Guimei Yuan

Metathesis of 1-butene and 2-butene to propene over Re2O7 supported on macro-mesoporous γ-alumina prepared via a dual template method

Abstract Macro-mesoporous γ-alumina support (MMA) was prepared by a sol-gel route in aqueous medium using pseudo-boehmite as aluminum source and polystyrene microspheres and Pluronic P123 as hard and soft dual templates, respectively. MMA had a BET specific surface area of about 259 m2·g−1, total pore volume of about 1.61 cm3·g−1, macropore diameter of about 102 nm, and mesopore diameter of about 14 nm. Re2O7/MMA and conventional Re2O7/Al2O3 were prepared by a incipient-wetness impregnation method, and their catalytic performances in the metathesis of 1-butene and 2-butene were tested in a fixed-bed tubular reactor. The result showed that Re2O7/MMA possessed higher activity and far longer working life-span than conventional Re2O7/Al2O3.

Preparation of mesoporous alumina with large pore size and their supported rhenium oxide catalysts in metathesis of 1-butene and 2-butene to propene

Abstract Mesoporous γ-aluminas with large pore size (up to 19 nm, denoted as MA19) are prepared from dispersed pseudo-boehmite using pluronic P123 as template. It is found that these mesoporous alumina supported rhenium oxide catalysts were more active and have far longer working life-span in gas-phase metathesis of 1-butene and 2-butene to propene than rhenium oxide on conventional alumina with small pore size (5 nm). At 60°C and atmospheric pressure with WHSV= 1 h −1 , the similar stable conversions of butene (ca. 55%) for all the 13 wt% Re 2 O 7 /alumina catalysts were obtained near the chemical equilibrium, and the stable working life-spans of Re 2 O 7 /MA19 were far longer than that of Re 2 O 7 /Al 2 O 3 , being about 70 h and 20 h, respectively.

Synthesis of ZSM-5 and its application in butylene catalytic cracking

Abstract The template-free ZSM-5 was prepared by hydrothermal synthesis and then modified by tetramethoxysilane (TMOS). The structure, morphology, and acidity of all samples were studied by various techniques, such as XRD, SEM, 29 Si MAS NMR, 27 Al MAS NMR, NH 3 -TPD, BET and UV-vis DRS. Comparing with the zeolites synthesized by traditional method, the template-free ZSM-5 exhibited the analogical acidity, morphology and structure, but obvious difference in acid distribution. Due to the absence of the structure directing agent, the template-free ZSM-5 possessed more acid sites situated at pore channels of catalyst and less acid sites stayed at the intersection of straight and sinusoidal channels. Consequently, the shape selectivity enhanced significantly. After TMOS modification, the non-shape acid sites located at the external surface were covered by a single SiO 2 layer. The template-free ZSM-5 achieved the highest total yield of ethylene and propylene, longest working life-span and lowest level of coke deposition among the studied catalysts, ascribing to the suppression of the side reactions.

Modification and Photocatalytic Activity of TiO 2 Inverse Opal Membranes: Modification and Photocatalytic Activity of TiO 2 Inverse Opal Membranes

利用液相沉积技术对TiO 2 反蛋白石结构材料进行表面处理, 通过在反Opal孔内表面生成一层TiO 2 颗粒, 增加其有效比表面积。以降解罗丹明B为探针反应, 研究了经LPD表面处理之后的TiO 2 反Opal材料的光催化活性, 考察了硼酸用量对TiO 2 反Opal材料表面形貌和光催化活性的影响。结果表明LPD处理之后的TiO 2 反Opal膜比未处理的膜具有更高的光催化活性, 硼酸用量在0.0183 g/mL时处理的TiO 2 反Opal膜具有最高的光催化活性, 相比未处理的膜催化剂活性提高了6倍。利用液相沉积技术对TiO 2 反蛋白石结构材料进行表面处理, 通过在反Opal孔内表面生成一层TiO 2 颗粒, 增加其有效比表面积。以降解罗丹明B为探针反应, 研究了经LPD表面处理之后的TiO 2 反Opal材料的光催化活性, 考察了硼酸用量对TiO 2 反Opal材料表面形貌和光催化活性的影响。结果表明LPD处理之后的TiO 2 反Opal膜比未处理的膜具有更高的光催化活性, 硼酸用量在0.0183 g/mL时处理的TiO 2 反Opal膜具有最高的光催化活性, 相比未处理的膜催化剂活性提高了6倍。