Low-pressure molecular hydrogen storage in semi-clathrate hydrates of quaternary ammonium compounds

Phase relations for tetra-n-butylammonium bromide (TBAB, (C4H9)4N(+)Br(-)) and tetra-nbutylammonium fluoride (TBAF, (C4H9)(4)N+F-) aqueous systems under hydrogen pressure reveal the formation of binary H-2-TBAB and H-2-TBAF semi-clathrate hydrates which are stable at ambient temperatures (<= 29 degrees C) and atmospheric pressure. H-2 is most likely accommodated by occupation of normally vacant dodecahedral (5(12)) cavities, with preliminary analyses suggesting gas contents are an order of magnitude greater than that for binary H-2-THF clathrates at the same pressure (1 MPa).