查找使用阿拉丁产品的科研文献

Morphologically Cross-Shaped Ru/HZSM-5 Catalyzes Tandem Hydrogenolysis of Guaiacol to Benzene in Water

Zhaoxia Zheng,Zhicheng Luo,Chen Zhao

Graphical Taking the cross : Morphologically cross-shaped HZSM-5 loaded Ru nanoparticles demonstrate high activity (rate: 7.8 g g −1 h −1 ) in the selective hydrogenolysis of guaiacol to benzene in water with a nearly quantitative yield accompanied with high durability. Hydrogenolysis of C−O bonds is an important tool for synthesis of valuable fuels and chemicals from biomass. In this contribution, we report that morphologically cross-shaped HZSM-5-loaded Ru nanoparticles have demonstrated high activity in the selective hydrogenolysis of guaiacol to benzene in water with 97 % yield and a rate of 7.8 g g −1 h −1 accompanied with high durability. N 2 sorption analysis showed that Ru/HZSM-5 (cross-shaped) had a large mesoporous surface area and pore volume for loading small and uniform Ru nanoparticles, as confirmed by TEM images. The stronger interaction of Ru and cross-shaped HZSM-5 was simultaneously confirmed by a higher hydrogen reduction temperature of RuO 2 on calcined Ru/HZSM-5, a blueshift of Ru δ+ -(CO) n , Ru δ+ -(CO), and Ru 0 -(CO) species in the IR spectra of adsorbed CO, and a higher Ru 3d 5/2 binding energy in X-ray photoelectron spectroscopy measurements. The reaction constant in guaiacol hydrogenolysis to phenol over cross-shaped Ru/HZSM-5 (0.051 min −1 ) was 3–4 times higher than that on spherical and cuboid Ru/HZSM-5 (0.012–0.029 min −1 ) at identical conditions, attributed to the remarkable hydrogenolysis catalytic capability of Ru nanoparticles on cross-shaped HZSM-5. In addition, adsorption of guaiacol and hydrogen was more substantial on cross-shaped Ru/HZSM-5, as evidenced by of IR and mass spectroscopy, respectively. The higher adsorption of guaiacol is attributed to the abundant Lewis acid sites on cross-shaped Ru/HZSM-5, as the Al−OH enriched Lewis acid sites favor the adsorption of oxygen-containing guaiacol. The higher rate constant in the primary step, together with the adsorbed high concentrated reactant and hydrogen (with nearly first-order reaction kinetics) on cross-shaped Ru/HZSM-5, facilitates the overall tandem reaction, leading to an excellent hydrogenolysis catalyst working at hydrothermal conditions for biomass conversion.

Synthesis of different structured FePO4 for the enhanced conversion of methyl cellulose to 5-hydroxymethylfurfural

Yong Liu,Zili Li,Yaohui You,Xiaogang Zheng,Jing Wen

FePO4 catalysts with branch-like, flower-like, and spherical morphologies were synthesized for the conversion of methyl cellulose to 5-hydroxymethylfurfural (5-HMF) via a hydrothermal route. The molar ratio of Fe3+ and H2PO4− ions in the reaction system played a crucial role in the morphology of FePO4. Compared with flower-like, spherical and amorphous FePO4, branch-like FePO4 presented a better catalytic performance in the cellulose conversion and 5-HMF yield. The branch-like FePO4 retained a branch structure after recycling five times in the bi-phasic reaction process. The insolubility of low temperature and partial dissolution of elevated temperature were responsible for the excellent catalytic activity of the FePO4 phase-change catalyst. The combined effect of H+ ions and iron species generated from the hydrolysis of FePO4 can be favorable for the enhanced yield of 5-HMF.

