GREEN CHEMISTRY
·
2014
·Vol. 16
·期 5
·2580-2586
·
IF 6.852
Anqing Zheng,Zengli Zhao,Sheng Chang,Zhen Huang,Kun Zhao,Hongxiang Wu,Xiaobo Wang,Fang He,Haibin Li
We firstly propose the coupling conversion of bio-derived furans and methanol over ZSM-5 for enhancing aromatic production. The coupling conversion of bio-derived furans and methanol was conducted in a continuous fixed bed reactor. 2-Methylfuran (MF) was used as a probe molecule to identify the possible reaction pathways. The effects of the methanol to MF molar ratio, reaction temperature and weight hourly space velocity (WHSV) on the product distribution from the coupling conversion of MF and methanol were investigated. The experimental results showed that the aromatic yield from the coupling conversion of MF and methanol is about 5.2 times higher than that of the catalytic fast pyrolysis of only MF. In addition, it can also enhance the yield of olefins, the selectivity of xylenes and reduce coke formation. These results indicate that there is a significant synergistic effect between MF and methanol. The synergistic effect could be attributed to the methanol-to-olefins reactions, the Diels–Alder reactions of furans with olefins, and the alkylation reaction of benzene/toluene with methanol occurring during the coupling conversion of MF and methanol. The reaction conditions for maximizing the synergistic effect were a methanol to MF molar ratio of 2 at 550 °C. Moreover, the comparative study of the coupling conversion of different bio-derived furans (MF, 2,5-dimethylfuran (DMF), furfural (FF) and furfuryl alcohol (FA)) and methanol were also considered in this study. The coupling conversion of DMF and methanol exhibited maximum yields of aromatics, olefins and a minimum yield of coke, suggesting that DMF is the best candidate of bio-derived furans for aromatic production in the coupling conversion of bio-derived furans and methanol.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2014
·
IF 2.235
Yimei Wang,Bing Liu,Kecheng Huang,Zehui Zhang
The paper deals with oxidation of the biomass-derived model molecule 5-(hydroxymethyl)furfural (HMF) catalyzed by the trimetallic mixed oxide RuCo(OH)2CeO2. The catalyst RuCo(OH)2CeO2 was prepared through alkali hydrolysis of RuCl3, Co(NO3)2, and Ce(NO3)2 and characterized by X-ray diffraction and transmission electron microscopy techniques. RuCo(OH)2CeO2 showed high catalytic activity for aerobic oxidation of HMF under mild conditions (in the case of atmospheric oxygen pressure). Various reaction parameters such as the reaction temperature, catalyst amount, solvent, and oxidant were explored. Results demonstrated that the oxidant and solvent showed a remarkable effect on the aerobic oxidation of HMF to 2,5-diformylfuran (DFF). Under optimal conditions, DFF was obtained in a high yield of 82.6% with HMF conversion of 96.5% after 12 h at 120 °C. More importantly, the catalyst could be reused several times without significant loss of its catalytic activity.
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RSC Advances
·
2013
·Vol. 4
·期 23
·11664-11672
·
IF 2.562
Yunlei Zhang,Jianming Pan,Mengying Gan,Hongxiang Ou,Yongsheng Yan,Weidong Shi,Longbao Yu
By grafting –SO3H and Cr(III) onto the surface of treated attapulgite (ATP) and halloysite nanotubes (HNTs), two acid–chromic chloride bi-functionalized catalysts i.e. ATP–SO3H–Cr(III) and HNTs–SO3H–Cr(III) were successfully synthesized. Then the as-prepared catalysts were characterized by SEM, TEM, EDS, XPS, BET, NH3–TPD, nitrogen adsorption–desorption and TG analysis. The catalytic activities of the synthesized ATP–SO3H–Cr(III) and HNTs–SO3H–Cr(III) were evaluated for the conversion of one-pot cellulose to 5-hydroxymethylfurfural (HMF) in an ionic liquid ([EMIM]-Cl) system. The amount of catalyst, reaction time and reaction temperature were optimized for cellulosic conversion over the two catalysts, resulting in a maximum yield of 31.20% for ATP–SO3H–Cr(III) and 41.22% for HNTs–SO3H–Cr(III) under the optimized conditions. The clay supported catalysts developed in this work showed greatly improved performances in cellulose-to-HMF conversion over other solid catalysts. In addition, the prepared catalysts could be very easily recycled, at least three times for ATP–SO3H–Cr(III) and twice for HNTs–SO3H–Cr(III) without significant loss of activity.
