Experimental Insights into the Thermal Dehydrogenation of Ethylene Diamine Bisborane Using Allyl-Based Ionic Liquids

This work reports the use of allyl-based imidazolium cations for dehydrogenation of ethylene diaminebisborane (EDAB) at three different temperatures, namely, 95, 105, and 115 °C, under vacuum. The allyl-based ionic liquid (IL) was selected by using the infinite dilution activity coefficient (IDAC) as predicted from the COSMO-SAC (COnductor-like Screening MOdel–Segment Activity Coefficient) model. Based on the results of the COSMO-SAC model, the following allyl-based ILs were used for experimentation: 1-allyl-3-methylimidazolium dicyanamide ([AMIM][N(CN) 2 ]), 1-allyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([AMIM][Tf 2 N]), and 1-allyl-3-methylimidazolium bromide ([AMIM][Br]). The highest amount of hydrogen (3.25 equiv) was measured from the EDAB/[AMIM][Br] system at 115 °C. Gas chromatography was conducted to confirm that the gas released was pure hydrogen. To better understand the reaction mechanism of EDAB dehydrogenation, the Reactive Force Field (ReaxFF) method was employed. Further analyses with 1 H and 11 B NMR were performed on pure IL and IL/EDAB complexes to reassert the role of IL as a catalyst. Thermogravimetric analysis was also conducted on pure EDAB, pure IL, and EDAB/IL complexes to understand the weight loss phenomenon with respect to rising temperature.