Kinetic and experimental study of Mn(III) acetylacetonate for green hypergolic ignition in HTP/Kerosene systems

• Mn(III)AA catalyzes green HTP/kerosene hypergolic ignition. • IDTs as low as 25 ms achieved; initial fuel temperature expands envelope. • Kinetic analysis reveals efficient catalysis (low E a ). • Pre-exponential factor shows diminishing returns with catalyst. • Catalyst strongly accelerates chemical ignition phase. The transition towards non-toxic, high-performance spacecraft propulsion has positioned highly concentrated hydrogen peroxide (HTP) and kerosene as a leading green propellant combination. However, achieving reliable hypergolic ignition in non-polar hydrocarbons remains a critical challenge due to significant physical mixing limitations and high chemical activation barriers. This study investigates the catalytic efficacy of Manganese(III) acetylacetonate (Mn(III)AA) dissolved in aviation-grade kerosene to enable rapid hypergolicity with 98% HTP. High-speed imaging and thermal diagnostics were employed to map the ignition delay time (IDT) across a range of catalyst loadings (0.5–10 wt%) and oxidizer-to-fuel ratios (4.5–7.5). The results demonstrate that Mn(III)AA is highly effective, achieving a minimum IDT of 25 ms at 50°C. Kinetic analysis revealed a significant reduction in apparent activation energy (9 to 14 kJ/mol), accelerating the chemical reaction rate until the system becomes limited by physical mixing processes. Notably, a non-linear performance trend was observed, where catalyst additions beyond 5 wt% yielded diminishing returns, suggesting a saturation threshold for practical engine design. These findings establish Mn(III)AA as a viable, high-efficiency additive for green bipropellant systems.