RSC Advances
·
2020
·Vol. 10
·期 71
·43599-43606
·
IF 3.119
Xiaomeng Dou,Wenzhi Li,Chaofeng Zhu,Xiao Jiang,Hou-min Chang,Hasan Jameel
Efficient cleavage of aryl–ether linkages is a key strategy for generating aromatic chemicals and fuels from lignin. Currently, a popular method to depolymerize native/technical lignin employs a combination of Lewis acid and hydrogenation metal. However, a clear mechanistic understanding of the process is lacking. Thus, a more thorough understanding of the mechanism of lignin depolymerization in this system is essential. Herein, we propose a detailed mechanistic study conducted with lignin model compounds (LMC) via a synergistic Co–Zn/Off-Al H-beta catalyst that mirrors the hydrogenolysis process of lignin. The results suggest that the main reaction paths for the phenolic dimers exhibiting α-O-4 and β-O-4 ether linkages are the cleavage of aryl–ether linkages. Particularly, the conversion was readily completed using a Co–Zn/Off-Al H-beta catalyst, but 40% of α-O-4 was converted and β-O-4 did not react in the absence of a catalyst under the same conditions. In addition, it was found that the presence of hydroxyl groups on the side chain, commonly found in native lignin, greatly promotes the cleavage of aryl–ether linkages activated by Zn Lewis acid, which was attributed to the adsorption between Zn and the hydroxyl group. Followed by the cobalt catalyzed hydrogenation reaction, the phenolic dimers are degraded into monomers that maintain aromaticity.
研究领域:
化学工程
·
催化
·
有机化学
·
木质素解聚
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMISTRY-A EUROPEAN JOURNAL
·
2014
·Vol. 20
·期 45
·14744-14755
·
IF 5.696
Jiao Chen,Weiming Hua,Yu Xiao,Qisheng Huo,Kake Zhu,Xinggui Zhou
The crystallization of zeolite beta in a dry gel system is found to follow the orientated attachment growth route, escorted with a temporal morphology change from bulky gel, through aggregation of the particulate to large zeolitic crystals. Modification of the precrystallized gel with organosilanes can be used to tune the morphology of the ultimate beta. When hexadecyltrimethoxysilane (HTS) is employed to modify precrystallized gel, a resumed secondary growth produces a hybrid mesocrystal of agglomerated nanozeolites. Combustive removal of organics leads to the formation of hierarchically porous zeolite beta of 100 to 160 nm, composed of nanocrystal building units ranging from 20 to 40 nm, with a noticeable micropore volume of 0.19 mL g −1 and a meso/macropore size between 5 and 80 nm. Conversely, when 1,8-bis(triethoxysilyl)octane (BTO) is utilized to modify the same precrystallized gel, assemblages of discrete beta nanozeolite of around 35 nm are generated. These assemblages construct a hierarchical zeolite beta with a micropore volume of 0.20 mL g −1 and auxiliary pores ranging from 5 to 100 nm. Both organosilanes bring about well-connected hierarchical pore networks. HTS has little effect on the Brønsted/Lewis acidity, whereas BTO causes a substantial reduction of strong Brønsted acid sites. The hierarchical beta zeolite-supported Pt catalyst exhibits improved catalytic performance for the hydroisomerization of n -heptane. Graphical Tailor-made zeolite beta : The orientated attachment growth of zeolite beta in a dry gel system can be developed into a method to fabricate hierarchically porous beta (see figure). The pore connectivity, particle size, and acid properties are tunable with the assistance of organosilane additives. The Pt supported on hierarchical beta outperforms the conventional counterpart in n -heptane hydroisomerization.