Microwave-Assisted Conversion of Fructose to 5-Hydroxymethylfurfural Using Sulfonated Porous Carbon Derived from Biomass

Qiufeng Wang,Jiaqi Hao,Zhenbo Zhao

In this study, a series of sulfonated carbon solid acid catalysts was prepared by a template method using fructose as the carbon source and zinc chloride as the catalyst and template. The reaction involving fructose dehydration to 5-hydroxymethylfurfural (5-HMF) was investigated using these catalysts with microwave assistance in dimethyl sulfoxide. The influence of different catalysts, catalyst amount, microwave power, fructose content, and reaction temperature, as well as the reusability of the catalyst, were investigated. The prepared catalysts were characterised by X-ray diffraction, FT-IR spectroscopy, scanning electron microscopy, nitrogen adsorption–desorption measurement, and temperature-programmed desorption of ammonia gas, and the total numbers of surface acid sites of these carbon-based solid acid catalysts were analysed by chemical adsorption–desorption of ammonia along with the standard curve for ammonia. The results revealed that the C2-SO3H catalyst exhibited the best activity. A 5-HMF yield of 87 % and fructose conversion of 99 % were achieved at 170°C in DMSO after 3 min. The microwave-assisted synthetic strategy was advantageous compared with the traditional method because this approach could shorten the total reaction time.

Experimental and theoretical studies on imidazolium ionic liquid-promoted conversion of fructose to 5-hydroxymethylfurfural

Yu-Nong Li,Jin-Quan Wang,Liang-Nian He,Zhen-Zhen Yang,An-Hua Liu,Bing Yu,Chao-Ran Luan

A combined experimental and computational study on the imidazolium ionic liquid-promoted conversion of fructose to 5-hydroxymethylfurfural (HMF) was performed. In particular, 1-butyl-3-methyl-imidazolium bromide (BMImBr) was found to be unexpectedly effective for conversion of fructose into HMF without utilizing any other additive or catalyst. Under the optimized conditions, nearly 100% conversion of fructose with a 95% yield of HMF could be obtained. In addition, BMImBr could be easily recovered and reused over 6 times without significant loss of activity. This protocol represents a simple, recyclable and environmentally friendly pathway for HMF production. Furthermore, the detailed mechanism of the BMImBr-promoted conversion of fructose into HMF was also studied through an in situ FT-IR technique, NMR and density functional theory calculations, and demonstrated that the hydrogen bond interaction between BMImBr and fructose could play an important role in promoting the dehydration of fructose. This work also provides further understanding at the molecular level of the reaction process for ionic liquid-promoted conversion of fructose to HMF.

A Highly Sensitive and Selective Iron Ion Fluorescent Probe for Water-Soluble Pillar[5]Arene

Xia Tian,Jianrong Han,Wei Li,Wei Yuan,Yuting Li,Yupeng Wang,Chengbin Wang,Wei Su,Shouxin Liu

Graphical As chemosensor, a novel d -gluconamide-functionalized water-soluble pillar[5]arene ( GWP5 ) displays high sensitivity and selectivity toward Fe 3+ ions over competing metal ions, based on fluorometric and colorimetric measurements. This fluorescent probe could be applied to the detection of Fe 3+ ions in real environmental water samples and in serum samples. A novel d -gluconamide-functionalized water-soluble pillar[5]arene ( GWP5 ) was synthesized through a simple synthetic route. GWP5 showed a remarkable aggregation-induced emission (AIE) with increasing concentration. This feature served as the basis for the construction of an AIE-based sensor for fluorescence detection of Fe 3+ with high sensitivity and selectivity, with a linear relationship between luminescence quenching and Fe 3+ concentration observed from 0 to 20 µM, and a limit of detection of 7.84 × 10 −9 M. This fluorescent probe could be applied to the detection of Fe 3+ ions in real environmental water samples and in serum samples.

