Regeneration of alkaline metal amidoboranes with high purity
In this manuscript, we report a facile and safe process for highly efficient regeneration of dehydrogenated alkaline metal amidoboranes (MNH2BH3, MAB, M = Li, K), in which CH3OH is employed as a digestion reagent; then LiAlH4 is used as a reduction reagent in the presence of NH4Cl giving ammonia borane (NH3BH3, AB) as the intermediate; finally the generated AB reacts with corresponding metal hydride to complete the whole self-contained cycle. Using this chemical process, MABs are reproduced in a high purity of 98%. The byproducts of regeneration procedure can be converted to mass commodity chemicals as recyclable auxiliary reagents utilizing the recycling pathways. More importantly, our finding of successful scission of dehydrogenated polymeric MAB residues into small molecule B species that guarantees to facilitate the following regeneration process, provides a general strategy for the efficient regeneration for other MAB compounds and a potentially viable route for the chemical recycling of metal-B-N containing hydrogen storage materials.