Reactive insights into the selective dehydrogenation of ethylene diamine bisborane facilitated by phosphonium based Ionic Liquids

Abstract

The thermal dehydrogenation of ethylene diamine bisborane(EDAB) was performed on the COSMO-SAC screened Ionic Liquids namely Trihexyl(tetradecyl)phosphonium bis (2,4,4-trimethylpentyl) phosphinate and Trihexyl(tetradecyl)phosphonium dicyanamide. Dehydrogenation experiments were carried out under vacuum and temperatures of 95 and 105 °C. A maximum yield of 3.25 equivalents of hydrogen was obtained with EDAB/[TDTHP][Phosph] at 105 °C. 1H NMR study confirmed the catalytic role of ILs during dehydrogenation. Further HR-MS analysis of residual products revealed the exact mass of end products. These were corroborated with the formation of oligomeric dehydrogenated EDAB compounds having four and five repeat units which eventually led us in formulating the reaction mechanism.