Constructing Co2C and ZSM-5 interface for enhanced activity in Fischer-Tropsch synthesis to olefins

Yibo Tang,Jiayin Liang,Jiabing Chen,Mengheng Wang,Xinying Liu,Xiaojun Lu

Na- and Mn-promoted Co 2 C-based catalysts have demonstrated promise for the one-step conversion of syngas to olefins via Fischer-Tropsch synthesis to olefins (FTO). However, their consistently low activity limits their industrial applications. Here, we designed a compound catalyst comprising a CoMn composite catalyst and ZSM-5 zeolite, achieving 4.9 times the activity compared to the sole Co 2 C catalyst without compromising olefin selectivity. CO– and H 2 -TPD studies, in-situ DRIFT experiment, and DFT calculation revealed that the surface acidity of ZSM-5 modulated the strong electron effect of Na, subsequently strengthening H 2 adsorption on the Co 2 C catalyst surface. The H-assisted CO dissociation was therefore promoted and the catalyst activity was boosted. Meanwhile, Co 2 C as active site was unaffected, maintaining high selectivity to olefins. Constructing an interface between Co 2 C and ZSM-5 in the compound catalyst is proven to be a successful strategy for enhancing the activity of Co 2 C-based catalysts for FTO.

Catalytic transfer hydrogenation/hydrogenolysis of 5-hydroxymethylfurfural to 2,5-dimethylfuran over Ni-Co/C catalyst

Panpan Yang,Qineng Xia,Xiaohui Liu,Yanqin Wang

Catalytic transfer hydrogenation/hydrogenolysis of 5-hydroxymethylfurfural (HMF) to valuable chemicals, 2,5-dimethylfuran (DMF), is realized over a carbon supported nickel-cobalt catalyst with formic acid as hydrogen donor. The highest DMF yield, 90.0%, is achieved at 210   °C under self-generated pressure. A reaction route involving 5-methylfurfural (5-MF) instead of 2,5-bis(hydromethyl)furan (BHMF) as an intermediate has been investigated, which is different from that when H 2 is used as hydrogen source in previous reports. The influence of the amount of formic acid is investigated on the conversion of HMF and the yield of DMF. The effectiveness of this strategy has also been used for the conversion of furfural to 2-methylfuran, another valuable chemicals.

An immobilized carboxyl containing metal-organic framework-5 stationary phase for open-tubular capillary electrochromatography

Tao Bao,Pingxiu Tang,Zhenkun Mao,Zilin Chen

A novel capillary column with metal-organic framework-5 (MOF-5) as the stationary phase was prepared for open-tubular capillary electrochromatography (OT-CEC). To grow MOF-5, the fused-silica capillary was functionalized firstly using 3-aminopropyltriethoxysilane and glutaraldehyde as covalent linkers; and then MOF-5 would be immobilized on the inner wall of COOH-terminated capillary by epitaxial growth , to produce a MOF-5-modified capillary. The successful growth of MOF-5 has been characterized and confirmed by scanning electron microscopy, X-Ray diffraction and Fourier transform infrared spectra . The influence of pH value and methanol on electroosmotic flow (EOF) of the MOF-5-modified capillary column was investigated. The EOF showed a pH-dependent from anode to cathode. The immobilization of MOF-5 improved the interactions between analytes and layer on inner wall of the capillary. Excellent separations of substituted benzenes and acidic and basic analytes were obtained on the fabricated capillary columns. The MOF-5-modified capillary columns exhibited good repeatability, with relative standard deviations for intra-day, inter-day runs and column-to-column less than 1.87%, 3.53%, and 8.49%, respectively. Our successful application of MOF-5 paved the way for introducing series of dicarboxylate-based isoreticular MOFs to OT-CEC as novel stationary phase.

