查找使用阿拉丁产品的科研文献

A novel strategy for highly efficient conversion of cellulose into 5-hydroxymethylfurfural using green and effective stepwise catalytic systems

Wang Tao,Zhang Cailiang,Feng Hui,Zou Qingjun,Huang Wenrui,Wu Jiacong,Han Juan,Wang Yun

In this study, a green and effective stepwise catalytic system for cellulose conversion to 5-hydroxymethylfurfural (HMF) is reported. In a pretreatment process, very fast (15 min) dissolution of cellulose was achieved at a low temperature of 70 °C, utilizing ZnBr 2 ·4H 2 O as the best dissolution solvent, which to improve the reactivity of cellulase for raw cellulose and increase efficiency of cellulose degradation. Enzyme-inorganic hybrid nanoflowers (Cellulase@β-glucosidase/Zn 3 (PO 4 ) 2 -NF and Glucose isomerase@Zn 3 (PO 4 ) 2 -NF) with different morphological structures were prepared to act as biocatalyst in the sequential conversion of pretreated cellulose to glucose and glucose to fructose. HCl was applied catalyst for dehydration of fructose to 5-HMF in a water/tert-butanol biphasic system. Under optimal reaction conditions, the yield of 5-HMF for the overall reaction from cellulose was about 21.6%. A feasibility route for green conversion of cellulose to 5-HMF is reported. Graphical abstract

H2O2-assisted fabricate nickel cobalt sulfide as the efficient catalyst for the novel strategy of 5-hydroxymethylfurfural stepwise electrolysis

Xifeng Zhang,Yuting Li,Juan Wang,Gaofeng Zeng,Qin Zhong

Electrooxidation of 5‑Hydroxymethylfurfural (HMF) is considered a promising strategy for replacing the sluggish oxygen evolution reaction (OER) of electrolytic water, which can reduce the consumption of hydrogen production and the risk of gas mixing and obtain value-added products. Herein, a nanosheet with nanoflower catalyst (H-0.3Co-Ni 3 S 2 ) was synthesized via a one-step hydrothermal process with the assistance of hydrogen peroxide (H 2 O 2 ) for the electrooxidation of HMF. Adding H 2 O 2 and Co can decrease Ni's outer layer electronic cloud density, which benefits the catalyst's oxidation and catalyzes the HMF electrooxidation. H-0.3Co-Ni 3 S 2 shows the superior performance of the HMF electrochemical oxidation with the initial potential of 1.25 V vs. RHE and the voltage of 1.38 V vs. RHE at 200 mA cm −2 under the electrolyte of 1 M KOH with 10 mM HMF. The conversion rate, yield and Faraday efficiency of HMF electrooxidation for H-0.3Co-Ni 3 S 2 in the electrolyte of 1 M KOH with 10 mM HMF are 98.2 %, 97.6 % and 97.6 %, respectively. Besides, we provide a novel stepwise electrolysis strategy that can inhibit OER effectively while electrolyzing large-concentration HMF rapidly. Finally, in an electrolyte of 1 M KOH with 30 mM HMF, the conversion rate, yield and Faraday efficiency achieve 100 %, 91.9 % and 97.4 %, respectively.

Highly dispersed Co anchored on Ce-doped hydroxyapatite as a dual-functional catalyst for selective hydrogenolysis of 5-hydroxymethylfurfural

Zhuoyou Gao,Mengying Wang,Ningzhao Shang,Wei Gao,Xiang Cheng,Shutao Gao,Yongjun Gao,Chun Wang

Hydrodeoxygenation (HDO) is an indispensable approach to produce renewable biofuels and value-added chemicals using natural biomass and its derivatives. 2,5-Dimethylfuran (DMF) is considered to be a very promising liquid biofuel, and it can be fabricated by HDO of the biomass derivative 5-hydroxymethylfurfural (HMF). Herein, a highly efficient bifunctional catalyst, Co/HAP(Ce), was fabricated by anchoring highly dispersed Co on Ce-doped hydroxyapatite (HAP(Ce)). Co/HAP(Ce) displayed excellent HDO catalytic activity to convert HMF to DMF, and 99% HMF conversion and 96% DMF selectivity can be obtained under 150 °C, 2 MPa H2 conditions for 5 h. Density functional theory calculations revealed that H2 can be more easily activated by Co/HAP(Ce). Systematic studies confirmed that the high activity of Co/HAP(Ce) can be ascribed to the desired acid–alkali properties, highly dispersed cobalt species and strong metal–support interactions. This research provides a cost effective approach for designing efficient catalysts for HDO of biomass and its derivatives.

