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Bu‐NENA (N‐butyl‐N‐nitratoethyl nitramine) base propellants have versatile qualities, such as, higher energy, reduced sensitivity, and enhanced mechanical properties. The evaporation of Bu‐NENA, which takes place in the propellant grains in the course of time, can reduce the physical properties of the propellants, weaken the propellant grains, cause the propellants to crack at stress‐concentrated points, and finally result in unfavorable increases or fluctuations of the burning rate and poor performance of the rocket motor. In this study, the evaporation of Bu‐NENA from a double base propellant was investigated using isothermal thermogravimetry. The results showed that the entire process of Bu‐NENA evaporation complied with the power law of evaporation rate with time. The values of kinetic parameters of Bu‐NENA evaporation were calculated: Evap=67.68 kJ mol−1 and Avap=1.57×105 s−1. In comparison, the values of NG (nitroglycerin) evaporation were determined: Evap=69.68 kJ mol−1 and Avap=1.33×106 s−1. The value of the activation energy of Bu‐NENA evaporation was close to that of NG, but the pre‐exponential factors differed by an order of magnitude. The evaporation of Bu‐NENA followed zero‐order kinetics at the early stage, and the enthalpy of Bu‐NENA evaporation was calculated to be 69.75 kJ mol−1 according to Langmuir and Clausius‐Clapeyron equations.

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To achieve maximum usage and economically upgrade light cycle oil, it is necessary to separate light cycle oil components into nonaromatic and aromatic fractions. A deep eutectic solvent composed of tetrabutylphosphonium bromide and levulinic acid exhibited excellent extraction performance in separating light cycle oil components. In this work, the mechanisms of deep eutectic solvent formation and light cycle oil separation are investigated using characterization analysis and molecular dynamics simulations. Both Fourier-transform infrared spectra and molecular dynamics simulation results indicate that the main driving force for deep eutectic solvent formation is hydrogen-bonding interactions between the Br − anion of tetrabutylphosphonium bromide and the carboxyl group (−COOH) of levulinic acid. On the other hand, while the TBP + cation of tetrabutylphosphonium bromide and the carbonyl group (−CO) of levulinic acid are less likely to contribute to deep eutectic solvent formation, they are more likely to interact with the aromatic ring of tetralin via CH−π and π−π interactions, respectively. The results suggest that each functional group of tetrabutylphosphonium bromide and levulinic acid plays an essential role either in deep eutectic solvent formation or in aromatic compound extraction, which provides insights into the mechanism of extractive separation of light cycle oil components using deep eutectic solvents.