CELLULOSE
·
2019
·Vol. 26
·期 17
·9135-9147
·
IF 3.917
Zhou Shengqiang,Yang Xiaomei,Zhang Yali,Jiang Lingyun,Zhou Lipeng,Lu Tianliang,Su Yunlai
Abstract One-pot conversion of cellulose to valued-added platform chemicals such as alkyl levulinate is a promising and challenging process of biomass utilization due to the insolubility of cellulose in alcohol. In this work, commercial heteropoly acid combined with postsynthesized Sn-Beta zeolite was employed to transform cellulose to methyl levulinate (MLE) in one pot. The synergistic catalysis of the homogeneous strong Brønsted (B) acid and the solid strong Lewis (L) acid can effectively realize the depolymerization of solid cellulose and the subsequent isomerization, dehydration and hydration steps to MLE. 55% and 62% of MLE yields were obtained from α-cellulose and microcrystalline cellulose, respectively, at 160 °C for 10 h. Various carbohydrates besides cellulose can also be efficiently converted to MLE in high yields over the bifunctional catalyst system. The effects of the amount of B acid and L acid, the reaction temperature and time and the amount of cellulose on the production of MLE were investigated in detail. Finally, the reaction pathway of cellulose to MLE was revealed. Recyclability tests indicated that the binary catalyst can be reused without decrease of catalytic activity. Graphic abstract
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CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2019
·Vol. 36
·期 5
·865-869
·
IF 1.071
Yu Fengli,Chi Yujie,Gao Chong,Chen Ruirui,Xie Congxia,Yu Shitao
A series of amino-acid-based ionic liquids was synthesized via one-step protonation of the corresponding L -amino acid by utilizing an array of proton sources. The catalytic activity of the amino-acid-based ionic liquids for the Baeyer-Villiger oxidation of cyclic ketones was investigated using cyclopentanone as a model cycloketone. The proline-based ionic liquid [ProH]CF 3 SO 3 was shown to exhibit the best catalytic activity. The reaction condition was optimized to give the following reagent ratio of n (cyclopentanone): n (catalyst): n (H 2 O 2 )=1:0.06:4, 60 °C and 6 h. Under the optimum conditions, the conversion of cyclopentanone was 96.57% and the selectivity for δ-valerolactone was 73.01%. The catalytic activity was shown to be constant after 4 cycles. A simple treatment was allowed for the recover and the reuse of [ProH]CF 3 SO 3 . The successful utilization of [ProH]CF 3 SO 3 to catalyze a host of cyclic ketones via Baeyer-Villiger oxidation clearly demonstrated the capacity of [ProH]CF 3 SO 3 to tolerate variation in the substrate.
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JOM
·
2019
·Vol. 71
·期 12
·4547-4555
·
IF 2.305
Chen Yan,Liu Yi,Chen Zhengshou,Shi Qian,Gao Junkai,Ding Han,Tang Xi,Liu Yu
Novel mesoporous carbon microspheres (MCMS), which exhibited a large surface area and were developed by the pyrolysis of polydopamine microspheres (PDAMS), were used as a supporting material for polyethylene glycol (PEG) to prepare a new type of efficient form-stable phase-change material (MCMS-PEG). Using a simple vacuum impregnation strategy, the preparation of polydopamine microspheres via a biomimetic method was facile, simple and environmentally friendly. Characterization of MCMS-PEG was performed by scanning electron microscopy (SEM), x-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). The results suggested that MCMS-PEG possessed high latent heats of 112.08 J/g during the melting process and 107.34 J/g during the solidification process. Additionally, MCMS-PEG presented an enhanced thermal conductivity and excellent thermal stability. Therefore, the novel mesoporous carbon microspheres developed in this study could be used as efficient supports for the preparation of shape-stabilized phase-change materials.
