JOURNAL OF MOLECULAR LIQUIDS
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2019
·
IF 4.561
Xiaoqing Yuan,Zhiyong Li,Ying Feng,Yuanchao Pei,Huiyong Wang,Diandian Liu,Dayu Wang,Jianji Wang
At present, it is still a challenge for reversible regulation of phase behavior and microstructure of microemulsions with less energy input and no composition change of the system. Photo-responsive microemulsions provide a potential way to solve these problems. In this work, 10 kinds of photo-responsive ionic liquids (ILs) with azobenzene group were used as photo-responsive surfactants to form microemulsions with water and some alcohols. Factors affecting the phase behavior and sub-regions of microemulsions, such as chemical structure of the ILs, temperature, alcohols properties and UV irradiation , were studied by conductivity, small-angle X-ray scattering, dynamic light scattering and cryo-TEM techniques. It was found that azobenzene-based ILs with a more hydrophilic head group and a shorter alkyl spacer length were favor of the formation of the microemulsions. The phase behavior of the microemulsions only slightly changed after UV irradiation, however, the area of O/W and bi-continuous sub-regions of the microemulsion could be regulated by UV irradiation. At the same time, droplets size increased after UV light irradiation , and could be restored close to the initial value by alternative vis-light irradiation.
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高影响因子
GREEN CHEMISTRY
·
2019
·Vol. 21
·期 3
·606-613
·
IF 9.405
Zhenbing Xie,Bingfeng Chen,Haoran Wu,Mingyang Liu,Huizhen Liu,Jianling Zhang,Guanying Yang,Buxing Han
Transformation of biomass or biomass-based feedstocks into fuels or valuable chemicals is of great importance for the sustainable development of our society. Mesoporous Al2O3–ZrO2 with different Al : Zr molar ratios was prepared by the sol–gel method, and Cu–Ni/Al2O3–ZrO2 catalysts were fabricated by the impregnation method. The catalytic performances of the bifunctional catalysts were studied in the selective hydrogenation of levulinic acid (LA) into 2-methyltetrahydrofuran (MTHF). It was demonstrated that both Cu : Ni and Al : Zr ratios affected the selectivity to MTHF significantly. The bimetallic catalysts Cu–Ni/Al2O3–ZrO2 containing 10 wt% Ni and 10 wt% Cu gave 99.8% MTHF selectivity at full conversion of LA when the Al : Zr ratio was 9 : 1. The outstanding catalytic performance of the catalyst is related to the mesoporous structure, the acidic properties of the support and the synergistic effect between Cu and Ni. The catalyst could be reused five times without a considerable loss of catalytic activity and selectivity.
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JOURNAL OF MOLECULAR LIQUIDS
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2018
·
IF 4.513
Kemeng Shi,Christian Marcus Pedersen,Zhaohui Guo,Yanqiu Li,Hongyan Zheng,Yan Qiao,Tuoping Hu,Yingxiong Wang
The tautomer distributions of d ‑fructose, a popular model compound for biorefinery , in various lower alcohols and DMSO‑ d 6 (ROHs/DMSO‑ d 6 ) mixtures at 298 K were investigated by quantitative 13 C NMR. The tautomer distributions of d ‑fructose in ethanol/DMSO‑ d 6 and methanol/DMSO‑ d 6 with different volume ratios of alcohols to DMSO‑ d 6 were also examined. For these normal alcohols (methanol, ethanol, n ‑propanol and n ‑butanol)/DMSO‑ d 6 , the tautomer distribution of d ‑fructose in methanol/DMSO‑ d 6 exhibited the shortest equilibration time (46 h) and the lowest concentration of β‑furanose (39.0%) at equilibrium. The fraction of fructofuranose (α‑furanose and β‑furanose) at equilibrium and time needed to reach equilibrium in branched chain alcohols/DMSO‑ d 6 obey the following order: 2‑propanol/DMSO‑ d 6 (62.2%, 320 h) > tert ‑butanol/DMSO‑ d 6 (61.6%, 307 h) > 2‑butanol/DMSO‑ d 6 (60.6%, 216 h) > isobutanol/DMSO‑ d 6 (57.8%, 134 h). For the diols/DMSO‑ d 6 , the time for the tautomer distribution of d ‑fructose to reach the equilibrium was found to be: 1,4‑butanediol/DMSO‑ d 6 (113 h) > 1,2‑propanediol/DMSO‑ d 6 (38 h) > ethylene glycol/DMSO‑ d 6 (36 h). For ethanol/DMSO‑ d 6 and methanol/DMSO‑ d 6 with respectively different volume ratios, the experimental results showed that the high concentration of ethanol or methanol increases the conversion rate of tautomers.
