ACS Sustainable Chemistry & Engineering
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2016
·
IF 5.267
Qiangqiang Zhu,Bin Wang,Tianwei Tan
For the effect of structural features on the catalytic performance of the conversion of ethanol and acetaldehyde to butadiene to be investigated, a series of MgO–SiO2 catalysts with different structural properties were synthesized by tuning the calcination temperature, investigated, and characterized. The best butadiene selectivity of 80.7% appears for the MgO–SiO2 catalyst calcined at 500 °C using a mixture of acetaldehyde/ethanol/water (22.5:67.5:10 wt %) as feed. Addition of the appropriate amount of water (10 wt %) improved butadiene selectivity by inhibiting the formation of 1-butanol and C6 compounds. Results from XRD, FT-IR, and 29Si MAS NMR indicate the generation of a significant amount of amorphous magnesium silicates along with few crystalline magnesium silicates for the catalyst calcined at 500 °C. XPS results indicate that it contains the lowest binding energies of both Si–O and Mg–O from Si–O–Mg bonds. For the catalysts calcined at low temperature (350 and 400 °C), more 1-butanol and C6 compounds formed, which are considered to be related to residual Mg(NO3)2. Additionally, more ethylene, diethyl ether, and butylene isomers were produced over the MgO–SiO2 catalyst calcined at 700 °C with the formation of forsterite Mg2SiO4. Further results from Fourier transform infrared spectroscopy after pyridine adsorption and CO2 temperature-programmed desorption show that the high catalytic performance is related to the presence of Lewis acidic sites and an intermediate number of basic sites.
研究领域:
催化化学
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材料科学
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DOI
高影响因子
CATALYSIS LETTERS
·
2019
·Vol. 150
·期 5
·1462-1470
·
IF 2.372
Zhang Minhua,Qin Yu’nan,Tan Xuechao,Wang Lingtao,Yu Yingzhe,Jiang Haoxi
Abstract In this paper, the MgO–SiO 2 catalyst was prepared with the deposition–precipitation method, which was used to catalyse the conversion of ethanol to 1,3-butadiene through a two-step process. The carbon deposition deactivation of the catalyst was mainly caused by that the carbon species occupied the acid-basic active sites on the catalyst surface. The carbon deposition mainly includes chain alkanes and aromatic compounds from outer to inner layers, and its site was mainly MgSiO 3 , followed by MgO, while SiO 2 showed weak carbon deposition ability. Graphic Abstract
研究领域:
催化化学
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材料科学
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DOI
高影响因子
Catalysis Science & Technology
·
2016
·Vol. 7
·期 1
·168-180
·
IF 5.287
Xiaoxiong Huang,Yong Men,Jinguo Wang,Wei An,Yuanqiang Wang
A series of magnesia–silica binary composite catalysts with different molar ratios were prepared using various preparation methods and evaluated for the one-step production of 1,3-butadiene (BD) from bio-ethanol. The MgO–SiO2 catalyst prepared by wet-kneading is distinguished from the samples prepared by other methods by its superior activity. An exceptionally high productivity of butadiene with the high ethanol conversion of 95% and BD selectivity of 77% was obtained over wet-kneaded hierarchical flower-like MgO nanostructures with the catalytic material made up of SiO2 spheres (with a MgO : SiO2 molar ratio of 65 : 35 at 450 °C and an WHSV of 4.1 h−1), which translates into an unprecedented BD yield of 0.025 mol gcat−1 h−1. The as-prepared catalysts were characterized by XRD, FESEM, BET, FT-IR, UV/vis, CO2-TPD and NH3-TPD. The Mg precursor used and the preparation method are found to influence the extent of MgO and SiO2 interactions during preparation, as estimated by various techniques, which, in turn, was found to correlate with the catalytic performance. A subtle balance of surface acidity/basicity was found to be necessary to achieve a high butadiene yield which can be obtained by variation of MgO : SiO2 ratios in wet-kneaded samples. In view of the difference in catalytic activity and the physicochemical properties of the MgO–SiO2 composite catalysts, the Si–O–Mg chemical bond formed by the strong MgO and SiO2 interaction is suggested to be essential for the balanced surface acid/base sites in relation to the strong interaction between MgO and SiO2 and the consequent high catalytic performance.
研究领域:
催化化学
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材料科学
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能源化学
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产品关联
DOI
高影响因子
ACS Sustainable Chemistry & Engineering
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2017
·
IF 5.951
Qiangqiang Zhu,Chun Shen,Jie Wang,Tianwei Tan
The upgrade of acetone–butanol–ethanol (ABE) mixture from biomass to high-value biofuels has aroused increasing attention. However, a reported heterogeneous catalyst, metal-containing MgAl-hydrotalcite (HT), is confronted with a serious water-resistance problem due to an inherent memory effect of HT materials. With the aim of exploring catalysts with improved water-resistance, metal-containing MgO–SiO2 catalysts were synthesized and evaluated. An investigation on the effect of metal type including Ni, Cu, Fe, Zn, and Co, metal loading, and reaction temperature on catalytic performance indicates that the 10 wt % Ni–MgO–SiO2 catalyst provides the best catalytic performance, giving a yield of 81.5% to C5–C15 ketones and alcohols at 240 °C. As expected, the catalyst exhibits an excellent water-resistance. It could tolerate up to 3 wt % water, which was much higher than 0.5 wt % over that of Cu- or Pd-HT as reported. Results from XRD and 29Si MAS NMR analyses indicate that the high water-resistance could be ascribed to the more stable structure of magnesium silicates formed in the catalyst than HT materials. For a further study of the effect of catalyst property on catalytic performance, 10 wt % Ni–SiO2, 10 wt % Ni–MgO, and 10 wt % Ni–MgO–SiO2 catalysts were investigated and characterized. Results from CO2-TPD, pyridine-IR, and NH3-TPD analyses reveal that the catalytic performance is significantly affected by an acid–base property. Obtaining a high catalytic performance necessitates a cooperation of enough acidic sites and basic sites.