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ONCOLOGY REPORTS
·
2015
·Vol. 34
·期 6
·3147-3155
·
IF 2.301
Lili Zhang,Jie Zhang,Li Chen,Jianli Wang
Autophagy is an intracellular multi-step catabolic degradation process that involves the degradation and recycling of cellular proteins and cytoplasmic damaged organelles to maintain cellular homeostasis and reduction of metabolic stress. Numerous studies have indicated the importance of autophagy in cancer, but the role of autophagy in human skin squamous cell carcinoma (SSCC) development and response to therapy it is still unclear. In the present study, we investigated the role of autophagy in SSCC and the relationship with chemotherapy sensitivity. The present study demonstrated that autophagy related gene the microtubule-associated protein 1 light chain 3 (LC3) expression was low in SSCC. The negative correlation with Bcl2 and survivin, and the chemotherapy drug 5-FU increased the level of autophagy and the autophagy inhibitor 3-MA inhibited this effect in SSCC cells, time- and dose-dependently. When SSCC cells were treated first with 3-MA and then with 5-FU, the inhibition of proliferation, migration, invasion and apoptosis of SSCC cells was enhanced. Our results suggested the possibility of autophagy as a potential target in SSCC therapy and 3-MA and 5-FU combination treatment may be an effective SSCC therapy via autophagy modulating.
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PubMed
高影响因子
Journal of Energy Chemistry
·
2015
·
IF 2.352
Guiquan Zhang,Xin Zhang,Ting Bai,Tengfei Chen,Wentao Fan
The coking kinetics and reaction-regeneration on Zn/HZSM-5 (Zn/HZ) catalyst in the conversion of methanol to aromatics were investigated. The highest initial benzene, toluene and xylene (BTX) yield of ca. 67.7% was obtained on fresh Zn/HZ catalyst, which showed the worst catalytic stability. The cycle of reaction-regeneration significantly modified the texture and acidity of Zn/HZ catalyst, which in turn affected its catalytic performance and coking behavior in methanol conversion to BTX. The residual carbon located on the surface of Zn/HZ catalyst led to the decrease of acid sites and the change on the acid sites distribution, which played an important roles on its activity and deactivation. It was found that the high B/L ratio and the low total acid sites concentration of the Zn/HZ catalyst favored to the high BTX yield and good catalytic stability in methanol conversion.
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Materials Science & Engineering C-Materials for Biological Applications
·
2013
·
IF 2.404
Fan Shi,Shixing Gong,Li Xu,Huanhuan Zhu,Zhenfan Sun,Wei Sun
In this paper, a graphene (GR) ionic liquid (IL) 1-octyl-3-methylimidazolium hexafluorophosphate and chitosan composite-modified carbon molecular wire electrode (CMWE) was fabricated by a drop-casting method and further applied to the sensitive electrochemical detection of adenosine-5′-monophosphate (AMP). CMWE was prepared with diphenylacetylene (DPA) as the modifier and the binder. The properties of modified electrode were examined by scanning electron microscopy, cyclic voltammetry and electrochemical impedance spectroscopy. Electrochemical behaviors of AMP was carefully investigated with enhanced responses appeared, which was due to the presence of GR-IL composite on the electrode surface with excellent electrocatalytic ability. A well-defined oxidation peak of AMP appeared at 1.314 V and the electrochemical parameters were calculated by electrochemical methods. Under the selected conditions, the oxidation peak current of AMP was proportional to its concentration in the range from 0.01 μM to 80.0 μM with the detection limit as 3.42 nM (3 σ ) by differential pulse voltammetry. The proposed method exhibited good selectivity and was applied to the detection of vidarabine monophosphate injection samples with satisfactory results.
