Synthesis of asymmetric [bis(imidazolyl)-BH2]+-cation-based ionic liquids as potential rocket fuels. Issue 60 (25th November 2021)

• Record Type: Journal Article
• Authors: Li, Xue; Zhang, Yin; Li, Hongping; Ding, Jing; Wan, Hui; Guan, Guofeng
• Is Part Of: RSC advances. Volume 11:Issue 60(2021)
• Page Start: 38040
• Page End: 38046
• Publication Date: 2021-11-25
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/d1ra07149a
• Languages: English
• ISSNs: 2046-2069

Abstract

Abstract : Asymmetric [bis(imidazolyl)-BH2] + -cation-based hypergolic ionic liquids are successfully synthesized, which possess a high density-specific impulse ranging from 305.4 to 357.8 s g cm −3, that make them promising candidates for rocket propellants. Abstract : As potential hypergolic fuels, hypergolic ionic liquids have attracted much attention since their development. Herein, a series of hypergolic ionic liquids based on asymmetric [bis(imidazolyl)-BH2 ] + cations were synthesized. The asymmetric structure of these hypergolic ionic liquids was further confirmed by NMR, infrared (IR), and high-resolution mass spectrometry-electron spray ionization (HRMS-ESI). Moreover, these hypergolic ionic liquids possess a high density of over 1.00 g cm −3, a comprehensive liquid range from −60 °C to 20 °C, and a density-specific impulse performance ranging from 305.4 to 357.8 s g cm −3, which is superior to that of unsymmetrical dimethylhydrazine. Remarkably, (1-allyl-1 H -imidazol-3-ium-1-yl)(1-methyl-1 H -imidazol-3-ium-1-yl) dihydroboronium dicyandiamide had the best ignition-delay time (18 ms), a high density (1.114 g cm −3 ), and a high value for heat of formation (400 kJ mol −1 /1.48 kJ g −1 ). This work provides the possibility of a promising and green hypergolic fuel as rocket propellant.