Efficient conversion of cellulose into 5-hydroxymethylfurfural by inexpensive SO42-/HfO2 catalyst in a green water-tetrahydrofuran monophasic system

Xian Shi,Xinyi Xing,Mengya Ruan,Qichun Wei,Ying Guan,Hui Gao,Siquan Xu

Efficient and green catalysis of cellulose to 5-hydroxymethylfurfural (HMF) is currently a challenge that needs a breakthrough. In this study, a series of inexpensive (x)SO 4 2- /HfO 2 heterogeneous catalysts were prepared and exhibited superior catalytic performance for conversion of cellulose into HMF in the green water-tetrahydrofuran monophasic system (H 2 O-THF). An optimal HMF yield of 54% was acquired through detailed evaluation of reaction conditions. Various analyzes including ICP-OES, XRD, SEM, TEM, FTIR, N 2 adsorption–desorption isotherm, XPS, TG, NH 3 -TPD and Py-FTIR were applied to inspected the physicochemical characteristics of the (x)SO 4 2- /HfO 2 catalysts. Meanwhile, the recyclability of the catalyst and the by-products generated during the reaction process were studied and captured, respectively. The results presented herein show that the catalytic system of (30%)SO 4 2- /HfO 2 catalyst combined with H 2 O-THF monophasic solvent is advanced, and it can be both green and efficient without the presence of other additives and promoters, and has great potential in the future.

Photocatalytic selective oxidation of biomass-derived 5-hydroxymethylfurfural to 2,5-diformylfuran under ambient conditions over CdIn2S4/g-C3N4 heterojunctions

Jifang Cui,Zhihao Yu,Linhao Sun,Ming Zhang,Mengyan Guo,Jian Xiong,Yina Qiao,Rui Zhang,Xuebin Lu

Selective photocatalytic oxidation rather than mineralisation is essential for the catalytic valorisation of biomass, which requires precise control of the generation of reactive oxygen species via the rational construction of heterogeneous junctions. In this paper, CdIn2S4/g-C3N4 (CIS/CNNS) heterojunctions were constructed by a microwave-assisted method and used for selective photocatalytic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF), a key intermediate for fine chemical synthesis and an important furan-based polymer monomer. According to the electron transfer mechanism of the heterojunctions, the effective separation of charges and holes led to a significant enhancement of the utilization efficiency of photogenerated electrons (PGEs). Specifically, the valence band (VB) potential of the constructed heterojunctions did not reach the oxidation potential of ˙OH/OH−, which avoided the massive generation of strongly oxidizing active species ˙OH and thus increased the reaction selectivity. Under visible light irradiation, 65.2% HMF conversion and 91.5% DFF selectivity could be achieved over CIS/CNNS, with a product yield 3.26 times higher than monomeric CdlIn2S4 and 4.2 times higher than monomeric CNNS. The radical quenching experiments verified that ˙O2− was the predominant active species in the reaction process, and the ˙O2− signal of the composite was significantly enhanced in the ESR characterization, achieving highly selective conversion of HMF to DFF.

Insights into the molecular mechanism of a new efficient whole-cell biocatalyst Enterobacter ludwigii YYP3 in 5-hydroxymethylfurfural reduction

Xin Pan,Xue Wang,Sihua Wu,Lei Xu,Leilei Zhang,Zhan Zhang,Bingfeng Li,Xuejun He,Siyuan Chang

Upgrading of the bio-based platform chemical 5-hydroxymethylfurfural (HMF) into high-value derivatives is an important research topic, particularly in green and sustainable chemistry. Herein, we applied a new, highly HMF-tolerant strain, Enterobacter ludwigii YYP3, as a whole-cell biocatalyst for efficient reduction of HMF to 2,5-bis(hydroxymethyl)furan (BHMF). Upon process optimization, within only 3 h, BHMF was produced with a yield >99% and 98.5% selectivity using 100 mM HMF, resulting in the highest space time yield (4.2 g L−1 h−1) among the currently reported HMF bioreduction processes. In a fed-batch conversion, E. ludwigii YYP3 achieved large-scale production of 290 mM BHMF within 9 h and retained its high catalytic activity for three runs (27 h), suggesting an excellent cycling stability. Based on genome and transcriptome analysis, the molecular mechanism underlying the high HMF tolerance of E. ludwigii YYP3 was explored, primarily through the downregulation of genes related to amino acid biosynthetic and metabolic processes and upregulation of genes associated with DNA replication, recombination, and repair; biofilm formation; and redox homeostasis. Meanwhile, two novel short-chain dehydrogenase/reductase family oxidoreductases ElSDR-ykvO and ElSDR-SSP1627 were identified as target enzymes responsible for conversion of HMF to less toxic BHMF in E. ludwigii YYP3. Combined with structure and mutation analysis, the catalytic mechanisms of target enzymes were determined to be based on the active sites Ser, Tyr, and Lys. Our work not only confirms that E. ludwigii YYP3 has promising application prospects in large-scale production of BHMF, but also provides novel insights into understanding the molecular mechanism of HMF reduction.

