Green Synthesis of Hierarchical NaY Zeolite from Perlite for Enhanced Knoevenagel Condensation

• • The synthesized hierarchical NaY zeolite exhibits a framework SiO2/Al2O3 molar ratio of ~4.2, providing abundant basic sites essential for base-catalyzed Knoevenagel condensation, leading to higher benzaldehyde conversion than conventional NaY. • • Intercrystalline mesopores centered at ~20 nm are formed, which reduce diffusion limitations for bulky molecules, enhancing catalytic efficiency in condensation reactions. • • The green synthesis uses SMS-activated perlite as the sole Si and Al source, eliminating the need for costly organic templates and reducing energy consumption, offering a sustainable and economically viable production route. • • Optimal synthesis conditions (n(Na2O)/n(SiO2)=0.34, SDA content 8%, crystallization time 24 h) yield high-purity, highly crystalline NaY zeolite, demonstrating reproducibility and scalability potential.