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JOURNAL OF CHROMATOGRAPHY A
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2018
·
IF 3.716
Yinhui Yang,Meiling Qi,Jinliang Wang
This work describes the separation performance of a star-shaped truxene-based material (denoted as EDOTT) as the stationary phase for capillary gas chromatography (GC). The EDOTT capillary column achieved the column efficiency of 5920 plates/m by n -dodecane, 4890 plates/m by naphthalene and 3960 plates/m by 1-octanol at 120 ℃. Its selectivity and retention behaviour were investigated by a number of mixtures of diverse analytes and their isomers. As a result, it showed advantageous performance for separations of apolar to polar analytes, especially phenols and alcohols, over its analogous TTT, TDT and TFT stationary phases. In addition, the EDOTT capillary column was investigated for its column loadability, repeatability and thermal stability, and was finally applied for the determination of isomer impurities in real samples. This work provides an alternative truxene-based stationary phase with high selectivity for polar analytes and demonstrates the key role of structural modification in developing a family of stationary phases with specific selectivity for targeted analytes.
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PubMed
高影响因子
FLUID PHASE EQUILIBRIA
·
2018
·
IF 2.197
Pengshuai Zhang,Rui Zhao,Chi Zhang,Tao Li,Baozeng Ren
The solubility of cyromazine in the pure solvents (methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 1-heptanol, water, acetone, 2-propanol, isobutanol , 3-methyl-1-butanol and 2-butanol) at 283.15 K–323.15 K, cyromazine in the pure solvents (acetic acid and acrylic acid) at 293.15 K–333.15 K and cyromazine in the pure solvent of propanoic acid at 278.15 K–318.15 K. were measured by a laser dynamic method under atmospheric pressure. The experimental results show that the mole fraction solubility of cyromazine in the sixteen pure solvents decreased according to the following order: acrylic acid > acetic acid > propanoic acid > methanol > ethanol ≈ water > 1-propanol > 1-butanol >1-pentanol >1-hexanol > 1-heptanol > 3-methyl-1-butanol ≈ (2-propanol, 2-butanol, isobutanol and acetone). In order to facilitate industrial application (to improve the purity of cyromazine by crystallization in industry) and other research studies, the experimental solubility data are correlated with the five thermodynamic models: modified Apelblat equation, λh equation, non-random two liquid (NRTL) model equation, Wilson model equation and van't Hoff equation. Moreover, the mixing Gibbs energy (Δ mix G ), mixing entropy (Δ mix S ), mixing enthalpy (Δ mix H ), activity coefficient ( γ 1 ∞ ) at infinitesimal concentration and reduced excess enthalpy ( H 1 E , ∞ ) were obtained and the mixing process of cyromazine in the selected solvents are evaluated based on the Wilson model. The relatively close values of γ 1 ∞ and γ 1 indicated that the cyromazine -selected solvents solution systems are not highly non-ideal.
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ORGANIC ELECTRONICS
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2018
·
IF 3.68
Zhanfeng Li,Jinbo Chen,Jingkun Ren,Qinjun Sun,Hua Wang,Junsheng Yu,Yuying Hao
Organometal halide perovskite solar cells (PSCs) have demonstrated exceptional, unparalleled progress in solar cell performance by optimizing the perovskite film morphology, composition , interfaces, and charge collection efficiency. In this work, a PbBr 2 pre-coating layer (PCL) was employed to effectively fabricate a relatively uniform composition perovskite film with large crystal sizes and no voids. We demonstrated that carrier recombination is reduced and charge collection is improved by the interface and interior passivation in PSCs fabricated with PCL process, which leads to a striking enhancement in open-circuit voltage and short circuit current. As a result, a promising power conversion efficiency of 17.38%, showing more than 10% enhancement over the reference devices, was realized in the passivated invert planar PSCs with negligible hysteresis and stable photocurrent output. This study gives a novel compositional passivation process to produce high-efficiency halide PSCs with improved process reproducibility.
