A large number of heterogeneous catalysts were tested in the aldol condensation of heptanal with cyclopentanone. There are many possible products from this aldol condensation, among which the most desired is 2-heptylidenecyclopentanone. As heterogeneous catalysts, the following were tested: caesium modified zeolites, functionalized MCM-41, and single (MgO, CaO, ZnO) and double (Mo–Si, Mg–Al, Zn–Al) metal oxides. The activity of modified zeolites and functionalized zeolites in this aldol condensation was low, whereas single and double metal oxides possessed high activity. The highest selectivity to the desired 2-heptylidenecyclopentanone (52%) was obtained using magnesium oxide as catalyst.

中文翻译：

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庚醛与环戊酮醛醇缩合反应中的多相催化剂

在庚醛与环戊酮的羟醛缩合中测试了大量非均相催化剂。这种羟醛缩合有许多可能的产物，其中最需要的是2-庚基环戊酮。作为非均相催化剂，测试了以下物质：铯改性沸石、功能化 MCM-41 以及单一（MgO、CaO、ZnO）和双（Mo-Si、Mg-Al、Zn-Al）金属氧化物。改性沸石和功能化沸石在这种羟醛缩合反应中的活性较低，而单金属和双金属氧化物具有较高的活性。使用氧化镁作为催化剂获得了对所需 2-庚基环戊酮 (52%) 的最高选择性。