研究领域:
材料化学
·
催化化学
·
纳米材料科学
·
多孔材料
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Xiaoling Liu,Yitong Liu,Yue Wu,Shan Dong,Guoqin Qi,Cailing Chen,Shibo Xi,Pan Luo,Yihu Dai,Yu Han,Yu Zhou,Yu Guo,Jun Wang
Catalytic oxidation of volatile organic compounds like formaldehyde (HCHO) over the noble metals catalysts at room temperature is among the most promising strategies to control indoor pollution but remains one challenge to maximize the efficiency of noble metal species. Herein, we demonstrated the straightforward encapsulation of highly dispersive Pt nanoparticles (NPs) within BEA zeolite and adjacent with the surface hydroxyl groups to reach the synergistic HCHO oxidation at 25 °C. High efficiency and long-term stability was reached under large space velocity (∼100% conversion at 180,000 mL (g cat × h) −1 and >95% at 360,000 mL (g cat × h) −1 ), affording rapid elimination rate of 129.4 μmol (g Pt × s) −1 and large turnover frequency of 2.5 × 10 −2 s −1 . This is the first synergy example derived from the hydroxyl groups and confined noble metals within zeolites that accelerated the rate-determining step, the formate transformation, in the HCHO elimination.
研究领域:
环境科学
·
催化
·
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2013
·
IF 2.206
Jiangfeng Yang,Junmin Li,Wei Wang,Libo Li,Jinping Li
Three hydrophobic microporous high-silica zeolites, DDR (with an 8-membered ring), silicalite-1 (a 10-membered ring), and beta (a 12-membered ring) were synthesized. The Si/Al ratios were 230, 1350, and 35, respectively. The samples were characterized by X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, water vapor adsorption, and volumetric nitrogen adsorption. They were tested for their CO2, CH4, and N2 adsorption properties at pressures of up to 10 bar at 288–313 K after activation, and the results were correlated with the Langmuir model. The heat of adsorption was calculated using the Clausius–Clapeyron equation based on the adsorption isotherms. These data were used to estimate the separation selectivities for CO2/CH4 and CH4/N2 binary mixtures at 298 K, using the ideal adsorbed solution theory (IAST) model. Experimental results showed that DDR and beta have good selectivities for CO2/CH4, because they have narrow pores (DDR) or more balance metal ions (relatively low Si/Al ratios beta) effect separately. The synthesized silicalite-1 has the lowest SCO2/CH4 but has the most suitable orifices for methane adsorption and the highest SCH4/N2. In addition, the breakthrough data for CH4/N2 mixtures further indicates that silicalite-1 is more suitable for the CH4 enrichment than the commercially used sorbents zeolite-5A and 13X. From the reproducibility of CH4 and N2 adsorption isotherms on silicalite-1, we can infer that which has the potential to be a commercial sorbent by the stable adsorption properties.
研究领域:
材料科学
·
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF ENERGY RESEARCH
·
2019
·Vol. 43
·期 6
·2075-2085
·
IF 3.343
Rong Dai,Ziliang Zheng,Chenshuai Lian,Xing Li,Xu Wu,Xia An,Xianmei Xie
Summary A novel Pt-based Beta encapsulated CeO 2 yolk-shell catalyst was successfully synthesized via a RF layer in the synthetic process. The CeO 2 @Pt-Beta catalyst showed high catalytic activity and stability toward the LT-ESR with respect to the reference Pt-Beta, CeO 2 -Pt-Beta, which benefited from the special yolk-shell structure and the synergistic effect between the CeO 2 movable core and Pt metal. The confinement effect of the yolk-shell architecture contributed to the high dispersion of Pt nanoparticles as well as to the accumulation of reactant molecules in the enclosed void space, which ensured the reactants reacted with CeO 2 and Pt to achieve a complete reaction.
