Molecular Catalysis
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2022
·
IF 5.089
Niuniu Zhu,Manyu Zhang,Guo Qiu,Hongyu Tian,Yongguo Liu
The synthesis of platform chemical 5-hydroxymethylfurfural (5-HMF) provides favorable and efficient paths for the utilization of renewable biomass resources. In this work, highly active niobium-modified montmorillonite (Nb-Mont) catalysts were synthesized by a facile and ion-exchange method and were used for the one-pot conversion of cellobiose and sucrose to 5-HMF with optimal results. 5-HMF yield of 68.6% was obtained from cellobiose in a methyl isobutyl ketone (MIBK)/saturated salt water (SSW) biphasic solvent at 170 °C after 3 h. With sucrose as substrate in DMSO at 140 °C after 2 h, 5-HMF yield was 65.4%. The presence of Lewis and Brønsted acid sites on Nb-Mont facilitate the hydrolysis of cellobiose and sucrose and play essential roles in the subsequent isomerization of glucose monomer and the dehydration of fructose monomer. A possible reaction mechanism was proposed for the transformation of cellobiose and sucrose into 5-HMF, and the isomerization process of glucose monomer was the most critical step, confirmed by density functional theory (DFT) calculations. [NbO(OH) 2 ] + species as active sites could effectively reduce the activation energy of the isomerization process, which accelerated the synergetic proton transfer process. Nb-Mont was recycled at least four times without a prominent loss in the catalytic activity. In this study, a promising catalytic strategy was provided for heterogeneous Nb containing catalysts used in the effective synthesis of 5-HMF from carbohydrates.
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EUROPEAN JOURNAL OF INORGANIC CHEMISTRY
·
2022
·Vol. 2022
·期 24
·e202200260
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IF 2.551
Guang Xiong,Shengyang Zhou,Liping Liu,Ji Qian,Jiaxu Liu,Leping Zhao
Graphical Y/ZSM-5 composite zeolite was synthesized by an aerosol-assisted hydrothermal method including a two-step crystallization. The structure and acidity of the composite zeolite can be modulated by monitoring the synthesis conditions. Y/ZSM-5 composite zeolite was synthesized by an aerosol assisted hydrothermal method including a two-step crystallization. The aerosol technique was used to prepare the precursor of Y/ZSM-5 composite zeolite. This helped to fully utilize the amorphous silica-alumina species left in the primary crystallization solution of NaY zeolite, and to bring the two zeolites close to each other during the second crystallization step. The optimal adding sequence and synthesis conditions were investigated to reduce the amount of template and accelerate the crystallization rate. The composite zeolites were analyzed using XRD, SEM, nitrogen physical adsorption, NH 3 -TPD techniques. It was found that the acid properties can be adjusted by modulating the SiO 2 /Al 2 O 3 molar ratio of the secondary crystallization feed. The BET specific surface area of the optimal Y/ZSM-5(20) composite zeolite is 502 m 2 /g, the pyrolysis conversion rate of 1,3,5-triisopropylbenzene reaches 95.1 %, and the selectivity to benzene reaches 53.4 %.
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CERAMICS INTERNATIONAL
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2022
·
IF 5.532
Debao Liu,Zhiliang Zhou,Yiguang Wang,Baosheng Xu
The high-entropy rare earth zirconate (La 1/5 Nd 1/5 Sm 1/5 Gd 1/5 Yb 1/5 ) 2 Zr 2 O 7 porous ceramics ((5RE 1/5 ) 2 Zr 2 O 7 PCs) were prepared using a foam-gel casting-freeze drying method combined with segmented calcination process. The results of SEM, TEM , and XRD analyses of the (5RE 1/5 ) 2 Zr 2 O 7 PCs indicated the formation of a defective fluorite crystal structure, with the rare earth elements homogeneously distributed. Meanwhile, the as-prepared (5RE 1/5 ) 2 Zr 2 O 7 PCs exhibited high porosity, low bulk density, low thermal conductivity , and relatively high compressive strength . Moreover, the high-temperature thermal conductivity of the samples was evaluated, and the results showed that the (5RE 1/5 ) 2 Zr 2 O 7 PCs maintain a thermal conductivity of 0.150 ± 0.002 W m −1 K −1 even at 1000 °C. The strategy used in this paper can be extended to the synthesis of other high-entropy porous ceramics with high porosity and low thermal conductivity, which is suitable for applications as thermal insulation materials.
