MICROPOROUS AND MESOPOROUS MATERIALS
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2014
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IF 3.209
Ben Qi,Lan-Lan Lou,Yanbing Wang,Kai Yu,Ying Yang,Shuangxi Liu
Manganese containing mesoporous materials Mn-MCM-41 were prepared by template-ion exchange (TIE), in situ reduction (ISR), direct hydrothermal (DHT) and wetness impregnation (WI) methods. The samples were characterized by XRD , N 2 adsorption–desorption, HR-TEM, TG, UV–Vis, H 2 -TPR and ESR techniques, which illustrated that the definite structure of the MCM-41 was retained after introducing Mn into MCM-41 by different method. The catalytic activity and selectivity of the Mn-MCM-41 in the epoxidation of styrene with 30% H 2 O 2 as an oxidant agent were explored. The TIE catalysts showed the highest activity but Mn 2+ was leached during the reaction. The ISR catalysts exhibited high activity for epoxidation of styrene. Furthermore, recycling studies proved the ISR catalysts as heterogeneous catalysts , which did not lose the catalytic activity after four recycles appreciably. However, the DHT and WI catalysts showed poor performance in the catalytic epoxidation of styrene. Various parameters such as different reaction molar ratio of H 2 O 2 /styrene, catalyst amount, and kinds of solvents were studied to optimize the reaction conditions.
研究领域:
催化化学
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材料化学
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有机合成
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多相催化
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环境友好氧化过程
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
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2021
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IF 5.909
Guangrong Liu,Mingxin Chen,Xin Jin,Chuangfu Song,Feifei He,Qiang Huang
In this work, 12-tungstophosphoric acid-TiO 2 composite (PTA-TiO 2 ) catalysts were fabricated by a simple method of impregnation-heat treatment. PTA-TiO 2 composites were characterized by XRD , XPS, TG/DSC, FTIR , UV−vis diffuse reflectance spectra and N 2 adsorption–desorption measurements. The results showed that the heat treatment temperature (200–500 °C) significantly affected the composition and structure of the composite. The higher calcination temperature could destroy the Keggin structure of PTA. The PTA-TiO 2 catalyzed oxidation of cyclohexene by H 2 O 2 to adipic acid demonstrated that the Keggin structure of PTA was critical to the catalytic activity of PTA-TiO 2 . Furthermore, under the photo-thermal catalytic condition, the reaction system showed higher cyclohexene conversion and adipic acid yield. A synergistic effect between the photo- and thermal approach was noticed in the PTA-TiO 2 catalyst prepared at 200 °C (PTA-TiO 2 (200)). Based on the experimental data, a thermocatalysis-dominated but photocatalysis-promoted mechanism was proposed to explain the improvement in catalytic efficiency. The catalyzed oxidation of cyclohexene with photo-thermal synergy enables utilization of sunlight and offers a novel perspective for the manufacture of adipic acid.
研究领域:
催化
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化学工程
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光化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2020
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IF 2.627
Xianfeng Liu,Fu Yang,Shuying Gao,Bo Shao,Shijian Zhou,Yan Kong
Design and synthesis of low cost and efficacious industrial catalyst for the oxidation of styrene has been an important research project. Herein, ZSM-5 zeolite containing tetrahedral vanadium (V) and Brønsted acid sites (V-H-ZSM-5) was prepared, and identified by characterizations such as XRD, SEM, UV–vis, NH 3 -TPD, H 2 -TPR N 2 -adsorption/desorption and FTIR. V-H-ZSM-5 performed extremely enhanced catalytic activity for the oxidation of styrene with 30% H 2 O 2 at 40 °C. Moreover, in-situ FTIR spectrum was used to investigate the catalytic mechanism. The results demonstrate that Brønsted acid site could not only increase the adsorption concentration of styrene in the micropores of V-H-ZSM-5 via the π complex interaction between double bond of styrene and Brønsted acid sites, but also increase the oxidation potential of H 2 O 2 . The synergetic action of tetrahedral vanadium (V) and Brønsted acid enhanced the catalytic activity for the oxidation of styrene with 30% H 2 O 2 . Impressively, V-H-ZSM-5 performed high reusability within five runs at a low reaction temperature (40 °C) for the first time.
研究领域:
催化化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS TODAY
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2022
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IF 6.562
Xinchao Liu,Huan Liu,Lihua Chen,Baolian Su,Xinhuan Lu,Qinghua Xia,Dan Zhou
Herein, highly efficient Ti-containing zeolite catalyst (Ti/Al-HSZ) has been prepared by an active catalysis species surface implanting strategy (ACS-SIS) through the combination of precedent acid treatment and subsequent recrystallization. Compared with commercial titanosilicate zeolite catalysts and Ti-HSZ catalyst synthesized by one-step method, Ti/Al-HSZ- c - 3.5d-AT catalyst presents highly enhanced catalytic activity and turnover number values in the epoxidation of linear and cycloalkenes by using 30% H 2 O 2 as oxygen agent under mild reaction conditions. Particularly for the conversion of bulky linear alkene and cycloalkene (1-dodecene and cycloheptene), the catalytic activity of Ti/Al-HSZ- 4M‐3.5d‐AT can attained more than three times than that over Ti-HSZ- 3.5d-AT . Based on systematical comparison and analysis, on one hand, the excellent catalytic performance of Ti/Al-HSZ is ascribed to its unique hollownest morphology that acts as ideal reaction space by providing with plenty of hierarchical porous structure and high external surface, which is beneficial for the diffusion and mass transfer of bulky substrate. On the other hand, the high content of active open Ti species locating on the surface of catalyst is particularly beneficial for the formation of transition state to accelerate the epoxidation reaction. Not only the Ti source utilization rate but also the Ti open incorporated rate of Ti/Al-HSZ- 4M‐3.5d‐AT prepared by ACS-SIS is much higher than that of Ti-HSZ prepared by one-step hydrothermal synthesis route. The effects of acid treatment and recrystallization on the zeolite framework, morphology, chemical composition, and Ti coordination states have been thoroughly discussed. The ACS-SIS is believed to be an effective route to construct excellent solid heterogeneous catalyst to meet the urgent need of green chemistry for sustainable development.
研究领域:
催化
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材料科学
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化学工程
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绿色化学
✓ 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）