ABSTRACT The development of heterogeneous catalysts remains a major focus due to their industrial importance and potential in emerging chemical processes. Mesoporous silica materials, particularly SBA‐15, offer advantages as catalyst supports because their surface silanol groups act as intrinsic catalytic sites and allow for controlled functionalization. However, a limited understanding of structure–property relationships often restricts the optimal design of such systems. This study examines how solvent choice influences the grafting density of catalytic ligands on SBA‐15 and the resulting catalytic performance. N‐(2‐aminoethyl)‐3‐aminopropyltrimethoxysilane (diamine) and 2‐(diphenylphosphino)ethyltriethoxysilane (PPh 2 ) were grafted onto SBA‐15 using toluene or 2‐propanol, followed by coordination with Fe(III) and evaluation in epoxide ring‐opening reactions. Elemental analysis revealed that diamine‐functionalized materials incorporated 15–20 times more ligand than PPh2‐functionalized analogues. Despite their lower loading, PPh2‐based catalysts exhibited roughly twice the activity reduction, resulting in significantly higher ligand‐normalized turnover rates (up to 113 h −1 ). In contrast, diamine systems provided the highest Fe‐normalized activity (up to 69 h −1 ), indicating improved metal stabilization. Additionally, 2‐propanol consistently produced more active catalysts than toluene. Overall, the results demonstrate that solvent and ligand selection strongly govern metal accessibility and ligand efficiency, enabling the rational design of cost‐effective Fe–SBA‐15 catalysts.
Jaffar et al. (Thu,) studied this question.