RSC Advances
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2015
·Vol. 5
·期 114
·93937-93944
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IF 3.84
Ji Li,Zhigang Han,Yongpeng Zou,Bo Yu
In this study, an efficient microwave-assisted extraction (MAE) method using green deep eutectic solvents (DESs) was developed for the extraction of the major catechins in Camellia sinensis leaves. A series of choline chloride-based DESs were prepared, and DES-4, which was composed of choline chloride and lactic acid, was observed to possess the best extraction performance for the target catechins. Moreover, the main factors affecting the extraction efficiency were optimized using Box–Behnken design (BBD) combined with response surface methodology (RSM), and the optimal conditions were as follows: temperature 66 °C, duration 8 min and solvent/material ratio of 35 mL g−1. Under these conditions, a total extraction yield of 153.7 ± 5.2 mg g−1 was obtained. In addition, the separation of the target catechins from DES-based extraction solution was performed using AB-8 macroporous resin with recovery yields from 75.2% to 86.1%. The present study provided fundamental data for the development of DES-based extraction methods in food and pharmaceutical fields.
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高影响因子
Catalysts
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2015
·Vol. 5
·期 4
·1636-1648
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IF 2
Rui Wang,Xiaolin Xie,Yanxiu Liu,Zhigang Liu,Guofang Xie,Ning Ji,Lizhi Ma,Mingquan Tang
The kiwifruit industry is booming worldwide. As a result, a great deal of kiwifruit waste residue (KWR) containing monosaccharides is produced and discarded. This material shows great potential for the production of platform chemicals. In this study, a series of Nb/Al oxide catalysts were synthesized via a facile and low-cost coprecipitation method, and their structures were characterized using: thermal gravimetric analysis (TGA), XRD, FESEM, TEM, X-ray photoelectron spectroscopy (XPS), NH3-TPD, N2adsorption-desorption, and FTIR-Pyridine adsorption. Experimental results of sugar-to-levulinic acid (LA) conversion revealed that the 20%Nb/Al oxide catalyst provided the highest catalytic performance and durability in terms of LA yield from fructose (74.2%) at 463 K after 10 min and from glucose (47.5%) at 473 K after 15 min. Notably, the 20% Nb/Al oxide catalyst with a 10% dosage is capable of converting kiwifruit waste residue to LA at 473 K after 10 min. In conclusion, the enhanced catalytic performance was obtained due to the high acidity, and large surface areaof Nb/Al oxide catalyst.Keywords:levulinic acid;kiwifruit waste residue (KWR);heterogeneous catalysis;Nb/Al oxide catalyst
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高影响因子
Energy Technology
·
2015
·Vol. 4
·期 5
·600-609
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IF 2.824
Yating Shen,Yunlei Zhang,Yao Chen,Yongsheng Yan,Jianming Pan,Meng Liu,Weidong Shi
Stable oil-in-water high internal phase emulsions (HIPEs) with an internal phase volume fraction of 85 % were stabilized using Tween 85. The prepared poly(HIPEs) were first investigated as adsorbents to treat water polluted with Cr III , and then the catalysts with Lewis acidic sites was synthesized. The catalysts with Brønsted acidic sites were obtained by ion-exchanging. The as-prepared HIPEs–Cr III (PEs–Cr III ) and HIPEs–SO 3 H (PEs–SO 3 H) possess open-cell structure, interconnecting pores, and strong acidity, they are utilized as highly efficient catalysts for the conversion of biomass to 5-hydroxymethylfurfural (HMF). These results showed maximum production yields for cellulose, glucose, and fructose of 37.0 %, 58.0 %, and 80.8 %, respectively. PEs–Cr III and PEs–SO 3 H can be very easily recycled at least four times without significant loss of activity. Herein, a new method is presented to transform cellulose by using two catalysts in a one-pot process for meeting the varying demands involved at different reaction stages.
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高影响因子
FOOD SCIENCE AND BIOTECHNOLOGY
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2015
·Vol. 24
·期 3
·867-873
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IF 0.653
Niu Liying,Li Dajing,Liu Chunquan,Liu Fuguo
Lipoxygenases (LOX) in milk-stage sweet corn and waxy corn were extracted using a phosphate buffer (pH 7.0) and enzyme activities were determined using linoleic acid as a substrate. Michaelis constant ( K m) values, decimal reduction times (D value), temperature sensitivity parameters (Z value), and activation energies ( E a) were calculated. Enzymes from both corn types followed first-order inactivation kinetics within 0–25 min and 50–70°C. However, enzymes exhibited different pH profiles and affinities toward linoleic acid. Km values (4.34 and 1.40 mM for sweet corn and waxy corn, respectively), heat stability values, and Ea values (116.81 and 246.82 kJ/mol) were different. Waxy corn LOX was more heat stable below 65–C with a higher D value, but was more temperature sensitive with a lower Z value. The different characteristics suggested the presence of different isoenzymes and necessitated the use of different parameters for blanching.