Synthesis of liver-targeting dual-ligand modified GCGA/5-FU nanoparticles and their characteristics in vitro and in vivo

Mingrong Cheng,Xiaoyan Gao,Yong Wang,Houxiang Chen,Bing He,Yingchun Li,Jiang Han,Zhiping Zhang

One-pot synthesis of 5-Hydroxymethylfurfural from glucose and corn stover in an aqueous choline chloride/ acetone ternary solvent

Qing Qing,Wenxuan Wu,Xiaoran Tao,Zhuang Ma,Weigang He,Yuheng Tao,Liqun Wang

Aqueous choline chloride/acetone was developed as a green ternary solvent for catalytic conversion of glucose and raw corn stover into 5-HMF. The results illustrated that acidic ChCl solution played a vital role in promoting the tandem isomerization/dehydration reaction of glucose to 5-HMF, while acetone was identified as an efficient extracting solvent to simultaneously remove 5-HMF from the aqueous phase. The composition of the ternary solvent system was found to have a significant impact on the 5-HMF yield, reaction selectivity, and preventing the further degradation of 5-HMF. A competitive 5-HMF yield of 73.3 mol% was achieved from glucose catalyzed by an ultra-low H 2 SO 4 loading of 2 mmol at 190 °C for 10 min in the ternary ChCl-H 2 O-acetone solvent with a mass ratio of 1:2:3. This novel solvent system exhibited good stability, high efficiency, and excellent recyclability, employing in catalytic conversion of both glucose and lignocellulose to produce 5-HMF.

Real-time monitoring of 5-HT release from cells based on MXene hybrid single-walled carbon nanotubes modified electrode

Jiang Mengyuan,Tian Liang,Su Mengjie,Cao Xiaoqing,Jiang Qiyu,Huo Xiaolei,Yu Chunmei

Serotonin (5-HT) is an essential inhibitory neurotransmitter in vivo that is critical for interneuronal communication of the nervous system. Herein, we constructed an electrochemical cell-sensing platform for 5-HT detection based on MXene/single-walled carbon nanotubes (SWCNTs) nanocomposite. The one-dimensional SWCNTs with good electrical conductivity are uniformly dispersed on the surface and intermediate layers of the two-dimensional MXene to form a tightly heterogeneous heterostructure. The synthesized MXene-SWCNTs could improve the stacking problem of MXene nanosheets and expose more active sites, effectively promoting the conductive properties and electrochemical activity of the composite. The fabricated MXene-SWCNTs/GCE possessed outstanding detection capability for 5-HT with a wide linear range of 4 nM–103.2 μM and a low detection limit of 1.5 nM. Moreover, the sensor was further applied for the real-time monitoring trace amount of 5-HT releasing from different cell lines, which confirmed its promising applications in 5-HT related physiological and pathological fields. Graphical abstract MXene-SWCNTs/GCE was developed and applied for the real-time monitoring of trace amounts of 5-HT secreted from living cells.

CCCTC-Binding Factor Mediates the Transcription of Insulin-Like Growth Factor Binding Protein 5 Through EZH2 in Ulcerative Colitis