研究领域:
化学工程
·
材料科学
·
能源科学
✓ 已验证
产品关联
DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2025
·
IF 4.7
Bing Yan,Xu Chen,Jie Huang,Guangming Min,Zonghui Liu,Lei Shi,Bing Xue
The process of producing para -xylene (PX) from 2,5-dimethylfuran (DMF) via Diels-Alder (D-A) cycloaddition over Beta zeolites was recognized as a green and sustainable pathway for PX production. Theoretically, small zeolite particles need to be synthesized to mitigate mass transfer limitations caused by their inherent microporous structure, but particle size changes simultaneously alter crystallinity, acidity, and pore characteristics. The effects of these factors on the Diels-Alder (D-A) cycloaddition reaction have not yet been fully elucidated. In this study, Beta zeolites with average particle sizes of 100 nm, 180 nm, 450 nm, and 760 nm were prepared and applied to the D-A cycloaddition of DMF reaction. All Beta zeolites exhibited a polycrystalline structure composed of nanocrystallites and featured both micropores and mesopores. The turnover frequency (TOF) of Beta zeolite with 760 nm particle size was approximately one-third that of the other three zeolites at 160 °C, and its apparent activation energy ( E a ) for PX formation was significantly lower than that of the smaller-particle zeolites. The reduced activity and E a were primarily attributed to significant mass transfer limitation in larger-particle zeolites, with this limitation mainly originating from lengthened diffusion paths, diminished mesoporosity, mismatch in structure, and micropore alignment by internal grain boundaries. Within the particle size range where mass transfer limitations were eliminated, excessively small particle size can also detrimentally impact catalytic performance, owing to easier crystallinity reduction during the reaction.
研究领域:
催化化学
·
化学反应工程
·
材料科学
·
绿色化学
·
石油化工
✓ 已验证
产品关联
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
·
2020
·
IF 3.99
En-Hui Yuan
A series of Beta zeolites has been carefully prepared by the conventional hydrothermal method under various ratios of H 2 O/SiO 2 ranging from 10 to 60. These zeolite materials are thoroughly characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen adsorption-desorption, temperature programmed desorption of ammonia (NH 3 -TPD) and etc. It reflects that the water concentration (H 2 O/SiO 2 ratios) has great impact on the zeolites nucleation and growth rates, resulting in the different crystals morphologies, size distributions and textural properties for the obtained Beta zeolite materials. These primary results are very help for guiding rational design of the zeolite catalysts with different topologies and other related materials for specific applications.
研究领域:
材料科学
·
催化
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
Results in Engineering
·
2023
·
IF 5
Yeqing Huang,Manna Wang,Yi Huang,Jin Shang,Baoyu Liu
The distribution of Brønsted acid sites in three-dimensional 12-membered pore channels of Beta zeolite was a decisive factor in the alkylation of benzene with cyclohexene. Here, the Brønsted acid site distribution in Beta zeolitic channels was precisely regulated by tuning the content of Na + in crystallization system combined with tetraethylammonium cation, the Beta-55 with Brønsted acid sites exclusively located in straight channels (along a - and b -axis directions) was successfully synthesized by utilizing tetraethylammonium as the structure-directing agents without Na + species, and the fraction of Brønsted acid sites in sinusoidal/straight channels of Beta zeolites can be accurately controlled by tailoring the content of Na + in synthesis gel. Catalytic properties in the liquid alkylation between benzene and cyclohexene exhibited that Beta-55 zeolites with the Brønsted acid sites solely located in a -axis and b -axis channels showed the highest cyclohexene conversion, cyclohexylbenzene selectivity and longest lifetime in this reaction. In addition, the resultant Beta zeolites also exhibited low coke generation rate and robust regeneration performance in the alkylation reaction.
