| 以镁铝水滑石为前驱体制备复合氧化物催化丙酮气相缩合反应 |
| Acetone Gas Phase Condensation on Mg-Al Composite Oxides Catalysts Prepared via Mg-Al Hydrotalcites Precursor |
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| 摘要: 采用共沉淀-恒温晶化法制备了系列镁铝水滑石(Mg-Al-LDH)样品，对镁铝水滑石在500 ℃焙烧得到镁铝复合氧化物(Mg-Al-LDO)，采用IR、XRD、CO2-TPD、SEM及N2吸附-脱附等方法对Mg-Al-LDH和Mg-Al-LDO进行了表征。在温度250 ℃、液时空速1 h-1条件下，采用固定床对镁铝复合氧化物催化剂对丙酮缩合反应的性能进行微反活性评价。研究结果表明，晶化时间与镁铝复合氧化物的弱碱性位和强碱性位的密度相关。丙酮缩聚反应的主要产物为异佛尔酮(IP)和异丙叉丙酮(MO)，以及少量的异丙烯基丙酮、双丙酮醇，均三甲苯等。丙酮缩聚制备异佛尔酮的反应需要催化剂表面弱碱性位(Sw)与强碱性位(Ss)的协同作用，Sw与Ss需要匹配。晶化12 h得到的镁铝复合氧化物催化剂(LDO-12)的Sw/Ss=1.3，异佛尔酮(IP)选择性为65.3%，单程有效收率(IP+MO)为14.8%。 |
| 关键词: 镁铝水滑石 镁铝复合氧化物 异佛尔酮 丙酮缩聚 固体碱催化剂 |
| 基金项目: |
| Abstract: The Mg-Al-layered double oxides(Mg-Al-LDO) were prepared at 500 ℃ for 4 h through calcining the Mg-Al-layered double hydroxides(Mg-Al-LDH) from co-precipitation-constant-temperature-crystal method. The samples were characterized by IR, XRD, CO2-TPD, SEM and nitrogen-adsorption/desorption measurements. The acetone vapor-phase condensation reaction on Mg-Al-LDO catalysts were carried on fixed-bed micro-reactor at 250 ℃ and liquid hourly space velocity(LHSV) of 1 h-1. The results show that the density of weak and strong basic sites on Mg-Al-LDO are dependent on crystallization time of Mg-Al-LDH. The acetone condensation is catalyzed by basic sites and the obtained products are isophorone(IP), mesityl oxide(MO), isomesityl oxide and mesitylene. The catalysis reaction of acetone vapor-phase condensation for IP requires the synergistic effect of weak basic sites(Sw) and strong basic sites(Ss), and furthermore, the Ss must match with Sw in this catalysis reaction. The optimum Mg-Al-LDO catalyst is LDO-12(crystallization time=12 h) and its Sw /Ss raito is 1.3, the selectivity of IP is 65.3%, single-pass-yield of(IP+MO) is 14.8%. |
| Keywords: Mg-Al-LDH Mg-Al-LDO isophorone(IP) acetone oligomerization solid basic catalysts |
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| 王芳珠,杨 坤,柴永明,高鹏程.以镁铝水滑石为前驱体制备复合氧化物催化丙酮气相缩合反应[J].无机化学学报,2008,24(9):1417-1423. |
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