查找使用阿拉丁产品的科研文献

Mesoporous ZSM-5 Zeolite-Supported Ru Nanoparticles as Highly Efficient Catalysts for Upgrading Phenolic Biomolecules

Liang Wang,Jian Zhang,Xianfeng Yi,Anmin Zheng,Feng Deng,Chunyu Chen,Yanyan Ji,Fujian Liu,Xiangju Meng,Feng-Shou Xiao

Zeolite-based catalysts have been widely used in the conversion of biomass recently, but the catalytic yields of the desired products are strongly limited by the relatively small micropores of zeolite. Here, we reported a hierarchically porous ZSM-5 zeolite with micropore and b-axis-aligned mesopore-supported Ru nanoparticles (Ru/HZSM-5-OM) that are highly efficient for the hydrodeoxygenation of both small and bulky phenolic biomolecules to the corresponding alkanes. Compared with the conventional ZSM-5 zeolite-supported Ru catalyst, the high catalytic activities and alkane selectivities over Ru/HZSM-5-OM are attributed to the abundant exposed acidic sites in HZSM-5-OM with open mesopores. This feature is potentially important for future phenolic bio-oil upgrading.

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.

Preparation of modified MFI (ZSM-5 and silicalite-1) zeolites for potassium extraction from seawater

Rongjie Ling,Wu Chen,Jin Hou

Modified nanosized MFI (ZSM-5 and silicalite-1) zeolites were successfully synthesized by a hydrothermal method using aluminum isopropoxide and tetraethylorthosilicate as the raw materials. The synthetic zeolites were characterized by X-ray diffraction, energy dispersion spectroscopy, and scanning electron microscopy. The ZSM-5 and silicalite-1 zeolites exhibited ellipse-like and cubic columns, respectively. The K + ion-exchange equilibrium and ion-exchange capacity of the synthetic zeolites in seawater were investigated. The K + ion-exchange of synthetic zeolites was rapid and reached an ion-exchange balance in approximately 20   min. The K + ion-exchange capacity of ZSM-5 and silicalite-1 in seawater was 56.7 and 48.7   mg/g, respectively. The synthetic zeolites have high selectivity toward K + , and therefore, they can be used to selectively extract potassium from seawater.

Synthesis of Renewable Triketones, Diketones, and Jet-Fuel Range Cycloalkanes with 5-Hydroxymethylfurfural and Ketones

Shanshan Li,Fang Chen,Ning Li,Wentao Wang,Xueru Sheng,Aiqin Wang,Yu Cong,Xiaodong Wang,Tao Zhang

Graphical Green triketones : Renewable C 9 –C 12 triketones with repeating [COCH 2 CH 2 ] units are synthesized in high carbon yields (ca. 90 %) over a cost-effective and reusable Au/TiO 2 catalyst. The triketones as obtained can be used as feedstocks in the production of conducting or semi-conducting polymers. Furthermore, they can also be converted to diketones or jet-fuel range branched cycloalkanes with high densities and low freezing points. A series of renewable C 9 –C 12 triketones with repeating [COCH 2 CH 2 ] units were synthesized in high carbon yields (ca. 90 %) by the aqueous-phase hydrogenation of the aldol-condensation products of 5-hydroxylmethylfurfural (HMF) and ketones over an Au/TiO 2 catalyst. Compared with the reported routes, this new route has many advantages such as being environmentally friendly, having fewer steps, using a cheaper and reusable catalyst, etc. The triketones as obtained can be used as feedstocks in the production of conducting or semi-conducting polymers. Through a solvent-free intramolecular aldol condensation over solid-base catalysts, the triketones were selectively converted to diketones, which can be used as intermediates in the synthesis of useful chemicals or polymers. As another application, the tri- and diketones can also be utilized as precursors for the synthesis of jet-fuel range branched cycloalkanes with low freezing points (224–248 K) and high densities (ca. 0.81 g mL −1 ).

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).

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

Synthesis of ZSM-5 with the silica source from industrial hexafluorosilicic acid as transalkylation catalyst

Fang Jin,Xianqiao Wang,Tieliang Liu,Linbo Xiao,Ming Yuan,Yangchun Fan

A new effective process to improve the utilization of industrial fluorosilicic acid of phosphate fertilizer by-product has been investigated to comprehensive application of the silicon and fluorine source. Two-step ammoniation was applied to recover high-quality silica. The recovered silica can be used to hydrothermal synthesize ZSM-5 zeolite without impurity phase contamination, which was confirmed by XRD, TG, SEM, BET and EDS characteristic techniques. It was found that with the increase of SiO 2 /Al 2 O 3 ratio and the extension of reaction time, the crystal type transform from the orthorhombic to the monoclinic phase. The impurity fluorine content of the recovered SiO 2 from H 2 SiF 6 has great influence on the hydrothermal process for ZSM-5 crystal structure formation. Moreover, the increase of fluorine ions content in the hydrothermal process can control the crystal morphology and size of synthesized ZSM-5. Catalytic properties of synthesized HZSM-5 with different SiO 2 /Al 2 O 3 ratio in transalkylation of toluene and 1,2,4-trimethylbenzene show good and stable catalytic performance. The ZSM-5 synthesized with recovered silica source exhibits similar catalyst life as the performance of small particle size HZSM-5, because the ZSM-5 synthesized with the silica source from industrial hexafluorosilicic acid prefers a thin disk crystal along the b axis direction, which shortens the diffusion distance of generated products.