研究领域:
催化
·
化学工程
·
材料科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2019
·
IF 4.63
Zhiguo Zhu,Haikuo Ma,Mingtong Li,Ting Su,Hongying Lü
Sn-containing Beta (Sn-Beta) zeolite is extensively applied in industrially-relevant reactions as a highly active and robust Lewis acid heterogeneous catalyst. Nonetheless, environmentally-unfriendly fluoride is generally required to the directly hydrothermal synthesis of Sn-Beta. In this work, an innovative strategy of interzeolite transformation with steam-assisted conversion is provided to directly synthesize Sn-Beta zeolite in the absence of fluoride. Silica source of FAU and steam-assisted conversion were two necessary factors for the successful synthesis of Sn-Beta zeolite. It was found that highly crystallized Sn-Beta zeolite with isolated framework Sn ions was hydrothermally synthesized via degradation of siliceous FAU zeolite and recrystallization of degraded silicate species. As far as we know, the crystal of Sn-Beta in this work was minimum in size among all present directly hydrothermal synthesized ones. More importantly, the Sn contents in Sn-Beta could achieve to 2.39 wt % (Si/Sn = 81), breaking through the Sn content restriction of conventional fluoride-mediated method. In addition, the hydrophobicity of this resultant Sn-Beta zeolite was slightly inferior to Sn-Beta-F obtained via traditional fluoride-assisted route. Whereas the smaller crystal size of this Sn-Beta gave rise to relatively good diffusion performance for organics, which made it reveal high activities in the Baeyer-Villiger oxidant of ketones in particular employing bulky tert -butyl hydroperoxide as the oxidant. The current strategy provides an alternative and environmentally-friendly method for the hydrothermal synthesis of Sn-Beta without the assistance of fluoride and alkali metal ions, which can guide further development in metallosilicates crystal engineering in terms of greenization.
研究领域:
材料科学
·
催化
·
环境化学
·
无机化学
✓ 已验证
产品关联
DOI
高影响因子
BMC MUSCULOSKELETAL DISORDERS
·
2024
·Vol. 25
·期 1
·1-11
·
IF 2.2
Du Xiao,Zang Chuanyi,Wang Qinglei
Background Osteoporosis is a genetic disease caused by the imbalance between osteoblast-led bone formation and osteoclast-induced bone resorption. However, further gene-related pathogenesis remains to be elucidated.Methods The aberrant expressed genes in osteoporosis was identified by analyzing the microarray profile GSE100609. Serum samples of patients with osteoporosis and normal group were collected, and the mRNA expression of candidate genes was detected by quantitative real-time polymerase chain reaction (qRT-PCR). The mouse cranial osteoblast MC3T3-E1 cells were treated with dexamethasone (DEX) to mimic osteoporosis in vitro. Alizarin Red staining and alkaline phosphatase (ALP) staining methods were combined to measure matrix mineralization deposition of MC3T3-E1 cells. Meanwhile, the expression of osteogenesis related genes including alkaline phosphatase (ALP), osteocalcin (OCN), osteopontin (OPN), Osterix, and bone morphogenetic protein 2 (BMP2) were evaluated by qRT-PCR and western blotting methods. Then the effects of candidate genes on regulating impede bone loss caused by ovariectomy (OVX) in mice were studied.Results Cyclin A1 (CCNA1) was found to be significantly upregulated in serum of osteoporosis patients and the osteoporosis model cells, which was in line with the bioinformatic analysis. The osteogenic differentiation ability of MC3T3-E1 cells was inhibited by DEX treatment, which was manifested by decreased Alizarin Red staining intensity, ALP staining intensity, and expression levels of ALP, OCN, OPN, Osterix, and BMP2. The effects of CCNA1 inhibition on regulating osteogenesis were opposite to that of DEX. Then, Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis demonstrated that genes negatively associated with CCNA1 were enriched in the TGF-beta signaling pathway. Inhibitor of TGF-beta signaling pathway partly reversed osteogenesis induced by suppressed CCNA1. Furthermore, suppressed CCNA1 relieved bone mass of OVX mice in vivo.Conclusion Downregulation of CCNA1 could activate TGF-beta signaling pathway and promote bone formation, thus playing a role in treatment of osteoporosis.
