GREEN CHEMISTRY
·
2017
·Vol. 19
·期 21
·5103-5113
·
IF 9.125
Ying Duan,Min Zheng,Dongmi Li,Dongsheng Deng,Lu-Fang Ma,Yanliang Yang
The catalytic conversion of HMF to 2-hydroxy-3-methyl-2-cyclopenten-1-one (MCP), which is a valuable edible essence that has traditionally been obtained from adipic acid, was achieved with an isolated yield of 58%. This procedure comprised two steps: the hydrogenation of 5-hydroxymethylfurfural (HMF) to 1-hydroxy-2,5-hexanedione (HHD) in water on Pd/Nb2O5 catalysts and then the isomerization of HHD to MCP in the presence of a base. The Nb2O5 supports, which were acidic, were characterized by FTIR, XRD and NH3-TPD. The supported Pd/Nb2O5 catalysts, in which Pd was highly dispersed, were synthesized employing cyclohexene as a reductant and were characterized by XRD, TEM, ICP-AES, XPS, EDX and CO pulse chemisorption. The high conversion of HMF was attributed to the high dispersion of Pd, and the acidity of the supports led to high selectivity for HHD. The conversion of HHD to MCP was an intramolecular aldol condensation reaction, and the protonic solvent favored this reaction. Ca–Al was proved to be an effective solid base for the conversion of HHD to MCP in water.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
Cell Reports Physical Science
·
2025
·
IF 7.3
Zhongzhe Wei,Xu Liu,Mingxuan Wang,Yao Lv,Songtao Huang,Jing Wang,Ming Jiang,Zhixiang Yang,Zihao Yao,Sheng Dai,Xiaonian Li,Jianguo Wang
The semi-hydrogenation of alkynes represents a paramount chemical transformation in the synthesis of fine chemicals and pharmaceuticals. However, the structural evolution of active sites during the reaction remains elusive. Here, we constructed a self-adaptive Pd/Nb 2 O 5 catalyst for efficient semi-hydrogenation of alkynes. Mechanistic studies disclose that Pd/Nb 2 O 5 intelligently modulates its structure in response to the specific alkyne type, efficiently preventing Pd poisoning by weakening the strong adsorption of alkynes. During the hydrogenation of aliphatic alkynes, the Pd/Nb 2 O 5 interface undergoes dynamic changes, generating oxygen vacancies (O v ) in situ through hydrogen spillover. In contrast, for the case of reactants of aromatic alkynes, the interface sites remain relatively stable. Coverage-dependent kinetics reveal that the dynamic O v formation of Pd/Nb 2 O 5 is determined by the distinct adsorption mechanism of aromatic and aliphatic alkynes. Due to the evolving interface, Pd/Nb 2 O 5 exhibits a high turnover frequency value of 55,338 h −1 , breaking the linear scaling relationships.
研究领域:
催化
·
化学反应工程
·
材料科学
·
有机合成
✓ 已验证
产品关联
DOI
高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2022
·Vol. 135
·期 3
·1541-1552
·
IF 1.843
Zhang Zhenwei,Ma Xiaoshi,Yue Chuanjun,Wei Xuejiao,Liu Baoliang
Furfuryl ethyl ether (FEE), an important gasoline additive, is synthesized by a one-step reductive etherification of furfural (FF) by Nb 2 O 5 nanowires loaded with Pd as catalysts. Compared with other materials, the catalyst had a suitable synergistic effect between the reductive sites Pd 0 and the acidic sites of Nb 2 O 5 nanowires, effectively improving the yield of FEE. In ethanol, at 453 K and under 1 MPa H 2 pressure, the catalyst 1.0 wt% Pd/Nb 2 O 5 showed excellent catalytic performance in the reductive etherification reaction, and the yield of FEE reached 87.7%, higher than Pd/C whose yield was 81%. This result showed a feasible way to simplify the FEE preparation process, thus reducing production costs.
研究领域:
催化化学
·
绿色化学
·
纳米材料化学
·
能源化工
·
有机合成
✓ 已验证
DOI
高影响因子
FUEL
·
2025
·
IF 7.5
Xuan Liu,Hao Xu,Hao Li
The conventional Hydrogenation deoxygenation (HDO) process is accompanied by harsh reaction conditions (high temperature, high hydrogen pressure, and long reaction time), leading to problems such as easy catalyst deactivation and poor product selectivity. Therefore, the design of hydrodeoxygenation catalysts that can achieve controllable reaction paths, directional product selectivity and high reaction efficiency under mild conditions has become the key to the problem. Phenolic resin (RF) formed by resorcinol–formaldehyde condensation reaction was introduced as a carbothermal reducing agent to prepare oxygen defect-rich Pd/Nb 2 O 5 -T-RF catalysts. The concentration of oxygen defects on the catalyst surface was changed by adjusting the calcination temperature, which affected the electronic properties and acid properties of the catalyst surface interface and promoted the C-O bond breaking. At 25 ℃ and 80 min, Pd/Nb 2 O 5 -700-RF obtained 100 % Vanillin (VAN) conversion and 98.0 % 2-methoxy-4-methylphenol (MMP) selectivity, and the catalytic performance was significantly better than that of the catalysts without RF treatment as well as other calcination temperatures. Characterization and experimental results showed that the electron-deficient oxygen defect facilitated the adsorption and activation of vanillin and vanillyl alcohol, while promoting the hydrogen spillover on the catalyst surface and improving the HDO catalytic performance. In addition, the method is universal for reducible transition metal oxides and can be further extended to different metal oxide catalysts and applied to other fields.
