Zr(IV)-salphen-MCM-41 was prepared by immobilizing a zirconium(IV) Schiff base complex onto the surface of MCM-41. The structural properties of the heterogeneous catalysts were characterized by FT-IR, UV, TG, XRD, SEM, TEM, BET, EDX, CO₂-TPD, NH₃-TPD and ICP-OES. Studies on the catalytic properties of the immobilized Zr(IV)-Schiff base complexes were performed using the reduction and cyclization of ethyl levulinate (EL) to γ-valerolactone (GVL) with isopropanol as the hydrogen source. Various reaction parameters, such as temperature, reaction time, solvent and catalyst loading were carefully investigated. The optimal conditions (GVL yield up to 90%) involved the utilization of Zr(Salphen)-MCM-41 as the catalyst in isopropanol. The key to heightened reaction performance was the incorporation of the phenolate and aniline groups in the ligands of bound to Zr. This increased the basicity of the catalyst, which subsequently enhances the efficiency of the transfer hydrogenation reported herein. Meanwhile, the immobilized catalyst can be easily separated and efficiently recycled at least five times without significant loss of activity. Finally, we proposed a plausible reaction mechanism based on experimental and characterization data.

通过将锆（IV）席夫碱配合物固定在MCM-41的表面上来制备Zr（IV）-沙芬-MCM-41。通过FT-IR，UV，TG，XRD，SEM，TEM，BET，EDX，CO ₂ -TPD，NH ₃表征了多相催化剂的结构性能。-TPD和ICP-OES。利用异丙醇作为氢源，将乙酰丙酸乙酯（EL）还原并环化为γ-戊内酯（GVL），对固定化Zr（IV）-席夫碱配合物的催化性能进行了研究。仔细研究了各种反应参数，例如温度，反应时间，溶剂和催化剂负载量。最佳条件（GVL产率高达90％）涉及在异丙醇中利用Zr（Salphen）-MCM-41作为催化剂。提高反应性能的关键是在与Zr结合的配体中引入酚盐和苯胺基团。这增加了催化剂的碱性，其随后提高了本文报道的转移氢化的效率。同时，固定的催化剂可以很容易地分离，并且至少可以有效地循环使用五次，而不会显着降低活性。最后，我们根据实验和表征数据提出了一种合理的反应机理。