Facet Effect of Single-Crystalline Pd Nanocrystals for Aerobic Oxidation of 5-Hydroxymethyl-2-furfural

Da Lei,Kai Yu,Meng-Ru Li,Yuling Wang,Qi Wang,Tong Liu,Pengkun Liu,Lan-Lan Lou,Guichang Wang,Shuangxi Liu

Single-crystalline Pd nanocrystals enclosed by {111} or {100} facets with controllable sizes were synthesized and originally employed as catalysts in the aerobic oxidation of 5-hydroxymethyl-2-furfural (HMF). The experimental results indicated that the particle size and exposed facet of Pd nanocrystals could obviously influence their catalytic performance. The size-dependent effect of Pd nanocrystals in this reaction could only be derived from the different Pd dispersions. Therefore, the facet effect of Pd nanocrystals was first investigated in this work through experimental and theoretical approaches. It was found that Pd-NOs enclosed by {111} facets were more efficient than Pd-NCs enclosed by {100} facets for the aerobic oxidation of HMF, especially for the oxidation step from 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) toward 5-formyl-2-furancarboxylic acid (FFCA). The TOF value of Pd-NOs(6 nm) was 2.6 times as high as that of Pd-NCs(7 nm) and 5.2 times higher than that of commercial Pd/C catalyst for HMF oxidation. Through density functional theory (DFT) calculations, the notably enhanced catalytic performance of Pd-NOs could be mainly attributed to the lower energy barrier in the alcohol oxidation step (from HMFCA to FFCA) and higher selectivity for O2 hydrogenation to produce peroxide.

Conversion of Eucalyptus Cellulose into 5-Hydroxymethylfurfural Using Lewis Acid Catalyst in Biphasic Solvent System

Wei W. Q.,Wu S. B.

Conversion of eucalyptus cellulose into 5-hydroxymethylfurfural (5-HMF) by using Lewis acid catalyst in biphasic system was investigated in this study. The results show that the tetrahydrofuran/water biphasic system was more conducive to convert the eucalyptus cellulose into 5-HMF comparing to the single aqueous system. InCl 3 , a water-compatible Lewis acid, has the best catalytic effect. The highest yield of 5-HMF from eucalyptus cellulose is up to 45.05 mol%, which is a slight higher than that from microcrystalline cellulose. It can be ascribed to the lower crystallinity of isolated eucalyptus cellulose. The optimum conditions for catalytic conversion of eucalyptus cellulose into 5-HMF are at 200 °C for 2 h with 10 % InCl 3 dosage. Additionally, the effect of recycling the whole biphasic system which contains InCl 3 , NaCl, H 2 O and THF indicated that the 5-HMF yield was gradually decreased as the cycle times increased, the possible reason could be due to the loss of partial InCl 3 catalyst during the separation and distillation process.

Producing pyridines via thermo-catalytic conversion and ammonization of glycerol over nano-sized HZSM-5

Lujiang Xu,Qian Yao,Ying Zhang,Yao Fu

In this study, nano-sized HZSM-5 catalysts with different Si/Al ratios were synthesized and employed for producing pyridines from glycerol via a thermo-catalytic conversion and ammonization (TCC-A) process. The catalytic performance of micro-sized HZSM-5 and nano-sized HZSM-5 was studied firstly. The nano-sized HZSM-5 showed better catalytic performance in pyridine production in the TCC-A process due to its smaller particle size. When the nano-sized HZSM-5 (Si/Al = 25) served as the catalyst, and the reaction temperature was about 550 °C with the weight hourly space velocity of glycerol to catalyst at 1 h−1 and the ammonia to glycerol ratio at 12 : 1, the highest yield of pyridines was up to 42.1%, which was much higher than that when using micro-sized HZSM-5 (35.6%) reported before. In addition, nano-sized HZSM-5 also showed a better catalytic performance than micro-sized HZSM-5 in the catalytic conversion of bio-derived furans to produce indoles. After five reaction/regeneration cycles, the catalytic performance of nano-sized HZSM-5 slightly decreased compared with the first run, but was still higher than that of micro-sized HZSM-5.

Synthesis of Flower-Like Hybrid BiOI/HZSM-5 Composites with High Visible-Light Photocatalytic Activity

Wei Li,Gang Ni,Jing Li,Ying Han

BiOI/HZSM-5 composites were synthesized via a facile and environmentally-benign hydrothermal method. The crystalline structures and morphologies of the powder have been characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The photocatalytic activity of samples was tested for degradation of methylene blue (MB) and Rhodamine B (RhB) dye under simulated solar light irradiation. The degradation rate of MB and RhB by BiOI/HZSM-5 composite photocatalysts respective reach 99.6% and 98.6% under visible light irradiation, BiOI/HZSM-5 exhibited the highest photocatalytic performance when compared with pure BiOI.