Gu Dan,Cao Ting,Yi Shijie,Liu Ya,Fan Chao

Background Ulcerative colitis (UC) features chronic, non-infectious inflammation of the colon. Insulin-like growth factor binding protein 5 (IGFBP5) has been indicated to be related to various inflammation-related diseases. However, its association with UC remains largely unclear. Aims Here, we investigate the role of IGFBP5 in colonic mucosal epithelial cell injury in UC. Methods Differentially expressed genes in the colonic tissues of UC mice were screened using the Gene Expression Omnibus database, and IGFBP5 was identified. UC mice were developed using dextran sulfate sodium, and IGFBP5 expression in the colonic tissues of UC mice was confirmed by immunohistochemistry and RT-qPCR. The effects of IGFBP 5 in vivo and in vitro were investigated by intraperitoneal injection of adeno-associated virus into UC mice or by transfection with an IGFBP5 overexpression plasmid into lipopolysaccharide-treated colonic mucosal epithelial cells. The mechanisms causing IGFBP5 deletion in UC were predicted by bioinformatics analysis and ChIP-qPCR and verified by rescue experiments. Results IGFBP5 was reduced in UC. IGFBP5 impaired the NFκB pathway in the colonic tissue of UC mice and ameliorated inflammatory infiltration and colonic mucosal cell injury. IGFBP5 depletion was associated with H3K27me3 modification, which was induced by EZH2. CTCF was responsible for recruiting EZH2 to the promoter region of IGFBP5. CTCF inhibition repressed UC progression by reducing H3K27me3 modification via the discouragement of the enrichment of EZH2 in the IGFBP5 promoter. Conclusions CTCF modulates H3K27me3 modification of the IGFBP5 promoter by recruiting EZH2, thereby downregulating IGFBP5 to accentuate colonic mucosal epithelial cell injury in UC mice.

Creation of silanol nests on HZSM-5 catalyst to boost the alkylation of toluene with methanol for PX synthesis

Guoqiang Hou,Tingjun Fu,Xin Li,Qian Ma,Zhong Li

HZSM-5 catalysts with abundant silanol nests were fabricated by removing framework Al, which effectively promoted the selective alkylation of toluene with methanol by inhibiting the deep alkylation of aromatics to heavy aromatics and the conversion of methanol to light hydrocarbons. Correspondingly, the alkylation efficiency reached 65.3% at a toluene conversion of 31.3% over dealuminated HZSM-5, higher than the 55.2% efficiency and 28.0% conversion of parent zeolites, respectively. In situ DRIFTS and single-factor experimental clarified that toluene adsorption was enhanced and methanol to hydrocarbons was inhibited with the presence of silanol nests. Additionally, by increasing the crystal size of HZSM-5 with silanol nests from 2 to 5 µm, para-xylene selectivity was increased from 36.1% to 65.5% because of the enhanced diffusion barrier . The finding of the positive effect of the silanol nests on toluene alkylation can provide a solid fundamental basis for the rational design of catalysts.

5-Aminosalicylic acid ameliorates dextran sulfate sodium-induced colitis in mice by modulating gut microbiota and bile acid metabolism

Huang Ling,Zheng Junping,Sun Guangjun,Yang Huabing,Sun Xiongjie,Yao Xiaowei,Lin Aizhen,Liu Hongtao

Colitis develops via the convergence of environmental, microbial, immunological, and genetic factors. The medicine 5-aminosalicylic acid (5-ASA) is widely used in clinical practice for colitis (especially ulcerative colitis) treatment. However, the significance of gut microbiota in the protective effect of 5-ASA on colitis has not been explored. Using a dextran sulfate sodium (DSS)-induced colitis mouse model, we found that 5-ASA ameliorated colitis symptoms in DSS-treated mice, accompanied by increased body weight gain and colon length, and a decrease in disease activity index (DAI) score and spleen index. Also, 5-ASA alleviated DSS-induced damage to colonic tissues, as indicated by suppressed inflammation and decreased tight junction, mucin, and water–sodium transport protein levels. Moreover, the 16S rDNA gene sequencing results illustrated that 5-ASA reshaped the disordered gut microbiota community structure in DSS-treated mice by promoting the abundance of Bifidobacterium , Lachnoclostridium , and Anaerotruncus , and reducing the content of Alloprevotella and Desulfovibrio . Furthermore, 5-ASA improved the abnormal metabolism of bile acids (BAs) by regulating the Farnesoid X receptor (FXR) and Takeda G-protein-coupled receptor 5 (TGR5) signaling pathways in DSS-treated mice. In contrast, 5-ASA did not prevent the occurrence of colitis in mice with gut microbiota depletion, confirming the essential role of gut microbiota in colitis treatment by 5-ASA. In conclusion, 5-ASA can ameliorate DSS-induced colitis in mice by modulating gut microbiota and bile acid metabolism. These findings documented the new therapeutic mechanisms of 5-ASA in clinical colitis treatment.