scholarly journals Catalytic Performance of Ce-modified MCM-68 Zeolite in the Dimethyl Ether-to-Olefin Reaction: Impact of High Calcination Temperature

2017 ◽  
Vol 46 (9) ◽  
pp. 1434-1437 ◽  
Author(s):  
Qiao Han ◽  
Kizuku Enoeda ◽  
Satoshi Inagaki ◽  
Yoshihiro Kubota
Catalysts ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 354
Author(s):  
Khadijah H. Alharbi ◽  
Ali Alsalme ◽  
Ahmed Bader A. Aloumi ◽  
Mohammed Rafiq H. Siddiqui

Oxidation is an important organic transformation, and several catalysts have been reported for this conversion. In this study, we report the synthesis of mixed metal oxide CuxZnyO, which is prepared by a coprecipitation method by varying the molar ratio of Cu and Zn in the catalytic system. The prepared mixed metal oxide CuxZnyO was evaluated for catalytic performance for toluene oxidation. Various parameters of the catalytic evaluation were studied in order to ascertain the optimum condition for the best catalytic performance. The results indicate that aging time, calcination temperature, reaction temperature, and feed rate influence catalytic performance. It was found that the catalyst interfaces apparently enhanced catalytic activity for toluene oxidation. The XRD diffractograms reveal the crystalline nature of the mixed metal oxide formed and also confirm the coexistence of hexagonal and monoclinic crystalline phases. The catalyst prepared by aging for 4 h and calcined at 450 °C was found to be the best for the conversion of toluene to benzaldehyde while the reactor temperature was maintained at 250 °C with toluene fed into the reactor at 0.01 mL/min. The catalyst was active for about 13 h.


2008 ◽  
Vol 9 (10) ◽  
pp. 2059-2062 ◽  
Author(s):  
Ji Chul Jung ◽  
Howon Lee ◽  
Heesoo Kim ◽  
Sunyoung Park ◽  
Young-Min Chung ◽  
...  

2013 ◽  
Vol 22 (5) ◽  
pp. 769-777 ◽  
Author(s):  
Yu Sang ◽  
Hongxiao Liu ◽  
Shichao He ◽  
Hansheng Li ◽  
Qingze Jiao ◽  
...  

2013 ◽  
Vol 26 (2) ◽  
pp. 220-224 ◽  
Author(s):  
Xue Zhang ◽  
Yu‐ping Li ◽  
Song‐bai Qiu ◽  
Tie‐jun Wang ◽  
Long‐long Ma ◽  
...  

Author(s):  
Yue Teng ◽  
Ke Yao ◽  
Wenbin Song ◽  
Yongjun Sun ◽  
Haoliang Liu ◽  
...  

Cu-Mn-Ce@γ-Al2O3 was prepared by incipient wetness impregnation and used to catalyze ozonation in a coal chemical wastewater-biotreated effluent. The preparation factors that considerably affected the catalytic performance of Cu-Mn-Ce@γ-Al2O3, specifically metal oxide loading percentage, calcination temperature, and calcination time, were examined. The catalyst was characterized by scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction, and Brunauer-Emmett-Teller analysis. The optimal catalytic ozonation operating parameters, such as ozone dosage, catalyst dosage, pH, and reaction time, were also investigated. Results showed that an optimized catalyst consisted of 17.0% CuO, 3.0% MnO2, and 2.0% CeO2 (wt.%). The optimal calcination temperature and calcination time were 600 °C and 5 h. The optimal catalytic ozonation operating parameters, including ozone dosage, catalyst dosage, pH, and reaction time, were 7, 80.0 mg/L, 20.0 mg/L, 7 and 50 min, respectively. The COD removal of biotreated effluent increased to 61% under these optimal operating conditions. Meanwhile, ozonation alone resulted in only 20% removal. This work proposes the use of easily available Cu-Mn-Ce@γ-Al2O3 catalyst and might drive the advancement of catalytic ozonation for chemical wastewater purification.


2019 ◽  
Vol 55 (8) ◽  
pp. 1048-1051 ◽  
Author(s):  
Xiaobo Feng ◽  
Jie Yao ◽  
Hangjie Li ◽  
Yuan Fang ◽  
Yoshiharu Yoneyama ◽  
...  

EU-12 zeolite was discovered to posses unreported catalytic performance for carbonylation reaction converting dimethyl ether to methyl acetate.


2011 ◽  
Vol 66-68 ◽  
pp. 1404-1409 ◽  
Author(s):  
Rui Zhi Chu ◽  
Zhong Cai Zhang ◽  
Ya Fei Liu ◽  
Xian Liang Meng ◽  
Zhi Min Zong ◽  
...  

A series of Pd/γ-Al2O3 catalysts with different additons of Pd were prepared by impregnation. The effect of calcination condition and Pd loading on catalytic performance of catalysts for one-step dimethyl ether synthesis has been investigated. The physic-chemical performance and structure of Pd/γ-Al2O3 catalysts were characterized by CO-TPD, TGA and nitrogen physisorption. The results show that the dispersion of Pd and the amount of adsorbration on the CO-bridge of Pd could be increased to by the moderate microwave heating on the catalysts, and the catalyst performance can be improved. But a large number of surface acidic sites of Pd/γ-Al2O3 are covered by highly fragmented Pd-grain, it causes DME selectivity reduced. And the excessive Pd can reduce the samples’ surface acid, decrease the dispersion of the metal Pd and block up the pore of γ-Al2O3. The CO conversion rate and DME space-time yield could reach 60.1% and 28.76 mmol·g-1·h-1 respectively at 2% Pd loading, at this time Pd/γ-Al2O3 has a high Pd activity surface and ideal acid sites.


2011 ◽  
Vol 77 (16) ◽  
pp. 5629-5634 ◽  
Author(s):  
Nhung Thi Tuyet Le ◽  
Hirofumi Nagata ◽  
Mutsumi Aihara ◽  
Akira Takahashi ◽  
Toshihiro Okamoto ◽  
...  

ABSTRACTThere is an increasing interest in the application of photocatalytic properties for disinfection of surfaces, air, and water. Titanium dioxide is widely used as a photocatalyst, and the addition of silver reportedly enhances its bactericidal action. However, the synergy of silver nanoparticles and TiO2is not well understood. The photocatalytic elimination ofBacillus atrophaeuswas examined under different calcination temperatures, dip-coating speeds, and ratios of TiO2, SiO2, and Ag to identify optimal production conditions for the production of TiO2- and/or TiO2/Ag-coated glass for surface disinfection. Photocatalytic disinfection of pure TiO2or TiO2plus Ag nanoparticles was dependent primarily on the calcination temperature. The antibacterial activity of TiO2films was optimal with a high dip-coating speed and high calcination temperature (600°C). Maximal bacterial inactivation using TiO2/Ag-coated glass was also observed following high-speed dip coating but with a low calcination temperature (250°C). Scanning electron microscopy (SEM) showed that the Ag nanoparticles combined together at a high calcination temperature, leading to decreased antibacterial activity of TiO2/Ag films due to a smaller surface area of Ag nanoparticles. The presence of Ag enhanced the photocatalytic inactivation rate of TiO2, producing a more pronounced effect with increasing levels of catalyst loading.


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