Antitumor activity of electrospun polylactide nanofibers loaded with 5-fluorouracil and oxaliplatin against colorectal cancer

Jiayu Zhang,Xue Wang,Tongjun Liu,Shi Liu,Xiabin Jing

A new FRET-based ratiometric probe for fluorescence and colorimetric analyses of adenosine 5′-triphosphate

Nianqi An,Qiang Zhang,Jing Wang,Cui Liu,Luqing Shi,Lihua Liu,Ludi Deng,Yan Lu

This paper reports a new ratiometric probe for the detection of adenosine 5′-triphosphate (ATP) that is based on the binding-induced modulation of fluorescence resonance energy transfer (FRET) coupled with the aggregation-caused quenching (ACQ) sensing mechanism. The introduction of coumarin fluorophores as FRET donors into the side-chain of polythiophene (PT) as the FRET acceptor provides the ratiometric probe. Upon addition of ATP, the formation of a polymer/ATP complex leads to the conformational changes of the PT backbone from a random coil to the planar conformation and aggregation. As such, the ratiometric ATP detection can be achieved by taking advantage of spectral overlap changes to modulate the FRET efficiency from coumarin fluorophores to the PT backbone before and after the addition of ATP, coupled with ACQ. The probe exhibited a clear seesaw-type dual-emission signal change upon binding with strong affinity (Kapp = 3.12 × 104 M−1) to ATP in aqueous solution, whereas no obvious emission changes were observed with ADP, AMP or various other anions. The probe can also be utilized for naked-eye detection of ATP and real-time monitoring of the ATP hydrolysis reaction by apyrase under physiological pH conditions.

Carboxymethyl chitosan/poly(ethylene oxide) water soluble binder： Challenging application for 5 V LiNi0.5Mn1.5O4 cathode

Haoxiang Zhong,Jidian Lu,Aiqin He,Minghao Sun,Jiarong He,Lingzhi Zhang

Carboxymethyl chitosan/poly (ethylene oxide) (CCTS/PEO) composite is firstly reported as a water soluble binder for the application of 5   V LiNi 0.5 Mn 1.5 O 4 cathode in Li-ion batteries. Both CCTS and PEO show a high electrochemical oxidation potential of above 5.0   V (vs. Li/Li + ). The electrochemical performances of LiNi 0.5 Mn 1.5 O 4 (LNMO) cathodes with CCTS/PEO composite binders of different mass rates are investigated, it is found that LiNi 0.5 Mn 1.5 O 4 cathode with an optimized CCTS/PEO (85/15, w/w) composite exhibits a slightly better cycling performance than that of polyvinylidene fluoride (PVDF), retaining 81.4% capacity as compared with 79.8% for PVDF at 0.5C rate after 200 cycles. LNMO with PEO/CCTS (85/15, w/w) exhibited the better rate capability than that of PVDF. These results demonstrate that CCTS/PEO composite can be potentially used as a water-soluble binder for 5   V LNMO cathode.

Structure–Function Relationship of a Novel PR-5 Protein with Antimicrobial Activity from Soy Hulls

Chun Liu,Fenfen Cheng,Yingen Sun,Hongyu Ma,Xiaoquan Yang

An alkaline isoform of the PR-5 protein (designated GmOLPc) has been purified from soybean hulls and identified by MALDI-TOF/TOF-MS. GmOLPc effectively inhibited in vitro the growth of Phytophthora soja spore and Pseudomonas syringae pv glycinea. The antimicrobial activity of GmOLPc should be mainly ascribed to its high binding affinity with vesicles composed of DPPG, (1,3)-β-d-glucans, and weak endo-(1,3)-β-d-glucanase activity. From the 3D models, predicted by the homology modeling, GmOLPc contains an extended negatively charged cleft. The cleft was proved to be a prerequisite for endo-(1,3)-β-d-glucanase activity. Molecular docking revealed that the positioning of linear (1,3)-β-d-glucans in the cleft of GmOLPc allowed an interaction with Glu83 and Asp101 that were responsible for the hydrolytic cleavage of glucans. Interactions of GmOLPc with model membranes indicated that GmOLPc possesses good surface activity which could contribute to its antimicrobial activity, as proved by the behavior of perturbing the integrity of membranes through surface hydrophobic amino acid residues (Phe89 and Phe94).