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CATALYSIS
·
2023
·
IF 7.3
Hao Xu,Hao Li
Constructing heterogeneous catalysts with high efficiency and stability to achieve biomass HDO under comparatively mild conditions is an arduous challenge. Crystal phase of metal oxides supports could affect the geometric and electronic properties, causing the variation of catalytic performance. Herein, a series of Pd/Nb 2 O 5 catalysts of pseudohexagonal crystal phase (Nb 2 O 5 -TT), orthorhombic phase (Nb 2 O 5 -T) and monoclinic phase (Nb 2 O 5 -H) are prepared through regulating the annealing temperature. Impressively, Pd/Nb 2 O 5 -T catalyst showed amazing catalytic performance of 100% conversion and 98.9% selectivity of 2-methoxy-4-methylphenol (MMP) at room temperature (25℃) within 30 min, superior than Pd/Nb 2 O 5 -TT, Pd/Nb 2 O 5 -H and other Pd-based catalysts that had been reported. Besides, the Pd/Nb 2 O 5 -T perform robust stability and maintain its high activity after ten times recovery experiment. This catalytic system is also suitable for different kinds of aldehydes compounds at room temperature, exhibiting the high activity and selectivity towards deoxygenated products. Based on the characterizations and experimental validations, it has confirmed that the strong metal-support interaction (SMSI) effect generates via electron transfer between Pd species and Nb 2 O 5 -T support, where in situ reduction of PdO occurred during the reaction, generating active interfacial Pd-O-Nb sites and accelerating the breaking of C-O bonds. The insights of this work provide a guiding direction for the future design of highly selective heterogeneous catalysts by crystal phase modulation engineering.
研究领域:
催化化学
·
材料科学
·
能源化学
✓ 已验证
产品关联
DOI
高影响因子
ChemSusChem
·
2015
·Vol. 8
·期 10
·1761-1767
·
IF 7.657
Yi Shao,Qineng Xia,Xiaohui Liu,Guanzhong Lu,Yanqin Wang
Graphical Mild mannered: Under mild conditions (170 °C, 2.5 MPa), Pd/10 %Nb 2 O 5 /SiO 2 is effective for the hydrodeoxygenation reactions of 4-(2-furyl)-3-buten-2-one (the aldol adduct of furfural with acetone), palmitic acid, tristearin, and diphenyl ether (model compounds of vegetable oils, microalgae oils, and lignin) and gives high yields (>94 %) of alkanes with little C C bond cleavage. A simple Pd-loaded Nb 2 O 5 /SiO 2 catalyst was prepared for the hydrodeoxygenation of biomass-related compounds to alkanes under mild conditions. Niobium oxide dispersed in silica (Nb 2 O 5 /SiO 2 ) as the support was prepared by the sol–gel method and characterized by various techniques, including N 2 adsorption, XRD, NH 3 temperature-programmed desorption (TPD), TEM, and energy-dispersive X-ray spectroscopy (EDAX) atomic mapping. The characterization results showed that the niobium oxide species were amorphous and well dispersed in silica. Compared to commercial Nb 2 O 5 , Nb 2 O 5 /SiO 2 has significantly more active niobium oxide species exposed on the surface. Under mild conditions (170 °C, 2.5 MPa), Pd/10 %Nb 2 O 5 /SiO 2 was effective for the hydrodeoxygenation reactions of 4-(2-furyl)-3-buten-2-one (aldol adduct of furfural with acetone), palmitic acid, tristearin, and diphenyl ether (model compounds of microalgae oils, vegetable oils, and lignin), which gave high yields (>94 %) of alkanes with little C C bond cleavage. More importantly, owing to the significant promotion effect of NbO x species on C O bond cleavage and the mild reaction conditions, the C C cleavage was considerably restrained, and the catalyst showed an excellent activity and stability for the hydrodeoxygenation of palmitic acid with almost no decrease in hexadecane yield (94–95 %) in a 150 h time-on-stream test.
研究领域:
催化化学
·
能源化学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHINESE JOURNAL OF CATALYSIS
·
2019
·
IF 4.914
Yaxuan Jing,Yu Xin,Yong Guo,Xiaohui Liu,Yanqin Wang
Aldol condensation is of significant importance for the production of fuel precursors from biomass-derived chemicals and has received increasing attention. Here we report a Nb 2 O 5 catalyst with excellent activity and stability in the aldol condensation of biomass-derived carbonyl molecules. It is found that in the aldol condensation of furfural with 4-heptanone, Nb 2 O 5 has obviously superior activity, which is not only better than that of other common solid acid catalysts (ZrO 2 and Al 2 O 3 ), more importantly, but also better than that of solid base catalysts (MgO, CaO, and magnesium-aluminum hydrotalcite). The detailed characterizations by N 2 sorption/desorption, NH 3 -TPD, Py-FTIR and DRIFTS study of acetone adsorption reveal that Nb 2 O 5 has a strong ability to activate the C=O bond in carbonyl molecules, which helps to generate a metal enolate intermediate and undergo the nucleophilic addition to form a new C–C bond. Furthermore, the applicability of Nb 2 O 5 to aldol condensation is extended to other biomass-derived carbonyl molecules and high yields of target fuel precursors are obtained. Finally, a multifunctional Pd/Nb 2 O 5 catalyst is prepared and successfully used in the one-pot synthesis of liquid alkanes from biomass-derived carbonyl molecules by combining the aldol condensation with the sequential hydrodeoxygenation .
研究领域:
催化
·
化学工程
·
可再生能源
·
有机化学
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）