研究领域:
催化化学
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可再生资源与环境科学
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DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
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2020
·
IF 5.006
Xuefei Wang,Yong Men,Jinguo Wang,Shuang Liu,Qiaoling Song,Mei Yang
Catalytic transformation of ethanol has been studied over a series of MgO-SiO 2 composite catalysts with different ZnO loadings. Vast differences in product selectivity are obtained by varying ZnO loadings in enabling the control over product distribution. Our results reveal that MgO-SiO 2 composite catalysts with low ZnO loadings tend to show an enhanced efficiency for C C bond coupling and exceptionally high selectivity to 1,3-butadiene whereas the high ZnO loadings favor the formation of acetaldehyde via dehydrogenation. Thorough analysis of characterization results via XRD, BET, IR, TPD, and 29 Si MAS NMR indicates that ZnO loading influences the extent of MgO and SiO 2 interaction during preparation, and the surface acid-base chemistry, which were both found to correlate with the catalytic performance. This study proposes that the Mg O Si interfacial structure formed by the strong MgO and SiO 2 interaction at low ZnO loadings is of prime importance for the formation of 1,3-butadiene, benefiting from the desirable properties of balanced dehydrogenation and C C bond coupling while excess ZnO loadings destroy the Mg O Si interfacial bonds over the MgO-SiO 2 composite catalysts, which are the key structures required for C C bond growth.
研究领域:
催化化学
·
材料科学
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产品关联
DOI
高影响因子
CATALYSIS LETTERS
·
2021
·Vol. 152
·期 8
·2524-2532
·
IF 3.186
Jiang Haoxi,Jiang Angjiong,Gao Qiang,Yang Guochao,wang Lingtao
In this work, Ta was firstly reported as an efficient promoter of MgO–SiO 2 for the conversion of ethanol and acetaldehyde to 1,3-butadiene. The doping of Ta into MgO–SiO 2 forms Ta–O–Si bonds and generates more strong Lewis acid sites, which not only promote the aldol condensation reaction but also significantly facilitate the Meerwein–Ponndorf–Verley reduction, the total conversion around 80% which drops to 65% after 24 h. In addition, the catalyst showed desirable stability in 24 h long-term stability evaluation, the selectivity remained stable at 80%. Graphic Abstract
研究领域:
催化化学
·
材料科学
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DOI
高影响因子
ChemCatChem
·
2024
·
IF 3.8
Mingwei Wang,Zhen Shi,Zhiquan Yu,Shushuang Li,Zhixin Zhang,Feng Wang
Graphical The HCHO-acetaldehyde condensation is a typic aldol reaction and a critical step to produce 1,3-propanediol from methanol and ethanol. The cross condensation of HCHO and acetaldehyde to acrolein has been conducted over MgO/SiO 2 catalyst, which shows the synergistic catalysis by the acidic sites (Mg-O-Si structure) and basic sites (Mg-O-Mg structure) for activation of HCHO and acetaldehyde, respectively. Acid-base synergistic catalysis greatly enhances the performance of MgO-based catalysts in the Aldol condensation. In this paper, the effect of acid-base strength/concentration/proportion and the synergistic catalysis on the performance of cross condensation between HCHO and acetaldehyde were studied. The NH 3 /CO 2 -TPD results indicated that the weak acidic sites combined with the medium basic sites were beneficial for the cross condensation of formaldehyde and acetaldehyde. The loading of MgO nanocrystals on SiO 2 induced the generation of new acidic sites (Mg-O-Si). Combined with the inherent basic sites (Mg-O-Mg) and Mg-O-Si, the acid-base bifunctions sites could catalyze the cross condensation of HCHO and acetaldehyde synergistically. The appropriate proportion of acidic/basic sites (10/1) was critical for the cross condensation in the presence of vast water in formalin. The effect of reaction parameters, including molar ratio of substrates, reaction temperature, linear velocity and weight hourly space velocity, were investigated for the cross condensation. The results showed that 10 wt% MgO/SiO 2 catalysts exhibited the highest catalytic activity (57.9% conversion of acetaldehyde and 84.3% selectivity of acrolein) under the optimal reaction parameters among the investigated catalysts. The catalytic performance of MgO/SiO 2 could be recovered after in situ regeneration in air to remove the carbon deposition.
研究领域:
化学工程
·
催化科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）