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Frontiers in Cellular and Infection Microbiology
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2022
·
IF 6.073
Yin Lujun,Shen Wang,Liu Jun-Sheng,Jia Ai-Qun
Siderophore is necessary for the survival of microorganisms and is interregulated with quorum sensing (QS) systems. It is related to growth, proliferation, virulence, and other bacterial social activities as a virulence factor. Thus, we speculated that the QS system could be occluded by inhibiting siderophore production. 2-Hydroxymethyl-1-methyl-5-nitroimidazole (HMMN), one siderophore inhibitor of Pseudomonas aeruginosa PAO1 (P. aeruginosa PAO1), was obtained by using the Chromeazurol S (CAS) method. We found that HMMN inhibited siderophore production and influenced the biological effects of QS regulation, including biofilm formation and pyocyanin production. HMMN (150 μg/ml) inhibited the siderophore production of P. aeruginosa PAO1 by 69.37%. In addition, HMMN could inhibit pyocyanin production and biofilm formation and erase the formed biofilm of P. aeruginosa PAO1. HMMN (150 μg/ml) inhibited the biofilm formation of P. aeruginosa PAO1 by 28.24%. The erasure rate of the formed biofilm reached 17.03%. Furthermore, HMMN (150 μg/ml) inhibited P. aeruginosa PAO1 pyocyanin production by 36.06%. Meanwhile, positive-control hordenine (500.0 μg/ml) reduced the biofilm formation and pyocyanin production of P. aeruginosa PAO1 by 14.42% and 34.35%, respectively. The erasure rate of hordenine to the formed biofilm is 11.05% at 500 μg/ml. Quantitative real-time polymerase chain reaction (qRT-PCR) showed that HMMN downregulates not only siderophore-related genes but also QS-related genes, as well as hordenine. These results suggest that a siderophore inhibitor could be used as a QS inhibitor to occlude the QS system and reduce virulence.
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PubMed
高影响因子
FUEL
·
2022
·
IF 8.035
Zixuan Ma,Fenghai Cao,Yuhao Yang,Liyan Wang,Tao Zhang,Minghui Tan,Guohui Yang,Yisheng Tan
Bifunctional catalysts composed of ZnCrO x oxide and ZSM-5 were widely used in syngas-to-aromatics (STA). The CO conversion on bifunctional catalysts was generally higher than that on oxide catalysts attributed to the pulling effect of zeolite, but the key factor for the improvement of CO conversion was still short of systematical explanation. In this work, the degree of nonstoichiometric spinel of ZnCrO x (ZxC) oxides was finely tuned through modulating the ratio of Zn/Cr, which could significantly influence the catalytic behaviors of ZnCrO x /ZSM-5 catalysts for the CO hydrogenation to aromatics. The increase of nonstoichiometric spinel corresponded to the increase of oxygen vacancies and the enhancement of Zn-Cr synergistic effect, which promoted the activation of H 2 and CO, leading to a dramatic increase of CO conversion. The work revealed that the action of ZnO and oxygen vacancies was the key factor for CO pulling in ZnCrO x oxide and ZSM-5 catalyzed STA reaction.
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JOURNAL OF THE AMERICAN CERAMIC SOCIETY
·
2022
·Vol. 105
·期 11
·6816-6825
·
IF 4.186
De-Bao Liu,Bao-Lu Shi,Yi-Guang Wang,Bao-Sheng Xu
In this work, we have prepared a novel yttria-stabilized zirconia fiber (YSZ f )-reinforced (La 1/5 Nd 1/5 Sm 1/5 Gd 1/5 Yb 1/5 ) 2 Zr 2 O 7 porous ceramics (YSZ f /(5RE 1/5 ) 2 Zr 2 O 7 PCs) through a foam-gelcasting-freeze drying process. The microstructure, phase composition, density, porosity, thermal conductivity, and compressive strength of the as-prepared YSZ f /(5RE 1/5 ) 2 Zr 2 O 7 PCs were systematically investigated. In addition, the high-temperature thermal cycle stability and thermally insulating property of the samples were also tested. The results indicated that the as-synthesized YSZ f /(5RE 1/5 ) 2 Zr 2 O 7 PCs (with 25 wt% YSZ fibers) exhibited high porosity, high compressive strength, low thermal conductivity as well as low thermal cycling shrinkage. This work demonstrated that the added YSZ fiber can remarkably improve the strength of (5RE 1/5 ) 2 Zr 2 O 7 PCs with the high porosity, and as-developed YSZ f /(5RE 1/5 ) 2 Zr 2 O 7 PCs would be an excellent candidate for high-temperature thermal insulator materials.
