سنتز و بررسي ساختار–كارايي‌كاتاليست‌هاي دوفلزي Pd–M (M = Ru, Ni, Co, Cu, Zn) تثبيت شده روي بستر TiO₂ در تبديل اتيل‌لوولينات به γ-والرولاكتون از طريق فرايند انتقال هيدروژن كاتاليستي

In this study, a series of TiO₂-supported bimetallic Pd–M catalysts (M = Ru, Ni, Co, Cu, Zn) were synthesized an‎d eva‎luated for the catalytic conversion of ethyl levulinate to γ-valerolactone (GVL). In order to determine the optimal operating conditions, key reaction parameters including temperature, reaction time, catalyst amount, substrate-to-hydrogen donor ratio, an‎d type of base were systematically investigated. The reactions were carried out in an aqueous medium using formic acid as the hydrogen donor. The optimized conditions were determined to be 35 mg of catalyst, 0.5 mL of ethyl levulinate, 3 mL of water, 3 mL of formic acid, an‎d 1.5 g of triethylamine at 210 °C for 6 h. The structural an‎d surface properties of the synthesized catalysts were characterized by FT-IR, FESEM, BET/BJH, an‎d ICP elemental analysis. BET/BJH results revealed a mesoporous structure with a suitable specific surface area, providing an appropriate platform for the uniform distribution of metallic nanoparticles. FESEM images further confirmed the surface morphology an‎d the effective deposition of metal species onto the TiO₂ support. Catalytic performance eva‎luation demonstrated that Pd–Ru/TiO₂ exhibited the highest activity under optimized conditions, achieving approximately 97% conversion an‎d yield toward γ-valerolactone. Moreover, Pd–Cu/TiO₂ showed a yield of about 93% under identical conditions, indicating an effective synergistic interaction between the metals an‎d highlighting the possibility of reducing noble metal content without significant loss of catalytic efficiency. Recycling experiments confirmed that the selec‎ted catalyst maintained satisfactory activity for at least two consecutive cycles. Overall, the main achievement of this work is the attainment of high GVL yield in the conversion of ethyl levulinate using catalysts with a total metal loading below 1 wt%, offering a significant economic an‎d practical advantage compared to many previously reported catalytic systems.

عليرضا نجفي چرمهيني

محمد ديناري

حسين توكل , سياوش كاظمي موحد