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高影响因子
CATALYSIS TODAY
·
2014
·
IF 3.309
Huiling Li,Aojie Deng,Junli Ren,Changyu Liu,Wenju Wang,Feng Peng,Runcang Sun
One of the most promising strategies for furfural production is to extract continually the target product from the aqueous solution utilizing organic solvents. With the aim to develop an ecologically viable catalytic pathway for furfural production without the addition of mineral acids, we presented a modified biphasic system using a solid acid (SO 4 2− /TiO 2 -ZrO 2 /La 3+ ) as catalyst for producing furfural from xylose. Different kinds of aprotic organic solvents (DMSO, DMF and DMI) in water phase and 2-butanol in organic phase (MIBK) were investigated as reaction media. Furfural yield and xylose conversion efficiency were dependent on the amounts of aprotic organic solvents and 2-butanol, the solid/liquid ratio, and the volume ratio of the organic phase and the aqueous phase as well as the reaction temperature and time. As a result, DMI showed the best performance on improving furfural yield during the furfural production. 3563.3 μmol of furfural/g of xylose with 97.9% xylose conversion efficiency was obtained after 12 h at 180 °C when the volume ratios of water to DMI and MIBK to 2-butanol were 8:2 and 7:3, respectively.
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RSC Advances
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2017
·Vol. 7
·期 54
·33714-33725
·
IF 3.108
Jianhua Li,Haiyan Liu,Tingting An,Yuanyuan Yue,Xiaojun Bao
This article describes a novel method to dealuminate and realuminate H-beta zeolites as catalysts for removing organic acids from bio-oils via their esterification reactions with alcohols. Modified H-beta zeolites were prepared by leaching with solutions of oxalic acid, DL-malic acid, and DL-tartaric acid that have different numbers of hydroxyl groups. The results showed that, while all three organic acids can dealuminate the parent H-beta zeolite, with Al(VI)a atoms and Al(IV)c ones being preferentially removed, they show quite different realumination abilities, with tartaric acid with two hydroxyl groups having the highest realumination ability. The concomitance of dealumination and realumination and their dependence on the hydroxyl group numbers of the organic acids provide the possibility of finely tuning the Al and acidity distributions of the resulting zeolites. Among the three acid treated H-beta zeolites, the one obtained from malic acid leaching exhibited the best performance in catalyzing the esterification reaction between acetic acid and sec-butyl alcohol, attributed to its suitable quantity and density of medium and strong Brönsted acid sites and enhanced aluminum gradient. The catalytic results obtained in a fixed-bed microreactor revealed that the malic acid leached H-beta exhibited dramatically enhanced catalytic performance compared to the commercial ion-exchange resin Amberlyst® 15, demonstrating great potential for industrial application.
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Nano Research
·
2017
·Vol. 11
·期 2
·1004-1017
·
IF 7.354
Wu Tianxing,Zhu Xiaoguang,Wang Guozhong,Zhang Yunxia,Zhang Haimin,Zhao Huijun
Electrocatalytic synthesis of value-added chemicals is attracting significant research attention owing to its mild reaction conditions, environmental benignity, and potentially scalable application to organic synthetic chemistry. Herein, we report the preparation of a single-crystalline NiS 2 nanostructure film of ∼ 50 nm thickness grown directly on a carbon fiber cloth (NiS 2 /CFC) by a facile vapor-phase hydrothermal (VPH) method. NiS 2 /CFC as an electrocatalyst exhibits activity for both the oxygen evolution reaction (OER) and the hydrogen evolution reaction (HER) in alkaline media. Furthermore, a series of alcohols (2-propanol, 2-butanol, 2-pentanol, and cyclohexanol) were electrocatalytically converted to the corresponding ketones with high selectivity, efficiency, and durability using the NiS 2 /CFC electrode in alkaline media. In the presence of 0.45 M alcohol, a remarkably decreased overpotential (∼ 150 mV, vs. RHE) at the NiS 2 /CFC anode compared with that for water oxidation to generate O 2 , i.e., the OER, in alkaline media leads to significantly improved H 2 generation. For instance, the H 2 generation rate in the presence of 0.45 M 2-propanol is almost 1.2-times of that obtained for pure water splitting, but in a system that employs an applied voltage at least 280 mV lower than that required for water splitting to achieve the same current density (20 mA·cm –2 ). Thus, our results demonstrate the applicability of our bifunctional non-precious-metal electrocatalyst for organic synthesis and simultaneous H 2 production.
