A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromati...A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromatics(MTA) were compared with HZSM-5@SiO_2. The silica shells of these two samples can both reduce the acid sites of HZSM-5, and consequently can decrease the formation of coke on the catalyst. However, in the ordered mesoporous SBA-15 shell the aromatics and the coke precursors could diffuse more effectively than in the amorphous SiO_2 shell; therefore, in the MTA reaction catalyzed by HZSM-5@SBA-15 composite a higher BTX selectivity and a longer catalyst cycle length were observed. The cycle length of HZSM-5@SBA-15 was by 50 h longer than that of HZSM-5@SiO_2, and under this situation the selectivity of BTX still reached 56%.展开更多
采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子...采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子筛催化剂的甲醇转化率为94.93%,对二甲苯选择性为45.46%。惰性SBA-15介孔分子筛抑制了ZSM-5外表面酸性,提高了对二甲苯的选择性。展开更多
Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a...Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a microwave reactor. The prepared catalysts were characterized by various techniques (XRD, N2</sub> physisorption at 77 K, SEM, TEM and NH3</sub>-TPD). The obtained results reveal that despite the differences in their structural and textural properties, the ZrO2</sub>, Al-SBA-15 and H-ZSM-5 supports show similar conversions. Doping supports with sulfonate species created hydrogen bonds between SO3</sub>H groups and increased the amount of weak acid sites, which enhanced the hydrolysis of hemicellulose. SO3</sub>H- ZSM-5 showed the highest catalytic activity followed by SO3</sub>H-SBA-15 while SO3</sub>H-ZrO2</sub> exhibited a poor conversion. Furthermore, the catalytic hydrolysis of the hemicellulose leads to several interesting products, such as formic acid, acetic acid, lactic acid and xylan. The correlation between the catalytic performances and the acidic properties of the different samples indicates that the best catalytic performances were obtained with the least acidic solids and especially when the density of strong acid sites decreases.展开更多
基金supported by the Program for Liaoning Excellent Talents in Universities,abbreviated as "LNET" (LJQ2015062)the Program for Science and Technology Agency of Liaoning Province (20170540585)+1 种基金the General Scientific Research Project of Liaoning Provincial Department of Education (L2015296, L2016018)the Science and Technology Planning Project of Fushun (FSKJHT201376)
文摘A core-shell HZSM-5@SBA-15 composite was prepared by the acidic sol-gel coating method using Pluronic P123 as the template. Its structure, properties, and catalytic performance in the conversion of methanol to aromatics(MTA) were compared with HZSM-5@SiO_2. The silica shells of these two samples can both reduce the acid sites of HZSM-5, and consequently can decrease the formation of coke on the catalyst. However, in the ordered mesoporous SBA-15 shell the aromatics and the coke precursors could diffuse more effectively than in the amorphous SiO_2 shell; therefore, in the MTA reaction catalyzed by HZSM-5@SBA-15 composite a higher BTX selectivity and a longer catalyst cycle length were observed. The cycle length of HZSM-5@SBA-15 was by 50 h longer than that of HZSM-5@SiO_2, and under this situation the selectivity of BTX still reached 56%.
基金supported by the National Natural Science Foundations of China(21476132,51536009,51406109 and 21506118)National High Technology Research and Development Program of China(863 program,2012AA101808)~~
文摘采用后合成法合成了ZSM-5–SBA-15微介孔复合分子筛,考察了m(ZSM-5)/m(SBA-15)、晶化时间、盐酸量、焙烧温度对烷基化催化性能的影响。在m(ZSM-5)/m(SBA-15)=0.2,晶化时间为18 h,盐酸量为20 m L,焙烧温度为550℃条件下,合成的复合分子筛催化剂的甲醇转化率为94.93%,对二甲苯选择性为45.46%。惰性SBA-15介孔分子筛抑制了ZSM-5外表面酸性,提高了对二甲苯的选择性。
文摘Sulfonated catalysts based on zirconia (SO3</sub>H-ZrO2</sub>), silica (SO3</sub>H-SBA-15) and zeolite (SO3</sub>H-ZSM-5) were studied in the catalytic hydrolysis reaction of hemicellulose in a microwave reactor. The prepared catalysts were characterized by various techniques (XRD, N2</sub> physisorption at 77 K, SEM, TEM and NH3</sub>-TPD). The obtained results reveal that despite the differences in their structural and textural properties, the ZrO2</sub>, Al-SBA-15 and H-ZSM-5 supports show similar conversions. Doping supports with sulfonate species created hydrogen bonds between SO3</sub>H groups and increased the amount of weak acid sites, which enhanced the hydrolysis of hemicellulose. SO3</sub>H- ZSM-5 showed the highest catalytic activity followed by SO3</sub>H-SBA-15 while SO3</sub>H-ZrO2</sub> exhibited a poor conversion. Furthermore, the catalytic hydrolysis of the hemicellulose leads to several interesting products, such as formic acid, acetic acid, lactic acid and xylan. The correlation between the catalytic performances and the acidic properties of the different samples indicates that the best catalytic performances were obtained with the least acidic solids and especially when the density of strong acid sites decreases.
