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本文对传统共沉淀法进行改进,成功制备出高表面积(383.87 m2/g)高分散度(42.74%)的新型Cu-O-Al骨架结构催化剂,表征结果表明,改进后的制备方法可以有效增大催化剂比表面积和孔容,并使得催化剂上铜物种的颗粒更小、分散度更高,进而表现出较高的催化活性。同时由于形成了Cu-O-Al骨架结构,可以显著抑制铜物种的移动,进而提高催化剂的稳定性。本文以成本较低的空气作为氧源,在典型催化剂(CuAl3)上反应温度300 ℃、较高液时空速2 h-1下,MOP最佳转化率为85.2%,MOA选择性为55.7%,且稳定运行32 h,而该空速下传统浸渍法制备的催化剂已基本无催化活性。 相似文献
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以硝酸铜、硝酸锰、硝酸铝和碳酸钠为原料,通过共沉淀法制备了不同Mn含量的Cu-Mn-Al催化剂。采用BET,XRD,SEM,TEM,H2-TPR和NH3-TPD等对催化剂进行了表征,在固定床反应器上考察了催化剂对丙二醇单甲醚直接脱氢制备甲氧基丙酮反应活性的影响。结果表明:Mn含量对Cu-Mn-Al催化剂理化性质有较大影响。适量添加Mn能够促进Cu的分散,改变催化剂还原性能,降低催化剂表面酸性。当n(Cu):n(Mn):n(Al)=2.0:3.5:1.0时,Cu-Mn-Al催化剂表面酸量低,具有较低还原温度。在反应温度260℃、常压、进料组成为含5%(质量分数)水的丙二醇单甲醚溶液、液时空速为2.5h-1的条件下,该催化剂上丙二醇单甲醚转化率可达61.57%,甲氧基丙酮选择性可达96.83%,且副产物丙酮选择性低,为1.20%。 相似文献
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Methoxyacetone was transaminated with benzylamine to methoxyisopropylamine over a Pd/SiO2 catalyst modified with Lalaninol or Lphenylalaninol covalently anchored to the surface of the support via an organosilicon spacer group. In the first step of transamination a Schiff base was formed from the ketone and benzylamine, and then it was hydrogenated in the second step on the chirally modified Pd/SiO2 catalysts to an asymmetric secondary amine (Nbenzylmethoxyisopropylamine). In the third step the hydrogenolysis of the asymmetric secondary amine resulting in methoxyisopropylamine and toluene was carried out over a 10 wt% Pd/C catalyst. The highest enantiomeric excess of (S)methoxyisopropylamine was observed in cyclohexane (ee = –20–21%) using anchored Lalaninol as a chiral modifier. 相似文献
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