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AAPS PHARMSCITECH
·
2019
·Vol. 20
·期 8
·1-13
·
IF 2.608
Qu Yang,Lai Wen-Long,Xin Yuan-Rong,Zhu Fei-Qin,Zhu Yuan,Wang Li,Ding Yue-ping,Xu Ying,Liu Hong-Fei
To enhance efficiency, convenience, and safety of Parkinson’s disease (PD) treatment for geriatric patients, an advanced suspension of Levodopa/Benserazide hydrochloride (LD/BH) has been prepared by cation-exchange resin and used to synchronize sustained release of LD and BH by optimizing coating parameters and prescription. For the purpose, LD and BH were immobilized on the surface of cation-exchange resin, respectively. Based on HPLC results, the cation-exchange resin showed high loading capacity. The studies on drug loading mechanism indicated that both drugs were immobilized by electrostatic interaction rather than physical adsorption. After PEG modification, pretreated drug-resin complexes were coated by emulsion–solvent evaporation method. In order to control drug release in a sustained manner, coating parameters of drug-resin microcapsules were optimized respectively by single-factor analysis. Further, coating prescription of the microcapsules was optimized to synchronize sustained release of LD and BH in vitro by orthogonal design. Utilizing optimal LD-resin microcapsules and BH-resin microcapsules, LD/BH suspension, containing both of them, was prepared by an optimal formulation and characterized by accelerated test and pharmacokinetic study in vivo . The accelerated test confirmed high stability of LD/BH suspension. According to pharmacokinetic results in vivo , in contrast with LD/BH commercial tablets, LD/BH suspensions did not only synchronize sustained release of both drugs but also show good bioequivalence. As LD/BH sustained release suspension can synchronize sustained release of multiple active ingredients by oral administration, the suspension presents promising oral dosage forms for geriatric patients with PD.
An advanced Levodopa/Benserazide hydrochloride (LD/BH) suspension, prepared by cation-exchange resin and optimized microencapsulation, synchronizes sustained releases of LD and BH in vivo to benefit Parkinson’s disease treatment for geriatric patients.
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PubMed
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2019
·Vol. 26
·期 32
·33269-33280
·
IF 2.914
Li Ting,Huang Pengwei,Liao Taiwan,Guo Jia,Yu Xiang,Han Boping,Peng Liang,Zhu Yi,Zhang Yuanming
In this paper, a new magnetic polymer–supported phosphate adsorbent MPVC-EDA-Ce was prepared by loading cerium (hydr)oxides onto ethylenediamine-functionalized polyvinyl chloride for the first time. MPVC-EDA-Ce showed excellent adsorption performances towards phosphate and easy recovery. The adsorption isotherm and kinetics of MPVC-EDA-Ce followed Langmuir monolayer model and the pseudo-second-order model, respectively. The pH results demonstrated that the MPVC-EDA-Ce could effectively remove phosphate in a wide range of pH with insignificant cerium leaching. Furthermore, analyses on adsorption mechanism and effect of competing anions demonstrated the formation of strong inner-sphere complexation between cerium (hydr)oxides and phosphate, which was a selective adsorption process, while positively charged quaternary ammonium groups adsorbed phosphate via relatively weak electrostatic attraction which was a non-selective adsorption process. The study provided a good reference to design novel phosphate adsorbents with two even more functional adsorption sites and a deep insight to investigate the adsorption mechanism towards phosphate.
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Scientific Reports
·
2019
·Vol. 9
·期 1
·1-10
·
IF 4.011
Liu Jiakuan,Fang Tian,Li Meiqian,Song Yuting,Li Junzun,Xue Zesheng,Li Jiaxuan,Bu Dandan,Liu Wei,Zeng Qinghe,Zhang Yidan,Yun Shifeng,Huang Ruimin,Yan Jun
Benign prostatic hyperplasia (BPH) is one of the most common diseases in the urinary system of elderly men. Pao extract is an herbal preparation of the bark of the Amazon rainforest tree Pao Pereira ( Geissospermum vellosii ), which was reported to inhibit prostate cancer cell proliferation. Herein we investigated the therapeutic potential of Pao extract against BPH development in a testosterone-induced BPH rat model. The administration of testosterone induced the prostate enlargement, compared with the sham operated group with vehicle treatment. The BPH/Pao group showed reduced prostate weight comparable with BPH/finasteride group. Notably, Pao treatment did not significantly reduce body weights and sperm number of rats, compared with the control group. Furthermore, Pao extract treatment reduced the proliferative index in prostate glands and testosterone-induced expression levels of AR, as well as androgen-associated proteins such as SRD5A1 and PSA. Moreover, Pao extract and its active component, flavopereirine, induced cytotoxicity on human prostate epithelial RWPE-1 cells in a dose- and time- dependent manner with G2/M arrest. Consistently, Pao extract and flavopereirine suppressed the expression levels of SRD5A1, AR and PSA, respectively. Together, these data demonstrated that Pao extract suppresses testosterone-induced BPH development through inhibiting AR activity and expression, and suggested that Pao extract may be a promising and relative safe agent for BPH.
