepared for extraction of paclitaxel from rat plasma samples. Paclitaxel is an important anti-cancer drug in clinical chemotherapy. COF-1 was immobilized on the surface of magnetic nanoparticles by bio-inspired polydopamine functionalization method because polydopamine can supply catechol groups for supporting the immobilization of COF-1. The formation of M-COF-1 has been confirmed by Fourier transform infrared spectroscopy and transmission electron microscopy . A M-COF-1-based extraction method was developed for selective extraction of paclitaxel in aqueous solutions. Extraction conditions were investigated, including sample pH value, acetonitrile content, extraction time and sample volume. By combining with HPLC, this method showed a good linear range of 0.1–200 ng/mL with a low limit of detection of 0.02 ng/mL. The method was also applied for the pretreatment of paclitaxel in rat plasma samples, which showed effective enrichment efficiency and good clean-up capacity. Recoveries were calculated to be 99.4–103.7% with relative standard deviations less than 2.3%.
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BIOCONJUGATE CHEMISTRY
·
2015
·
IF 4.513
De-Hong Yu,Ya-Rong Liu,Xin Luan,Hai-Jun Liu,Yun-Ge Gao,Hao Wu,Chao Fang,Hong-Zhuan Chen
Multidrug resistance is the main cause of clinical chemotherapeutic failure. Antiangiogenic cancer therapy with nanomedicine that allows the targeted delivery of antiangiogenic agents to tumor endothelial cells may contribute to innovative strategies for treating multidrug-resistant cancers. In this study, we developed a new nanodrug delivery system (nano-DDS), with improved antiangiogenic efficacy against multidrug resistant human breast cancer MCF-7/ADR cells. Here, the IF7 ligand was a peptide designed to bind the annexin 1 (Anxa 1), a highly specific marker of the tumor vasculature surface, with high affinity and specificity. IF7-conjugated Anxa 1-targeting nanoparticles containing paclitaxel (IF7-PTX-NP) allowed controlled drug release and displayed favorable prolonged circulation in vivo. IF7-PTX-NP was significantly internalized by human umbilical vein endothelial cells (HUVEC) through the IF7-Anxa 1 interaction, and this facilitated uptake enhanced the expected antiangiogenic activity of inhibiting HUVEC proliferation, migration, and tube formation in a Matrigel plug relative to those of Taxol and PTX-NP. As IF7-PTX-NP targeted the tumor vessels, more nanoparticles accumulated in MCF-7/ADR tumors, and more importantly, induced significant apoptosis of the tumor vascular endothelial cells and necrosis of the tumor tissues. Low dose paclitaxel (1 mg/kg) formulated in IF7-PTX-NP showed significant anticancer efficacy, delaying the growth of MCF-7/ADR tumors. The same efficacy was only obtained with an 8-fold dose of paclitaxel (8 mg/kg) as Taxol plus XR9576, a potent P-gp inhibitor. The anticancer efficacy of IF7-PTX-NP was strongly associated with the improved antiangiogenic effect, evident as a dramatic reduction in the tumor microvessel density and pronounced increase in apoptotic tumor cells, with no obvious toxicity to the mice. This nano-DDS, which targets the tumor neovasculature, offers a promising strategy for the treatment of multidrug-resistant cancer.
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