A series of Fe 2 O 3 doped SBA-15 materials were prepared via an equivalent-volume impregnation method. The resultant Fe 2 O 3 -containing SBA-15 materials showed good performance in phenol methylation . Under the same conditions, the mesoporous catalyst with 5 wt.% Fe 2 O 3 showed the superior catalytic activity to that of pristine α -Fe 2 O 3 even at lower reaction temperature (320 °C vs. 350 °C). The elevated catalytic activity observed for the mesoporous catalyst could be due to high level dispersion of Fe 2 O 3 species in the mesoporous framework. Furthermore, the mesoporous catalyst possessed long lifetimes, which could be used continuously for 2000 h without significant loss of activity.
A series of highly active and ortho -position selective catalysts based on (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts were proposed for the C -methylation of phenol with methanol. The (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts were synthesized by coprecipitation method of Fe and V elements and microwave drying. The chemical composition, material structure, acid-base properties, and structure-activity relationship of (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts were systematically analyzed by the techniques of XRD, XPS, TEM, N 2 adsorption-desorption, Raman, UV-Vis, ESR, NH 3 /CO 2 -TPD and Pyridine-IR. The (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts have the double advantages of high activity and high stability for the methylation of phenol due to the high BET surface area, large total pore volume, dispersive active sites and enhanced acid-base property. o -cresol and 2,6-xylenol were the main products, and nearly 100% selectivity to the ortho -position of phenol and 90% selectivity to o -cresol were obtained. Furthermore, the (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts possess long lifetime over 2500 h and high activity at a weight hourly space velocity of 1.6 h −1 compared with the microwave-dried α-Fe 2 O 3 catalyst. The doping of vanadium improves the activity and stability of α-Fe 2 O 3 catalyst, which attributes to the modification of catalyst structure, especially the improvement of acid-base centers and oxygen vacancy. Recently the (α-Fe 2 O 3 ) 1- x (V 2 O 5 ) x catalysts have been stably and efficiently applied in industry for the methylation of phenol.
Yang Qin,Xubin Zhang,Fumin Wang,Yongwang Li,Zhiwei Zhang,Zheng Wang,Qingzhao Liu,Bingxin Zhu,Junqi Zhang,Zhiqiang Qin,Tongxue Zhang,Hongyu Wang
Iron oxides are considered ideal catalysts for the ortho C-alkylation of phenol and methanol due to their favorable properties, so the simple synthesis of high-performance iron oxides will be of great significance. Different iron oxides catalysts are synthesized by direct thermal decomposition of five different iron precursors, and the effects of calcination temperature and atmosphere on their catalytic performance are analyzed. Characterization and experiments indicate that the total acidic content in the catalyst show a good correlation with its catalytic performance. The catalyst synthesized from iron citrate, with a high total acidic content, exhibits the best catalytic performance. The effects of reaction conditions are investigated. With the temperature increases, the conversion of phenol and the selectivity of 2,6-xylenol both show a “volcanic” trend. Unlike most previous reports, the molar ratio is positively correlated with catalytic performance, and the competitive adsorption of phenol and methanol is virtually negligible on the catalyst. Under the optimized reaction conditions, the conversion of phenol can achieve 99.4 % with a selectivity of 93.7 % to 2,6-xylenol. Finally, the causes of catalyst deactivation are analyzed and explained. The catalyst exhibits competitive catalytic performance and provides a novel approach for the efficient methylation of phenol.
危险品化学品经营许可证（带存储）