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高影响因子
SENSORS AND ACTUATORS B-CHEMICAL
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2014
·
IF 3.84
Qu Sheng,He Mei,Huimin Wu,Xiuhua Zhang,Shengfu Wang
Platinum–cobalt (Pt x Co 1− x , x = 0.70, 0.55) alloy nanoparticles have been successfully fabricated by the chemical reduction method, using carbon (Vulcan XC-72) as support. The physical properties of the materials were characterized by X-ray diffraction, and transmission electron microscopy , respectively. The electrochemical performance of the Pt x Co 1− x /C catalysts was evaluated by cyclic voltammetry , electrochemical impedance spectroscopy and chronoamperometry . Electrochemical measurements indicated that the oxidation current of glucose is linear to its concentration from 0.10 to 14.20 mM with high sensitivity of 73.60 μA mM −1 cm −2 . In addition, the interference from the oxidation of fructose, uric acid , acetamidophenol and ascorbic acid could be effectively avoided. Meanwhile, the non-enzymatic glucose sensors exhibited excellent selectivity, stability and repeatability. Thus, this novel non-enzyme sensor has potential application in glucose detection.
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SENSORS AND ACTUATORS B-CHEMICAL
·
2015
·
IF 4.097
He Mei,Wenqin Wu,Beibei Yu,Huimin Wu,Shengfu Wang,Qinghua Xia
Fe@Pt core–shell nanoparticles were synthetized by spontaneous replacement reaction, using Vulcan XC-72 carbon as support. The physical properties of the obtained Fe@Pt/C nanocomposites were characterized by X-ray diffraction, transmission electron microscopy and X-ray photoelectron spectroscopy, and the electrocatalytic performances of the Fe@Pt/C were evaluated by cyclic voltammetry and chronoamperometry . Compared with the Pt/C, the Fe@Pt/C exhibited preferable electrocatalytic activity towards the reduction of hydrogen peroxide, and the oxidation of glucose and formaldehyde. Amperometric sensing of hydrogen peroxide was linear to its concentration in the range from 2.5 μM to 41.605 mM, with a detection limit of 750 nM (S/N = 3) and a sensitivity of 218.97 μA mM −1 cm −2 . At the same time, the sensor based on Fe@Pt/C showed a linear response range of 1–16 mM glucose, and of 12.5 μM–15.4 mM formaldehyde, with high sensitivities of 11.75 μA mM −1 cm −2 and 40.18 μA mM −1 cm −2 , respectively.
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高影响因子
Journal of Materials Chemistry A
·
2014
·Vol. 2
·期 25
·9559-9565
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IF 0
Fei Xue,Zihui Meng,Fengyan Wang,Qiuhong Wang,Min Xue,Zhibin Xu
A novel 2-D photonic crystal (PC) sensing material for the visual detection of glucose with high selectivity at a physiological ionic strength (150 mM) is developed. A monolayer polystyrene crystalline colloidal array (CCA) is embedded in a phenylboronic acid (PBA) functionalized hydrogel film to diffract light to sensitively report on the hydrogel surface area. This 2-D PC sensor is superior to the previously reported 3-D PC sensors due to its fast preparation and simple detection. The binding of glucose would increase the cross-linking of the hydrogel that could shrink the hydrogel to increase the Debye diffraction ring diameter. At a physiological ionic strength of 150 mM, the 2-D PC sensor exhibits significant sensitivity for glucose across the entire human physiological glucose range. Additionally, the 2-D PC sensor shows high selectivity for glucose rather than other sugars (fructose and galactose). The diffraction color change of the 2-D PC sensor can be observed. For validation, the prepared 2-D PC hydrogel sensor is applied for the sensing of glucose in the artificial tear fluid.
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International Journal of Chemical Engineering
·
2014
·
IF 0
Hu Li,Qiuyun Zhang,Song Yang
A series of SO3H-functionalized polymers were prepared and employed as heterogeneous catalysts for one-pot transformation of fructose into 5-ethoxymethylfurfural (EMF) that is considered to be one of potential liquid biofuels. A high EMF yield of 72.8% could be obtained at 110°C for 10 h, and the polymeric acid catalysts could be recycled for five times without significant loss of catalytic performance.
