Task-Specific Ferrocene-Based Ionic Liquid as a High-Efficiency and Antimigration Burning Rate Catalyst for Composite...

Catocene offers excellent catalytic activity in propellants but tends to migrate, easily leading to unstable combustion and safety hazards. To address this limitation, abundant ferrocene derivatives are synthesized by modifying the molecular polarity or enhancing interaction forces. However, most of these derivatives exist as solids and exhibit poor dispersibility in the propellant matrix. Therefore, we design a series of ferrocene-based room-temperature ionic liquids (F1-F4) as alternatives. Especially, F1 enhances weak interactions (such as hydrogen bonding and van der Waals forces) with ammonium perchlorate, thereby fundamentally suppressing migration. Moreover, owing to the retention of the active ferrocene unit, F1 is expected to exhibit excellent combustion catalytic performance comparable to catocene. Experiments confirmed that F1 could uniformly disperse within the compound solid propellant (CSP) and maintained no migration. Further, adding 2 wt % F1 increased the heat of explosion to 5373 J·g^-1 (15.6% rise) and promoted the burning rate to 6.54 mm·s^-1, approximately 4.0 times faster than the catalyst-free baseline (1.37 mm·s^-1) and 1.9 times faster than a catocene-containing CSP (3.47 mm·s^-1). The combustion temperature also rose from 1593.1 to 1972.3 °C. These results demonstrate the superior performance of F1, marking its potential as a promising burning rate catalyst substitute for catocene.