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PubMed
高影响因子
PLoS One
·
2015
·Vol. 10
·期 11
·e0141467
·
IF 3.234
Xiu-Zeng Bi,Wei-Hua Pan,Xin-Ping Yu,Zong-Ming Song,Zeng-Jin Ren,Min Sun,Cong-Hui Li,Kai-Hui Nan
This study was designed to investigate whether 5-fluorouracil (5-Fu)-polycaprolactone sustained-release film in Ahmed glaucoma valve implantation inhibits postoperative bleb scarring in rabbit eyes. Eighteen New Zealand white rabbits were randomly divided into three groups (A, B and C; n = 6 per group). Group A received combined 5-Fu-polycaprolactone sustained-release film application and Ahmed glaucoma valve implantation, group B received local infiltration of 5-Fu and Ahmed glaucoma valve implantation, and group C received Ahmed glaucoma valve implantation. Postoperative observations were made of the anterior segment, intraocular pressure, central anterior chamber depth, blebs, drainage tube, and accompanying ciliary body detachment. The pathology of the blebs and surrounding tissues were observed at month 3 postoperatively. We revealed that the 5-Fu-polycaprolactone sustained-release film maintained a release concentration range of 13.7 ± 0.12 to 37.41 ± 0.47 μg/ml over three months in vitro . Postoperatively, diffuse blebs with ridges were found in all eyes in group A, two blebs were observed in group B, and no bleb formation was present in group C. The postoperative central anterior chamber depth in group A was significantly less than that of the other two groups. The postoperative intraocular pressure of group A stabilized at 6.33–8.67 mmHg, whereas that of group C gradually remained at 7.55–10.02 mmHg. The histopathology showed that the fibrous tissue thickness of the blebs in group A was significantly thinner than that of the other groups. We conclude that the 5-Fu-polycaprolactone sustained-release film had a sustained drug release effect, which promoted the inhibition of bleb scarring after Ahmed glaucoma valve implantation.
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PubMed
高影响因子
Optical Materials Express
·
2015
·Vol. 5
·期 8
·1759-1771
·
IF 2.844
Jing Liu,Nana Li,Ruitao Wu,Yuxiang Zhao,Qiuqiang Zhan,Sailing He
Upconversion nanoparticles (UCNPs) is a class of promising probes
widely used in protein molecules imaging due to the no photobleaching
and non-blinking emission. However, it is still remained challenging
to synthesize a type of ultra-small but bright UCNPs. In this paper, a
new class of efficient sub-5-nm upconversion nanodots (UCNDs) was
elaborately designed and experimentally demonstrated. The proposed
uniform UCNDs comprise two parts: a 3.5-nm Ln3+-doped
ZrO2 core and 0.5-nm NaYF4 shell. The emission
intensity of the proposed UCNDs was measured to be more than 10 times
brighter than that of the conventional 10-nm NaYF4 UCNPs.
Under 300 kW·cm−2 irradiance excitation, the 15 mol%
Er3+-doped UCNDs exhibit an 18-fold enhanced intensity and
one fifth emission lifetime compared to the 0.5 mol%
Er3+-doped ones. Using the biocompatible UCNDs, the
aptamer-mediated proteins-targeted imaging was performed and
demonstrated high efficiency. These ultra-small, efficient UCNDs would
have great potentials in rapid scanning and cellular imaging.© 2015 Optical Society of
America
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JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2014
·
IF 2.045
Yongzhao Zhang,Xia Guo,Jianbing Ji
(2R,3S,4S,5S)-6-(Hydroxymethyl)-tetrahydro-2H-pyran-2,3,4,5-tetraol (d-glucose) solubility in 1-dodecanol, 1-decanol, and 1-octanol from 343.15 K to 393.15 K was determined, respectively. The solubility of d-glucose increased with an increase in temperature and decreased with the increase of fatty alcohol chain length. The modified UNIQUAC model, S-UNIFAC model, and mS-UNIFAC model were applied to predict the solubility data; the interaction parameters were determined. Of the three models, the modified UNIQUAC model showed better prediction accuracy.