研究领域:
骨生物学
·
分子生物学
·
遗传学
·
细胞生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
PHYTOMEDICINE
·
2025
·
IF 8.3
Jiao Liu,Danye Niu,Yu Tang,Ruoheng Zheng,Yinyin Qin,Xiuqin Cheng,Shubo Pan,Jinfei Yuan,Xiaohua Shi,Jiao Yang
Background β-Hydroxy β-Methylbutyrate (HMB), derived from leucine, is known for its role in anti-oxidation and anti-inflammation. But, the application of HMB in IBD treatment is not fully understood, highlighting the requirement for further research. Purpose We aimed to examine the effects of HMB treatment on DSS-induced chronic colitis in mice and explore its underlying mechanisms. Methods To simulate colonic inflammation, a murine colitis model was generated by using DSS induction. Critical indicators such as body weight, colon length, disease activity index (DAI), and gross pathology were thoroughly monitored. Immunohistochemistry assay was conducted to assess the expression of Occludin and F4/80. Flow cytometry was employed to evaluate the expression levels of CD80 and CD86. qPCR was performed to measure cytokine expression (IL-6, IL-1β, TNF-α, IL-22, CXCL2, iNOS). RNA sequencing was carried out using bone-marrow derived dendritic macrophage cells (BMDMs). Results Our study indicates that HMB treatment substantially mitigated colonic damage in murine models of DSS-induced colitis, highlighting its anti-inflammatory potential. Notably, HMB significantly enhanced the expression of Occludin in these mice. Furthermore, HMB downregulated proinflammatory markers such as IL-6, IL-1β, and TNF-α as well as CXCL2 in the colon tissue. In vitro experiments also revealed that HMB reduced production of proinflammatory cytokines induced by DSS and suppressed the expression levels of CD80 and CD86 in macrophage cells. On a mechanistic level, we demonstrated the anti-inflammatory effects of HMB by reducing the phosphorylation of p-ERK and p-p65, thereby limiting cytokine production in both in vivo and in vitro settings. Conclusion These findings indicate that HMB possesses anti-inflammation against intestinal inflammation and may hold promise as a potential therapeutic candidate for IBD treatment. There's growing interest in combining traditional anti-inflammatory agents with supplements like HMB to improve outcomes in complex IBD cases. HMB's role in established muscle preservation and reduction of systemic inflammation as described in this study could make it a valuable adjunct in IBD therapy.
研究领域:
免疫学
·
药理学
·
消化病学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MOLECULES
·
2022
·Vol. 27
·期 16
·5077
·
IF 4.927
Hui Liu,Jinhua Luo,Ping Yang,Xiulan Yang,Jun Yan,Qian Yao
Compared to beta-cyclodextrins (beta-CD), hydroxypropyl-beta-cyclodextrins (HP-beta-CD) are a more popular material used to prepare inclusion complexes due to their superior solubility and intestinal absorption. In this study, oleuropein (OL) inclusion complexes with beta-CD (beta-CD:OL) and HP-beta-CD (HP-beta-CD:OL) were prepared and the formation of inclusion complexes was validated by IR, PXRD, and DSC. A phase solubility test showed that the lgK(25 °C) and binding energy of beta-CD:OL and HP-beta-CD:OL was 2.32 versus 1.98, and −6.1 versus −24.66 KJ/mol, respectively. Beta-CD:OL exhibited a more powerful effect than HP-beta-CD:OL in protecting OL from degradation upon exposure to light, high temperature and high humidity. Molecular docking, peak intensity of carbonyls in IR, and ferric reducing power revealed that beta-CD:OL formed more hydrogen bonds with the unstable groups of OL. Both inclusion complexes significantly enhanced the solubility, intestinal permeation and antioxidant activity of OL (p< 0.05). Though HP-beta-CD:OL had higher solubility and intestinal absorption over beta-CD:OL, the difference was not significant (p> 0.05). The study implies that lower binding energy is not always associated with the higher stability of a complex. Beta-CD can protect a multiple-hydroxyl compound more efficiently than HP-beta-CD with the intestinal permeation comparable to HP-beta-CD complex.Keywords:oleuropein;beta-CD;hydroxypropyl-beta-CD;stability;intestinal permeation
研究领域:
药剂学
·
食品科学
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）