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Frontiers in Chemistry
·
2022
·
IF 5.545
Zhu Jun,Kong Ling-Qi,Chen Qin-Hua,Li Bin,Wu Lun,Ran Feng-Ying,Ke Li-Na,Zeng Xiao-Hua,Wang Hong-Mei
Marine alkaloids have novel structures and antitumor activities. Therefore, we synthesized rhopaladins’ analogs from marine alkaloids rhopaladins A-D and modified their structures to synthesize 4-benzylidene-5-pyrrolidone derivatives. Among the compounds, (2E, 4E)-4-(4-chlorobenzylidene)-2-(4-chlorostyryl)-N-cyclohexyl-1-(4-fluorophenyl)-5-oxopyrrolidine-2-carboxamide (RPDPRH) has high efficiency and less hepatotoxicity, with IC50 values of 4.66, 6.42, 17.66, 15.2, 12.36, 22.4, and 243.2 μM in vitro anti-proliferative activity testing against cervical cancer C-33A, CaSki, SiHa, and HeLa cells, human hepatocarcinoma HepG2 and 7402 cells, and human normal liver LO2 cells, respectively. In particular, RPDPRH has similar activity to cisplatin on human hepatocarcinoma cells, and cisplatin served as a positive control in our study. Next, the apoptosis of HepG2 and 7402 cells induced by RPDPRH at different concentrations was detected by Annexin V/PI flow cytometry. Moreover, the expression of apoptotic proteins was detected by Western blot analysis. Finally, the results showed that RPDPRH could induce apoptosis of hepatocarcinoma cells by regulating Bax and Bcl-2 expressions. In summary, our results indicate that RPDPRH has the potential to serve as an antitumor agent and plays a significant role in future studies.
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PubMed
高影响因子
Journal of Chemistry
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2022
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IF 3.241
Yan Jin,Xinyuan Wang,Ya-Ping Dong
The Yellow River is very important for human health and social development in China to require good water quality. This study selected the Ningxia section of the Yellow River as the study area to investigate the water quality variation in 2016–2020. A total of 9 water quality parameters were monitored, and 8 parameters including pH, dissolved oxygen, biological oxygen demand, chemical oxygen demand, total phosphate, fluoride, ammonia-nitrogen, and permanganate index were in the range of Class II standard requirement. Dissolved oxygen concentrations ranged from 7.5 to 9.4 mg/L. However, total nitrogen concentrations in 2018–2020 ranged from 1.87 to 2.8 mg/L to cause the pollution. Both the Nemerow index method and the contamination degree method showed that total nitrogen with high concentration exerted the water pollution. Principal component analysis also proved this. Stricter environmental management strategies for controlling total nitrogen should be taken in the future. The findings provided some useful information for water pollution of the Ningxia section of the Yellow River.
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高影响因子
BioEnergy Research
·
2022
·Vol. 16
·期 2
·1108-1120
·
IF 3.852
Xie Ruosong,He Weiwei,Qu Guangfei,Wu HuanHuan,Li Ziying,Li Junyan,Li Weijie
The application of biomass pyrolysis was still limited owing to the high pyrolysis temperature and the complicacy of pyrolysis products. In this work, a homogeneous low-temperature cellulose catalytic pyrolysis system is proposed to directional products 5-methylfurfural. The low-temperature catalytic activity and products distribution of cellulose pyrolysis in [bmim][FeCl 4 ] (Fe-IL) and [bmim] 2 CoCl 4 (Co-IL) at temperature gradients from 150 to 300 °C were studied. As the results, both Fe-IL and Co-IL can catalyze the pyrolysis of cellulose, especially for Fe-IL, which effectively reduced the pyrolysis temperature of cellulose to 200 °C. Nano-scale and micron-scale particles were produced by the catalysis of Fe-IL and Co-IL, respectively. Fe-IL have a high selectivity for the production 5-methylfurfural (5-MF) and furfural (FF), which were 71.12% and 19.14% respectively at the pyrolysis temperature of 200 °C. Furthermore, the mechanism of low-temperature catalytic pyrolysis and the directional evolution mechanism of 5-MF and FF were suggested. Graphical abstract
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高影响因子
CHEMICAL PHYSICS LETTERS
·
2022
·
IF 2.719
Xiaoli Song,Yuxiu Fu,Yaming Pang,Liguo Gao
La and Zn species were used to modify HZSM-5 zeolite, which was used to treat phenol in wastewater. Through the combination of multiple direct tools, La and Zn species were successfully loaded into the HZSM-5 zeolite. La-Zn/HZSM-5 zeolite has a small band gap and the catalyst can produce highly active electrons and electron holes when energy enters. The HZSM-5 zeolite after modification improves activity and stability of the catalyst. Therefore, it has a significant effect in the phenol removal experiment. Adding 1.2 mL of hydrogen peroxide and 0.11 g of catalyst, the removal rate can reach 99.38 % after being irradiation with a mercury lamp at 60 °C for 180 min. La-Zn/HZSM-5 zeolite has great potential in the application of photocatalytic degradation of phenol.
