Assessing Hydrolysis Performance of Ce(OH)4@PIM-1 Composites Functionalized with Amidoxime, Aldoxime, and Carboxylate Groups Toward Dimethyl 4-Nitrophenylphosphonate, a Nerve Agent Simulant

In recent years, significant attention has been directed toward evaluating the reactivity of diverse polymers to gauge their catalytic activity against hazardous chemicals. Among these polymers, PIM-1 has emerged as an exceptional candidate due to its noteworthy attributes including high surface area, excellent solubility, and the capability to fine-tune the nitrile functional groups along its polymeric backbone. In this study, we explored the impact of different functional groups, such as amidoxime (AX), aldoxime (OX), and carboxylate (COOH), on the degradation of dimethyl 4-nitrophenylphosphonate (DMNP) in comparison to pure PIM-1 and their respective Ce(OH)4-loaded polymer composites. Remarkably, the PIM-1-AX analog exhibited the highest degree of catalytic activity (ca. 100%) among the functional groups investigated under 24 h, due to its high nucleophilicity, whereas under 1 h, Ce(OH)4@PIM-1-COOH outperformed other materials by displaying an initial hydrolysis rate of 0.058 μmol/s and a half-time of 0.38 min, on the account of its high Lewis acidity, stemming from the Ce4+ coupled with the Bronsted carboxylic acid. Overall, the findings of this study highlight the influence of the Bronsted and Lewis acid pairs in promoting the DMNP degradation kinetics, providing an alternative pathway to the commonly used nucleophilic substitution method.