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International Journal of Chemical Engineering
·
2014
·
IF 0
Hu Li,Song Yang
L-Proline derived ionic liquids (ILs) used as both solvent and catalyst were efficient for transformation of fructose and sucrose to 5-hydroxymethylfurfural (HMF) in the presence of water. Response surface methodology (RSM) was employed to optimize fructose dehydration process, and a maximum HMF yield of 73.6% could be obtained at 90°C after 50 min. The recycling of the IL exhibited an almost constant activity during five successive trials, and a possible reaction mechanism for the dehydration of fructose to HMF was proposed.
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Biomass Conversion and Biorefinery
·
2013
·Vol. 4
·期 1
·59-66
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IF 0
Li Hu,Zhang Qiuyun,Liu Jian,Liu Xiaofang,Chang Fei,Liu Yancai,Xue Wei,Yang Song
ZrMo mixed oxides modified by a series of low-cost monofunctional carboxylic acids including stearic acid, palmitic acid, myristic acid, and lauric acid were prepared and were characterized using TG analysis, XRD, FT-IR, NH 3 -TPD, and SEM techniques. These strong solid acids were evaluated as heterogeneous catalysts with porous property for the conversion of carbohydrates to 5-hydroxymethylfurfural (HMF) by oil heating rather than using microwave heating, in the aim of facilitating the industrial feasibility of this catalytic process and discussing the relation between surface acidity and reactivity in carbohydrates to HMF conversion. Under the optimal reaction conditions, moderate yields of HMF could be achieved from fructose, glucose, sucrose, and cellulose, and the strong solid catalysts can be recycled for seven times with no significant loss of activity.
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GREEN CHEMISTRY
·
2013
·Vol. 15
·期 10
·2895-2903
·
IF 6.828
Ruliang Liu,Jinzhu Chen,Xing Huang,Limin Chen,Longlong Ma,Xinjun Li
A series of sulfonic acid-functionalized carbon materials (C–SO3H), including poly(p-styrenesulfonic acid)-grafted carbon nanotubes (CNT-PSSA), poly(p-styrenesulfonic acid)-grafted carbon nanofibers (CNF-PSSA), benzenesulfonic acid-grafted CMK-5 (CMK-5-BSA), and benzenesulfonic acid-grafted carbon nanotubes (CNT-BSA), have been studied for fructose dehydration to 5-hydroxymethylfurfural (HMF) and fructose alcoholysis to alkyl levulinate. A study for optimizing the reaction conditions such as the catalyst loading, the reaction time, and the temperature has been performed. Under the optimal conditions, high HMF and ethyl levulinate yields of up to 89% and 86%, respectively, are obtained. The catalytic activities of C–SO3H for the conversions of fructose into both HMF and ethyl levulinate follow the order of their acid strength. The relationship between the catalytic activity and acid density of C–SO3H shows a linear correspondence in the fructose dehydration to HMF. The facile separation, ease of recovery, and high thermal stability make the developed C–SO3H efficient and environment-friendly catalytic materials for transforming biomass carbohydrate into fine chemicals.
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高影响因子
BIORESOURCE TECHNOLOGY
·
2013
·
IF 4.75
Hu Li,Qiuyun Zhang,Xiaofang Liu,Fei Chang,Yuping Zhang,Wei Xue,Song Yang
A series of functional polymeric ionic liquids (FPILs) were prepared by coupling of SO 3 H-functionalized polymeric ionic liquids with different counterpart anions containing or excluding CrCl 3 ·6H 2 O, and characterized by SEM, FT-IR, XRD, NH 3 -TPD, TG, melting point, ICP-AES, and TEM. The catalytic activity of the prepared solid FPILs was investigated for the conversion of biomass including fructose, glucose and cellulose into 5-hydroxymethylfurfural (HMF) with the presence of DMSO-mediated solvents, successively producing moderate to excellent yields of HMF under atmospheric pressure. The FPILs catalysts developed in this study present improved performance on fructose-to-HMF conversion over other solid catalysts, such as functional ionic liquids supported by silica, metal oxides and strong acid ion exchange resin catalysts, and can be very easily recycled at least five times without significant loss of activity. In addition, a kinetic analysis was carried out to illustrate the formation of HMF.
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PubMed
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