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Molecular Catalysis
·
2022
·
IF 5.089
Wenpeng Han,Shujuan Wang,Yajie Liu,Chaoqun Li,Ningning Yuan,Ligong Zhou,Mingxing Tang,Hui Ge
The transformation of biomass to liquid fuels and chemicals is of great interests. Herein, a series of reduced NiZn-CT (CT represents calcination temperature) catalysts with flower-like morphology and uniform particle sizes were prepared by co-precipitation method and used for hydrogenolysis of 5-hydroxymethylfural (HMF) to 2,5-dimethyfuran (DMF). The characterizations evidenced the formation of NiZn alloy phase in the catalysts through the strong metal-support interaction (SMSI), which had high C-O hydrogenolysis ability. The synergy of hydrogenation and C-O hydrogenolysis is essential for HMF to DMF, and we surprisingly found that this synergistic effect can be achieved just by controlling calcination temperature to regulated SMSI between Ni and ZnO. By this way, 99% DMF yield was gained at 180 °C for 4 h under 2 MPa H 2 over reduced NiZn-450 catalyst. More importantly, the active centers of this Ni/ZnO catalyst exhibited outstanding stability. There was no significant decrease in activity after reusing 9 times. The current research provided an easy-made catalytic system for HMF hydrogenolysis.
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CANADIAN JOURNAL OF CHEMICAL ENGINEERING
·
2022
·Vol. 101
·期 6
·3234-3245
·
IF 2.5
Luxin Zhang,Meng Hu,Ruijun Sun,Xu Xing
The production of 5-ethoxymethylfurfural (EMF) from cheap and abundant glucose feedstock has attracted a great deal of attention because of its potential applications. Herein, three porous tetra-component metal oxide solid acid catalysts (SO 4 2− /ZFSA-A, SO 4 2− /ZFSA-F-10, SO 4 2− /ZFSA-F-20) containing both Brønsted and Lewis acid sites have been successfully synthesized and can efficiently catalyze the synthesis of EMF from glucose. Particularly, the SO 4 2− /ZFSA-A, SO 4 2− /ZFSA-F-10, and SO 4 2− /ZFSA-F-20 catalysts were prepared under the template of sodium alginate, 10% F127, and 20% F127, respectively. The prepared catalysts were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), N 2 -adsorption–desorption isotherm, X-ray photoelectron spectroscopy (XPS), thermogravimetry (TG), temperature-programmed desorption of ammonia (NH 3 -TPD), and pyridine infrared spectra (Py-FTIR). The characterization results indicated that all three catalysts have a porous structure. The pore distribution of the SO 4 2− /ZFSA-A catalyst is mainly macroporous and mesoporous, while the SO 4 2− /ZFSA-F-10 and SO 4 2− /ZFSA-F-20 catalysts are mainly mesoporous. The SO 4 2− /ZFSA-F-20 catalyst exhibited the highest catalytic performance due to its large specific surface area, desirable mesoporous structure, high total acidity (especially strong and super strong acidity), and appropriate Lewis/Brønsted acid ratio. By applying SO 4 2− /ZFSA-F-20, the formation of EMF from glucose was successfully catalyzed and EMF was obtained at a yield of 34.56% after 12 h at 160°C. This yield is much higher compared with most other results achieved by solid acids catalysis. In addition, the reaction parameters such as reaction temperature, reaction time, glucose amount, and catalyst dosage were shown to have a significant effect on the catalytic performance. Notably, the SO 4 2− /ZFSA-F-20 catalyst exhibited good reusability, as its activity did not significantly diminish after four rounds of repeated experiments and was successfully reactivated after calcination.
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