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PubMed
高影响因子
NPG Asia Materials
·
2019
·Vol. 11
·期 1
·1-12
·
IF 8.052
Su Danni,Zhang Xiaomeng,Wu Aiping,Yan Haijing,Liu Ziyi,Wang Lei,Tian Chungui,Fu Honggang
Driving the electrocatalytic hydrogen evolution reaction (HER) with solar-energy cells is considered a green and sustainable way to produce H 2 . Herein, CoO-Mo 2 N hollow heterojunctions were designed for effective HER based on the combined virtues of the hollow structure and heterojunctions. The hollow CoMoO 4 -Co(OH) 2 precursor was first synthesized via the reaction of Co 2+ from ZIF-67 with MoO 4 2− and OH − in a Na 2 MoO 4 solution. A series of experiments indicate the formation of the hollow Co-Mo-O precursor followed a mechanism analogous to the nanoscale “Kirkendall Effect”. After heating in NH 3 , the CoO-Mo 2 N hollow heterostructure was obtained. The Mo species in the precursor played an important role in maintaining the morphology under nitridation treatment. The hollow structure is favorable for contact and diffusion of electrolyte with (in) catalysts, while the CoO in CoO-Mo 2 N is favorable for the dissociation of water. Both promote the HER. Under optimized conditions, the hollow catalyst exhibited good HER performance with an overpotential of 65 mV at 10 mA cm −2 in 1 M KOH. The performance is better than that of many nonprecious metal-based catalysts. An electrolyzer composed of CoO-Mo 2 N heterojunctions as the cathode and NiFe-LDH as the anode can be driven by a solar cell to achieve effective overall water splitting. The adjudication of MOFs makes the route promising for the design of robust catalysts for advanced application.
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MICROCHIMICA ACTA
·
2019
·Vol. 187
·期 1
·1-8
·
IF 5.479
Zhang Chun-Xia,Gao Yan-Cai,Wang Chong,Yu Xu,Li Hong-Wei,Wu Yuqing
The fluorescence of adenosine monophosphate-capped bimetallic gold and silver nanoclusters (type AuAgNC@AMP) is strongly enhanced and blue shifted in the presence of Al(III). As confirmed by transmission electron microscopy, the AuAgNC nanodots are converted to larger assembled spheres of type AuAgNC-Al(III). The fluorescence enhancement is attributed to aggregation-induced emission enhancement (AIEE). The fluorescence of the AuAgNC-Al(III) assembly (with excitation and emission maxima at 340 and 540 nm) is quenched by cysteine (Cys). The effect was applied to the fluorometric determination of Cys. The assay works in the 1.0 to 16.0 μM Cys concentration range and has a 50 nM limit of detection. The method was successfully applied to analyze Cys-spiked mineral waters and serum. The quenching mechanism is explored in depth. It is attributed to the partial replacement of AMP by Cys at the surface of the AuAgNC and alteration of the assembly structure from large spherical particles to a strip shape.
Schematic representation of the fluorescence enhancement of bimetallic nanoclusters capped with adenosine monophosphate by using Al(III), and its application in selective and sensitive determination of cysteine via ligand replacement and reassembly.
