Different structure amine-functionalized mesoporous silica catalysts for trichlorosilane disproportionation: catalytic performance and mechanism analysis

Trichlorosilane (TCS) disproportionation is a critical reaction for industrial production of electronic-grade dichlorosilane, yet its extensive application is severely limited by the lack of efficient and stable catalysts. Organic amine-functionalized materials have shown potential for this reaction. However, the correlation between amine structure and catalytic performance remains unclear. Herein, five amine-grafted catalysts, including three di-n-alkylamino-modified samples (DEA@AMS, DPA@AMS, DBA@AMS) with different alkyl chain lengths and two heterocyclic amino-modified materials (MOR@AMS, IM@AMS), were synthesized via a silane-coupling grafting strategy. The structure-dependent catalytic behaviors and intrinsic mechanisms were systematically investigated by experimental evaluation and DFT calculations. Experimental results demonstrate that IM@AMS delivered the best catalytic activity and thermal stability. Under optimal conditions (120 °C, 0.05 mmol-N/mL TCS, 50 min), TCS conversion reached 21.54 % and retained 18.60 % after 10 cycles, confirming its favorable reusability. DFT results indicate that the superior performance of IM@AMS originates from its unique electronic properties. The HOMO of pyridine-type N in the imidazole ring matches well with the LUMO of TCS. Meanwhile, IM@AMS possesses the most negative ESP value of −54.95 kcal/mol and the lowest reaction energy barrier of 0.42 eV. The electron-rich N active sites on IM@AMS preferentially interact with the positively charged Si atoms of TCS to generate SiCl 3 − intermediates, which effectively promotes the TCS disproportionation. The theoretical calculation results are in good agreement with the experimental catalytic data. This work clarifies the structure-performance relationship of amine-functionalized catalysts for TCS disproportionation and provides a feasible design strategy for the development of high-efficiency catalysts toward industrial TCS disproportionation applications.