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Molecular Catalysis
·
2017
·
IF 0
Qi Wu,Yiming He,Huili Zhang,Zhiyuan Feng,Ying Wu,Tinghua Wu
Metal-free graphitic carbon nitride (g-C 3 N 4 ) catalyst was synthesized by a simple calcination of melamine. The characterization results indicate that the water treatment during preparation process is in favor of the formation of pore structure, enhancing light-harvest ability and suppressing the recombination of the photoexcited electron-hole pair. The as-prepared g-C 3 N 4 catalyst was applied in the photocatalytic selective oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF). The effects of incident wavelength, solvent, reaction time and scavenger on the photocatalytic performance were investigated. The results indicate that O 2 − plays a key role as dominant active species in photocatalytic oxidation of 5-HMF. Compared with visible light, the UV light illumination is easier to cause the overoxidation of target product and thus leads to a lower DFF selectivity. Under the irradiation of light with wavelength >400 nm, the highest DFF selectivity of 85.6% can be achieved with HMF conversion of 31.2% in the presence of O 2 .
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ChemCatChem
·
2016
·Vol. 8
·期 8
·1557-1563
·
IF 4.724
Qingping Ke,Mingzhou Wu,Chao Wang,Guanzhong Lu
Graphical Zeolite my fire : Ullmann coupling reactions of phenols with nitro-substituted aryl halides are catalyzed by rare-earth-doped mesoporous AlPO-5 zeolites in the absence of ligands. The LaAlPO-5-MAlPO-5-M zeolite is an excellent catalyst for Ullmann coupling reactions of phenols and nitro-substituted aryl halides. Mesoporous LaAlPO-5 has an excellent stability and recyclability in the Ullmann coupling of p -X-nitrobenzene (X=Cl, Br, and I) with 2-naphthol. Heterogeneous catalytic reactions of aromatic organic molecules over zeolite catalysts present many challenges because of the shape selectivity of the micropores of conventional zeolites that limits the diffusion of aromatic molecules. Herein, Ullmann coupling reactions of phenols with nitro-substituted aryl halides were catalyzed by rare-earth-doped mesoporous AlPO-5 zeolites in the absence of ligands. The AlPO-5-MAlPO-5-M zeolites had a pure AFI structure and consisted of spherical particles assembled by nanofibers. The rare-earth elements were highly dispersed in the AlPO-5-MAlPO-5-M samples. The LaAlPO-5-MAlPO-5-M zeolite is an excellent catalyst for Ullmann coupling reactions of phenols and nitro-substituted aryl halides. Mesoporous LaAlPO-5 has an excellent stability and recyclability in the Ullmann coupling of p -X-nitrobenzene (X=Cl, Br, and I) with 2-naphthol. These results are important in the exploration of attractive Ullmann coupling reactions and in the development of mesoporous zeolite catalysts for other organic reactions.
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TETRAHEDRON
·
2016
·
IF 2.645
Xiong-Wei Liu,Zhen Yao,Jun Yang,Zhi-Yong Chen,Xiong-Li Liu,Zhi Zhao,Yi Lu,Ying Zhou,Yu Cao
A facile and efficient methodology was developed for the synthesis of isoxazole-fused spiropyrrolidine oxindoles 3–5 via a 1,3-dipolar cycloaddition reaction of 3-methyl-4-nitro-5-alkenyl-isoxazoles with azomethine ylides (thermally generated in situ from isatin derivatives and proline or thioproline or sarcosine). Products bearing adjacent quaternary-tertiary centers were smoothly obtained in high yields (up to 90% yield) with good diastereoselectivity (up to 20:1). Furthermore, their biological activity has been preliminarily demonstrated by in vitro evaluation against human prostate cancer cells PC-3, human lung cancer cells A549 and human leukemia cells K562 by the MTT-based assays using the commercially available standard drug Cisplatin as a positive control. These results suggested that most of isoxazole-fused spiropyrrolidine oxindoles 3–5 showed considerable cytotoxicities to these three cell lines K562, A549 and PC-3, and that isoxazole-fused spiropyrrolidine oxindoles may be potential leads for further biological screening.
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