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CELLULOSE
·
2019
·Vol. 26
·期 18
·9889-9899
·
IF 3.917
Tian Peixiu,Liu Mingsheng,Wan Caiyan,Zhang Guangxian,Zhang Fengxiu
Abstract A flame retardant ammonium salt of diethylene glycol phosphonate (ADGP) is synthesized using low-cost materials (diethylene glycol, phosphoric acid, and urea). The flame retardant is grafted on the cotton fabrics via P–O–C covalent bonds. The structure of the flame retardant is characterized by nuclear magnetic resonance (NMR) and Fourier transform infrared (FT-IR). The combustion performance of the treated and untreated cotton fabrics is evaluated based on vertical flammability, limiting oxygen index (LOI), and cone calorimetry. As the concentration of the flame-retardant ADGP increased, the cotton fabric treated with 40% ADGP exhibited an LOI of 43.7% and superior fire resistance, whereas physiological comfort showed a decrease. Scanning electron microscopy, energy dispersive X-ray spectroscopy, and X-ray diffraction were used to characterize the surface morphology, chemical composition, and crystal structure of the control and treated cotton fabrics. The thermal stability of the treated and untreated cotton fabrics is determined by thermogravimetric analysis. The results indicated that the treated cotton showed superior flame retardancy. Graphic abstract
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JOURNAL OF NANOPARTICLE RESEARCH
·
2020
·Vol. 22
·期 1
·1-15
·
IF 2.132
Ding XiangYu,Cao Qi,Zhu Sheng,Xu Qunjie,Min Yulin
A bio-inspired strategy has been proposed to synthesize a unique kind of 3D porous cobalt oxide and carbon nanosheet composite materials (PCN@Co 3 O 4 ), as a lithium-ion battery anode material. In this work, turnip has been chosen as a two-dimensional nanobiomass carbon substrate and choosing cobalt salt as the metal precursor by using plant cell suction phenomenon of dehydration to prepare PCN@Co 3 O 4 . When PCN@Co 3 O 4 is applied for the anode material for lithium-ion batteries, it delivers ultrahigh reversible capacity and excellent electrochemical performance. After 100 cycles, PCN@Co 3 O 4 has a reversible specific capacity of 1004.2 mA h g −1 at a current density of 100 mA g −1 and a reversible capacity of about 923.7 mA h g −1 after 400 cycles even at a high current density of 1000 mA g −1 . Furthermore, it also exhibits a high rate capability, which can be stabilized at about 1151, 939.7, 771.4, and 631.5 mA h g −1 for every 10 successive cycles when increasing the current density to 100, 500, 1000, and 1500 mA g −1 , respectively. And a satisfactory-specific capacity can be recovered to the original value (about 1150 mA h g −1 ) at a current density of 100 mA g −1 after 60 discharge/charge cycles.
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Journal of Central South University
·
2020
·Vol. 26
·期 11
·2953-2960
·
IF 1.249
Liu Piao,He Wen-qiang,Lu An-xian
Finer nanoplates of silver are prepared by self-assembly on the surface of graphene, and the low-temperature sintered high conductivity ink containing the silver nanoplates is prepared. Most importantly, graphene is added to the solution before the chemical reduction reaction occurs. Firstly, it is found that silver nanoplates have self-assembly phenomenon on the surface of graphene. Secondly, the Ag nano hexagonal platelets (AgNHPs) with small particle sizes (10 nm), narrow distribution and good dispersion are prepared. Especially, smaller sizes (10 nm) and narrower particle size distribution of AgNHPs particles can be easily controlled by using this process. Finally, the conductivity of the ink is excellent. For example, when the printed patterns were sintering at 150 °C, the resistivity of the ink(GE: 0.15 g/L) reached the minimum value of 2.2×10 −6 Ω·cm. And the resistivity value was 3.7×10 −6 Qcm, when it was sintered at 100 °C for 30 min. The conductive ink prepared can be used for the field of printing electronics as ink-jet printing ink.
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JOURNAL OF ELECTRONIC MATERIALS
·
2020
·Vol. 49
·期 3
·2058-2065
·
IF 1.774
Lan Ye,Chen Dajun
Porous silica-based anode materials with high theoretical specific capacity and abundant reserves have attracted popular attention for application in lithium ion batteries (LIBs). However, poor electrochemical conductivity and mechanical performance hinder the development of silica-based anode materials. In this work, attapulgite/multi-walled carbon nanotube (AT/CNT) composite anode materials were prepared. The structural features of AT/CNT composite aerogels were characterized by field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS), x-ray diffraction (XRD) and Brunauer–Emmett–Teller (BET). because of the excellent conductivity and porous pathways of AT/CNT anode material, the reversible specific capacity of AT/CNTs containing 0.5 wt.% CNTs (AT-0.5) with a mass loading of 0.67 mg cm −2 was 303.6 mAh g −1 at 0.1 A g −1 after 50 cycles, and a coulombic efficiency of AT-0.5 was 99.1%. The green LEDs were lit by the assembled battery of AT-0.5. The electrochemical results demonstrated that AT/CNT anode materials possessed practical application values for energy storage. Moreover, the preparation method of AT/CNT anode materials is efficient and environmentally friendly.
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