Unraveling the Heterogeneous Oligomerization Mechanism of Linear α-Olefins Catalyzed by Silica-Supported 12-Tungstophosphoric Acid

This study investigates the heterogeneous catalytic mechanism of long-chain linear α-olefin (LAO) oligomerization, which can be derived from biobased organic acids, over silica-supported 12-tungstophosphoric acid (TPA) catalysts. Higher TPA loadings improved the formation of C₃₂ oligomers due to higher density of medium + strong acid sites, emphasizing the importance of strong acid sites as active centers. The oligomerization followed a stepwise oligomerization pathway based on an Eley–Rideal mechanism. The process began with the dimerization of two 1-octene molecules to produce C₁₆, followed by the reaction of C₈ with C₁₆ to generate C₂₄. Notably, C₃₂ was preferentially formed through the coupling of two C₁₆ molecules, rather than through the reaction between C₂₄ and C₈ due to steric hindrance. Microkinetic analysis further revealed that the adsorption behavior of large oligomers significantly influenced overall oligomerization performance.