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高影响因子
FUEL
·
2017
·
IF 4.601
Yaoyao Ying,Dong Liu
This paper explored the effects of butanol isomers, n -butanol, iso -butanol, sec -butanol, and tert -butanol, as fuel-side additives on soot nanostructure and reactivity in ethylene inverse diffusion flames (IDF) and normal diffusion flames (NDF). The variations of structures and oxidation rates among the soot samples derived from ten different flames were studied and compared using high resolution transmission electron spectroscopy (HRTEM), Raman spectroscopy, thermogravimetric analyzer (TGA), surface area and porosimetry analyzer, and elemental analyzer. Results demonstrated that soot from IDF with the additions of butanol isomers had irregular shapes with film-like materials and highly heterogeneous nanostructures, which showed both amorphous carbon and fullerenic lamellae. The shells presented more prevalently in tert -butanol-doped IDF soot, which had the longest fringe length and smallest fringe tortuosity. Whereas in the NDF as butanol isomers were individually added, the soot samples were aggregated by several tens or hundreds nearly rounded particles. All the NDF soot exhibited a typical core-shell structure with extended and planar lamellae. Soot from sec -butanol added NDF presented the lowest degree of graphitization with the shortest fringe length and largest fringe tortuosity. The TGA results revealed that the oxidation rates of the IDF soot particles were much higher than that of the NDF soot. Moreover, when butanol isomers were individually added in IDF, soot produced with n -butanol (1.34E-03 s −1 ) showed the highest reactivity with the least degree of crystallization in structure, followed by iso -butanol (1.31E-03 s −1 ), sec -butanol (1.29E-03 s −1 ) and tert -butanol (1.14E-03 s −1 ) in the sequence of reactivity. However, the oxidation rates of the soot samples generated from butanol isomers-doped NDF were in the order of sec -butanol (4.26E-04 s −1 ), tert -butanol (3.70E-04 s −1 ), n -butanol (3.52E-04 s −1 ) and iso -butanol (3.23E-04 s −1 ) from the highest to lowest. The results confirmed a relationship on structure-property between soot nanostructure and reactivity.
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RSC Advances
·
2017
·Vol. 7
·期 3
·1200-1205
·
IF 3.108
Haian Xia,Siquan Xu,Li Yang
The development of sustainable techniques to convert lignocellulosic materials into value-added chemicals remains a significant challenge. Herein, we report a novel technique to directly convert wheat straw to furan compounds, bio-oils, and phosphate fertilizers. Untreated wheat straw was initially converted into 5-hydroxymethylfurfural (HMF) and furfural in a biphasic reaction system using FePO4 and NaH2PO4 as co-catalyst. The remaining FePO4 in the solid residues was used as the catalyst to pyrolyze the solid residues, producing bio-oils and bio-char-based phosphate fertilizers. This combination of FePO4 and NaH2PO4 co-catalyst exhibited higher selectivity towards HMF and furfural production than using only FePO4 as a catalyst in the conversion of wheat straw. The maximum HMF yield, 44%, was obtained when the reaction was carried out at 160 °C for 60 min, while the highest furfural yield, 92%, was achieved when the reaction occurred at 150 °C for 60 min. This reaction system is one of the most effective reaction systems to date for the conversion of wheat straw. Excessive Brønsted or Lewis acid sites (Fe ions) cannot give high yields of HMF and furfural due to the formation of by-products, indicating that a synergistic combination of Brønsted and Lewis acid sites is critical to obtain high yields of furan compounds. Interestingly, FePO4 could effectively catalyze the pyrolysis of unconverted cellulose into new compounds, such as 5-methylfuran and 2,5-methylfuran, which is not observed in non-catalyzed pyrolysis.
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高影响因子
FUEL PROCESSING TECHNOLOGY
·
2016
·
IF 3.847
Haian Xia,Siquan Xu,Xiaopei Yan,Songlin Zuo
It is of great significance to explore and develop a cost-effective and environmentally friendly way to covert cellulosic materials into 5-hydroxymethylfurfural (5-HMF). An inexpensive FePO 4 catalyst, which is insoluble at room temperature but can be partially dissolved and behaves as homogeneous catalyst at elevated temperatures, was used to directly convert cellulose into 5-HMF. The effect of various reaction conditions including reaction temperature, reaction time, cellulose concentration and catalyst amount on the conversion of cellulose and 5-HMF yield was investigated. A 5-HMF yield up to 49.5 mol% was achieved at 160 °C for 60 min with the FePO 4 catalyst, which is comparable to the highest yield of 5-HMF obtained in ionic liquid or homogeneous catalysis reaction systems. Moreover, this unique catalyst is readily separated from the aqueous solution via precipitation after cooling to room temperature since it is insoluble at room temperature. The catalyst can be used over five successive cycles although the amorphous FePO 4 underwent the structural transformation from an amorphous phase into a new crystalline form of FePO 4 , evidenced by XRD, IR, and visible Raman spectroscopic results. The soluble iron species, such as Fe 3 + species, act as Lewis acid sites catalyzing isomerization of glucose to fructose followed by the dehydration of fructose into 5-HMF catalyzed by H + ions.
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