McCrary Parker D, Barber Patrick S, Kelley Steven P, Rogers Robin D
Center for Green Manufacturing and Department of Chemistry, The University of Alabama , Box 870336, Tuscaloosa, Alabama 35487, United States.
Inorg Chem. 2014 May 5;53(9):4770-6. doi: 10.1021/ic500622f. Epub 2014 Apr 9.
The dissolution of nido-decaborane, B10H14, in ionic liquids that are hypergolic (fuels that spontaneously ignite upon contact with an appropriate oxidizer), 1-butyl-3-methylimidazolium dicyanamide, 1-methyl-4-amino-1,2,4-triazolium dicyanamide, and 1-allyl-3-methylimidazolium dicyanamide, led to the in situ generation of a nonaborane cluster anion, B9H14, and reductions in ignition delays for the ionic liquids suggesting salts of borane anions could enhance hypergolic properties of ionic liquids. To explore these results, four salts based on B10H13 and B9H14, triethylammonium nido-decaborane, tetraethylammonium nido-decaborane, 1-ethyl-3-methylimidazolium arachno-nonaborane, and N-butyl-N-methyl-pyrrolidinium arachano-nonaborane were synthesized from nido-decaborane by reaction of triethylamine or tetraethylammonium hydroxide with nido-decaborane in the case of salts containing the decaborane anion or via metathesis reactions between sodium nonaborane (Na[B9H14]) and the corresponding organic chloride in the case of the salts containing the nonaborane anion. These borane cluster anion salts form stable solutions in some combustible polar aprotic solvents such as tetrahydrofuran and ethyl acetate and trigger hypergolic reactivity of these solutions. Solutions of these salts in polar protic solvents are not hypergolic.
巢式癸硼烷（B10H14）在自燃性离子液体（与适当氧化剂接触时会自燃的燃料）1-丁基-3-甲基咪唑二氰胺盐、1-甲基-4-氨基-1,2,4-三唑二氰胺盐和1-烯丙基-3-甲基咪唑二氰胺盐中的溶解，导致原位生成九硼烷簇阴离子[B9H14]−，并缩短了离子液体的点火延迟，这表明硼烷阴离子盐可增强离子液体的自燃性能。为探究这些结果，基于[B10H13]−和[B9H14]−合成了四种盐，即三乙铵巢式癸硼烷、四乙铵巢式癸硼烷、1-乙基-3-甲基咪唑蛛网式九硼烷和N-丁基-N-甲基吡咯烷鎓蛛网式九硼烷。对于含癸硼烷阴离子的盐，通过三乙胺或氢氧化四乙铵与巢式癸硼烷反应由巢式癸硼烷合成；对于含九硼烷阴离子的盐，则通过九硼烷钠（Na[B9H14]）与相应有机氯化物之间的复分解反应合成。这些硼烷簇阴离子盐在一些可燃极性非质子溶剂（如四氢呋喃和乙酸乙酯）中形成稳定溶液，并引发这些溶液的自燃反应。这些盐在极性质子溶剂中的溶液不会自燃。
