Magnetic <scp>AlCl</scp> ₃ @Fe ₃ O ₄ ‐ <scp> SiO ₂ </scp> Nanocatalyst for Solvent‐Free Petroleum Resin Polymerization

ABSTRACT The separation and reusability of conventional acid catalysts such as AlCl 3 in petroleum resin polymerization remain major challenges, leading to environmental concerns and process inefficiencies. This study introduces the first application of a magnetically separable core‐shell nanocatalyst, AlCl 3 @Fe 3 O 4 ‐SiO 2 , for the solvent‐free polymerization of pyrolysis gasoline to produce petroleum resin as a proof‐of‐concept demonstration toward more sustainable processing. The catalyst was synthesized via immobilization of AlCl 3 on functionalized silica‐coated magnetic nanoparticles and comprehensively characterized using BET, DLS, EDAX, FESEM, FT‐IR, ICP, TEM, TGA, VSM, and XRD. Evaluation in petroleum resin polymerization utilized pyrolysis gasoline feedstock under optimized solvent‐free conditions (20°C, catalyst‐to‐feed ratio: 1.13 wt.%, residence time: 86 min). The nanocatalyst demonstrated high catalytic performance, achieving product yields exceeding 90% with molecular weights ranging 3060–3322 g/mol and softening points between 214°C and 251°C. Key advantages include rapid reaction completion (~90 min), elimination of organic solvents, and convenient magnetic separation enabling six consecutive reuses without substantial activity degradation. Control experiments confirmed that the core‐shell structure provides enhanced stability and accessibility compared to homogeneous AlCl 3 or physical mixtures, with the covalent immobilization of AlCl 3 on the functionalized silica surface being essential for stable catalytic activity and reusability. This work provides a promising laboratory‐scale strategy for catalyst recovery in petroleum resin production, reducing waste and enabling a step toward more sustainable manufacturing through magnetic separation technology.